Flight Control Laws for NASA's Hyper-X Research Vehicle

NASA Technical Reports Server (NTRS)

Davidson, J.; Lallman, F.; McMinn, J. D.; Martin, J.; Pahle, J.; Stephenson, M.; Selmon, J.; Bose, D.

1999-01-01

The goal of the Hyper-X program is to demonstrate and validate technology for design and performance predictions of hypersonic aircraft with an airframe-integrated supersonic-combustion ramjet propulsion system. Accomplishing this goal requires flight demonstration of a hydrogen-fueled scramjet powered hypersonic aircraft. A key enabling technology for this flight demonstration is flight controls. Closed-loop flight control is required to enable a successful stage separation, to achieve and maintain the design condition during the engine test, and to provide a controlled descent. Before the contract award, NASA developed preliminary flight control laws for the Hyper-X to evaluate the feasibility of the proposed scramjet test sequence and descent trajectory. After the contract award, a Boeing/NASA partnership worked to develop the current control laws. This paper presents a description of the Hyper-X Research Vehicle control law architectures with performance and robustness analyses. Assessments of simulated flight trajectories and stability margin analyses demonstrate that these control laws meet the flight test requirements.

Feedback control laws for highly maneuverable aircraft

NASA Technical Reports Server (NTRS)

Garrard, William L.; Balas, Gary J.

1992-01-01

The results of a study of the application of H infinity and mu synthesis techniques to the design of feedback control laws for the longitudinal dynamics of the High Angle of Attack Research Vehicle (HARV) are presented. The objective of this study is to develop methods for the design of feedback control laws which cause the closed loop longitudinal dynamics of the HARV to meet handling quality specifications over the entire flight envelope. Control law designs are based on models of the HARV linearized at various flight conditions. The control laws are evaluated by both linear and nonlinear simulations of typical maneuvers. The fixed gain control laws resulting from both the H infinity and mu synthesis techniques result in excellent performance even when the aircraft performs maneuvers in which the system states vary significantly from their equilibrium design values. Both the H infinity and mu synthesis control laws result in performance which compares favorably with an existing baseline longitudinal control law.

A combined stochastic feedforward and feedback control design methodology with application to autoland design

NASA Technical Reports Server (NTRS)

Halyo, Nesim

1987-01-01

A combined stochastic feedforward and feedback control design methodology was developed. The objective of the feedforward control law is to track the commanded trajectory, whereas the feedback control law tries to maintain the plant state near the desired trajectory in the presence of disturbances and uncertainties about the plant. The feedforward control law design is formulated as a stochastic optimization problem and is embedded into the stochastic output feedback problem where the plant contains unstable and uncontrollable modes. An algorithm to compute the optimal feedforward is developed. In this approach, the use of error integral feedback, dynamic compensation, control rate command structures are an integral part of the methodology. An incremental implementation is recommended. Results on the eigenvalues of the implemented versus designed control laws are presented. The stochastic feedforward/feedback control methodology is used to design a digital automatic landing system for the ATOPS Research Vehicle, a Boeing 737-100 aircraft. The system control modes include localizer and glideslope capture and track, and flare to touchdown. Results of a detailed nonlinear simulation of the digital control laws, actuator systems, and aircraft aerodynamics are presented.

Design and Development of Lateral Flight Director

NASA Technical Reports Server (NTRS)

Kudlinski, Kim E.; Ragsdale, William A.

1999-01-01

The current control law used for the flight director in the Boeing 737 simulator is inadequate with large localizer deviations near the middle marker. Eight different control laws are investigated. A heuristic method is used to design control laws that meet specific performance criteria. The design of each is described in detail. Several tests were performed and compared with the current control law for the flight director. The goal was to design a control law for the flight director that can be used with large localizer deviations near the middle marker, which could be caused by winds or wake turbulence, without increasing its level of complexity.

Some of Indonesian Cyber Law Problems

NASA Astrophysics Data System (ADS)

Machmuddin, D. D.; Pratama, B.

2017-01-01

Cyber regulation is very important to control human interaction within the Internet network in cyber space. On the surface, innovation development in science and technology facilitates human activity. But on the inside, innovation was controlled by new business model. In cyber business activities mingle with individual protection. By this condition, the law should keep the balance of the activities. Cyber law problems, were not particular country concern, but its global concern. This is a good opportunity for developing country to catch up with developed country. Beside this opportunity for talented people in law and technology is become necessity. This paper tries to describe cyber law in Indonesia. As a product of a developing country there are some of weakness that can be explained. Terminology and territory of cyber space is become interesting to discuss, because this two problems can give a broad view on cyber law in Indonesia.

Rolling Maneuver Load Alleviation using active controls

NASA Technical Reports Server (NTRS)

Woods-Vedeler, Jessica A.; Pototzky, Anthony S.

1992-01-01

Rolling Maneuver Load Alleviation (RMLA) has been demonstrated on the Active Flexible Wing (AFW) wind tunnel model in the NASA Langley Transonic Dynamics Tunnel. The design objective was to develop a systematic approach for developing active control laws to alleviate wing incremental loads during roll maneuvers. Using linear load models for the AFW wind-tunnel model which were based on experimental measurements, two RMLA control laws were developed based on a single-degree-of-freedom roll model. The RMLA control laws utilized actuation of outboard control surface pairs to counteract incremental loads generated during rolling maneuvers and actuation of the trailing edge inboard control surface pairs to maintain roll performance. To evaluate the RMLA control laws, roll maneuvers were performed in the wind tunnel at dynamic pressures of 150, 200, and 250 psf and Mach numbers of 0.33, .38 and .44, respectively. Loads obtained during these maneuvers were compared to baseline maneuver loads. For both RMLA controllers, the incremental torsion moments were reduced by up to 60 percent at all dynamic pressures and performance times. Results for bending moment load reductions during roll maneuvers varied. In addition, in a multiple function test, RMLA and flutter suppression system control laws were operated simultaneously during roll maneuvers at dynamic pressures 11 percent above the open-loop flutter dynamic pressure.

Flight test experience and controlled impact of a remotely piloted jet transport aircraft

NASA Technical Reports Server (NTRS)

Horton, Timothy W.; Kempel, Robert W.

1988-01-01

The Dryden Flight Research Center Facility of NASA Ames Research Center (Ames-Dryden) and the FAA conducted the controlled impact demonstration (CID) program using a large, four-engine, remotely piloted jet transport airplane. Closed-loop primary flight was controlled through the existing onboard PB-20D autopilot which had been modified for the CID program. Uplink commands were sent from a ground-based cockpit and digital computer in conjunction with an up-down telemetry link. These uplink commands were received aboard the airplane and transferred through uplink interface systems to the modified PB-20D autopilot. Both proportional and discrete commands were produced by the ground system. Prior to flight tests, extensive simulation was conducted during the development of ground-based digital control laws. The control laws included primary control, secondary control, and racetrack and final approach guidance. Extensive ground checks were performed on all remotely piloted systems; however, piloted flight tests were the primary method and validation of control law concepts developed from simulation. The design, development, and flight testing of control laws and systems required to accomplish the remotely piloted mission are discussed.

Systems development of a stall/spin research facility using remotely controlled/augmented aircraft models. Volume 1: Systems overview

NASA Technical Reports Server (NTRS)

Montoya, R. J.; Jai, A. R.; Parker, C. D.

1979-01-01

A ground based, general purpose, real time, digital control system simulator (CSS) is specified, developed, and integrated with the existing instrumentation van of the testing facility. This CSS is built around a PDP-11/55, and its operational software was developed to meet the dual goal of providing the immediate capability to represent the F-18 drop model control laws and the flexibility for expansion to represent more complex control laws typical of control configured vehicles. Overviews of the two CSS's developed are reviewed as well as the overall system after their integration with the existing facility. Also the latest version of the F-18 drop model control laws (REV D) is described and the changes needed for its incorporation in the digital and analog CSS's are discussed.

Vista/F-16 Multi-Axis Thrust Vectoring (MATV) control law design and evaluation

NASA Technical Reports Server (NTRS)

Zwerneman, W. D.; Eller, B. G.

1994-01-01

For the Multi-Axis Thrust Vectoring (MATV) program, a new control law was developed using multi-axis thrust vectoring to augment the aircraft's aerodynamic control power to provide maneuverability above the normal F-16 angle of attack limit. The control law architecture was developed using Lockheed Fort Worth's offline and piloted simulation capabilities. The final flight control laws were used in flight test to demonstrate tactical benefits gained by using thrust vectoring in air-to-air combat. Differences between the simulator aerodynamics data base and the actual aircraft aerodynamics led to significantly different lateral-directional flying qualities during the flight test program than those identified during piloted simulation. A 'dial-a-gain' flight test control law update was performed in the middle of the flight test program. This approach allowed for inflight optimization of the aircraft's flying qualities. While this approach is not preferred over updating the simulator aerodynamic data base and then updating the control laws, the final selected gain set did provide adequate lateral-directional flying qualities over the MATV flight envelope. The resulting handling qualities and the departure resistance of the aircraft allowed the 422nd_squadron pilots to focus entirely on evaluating the aircraft's tactical utility.

Control Law Design in a Computational Aeroelasticity Environment

NASA Technical Reports Server (NTRS)

Newsom, Jerry R.; Robertshaw, Harry H.; Kapania, Rakesh K.

2003-01-01

A methodology for designing active control laws in a computational aeroelasticity environment is given. The methodology involves employing a systems identification technique to develop an explicit state-space model for control law design from the output of a computational aeroelasticity code. The particular computational aeroelasticity code employed in this paper solves the transonic small disturbance aerodynamic equation using a time-accurate, finite-difference scheme. Linear structural dynamics equations are integrated simultaneously with the computational fluid dynamics equations to determine the time responses of the structure. These structural responses are employed as the input to a modern systems identification technique that determines the Markov parameters of an "equivalent linear system". The Eigensystem Realization Algorithm is then employed to develop an explicit state-space model of the equivalent linear system. The Linear Quadratic Guassian control law design technique is employed to design a control law. The computational aeroelasticity code is modified to accept control laws and perform closed-loop simulations. Flutter control of a rectangular wing model is chosen to demonstrate the methodology. Various cases are used to illustrate the usefulness of the methodology as the nonlinearity of the aeroelastic system is increased through increased angle-of-attack changes.

Design of a candidate flutter suppression control law for DAST ARW-2. [Drones for Aerodynamic and Structural Testing Aeroelastic Research Wing

NASA Technical Reports Server (NTRS)

Adams, W. M., Jr.; Tiffany, S. H.

1983-01-01

A control law is developed to suppress symmetric flutter for a mathematical model of an aeroelastic research vehicle. An implementable control law is attained by including modified LQG (linear quadratic Gaussian) design techniques, controller order reduction, and gain scheduling. An alternate (complementary) design approach is illustrated for one flight condition wherein nongradient-based constrained optimization techniques are applied to maximize controller robustness.

Wind-tunnel evaluation of NASA developed control laws for flutter suppression on a DC-10 derivative wing

NASA Technical Reports Server (NTRS)

Abel, I.; Newsom, J. R.

1981-01-01

Two flutter suppression control laws were synthesized, implemented, and tested on a low speed aeroelastic wing model of a DC-10 derivative. The methodology used to design the control laws is described. Both control laws demonstrated increases in flutter speed in excess of 25 percent above the passive wing flutter speed. The effect of variations in gain and phase on the closed loop performance was measured and compared with analytical predictions. The analytical results are in good agreement with experimental data.

An improved lateral control wheel steering law for the Transport Systems Research Vehicle (TSRV)

NASA Technical Reports Server (NTRS)

Ragsdale, W. A.

1992-01-01

A lateral control wheel steering law with improved performance was developed for the Transport Systems Research Vehicle (TSRV) simulation and used in the Microwave Landing System research project. The control law converted rotational hand controller inputs into roll rate commands, manipulated ailerons, spoilers, and the rudder to achieve the desired roll rates. The system included automatic turn coordination, track angle hold, and autopilot/autoland modes. The resulting control law produced faster roll rates (15 degrees/sec), quicker response to command reversals, and safer bank angle limits, while using a more concise program code.

Precomputed state dependent digital control of a nuclear rocket engine

NASA Technical Reports Server (NTRS)

Johnson, M. R.

1972-01-01

A control method applicable to multiple-input multiple-output nonlinear time-invariant systems in which desired behavior can be expressed explicitly as a trajectory in system state space is developed. The precomputed state dependent control method is basically a synthesis technique in which a suboptimal control law is developed off-line, prior to system operation. This law is obtained by conducting searches at a finite number of points in state space, in the vicinity of some desired trajectory, to obtain a set of constant control vectors which tend to return the system to the desired trajectory. These vectors are used to evaluate the unknown coefficients in a control law having an assumed hyperellipsoidal form. The resulting coefficients constitute the heart of the controller and are used in the on-line computation of control vectors. Two examples of PSDC are given prior to the more detailed description of the NERVA control system development.

Comparative study of flare control laws

NASA Technical Reports Server (NTRS)

Nadkarni, A. A.

1981-01-01

The development of a digital, three dimensional, automatic control law designed to achieve an optimal transition of a B-737 aircraft between glide slope conditions and the desired final touchdown condition is presented. The digital control law is a time invariant, state estimate feedback law, and the design is capable of using the microwave landing system. Major emphasis is placed on the reduction of aircraft noise in communities surroundings airports, the reduction of fuel consumption, the reduction of the effects of adverse weather conditions on aircraft operations, and the efficient use of airspace in congested terminal areas. Attention is also given to the development of the capability to perform automatic flares from steep glide slopes to precise touchdown locations.

Discrete-Time Local Value Iteration Adaptive Dynamic Programming: Admissibility and Termination Analysis.

PubMed

Wei, Qinglai; Liu, Derong; Lin, Qiao

In this paper, a novel local value iteration adaptive dynamic programming (ADP) algorithm is developed to solve infinite horizon optimal control problems for discrete-time nonlinear systems. The focuses of this paper are to study admissibility properties and the termination criteria of discrete-time local value iteration ADP algorithms. In the discrete-time local value iteration ADP algorithm, the iterative value functions and the iterative control laws are both updated in a given subset of the state space in each iteration, instead of the whole state space. For the first time, admissibility properties of iterative control laws are analyzed for the local value iteration ADP algorithm. New termination criteria are established, which terminate the iterative local ADP algorithm with an admissible approximate optimal control law. Finally, simulation results are given to illustrate the performance of the developed algorithm.In this paper, a novel local value iteration adaptive dynamic programming (ADP) algorithm is developed to solve infinite horizon optimal control problems for discrete-time nonlinear systems. The focuses of this paper are to study admissibility properties and the termination criteria of discrete-time local value iteration ADP algorithms. In the discrete-time local value iteration ADP algorithm, the iterative value functions and the iterative control laws are both updated in a given subset of the state space in each iteration, instead of the whole state space. For the first time, admissibility properties of iterative control laws are analyzed for the local value iteration ADP algorithm. New termination criteria are established, which terminate the iterative local ADP algorithm with an admissible approximate optimal control law. Finally, simulation results are given to illustrate the performance of the developed algorithm.

The millennium development goals and tobacco control.

PubMed

Collishaw, Neil E

2010-03-01

The eight Millennium Development Goals were proposed by the UN Secretary-General in 2001. They are goals with measurable targets to be achieved by 2015 or earlier. The Goals were distilled from the 2000 United Nations Millennium Declaration, a sweeping statement of development values, principles, objectives and proposed actions. The Framework Convention on Tobacco Control (FCTC) is a demonstrable translation of some of the ideas in the Millennium Declaration into reality. With 165(i) Parties, the FCTC does more than just improve global tobacco control: * The FCTC contributes to achievement of many of the Millennium Development Goals, and benefits from success in implementation of the Goals in other sectors. * The treaty itself is a demonstration of strengthened international and national rule of law, central tenets of the Millennium Declaration. * The FCTC expands international law into the health sector and provides better balance of international law among economic, environmental, social and health sectors. The Millennium Declaration calls for a more equitable distribution of the benefits of globalization, and the FCTC delivers this result. * The FCTC provides a model for addressing other unsolved global problems through greater use of international law. Alcohol control and dietary improvements including greater control of empty calories in manufactured foods are examples of problems that may benefit from greater governance by international law. Were that to come to pass, those new treaties would also improve implementation of the Millennium Declaration and the Millennium Development Goals.

On Using Exponential Parameter Estimators with an Adaptive Controller

NASA Technical Reports Server (NTRS)

Patre, Parag; Joshi, Suresh M.

2011-01-01

Typical adaptive controllers are restricted to using a specific update law to generate parameter estimates. This paper investigates the possibility of using any exponential parameter estimator with an adaptive controller such that the system tracks a desired trajectory. The goal is to provide flexibility in choosing any update law suitable for a given application. The development relies on a previously developed concept of controller/update law modularity in the adaptive control literature, and the use of a converse Lyapunov-like theorem. Stability analysis is presented to derive gain conditions under which this is possible, and inferences are made about the tracking error performance. The development is based on a class of Euler-Lagrange systems that are used to model various engineering systems including space robots and manipulators.

Development of ADOCS controllers and control laws. Volume 2: Literature review and preliminary analysis

NASA Technical Reports Server (NTRS)

Landis, Kenneth H.; Glusman, Steven I.

1985-01-01

The Advanced Cockpit Controls/Advanced Flight Control System (ACC/AFCS) study was conducted by the Boeing Vertol Company as part of the Army's Advanced Digital/Optical Control System (ADOCS) program. Specifically, the ACC/AFCS investigation was aimed at developing the flight control laws for the ADOCS demonstrator aircraft which will provide satisfactory handling qualities for an attack helicopter mission. The three major elements of design considered are as follows: Pilot's integrated Side-Stick Controller (SSC) -- Number of axes controlled; force/displacement characteristics; ergonomic design. Stability and Control Augmentation System (SCAS)--Digital flight control laws for the various mission phases; SCAS mode switching logic. Pilot's Displays--For night/adverse weather conditions, the dynamics of the superimposed symbology presented to the pilot in a format similar to the Advanced Attack Helicopter (AAH) Pilot Night Vision System (PNVS) for each mission phase as a function of ACAS characteristics; display mode switching logic. Findings from the literature review and the analysis and synthesis of desired control laws are reported in Volume 2. Conclusions drawn from pilot rating data and commentary were used to formulate recommendations for the ADOCS demonstrator flight control system design. The ACC/AFCS simulation data also provide an extensive data base to aid the development of advanced flight control system design for future V/STOL aircraft.

Technology Integration (Task 20) Aeroservoelastic Modeling and Design Studies. Part A; Evaluation of Aeroservoelastic Effects on Flutter and Dynamic Gust Response

NASA Technical Reports Server (NTRS)

Nagaraja, K. S.; Kraft, R. H.

1999-01-01

The HSCT Flight Controls Group has developed longitudinal control laws, utilizing PTC aeroelastic flexible models to minimize aeroservoelastic interaction effects, for a number of flight conditions. The control law design process resulted in a higher order controller and utilized a large number of sensors distributed along the body for minimizing the flexibility effects. Processes were developed to implement these higher order control laws for performing the dynamic gust loads and flutter analyses. The processes and its validation were documented in Reference 2, for selected flight condition. The analytical results for additional flight conditions are presented in this document for further validation.

The development of optimal control laws for orbiting tethered platform systems

NASA Technical Reports Server (NTRS)

Bainum, P. M.; Woodard, S.; Juang, J.-N.

1986-01-01

A mathematical model of the open and closed loop in-orbit plane dynamics of a space platform-tethered-subsatellite system is developed. The system consists of a rigid platform from which an (assumed massless) tether is deploying (retrieving) a subsatellite from an attachment point which is, in general, offset from the platform's mass center. A Lagrangian formulation yields equations describing platform pitch, subsatellite tether-line swing, and varying tether length motions. These equations are linearized about the nominal station keeping motion. Control can be provided by both modulation of the tether tension level and by a momentum type platform-mounted device; system controllability depends on the presence of both control inputs. Stability criteria are developed in terms of the control law gains, the platform inertia ratio, and tether offset parameter. Control law gains are obtained based on linear quadratic regulator techniques. Typical transient responses of both the state and required control effort are presented.

The development of optimal control laws for orbiting tethered platform systems

NASA Technical Reports Server (NTRS)

Bainum, P. M.

1986-01-01

A mathematical model of the open and closed loop in orbit plane dynamics of a space platform-tethered-subsatellite system is developed. The system consists of a rigid platform from which an (assumed massless) tether is deploying (retrieving) a subsatellite from an attachment point which is, in general, offset from the platform's mass center. A Langrangian formulation yields equations describing platform pitch, subsatellite tetherline swing, and varying tether length motions. These equations are linearized about the nominal station keeping motion. Control can be provided by both modulation of the tether tension level and by a momentum type platform-mounted device; system controllability depends on the presence of both control inputs. Stability criteria are developed in terms of the control law gains, the platform inertia ratio, and tether offset parameter. Control law gains are obtained based on linear quadratic regulator techniques. Typical transient responses of both the state and required control effort are presented.

Analysis of Control Strategies for Aircraft Flight Upset Recovery

NASA Technical Reports Server (NTRS)

Crespo, Luis G.; Kenny, Sean P.; Cox, David E.; Muri, Daniel G.

2012-01-01

This paper proposes a framework for studying the ability of a control strategy, consisting of a control law and a command law, to recover an aircraft from ight conditions that may extend beyond the normal ight envelope. This study was carried out (i) by evaluating time responses of particular ight upsets, (ii) by evaluating local stability over an equilibrium manifold that included stall, and (iii) by bounding the set in the state space from where the vehicle can be safely own to wings-level ight. These states comprise what will be called the safely recoverable ight envelope (SRFE), which is a set containing the aircraft states from where a control strategy can safely stabilize the aircraft. By safe recovery it is implied that the tran- sient response stays between prescribed limits before converging to a steady horizontal ight. The calculation of the SRFE bounds yields the worst-case initial state corresponding to each control strategy. This information is used to compare alternative recovery strategies, determine their strengths and limitations, and identify the most e ective strategy. In regard to the control law, the authors developed feedback feedforward laws based on the gain scheduling of multivariable controllers. In regard to the command law, which is the mechanism governing the exogenous signals driving the feed- forward component of the controller, we developed laws with a feedback structure that combines local stability and transient response considera- tions. The upset recovery of the Generic Transport Model, a sub-scale twin-engine jet vehicle developed by NASA Langley Research Center, is used as a case study.

Simulation Environment for Orion Launch Abort System Control Design Studies

NASA Technical Reports Server (NTRS)

McMinn, J. Dana; Jackson, E. Bruce; Christhilf, David M.

2007-01-01

The development and use of an interactive environment to perform control system design and analysis of the proposed Crew Exploration Vehicle Launch Abort System is described. The environment, built using a commercial dynamic systems design package, includes use of an open-source configuration control software tool and a collaborative wiki to coordinate between the simulation developers, control law developers and users. A method for switching between multiple candidate control laws and vehicle configurations is described. Aerodynamic models, especially in a development program, change rapidly, so a means for automating the implementation of new aerodynamic models is described.

Hypersonic vehicle control law development using H(infinity) and micron-synthesis

NASA Technical Reports Server (NTRS)

Gregory, Irene M.; Mcminn, John D.; Shaughnessy, John D.; Chowdhry, Rajiv S.

1993-01-01

Hypersonic vehicle control law development using H(infinity) and mu-synthesis is discussed. Airbreathing SSTO vehicles has a mutli-faceted mission that includes orbital operations, as well as re-entry and descent culminating in horizontal landing. However, the most challenging part of the operations is the ascent to orbit. The airbreathing propulsion requires lengthy atmospheric flight that may last as long as 30 minutes and take the vehicle half way around the globe. The vehicles's ascent is characterized by tight payload to orbit margins which translate into minimum fuel orbit as the performance criteria. Issues discussed include: SSTO airbreathing vehicle issues; control system performance requirements; robust control law framework; H(infinity) controller frequency analysis; and mu controller frequency analysis.

On the shape and orientation control of an orbiting shallow spherical shell structure

NASA Technical Reports Server (NTRS)

Bainum, P. M.; Reddy, A. S. S. R.

1982-01-01

The dynamics of orbiting shallow flexible spherical shell structures under the influence of control actuators was studied. Control laws are developed to provide both attitude and shape control of the structure. The elastic modal frequencies for the fundamental and lower modes are closely grouped due to the effect of the shell curvature. The shell is gravity stabilized by a spring loaded dumbbell type damper attached at its apex. Control laws are developed based on the pole clustering techniques. Savings in fuel consumption can be realized by using the hybrid shell dumbbell system together with point actuators. It is indicated that instability may result by not including the orbital and first order gravity gradient effects in the plant prior to control law design.

A variable-gain output feedback control design methodology

NASA Technical Reports Server (NTRS)

Halyo, Nesim; Moerder, Daniel D.; Broussard, John R.; Taylor, Deborah B.

1989-01-01

A digital control system design technique is developed in which the control system gain matrix varies with the plant operating point parameters. The design technique is obtained by formulating the problem as an optimal stochastic output feedback control law with variable gains. This approach provides a control theory framework within which the operating range of a control law can be significantly extended. Furthermore, the approach avoids the major shortcomings of the conventional gain-scheduling techniques. The optimal variable gain output feedback control problem is solved by embedding the Multi-Configuration Control (MCC) problem, previously solved at ICS. An algorithm to compute the optimal variable gain output feedback control gain matrices is developed. The algorithm is a modified version of the MCC algorithm improved so as to handle the large dimensionality which arises particularly in variable-gain control problems. The design methodology developed is applied to a reconfigurable aircraft control problem. A variable-gain output feedback control problem was formulated to design a flight control law for an AFTI F-16 aircraft which can automatically reconfigure its control strategy to accommodate failures in the horizontal tail control surface. Simulations of the closed-loop reconfigurable system show that the approach produces a control design which can accommodate such failures with relative ease. The technique can be applied to many other problems including sensor failure accommodation, mode switching control laws and super agility.

High alpha feedback control for agile half-loop maneuvers of the F-18 airplane

NASA Technical Reports Server (NTRS)

Stalford, Harold

1988-01-01

A nonlinear feedback control law for the F/A-18 airplane that provides time-optimal or agile maneuvering of the half-loop maneuver at high angles of attack is given. The feedback control law was developed using the mathematical approach of singular perturbations, in which the control devices considered were conventional aerodynamic control surfaces and thrusting. The derived nonlinear control law was used to simulate F/A-18 half-loop maneuvers. The simulated results at Mach 0.6 and 0.9 compared well with pilot simulations conducted at NASA.

GPC-Based Stable Reconfigurable Control

NASA Technical Reports Server (NTRS)

Soloway, Don; Shi, Jian-Jun; Kelkar, Atul

2004-01-01

This paper presents development of multi-input multi-output (MIMO) Generalized Pre-dictive Control (GPC) law and its application to reconfigurable control design in the event of actuator saturation. A Controlled Auto-Regressive Integrating Moving Average (CARIMA) model is used to describe the plant dynamics. The control law is derived using input-output description of the system and is also related to the state-space form of the model. The stability of the GPC control law without reconfiguration is first established using Riccati-based approach and state-space formulation. A novel reconfiguration strategy is developed for the systems which have actuator redundancy and are faced with actuator saturation type failure. An elegant reconfigurable control design is presented with stability proof. Several numerical examples are presented to demonstrate the application of various results.

Optimization of motion control laws for tether crawler or elevator systems

NASA Technical Reports Server (NTRS)

Swenson, Frank R.; Von Tiesenhausen, Georg

1988-01-01

Based on the proposal of a motion control law by Lorenzini (1987), a method is developed for optimizing motion control laws for tether crawler or elevator systems in terms of the performance measures of travel time, the smoothness of acceleration and deceleration, and the maximum values of velocity and acceleration. The Lorenzini motion control law, based on powers of the hyperbolic tangent function, is modified by the addition of a constant-velocity section, and this modified function is then optimized by parameter selections to minimize the peak acceleration value for a selected travel time or to minimize travel time for the selected peak values of velocity and acceleration. It is shown that the addition of a constant-velocity segment permits further optimization of the motion control law performance.

Design of control laws for flutter suppression based on the aerodynamic energy concept and comparisons with other design methods

NASA Technical Reports Server (NTRS)

Nissim, Eli

1990-01-01

The aerodynamic energy method is used to synthesize control laws for NASA's drone for aerodynamic and structural testing-aerodynamic research wing 1 (DAST-ARW1) mathematical model. The performance of these control laws in terms of closed-loop flutter dynamic pressure, control surface activity, and robustness is compared with other control laws that relate to the same model. A control law synthesis technique that makes use of the return difference singular values is developed. It is based on the aerodynamic energy approach and is shown to yield results that are superior to those results given in the literature and are based on optimal control theory. Nyquist plots are presented, together with a short discussion regarding the relative merits of the minimum singular value as a measure of robustness as compared with the more traditional measure involving phase and gain margins.

Design of control laws for flutter suppression based on the aerodynamic energy concept and comparisons with other design methods

NASA Technical Reports Server (NTRS)

Nissim, E.

1989-01-01

The aerodynamic energy method is used in this paper to synthesize control laws for NASA's Drone for Aerodynamic and Structural Testing-Aerodynamic Research Wing 1 (DAST-ARW1) mathematical model. The performance of these control laws in terms of closed-loop flutter dynamic pressure, control surface activity, and robustness is compared against other control laws that appear in the literature and relate to the same model. A control law synthesis technique that makes use of the return difference singular values is developed in this paper. it is based on the aerodynamic energy approach and is shown to yield results superior to those given in the literature and based on optimal control theory. Nyquist plots are presented together with a short discussion regarding the relative merits of the minimum singular value as a measure of robustness, compared with the more traditional measure of robustness involving phase and gain margins.

A method for obtaining reduced-order control laws for high-order systems using optimization techniques

NASA Technical Reports Server (NTRS)

Mukhopadhyay, V.; Newsom, J. R.; Abel, I.

1981-01-01

A method of synthesizing reduced-order optimal feedback control laws for a high-order system is developed. A nonlinear programming algorithm is employed to search for the control law design variables that minimize a performance index defined by a weighted sum of mean-square steady-state responses and control inputs. An analogy with the linear quadractic Gaussian solution is utilized to select a set of design variables and their initial values. To improve the stability margins of the system, an input-noise adjustment procedure is used in the design algorithm. The method is applied to the synthesis of an active flutter-suppression control law for a wind tunnel model of an aeroelastic wing. The reduced-order controller is compared with the corresponding full-order controller and found to provide nearly optimal performance. The performance of the present method appeared to be superior to that of two other control law order-reduction methods. It is concluded that by using the present algorithm, nearly optimal low-order control laws with good stability margins can be synthesized.

Digital robust control law synthesis using constrained optimization

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivekananda

1989-01-01

Development of digital robust control laws for active control of high performance flexible aircraft and large space structures is a research area of significant practical importance. The flexible system is typically modeled by a large order state space system of equations in order to accurately represent the dynamics. The active control law must satisy multiple conflicting design requirements and maintain certain stability margins, yet should be simple enough to be implementable on an onboard digital computer. Described here is an application of a generic digital control law synthesis procedure for such a system, using optimal control theory and constrained optimization technique. A linear quadratic Gaussian type cost function is minimized by updating the free parameters of the digital control law, while trying to satisfy a set of constraints on the design loads, responses and stability margins. Analytical expressions for the gradients of the cost function and the constraints with respect to the control law design variables are used to facilitate rapid numerical convergence. These gradients can be used for sensitivity study and may be integrated into a simultaneous structure and control optimization scheme.

Development and demonstration of a flutter-suppression system using active controls. [wind tunnel tests

NASA Technical Reports Server (NTRS)

Sandford, M. C.; Abel, I.; Gray, D. L.

1975-01-01

The application of active control technology to suppress flutter was demonstrated successfully in the transonic dynamics tunnel with a delta-wing model. The model was a simplified version of a proposed supersonic transport wing design. An active flutter suppression method based on an aerodynamic energy criterion was verified by using three different control laws. The first two control laws utilized both leading-edge and trailing-edge active control surfaces, whereas the third control law required only a single trailing-edge active control surface. At a Mach number of 0.9 the experimental results demonstrated increases in the flutter dynamic pressure from 12.5 percent to 30 percent with active controls. Analytical methods were developed to predict both open-loop and closed-loop stability, and the results agreed reasonably well with the experimental results.

Asymptotic Linearity of Optimal Control Modification Adaptive Law with Analytical Stability Margins

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.

2010-01-01

Optimal control modification has been developed to improve robustness to model-reference adaptive control. For systems with linear matched uncertainty, optimal control modification adaptive law can be shown by a singular perturbation argument to possess an outer solution that exhibits a linear asymptotic property. Analytical expressions of phase and time delay margins for the outer solution can be obtained. Using the gradient projection operator, a free design parameter of the adaptive law can be selected to satisfy stability margins.

Results of an integrated structure-control law design sensitivity analysis

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.

1988-01-01

Next generation air and space vehicle designs are driven by increased performance requirements, demanding a high level of design integration between traditionally separate design disciplines. Interdisciplinary analysis capabilities have been developed, for aeroservoelastic aircraft and large flexible spacecraft control for instance, but the requisite integrated design methods are only beginning to be developed. One integrated design method which has received attention is based on hierarchal problem decompositions, optimization, and design sensitivity analyses. This paper highlights a design sensitivity analysis method for Linear Quadratic Cost, Gaussian (LQG) optimal control laws, which predicts change in the optimal control law due to changes in fixed problem parameters using analytical sensitivity equations. Numerical results of a design sensitivity analysis for a realistic aeroservoelastic aircraft example are presented. In this example, the sensitivity of the optimally controlled aircraft's response to various problem formulation and physical aircraft parameters is determined. These results are used to predict the aircraft's new optimally controlled response if the parameter was to have some other nominal value during the control law design process. The sensitivity results are validated by recomputing the optimal control law for discrete variations in parameters, computing the new actual aircraft response, and comparing with the predicted response. These results show an improvement in sensitivity accuracy for integrated design purposes over methods which do not include changess in the optimal control law. Use of the analytical LQG sensitivity expressions is also shown to be more efficient that finite difference methods for the computation of the equivalent sensitivity information.

Feedback control laws for highly maneuverable aircraft

NASA Technical Reports Server (NTRS)

Garrard, William L.; Balas, Gary J.

1994-01-01

During the first half of the year, the investigators concentrated their efforts on completing the design of control laws for the longitudinal axis of the HARV. During the second half of the year they concentrated on the synthesis of control laws for the lateral-directional axes. The longitudinal control law design efforts can be briefly summarized as follows. Longitudinal control laws were developed for the HARV using mu synthesis design techniques coupled with dynamic inversion. An inner loop dynamic inversion controller was used to simplify the system dynamics by eliminating the aerodynamic nonlinearities and inertial cross coupling. Models of the errors resulting from uncertainties in the principal longitudinal aerodynamic terms were developed and included in the model of the HARV with the inner loop dynamic inversion controller. This resulted in an inner loop transfer function model which was an integrator with the modeling errors characterized as uncertainties in gain and phase. Outer loop controllers were then designed using mu synthesis to provide robustness to these modeling errors and give desired response to pilot inputs. Both pitch rate and angle of attack command following systems were designed. The following tasks have been accomplished for the lateral-directional controllers: inner and outer loop dynamic inversion controllers have been designed; an error model based on a linearized perturbation model of the inner loop system was derived; controllers for the inner loop system have been designed, using classical techniques, that control roll rate and Dutch roll response; the inner loop dynamic inversion and classical controllers have been implemented on the six degree of freedom simulation; and lateral-directional control allocation scheme has been developed based on minimizing required control effort.

Development of a Model Following Control Law for Inflight Simulation and Flight Controls Research

NASA Technical Reports Server (NTRS)

Takahashi, Mark; Fletcher, Jay; Aiken, Edwin W. (Technical Monitor)

1994-01-01

The U.S. Army and NASA are currently developing the Rotorcraft Aircrew Systems Concepts Airborne Laboratory (RASCAL) at the Ames Research Center. RASCAL, shown in Figure 1, is a UH-60, which is being modified in a phased development program to have a research fly-by-wire flight control system, and an advanced navigation research platform. An important part of the flight controls and handling qualities research on RASCAL will be an FCS design for the aircraft to achieve high bandwidth control responses and disturbance rejection characteristics. Initially, body states will be used as feedbacks, but research into the use of rotor states will also be considered in later stages to maximize agility and maneuverability. In addition to supporting flight controls research, this FCS design will serve as the inflight simulation control law to support basic handling qualities, guidance, and displays research. Research in high bandwidth controls laws is motivated by the desire to improve the handling qualities in aggressive maneuvering and in severely degraded weather conditions. Naturally, these advantages will also improve the quality of the model following, thereby improving the inflight simulation capabilities of the research vehicle. High bandwidth in the control laws provides tighter tracking allowing for higher response bandwidths which can meet handling qualities requirements for aggressive maneuvering. System sensitivity is also reduced preventing variations in the response from the vehicle due to changing flight conditions. In addition, improved gust rejection will result from this reduced sensitivity. The gust rejection coupled with a highly stable system will make more precise maneuvering and pointing possible in severely degraded weather conditions. The difficulty in achieving higher bandwidths from the control laws in the feedback and in the responses arises from the complexity of the models that are needed to produce a satisfactory design. In this case, high quality models that include rotor dynamics in a physically meaningful context must be available. A non-physical accounting of the rotor, such as lumping the effect as a time delay, is not likely to produce the desired results. High order simulation models based on first principals are satisfactory for the initial design phase in order to work out the control law design concept and get an initial set of gains. These models, however, have known deficiencies, which must be resolved in the final control law design. The error in the pitch-roll cross coupling is one notable deficiency that even sophisticated rotorcraft models including complex wake aerodynamics have yet to capture successfully. This error must be accounted for to achieve the desired decoupling. The approach to design the proposed inflight simulation control law is based on using a combination of simulation and identified models. The linear and nonlinear higher order models were used to develop an explicit model following control structure. This structure was developed to accommodate the design of control laws compliant to many of the quantitative requirements in ADS-33C. Furthermore, it also allows for control law research using rotor-state feedback and other design methodologies such as Quantitative Feedback and H-Infinity. Final gain selection will be based on higher order identified models which include rotor degrees of freedom.

Development of a Test Facility for Air Revitalization Technology Evaluation

NASA Technical Reports Server (NTRS)

Lu, Sao-Dung; Lin, Amy; Campbell, Melissa; Smith, Frederick

2006-01-01

An active fault tolerant control (FTC) law is generally sensitive to false identification since the control gain is reconfigured for fault occurrence. In the conventional FTC law design procedure, dynamic variations due to false identification are not considered. In this paper, an FTC synthesis method is developed in order to consider possible variations of closed-loop dynamics under false identification into the control design procedure. An active FTC synthesis problem is formulated into an LMI optimization problem to minimize the upper bound of the induced-L2 norm which can represent the worst-case performance degradation due to false identification. The developed synthesis method is applied for control of the longitudinal motions of FASER (Free-flying Airplane for Subscale Experimental Research). The designed FTC law of the airplane is simulated for pitch angle command tracking under a false identification case.

Adaptive neural network motion control for aircraft under uncertainty conditions

NASA Astrophysics Data System (ADS)

Efremov, A. V.; Tiaglik, M. S.; Tiumentsev, Yu V.

2018-02-01

We need to provide motion control of modern and advanced aircraft under diverse uncertainty conditions. This problem can be solved by using adaptive control laws. We carry out an analysis of the capabilities of these laws for such adaptive systems as MRAC (Model Reference Adaptive Control) and MPC (Model Predictive Control). In the case of a nonlinear control object, the most efficient solution to the adaptive control problem is the use of neural network technologies. These technologies are suitable for the development of both a control object model and a control law for the object. The approximate nature of the ANN model was taken into account by introducing additional compensating feedback into the control system. The capabilities of adaptive control laws under uncertainty in the source data are considered. We also conduct simulations to assess the contribution of adaptivity to the behavior of the system.

The analysis and large-angle control of a flexible beam using an adaptive truss

NASA Technical Reports Server (NTRS)

Warrington, Thomas J.; Clark, William W.; Robertshaw, Harry H.; Horner, C. Garnett

1991-01-01

This preliminary study of an adaptive truss slewing problem investigates the static positioning of an adaptive truss at slewed orientations and the dynamic vibrations of an attached flexible beam. A nonlinear model of an adaptive truss and flexible beam is derived. Linear control laws are developed and simulated for various truss configurations. Results show the linear control laws developed at a slewed configuration perform best at that configuration.

Comparing Interval Management Control Laws for Steady-State Errors and String Stability

NASA Technical Reports Server (NTRS)

Weitz, Lesley A.; Swieringa, Kurt A.

2018-01-01

Interval Management (IM) is a future airborne spacing concept that leverages avionics to provide speed guidance to an aircraft to achieve and maintain a specified spacing interval from another aircraft. The design of a speed control law to achieve the spacing goal is a key aspect in the research and development of the IM concept. In this paper, two control laws that are used in much of the contemporary IM research are analyzed and compared to characterize steady-state errors and string stability. Numerical results are used to illustrate how the choice of control laws gains impacts the size of steady-state errors and string performance and the potential trade-offs between those performance characteristics.

Nonlinear Dynamic Inversion Baseline Control Law: Architecture and Performance Predictions

NASA Technical Reports Server (NTRS)

Miller, Christopher J.

2011-01-01

A model reference dynamic inversion control law has been developed to provide a baseline control law for research into adaptive elements and other advanced flight control law components. This controller has been implemented and tested in a hardware-in-the-loop simulation; the simulation results show excellent handling qualities throughout the limited flight envelope. A simple angular momentum formulation was chosen because it can be included in the stability proofs for many basic adaptive theories, such as model reference adaptive control. Many design choices and implementation details reflect the requirements placed on the system by the nonlinear flight environment and the desire to keep the system as basic as possible to simplify the addition of the adaptive elements. Those design choices are explained, along with their predicted impact on the handling qualities.

Active load control during rolling maneuvers. [performed in the Langley Transonic Dynamics Tunnel

NASA Technical Reports Server (NTRS)

Woods-Vedeler, Jessica A.; Pototzky, Anthony S.; Hoadley, Sherwood T.

1994-01-01

A rolling maneuver load alleviation (RMLA) system has been demonstrated on the active flexible wing (AFW) wind tunnel model in the Langley Transonic Dynamics Tunnel (TDT). The objective was to develop a systematic approach for designing active control laws to alleviate wing loads during rolling maneuvers. Two RMLA control laws were developed that utilized outboard control-surface pairs (leading and trailing edge) to counteract the loads and that used inboard trailing-edge control-surface pairs to maintain roll performance. Rolling maneuver load tests were performed in the TDT at several dynamic pressures that included two below and one 11 percent above open-loop flutter dynamic pressure. The RMLA system was operated simultaneously with an active flutter suppression system above open-loop flutter dynamic pressure. At all dynamic pressures for which baseline results were obtained, torsion-moment loads were reduced for both RMLA control laws. Results for bending-moment load reductions were mixed; however, design equations developed in this study provided conservative estimates of load reduction in all cases.

Evaluation of Aeroservoelastic Effects on Flutter

NASA Technical Reports Server (NTRS)

Nagaraja, K. S.; Kraft, raymond; Felt, Larry

1998-01-01

The HSCT Flight Controls Group is developing a longitudinal control law, known as Gamma-dot / V, for the NASA HSR program. Currently, this control law is based on a quasi-steady aeroelastic (QSAE) model of the vehicle. This control law was implemented into the p-k flutter analysis process for closed loop aeroservoelastic analysis. The available flexible models, developed for the TCA aeroelastic analysis, were used to assess the effect of control laws on flutter at several different Mach numbers and mass conditions. Significant structures and flight control system interaction was observed during the initial assessment. Figures 1 and 2 present a summary of the effect of total closed loop gain and phase on flutter mechanisms, based on ideal sensors and real sensors, for Mach 0.95 and mass M02 condition. Control laws based on ideal sensors gave rise to increased coupling between the rigid body short period mode and the first symmetric elastic mode. This reduced the stability margins for the first elastic mode and does not meet the required 6 dB gain margin requirement. The effect of "real" sensors significantly increased the structures and control system interactions. This caused the elastic,modes to be highly unstable throughout most of the flight envelope. State-space models were developed for several conditions and then MATLAB program was used for the aeroservoelastic stability analysis. These results provided an independent verification of the p-k flutter analysis findings. Good overall agreement was observed between the p-k flutter analysis and state-space model results for both damping and frequency comparisons. These results are also included in this document.

The design of digital-adaptive controllers for VTOL aircraft

NASA Technical Reports Server (NTRS)

Stengel, R. F.; Broussard, J. R.; Berry, P. W.

1976-01-01

Design procedures for VTOL automatic control systems have been developed and are presented. Using linear-optimal estimation and control techniques as a starting point, digital-adaptive control laws have been designed for the VALT Research Aircraft, a tandem-rotor helicopter which is equipped for fully automatic flight in terminal area operations. These control laws are designed to interface with velocity-command and attitude-command guidance logic, which could be used in short-haul VTOL operations. Developments reported here include new algorithms for designing non-zero-set-point digital regulators, design procedures for rate-limited systems, and algorithms for dynamic control trim setting.

Integrated Power and Attitude Control for a Spacecraft with Flywheels and Control Moment Gyroscopes

NASA Technical Reports Server (NTRS)

Roithmayr, Carlos M.; Karlgaard, Christopher D.; Kumar, Renjith R.; Bose, David M.

2003-01-01

A law is designed for simultaneous control of the orientation of an Earth-pointing spacecraft, the energy stored by counter-rotating flywheels, and the angular momentum of the flywheels and control moment gyroscopes used together as all integrated set of actuators for attitude control. General. nonlinear equations of motion are presented in vector-dyadic form, and used to obtain approximate expressions which are then linearized in preparation for design of control laws that include feedback of flywheel kinetic energy error as it means of compensating for damping exerted by rotor bearings. Two flywheel 'steering laws' are developed such that torque commanded by all attitude control law is achieved while energy is stored or discharged at the required rate. Using the International Space Station as an example, numerical simulations are performed to demonstrate control about a torque equilibrium attitude and illustrate the benefits of kinetic energy error feedback.

Hardware demonstration of flexible beam control

NASA Technical Reports Server (NTRS)

Schaechter, D. B.

1980-01-01

An experiment employing a pinned-free flexible beam has been constructed to demonstrate and verify several facets of the control of flexible structures. The desired features of the experiment are to demonstrate active shape control, active dynamic control, adaptive control, various control law design approaches, and associated hardware requirements and mechanization difficulties. This paper contains the analytical work performed in support of the facility development, the final design specifications, control law synthesis, and some preliminary results.

Gain-Scheduled Fault Tolerance Control Under False Identification

NASA Technical Reports Server (NTRS)

Shin, Jong-Yeob; Belcastro, Christine (Technical Monitor)

2006-01-01

An active fault tolerant control (FTC) law is generally sensitive to false identification since the control gain is reconfigured for fault occurrence. In the conventional FTC law design procedure, dynamic variations due to false identification are not considered. In this paper, an FTC synthesis method is developed in order to consider possible variations of closed-loop dynamics under false identification into the control design procedure. An active FTC synthesis problem is formulated into an LMI optimization problem to minimize the upper bound of the induced-L2 norm which can represent the worst-case performance degradation due to false identification. The developed synthesis method is applied for control of the longitudinal motions of FASER (Free-flying Airplane for Subscale Experimental Research). The designed FTC law of the airplane is simulated for pitch angle command tracking under a false identification case.

Control definition study for advanced vehicles

NASA Technical Reports Server (NTRS)

Lapins, M.; Martorella, R. P.; Klein, R. W.; Meyer, R. C.; Sturm, M. J.

1983-01-01

The low speed, high angle of attack flight mechanics of an advanced, canard-configured, supersonic tactical aircraft designed with moderate longitudinal relaxed static stability (Static Margin, SM = 16% C sub W at M = 0.4) was investigated. Control laws were developed for the longitudinal axis (""G'' or maneuver and angle of attack command systems) and for the lateral/directional axes. The performance of these control laws was examined in engineering simulation. A canard deflection/rate requirement study was performed as part of the ""G'' command law evaluation at low angles of attack. Simulated coupled maneuvers revealed the need for command limiters in all three aircraft axes to prevent departure from controlled flight. When modified with command/maneuver limiters, the control laws were shown to be adequate to prevent aircraft departure during aggressive air combat maneuvering.

An Overview of Controls and Flying Qualities Technology on the F/A-18 High Alpha Research Vehicle

NASA Technical Reports Server (NTRS)

Pahle, Joseph W.; Wichman, Keith D.; Foster, John V.; Bundick, W. Thomas

1996-01-01

The NASA F/A-18 High Alpha Research Vehicle (HARV) has been the flight test bed of a focused technology effort to significantly increase maneuvering capability at high angles of attack. Development and flight test of control law design methodologies, handling qualities metrics, performance guidelines, and flight evaluation maneuvers are described. The HARV has been modified to include two research control effectors, thrust vectoring, and actuated forebody strakes in order to provide increased control power at high angles of attack. A research flight control system has been used to provide a flexible, easily modified capability for high-angle-of-attack research controls. Different control law design techniques have been implemented and flight-tested, including eigenstructure assignment, variable gain output feedback, pseudo controls, and model-following. Extensive piloted simulation has been used to develop nonlinear performance guide-lines and handling qualities criteria for high angles of attack. This paper reviews the development and evaluation of technologies useful for high-angle-of-attack control. Design, development, and flight test of the research flight control system, control laws, flying qualities specifications, and flight test maneuvers are described. Flight test results are used to illustrate some of the lessons learned during flight test and handling qualities evaluations.

Adaptive Control in the Presence of Simultaneous Sensor Bias and Actuator Failures

NASA Technical Reports Server (NTRS)

Joshi, Suresh M.

2012-01-01

The problem of simultaneously accommodating unknown sensor biases and unknown actuator failures in uncertain systems is considered in a direct model reference adaptive control (MRAC) setting for state tracking using state feedback. Sensor biases and actuator faults may be present at the outset or may occur at unknown instants of time during operation. A modified MRAC law is proposed, which combines sensor bias estimation with control gain adaptation for accommodation of sensor biases and actuator failures. This control law is shown to provide signal boundedness in the resulting system. For the case when an external asymptotically stable sensor bias estimator is available, an MRAC law is developed to accomplish asymptotic state tracking and signal boundedness. For a special case wherein biases are only present in the rate measurements and bias-free position measurements are available, an MRAC law is developed using a model-independent bias estimator, and is shown to provide asymptotic state tracking with signal boundedness.

Value Iteration Adaptive Dynamic Programming for Optimal Control of Discrete-Time Nonlinear Systems.

PubMed

Wei, Qinglai; Liu, Derong; Lin, Hanquan

2016-03-01

In this paper, a value iteration adaptive dynamic programming (ADP) algorithm is developed to solve infinite horizon undiscounted optimal control problems for discrete-time nonlinear systems. The present value iteration ADP algorithm permits an arbitrary positive semi-definite function to initialize the algorithm. A novel convergence analysis is developed to guarantee that the iterative value function converges to the optimal performance index function. Initialized by different initial functions, it is proven that the iterative value function will be monotonically nonincreasing, monotonically nondecreasing, or nonmonotonic and will converge to the optimum. In this paper, for the first time, the admissibility properties of the iterative control laws are developed for value iteration algorithms. It is emphasized that new termination criteria are established to guarantee the effectiveness of the iterative control laws. Neural networks are used to approximate the iterative value function and compute the iterative control law, respectively, for facilitating the implementation of the iterative ADP algorithm. Finally, two simulation examples are given to illustrate the performance of the present method.

Inverse free steering law for small satellite attitude control and power tracking with VSCMGs

NASA Astrophysics Data System (ADS)

Malik, M. S. I.; Asghar, Sajjad

2014-01-01

Recent developments in integrated power and attitude control systems (IPACSs) for small satellite, has opened a new dimension to more complex and demanding space missions. This paper presents a new inverse free steering approach for integrated power and attitude control systems using variable-speed single gimbal control moment gyroscope. The proposed inverse free steering law computes the VSCMG steering commands (gimbal rates and wheel accelerations) such that error signal (difference in command and output) in feedback loop is driven to zero. H∞ norm optimization approach is employed to synthesize the static matrix elements of steering law for a static state of VSCMG. Later these matrix elements are suitably made dynamic in order for the adaptation. In order to improve the performance of proposed steering law while passing through a singular state of CMG cluster (no torque output), the matrix element of steering law is suitably modified. Therefore, this steering law is capable of escaping internal singularities and using the full momentum capacity of CMG cluster. Finally, two numerical examples for a satellite in a low earth orbit are simulated to test the proposed steering law.

Development of the L-1011 four-dimensional flight management system

NASA Technical Reports Server (NTRS)

Lee, H. P.; Leffler, M. F.

1984-01-01

The development of 4-D guidance and control algorithms for the L-1011 Flight Management System is described. Four-D Flight Management is a concept by which an aircraft's flight is optimized along the 3-D path within the constraints of today's ATC environment, while its arrival time is controlled to fit into the air traffic flow without incurring or causing delays. The methods developed herein were designed to be compatible with the time-based en route metering techniques that were recently developed by the Dallas/Fort Worth and Denver Air Route Traffic Control Centers. The ensuing development of the 4-D guidance algorithms, the necessary control laws and the operational procedures are discussed. Results of computer simulation evaluation of the guidance algorithms and control laws are presented, along with a description of the software development procedures utilized.

Model-independent position domain sliding mode control for contour tracking of robotic manipulator

NASA Astrophysics Data System (ADS)

Yue, W. H.; Pano, V.; Ouyang, P. R.; Hu, Y. Q.

2017-01-01

In this paper, a new position domain feedback type sliding mode control (PDC-SMC) law is proposed for contour tracking control of multi-DOF (degree of freedom) nonlinear robotic manipulators focusing on the improvement of contour tracking performances. One feature of the proposed control law is its model-independent control scheme that can avoid calculation of the feedforward part in a standard SMC. The new control law takes the advantages of the high contour tracking performance of PD type feedback position domain control (PDC) and the robustness of SMC. Stability analysis is performed using the Lyapunov stability theory, and simulation studies are conducted to verify the effectiveness of the developed PDC-SMC control system. In addition, the effects of control parameters of the SMC on system performances are studied.

Development of ADOCS controllers and control laws. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

Landis, Kenneth H.; Glusman, Steven I.

1985-01-01

The Advanced Cockpit Controls/Advanced Flight Control System (ACC/AFCS) study was conducted by the Boeing Vertol Company as part of the Army's Advanced Digital/Optical Control System (ADOCS) program. Specifically, the ACC/AFCS investigation was aimed at developing the flight control laws for the ADOCS demonstrator aircraft that will provide satisfactory handling qualities for an attack helicopter mission. The three major elements of design considered during the study are as follows: Pilot's integrated Side-Stick Controller (SSC) -- Number of axes controlled; force/displacement characteristics; ergonomic design. Stability and Control Augmentation System (SCAS)--Digital flight control laws for the various mission phases; SCAS mode switching logic. Pilot's Displays--For night/adverse weather conditions, the dynamics of the superimposed symbology presented to the pilot in a format similar to the Advanced Attack Helicopter (AAH) Pilot Night Vision System (PNVS) for each mission phase as a function of SCAS characteristics; display mode switching logic. Volume 1 is an Executive Summary of the study. Conclusions drawn from analysis of pilot rating data and commentary were used to formulate recommendations for the ADOCS demonstrator flight control system design. The ACC/AFCS simulation data also provide an extensive data base to aid the development of advanced flight control system design for future V/STOL aircraft.

Homography-based control scheme for mobile robots with nonholonomic and field-of-view constraints.

PubMed

López-Nicolás, Gonzalo; Gans, Nicholas R; Bhattacharya, Sourabh; Sagüés, Carlos; Guerrero, Josechu J; Hutchinson, Seth

2010-08-01

In this paper, we present a visual servo controller that effects optimal paths for a nonholonomic differential drive robot with field-of-view constraints imposed by the vision system. The control scheme relies on the computation of homographies between current and goal images, but unlike previous homography-based methods, it does not use the homography to compute estimates of pose parameters. Instead, the control laws are directly expressed in terms of individual entries in the homography matrix. In particular, we develop individual control laws for the three path classes that define the language of optimal paths: rotations, straight-line segments, and logarithmic spirals. These control laws, as well as the switching conditions that define how to sequence path segments, are defined in terms of the entries of homography matrices. The selection of the corresponding control law requires the homography decomposition before starting the navigation. We provide a controllability and stability analysis for our system and give experimental results.

Digital controllers for VTOL aircraft

NASA Technical Reports Server (NTRS)

Stengel, R. F.; Broussard, J. R.; Berry, P. W.

1976-01-01

Using linear-optimal estimation and control techniques, digital-adaptive control laws have been designed for a tandem-rotor helicopter which is equipped for fully automatic flight in terminal area operations. Two distinct discrete-time control laws are designed to interface with velocity-command and attitude-command guidance logic, and each incorporates proportional-integral compensation for non-zero-set-point regulation, as well as reduced-order Kalman filters for sensor blending and noise rejection. Adaptation to flight condition is achieved with a novel gain-scheduling method based on correlation and regression analysis. The linear-optimal design approach is found to be a valuable tool in the development of practical multivariable control laws for vehicles which evidence significant coupling and insufficient natural stability.

Flight Control System Development for the BURRO Autonomous UAV

NASA Technical Reports Server (NTRS)

Colbourne, Jason D.; Frost, Chad R.; Tischler, Mark B.; Ciolani, Luigi; Sahai, Ranjana; Tomoshofski, Chris; LaMontagne, Troy; Rutkowski, Michael (Technical Monitor)

2000-01-01

Developing autonomous flying vehicles has been a growing field in aeronautical research within the last decade and will continue into the next century. With concerns about safety, size, and cost of manned aircraft, several autonomous vehicle projects are currently being developed; uninhabited rotorcraft offer solutions to requirements for hover, vertical take-off and landing, as well as slung load transportation capabilities. The newness of the technology requires flight control engineers to question what design approaches, control law architectures, and performance criteria apply to control law development and handling quality evaluation. To help answer these questions, this paper documents the control law design process for Kaman Aerospace BURRO project. This paper will describe the approach taken to design control laws and develop math models which will be used to convert the manned K-MAX into the BURRO autonomous rotorcraft. With the ability of the K-MAX to lift its own weight (6000 lb) the load significantly affects the dynamics of the system; the paper addresses the additional design requirements for slung load autonomous flight. The approach taken in this design was to: 1) generate accurate math models of the K-MAX helicopter with and without slung loads, 2) select design specifications that would deliver good performance as well as satisfy mission criteria, and 3) develop and tune the control system architecture to meet the design specs and mission criteria. An accurate math model was desired for control system development. The Comprehensive Identification from Frequency Responses (CIFER(R)) software package was used to identify a linear math model for unloaded and loaded flight at hover, 50 kts, and 100 kts. The results of an eight degree-of-freedom CIFER(R)-identified linear model for the unloaded hover flight condition are presented herein, and the identification of the two-body slung-load configuration is in progress.

Fault Tolerance Analysis of L1 Adaptive Control System for Unmanned Aerial Vehicles

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Kiruthika

Trajectory tracking is a critical element for the better functionality of autonomous vehicles. The main objective of this research study was to implement and analyze L1 adaptive control laws for autonomous flight under normal and upset flight conditions. The West Virginia University (WVU) Unmanned Aerial Vehicle flight simulation environment was used for this purpose. A comparison study between the L1 adaptive controller and a baseline conventional controller, which relies on position, proportional, and integral compensation, has been performed for a reduced size jet aircraft, the WVU YF-22. Special attention was given to the performance of the proposed control laws in the presence of abnormal conditions. The abnormal conditions considered are locked actuators (stabilator, aileron, and rudder) and excessive turbulence. Several levels of abnormal condition severity have been considered. The performance of the control laws was assessed over different-shape commanded trajectories. A set of comprehensive evaluation metrics was defined and used to analyze the performance of autonomous flight control laws in terms of control activity and trajectory tracking errors. The developed L1 adaptive control laws are supported by theoretical stability guarantees. The simulation results show that L1 adaptive output feedback controller achieves better trajectory tracking with lower level of control actuation as compared to the baseline linear controller under nominal and abnormal conditions.

An optimal controller for an electric ventricular-assist device: theory, implementation, and testing.

PubMed

Klute, G K; Tasch, U; Geselowitz, D B

1992-04-01

This paper addresses the development and testing of an optimal position feedback controller for the Penn State electric ventricular-assist device (EVAD). The control law is designed to minimize the expected value of the EVAD's power consumption for a targeted patient population. The closed-loop control law is implemented on an Intel 8096 microprocessor and in vitro test runs show that this controller improves the EVAD's efficiency by 15-21%, when compared with the performance of the currently used feedforward control scheme.

Feedback laws for fuel minimization for transport aircraft

NASA Technical Reports Server (NTRS)

Price, D. B.; Gracey, C.

1984-01-01

The Theoretical Mechanics Branch has as one of its long-range goals to work toward solving real-time trajectory optimization problems on board an aircraft. This is a generic problem that has application to all aspects of aviation from general aviation through commercial to military. Overall interest is in the generic problem, but specific problems to achieve concrete results are examined. The problem is to develop control laws that generate approximately optimal trajectories with respect to some criteria such as minimum time, minimum fuel, or some combination of the two. These laws must be simple enough to be implemented on a computer that is flown on board an aircraft, which implies a major simplification from the two point boundary value problem generated by a standard trajectory optimization problem. In addition, the control laws allow for changes in end conditions during the flight, and changes in weather along a planned flight path. Therefore, a feedback control law that generates commands based on the current state rather than a precomputed open-loop control law is desired. This requirement, along with the need for order reduction, argues for the application of singular perturbation techniques.

Adaptive Attitude Control of the Crew Launch Vehicle

NASA Technical Reports Server (NTRS)

Muse, Jonathan

2010-01-01

An H(sub infinity)-NMA architecture for the Crew Launch Vehicle was developed in a state feedback setting. The minimal complexity adaptive law was shown to improve base line performance relative to a performance metric based on Crew Launch Vehicle design requirements for all most all of the Worst-on-Worst dispersion cases. The adaptive law was able to maintain stability for some dispersions that are unstable with the nominal control law. Due to the nature of the H(sub infinity)-NMA architecture, the augmented adaptive control signal has low bandwidth which is a great benefit for a manned launch vehicle.

Sliding Mode Control of Dynamic Voltage Restorer by Using a New Adaptive Reaching Law

NASA Astrophysics Data System (ADS)

Pandey, Achala; Agrawal, Rekha; Mandloi, Ravindra S.; Sarkar, Biswaroop

2017-12-01

This paper presents a new kind of adaptive reaching law for sliding mode control of Dynamic Voltage Restorer (DVR). Such an adaptive reaching law follows under-damped sinusoidal nature that causes the initial state to reach the sliding regime in extremely less time with negligible chattering. Moreover, it is robust in the sense the trajectory does not deviate from the sliding surface. This new approach is developed and successfully applied to DVR. The simulation results are presented that show its robustness.

Develop minimum thrustor control laws and select orbits for a geodesy drag-free satellite

NASA Technical Reports Server (NTRS)

Breakwell, J. V.; Debra, D. B.

1974-01-01

The original motivation for studying control laws for pulse plasma systems was based on the improved life characteristics possible with pulse plasma jets. These pulse plasma units are relatively massive compared with cold gas thrustors. As a result, therefore, significant mass savings can be achieved by minimizing the the number of thrustors. The control laws, therefore, were developed for thrust available from two thrustors only. In a spinning satellite, these thrustors are sufficient to completely control the vehicle as long as the spin rate is sufficiently high for a given level of external disturbance. The thrustors are canted so that a component of each is along the plus and minus spin axis. The other component of each thrustor acts in the radial direction. It is sufficient to analyze the behavior in the plane of spin assuming a single thrustor.

A comparison of CMG steering laws for High Energy Astronomy Observatories (HEAOs)

NASA Technical Reports Server (NTRS)

Davis, B. G.

1972-01-01

A comparison of six selected control moment gyro steering laws for use on the HEAO spacecraft is reported. Basic equations are developed to project the momentum and torque of four skewed, single gimbal CMGs into vehicle coordinates. In response to the spacecraft attitude error signal, six algorithms are derived for controlling the CMG gimbal movements. HEAO performance data are obtained using each steering law and compared on the basis of such factors as accuracy, complexity, singularities, gyro hang-up and failure adaption. Moreover, each law is simulated with and without a magnetic momentum management system. The performance of any steering law is enhanced by the magnetic system. Without magnetics, the gimbal angles get large and there are significant differences in steering law performances due to cross coupling and nonlinearities. The performance of the pseudo inverse law is recommended for HEAO.

Towards physics of neural processes and behavior

PubMed Central

Latash, Mark L.

2016-01-01

Behavior of biological systems is based on basic physical laws, common across inanimate and living systems, and currently unknown physical laws that are specific for living systems. Living systems are able to unite basic laws of physics into chains and clusters leading to new stable and pervasive relations among variables (new physical laws) involving new parameters and to modify these parameters in a purposeful way. Examples of such laws are presented starting from the tonic stretch reflex. Further, the idea of control with referent coordinates is formulated and merged with the idea of hierarchical control and the principle of abundance. The notion of controlled stability of behaviors is linked to the idea of structured variability, which is a common feature across living systems and actions. The explanatory and predictive power of this approach is illustrated with respect to the control of both intentional and unintentional movements, the phenomena of equifinality and its violations, preparation to quick actions, development of motor skills, changes with aging and neurological disorders, and perception. PMID:27497717

Fault tolerant control laws

NASA Technical Reports Server (NTRS)

Ly, U. L.; Ho, J. K.

1986-01-01

A systematic procedure for the synthesis of fault tolerant control laws to actuator failure has been presented. Two design methods were used to synthesize fault tolerant controllers: the conventional LQ design method and a direct feedback controller design method SANDY. The latter method is used primarily to streamline the full-state Q feedback design into a practical implementable output feedback controller structure. To achieve robustness to control actuator failure, the redundant surfaces are properly balanced according to their control effectiveness. A simple gain schedule based on the landing gear up/down logic involving only three gains was developed to handle three design flight conditions: Mach .25 and Mach .60 at 5000 ft and Mach .90 at 20,000 ft. The fault tolerant control law developed in this study provides good stability augmentation and performance for the relaxed static stability aircraft. The augmented aircraft responses are found to be invariant to the presence of a failure. Furthermore, single-loop stability margins of +6 dB in gain and +30 deg in phase were achieved along with -40 dB/decade rolloff at high frequency.

Flight Test of the F/A-18 Active Aeroelastic Wing Airplane

NASA Technical Reports Server (NTRS)

Clarke, Robert; Allen, Michael J.; Dibley, Ryan P.; Gera, Joseph; Hodgkinson, John

2005-01-01

Successful flight-testing of the Active Aeroelastic Wing airplane was completed in March 2005. This program, which started in 1996, was a joint activity sponsored by NASA, Air Force Research Laboratory, and industry contractors. The test program contained two flight test phases conducted in early 2003 and early 2005. During the first phase of flight test, aerodynamic models and load models of the wing control surfaces and wing structure were developed. Design teams built new research control laws for the Active Aeroelastic Wing airplane using these flight-validated models; and throughout the final phase of flight test, these new control laws were demonstrated. The control laws were designed to optimize strategies for moving the wing control surfaces to maximize roll rates in the transonic and supersonic flight regimes. Control surface hinge moments and wing loads were constrained to remain within hydraulic and load limits. This paper describes briefly the flight control system architecture as well as the design approach used by Active Aeroelastic Wing project engineers to develop flight control system gains. Additionally, this paper presents flight test techniques and comparison between flight test results and predictions.

Integrated Control Using the SOFFT Control Structure

NASA Technical Reports Server (NTRS)

Halyo, Nesim

1996-01-01

The need for integrated/constrained control systems has become clearer as advanced aircraft introduced new coupled subsystems such as new propulsion subsystems with thrust vectoring and new aerodynamic designs. In this study, we develop an integrated control design methodology which accomodates constraints among subsystem variables while using the Stochastic Optimal Feedforward/Feedback Control Technique (SOFFT) thus maintaining all the advantages of the SOFFT approach. The Integrated SOFFT Control methodology uses a centralized feedforward control and a constrained feedback control law. The control thus takes advantage of the known coupling among the subsystems while maintaining the identity of subsystems for validation purposes and the simplicity of the feedback law to understand the system response in complicated nonlinear scenarios. The Variable-Gain Output Feedback Control methodology (including constant gain output feedback) is extended to accommodate equality constraints. A gain computation algorithm is developed. The designer can set the cross-gains between two variables or subsystems to zero or another value and optimize the remaining gains subject to the constraint. An integrated control law is designed for a modified F-15 SMTD aircraft model with coupled airframe and propulsion subsystems using the Integrated SOFFT Control methodology to produce a set of desired flying qualities.

Power Policy 21 Century: Growth of the Population, Economics, Ecology and Entropy

NASA Astrophysics Data System (ADS)

Prisniakov, Vladimir

2002-01-01

but energy consumed by a man will be a limiting factor. Obtained values of changing in the quantity of population as well as of the consumed fuel quantity in the 21 century have been analysed. The period was defined (2005-2085) when energy hungry is possible due to a higher rate of a human reproduction comparing to the rates of energy consumption. From new position, the laws of the Earth population growth are analysed, based on the equality of the quantity of dying people to the quantity of those bornyears ago, whereis life expectancy. investigated on the base of Second law of thermodynamics. The equation of money exchange dY = (V/p)dM in going from quantity real GNP Y to consumption fuel equivalent E=pd Y takes the form: dE =VdM. General correlation between S and M is proposed: dS = (HV/T)dM, where H is enthalpy; V is velocity of money; T is temperature; p is total prices,is capacity of manufacture resources. This equation shows direction of the spontaneity development of economical processes as part of general law Universe. The original equation of removing from information to matter equation enables to control output natural resources by economic laws, and to control of activities for the restoration wrecked nature.This equation shows the direction of the spontaneity development of economical processes as part of a general Universal law. into account value of expenditure on ecology as part of price and overstated price indexes. The criterions allow to discover numerical values of a stock of money, ecology part of price, velocity of money, value of the taxes, which ensure sustainable development. These equations enable to control output natural resources by economic laws, and to control activities for the restoration of wrecked nature.

Bi-Objective Optimal Control Modification Adaptive Control for Systems with Input Uncertainty

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.

2012-01-01

This paper presents a new model-reference adaptive control method based on a bi-objective optimal control formulation for systems with input uncertainty. A parallel predictor model is constructed to relate the predictor error to the estimation error of the control effectiveness matrix. In this work, we develop an optimal control modification adaptive control approach that seeks to minimize a bi-objective linear quadratic cost function of both the tracking error norm and predictor error norm simultaneously. The resulting adaptive laws for the parametric uncertainty and control effectiveness uncertainty are dependent on both the tracking error and predictor error, while the adaptive laws for the feedback gain and command feedforward gain are only dependent on the tracking error. The optimal control modification term provides robustness to the adaptive laws naturally from the optimal control framework. Simulations demonstrate the effectiveness of the proposed adaptive control approach.

Missile Guidance Law Based on Robust Model Predictive Control Using Neural-Network Optimization.

PubMed

Li, Zhijun; Xia, Yuanqing; Su, Chun-Yi; Deng, Jun; Fu, Jun; He, Wei

2015-08-01

In this brief, the utilization of robust model-based predictive control is investigated for the problem of missile interception. Treating the target acceleration as a bounded disturbance, novel guidance law using model predictive control is developed by incorporating missile inside constraints. The combined model predictive approach could be transformed as a constrained quadratic programming (QP) problem, which may be solved using a linear variational inequality-based primal-dual neural network over a finite receding horizon. Online solutions to multiple parametric QP problems are used so that constrained optimal control decisions can be made in real time. Simulation studies are conducted to illustrate the effectiveness and performance of the proposed guidance control law for missile interception.

Law of Mass Communications: Freedom and Control of Print and Broadcast Media. Third Edition.

ERIC Educational Resources Information Center

Nelson, Harold L.; Teeter, Dwight L., Jr.

This book is divided into three major sections: principles and development of freedom of expression, rights in conflict with free expression, and communications law and the public interest. Specific areas covered in the two chapters of the first section are freedom and control and a historical background of freedom of expression. The second…

Experimental demonstration of the control of flexible structures

NASA Technical Reports Server (NTRS)

Schaechter, D. B.; Eldred, D. B.

1984-01-01

The Large Space Structure Technology Flexible Beam Experiment employs a pinned-free flexible beam to demonstrate such required methods as dynamic and adaptive control, as well as various control law design approaches and hardware requirements. An attempt is made to define the mechanization difficulties that may inhere in flexible structures. Attention is presently given to analytical work performed in support of the test facility's development, the final design's specifications, the control laws' synthesis, and experimental results obtained.

Addressing Control Research Issues Leading to Piloted Simulations in Support of the IFCS F-15

NASA Technical Reports Server (NTRS)

Napolitano, Marcello; Perhinschi, Mario; Campa, Giampiero; Seanor, Brad

2004-01-01

This report summarizes the research effort by a team of researchers at West Virginia University in support of the NASA Intelligent Flight Control System (IFCS) F-15 program. In particular, WVU researchers assisted NASA Dryden researchers in the following technical tasks leading to piloted simulation of the 'Gen_2' IFCS control laws. Task #1- Performance comparison of different neural network (NN) augmentation for the Dynamic Inversion (DI) -based VCAS 'Gen_2' control laws. Task #2- Development of safety monitor criteria for transition to research control laws with and without failure during flight test. Task #3- Fine-tuning of the 'Gen_2' control laws for cross-coupling reduction at post-failure conditions. Matlab/Simulink-based simulation codes were provided to the technical monitor on a regular basis throughout the duration of the project. Additional deliverables for the project were Power Point-based slides prepared for different project meetings. This document provides a description of the methodology and discusses the general conclusions from the simulation results.

Development of ADOCS controllers and control laws. Volume 3: Simulation results and recommendations

NASA Technical Reports Server (NTRS)

Landis, Kenneth H.; Glusman, Steven I.

1985-01-01

The Advanced Cockpit Controls/Advanced Flight Control System (ACC/AFCS) study was conducted by the Boeing Vertol Company as part of the Army's Advanced Digital/Optical Control System (ADOCS) program. Specifically, the ACC/AFCS investigation was aimed at developing the flight control laws for the ADOCS demonstator aircraft which will provide satisfactory handling qualities for an attack helicopter mission. The three major elements of design considered are as follows: Pilot's integrated Side-Stick Controller (SSC) -- Number of axes controlled; force/displacement characteristics; ergonomic design. Stability and Control Augmentation System (SCAS)--Digital flight control laws for the various mission phases; SCAS mode switching logic. Pilot's Displays--For night/adverse weather conditions, the dynamics of the superimposed symbology presented to the pilot in a format similar to the Advanced Attack Helicopter (AAH) Pilot Night Vision System (PNVS) for each mission phase is a function of SCAS characteristics; display mode switching logic. Results of the five piloted simulations conducted at the Boeing Vertol and NASA-Ames simulation facilities are presented in Volume 3. Conclusions drawn from analysis of pilot rating data and commentary were used to formulate recommendations for the ADOCS demonstrator flight control system design. The ACC/AFCS simulation data also provide an extensive data base to aid the development of advanced flight control system design for future V/STOL aircraft.

Heuristic approach to the development of ratings and tactics applicable to the one-on-one aerial combat (dogfight) encounter

NASA Technical Reports Server (NTRS)

Hague, D. S.

1977-01-01

Computer simulations of the one-on-one aerial combat encounter are generated under the control of specified guidance laws. Given an initial state, the vehicle and atmospheric characteristics, and the guidance laws, the aerial combat encounter is simulated by forward integration of the two vehicles' motions. The development of a combat guidance law which converts positional advantage into an improved firing opportunity is reported. A combination of lag, line of sight, and lead pursuit steering paths are followed in the guidance law. The law is based on steering error, target angle-off and the relative velocities. It readily is automated either as an onboard aid to manned aircraft pilots or as a combat guidance law for unmanned vehicles.

Design and experimental validation of linear and nonlinear vehicle steering control strategies

NASA Astrophysics Data System (ADS)

Menhour, Lghani; Lechner, Daniel; Charara, Ali

2012-06-01

This paper proposes the design of three control laws dedicated to vehicle steering control, two based on robust linear control strategies and one based on nonlinear control strategies, and presents a comparison between them. The two robust linear control laws (indirect and direct methods) are built around M linear bicycle models, each of these control laws is composed of two M proportional integral derivative (PID) controllers: one M PID controller to control the lateral deviation and the other M PID controller to control the vehicle yaw angle. The indirect control law method is designed using an oscillation method and a nonlinear optimisation subject to H ∞ constraint. The direct control law method is designed using a linear matrix inequality optimisation in order to achieve H ∞ performances. The nonlinear control method used for the correction of the lateral deviation is based on a continuous first-order sliding-mode controller. The different methods are designed using a linear bicycle vehicle model with variant parameters, but the aim is to simulate the nonlinear vehicle behaviour under high dynamic demands with a four-wheel vehicle model. These steering vehicle controls are validated experimentally using the data acquired using a laboratory vehicle, Peugeot 307, developed by National Institute for Transport and Safety Research - Department of Accident Mechanism Analysis Laboratory's (INRETS-MA) and their performance results are compared. Moreover, an unknown input sliding-mode observer is introduced to estimate the road bank angle.

Explaining the emergence of euthanasia law in the Netherlands: how the sociology of law can help the sociology of bioethics.

PubMed

Weyers, Heleen

2006-09-01

The debate over the legalisation of voluntary euthanasia is most often seen to be the result of three changes in society: individualisation, diminished taboos concerning death and changes in the balance of power in medicine. The fact that these changes occurred in many western countries but led to legalisation in only a few makes this claim problematic. I examine whether socio-legal propositions, with respect to the emergence of laws which focus on social control, offer a better approach to understanding the development of rules allowing and governing euthanasia. After a short sketch of the history of the Dutch law regulating euthanasia, I discuss these three societal changes in the light of shifts in the social control of medical behaviour that shortens life. I show that the Dutch relaxation of the prohibition of euthanasia goes together with new forms of social control: doctors' self control is complemented with second-party control (by patients), professional third-party control and governmental control. My work calls attention to the fact that bioethics is part of larger systems of social control.

Advanced AFCS developments on the XV-15 tilt rotor research aircraft. [Automatic Flight Control System

NASA Technical Reports Server (NTRS)

Churchill, G. B.; Gerdes, R. M.

1984-01-01

The design criteria and control and handling qualities of the Automatic Flight Control System (AFCS), developed in the framework of the XV-15 tilt-rotor research aircraft, are evaluated, differentiating between the stability and control criteria. A technically aggressive SCAS control law was implemented, demonstrating that significant benefits accrue when stability criteria are separated from design criteria; the design analyses for application of the control law are presented, and the limit bandwidth for stabilization in hovering flight is shown to be defined by rotor or control lag functions. Flight tests of the aircraft resulted in a rating of 3 on the Cooper-Harper scale; a possibility of achieving a rating of 2 is expected if the system is applied to the yaw and heave control modes.

On-line analysis capabilities developed to support the AFW wind-tunnel tests

NASA Technical Reports Server (NTRS)

Wieseman, Carol D.; Hoadley, Sherwood T.; Mcgraw, Sandra M.

1992-01-01

A variety of on-line analysis tools were developed to support two active flexible wing (AFW) wind-tunnel tests. These tools were developed to verify control law execution, to satisfy analysis requirements of the control law designers, to provide measures of system stability in a real-time environment, and to provide project managers with a quantitative measure of controller performance. Descriptions and purposes of the developed capabilities are presented along with examples. Procedures for saving and transferring data for near real-time analysis, and descriptions of the corresponding data interface programs are also presented. The on-line analysis tools worked well before, during, and after the wind tunnel test and proved to be a vital and important part of the entire test effort.

Advances in Adaptive Control Methods

NASA Technical Reports Server (NTRS)

Nguyen, Nhan

2009-01-01

This poster presentation describes recent advances in adaptive control technology developed by NASA. Optimal Control Modification is a novel adaptive law that can improve performance and robustness of adaptive control systems. A new technique has been developed to provide an analytical method for computing time delay stability margin for adaptive control systems.

Formulation and experimental evaluation of closed-form control laws for the rapid maneuvering of reactor neutronic power

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernard, J.A.

1989-09-01

This report describes both the theoretical development and the experimental evaluation of a novel, robust methodology for the time-optimal adjustment of a reactor's neutronic power under conditions of closed-loop digital control. Central to the approach are the MIT-SNL Period-Generated Minimum Time Control Laws' which determine the rate at which reactivity should be changed in order to cause a reactor's neutronic power to conform to a specified trajectory. Using these laws, reactor power can be safely raised by five to seven orders of magnitude in a few seconds. The MIT-SNL laws were developed to facilitate rapid increases of neutronic power onmore » spacecraft reactors operating in an SDI environment. However, these laws are generic and have other applications including the rapid recovery of research and test reactors subsequent to an unanticipated shutdown, power increases following the achievement of criticality on commercial reactors, power adjustments on commercial reactors so as to minimize thermal stress, and automated startups. The work reported here was performed by the Massachusetts Institute of Technology under contract to the Sandia National Laboratories. Support was also provided by the US Department of Energy's Division of University and Industry Programs. The work described in this report is significant in that a novel solution to the problem of time-optimal control of neutronic power was identified, in that a rigorous description of a reactor's dynamics was derived in that the rate of change of reactivity was recognized as the proper control signal, and in that extensive experimental trials were conducted of these newly developed concepts on actual nuclear reactors. 43 refs., 118 figs., 11 tabs.« less

Equilibrium properties of the Skylab CMG rotation law

NASA Technical Reports Server (NTRS)

Elrod, B. D.; Anderson, G. M.

1972-01-01

The equilibrium properties of the control moment gyroscopes of the Skylab are discussed. A rotation law is developed to produce gimbal rates which distribute the angular momentum contributions among the control moment gyroscopes to avoid gimbal stop encounters. The implications for gimbal angle management under various angular momentum situations are described. Conditions were obtained for the existence of equilibria and corresponding stability properties.

Development of guidance laws for a variable-speed missile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gazit, R.; Gutman, S.

1991-05-01

The most used guidance law for short-range homing missiles is proportional navigation (PN). In PN, the acceleration command is proportional to the line-of-sight (LOS) angular velocity. Indeed, if a missile and a target move on a collision course with constant speeds, the LOS rate is zero. The speed of a highly maneuverable modern missile varies considerably during flight. The performance of PN is far from being satisfactory in that case. In this article the collision course for a variable-speed missile is analyzed and a guidance law that steers the heading of the missile to the collision course is defined. Guidancemore » laws based on optimal control and differential game formulations are developed, and note that both optimal laws coincide with the Guidance to Collision law at impact. The performance improvement of the missile using the new guidance law as compared to PN is demonstrated. 19 refs.« less

A stochastic optimal feedforward and feedback control methodology for superagility

NASA Technical Reports Server (NTRS)

Halyo, Nesim; Direskeneli, Haldun; Taylor, Deborah B.

1992-01-01

A new control design methodology is developed: Stochastic Optimal Feedforward and Feedback Technology (SOFFT). Traditional design techniques optimize a single cost function (which expresses the design objectives) to obtain both the feedforward and feedback control laws. This approach places conflicting demands on the control law such as fast tracking versus noise atttenuation/disturbance rejection. In the SOFFT approach, two cost functions are defined. The feedforward control law is designed to optimize one cost function, the feedback optimizes the other. By separating the design objectives and decoupling the feedforward and feedback design processes, both objectives can be achieved fully. A new measure of command tracking performance, Z-plots, is also developed. By analyzing these plots at off-nominal conditions, the sensitivity or robustness of the system in tracking commands can be predicted. Z-plots provide an important tool for designing robust control systems. The Variable-Gain SOFFT methodology was used to design a flight control system for the F/A-18 aircraft. It is shown that SOFFT can be used to expand the operating regime and provide greater performance (flying/handling qualities) throughout the extended flight regime. This work was performed under the NASA SBIR program. ICS plans to market the software developed as a new module in its commercial CACSD software package: ACET.

A method to stabilize linear systems using eigenvalue gradient information

NASA Technical Reports Server (NTRS)

Wieseman, C. D.

1985-01-01

Formal optimization methods and eigenvalue gradient information are used to develop a stabilizing control law for a closed loop linear system that is initially unstable. The method was originally formulated by using direct, constrained optimization methods with the constraints being the real parts of the eigenvalues. However, because of problems in trying to achieve stabilizing control laws, the problem was reformulated to be solved differently. The method described uses the Davidon-Fletcher-Powell minimization technique to solve an indirect, constrained minimization problem in which the performance index is the Kreisselmeier-Steinhauser function of the real parts of all the eigenvalues. The method is applied successfully to solve two different problems: the determination of a fourth-order control law stabilizes a single-input single-output active flutter suppression system and the determination of a second-order control law for a multi-input multi-output lateral-directional flight control system. Various sets of design variables and initial starting points were chosen to show the robustness of the method.

The dynamics and control of large flexible space structures, 6

NASA Technical Reports Server (NTRS)

Bainum, P. M.

1983-01-01

The controls analysis based on a truncated finite element model of the 122m. Hoop/Column Antenna System focuses on an analysis of the controllability as well as the synthesis of control laws. Graph theoretic techniques are employed to consider controllability for different combinations of number and locations of actuators. Control law synthesis is based on an application of the linear regulator theory as well as pole placement techniques. Placement of an actuator on the hoop can result in a noticeable improvement in the transient characteristics. The problem of orientation and shape control of an orbiting flexible beam, previously examined, is now extended to include the influence of solar radiation environmental forces. For extremely flexible thin structures modification of control laws may be required and techniques for accomplishing this are explained. Effects of environmental torques are also included in previously developed models of orbiting flexible thin platforms.

Direct adaptive robust tracking control for 6 DOF industrial robot with enhanced accuracy.

PubMed

Yin, Xiuxing; Pan, Li

2018-01-01

A direct adaptive robust tracking control is proposed for trajectory tracking of 6 DOF industrial robot in the presence of parametric uncertainties, external disturbances and uncertain nonlinearities. The controller is designed based on the dynamic characteristics in the working space of the end-effector of the 6 DOF robot. The controller includes robust control term and model compensation term that is developed directly based on the input reference or desired motion trajectory. A projection-type parametric adaptation law is also designed to compensate for parametric estimation errors for the adaptive robust control. The feasibility and effectiveness of the proposed direct adaptive robust control law and the associated projection-type parametric adaptation law have been comparatively evaluated based on two 6 DOF industrial robots. The test results demonstrate that the proposed control can be employed to better maintain the desired trajectory tracking even in the presence of large parametric uncertainties and external disturbances as compared with PD controller and nonlinear controller. The parametric estimates also eventually converge to the real values along with the convergence of tracking errors, which further validate the effectiveness of the proposed parametric adaption law. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Global synchronization of memristive neural networks subject to random disturbances via distributed pinning control.

PubMed

Guo, Zhenyuan; Yang, Shaofu; Wang, Jun

2016-12-01

This paper presents theoretical results on global exponential synchronization of multiple memristive neural networks in the presence of external noise by means of two types of distributed pinning control. The multiple memristive neural networks are coupled in a general structure via a nonlinear function, which consists of a linear diffusive term and a discontinuous sign term. A pinning impulsive control law is introduced in the coupled system to synchronize all neural networks. Sufficient conditions are derived for ascertaining global exponential synchronization in mean square. In addition, a pinning adaptive control law is developed to achieve global exponential synchronization in mean square. Both pinning control laws utilize only partial state information received from the neighborhood of the controlled neural network. Simulation results are presented to substantiate the theoretical results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Towards physics of neural processes and behavior.

PubMed

Latash, Mark L

2016-10-01

Behavior of biological systems is based on basic physical laws, common across inanimate and living systems, and currently unknown physical laws that are specific for living systems. Living systems are able to unite basic laws of physics into chains and clusters leading to new stable and pervasive relations among variables (new physical laws) involving new parameters and to modify these parameters in a purposeful way. Examples of such laws are presented starting from the tonic stretch reflex. Further, the idea of control with referent coordinates is formulated and merged with the idea of hierarchical control and the principle of abundance. The notion of controlled stability of behaviors is linked to the idea of structured variability, which is a common feature across living systems and actions. The explanatory and predictive power of this approach is illustrated with respect to the control of both intentional and unintentional movements, the phenomena of equifinality and its violations, preparation to quick actions, development of motor skills, changes with aging and neurological disorders, and perception. Copyright © 2016 Elsevier Ltd. All rights reserved.

Minimal complexity control law synthesis

NASA Technical Reports Server (NTRS)

Bernstein, Dennis S.; Haddad, Wassim M.; Nett, Carl N.

1989-01-01

A paradigm for control law design for modern engineering systems is proposed: Minimize control law complexity subject to the achievement of a specified accuracy in the face of a specified level of uncertainty. Correspondingly, the overall goal is to make progress towards the development of a control law design methodology which supports this paradigm. Researchers achieve this goal by developing a general theory of optimal constrained-structure dynamic output feedback compensation, where here constrained-structure means that the dynamic-structure (e.g., dynamic order, pole locations, zero locations, etc.) of the output feedback compensation is constrained in some way. By applying this theory in an innovative fashion, where here the indicated iteration occurs over the choice of the compensator dynamic-structure, the paradigm stated above can, in principle, be realized. The optimal constrained-structure dynamic output feedback problem is formulated in general terms. An elegant method for reducing optimal constrained-structure dynamic output feedback problems to optimal static output feedback problems is then developed. This reduction procedure makes use of star products, linear fractional transformations, and linear fractional decompositions, and yields as a byproduct a complete characterization of the class of optimal constrained-structure dynamic output feedback problems which can be reduced to optimal static output feedback problems. Issues such as operational/physical constraints, operating-point variations, and processor throughput/memory limitations are considered, and it is shown how anti-windup/bumpless transfer, gain-scheduling, and digital processor implementation can be facilitated by constraining the controller dynamic-structure in an appropriate fashion.

Robust adaptive precision motion control of hydraulic actuators with valve dead-zone compensation.

PubMed

Deng, Wenxiang; Yao, Jianyong; Ma, Dawei

2017-09-01

This paper addresses the high performance motion control of hydraulic actuators with parametric uncertainties, unmodeled disturbances and unknown valve dead-zone. By constructing a smooth dead-zone inverse, a robust adaptive controller is proposed via backstepping method, in which adaptive law is synthesized to deal with parametric uncertainties and a continuous nonlinear robust control law to suppress unmodeled disturbances. Since the unknown dead-zone parameters can be estimated by adaptive law and then the effect of dead-zone can be compensated effectively via inverse operation, improved tracking performance can be expected. In addition, the disturbance upper bounds can also be updated online by adaptive laws, which increases the controller operability in practice. The Lyapunov based stability analysis shows that excellent asymptotic output tracking with zero steady-state error can be achieved by the developed controller even in the presence of unmodeled disturbance and unknown valve dead-zone. Finally, the proposed control strategy is experimentally tested on a servovalve controlled hydraulic actuation system subjected to an artificial valve dead-zone. Comparative experimental results are obtained to illustrate the effectiveness of the proposed control scheme. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Passing a smoke-free law in a pro-tobacco culture: a multiple streams approach.

PubMed

Greathouse, Lisa W; Hahn, Ellen J; Okoli, Chizimuzo T C; Warnick, Todd A; Riker, Carol A

2005-08-01

This article describes a case study of the policy development and political decision-making process involved in the enactment of Lexington, Kentucky's smoke-free law. The multiple streams framework is used to analyze the development of the law in a seemingly unlikely and challenging political environment. Proponents developed a dissemination research plan targeted at policy makers and the public to demonstrate the need for a comprehensive law. The existence of a strong coalition of health care providers and health care systems including the board of health, as well as long-standing tobacco control expertise and a strong legal team, were essential ingredients for success. A deliberate strategy to expose the tobacco industry was effective in preparing policy makers for the opponents' policy arguments. As expected, a hospitality industry association was formed to oppose the ordinance, resulting in a legal challenge that delayed enactment of the law.

Helicopter mathematical models and control law development for handling qualities research

NASA Technical Reports Server (NTRS)

Chen, Robert T. N.; Lebacqz, J. Victor; Aiken, Edwin W.; Tischler, Mark B.

1988-01-01

Progress made in joint NASA/Army research concerning rotorcraft flight-dynamics modeling, design methodologies for rotorcraft flight-control laws, and rotorcraft parameter identification is reviewed. Research into these interactive disciplines is needed to develop the analytical tools necessary to conduct flying qualities investigations using both the ground-based and in-flight simulators, and to permit an efficient means of performing flight test evaluation of rotorcraft flying qualities for specification compliance. The need for the research is particularly acute for rotorcraft because of their mathematical complexity, high order dynamic characteristics, and demanding mission requirements. The research in rotorcraft flight-dynamics modeling is pursued along two general directions: generic nonlinear models and nonlinear models for specific rotorcraft. In addition, linear models are generated that extend their utilization from 1-g flight to high-g maneuvers and expand their frequency range of validity for the design analysis of high-gain flight control systems. A variety of methods ranging from classical frequency-domain approaches to modern time-domain control methodology that are used in the design of rotorcraft flight control laws is reviewed. Also reviewed is a study conducted to investigate the design details associated with high-gain, digital flight control systems for combat rotorcraft. Parameter identification techniques developed for rotorcraft applications are reviewed.

Low-thrust orbit transfer optimization with refined Q-law and multi-objective genetic algorithm

NASA Technical Reports Server (NTRS)

Lee, Seungwon; Petropoulos, Anastassios E.; von Allmen, Paul

2005-01-01

An optimization method for low-thrust orbit transfers around a central body is developed using the Q-law and a multi-objective genetic algorithm. in the hybrid method, the Q-law generates candidate orbit transfers, and the multi-objective genetic algorithm optimizes the Q-law control parameters in order to simultaneously minimize both the consumed propellant mass and flight time of the orbit tranfer. This paper addresses the problem of finding optimal orbit transfers for low-thrust spacecraft.

Impact of a comprehensive law on the prevalence of tobacco consumption in Spain: evaluation of different scenarios.

PubMed

Raña, P; Pérez-Ríos, M; Santiago-Pérez, M I; Crujeiras, R M

2016-09-01

Since 2011, smoking legislation was hardened in Spain, banning tobacco consumption in all hospitality venues. Law 42/2010 was the first comprehensive tobacco control policy enacted in Spain. The aim of this paper is to evaluate the effect that this intervention has had in reducing the prevalence of tobacco consumption, setting up three scenarios on the basis of different theoretical levels of effect of the law. A predictive model based on Markov Chains was developed to distinguish the effect of tobacco control policies in different scenarios. The model developed uses population, smoking rates and smoking characteristics from a non-transmissible disease surveillance system developed in Galicia (namely SICRI). Results show that tobacco control policies hardly affect the predicted trend in a temporal frame of 10 years, with relative reduction in the predicted male smoking prevalence of 20.4% with no intervention, reaching a reduction of 26.1% under the maximum effect of the policies. In the global population the effects of the law in the predicted prevalence have been barely perceived. For people under 25 years of age, interventions have had an important and positive effect, which proves that policies affecting this age group should be hardened. Copyright © 2016 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Design Of Combined Stochastic Feedforward/Feedback Control

NASA Technical Reports Server (NTRS)

Halyo, Nesim

1989-01-01

Methodology accommodates variety of control structures and design techniques. In methodology for combined stochastic feedforward/feedback control, main objectives of feedforward and feedback control laws seen clearly. Inclusion of error-integral feedback, dynamic compensation, rate-command control structure, and like integral element of methodology. Another advantage of methodology flexibility to develop variety of techniques for design of feedback control with arbitrary structures to obtain feedback controller: includes stochastic output feedback, multiconfiguration control, decentralized control, or frequency and classical control methods. Control modes of system include capture and tracking of localizer and glideslope, crab, decrab, and flare. By use of recommended incremental implementation, control laws simulated on digital computer and connected with nonlinear digital simulation of aircraft and its systems.

Development and Testing of Control Laws for the Active Aeroelastic Wing Program

NASA Technical Reports Server (NTRS)

Dibley, Ryan P.; Allen, Michael J.; Clarke, Robert; Gera, Joseph; Hodgkinson, John

2005-01-01

The Active Aeroelastic Wing research program was a joint program between the U.S. Air Force Research Laboratory and NASA established to investigate the characteristics of an aeroelastic wing and the technique of using wing twist for roll control. The flight test program employed the use of an F/A-18 aircraft modified by reducing the wing torsional stiffness and adding a custom research flight control system. The research flight control system was optimized to maximize roll rate using only wing surfaces to twist the wing while simultaneously maintaining design load limits, stability margins, and handling qualities. NASA Dryden Flight Research Center developed control laws using the software design tool called CONDUIT, which employs a multi-objective function optimization to tune selected control system design parameters. Modifications were made to the Active Aeroelastic Wing implementation in this new software design tool to incorporate the NASA Dryden Flight Research Center nonlinear F/A-18 simulation for time history analysis. This paper describes the design process, including how the control law requirements were incorporated into constraints for the optimization of this specific software design tool. Predicted performance is also compared to results from flight.

Effects of Virtual Reality on the Cognitive Memory and Handgun Accuracy Development of Law Enforcement Neophytes

ERIC Educational Resources Information Center

Wright, Richard A.

2013-01-01

The purpose of this research was to investigate the effects of virtual reality training on the development of cognitive memory and handgun accuracy by law enforcement neophytes. One hundred and six academy students from 6 different academy classes were divided into two groups, experimental and control. The experimental group was exposed to virtual…

Review on the Implementation of the Islamic Republic of Iran about Tobacco Control, Based on MPOWER, in the Framework Convention on Tobacco Control by the World Health Organization.

PubMed

Alimohammadi, Mahmood; Jafari-Mansoorian, Hossein; Hashemi, Seyed Yaser; Momenabadi, Victoria; Ghasemi, Seyed Mehdi; Karimyan, Kamaladdin

2017-07-01

Smoking is the largest preventable cause of death in the world, killing nearly 6 million people annually. This article is an investigation of measures implemented laws in the Iran to study the proposed strategy of control and reduce tobacco use based on the monitor, protect, offer, warn, enforce and raise (MPOWER) policy. All laws approved by the Parliament along with the instructions on tobacco control prepared by the Ministry of Health and Medical Education, Ministry of Industry, Mine and Trade were collected and studied. Moreover, practical steps of Ministry of Health and other organizations were examined in this regard. Iranian Parliament after the adoption of the Framework Convention on Tobacco Control (FCTC) acts to create a comprehensive and systematic program for tobacco control legislation as a first step towards comprehensive national tobacco control and combat. In this law and its implementing guidelines and based on the strategy of MPOWER, specific implement is done to monitor tobacco use and prevention policies, protect people from tobacco smoke, offer help to quit tobacco use, warn about the dangers of tobacco, enforce bans on tobacco advertising, promotion and sponsorship and raise taxes on tobacco. However, the full objectives of the legislation have not achieved yet. According to Iran's membership in the FCTC and executive producer of tobacco control laws and regulations, necessary infrastructure is ready for a serious fight with tobacco use. In Iran, in comparison with developed countries, there is a huge gap between ratified laws and performing of laws.

Robust Gain-Scheduled Fault Tolerant Control for a Transport Aircraft

NASA Technical Reports Server (NTRS)

Shin, Jong-Yeob; Gregory, Irene

2007-01-01

This paper presents an application of robust gain-scheduled control concepts using a linear parameter-varying (LPV) control synthesis method to design fault tolerant controllers for a civil transport aircraft. To apply the robust LPV control synthesis method, the nonlinear dynamics must be represented by an LPV model, which is developed using the function substitution method over the entire flight envelope. The developed LPV model associated with the aerodynamic coefficient uncertainties represents nonlinear dynamics including those outside the equilibrium manifold. Passive and active fault tolerant controllers (FTC) are designed for the longitudinal dynamics of the Boeing 747-100/200 aircraft in the presence of elevator failure. Both FTC laws are evaluated in the full nonlinear aircraft simulation in the presence of the elevator fault and the results are compared to show pros and cons of each control law.

Active stability augmentation of large space structures: A stochastic control problem

NASA Technical Reports Server (NTRS)

Balakrishnan, A. V.

1987-01-01

A problem in SCOLE is that of slewing an offset antenna on a long flexible beam-like truss attached to the space shuttle, with rather stringent pointing accuracy requirements. The relevant methodology aspects in robust feedback-control design for stability augmentation of the beam using on-board sensors is examined. It is framed as a stochastic control problem, boundary control of a distributed parameter system described by partial differential equations. While the framework is mathematical, the emphasis is still on an engineering solution. An abstract mathematical formulation is developed as a nonlinear wave equation in a Hilbert space. That the system is controllable is shown and a feedback control law that is robust in the sense that it does not require quantitative knowledge of system parameters is developed. The stochastic control problem that arises in instrumenting this law using appropriate sensors is treated. Using an engineering first approximation which is valid for small damping, formulas for optimal choice of the control gain are developed.

Feedback linearizing control of a MIMO power system

NASA Astrophysics Data System (ADS)

Ilyes, Laszlo

Prior research has demonstrated that either the mechanical or electrical subsystem of a synchronous electric generator may be controlled using single-input single-output (SISO) nonlinear feedback linearization. This research suggests a new approach which applies nonlinear feedback linearization to a multi-input multi-output (MIMO) model of the synchronous electric generator connected to an infinite bus load model. In this way, the electrical and mechanical subsystems may be linearized and simultaneously decoupled through the introduction of a pair of auxiliary inputs. This allows well known, linear, SISO control methods to be effectively applied to the resulting systems. The derivation of the feedback linearizing control law is presented in detail, including a discussion on the use of symbolic math processing as a development tool. The linearizing and decoupling properties of the control law are validated through simulation. And finally, the robustness of the control law is demonstrated.

Design of a terminal pointer hand controller for teleoperator applications

NASA Technical Reports Server (NTRS)

Saenger, E. L.; Woltosz, W. S.

1973-01-01

The design is described of a hand controller intended to achieve the highest possible compatibility with the hand of the human operator in a teleoperator system. Concepts drawings and model development are discussed along with the development of a prototype, and the mathematical control laws.

Distributed control of large space structures

NASA Technical Reports Server (NTRS)

Schaechter, D. B.

1981-01-01

Theoretical developments and the results of laboratory experiments are treated as they apply to active attitude and vibration control, as well as static shape control. Modern control theory was employed throughout as the method for obtaining estimation and control laws.

A Proven Method for Meeting Export Control Objectives in Postal and Shipping Sectors

DTIC Science & Technology

2015-02-01

months, the USPIS team developed and implemented an export screening standard operating procedure, implemented new and updated processes and systems ...support and protect the U.S. Postal Service and its employees, infrastructure, and customers; enforce the laws that defend the nation’s mail system ...the incidence of mail shipments violating export control laws, regulations, and standards . • Evaluate current processes and systems and identify

Some optimal considerations in attitude control systems. [evaluation of value of relative weighting between time and fuel for relay control law

NASA Technical Reports Server (NTRS)

Boland, J. S., III

1973-01-01

The conventional six-engine reaction control jet relay attitude control law with deadband is shown to be a good linear approximation to a weighted time-fuel optimal control law. Techniques for evaluating the value of the relative weighting between time and fuel for a particular relay control law is studied along with techniques to interrelate other parameters for the two control laws. Vehicle attitude control laws employing control moment gyros are then investigated. Steering laws obtained from the expression for the reaction torque of the gyro configuration are compared to a total optimal attitude control law that is derived from optimal linear regulator theory. This total optimal attitude control law has computational disadvantages in the solving of the matrix Riccati equation. Several computational algorithms for solving the matrix Riccati equation are investigated with respect to accuracy, computational storage requirements, and computational speed.

Who controls the uses of organs after death? Law in the books, law in practice and the view of the people.

PubMed

Naffine, Ngaire; Richards, Bernadette; de Lacey, Sheryl; Braunack-Mayer, Annette; Rogers, Wendy

2012-12-01

The conventional wisdom is that we are free to dispose of our organs at death and that they will be employed according to our wishes. However, this reflects neither the formal law nor medical practice. This article explores the theory underlying the principle of self-determination after death. It presents an overview of Australian law and the way that the law is interpreted in clinical practice. It then presents the results of a community survey on organ disposition, and identifies a gap between community expectations and the current operation of Australian law. It concludes with some specific recommendations for development of the law to align it more closely with contemporary community views.

Space-based Doppler lidar sampling strategies: Algorithm development and simulated observation experiments

NASA Technical Reports Server (NTRS)

Emmitt, G. D.; Wood, S. A.; Morris, M.

1990-01-01

Lidar Atmospheric Wind Sounder (LAWS) Simulation Models (LSM) were developed to evaluate the potential impact of global wind observations on the basic understanding of the Earth's atmosphere and on the predictive skills of current forecast models (GCM and regional scale). Fully integrated top to bottom LAWS Simulation Models for global and regional scale simulations were developed. The algorithm development incorporated the effects of aerosols, water vapor, clouds, terrain, and atmospheric turbulence into the models. Other additions include a new satellite orbiter, signal processor, line of sight uncertainty model, new Multi-Paired Algorithm and wind error analysis code. An atmospheric wind field library containing control fields, meteorological fields, phenomena fields, and new European Center for Medium Range Weather Forecasting (ECMWF) data was also added. The LSM was used to address some key LAWS issues and trades such as accuracy and interpretation of LAWS information, data density, signal strength, cloud obscuration, and temporal data resolution.

Scoring the Strengths and Weaknesses of Underage Drinking Laws in the United States

PubMed Central

Fell, James C.; Thomas, Sue; Scherer, Michael; Fisher, Deborah A.; Romano, Eduardo

2015-01-01

Several studies have examined the impact of a number of minimum legal drinking age 21 (MLDA-21) laws on underage alcohol consumption and alcohol-related crashes in the United States. These studies have contributed to our understanding of how alcohol control laws affect drinking and driving among those who are under age 21. However, much of the extant literature examining underage drinking laws use a “Law/No law” coding which may obscure the variability inherent in each law. Previous literature has demonstrated that inclusion of law strengths may affect outcomes and overall data fit when compared to “Law/No law” coding. In an effort to assess the relative strength of states’ underage drinking legislation, a coding system was developed in 2006 and applied to 16 MLDA-21 laws. The current article updates the previous endeavor and outlines a detailed strength coding mechanism for the current 20 MLDA-21 laws. PMID:26097775

Mothers-in-law and daughters-in-law: Intergenerational relations within the Chinese family in Taiwan.

PubMed

Gallin, R S

1986-03-01

This paper examines the relations of mothers-in-law and daughters-in-law in a Taiwanese village that has changed over the past 25 years from an economic system based primarily on agriculture to one founded predominantly on off-farm employment. Using ethnographic data, it explores Amoss and Harrell's (1980: 5) proposition that the position of old people is a function of a 'cost/contribution balance' compounded by resources controlled. It concludes that economic development shifts power between women in different generations.

Review on the Implementation of the Islamic Republic of Iran about Tobacco Control, Based on MPOWER, in the Framework Convention on Tobacco Control by the World Health Organization

PubMed Central

Alimohammadi, Mahmood; Jafari-Mansoorian, Hossein; Hashemi, Seyed Yaser; Momenabadi, Victoria; Ghasemi, Seyed Mehdi; Karimyan, Kamaladdin

2017-01-01

Background Smoking is the largest preventable cause of death in the world, killing nearly 6 million people annually. This article is an investigation of measures implemented laws in the Iran to study the proposed strategy of control and reduce tobacco use based on the monitor, protect, offer, warn, enforce and raise (MPOWER) policy. Methods All laws approved by the Parliament along with the instructions on tobacco control prepared by the Ministry of Health and Medical Education, Ministry of Industry, Mine and Trade were collected and studied. Moreover, practical steps of Ministry of Health and other organizations were examined in this regard. Findings Iranian Parliament after the adoption of the Framework Convention on Tobacco Control (FCTC) acts to create a comprehensive and systematic program for tobacco control legislation as a first step towards comprehensive national tobacco control and combat. In this law and its implementing guidelines and based on the strategy of MPOWER, specific implement is done to monitor tobacco use and prevention policies, protect people from tobacco smoke, offer help to quit tobacco use, warn about the dangers of tobacco, enforce bans on tobacco advertising, promotion and sponsorship and raise taxes on tobacco. However, the full objectives of the legislation have not achieved yet. Conclusion According to Iran’s membership in the FCTC and executive producer of tobacco control laws and regulations, necessary infrastructure is ready for a serious fight with tobacco use. In Iran, in comparison with developed countries, there is a huge gap between ratified laws and performing of laws. PMID:29657699

23 CFR 750.705 - Effective control.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 23 Highways 1 2013-04-01 2013-04-01 false Effective control. 750.705 Section 750.705 Highways... BEAUTIFICATION Outdoor Advertising Control § 750.705 Effective control. In order to provide effective control of... of applicable control requirements will apply; (h) Develop laws, regulations, and procedures to...

23 CFR 750.705 - Effective control.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 23 Highways 1 2011-04-01 2011-04-01 false Effective control. 750.705 Section 750.705 Highways... BEAUTIFICATION Outdoor Advertising Control § 750.705 Effective control. In order to provide effective control of... of applicable control requirements will apply; (h) Develop laws, regulations, and procedures to...

23 CFR 750.705 - Effective control.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 23 Highways 1 2012-04-01 2012-04-01 false Effective control. 750.705 Section 750.705 Highways... BEAUTIFICATION Outdoor Advertising Control § 750.705 Effective control. In order to provide effective control of... of applicable control requirements will apply; (h) Develop laws, regulations, and procedures to...

23 CFR 750.705 - Effective control.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 23 Highways 1 2014-04-01 2014-04-01 false Effective control. 750.705 Section 750.705 Highways... BEAUTIFICATION Outdoor Advertising Control § 750.705 Effective control. In order to provide effective control of... of applicable control requirements will apply; (h) Develop laws, regulations, and procedures to...

23 CFR 750.705 - Effective control.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 23 Highways 1 2010-04-01 2010-04-01 false Effective control. 750.705 Section 750.705 Highways... BEAUTIFICATION Outdoor Advertising Control § 750.705 Effective control. In order to provide effective control of... of applicable control requirements will apply; (h) Develop laws, regulations, and procedures to...

Modeling and controlling a robotic convoy using guidance laws strategies.

PubMed

Belkhouche, Fethi; Belkhouche, Boumediene

2005-08-01

This paper deals with the problem of modeling and controlling a robotic convoy. Guidance laws techniques are used to provide a mathematical formulation of the problem. The guidance laws used for this purpose are the velocity pursuit, the deviated pursuit, and the proportional navigation. The velocity pursuit equations model the robot's path under various sensors based control laws. A systematic study of the tracking problem based on this technique is undertaken. These guidance laws are applied to derive decentralized control laws for the angular and linear velocities. For the angular velocity, the control law is directly derived from the guidance laws after considering the relative kinematics equations between successive robots. The second control law maintains the distance between successive robots constant by controlling the linear velocity. This control law is derived by considering the kinematics equations between successive robots under the considered guidance law. Properties of the method are discussed and proven. Simulation results confirm the validity of our approach, as well as the validity of the properties of the method. Index Terms-Guidance laws, relative kinematics equations, robotic convoy, tracking.

Active control of flexible structures using a fuzzy logic algorithm

NASA Astrophysics Data System (ADS)

Cohen, Kelly; Weller, Tanchum; Ben-Asher, Joseph Z.

2002-08-01

This study deals with the development and application of an active control law for the vibration suppression of beam-like flexible structures experiencing transient disturbances. Collocated pairs of sensors/actuators provide active control of the structure. A design methodology for the closed-loop control algorithm based on fuzzy logic is proposed. First, the behavior of the open-loop system is observed. Then, the number and locations of collocated actuator/sensor pairs are selected. The proposed control law, which is based on the principles of passivity, commands the actuator to emulate the behavior of a dynamic vibration absorber. The absorber is tuned to a targeted frequency, whereas the damping coefficient of the dashpot is varied in a closed loop using a fuzzy logic based algorithm. This approach not only ensures inherent stability associated with passive absorbers, but also circumvents the phenomenon of modal spillover. The developed controller is applied to the AFWAL/FIB 10 bar truss. Simulated results using MATLAB© show that the closed-loop system exhibits fairly quick settling times and desirable performance, as well as robustness characteristics. To demonstrate the robustness of the control system to changes in the temporal dynamics of the flexible structure, the transient response to a considerably perturbed plant is simulated. The modal frequencies of the 10 bar truss were raised as well as lowered substantially, thereby significantly perturbing the natural frequencies of vibration. For these cases, too, the developed control law provides adequate settling times and rates of vibrational energy dissipation.

Integrated structure/control law design by multilevel optimization

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.; Schmidt, David K.

1989-01-01

A new approach to integrated structure/control law design based on multilevel optimization is presented. This new approach is applicable to aircraft and spacecraft and allows for the independent design of the structure and control law. Integration of the designs is achieved through use of an upper level coordination problem formulation within the multilevel optimization framework. The method requires the use of structure and control law design sensitivity information. A general multilevel structure/control law design problem formulation is given, and the use of Linear Quadratic Gaussian (LQG) control law design and design sensitivity methods within the formulation is illustrated. Results of three simple integrated structure/control law design examples are presented. These results show the capability of structure and control law design tradeoffs to improve controlled system performance within the multilevel approach.

Digital-flutter-suppression-system investigations for the active flexible wing wind-tunnel model

NASA Technical Reports Server (NTRS)

Perry, Boyd, III; Mukhopadhyay, Vivek; Hoadley, Sherwood Tiffany; Cole, Stanley R.; Buttrill, Carey S.

1990-01-01

Active flutter suppression control laws were designed, implemented, and tested on an aeroelastically-scaled wind-tunnel model in the NASA Langley Transonic Dynamics Tunnel. One of the control laws was successful in stabilizing the model while the dynamic pressure was increased to 24 percent greater than the measured open-loop flutter boundary. Other accomplishments included the design, implementation, and successful operation of a one-of-a-kind digital controller, the design and use of two simulation methods to support the project, and the development and successful use of a methodology for online controller performance evaluation.

Digital-flutter-suppression-system investigations for the active flexible wing wind-tunnel model

NASA Technical Reports Server (NTRS)

Perry, Boyd, III; Mukhopadhyay, Vivek; Hoadley, Sherwood T.; Cole, Stanley R.; Buttrill, Carey S.; Houck, Jacob A.

1990-01-01

Active flutter suppression control laws were designed, implemented, and tested on an aeroelastically-scaled wind tunnel model in the NASA Langley Transonic Dynamics Tunnel. One of the control laws was successful in stabilizing the model while the dynamic pressure was increased to 24 percent greater than the measured open-loop flutter boundary. Other accomplishments included the design, implementation, and successful operation of a one-of-a-kind digital controller, the design and use of two simulation methods to support the project, and the development and successful use of a methodology for on-line controller performance evaluation.

A high-fidelity airbus benchmark for system fault detection and isolation and flight control law clearance

NASA Astrophysics Data System (ADS)

Goupil, Ph.; Puyou, G.

2013-12-01

This paper presents a high-fidelity generic twin engine civil aircraft model developed by Airbus for advanced flight control system research. The main features of this benchmark are described to make the reader aware of the model complexity and representativeness. It is a complete representation including the nonlinear rigid-body aircraft model with a full set of control surfaces, actuator models, sensor models, flight control laws (FCL), and pilot inputs. Two applications of this benchmark in the framework of European projects are presented: FCL clearance using optimization and advanced fault detection and diagnosis (FDD).

Should Cops Be Spies? Evaluating the Collection and Sharing of National Security Intelligence by State, Local and Tribal Law Enforcement

DTIC Science & Technology

2013-03-01

international organized crime , illegal immigration, financial institution fraud and money laundering. Policymakers increasingly view domestic law...approach to crime control, focusing upon the identification, analysis and management of persisting and developing problems or risks (de Lint, 2006

Human trafficking law and social structures.

PubMed

Wooditch, Alese

2012-08-01

Human trafficking has only recently emerged at the forefront of policy reform, even in developed nations. Yet, heightened awareness of the issue has not translated into effective policy as the majority of nations have ineffective antitrafficking practices; many countries have failed to criminalize human trafficking, whereas others do not actively enforce statutes in place. By applying Black's theory of law, this study offers a preliminary understanding into the variation of global prosecutorial efforts in human trafficking and adequacy of antitrafficking law. To isolate this relationship, the effects of trafficking markets are controlled. As with prior research, the study finds limited support for the theory. The article concludes with a discussion on the implications of the quantity of antitrafficking law and morphology association for policy development.

Flight Control Development for the ARH-70 Armed Reconnaissance Helicopter Program

NASA Technical Reports Server (NTRS)

Christensen, Kevin T.; Campbell, Kip G.; Griffith, Carl D.; Ivler, Christina M.; Tischler, Mark B.; Harding, Jeffrey W.

2008-01-01

In July 2005, Bell Helicopter won the U.S. Army's Armed Reconnaissance Helicopter competition to produce a replacement for the OH-58 Kiowa Warrior capable of performing the armed reconnaissance mission. To meet the U.S. Army requirement that the ARH-70A have Level 1 handling qualities for the scout rotorcraft mission task elements defined by ADS-33E-PRF, Bell equipped the aircraft with their generic automatic flight control system (AFCS). Under the constraints of the tight ARH-70A schedule, the development team used modem parameter identification and control law optimization techniques to optimize the AFCS gains to simultaneously meet multiple handling qualities design criteria. This paper will show how linear modeling, control law optimization, and simulation have been used to produce a Level 1 scout rotorcraft for the U.S. Army, while minimizing the amount of flight testing required for AFCS development and handling qualities evaluation of the ARH-70A.

Discrete-time entropy formulation of optimal and adaptive control problems

NASA Technical Reports Server (NTRS)

Tsai, Yweting A.; Casiello, Francisco A.; Loparo, Kenneth A.

1992-01-01

The discrete-time version of the entropy formulation of optimal control of problems developed by G. N. Saridis (1988) is discussed. Given a dynamical system, the uncertainty in the selection of the control is characterized by the probability distribution (density) function which maximizes the total entropy. The equivalence between the optimal control problem and the optimal entropy problem is established, and the total entropy is decomposed into a term associated with the certainty equivalent control law, the entropy of estimation, and the so-called equivocation of the active transmission of information from the controller to the estimator. This provides a useful framework for studying the certainty equivalent and adaptive control laws.

Neuromorphic learning of continuous-valued mappings from noise-corrupted data. Application to real-time adaptive control

NASA Technical Reports Server (NTRS)

Troudet, Terry; Merrill, Walter C.

1990-01-01

The ability of feed-forward neural network architectures to learn continuous valued mappings in the presence of noise was demonstrated in relation to parameter identification and real-time adaptive control applications. An error function was introduced to help optimize parameter values such as number of training iterations, observation time, sampling rate, and scaling of the control signal. The learning performance depended essentially on the degree of embodiment of the control law in the training data set and on the degree of uniformity of the probability distribution function of the data that are presented to the net during sequence. When a control law was corrupted by noise, the fluctuations of the training data biased the probability distribution function of the training data sequence. Only if the noise contamination is minimized and the degree of embodiment of the control law is maximized, can a neural net develop a good representation of the mapping and be used as a neurocontroller. A multilayer net was trained with back-error-propagation to control a cart-pole system for linear and nonlinear control laws in the presence of data processing noise and measurement noise. The neurocontroller exhibited noise-filtering properties and was found to operate more smoothly than the teacher in the presence of measurement noise.

Alternatives for jet engine control

NASA Technical Reports Server (NTRS)

Sain, M. K.

1983-01-01

Tensor model order reduction, recursive tensor model identification, input design for tensor model identification, software development for nonlinear feedback control laws based upon tensors, and development of the CATNAP software package for tensor modeling, identification and simulation were studied. The last of these are discussed.

Evaluation of control laws and actuator locations for control systems applicable to deformable astronomical telescope mirrors

NASA Technical Reports Server (NTRS)

Ostroff, A. J.

1973-01-01

Some of the major difficulties associated with large orbiting astronomical telescopes are the cost of manufacturing the primary mirror to precise tolerances and the maintaining of diffraction-limited tolerances while in orbit. One successfully demonstrated approach for minimizing these problem areas is the technique of actively deforming the primary mirror by applying discrete forces to the rear of the mirror. A modal control technique, as applied to active optics, has previously been developed and analyzed. The modal control technique represents the plant to be controlled in terms of its eigenvalues and eigenfunctions which are estimated via numerical approximation techniques. The report includes an extension of previous work using the modal control technique and also describes an optimal feedback controller. The equations for both control laws are developed in state-space differential form and include such considerations as stability, controllability, and observability. These equations are general and allow the incorporation of various mode-analyzer designs; two design approaches are presented. The report also includes a technique for placing actuator and sensor locations at points on the mirror based upon the flexibility matrix of the uncontrolled or unobserved modes of the structure. The locations selected by this technique are used in the computer runs which are described. The results are based upon three different initial error distributions, two mode-analyzer designs, and both the modal and optimal control laws.

A reactive torque control law for gyroscopically controlled space vehicles

NASA Technical Reports Server (NTRS)

Farmer, J. E.

1973-01-01

A method of control is developed based on the reactive torques as seen by the individual CMG gimbals. The application of a torque to the gimbal of a CMG rotates the momentum vector and applies a torque to the spacecraft according to well-known laws. The response (rotation) of the vehicle produces a reverse or reaction torque opposing the torque producing the gimbal movement. The reactive torque and the pseudoinverse control schemes are contrasted in order to point out the simplicity of the first method. Simulation was performed only to the extent necessary to prove that reactive torque stabilization and control is feasible.

Nutation control during precession of a spin-stabilized spacecraft

NASA Technical Reports Server (NTRS)

1974-01-01

Precession maneuver control laws for single-spin spacecraft are investigated so that nutation is concurrently controlled. Analysis has led to the development of two types of control laws employing precession modulation for concurrent nutation control. Results were verified through digital simulation of a Synchronous Meteorological Satellite (SMS) configuration. An addition research effort was undertaken to investigate the cause and elimination of nutation anomalies in dual-spin spacecraft. A literature search was conducted and a dual-spin configuration was simulated to verify that nutational anomalies are not predicted by the existing nonlinear model. No conclusions were drawn as to the cause of the observed nutational anomalies in dual-spin spacecraft.

A slewing control experiment for flexible structures

NASA Technical Reports Server (NTRS)

Juang, J.-N.; Horta, L. G.; Robertshaw, H. H.

1985-01-01

A hardware set-up has been developed to study slewing control for flexible structures including a steel beam and a solar panel. The linear optimal terminal control law is used to design active controllers which are implemented in an analog computer. The objective of this experiment is to demonstrate and verify the dynamics and optimal terminal control laws as applied to flexible structures for large angle maneuver. Actuation is provided by an electric motor while sensing is given by strain gages and angle potentiometer. Experimental measurements are compared with analytical predictions in terms of modal parameters of the system stability matrix and sufficient agreement is achieved to validate the theory.

Active control of aerothermoelastic effects for a conceptual hypersonic aircraft

NASA Technical Reports Server (NTRS)

Heeg, Jennifer; Gilbert, Michael G.; Pototzky, Anthony S.

1990-01-01

This paper describes the procedures for an results of aeroservothermoelastic studies. The objectives of these studies were to develop the necessary procedures for performing an aeroelastic analysis of an aerodynamically heated vehicle and to analyze a configuration in the classical 'cold' state and in a 'hot' state. Major tasks include the development of the structural and aerodynamic models, open loop analyses, design of active control laws for improving dynamic responses and analyses of the closed loop vehicles. The analyses performed focused on flutter speed calculations, short period eigenvalue trends and statistical analyses of the vehicle response to controls and turbulence. Improving the ride quality of the vehicle and raising the flutter boundary of the aerodynamically-heated vehicle up to that of the cold vehicle were the objectives of the control law design investigations.

New techniques for test development for tactical auto-pilots using microprocessors

NASA Astrophysics Data System (ADS)

Shemeta, E. H.

1980-07-01

This paper reports on a demonstration of the application of the method to generate system level tests for a typical tactical missile autopilot. The test algorithms are based on the autopilot control law. When loaded on the tester with appropriate control information, the complete autopilot is tested to establish if the specified control law requirements are met. Thus, the test procedure not only checks to see if the hardware is functional, but also checks the operational software. The technique also uses a 'learning' mode to allow minor timing or functional deviations from the expected responses to be incorporated in the test procedures. A potential application of this test development technique is the extraction of production test data for the various subassemblies. The technique will 'learn' the input-output patterns forming the basis for developement and production tests. If successful, these new techniques should allow the test development process to keep pace with semiconductor progress.

An integrated approach to evaluate policies for controlling traffic law violations.

PubMed

Mehmood, Arif

2010-03-01

Modeling dynamics of the driver behavior is a complex problem. In this paper a system approach is introduced to model and to analyze the driver behavior related to traffic law violations in the Emirate of Abu Dhabi. This paper demonstrates how the theoretical relationships between different factors can be expressed formally, and how the resulting model can assist in evaluating potential benefits of various policies to control the traffic law violations Using system approach, an integrated dynamic simulation model is developed, and model is tested to simulate the driver behavior for violating traffic laws during 2002-2007 in the Emirate of Abu Dhabi. The dynamic simulation model attempts to address the questions: (1) "what" interventions should be implemented to reduce and eventually control traffic violations which will lead to improving road safety and (2) "how" to justify those interventions will be effective or ineffective to control the violations in different transportation conditions. The simulation results reveal promising capability of applying system approach in the policy evaluation studies. Copyright 2009 Elsevier Ltd. All rights reserved.

The politics of space - Who owns what? Earth law for space

NASA Technical Reports Server (NTRS)

Hosenball, S. N.

1983-01-01

Topics of concern in developing space law, i.e., international disagreements, the present status of space law, and requirements for future space activities, are discussed. Factors inhibiting agreements include governments that wish to control specific regions of GEO, the refusal of several countries to permit international DBS television broadcasts over their boundaries, the possibility that weapons may be placed in space, and the lack of international laws governing humans and industries in space. It is noted that any state entering an international agreement has relinquished some of its sovereignty. The Outer Space Treaty has removed celestial bodies from claims of national appropriation. States retain sovereignty over their citizens who travel in space, a problematical concept once internationally-manned settlements in space or on the moon are established. It is recommended that space law develop mainly in reaction to the implementation of new space capabilities in order to avoid hindering space activities.

Implementation of Nonlinear Control Laws for an Optical Delay Line

NASA Technical Reports Server (NTRS)

Hench, John J.; Lurie, Boris; Grogan, Robert; Johnson, Richard

2000-01-01

This paper discusses the implementation of a globally stable nonlinear controller algorithm for the Real-Time Interferometer Control System Testbed (RICST) brassboard optical delay line (ODL) developed for the Interferometry Technology Program at the Jet Propulsion Laboratory. The control methodology essentially employs loop shaping to implement linear control laws. while utilizing nonlinear elements as means of ameliorating the effects of actuator saturation in its coarse, main, and vernier stages. The linear controllers were implemented as high-order digital filters and were designed using Bode integral techniques to determine the loop shape. The nonlinear techniques encompass the areas of exact linearization, anti-windup control, nonlinear rate limiting and modal control. Details of the design procedure are given as well as data from the actual mechanism.

Automatic control of a liquid nitrogen cooled, closed-circuit, cryogenic pressure tunnel

NASA Technical Reports Server (NTRS)

Balakrishna, S.; Goglia, G. L.

1980-01-01

The control system design, performance analysis, microprocesser based controller software development, and specifications for the Transonic Cryogenic Tunnel (TCT) are discussed. The control laws for the single-input single-output controllers were tested on the TCT simulator, and successfully demonstrated on the TCT.

Individual Autonomy, Law, and Technology: Should Soft Determinism Guide Legal Analysis?

ERIC Educational Resources Information Center

Cockfield, Arthur J.

2010-01-01

How one thinks about the relationship between individual autonomy (sometimes referred to as individual willpower or human agency) and technology can influence the way legal thinkers develop policy at the intersection of law and technology. Perspectives that fall toward the "machines control us" end of the spectrum may support more interventionist…

A Real-Time Method for Estimating Viscous Forebody Drag Coefficients

NASA Technical Reports Server (NTRS)

Whitmore, Stephen A.; Hurtado, Marco; Rivera, Jose; Naughton, Jonathan W.

2000-01-01

This paper develops a real-time method based on the law of the wake for estimating forebody skin-friction coefficients. The incompressible law-of-the-wake equations are numerically integrated across the boundary layer depth to develop an engineering model that relates longitudinally averaged skin-friction coefficients to local boundary layer thickness. Solutions applicable to smooth surfaces with pressure gradients and rough surfaces with negligible pressure gradients are presented. Model accuracy is evaluated by comparing model predictions with previously measured flight data. This integral law procedure is beneficial in that skin-friction coefficients can be indirectly evaluated in real-time using a single boundary layer height measurement. In this concept a reference pitot probe is inserted into the flow, well above the anticipated maximum thickness of the local boundary layer. Another probe is servomechanism-driven and floats within the boundary layer. A controller regulates the position of the floating probe. The measured servomechanism position of this second probe provides an indirect measurement of both local and longitudinally averaged skin friction. Simulation results showing the performance of the control law for a noisy boundary layer are then presented.

76 FR 4366 - Iipay Nation of Santa Ysabel Liquor Control Law

Federal Register 2010, 2011, 2012, 2013, 2014

2011-01-25

... Law AGENCY: Bureau of Indian Affairs, Interior. ACTION: Notice. SUMMARY: This notice publishes Liquor Control Law No. LB-06-08 of the Iipay Nation of Santa Ysabel (Nation). The Liquor Control Law regulates... are located in Indian country and this Liquor Control Law allows for possession and sale of alcoholic...

Robust Operation of Tendon-Driven Robot Fingers Using Force and Position-Based Control Laws

NASA Technical Reports Server (NTRS)

Hargrave, Brian (Inventor); Abdallah, Muhammad E (Inventor); Reiland, Matthew J (Inventor); Diftler, Myron A (Inventor); Strawser, Philip A (Inventor); Platt, Jr., Robert J. (Inventor); Ihrke, Chris A. (Inventor)

2013-01-01

A robotic system includes a tendon-driven finger and a control system. The system controls the finger via a force-based control law when a tension sensor is available, and via a position-based control law when a sensor is not available. Multiple tendons may each have a corresponding sensor. The system selectively injects a compliance value into the position-based control law when only some sensors are available. A control system includes a host machine and a non-transitory computer-readable medium having a control process, which is executed by the host machine to control the finger via the force- or position-based control law. A method for controlling the finger includes determining the availability of a tension sensor(s), and selectively controlling the finger, using the control system, via the force or position-based control law. The position control law allows the control system to resist disturbances while nominally maintaining the initial state of internal tendon tensions.

Proximity Operations for Space Situational Awareness Spacecraft Rendezvous and Maneuvering using Numerical Simulations and Fuzzy Logic

NASA Astrophysics Data System (ADS)

Carrico, T.; Langster, T.; Carrico, J.; Alfano, S.; Loucks, M.; Vallado, D.

The authors present several spacecraft rendezvous and close proximity maneuvering techniques modeled with a high-precision numerical integrator using full force models and closed loop control with a Fuzzy Logic intelligent controller to command the engines. The authors document and compare the maneuvers, fuel use, and other parameters. This paper presents an innovative application of an existing capability to design, simulate and analyze proximity maneuvers; already in use for operational satellites performing other maneuvers. The system has been extended to demonstrate the capability to develop closed loop control laws to maneuver spacecraft in close proximity to another, including stand-off, docking, lunar landing and other operations applicable to space situational awareness, space based surveillance, and operational satellite modeling. The fully integrated end-to-end trajectory ephemerides are available from the authors in electronic ASCII text by request. The benefits of this system include: A realistic physics-based simulation for the development and validation of control laws A collaborative engineering environment for the design, development and tuning of spacecraft law parameters, sizing actuators (i.e., rocket engines), and sensor suite selection. An accurate simulation and visualization to communicate the complexity, criticality, and risk of spacecraft operations. A precise mathematical environment for research and development of future spacecraft maneuvering engineering tasks, operational planning and forensic analysis. A closed loop, knowledge-based control example for proximity operations. This proximity operations modeling and simulation environment will provide a valuable adjunct to programs in military space control, space situational awareness and civil space exploration engineering and decision making processes.

A Control Model: Interpretation of Fitts' Law

NASA Technical Reports Server (NTRS)

Connelly, E. M.

1984-01-01

The analytical results for several models are given: a first order model where it is assumed that the hand velocity can be directly controlled, and a second order model where it is assumed that the hand acceleration can be directly controlled. Two different types of control-laws are investigated. One is linear function of the hand error and error rate; the other is the time-optimal control law. Results show that the first and second order models with the linear control-law produce a movement time (MT) function with the exact form of the Fitts' Law. The control-law interpretation implies that the effect of target width on MT must be a result of the vertical motion which elevates the hand from the starting point and drops it on the target at the target edge. The time optimal control law did not produce a movement-time formula simular to Fitt's Law.

Finite-time containment control of perturbed multi-agent systems based on sliding-mode control

NASA Astrophysics Data System (ADS)

Yu, Di; Ji, Xiang Yang

2018-01-01

Aimed at faster convergence rate, this paper investigates finite-time containment control problem for second-order multi-agent systems with norm-bounded non-linear perturbation. When topology between the followers are strongly connected, the nonsingular fast terminal sliding-mode error is defined, corresponding discontinuous control protocol is designed and the appropriate value range of control parameter is obtained by applying finite-time stability analysis, so that the followers converge to and move along the desired trajectories within the convex hull formed by the leaders in finite time. Furthermore, on the basis of the sliding-mode error defined, the corresponding distributed continuous control protocols are investigated with fast exponential reaching law and double exponential reaching law, so as to make the followers move to the small neighbourhoods of their desired locations and keep within the dynamic convex hull formed by the leaders in finite time to achieve practical finite-time containment control. Meanwhile, we develop the faster control scheme according to comparison of the convergence rate of these two different reaching laws. Simulation examples are given to verify the correctness of theoretical results.

Tribal organizations and energy development: Recognized sovereignty, regulations, and planning

NASA Astrophysics Data System (ADS)

Wilson, Amy James

Tribal governments' capacity to implement land use controls within their Nations is limited by the United States Constitution and federal law; however, tribal governments have inherent sovereignty to protect, guide, and govern the lands under their jurisdiction to protect and enhance the safety, health, and welfare of their members. The aim of this thesis was to investigate and identify (1) the extent to which tribal Nations have sovereignty over their lands and authority to regulate land use within their jurisdiction and (2) the present status and extent to which Native American tribal governments use their sovereignty over land use development concerning oil and natural gas development within their jurisdiction. The study was qualitative in nature and focused on a comprehensive archival review and a one-case case study. Constitutional law, federal Indian law, environmental law, and tribal law were considered. The thesis first examines the results of the archival review, which demonstrates that tribes, while limited by federal law, have sovereignty and authority to control land use within their territories. The Three Affiliated Tribes of the Fort Berthold Reservation were also examined. The Tribes were chosen based on location, level of oil and natural gas production, and accessibility of information. The most current information available was used for the study. The data for the study was obtained from the Internet. The research suggests that tribes are implementing land use controls and participating in land use and comprehensive planning; however, they are not doing so to the extent of their sovereignty. This study demonstrates that tribal governments do indeed have authority over their lands and resources and cannot fully take advantage of their sovereignty without practicing self-governance over their natural, built, and human environments. Questions remain regarding the reasons that tribal governments are not implementing land use controls and engaging in land use planning to the extent of their sovereignty. Further research is needed to understand the reasons that tribal organizations are not taking full advantage of the existing sovereignty of their lands and resources.

Dual-quaternion based fault-tolerant control for spacecraft formation flying with finite-time convergence.

PubMed

Dong, Hongyang; Hu, Qinglei; Ma, Guangfu

2016-03-01

Study results of developing control system for spacecraft formation proximity operations between a target and a chaser are presented. In particular, a coupled model using dual quaternion is employed to describe the proximity problem of spacecraft formation, and a nonlinear adaptive fault-tolerant feedback control law is developed to enable the chaser spacecraft to track the position and attitude of the target even though its actuator occurs fault. Multiple-task capability of the proposed control system is further demonstrated in the presence of disturbances and parametric uncertainties as well. In addition, the practical finite-time stability feature of the closed-loop system is guaranteed theoretically under the designed control law. Numerical simulation of the proposed method is presented to demonstrate the advantages with respect to interference suppression, fast tracking, fault tolerant and practical finite-time stability. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Task oriented nonlinear control laws for telerobotic assembly operations

NASA Technical Reports Server (NTRS)

Walker, R. A.; Ward, L. S.; Elia, C. F.

1987-01-01

The goal of this research is to achieve very intelligent telerobotic controllers which are capable of receiving high-level commands from the human operator and implementing them in an adaptive manner in the object/task/manipulator workspace. Initiatives by the authors at Integrated Systems, Inc. to identify and develop the key technologies necessary to create such a flexible, highly programmable, telerobotic controller are presented. The focus of the discussion is on the modeling of insertion tasks in three dimensions and nonlinear implicit force feedback control laws which incorporate tool/workspace constraints. Preliminary experiments with dual arm beam assembly in 2-D are presented.

The effects of Poynting-Robertson drag on solar sails

NASA Astrophysics Data System (ADS)

Abd El-Salam, F. A.

2018-06-01

In the present work, the concept of solar sailing and its developing spacecraft are presented. The effects of Poynting-Robertson drag on solar sails are considered. Some analytical control laws with some mentioned input constraints for optimizing solar sails dynamics in heliocentric orbit using Lagrange's planetary equations are obtained. Optimum force vector in a required direction is maximized by deriving optimal sail cone angle. New control laws that maximize thrust to obtain certain required maximization in some particular orbital element are obtained.

Intelligent on-line fault tolerant control for unanticipated catastrophic failures.

PubMed

Yen, Gary G; Ho, Liang-Wei

2004-10-01

As dynamic systems become increasingly complex, experience rapidly changing environments, and encounter a greater variety of unexpected component failures, solving the control problems of such systems is a grand challenge for control engineers. Traditional control design techniques are not adequate to cope with these systems, which may suffer from unanticipated dynamic failures. In this research work, we investigate the on-line fault tolerant control problem and propose an intelligent on-line control strategy to handle the desired trajectories tracking problem for systems suffering from various unanticipated catastrophic faults. Through theoretical analysis, the sufficient condition of system stability has been derived and two different on-line control laws have been developed. The approach of the proposed intelligent control strategy is to continuously monitor the system performance and identify what the system's current state is by using a fault detection method based upon our best knowledge of the nominal system and nominal controller. Once a fault is detected, the proposed intelligent controller will adjust its control signal to compensate for the unknown system failure dynamics by using an artificial neural network as an on-line estimator to approximate the unexpected and unknown failure dynamics. The first control law is derived directly from the Lyapunov stability theory, while the second control law is derived based upon the discrete-time sliding mode control technique. Both control laws have been implemented in a variety of failure scenarios to validate the proposed intelligent control scheme. The simulation results, including a three-tank benchmark problem, comply with theoretical analysis and demonstrate a significant improvement in trajectory following performance based upon the proposed intelligent control strategy.

HORMONAL CONTROL OF OVARIAN FUNCTION FOLLOWING CHLOROTRIAZINE EXPOSURE: EFFECT ON REPRODUCTIVE FUNCTION AND MAMMARY GLAND TUMOR DEVELOPMENT

EPA Science Inventory

Hormonal Control of Ovarian Function Following Chlorotriazine Exposure: Effect on Reproductive Function and Mammary Gland Tumor Development.

Ralph L. Cooper, Susan C. Laws, Michael G. Narotsky, Jerome M. Goldman, and Tammy E. Stoker

Abstract
The studies review...

Delay compensation in integrated communication and control systems. I - Conceptual development and analysis

NASA Technical Reports Server (NTRS)

Luck, Rogelio; Ray, Asok

1990-01-01

A procedure for compensating for the effects of distributed network-induced delays in integrated communication and control systems (ICCS) is proposed. The problem of analyzing systems with time-varying and possibly stochastic delays could be circumvented by use of a deterministic observer which is designed to perform under certain restrictive but realistic assumptions. The proposed delay-compensation algorithm is based on a deterministic state estimator and a linear state-variable-feedback control law. The deterministic observer can be replaced by a stochastic observer without any structural modifications of the delay compensation algorithm. However, if a feedforward-feedback control law is chosen instead of the state-variable feedback control law, the observer must be modified as a conventional nondelayed system would be. Under these circumstances, the delay compensation algorithm would be accordingly changed. The separation principle of the classical Luenberger observer holds true for the proposed delay compensator. The algorithm is suitable for ICCS in advanced aircraft, spacecraft, manufacturing automation, and chemical process applications.

Concerns in Water Supply and Pollution Control: Legal, Social, and Economic.

ERIC Educational Resources Information Center

Burke, D. Barlow, Jr.; And Others

This bulletin contains three articles which focus on ground water's potential as a dependable supply source and some of the problems impeding the development of that potential. The authors' concerns are discussed from the vantage point of their areas of specialization: law, sociology, and economics. The first author states that water law abounds…

Preliminary Assessment of Optimal Longitudinal-Mode Control for Drag Reduction through Distributed Aeroelastic Shaping

NASA Technical Reports Server (NTRS)

Ippolito, Corey; Nguyen, Nhan; Lohn, Jason; Dolan, John

2014-01-01

The emergence of advanced lightweight materials is resulting in a new generation of lighter, flexible, more-efficient airframes that are enabling concepts for active aeroelastic wing-shape control to achieve greater flight efficiency and increased safety margins. These elastically shaped aircraft concepts require non-traditional methods for large-scale multi-objective flight control that simultaneously seek to gain aerodynamic efficiency in terms of drag reduction while performing traditional command-tracking tasks as part of a complete guidance and navigation solution. This paper presents results from a preliminary study of a notional multi-objective control law for an aeroelastic flexible-wing aircraft controlled through distributed continuous leading and trailing edge control surface actuators. This preliminary study develops and analyzes a multi-objective control law derived from optimal linear quadratic methods on a longitudinal vehicle dynamics model with coupled aeroelastic dynamics. The controller tracks commanded attack-angle while minimizing drag and controlling wing twist and bend. This paper presents an overview of the elastic aircraft concept, outlines the coupled vehicle model, presents the preliminary control law formulation and implementation, presents results from simulation, provides analysis, and concludes by identifying possible future areas for research

Analytical investigation of the dynamics of tethered constellations in Earth orbit, phase 2

NASA Astrophysics Data System (ADS)

Lorenzini, E. C.; Arnold, D. A.; Cosmo, M.; Grossi, M. D.

1986-10-01

The following topics related to the dynamics of the 4-mass tethered system are addressed: (1) the development of damping algorithms for damping the out-of-plane libration of the system and the interaction of the out-of-plane control with the other degrees of freedom; and (2) the development of environmental models to be added to the dynamics simulation computer code. The environmental models are specifically a new drag routine based on the Jacchia's 1977 model, a J(2) model and an accurate thermal model of the wire. Regarding topic (1) a survey of various out-of-plane libration control laws was carried out. Consequently a yo-yo control law with amplitude of the tether length variation proportional to the amplitude of the out-of-game libration has been selected. This control law provides good damping when applied to a (theoretical) two-dimensional system. In the actual 3-dimensional 4-mass tethered system, however, energy is transferred to the least damped degrees of freedom (the out-of-plane lateral deflections are still undamped in the present simulations) in such a way as to decrease the effectiveness of the algorithm for out-of-plane libration control. The addition of damping algorithms for the out-of-plane lateral deflections is therefore necessary.

Analytical investigation of the dynamics of tethered constellations in Earth orbit, phase 2

NASA Technical Reports Server (NTRS)

Lorenzini, E. C.; Arnold, D. A.; Cosmo, M.; Grossi, M. D.

1986-01-01

The following topics related to the dynamics of the 4-mass tethered system are addressed: (1) the development of damping algorithms for damping the out-of-plane libration of the system and the interaction of the out-of-plane control with the other degrees of freedom; and (2) the development of environmental models to be added to the dynamics simulation computer code. The environmental models are specifically a new drag routine based on the Jacchia's 1977 model, a J(2) model and an accurate thermal model of the wire. Regarding topic (1) a survey of various out-of-plane libration control laws was carried out. Consequently a yo-yo control law with amplitude of the tether length variation proportional to the amplitude of the out-of-game libration has been selected. This control law provides good damping when applied to a (theoretical) two-dimensional system. In the actual 3-dimensional 4-mass tethered system, however, energy is transferred to the least damped degrees of freedom (the out-of-plane lateral deflections are still undamped in the present simulations) in such a way as to decrease the effectiveness of the algorithm for out-of-plane libration control. The addition of damping algorithms for the out-of-plane lateral deflections is therefore necessary.

Infectious disease-related laws: prevention and control measures.

PubMed

Park, Mijeong

2017-01-01

This study examines recently revised Korean government legislation addressing global infectious disease control for public health emergency situations, with the aim of proposing more rational, effective and realistic interpretations and applications for improvement of law. The Korea reported its first laboratory-confirmed case of Middle East Respiratory Syndrome (MERS) coronavirus on May 20, 2015. Since the first indexed case, Korean public health authorities enforced many public health measures that were not authorized in the law; the scope of the current law was too limited to cover MERS. Korea has three levels of government: the central government, special self-governing provinces, and si/gun/gu. Unfortunately, the Infectious Disease Control and Prevention Act does not designate the specific roles of each level of government, and does not state how these governmental branches should be vertically integrated in a state of emergency. When thinking about these policy questions, we should be especially concerned about introducing a new act that deals with all matters relevant to emerging infectious diseases. The aim would be to develop a structure that specifies the roles of each level of government, and facilitates the close collaboration among them, then enacting this in law for the prevention and response of infectious disease. To address this problem, after analyzing the national healthcare infrastructure along with the characteristics of emerging infectious diseases, we propose the revision of the relevant law(s) in terms of governance aspects, emergency medical countermeasure aspects, and the human rights aspect.

Infectious disease-related laws: prevention and control measures

PubMed Central

2017-01-01

OBJECTIVES This study examines recently revised Korean government legislation addressing global infectious disease control for public health emergency situations, with the aim of proposing more rational, effective and realistic interpretations and applications for improvement of law. METHODS The Korea reported its first laboratory-confirmed case of Middle East Respiratory Syndrome (MERS) coronavirus on May 20, 2015. Since the first indexed case, Korean public health authorities enforced many public health measures that were not authorized in the law; the scope of the current law was too limited to cover MERS. Korea has three levels of government: the central government, special self-governing provinces, and si/gun/gu. Unfortunately, the Infectious Disease Control and Prevention Act does not designate the specific roles of each level of government, and does not state how these governmental branches should be vertically integrated in a state of emergency. RESULTS When thinking about these policy questions, we should be especially concerned about introducing a new act that deals with all matters relevant to emerging infectious diseases. The aim would be to develop a structure that specifies the roles of each level of government, and facilitates the close collaboration among them, then enacting this in law for the prevention and response of infectious disease. CONCLUSIONS To address this problem, after analyzing the national healthcare infrastructure along with the characteristics of emerging infectious diseases, we propose the revision of the relevant law(s) in terms of governance aspects, emergency medical countermeasure aspects, and the human rights aspect. PMID:28774161

Digital flight control actuation system study

NASA Technical Reports Server (NTRS)

Rossing, R.; Hupp, R.

1974-01-01

Flight control actuators and feedback sensors suitable for use in a redundant digital flight control system were examined. The most appropriate design approach for an advanced digital flight control actuation system for development and use in a fly-by-wire system was selected. The concept which was selected consisted of a PM torque motor direct drive. The selected system is compatible with concurrent and independent development efforts on the computer system and the control law mechanizations.

Operation of Darrieus turbines in constant circulation framework

NASA Astrophysics Data System (ADS)

Gorle, J. M. R.; Chatellier, L.; Pons, F.; Ba, M.

2017-07-01

Analytical and computational studies of flow across a low-speed marine turbine of Darrieus type with pitching blades have been carried out for flowfield and performance evaluation. The objective of this study is to develop efficient blade pitching laws to arrest or control the vortex shedding from the blades during turbine's operation. This is achieved by imparting an arbitrary constant amount of circulation to the blades, where Kelvin's theorem is respected. This paper presents the extension of the application of conformal mapping to produce the time-dependent flow over a rotating turbine blade in order to develop a quantified relationship between the blade's orientation with respect to the rotor's tangent and its rotational motion. The flow development is based on the analytical treatment given to potential flow formulation through Laurent series decomposition, where the Kutta condition is satisfied. The pitch control law and the analytical modeling of the hydrodynamic forces acting on the blade are derived based on Kelvin's theorem for the conservation of circulation. The application of this pitch control law in the real flow conditions is however limited due to viscous losses and rotational effects. Therefore, a 2D computational fluid dynamics (CFD) study with the shear stress transport (SST) k -ω turbulence model has been performed to examine the flow across a 4-bladed turbine model. While validating the analytical work, the numerical investigation reveals the applicability and limitations of circulation-controlled blade pitching laws in real flow conditions. In particular, a reference equivalent angle of attack is defined, which must be contained in a tight range in order to effectively prevent vortex shedding at a given tip-speed ratio.

Input-output oriented computation algorithms for the control of large flexible structures

NASA Technical Reports Server (NTRS)

Minto, K. D.

1989-01-01

An overview is given of work in progress aimed at developing computational algorithms addressing two important aspects in the control of large flexible space structures; namely, the selection and placement of sensors and actuators, and the resulting multivariable control law design problem. The issue of sensor/actuator set selection is particularly crucial to obtaining a satisfactory control design, as clearly a poor choice will inherently limit the degree to which good control can be achieved. With regard to control law design, the researchers are driven by concerns stemming from the practical issues associated with eventual implementation of multivariable control laws, such as reliability, limit protection, multimode operation, sampling rate selection, processor throughput, etc. Naturally, the burden imposed by dealing with these aspects of the problem can be reduced by ensuring that the complexity of the compensator is minimized. Our approach to these problems is based on extensions to input/output oriented techniques that have proven useful in the design of multivariable control systems for aircraft engines. In particular, researchers are exploring the use of relative gain analysis and the condition number as a means of quantifying the process of sensor/actuator selection and placement for shape control of a large space platform.

Continuous Wheel Momentum Dumping Using Magnetic Torquers and Thrusters

NASA Astrophysics Data System (ADS)

Oh, Hwa-Suk; Choi, Wan-Sik; Eun, Jong-Won

1996-12-01

Two momentum management schemes using magnetic torquers and thrusters are sug-gested. The stability of the momentum dumping logic is proved at a general attitude equilibrium. Both momentum dumping control laws are implemented with Pulse-Width- Pulse-Frequency Modulated on-off control, and shown working equally well with the original continuous and variable strength control law. Thrusters are assummed to be asymmetrically configured as a contingency case. Each thruster is fired following separated control laws rather than paired thrusting. Null torque thrusting control is added on the thrust control calculated from the momentum control law for the gener-ation of positive thrusting force. Both magnetic and thrusting control laws guarantee the momentum dumping, however, the wheel inner loop control is needed for the "wheel speed" dumping, The control laws are simulated on the KOrea Multi-Purpose SATellite (KOMPSAT) model.

Integrated Control System Engineering Support.

DTIC Science & Technology

1984-12-01

interference susceptibility. " Study multiplex bus loading requirements. Flight Control Software 0 " Demonstrate efficiencies of modular software and...Major technical thrusts include the development of: (a) task-tailored mutimode con- trol laws incorporating direct force and weapon line pointing

Political commitment to tuberculosis control in Ghana.

PubMed

Amo-Adjei, Joshua

2014-01-01

As part of expanding and sustaining tuberculosis (TB) control, the Stop TB Partnership of the World Health Organization initiative has called for strong political commitment to TB control, particularly in developing countries. Framing political commitment within the theoretical imperatives of the political economy of health, this study explores the existing and the expected dimensions of political commitment to TB control in Ghana. Semi-structured in-depth interviews were conducted with 29 purposively selected staff members of the Ghana Health Service and some political officeholders. In addition, the study analysed laws, policies and regulations relevant to TB control. Four dimensions of political commitment emerged from the interviews: provision of adequate resources (financial, human and infrastructural); political authorities' participation in advocacy for TB; laws and policies' promulgation and social protection interventions. Particularly in respect to financial resources, donors such as the Global Fund to Fight AIDS, Tuberculosis and Malaria presently give more than 60% of the working budget of the programme. The documentary review showed that laws, policies and regulations existed that were relevant to TB control, albeit they were not clearly linked.

A design procedure for the handling qualities optimization of the X-29A aircraft

NASA Technical Reports Server (NTRS)

Bosworth, John T.; Cox, Timothy H.

1989-01-01

A design technique for handling qualities improvement was developed for the X-29A aircraft. As with any new aircraft, the X-29A control law designers were presented with a relatively high degree of uncertainty in their mathematical models. The presence of uncertainties, and the high level of static instability of the X-29A caused the control law designers to stress stability and robustness over handling qualities. During flight test, the mathematical models of the vehicle were validated or corrected to match the vehicle dynamic behavior. The updated models were then used to fine tune the control system to provide fighter-like handling characteristics. A design methodology was developed which works within the existing control system architecture to provide improved handling qualities and acceptable stability with a minimum of cost in both implementation as well as software verification and validation.

Energy efficient motion control of the electric bus on route

NASA Astrophysics Data System (ADS)

Kotiev, G. O.; Butarovich, D. O.; Kositsyn, B. B.

2018-02-01

At present, the urgent problem is the reduction of energy costs of urban motor transport. The article proposes a method of solving this problem by developing an energy-efficient law governing the movement of an electric bus along a city route. To solve this problem, an algorithm is developed based on the dynamic programming method. The proposed method allows you to take into account the constraints imposed on the phase coordinates, control action, as well as on the time of the route. In the course of solving the problem, the model of rectilinear motion of an electric bus on a horizontal reference surface is considered, taking into account the assumptions that allow it to be adapted for the implementation of the method. For the formation of a control action in the equations of motion dynamics, an algorithm for changing the traction / braking torque on the wheels of an electric bus is considered, depending on the magnitude of the control parameter and the speed of motion. An optimal phase trajectory was obtained on a selected section of the road for the prototype of an electric bus. The article presents the comparison of simulation results obtained with the optimal energy efficient control law with the results obtained by a test driver. The comparison proved feasibility of the energy efficient control law for the automobile city electric transport.

Design Specification for a Thrust-Vectoring, Actuated-Nose-Strake Flight Control Law for the High-Alpha Research Vehicle

NASA Technical Reports Server (NTRS)

Bacon, Barton J.; Carzoo, Susan W.; Davidson, John B.; Hoffler, Keith D.; Lallman, Frederick J.; Messina, Michael D.; Murphy, Patrick C.; Ostroff, Aaron J.; Proffitt, Melissa S.; Yeager, Jessie C.;

Control Law-Control Allocation Interaction: F/A-18 PA Simulation Test - Bed

NASA Technical Reports Server (NTRS)

Durham, Wayne; Nelson, Mark

2001-01-01

This report documents the first stage of research into Control Law - Control Allocation Interactions. A three-year research effort was originally proposed: 1. Create a desktop flight simulation environment under which experiments related to the open questions may be conducted. 2. Conduct research to determine which aspects of control allocation have impact upon control law design that merits further research. 3. Conduct research into those aspects of control allocation identified above, and their impacts upon control law design. Simulation code was written utilizing the F/A-18 airframe in the power approach (PA) configuration. A dynamic inversion control law was implemented and used to drive a state-of-the-art control allocation subroutine.

Monitoring and Control Interface Based on Virtual Sensors

PubMed Central

Escobar, Ricardo F.; Adam-Medina, Manuel; García-Beltrán, Carlos D.; Olivares-Peregrino, Víctor H.; Juárez-Romero, David; Guerrero-Ramírez, Gerardo V.

2014-01-01

In this article, a toolbox based on a monitoring and control interface (MCI) is presented and applied in a heat exchanger. The MCI was programed in order to realize sensor fault detection and isolation and fault tolerance using virtual sensors. The virtual sensors were designed from model-based high-gain observers. To develop the control task, different kinds of control laws were included in the monitoring and control interface. These control laws are PID, MPC and a non-linear model-based control law. The MCI helps to maintain the heat exchanger under operation, even if a temperature outlet sensor fault occurs; in the case of outlet temperature sensor failure, the MCI will display an alarm. The monitoring and control interface is used as a practical tool to support electronic engineering students with heat transfer and control concepts to be applied in a double-pipe heat exchanger pilot plant. The method aims to teach the students through the observation and manipulation of the main variables of the process and by the interaction with the monitoring and control interface (MCI) developed in LabVIEW©. The MCI provides the electronic engineering students with the knowledge of heat exchanger behavior, since the interface is provided with a thermodynamic model that approximates the temperatures and the physical properties of the fluid (density and heat capacity). An advantage of the interface is the easy manipulation of the actuator for an automatic or manual operation. Another advantage of the monitoring and control interface is that all algorithms can be manipulated and modified by the users. PMID:25365462

Rotor-state feedback in the design of flight control laws for a hovering helicopter

NASA Technical Reports Server (NTRS)

Takahashi, Marc D.

1994-01-01

The use of rigid-body and rotor-state feedback gains in the design of helicopter flight control laws was investigated analytically on a blade element, articulated rotor, helicopter model. The study was conducted while designing a control law to meet an existing military rotorcraft handling qualities design specification (ADS-33C) in low-speed flight. A systematic approach to meet this specification was developed along with an assessment of the function of these gains in the feedback loops. Using the results of this assessment, the pitch and roll crossover behavior was easily modified by adjusting the body attitude and rotor-flap feedback gains. Critical to understanding the feedback gains is that the roll and pitch rate dynamics each have second-order behavior, not the classic first-order behavior, which arises from a quasi-static rotor, six degree-of-freedom model.

Patterns of drug trafficking and countermeasures: the personal view of a veteran.

PubMed

Price, B

1992-01-01

In the present paper, a law enforcement official with nearly 40 years of experience in combating drug trafficking provides insight that may prove useful to persons in other organizations and/or cultures. He examines, in particular, the development, at the national level, of drug control legislation, a drug law enforcement strategy and a drug intelligence unit.

Force Protection via UGV-UAV Collaboration: Development of Control Law for Vision Based Target Tracking on SUAV

DTIC Science & Technology

2007-12-01

Hardware - In - Loop , Piccolo, UAV, Unmanned Aerial Vehicle 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT...Maneuvering Target.......................... 35 C. HARDWARE - IN - LOOP SIMULATION............................................... 37 1. Hardware - In - Loop Setup...law as proposed in equation (23) is capable of tracking a maneuvering target. C. HARDWARE - IN - LOOP SIMULATION The intention of HIL simulation

Piloted Evaluation of Modernized Limited Authority Control Laws in the NASA-Ames Vertical Motion Simulator (VMS)

NASA Technical Reports Server (NTRS)

Sahasrabudhe, Vineet; Melkers, Edgar; Faynberg, Alexander; Blanken, Chris L.

2003-01-01

The UH-60 BLACK HAWK was designed in the 1970s, when the US Army primarily operated during the day in good visual conditions. Subsequently, the introduction of night-vision goggles increased the BLACK HAWK'S mission effectiveness, but the accident rate also increased. The increased accident rate is strongly tied to increased pilot workload as a result of a degradation in visual cues. Over twenty years of research in helicopter flight control and handling qualities has shown that these degraded handling qualities can be recovered by modifying the response type of the helicopter in low speed flight. Sikorsky Aircraft Corporation initiated a project under the National Rotorcraft Technology Center (NRTC) to develop modern flight control laws while utilizing the existing partial authority Stability Augmentation System (SAS) of the BLACK HAWK. This effort resulted in a set of Modernized Control Laws (MCLAWS) that incorporate rate command and attitude command response types. Sikorsky and the US Army Aeroflightdynamics Directorate (AFDD) conducted a piloted simulation on the NASA-Ames Vertical h4otion Simulator, to assess potential handling qualities and to reduce the risk of subsequent implementation and flight test of these modern control laws on AFDD's EH-60L helicopter. The simulation showed that Attitude Command Attitude Hold control laws in pitch and roll improve handling qualities in the low speed flight regime. These improvements are consistent across a range of mission task elements and for both good and degraded visual environments. The MCLAWS perform better than the baseline UH-60A control laws in the presence of wind and turbulence. Finally, while the improved handling qualities in the pitch and roll axis allow the pilot to pay more attention to the vertical axis and hence altitude performance also improves, it is clear from pilot comments and altitude excursions that the addition of an Altitude Hold function would further reduce workload and improve overall handling qualities of the aircraft.

FCTC Implementation in Nigeria: Lessons for Low and Middle-Income Countries.

PubMed

Egbe, Catherine O; Bialous, Stella A; Glantz, Stanton

2018-04-06

Nigeria is a significant tobacco market and influential country in Africa. Nigeria ratified the WHO Framework Convention on Tobacco Control (FCTC) in 2005. We reviewed Nigeria's tobacco control legislation since 2000 and compliance of the National Tobacco Control Act (NTCA) 2015 with the FCTC. We reviewed the National Tobacco Control Bills 2011 (proposed by legislature) and 2014 (proposed by Executive), the NTCA 2015, and media stories on tobacco control from 2008 to 2017. The NTCA, despite being more comprehensive than Nigeria's first Tobacco Smoking (Control) law of 1990, maintained provisions promoted by the tobacco industry. Examples include: allowing designated smoking areas in hospitality venues, higher educational institutions, and transportation venues; a loophole in the advertising restictions allowing communications with consenting adults; having the Manufacturers Association of Nigeria (MAN) (which includes tobacco companies) on the National Tobacco Control Committee charged with working with the Ministry of Health to implement the law. The industry is also directly involved with the Standards Organisation of Nigeria (SON) in preparing regulations on cigarette constituents and emissions. In an unprecedented step globally, the law requires that implementing regulations be approved by the National Assembly, giving the industry another opportunity to weaken this law further by lobbying the legislators to favour the industry. As of January 2018 the law was still not being enforced. The NTCA can be strengthened through implementation guidelines still being developed. The industry should be prevented from interfering with through MAN and SON, as required by FCTC Article 5.3. The tobacco industry works to block FCTC implementation even after a country ratifies the treaty. The Nigerian case illustrates that it is essential for health authorities to remain vigilant and ensure that the tobacco industry does not play a decision-making role in the process of tobacco legislation and regulation either directly or indirectly. The unprecedented step of requiring approval of implementing regulations for the Nigerian law should not be allowed to become a precedent in other countries.

Digital robust active control law synthesis for large order systems using constrained optimization

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

1987-01-01

This paper presents a direct digital control law synthesis procedure for a large order, sampled data, linear feedback system using constrained optimization techniques to meet multiple design requirements. A linear quadratic Gaussian type cost function is minimized while satisfying a set of constraints on the design loads and responses. General expressions for gradients of the cost function and constraints, with respect to the digital control law design variables are derived analytically and computed by solving a set of discrete Liapunov equations. The designer can choose the structure of the control law and the design variables, hence a stable classical control law as well as an estimator-based full or reduced order control law can be used as an initial starting point. Selected design responses can be treated as constraints instead of lumping them into the cost function. This feature can be used to modify a control law, to meet individual root mean square response limitations as well as minimum single value restrictions. Low order, robust digital control laws were synthesized for gust load alleviation of a flexible remotely piloted drone aircraft.

Real-time path planning and autonomous control for helicopter autorotation

NASA Astrophysics Data System (ADS)

Yomchinda, Thanan

Autorotation is a descending maneuver that can be used to recover helicopters in the event of total loss of engine power; however it is an extremely difficult and complex maneuver. The objective of this work is to develop a real-time system which provides full autonomous control for autorotation landing of helicopters. The work includes the development of an autorotation path planning method and integration of the path planner with a primary flight control system. The trajectory is divided into three parts: entry, descent and flare. Three different optimization algorithms are used to generate trajectories for each of these segments. The primary flight control is designed using a linear dynamic inversion control scheme, and a path following control law is developed to track the autorotation trajectories. Details of the path planning algorithm, trajectory following control law, and autonomous autorotation system implementation are presented. The integrated system is demonstrated in real-time high fidelity simulations. Results indicate feasibility of the capability of the algorithms to operate in real-time and of the integrated systems ability to provide safe autorotation landings. Preliminary simulations of autonomous autorotation on a small UAV are presented which will lead to a final hardware demonstration of the algorithms.

A case study for the real-time experimental evaluation of the VIPER microprocessor

NASA Astrophysics Data System (ADS)

Carreno, Victor A.; Angellatta, Rob K.

1991-09-01

An experiment to evaluate the applicability of the Verifiable Integrated Processor for Enhanced Reliability (VIPER) microprocessor to real time control is described. The VIPER microprocessor was invented by the Royal Signals and Radar Establishment (RSRE), U.K., and is an example of the use of formal mathematical methods for developing electronic digital systems with a high degree of assurance on the system design and implementation correctness. The experiment consisted of selecting a control law, writing the control law algorithm for the VIPER processor, and providing real time, dynamic inputs into the processor and monitoring the outputs. The control law selected and coded for the VIPER processor was the yaw damper function of an automatic landing program for a 737 aircraft. The mechanisms for interfacing the VIPER Single Board Computer to the VAX host are described. Results include run time experiences, performance evaluation, and comparison of VIPER and FORTRAN yaw damper algorithm output for accuracy estimation.

A case study for the real-time experimental evaluation of the VIPER microprocessor

NASA Technical Reports Server (NTRS)

Carreno, Victor A.; Angellatta, Rob K.

1991-01-01

An experiment to evaluate the applicability of the Verifiable Integrated Processor for Enhanced Reliability (VIPER) microprocessor to real time control is described. The VIPER microprocessor was invented by the Royal Signals and Radar Establishment (RSRE), U.K., and is an example of the use of formal mathematical methods for developing electronic digital systems with a high degree of assurance on the system design and implementation correctness. The experiment consisted of selecting a control law, writing the control law algorithm for the VIPER processor, and providing real time, dynamic inputs into the processor and monitoring the outputs. The control law selected and coded for the VIPER processor was the yaw damper function of an automatic landing program for a 737 aircraft. The mechanisms for interfacing the VIPER Single Board Computer to the VAX host are described. Results include run time experiences, performance evaluation, and comparison of VIPER and FORTRAN yaw damper algorithm output for accuracy estimation.

Control Law for Automatic Landing Using Fuzzy-Logic Control

NASA Astrophysics Data System (ADS)

Kato, Akio; Inagaki, Yoshiki

The effectiveness of a fuzzy-logic control law for automatically landing an aircraft that handles both the control to lead an aircraft from horizontal flight at an altitude of 500 meters to flight along the glide-path course near the runway, as well as the control to direct the aircraft to land smoothly on a runway, was investigated. The control law for the automatic landing was designed to match the design goals of directing an aircraft from horizontal flight to flight along a glide-path course quickly and smoothly, and for landing smoothly on a runway. The design of the control law and evaluation of the control performance were performed considering the ground effect at landing. As a result, it was confirmed that the design goals were achieved. Even if the characteristics of the aircraft change greatly, the proposed control law is able to maintain the control performance. Moreover, it was confirmed to be able to land an aircraft safely during air turbulence. The present paper indicates that fuzzy-logic control is an effective and flexible method when applied to the control law for automatic landing, and the design method of the control law using fuzzy-logic control was obtained.

Control Law for Automatic Landing Using Fuzzy Logic Control

NASA Astrophysics Data System (ADS)

Kato, Akio; Inagaki, Yoshiki

The effectiveness of fuzzy logic control law for automatic landing of aircraft, which cover both of control to lead aircraft from level flight at an altitude of 500m to the flight on the glide-path course near the runway and control for the aircraft to land smoothly on a runway, was studied. The control law of the automatic landing was designed to match the design goals of leading from the horizontal flight to the flight on the glide-path course quickly and smoothly and of landing smoothly on a runway. Because there is the ground effect at landing, design of control law and evaluation of control performance were done in consideration of the ground effect. As a result, it was confirmed that the design objective was achieved. Even if the characteristics of the plant changes greatly, this control law was able to maintain the control performance. Moreover, it was confirmed to be able to land safely when there was air turbulence. This paper shows that fuzzy logic control is an effective and flexible method when applied to control law for automatic landing and the design method of control law using fuzzy logic control was obtained.

Robust optimal control of material flows in demand-driven supply networks

NASA Astrophysics Data System (ADS)

Laumanns, Marco; Lefeber, Erjen

2006-04-01

We develop a model based on stochastic discrete-time controlled dynamical systems in order to derive optimal policies for controlling the material flow in supply networks. Each node in the network is described as a transducer such that the dynamics of the material and information flows within the entire network can be expressed by a system of first-order difference equations, where some inputs to the system act as external disturbances. We apply methods from constrained robust optimal control to compute the explicit control law as a function of the current state. For the numerical examples considered, these control laws correspond to certain classes of optimal ordering policies from inventory management while avoiding, however, any a priori assumptions about the general form of the policy.

Development of Aeroservoelastic Analytical Models and Gust Load Alleviation Control Laws of a SensorCraft Wind-Tunnel Model Using Measured Data

NASA Technical Reports Server (NTRS)

Silva, Walter A.; Vartio, Eric; Shimko, Anthony; Kvaternik, Raymond G.; Eure, Kenneth W.; Scott,Robert C.

2007-01-01

Aeroservoelastic (ASE) analytical models of a SensorCraft wind-tunnel model are generated using measured data. The data was acquired during the ASE wind-tunnel test of the HiLDA (High Lift-to-Drag Active) Wing model, tested in the NASA Langley Transonic Dynamics Tunnel (TDT) in late 2004. Two time-domain system identification techniques are applied to the development of the ASE analytical models: impulse response (IR) method and the Generalized Predictive Control (GPC) method. Using measured control surface inputs (frequency sweeps) and associated sensor responses, the IR method is used to extract corresponding input/output impulse response pairs. These impulse responses are then transformed into state-space models for use in ASE analyses. Similarly, the GPC method transforms measured random control surface inputs and associated sensor responses into an AutoRegressive with eXogenous input (ARX) model. The ARX model is then used to develop the gust load alleviation (GLA) control law. For the IR method, comparison of measured with simulated responses are presented to investigate the accuracy of the ASE analytical models developed. For the GPC method, comparison of simulated open-loop and closed-loop (GLA) time histories are presented.

Development of Aeroservoelastic Analytical Models and Gust Load Alleviation Control Laws of a SensorCraft Wind-Tunnel Model Using Measured Data

NASA Technical Reports Server (NTRS)

Silva, Walter A.; Shimko, Anthony; Kvaternik, Raymond G.; Eure, Kenneth W.; Scott, Robert C.

2006-01-01

Aeroservoelastic (ASE) analytical models of a SensorCraft wind-tunnel model are generated using measured data. The data was acquired during the ASE wind-tunnel test of the HiLDA (High Lift-to-Drag Active) Wing model, tested in the NASA Langley Transonic Dynamics Tunnel (TDT) in late 2004. Two time-domain system identification techniques are applied to the development of the ASE analytical models: impulse response (IR) method and the Generalized Predictive Control (GPC) method. Using measured control surface inputs (frequency sweeps) and associated sensor responses, the IR method is used to extract corresponding input/output impulse response pairs. These impulse responses are then transformed into state-space models for use in ASE analyses. Similarly, the GPC method transforms measured random control surface inputs and associated sensor responses into an AutoRegressive with eXogenous input (ARX) model. The ARX model is then used to develop the gust load alleviation (GLA) control law. For the IR method, comparison of measured with simulated responses are presented to investigate the accuracy of the ASE analytical models developed. For the GPC method, comparison of simulated open-loop and closed-loop (GLA) time histories are presented.

Cooperative control theory and integrated flight and propulsion control

NASA Technical Reports Server (NTRS)

Schmidt, David K.; Schierman, John D.

1995-01-01

The major contribution of this research was the exposition of the fact that airframe and engine interactions could be present, and their effects could include loss of stability and performance of the control systems. Also, the significance of two directional, as opposed to one-directional, coupling was identified and explained. A multivariable stability and performance analysis methodology was developed, and applied to several candidate aircraft configurations. In these example evaluations, the significance of these interactions was underscored. Also exposed was the fact that with interactions present along with some integrated control approaches, the engine command/limiting logic (which represents an important nonlinear component of the engine control system) can impact closed-loop airframe/engine system stability. Finally, a brief investigation of control-law synthesis techniques appropriate for the class of systems was pursued, and it was determined that multivariable techniques, including model-following formulations of LQG and/or H infinity methods, showed promise. However, for practical reasons, decentralized control architectures are preferred, which is an architecture incompatible with these synthesis methods. The major contributions of the second phase of the grant was the development of conditions under which no decentralized controller could achieve closed loop system requirements on stability and/or performance. Sought were conditions that depended only on properties of the plant and the requirement, and independent of any particular control law or synthesis approach. Therefore, they could be applied a priori, before synthesis of a candidate control law. Under this grant, such conditions were found regarding stability, and encouraging initial results were obtained regarding performance.

The future of EUV lithography: enabling Moore's Law in the next decade

NASA Astrophysics Data System (ADS)

Pirati, Alberto; van Schoot, Jan; Troost, Kars; van Ballegoij, Rob; Krabbendam, Peter; Stoeldraijer, Judon; Loopstra, Erik; Benschop, Jos; Finders, Jo; Meiling, Hans; van Setten, Eelco; Mika, Niclas; Dredonx, Jeannot; Stamm, Uwe; Kneer, Bernhard; Thuering, Bernd; Kaiser, Winfried; Heil, Tilmann; Migura, Sascha

2017-03-01

While EUV systems equipped with a 0.33 Numerical Aperture lenses are readying to start volume manufacturing, ASML and Zeiss are ramping up their development activities on a EUV exposure tool with Numerical Aperture greater than 0.5. The purpose of this scanner, targeting a resolution of 8nm, is to extend Moore's law throughout the next decade. A novel, anamorphic lens design, has been developed to provide the required Numerical Aperture; this lens will be paired with new, faster stages and more accurate sensors enabling Moore's law economical requirements, as well as the tight focus and overlay control needed for future process nodes. The tighter focus and overlay control budgets, as well as the anamorphic optics, will drive innovations in the imaging and OPC modelling, and possibly in the metrology concepts. Furthermore, advances in resist and mask technology will be required to image lithography features with less than 10nm resolution. This paper presents an overview of the key technology innovations and infrastructure requirements for the next generation EUV systems.

Searching the Future for the Legal Regime of Space Activities: the Need for Unification of National Space Legislation' Provisions

NASA Astrophysics Data System (ADS)

Negoda, S. A.

2002-01-01

space activities. For the future legal regime of space activities it is vital to preserve the existed principles and main provisions of the international space law. related legislations are developing rapidly. They become serious instrument for legal regulation of space activities. those projects with a foreign party involvement. Quite often partners in international space projects agree to choice a domestic law of one of them. They do this for defining a certain organizational and/or contractual issue (disputes settlement, for example) of the project. that such practice will spread widely. could help to preserve the existed important provisions of international space law (responsibility of states for their national activities, for instance). development of international space private law. We believe that solely special laws and regulations of national legislations could not regulate modern space activities. Being more and more commercial, space activities are becoming a real part of "downed to Earth" commercial activities. Therefore, in many countries provisions of civil, commercial, investment and other branches of national law are applied to such activities. which could low possible risks of such activities and to control them. Such unification seems to be suitable in the following fields: 1)implementation of provisions of international space law in national space laws; 2)definition of unified terminology, accepted by national laws of all parties; 3)unification in national legislations of a certain standards (insurance rates and rules, for instance); 4)unification in national laws of issues related to liability (for instance, a mutual wave of liability in certain types of 5)implementation in national laws of unified rules and procedures of space-related commercial disputes settlement; 6)unification of mechanisms for protection of space-related intellectual property. unification of their provisions. Special attention is paid to provisions of private law (including collision norms). conflicts between parties and national laws in light of expanding of application of national laws' provisions to space activities, 2) unification and further development of international space private law will help to maintain the authority of international public space law and to keep a proper hierarchy between these branches.

Gust alleviation - Criteria and control laws

NASA Technical Reports Server (NTRS)

Rynaski, E. G.

1979-01-01

The relationships between criteria specified for aircraft gust alleviation and the form of the control laws that result from the criteria are considered. Open-loop gust alleviation based on the linearized, small perturbation equations of aircraft motion is discussed, and an approximate solution of the open-loop control law is presented for the case in which the number of degrees of freedom of the aircraft exceeds the rank of the control effectiveness matrix. Excessive actuator lag is compensated for by taking into account actuator dynamics in the equations of motion, resulting in the specification of a general load network. Criteria for gust alleviation when output motions are gust alleviated and the closed-loop control law derived from them are examined and linear optimal control law is derived. Comparisons of the control laws reveal that the effectiveness of an open-loop control law is greatest at low aircraft frequencies but deteriorates as the natural frequency of the actuators is approached, while closed-loop methods are found to be more effective at higher frequencies.

Popping the balloon effect: assessing drug law enforcement in terms of displacement, diffusion, and the containment hypothesis.

PubMed

Windle, James; Farrell, Graham

2012-01-01

The "balloon effect" is an often used but rather dismissive representation of the effects of drug law enforcement. It implies a hydraulic displacement model and an impervious illicit drug trade. This paper reviews theoretical and empirical developments in policing and crime prevention. Based on this, 10 types of displacement are identified and four arguments developed: (1) Displacement is less extensive and harmful than often contended; (2) Where displacement may occur it preferably should be exploited as a policy tool to delay the illicit drug industry and deflect it to less harmful locations and forms; (3) The opposite of displacement occurs, termed a diffusion of drug control benefits, wherein law enforcement has benefits that extend further than envisaged, and has 10 types mirroring those of displacement; (4) The net impact of drug law enforcement is often underestimated, and a containment hypothesis may offer a more accurate framework for evaluation.

A minimum attention control law for ball catching.

PubMed

Jang, Cheongjae; Lee, Jee-eun; Lee, Sohee; Park, F C

2015-10-06

Digital implementations of control laws typically involve discretization with respect to both time and space, and a control law that can achieve a task at coarser levels of discretization can be said to require less control attention, and also reduced implementation costs. One means of quantitatively capturing the attention of a control law is to measure the rate of change of the control with respect to changes in state and time. In this paper we present an attention-minimizing control law for ball catching and other target tracking tasks based on Brockett's attention criterion. We first highlight the connections between this attention criterion and some well-known principles from human motor control. Under the assumption that the optimal control law is the sum of a linear time-varying feedback term and a time-varying feedforward term, we derive an LQR-based minimum attention tracking control law that is stable, and obtained efficiently via a finite-dimensional optimization over the symmetric positive-definite matrices. Taking ball catching as our primary task, we perform numerical experiments comparing the performance of the various control strategies examined in the paper. Consistent with prevailing theories about human ball catching, our results exhibit several familiar features, e.g., the transition from open-loop to closed-loop control during the catching movement, and improved robustness to spatiotemporal discretization. The presented control laws are applicable to more general tracking problems that are subject to limited communication resources.

Development and flight evaluation of an augmented stability active controls concept with a small horizontal tail

NASA Technical Reports Server (NTRS)

Rising, J. J.; Kairys, A. A.; Maass, C. A.; Siegart, C. D.; Rakness, W. L.; Mijares, R. D.; King, R. W.; Peterson, R. S.; Hurley, S. R.; Wickson, D.

1982-01-01

A limited authority pitch active control system (PACS) was developed for a wide body jet transport (L-1011) with a flying horizontal stabilizer. Two dual channel digital computers and the associated software provide command signals to a dual channel series servo which controls the stabilizer power actuators. Input sensor signals to the computer are pitch rate, column-trim position, and dynamic pressure. Control laws are given for the PACS and the system architecture is defined. The piloted flight simulation and vehicle system simulation tests performed to verify control laws and system operation prior to installation on the aircraft are discussed. Modifications to the basic aircraft are described. Flying qualities of the aircraft with the PACS on and off were evaluated. Handling qualities for cruise and high speed flight conditions with the c.g. at 39% mac ( + 1% stability margin) and PACS operating were judged to be as good as the handling qualities with the c.g. at 25% (+15% stability margin) and PACS off.

Sensitivity method for integrated structure/active control law design

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.

1987-01-01

The development is described of an integrated structure/active control law design methodology for aeroelastic aircraft applications. A short motivating introduction to aeroservoelasticity is given along with the need for integrated structures/controls design algorithms. Three alternative approaches to development of an integrated design method are briefly discussed with regards to complexity, coordination and tradeoff strategies, and the nature of the resulting solutions. This leads to the formulation of the proposed approach which is based on the concepts of sensitivity of optimum solutions and multi-level decompositions. The concept of sensitivity of optimum is explained in more detail and compared with traditional sensitivity concepts of classical control theory. The analytical sensitivity expressions for the solution of the linear, quadratic cost, Gaussian (LQG) control problem are summarized in terms of the linear regulator solution and the Kalman Filter solution. Numerical results for a state space aeroelastic model of the DAST ARW-II vehicle are given, showing the changes in aircraft responses to variations of a structural parameter, in this case first wing bending natural frequency.

Dynamics and control of tethered antennas/reflectors in orbit

NASA Astrophysics Data System (ADS)

Liu, Liangdong; Bainum, Peter M.

The system linear equations for the motion of a tethered shallow spherical shell in orbit with its symmetry axis nominally following the local vertical are developed. The shell roll, yaw, tether out-of-plane swing motion and elastic vibrations are decoupled from the shell and tether in-plane pitch motions and elastic vibrations. The neutral gravity stability conditions for the special case of a constant length rigid tether are given for in-plane motion and out-of-plant motion. It is proved that the in-plane motion of the system could be asymptotically stable based on Rupp's tension control law, for a variable length tether. However, the system simulation results indicate that the transient responses can be improved significantly, especially for the damping of the tether and shell pitch motion, by an optimal feedback control law for the rigid variable length tether model. It is also seen that the system could be unstable when the effect of tether flexibility is included if the control gains are not chosen carefully. The transient responses for three different tension control laws are compared during typical station keeping operations.

Nonlinear Dynamic Inversion Baseline Control Law: Flight-Test Results for the Full-scale Advanced Systems Testbed F/A-18 Airplane

NASA Technical Reports Server (NTRS)

Miller, Christopher J.

2011-01-01

A model reference nonlinear dynamic inversion control law has been developed to provide a baseline controller for research into simple adaptive elements for advanced flight control laws. This controller has been implemented and tested in a hardware-in-the-loop simulation and in flight. The flight results agree well with the simulation predictions and show good handling qualities throughout the tested flight envelope with some noteworthy deficiencies highlighted both by handling qualities metrics and pilot comments. Many design choices and implementation details reflect the requirements placed on the system by the nonlinear flight environment and the desire to keep the system as simple as possible to easily allow the addition of the adaptive elements. The flight-test results and how they compare to the simulation predictions are discussed, along with a discussion about how each element affected pilot opinions. Additionally, aspects of the design that performed better than expected are presented, as well as some simple improvements that will be suggested for follow-on work.

A Flight Control System Architecture for the NASA AirSTAR Flight Test Infrastructure

NASA Technical Reports Server (NTRS)

Murch, Austin M.

2008-01-01

A flight control system architecture for the NASA AirSTAR infrastructure has been designed to address the challenges associated with safe and efficient flight testing of research control laws in adverse flight conditions. The AirSTAR flight control system provides a flexible framework that enables NASA Aviation Safety Program research objectives, and includes the ability to rapidly integrate and test research control laws, emulate component or sensor failures, inject automated control surface perturbations, and provide a baseline control law for comparison to research control laws and to increase operational efficiency. The current baseline control law uses an angle of attack command augmentation system for the pitch axis and simple stability augmentation for the roll and yaw axes.

A system for spacecraft attitude control and energy storage

NASA Technical Reports Server (NTRS)

Shaughnessy, J. D.

1974-01-01

A conceptual design for a double-gimbal reaction-wheel energy-wheel device which has three-axis attitude control and electrical energy storage capability is given. A mathematical model for the three-axis gyroscope (TAG) was developed, and a system of multiple units is proposed for attitude control and energy storage for a class of spacecraft. Control laws were derived to provide the required attitude-control torques and energy transfer while minimizing functions of TAG gimbal angles, gimbal rates, reaction-wheel speeds, and energy-wheel speed differences. A control law is also presented for a magnetic torquer desaturation system. A computer simulation of a three-TAG system for an orbiting telescope was used to evaluate the concept. The results of the study indicate that all control and power requirements can be satisfied by using the TAG concept.

Integrated modeling and analysis of a space-truss article

NASA Technical Reports Server (NTRS)

Stockwell, Alan E.; Perez, Sharon E.; Pappa, Richard S.

1990-01-01

MSC/NASTRAN is being used in the Controls-Structures Interaction (CSI) program at NASA Langley Research Center as a key analytical tool for structural analysis as well as the basis for control law development, closed-loop performance evaluation, and system safety checks. Guest investigators from academia and industry are performing dynamics and control experiments on a flight-like deployable space truss called Mini-Mast to determine the effectiveness of various active-vibration control laws. MSC/NASTRAN was used to calculate natural frequencies and mode shapes below 100 Hz to describe the dynamics of the 20-meter-long lightweight Mini-Mast structure. Gravitational effects contribute significantly to structural stiffness and are accounted for through a two-phase solution in which the differential stiffness matrix is calculated and then used in the eigensolution. Reduced modal models are extracted for control law design and evaluation of closed-loop system performance. Predicted actuator forces from controls simulations are then applied to the extended model to predict member loads and stresses. These pre-test analyses reduce risks associated with the structural integrity of the test article, which is a major concern in closed-loop control experiments due to potential instabilities.

Programme development of drug abuse control in Baluchistan, Pakistan.

PubMed

Zaidi, S M; Ashraf, S M; Afridi, A A

1982-01-01

The drug abuse control programme in Baluchistan is inter-disciplinary and progressive. Its main thrust consists of constant vigilance on border check-points by law enforcement agencies, developing in-patient and out-patient facilities for treatment and rehabilitation of addicted persons, and a preventive education programme using the mass media and students from higher educational institutions.

Implications of international law for the treatment of cancer: the Single Convention on Narcotic Drugs and the TRIPS Agreement.

PubMed

Liberman, J

2011-12-01

The development, manufacture, trade and distribution of medicines all take place within a web of international legal obligations that states have accepted under a range of multilateral, plurilateral and bilateral agreements. International law can operate either to facilitate or hinder access, depending on how it is developed and implemented. This article examines two areas of international law that are relevant to cancer treatment: the international drug control system, which regulates opioid analgesics; and the World Trade Organization's Trade-Related Aspects of Intellectual Property Agreement. This article outlines recent developments in relation to both, including in the activities of the Vienna-based agencies that collectively oversee the implementation of the Single Convention on Narcotic Drugs, and in the negotiation of the recent United Nations General Assembly Political Declaration on Non-communicable Diseases. While underlining the importance of law, this article notes that battles over law should not distract from the importance of other essential efforts to enhance access to medicines within the context of the strengthening of health systems. Copyright © 2011 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.

Progress in multirate digital control system design

NASA Technical Reports Server (NTRS)

Berg, Martin C.; Mason, Gregory S.

1991-01-01

A new methodology for multirate sampled-data control design based on a new generalized control law structure, two new parameter-optimization-based control law synthesis methods, and a new singular-value-based robustness analysis method are described. The control law structure can represent multirate sampled-data control laws of arbitrary structure and dynamic order, with arbitrarily prescribed sampling rates for all sensors and update rates for all processor states and actuators. The two control law synthesis methods employ numerical optimization to determine values for the control law parameters. The robustness analysis method is based on the multivariable Nyquist criterion applied to the loop transfer function for the sampling period equal to the period of repetition of the system's complete sampling/update schedule. The complete methodology is demonstrated by application to the design of a combination yaw damper and modal suppression system for a commercial aircraft.

Safe haven laws as crime control theater.

PubMed

Hammond, Michelle; Miller, Monica K; Griffin, Timothy

2010-07-01

This article examines safe haven laws, which allow parents to legally abandon their infants. The main objective is to determine whether safe haven laws fit the criteria of crime control theater, a term used to describe public policies that produce the appearance, but not the effect, of crime control, and as such are essentially socially constructed "solutions" to socially constructed crime "problems." The analysis will apply the principles of crime control theater to safe haven laws. Specifically, the term crime control theater applies to laws that are reactionary responses to perceived criminal threats and are often widely supported as a way to address the crime in question. Such laws are attractive because they appeal to mythic narratives (i.e., saving an innocent child from a predator); however they are likely ineffective due to the complexity of the crime. These laws can have deleterious effects when policymakers make false claims of success and stunt public discourse (e.g., drawing attention away from more frequent and preventable crimes). This analysis applies these criteria to safe haven laws to determine whether such laws can be classified as crime control theater. Many qualities inherent to crime control theater are present in safe haven laws. For example, the laws are highly publicized, their intentions lack moral ambiguity, rare cases of success legitimize law enforcement and other agencies, and they appeal to the public sense of responsibility in preventing crime. Yet the goal of saving infant lives may be unattainable. These qualities make the effectiveness of the laws questionable and suggest they may be counterproductive. This analysis determined that safe haven laws are socially constructed solutions to the socially constructed problem of child abandonment. Safe haven laws are appropriately classified as crime control theater. It is imperative that further research be conducted to examine the effectiveness and collateral effects of safe haven laws. Longitudinal studies and a nationwide database to better determine the effectiveness of safe haven laws are suggested. It is also crucial that agencies implementing SHLs closely monitor the reasons parents abandon their children, and adopt policies that re-focus the attention safe haven laws receive to address more frequent causes of harm to infants. Copyright © 2010 Elsevier Ltd. All rights reserved.

Performance Validation of Version 152.0 ANSER Control Laws for the F-18 HARV

NASA Technical Reports Server (NTRS)

Messina, Michael D.

1996-01-01

The Actuated Nose Strakes for Enhanced Rolling (ANSER) Control Laws were modified as a result of Phase 3 F/A-18 High Alpha Research Vehicle (HARV) flight testing. The control law modifications for the next software release were designated version 152.0. The Ada implementation was tested in the Hardware-In-the-Loop (HIL) simulation and results were compared to those obtained with the NASA Langley batch Fortran implementation of the control laws which are considered the 'truth model.' This report documents the performance validation test results between these implementations for ANSER control law version 152.0.

Steering Law Design for Redundant Single Gimbal Control Moment Gyro Systems. M.S. Thesis - Massachusetts Inst. of Technology.

NASA Technical Reports Server (NTRS)

Bedrossian, Nazareth Sarkis

1987-01-01

The correspondence between robotic manipulators and single gimbal Control Moment Gyro (CMG) systems was exploited to aid in the understanding and design of single gimbal CMG Steering laws. A test for null motion near a singular CMG configuration was derived which is able to distinguish between escapable and unescapable singular states. Detailed analysis of the Jacobian matrix null-space was performed and results were used to develop and test a variety of single gimbal CMG steering laws. Computer simulations showed that all existing singularity avoidance methods are unable to avoid Elliptic internal singularities. A new null motion algorithm using the Moore-Penrose pseudoinverse, however, was shown by simulation to avoid Elliptic type singularities under certain conditions. The SR-inverse, with appropriate null motion was proposed as a general approach to singularity avoidance, because of its ability to avoid singularities through limited introduction of torque error. Simulation results confirmed the superior performance of this method compared to the other available and proposed pseudoinverse-based Steering laws.

Control Laws for a Dual-Spin Stabilized Platform

NASA Technical Reports Server (NTRS)

Lim, K. B.; Moerder, D. D.

2008-01-01

This paper describes two attitude control laws suitable for atmospheric flight vehicles with a steady angular momentum bias in the vehicle yaw axis. This bias is assumed to be provided by an internal flywheel, and is introduced to enhance roll and pitch stiffness. The first control law is based on Lyapunov stability theory, and stability proofs are given. The second control law, which assumes that the angular momentum bias is large, is based on a classical PID control. It is shown that the large yaw-axis bias requires that the PI feedback component on the roll and pitch angle errors be cross-fed. Both control laws are applied to a vehicle simulation in the presence of disturbances for several values of yaw-axis angular momentum bias. It is seen that both control laws provide a significant improvement in attitude performance when the bias is sufficiently large, but the nonlinear control law is also able to provide improved performance for a small value of bias. This is important because the smaller bias corresponds to a smaller requirement for mass to be dedicated to the flywheel.

Flight evaluations of several hover control and display combinations for precise blind vertical landings

NASA Technical Reports Server (NTRS)

Schroeder, J. A.; Merrick, V. K.

1990-01-01

Several control and display concepts were evaluated on a variable-stability helicopter prior to future evaluations on a modified Harrier. The control and display concepts had been developed to enable precise hover maneuvers, station keeping, and vertical landings in simulated zero-visibility conditions and had been evaluated extensively in previous piloted simulations. Flight evaluations early in the program revealed several inadequacies in the display drive laws that were later corrected using an alternative design approach that integrated the control and display characteristics with the desired guidance law. While hooded, three pilots performed landing-pad captures followed by vertical landings with attitude-rate, attitude, and translation-velocity-command control systems. The latter control system incorporated a modified version of state-rate-feedback implicit-model following. Precise landing within 2 ft of the desired touchdown point were achieved.

Restricted Complexity Framework for Nonlinear Adaptive Control in Complex Systems

NASA Astrophysics Data System (ADS)

Williams, Rube B.

2004-02-01

Control law adaptation that includes implicit or explicit adaptive state estimation, can be a fundamental underpinning for the success of intelligent control in complex systems, particularly during subsystem failures, where vital system states and parameters can be impractical or impossible to measure directly. A practical algorithm is proposed for adaptive state filtering and control in nonlinear dynamic systems when the state equations are unknown or are too complex to model analytically. The state equations and inverse plant model are approximated by using neural networks. A framework for a neural network based nonlinear dynamic inversion control law is proposed, as an extrapolation of prior developed restricted complexity methodology used to formulate the adaptive state filter. Examples of adaptive filter performance are presented for an SSME simulation with high pressure turbine failure to support extrapolations to adaptive control problems.

Vibration suppression of planar truss structures utilizing uniform damping control

NASA Technical Reports Server (NTRS)

Andersen, G. C.; Silverberg, L. M.

1986-01-01

A variety of methods has been devised for vibrational control of a structure using both passive and active controls. Presented in this paper is a relatively new method for vibration suppression, uniform damping control. This method consists of implementing a control law which tends to dampen each vibrational mode of the structure at the same desirable exponential rate. The unique aspects of this method are that the control law is not explicitly dependent on the structural stiffness, the control forces are directly proportional to the distribution of the structural mass, and the control law is natural and decentralized. The control law was applied to a flexible planar truss structure and the various aspects of implementation of the control law examined are: actuator/sensor number, placement, and the impact of the actuator/sensor number and placement on the necessary control 'power' requirements such as peak power loads, total power requirements, etc. Also examined are the effects of using a limited number of active members in terms of the vibrational performance when compared with the 'ideal' distributed control law.

Development of an advanced pitch active control system for a wide body jet aircraft

NASA Technical Reports Server (NTRS)

Guinn, Wiley A.; Rising, Jerry J.; Davis, Walt J.

1984-01-01

An advanced PACS control law was developed for a commercial wide-body transport (Lockheed L-1011) by using modern control theory. Validity of the control law was demonstrated by piloted flight simulation tests on the NASA Langley visual motion simulator. The PACS design objective was to develop a PACS that would provide good flying qualities to negative 10 percent static stability margins that were equivalent to those of the baseline aircraft at a 15 percent static stability margin which is normal for the L-1011. Also, the PACS was to compensate for high-Mach/high-g instabilities that degrade flying qualities during upset recoveries and maneuvers. The piloted flight simulation tests showed that the PACS met the design objectives. The simulation demonstrated good flying qualities to negative 20 percent static stability margins for hold, cruise and high-speed flight conditions. Analysis and wind tunnel tests performed on other Lockheed programs indicate that the PACS could be used on an advanced transport configuration to provide a 4 percent fuel savings which results from reduced trim drag by flying at negative static stability margins.

Optimization of Closed Loop Eigenvalues: Maneuvering, Vibration Control, and Structure/Control Design Iteration for Flexible Spacecraft.

DTIC Science & Technology

1986-05-31

Nonlinear Feedback Control 8-16 for Spacecraft Attitude Maneuvers" 2. " Spacecraft Attitude Control Using 17-35... nonlinear state feedback control laws are developed for space- craft attitude control using the Euler parameters and conjugate angular momenta. Time... Nonlinear Feedback Control for Spacecraft Attitude Maneuvers," to appear in AIAA J. of Guidance, Control, and Dynamics, (AIAA Paper No. 83-2230-CP,

Local smoke-free policy development in Santa Fe, Argentina

PubMed Central

Glantz, Stanton A

2010-01-01

Objective To describe the process of approval and implementation of a comprehensive smoke-free law in the province of Santa Fe, Argentina, between 2005 and 2009. Methods Review of the Santa Fe smoke-free legislation, articles published in local newspapers and documentation on two lawsuits filed against the law, and interviews with key individuals in Santa Fe. Results Efforts to implement smoke-free policies in Santa Fe began during the 1990s without success, and resumed in 2005 when the provincial Legislature approved the first 100% smoke-free subnational law in Argentina. There was no strong opposition during the discussions within the legislature. As in other parts of the world, pro-tobacco industry interests attempted to block the implementation of the law using well known strategies. These efforts included a controversy media campaign set up, the creation of a hospitality industry association and a virtual smokers' rights group, the introduction of a counterproposal seeking modification of the law, the challenge of the law in the Supreme Court, and the proposal of a weak national bill that would ‘conflict’ with the subnational law. Tobacco control advocates sought media attention as a strategy to protect the law. Conclusions Santa Fe is the first subnational jurisdiction in Latin America to have enacted a comprehensive smoke-free policy following the recommendations of the World Health Organization (WHO) Framework Convention on Tobacco Control. After 3 years of implementation, pro-tobacco industry forces failed to undermine the law. Other subnational jurisdictions in Argentina, as well as in Mexico and Brazil are following the Santa Fe example. PMID:19955534

Local smoke-free policy development in Santa Fe, Argentina.

PubMed

Sebrié, Ernesto M; Glantz, Stanton A

2010-04-01

To describe the process of approval and implementation of a comprehensive smoke-free law in the province of Santa Fe, Argentina, between 2005 and 2009. Review of the Santa Fe smoke-free legislation, articles published in local newspapers and documentation on two lawsuits filed against the law, and interviews with key individuals in Santa Fe. Efforts to implement smoke-free policies in Santa Fe began during the 1990s without success, and resumed in 2005 when the provincial Legislature approved the first 100% smoke-free subnational law in Argentina. There was no strong opposition during the discussions within the legislature. As in other parts of the world, pro-tobacco industry interests attempted to block the implementation of the law using well known strategies. These efforts included a controversy media campaign set up, the creation of a hospitality industry association and a virtual smokers' rights group, the introduction of a counterproposal seeking modification of the law, the challenge of the law in the Supreme Court, and the proposal of a weak national bill that would 'conflict' with the subnational law. Tobacco control advocates sought media attention as a strategy to protect the law. Santa Fe is the first subnational jurisdiction in Latin America to have enacted a comprehensive smoke-free policy following the recommendations of the World Health Organization (WHO) Framework Convention on Tobacco Control. After 3 years of implementation, pro-tobacco industry forces failed to undermine the law. Other subnational jurisdictions in Argentina, as well as in Mexico and Brazil are following the Santa Fe example.

Distributed reconfigurable control strategies for switching topology networked multi-agent systems.

PubMed

Gallehdari, Z; Meskin, N; Khorasani, K

2017-11-01

In this paper, distributed control reconfiguration strategies for directed switching topology networked multi-agent systems are developed and investigated. The proposed control strategies are invoked when the agents are subject to actuator faults and while the available fault detection and isolation (FDI) modules provide inaccurate and unreliable information on the estimation of faults severities. Our proposed strategies will ensure that the agents reach a consensus while an upper bound on the team performance index is ensured and satisfied. Three types of actuator faults are considered, namely: the loss of effectiveness fault, the outage fault, and the stuck fault. By utilizing quadratic and convex hull (composite) Lyapunov functions, two cooperative and distributed recovery strategies are designed and provided to select the gains of the proposed control laws such that the team objectives are guaranteed. Our proposed reconfigurable control laws are applied to a team of autonomous underwater vehicles (AUVs) under directed switching topologies and subject to simultaneous actuator faults. Simulation results demonstrate the effectiveness of our proposed distributed reconfiguration control laws in compensating for the effects of sudden actuator faults and subject to fault diagnosis module uncertainties and unreliabilities. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

Reconfigurable Software for Controlling Formation Flying

NASA Technical Reports Server (NTRS)

Mueller, Joseph B.

2006-01-01

Software for a system to control the trajectories of multiple spacecraft flying in formation is being developed to reflect underlying concepts of (1) a decentralized approach to guidance and control and (2) reconfigurability of the control system, including reconfigurability of the software and of control laws. The software is organized as a modular network of software tasks. The computational load for both determining relative trajectories and planning maneuvers is shared equally among all spacecraft in a cluster. The flexibility and robustness of the software are apparent in the fact that tasks can be added, removed, or replaced during flight. In a computational simulation of a representative formation-flying scenario, it was demonstrated that the following are among the services performed by the software: Uploading of commands from a ground station and distribution of the commands among the spacecraft, Autonomous initiation and reconfiguration of formations, Autonomous formation of teams through negotiations among the spacecraft, Working out details of high-level commands (e.g., shapes and sizes of geometrically complex formations), Implementation of a distributed guidance law providing autonomous optimization and assignment of target states, and Implementation of a decentralized, fuel-optimal, impulsive control law for planning maneuvers.

Digital autopilots: Design considerations and simulator evaluations

NASA Technical Reports Server (NTRS)

Osder, S.; Neuman, F.; Foster, J.

1971-01-01

The development of a digital autopilot program for a transport aircraft and the evaluation of that system's performance on a transport aircraft simulator is discussed. The digital autopilot includes three axis attitude stabilization, automatic throttle control and flight path guidance functions with emphasis on the mode progression from descent into the terminal area through automatic landing. The study effort involved a sequence of tasks starting with the definition of detailed system block diagrams of control laws followed by a flow charting and programming phase and concluding with performance verification using the transport aircraft simulation. The autopilot control laws were programmed in FORTRAN 4 in order to isolate the design process from requirements peculiar to an individual computer.

Virginia Erosion and Sediment Control Handbook. Standards, Criteria and Guidelines.

ERIC Educational Resources Information Center

Virginia State Soil and Water Conservation Commission, Richmond, VA.

Guidelines and technical standards for development of local erosion and sediment control programs and conservation standards to meet the goals established by the Virginia Erosion and Sediment Control law are presented in this handbook. Part I defines natural and manmade erosion, sedimentation, and the hazards of uncontrolled wear and damage to the…

Dynamic characterization and microprocessor control of the NASA/UVA proof mass actuator

NASA Technical Reports Server (NTRS)

Zimmerman, D. C.; Inman, D. J.; Horner, G. C.

1984-01-01

The self-contained electromagnetic-reaction-type force-actuator system developed by NASA/UVA for the verification of spacecraft-structure vibration-control laws is characterized and demonstrated. The device is controlled by a dedicated microprocessor and has dynamic characteristics determined by Fourier analysis. Test data on a cantilevered beam are shown.

Full Flight Envelope Inner Loop Control Law Development for the Unmanned K-MAX

DTIC Science & Technology

2011-05-03

LaMontagne , T., "System Identification and Control System Design for the BURRO Autonomous UAV," Proceedings of the American Helicopter Society 56th...Annual Forum, Virginia Beach, Virginia, May 2000. 2. Frost, C., Tischler, M., Bielefield, M., & LaMontagne , T., "Design and Test of Flight Control

Research flight-control system development for the F-18 high alpha research vehicle

NASA Technical Reports Server (NTRS)

Pahle, Joseph W.; Powers, Bruce; Regenie, Victoria; Chacon, Vince; Degroote, Steve; Murnyak, Steven

1991-01-01

The F-18 high alpha research vehicle was recently modified by adding a thrust vectoring control system. A key element in the modification was the development of a research flight control system integrated with the basic F-18 flight control system. Discussed here are design requirements, system development, and research utility of the resulting configuration as an embedded system for flight research in the high angle of attack regime. Particular emphasis is given to control system modifications and control law features required for high angle of attack flight. Simulation results are used to illustrate some of the thrust vectoring control system capabilities and predicted maneuvering improvements.

The multiple-function multi-input/multi-output digital controller system for the AFW wind-tunnel model

NASA Technical Reports Server (NTRS)

Hoadley, Sherwood T.; Mcgraw, Sandra M.

1992-01-01

A real time multiple-function digital controller system was developed for the Active Flexible Wing (AFW) Program. The digital controller system (DCS) allowed simultaneous execution of two control laws: flutter suppression and either roll trim or a rolling maneuver load control. The DCS operated within, but independently of, a slower host operating system environment, at regulated speeds up to 200 Hz. It also coordinated the acquisition, storage, and transfer of data for near real time controller performance evaluation and both open- and closed-loop plant estimation. It synchronized the operation of four different processing units, allowing flexibility in the number, form, functionality, and order of control laws, and variability in the selection of the sensors and actuators employed. Most importantly, the DCS allowed for the successful demonstration of active flutter suppression to conditions approximately 26 percent (in dynamic pressure) above the open-loop boundary in cases when the model was fixed in roll and up to 23 percent when it was free to roll. Aggressive roll maneuvers with load control were achieved above the flutter boundary. The purpose here is to present the development, validation, and wind tunnel testing of this multiple-function digital controller system.

High-Alpha Research Vehicle Lateral-Directional Control Law Description, Analyses, and Simulation Results

NASA Technical Reports Server (NTRS)

Davidson, John B.; Murphy, Patrick C.; Lallman, Frederick J.; Hoffler, Keith D.; Bacon, Barton J.

1998-01-01

This report contains a description of a lateral-directional control law designed for the NASA High-Alpha Research Vehicle (HARV). The HARV is a F/A-18 aircraft modified to include a research flight computer, spin chute, and thrust-vectoring in the pitch and yaw axes. Two separate design tools, CRAFT and Pseudo Controls, were integrated to synthesize the lateral-directional control law. This report contains a description of the lateral-directional control law, analyses, and nonlinear simulation (batch and piloted) results. Linear analysis results include closed-loop eigenvalues, stability margins, robustness to changes in various plant parameters, and servo-elastic frequency responses. Step time responses from nonlinear batch simulation are presented and compared to design guidelines. Piloted simulation task scenarios, task guidelines, and pilot subjective ratings for the various maneuvers are discussed. Linear analysis shows that the control law meets the stability margin guidelines and is robust to stability and control parameter changes. Nonlinear batch simulation analysis shows the control law exhibits good performance and meets most of the design guidelines over the entire range of angle-of-attack. This control law (designated NASA-1A) was flight tested during the Summer of 1994 at NASA Dryden Flight Research Center.

Control of nonlinear systems using terminal sliding modes

NASA Technical Reports Server (NTRS)

Venkataraman, S. T.; Gulati, S.

1992-01-01

The development of an approach to control synthesis for robust robot operations in unstructured environments is discussed. To enhance control performance with full model information, the authors introduce the notion of terminal convergence and develop control laws based on a class of sliding modes, denoted as terminal sliders. They demonstrate that terminal sliders provide robustness to parametric uncertainty without having to resort to high-frequency control switching, as in the case of conventional sliders. It is shown that the proposed method leads to greater guaranteed precision in all control cases discussed.

Land use politics and law in the 1970's

NASA Technical Reports Server (NTRS)

Lamb, C. M.

1975-01-01

Political facets of the general land use challenge faced in the United States, and the legal authority for governmental action by state and federal officials under given conditions are discussed. Some current and future implications of these political and legal developments are presented. An overview of local versus state versus federal powers is presented along with practices for solving the nation's land use challenge. An analysis is provided of land use law and politics in five states playing active roles in land control. Land use politics and law at the federal level is addressed, with emphasis on three key legislative measures.

Youth Attitudes towards Tobacco Control Laws: The Influence of Smoking Status and Grade in School

ERIC Educational Resources Information Center

Williams, Terrinieka T.; Jason, Leonard A.; Pokorny, Steven B.

2008-01-01

This study examined adolescent attitudes towards tobacco control laws. An exploratory factor analysis, using surveys from over 9,000 students, identified the following three factors: (1) youth attitudes towards the efficacy of tobacco control laws, (2) youth attitudes towards tobacco possession laws and (3) youth attitudes towards tobacco sales…

Tobacco control laws in Pakistan and their implementation: A pilot study in Karachi.

PubMed

Khan, Javaid Ahmed; Amir Humza Sohail, Abdul Malik; Arif Maan, Muhammad Arslan

2016-07-01

In order to limit the high prevalence of tobacco use in Pakistan various tobacco control laws have been implemented. The objective of this study is to serve as a pilot study to assess the implementation of these laws in the largest city of Pakistan, Karachi. A cross-sectional study was conducted in Karachi. The implementation of tobacco control laws in 'smoke-free' places, the adherence of tobacco companies to these laws, the regulation of cigarette sale, and the awareness and views of the general public regarding tobacco control laws were assessed via direct observation by visits and through self-administered questionnaires. The implementation of tobacco control laws in 'smoke-free' public places was found to be poor. Out of 37, only 23(62%) brands displayed pictorial warnings on their packs. 3(8%) of the brands were available in two different kinds of packs, both with and without pictorial warnings. Cigarette sale to minors was taking place at 80(85%) of the visited cigarette outlets. 50(53%) of the outlets displayed cigarette advertisements in the form of posters. 46(40%) of the persons questioned had awareness regarding the existence of ban on smoking in public places and 126(90%) of these were in favour of it. The implementation of tobacco control law in Pakistan is poor. Non adherence to the law in public places was alarmingly high. Also, the study demonstrates the poor compliance to the tobacco control laws by tobacco companies. The sale of cigarettes is almost unregulated.

Adaptive nonsingular fast terminal sliding-mode control for the tracking problem of uncertain dynamical systems.

PubMed

Boukattaya, Mohamed; Mezghani, Neila; Damak, Tarak

2018-06-01

In this paper, robust and adaptive nonsingular fast terminal sliding-mode (NFTSM) control schemes for the trajectory tracking problem are proposed with known or unknown upper bound of the system uncertainty and external disturbances. The developed controllers take the advantage of the NFTSM theory to ensure fast convergence rate, singularity avoidance, and robustness against uncertainties and external disturbances. First, a robust NFTSM controller is proposed which guarantees that sliding surface and equilibrium point can be reached in a short finite-time from any initial state. Then, in order to cope with the unknown upper bound of the system uncertainty which may be occurring in practical applications, a new adaptive NFTSM algorithm is developed. One feature of the proposed control law is their adaptation techniques where the prior knowledge of parameters uncertainty and disturbances is not needed. However, the adaptive tuning law can estimate the upper bound of these uncertainties using only position and velocity measurements. Moreover, the proposed controller eliminates the chattering effect without losing the robustness property and the precision. Stability analysis is performed using the Lyapunov stability theory, and simulation studies are conducted to verify the effectiveness of the developed control schemes. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Deadbeat Predictive Controllers

NASA Technical Reports Server (NTRS)

Juang, Jer-Nan; Phan, Minh

1997-01-01

Several new computational algorithms are presented to compute the deadbeat predictive control law. The first algorithm makes use of a multi-step-ahead output prediction to compute the control law without explicitly calculating the controllability matrix. The system identification must be performed first and then the predictive control law is designed. The second algorithm uses the input and output data directly to compute the feedback law. It combines the system identification and the predictive control law into one formulation. The third algorithm uses an observable-canonical form realization to design the predictive controller. The relationship between all three algorithms is established through the use of the state-space representation. All algorithms are applicable to multi-input, multi-output systems with disturbance inputs. In addition to the feedback terms, feed forward terms may also be added for disturbance inputs if they are measurable. Although the feedforward terms do not influence the stability of the closed-loop feedback law, they enhance the performance of the controlled system.

Model reduction methods for control design

NASA Technical Reports Server (NTRS)

Dunipace, K. R.

1988-01-01

Several different model reduction methods are developed and detailed implementation information is provided for those methods. Command files to implement the model reduction methods in a proprietary control law analysis and design package are presented. A comparison and discussion of the various reduction techniques is included.

System design of the annular suspension and pointing system /ASPS/

NASA Technical Reports Server (NTRS)

Cunningham, D. C.; Gismondi, T. P.; Wilson, G. W.

1978-01-01

This paper presents the control system design for the Annular Suspension and Pointing System. Actuator sizing and configuration of the system are explained, and the control laws developed for linearizing and compensating the magnetic bearings, roll induction motor and gimbal torquers are given. Decoupling, feedforward and error compensation for the vernier and gimbal controllers is developed. The algorithm for computing the strapdown attitude reference is derived, and the allowable sampling rates, time delays and quantization of control signals are specified.

30 CFR 905.773 - Requirements for permits and permit processing.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., 42 U.S.C. 7401 et seq California Air Pollution Control Laws, Cal. Health & Safety Code section 39000... (11) Noise Control Act, 42 U.S.C. 4903 California Noise Control Act of 1973, Cal. Health & Safety Code... Pollution Control Laws, Cal. Health & Safety Code section 39000 et seq.; the Hazardous Waste Control Law...

[Reform of Japan's NTP and its technical perspectives].

PubMed

Mori, Toru

2004-10-01

The 1951 Tuberculosis Control Law of Japan is now faced with tremendous changes that have occurred during the last 50 years in tuberculosis epidemiology and in the environment in tuberculosis control implementation. The law is also challenged with the shift of the paradigm for the National Tuberculosis (TB) Programme. In order to respond properly to these changes, the Tuberculosis Panel of the Health Science Council of the Ministry of Health, Labor and Welfare submitted its report for the amendment of the law in March 2002. Based on this report, a new Tuberculosis Control Law was passed in Parliament last June, and related decrees of the Cabinet and the Ministry are now being revised in preparation for it's enactment in April 2005. In this special lecture, the main points and framework of the revisions were discussed with the perspective of the development of new technical innovations relevant to each area of the revised TB control legislation. 1. Case detection. There will be a shift from the current "indiscriminate" screening scheme to a selective one regarding periodic mass health examination. Only subjects aged 65 or older will be eligible for the screening, supplemented with selected occupational groups who are considered to be at a higher risk of TB, or may be a danger to others if they develop TB, such as health-care providers and school teachers. In addition, local autonomies are responsible for offering screening to the socio-economic high-risk populations, such as homeless people, slum residents, day laborers, and/or workers in small businesses. This means that the efforts of the autonomies are critical for the new system to be effective. The extra-ordinary examination will be limited to only the patient's contacts, and will be mandatory for those contacts so they cannot refuse to be examined by the Health Center. The public services used in the contact investigations will be greatly facilitated by such new technologies as DNA fingerprinting of TB bacilli and a new diagnostic of TB infection using whole-blood interferon-gamma determination (QuantiFERON). The quality of clinical diagnosis and monitoring of treatment should also be improved by introducing an external quality assurance system of commercial laboratory services. 2. Chemoprophylaxis. Although not explicitly defined in the new legislation, the expansion and improvement of chemoprophylaxis to cover anyone with any risk of clinical development of TB would have a tremendous effect in Japan, especially since 90% of patients who developed TB were infected tens of years ago. These technical innovations in diagnosis of TB infection will be very helpful. Development of new drug regimens for the preventive treatment is also badly needed. 3. Immunization. Prior to the amendment of the Law, the BCG vaccination of students entering primary and junior high schools has been already abandoned. In order to encourage the early primary vaccination for infants, the new Law will adopt the direct vaccination scheme in which babies will be given the BCG vaccine without tuberculin testing. This program will be implemented safely, only if it is given to young babies, e.g., less than one year old, as defined by the decree. It is essential to maintain the high level of vaccination coverage under the new program. The autonomy may encounter difficulty mobilizing client babies shortly after their birth (only one year, as compared with the current four years). To avoid the possible, though very rare, adverse health effects due to the vaccination of infected babies, careful questioning should be conducted regarding the risk of exposure to infection prior to vaccination. A ready course of treatment and examinations for abnormal reactions after vaccination (Koch's phenomenon) is also warranted. 4. Treatment and patient care: The revised Law clearly states the governmental responsibility for treating TB patients in close cooperation with a doctor. This is an important legal basis for the expansion of the DOTS Japan version. While the development of new anti-tuberculosis drugs will be realized in the near future, Japan still has to overcome the issue of improper practice of treatment, as well as the government's slow process for approving new drugs to be used for multi-drug resistant TB and non-tuberculous mycobacterioses. 5. Prefectural TB Control Plan: In order to resolve the problems specific to the respective prefectures in terms of epidemiological parameters or available resources, the new Law requests every prefecture to develop its own TB control plan. In order for the new TB Control Law to be effective, strong government commitment supported by technological innovation is mandatory. It is for that reason that the Japanese Society of Tuberculosis should aggressively join the global movement to stop TB along with the general public of Japan.

Analytical and Experimental Evaluation of Digital Control Systems for the Semi-Span Super-Sonic Transport (S4T) Wind Tunnel Model

NASA Technical Reports Server (NTRS)

Wieseman, Carol D.; Christhilf, David; Perry, Boyd, III

2012-01-01

An important objective of the Semi-Span Super-Sonic Transport (S4T) wind tunnel model program was the demonstration of Flutter Suppression (FS), Gust Load Alleviation (GLA), and Ride Quality Enhancement (RQE). It was critical to evaluate the stability and robustness of these control laws analytically before testing them and experimentally while testing them to ensure safety of the model and the wind tunnel. MATLAB based software was applied to evaluate the performance of closed-loop systems in terms of stability and robustness. Existing software tools were extended to use analytical representations of the S4T and the control laws to analyze and evaluate the control laws prior to testing. Lessons were learned about the complex windtunnel model and experimental testing. The open-loop flutter boundary was determined from the closed-loop systems. A MATLAB/Simulink Simulation developed under the program is available for future work to improve the CPE process. This paper is one of a series of that comprise a special session, which summarizes the S4T wind-tunnel program.

The role of public policies in reducing smoking and deaths caused by smoking in Vietnam: results from the Vietnam tobacco policy simulation model.

PubMed

Levy, David T; Bales, Sarah; Lam, Nguyen T; Nikolayev, Leonid

2006-04-01

A simulation model is developed for Vietnam to project smoking prevalence and associated premature mortality. The model examines independently and as a package the effects of five types of tobacco control policies: tax increases, clean air laws, mass media campaigns, advertising bans, and youth access policies. Predictions suggest that the largest reductions in smoking rates will result from implementing a comprehensive tobacco control policy package. Significant inroads may be achieved through tax increases. A media campaign along with programs to publicize and enforce clean air laws, advertising bans and youth access laws would further reduce smoking rates. Tobacco control policies have the potential to make large dents in smoking rates, which in turn could lead to many lives saved. In the absence of these measures, deaths from smoking will increase. The model also helps to identify information gaps pertinent both to modeling and policy-making.

Energy extraction from atmospheric turbulence to improve flight vehicle performance

NASA Astrophysics Data System (ADS)

Patel, Chinmay Karsandas

Small 'bird-sized' Unmanned Aerial Vehicles (UAVs) have now become practical due to technological advances in embedded electronics, miniature sensors and actuators, and propulsion systems. Birds are known to take advantage of wind currents to conserve energy and fly long distances without flapping their wings. This dissertation explores the possibility of improving the performance of small UAVs by extracting the energy available in atmospheric turbulence. An aircraft can gain energy from vertical gusts by increasing its lift in regions of updraft and reducing its lift in downdrafts - a concept that has been known for decades. Starting with a simple model of a glider flying through a sinusoidal gust, a parametric optimization approach is used to compute the minimum gust amplitude and optimal control input required for the glider to sustain flight without losing energy. For small UAVs using optimal control inputs, sinusoidal gusts with amplitude of 10--15% of the cruise speed are sufficient to keep the aircraft aloft. The method is then modified and extended to include random gusts that are representative of natural turbulence. A procedure to design optimal control laws for energy extraction from realistic gust profiles is developed using a Genetic Algorithm (GA). A feedback control law is designed to perform well over a variety of random gusts, and not be tailored for one particular gust. A small UAV flying in vertical turbulence is shown to obtain average energy savings of 35--40% with the use of a simple control law. The design procedure is also extended to determine optimal control laws for sinusoidal as well as turbulent lateral gusts. The theoretical work is complemented by experimental validation using a small autonomous UAV. The development of a lightweight autopilot and UAV platform is presented. Flight test results show that active control of the lift of an autonomous glider resulted in approximately 46% average energy savings compared to glides with fixed control surfaces. Statistical analysis of test samples shows that 19% of the active control test runs resulted in no energy loss, thus demonstrating the potential of the 'gust soaring' concept to dramatically improve the performance of small UAVs.

ERPs and Psychopathology. I. Behavioral process issues.

PubMed

Roth, W T; Tecce, J J; Pfefferbaum, A; Rosenbloom, M; Callaway, E

1984-01-01

The clinical study of ERPs has an inherent defect--a self-selection of clinical populations that hampers equating of clinically defined groups on factors extraneous to the independent variables. Such ex post facto studies increase the likelihood of confounding variables in the interpretation of findings. Hence, the development of lawful relationships between clinical variables and ERPs is impeded and the fulfillment of description, explanation, prediction, and control in brain science is thwarted. Proper methodologies and theory development can increase the likelihood of establishing these lawful relationships. One methodology of potential value in the clinical application of ERPs, particularly in studies of aging, is that of divided attention. Two promising theoretical developments in the understanding of brain functioning and aging are the distraction-arousal hypothesis and the controlled-automatic attention model. The evaluation of ERPs in the study of brain-behavior relations in clinical populations might be facilitated by the differentiation of concurrent, predictive, content, and construct validities.

Development of a Design Methodology for Reconfigurable Flight Control Systems

NASA Technical Reports Server (NTRS)

Hess, Ronald A.; McLean, C.

2000-01-01

A methodology is presented for the design of flight control systems that exhibit stability and performance-robustness in the presence of actuator failures. The design is based upon two elements. The first element consists of a control law that will ensure at least stability in the presence of a class of actuator failures. This law is created by inner-loop, reduced-order, linear dynamic inversion, and outer-loop compensation based upon Quantitative Feedback Theory. The second element consists of adaptive compensators obtained from simple and approximate time-domain identification of the dynamics of the 'effective vehicle' with failed actuator(s). An example involving the lateral-directional control of a fighter aircraft is employed both to introduce the proposed methodology and to demonstrate its effectiveness and limitations.

Accelerated development and flight evaluation of active controls concepts for subsonic transport aircraft. Volume 2: AFT C.G. simulation and analysis

NASA Technical Reports Server (NTRS)

Urie, D. M.

1979-01-01

Relaxed static stability and stability augmentation with active controls were investigated for subsonic transport aircraft. Analytical and simulator evaluations were done using a contemporary wide body transport as a baseline. Criteria for augmentation system performance and unaugmented flying qualities were evaluated. Augmentation control laws were defined based on selected frequency response and time history criteria. Flying qualities evaluations were conducted by pilots using a moving base simulator with a transport cab. Static margin and air turbulence intensity were varied in test with and without augmentation. Suitability of a simple pitch control law was verified at neutral static margin in cruise and landing flight tasks. Neutral stability was found to be marginally acceptable in heavy turbulence in both cruise and landing conditions.

Design and pilot evaluation of the RAH-66 Comanche selectable control modes

NASA Technical Reports Server (NTRS)

Gold, Phillip J.; Dryfoos, James B.

1993-01-01

The RAH-66 Comanche helicopter has been designed to possess superior handling qualities over a wide range of flight conditions. The control laws have been tailored to satisfy the requirements of ADS-33C and the Weapon System Specification (WSS). This paper addresses the design of the Comanche Selectable Mode control laws (Velocity Stabilization/Hover Hold and Altitude Hold), which provide the additional stabilization and control augmentation needed when flying in a Degraded Visual Environment (DVE). An overview of the RAH-66 control laws is presented, including a detailed description of the Selectable Modes design. The primary focus of this paper is the results of piloted evaluation of these control laws in the Boeing motionbase simulator. These tests substantiate the detailed design of the Comanche Selectable Mode control laws. All tested DVE tasks (ADS-33C, sections 4.4 and 4.5) were rated Level 1. Other evaluation tasks confirmed the mission suitability of the control system. These control laws are ready for formal ADS-33C compliance testing in the Sikorsky Full Mission Simulator (FMS).

Drag reduction of a car model by linear genetic programming control

NASA Astrophysics Data System (ADS)

Li, Ruiying; Noack, Bernd R.; Cordier, Laurent; Borée, Jacques; Harambat, Fabien

2017-08-01

We investigate open- and closed-loop active control for aerodynamic drag reduction of a car model. Turbulent flow around a blunt-edged Ahmed body is examined at ReH≈ 3× 105 based on body height. The actuation is performed with pulsed jets at all trailing edges (multiple inputs) combined with a Coanda deflection surface. The flow is monitored with 16 pressure sensors distributed at the rear side (multiple outputs). We apply a recently developed model-free control strategy building on genetic programming in Dracopoulos and Kent (Neural Comput Appl 6:214-228, 1997) and Gautier et al. (J Fluid Mech 770:424-441, 2015). The optimized control laws comprise periodic forcing, multi-frequency forcing and sensor-based feedback including also time-history information feedback and combinations thereof. Key enabler is linear genetic programming (LGP) as powerful regression technique for optimizing the multiple-input multiple-output control laws. The proposed LGP control can select the best open- or closed-loop control in an unsupervised manner. Approximately 33% base pressure recovery associated with 22% drag reduction is achieved in all considered classes of control laws. Intriguingly, the feedback actuation emulates periodic high-frequency forcing. In addition, the control identified automatically the only sensor which listens to high-frequency flow components with good signal to noise ratio. Our control strategy is, in principle, applicable to all multiple actuators and sensors experiments.

Open Source Software and the Intellectual Commons.

ERIC Educational Resources Information Center

Dorman, David

2002-01-01

Discusses the Open Source Software method of software development and its relationship to control over information content. Topics include digital library resources; reference services; preservation; the legal and economic status of information; technical standards; access to digital data; control of information use; and copyright and patent laws.…

Spacecraft momentum management procedures. [large space telescope

NASA Technical Reports Server (NTRS)

Chen, L. C.; Davenport, P. B.; Sturch, C. R.

1980-01-01

Techniques appropriate for implementation onboard the space telescope and other spacecraft to manage the accumulation of momentum in reaction wheel control systems using magnetic torquing coils are described. Generalized analytical equations are derived for momentum control laws that command the magnetic torquers. These control laws naturally fall into two main categories according to the methods used for updating the magnetic dipole command: closed loop, in which the update is based on current measurements to achieve a desired torque instantaneously, and open-loop, in which the update is based on predicted information to achieve a desired momentum at the end of a period of time. Physical interpretations of control laws in general and of the Space Telescope cross product and minimum energy control laws in particular are presented, and their merits and drawbacks are discussed. A technique for retaining the advantages of both the open-loop and the closed-loop control laws is introduced. Simulation results are presented to compare the performance of these control laws in the Space Telescope environment.

Robust, nonlinear, high angle-of-attack control design for a supermaneuverable vehicle

NASA Technical Reports Server (NTRS)

Adams, Richard J.

1993-01-01

High angle-of-attack flight control laws are developed for a supermaneuverable fighter aircraft. The methods of dynamic inversion and structured singular value synthesis are combined into an approach which addresses both the nonlinearity and robustness problems of flight at extreme operating conditions. The primary purpose of the dynamic inversion control elements is to linearize the vehicle response across the flight envelope. Structured singular value synthesis is used to design a dynamic controller which provides robust tracking to pilot commands. The resulting control system achieves desired flying qualities and guarantees a large margin of robustness to uncertainties for high angle-of-attack flight conditions. The results of linear simulation and structured singular value stability analysis are presented to demonstrate satisfaction of the design criteria. High fidelity nonlinear simulation results show that the combined dynamics inversion/structured singular value synthesis control law achieves a high level of performance in a realistic environment.

Neural-Based Compensation of Nonlinearities in an Airplane Longitudinal Model with Dynamic-Inversion Control

PubMed Central

Li, YuHui; Jin, FeiTeng

2017-01-01

The inversion design approach is a very useful tool for the complex multiple-input-multiple-output nonlinear systems to implement the decoupling control goal, such as the airplane model and spacecraft model. In this work, the flight control law is proposed using the neural-based inversion design method associated with the nonlinear compensation for a general longitudinal model of the airplane. First, the nonlinear mathematic model is converted to the equivalent linear model based on the feedback linearization theory. Then, the flight control law integrated with this inversion model is developed to stabilize the nonlinear system and relieve the coupling effect. Afterwards, the inversion control combined with the neural network and nonlinear portion is presented to improve the transient performance and attenuate the uncertain effects on both external disturbances and model errors. Finally, the simulation results demonstrate the effectiveness of this controller. PMID:29410680

Environmental Law

DTIC Science & Technology

2002-06-01

Interior’s Bureau of Land Management (BLM). Flue - Gas Desulfurization (FGD). Post-combustion sulfur dioxide control technology in which a scrubber...4. Individual Control Strategies for Toxic Pollutants. a. The CWA requires states to identify “impaired” water bodies within their...water quality standards. Thereafter, states must develop “individual control strategies ” (ICSs) to regulate such pollutants and achieve water quality

On the stabilization of decentralized control systems.

NASA Technical Reports Server (NTRS)

Wang, S.-H.; Davison, E. J.

1973-01-01

This paper considers the problem of stabilizing a linear time-variant multivariable system by using several local feedback control laws. Each local feedback control law depends only on partial system outputs. A necessary and sufficient condition for the existence of local control laws with dynamic compensation to stabilize a given system is derived. This condition is stated in terms of a new notion, called fixed modes, which is a natural generalization of the well-known concept of uncontrollable modes and unobservable modes that occur in centralized control system problems. A procedure that constructs a set of stabilizing feedback control laws is given.

Backstepping Design of Adaptive Neural Fault-Tolerant Control for MIMO Nonlinear Systems.

PubMed

Gao, Hui; Song, Yongduan; Wen, Changyun

In this paper, an adaptive controller is developed for a class of multi-input and multioutput nonlinear systems with neural networks (NNs) used as a modeling tool. It is shown that all the signals in the closed-loop system with the proposed adaptive neural controller are globally uniformly bounded for any external input in . In our control design, the upper bound of the NN modeling error and the gains of external disturbance are characterized by unknown upper bounds, which is more rational to establish the stability in the adaptive NN control. Filter-based modification terms are used in the update laws of unknown parameters to improve the transient performance. Finally, fault-tolerant control is developed to accommodate actuator failure. An illustrative example applying the adaptive controller to control a rigid robot arm shows the validation of the proposed controller.In this paper, an adaptive controller is developed for a class of multi-input and multioutput nonlinear systems with neural networks (NNs) used as a modeling tool. It is shown that all the signals in the closed-loop system with the proposed adaptive neural controller are globally uniformly bounded for any external input in . In our control design, the upper bound of the NN modeling error and the gains of external disturbance are characterized by unknown upper bounds, which is more rational to establish the stability in the adaptive NN control. Filter-based modification terms are used in the update laws of unknown parameters to improve the transient performance. Finally, fault-tolerant control is developed to accommodate actuator failure. An illustrative example applying the adaptive controller to control a rigid robot arm shows the validation of the proposed controller.

Exponentially Stabilizing Robot Control Laws

NASA Technical Reports Server (NTRS)

Wen, John T.; Bayard, David S.

1990-01-01

New class of exponentially stabilizing laws for joint-level control of robotic manipulators introduced. In case of set-point control, approach offers simplicity of proportion/derivative control architecture. In case of tracking control, approach provides several important alternatives to completed-torque method, as far as computational requirements and convergence. New control laws modified in simple fashion to obtain asymptotically stable adaptive control, when robot model and/or payload mass properties unknown.

Predictive control and estimation algorithms for the NASA/JPL 70-meter antennas

NASA Technical Reports Server (NTRS)

Gawronski, W.

1991-01-01

A modified output prediction procedure and a new controller design is presented based on the predictive control law. Also, a new predictive estimator is developed to complement the controller and to enhance system performance. The predictive controller is designed and applied to the tracking control of the Deep Space Network 70 m antennas. Simulation results show significant improvement in tracking performance over the linear quadratic controller and estimator presently in use.

A stochastic regulator for integrated communication and control systems. I - Formulation of control law. II - Numerical analysis and simulation

NASA Technical Reports Server (NTRS)

Liou, Luen-Woei; Ray, Asok

1991-01-01

A state feedback control law for integrated communication and control systems (ICCS) is formulated by using the dynamic programming and optimality principle on a finite-time horizon. The control law is derived on the basis of a stochastic model of the plant which is augmented in state space to allow for the effects of randomly varying delays in the feedback loop. A numerical procedure for synthesizing the control parameters is then presented, and the performance of the control law is evaluated by simulating the flight dynamics model of an advanced aircraft. Finally, recommendations for future work are made.

Bioethics and law: a developmental perspective.

PubMed

van der Burg, Wibren

1997-04-01

In most Western countries, health law [and] bioethics are strongly intertwined. This strong connection is the result of some specific factors that, in the early years of these disciplines, facilitated a rapid development of both. In this paper, I analyze these factors and construe a development theory existing of three phases, or ideal-typical models. In the moralistic-paternalistic model, there is almost no health law of explicit medical ethics, and the little law there is is usually based on traditional morality, combined with paternalist motives. The objections to this model are that its paternalism and moralism are unacceptable, that it is too static and knows no external control mechanisms. In the liberal model, which is now dominant in most Western countries, law and ethics closely cooperate and converge, both disciplines use the same framework for analysis: they are product-oriented rather than practice-oriented; they use the same conceptual categories, they focus on minimally decent rather than the ideal, and they are committed to the same substantive normative theory in which patient autonomy and patient rights are central. However, each of these four characteristics also results in a certain one-sidedness. In some countries, a third model is emerging. In this postliberal model, health law is more modest and acknowledges its inherent and normative limits, whereas ethics takes a richer and most ambitious self image. As a result health law and ethics will partly diverge again.

Nonlinear control of magnetic bearings

NASA Technical Reports Server (NTRS)

Pradeep, A. K.; Gurumoorthy, R.

1994-01-01

In this paper we present a variety of nonlinear controllers for the magnetic bearing that ensure both stability and robustness. We utilize techniques of discontinuous control to design novel control laws for the magnetic bearing. We present in particular sliding mode controllers, time optimal controllers, winding algorithm based controllers, nested switching controllers, fractional controllers, and synchronous switching controllers for the magnetic bearing. We show existence of solutions to systems governed by discontinuous control laws, and prove stability and robustness of the chosen control laws in a rigorous setting. We design sliding mode observers for the magnetic bearing and prove the convergence of the state estimates to their true values. We present simulation results of the performance of the magnetic bearing subject to the aforementioned control laws, and conclude with comments on design.

A new class of energy based control laws for revolute robot arms - Tracking control, robustness enhancement and adaptive control

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz, Kenneth; Bayard, David S.

1988-01-01

A class of joint-level control laws for all-revolute robot arms is introduced. The analysis is similar to the recently proposed energy Liapunov function approach except that the closed-loop potential function is shaped in accordance with the underlying joint space topology. By using energy Liapunov functions with the modified potential energy, a much simpler analysis can be used to show closed-loop global asymptotic stability and local exponential stability. When Coulomb and viscous friction and model parameter errors are present, a sliding-mode-like modification of the control law is proposed to add a robustness-enhancing outer loop. Adaptive control is also addressed within the same framework. A linear-in-the-parameters formulation is adopted, and globally asymptotically stable adaptive control laws are derived by replacing the model parameters in the nonadaptive control laws by their estimates.

Attractive manifold-based adaptive solar attitude control of satellites in elliptic orbits

NASA Astrophysics Data System (ADS)

Lee, Keum W.; Singh, Sahjendra N.

2011-01-01

The paper presents a novel noncertainty-equivalent adaptive (NCEA) control system for the pitch attitude control of satellites in elliptic orbits using solar radiation pressure (SRP). The satellite is equipped with two identical solar flaps to produce control moments. The adaptive law is based on the attractive manifold design using filtered signals for synthesis, which is a modification of the immersion and invariance (I&I) method. The control system has a modular controller-estimator structure and has separate tunable gains. A special feature of this NCEA law is that the trajectories of the satellite converge to a manifold in an extended state space, and the adaptive law recovers the performance of a deterministic controller. This recovery of performance cannot be obtained with certainty-equivalent adaptive (CEA) laws. Simulation results are presented which show that the NCEA law accomplishes precise attitude control of the satellite in an elliptic orbit, despite large parameter uncertainties.

Constrained dynamics approach for motion synchronization and consensus

NASA Astrophysics Data System (ADS)

Bhatia, Divya

In this research we propose to develop constrained dynamical systems based stable attitude synchronization, consensus and tracking (SCT) control laws for the formation of rigid bodies. The generalized constrained dynamics Equations of Motion (EOM) are developed utilizing constraint potential energy functions that enforce communication constraints. Euler-Lagrange equations are employed to develop the non-linear constrained dynamics of multiple vehicle systems. The constraint potential energy is synthesized based on a graph theoretic formulation of the vehicle-vehicle communication. Constraint stabilization is achieved via Baumgarte's method. The performance of these constrained dynamics based formations is evaluated for bounded control authority. The above method has been applied to various cases and the results have been obtained using MATLAB simulations showing stability, synchronization, consensus and tracking of formations. The first case corresponds to an N-pendulum formation without external disturbances, in which the springs and the dampers connected between the pendulums act as the communication constraints. The damper helps in stabilizing the system by damping the motion whereas the spring acts as a communication link relaying relative position information between two connected pendulums. Lyapunov stabilization (energy based stabilization) technique is employed to depict the attitude stabilization and boundedness. Various scenarios involving different values of springs and dampers are simulated and studied. Motivated by the first case study, we study the formation of N 2-link robotic manipulators. The governing EOM for this system is derived using Euler-Lagrange equations. A generalized set of communication constraints are developed for this system using graph theory. The constraints are stabilized using Baumgarte's techniques. The attitude SCT is established for this system and the results are shown for the special case of three 2-link robotic manipulators. These methods are then applied to the formation of N-spacecraft. Modified Rodrigues Parameters (MRP) are used for attitude representation of the spacecraft because of their advantage of being a minimum parameter representation. Constrained non-linear equations of motion for this system are developed and stabilized using a Proportional-Derivative (PD) controller derived based on Baumgarte's method. A system of 3 spacecraft is simulated and the results for SCT are shown and analyzed. Another problem studied in this research is that of maintaining SCT under unknown external disturbances. We use an adaptive control algorithm to derive control laws for the actuator torques and develop an estimation law for the unknown disturbance parameters to achieve SCT. The estimate of the disturbance is added as a feed forward term in the actual control law to obtain the stabilization of a 3-spacecraft formation. The disturbance estimates are generated via a Lyapunov analysis of the closed loop system. In summary, the constrained dynamics method shows a lot of potential in formation control, achieving stabilization, synchronization, consensus and tracking of a set of dynamical systems.

Three different methods for the derivation of control laws for multi-degree-of-freedom systems containing electrorheological dampers

NASA Astrophysics Data System (ADS)

Moosheimer, Johannes; Waller, Heinz

1999-06-01

The minimization of unwanted vibrations is an important technical challenge. Purely passive systems often do not achieve the postulated results. Purely active systems are costly because of the required additional power and the necessary maintenance. Currently it seems that semi-active methods of vibration reduction are as competitive as any other methods. Semi-active damping control can be realized with electro- or magnetorheological fluids. These change their characteristic in the presence of an electric or magnetic field or by bypasses combined with magnetic valves. The methods known in linear control theory cannot be used for the controller design because no explicit external forces can be generated whenever they are needed. Forces can only be generated when relative velocities between the endpoints of the damper exist. It is important to investigate control methods which will reduce vibration with controlled damping. In this paper three different methods for establishing control laws are presented. The first is based on the consideration of power flow in the system. It is discussed in detail. The second method uses Bellmans dynamic optimization. The last transforms a multi degree of freedom system by modal analysis into uncoupled single degree of freedom systems. The control methods developed by these three methods all lead to the same vibration reduction strategy. The control laws are verified with simulation results.

Results of an integrated structure/control law design sensitivity analysis

NASA Technical Reports Server (NTRS)

Gilbert, Michael G.

1989-01-01

A design sensitivity analysis method for Linear Quadratic Cost, Gaussian (LQG) optimal control laws, which predicts change in the optimal control law due to changes in fixed problem parameters using analytical sensitivity equations is discussed. Numerical results of a design sensitivity analysis for a realistic aeroservoelastic aircraft example are presented. In this example, the sensitivity of the optimally controlled aircraft's response to various problem formulation and physical aircraft parameters is determined. These results are used to predict the aircraft's new optimally controlled response if the parameter was to have some other nominal value during the control law design process. The sensitivity results are validated by recomputing the optimal control law for discrete variations in parameters, computing the new actual aircraft response, and comparing with the predicted response. These results show an improvement in sensitivity accuracy for integrated design purposes over methods which do not include changes in the optimal control law. Use of the analytical LQG sensitivity expressions is also shown to be more efficient than finite difference methods for the computation of the equivalent sensitivity information.

Design and test of three active flutter suppression controllers

NASA Technical Reports Server (NTRS)

Christhilf, David M.; Waszak, Martin R.; Adams, William M.; Srinathkumar, S.; Mukhopadhyay, Vivek

1991-01-01

Three flutter suppression control law design techniques are presented. Each uses multiple control surfaces and/or sensors. The first uses linear combinations of several accelerometer signals together with dynamic compensation to synthesize the modal rate of the critical mode for feedback to distributed control surfaces. The second uses traditional tools (pole/zero loci and Nyquist diagrams) to develop a good understanding of the flutter mechanism and produce a controller with minimal complexity and good robustness to plant uncertainty. The third starts with a minimum energy Linear Quadratic Gaussian controller, applies controller order reduction, and then modifies weight and noise covariance matrices to improve multi-variable robustness. The resulting designs were implemented digitally and tested subsonically on the Active Flexible Wing (AFW) wind tunnel model. Test results presented here include plant characteristics, maximum attained closed-loop dynamic pressure, and Root Mean Square control surface activity. A key result is that simultaneous symmetric and antisymmetric flutter suppression was achieved by the second control law, with a 24 percent increase in attainable dynamic pressure.

Active damping using a control structure interaction approach

NASA Astrophysics Data System (ADS)

Umland, Jeffrey W.

1991-12-01

The vibration control of flexible structures using electromagnetic actuators is investigated. A model of an electromagnetic voice coil actuator is developed from elementary theory, and the required parameters are measured. Given a constant magnetic field, the force output of the voice coil varies linearly with the current flowing through the coil. The primary damping mechanism of the actuator used is found to be Coulomb friction. It is seen that Coulomb friction inhibits the response of the actuator to low levels of excitation. It is also seen that the actuator displayed a nonlinear relationship between force and current indicating that the applied magnetic field was not constant. This nonlinearity leads to a closed loop instability. Several design improvements are considered. Four different feedback control laws are developed to add active damping to a structure. The actuator is used as both a point force source and as a link in a mechanism that applies bending moments at two places on the structure. The actuator is used as both a point force source and as a link in a mechanism that applies bending moments at two places on the structure. The first control law uses the actuator as a traditional passive vibration absorber. The second control law is direct structural velocity feedback plus direct proof mass position feedback. The third control strategy is also direct structural velocity feedback but using compensated feedback of the proof mass position. The compensator is designed according to an H infinity optimization technique. The fourth control law uses the actuator as an equivalent mechanical viscous damper connected to two points on the structure. The results show that using direct structural velocity feedback provides improved vibration suppression in comparison to a traditional vibration absorber. Furthermore, the tuning criteria is only restricted to maintaining the actuator's single degree of freedom natural frequency below those of the structure to which it is attached.

43 CFR 4120.5-2 - Cooperation with Tribal, state, county, and Federal agencies.

Code of Federal Regulations, 2011 CFR

2011-10-01

... laws and regulations relating to livestock, livestock diseases, sanitation, and noxious weeds... 1971 (16 U.S.C. 1331 et seq.); (b) County or other local weed control districts in analyzing noxious weed problems and developing control programs for areas of the public lands and other lands...

Application of real-time engine simulations to the development of propulsion system controls

NASA Technical Reports Server (NTRS)

Szuch, J. R.

1975-01-01

The development of digital controls for turbojet and turbofan engines is presented by the use of real-time computer simulations of the engines. The engine simulation provides a test-bed for evaluating new control laws and for checking and debugging control software and hardware prior to engine testing. The development and use of real-time, hybrid computer simulations of the Pratt and Whitney TF30-P-3 and F100-PW-100 augmented turbofans are described in support of a number of controls research programs at the Lewis Research Center. The role of engine simulations in solving the propulsion systems integration problem is also discussed.

Participation in the Analysis of the Far-Infrared/Submillmeter Interferometer

NASA Technical Reports Server (NTRS)

Lorenzini, Enrico C.

2005-01-01

We have contributed to the development of the Submillimiter Probe of the Evolution of Cosmic Structure (SPECS) by analyzing various aspects related to the tethers that connect the spacecraft of this space interferometer. We have focused our analysis on key topics as follows: (a) helping in the configuration selection; (b) computing the system eigenfrequencies as a function of baseline length; (c) developing techniques and conceptual design of devices for damping the tether oscillations; (d) carrying out numerical simulations of tethered formation to assess the effects of environmental perturbations upon the baseline length variation; (e) developing control laws for reconfiguring the baseline length; (f) devising control laws for fast retargeting of the interferometer at moderate baseline lengths; (g) estimating the survivability to micrometeoroid impacts of a tether at L2; and (h) developing a conceptual design of a high- strength and survivable tether. The work was conducted for NASA Goddard Space Flight Center under Grant NNG04GQ21G with William Danchi as technical monitor.

Legal aspects of genetic information.

PubMed Central

Andrews, L. B.

1991-01-01

The federally funded Human Genome Initiative will lead to the development of new capabilities to learn about an individual's genetic status. Legal issues are raised concerning patients' and other parties' access to that information. This article discusses the effect of existing statutes and case law on three pivotal questions: To what sort of information are people entitled? What control should people have over their genetic information? Do people have a right to refuse genetic information? The article emphasizes that the law protects a patient's right to obtain or refuse genetic information about oneself, as well as the right to control the dissemination of that information to others. PMID:1897258

NASA Aircraft Controls Research, 1983

NASA Technical Reports Server (NTRS)

Beasley, G. P. (Compiler)

1984-01-01

The workshop consisted of 24 technical presentations on various aspects of aircraft controls, ranging from the theoretical development of control laws to the evaluation of new controls technology in flight test vehicles. A special report on the status of foreign aircraft technology and a panel session with seven representatives from organizations which use aircraft controls technology were also included. The controls research needs and opportunities for the future as well as the role envisioned for NASA in that research were addressed. Input from the panel and response to the workshop presentations will be used by NASA in developing future programs.

A Comparative Study of Obsessionality in Medical Students, Law Students, and Controls.

PubMed

Harries, Michael D; Kim, Suck Won; Grant, Jon E

2017-09-01

Understanding obsessive-compulsive behavior in medical students and law students is necessary for administrators and educators to properly work with students struggling with obsessionality. We aim to compare the differences in obsessive symptoms between medical students, law students and a control population. A total of 100 third-year medical students, 102 third-year law students and 103 control subjects drawn from the general population completed the Leyton Obsessional Inventory (LOI). Subjects were examined on all three sections (symptoms/traits, resistance and interference) of the LOI. Obsessional symptom scores for medical students (14.29 ± 7.33) and law students (13.65 ± 6.61) were significantly greater than for the control group (11.58 ± 7.45). Medical and law students were both more likely to report checking, order, routine and attention to detail as obsessive symptoms. Medical students were more likely than law students to possess the obsessive symptoms of cleanliness and conscientiousness, while law students were more likely than medical students to possess obsessive symptoms related to difficulty in making up their mind and doubting themselves. While medical students and law students are more obsessional than the control population, each group is more likely to report different obsessive symptoms.

Automatic control of cryogenic wind tunnels

NASA Technical Reports Server (NTRS)

Balakrishna, S.

1989-01-01

Inadequate Reynolds number similarity in testing of scaled models affects the quality of aerodynamic data from wind tunnels. This is due to scale effects of boundary-layer shock wave interaction which is likely to be severe at transonic speeds. The idea of operation of wind tunnels using test gas cooled to cryogenic temperatures has yielded a quantrum jump in the ability to realize full scale Reynolds number flow similarity in small transonic tunnels. In such tunnels, the basic flow control problem consists of obtaining and maintaining the desired test section flow parameters. Mach number, Reynolds number, and dynamic pressure are the three flow parameters that are usually required to be kept constant during the period of model aerodynamic data acquisition. The series of activity involved in modeling, control law development, mechanization of the control laws on a microcomputer, and the performance of a globally stable automatic control system for the 0.3-m Transonic Cryogenic Tunnel (TCT) are discussed. A lumped multi-variable nonlinear dynamic model of the cryogenic tunnel, generation of a set of linear control laws for small perturbation, and nonlinear control strategy for large set point changes including tunnel trajectory control are described. The details of mechanization of the control laws on a 16 bit microcomputer system, the software features, operator interface, the display and safety are discussed. The controller is shown to provide globally stable and reliable temperature control to + or - 0.2 K, pressure to + or - 0.07 psi and Mach number to + or - 0.002 of the set point value. This performance is obtained both during large set point commands as for a tunnel cooldown, and during aerodynamic data acquisition with intrusive activity like geometrical changes in the test section such as angle of attack changes, drag rake movements, wall adaptation and sidewall boundary-layer removal. Feasibility of the use of an automatic Reynolds number control mode with fixed Mach number control is demonstrated.

Nonlinear feedback guidance law for aero-assisted orbit transfer maneuvers

NASA Technical Reports Server (NTRS)

Menon, P. K. A.

1992-01-01

Aero-assisted orbit transfer vehicles have the potential for significantly reducing the fuel requirements in certain classes of orbit transfer operations. Development of a nonlinear feedback guidance law for performing aero-assisted maneuvers that accomplish simultaneous change of all the orbital elements with least vehicle acceleration magnitude is discussed. The analysis is based on a sixth order nonlinear point-mass vehicle model with lift, bank angle, thrust and drag modulation as the control variables. The guidance law uses detailed vehicle aerodynamic and the atmosphere models in the feedback loop. Higher-order gravitational harmonics, planetary atmosphere rotation and ambient winds are included in the formulation. Due to modest computational requirements, the guidance law is implementable on-board an orbit transfer vehicle. The guidance performance is illustrated for three sets of boundary conditions.

Transonic Flutter Suppression Control Law Design, Analysis and Wind-Tunnel Results

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

1999-01-01

The benchmark active controls technology and wind tunnel test program at NASA Langley Research Center was started with the objective to investigate the nonlinear, unsteady aerodynamics and active flutter suppression of wings in transonic flow. The paper will present the flutter suppression control law design process, numerical nonlinear simulation and wind tunnel test results for the NACA 0012 benchmark active control wing model. The flutter suppression control law design processes using classical, and minimax techniques are described. A unified general formulation and solution for the minimax approach, based on the steady state differential game theory is presented. Design considerations for improving the control law robustness and digital implementation are outlined. It was shown that simple control laws when properly designed based on physical principles, can suppress flutter with limited control power even in the presence of transonic shocks and flow separation. In wind tunnel tests in air and heavy gas medium, the closed-loop flutter dynamic pressure was increased to the tunnel upper limit of 200 psf. The control law robustness and performance predictions were verified in highly nonlinear flow conditions, gain and phase perturbations, and spoiler deployment. A non-design plunge instability condition was also successfully suppressed.

Workstation-Based Simulation for Rapid Prototyping and Piloted Evaluation of Control System Designs

NASA Technical Reports Server (NTRS)

Mansur, M. Hossein; Colbourne, Jason D.; Chang, Yu-Kuang; Aiken, Edwin W. (Technical Monitor)

1998-01-01

The development and optimization of flight control systems for modem fixed- and rotary-. wing aircraft consume a significant portion of the overall time and cost of aircraft development. Substantial savings can be achieved if the time required to develop and flight test the control system, and the cost, is reduced. To bring about such reductions, software tools such as Matlab/Simulink are being used to readily implement block diagrams and rapidly evaluate the expected responses of the completed system. Moreover, tools such as CONDUIT (CONtrol Designer's Unified InTerface) have been developed that enable the controls engineers to optimize their control laws and ensure that all the relevant quantitative criteria are satisfied, all within a fully interactive, user friendly, unified software environment.

A Nonlinear Physics-Based Optimal Control Method for Magnetostrictive Actuators

NASA Technical Reports Server (NTRS)

Smith, Ralph C.

1998-01-01

This paper addresses the development of a nonlinear optimal control methodology for magnetostrictive actuators. At moderate to high drive levels, the output from these actuators is highly nonlinear and contains significant magnetic and magnetomechanical hysteresis. These dynamics must be accommodated by models and control laws to utilize the full capabilities of the actuators. A characterization based upon ferromagnetic mean field theory provides a model which accurately quantifies both transient and steady state actuator dynamics under a variety of operating conditions. The control method consists of a linear perturbation feedback law used in combination with an optimal open loop nonlinear control. The nonlinear control incorporates the hysteresis and nonlinearities inherent to the transducer and can be computed offline. The feedback control is constructed through linearization of the perturbed system about the optimal system and is efficient for online implementation. As demonstrated through numerical examples, the combined hybrid control is robust and can be readily implemented in linear PDE-based structural models.

Ground test for vibration control demonstrator

NASA Astrophysics Data System (ADS)

Meyer, C.; Prodigue, J.; Broux, G.; Cantinaud, O.; Poussot-Vassal, C.

2016-09-01

In the objective of maximizing comfort in Falcon jets, Dassault Aviation is developing an innovative vibration control technology. Vibrations of the structure are measured at several locations and sent to a dedicated high performance vibration control computer. Control laws are implemented in this computer to analyse the vibrations in real time, and then elaborate orders sent to the existing control surfaces to counteract vibrations. After detailing the technology principles, this paper focuses on the vibration control ground demonstration that was performed by Dassault Aviation in May 2015 on Falcon 7X business jet. The goal of this test was to attenuate vibrations resulting from fixed forced excitation delivered by shakers. The ground test demonstrated the capability to implement an efficient closed-loop vibration control with a significant vibration level reduction and validated the vibration control law design methodology. This successful ground test was a prerequisite before the flight test demonstration that is now being prepared. This study has been partly supported by the JTI CleanSky SFWA-ITD.

Piloted simulation study of the effects of an automated trim system on flight characteristics of a light twin-engine airplane with one engine inoperative

NASA Technical Reports Server (NTRS)

Stewart, E. C.; Brown, P. W.; Yenni, K. R.

1986-01-01

A simulation study was conducted to investigate the piloting problems associated with failure of an engine on a generic light twin-engine airplane. A primary piloting problem for a light twin-engine airplane after an engine failure is maintaining precise control of the airplane in the presence of large steady control forces. To address this problem, a simulated automatic trim system which drives the trim tabs as an open-loop function of propeller slipstream measurements was developed. The simulated automatic trim system was found to greatly increase the controllability in asymmetric powered flight without having to resort to complex control laws or an irreversible control system. However, the trim-tab control rates needed to produce the dramatic increase in controllability may require special design consideration for automatic trim system failures. Limited measurements obtained in full-scale flight tests confirmed the fundamental validity of the proposed control law.

Adaptive critic designs for optimal control of uncertain nonlinear systems with unmatched interconnections.

PubMed

Yang, Xiong; He, Haibo

2018-05-26

In this paper, we develop a novel optimal control strategy for a class of uncertain nonlinear systems with unmatched interconnections. To begin with, we present a stabilizing feedback controller for the interconnected nonlinear systems by modifying an array of optimal control laws of auxiliary subsystems. We also prove that this feedback controller ensures a specified cost function to achieve optimality. Then, under the framework of adaptive critic designs, we use critic networks to solve the Hamilton-Jacobi-Bellman equations associated with auxiliary subsystem optimal control laws. The critic network weights are tuned through the gradient descent method combined with an additional stabilizing term. By using the newly established weight tuning rules, we no longer need the initial admissible control condition. In addition, we demonstrate that all signals in the closed-loop auxiliary subsystems are stable in the sense of uniform ultimate boundedness by using classic Lyapunov techniques. Finally, we provide an interconnected nonlinear plant to validate the present control scheme. Copyright © 2018 Elsevier Ltd. All rights reserved.

Nonlinear and Digital Man-machine Control Systems Modeling

NASA Technical Reports Server (NTRS)

Mekel, R.

1972-01-01

An adaptive modeling technique is examined by which controllers can be synthesized to provide corrective dynamics to a human operator's mathematical model in closed loop control systems. The technique utilizes a class of Liapunov functions formulated for this purpose, Liapunov's stability criterion and a model-reference system configuration. The Liapunov function is formulated to posses variable characteristics to take into consideration the identification dynamics. The time derivative of the Liapunov function generate the identification and control laws for the mathematical model system. These laws permit the realization of a controller which updates the human operator's mathematical model parameters so that model and human operator produce the same response when subjected to the same stimulus. A very useful feature is the development of a digital computer program which is easily implemented and modified concurrent with experimentation. The program permits the modeling process to interact with the experimentation process in a mutually beneficial way.

Development of an Automatic Ground Collision Avoidance System Using a Digital Terrain Database

DTIC Science & Technology

1989-12-01

release; distribution unlimited I I I I The purpose of this study was to develop a working control system that would perform automatic ground... control system analysis. I also wish to extend a hand of appreciation to my sponsor Mr. I Finley Barfield of the Flight Dynamics Laboratory for the use of...facilities, as- sistance in deciphering control law diagrams, and his expert knowledge of the F-16. Under the area of morale, I wish to thank all of my

Experiences with Ada in an embedded system

NASA Technical Reports Server (NTRS)

Labaugh, Robert J.

1988-01-01

Recent experiences with using Ada in a real time environment are described. The application was the control system for an experimental robotic arm. The objectives of the effort were to experiment with developing embedded applications in Ada, evaluating the suitability of the language for the application, and determining the performance of the system. Additional objectives were to develop a control system based on the NASA/NBS Standard Reference Model for Telerobot Control System Architecture (NASREM) in Ada, and to experiment with the control laws and how to incorporate them into the NASREM architecture.

Extended cooperative control synthesis

NASA Technical Reports Server (NTRS)

Davidson, John B.; Schmidt, David K.

1994-01-01

This paper reports on research for extending the Cooperative Control Synthesis methodology to include a more accurate modeling of the pilot's controller dynamics. Cooperative Control Synthesis (CCS) is a methodology that addresses the problem of how to design control laws for piloted, high-order, multivariate systems and/or non-conventional dynamic configurations in the absence of flying qualities specifications. This is accomplished by emphasizing the parallel structure inherent in any pilot-controlled, augmented vehicle. The original CCS methodology is extended to include the Modified Optimal Control Model (MOCM), which is based upon the optimal control model of the human operator developed by Kleinman, Baron, and Levison in 1970. This model provides a modeling of the pilot's compensation dynamics that is more accurate than the simplified pilot dynamic representation currently in the CCS methodology. Inclusion of the MOCM into the CCS also enables the modeling of pilot-observation perception thresholds and pilot-observation attention allocation affects. This Extended Cooperative Control Synthesis (ECCS) allows for the direct calculation of pilot and system open- and closed-loop transfer functions in pole/zero form and is readily implemented in current software capable of analysis and design for dynamic systems. Example results based upon synthesizing an augmentation control law for an acceleration command system in a compensatory tracking task using the ECCS are compared with a similar synthesis performed by using the original CCS methodology. The ECCS is shown to provide augmentation control laws that yield more favorable, predicted closed-loop flying qualities and tracking performance than those synthesized using the original CCS methodology.

The National Shipbuilding Research Program, Proceedings of the REAPS Technical Symposium Paper No. 1: Ship Production Committee Panel Overviews

DTIC Science & Technology

1980-10-01

Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law ...25 (4). April. 9. Vaughn and Allen, "The Development of Production Control in Ship- building", Kongsberg Japan Fabrils , Shipbuilding Symposium. Con...consistent with the law . • Participate in activities of voluntary standards bodies when such is in the public interest. • Coordinate agency

Creep rupture analysis of a beam resting on high temperature foundation

NASA Technical Reports Server (NTRS)

Gu, Randy J.; Cozzarelli, Francis A.

1988-01-01

A simplified uniaxial strain controlled creep damage law is deduced with the use of experimental observation from a more complex strain dependent law. This creep damage law correlates the creep damage, which is interpreted as the density variation in the material, directly with the accumulated creep strain. Based on the deduced uniaxial strain controlled creep damage law, a continuum mechanical creep rupture analysis is carried out for a beam resting on a high temperature elastic (Winkler) foundation. The analysis includes the determination of the nondimensional time for initial rupture, the propagation of the rupture front with the associated thinning of the beam, and the influence of creep damage on the deflection of the beam. Creep damage starts accumulating in the beam as soon as the load is applied, and a creep rupture front develops at and propagates from the point at which the creep damage first reaches its critical value. By introducing a series of fundamental assumptions within the framework of technical Euler-Bernoulli type beam theory, a governing set of integro-differential equations is derived in terms of the nondimensional bending moment and the deflection. These governing equations are subjected to a set of interface conditions at the propagating rupture front. A numerical technique is developed to solve the governing equations together with the interface equations, and the computed results are presented and discussed in detail.

Environmental Law Deskbook

DTIC Science & Technology

1998-06-12

public health threats posed by water pollution. (b) More effective control of polluted runoff (including a strategy for achieving a net gain of... Control Strategies for Toxic Pollutants. a. The CWA requires states to identify "impaired" water bodies within their boundaries. For water...standards. Thereafter, states must develop "individual control strategies " (ICSs) to regulate such pollutants and achieve water quality standards

Environmental Law

DTIC Science & Technology

2005-09-01

the Interior’s Bureau of Land Management (BLM). Flue - Gas Desulfurization (FGD). Post-combustion sulfur dioxide control technology in which a...8 (3) Special “transitional” classifications will be assigned to eligible areas participating in regional emission control strategies . b) Ozone...42 U.S.C. § 7411(f). C. States develop control strategies in their SIPs to achieve compliance with the NAAQS, but the federal government promulgates

Speed Control Law for Precision Terminal Area In-Trail Self Spacing

NASA Technical Reports Server (NTRS)

Abbott, Terence S.

2002-01-01

This document describes a speed control law for precision in-trail airborne self-spacing during final approach. This control law was designed to provide an operationally viable means to obtain a desired runway threshold crossing time or minimum distance, one aircraft relative to another. The control law compensates for dissimilar final approach speeds between aircraft pairs and provides guidance for a stable final approach. This algorithm has been extensively tested in Monte Carlo simulation and has been evaluated in piloted simulation, with preliminary results indicating acceptability from operational and workload standpoints.

Efficient Control Law Simulation for Multiple Mobile Robots

DOE Office of Scientific and Technical Information (OSTI.GOV)

Driessen, B.J.; Feddema, J.T.; Kotulski, J.D.

1998-10-06

In this paper we consider the problem of simulating simple control laws involving large numbers of mobile robots. Such simulation can be computationally prohibitive if the number of robots is large enough, say 1 million, due to the 0(N2 ) cost of each time step. This work therefore uses hierarchical tree-based methods for calculating the control law. These tree-based approaches have O(NlogN) cost per time step, thus allowing for efficient simulation involving a large number of robots. For concreteness, a decentralized control law which involves only the distance and bearing to the closest neighbor robot will be considered. The timemore » to calculate the control law for each robot at each time step is demonstrated to be O(logN).« less

Public health law and the prevention and control of obesity.

PubMed

Dietz, William H; Benken, Donald E; Hunter, Alicia S

2009-03-01

Obesity constitutes a major public health challenge in the United States. Obesogenic environments have increased owing to the consumption of calorie-dense foods of low nutritional value and the reduction of daily physical activity (e.g., increased portion sizes of meals eaten in and out of the home and fewer physical activity requirements in schools). Policymakers and public health practitioners need to know the best practices and have the competencies to use laws and legal authorities to reverse the obesity epidemic. For instance, statutes and regulations at the federal, state, and local levels of government have been implemented to improve nutritional choices and access to healthy foods, encourage physical activity, and educate consumers about adopting healthy lifestyles. In an effort to understand the application of laws and legal authorities for obesity prevention and control, in June 2008 the Centers for Disease Control and Prevention convened the National Summit on Legal Preparedness for Obesity Prevention and Control. An outcome of this summit will be the publication of the proceeding's white papers written by eight law and subject-matter experts with substantive contributions from summit participants, which will identify actionable options that sectors and organizations at various jurisdictional levels can consider adopting. Law has played a critical role in the control of chronic diseases and the behaviors that lead to them. The use of a systematic legal framework--the use of legislation, regulation, and policy to address the multiple factors that contribute to obesogenic environments--can assist in the development, implementation, and evaluation of a variety of legal approaches for obesity prevention and control. Although public health-focused legal interventions are in an early stage and the direct and indirect impact they may have on the obesity epidemic is not yet understood, efforts such as the summit and white papers should help determine potentially viable legal interventions and assess their impact on population-level change.

Use of ILTV Control Laws for LaNCETS Flight Research

NASA Technical Reports Server (NTRS)

Moua, Cheng

2010-01-01

A report discusses the Lift and Nozzle Change Effects on Tail Shock (LaNCETS) test to investigate the effects of lift distribution and nozzle-area ratio changes on tail shock strength of an F-15 aircraft. Specific research objectives are to obtain inflight shock strength for multiple combinations of nozzle-area ratio and lift distribution; compare results with preflight prediction tools; and update predictive tools with flight results. The objectives from a stability and control perspective are to ensure adequate aircraft stability for the changes in lift distribution and plume shape, and ensure manageable transient from engaging and disengaging the ILTV research control laws. In order to change the lift distribution and plume shape of the F-15 aircraft, a decade-old Inner Loop Thrust Vectoring (ILTV) research control law was used. Flight envelope expansion was performed for the test configuration and flight conditions prior to the probing test points. The approach for achieving the research objectives was to utilize the unique capabilities of NASA's NF-15B-837 aircraft to allow the adjustment of the nozzle-area ratio and/or canard positions by engaging the ILTV research control laws. The ILTV control laws provide the ability to add trim command biases to canard positions, nozzle area ratios, and thrust vectoring through the use of datasets. Datasets consist of programmed test inputs (PTIs) that define trims to change the nozzle-area ratio and/or canard positions. The trims are applied as increments to the normally commanded positions. A LaNCETS non-linear, six-degrees-of-freedom simulation capable of realtime pilot-in-the-loop, hardware-in-the-loop, and non-real-time batch support was developed and validated. Prior to first flight, extensive simulation analyses were performed to show adequate stability margins with the changes in lift distribution and plume shape. Additionally, engagement/disengagement transient analysis was also performed to show manageable transients.

Public Health Law and the Prevention and Control of Obesity

PubMed Central

Dietz, William H; Benken, Donald E; Hunter, Alicia S

2009-01-01

Context: Obesity constitutes a major public health challenge in the United States. Obesogenic environments have increased owing to the consumption of calorie-dense foods of low nutritional value and the reduction of daily physical activity (e.g., increased portion sizes of meals eaten in and out of the home and fewer physical activity requirements in schools). Policymakers and public health practitioners need to know the best practices and have the competencies to use laws and legal authorities to reverse the obesity epidemic. For instance, statutes and regulations at the federal, state, and local levels of government have been implemented to improve nutritional choices and access to healthy foods, encourage physical activity, and educate consumers about adopting healthy lifestyles. Methods: In an effort to understand the application of laws and legal authorities for obesity prevention and control, in June 2008 the Centers for Disease Control and Prevention convened the National Summit on Legal Preparedness for Obesity Prevention and Control. An outcome of this summit will be the publication of the proceeding's white papers written by eight law and subject-matter experts with substantive contributions from summit participants, which will identify actionable options that sectors and organizations at various jurisdictional levels can consider adopting. Findings: Law has played a critical role in the control of chronic diseases and the behaviors that lead to them. The use of a systematic legal framework—the use of legislation, regulation, and policy to address the multiple factors that contribute to obesogenic environments—can assist in the development, implementation, and evaluation of a variety of legal approaches for obesity prevention and control. Conclusions: Although public health–focused legal interventions are in an early stage and the direct and indirect impact they may have on the obesity epidemic is not yet understood, efforts such as the summit and white papers should help determine potentially viable legal interventions and assess their impact on population-level change. PMID:19298421

Digest of impaired driving and selected beverage control laws

DOT National Transportation Integrated Search

2007-08-01

This digest reports the status of State laws that are concerned with impaired driving offenses and alcoholic beverage control. Unless otherwise indicated, the status of the laws reported is January 1, 2007.

Digest of impaired driving and selected beverage control laws

DOT National Transportation Integrated Search

2006-04-01

This digest reports the status of State laws that are concerned with impaired driving offenses and alcoholic beverage control. Unless otherwise indicated, the status of the laws reported is January 1, 2006.

Exact controllability for a Thermodiffusion System with locally distributed controls

NASA Astrophysics Data System (ADS)

de Moraes, F. G.; Schulz, R. A.; Soriano, J. A.

2018-03-01

In this work we establish a exact controllability result for a thermodiffusion system, modeled by Cattaneo's law, posed in a one-dimensional domain. In the present model the control mechanisms are effective in a small subinterval of the domain. To obtain the desired results, we prove an observability inequality for the adjoint system which, together with the multiplier methods and the Hilbert Uniqueness Method (HUM) developed by J.L. Lions, gives the controllability.

Application of the aerodynamic energy concept to flutter suppression and gust alleviation by use of active controls

NASA Technical Reports Server (NTRS)

Nissim, E.; Caspi, A.; Lottati, I.

1976-01-01

The effects of active controls on flutter suppression and gust alleviation of the Arava twin turboprop STOL transport and the Westwind twinjet business transport are investigated. The active control surfaces are introduced in pairs which include, in any chosen wing strip, a 20-percent chord leading-edge control and a 20-percent chord trailing-edge control. Each control surface is driven by a combined linear-rotational sensor system located on the activated strip. The control law is based on the concept of aerodynamic energy and utilizes previously optimized control law parameters based on two-dimensional aerodynamic theory. The best locations of the activated system along the span of the wing are determined for bending-moment alleviation, reduction in fuselage accelerations, and flutter suppression. The effectiveness of the activated system over a wide range of maximum control deflections is also determined. Two control laws are investigated. The first control law utilizes both rigid-body and elastic contributions of the motion. The second control law employs primarily the elastic contribution of the wing and leads to large increases in the activated control effectiveness as compared with the basic control law. The results indicate that flutter speed can be significantly increased (over 70 percent increase) and that the bending moment due to gust loading can be almost totally eliminated by a control system of about 10 to 20 percent span with reasonable control-surface rotations.

Rate-Based Model Predictive Control of Turbofan Engine Clearance

NASA Technical Reports Server (NTRS)

DeCastro, Jonathan A.

2006-01-01

An innovative model predictive control strategy is developed for control of nonlinear aircraft propulsion systems and sub-systems. At the heart of the controller is a rate-based linear parameter-varying model that propagates the state derivatives across the prediction horizon, extending prediction fidelity to transient regimes where conventional models begin to lose validity. The new control law is applied to a demanding active clearance control application, where the objectives are to tightly regulate blade tip clearances and also anticipate and avoid detrimental blade-shroud rub occurrences by optimally maintaining a predefined minimum clearance. Simulation results verify that the rate-based controller is capable of satisfying the objectives during realistic flight scenarios where both a conventional Jacobian-based model predictive control law and an unconstrained linear-quadratic optimal controller are incapable of doing so. The controller is evaluated using a variety of different actuators, illustrating the efficacy and versatility of the control approach. It is concluded that the new strategy has promise for this and other nonlinear aerospace applications that place high importance on the attainment of control objectives during transient regimes.

X-38 Experimental Controls Laws

NASA Technical Reports Server (NTRS)

Munday, Steve; Estes, Jay; Bordano, Aldo J.

2000-01-01

X-38 Experimental Control Laws X-38 is a NASA JSC/DFRC experimental flight test program developing a series of prototypes for an International Space Station (ISS) Crew Return Vehicle, often called an ISS "lifeboat." X- 38 Vehicle 132 Free Flight 3, currently scheduled for the end of this month, will be the first flight test of a modem FCS architecture called Multi-Application Control-Honeywell (MACH), originally developed by the Honeywell Technology Center. MACH wraps classical P&I outer attitude loops around a modem dynamic inversion attitude rate loop. The dynamic inversion process requires that the flight computer have an onboard aircraft model of expected vehicle dynamics based upon the aerodynamic database. Dynamic inversion is computationally intensive, so some timing modifications were made to implement MACH on the slower flight computers of the subsonic test vehicles. In addition to linear stability margin analyses and high fidelity 6-DOF simulation, hardware-in-the-loop testing is used to verify the implementation of MACH and its robustness to aerodynamic and environmental uncertainties and disturbances.

On the use of controls for subsonic transport performance improvement: Overview and future directions

NASA Technical Reports Server (NTRS)

Gilyard, Glenn; Espana, Martin

1994-01-01

Increasing competition among airline manufacturers and operators has highlighted the issue of aircraft efficiency. Fewer aircraft orders have led to an all-out efficiency improvement effort among the manufacturers to maintain if not increase their share of the shrinking number of aircraft sales. Aircraft efficiency is important in airline profitability and is key if fuel prices increase from their current low. In a continuing effort to improve aircraft efficiency and develop an optimal performance technology base, NASA Dryden Flight Research Center developed and flight tested an adaptive performance seeking control system to optimize the quasi-steady-state performance of the F-15 aircraft. The demonstrated technology is equally applicable to transport aircraft although with less improvement. NASA Dryden, in transitioning this technology to transport aircraft, is specifically exploring the feasibility of applying adaptive optimal control techniques to performance optimization of redundant control effectors. A simulation evaluation of a preliminary control law optimizes wing-aileron camber for minimum net aircraft drag. Two submodes are evaluated: one to minimize fuel and the other to maximize velocity. This paper covers the status of performance optimization of the current fleet of subsonic transports. Available integrated controls technologies are reviewed to define approaches using active controls. A candidate control law for adaptive performance optimization is presented along with examples of algorithm operation.

Adaptive Control Law Development for Failure Compensation Using Neural Networks on a NASA F-15 Aircraft

NASA Technical Reports Server (NTRS)

Burken, John J.

2005-01-01

This viewgraph presentation covers the following topics: 1) Brief explanation of Generation II Flight Program; 2) Motivation for Neural Network Adaptive Systems; 3) Past/ Current/ Future IFCS programs; 4) Dynamic Inverse Controller with Explicit Model; 5) Types of Neural Networks Investigated; and 6) Brief example

Designing propagation environments in forest and native plant nurseries

Treesearch

Thomas D. Landis

2013-01-01

Propagation environments are areas that have been modified for plant growth, and can be designed using the law of limiting factors. Identifying critical factors that are most limiting to optimal plant growth is helpful when developing both bareroot and container nurseries. Propagation environments can be categorized into minimally-controlled, semi-controlled, and fully...

Flight-test of the glide-slope track and flare-control laws for an automatic landing system for a powered-lift STOL airplane

NASA Technical Reports Server (NTRS)

Watson, D. M.; Hardy, G. H.; Warner, D. N., Jr.

1983-01-01

An automatic landing system was developed for the Augmentor Wing Jet STOL Research Airplane to establish the feasibility and examine the operating characteristics of a powered-lift STOL transport flying a steep, microwave landing system (MLS) glide slope to automatically land on a STOL port. The flight test results address the longitudinal aspects of automatic powered lift STOL airplane operation including glide slope tracking on the backside of the power curve, flare, and touchdown. Three different autoland control laws were evaluated to demonstrate the tradeoff between control complexity and the resulting performance. The flight test and simulation methodology used in developing conventional jet transport systems was applied to the powered-lift STOL airplane. The results obtained suggest that an automatic landing system for a powered-lift STOL airplane operating into an MLS-equipped STOL port is feasible. However, the airplane must be provided with a means of rapidly regulation lift to satisfactorily provide the glide slope tracking and control of touchdown sink rate needed for automatic landings.

Wetlands Law Tests Government Power.

ERIC Educational Resources Information Center

McGregor, Gregor I.

1992-01-01

Discusses how working definitions of wetlands vary in different statutes and the controversy this has created. Focuses on these definition differences in relationship to federal, state and local government control of environmental protection and development decisions. (MCO)

Safe Haven Laws as "Crime Control Theater"

ERIC Educational Resources Information Center

Hammond, Michelle; Miller, Monica K.; Griffin, Timothy

2010-01-01

Objectives: This article examines safe haven laws, which allow parents to legally abandon their infants. The main objective is to determine whether safe haven laws fit the criteria of "crime control theater", a term used to describe public policies that produce the appearance, but not the effect, of crime control, and as such are essentially…

Transonic Flutter Suppression Control Law Design, Analysis and Wind Tunnel Results

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

1999-01-01

The benchmark active controls technology and wind tunnel test program at NASA Langley Research Center was started with the objective to investigate the nonlinear, unsteady aerodynamics and active flutter suppression of wings in transonic flow. The paper will present the flutter suppression control law design process, numerical nonlinear simulation and wind tunnel test results for the NACA 0012 benchmark active control wing model. The flutter suppression control law design processes using (1) classical, (2) linear quadratic Gaussian (LQG), and (3) minimax techniques are described. A unified general formulation and solution for the LQG and minimax approaches, based on the steady state differential game theory is presented. Design considerations for improving the control law robustness and digital implementation are outlined. It was shown that simple control laws when properly designed based on physical principles, can suppress flutter with limited control power even in the presence of transonic shocks and flow separation. In wind tunnel tests in air and heavy gas medium, the closed-loop flutter dynamic pressure was increased to the tunnel upper limit of 200 psf The control law robustness and performance predictions were verified in highly nonlinear flow conditions, gain and phase perturbations, and spoiler deployment. A non-design plunge instability condition was also successfully suppressed.

Transonic Flutter Suppression Control Law Design, Analysis and Wind-Tunnel Results

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

1999-01-01

The benchmark active controls technology and wind tunnel test program at NASA Langley Research Center was started with the objective to investigate the nonlinear, unsteady aerodynamics and active flutter suppression of wings in transonic flow. The paper will present the flutter suppression control law design process, numerical nonlinear simulation and wind tunnel test results for the NACA 0012 benchmark active control wing model. The flutter suppression control law design processes using (1) classical, (2) linear quadratic Gaussian (LQG), and (3) minimax techniques are described. A unified general formulation and solution for the LQG and minimax approaches, based on the steady state differential game theory is presented. Design considerations for improving the control law robustness and digital implementation are outlined. It was shown that simple control laws when properly designed based on physical principles, can suppress flutter with limited control power even in the presence of transonic shocks and flow separation. In wind tunnel tests in air and heavy gas medium, the closed-loop flutter dynamic pressure was increased to the tunnel upper limit of 200 psf. The control law robustness and performance predictions were verified in highly nonlinear flow conditions, gain and phase perturbations, and spoiler deployment. A non-design plunge instability condition was also successfully suppressed.

Transonic Flutter Suppression Control Law Design Using Classical and Optimal Techniques with Wind-Tunnel Results

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

1999-01-01

The benchmark active controls technology and wind tunnel test program at NASA Langley Research Center was started with the objective to investigate the nonlinear, unsteady aerodynamics and active flutter suppression of wings in transonic flow. The paper will present the flutter suppression control law design process, numerical nonlinear simulation and wind tunnel test results for the NACA 0012 benchmark active control wing model. The flutter suppression control law design processes using (1) classical, (2) linear quadratic Gaussian (LQG), and (3) minimax techniques are described. A unified general formulation and solution for the LQG and minimax approaches, based on the steady state differential game theory is presented. Design considerations for improving the control law robustness and digital implementation are outlined. It was shown that simple control laws when properly designed based on physical principles, can suppress flutter with limited control power even in the presence of transonic shocks and flow separation. In wind tunnel tests in air and heavy gas medium, the closed-loop flutter dynamic pressure was increased to the tunnel upper limit of 200 psf. The control law robustness and performance predictions were verified in highly nonlinear flow conditions, gain and phase perturbations, and spoiler deployment. A non-design plunge instability condition was also successfully suppressed.

Integration of Visual and Joint Information to Enable Linear Reaching Motions

NASA Astrophysics Data System (ADS)

Eberle, Henry; Nasuto, Slawomir J.; Hayashi, Yoshikatsu

2017-01-01

A new dynamics-driven control law was developed for a robot arm, based on the feedback control law which uses the linear transformation directly from work space to joint space. This was validated using a simulation of a two-joint planar robot arm and an optimisation algorithm was used to find the optimum matrix to generate straight trajectories of the end-effector in the work space. We found that this linear matrix can be decomposed into the rotation matrix representing the orientation of the goal direction and the joint relation matrix (MJRM) representing the joint response to errors in the Cartesian work space. The decomposition of the linear matrix indicates the separation of path planning in terms of the direction of the reaching motion and the synergies of joint coordination. Once the MJRM is numerically obtained, the feedfoward planning of reaching direction allows us to provide asymptotically stable, linear trajectories in the entire work space through rotational transformation, completely avoiding the use of inverse kinematics. Our dynamics-driven control law suggests an interesting framework for interpreting human reaching motion control alternative to the dominant inverse method based explanations, avoiding expensive computation of the inverse kinematics and the point-to-point control along the desired trajectories.

Development of Standard Methods of Testing and Analyzing Fatigue Crack Growth Rate Data

DTIC Science & Technology

1978-05-01

nitrogen cooled cryostat; high temperature tests were conducted using resistance heating tapes . An automatic controller maintained test temperatures...Cracking," Int. J. Fracture, Vol. 9, 1973, pp. 63-74. 87. P. Paris and F. Erdogan , "A Critical Analysis of Crack Propagation Laws," Trans. ASME, Ser. D: J...requirements of Sec. 7.2 and Appendix B. 200 REFERENCES 1. P. C. Paris and F. Erdogan , "A Critical Analysis of Crack Propagation Laws", Trans. ASME, Ser. D: 3

The "first digit law" - A hypothesis on its possible impact on medicine and development aid.

PubMed

Pollach, Gregor; Brunkhorst, Frank; Mipando, Mwapatsa; Namboya, Felix; Mndolo, Samson; Luiz, Thomas

2016-12-01

The "first digit law" or "Benford's law" is a mathematical distribution discovered by Simon Newcomb and Frank Benford. It states, that the probability of the leading number d (d∈{1,…,9}) in many natural datasets follows: P (d)=log 10 (d+1)-log 10 (d)=log 10 (1+1/d). It was successfully used through tax authorities and "forensic accounting" in order to detect fraud and other irregularities. Benfords law was almost neglected for its use outside financial accounting. The planning for health care systems in developing countries is extremely dependant on good, valid data. Whether you plan the catchment area for the future district hospitals, the number of health posts, the staff establishment for the central hospital or the drug budget in the Ministry. The "first digit law" can be used in medicine, public health, physiology and development aid to unmask questionable data, to discover unexpected challenges, difficulties in the data collection process, loss through corruption and criminal fraud. Our hypothesis suggests, that the "first digit law" is a cost effective tool, which is easy to use for most people in the medical profession, which does not really needs complicated statistical software and can be used on the spot, even in the resource restricted conditions of developing countries. Several preconditions (like the size of the data set and its reach over more than two dimensions) have to be fulfilled, but then Benfords law can be used by any clinician, physiologist, public health specialist or aid consultant without difficulties and without deeper statistical knowledge in the four steps, we suggest in this article. The consequences will be different depending on the level (local regional, national, continental, international) on which you will use the law. All levels will be enabled to get insight into the validity of the data-challenges for the other levels without the help of trained statisticians or accountants. We believe that the "first digit law" is a vastly underestimated and neglected, but extremely useful tool for the identification of unexpected challenges, supervision and control in various parts of medicine and public health for almost all aspects of development aid. Copyright © 2016 Elsevier Ltd. All rights reserved.

Environmental Law

DTIC Science & Technology

2001-12-04

criteria for water bodies within the state. 4. Individual Control Strategies for Toxic Pollutants. a. The CWA requires states to identify...preventing or impeding the achievement of water quality standards. Thereafter, states must develop “individual control strategies ” (ICSs) to regulate...standards will be met not later than three years after the individual control strategy is established.” 40 C.F.R. § 123.46(c). (1) As a result

Systems-on-chip approach for real-time simulation of wheel-rail contact laws

NASA Astrophysics Data System (ADS)

Mei, T. X.; Zhou, Y. J.

2013-04-01

This paper presents the development of a systems-on-chip approach to speed up the simulation of wheel-rail contact laws, which can be used to reduce the requirement for high-performance computers and enable simulation in real time for the use of hardware-in-loop for experimental studies of the latest vehicle dynamic and control technologies. The wheel-rail contact laws are implemented using a field programmable gate array (FPGA) device with a design that substantially outperforms modern general-purpose PC platforms or fixed architecture digital signal processor devices in terms of processing time, configuration flexibility and cost. In order to utilise the FPGA's parallel-processing capability, the operations in the contact laws algorithms are arranged in a parallel manner and multi-contact patches are tackled simultaneously in the design. The interface between the FPGA device and the host PC is achieved by using a high-throughput and low-latency Ethernet link. The development is based on FASTSIM algorithms, although the design can be adapted and expanded for even more computationally demanding tasks.

Analysis of airframe/engine interactions - An integrated control perspective

NASA Technical Reports Server (NTRS)

Schmidt, David K.; Schierman, John D.; Garg, Sanjay

1990-01-01

Techniques for the analysis of the dynamic interactions between airframe/engine dynamical systems are presented. Critical coupling terms are developed that determine the significance of these interactions with regard to the closed loop stability and performance of the feedback systems. A conceptual model is first used to indicate the potential sources of the coupling, how the coupling manifests itself, and how the magnitudes of these critical coupling terms are used to quantify the effects of the airframe/engine interactions. A case study is also presented involving an unstable airframe with thrust vectoring for attitude control. It is shown for this system with classical, decentralized control laws that there is little airframe/engine interaction, and the stability and performance with those control laws is not affected. Implications of parameter uncertainty in the coupling dynamics is also discussed, and effects of these parameter variations are also demonstrated to be small for this vehicle configuration.

Analytical investigation of the dynamics of tethered constellations in Earth orbit, phase 2

NASA Technical Reports Server (NTRS)

Lorenzini, Enrico C.

1987-01-01

A control law was developed to control the elevator during short-distance maneuvers along the tether of a 4-mass tethered system. This control law (called retarded exponential or RE) was analyzed parametrically in order to assess which control parameters provide a good dynamic response and a smooth time history of the acceleration on board the elevator. The short-distance maneuver under investigation consists of a slow crawling of the elevator over the distance of 10 m that represents a typical maneuver for fine tuning the acceleration level on board the elevator. The contribution of aerodynamic and thermal perturbations upon acceleration levels was also evaluated and acceleration levels obtained when such pertubations are taken into account were compared to those obtained by neglecting the thermal and aerodynamic forces. In addition, the preparation of a tether simulation questionnaire is illustrated. Analytic solutions to be compared to numerical cases and simulator test cases are also discussed.

78 FR 49282 - Renewal of Agency Information Collection for Reporting Systems for Public Law 102-477...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-13

... System for Public Law 102-477 Demonstration Project authorized by OMB Control Number 1076-0135. This... OMB Control Number 1076-0135, Reporting System for Public Law 102-477 Demonstration Project. This... public review, we cannot guarantee that we will be able to do so. III. Data OMB Control Number: 1076-0135...

Ride quality sensitivity to SAS control law and to handling quality variations

NASA Technical Reports Server (NTRS)

Roberts, P. A.; Schmidt, D. K.; Swaim, R. L.

1976-01-01

The RQ trends which large flexible aircraft exhibit under various parameterizations of control laws and handling qualities are discussed. A summary of the assumptions and solution technique, a control law parameterization review, a discussion of ride sensitivity to handling qualities, and the RQ effects generated by implementing relaxed static stability configurations are included.

Hubble Space Telescope Reduced-Gyro Control Law Design, Implementation, and On-Orbit Performance

NASA Technical Reports Server (NTRS)

Clapp, Brian R.; Ramsey, Patrick R.; Wirzburger, John H.; Smith, Daniel C.; VanArsadall, John C.

2008-01-01

Following gyro failures in April 2001 and April 2003, HST Pointing Control System engineers designed reduced-gyro control laws to extend the spacecraft science mission. The Two-Gyro Science (TGS) and One-Gyro Science (OGS) control laws were designed and implemented using magnetometers, star trackers, and Fine Guidance Sensors in succession to control vehicle rate about the missing gyro axes. Both TGS and OGS have demonstrated on-orbit pointing stability of 7 milli-arcseconds or less, which depends upon the guide star magnitude used by the Fine Guidance Sensor. This paper describes the design, implementation, and on-orbit performance of the TGS and OGS control law fine-pointing modes using Fixed Head Star Trackers and Fine Guidance Sensors, after successfully achieving coarse-pointing control using magnetometers.

Synthesis and implementation of state-trajectory control law for dc-to-dc converters

NASA Technical Reports Server (NTRS)

Burns, W. W., III; Huffman, S. D.; Wilson, T. G.; Owen, H. A., Jr.

1977-01-01

Mathematical representations of a state-plane switching boundary employed in a state-trajectory control law for dc-to-dc converters are derived. Two approaches to implementing the control law are discussed; one approach employs a digital processor and the other uses analog computational circuits. Performance characteristics of experimental voltage step-up dc-to-dc converters operating under the control of each of these implementations are presented.

Precision pointing and control of flexible spacecraft

NASA Technical Reports Server (NTRS)

Bantell, M. H., Jr.

1987-01-01

The problem and long term objectives for the precision pointing and control of flexible spacecraft are given. The four basic objectives are stated in terms of two principle tasks. Under Task 1, robust low order controllers, improved structural modeling methods for control applications and identification methods for structural dynamics are being developed. Under Task 2, a lab test experiment for verification of control laws and system identification algorithms is being developed. For Task 1, work has focused on robust low order controller design and some initial considerations for structural modeling in control applications. For Task 2, work has focused on experiment design and fabrication, along with sensor selection and initial digital controller implementation. Conclusions are given.

Decentralized digital adaptive control of robot motion

NASA Technical Reports Server (NTRS)

Tarokh, M.

1990-01-01

A decentralized model reference adaptive scheme is developed for digital control of robot manipulators. The adaptation laws are derived using hyperstability theory, which guarantees asymptotic trajectory tracking despite gross robot parameter variations. The control scheme has a decentralized structure in the sense that each local controller receives only its joint angle measurement to produce its joint torque. The independent joint controllers have simple structures and can be programmed using a very simple and computationally fast algorithm. As a result, the scheme is suitable for real-time motion control.

Design definition of the Laser Atmospheric Wind Sounder (LAWS), phase 2. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1992-01-01

The LAWS phase 1 and phase 2 studies have been completed on schedule and have led to significant advances in CO2 laser development. The Phase 2 Design Definition Study has shown that a large scanning mirror/high pulse energy laser LAWS Instrument is feasible and within the existing technology. The capability to monitor wind velocities with backscatter ratios of 10(exp 11) m(exp -1) SR(exp -1) is feasible. The weight budget allocated for the baseline LAWS is adequate, and sufficient reserves exist with the potential downsized configuration. With the possible decrease in available power from the baseline of 2.2 kW guideline, power and shot management is critical for the baseline configuration (15 to 20 J). This is particularly true during the 100 day occultation period each year. With the downsized configurations (5 to 7 J), power management is still necessary during the occultation but is primarily limited to shot management over the polar regions. The breadboard effort has produced significant laser advances for a tight 18 month schedule and the minimum budgets available from NASA, Lockheed, and TDS. Using the NASA funds and Lockheed and TDS fixed assets budgets, the breadboard was designed, fabricated, and brought on-line with first laser light within 16 months after ATP. First laser beam was obtained on 21 April 1992 at a 5 J power level. Tests since then have been conducted at sustained, repetitive pulse levels of over 7 J and 20 Hz. This is an increase of over two or three times greater than any system previously developed from this type laser. Increased power levels and additional life tests will be accomplished in the next LAWS phase. The Lockheed LAWS design will operate in the gravity gradient mode on-orbit, and all possible instrument vibration and jitter modes have been considered. Adequate pointing stability and control is state-of-the-art technology for the critical time periods, frequency rates, and control responses required by LAWS. Lockheed recommends a 6-1/2 year phase C/D program for LAWS to provide adequate feedback from the engineering unit and the qualification unit to the final flight unit. Assuming a one year period for LAWS integration to the spacecraft, followed by a six-month period for launch vehicle integration, LAWS could be successfully developed and launched in eight years. Our baseline design or downsized design can be accommodated by either the Atlas 2AS or the Delta launch vehicles. Lockheed's recommendation is that, based on the successful phase 2 design study and breadboard program, a follow-on 18 month extended breadboard testing program and additional system engineering studies, primarily in interfacing with a to be defined platform, be initiated. This should be immediately followed by the phase C/D program, leading to a LAWS launch in late 2001 or early 2002.

Robust control of combustion instabilities

NASA Astrophysics Data System (ADS)

Hong, Boe-Shong

Several interactive dynamical subsystems, each of which has its own time-scale and physical significance, are decomposed to build a feedback-controlled combustion- fluid robust dynamics. On the fast-time scale, the phenomenon of combustion instability is corresponding to the internal feedback of two subsystems: acoustic dynamics and flame dynamics, which are parametrically dependent on the slow-time-scale mean-flow dynamics controlled for global performance by a mean-flow controller. This dissertation constructs such a control system, through modeling, analysis and synthesis, to deal with model uncertainties, environmental noises and time- varying mean-flow operation. Conservation law is decomposed as fast-time acoustic dynamics and slow-time mean-flow dynamics, served for synthesizing LPV (linear parameter varying)- L2-gain robust control law, in which a robust observer is embedded for estimating and controlling the internal status, while achieving trade- offs among robustness, performances and operation. The robust controller is formulated as two LPV-type Linear Matrix Inequalities (LMIs), whose numerical solver is developed by finite-element method. Some important issues related to physical understanding and engineering application are discussed in simulated results of the control system.

On Mixed Data and Event Driven Design for Adaptive-Critic-Based Nonlinear $H_{\\infty}$ Control.

PubMed

Wang, Ding; Mu, Chaoxu; Liu, Derong; Ma, Hongwen

2018-04-01

In this paper, based on the adaptive critic learning technique, the control for a class of unknown nonlinear dynamic systems is investigated by adopting a mixed data and event driven design approach. The nonlinear control problem is formulated as a two-player zero-sum differential game and the adaptive critic method is employed to cope with the data-based optimization. The novelty lies in that the data driven learning identifier is combined with the event driven design formulation, in order to develop the adaptive critic controller, thereby accomplishing the nonlinear control. The event driven optimal control law and the time driven worst case disturbance law are approximated by constructing and tuning a critic neural network. Applying the event driven feedback control, the closed-loop system is built with stability analysis. Simulation studies are conducted to verify the theoretical results and illustrate the control performance. It is significant to observe that the present research provides a new avenue of integrating data-based control and event-triggering mechanism into establishing advanced adaptive critic systems.

Evaluating the effectiveness of state specific lead-based paint hazard risk reduction laws in preventing recurring incidences of lead poisoning in children.

PubMed

Kennedy, Chinaro; Lordo, Robert; Sucosky, Marissa Scalia; Boehm, Rona; Brown, Mary Jean

2016-01-01

Despite significant progress made in recent decades in preventing childhood lead poisoning in the United States through the control or elimination of lead sources in the environment, it continues to be an issue in many communities, primarily in low-income communities with a large percentage of deteriorating housing built before the elimination of lead in residential paint. The purpose of this study is to determine whether state laws aimed at preventing childhood lead poisoning are also effective in preventing recurring lead poisoning among children previously poisoned. An evaluation was conducted to determine whether laws in two representative states, Massachusetts and Ohio, have been effective in preventing recurrent lead poisoning among children less than 72 months of age previously poisoned, compared to a representative state (Mississippi) which at the time of the study had yet to develop legislation to prevent childhood lead poisoning. Compared to no legislation, unadjusted estimates showed children less than 72 months old, living in Massachusetts, previously identified as being lead poisoned, were 73% less likely to develop recurrent lead poisoning. However, this statistically significant association did not remain after controlling for other confounding variables. We did not find such a significant association when analyzing data from Ohio. While findings from unadjusted estimates indicated that state lead laws such as those in Massachusetts may be effective at preventing recurrent lead poisoning among young children, small numbers may have attenuated the power to obtain statistical significance during multivariate analysis. Our findings did not provide evidence that state lead laws, such as those in Ohio, were effective in preventing recurrent lead poisoning among young children. Further studies may be needed to confirm these findings. Published by Elsevier GmbH.

Evaluating the effectiveness of state specific lead-based paint hazard risk reduction laws in preventing recurring incidences of lead poisoning in children☆

PubMed Central

Kennedy, Chinaro; Lordo, Robert; Sucosky, Marissa Scalia; Boehm, Rona; Brown, Mary Jean

2016-01-01

Background Despite significant progress made in recent decades in preventing childhood lead poisoning in the United States through the control or elimination of lead sources in the environment, it continues to be an issue in many communities, primarily in low-income communities with a large percentage of deteriorating housing built before the elimination of lead in residential paint. The purpose of this study is to determine whether state laws aimed at preventing childhood lead poisoning are also effective in preventing recurring lead poisoning among children previously poisoned. Methods An evaluation was conducted to determine whether laws in two representative states, Massachusetts and Ohio, have been effective in preventing recurrent lead poisoning among children less than 72 months of age previously poisoned, compared to a representative state (Mississippi) which at the time of the study had yet to develop legislation to prevent childhood lead poisoning. Results Compared to no legislation, unadjusted estimates showed children less than 72 months old, living in Massachusetts, previously identified as being lead poisoned, were 73% less likely to develop recurrent lead poisoning. However, this statistically significant association did not remain after controlling for other confounding variables. We did not find such a significant association when analyzing data from Ohio. Conclusions While findings from unadjusted estimates indicated that state lead laws such as those in Massachusetts may be effective at preventing recurrent lead poisoning among young children, small numbers may have attenuated the power to obtain statistical significance during multivariate analysis. Our findings did not provide evidence that state lead laws, such as those in Ohio, were effective in preventing recurrent lead poisoning among young children. Further studies may be needed to confirm these findings. PMID:26472219

Spatial-temporal migration laws of Cd in Jiaozhou Bay

NASA Astrophysics Data System (ADS)

Yang, Dongfang; Li, Haixia; Zhang, Xiaolong; Wang, Qi; Miao, Zhenqing

2018-02-01

Many marine bays have been polluted by various pollutants, and understanding the migration laws is essential to scientific research and pollution control. This paper analyzed the spatial and temporal migration laws of Cd in waters in Jiaozhou Bay during 1979—1983. Results showed that there were twenty spatial-temporal migration law for the migration processes of Cd. These laws were helpful for better understanding the migration of Cd in marine bay, providing basis for scientific research and pollution control.

Initial Flight Test of the Production Support Flight Control Computers at NASA Dryden Flight Research Center

NASA Technical Reports Server (NTRS)

Carter, John; Stephenson, Mark

1999-01-01

The NASA Dryden Flight Research Center has completed the initial flight test of a modified set of F/A-18 flight control computers that gives the aircraft a research control law capability. The production support flight control computers (PSFCC) provide an increased capability for flight research in the control law, handling qualities, and flight systems areas. The PSFCC feature a research flight control processor that is "piggybacked" onto the baseline F/A-18 flight control system. This research processor allows for pilot selection of research control law operation in flight. To validate flight operation, a replication of a standard F/A-18 control law was programmed into the research processor and flight-tested over a limited envelope. This paper provides a brief description of the system, summarizes the initial flight test of the PSFCC, and describes future experiments for the PSFCC.

Site classification of ponderosa pine stands under stocking control in California

Treesearch

Robert F. Powers; William W. Oliver

1978-01-01

Existing systems for estimating site index of ponderosa pine (Pinus ponderosa Laws.) do not apply well to California stands where stocking is controlled. A more suitable system has been developed using trends in natural height growth, derived from stem analysis of dominant trees in California. This site index system produces polymorphic patterns of...

[Preparation of the database and the Internet (WWW) homepage for regulations on chemicals in Japan].

PubMed

Yamamoto, M; Morita, M; Kaminuma, T

1999-01-01

We prepared a database on chemical regulations in Japan. The regulations consist of "The Law concerning the Examination and Regulation of Manufacture, etc., of Chemical Substances", "Poisonous and Deleterious Substances", Control Law", "Waterworks Law", "Law for the Control of Household Products containing Harmful Substances", and Pesticide Residues in Food Sanitation Law". We also set up a World Wide Web (WWW) homepage containing an explanation of the law as well as chemical names, CAS registry numbers, and standards. The WWW pages contain lists of chemicals and the retrieval page for the database.

Feedback Implementation of Zermelo's Optimal Control by Sugeno Approximation

NASA Technical Reports Server (NTRS)

Clifton, C.; Homaifax, A.; Bikdash, M.

1997-01-01

This paper proposes an approach to implement optimal control laws of nonlinear systems in real time. Our methodology does not require solving two-point boundary value problems online and may not require it off-line either. The optimal control law is learned using the original Sugeno controller (OSC) from a family of optimal trajectories. We compare the trajectories generated by the OSC and the trajectories yielded by the optimal feedback control law when applied to Zermelo's ship steering problem.

Office of River Protection Advanced Low-Activity Waste Glass Research and Development Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peeler, David K.; Kim, Dong-Sang; Vienna, John D.

2015-11-01

The U.S. Department of Energy Office of River Protection (ORP) has initiated and leads an integrated Advanced Waste Glass (AWG) program to increase the loading of Hanford tank wastes in glass while meeting melter lifetime expectancies and process, regulatory, and product performance requirements. The integrated ORP program is focused on providing a technical, science-based foundation for making key decisions regarding the successful operation of the Hanford Tank Waste Treatment and Immobilization Plant (WTP) facilities in the context of an optimized River Protection Project (RPP) flowsheet. The fundamental data stemming from this program will support development of advanced glass formulations, keymore » product performance and process control models, and tactical processing strategies to ensure safe and successful operations for both the low-activity waste (LAW) and high-level waste vitrification facilities. These activities will be conducted with the objective of improving the overall RPP mission by enhancing flexibility and reducing cost and schedule. The purpose of this advanced LAW glass research and development plan is to identify the near-term, mid-term, and longer-term research and development activities required to develop and validate advanced LAW glasses, property-composition models and their uncertainties, and an advanced glass algorithm to support WTP facility operations, including both Direct Feed LAW and full pretreatment flowsheets. Data are needed to develop, validate, and implement 1) new glass property-composition models and 2) a new glass formulation algorithm. Hence, this plan integrates specific studies associated with increasing the Na2O and SO3/halide concentrations in glass, because these components will ultimately dictate waste loadings for LAW vitrification. Of equal importance is the development of an efficient and economic strategy for 99Tc management. Specific and detailed studies are being implemented to understand the fate of Tc throughout the WTP flowsheet and the underlying mechanisms that dictate its partitioning between streams within the LAW vitrification facility. These studies are aimed at increasing the single-pass Tc retention in glass and the potential use of high-temperature mineral phases to capture Tc. The Tc-bearing mineral phases would be thermally stable and resistant to Tc release during feed melting reactions or they could serve as alternative waste forms. The LAW glass research and development is focused on reducing the total volume of LAW glass produced and minimizing the impact of (or potentially eliminating) the need for recycle.« less

Time-Coordination Strategies and Control Laws for Multi-Agent Unmanned Systems

NASA Technical Reports Server (NTRS)

Puig-Navarro, Javier; Hovakimyan, Naira; Allen, B. Danette

2017-01-01

Time-critical coordination tools for unmanned systems can be employed to enforce the type of temporal constraints required in terminal control areas, ensure minimum distance requirements among vehicles are satisfied, and successfully perform coordinated missions. In comparison with previous literature, this paper presents an ampler spectrum of coordination and temporal specifications for unmanned systems, and proposes a general control law that can enforce this range of constraints. The constraint classification presented con- siders the nature of the desired arrival window and the permissible coordination errors to define six different types of time-coordination strategies. The resulting decentralized coordination control law allows the vehicles to negotiate their speeds along their paths in response to information exchanged over the communication network. This control law organizes the different members in the fleet hierarchically per their behavior and informational needs as reference agent, leaders, and followers. Examples and simulation results for all the coordination strategies presented demonstrate the applicability and efficacy of the coordination control law for multiple unmanned systems.

Investigation and Development of Control Laws for the NASA Langley Research Center Cockpit Motion Facility

NASA Technical Reports Server (NTRS)

Coon, Craig R.; Cardullo, Frank M.; Zaychik, Kirill B.

2014-01-01

The ability to develop highly advanced simulators is a critical need that has the ability to significantly impact the aerospace industry. The aerospace industry is advancing at an ever increasing pace and flight simulators must match this development with ever increasing urgency. In order to address both current problems and potential advancements with flight simulator techniques, several aspects of current control law technology of the National Aeronautics and Space Administration (NASA) Langley Research Center's Cockpit Motion Facility (CMF) motion base simulator were examined. Preliminary investigation of linear models based upon hardware data were examined to ensure that the most accurate models are used. This research identified both system improvements in the bandwidth and more reliable linear models. Advancements in the compensator design were developed and verified through multiple techniques. The position error rate feedback, the acceleration feedback and the force feedback were all analyzed in the heave direction using the nonlinear model of the hardware. Improvements were made using the position error rate feedback technique. The acceleration feedback compensator also provided noteworthy improvement, while attempts at implementing a force feedback compensator proved unsuccessful.

Challenge of emerging technologies: balancing the needs of law enforcement against the duty to protect individual rights

NASA Astrophysics Data System (ADS)

Lingerfelt, James A.

1997-01-01

This paper discusses three emerging technologies which will revolutionize the business operations of law enforcement: databases and search engines; biometric identification systems; and electronic surveillance and tracking devices. Unfortunately, these technologies may also lead to a serious ethical conflict for law enforcement. The tools will make it easier than ever to accomplish the core business of policing: crime prevention; investigation; and intelligence gathering. The same tools, used improperly, will also lead to routine intrusions on personal privacy. These technologies have been and are being developed for the private sector, the military and the intelligence community. The vendors are now aggressively marketing them to law enforcement and criminal justice agencies. The law enforcement community has embraced the technology, but without considering the long term impact. In the past, the police have abused wiretaps and other early surveillance technology. As a result, a sinister perception about police surveillance practices persists and a cumbersome bureaucracy has been imposed to control their use. Developing and establishing policies governing the use of emerging technologies can prevent these mistakes from being repeated. This paper recommends that criminal justice practitioners begin a discussion now, in advance of these technologies becoming commercially available, with a view to defining clear guidelines for their proper use.

Flutter suppression digital control law design and testing for the AFW wind tunnel model

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

1994-01-01

The design of a control law for simultaneously suppressing the symmetric and antisymmetric flutter modes of a sting mounted fixed-in-roll aeroelastic wind-tunnel model is described. The flutter suppression control law was designed using linear quadratic Gaussian theory, and it also involved control law order reduction, a gain root-locus study, and use of previous experimental results. A 23 percent increase in the open-loop flutter dynamic pressure was demonstrated during the wind-tunnel test. Rapid roll maneuvers at 11 percent above the symmetric flutter boundary were also performed when the model was in a free-to-roll configuration.

Flutter suppression digital control law design and testing for the AFW wind tunnel model

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

1992-01-01

Design of a control law for simultaneously suppressing the symmetric and antisymmetric flutter modes of a sting mounted fixed-in-roll aeroelastic wind tunnel model is described. The flutter suppression control law was designed using linear quadratic Gaussian theory, and involved control law order reduction, a gain root-locus study and use of previous experimental results. A 23 percent increase in the open-loop flutter dynamic pressure was demonstrated during the wind tunnel test. Rapid roll maneuvers at 11 percent above the symmetric flutter boundary were also performed when the model was in a free-to-roll configuration.

Flutter suppression digital control law design and testing for the AFW wind-tunnel model

NASA Technical Reports Server (NTRS)

Mukhopadhyay, Vivek

1992-01-01

Design of a control law for simultaneously suppressing the symmetric and antisymmetric flutter modes of a string mounted fixed-in-roll aeroelastic wind tunnel model is described. The flutter suppression control law was designed using linear quadratic Gaussian theory and involved control law order reduction, a gain root-locus study, and the use of previous experimental results. A 23 percent increase in open-loop flutter dynamic pressure was demonstrated during the wind tunnel test. Rapid roll maneuvers at 11 percent above the symmetric flutter boundary were also performed when the model was in a free-to-roll configuration.

Flight test trajectory control analysis

NASA Technical Reports Server (NTRS)

Walker, R.; Gupta, N.

1983-01-01

Recent extensions to optimal control theory applied to meaningful linear models with sufficiently flexible software tools provide powerful techniques for designing flight test trajectory controllers (FTTCs). This report describes the principal steps for systematic development of flight trajectory controllers, which can be summarized as planning, modeling, designing, and validating a trajectory controller. The techniques have been kept as general as possible and should apply to a wide range of problems where quantities must be computed and displayed to a pilot to improve pilot effectiveness and to reduce workload and fatigue. To illustrate the approach, a detailed trajectory guidance law is developed and demonstrated for the F-15 aircraft flying the zoom-and-pushover maneuver.

Experimental investigation of elastic mode control on a model of a transport aircraft

NASA Technical Reports Server (NTRS)

Abramovitz, M.; Heimbaugh, R. M.; Nomura, J. K.; Pearson, R. M.; Shirley, W. A.; Stringham, R. H.; Tescher, E. L.; Zoock, I. E.

1981-01-01

A 4.5 percent DC-10 derivative flexible model with active controls is fabricated, developed, and tested to investigate the ability to suppress flutter and reduce gust loads with active controlled surfaces. The model is analyzed and tested in both semispan and complete model configuration. Analytical methods are refined and control laws are developed and successfully tested on both versions of the model. A 15 to 25 percent increase in flutter speed due to the active system is demonstrated. The capability of an active control system to significantly reduce wing bending moments due to turbulence is demonstrated. Good correlation is obtained between test and analytical prediction.

Software Considerations for Subscale Flight Testing of Experimental Control Laws

NASA Technical Reports Server (NTRS)

Murch, Austin M.; Cox, David E.; Cunningham, Kevin

2009-01-01

The NASA AirSTAR system has been designed to address the challenges associated with safe and efficient subscale flight testing of research control laws in adverse flight conditions. In this paper, software elements of this system are described, with an emphasis on components which allow for rapid prototyping and deployment of aircraft control laws. Through model-based design and automatic coding a common code-base is used for desktop analysis, piloted simulation and real-time flight control. The flight control system provides the ability to rapidly integrate and test multiple research control laws and to emulate component or sensor failures. Integrated integrity monitoring systems provide aircraft structural load protection, isolate the system from control algorithm failures, and monitor the health of telemetry streams. Finally, issues associated with software configuration management and code modularity are briefly discussed.

Attitude control with realization of linear error dynamics

NASA Technical Reports Server (NTRS)

Paielli, Russell A.; Bach, Ralph E.

1993-01-01

An attitude control law is derived to realize linear unforced error dynamics with the attitude error defined in terms of rotation group algebra (rather than vector algebra). Euler parameters are used in the rotational dynamics model because they are globally nonsingular, but only the minimal three Euler parameters are used in the error dynamics model because they have no nonlinear mathematical constraints to prevent the realization of linear error dynamics. The control law is singular only when the attitude error angle is exactly pi rad about any eigenaxis, and a simple intuitive modification at the singularity allows the control law to be used globally. The forced error dynamics are nonlinear but stable. Numerical simulation tests show that the control law performs robustly for both initial attitude acquisition and attitude control.

Mathematical model of whole-process calculation for bottom-blowing copper smelting

NASA Astrophysics Data System (ADS)

Li, Ming-zhou; Zhou, Jie-min; Tong, Chang-ren; Zhang, Wen-hai; Li, He-song

2017-11-01

The distribution law of materials in smelting products is key to cost accounting and contaminant control. Regardless, the distribution law is difficult to determine quickly and accurately by mere sampling and analysis. Mathematical models for material and heat balance in bottom-blowing smelting, converting, anode furnace refining, and electrolytic refining were established based on the principles of material (element) conservation, energy conservation, and control index constraint in copper bottom-blowing smelting. Simulation of the entire process of bottom-blowing copper smelting was established using a self-developed MetCal software platform. A whole-process simulation for an enterprise in China was then conducted. Results indicated that the quantity and composition information of unknown materials, as well as heat balance information, can be quickly calculated using the model. Comparison of production data revealed that the model can basically reflect the distribution law of the materials in bottom-blowing copper smelting. This finding provides theoretical guidance for mastering the performance of the entire process.

NASA to Test In-Flight Folding Spanwise Adaptive Wing to Enhance Aircraft Efficiency

NASA Image and Video Library

2014-10-21

The objectives of testing on PTERA include the development of tools and vetting of system integration, evaluation of vehicle control law, and analysis of SAW airworthiness to examine benefits to in-flight efficiency.

Bed Bug Laws and Regulations

EPA Pesticide Factsheets

21 states have some level of regulation with regard to bed bugs. Most of these requirements focus on hotels and landlords or other property managers. The Department of Housing and Urban Development has guidance on controlling bed bugs in public housing.

An Analysis of Viable Financial Negotiations Processes and Related Internal Controls for Procurement in Pakistan

DTIC Science & Technology

2016-06-01

regulations are in accordance with UNCITRAL Model Law and are based on principles of “ accountability , transparency, fairness, efficiency and value for... account certain factors about the firm(s) for pre-qualification. These factors include past performance and experience; financial health; managerial...internal control components, along with associated principles , were discussed in detail to develop a suitable internal control system for the financial

Active Aeroelastic Wing Aerodynamic Model Development and Validation for a Modified F/A-18A Airplane

NASA Technical Reports Server (NTRS)

Cumming, Stephen B.; Diebler, Corey G.

2005-01-01

A new aerodynamic model has been developed and validated for a modified F/A-18A airplane used for the Active Aeroelastic Wing (AAW) research program. The goal of the program was to demonstrate the advantages of using the inherent flexibility of an aircraft to enhance its performance. The research airplane was an F/A-18A with wings modified to reduce stiffness and a new control system to increase control authority. There have been two flight phases. Data gathered from the first flight phase were used to create the new aerodynamic model. A maximum-likelihood output-error parameter estimation technique was used to obtain stability and control derivatives. The derivatives were incorporated into the National Aeronautics and Space Administration F-18 simulation, validated, and used to develop new AAW control laws. The second phase of flights was used to evaluate the handling qualities of the AAW airplane and the control law design process, and to further test the accuracy of the new model. The flight test envelope covered Mach numbers between 0.85 and 1.30 and dynamic pressures from 600 to 1250 pound-force per square foot. The results presented in this report demonstrate that a thorough parameter identification analysis can be used to improve upon models that were developed using other means. This report describes the parameter estimation technique used, details the validation techniques, discusses differences between previously existing F/A-18 models, and presents results from the second phase of research flights.

Lyapunov function-based control laws for revolute robot arms - Tracking control, robustness, and adaptive control

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz-Delgado, Kenneth; Bayard, David S.

1992-01-01

A new class of joint level control laws for all-revolute robot arms is introduced. The analysis is similar to a recently proposed energy-like Liapunov function approach, except that the closed-loop potential function is shaped in accordance with the underlying joint space topology. This approach gives way to a much simpler analysis and leads to a new class of control designs which guarantee both global asymptotic stability and local exponential stability. When Coulomb and viscous friction and parameter uncertainty are present as model perturbations, a sliding mode-like modification of the control law results in a robustness-enhancing outer loop. Adaptive control is formulated within the same framework. A linear-in-the-parameters formulation is adopted and globally asymptotically stable adaptive control laws are derived by simply replacing unknown model parameters by their estimates (i.e., certainty equivalence adaptation).

Modeling fast and slow earthquakes at various scales

PubMed Central

IDE, Satoshi

2014-01-01

Earthquake sources represent dynamic rupture within rocky materials at depth and often can be modeled as propagating shear slip controlled by friction laws. These laws provide boundary conditions on fault planes embedded in elastic media. Recent developments in observation networks, laboratory experiments, and methods of data analysis have expanded our knowledge of the physics of earthquakes. Newly discovered slow earthquakes are qualitatively different phenomena from ordinary fast earthquakes and provide independent information on slow deformation at depth. Many numerical simulations have been carried out to model both fast and slow earthquakes, but problems remain, especially with scaling laws. Some mechanisms are required to explain the power-law nature of earthquake rupture and the lack of characteristic length. Conceptual models that include a hierarchical structure over a wide range of scales would be helpful for characterizing diverse behavior in different seismic regions and for improving probabilistic forecasts of earthquakes. PMID:25311138

Modeling fast and slow earthquakes at various scales.

PubMed

Ide, Satoshi

2014-01-01

Earthquake sources represent dynamic rupture within rocky materials at depth and often can be modeled as propagating shear slip controlled by friction laws. These laws provide boundary conditions on fault planes embedded in elastic media. Recent developments in observation networks, laboratory experiments, and methods of data analysis have expanded our knowledge of the physics of earthquakes. Newly discovered slow earthquakes are qualitatively different phenomena from ordinary fast earthquakes and provide independent information on slow deformation at depth. Many numerical simulations have been carried out to model both fast and slow earthquakes, but problems remain, especially with scaling laws. Some mechanisms are required to explain the power-law nature of earthquake rupture and the lack of characteristic length. Conceptual models that include a hierarchical structure over a wide range of scales would be helpful for characterizing diverse behavior in different seismic regions and for improving probabilistic forecasts of earthquakes.

TCBMs over the military use of outer space

NASA Astrophysics Data System (ADS)

Takaya-Umehara, Yuri

2010-11-01

Although no legal instrument resulted from long negotiations in the UN and Conference on Disarmament (CD), the application of confidence-building measures (CBMs) that was once considered in the 1990's attracted attention again to restrict military use of outer space. Since 2005, the concept of "Transparency and confidence-building measures (TCBMs)" entered into the lexicon of space law to explore the possibility of reinforcing security in outer space activities. While CBMs have been developed and applied to treaty-based verification mechanisms, the introduction of TCBMs in space law needs further examination to fit in the context of space security. Therefore, by evaluating the function of CBMs applied to the existing law on disarmament and arms control, the author examines the application of TCBMs to space law and calls for the need to establish non-treaty-based monitoring mechanisms for transparency and confidence-building in outer space activities.

Multirate Flutter Suppression System Design for the Benchmark Active Controls Technology Wing. Part 2; Methodology Application Software Toolbox

NASA Technical Reports Server (NTRS)

Mason, Gregory S.; Berg, Martin C.; Mukhopadhyay, Vivek

2002-01-01

To study the effectiveness of various control system design methodologies, the NASA Langley Research Center initiated the Benchmark Active Controls Project. In this project, the various methodologies were applied to design a flutter suppression system for the Benchmark Active Controls Technology (BACT) Wing. This report describes the user's manual and software toolbox developed at the University of Washington to design a multirate flutter suppression control law for the BACT wing.

Candidate proof mass actuator control laws for the vibration suppression of a frame

NASA Technical Reports Server (NTRS)

Umland, Jeffrey W.; Inman, Daniel J.

1991-01-01

The vibration of an experimental flexible space truss is controlled with internal control forces produced by several proof mass actuators. Four candidate control law strategies are evaluated in terms of performance and robustness. These control laws are experimentally implemented on a quasi free-free planar truss. Sensor and actuator dynamics are included in the model such that the final closed loop is self-equilibrated. The first two control laws considered are based on direct output feedback and consist of tuning the actuator feedback gains to the lowest mode intended to receive damping. The first method feeds back only the position and velocity of the proof mass relative to the structure; this results in a traditional vibration absorber. The second method includes the same feedback paths as the first plus feedback of the local structural velocity. The third law is designed with robust H infinity control theory. The fourth strategy is an active implementation of a viscous damper, where the actuator is configured to provide a bending moment at two points on the structure. The vibration control system is then evaluated in terms of how it would benefit the space structure's position control system.

An analytic-numerical method for the construction of the reference law of operation for a class of mechanical controlled systems

NASA Astrophysics Data System (ADS)

Mizhidon, A. D.; Mizhidon, K. A.

2017-04-01

An analytic-numerical method for the construction of a reference law of operation for a class of dynamic systems describing vibrations in controlled mechanical systems is proposed. By the reference law of operation of a system, we mean a law of the system motion that satisfies all the requirements for the quality and design features of the system under permanent external disturbances. As disturbances, we consider polyharmonic functions with known amplitudes and frequencies of the harmonics but unknown initial phases. For constructing the reference law of motion, an auxiliary optimal control problem is solved in which the cost function depends on a weighting coefficient. The choice of the weighting coefficient ensures the design of the reference law. Theoretical foundations of the proposed method are given.

Dynamics and Control of Flexible Space Vehicles

NASA Technical Reports Server (NTRS)

Likins, P. W.

1970-01-01

The purpose of this report is twofold: (1) to survey the established analytic procedures for the simulation of controlled flexible space vehicles, and (2) to develop in detail methods that employ a combination of discrete and distributed ("modal") coordinates, i.e., the hybrid-coordinate methods. Analytic procedures are described in three categories: (1) discrete-coordinate methods, (2) hybrid-coordinate methods, and (3) vehicle normal-coordinate methods. Each of these approaches is described and analyzed for its advantages and disadvantages, and each is found to have an area of applicability. The hybrid-coordinate method combines the efficiency of the vehicle normal-coordinate method with the versatility of the discrete-coordinate method, and appears to have the widest range of practical application. The results in this report have practical utility in two areas: (1) complex digital computer simulation of flexible space vehicles of arbitrary configuration subject to realistic control laws, and (2) preliminary control system design based on transfer functions for linearized models of dynamics and control laws.

Dual-spin attitude control for outer planet missions

NASA Technical Reports Server (NTRS)

Ward, R. S.; Tauke, G. J.

1977-01-01

The applicability of dual-spin technology to a Jupiter orbiter with probe mission was investigated. Basic mission and system level attitude control requirements were established and preliminary mechanization and control concepts developed. A comprehensive 18-degree-of-freedom digital simulation was utilized extensively to establish control laws, study dynamic interactions, and determined key sensitivities. Fundamental system/subsystem constraints were identified, and the applicability of dual-spin technology to a Jupiter orbiter with probe mission was validated.

Air-Sea Interaction

NASA Astrophysics Data System (ADS)

Csanady, G. T.

2001-03-01

In recent years air-sea interaction has emerged as a subject in its own right, encompassing small-scale and large-scale processes in both air and sea. Air-Sea Interaction: Laws and Mechanisms is a comprehensive account of how the atmosphere and the ocean interact to control the global climate, what physical laws govern this interaction, and its prominent mechanisms. The topics covered range from evaporation in the oceans, to hurricanes, and on to poleward heat transport by the oceans. By developing the subject from basic physical (thermodynamic) principles, the book is accessible to graduate students and research scientists in meteorology, oceanography, and environmental engineering. It will also be of interest to the broader physics community involved in the treatment of transfer laws, and thermodynamics of the atmosphere and ocean.

System identification for modeling for control of flexible structures

NASA Technical Reports Server (NTRS)

Mettler, Edward; Milman, Mark

1986-01-01

The major components of a design and operational flight strategy for flexible structure control systems are presented. In this strategy an initial distributed parameter control design is developed and implemented from available ground test data and on-orbit identification using sophisticated modeling and synthesis techniques. The reliability of this high performance controller is directly linked to the accuracy of the parameters on which the design is based. Because uncertainties inevitably grow without system monitoring, maintaining the control system requires an active on-line system identification function to supply parameter updates and covariance information. Control laws can then be modified to improve performance when the error envelopes are decreased. In terms of system safety and stability the covariance information is of equal importance as the parameter values themselves. If the on-line system ID function detects an increase in parameter error covariances, then corresponding adjustments must be made in the control laws to increase robustness. If the error covariances exceed some threshold, an autonomous calibration sequence could be initiated to restore the error enveloped to an acceptable level.

Switching sliding mode force tracking control of piezoelectric-hydraulic pump-based friction element actuation systems for automotive transmissions

NASA Astrophysics Data System (ADS)

Kim, Gi-Woo; Wang, K. W.

2009-08-01

In this study, a nonlinear sliding-mode controller is designed for force tracking of a piezoelectric-hydraulic pump (PHP)-based actuation system, which is developed to replace the current electro-hydraulic actuation systems for automatic transmission (AT) friction elements, such as band brakes or clutches. By utilizing the PHP, one can eliminate the various hydraulic components (oil pump, regulating valve and control valve) in current ATs and achieve a simpler configuration with more efficient operation. With the derived governing equation of motion of the PHP-based actuation system integrated with the friction element (band brake), a switching control law is synthesized based on the sliding-mode theory. To evaluate the effectiveness of the proposed control law, its force tracking performance for the engagement of a friction element during an AT 1\\to 2 up-shift is examined experimentally. It is shown that one can successfully track the desired force trajectory for AT shift control with small tracking error. This study demonstrates the potential of the PHP as a new controllable actuation system for AT friction elements.

New multirate sampled-data control law structure and synthesis algorithm

NASA Technical Reports Server (NTRS)

Berg, Martin C.; Mason, Gregory S.; Yang, Gen-Sheng

1992-01-01

A new multirate sampled-data control law structure is defined and a new parameter-optimization-based synthesis algorithm for that structure is introduced. The synthesis algorithm can be applied to multirate, multiple-input/multiple-output, sampled-data control laws having a prescribed dynamic order and structure, and a priori specified sampling/update rates for all sensors, processor states, and control inputs. The synthesis algorithm is applied to design two-input, two-output tip position controllers of various dynamic orders for a sixth-order, two-link robot arm model.

Collision avoidance system cost-benefit analysis : volume I - technical manual

DOT National Transportation Integrated Search

1981-09-01

Collision-avoidance systems under development in the U.S.A., Japan and Germany were evaluated. The performance evaluation showed that the signal processing and the control law of a system were the key parameters that decided the system's capability, ...

Prescribed-performance fault-tolerant control for feedback linearisable systems with an aircraft application

NASA Astrophysics Data System (ADS)

Gao, Gang; Wang, Jinzhi; Wang, Xianghua

2017-05-01

This paper investigates fault-tolerant control (FTC) for feedback linearisable systems (FLSs) and its application to an aircraft. To ensure desired transient and steady-state behaviours of the tracking error under actuator faults, the dynamic effect caused by the actuator failures on the error dynamics of a transformed model is analysed, and three control strategies are designed. The first FTC strategy is proposed as a robust controller, which relies on the explicit information about several parameters of the actuator faults. To eliminate the need for these parameters and the input chattering phenomenon, the robust control law is later combined with the adaptive technique to generate the adaptive FTC law. Next, the adaptive control law is further improved to achieve the prescribed performance under more severe input disturbance. Finally, the proposed control laws are applied to an air-breathing hypersonic vehicle (AHV) subject to actuator failures, which confirms the effectiveness of the proposed strategies.

Current Performance Characteristics of NASA Langley Research Center's Cockpit Motion Base and Standardized Test Procedure for Future Performance Characterization

NASA Technical Reports Server (NTRS)

Cowen, Brandon; Stringer, Mary T.; Hutchinson, Brian K.; Davidson, Paul C.; Gupton, Lawrence E.

2014-01-01

This report documents the updated performance characteristics of NASA Langley Research Center's (LaRC) Cockpit Motion Base (CMB) after recent revisions that were made to its inner-loop, feedback control law. The modifications to the control law will be briefly described. The performance of the Cockpit Motion Facility (CMF) will be presented. A short graphical comparison to the previous control law can be found in the appendix of this report. The revised controller will be shown to yield reduced parasitic accelerations with respect to the previous controller. Metrics based on the AGARD Advisory Report No. 144 are used to assess the overall system performance due to its recent control algorithm modification. This report also documents the standardized simulator test procedure which can be used in the future to evaluate potential updates to the control law.

Law-Related Education: Trends and Development.

ERIC Educational Resources Information Center

Miller, Rosemary V.; Darnley, Susan M.

The report analyzes law-related education programs and materials developed during the period 1968-78. Specifically, it examines program motivations, assumptions, project development, and the relationship of law-related education to civic education. Law-related education is seen to include the study of the role of law in society, the legal…

Steering law for parallel mounted double-gimbaled control moment gyros

NASA Technical Reports Server (NTRS)

Kennel, H. F.

1975-01-01

Parallel mounting of double-gimbaled control moment gyros (DG CMG) is discussed in terms of simplification of the steering law. The steering law/parallel mounted DG CMG is considered to be a 'CMG kit' applicable to any space vehicle where the need for DG CMG's has been established.

The Preventive Effect of Strict Gun Control Laws on Suicide and Homicide.

ERIC Educational Resources Information Center

Lester, David; Murrell, Mary E.

1982-01-01

Examined state gun control laws and used a multidimensional scaling technique to study the relationship of strictness and death rates. Results showed states with stricter laws had lower suicide rates by firearms but higher rates by other means. No effect on homicide was found. (JAC)

Wisconsin's Drug Laws and Enforcement. Staff Brief 89-1.

ERIC Educational Resources Information Center

Matthias, Mary

This document provides information on current Wisconsin statutes and state-level activities relating to the enforcement of controlled substances laws, including assistance provided to local law enforcement agencies. Part I of this document describes the Uniform Controlled Substances Act as enacted by Wisconsin, other statutes which may be used to…

Social Change and Criminal Law

ERIC Educational Resources Information Center

Jeffery, C. Ray

1970-01-01

The impact of urbanization on criminal law and the extension of law into the area of morality (value systems) are discussed in terms of social control via punishment and deterrence. The impact of the social sciences (psychotherapy, sociology, behavioral science) is covered in terms of social control via rehabilitation and environmental…

Implementation of the DAST ARW II control laws using an 8086 microprocessor and an 8087 floating-point coprocessor. [drones for aeroelasticity research

NASA Technical Reports Server (NTRS)

Kelly, G. L.; Berthold, G.; Abbott, L.

1982-01-01

A 5 MHZ single-board microprocessor system which incorporates an 8086 CPU and an 8087 Numeric Data Processor is used to implement the control laws for the NASA Drones for Aerodynamic and Structural Testing, Aeroelastic Research Wing II. The control laws program was executed in 7.02 msec, with initialization consuming 2.65 msec and the control law loop 4.38 msec. The software emulator execution times for these two tasks were 36.67 and 61.18, respectively, for a total of 97.68 msec. The space, weight and cost reductions achieved in the present, aircraft control application of this combination of a 16-bit microprocessor with an 80-bit floating point coprocessor may be obtainable in other real time control applications.

Characteristics of Control Laws Tested on the Semi-Span Super-Sonic Transport (S4T) Wind-Tunnel Model

NASA Technical Reports Server (NTRS)

Christhilf, David M.; Moulin, Boris; Ritz, Erich; Chen, P. C.; Roughen, Kevin M.; Perry, Boyd

2012-01-01

The Semi-Span Supersonic Transport (S4T) is an aeroelastically scaled wind-tunnel model built to test active controls concepts for large flexible supersonic aircraft in the transonic flight regime. It is one of several models constructed in the 1990's as part of the High Speed Research (HSR) Program. Control laws were developed for the S4T by M4 Engineering, Inc. and by Zona Technologies, Inc. under NASA Research Announcement (NRA) contracts. The model was tested in the NASA-Langley Transonic Dynamics Tunnel (TDT) four times from 2007 to 2010. The first two tests were primarily for plant identification. The third entry was used for testing control laws for Ride Quality Enhancement, Gust Load Alleviation, and Flutter Suppression. Whereas the third entry only tested FS subcritically, the fourth test demonstrated closed-loop operation above the open-loop flutter boundary. The results of the third entry are reported elsewhere. This paper reports on flutter suppression results from the fourth wind-tunnel test. Flutter suppression is seen as a way to provide stability margins while flying at transonic flight conditions without penalizing the primary supersonic cruise design condition. An account is given for how Controller Performance Evaluation (CPE) singular value plots were interpreted with regard to progressing open- or closed-loop to higher dynamic pressures during testing.

Ethical, Legal, and Practical Issues in the Control and Regulation of Suicide Promotion and Assistance over the Internet

ERIC Educational Resources Information Center

Mishara, Brian L.; Weisstub, David N.

2007-01-01

The promotion of suicide and description of suicide methods on the Internet have led to widespread concern that legal control is mandated. Apart from value concerns pertaining to attitudes about suicide, the guarantee of freedom of expression presents a serious challenge to the introduction of restrictive laws. Recent developments in Australia and…

Time optimal control of a jet engine using a quasi-Hermite interpolation model. M.S. Thesis

NASA Technical Reports Server (NTRS)

Comiskey, J. G.

1979-01-01

This work made preliminary efforts to generate nonlinear numerical models of a two-spooled turbofan jet engine, and subject these models to a known method of generating global, nonlinear, time optimal control laws. The models were derived numerically, directly from empirical data, as a first step in developing an automatic modelling procedure.

Advances in adaptive control theory: Gradient- and derivative-free approaches

NASA Astrophysics Data System (ADS)

Yucelen, Tansel

In this dissertation, we present new approaches to improve standard designs in adaptive control theory, and novel adaptive control architectures. We first present a novel Kalman filter based approach for approximately enforcing a linear constraint in standard adaptive control design. One application is that this leads to alternative forms for well known modification terms such as e-modification. In addition, it leads to smaller tracking errors without incurring significant oscillations in the system response and without requiring high modification gain. We derive alternative forms of e- and adaptive loop recovery (ALR-) modifications. Next, we show how to use Kalman filter optimization to derive a novel adaptation law. This results in an optimization-based time-varying adaptation gain that reduces the need for adaptation gain tuning. A second major contribution of this dissertation is the development of a novel derivative-free, delayed weight update law for adaptive control. The assumption of constant unknown ideal weights is relaxed to the existence of time-varying weights, such that fast and possibly discontinuous variation in weights are allowed. This approach is particulary advantageous for applications to systems that can undergo a sudden change in dynamics, such as might be due to reconfiguration, deployment of a payload, docking, or structural damage, and for rejection of external disturbance processes. As a third and final contribution, we develop a novel approach for extending all the methods developed in this dissertation to the case of output feedback. The approach is developed only for the case of derivative-free adaptive control, and the extension of the other approaches developed previously for the state feedback case to output feedback is left as a future research topic. The proposed approaches of this dissertation are illustrated in both simulation and flight test.

Boundary Control of Linear Uncertain 1-D Parabolic PDE Using Approximate Dynamic Programming.

PubMed

Talaei, Behzad; Jagannathan, Sarangapani; Singler, John

2018-04-01

This paper develops a near optimal boundary control method for distributed parameter systems governed by uncertain linear 1-D parabolic partial differential equations (PDE) by using approximate dynamic programming. A quadratic surface integral is proposed to express the optimal cost functional for the infinite-dimensional state space. Accordingly, the Hamilton-Jacobi-Bellman (HJB) equation is formulated in the infinite-dimensional domain without using any model reduction. Subsequently, a neural network identifier is developed to estimate the unknown spatially varying coefficient in PDE dynamics. Novel tuning law is proposed to guarantee the boundedness of identifier approximation error in the PDE domain. A radial basis network (RBN) is subsequently proposed to generate an approximate solution for the optimal surface kernel function online. The tuning law for near optimal RBN weights is created, such that the HJB equation error is minimized while the dynamics are identified and closed-loop system remains stable. Ultimate boundedness (UB) of the closed-loop system is verified by using the Lyapunov theory. The performance of the proposed controller is successfully confirmed by simulation on an unstable diffusion-reaction process.

WHEN TOBACCO TARGETS DIRECT DEMOCRACY

PubMed Central

Laposata, Elizabeth; Kennedy, Allison P.

2013-01-01

Tobacco control advocates began to use ballot initiatives to enact tobacco control policies in the late 1970s. In response, the tobacco industry worked for over two decades to change laws governing initiative and referendum processes to prevent passage of tobacco control measures. In 1981, the tobacco industry’s political lobbying arm, the Tobacco Institute, created a front group that presented itself as a neutral initiative research clearinghouse to affect changes in state initiative and referenda laws. In 1990, the Tobacco Institute began creating an in-house team, and worked with third party groups to try to change state initiative laws. While the industry ultimately abandoned both efforts when neither achieved immediate success, over time, the industry’s goals have penetrated legitimate discourse on the I&R process in the United States and many specific ideas it advocated have garnered mainstream support. Direct democracy advocates, as well as public health advocates and policymakers, need to understand the tobacco industry’s goals (which other industries adopted) of limiting the direct democracy process in order to ensure that any changes do not inadvertently increase the power of the special interests that direct democracy was developed to counterbalance. PMID:24603083

Spacecraft nonlinear control

NASA Technical Reports Server (NTRS)

Sheen, Jyh-Jong; Bishop, Robert H.

1992-01-01

The feedback linearization technique is applied to the problem of spacecraft attitude control and momentum management with control moment gyros (CMGs). The feedback linearization consists of a coordinate transformation, which transforms the system to a companion form, and a nonlinear feedback control law to cancel the nonlinear dynamics resulting in a linear equivalent model. Pole placement techniques are then used to place the closed-loop poles. The coordinate transformation proposed here evolves from three output functions of relative degree four, three, and two, respectively. The nonlinear feedback control law is presented. Stability in a neighborhood of a controllable torque equilibrium attitude (TEA) is guaranteed and this fact is demonstrated by the simulation results. An investigation of the nonlinear control law shows that singularities exist in the state space outside the neighborhood of the controllable TEA. The nonlinear control law is simplified by a standard linearization technique and it is shown that the linearized nonlinear controller provides a natural way to select control gains for the multiple-input, multiple-output system. Simulation results using the linearized nonlinear controller show good performance relative to the nonlinear controller in the neighborhood of the TEA.

Noise Protection

NASA Technical Reports Server (NTRS)

1980-01-01

Environmental Health Systems puts forth an increasing effort in the U.S. to develop ways of controlling noise, particularly in industrial environments due to Federal and State laws, labor union insistence and new findings relative to noise pollution impact on human health. NASA's Apollo guidance control system aided in the development of a noise protection product, SMART. The basis of all SMART products is SMART compound a liquid plastic mixture with exceptional energy/sound absorbing qualities. The basic compound was later refined for noise protection use.

TRAP abortion laws and partisan political party control of state government.

PubMed

Medoff, Marshall H; Dennis, Christopher

2011-01-01

Targeted Regulation of Abortion Providers (or TRAP) laws impose medically unnecessary and burdensome regulations solely on abortion providers in order to make abortion services more expensive and difficult to obtain. Using event history analysis, this article examines the determinants of the enactment of a TRAP law by states over the period 1974–2008. The empirical results find that Republican institutional control of a state's legislative/executive branches is positively associated with a state enacting a TRAP law, while Democratic institutional control is negatively associated with a state enacting a TRAP law. The percentage of a state's population that is Catholic, public anti-abortion attitudes, state political ideology, and the abortion rate in a state are statistically insignificant predictors of a state enacting a TRAP law. The empirical results are consistent with the hypothesis that abortion is a redistributive issue and not a morality issue.

Determining the Requisite Components of Visual Threat Detection to Improve Operational Performance

DTIC Science & Technology

2014-04-01

cognitive processes, and may be enhanced by focusing training development on the principle components such as causal reasoning. The second report will...discuss the development and evaluation of a research-based training exemplar. Visual threat detection pervades many military contexts, but is also... developing computer-controlled exercises to study the primary components of visual threat detection. Similarly, civilian law enforcement officers were

Genetic Algorithm Optimizes Q-LAW Control Parameters

NASA Technical Reports Server (NTRS)

Lee, Seungwon; von Allmen, Paul; Petropoulos, Anastassios; Terrile, Richard

2008-01-01

A document discusses a multi-objective, genetic algorithm designed to optimize Lyapunov feedback control law (Q-law) parameters in order to efficiently find Pareto-optimal solutions for low-thrust trajectories for electronic propulsion systems. These would be propellant-optimal solutions for a given flight time, or flight time optimal solutions for a given propellant requirement. The approximate solutions are used as good initial solutions for high-fidelity optimization tools. When the good initial solutions are used, the high-fidelity optimization tools quickly converge to a locally optimal solution near the initial solution. Q-law control parameters are represented as real-valued genes in the genetic algorithm. The performances of the Q-law control parameters are evaluated in the multi-objective space (flight time vs. propellant mass) and sorted by the non-dominated sorting method that assigns a better fitness value to the solutions that are dominated by a fewer number of other solutions. With the ranking result, the genetic algorithm encourages the solutions with higher fitness values to participate in the reproduction process, improving the solutions in the evolution process. The population of solutions converges to the Pareto front that is permitted within the Q-law control parameter space.

A comprehensive examination of the influence of state tobacco control programs and policies on youth smoking.

PubMed

Farrelly, Matthew C; Loomis, Brett R; Han, Beth; Gfroerer, Joe; Kuiper, Nicole; Couzens, G Lance; Dube, Shanta; Caraballo, Ralph S

2013-03-01

We examined the influence of tobacco control policies (tobacco control program expenditures, smoke-free air laws, youth access law compliance, and cigarette prices) on youth smoking outcomes (smoking susceptibility, past-year initiation, current smoking, and established smoking). We combined data from the 2002 to 2008 National Surveys on Drug Use and Health with state and municipality population data from the US Census Bureau to assess the associations between state tobacco control policy variables and youth smoking outcomes, focusing on youths aged 12 to 17 years. We also examined the influence of policy variables on youth access when these variables were held at 2002 levels. Per capita funding for state tobacco control programs was negatively associated with all 4 smoking outcomes. Smoke-free air laws were negatively associated with all outcomes except past-year initiation, and cigarette prices were associated only with current smoking. We found no association between these outcomes and retailer compliance with youth access laws. Smoke-free air laws and state tobacco control programs are effective strategies for curbing youth smoking.

A Comprehensive Examination of the Influence of State Tobacco Control Programs and Policies on Youth Smoking

PubMed Central

Loomis, Brett R.; Han, Beth; Gfroerer, Joe; Kuiper, Nicole; Couzens, G. Lance; Dube, Shanta; Caraballo, Ralph S.

2013-01-01

Objectives. We examined the influence of tobacco control policies (tobacco control program expenditures, smoke-free air laws, youth access law compliance, and cigarette prices) on youth smoking outcomes (smoking susceptibility, past-year initiation, current smoking, and established smoking). Methods. We combined data from the 2002 to 2008 National Surveys on Drug Use and Health with state and municipality population data from the US Census Bureau to assess the associations between state tobacco control policy variables and youth smoking outcomes, focusing on youths aged 12 to 17 years. We also examined the influence of policy variables on youth access when these variables were held at 2002 levels. Results. Per capita funding for state tobacco control programs was negatively associated with all 4 smoking outcomes. Smoke-free air laws were negatively associated with all outcomes except past-year initiation, and cigarette prices were associated only with current smoking. We found no association between these outcomes and retailer compliance with youth access laws. Conclusions. Smoke-free air laws and state tobacco control programs are effective strategies for curbing youth smoking. PMID:23327252

Development of a Novel, Two-Processor Architecture for a Small UAV Autopilot System,

DTIC Science & Technology

2006-07-26

is, and the control laws the user implements to control it. The flight control system board will contain the processor selected for this system...Unit (IMU). The IMU contains solid-state gyros and accelerometers and uses these to determine the attitude of the UAV within the three dimensions of...multiple-UAV swarming for combat support operations. The mission processor board will contain the processor selected to execute the mission

Fractional-order active fault-tolerant force-position controller design for the legged robots using saturated actuator with unknown bias and gain degradation

NASA Astrophysics Data System (ADS)

Farid, Yousef; Majd, Vahid Johari; Ehsani-Seresht, Abbas

2018-05-01

In this paper, a novel fault accommodation strategy is proposed for the legged robots subject to the actuator faults including actuation bias and effective gain degradation as well as the actuator saturation. First, the combined dynamics of two coupled subsystems consisting of the dynamics of the legs subsystem and the body subsystem are developed. Then, the interaction of the robot with the environment is formulated as the contact force optimization problem with equality and inequality constraints. The desired force is obtained by a dynamic model. A robust super twisting fault estimator is proposed to precisely estimate the defective torque amplitude of the faulty actuator in finite time. Defining a novel fractional sliding surface, a fractional nonsingular terminal sliding mode control law is developed. Moreover, by introducing a suitable auxiliary system and using its state vector in the designed controller, the proposed fault-tolerant control (FTC) scheme guarantees the finite-time stability of the closed-loop control system. The robustness and finite-time convergence of the proposed control law is established using the Lyapunov stability theory. Finally, numerical simulations are performed on a quadruped robot to demonstrate the stable walking of the robot with and without actuator faults, and actuator saturation constraints, and the results are compared to results with an integer order fault-tolerant controller.

Stability analysis of multiple-robot control systems

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz, Kenneth

1989-01-01

In a space telerobotic service scenario, cooperative motion and force control of multiple robot arms are of fundamental importance. Three paradigms to study this problem are proposed. They are distinguished by the set of variables used for control design. They are joint torques, arm tip force vectors, and an accelerated generalized coordinate set. Control issues related to each case are discussed. The latter two choices require complete model information, which presents practical modeling, computational, and robustness problems. Therefore, focus is on the joint torque control case to develop relatively model independent motion and internal force control laws. The rigid body assumption allows the motion and force control problems to be independently addressed. By using an energy motivated Lyapunov function, a simple proportional derivative plus gravity compensation type of motion control law is always shown to be stabilizing. The asymptotic convergence of the tracing error to zero requires the use of a generalized coordinate with the contact constraints taken into account. If a non-generalized coordinate is used, only convergence to a steady state manifold can be concluded. For the force control, both feedforward and feedback schemes are analyzed. The feedback control, if proper care has been taken, exhibits better robustness and transient performance.

Tactical medical skill requirements for law enforcement officers: a 10-year analysis of line-of-duty deaths.

PubMed

Sztajnkrycer, Matthew D

2010-01-01

In the absence of other data, military Tactical Combat Casualty Care (TCCC) precepts are increasingly being adapted to law enforcement needs. The purpose of this study is to better describe the nature of potentially preventable law enforcement Line-of-Duty Deaths (LODDs) occurring as a result of felonious assaults. A retrospective analysis was performed of open source data available through the US Federal Bureau of Investigation Uniform Crime Reporting (UCR) Law Enforcement Officers Killed and Assaulted (LEOKA) program for the years 1998-2007 inclusive. After applying exclusion criteria, 341 victim officers were included in the study. The most common cause of death was head trauma (n=198), followed by chest trauma (n=90). There were 123 victim officers that suffered potentially preventable deaths; the majority of these injuries involved the chest. Over the 10-year study period, only two officers (0.6%) died from isolated extremity hemorrhage. The current emphasis of TCCC on control of exsanguinating extremity hemorrhage may not meet the needs of law enforcement personnel in an environment with expedited access to well-developed trauma systems. Further study is needed to better examine the causes of preventable deaths in law enforcement officers, as well as the most appropriate law enforcement tactical medical skill set and treatment priorities.

Modelling and control of a rotor supported by magnetic bearings

NASA Technical Reports Server (NTRS)

Gurumoorthy, R.; Pradeep, A. K.

1994-01-01

In this paper we develop a dynamical model of a rotor and the active magnetic bearings used to support the rotor. We use this model to develop a stable state feedback control of the magnetic bearing system. We present the development of a rigid body model of the rotor, utilizing both Rotation Matrices (Euler Angles) and Euler Parameters (Quaternions). In the latter half of the paper we develop a stable state feedback control of the actively controlled magnetic bearing to control the rotor position under inbalances. The control law developed takes into account the variation of the model with rotational speed. We show stability over the whole operating range of speeds for the magnetic bearing system. Simulation results are presented to demonstrate the closed loop system performance. We develop the model of the magnetic bearing, and present two schemes for the excitation of the poles of the actively controlled magnetic bearing. We also present a scheme for averaging multiple sensor measurements and splitting the actuation forces amongst redundant actuators.

Applied adaptive disturbance rejection using output redefinition on magnetic bearings

NASA Astrophysics Data System (ADS)

Matras, Alex Logan

Recent work has shown Adaptive Disturbance Rejection to be an effective technique for rejecting forces due to imbalance, runout and base motion disturbances on flywheels supported by magnetic bearings over a large span of frequencies. Often the applicability of some of the adaptive methods is limited because they require certain properties (such as almost-strict positive realness) that magnetic bearings do not possess. In this thesis, one method for adaptive disturbance rejection, called Adaptive Feedforward Cancellation (AFC), is modified to allow for a much wider range of frequencies to be rejected. This is accomplished by redefining the output of the original system to be the output from a reduced order state estimator instead. This can give a new system with an infinite gain margin. Additionally, the adaptation laws for the two disturbance rejection gains are slightly modified so that each adapts to a different signal in order to provide the best performance. A detailed model of a magnetic bearing is developed and computer simulations based on that model are performed to give an initial test of the new control law. A state-of-the-art magnetic bearing setup is then developed and used to implement the new control laws and determine their effectiveness. The results are successful and validate the new ideas that are presented.

Five years after the Hawai'i smoke-free law: tourism and hospitality economic indicators appear unharmed.

PubMed

Dobson Amato, Katharine A; Rivard, Cheryl; Lipsher, Julian; Hyland, Andrew

2013-10-01

Opponents of Hawai'i's smoke-free law argued that such a law would lead to a decrease in tourism. The purpose of this study is to determine if there is evidence of an adverse impact of Hawai'i's smoke-free law on tourism utilizing data obtained from Hawai'i's Department of Business, Economic Development & Tourism website for tourists from the United States. Descriptive statistics were reported before and after the law and linear regression was used to assess the relationship between the implementation of the law and changes in indicators of tourism while adjusting for underlying economic factors. The most pronounced fluctuations observed with all tourism indicators occurred around the time the US entered the recession (December 2007), with steady increases following the end of the US recession. While controlling for economic and seasonal trends, the presence of the smoke-free law was associated with an increase in arrivals (β= 42847.9; 95% CI: 16303.3, 69392.5), accommodation employees (β= 969.0; 95% CI: 351.1, 1586.8) and food services & beverage places employees (β=3390.8; 95% CI: 2326.9, 4454.7). Fluctuations in tourism indicators are likely to be associated with greater economic forces, such as decreasing GDP and consumer confidence in the United States and greater global economic trends, rather than the smoke-free law.

Five Years After the Hawai‘i Smoke-free Law: Tourism and Hospitality Economic Indicators Appear Unharmed

PubMed Central

Rivard, Cheryl; Lipsher, Julian; Hyland, Andrew

2013-01-01

Opponents of Hawai‘i's smoke-free law argued that such a law would lead to a decrease in tourism. The purpose of this study is to determine if there is evidence of an adverse impact of Hawai‘i's smoke-free law on tourism utilizing data obtained from Hawai‘i's Department of Business, Economic Development & Tourism website for tourists from the United States. Descriptive statistics were reported before and after the law and linear regression was used to assess the relationship between the implementation of the law and changes in indicators of tourism while adjusting for underlying economic factors. The most pronounced fluctuations observed with all tourism indicators occurred around the time the US entered the recession (December 2007), with steady increases following the end of the US recession. While controlling for economic and seasonal trends, the presence of the smoke-free law was associated with an increase in arrivals (β= 42847.9; 95% CI: 16303.3, 69392.5), accommodation employees (β= 969.0; 95% CI: 351.1, 1586.8) and food services & beverage places employees (β=3390.8; 95% CI: 2326.9, 4454.7). Fluctuations in tourism indicators are likely to be associated with greater economic forces, such as decreasing GDP and consumer confidence in the United States and greater global economic trends, rather than the smoke-free law. PMID:24167770

Hubble Space Telescope Fine Guidance Sensor and Two-Gyro Control Law Design, Implementation, and On-Orbit Performance. Part 3

NASA Technical Reports Server (NTRS)

Clapp, Brian R.

2005-01-01

For fifteen years, the science mission of the Hubble Space Telescope (HST) required using at least three rate gyros for n Controlling with alternate sensors to replace failing gyros can extend the HST science mission. A two-gyro control law has been designed and implemented using magnetometers, star trackers, and Fine Guidance Sensors (FGSs) to control vehicle rate about the missing gyro axis. The three aforementioned sensors are used in succession to reduce HST boresight jitter to less than 7 milli-arcseconds rms prior to science imaging. The Magnetometer and 2-Gyro (M2G) control law is used for large angle maneuvers and attitude control during earth. occultation of star trackers and FGSs. The Tracker and 2-Gyro (T2G) control law dampens M2G rates and controls attitude in preparation for guide star acquisition with the FGSs. The Fine Guidance Sensor and 2-Gyro (F2G) control law dampens T2G rates and controls HST attitude during science imaging. This paper describes the F2G control law. Details of F2G algorithms are presented, including computation of the FGS-measured star vector using non-linear equations, optimal estimation of HST body rate, design of the F2G control laws and gyro bias observer, SISO and MIMO linear stability analyses, and design of the F2G intramode transition and guide star acquisition logic. Results from an FGS flight spare ground test are presented that define acceptable HST jitter levels for successful guide star acquisition under two-gyro control. HST-specific disturbance and noise models are described that are based upon flight telemetry; these models are used in HSTSIM, a high-fidelity non-linear time domain simulation, to predict HST on-orbit disturbance responses and FGS interferometer Loss of Lock (LOL) characteristics under F2G control. Additional HSTSIM results are presented predicting HST quiescent boresight jitter performance, science maneuver performance, and observer configuration performance during F2G operation. Simulation results are compared to on-orbit data b m F2G flight tests performed in February 2005. Science images and point spread functions from the Advanced Camera for Surveys (ACS) High Resolution Camera (HRC) are presented that compare HST science performance under F2G versus three-gyro control. Images and flight telemetry show that HST boresight jitter with the new F2G control law is usually less than jitter using the three-gyro law, and HST boresight jitter during F2G operation is dependent upon guide star magnitude.

Litigation in Argentina: challenging the tobacco industry

PubMed Central

Flores, M L; Barnoya, J; Mejia, R; Alderete, E; Pérez‐Stable, E J

2006-01-01

Objective To evaluate the processes and outcomes of tobacco litigation in Argentina and to analyse the strategies of the tobacco industry to oppose litigation using tobacco industry documents. Methods A systematic search of tobacco industry documents on the internet dating from 1978 to 2002. Law library searches using Argentinean official and unofficial reports systems were combined with computerised online searches. Results There have been at least 15 failed litigation cases in Argentina and the tobacco industry presented a concerted defence in every claim regardless of cost. We categorised 11 cases as product liability and nicotine addiction, two as health care reimbursement, and two as criminal law and secondhand smoke. Industry strategies included hiring legal consultants from prestigious international and Argentinean law firms and developing litigation prevention programmes. Industry monitored legal academic meetings, controlled the development of new product liability legislation, obtained favourable opinions from experts, and closely observed the development of litigation in Argentina. Conclusion The strategies used by the industry have been successful in preventing recovery for tobacco injuries through litigation. Argentinean health advocates and lawyers need to be aware of the roles and strategies of the tobacco industry in order to develop effective litigation in Argentina. PMID:16565455

Litigation in Argentina: challenging the tobacco industry.

PubMed

Flores, M L; Barnoya, J; Mejia, R; Alderete, E; Pérez-Stable, E J

2006-04-01

To evaluate the processes and outcomes of tobacco litigation in Argentina and to analyse the strategies of the tobacco industry to oppose litigation using tobacco industry documents. A systematic search of tobacco industry documents on the internet dating from 1978 to 2002. Law library searches using Argentinean official and unofficial reports systems were combined with computerised online searches. There have been at least 15 failed litigation cases in Argentina and the tobacco industry presented a concerted defence in every claim regardless of cost. We categorised 11 cases as product liability and nicotine addiction, two as health care reimbursement, and two as criminal law and secondhand smoke. Industry strategies included hiring legal consultants from prestigious international and Argentinean law firms and developing litigation prevention programmes. Industry monitored legal academic meetings, controlled the development of new product liability legislation, obtained favourable opinions from experts, and closely observed the development of litigation in Argentina. The strategies used by the industry have been successful in preventing recovery for tobacco injuries through litigation. Argentinean health advocates and lawyers need to be aware of the roles and strategies of the tobacco industry in order to develop effective litigation in Argentina.

Nonlinear adaptive control of an elastic robotic arm

NASA Technical Reports Server (NTRS)

Singh, S. N.

1986-01-01

An approach to control of a class of nonlinear flexible robotic systems is presented. For simplicity, a robot arm (PUMA-type) with three rotational joints is considered. The third link is assumed to be elastic. An adaptive torquer control law is derived for controlling the joint angles. This controller includes a dynamic system in the feedback path, requires only joint angle and rate for feedback, and asymptotically decomposes the elastic dynamics into two subsystems representing the transverse vibrations of the elastic link in two orthogonal planes. To damp out the elastic vibration, a force control law using modal feedback is synthesized. The combination of the torque and force control laws accomplishes joint angle control and elastic mode stabilization.

Collision avoidance system cost-benefit analysis : volume III - appendices F-M

DOT National Transportation Integrated Search

1981-09-01

Collision-avoidance systems under development in the U.S.A., Japan and Germany were evaluated. The performance evaluation showed that the signal processing and the control law of a system were the key parameters that decided the system's capability, ...

Collision avoidance system cost-benefit analysis : volume II - appendices A-E

DOT National Transportation Integrated Search

1981-09-01

Collision-avoidance systems under development in the U.S.A., Japan and Germany were evaluated. The performance evaluation showed that the signal processing and the control law of a system were the key parameters that decided the system's capability, ...

Laws of the United States Relating to Water Pollution Control and Environmental Quality.

ERIC Educational Resources Information Center

Congress of the U.S., Washington, DC. House Committee on Public Works.

This compilation of Federal legislation contains copies of twelve Public Laws, four Executive Orders, and five International Conventions relevant to water pollution control. It also contains two Public Laws and two Executive Orders pertaining to environmental quality. There is a brief introduction summarizing the provisions of each Act. (AL)

Nonlinear control systems - A brief overview of historical and recent advances

NASA Astrophysics Data System (ADS)

Iqbal, Jamshed; Ullah, Mukhtar; Khan, Said Ghani; Khelifa, Baizid; Ćuković, Saša

2017-12-01

Last five decades witnessed remarkable developments in linear control systems and thus problems in this subject has been largely resolved. The scope of the present paper is beyond linear solutions. Modern technology demands sophisticated control laws to meet stringent design specifications thus highlighting the increasingly conspicuous position of nonlinear control systems, which is the topic of this paper. Historical role of analytical concepts in analysis and design of nonlinear control systems is briefly outlined. Recent advancements in these systems from applications perspective are examined with critical comments on associated challenges. It is anticipated that wider dissemination of this comprehensive review will stimulate more collaborations among the research community and contribute to further developments.

Development of the HIDEC inlet integration mode. [Highly Integrated Digital Electronic Control

NASA Technical Reports Server (NTRS)

Chisholm, J. D.; Nobbs, S. G.; Stewart, J. F.

1990-01-01

The Highly Integrated Digital Electronic Control (HIDEC) development program conducted at NASA-Ames/Dryden will use an F-15 test aircraft for flight demonstration. An account is presently given of the HIDEC Inlet Integration mode's design concept, control law, and test aircraft implementation, with a view to its performance benefits. The enhancement of performance is a function of the use of Digital Electronic Engine Control corrected engine airflow computations to improve the scheduling of inlet ramp positions in real time; excess thrust can thereby be increased by 13 percent at Mach 2.3 and 40,000 ft. Aircraft supportability is also improved through the obviation of inlet controllers.

Optimal Control Modification for Robust Adaptation of Singularly Perturbed Systems with Slow Actuators

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.; Ishihara, Abraham; Stepanyan, Vahram; Boskovic, Jovan

2009-01-01

Recently a new optimal control modification has been introduced that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. This modification is based on an optimal control formulation to minimize the L2 norm of the tracking error. The optimal control modification adaptive law results in a stable adaptation in the presence of a large adaptive gain. This study examines the optimal control modification adaptive law in the context of a system with a time scale separation resulting from a fast plant with a slow actuator. A singular perturbation analysis is performed to derive a modification to the adaptive law by transforming the original system into a reduced-order system in slow time. The model matching conditions in the transformed time coordinate results in increase in the feedback gain and modification of the adaptive law.

Optimal Control Modification Adaptive Law for Time-Scale Separated Systems

NASA Technical Reports Server (NTRS)

Nguyen, Nhan T.

2010-01-01

Recently a new optimal control modification has been introduced that can achieve robust adaptation with a large adaptive gain without incurring high-frequency oscillations as with the standard model-reference adaptive control. This modification is based on an optimal control formulation to minimize the L2 norm of the tracking error. The optimal control modification adaptive law results in a stable adaptation in the presence of a large adaptive gain. This study examines the optimal control modification adaptive law in the context of a system with a time scale separation resulting from a fast plant with a slow actuator. A singular perturbation analysis is performed to derive a modification to the adaptive law by transforming the original system into a reduced-order system in slow time. A model matching conditions in the transformed time coordinate results in an increase in the actuator command that effectively compensate for the slow actuator dynamics. Simulations demonstrate effectiveness of the method.

Systematic methods for the design of a class of fuzzy logic controllers

NASA Astrophysics Data System (ADS)

Yasin, Saad Yaser

2002-09-01

Fuzzy logic control, a relatively new branch of control, can be used effectively whenever conventional control techniques become inapplicable or impractical. Various attempts have been made to create a generalized fuzzy control system and to formulate an analytically based fuzzy control law. In this study, two methods, the left and right parameterization method and the normalized spline-base membership function method, were utilized for formulating analytical fuzzy control laws in important practical control applications. The first model was used to design an idle speed controller, while the second was used to control an inverted control problem. The results of both showed that a fuzzy logic control system based on the developed models could be used effectively to control highly nonlinear and complex systems. This study also investigated the application of fuzzy control in areas not fully utilizing fuzzy logic control. Three important practical applications pertaining to the automotive industries were studied. The first automotive-related application was the idle speed of spark ignition engines, using two fuzzy control methods: (1) left and right parameterization, and (2) fuzzy clustering techniques and experimental data. The simulation and experimental results showed that a conventional controller-like performance fuzzy controller could be designed based only on experimental data and intuitive knowledge of the system. In the second application, the automotive cruise control problem, a fuzzy control model was developed using parameters adaptive Proportional plus Integral plus Derivative (PID)-type fuzzy logic controller. Results were comparable to those using linearized conventional PID and linear quadratic regulator (LQR) controllers and, in certain cases and conditions, the developed controller outperformed the conventional PID and LQR controllers. The third application involved the air/fuel ratio control problem, using fuzzy clustering techniques, experimental data, and a conversion algorithm, to develop a fuzzy-based control algorithm. Results were similar to those obtained by recently published conventional control based studies. The influence of the fuzzy inference operators and parameters on performance and stability of the fuzzy logic controller was studied Results indicated that, the selections of certain parameters or combinations of parameters, affect greatly the performance and stability of the fuzzy controller. Diagnostic guidelines used to tune or change certain factors or parameters to improve controller performance were developed based on knowledge gained from conventional control methods and knowledge gained from the experimental and the simulation results of this study.

Fault-tolerant cooperative output regulation for multi-vehicle systems with sensor faults

NASA Astrophysics Data System (ADS)

Qin, Liguo; He, Xiao; Zhou, D. H.

2017-10-01

This paper presents a unified framework of fault diagnosis and fault-tolerant cooperative output regulation (FTCOR) for a linear discrete-time multi-vehicle system with sensor faults. The FTCOR control law is designed through three steps. A cooperative output regulation (COR) controller is designed based on the internal mode principle when there are no sensor faults. A sufficient condition on the existence of the COR controller is given based on the discrete-time algebraic Riccati equation (DARE). Then, a decentralised fault diagnosis scheme is designed to cope with sensor faults occurring in followers. A residual generator is developed to detect sensor faults of each follower, and a bank of fault-matching estimators are proposed to isolate and estimate sensor faults of each follower. Unlike the current distributed fault diagnosis for multi-vehicle systems, the presented decentralised fault diagnosis scheme in each vehicle reduces the communication and computation load by only using the information of the vehicle. By combing the sensor fault estimation and the COR control law, an FTCOR controller is proposed. Finally, the simulation results demonstrate the effectiveness of the FTCOR controller.

Scale-Free Brain-Wave Music from Simultaneously EEG and fMRI Recordings

PubMed Central

Lu, Jing; Wu, Dan; Yang, Hua; Luo, Cheng; Li, Chaoyi; Yao, Dezhong

2012-01-01

In the past years, a few methods have been developed to translate human EEG to music. In 2009, PloS One 4 e5915, we developed a method to generate scale-free brainwave music where the amplitude of EEG was translated to music pitch according to the power law followed by both of them, the period of an EEG waveform is translated directly to the duration of a note, and the logarithm of the average power change of EEG is translated to music intensity according to the Fechner's law. In this work, we proposed to adopt simultaneously-recorded fMRI signal to control the intensity of the EEG music, thus an EEG-fMRI music is generated by combining two different and simultaneous brain signals. And most importantly, this approach further realized power law for music intensity as fMRI signal follows it. Thus the EEG-fMRI music makes a step ahead in reflecting the physiological process of the scale-free brain. PMID:23166768

Elements of Pacific public health laws: an analysis of the public health acts of Papua New Guinea, Vanuatu, the Solomon Islands, and Fiji.

PubMed

Howse, Genevieve

2012-09-01

Pacific countries are sovereign nations with distinctive histories, ethnicity, customs, primary resources, economies, and health systems. Despite these and other acknowledged differences, similarities exist in many areas such as geography, legal history, and culture. Many share the experience of colonization, with imported British laws and the subsequent experience of independence. Most Pacific countries are also developing countries. This article broadly describes approaches to legislating in public health in Papua New Guinea, Fiji, Vanuatu, and the Solomon Islands and notes common elements in their public health laws, in particular, in relation to administration, allocation of powers and responsibilities, interaction with local government, communicable disease control, and nuisance. The article concludes that many Pacific public health laws could deliver better support for current health policy, more sensitivity to the culture and customs of the region, and better management of public health risk through laws that are better suited to their Pacific environment, easier to understand, more flexible, and more relevant to current health policy.

Constrained model predictive control, state estimation and coordination

NASA Astrophysics Data System (ADS)

Yan, Jun

In this dissertation, we study the interaction between the control performance and the quality of the state estimation in a constrained Model Predictive Control (MPC) framework for systems with stochastic disturbances. This consists of three parts: (i) the development of a constrained MPC formulation that adapts to the quality of the state estimation via constraints; (ii) the application of such a control law in a multi-vehicle formation coordinated control problem in which each vehicle operates subject to a no-collision constraint posed by others' imperfect prediction computed from finite bit-rate, communicated data; (iii) the design of the predictors and the communication resource assignment problem that satisfy the performance requirement from Part (ii). Model Predictive Control (MPC) is of interest because it is one of the few control design methods which preserves standard design variables and yet handles constraints. MPC is normally posed as a full-state feedback control and is implemented in a certainty-equivalence fashion with best estimates of the states being used in place of the exact state. However, if the state constraints were handled in the same certainty-equivalence fashion, the resulting control law could drive the real state to violate the constraints frequently. Part (i) focuses on exploring the inclusion of state estimates into the constraints. It does this by applying constrained MPC to a system with stochastic disturbances. The stochastic nature of the problem requires re-posing the constraints in a probabilistic form. In Part (ii), we consider applying constrained MPC as a local control law in a coordinated control problem of a group of distributed autonomous systems. Interactions between the systems are captured via constraints. First, we inspect the application of constrained MPC to a completely deterministic case. Formation stability theorems are derived for the subsystems and conditions on the local constraint set are derived in order to guarantee local stability or convergence to a target state. If these conditions are met for all subsystems, then this stability is inherited by the overall system. For the case when each subsystem suffers from disturbances in the dynamics, own self-measurement noises, and quantization errors on neighbors' information due to the finite-bit-rate channels, the constrained MPC strategy developed in Part (i) is appropriate to apply. In Part (iii), we discuss the local predictor design and bandwidth assignment problem in a coordinated vehicle formation context. The MPC controller used in Part (ii) relates the formation control performance and the information quality in the way that large standoff implies conservative performance. We first develop an LMI (Linear Matrix Inequality) formulation for cross-estimator design in a simple two-vehicle scenario with non-standard information: one vehicle does not have access to the other's exact control value applied at each sampling time, but to its known, pre-computed, coupling linear feedback control law. Then a similar LMI problem is formulated for the bandwidth assignment problem that minimizes the total number of bits by adjusting the prediction gain matrices and the number of bits assigned to each variable. (Abstract shortened by UMI.)

Active vibration control with model correction on a flexible laboratory grid structure

NASA Technical Reports Server (NTRS)

Schamel, George C., II; Haftka, Raphael T.

1991-01-01

This paper presents experimental and computational comparisons of three active damping control laws applied to a complex laboratory structure. Two reduced structural models were used with one model being corrected on the basis of measured mode shapes and frequencies. Three control laws were investigated, a time-invariant linear quadratic regulator with state estimation and two direct rate feedback control laws. Experimental results for all designs were obtained with digital implementation. It was found that model correction improved the agreement between analytical and experimental results. The best agreement was obtained with the simplest direct rate feedback control.

24 CFR 570.601 - Public Law 88-352 and Public Law 90-284; affirmatively furthering fair housing; Executive Order...

Code of Federal Regulations, 2010 CFR

2010-04-01

... Urban Development Regulations Relating to Housing and Urban Development (Continued) OFFICE OF ASSISTANT SECRETARY FOR COMMUNITY PLANNING AND DEVELOPMENT, DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT COMMUNITY... 24 Housing and Urban Development 3 2010-04-01 2010-04-01 false Public Law 88-352 and Public Law 90...

32 CFR 701.110 - Conditions of disclosure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... jurisdiction within or under the control of the U.S. for a civil or criminal law enforcement activity provided the civil or criminal law enforcement activity is authorized by law; the head of the law enforcement... enforcement purpose (such as criminal investigations, enforcement of a civil law, or a similar purpose) for...

32 CFR 701.110 - Conditions of disclosure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... jurisdiction within or under the control of the U.S. for a civil or criminal law enforcement activity provided the civil or criminal law enforcement activity is authorized by law; the head of the law enforcement... enforcement purpose (such as criminal investigations, enforcement of a civil law, or a similar purpose) for...

L(sub 1) Adaptive Control Design for NASA AirSTAR Flight Test Vehicle

NASA Technical Reports Server (NTRS)

Gregory, Irene M.; Cao, Chengyu; Hovakimyan, Naira; Zou, Xiaotian

2009-01-01

In this paper we present a new L(sub 1) adaptive control architecture that directly compensates for matched as well as unmatched system uncertainty. To evaluate the L(sub 1) adaptive controller, we take advantage of the flexible research environment with rapid prototyping and testing of control laws in the Airborne Subscale Transport Aircraft Research system at the NASA Langley Research Center. We apply the L(sub 1) adaptive control laws to the subscale turbine powered Generic Transport Model. The presented results are from a full nonlinear simulation of the Generic Transport Model and some preliminary pilot evaluations of the L(sub 1) adaptive control law.

New class of control laws for robotic manipulators. I - Nonadaptive case. II - Adaptive case

NASA Technical Reports Server (NTRS)

Wen, John T.; Bayard, David S.

1988-01-01

A new class of exponentially stabilizing control laws for joint level control of robot arms is discussed. Closed-loop exponential stability has been demonstrated for both the set point and tracking control problems by a slight modification of the energy Lyapunov function and the use of a lemma which handles third-order terms in the Lyapunov function derivatives. In the second part, these control laws are adapted in a simple fashion to achieve asymptotically stable adaptive control. The analysis addresses the nonlinear dynamics directly without approximation, linearization, or ad hoc assumptions, and uses a parameterization based on physical (time-invariant) quantities.

Politics of corporate social control: the federal response to industrial water pollution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yeager, P.C.

1981-01-01

In the annals of criminology and the sociology of law, the phenomenon of corporate illegalities has been seriously neglected. Moreover, the relatively few social scientific studies of illegal corporate behavior have often approached the subject from limited theoretical perspectives. These studies have generally overlooked a critical element in criminological understanding; the role of law and its administration in generating violation rates that may be said to be characteristic of the prevailing social structure. This dissertation develops an integrated theoretical approach to a type of corporate illegality, environmental pollution. In this approach, law is seen as integral to the understanding ofmore » crime, and both are situated within the broad socio-economic structure of the United States in the latter half of the 20th century. This research first reviews and analyzes the history of the federal government's efforts to control industrial water pollution, seeking to identify the social structural limits on regulatory activity. Statistical analyses of data on the federal processing of industrial pollution violations are then presented, with a view toward analyzing the correlates of both business behavior and the federal response. The analyses test a proposed model of industrial regulation, and provide important support for the perspective linking law and crime.« less

Two different approaches for a control law of single gimbal control moment gyros

NASA Technical Reports Server (NTRS)

Schiehlen, W. O.

1972-01-01

In the field of momentum exchange attitude control systems, single gimbal control moment gyros (SGCMG) are of increasing interest. A gimbal angle approach and a gimbal rate approach are presented for the SGCMG control law including the singularity avoidance. Both approaches are compared and some illustrative examples are given.

How do international trade obligations affect policy options for obesity prevention? Lessons from recent developments in trade and tobacco control.

PubMed

von Tigerstrom, Barbara

2013-06-01

Regulatory measures, including taxes and subsidies on food and beverage products, food labelling requirements, regulation of food content and regulation of food marketing, have been proposed to encourage healthier eating and prevent obesity. The objective of this article is to explore the extent to which international trade agreements affect governments' choices to use such regulatory measures. It reviews key provisions of relevant World Trade Organization (WTO) agreements and their implications. Some insights can be gained by examining 2 recent developments in the WTO regarding tobacco control: a current dispute involving Australia's plain packaging law and its effect on trademarks, and a recent decision involving the United States law banning flavoured cigarettes. This decision said that the ban did not restrict trade more than necessary to fulfil its legitimate health objective, but it was discriminatory because it banned imported products (clove cigarettes) while exempting domestic products (menthol cigarettes) with similar characteristics. The conclusion we can draw from this decision is that WTO member states probably enjoy a significant degree of latitude in developing food regulations as part of an obesity prevention strategy, so long as those do not disproportionately affect imported products and therefore raise questions of discrimination. The approach taken in this case encourages the adoption of public health policies that are consistent with strong scientific evidence, but may restrict governments' ability to make political compromises, which could frustrate some proposals. The ongoing development of WTO law will continue to affect policy choices in public health. Copyright © 2013 Canadian Diabetes Association. Published by Elsevier Inc. All rights reserved.

Evaluation of the use of Global Youth Tobacco Survey (GYTS) data for developing evidence-based tobacco control policies in Turkey.

PubMed

Erguder, Toker; Cakir, Banu; Aslan, Dilek; Warren, Charles W; Jones, Nathan R; Asma, Samira

2008-12-15

The tobacco control effort in Turkey has made significant progress in recent years. Turkey initiated its tobacco control effort with the passing of Law 4207 (The Prevention of Harmful Effects of Tobacco Products) in 1996 and ratified the World Health Organization (WHO) Framework Convention on Tobacco Control (FCTC) in 2004. It is important to base policy decisions on valid and reliable evidence from population-based, representative studies that are periodically repeated to enable policy makers to monitor the results of their interventions and to appropriately tailor anti-tobacco activities towards future needs. The Global Youth Tobacco Survey (GYTS) was developed to track tobacco use among young people and enhance the capacity of countries to design, implement, and evaluate tobacco control and prevention programs. Turkey conducted the GYTS in 2003 and data from this survey can be used as baseline measures for evaluation of the tobacco control programs implemented by the Ministry of Health (MOH) of the Turkish government. The GYTS was conducted in 2003 on a representative sample of students aged 13 to 15 years. It indicated that almost 3 in 10 students in Turkey had ever smoked cigarettes, with significantly higher rates among boys. Current cigarette smoking rates were lower, at 9% for boys and 4% for girls. The prevalence of current use of other tobacco products was about half these figures for each gender. About 80% were exposed to secondhand smoke. Exposure to pro-smoking media messages was not rare. Almost half of the smokers 'usually' bought their tobacco from a store, despite the law prohibiting this. Exposure to teaching against smoking in schools was not universal. Findings from the GYTS, with periodic repeats of the survey, can be used to monitor the impact of enforcing various provisions of the present law (No: 4207), the progress made in achieving the goals of the WHO FCTC, and the effectiveness of various preventive interventions against smoking. Such data would inform and help in the development of public health strategy.

CRIMINAL ABORTION—A Consideration of Ways to Reduce Incidence

PubMed Central

Kummer, Jerome M.; Leavy, Zad

1961-01-01

The problem of criminal abortion in the United States is of enormous magnitude, both in terms of incidence and of resultant morbidity and mortality. Several studies suggest that one of every five pregnancies terminates in criminal abortion, or a total of more than one million abortions for 1960, with a possibility of more than 5,000 deaths resulting therefrom. The inadequate laws regarding therapeutic abortion in most jurisdictions contribute much to the problem. Tracing the origins of these laws provides additional clues concerning the development of this enigma. Suggested answers to the problem include: (1) Broadening and clarifying therapeutic abortion laws to reflect current medical practice, yet provide stringent controls; (2) prevention of unwanted pregnancy through consultation centers for women, encouragement of contraceptive research and education of the public. PMID:13755105

Active flutter suppression using optical output feedback digital controllers

NASA Technical Reports Server (NTRS)

1982-01-01

A method for synthesizing digital active flutter suppression controllers using the concept of optimal output feedback is presented. A convergent algorithm is employed to determine constrained control law parameters that minimize an infinite time discrete quadratic performance index. Low order compensator dynamics are included in the control law and the compensator parameters are computed along with the output feedback gain as part of the optimization process. An input noise adjustment procedure is used to improve the stability margins of the digital active flutter controller. Sample rate variation, prefilter pole variation, control structure variation and gain scheduling are discussed. A digital control law which accommodates computation delay can stabilize the wing with reasonable rms performance and adequate stability margins.

Barcelona 2002: law, ethics, and human rights. Using the law to improve access to treatments.

PubMed

Elliott, Richard; Parmar, Sharan; Divan, Vivek; Berger, Jonathan

2002-12-01

The XIII International AIDS Conference in Durban, South Africa in July 2000 focused worldwide attention on the problem of accessing treatments in developing countries. In the interim, thanks to the work of activists - from demonstrations to court cases, and from acts of public courage by people living with HIV/AIDS to ongoing lobbying of politicians and trade negotiators - some very significant developments have occurred. But the reality is that the vast majority of people living with HIV/AIDS still lack access to affordable, quality medicines. This article, a summary of a paper presented at "Putting Third First: Vaccines, Access to Treatments and the Law," a satellite meeting held at Barcelona on 5 July 2002 and organized by the Canadian HIV/AIDS Legal Network, the AIDS Law Project, South Africa, and the Lawyers Collective HIV/AIDS Unit, India, explores three approaches for improving access. In the first part, Richard Elliott provides an overview of the state of the right to health as embodied in international human rights law; comments on the experience to date in litigating claims to the right to health; and identifies potential strategies activists can adopt to advance recognition of the right to health. In the second part, Sharan Parmar and Vivek Divan describe price-control and drug-financing mechanisms used by industrialized countries to increase the affordability of medicines; and discuss how some of these mechanisms could be adapted for use in developing countries. Finally, Jonathan Berger describes the use of litigation in the courts by the Treatment Action Campaign in South Africa.

The Legality of Nuclear Weapons Employment under the International Humanitarian Law of Coercion Control.

DTIC Science & Technology

1987-01-01

fm$0 TELMT OF NUICLEMR IdERPONiS EMPLOYMENT UNDERTH 1/ I INTERNRTIOSEL NUIfI.. (U) AIR FORCE INST OF TECH I NRIONT-PATTERSON AFI ON R R PRICE 1967...Coercion Control c. Rank: Major d. Service: United States Air Force e. Date: 1987 I . Number of pages: 106 g. Degree awarded: Master ot Laws (LL.M.) in...33 A. Sources of International Humanitarian Law ............ 33 B. Use of Coercive Force Under International Law ..... 34 C. Basis Principles

Control of a human-powered helicopter in hover

NASA Technical Reports Server (NTRS)

Totah, Joseph J.; Patterson, William

1988-01-01

The study of a control system for the Da Vinci 2 human-powered helicopter in hovering flight is documented. This helicopter has two very large, slowly rotating rotor blades and is considered to be unstable in hover. The control system is designed to introduce stability in hover by maintaining level rotors through the use of rotor tip mounted control surfaces. A five degree of freedom kinematic model was developed to study this control system and is documented. Results of this study show that the unaugmented configuration is unstable due to the large Lock Number, and the augmented configuration is stable. The role of NASA in this study included the development and analysis of the kinematic model and control laws. Both analytical and numerical techniques were used.

LMI-Based Generation of Feedback Laws for a Robust Model Predictive Control Algorithm

NASA Technical Reports Server (NTRS)

Acikmese, Behcet; Carson, John M., III

2007-01-01

This technical note provides a mathematical proof of Corollary 1 from the paper 'A Nonlinear Model Predictive Control Algorithm with Proven Robustness and Resolvability' that appeared in the 2006 Proceedings of the American Control Conference. The proof was omitted for brevity in the publication. The paper was based on algorithms developed for the FY2005 R&TD (Research and Technology Development) project for Small-body Guidance, Navigation, and Control [2].The framework established by the Corollary is for a robustly stabilizing MPC (model predictive control) algorithm for uncertain nonlinear systems that guarantees the resolvability of the associated nite-horizon optimal control problem in a receding-horizon implementation. Additional details of the framework are available in the publication.

Teleoperated position control of a PUMA robot

NASA Technical Reports Server (NTRS)

Austin, Edmund; Fong, Chung P.

1987-01-01

A laboratory distributed computer control teleoperator system is developed to support NASA's future space telerobotic operation. This teleoperator system uses a universal force-reflecting hand controller in the local iste as the operator's input device. In the remote site, a PUMA controller recieves the Cartesian position commands and implements PID control laws to position the PUMA robot. The local site uses two microprocessors while the remote site uses three. The processors communicate with each other through shared memory. The PUMA robot controller was interfaced through custom made electronics to bypass VAL. The development status of this teleoperator system is reported. The execution time of each processor is analyzed, and the overall system throughput rate is reported. Methods to improve the efficiency and performance are discussed.

The Law and Juvenile Justice for People of Color in Elementary and Secondary Schools.

ERIC Educational Resources Information Center

Brown, Frank; Russo, Charles J.; Hunter, Richard C.

2002-01-01

Recent crime control laws have negatively impacted children of color, imposing a form of social control. Increased laws and punishments have not deterred juvenile delinquents but rather increased the number of criminals. Recommends teaching children about the justice system through education on the Constitution, thus encouraging them to obey the…

Applications of active adaptive noise control to jet engines

NASA Technical Reports Server (NTRS)

Shoureshi, Rahmat; Brackney, Larry

1993-01-01

During phase 2 research on the application of active noise control to jet engines, the development of multiple-input/multiple-output (MIMO) active adaptive noise control algorithms and acoustic/controls models for turbofan engines were considered. Specific goals for this research phase included: (1) implementation of a MIMO adaptive minimum variance active noise controller; and (2) turbofan engine model development. A minimum variance control law for adaptive active noise control has been developed, simulated, and implemented for single-input/single-output (SISO) systems. Since acoustic systems tend to be distributed, multiple sensors, and actuators are more appropriate. As such, the SISO minimum variance controller was extended to the MIMO case. Simulation and experimental results are presented. A state-space model of a simplified gas turbine engine is developed using the bond graph technique. The model retains important system behavior, yet is of low enough order to be useful for controller design. Expansion of the model to include multiple stages and spools is also discussed.

Three-axis stabilization of spacecraft using parameter-independent nonlinear quaternion feedback

NASA Technical Reports Server (NTRS)

Joshi, Suresh M.; Kelkar, Atul G.

1994-01-01

This paper considers the problem of rigid spacecraft. A nonlinear control law which uses the feedback of the unit quaternion and the measured angular velocities is proposed and is shown to provide global asymptotic stability. The control law does not require the knowledge of the system parameters, and is therefore robust to modeling errors. The significance of the control law is that it can be used for large-angle maneuvers with guaranteed stability.

The role of the law in reducing tuberculosis transmission in Botswana, South Africa and Zambia

PubMed Central

Emerson, Courtney N; Lederer, Philip; Lipke, Ginny; Kapata, Nathan; Lanje, Samson; Peters, Annatjie C; Zulu, Isaac; Marston, Barbara J; Miller, Bess

2016-01-01

Abstract Objective To determine whether laws and regulations in Botswana, South Africa and Zambia – three countries with a high tuberculosis and HIV infection burden – address elements of the World Health Organization (WHO) policy on tuberculosis infection control. Methods An online desk review of laws and regulations that address six selected elements of the WHO policy on tuberculosis infection control in the three countries was conducted in November 2015 using publicly available domestic legal databases. The six elements covered: (i) national policy and legal framework; (ii) health facility design, construction and use; (iii) tuberculosis disease surveillance among health workers; (iv) patients’ and health workers’ rights; (v) monitoring of infection control measures; and (vi) relevant research. Findings The six elements were found to be adequately addressed in the three countries’ laws and regulations. In all three, tuberculosis case-reporting is required, as is tuberculosis surveillance among health workers. Each country’s legal and regulatory framework also addresses the need to respect individuals’ rights and privacy while safeguarding public health. These laws and regulations create a strong foundation for tuberculosis infection control. Although the legal and regulatory frameworks thoroughly address tuberculosis infection control, their dissemination, implementation and enforcement were not assessed, nor was their impact on public health. Conclusion Laws and regulations in Botswana, South Africa and Zambia address all six selected elements of the WHO policy on tuberculosis infection control. However, the lack of data on their implementation is a limitation. Future research should assess the implementation and public health impact of laws and regulations. PMID:27274593

Biological Movement and Laws of Physics.

PubMed

Latash, Mark L

2017-07-01

Living systems may be defined as systems able to organize new, biology-specific, laws of physics and modify their parameters for specific tasks. Examples include the force-length muscle dependence mediated by the stretch reflex, and the control of movements with modification of the spatial referent coordinates for salient performance variables. Low-dimensional sets of referent coordinates at a task level are transformed to higher-dimensional sets at lower hierarchical levels in a way that ensures stability of performance. Stability of actions can be controlled independently of the actions (e.g., anticipatory synergy adjustments). Unintentional actions reflect relaxation processes leading to drifts of corresponding referent coordinates in the absence of changes in external load. Implications of this general framework for movement disorders, motor development, motor skill acquisition, and even philosophy are discussed.

Historical Development of Media Systems. I. Japan. Communication and Society 1.

ERIC Educational Resources Information Center

Ito, Shinichi; And Others

This report presents an insight into indigenous media forms and the introduction of modern media in Japan, and follows media development through the war and occupation to the present day. The report discusses (1) the birth of the newspaper in Japan, (2) control laws and regulations, (3) press policy under the allied forces' occupation of Japan,…

On Complete Control and Synchronization of Zhang Chaotic System with Uncertain Parameters using Adaptive Control Method

NASA Astrophysics Data System (ADS)

Tirandaz, Hamed

2018-03-01

Chaos control and synchronization of chaotic systems is seemingly a challenging problem and has got a lot of attention in recent years due to its numerous applications in science and industry. This paper concentrates on the control and synchronization problem of the three-dimensional (3D) Zhang chaotic system. At first, an adaptive control law and a parameter estimation law are achieved for controlling the behavior of the Zhang chaotic system. Then, non-identical synchronization of Zhang chaotic system is provided with considering the Lü chaotic system as the follower system. The synchronization problem and parameters identification are achieved by introducing an adaptive control law and a parameters estimation law. Stability analysis of the proposed method is proved by the Lyapanov stability theorem. In addition, the convergence of the estimated parameters to their truly unknown values are evaluated. Finally, some numerical simulations are carried out to illustrate and to validate the effectiveness of the suggested method.

Comfort-oriented vehicle suspension design with skyhook inerter configuration

NASA Astrophysics Data System (ADS)

Hu, Yinlong; Chen, Michael Z. Q.; Sun, Yonghui

2017-09-01

This paper is concerned with the comfort-oriented vehicle suspension design problem by using a skyhook inerter configuration. The rationale of the skyhook inerter is to use a grounded inerter to virtually increase the sprung mass of a vehicle, as it is analytically demonstrated that increasing the sprung mass can always improve the ride comfort performance. Semi-active means to realize the skyhook inerter configuration are investigated by using semi-active inerters. Three control laws, that is the on-off control, the anti-chatter on-off control, and the continuous control, are proposed for the semi-active inerter to approximate the skyhook inerter. Numerical simulations are performed to demonstrate the effectiveness and performances of these control laws. It is shown that the semi-active realizations of the skyhook inerter by using the proposed control laws can achieve over 10% improvement compared with the traditional strut, and similar performances are obtained for these control laws, with slight differences with respect to different static stiffnesses of the suspension system.

Construction of a WMR for trajectory tracking control: experimental results.

PubMed

Silva-Ortigoza, R; Márquez-Sánchez, C; Marcelino-Aranda, M; Marciano-Melchor, M; Silva-Ortigoza, G; Bautista-Quintero, R; Ramos-Silvestre, E R; Rivera-Díaz, J C; Muñoz-Carrillo, D

2013-01-01

This paper reports a solution for trajectory tracking control of a differential drive wheeled mobile robot (WMR) based on a hierarchical approach. The general design and construction of the WMR are described. The hierarchical controller proposed has two components: a high-level control and a low-level control. The high-level control law is based on an input-output linearization scheme for the robot kinematic model, which provides the desired angular velocity profiles that the WMR has to track in order to achieve the desired position (x∗, y∗) and orientation (φ∗). Then, a low-level control law, based on a proportional integral (PI) approach, is designed to control the velocity of the WMR wheels to ensure those tracking features. Regarding the trajectories, this paper provides the solution or the following cases: (1) time-varying parametric trajectories such as straight lines and parabolas and (2) smooth curves fitted by cubic splines which are generated by the desired data points {(x₁∗, y₁∗),..., (x(n)∗, y(n)∗)}. A straightforward algorithm is developed for constructing the cubic splines. Finally, this paper includes an experimental validation of the proposed technique by employing a DS1104 dSPACE electronic board along with MATLAB/Simulink software.

Construction of a WMR for Trajectory Tracking Control: Experimental Results

PubMed Central

Silva-Ortigoza, R.; Márquez-Sánchez, C.; Marcelino-Aranda, M.; Marciano-Melchor, M.; Silva-Ortigoza, G.; Bautista-Quintero, R.; Ramos-Silvestre, E. R.; Rivera-Díaz, J. C.; Muñoz-Carrillo, D.

2013-01-01

This paper reports a solution for trajectory tracking control of a differential drive wheeled mobile robot (WMR) based on a hierarchical approach. The general design and construction of the WMR are described. The hierarchical controller proposed has two components: a high-level control and a low-level control. The high-level control law is based on an input-output linearization scheme for the robot kinematic model, which provides the desired angular velocity profiles that the WMR has to track in order to achieve the desired position (x∗, y∗) and orientation (φ∗). Then, a low-level control law, based on a proportional integral (PI) approach, is designed to control the velocity of the WMR wheels to ensure those tracking features. Regarding the trajectories, this paper provides the solution or the following cases: (1) time-varying parametric trajectories such as straight lines and parabolas and (2) smooth curves fitted by cubic splines which are generated by the desired data points {(x1∗, y1∗),..., (xn∗, yn∗)}. A straightforward algorithm is developed for constructing the cubic splines. Finally, this paper includes an experimental validation of the proposed technique by employing a DS1104 dSPACE electronic board along with MATLAB/Simulink software. PMID:23997679

Failure of enforcement controlled substance laws in health policy for prescribing opiate medications: a painful assessment of morbidity and mortality.

PubMed

Miller, Norman S

2006-01-01

Controlled substances can be used for legitimate medical purposes to relieve pain and suffering, and allow management of medical and surgical conditions, whether acute or chronic in duration. However, because these are attractive, addicting drugs, diversion from sources such as physicians and pharmacists can lead to serious health problems. Of importance is that addiction to opiate medications can interfere with treatment of the original pain condition, and can lead to life threatening states because of poor judgment and depressed mood in the users. Consequently, the public has a vested interest in protecting the medical uses of these medications on the one hand, although reducing the morbidity and mortality from their diversion and addictive use. The controlled substance laws contain 3 sources of policy framework that governs the medical use and diversion of controlled substances: (1) international treaties, (2) federal laws and regulations, and (3) state laws and regulations. These laws are aimed at balancing the need to controlling use with adverse consequences against the therapeutic benefits opiate medications provide the public.

Integrated Application of Active Controls (IAAC) technology to an advanced subsonic transport project: Current and advanced act control system definition study, volume 1

NASA Technical Reports Server (NTRS)

Hanks, G. W.; Shomber, H. A.; Dethman, H. A.; Gratzer, L. B.; Maeshiro, A.; Gangsaas, D.; Blight, J. D.; Buchan, S. M.; Crumb, C. B.; Dorwart, R. J.

1981-01-01

An active controls technology (ACT) system architecture was selected based on current technology system elements and optimal control theory was evaluated for use in analyzing and synthesizing ACT multiple control laws. The system selected employs three redundant computers to implement all of the ACT functions, four redundant smaller computers to implement the crucial pitch-augmented stability function, and a separate maintenance and display computer. The reliability objective of probability of crucial function failure of less than 1 x 10 to the -9th power per flight of 1 hr can be met with current technology system components, if the software is assumed fault free and coverage approaching 1.0 can be provided. The optimal control theory approach to ACT control law synthesis yielded comparable control law performance much more systematically and directly than the classical s-domain approach. The ACT control law performance, although somewhat degraded by the inclusion of representative nonlinearities, remained quite effective. Certain high-frequency gust-load alleviation functions may require increased surface rate capability.

Tiger beetles pursue prey using a proportional control law with a delay of one half-stride.

PubMed

Haselsteiner, Andreas F; Gilbert, Cole; Wang, Z Jane

2014-06-06

Tiger beetles are fast diurnal predators capable of chasing prey under closed-loop visual guidance. We investigated this control system using statistical analyses of high-speed digital recordings of beetles chasing a moving prey dummy in a laboratory arena. Correlation analyses reveal that the beetle uses a proportional control law in which the angular position of the prey relative to the beetle's body axis drives the beetle's angular velocity with a delay of about 28 ms. The proportionality coefficient or system gain, 12 s(-1), is just below critical damping. Pursuit simulations using the derived control law predict angular orientation during pursuits with a residual error of about 7°. This is of the same order of magnitude as the oscillation imposed by the beetle's alternating tripod gait, which was not factored into the control law. The system delay of 28 ms equals a half-stride period, i.e. the time between the touch down of alternating tripods. Based on these results, we propose a physical interpretation of the observed control law: to turn towards its prey, the beetle on average exerts a sideways force proportional to the angular position of the prey measured a half-stride earlier.

A steering law for a roof-type configuration for a single-gimbal control moment gyro system

NASA Technical Reports Server (NTRS)

Yoshikawa, T.

1974-01-01

Single-Gimbal Control Moment Gyro (SGCMG) systems have been investigated for attitude control of the Large Space Telescope (LST) and the High Energy Astronomy Observatory (HEAO). However, various proposed steering laws for the SGCMG systems thus far have some defects because of singular states of the system. In this report, a steering law for a roof-type SGCMG system is proposed which is based on a new momentum distribution scheme that makes all the singular states unstable. This momentum distribution scheme is formulated by a treatment of the system as a sampled-data system. From analytical considerations, it is shown that this steering law gives control performance which is satisfactory for practical applications. Results of the preliminary computer simulation entirely support this premise.

A real time data acquisition system using the MIL-STD-1553B bus. [for transmission of data to host computer for control law processing

NASA Technical Reports Server (NTRS)

Peri, Frank, Jr.

1992-01-01

A flight digital data acquisition system that uses the MIL-STD-1553B bus for transmission of data to a host computer for control law processing is described. The instrument, the Remote Interface Unit (RIU), can accommodate up to 16 input channels and eight output channels. The RIU employs a digital signal processor to perform local digital filtering before sending data to the host. The system allows flexible sensor and actuator data organization to facilitate quick control law computations on the host computer. The instrument can also run simple control laws autonomously without host intervention. The RIU and host computer together have replaced a similar larger, ground minicomputer system with favorable results.

Autonomous assembly with collision avoidance of a fleet of flexible spacecraft based on disturbance observer

NASA Astrophysics Data System (ADS)

Chen, Ti; Wen, Hao

2018-06-01

This paper presents a distributed control law with disturbance observer for the autonomous assembly of a fleet of flexible spacecraft to construct a large flexible space structure. The fleet of flexible spacecraft is driven to the pre-assembly configuration firstly, and then to the desired assembly configuration. A distributed assembly control law with disturbance observer is proposed by treating the flexible dynamics as disturbances acting on the rigid motion of the flexible spacecraft. Theoretical analysis shows that the control law can actuate the fleet to the desired configuration. Moreover, the collision avoidance between the members is also considered in the process from initial configuration to pre-assembly configuration. Finally, a numerical example is presented to verify the feasibility of proposed mission planning and the effectiveness of control law.

Booster seat laws and child fatalities: a case-control study.

PubMed

Farmer, P; Howard, A; Rothman, L; Macpherson, A

2009-10-01

A case-control study examined, primarily, the association between booster seat laws and fatalities among children in frontal collisions and, secondarily, the association between booster seat laws and reported restraint use, and restraint use and child fatalities. Children who died in a crash in the US were cases, and children who survived a fatal crash were controls. Subjects were child passengers (4-8 years old) in the Fatality Analysis Reporting System Database, 1995-2005. In states with a booster seat law, children were less likely to die than in states without a law (OR 0.80; 95% CI 0.66 to 0.98). They were also more likely to be restrained (adjusted OR 1.59; 95% CI 1.21 to 2.09) and were more likely to be correctly restrained (adjusted OR 4.44; 95% CI 3.18 to 6.20). It is concluded that booster seat laws are associated with a decrease in child deaths and an increase in correct restraint use among children involved in a fatal crash in the USA.

The Utility of Including the Strengths of Underage Drinking Laws in Determining Their Effect on Outcomes

PubMed Central

Fell, James C.; Scherer, Michael; Voas, Robert

2015-01-01

Background To control underage drinking in the United States, which has been associated with an estimated 5,000 deaths and 2.6 million injuries or other harm annually, each state has developed a unique set of laws. Previous research examining these laws’ effectiveness has frequently focused on the laws’ existence without considering variance in sanctions, enforcement, or exemptions. Methods We scored 20 minimum legal drinking age 21 (MLDA-21) laws for their strengths and weaknesses based on (1) sanctions for violating the law, (2) exceptions or exemptions affecting application, and (3) provisions affecting the law or enforcement. We then replicated a 2009 study of the effects of six MLDA-21 laws in three different ways (using identical structural equation modeling): Study 1—eight additional years of data, no law strengths; Study 2—years from the original study, added law strengths; Study 3—additional years, law strengths, serving as an update of the six laws’ effects. Results In all three studies—and the original study—keg registration laws were associated with both an unexpected significant increase (+11%, p < .001) in underage drinking-driver ratios and a notable 25% reduction in per capita beer consumption—opposing results that are difficult to explain. In Study 3, possession and purchase laws were associated with a significant decrease in underage drinking-driver fatal crash ratios (−4.9%, p < .001; −3.6%, p < .001, respectively). Similarly, zero tolerance and use and lose laws were associated with reductions in underage drinking-driver ratios (−2.8%, p < .001; −5.3%, p < .001, respectively). Conclusions Including strengths and weaknesses of underage drinking laws is important when examining their effects on various outcomes as the model fit statistics indicated. We suggest that this will result in more accurate and more reliable estimates of the impact of the laws on various outcome measures. PMID:26148047

Adaptive control of bivalirudin in the cardiac intensive care unit.

PubMed

Zhao, Qi; Edrich, Thomas; Paschalidis, Ioannis Ch

2015-02-01

Bivalirudin is a direct thrombin inhibitor used in the cardiac intensive care unit when heparin is contraindicated due to heparin-induced thrombocytopenia. Since it is not a commonly used drug, clinical experience with its dosing is sparse. In earlier work [1], we developed a dynamic system model that accurately predicts the effect of bivalirudin given dosage over time and patient physiological characteristics. This paper develops adaptive dosage controllers that regulate its effect to desired levels. To that end, and in the case that bivalirudin model parameters are available, we develop a Model Reference Control law. In the case that model parameters are unknown, an indirect Model Reference Adaptive Control scheme is applied to estimate model parameters first and then adapt the controller. Alternatively, direct Model Reference Adaptive Control is applied to adapt the controller directly without estimating model parameters first. Our algorithms are validated using actual patient data from a large hospital in the Boston area.

Modern Control Aspects of Automatically Steered Vehicles

DOT National Transportation Integrated Search

1971-12-01

In the study of automatically steered rubber tired vehicles, little emphasis in the past has been placed on the steering control laws. The report examines the control law problem from the state variable point of view and it is shown that, except for ...

[Knowledge and attitudes toward smoke-free law among smoking and non-smoking medical students].

PubMed

Zielińska-Danch, Wioleta; Goniewicz, Maciej Ł; Koszowski, Bartosz; Leszczyńska, Joanna; Czogała, Jan; Szołtysek-Bołdys, Izabela; Antosiewicz, Beata; Sobczak, Andrzej

2010-01-01

Tobacco smoking is common among various social groups. There is still high prevalence of smoking among health care professionals. The aim of the study was to assess knowledge about smoke-free law in public places in Poland among smoking and nonsmoking students of selected medical university. We surveyed 50 students of one medical university aged 23 +/- 2 years. Control group consisted with 61 students of other universities located in the same region aged 23 +/- 3 years. We developed a new survey to assess students knowledge about smoke-free regulations and their implementations in various public places. Smoking status was verified with exhaled carbon monoxide levels (COex). 57% off all surveyed students declared being familiar with smoke-free law. However, we detected a significant difference between the knowledge of medical vs. nonmedical students (76% vs. 41%, p < 0.05). The knowledge about smoke-free law in Poland among students is not sufficient, especially among nonmedical students.

Multi-model predictive control based on LMI: from the adaptation of the state-space model to the analytic description of the control law

NASA Astrophysics Data System (ADS)

Falugi, P.; Olaru, S.; Dumur, D.

2010-08-01

This article proposes an explicit robust predictive control solution based on linear matrix inequalities (LMIs). The considered predictive control strategy uses different local descriptions of the system dynamics and uncertainties and thus allows the handling of less conservative input constraints. The computed control law guarantees constraint satisfaction and asymptotic stability. The technique is effective for a class of nonlinear systems embedded into polytopic models. A detailed discussion of the procedures which adapt the partition of the state space is presented. For the practical implementation the construction of suitable (explicit) descriptions of the control law are described upon concrete algorithms.

Flutter suppression and gust alleviation using active controls

NASA Technical Reports Server (NTRS)

Nissim, E.

1975-01-01

Application of the aerodynamic energy approach to some problems of flutter suppression and gust alleviation were considered. A simple modification of the control-law is suggested for achieving the required pitch control in the use of a leading edge - trailing edge activated strip. The possible replacement of the leading edge - trailing edge activated strip by a trailing edge - tab strip is also considered as an alternate solution. Parameters affecting the performance of the activated leading edge - trailing edge strip were tested on the Arava STOL Transport and the Westwind Executive Jet Transport and include strip location, control-law gains and a variation in the control-law itself.

A comprehensive model to evaluate implementation of the world health organization framework convention of tobacco control

PubMed Central

Sarrafzadegan, Nizal; Kelishad, Roya; Rabiei, Katayoun; Abedi, Heidarali; Mohaseli, Khadijeh Fereydoun; Masooleh, Hasan Azaripour; Alavi, Mousa; Heidari, Gholamreza; Ghaffari, Mostafa; O’Loughlin, Jennifer

2012-01-01

Background: Iran is one of the countries that has ratified the World Health Organization Framework Convention of Tobacco Control (WHO-FCTC), and has implemented a series of tobacco control interventions including the Comprehensive Tobacco Control Law. Enforcement of this legislation and assessment of its outcome requires a dedicated evaluation system. This study aimed to develop a generic model to evaluate the implementation of the Comprehensive Tobacco Control Law in Iran that was provided based on WHO-FCTC articles. Materials and Methods: Using a grounded theory approach, qualitative data were collected from 265 subjects in individual interviews and focus group discussions with policymakers who designed the legislation, key stakeholders, and members of the target community. In addition, field observations data in supermarkets/shops, restaurants, teahouses and coffee shops were collected. Data were analyzed in two stages through conceptual theoretical coding. Findings: Overall, 617 open codes were extracted from the data into tables; 72 level-3 codes were retained from the level-2 code series. Using a Model Met paradigm, the relationships between the components of each paradigm were depicted graphically. The evaluation model entailed three levels, namely: short-term results, process evaluation and long-term results. Conclusions: Central concept of the process of evaluation is that enforcing the law influences a variety of internal and environmental factors including legislative changes. These factors will be examined during the process evaluation and context evaluation. The current model can be applicable for providing FCTC evaluation tools across other jurisdictions. PMID:23833621

International Telecommunication Control: International Law and the Ordering of Satellite and Other Forms of International Broadcasting.

ERIC Educational Resources Information Center

Smith, Delbert D.

The need for and the available alternatives for international telecommunication controls are examined, and a functional approach to this area of law is offered. Information from a number of areas is collected and examined as it relates to the basic problem. These areas include general principles of international law, the activities of the…

Prosthetic Leg Control in the Nullspace of Human Interaction.

PubMed

Gregg, Robert D; Martin, Anne E

2016-07-01

Recent work has extended the control method of virtual constraints, originally developed for autonomous walking robots, to powered prosthetic legs for lower-limb amputees. Virtual constraints define desired joint patterns as functions of a mechanical phasing variable, which are typically enforced by torque control laws that linearize the output dynamics associated with the virtual constraints. However, the output dynamics of a powered prosthetic leg generally depend on the human interaction forces, which must be measured and canceled by the feedback linearizing control law. This feedback requires expensive multi-axis load cells, and actively canceling the interaction forces may minimize the human's influence over the prosthesis. To address these limitations, this paper proposes a method for projecting virtual constraints into the nullspace of the human interaction terms in the output dynamics. The projected virtual constraints naturally render the output dynamics invariant with respect to the human interaction forces, which instead enter into the internal dynamics of the partially linearized prosthetic system. This method is illustrated with simulations of a transfemoral amputee model walking with a powered knee-ankle prosthesis that is controlled via virtual constraints with and without the proposed projection.

The measurement of principled morality by the Kohlberg Moral Dilemma Questionnaire.

PubMed

Heilbrun, A B; Georges, M

1990-01-01

The four stages preceding the postconventional level in the Kohlberg (1958, 1971, 1976) system of moral development are described as involving moral judgments that conform to external conditions of punishment, reward, social expectation, and conformity to the law. No special level of self-control seems necessary to behave in keeping with these conditions of external reinforcement. In contrast, the two stages of postconventional (principled) mortality involve defiance of majority opinion and defiance of the law--actions that would seem to require greater self-control. This study was concerned with whether postconventional moral reasoning, as measured by the Kohlberg Moral Dilemma Questionnaire (MDQ), can be associated with higher self-control. If so, prediction of principled moral behavior from the MDQ would be based not only on postconventional moral reasoning but bolstered by the necessary level of self-control as well. College students who came the closest to postconventional moral reasoning showed better self-control than college students who were more conventional or preconventional in their moral judgments. These results support the validity of the MDQ for predicting principled moral behavior.

Globalization, international law, and emerging infectious diseases.

PubMed Central

Fidler, D. P.

1996-01-01

The global nature of the threat posed by new and reemerging infectious diseases will require international cooperation in identifying, controlling, and preventing these diseases. Because of this need for international cooperation, international law will certainly play a role in the global strategy for the control of emerging diseases. Recognizing this fact, the World Health Organization has already proposed revising the International Health Regulations. This article examines some basic problems that the global campaign against emerging infectious diseases might face in applying international law to facilitate international cooperation. The international legal component of the global control strategy for these diseases needs careful attention because of problems inherent in international law, especially as it applies to emerging infections issues. PMID:8903206

36 CFR 330.5 - Policy.

Code of Federal Regulations, 2010 CFR

2010-07-01

... reporting requirements and the control of expenditures. (b) Contracts for law enforcement services, as... responsibilities of the State or local law enforcement agencies. (d) Contract law enforcement personnel shall not... regulations shall remain the responsibility of the Corps of Engineers. (e) Contracts for increased law...

Classroom Control: Some Cybernetic Comments on the Possible and the Impossible.

ERIC Educational Resources Information Center

Robinson, Michael

1979-01-01

Application of cybernetic laws and information processing principles suggests that traditional and modern teaching methods are radically incompatible, in the sense that techniques developed in the one cannot be transferred to the other without dislocation of the system as a whole. (Author/WBC)

Active Control of Wind-Tunnel Model Aeroelastic Response Using Neural Networks

NASA Technical Reports Server (NTRS)

Scott, Robert C.

2000-01-01

NASA Langley Research Center, Hampton, VA 23681 Under a joint research and development effort conducted by the National Aeronautics and Space Administration and The Boeing Company (formerly McDonnell Douglas) three neural-network based control systems were developed and tested. The control systems were experimentally evaluated using a transonic wind-tunnel model in the Langley Transonic Dynamics Tunnel. One system used a neural network to schedule flutter suppression control laws, another employed a neural network in a predictive control scheme, and the third employed a neural network in an inverse model control scheme. All three of these control schemes successfully suppressed flutter to or near the limits of the testing apparatus, and represent the first experimental applications of neural networks to flutter suppression. This paper will summarize the findings of this project.

Real time control for NASA robotic gripper

NASA Technical Reports Server (NTRS)

Salter, Carole A.; Baras, John S.

1990-01-01

The ability to easily manipulate objects in a zero gravity environment will pay a key role in future space activities. Emphasis will be placed on robotic manipulation. This will serve to increase astronaut safety and utility in addition to several other benefits. The aim is to develop control laws for the zero gravity robotic end effectors. A hybrid force/position controller will be used. Sensory data available to the controller are obtained from an array of strain gauges and a linear potentiometer. Applying well known optimal control theoretical principles, the control which minimizes the transition time between positions is obtained. A robust force control scheme is developed which allows the desired holding force to be achieved smoothly without oscillation. In addition, an algorithm is found to determine contact force and contact location.

Back-stepping active disturbance rejection control design for integrated missile guidance and control system via reduced-order ESO.

PubMed

Xingling, Shao; Honglun, Wang

2015-07-01

This paper proposes a novel composite integrated guidance and control (IGC) law for missile intercepting against unknown maneuvering target with multiple uncertainties and control constraint. First, by using back-stepping technique, the proposed IGC law design is separated into guidance loop and control loop. The unknown target maneuvers and variations of aerodynamics parameters in guidance and control loop are viewed as uncertainties, which are estimated and compensated by designed model-assisted reduced-order extended state observer (ESO). Second, based on the principle of active disturbance rejection control (ADRC), enhanced feedback linearization (FL) based control law is implemented for the IGC model using the estimates generated by reduced-order ESO. In addition, performance analysis and comparisons between ESO and reduced-order ESO are examined. Nonlinear tracking differentiator is employed to construct the derivative of virtual control command in the control loop. Third, the closed-loop stability for the considered system is established. Finally, the effectiveness of the proposed IGC law in enhanced interception performance such as smooth interception course, improved robustness against multiple uncertainties as well as reduced control consumption during initial phase are demonstrated through simulations. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

Developments in Indian Law from September 1, 1978 through August 31, 1979.

ERIC Educational Resources Information Center

American Indian Journal, 1979

1979-01-01

Law firm analysis which reviews developments in Indian law, discusses holdings and implications of some important Supreme Court decisions (Boldt Case, Yakima Public Law 280 Case, Blackbird Bend Case), analyzes litigation trends which appear to be developing, and comments on the future conduct of Indian litigation. (DS)

Selected advanced aerodynamics and active controls technology concepts development on a derivative B-747

NASA Technical Reports Server (NTRS)

1980-01-01

The feasibility of applying wing tip extensions, winglets, and active control wing load alleviation to the Boeing 747 is investigated. Winglet aerodynamic design methods and high speed wind tunnel test results of winglets and of symmetrically deflected ailerons are presented. Structural resizing analyses to determine weight and aeroelastic twist increments for all the concepts and flutter model test results for the wing with winglets are included. Control law development, system mechanization/reliability studies, and aileron balance tab trade studies for active wing load alleviation systems are discussed. Results are presented in the form of incremental effects on L/D, structural weight, block fuel savings, stability and control, airplane price, and airline operating economics.

Design definition of the Laser Atmospheric Wind Sounder (LAWS), phase 2. Volume 2: Final report

NASA Technical Reports Server (NTRS)

Wilson, D. J.

1992-01-01

Lockheed personnel, along with team member subcontractors and consultants, have performed a preliminary design for the LAWS Instrument. Breadboarding and testing of a LAWS class laser have also been performed. These efforts have demonstrated that LAWS is a feasible Instrument and can be developed with existing state-of-the-art technology. Only a commitment to fund the instrument development and deployment is required to place LAWS in orbit and obtain the anticipated science and operational forecasting benefits. The LAWS Science Team was selected in 1988-89 as were the competing LAWS phase 1/2 contractor teams. The LAWS Science Team developed requirements for the LAWS Instrument, and the NASA/LAWS project office defined launch vehicle and platform design constraints. From these requirements and constraints, the lockheed team developed LAWS Instrument concepts and configurations. A system designed to meet these requirements and constraints is outlined. The LAWS primary subsystem and interfaces - laser, optical, and receiver/processor - required to assemble a lidar are identified. Also identified are the support subsystems required for the lidar to function from space: structures and mechanical, thermal, electrical, and command and data management. The Lockheed team has developed a preliminary design of a LAWS Instrument System consisting of these subsystems and interfaces which will meet the requirements and objectives of the Science Team. This final report provides a summary of the systems engineering analyses and trades of the LAWS. Summaries of the configuration, preliminary designs of the subsystems, testing recommendations, and performance analysis are presented. Environmental considerations associated with deployment of LAWS are discussed. Finally, the successful LAWS laser breadboard effort is discussed along with the requirements and test results.

The composition of heterogeneous control laws

NASA Technical Reports Server (NTRS)

Kuipers, Benjamin; Astrom, Karl

1991-01-01

The fuzzy control literature and industrial practice provide certain nonlinear methods for combining heterogeneous control laws, but these methods have been very difficult to analyze theoretically. An alternate formulation and extension of this approach is presented that has several practical and theoretical benefits. An example of heterogeneous control is given and two alternate analysis methods are presented.

75 FR 7269 - Agency Information Collection Activities; Proposed Collection; Comment Request; Registration and...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-18

... Prevention and Tobacco Control Act (the Tobacco Control Act). DATES: Submit written or electronic comments on... Establishments and Listing of Ingredients in Tobacco Products (OMB Control Number 0910-0650)--Extension On June 22, 2009, the President signed the Tobacco Control Act (Public Law 111-31) into law. The Tobacco...

Two Archetypes of Motor Control Research.

PubMed

Latash, Mark L

2010-07-01

This reply to the Commentaries is focused on two archetypes of motor control research, one based on physics and physiology and the other based on control theory and ideas of neural computations. The former approach, represented by the equilibrium-point hypothesis, strives to discover the physical laws and salient physiological variables that make purposeful coordinated movements possible. The latter approach, represented by the ideas of internal models and optimal control, tries to apply methods of control developed for man-made inanimate systems to the human body. Specific issues related to control with subthreshold membrane depolarization, motor redundancy, and the idea of synergies are briefly discussed.

Impulse damping control of an experimental structure

NASA Technical Reports Server (NTRS)

Redmond, J.; Meyer, J. L.; Silverberg, L.

1993-01-01

The characteristics associated with the fuel optimal control of a harmonic oscillator are extended to develop a near minimum fuel control algorithm for the vibration suppression of spacecraft. The operation of single level thrusters is regulated by recursive calculations of the standard deviations of displacement and velocity resulting in a bang-off-bang controller. A vertically suspended 16 ft cantilevered beam was used in the experiment. Results show that the structure's response was easily manipulated by minor alterations in the control law and the control system performance was not seriously degraded in the presence of multiple actuator failures.

[Impact of the Spanish smoking laws on the exposure to environmental tobacco smoke in Galicia (2005-2011)].

PubMed

Pérez-Ríos, Mónica; Santiago-Pérez, María Isolina; Malvar, Alberto; Jesús García, María; Seoane, Bernardo; Suanzes, Jorge; Hervada, Xurxo

2014-01-01

Prevalence of exposure to environmental tobacco smoke is a valuable index to assess the impact of the laws for tobacco control. The objective of this work is to analyse variations in the prevalence of exposure to environmental tobacco smoke in Galicia (Spain) between 2005, before the Law 28/2005, and 2011, after the law 42/2010. Data were obtained from five population-based independent cross-sectional studies, telephone surveys, developed in Galicia between 2005 and 2011 among population aged 16 to 74 (n=34.419). Self-reported exposure among population aged between 16 and 74 was analysed by setting and tobacco consumption by prevalence with 95% confidence intervals. Environmental tobacco smoke exposure decreased dramatically in Galicia between 2005 and 2011. In 2005, before the Law 28/2005, 95% of the population reported exposure to environmental tobacco smoke compared to 28% in 2011, after the Law 42/2010. Decrease was greater in workplaces in 2006 and in leisure time venues in 2011. After an initial decrease in 2006, exposure at home remains unchanged. An important reduction in self-reported exposure to environmental tobacco smoke occurred in Galicia in the period 2005-2011, specially after the introduction of Laws 28/2005 and 42/2010. Nevertheless, one in four of the population aged 16 to 74 remained exposed in 2011. Copyright © 2013 SESPAS. Published by Elsevier Espana. All rights reserved.

Public health law for the collection and reporting of health care-associated infections.

PubMed

Meier, Benjamin Mason; Stone, Patricia W; Gebbie, Kristine M

2008-10-01

State-based laws for reporting of health care-associated infections (HAI) have developed and changed dramatically in recent years, affecting the costs of reporting and impact on infection rates. It is necessary for practitioners of infection control to understand these changing legal frameworks and their application to practice. Employing systematic state-based research, the researchers have documented legislation and administrative regulations for institution-specific HAI reporting, using this information to create a comprehensive resource on state-based laws for mandatory HAI reporting. As of August 27, 2007, 24 states have adopted laws requiring reporting of HAI rates, with an additional 7 states currently considering legislation that would require HAI reporting and 19 states employing detailed regulation in the absence of any current legislative authorization specific to HAI. This study documents (1) which states require reporting of HAI and, if so, whether this is done by legislation or administrative regulation; (2) whether the specific HAIs to be reported are identified in state law or codified generally as "diseases of public health importance," with reporting specified by administrative regulation; and (3) what reporting policies and procedures are detailed in law. Through analysis of the collected information, the researchers have examined the degree to which states have modernized their respective public health laws to approach mandatory reporting by way of general legislation regarding "matters of public health importance" and subsequent detailed administrative regulation to specify those matters.

Approximate approach for optimization space flights with a low thrust on the basis of sufficient optimality conditions

NASA Astrophysics Data System (ADS)

Salmin, Vadim V.

2017-01-01

Flight mechanics with a low-thrust is a new chapter of mechanics of space flight, considered plurality of all problems trajectory optimization and movement control laws and the design parameters of spacecraft. Thus tasks associated with taking into account the additional factors in mathematical models of the motion of spacecraft becomes increasingly important, as well as additional restrictions on the possibilities of the thrust vector control. The complication of the mathematical models of controlled motion leads to difficulties in solving optimization problems. Author proposed methods of finding approximate optimal control and evaluating their optimality based on analytical solutions. These methods are based on the principle of extending the class of admissible states and controls and sufficient conditions for the absolute minimum. Developed procedures of the estimation enabling to determine how close to the optimal founded solution, and indicate ways to improve them. Authors describes procedures of estimate for approximately optimal control laws for space flight mechanics problems, in particular for optimization flight low-thrust between the circular non-coplanar orbits, optimization the control angle and trajectory movement of the spacecraft during interorbital flights, optimization flights with low-thrust between arbitrary elliptical orbits Earth satellites.

Designing robust control laws using genetic algorithms

NASA Technical Reports Server (NTRS)

Marrison, Chris

1994-01-01

The purpose of this research is to create a method of finding practical, robust control laws. The robustness of a controller is judged by Stochastic Robustness metrics and the level of robustness is optimized by searching for design parameters that minimize a robustness cost function.

Cancellation control law for lateral-directional dynamics of a supermaneuverable aircraft

NASA Technical Reports Server (NTRS)

Snell, Antony

1993-01-01

Cancellation control laws are designed which reduce the high levels of lateral acceleration encountered during aggressive rolling maneuvers executed at high angle of attack. Two independent problem are examined. One is to reduce lateral acceleration at the mass center, while the other focuses on lateral acceleration at the pilot's station, located 7.0 m forward of the mass center. Both of these problems are challenging and somewhat different in their limitations. In each case the design is based on a linearization of the lateral-directional dynamics about a high angle of attack condition. The controllers incorporate dynamic inversion inner loops to provide control of stability-axis roll- and yaw-rates and then employ cancellation filters in both feed-forward and feed-back signal paths. The relative simplicity of the control laws should allow nonlinear generalizations to be devised. Although it is shown that lateral acceleration can be reduced substantially by such control laws, this is at the cost of slowed roll response, poor dutch-roll damping or a combination of the two.

A Generalized-Compliant-Motion Primitive

NASA Technical Reports Server (NTRS)

Backes, Paul G.

1993-01-01

Computer program bridges gap between planning and execution of compliant robotic motions developed and installed in control system of telerobot. Called "generalized-compliant-motion primitive," one of several task-execution-primitive computer programs, which receives commands from higher-level task-planning programs and executes commands by generating required trajectories and applying appropriate control laws. Program comprises four parts corresponding to nominal motion, compliant motion, ending motion, and monitoring. Written in C language.

IRAC Full-Scale Flight Testbed Capabilities

NASA Technical Reports Server (NTRS)

Lee, James A.; Pahle, Joseph; Cogan, Bruce R.; Hanson, Curtis E.; Bosworth, John T.

2009-01-01

Overview: Provide validation of adaptive control law concepts through full scale flight evaluation in a representative avionics architecture. Develop an understanding of aircraft dynamics of current vehicles in damaged and upset conditions Real-world conditions include: a) Turbulence, sensor noise, feedback biases; and b) Coupling between pilot and adaptive system. Simulated damage includes 1) "B" matrix (surface) failures; and 2) "A" matrix failures. Evaluate robustness of control systems to anticipated and unanticipated failures.

Multicriteria Gain Tuning for Rotorcraft Flight Controls (also entitled The Development of the Conduit Advanced Control System Design and Evaluation Interface with a Case Study Application Fly by Wire Helicopter Design)

NASA Technical Reports Server (NTRS)

Biezad, Daniel

1997-01-01

Handling qualities analysis and control law design would seem to be naturally complimenting components of aircraft flight control system design, however these two closely coupled disciplines are often not well integrated in practice. Handling qualities engineers and control system engineers may work in separate groups within an aircraft company. Flight control system engineers and handling quality specialists may come from different backgrounds and schooling and are often not aware of the other group's research. Thus while the handling qualities specifications represent desired aircraft response characteristics, these are rarely incorporated directly in the control system design process. Instead modem control system design techniques are based on servo-loop robustness specifications, and simple representations of the desired control response. Comprehensive handling qualities analysis is often left until the end of the design cycle and performed as a check of the completed design for satisfactory performance. This can lead to costly redesign or less than satisfactory aircraft handling qualities when the flight testing phase is reached. The desire to integrate the fields of handling qualities and flight,control systems led to the development of the CONDUIT system. This tool facilitates control system designs that achieve desired handling quality requirements and servo-loop specifications in a single design process. With CONDUIT, the control system engineer is now able to directly design and control systems to meet the complete handling specifications. CONDUIT allows the designer to retain a preferred control law structure, but then tunes the system parameters to meet the handling quality requirements.

Law of the Minimum paradoxes.

PubMed

Gorban, Alexander N; Pokidysheva, Lyudmila I; Smirnova, Elena V; Tyukina, Tatiana A

2011-09-01

The "Law of the Minimum" states that growth is controlled by the scarcest resource (limiting factor). This concept was originally applied to plant or crop growth (Justus von Liebig, 1840, Salisbury, Plant physiology, 4th edn., Wadsworth, Belmont, 1992) and quantitatively supported by many experiments. Some generalizations based on more complicated "dose-response" curves were proposed. Violations of this law in natural and experimental ecosystems were also reported. We study models of adaptation in ensembles of similar organisms under load of environmental factors and prove that violation of Liebig's law follows from adaptation effects. If the fitness of an organism in a fixed environment satisfies the Law of the Minimum then adaptation equalizes the pressure of essential factors and, therefore, acts against the Liebig's law. This is the the Law of the Minimum paradox: if for a randomly chosen pair "organism-environment" the Law of the Minimum typically holds, then in a well-adapted system, we have to expect violations of this law.For the opposite interaction of factors (a synergistic system of factors which amplify each other), adaptation leads from factor equivalence to limitations by a smaller number of factors.For analysis of adaptation, we develop a system of models based on Selye's idea of the universal adaptation resource (adaptation energy). These models predict that under the load of an environmental factor a population separates into two groups (phases): a less correlated, well adapted group and a highly correlated group with a larger variance of attributes, which experiences problems with adaptation. Some empirical data are presented and evidences of interdisciplinary applications to econometrics are discussed. © Society for Mathematical Biology 2010

Development of a two-dimensional skin friction balance nulling circuit using multivariable control theory

NASA Technical Reports Server (NTRS)

Tripp, John S.; Patek, Stephen D.

1988-01-01

Measurement of planar skin friction forces in aerodynamic testing currently requires installation of two perpendicularly mounted, single-axis balances; consequently, force components must be sensed at two distinct locations. A two-axis instrument developed at the Langley Research Center to overcome this disadvantage allows measurement of a two-dimensional force at one location. This paper describes a feedback-controlled nulling circuit developed for the NASA two-axis balance which, without external compensation, is inherently unstable because of its low friction mechanical design. Linear multivariable control theory is applied to an experimentally validated mathematical model of the balance to synthesize a state-variable feedback control law. Pole placement techniques and computer simulation studies are employed to select eigenvalues which provide ideal transient response with decoupled sensing dynamics.

Anticontrol of Hopf bifurcation and control of chaos for a finance system through washout filters with time delay.

PubMed

Zhao, Huitao; Lu, Mengxia; Zuo, Junmei

2014-01-01

A controlled model for a financial system through washout-filter-aided dynamical feedback control laws is developed, the problem of anticontrol of Hopf bifurcation from the steady state is studied, and the existence, stability, and direction of bifurcated periodic solutions are discussed in detail. The obtained results show that the delay on price index has great influences on the financial system, which can be applied to suppress or avoid the chaos phenomenon appearing in the financial system.

Graduated licensing laws and fatal crashes of teenage drivers: a national study.

PubMed

McCartt, Anne T; Teoh, Eric R; Fields, Michele; Braitman, Keli A; Hellinga, Laurie A

2010-06-01

The objective of the current study was to quantify the effects of the strength of US state graduated driver licensing laws and specific licensing components on the rate of teenage driver fatal crash involvements per 100,000 teenagers during 1996-2007. The strengths of state laws were rated good, fair, marginal, or poor based on a system developed previously by the Insurance Institute for Highway Safety. Analysis was based on quarterly counts of drivers involved in fatal crashes. Associations of overall ratings and individual licensing components with teenage crash rates were evaluated using Poisson regression, with the corresponding fatal crash rate for drivers ages 30-59 controlling for state- or time-dependent influences on crash rates unrelated to graduated licensing laws. Compared with licensing laws rated poor, laws rated good were associated with 30 percent lower fatal crash rates among 15- to 17-year-olds. Laws rated fair yielded fatal crash rates 11 percent lower. The longer the permit age was delayed, or the longer the licensing age was delayed, the lower the estimated fatal crash rates among 15- to 17-year-olds. Stronger nighttime restrictions were associated with larger reductions, and reductions were larger for laws limiting teenage passengers to zero or one than laws allowing two or more teenage passengers or laws without passenger restrictions. After the effects of any related delay in licensure were accounted for, an increase in the minimum learner's permit holding period showed no association with fatal crash rates. An increase in required practice driving hours did not appear to have an independent association with fatal crash rates. Graduated licensing laws that include strong nighttime and passenger restrictions and laws that delay the learner's permit age and licensing age are associated with lower teenage fatal crash rates. States that adopt such laws can expect to achieve substantial reductions in crash deaths.

Control of nonlinear systems with applications to constrained robots and spacecraft attitude stabilization

NASA Technical Reports Server (NTRS)

Krishnan, Hariharan

1993-01-01

This thesis is organized in two parts. In Part 1, control systems described by a class of nonlinear differential and algebraic equations are introduced. A procedure for local stabilization based on a local state realization is developed. An alternative approach to local stabilization is developed based on a classical linearization of the nonlinear differential-algebraic equations. A theoretical framework is established for solving a tracking problem associated with the differential-algebraic system. First, a simple procedure is developed for the design of a feedback control law which ensures, at least locally, that the tracking error in the closed loop system lies within any given bound if the reference inputs are sufficiently slowly varying. Next, by imposing additional assumptions, a procedure is developed for the design of a feedback control law which ensures that the tracking error in the closed loop system approaches zero exponentially for reference inputs which are not necessarily slowly varying. The control design methodologies are used for simultaneous force and position control in constrained robot systems. The differential-algebraic equations are shown to characterize the slow dynamics of a certain nonlinear control system in nonstandard singularly perturbed form. In Part 2, the attitude stabilization (reorientation) of a rigid spacecraft using only two control torques is considered. First, the case of momentum wheel actuators is considered. The complete spacecraft dynamics are not controllable. However, the spacecraft dynamics are small time locally controllable in a reduced sense. The reduced spacecraft dynamics cannot be asymptotically stabilized using continuous feedback, but a discontinuous feedback control strategy is constructed. Next, the case of gas jet actuators is considered. If the uncontrolled principal axis is not an axis of symmetry, the complete spacecraft dynamics are small time locally controllable. However, the spacecraft attitude cannot be asymptotically stabilized using continuous feedback, but a discontinuous stabilizing feedback control strategy is constructed. If the uncontrolled principal axis is an axis of symmetry, the complete spacecraft dynamics cannot be stabilized. However, the spacecraft dynamics are small time locally controllable in a reduced sense. The reduced spacecraft dynamics cannot be asymptotically stabilized using continuous feedback, but again a discontinuous feedback control strategy is constructed.

A novel guidance law using fast terminal sliding mode control with impact angle constraints.

PubMed

Sun, Lianghua; Wang, Weihong; Yi, Ran; Xiong, Shaofeng

2016-09-01

This paper is concerned with the question of, for a missile interception with impact angle constraints, how to design a guidance law. Firstly, missile interception with impact angle constraints is modeled; secondly, a novel guidance law using fast terminal sliding mode control based on extended state observer is proposed to optimize the trajectory and time of interception; finally, for stationary targets, constant velocity targets and maneuvering targets, the guidance law and the stability of the closed loop system is analyzed and the stability of the closed loop system is analyzed, respectively. Simulation results show that when missile and target are on a collision course, the novel guidance law using fast terminal sliding mode control with extended state observer has more optimized trajectory and effectively reduces the time of interception which has a great significance in modern warfare. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

State trajectories used to observe and control dc-to-dc converters

NASA Technical Reports Server (NTRS)

Burns, W. W., III; Wilson, T. G.

1976-01-01

State-plane analysis techniques are employed to study the voltage stepup energy-storage dc-to-dc converter. Within this framework, an example converter operating under the influence of a constant on-time and a constant frequency controller is examined. Qualitative insight gained through this approach is used to develop a conceptual free-running control law for the voltage stepup converter which can achieve steady-state operation in one on/off cycle of control. Digital computer simulation data are presented to illustrate and verify the theoretical discussions presented.

A novel model of motor learning capable of developing an optimal movement control law online from scratch.

PubMed

Shimansky, Yury P; Kang, Tao; He, Jiping

2004-02-01

A computational model of a learning system (LS) is described that acquires knowledge and skill necessary for optimal control of a multisegmental limb dynamics (controlled object or CO), starting from "knowing" only the dimensionality of the object's state space. It is based on an optimal control problem setup different from that of reinforcement learning. The LS solves the optimal control problem online while practicing the manipulation of CO. The system's functional architecture comprises several adaptive components, each of which incorporates a number of mapping functions approximated based on artificial neural nets. Besides the internal model of the CO's dynamics and adaptive controller that computes the control law, the LS includes a new type of internal model, the minimal cost (IM(mc)) of moving the controlled object between a pair of states. That internal model appears critical for the LS's capacity to develop an optimal movement trajectory. The IM(mc) interacts with the adaptive controller in a cooperative manner. The controller provides an initial approximation of an optimal control action, which is further optimized in real time based on the IM(mc). The IM(mc) in turn provides information for updating the controller. The LS's performance was tested on the task of center-out reaching to eight randomly selected targets with a 2DOF limb model. The LS reached an optimal level of performance in a few tens of trials. It also quickly adapted to movement perturbations produced by two different types of external force field. The results suggest that the proposed design of a self-optimized control system can serve as a basis for the modeling of motor learning that includes the formation and adaptive modification of the plan of a goal-directed movement.

Bose-Einstein condensation in chains with power-law hoppings: Exact mapping on the critical behavior in d-dimensional regular lattices.

PubMed

Dias, W S; Bertrand, D; Lyra, M L

2017-06-01

Recent experimental progress on the realization of quantum systems with highly controllable long-range interactions has impelled the study of quantum phase transitions in low-dimensional systems with power-law couplings. Long-range couplings mimic higher-dimensional effects in several physical contexts. Here, we provide the exact relation between the spectral dimension d at the band bottom and the exponent α that tunes the range of power-law hoppings of a one-dimensional ideal lattice Bose gas. We also develop a finite-size scaling analysis to obtain some relevant critical exponents and the critical temperature of the BEC transition. In particular, an irrelevant dangerous scaling field has to be taken into account when the hopping range is sufficiently large to make the effective dimensionality d>4.

Bose-Einstein condensation in chains with power-law hoppings: Exact mapping on the critical behavior in d -dimensional regular lattices

NASA Astrophysics Data System (ADS)

Dias, W. S.; Bertrand, D.; Lyra, M. L.

2017-06-01

Recent experimental progress on the realization of quantum systems with highly controllable long-range interactions has impelled the study of quantum phase transitions in low-dimensional systems with power-law couplings. Long-range couplings mimic higher-dimensional effects in several physical contexts. Here, we provide the exact relation between the spectral dimension d at the band bottom and the exponent α that tunes the range of power-law hoppings of a one-dimensional ideal lattice Bose gas. We also develop a finite-size scaling analysis to obtain some relevant critical exponents and the critical temperature of the BEC transition. In particular, an irrelevant dangerous scaling field has to be taken into account when the hopping range is sufficiently large to make the effective dimensionality d >4 .

Food safety and food labeling from the viewpoint of the consumers.

PubMed

Watanabe, Shaw; Melby, Melissa; Aiba, Naomi

2009-01-01

Distrust of food safety has grown among the Japanese people after the occurrence of bovine spongiform encephalitis (BSE) in 2001. The Food Safety Commission was formed under the Cabinet Office and made a network among the ministries. The newly-established Consumer Agency may strengthen the quick response to emergencies. Shoku-iku (food and dietary education) Law is being implemented by the Cabinet Office with cooperation from relevant ministries and NGOs. Food Sanitation Law and Health Promotion Law are briefly explained, and the necessity of functional nutriology for non-nutrient biologically active substances is described. With regard to public health nutrition, a new food label showing energy balance and antioxidant unit (AOU) as a surrogate marker of fruit and vegetables has been developed for tailor-made nutrition which makes it easy to for individuals to control energy intake.

The Anthropocene - and International Law of the Holocene

NASA Astrophysics Data System (ADS)

Vidas, D.

2012-12-01

Scientists are increasingly voicing a new concern: that the Earth may be undergoing a shift from the most recent known geological epoch, the Holocene (the latest 11,700 years, which have been characterized by relative environmental stability - a factor significant for the development of human civilization), to a new one - the Anthropocene (Zalasiewicz et al., 2010). In 2009, the Anthropocene Working Group was established within the International Commission on Stratigraphy in order to examine the stratigraphic basis for the term 'Anthropocene' and to consider the justification for its possible formalization as the most recent geological time unit. Formal change of the Geological Time Scale due to recognition of the Anthropocene as a new epoch in the geological history of our planet could critically raise awareness and highlight the magnitude of the human impact on the Earth System, prompting fundamental reflection on today's social structures. Important questions may arise about the sustainability of certain aspects of current International Law - a system of rules resting on foundations that evolved under the circumstances of the Holocene, assumed to be ever-lasting. Core challenges for International Law may now be on the horizon. Certain segments of international law, such as the Law of the Sea, involve causal links (historical and ideological) with the development towards the Anthropocene (Vidas, 2011). Other aspects, such as human rights, may gain in prominence and acquire new dimensions - all likely to require fundamental re-examination of accepted perspectives of International Law. The Law of the Sea - a branch of international law that applies to around 71 percent of the Earth's surface area - received its current framework in the near-universal 1982 United Nations Convention on the Law of the Sea (162 parties as of 1 July 2012), which in turn built on some four centuries of development. In our times, however, a thorough re-examination of the Law of the Sea may become necessary. First, with few exceptions, today's Law of the Sea regulates human impacts on the ocean and submarine components of the Earth System in terms of the political boundaries of sovereignty and jurisdiction, translated into law: basically, this is what is expressed through the various maritime zones and the division of jurisdictional competences among coastal and flag states. However, prospects of rising sea-levels and the consequences for the current law-of-the-sea architecture will eventually necessitate deep-going changes in that legal framework. Second, also the ultimate objectives of the current international regulations will need to be re-formulated, and crafted so as to enable us to better channel and confine human impacts on the Earth System. Moreover, some fundamentals of International Law - not least the concept of 'territory' and state control over territory as a constituent element of statehood in international law - may, as we leave the Holocene and enter the Anthropocene, require profound re-examination. REFERENCES: Vidas, D., 2011. The Anthropocene and the International Law of the Sea, Philosophical Transactions of the Royal Society - A, Vol. 369, pp. 909-925. Zalasiewicz, J., M. Williams, W. Steffen and P.J. Crutzen, 2010. The New World of the Anthropocene, Environmental Science & Technology, Vol. 44, pp. 2228-2231.

Florida's Response to Serving Citizens in the Information Age.

ERIC Educational Resources Information Center

Jones, Daryl L.

1995-01-01

Florida's Joint Committee on Information Technology Resources analyzed the impact of technology on the Florida Public Records Law and proposed legislation requiring agencies to consider issues such as encouraging a diversity of sources, the public's right to access, prohibiting monopoly control, and access fees in the development of information…

Opinions of campers and boaters at the Allegheny reservoir

Treesearch

George H. Moeller; Rodney G. Larson; Douglas A. Morrison

1974-01-01

Interviews with 157 campers and 281 boaters near the Allegheny reservoir on the Allegheny National Forest revealed that their perceptions of management problems differed from those of managers. Different users had different attitudes toward recreation use controls, fee policies, recreation zoning, law enforcement, and facility development needs. This diversity...