49 CFR 232.611 - Periodic maintenance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... wiring and brackets; (2) ECP brake system electrical connections; and (3) Car mounted ECP brake system components. (b) Single car air brake test procedures. Prior to placing a freight car equipped with an ECP... car equipped with an ECP brake system shall be inspected and repaired before being released from a...

49 CFR 232.611 - Periodic maintenance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... wiring and brackets; (2) ECP brake system electrical connections; and (3) Car mounted ECP brake system components. (b) Single car air brake test procedures. Prior to placing a freight car equipped with an ECP... car equipped with an ECP brake system shall be inspected and repaired before being released from a...

49 CFR 232.611 - Periodic maintenance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... wiring and brackets; (2) ECP brake system electrical connections; and (3) Car mounted ECP brake system components. (b) Single car air brake test procedures. Prior to placing a freight car equipped with an ECP... car equipped with an ECP brake system shall be inspected and repaired before being released from a...

49 CFR 232.611 - Periodic maintenance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... wiring and brackets; (2) ECP brake system electrical connections; and (3) Car mounted ECP brake system components. (b) Single car air brake test procedures. Prior to placing a freight car equipped with an ECP... car equipped with an ECP brake system shall be inspected and repaired before being released from a...

49 CFR 232.611 - Periodic maintenance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... wiring and brackets; (2) ECP brake system electrical connections; and (3) Car mounted ECP brake system components. (b) Single car air brake test procedures. Prior to placing a freight car equipped with an ECP... car equipped with an ECP brake system shall be inspected and repaired before being released from a...

The design of aircraft brake systems, employing cooling to increase brake life

NASA Technical Reports Server (NTRS)

Scaringe, R. P.; Ho, T. L.; Peterson, M. B.

1975-01-01

A research program was initiated to determine the feasibility of using cooling to increase brake life. An air cooling scheme was proposed, constructed and tested with various designs. Straight and curved slotting of the friction material was tested. A water cooling technique, similar to the air cooling procedure, was evaluated on a curved slotted rotor. Also investigated was the possibility of using a phase-change material within the rotor to absorb heat during braking. Various phase-changing materials were tabulated and a 50%, (by weight) LiF - BeF2 mixing was chosen. It was shown that corrosion was not a problem with this mixture. A preliminary design was evaluated on an actual brake. Results showed that significant improvements in lowering the surface temperature of the brake occurred when air or water cooling was used in conjunction with curved slotted rotors.

Recent studies of tire braking performance. [for aircraft

NASA Technical Reports Server (NTRS)

Mccarty, J. L.; Leland, T. J. W.

1973-01-01

The results from recent studies of some factors affecting tire braking and cornering performance are presented together with a discussion of the possible application of these results to the design of aircraft braking systems. The first part of the paper is concerned with steady-state braking, that is, results from tests conducted at a constant slip ratio or steering angle or both. The second part deals with cyclic braking tests, both single cycle, where brakes are applied at a constant rate until wheel lockup is achieved, and rapid cycling of the brakes under control of a currently operational antiskid system.

Existence and stability of limit cycles in control of anti-lock braking systems with two boundaries via perturbation theory

NASA Astrophysics Data System (ADS)

Köppen, Thomas; Küpper, Tassilo; Makarenkov, Oleg

2017-05-01

This paper presents a two-phase control logic for anti-lock braking systems (ABS). ABS are by now a standard component in every modern car, preventing the wheels from going into a lock situation where the wheels are fixed by the brake and the stopping distances are greatly prolonged. There are different approaches to such control logics. An ABS design proposed in recent literature controls the wheel's slip by creating stable limit cycles in the corresponding phase space. This design is modified via an analytical approach that is derived from perturbation theory. Simulation results document shorter braking distance compared to available tests in the literature.

Hierarchical Control Strategy for the Cooperative Braking System of Electric Vehicle.

PubMed

Peng, Jiankun; He, Hongwen; Liu, Wei; Guo, Hongqiang

2015-01-01

This paper provides a hierarchical control strategy for cooperative braking system of an electric vehicle with separated driven axles. Two layers are defined: the top layer is used to optimize the braking stability based on two sliding mode control strategies, namely, the interaxle control mode and signal-axle control strategies; the interaxle control strategy generates the ideal braking force distribution in general braking condition, and the single-axle control strategy can ensure braking safety in emergency braking condition; the bottom layer is used to maximize the regenerative braking energy recovery efficiency with a reallocated braking torque strategy; the reallocated braking torque strategy can recovery braking energy as much as possible in the premise of meeting battery charging power. The simulation results show that the proposed hierarchical control strategy is reasonable and can adapt to different typical road surfaces and load cases; the vehicle braking stability and safety can be guaranteed; furthermore, the regenerative braking energy recovery efficiency can be improved.

Hierarchical Control Strategy for the Cooperative Braking System of Electric Vehicle

PubMed Central

Peng, Jiankun; He, Hongwen; Guo, Hongqiang

2015-01-01

This paper provides a hierarchical control strategy for cooperative braking system of an electric vehicle with separated driven axles. Two layers are defined: the top layer is used to optimize the braking stability based on two sliding mode control strategies, namely, the interaxle control mode and signal-axle control strategies; the interaxle control strategy generates the ideal braking force distribution in general braking condition, and the single-axle control strategy can ensure braking safety in emergency braking condition; the bottom layer is used to maximize the regenerative braking energy recovery efficiency with a reallocated braking torque strategy; the reallocated braking torque strategy can recovery braking energy as much as possible in the premise of meeting battery charging power. The simulation results show that the proposed hierarchical control strategy is reasonable and can adapt to different typical road surfaces and load cases; the vehicle braking stability and safety can be guaranteed; furthermore, the regenerative braking energy recovery efficiency can be improved. PMID:26236772

Improvements to a five-phase ABS algorithm for experimental validation

NASA Astrophysics Data System (ADS)

Gerard, Mathieu; Pasillas-Lépine, William; de Vries, Edwin; Verhaegen, Michel

2012-10-01

The anti-lock braking system (ABS) is the most important active safety system for passenger cars. Unfortunately, the literature is not really precise about its description, stability and performance. This research improves a five-phase hybrid ABS control algorithm based on wheel deceleration [W. Pasillas-Lépine, Hybrid modeling and limit cycle analysis for a class of five-phase anti-lock brake algorithms, Veh. Syst. Dyn. 44 (2006), pp. 173-188] and validates it on a tyre-in-the-loop laboratory facility. Five relevant effects are modelled so that the simulation matches the reality: oscillations in measurements, wheel acceleration reconstruction, brake pressure dynamics, brake efficiency changes and tyre relaxation. The time delays in measurement and actuation have been identified as the main difficulty for the initial algorithm to work in practice. Three methods are proposed in order to deal with these delays. It is verified that the ABS limit cycles encircle the optimal braking point, without assuming any tyre parameter being a priori known. The ABS algorithm is compared with the commercial algorithm developed by Bosch.

Vehicle speed affects both pre-skid braking kinematics and average tire/roadway friction.

PubMed

Heinrichs, Bradley E; Allin, Boyd D; Bowler, James J; Siegmund, Gunter P

2004-09-01

Vehicles decelerate between brake application and skid onset. To better estimate a vehicle's speed and position at brake application, we investigated how vehicle deceleration varied with initial speed during both the pre-skid and skidding intervals on dry asphalt. Skid-to-stop tests were performed from four initial speeds (20, 40, 60, and 80 km/h) using three different grades of tire (economy, touring, and performance) on a single vehicle and a single road surface. Average skidding friction was found to vary with initial speed and tire type. The post-brake/pre-skid speed loss, elapsed time, distance travelled, and effective friction were found to vary with initial speed. Based on these data, a method using skid mark length to predict vehicle speed and position at brake application rather than skid onset was shown to improve estimates of initial vehicle speed by up to 10 km/h and estimates of vehicle position at brake application by up to 8 m compared to conventional methods that ignore the post-brake/pre-skid interval. Copyright 2003 Elsevier Ltd.

Driver Behavioral Changes through Interactions with an Automatic Brake System for Collision Avoidance

NASA Astrophysics Data System (ADS)

Itoh, Makoto; Fujiwara, Yusuke; Inagaki, Toshiyuki

This paper discusses driver's behavioral changes as a result of driver's use of an automatic brake system for preventing a rear-end collision from occurring. Three types of automatic brake systems are investigated in this study. Type 1 brake system applies a strong automatic brake when a collision is very imminent. Type 2 brake system initiates brake operation softly when a rear-end crash may be anticipated. Types 1 and 2 are for avoidance of a collision. Type 3 brake system, on the other hand, applies a strong automatic brake to reduce the damage when a collision can not be avoided. An experiment was conducted with a driving simulator in order to analyze the driver's possible behavioral changes. The results showed that the time headway (THW) during car following phase was reduced by use of an automatic brake system of any type. The inverse of time to collision (TTC), which is an index of the driver's brake timing, increased by use of Type 1 brake system when the deceleration rate of the lead vehicle was relatively low. However, the brake timing did not change when the drivers used Type 2 or 3 brake system. As a whole, dangerous behavioral changes, such as overreliance on a brake system, were not observed for either type of brake system.

Analysis and flight evaluation of a small, fixed-wing aircraft equipped with hinged plate spoilers

NASA Technical Reports Server (NTRS)

Olcott, J. W.; Sackel, E.; Ellis, D. R.

1981-01-01

The results of a four phase effort to evaluate the application of hinged plate spoilers/dive brakes to a small general aviation aircraft are presented. The test vehicle was a single engine light aircraft modified with an experimental set of upper surface spoilers and lower surface dive brakes similar to the type used on sailplanes. The lift, drag, stick free stability, trim, and dynamic response characteristics of four different spoiler/dive brake configurations were determined. Tests also were conducted, under a wide range of flight conditions and with pilots of various experience levels, to determine the most favorable methods of spoiler control and to evaluate how spoilers might best be used during the approach and landing task. The effects of approach path angle, approach airspeed, and pilot technique using throttle/spoiler integrated control were investigated for day, night, VFR, and IFR approaches and landings. The test results indicated that spoilers offered significant improvements in the vehicle's performance and flying qualities for all elements of the approach and landing task, provided a suitable method of control was available.

49 CFR 571.122 - Standard No. 122; Motorcycle brake systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... mile before any brake application. Skid number means the frictional resistance of a pavement measured... control designed so that a leakage-type failure of a pressure component in a single subsystem (except... pounds). S5.8Service brake system design durability. Each motorcycle shall be capable of completing all...

Augmented Cognition - Phase 4 Cognitive Assessment and Task Management (CAT-M)

DTIC Science & Technology

2008-12-01

Angle Brake Pedal Force Accelerator Pedal ...Wheel Angle • Brake Pedal Force • Accelerator Pedal Deflection Note that we are using the controls as input to the prediction system. This means... Angle . At time >2.5 seconds, the Accelerator Pedal and Brake Pedal become statistically significantly easier to predict than Steering Wheel Angle .

49 CFR 571.122a - Standard No. 122; Motorcycle brake systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... application. Skid number means the frictional resistance of a pavement measured in accordance with ASTM E274... brake system consisting of two or more subsystems actuated by a single control designed so that a...), but not less than 0 Newtons (0 pounds). S5.8Service brake system design durability. Each motorcycle...

49 CFR 571.122a - Standard No. 122; Motorcycle brake systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... application. Skid number means the frictional resistance of a pavement measured in accordance with ASTM E274... brake system consisting of two or more subsystems actuated by a single control designed so that a...), but not less than 0 Newtons (0 pounds). S5.8Service brake system design durability. Each motorcycle...

49 CFR 571.122 - Standard No. 122; Motorcycle brake systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... mile before any brake application. Skid number means the frictional resistance of a pavement measured... subsystems actuated by a single control designed so that a leakage-type failure of a pressure component in a...), but not less than 0 Newtons (0 pounds). S5.8Service brake system design durability. Each motorcycle...

49 CFR 571.122 - Standard No. 122; Motorcycle brake systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... mile before any brake application. Skid number means the frictional resistance of a pavement measured... subsystems actuated by a single control designed so that a leakage-type failure of a pressure component in a...), but not less than 0 Newtons (0 pounds). S5.8Service brake system design durability. Each motorcycle...

49 CFR 232.305 - Single car air brake tests.

Code of Federal Regulations, 2010 CFR

2010-10-01

... document at the Federal Railroad Administration, Docket Clerk, 1200 New Jersey Avenue, SE., Washington, DC... brake left applied; (ii) Slid flat wheel, unless known to be caused by hand brake left applied; or (iii... shall be performed on each new or rebuilt car prior to placing or using the car in revenue service. [66...

49 CFR 232.305 - Single car air brake tests.

Code of Federal Regulations, 2011 CFR

2011-10-01

... document at the Federal Railroad Administration, Docket Clerk, 1200 New Jersey Avenue, SE., Washington, DC... brake left applied; (ii) Slid flat wheel, unless known to be caused by hand brake left applied; or (iii... shall be performed on each new or rebuilt car prior to placing or using the car in revenue service. [66...

NHTSA light vehicle antilock brake systems research program task 5, part 1 : examination of drivers' collision avoidance behavior using conventional and antilock brake systems on the Iowa driving simulator

DOT National Transportation Integrated Search

2000-08-01

The National Highway Traffic Safety Administration (NHTSA) has developed its Light Vehicle Antilock Brake Systems (ABS) Research Program in an effort to determine the cause(s) of the apparent increase in single-vehicle run-off-road crashes and decrea...

A simplified flight-test method for determining aircraft takeoff performance that includes effects of pilot technique

NASA Technical Reports Server (NTRS)

Larson, T. J.; Schweikhard, W. G.

1974-01-01

A method for evaluating aircraft takeoff performance from brake release to air-phase height that requires fewer tests than conventionally required is evaluated with data for the XB-70 airplane. The method defines the effects of pilot technique on takeoff performance quantitatively, including the decrease in acceleration from drag due to lift. For a given takeoff weight and throttle setting, a single takeoff provides enough data to establish a standardizing relationship for the distance from brake release to any point where velocity is appropriate to rotation. The lower rotation rates penalized takeoff performance in terms of ground roll distance; the lowest observed rotation rate required a ground roll distance that was 19 percent longer than the highest. Rotations at the minimum rate also resulted in lift-off velocities that were approximately 5 knots lower than the highest rotation rate at any given lift-off distance.

Behavior of aircraft antiskid braking systems on dry and wet runway surfaces. A slip-velocity-controlled, pressure-bias-modulated system

NASA Technical Reports Server (NTRS)

Stubbs, S. M.; Tanner, J. A.; Smith, E. G.

1979-01-01

The braking and cornering response of a slip velocity controlled, pressure bias modulated aircraft antiskid braking system is investigated. The investigation, conducted on dry and wet runway surfaces, utilized one main gear wheel, brake, and tire assembly of a McDonnell Douglas DC 9 series 10 airplane. The landing gear strut was replaced by a dynamometer. The parameters, which were varied, included the carriage speed, tire loading, yaw angle, tire tread condition, brake system operating pressure, and runway wetness conditions. The effects of each of these parameters on the behavior of the skid control system is presented. Comparisons between data obtained with the skid control system and data obtained from single cycle braking tests without antiskid protection are examined.

49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

Code of Federal Regulations, 2011 CFR

2011-10-01

... vehicles manufactured prior to March 1, 1975. For vehicles, manufactured on or after March 1, 1975, the... in 1 minute for single vehicles or more than 3 psi in 1 minute for combination vehicles, with the... psi in 1 minute for single vehicles or more than 4 psi in 1 minute for combination vehicles, with the...

Real-Time Dynamic Brake Assessment Proof of Concept Final Report

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

Lascurain, Mary Beth; Franzese, Oscar; Capps, Gary J

This proof-of-concept research was performed to explore the feasibility of using real-world braking data from commercial motor vehicles to make a diagnosis of brake condition similar to that of the performance-based brake tester (PBBT). This was done by determining the relationship between pressure and brake force (P-BF), compensating for the gross vehicle weight (GVW). The nature of this P-BF relationship (e.g., low braking force for a given brake application pressure) may indicate brake system problems. In order to determine the relationship between brake force and brake application pressure, a few key parameters of duty cycle information were collected. Because brakingmore » events are often brief, spanning only a few seconds, a sample rate of 10 Hz was needed. The algorithm under development required brake application pressure and speed (from which deceleration was calculated). Accurate weight estimation was also needed to properly derive the braking force from the deceleration. In order to ensure that braking force was the predominant factor in deceleration for the segments of data used in analysis, the data was screened for grade as well. Also, the analysis needed to be based on pressures above the crack pressure. The crack pressure is the pressure below which the individual brakes are not applied due the nature of the mechanical system. This value, which may vary somewhat from one wheel end to another, is approximately 10 psi. Therefore, only pressures 15 psi and above were used in the analysis. The Department of Energy s Medium Truck Duty Cycle research has indicated that under the real-world circumstances of the test vehicle brake pressures of up to approximately 30 psi can be expected. Several different types of data were collected during the testing task of this project. Constant-pressure stopping tests were conducted at several combinations of brake application pressure (15, 20, 25, and 30 psi), load conditions (moderately and fully laden), and speeds (20 and 30 mph). Data was collected at 10 Hz. Standard and stepped-pressure performance-based brake tests with brake pressure transducers were performed for each loading condition. The stepped-pressure test included the constant-pressure intervals of brake application at 15, 20, 25, and 30 psi. The PBBT data files included 10 Hz streaming data collected during the testing of each axle. Two weeks of real-world duty cycle (driving and braking) data was also collected at 10 Hz. Initial analysis of the data revealed that the data collected in the field (i.e., day-to-day operations) provided the same information as that obtained from the controlled tests. Analysis of the data collected revealed a strong linear relationship between brake application pressure and deceleration for given GVWs. As anticipated, initial speed was not found to be a significant factor in the deceleration-pressure relationship, unlike GVW. The positive results obtained from this proof of concept test point to the need for further research to expand this concept. A second phase should include testing over a wider range of speeds and include medium brake application pressures in addition to the low pressures tested in this research. Testing on multiple vehicles would also be of value. This future phase should involve testing to determine how degradation of braking performance affects the pressure-deceleration relationship.« less

The effect of a braking device in reducing the ground impact forces inherent in plyometric training.

PubMed

Humphries, B J; Newton, R U; Wilson, G J

1995-02-01

As a consequence of performing plyometric type exercises, such as depth jumps, impact forces placed on the musculoskeletal system during landing can lead to a potential for injury. A reduction of impact forces upon landing could therefore contribute to reduce the risk of injury. Twenty subjects performed a series of loaded jumps for maximal height, with and without a brake mechanism designed to reduce impact force during landing. The braked jumps were performed on the Plyometric Power System (PPS) with its braking mechanism set at 75% of body weight during the downward phase. The non-braked condition involved jumps with no braking. Vertical ground reaction force data, sampled for 5.5 s at 550 Hz from a Kistler forceplate, were collected for each jump condition. The following parameters were then calculated: peak vertical force, time to peak force, passive impact impulse and maximum concentric force. The brake served to significantly (p < 0.01) reduce peak impact force by 155% and passive impact impulse by 200%. No significant differences were found for peak concentric force production. The braking mechanism of the PPS significantly reduced ground impact forces without impeding concentric force production. The reduction in eccentric loading, using the braking mechanism, may reduce the incidence of injury associated with landings from high intensity plyometric exercises.

Motion Perception and Driving: Predicting Performance Through Testing and Shortening Braking Reaction Times Through Training

DTIC Science & Technology

2013-12-01

brake reaction time on the EB test from pre-post while there was no significant change for the control group : t(38)=2.24, p=0.03. Tests of 3D motion...0.61). In experiment 2, the motion perception training group had a significant decrease in brake reaction time on the EB test from pre- to...the following. The experiment was divided into 8 phases: a pretest , six training blocks (once per week), and a posttest . Participants were allocated

Powered wheel for aircraft

NASA Technical Reports Server (NTRS)

Long, M. J.; Irick, S. C.; Van Ausdal, R. K.

1977-01-01

Single integral unit includes motor, gearbox, and clutch. Device has two-speed capability, fits within aerodynamic contours of aircraft, operates with onboard power source, does not interfere with normal landing gear functions, reduces use of regular brakes in congested areas, and provides locomotion and supplementary braking capability.

Performance tests of a single-cylinder compression-ignition engine with a displacer piston

NASA Technical Reports Server (NTRS)

Moore, C S; Foster, H H

1935-01-01

Engine performance was investigated using a rectangular displacer on the piston crown to cause a forced air flow in a vertical-disk combustion chamber of a single-cylinder, 4-stroke-cycle compression-ignition engine. The optimum air-flow area was determined first with the area concentrated at one end of the displacer and then with the area equally divided between two passages, one at each end of the displacer. Best performance was obtained with the two-passage air flow arranged to give a calculated maximum air-flow speed of 8 times the linear crank-pin speed. With the same fuel-spray formation as used without the air flow, the maximum clear exhaust brake mean effective pressure at 1,500 r.p.m. was increased from 90 to 115 pounds per square inch and the corresponding fuel consumption reduced from 0.46 to 0.43 pound per brake horsepower-hour. At 1,200 r.p.m., a maximum clear exhaust brake mean effective pressure of 120 pounds per square inch was obtained at a fuel consumption of 0.42 pound per brake horsepower-hour. At higher specific fuel consumption the brake mean effective pressure was still increasing rapidly.

Four quadrant control circuit for a brushless three-phase dc motor

NASA Technical Reports Server (NTRS)

Nola, Frank J. (Inventor)

1987-01-01

A control circuit is provided for a brushless three-phase dc motor which affords four quadrant control from a single command. The control circuit probes acceleration of the motor in both clockwise and counterclockwise directions and braking and generation in both clockwise and counterclockwise directions. In addition to turning on individual transistors of the transistor pairs connected to the phase windings of the motor for 120 deg periods while the other transistor of that pair is off, the control circuit also provides, in a future mode of operation, turning the two transistors of each pair on and off alternately at a phase modulation frequency during such a 120 deg period. A feedback signal is derived which is proportional to the motor current and which has a polarity consistent with the command signal, such that negative feedback results.

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

Ekşi, K. Y.; Andaç, I. C.; Çıkıntoğlu, S.

The recently discovered rotationally powered pulsar PSR J1640–4631 is the first to have a braking index measured, with high enough precision, that is greater than 3. An inclined magnetic rotator in vacuum or plasma would be subject not only to spin-down but also to an alignment torque. The vacuum model can address the braking index only for an almost orthogonal rotator, which is incompatible with the single-peaked pulse profile. The magnetic dipole model with the corotating plasma predicts braking indices between 3 and 3.25. We find that the braking index of 3.15 is consistent with two different inclination angles, 18.°5more » ± 3° and 56° ± 4°. The smaller angle is preferred given that the pulse profile has a single peak and the radio output of the source is weak. We infer the change in the inclination angle to be at the rate −0.°23 per century, three times smaller in absolute value than the rate recently observed for the Crab pulsar.« less

Loads Acting on the Mine Conveyance Attachments and Tail Ropes during the Emergency Braking in the Event of an Overtravel

NASA Astrophysics Data System (ADS)

Wolny, Stanisław

2016-09-01

It has now become the common practice among the design engineers that in dimensioning of structural components of conveyances, particularly the load bearing elements, they mostly use methods that do not enable the predictions of their service life, instead they rely on determining the safety factor related to the static loads exclusively. In order to solve the problem, i.e. to derive and verify the key relationships needed to determine the fatigue endurance of structural elements of conveyances expressed in the function of time and taking into account the type of hoisting gear, it is required that the values of all loads acting upon the conveyance should be determined, including those experienced under the emergency conditions, for instance during the braking phase in the event of overtravel. This study relies on the results of dynamic analysis of a hoisting installation during the braking phase when the conveyance approaches the topmost or lowermost levels. For the assumed model of the system, the equations of motion are derived for the hoisting and tail rope elements and for the elastic strings. The section of the hoisting rope between the full conveyance approaching the top station and the Keope pulley is substituted by a spring with the constant elasticity coefficient, equal to that of the rope section at the instant the conveyance begins the underwind travel. Recalling the solution to the wave equation, analytical formulas are provided expressing the displacements of any cross-profiles of hoisting and tail ropes, including the conveyance attachments and tail ropes, in the function of braking forces applied to conveyances in the overtravel path and operational parameters of the hoisting gear. Besides, approximate formulas are provided yielding: loading of the hoisting rope segment between the conveyance braking in the headgear tower and the Keope pulley deceleration of the conveyance during the braking phase. The results will be utilised to derive the function governing the conveyance load variations during the emergency braking, depending on the parameters of the hoisting installations and the braking systems. These relationships are required for adequate design of the frictional contact between the ropes and the pulley and will become the basic criteria for dimensioning and design of load-bearing components of conveyances in the context of improving their reliability and safety features.

Integrated Targeting and Guidance for Powered Planetary Descent

NASA Astrophysics Data System (ADS)

Azimov, Dilmurat M.; Bishop, Robert H.

2018-02-01

This paper presents an on-board guidance and targeting design that enables explicit state and thrust vector control and on-board targeting for planetary descent and landing. These capabilities are developed utilizing a new closed-form solution for the constant thrust arc of the braking phase of the powered descent trajectory. The key elements of proven targeting and guidance architectures, including braking and approach phase quartics, are employed. It is demonstrated that implementation of the proposed solution avoids numerical simulation iterations, thereby facilitating on-board execution of targeting procedures during the descent. It is shown that the shape of the braking phase constant thrust arc is highly dependent on initial mass and propulsion system parameters. The analytic solution process is explicit in terms of targeting and guidance parameters, while remaining generic with respect to planetary body and descent trajectory design. These features increase the feasibility of extending the proposed integrated targeting and guidance design to future cargo and robotic landing missions.

Integrated Targeting and Guidance for Powered Planetary Descent

NASA Astrophysics Data System (ADS)

Azimov, Dilmurat M.; Bishop, Robert H.

2018-06-01

This paper presents an on-board guidance and targeting design that enables explicit state and thrust vector control and on-board targeting for planetary descent and landing. These capabilities are developed utilizing a new closed-form solution for the constant thrust arc of the braking phase of the powered descent trajectory. The key elements of proven targeting and guidance architectures, including braking and approach phase quartics, are employed. It is demonstrated that implementation of the proposed solution avoids numerical simulation iterations, thereby facilitating on-board execution of targeting procedures during the descent. It is shown that the shape of the braking phase constant thrust arc is highly dependent on initial mass and propulsion system parameters. The analytic solution process is explicit in terms of targeting and guidance parameters, while remaining generic with respect to planetary body and descent trajectory design. These features increase the feasibility of extending the proposed integrated targeting and guidance design to future cargo and robotic landing missions.

Gait biomechanics of skipping are substantially different than those of running.

PubMed

McDonnell, Jessica; Willson, John D; Zwetsloot, Kevin A; Houmard, Joseph; DeVita, Paul

2017-11-07

The inherit injury risk associated with high-impact exercises calls for alternative ways to achieve the benefits of aerobic exercise while minimizing excessive stresses to body tissues. Skipping presents such an alternative, incorporating double support, flight, and single support phases. We used ground reaction forces (GRFs), lower extremity joint torques and powers to compare skipping and running in 20 healthy adults. The two consecutive skipping steps on each limb differed significantly from each other, and from running. Running had the longest step length, the highest peak vertical GRF, peak knee extensor torque, and peak knee negative and positive power and negative and positive work. Skipping had the greater cadence, peak horizontal GRF, peak hip and ankle extensor torques, peak ankle negative power and work, and peak ankle positive power. The second vs first skipping step had the shorter step length, higher cadence, peak horizontal GRF, peak ankle extensor torque, and peak ankle negative power, negative work, and positive power and positive work. The first skipping step utilized predominately net negative joint work (eccentric muscle action) while the second utilized predominately net positive joint work (concentric muscle action). The skipping data further highlight the persistence of net negative work performed at the knee and net positive work performed at the ankle across locomotion gaits. Evidence of step segregation was seen in distribution of the braking and propelling impulses and net work produced across the hip, knee, and ankle joints. Skipping was substantially different than running and was temporally and spatially asymmetrical with successive foot falls partitioned into a dominant function, either braking or propelling whereas running had a single, repeated step in which both braking and propelling actions were performed equally. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of Combustion-chamber Shape on the Performance of a Prechamber Compression-ignition Engine

NASA Technical Reports Server (NTRS)

Moore, C S; Collins, J H , Jr

1934-01-01

The effect on engine performance of variations in the shape of the prechamber, the shape and direction of the connecting passage, the chamber volume using a tangential passage, the injection system, and the direction od the fuel spray in the chamber was investigated using a 5 by 7 inch single-cylinder compression-ignition engine. The results show that the performance of this engine can be considerably improved by selecting the best combination of variables and incorporating them in a single design. The best combination as determined from these tests consisted of a disk-shaped chamber connected to the cylinder by means of a flared tangential passage. The fuel was injected through a single-orifice nozzle directed normal to the air swirl and in the same plane. At an engine speed of 1,500 r.p.m. and with the theoretical fuel quantity for no excess air, the engine developed a brake mean effective pressure of 115 pounds per square inch with a fuel consumption of 0.49 pound per brake horsepower-hour and an explosion pressure of 820 pounds per square inch. A brake mean effective pressure of 100 pounds per square inch with a brake-fuel consumption of 0.44 pound per horsepower-hour at 1,500 r.p.m. was obtained.

49 CFR 571.123 - Standard No. 123; Motorcycle controls and displays.

Code of Federal Regulations, 2010 CFR

2010-10-01

... handgrip. If a motorcycle with an automatic clutch other than a scooter is equipped with a supplemental rear brake control, the control shall be located on the left handlebar. If a scooter with an automatic... equipped with self-proportioning or antilock braking devices utilizing a single control for front and rear...

An Experimental Investigation of the Effect of Propellers Used as Aerodynamic Brakes on Stability and Control

NASA Technical Reports Server (NTRS)

Hanson, Frederick H

1945-01-01

Tests were made of a model representative of a single-engine tractor-type airplane for the purpose of determining the stability and control effects of a propeller used as an aerodynamic brake. The tests were made with single-and dual-rotation propellers to show the effect of type of propeller rotation, and with positive thrust to provide basic data with which to compare the effects of negative thrust. Four configurations of the model were used to give the effects of tilting the propeller thrust axis down 5 deg., raising the horizontal tail, and combining both tilt and raised tail. Results of the tests are reported herein. The effects of negative thrust were found to be significant. The longitudinal stability was increased because of the loss of wing lift and increase of the angle of attack of the tail. Directional stability and both longitudinal and directional control were decreased because of the reduced velocity at the tail. These effects are moderate for moderate braking but become pronounced with full-power braking, particularly at high values of lift coefficient. The effects of model configuration changes were small when compared with the over-all effects of negative-thrust operation; however, improved stability and control characteristics were exhibited by the model with the tilted thrust axis. Raising the horizontal tail improved the longitudinal characteristics, but was detrimental to directional characteristics. The use of dual-rotation propeller reduced the directional trim charges resulting from the braking operation. A prototype airplane was assumed and handling qualities were computed and analyzed for normal (positive thrust) and braking operation with full and partial power. The results of these analyses are presented for the longitudinal characteristics in steady and accelerated flight, and for the directional characteristics in high- and low-speed flight. It was found that by limiting the power output of the engine (assuming the constant-speed propeller will function in the range of blade angles required for negative thrust) the stability and control characteristics may be held within the limits required for safe operation. Braking with full power, particularly at low speeds, is dangerous, but braking with very small power output is satisfactory from the standpoint of control. The amount of braking produced with zero power output is equal to or better than that produced by conventional spoiler-type brakes.

Phase 1 Feasibility Study: Seawater Hydraulic Transfer Pump

DTIC Science & Technology

1996-11-01

2442532 3408040 M/ DIRECT HYDRAULIC DRIVE FOR LARGE FLOTATION CELLS 2440714 3406737 A-5 M/ COMBINED ANTISKID AND TRACTION CONTROL ELECTRONIC BRAKE SYSTEM ...HYDRAULIC PRESSURE 2449168 3412870 M/ POWER STEERING PUMP WITH BALANCED PORTING 2446911 3411257 M/ HYDRAULIC BRAKE SYSTEM INCLUDING SLIP CONTROL ...2440401 3406424 M/ HYDRAULIC CIRCUIT FOR RUNNING A CRAWLER VEHICLE 2434313 3402015 M/ HYDRAULICALLY ACTUATED AIRCRAFT ENGINE CONTROL SYSTEM 2425918

Analysis of heat conduction in a drum brake system of the wheeled armored personnel carriers

NASA Astrophysics Data System (ADS)

Puncioiu, A. M.; Truta, M.; Vedinas, I.; Marinescu, M.; Vinturis, V.

2015-11-01

This paper is an integrated study performed over the Braking System of the Wheeled Armored Personnel Carriers. It mainly aims to analyze the heat transfer process which is present in almost any industrial and natural process. The vehicle drum brake systems can generate extremely high temperatures under high but short duration braking loads or under relatively light but continuous braking. For the proper conduct of the special vehicles mission in rough terrain, we are talking about, on one hand, the importance of the possibility of immobilization and retaining position and, on the other hand, during the braking process, the importance movement stability and reversibility or reversibility, to an encounter with an obstacle. Heat transfer processes influence the performance of the braking system. In the braking phase, kinetic energy transforms into thermal energy resulting in intense heating and high temperature states of analyzed vehicle wheels. In the present work a finite element model for the temperature distribution in a brake drum is developed, by employing commercial finite element software, ANSYS. These structural and thermal FEA models will simulate entire braking event. The heat generated during braking causes distortion which modifies thermoelastic contact pressure distribution drum-shoe interface. In order to capture the effect of heat, a transient thermal analysis is performed in order to predict the temperature distribution transitional brake components. Drum brakes are checked both mechanical and thermal. These tests aim to establish their sustainability in terms of wear and the variation coefficient of friction between the friction surfaces with increasing temperature. Modeling using simulation programs led eventually to the establishment of actual thermal load of the mechanism of brake components. It was drawn the efficiency characteristic by plotting the coefficient of effectiveness relative to the coefficient of friction shoe-drum. Thus induced thermal loads determine thermo mechanical behavior of the structure of wheels. Study the transfer of heat generated during braking is useful because results can improve and validate existing theory or may lead to the development of a mathematical model to simulate the behavior of the brake system for various tactical and operational situations. Conclusions of this paper are relevant because theoretical data analysis results are validated by experimental research.

DISC BRAKE SYSTEM (CENTER), INCLUDING BELT DRIVE TO SECONDARY GENERAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

DISC BRAKE SYSTEM (CENTER), INCLUDING BELT DRIVE TO SECONDARY GENERAL MOTORS ENGINE (LEFT)AND FERREL REDUCTION GEAR CONNECTION TO ALLIS-CHALMERS DIESEL ENGINE (RIGHT), LOOKING NORTH. NOTE TORQUE CONVERTER (TOP) AND THROTTLE (BELOW) LINES CONNECTING TO PRIMARY ENGINE. - Mad River Glen, Single Chair Ski Lift, 62 Mad River Glen Resort Road, Fayston, Washington County, VT

The effect of suppressors and muzzle brakes on shock wave strength

NASA Astrophysics Data System (ADS)

Phan, K. C.; Stollery, J. L.

Experimental simulations of a gun blast were performed in the course of an optimization study of shock-wave suppressor and muzzle-brake geometry. A single-spark schlieren system was used to photograph the shock waves emerging from a 32-mm shock tube. The suppressor systems tested with respect to the overpressure level included a perforated tube enclosed in an expansion chamber, a cup-and-box suppressor, and noise-absorbent materials inside a suppressor; high suppression efficiency was observed for the first two. Recoil simulation tests, performed with plain and pyramidal baffles, disk, and cylinder, show that the blast level is generally higher for a more efective muzzle brake. An optimum distance from the muzzle to the brake is suggested to be in the region of one caliber.

Aluminum runway surface as possible aid to aircraft braking

NASA Technical Reports Server (NTRS)

Miller, C. D.; Pinkel, I. I.

1973-01-01

Several concepts are described for use singly or in combination to improve aircraft braking. All involve a thin layer of aluminum covering all or part of the runway. Advantage would derive from faster heat conduction from the tire-runway interface. Heating of tread surface with consequent softening and loss of friction coefficient should be reduced. Equations are developed indicating that at least 99 percent of friction heat should flow into the aluminum. Preliminary test results indicate a coefficient of sliding friction of 1.4, with predictably slight heating of tread. Elimination of conventional brakes is at least a remote possibility.

A New, Low Braking Index for the LMC Pulsar B0540-69

NASA Technical Reports Server (NTRS)

Marshall, F. E.; Guillemot, L.; Harding, A. K.; Martin, P.; Smith, D. A.

2016-01-01

We report the results of a 16-month monitoring campaign using the Swift satellite of PSR 0540, a young pulsar in the Large Magellanic Cloud. Phase connection was maintained throughout the campaign so that a reliable ephemeris could be determined, and the length of the campaign is adequate to accurately determine the spin frequency and its first and second derivatives. The braking index n is 0.031 +/- 0.013 (90% confidence), a value much lower than previously reported for 0 540 and almost all other young pulsars. We use data from the extensive monitoring campaign with RXTE to showt hat timing noise is unlikely to significantly affect the measurement. This is the first measurement of the braking index in the pulsars recently discovered high spin-down state. We discuss possible mechanisms for producing the low braking index.

Do the peak and mean force methods of assessing vertical jump force asymmetry agree?

PubMed

Lake, Jason P; Mundy, Peter D; Comfort, Paul; Suchomel, Timothy J

2018-05-21

The aim of this study was to assess agreement between peak and mean force methods of quantifying force asymmetry during the countermovement jump (CMJ). Forty-five men performed four CMJ with each foot on one of two force plates recording at 1,000 Hz. Peak and mean were obtained from both sides during the braking and propulsion phases. The dominant side was obtained for the braking and propulsion phase as the side with the largest peak or mean force and agreement was assessed using percentage agreement and the kappa coefficient. Braking phase peak and mean force methods demonstrated a percentage agreement of 84% and a kappa value of 0.67 (95% confidence limits: 0.45-0.90), indicating substantial agreement. Propulsion phase peak and mean force methods demonstrated a percentage agreement of 87% and a kappa value of 0.72 (95% confidence limits: 0.51-0.93), indicating substantial agreement. While agreement was substantial, side-to-side differences were not reflected equally when peak and mean force methods of assessing CMJ asymmetry were used. These methods should not be used interchangeably, but rather a combined approach should be used where practitioners consider both peak and mean force to obtain the fullest picture of athlete asymmetry.

Advanced emergency braking controller design for pedestrian protection oriented automotive collision avoidance system.

PubMed

Lie, Guo; Zejian, Ren; Pingshu, Ge; Jing, Chang

2014-01-01

Automotive collision avoidance system, which aims to enhance the active safety of the vehicle, has become a hot research topic in recent years. However, most of the current systems ignore the active protection of pedestrian and other vulnerable groups in the transportation system. An advanced emergency braking control system is studied by taking into account the pedestrians and the vehicles. Three typical braking scenarios are defined and the safety situations are assessed by comparing the current distance between the host vehicle and the obstacle with the critical braking distance. To reflect the nonlinear time-varying characteristics and control effect of the longitudinal dynamics, the vehicle longitudinal dynamics model is established in CarSim. Then the braking controller with the structure of upper and lower layers is designed based on sliding mode control and the single neuron PID control when confronting deceleration or emergency braking conditions. Cosimulations utilizing CarSim and Simulink are finally carried out on a CarSim intelligent vehicle model to explore the effectiveness of the proposed controller. Results display that the designed controller has a good response in preventing colliding with the front vehicle or pedestrian.

Advanced Emergency Braking Controller Design for Pedestrian Protection Oriented Automotive Collision Avoidance System

PubMed Central

Lie, Guo; Zejian, Ren; Pingshu, Ge; Jing, Chang

2014-01-01

Automotive collision avoidance system, which aims to enhance the active safety of the vehicle, has become a hot research topic in recent years. However, most of the current systems ignore the active protection of pedestrian and other vulnerable groups in the transportation system. An advanced emergency braking control system is studied by taking into account the pedestrians and the vehicles. Three typical braking scenarios are defined and the safety situations are assessed by comparing the current distance between the host vehicle and the obstacle with the critical braking distance. To reflect the nonlinear time-varying characteristics and control effect of the longitudinal dynamics, the vehicle longitudinal dynamics model is established in CarSim. Then the braking controller with the structure of upper and lower layers is designed based on sliding mode control and the single neuron PID control when confronting deceleration or emergency braking conditions. Cosimulations utilizing CarSim and Simulink are finally carried out on a CarSim intelligent vehicle model to explore the effectiveness of the proposed controller. Results display that the designed controller has a good response in preventing colliding with the front vehicle or pedestrian. PMID:25097870

Braking due to non-resonant magnetic perturbations and comparison with neoclassical toroidal viscosity torque in EXTRAP T2R

NASA Astrophysics Data System (ADS)

Frassinetti, L.; Sun, Y.; Fridström, R.; Menmuir, S.; Olofsson, K. E. J.; Brunsell, P. R.; Khan, M. W. M.; Liang, Y.; Drake, J. R.

2015-09-01

The non-resonant magnetic perturbation (MP) braking is studied in the EXTRAP T2R reversed-field pinch (RFP) and the experimental braking torque is compared with the torque expected by the neoclassical toroidal viscosity (NTV) theory. The EXTRAP T2R active coils can apply magnetic perturbations with a single harmonic, either resonant or non-resonant. The non-resonant MP produces velocity braking with an experimental torque that affects a large part of the core region. The experimental torque is clearly related to the plasma displacement, consistent with a quadratic dependence as expected by the NTV theory. The work show a good qualitative agreement between the experimental torque in a RFP machine and NTV torque concerning both the torque density radial profile and the dependence on the non-resonant MP harmonic.

Brake reactions of distracted drivers to pedestrian Forward Collision Warning systems.

PubMed

Lubbe, Nils

2017-06-01

Forward Collision Warning (FCW) can be effective in directing driver attention towards a conflict and thereby aid in preventing or mitigating collisions. FCW systems aiming at pedestrian protection have been introduced onto the market, yet an assessment of their safety benefits depends on the accurate modeling of driver reactions when the system is activated. This study contributes by quantifying brake reaction time and brake behavior (deceleration levels and jerk) to compare the effectiveness of an audio-visual warning only, an added haptic brake pulse warning, and an added Head-Up Display in reducing the frequency of collisions with pedestrians. Further, this study provides a detailed data set suited for the design of assessment methods for car-to-pedestrian FCW systems. Brake response characteristics were measured for heavily distracted drivers who were subjected to a single FCW event in a high-fidelity driving simulator. The drivers maintained a self-regulated speed of 30km/h in an urban area, with gaze direction diverted from the forward roadway by a secondary task. Collision rates and brake reaction times differed significantly across FCW settings. Brake pulse warnings resulted in the lowest number of collisions and the shortest brake reaction times (mean 0.8s, SD 0.29s). Brake jerk and deceleration were independent of warning type. Ninety percent of drivers exceeded a maximum deceleration of 3.6m/s 2 and a jerk of 5.3m/s 3 . Brake pulse warning was the most effective FCW interface for preventing collisions. In addition, this study presents the data required for driver modeling for car-to-pedestrian FCW similar to Euro NCAP's 2015 car-to-car FCW assessment. Practical applications: Vehicle manufacturers should consider the introduction of brake pulse warnings to their FCW systems. Euro NCAP could introduce an assessment that quantifies the safety benefits of pedestrian FCW systems and thereby aid the proliferation of effective systems. Copyright © 2017 National Safety Council and Elsevier Ltd. All rights reserved.

A NEW, LOW BRAKING INDEX FOR THE LMC PULSAR B0540–69

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

Marshall, F. E.; Harding, A. K.; Guillemot, L.

2016-08-20

We report the results of a 16 month monitoring campaign using the Swift satellite of PSR B0540–69, a young pulsar in the Large Magellanic Cloud. Phase connection was maintained throughout the campaign so that a reliable ephemeris could be determined, and the length of the campaign is adequate to accurately determine the spin frequency ν and its first and second derivatives. The braking index n is 0.031 ± 0.013 (90% confidence), a value much lower than previously reported for B0540–69 and almost all other young pulsars. We use data from the extensive monitoring campaign with Rossi X-ray Timing Explorer tomore » show that timing noise is unlikely to significantly affect the measurement. This is the first measurement of the braking index in the pulsar's recently discovered high spin-down state. We discuss possible mechanisms for producing the low braking index.« less

Kinetic Determinants of Reactive Strength in Highly Trained Sprint Athletes.

PubMed

Douglas, Jamie; Pearson, Simon; Ross, Angus; McGuigan, Mike

2018-06-01

Douglas, J, Pearson, S, Ross, A, and McGuigan, M. Kinetic determinants of reactive strength in highly trained sprint athletes. J Strength Cond Res 32(6): 1562-1570, 2018-The purpose of this study was to determine the braking and propulsive phase kinetic variables underpinning reactive strength in highly trained sprint athletes in comparison with a nonsprint-trained control group. Twelve highly trained sprint athletes and 12 nonsprint-trained participants performed drop jumps (DJs) from 0.25, 0.50, and 0.75 m onto a force plate. One familiarization session was followed by an experimental testing session within the same week. Reactive strength index (RSI), contact time, flight time, and leg stiffness were determined. Kinetic variables including force, power, and impulse were assessed within the braking and propulsive phases. Sprint-trained athletes demonstrated higher RSI vs. nonsprint-trained participants across all drop heights {3.02 vs. 2.02; ES (±90% confidence limit [CL]): 3.11 ± 0.86}. This difference was primarily attained by briefer contact times (0.16 vs. 0.22 seconds; effect size [ES]: -1.49 ± 0.53) with smaller differences observed for flight time (0.50 vs. 0.46 seconds; ES: 0.53 ± 0.58). Leg stiffness, braking and propulsive phase force, and power were higher in sprint-trained athletes. Very large differences were observed in mean braking force (51 vs. 38 N·kg; ES: 2.57 ± 0.73) which was closely associated with contact time (r ±90% CL: -0.93 ± 0.05). Sprint-trained athletes exhibited superior reactive strength than nonsprint-trained participants. This was due to the ability to strike the ground with a stiffer leg spring, an enhanced expression of braking force, and possibly an increased utilization of elastic structures. The DJ kinetic analysis provides additional insight into the determinants of reactive strength which may inform subsequent testing and training.

Force-Time Characteristics and Running Velocity of Male Sprinters During the Acceleration Phase of Sprinting.

ERIC Educational Resources Information Center

Mero, Antti

1988-01-01

Investigation of the force-time characteristics of eight male sprinters during the acceleration phase of the sprint start suggested that the braking and propulsion phases occur immediately after the block phase and that muscle strength strongly affects running velocity in the sprint start. (Author/CB)

Design and fabrication of advanced materials from Illinois coal wastes. Quarterly report, 1 March 1995--31 May 1995

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

Malhotra, V.M.; Wright, M.A.

1995-12-31

The main goal of this project is to develop a bench-scale procedure to design and fabricate advanced brake and structural composite materials from Illinois coal combustion residues. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), differential thermal analysis (DTA), and transmission-Fourier transform infrared (FTIR) were conducted on PCC fly ash (Baldwin), FBC fly ash (ADM unit1-6), FBC fly ash (S.I. coal), FBC spent bed ash (ADM unit1-6), bottom ash, and scrubber sludge (CWLP) residues to characterize their geometrical shapes, mineral phases, and thermal stability. Our spectroscopic results indicate that the scrubber sludge is mainly composed of a gypsum-like phase whosemore » lattice structure is different from the lattice structure of conventional gypsum, and sludge does not contain hannebachite (CaSO{sub 3}0.5H{sub 2}O) phase. In the second and third quarters the focus of research has been on developing protocols for the formation of advanced brake composites and structural composites. Our attempts to fabricate brake frictional shoes, in the form of 1.25 inch disks, from PCC fly ash, FBC spent bed ash, scrubber sludge, coal char, iron particles, and coal tar were successful. Based on the experience gained and microscopic analyses, we have now upscaled our procedures to fabricate 2.5 inch diameter disks from coal combustion residues. The SEM and Young`s modulus analyses of brake composites fabricated at 400 psi < Pressure < 2200 psi suggest pressure has a strong influence on the particle packing and the filling of interstices in our composites.« less

Fatal crashes of passenger vehicles before and after adding antilock braking systems.

PubMed

Farmer, C M; Lund, A K; Trempel, R E; Braver, E R

1997-11-01

Fatal crash rates of passenger cars and vans were compared for the last model year before four-wheel antilock brakes were introduced and the first model year for which antilock brakes were standard equipment. Vehicles selected for analysis had no other significant design changes between the model years being compared, and the model years with and without antilocks were no more than two years apart. The overall fatal crash rates were similar for the two model years. However, the vehicles with antilocks were significantly more likely to be involved in crashes fatal to their own occupants, particularly single-vehicle crashes. Conversely, antilock vehicles were less likely to be involved in crashes fatal to occupants of other vehicles or nonoccupants (pedestrians, bicyclists). Overall, antilock brakes appear to have had little effect on fatal crash involvement. Further study is needed to better understand why fatality risk has increased for occupants of antilock vehicles.

The collision forces and lower-extremity inter-joint coordination during running.

PubMed

Wang, Li-I; Gu, Chin-Yi; Wang, I-Lin; Siao, Sheng-Wun; Chen, Szu-Ting

2018-06-01

The purpose of this study was to compare the lower extremity inter-joint coordination of different collision forces runners during running braking phase. A dynamical system approach was used to analyse the inter-joint coordination parameters. Data were collected with six infra-red cameras and two force plates. According to the impact peak of the vertical ground reaction force, twenty habitually rearfoot-strike runners were categorised into three groups: high collision forces runners (HF group, n = 8), medium collision forces runners (MF group, n = 5), and low collision forces runners (LF group, n = 7). There were no significant differences among the three groups in the ankle and knee joint angle upon landing and in the running velocity (p > 0.05). The HF group produced significantly smaller deviation phase (DP) of the hip flexion/extension-knee flexion/extension during the braking phase compared with the MF and LF groups (p < 0.05). The DP of the hip flexion/extension-knee flexion/extension during the braking phase correlated negatively with the collision force (p < 0.05). The disparities regarding the flexibility of lower extremity inter-joint coordination were found in high collision forces runners. The efforts of the inter-joint coordination and the risk of running injuries need to be clarified further.

Initial comparison of single cylinder Stirling engine computer model predictions with test results

NASA Technical Reports Server (NTRS)

Tew, R. C., Jr.; Thieme, L. G.; Miao, D.

1979-01-01

A NASA developed digital computer code for a Stirling engine, modelling the performance of a single cylinder rhombic drive ground performance unit (GPU), is presented and its predictions are compared to test results. The GPU engine incorporates eight regenerator/cooler units and the engine working space is modelled by thirteen control volumes. The model calculates indicated power and efficiency for a given engine speed, mean pressure, heater and expansion space metal temperatures and cooler water inlet temperature and flow rate. Comparison of predicted and observed powers implies that the reference pressure drop calculations underestimate actual pressure drop, possibly due to oil contamination in the regenerator/cooler units, methane contamination in the working gas or the underestimation of mechanical loss. For a working gas of hydrogen, the predicted values of brake power are from 0 to 6% higher than experimental values, and brake efficiency is 6 to 16% higher, while for helium the predicted brake power and efficiency are 2 to 15% higher than the experimental.

Traffic flow behavior at a single-lane urban roundabout

NASA Astrophysics Data System (ADS)

Lakouari, N.; Oubram, O.; Ez-Zahraouy, H.; Cisneros-Villalobos, L.; Velásquez-Aguilar, J. G.

In this paper, we propose a stochastic cellular automata model to study the traffic behavior at a single-lane roundabout. Vehicles can enter the interior lane or exit from it via N intersecting lane, the boundary conditions are stochastic. The traffic is controlled by a self-organized scheme. It has turned out that depending on the rules of insertion to the roundabout, five distinct traffic phases can appear, namely, free flow, congestion, maximum current, jammed and gridlock. The transition between the free flow and the gridlock is forbidden. The density profiles are used to study the traffic pattern at the interior lane of the roundabout. In order to quantify the interactions between vehicles in the interior lane of the roundabout, the velocity correlation coefficient (VCC) is also studied. Besides, the spatiotemporal diagrams corresponding to the entry/exit lanes are derived numerically. Furthermore, we have investigated the effect of displaying signal (PIn), as the PIn decreases, the maximum current increases at the expense of the free flow and the jamming phase. Finally, we have investigated the effect of the braking probability P on the interior lane of the roundabout. We have found that the increase of P raises the spontaneous jam formation on the ring. Thus, enlarges the maximum current and the jamming phase while the free flow phase decreases.

Correlation between crash avoidance maneuvers and injury severity sustained by motorcyclists in single-vehicle crashes.

PubMed

Wang, Chen; Lu, Linjun; Lu, Jian; Wang, Tao

2016-01-01

In order to improve motorcycle safety, this article examines the correlation between crash avoidance maneuvers and injury severity sustained by motorcyclists, under multiple precrash conditions. Ten-year crash data for single-vehicle motorcycle crashes from the General Estimates Systems (GES) were analyzed, using partial proportional odds models (i.e., generalized ordered logit models). The modeling results show that "braking (no lock-up)" is associated with a higher probability of increased severity, whereas "braking (lock-up)" is associated with a higher probability of decreased severity, under all precrash conditions. "Steering" is associated with a higher probability of reduced injury severity when other vehicles are encroaching, whereas it is correlated with high injury severity under other conditions. "Braking and steering" is significantly associated with a higher probability of low severity under "animal encounter and object presence," whereas it is surprisingly correlated with high injury severity when motorcycles are traveling off the edge of the road. The results also show that a large number of motorcyclists did not perform any crash avoidance maneuvers or conducted crash avoidance maneuvers that are significantly associated with high injury severity. In general, this study suggests that precrash maneuvers are an important factor associated with motorcyclists' injury severity. To improve motorcycle safety, training/educational programs should be considered to improve safety awareness and adjust driving habits of motorcyclists. Antilock brakes and such systems are also promising, because they could effectively prevent brake lock-up and assist motorcyclists in maneuvering during critical conditions. This study also provides valuable information for the design of motorcycle training curriculum.

Deployable Engine Air Brake

NASA Technical Reports Server (NTRS)

2014-01-01

On approach, next-generation aircraft are likely to have airframe noise levels that are comparable to or in excess of engine noise. ATA Engineering, Inc. (ATA) is developing a novel quiet engine air brake (EAB), a device that generates "equivalent drag" within the engine through stream thrust reduction by creating a swirling outflow in the turbofan exhaust nozzle. Two Phase II projects were conducted to mature this technology: (1) a concept development program (CDP) and (2) a system development program (SDP).

Personal exposures to asbestos fibers during brake maintenance of passenger vehicles.

PubMed

Cely-García, María Fernanda; Sánchez, Mauricio; Breysse, Patrick N; Ramos-Bonilla, Juan P

2012-11-01

Brake linings and brake pads are among the asbestos-containing products that are readily available in Colombia. When sold separated from their support, brake linings require extensive manipulation involving several steps that include drilling, countersinking, riveting, bonding, cutting, beveling, and grinding. Without this manipulation, brake linings cannot be installed in a vehicle. The manipulation process may release asbestos fibers, which may expose brake mechanics to the fibers. Three brake repair shops located in Bogotá (Colombia) were sampled for 3 or 4 consecutive days using US National Institute for Occupational Safety and Health (NIOSH) methods 7400 and 7402. Standard procedures for quality control were followed during the sampling process, and asbestos samples were analyzed by an American Industrial Hygiene Association accredited laboratory. Personal samples were collected to assess full-shift and short-term exposures. Area samples were also collected close to the brake-lining manipulation equipment and within office facilities. Activities were documented during the sampling process. Using Phase Contrast Microscopy Equivalent counts to estimate air asbestos concentrations, all personal samples [i.e. 8-h time-weighted averages (TWAs) and 30-min personal samples] were in compliance with the US Occupational Safety and Health Administration standards. Personal asbestos concentrations based on transmission electron microscopy counts were extremely high, ranging from 0.006 to 3.493 f cm(-3) for 8-h TWA and from 0.015 to 8.835 f cm(-3) for 30-min samples. All asbestos fibers detected were chrysotile. Cleaning facilities and grinding linings resulted in the highest asbestos exposures based on transmission electron microscopy counts. There were also some samples that did not comply with the NIOSH's recommended exposure limits. The results indicate that the brake mechanics sampled are exposed to extremely high asbestos concentrations (i.e. based on transmission electron microscopy counts), suggesting that this occupational group could be at excess risk of asbestos-related diseases.

Motor programmes for the termination of gait in humans: organisation and velocity-dependent adaptation

PubMed Central

Crenna, Paolo; Cuong, Do Manh; Brénière, Yvon

2001-01-01

The organisation of the muscular activities responsible for the termination of gait, their modulation as a function of the rate of progression and the associated mechanical effects were investigated in normal adults, using EMG, force plate and kinematic recordings. In particular, the braking actions in reaction to a visual cue presented at the instant of heel-strike were analysed quantitatively, with a focus on representative leg and thigh muscles of the weight-supporting (stance) and oscillating (swing) limb, during walk-and-stop trials performed at three different velocities. In the stance limb, the EMG associated with braking started approximately 150 ms after the stop signal and, on average, displayed a distal-to-proximal activation sequence that primarily involved the posterior muscle groups (soleus, SOL, and hamstring, HAM). With the exception of SOL, which showed a single EMG burst, EMG patterns consisted of two or three progressively larger components occurring reciprocally in antagonistic muscles. Increasing walking speed yielded a significant reduction of the activity in distal muscles, and a simultaneous increment in proximal muscles. The mechanical effect of the earlier braking actions, estimated from the backward-directed wave of the horizontal ground reaction force, decreased in a velocity-dependent manner. In the swing limb the braking activities began approximately 330 ms after the stop signal and, on average, revealed a proximal-to-distal activation sequence with the extensor groups (quadriceps, QUAD, and SOL) playing a prominent role. They always consisted of single EMG bursts, largely co-activated in the antagonist muscles. The onset latencies of the individual components showed a close correlation, and the spatio-temporal parameters were always scaled in parallel. Unlike the stance limb, the mechanical braking action associated with the final contact of the swing limb increased with walking speed. The results indicate that the muscle synergies responsible for the rapid termination of gait in response to a ground-contact visual cue are produced by a relatively flexible set of motor commands modulated according to different velocity-dependent strategies in the weight-bearing limb, and by a single, fairly robust motor programme in the swing limb. Mechanical constraints related to the relative position of the centre of foot pressure and centre of body mass at the time the braking commands begin to affect external forces, may condition the difference between the two sides of the body. PMID:11744777

Optimal impulsive manoeuvres and aerodynamic braking

NASA Technical Reports Server (NTRS)

Jezewski, D. J.

1985-01-01

A method developed for obtaining solutions to the aerodynamic braking problem, using impulses in the exoatmospheric phases is discussed. The solution combines primer vector theory and the results of a suboptimal atmospheric guidance program. For a specified initial and final orbit, the solution determines: (1) the minimum impulsive cost using a maximum of four impulses, (2) the optimal atmospheric entry and exit-state vectors subject to equality and inequality constraints, and (3) the optimal coast times. Numerical solutions which illustrate the characteristics of the solution are presented.

Decoupled recovery of energy and momentum with correction of n = 2 error fields

DOE PAGES

Paz-Soldan, Carlos A.; Logan, Nikolas C.; Lanctot, Matthew J.; ...

2015-07-06

Experiments applying known n = 2 “proxy” error fields (EFs) find that the rotation braking introduced by the proxy EF cannot be completely alleviated through optimal n = 2 correction with poorly matched poloidal spectra. This imperfect performance recovery demonstrates the importance of correcting multiple components of the n = 2 field spectrum and is in contrast to previous results with n = 1 EFs despite similar execution. Measured optimal n = 2 proxy EF correction currents are consistent with those required to null dominant mode coupling to the resonant surfaces and minimize the neoclassical toroidal viscosity (NTV) torque, calculatedmore » using ideal MHD plasma response computation. Unlike rotation braking, density pumpout can be fully corrected despite poorly matched spectra, indicating density pumpout is driven only by a single component proportional to the resonant coupling. Through precise n = 2 spectral control density pumpout and rotation braking can thus be decoupled. Rotation braking with n = 2 fields is also found to be proportional to the level of concurrent toroidal rotation, consistent with NTV theory. Lastly, plasmas with modest countercurrent rotation are insensitive to the n = 2 field with neither rotation braking nor density pumpout observed.« less

EEG alpha spindles and prolonged brake reaction times during auditory distraction in an on-road driving study.

PubMed

Sonnleitner, Andreas; Treder, Matthias Sebastian; Simon, Michael; Willmann, Sven; Ewald, Arne; Buchner, Axel; Schrauf, Michael

2014-01-01

Driver distraction is responsible for a substantial number of traffic accidents. This paper describes the impact of an auditory secondary task on drivers' mental states during a primary driving task. N=20 participants performed the test procedure in a car following task with repeated forced braking on a non-public test track. Performance measures (provoked reaction time to brake lights) and brain activity (EEG alpha spindles) were analyzed to describe distracted drivers. Further, a classification approach was used to investigate whether alpha spindles can predict drivers' mental states. Results show that reaction times and alpha spindle rate increased with time-on-task. Moreover, brake reaction times and alpha spindle rate were significantly higher while driving with auditory secondary task opposed to driving only. In single-trial classification, a combination of spindle parameters yielded a median classification error of about 8% in discriminating the distracted from the alert driving. Reduced driving performance (i.e., prolonged brake reaction times) during increased cognitive load is assumed to be indicated by EEG alpha spindles, enabling the quantification of driver distraction in experiments on public roads without verbally assessing the drivers' mental states. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mitigating the effects of in-vehicle distractions through use of the Psychological Refractory Period paradigm.

PubMed

Hibberd, Daryl L; Jamson, Samantha L; Carsten, Oliver M J

2013-01-01

Modern driving involves frequent and potentially detrimental interactions with distracting in-vehicle tasks. Distraction has been shown to slow brake reaction time and decrease lateral and longitudinal vehicle control. It is likely that these negative effects will become more prevalent in the future as advances are made in the functionality, availability, and number of in-vehicle systems. This paper addresses this problem by considering ways to manage in-vehicle task presentation to mitigate their distracting effects. A driving simulator experiment using 48 participants was performed to investigate the existence of the Psychological Refractory Period in the driving context and its effect on braking performance. Drivers were exposed to lead vehicle braking events in isolation (single-task) and with a preceding surrogate in-vehicle task (dual-task). In dual-task scenarios, the time interval between the in-vehicle and braking tasks was manipulated. Brake reaction time increased when drivers were distracted. The in-vehicle task interfered with the performance of the braking task in a manner that was dependent on the interval between the two tasks, with slower reactions following a shorter inter-task interval. This is the Psychological Refractory Period effect. These results have implications for driver safety during in-vehicle distraction. The findings are used to develop recommendations regarding the timing of in-vehicle task presentation so as to reduce their potentially damaging effects on braking performance. In future, these guidelines could be incorporated into a driver workload management system to minimise the opportunity for a driver to be distracted from the ongoing driving task. Copyright © 2012 Elsevier Ltd. All rights reserved.

St. Fergus terminal gets turboexpanders for critical service

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

Lillard, J.K.; Nicol, G.

1994-09-05

To expand the St. Fergus gas-reception terminal for the Scottish Area Gas Evacuation (SAGE) system, Mobil North Sea Ltd. is adding a second separation train and two treatment trains. To meet pipeline-gas specifications over a wide range of low rates and feed-gas compositions, single-stage turboexpander chilling was selected over Joule-Thomson valve expansion. Four turboexpanders (two per process train) will operate in parallel to achieve the required performance over the entire flow range of 90--575 MMscfd per process train. Unusual operating conditions for the turboexpanders include dense-phase inlet gas, expansion near the cricondenbar, and high equilibrium liquid content at the exhaustmore » (up to 50 wt %). The two turboexpanders in each train share common suction and discharge facilities as do their associated brake compressor. Details of the more than 400 million pounds Sterling Phase B discussed here include commissioning, start-up, and operation.« less

Loading and performance of the support leg in kicking.

PubMed

Ball, Kevin

2013-09-01

The punt kick is important in many football codes and support leg kinematics and ground reaction forces have been implicated in injury and performance in kicking. To evaluate ground reaction forces and support leg kinematics in the punt kick. Cross sectional study. Seven elite Australian football players performed maximal kicks into a net using both the preferred and non-preferred legs. A force plate measured ground reaction forces and an optical motion capture system (200Hz) collected kinematic data during the stance phase of the kick. Preferred and non-preferred legs were compared and performance was evaluated by correlating parameters with foot speed at ball contact. Vertical forces were larger than running at a similar speed but did not reach levels that might be considered an injury risk. Braking forces were directed solely posteriorly, as for soccer kicks, but lateral force patterns varied with some players experiencing greater forces medially and others laterally. A more extended support leg, larger peak vertical and braking force during the stance phase and a shorter stance contact time was associated with larger kick leg foot speed at ball contact. No difference existed between the preferred and non-preferred legs for ground reaction forces or support leg mechanics. To punt kick longer, a straighter support leg, less time on the ground and stronger braking should be encouraged. Conditioning the support leg to provide stronger braking potential is recommended. Copyright © 2012 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

Single rotating stars and the formation of bipolar planetary nebula

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

García-Segura, G.; Villaver, E.; Langer, N.

2014-03-10

We have computed new stellar evolution models that include the effects of rotation and magnetic torques under different hypotheses. The goal is to test whether a single star can sustain the rotational velocities needed in the envelope for magnetohydrodynamical(MHD) simulations to shape bipolar planetary nebulae (PNe) when high mass-loss rates take place. Stellar evolution models with main sequence masses of 2.5 and 5 M {sub ☉} and initial rotational velocities of 250 km s{sup –1} have been followed through the PNe formation phase. We find that stellar cores have to be spun down using magnetic torques in order to reproducemore » the rotation rates observed for white dwarfs. During the asymptotic giant branch phase and beyond, the magnetic braking of the core has a practically null effect on increasing the rotational velocity of the envelope since the stellar angular momentum is efficiently removed by the wind. We have also tested the best possible case scenarios in rather non-physical contexts to give enough angular momentum to the envelope. We find that we cannot get the envelope of a single star to rotate at the speeds needed for MHD simulations to form bipolar PNe. We conclude that single stellar rotators are unlikely to be the progenitors of bipolar PNe under the current MHD model paradigm.« less

Test and Evaluation of an Eddy Current Clutch/Brake Propulsion System

DOT National Transportation Integrated Search

1975-01-01

This report covers the Phase II effort of a program to develop and test a 15 hp eddy-current clutch propulsion system. Included in the Phase 2 effort are the test and evaluation of the eddy-current clutch propulsion system on board a test vehicle. Th...

Calmodulin regulates Cav3 T-type channels at their gating brake

PubMed Central

Taiakina, Valentina; Monteil, Arnaud; Piazza, Michael; Guan, Wendy; Stephens, Robert F.; Dieckmann, Thorsten; Guillemette, Joseph Guy; Spafford, J. David

2017-01-01

Calcium (Cav1 and Cav2) and sodium channels possess homologous CaM-binding motifs, known as IQ motifs in their C termini, which associate with calmodulin (CaM), a universal calcium sensor. Cav3 T-type channels, which serve as pacemakers of the mammalian brain and heart, lack a C-terminal IQ motif. We illustrate that T-type channels associate with CaM using co-immunoprecipitation experiments and single particle cryo-electron microscopy. We demonstrate that protostome invertebrate (LCav3) and human Cav3.1, Cav3.2, and Cav3.3 T-type channels specifically associate with CaM at helix 2 of the gating brake in the I–II linker of the channels. Isothermal titration calorimetry results revealed that the gating brake and CaM bind each other with high-nanomolar affinity. We show that the gating brake assumes a helical conformation upon binding CaM, with associated conformational changes to both CaM lobes as indicated by amide chemical shifts of the amino acids of CaM in 1H-15N HSQC NMR spectra. Intact Ca2+-binding sites on CaM and an intact gating brake sequence (first 39 amino acids of the I–II linker) were required in Cav3.2 channels to prevent the runaway gating phenotype, a hyperpolarizing shift in voltage sensitivities and faster gating kinetics. We conclude that the presence of high-nanomolar affinity binding sites for CaM at its universal gating brake and its unique form of regulation via the tuning of the voltage range of activity could influence the participation of Cav3 T-type channels in heart and brain rhythms. Our findings may have implications for arrhythmia disorders arising from mutations in the gating brake or CaM. PMID:28972185

49 CFR 232.309 - Equipment and devices used to perform single car air brake tests.

Code of Federal Regulations, 2010 CFR

2010-10-01

... least once each calendar day of use. (b) Except for single car test devices, mechanical test devices such as pressure gauges, flow meters, orifices, etc. shall be calibrated once every 92 days. (c) Electronic test devices shall be calibrated at least once every 365 days. (d) Test equipment and single car...

High voltage bus and auxiliary heater control system for an electric or hybrid vehicle

DOEpatents

Murty, Balarama Vempaty

2000-01-01

A control system for an electric or hybrid electric vehicle includes a vehicle system controller and a control circuit having an electric immersion heater. The heater is electrically connected to the vehicle's high voltage bus and is thermally coupled to a coolant loop containing a heater core for the vehicle's climate control system. The system controller responds to cabin heat requests from the climate control system by generating a pulse width modulated signal that is used by the control circuit to operate the heater at a duty cycle appropriate for the amount of cabin heating requested. The control system also uses the heater to dissipate excess energy produced by an auxiliary power unit and to provide electric braking when regenerative braking is not desirable and manual braking is not necessary. The control system further utilizes the heater to provide a safe discharge of a bank of energy storage capacitors following disconnection of the battery or one of the high voltage connectors used to transmit high voltage operating power to the various vehicle systems. The control circuit includes a high voltage clamping circuit that monitors the voltage on the bus and operates the heater to clamp down the bus voltage when it exceeds a pre-selected maximum voltage. The control system can also be used to phase in operation of the heater when the bus voltage exceeds a lower threshold voltage and can be used to phase out the auxiliary power unit charging and regenerative braking when the battery becomes fully charged.

Dynamic Braking System of a Tidal Generator: Preprint

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

Muljadi, Eduard; Wright, Alan; Gevorgian, Vahan

Renewable energy generation has experienced significant cost reductions during the past decades, and it has become more accepted by the global population. In the beginning, wind generation dominated the development and deployment of renewable energy; however, during recent decades, photovoltaic (PV) generation has grown at a very significant pace due to the tremendous decrease in the cost of PV modules. The focus on renewable energy generation has now expanded to include new types with promising future applications, such as river and tidal generation. The input water flow to these types of resources is more predictable than wind or solar generation.more » The data used in this paper is representative of a typical river or tidal generator. The analysis is based on a generator with a power rating of 40 kW. The tidal generator under consideration is driven by two sets of helical turbines connected to each side of the generator located in between the turbines. The generator is operated in variable speed, and it is controlled to maximize the energy harvested as well as the operation of the turbine generator. The electrical system consists of a three-phase permanent magnet generator connected to a three-phase passive rectifier. The output of the rectifier is connected to a DC-DC converter to match the rectifier output to the DC bus voltage of the DC-AC inverter. The three-phase inverter is connected to the grid, and it is controlled to provide a good interface with the grid. One important aspect of river and tidal generation is the braking mechanism. In a tidal generator, the braking mechanism is important to avoid a runaway condition in case the connection to the grid is lost when there is a fault in the lines. A runaway condition may lead to an overspeed condition and cause extreme stresses on the turbine blade structure and eventual disintegration of the mechanical structure. In this paper, the concept of the dynamic braking system is developed and investigated for normal and abnormal operations. The main objective is to optimize the performance under emergency braking while designing the system to be as simple as possible to avoid overdesigning the power electronics or exceeding the target budget.« less

Optimized coordination of brakes and active steering for a 4WS passenger car.

PubMed

Tavasoli, Ali; Naraghi, Mahyar; Shakeri, Heman

2012-09-01

Optimum coordination of individual brakes and front/rear steering subsystems is presented. The integrated control strategy consists of three modules. A coordinated high-level control determines the body forces/moment required to achieve vehicle motion objectives. The body forces/moment are allocated to braking and steering subsystems through an intermediate unit, which integrates available subsystems based on phase plane notion in an optimal manner. To this end, an optimization problem including several equality and inequality constraints is defined and solved analytically, such that a real-time implementation can be realized without the use of numeric optimization software. A low-level slip-ratio controller works to generate the desired longitudinal forces at small longitudinal slip-ratios, while averting wheel locking at large slip-ratios. The efficiency of the suggested approach is demonstrated through computer simulations. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

An introduction to shuttle/LDEF retrieval operations: The R-bar approach option. [orbital mechanics and braking schedule

NASA Technical Reports Server (NTRS)

Hall, W. M.

1978-01-01

Simulated orbiter direct approaches during long duration exposure facility (LDEF) retrieval operations reveal that the resultant orbiter jet plume fields can significantly disturb LDEF. An alternate approach technique which utilizes orbital mechanics forces in lieu of jets to brake the final orbiter/LDEF relative motion during the final approach, is described. Topics discussed include: rendezvous operations from the terminal phase initiation burn through braking at some standoff distance from LDEF, pilot and copilot activities, the cockpit instrumentation employed, and a convenient coordinate frame for studying the relative motion between two orbiting bodies. The basic equations of motion for operating on the LDEF radius vector are introduced. Practical considerations of implementing an R-bar approach, namely, orbiter/LDEF relative state uncertainties and orbiter control system limitations are explored. A possible R-bar approach strategy is developed and demonstrated.

Influences of pre-crash braking induced dummy - forward displacements on dummy behaviour during EuroNCAP frontal crashtest.

PubMed

Woitsch, Gernot; Sinz, Wolfgang

2014-01-01

Combination of active and passive safety systems is a future key to further improvement in vehicle safety. Autonomous braking systems are able to reduce collision speeds, and therefore severity levels significantly. Passengers change their position due to pre-impact vehicle motion, a fact, which has not yet been considered in common crash tests. For this paper, finite elements simulations of crash tests were performed to show that forward displacements due to pre-crash braking do not necessarily increase dummy load levels. So the influence of different pre-crash scenarios, all leading to equal closing speeds in the crash phase, are considered in terms of vehicle motion (pitching, deceleration) and restraint system configurations (belt load limiter, pretensioner). The influence is evaluated by dummy loads as well as contact risk between the dummy and the interior. Copyright © 2013 Elsevier Ltd. All rights reserved.

Plasma Braking Due to External Magnetic Perturbations

NASA Astrophysics Data System (ADS)

Frassinetti, L.; Olofsson, Kejo; Brunsell, P. R.; Khan, M. W. M.; Drake, J. R.

2010-11-01

The RFP EXTRAP T2R is equipped with a comprehensive active feedback system (128 active saddle coils in the full-coverage array) and active control of both resonant and non-resonant MHD modes has been demonstrated. The feedback algorithms, based on modern control methodology such as reference mode tracking (both amplitude and phase), are a useful tool to improve the ``state of the art'' of the MHD mode control. But this tool can be used also to improve the understanding and the characterization of other phenomena such as the ELM mitigation with a resonant magnetic perturbation or the plasma viscosity. The present work studies plasma and mode braking due to static RMPs. Results show that a static RMP produces a global braking of the flow profile. The study of the effect of RMPs characterized by different helicities will also give information on the plasma viscosity profile. Experimental results are finally compared to theoretical models.

On Choosing a Rational Flight Trajectory to the Moon

NASA Astrophysics Data System (ADS)

Gordienko, E. S.; Khudorozhkov, P. A.

2017-12-01

The algorithm for choosing a trajectory of spacecraft flight to the Moon is discussed. The characteristic velocity values needed for correcting the flight trajectory and a braking maneuver are estimated using the Monte Carlo method. The profile of insertion and flight to a near-circular polar orbit with an altitude of 100 km of an artificial lunar satellite (ALS) is given. The case of two corrections applied during the flight and braking phases is considered. The flight to an ALS orbit is modeled in the geocentric geoequatorial nonrotating coordinate system with the influence of perturbations from the Earth, the Sun, and the Moon factored in. The characteristic correction costs corresponding to corrections performed at different time points are examined. Insertion phase errors, the errors of performing the needed corrections, and the errors of determining the flight trajectory parameters are taken into account.

Constrained optimal multi-phase lunar landing trajectory with minimum fuel consumption

NASA Astrophysics Data System (ADS)

Mathavaraj, S.; Pandiyan, R.; Padhi, R.

2017-12-01

A Legendre pseudo spectral philosophy based multi-phase constrained fuel-optimal trajectory design approach is presented in this paper. The objective here is to find an optimal approach to successfully guide a lunar lander from perilune (18km altitude) of a transfer orbit to a height of 100m over a specific landing site. After attaining 100m altitude, there is a mission critical re-targeting phase, which has very different objective (but is not critical for fuel optimization) and hence is not considered in this paper. The proposed approach takes into account various mission constraints in different phases from perilune to the landing site. These constraints include phase-1 ('braking with rough navigation') from 18km altitude to 7km altitude where navigation accuracy is poor, phase-2 ('attitude hold') to hold the lander attitude for 35sec for vision camera processing for obtaining navigation error, and phase-3 ('braking with precise navigation') from end of phase-2 to 100m altitude over the landing site, where navigation accuracy is good (due to vision camera navigation inputs). At the end of phase-1, there are constraints on position and attitude. In Phase-2, the attitude must be held throughout. At the end of phase-3, the constraints include accuracy in position, velocity as well as attitude orientation. The proposed optimal trajectory technique satisfies the mission constraints in each phase and provides an overall fuel-minimizing guidance command history.

Double acting stirling engine phase control

DOEpatents

Berchowitz, David M.

1983-01-01

A mechanical device for effecting a phase change between the expansion and compression volumes of a double-acting Stirling engine uses helical elements which produce opposite rotation of a pair of crankpins when a control rod is moved, so the phase between two pairs of pistons is changed by +.psi. and the phase between the other two pairs of pistons is changed by -.psi.. The phase can change beyond .psi.=90.degree. at which regenerative braking and then reversal of engine rotation occurs.

Controller for a High-Power, Brushless dc Motor

NASA Technical Reports Server (NTRS)

Fleming, David J.; Makdad, Terence A.

1987-01-01

Driving and braking torques controllable. Control circuit operates 7-kW, 45-lb-ft (61-N-m), three-phase, brushless dc motor in both motor and generator modes. In motor modes, energy from power source is pulse-width modulated to motor through modified "H-bridge" circuit, in generator mode, energy from motor is pulse-width modulated into bank of load resistors to provide variable braking torques. Circuit provides high-resolution torque control in both directions over wide range of speeds and torques. Tested successfully at bus voltages up to 200 Vdc and currents up to 45 A.

A novel technique for optimal integration of active steering and differential braking with estimation to improve vehicle directional stability.

PubMed

Mirzaeinejad, Hossein; Mirzaei, Mehdi; Rafatnia, Sadra

2018-06-11

This study deals with the enhancement of directional stability of vehicle which turns with high speeds on various road conditions using integrated active steering and differential braking systems. In this respect, the minimum usage of intentional asymmetric braking force to compensate the drawbacks of active steering control with small reduction of vehicle longitudinal speed is desired. To this aim, a new optimal multivariable controller is analytically developed for integrated steering and braking systems based on the prediction of vehicle nonlinear responses. A fuzzy programming extracted from the nonlinear phase plane analysis is also used for managing the two control inputs in various driving conditions. With the proposed fuzzy programming, the weight factors of the control inputs are automatically tuned and softly changed. In order to simulate a real-world control system, some required information about the system states and parameters which cannot be directly measured, are estimated using the Unscented Kalman Filter (UKF). Finally, simulations studies are carried out using a validated vehicle model to show the effectiveness of the proposed integrated control system in the presence of model uncertainties and estimation errors. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Dancers with achilles tendinopathy demonstrate altered lower extremity takeoff kinematics.

PubMed

Kulig, Kornelia; Loudon, Janice K; Popovich, John M; Pollard, Christine D; Winder, Brooke R

2011-08-01

Controlled laboratory study using a cross-sectional design. To analyze lower extremity kinematics during takeoff of a "saut de chat" (leap) in dancers with and without a history of Achilles tendinopathy (AT). We hypothesized that dancers with AT would demonstrate different kinematic strategies compared to dancers without pathology, and that these differences would be prominent in the transverse and frontal planes. AT is a common injury experienced by dancers. Dance leaps such as the saut de chat place a large demand on the Achilles tendon. Sixteen female dancers with and without a history of AT (mean ± SD age, 18.8 ± 1.2 years) participated. Three-dimensional kinematics at the hip, knee, and ankle were quantified for the takeoff of the saut de chat, using a motion analysis system. A force platform was used to determine braking and push-off phases of takeoff. Peak sagittal, frontal, and transverse plane joint positions during the braking and push-off phases of the takeoff were examined statistically. Independent samples t tests were used to evaluate group differences (α = .05). The dancers in the tendinopathy group demonstrated significantly higher peak hip adduction during the braking phase of takeoff (mean ± SD, 13.5° ± 6.1° versus 7.7° ± 4.2°; P = .046). During the push-off phase, dancers with AT demonstrated significantly more internal rotation at the knee (13.2° ± 5.2° versus 6.9° ± 4.9°; P = .024). Dancers with AT demonstrate increased peak transverse and frontal plane kinematics when performing the takeoff of a saut de chat. These larger displacements may be either causative or compensatory factors in the development of AT.

Definition of simulated driving tests for the evaluation of drivers' reactions and responses.

PubMed

Bartolozzi, Riccardo; Frendo, Francesco

2014-01-01

This article aims at identifying the most significant measures in 2 perception-response (PR) tests performed at a driving simulator: a braking test and a lateral skid test, which were developed in this work. Forty-eight subjects (26 females and 22 males) with a mean age of 24.9 ± 3.0 years were enrolled for this study. They were asked to perform a drive on the driving simulator at the University of Pisa (Italy) following a specific test protocol, including 8-10 braking tests and 8-10 lateral skid tests. Driver input signals and vehicle model signals were recorded during the drives and analyzed to extract measures such as the reaction time, first response time, etc. Following a statistical procedure (based on analysis of variance [ANOVA] and post hoc tests), all test measures (3 for the braking test and 8 for the lateral skid test) were analyzed in terms of statistically significant differences among different drivers. The presented procedure allows evaluation of the capability of a given test to distinguish among different drivers. In the braking test, the reaction time showed a high dispersion among single drivers, leading to just 4.8 percent of statistically significant driver pairs (using the Games-Howell post hoc test), whereas the pedal transition time scored 31.9 percent. In the lateral skid test, 28.5 percent of the 2 × 2 comparisons showed significantly different reaction times, 19.5 percent had different response times, 35.2 percent had a different second peak of the steering wheel signal, and 33 percent showed different values of the integral of the steering wheel signal. For the braking test, which has been widely employed in similar forms in the literature, it was shown how the reaction time, with respect to the pedal transition time, can have a higher dispersion due to the influence of external factors. For the lateral skid test, the following measures were identified as the most significant for application studies: the reaction time for the reaction phase, the second peak of the steering wheel angle for the first instinctive response, and the integral of the steering wheel angle for the complete response. The methodology used to analyze the test measures was founded on statistically based and objective evaluation criteria and could be applied to other tests. Even if obtained with a fixed-base simulator, the obtained results represent useful information for applications of the presented PR tests in experimental campaigns with driving simulators.

On the evolution of high-B radio pulsars with measured braking indices

NASA Astrophysics Data System (ADS)

Benli, O.; Ertan, Ü.

2017-11-01

We have investigated the long-term evolutions of the high-magnetic field radio pulsars (HBRPs) with measured braking indices in the same model that was applied earlier to individual anomalous X-ray pulsars (AXPs), soft gamma repeaters (SGRs) and dim isolated neutron stars (XDINs). We have shown that the rotational properties (period, period derivative and braking index) and the X-ray luminosity of individual HBRPs can be acquired simultaneously by the neutron stars evolving with fallback discs. The model sources reach the observed properties of HBRPs in the propeller phases, when pulsed radio emission is allowed, at ages consistent with the estimated ages of the supernova remnants of the sources. Our results indicate that the strength of magnetic dipole fields of HBRPs are comparable to and even greater than those of AXP/SGRs and XDINs, but still one or two orders of magnitude smaller than the values inferred from the magnetic dipole torque formula. The possible evolutionary paths of the sources imply that they will lose their seemingly HBRP property after about a few 104 yr, because either their rapidly decreasing period derivatives will lead them into the normal radio pulsar population or they will evolve into the accretion phase switching off the radio pulses.

40 CFR 86.007-11 - Emission standards and supplemental requirements for 2007 and later model year diesel heavy-duty...

Code of Federal Regulations, 2011 CFR

2011-07-01

... family are derived from averaging, banking, or trading programs. (ii)(A) Non-Methane Hydrocarbons (NMHC... brake horsepower-hour (0.052 grams per megajoule). (B) Non-Methane Hydrocarbon Equivalent (NMHCE) for... of the given hardware and lead time and production cycles including phase-in or phase-out of engines...

40 CFR 86.007-11 - Emission standards and supplemental requirements for 2007 and later model year diesel heavy-duty...

Code of Federal Regulations, 2013 CFR

2013-07-01

... family are derived from averaging, banking, or trading programs. (ii)(A) Non-Methane Hydrocarbons (NMHC... brake horsepower-hour (0.052 grams per megajoule). (B) Non-Methane Hydrocarbon Equivalent (NMHCE) for... of the given hardware and lead time and production cycles including phase-in or phase-out of engines...

40 CFR 86.007-11 - Emission standards and supplemental requirements for 2007 and later model year diesel heavy-duty...

Code of Federal Regulations, 2010 CFR

2010-07-01

... family are derived from averaging, banking, or trading programs. (ii)(A) Non-Methane Hydrocarbons (NMHC... brake horsepower-hour (0.052 grams per megajoule). (B) Non-Methane Hydrocarbon Equivalent (NMHCE) for... of the given hardware and lead time and production cycles including phase-in or phase-out of engines...

40 CFR 86.007-11 - Emission standards and supplemental requirements for 2007 and later model year diesel heavy-duty...

Code of Federal Regulations, 2014 CFR

2014-07-01

... family are derived from averaging, banking, or trading programs. (ii)(A) Non-Methane Hydrocarbons (NMHC... brake horsepower-hour (0.052 grams per megajoule). (B) Non-Methane Hydrocarbon Equivalent (NMHCE) for... of the given hardware and lead time and production cycles including phase-in or phase-out of engines...

40 CFR 86.007-11 - Emission standards and supplemental requirements for 2007 and later model year diesel heavy-duty...

Code of Federal Regulations, 2012 CFR

2012-07-01

... family are derived from averaging, banking, or trading programs. (ii)(A) Non-Methane Hydrocarbons (NMHC... brake horsepower-hour (0.052 grams per megajoule). (B) Non-Methane Hydrocarbon Equivalent (NMHCE) for... of the given hardware and lead time and production cycles including phase-in or phase-out of engines...

Effect of intake swirl on the performance of single cylinder direct injection diesel engine

NASA Astrophysics Data System (ADS)

Sharma, Vinod Kumar; Mohan, Man; Mouli, Chandra

2017-11-01

In the present work, the effect of inlet manifold geometry and swirl intensity on the direct injection (DI) diesel engine performance was investigated experimentally. Modifications in inlet manifold geometry have been suggested to achieve optimized swirl for the better mixing of fuel with air. The intake swirl intensities of modified cylinder head were measured in swirl test rig at different valve lifts. Later, the overall performance of 435 CC DI diesel engine was measured using modified cylinder head. In addition, the performance of engine was compared for both modified and old cylinder head. For same operating conditions, the brake power and brake specific fuel consumption was improved by 6% and 7% respectively with modified cylinder head compared to old cylinder head. The maximum brake power of 9 HP was achieved for modified cylinder head. The results revealed that the intake swirl has great influence on engine performance.

Establishing pan-European clinical trials: regulatory compliance and other practical considerations.

PubMed

Grienenberger, Aurelie

2004-01-01

There are currently many concerns in the pharmaceutical and scientific community working in or around clinical research on the EU Directive 2001/20/EC or Clinical Trials Directive. The Directive introduces regulatory requirements for all phases of study in human subjects, drawing no distinction between commercially funded drug trials and non-commercial/academic research. The Directive makes Good Clinical Practice (GCP) a legal requirement in Europe and all clinical research will be subjected to the same rigorous standards including GCP and Good Manufacturing Practice (GMP) application even at the early clinical phases as well as exhaustive pharmacovigilance and protection of trial subjects. Some of these requirements may be seen as additional burden and a brake to clinical research in Europe. However, the application of the directive should provide a single and highly regulated market of 25 European countries for investigational medicinal products. This article reviews the main aspects and areas of concern of the Directive and provide US sponsor with useful references.

49 CFR 571.135 - Standard No. 135; Light vehicle brake systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... portable sources of electrical current, and which may include a non-electrical source of power designed to... or more subsystems actuated by a single control, designed so that a single failure in any subsystem....2.1. Pavement friction. Unless otherwise specified, the road test surface produces a peak friction...

49 CFR 571.135 - Standard No. 135; Light vehicle brake systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... portable sources of electrical current, and which may include a non-electrical source of power designed to... or more subsystems actuated by a single control, designed so that a single failure in any subsystem....2.1. Pavement friction. Unless otherwise specified, the road test surface produces a peak friction...

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... current, and which may include a non-electrical source of power designed to charge batteries and... dissipating electrical energy. Skid number means the frictional resistance of a pavement measured in... subsystems actuated by a single control, designed so that a single failure in any subsystem (such as a...

49 CFR 571.135 - Standard No. 135; Light vehicle brake systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... portable sources of electrical current, and which may include a non-electrical source of power designed to... or more subsystems actuated by a single control, designed so that a single failure in any subsystem....2.1. Pavement friction. Unless otherwise specified, the road test surface produces a peak friction...

49 CFR 571.135 - Standard No. 135; Light vehicle brake systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... portable sources of electrical current, and which may include a non-electrical source of power designed to... or more subsystems actuated by a single control, designed so that a single failure in any subsystem....2.1. Pavement friction. Unless otherwise specified, the road test surface produces a peak friction...

49 CFR 571.135 - Standard No. 135; Light vehicle brake systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... portable sources of electrical current, and which may include a non-electrical source of power designed to... or more subsystems actuated by a single control, designed so that a single failure in any subsystem....2.1. Pavement friction. Unless otherwise specified, the road test surface produces a peak friction...

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... current, and which may include a non-electrical source of power designed to charge batteries and... dissipating electrical energy. Skid number means the frictional resistance of a pavement measured in... subsystems actuated by a single control, designed so that a single failure in any subsystem (such as a...

Effect of air-entry angle on performance of a 2-stroke-cycle compression-ignition engine

NASA Technical Reports Server (NTRS)

Earle, Sherod L; Dutee, Francis J

1937-01-01

An investigation was made to determine the effect of variations in the horizontal and vertical air-entry angles on the performance characteristics of a single-cylinder 2-stroke-cycle compression-ignition test engine. Performance data were obtained over a wide range of engine speed, scavenging pressure, fuel quantity, and injection advance angle with the optimum guide vanes. Friction and blower-power curves are included for calculating the indicated and net performances. The optimum horizontal air-entry angle was found to be 60 degrees from the radial and the optimum vertical angle to be zero, under which conditions a maximum power output of 77 gross brake horsepower for a specific fuel consumption of 0.52 pound per brake horsepower-hour was obtained at 1,800 r.p.m. and 16-1/2 inches of Hg scavenging pressure. The corresponding specific output was 0.65 gross brake horsepower per cubic inch of piston displacement. Tests revealed that the optimum scavenging pressure increased linearly with engine speed. The brake mean effective pressure increased uniformly with air quantity per cycle for any given vane angle and was independent of engine speed and scavenging pressure.

Lower extremity sagittal joint moment production during split-belt treadmill walking

PubMed Central

Roemmich, Ryan T.; Stegemöller, Elizabeth L.; Hass, Chris J.

2012-01-01

The split-belt treadmill (SBT) has recently been used to rehabilitate locomotor asymmetries in clinical populations. However, the joint mechanics produced while walking on a SBT are not well-understood. The purpose of this study was to investigate the lower extremity sagittal joint moments produced by each limb during SBT walking and provide insight as to how these joint moment patterns may be useful in rehabilitating unilateral gait deficits. Thirteen healthy young volunteers walked on the SBT with the belts tied and in a “SPLIT” session in which one belt moved twice as fast as the other. Sagittal lower extremity joint moment and ground reaction force impulses were then calculated over the braking and propulsive phases of the gait cycle. Paired t-tests were performed to analyze magnitude differences between conditions (i.e. the fast and slow limbs during SPLIT vs. the same limb during tied-belt walking) and between the fast and slow limbs during SPLIT. During the SPLIT session, the fast limb produced higher ground reaction force and ankle moment impulses during the propulsive and braking phases, and lower knee moment impulses during the propulsive phase when compared to the slow limb. The knee moment impulse was also significantly higher during braking in the slow limb than in the fast limb. The mechanics of each limb during the SPLIT session also differed from the mechanics observed when the belt speeds were tied. Based on these findings, we suggest that each belt may have intrinsic value in rehabilitating specific unilateral locomotor deficits. PMID:22985473

An Adaptive Rear-End Collision Warning System for Drivers That Estimates Driving Phase and Selects Training Data

NASA Astrophysics Data System (ADS)

Ikeda, Kazushi; Mima, Hiroki; Inoue, Yuta; Shibata, Tomohiro; Fukaya, Naoki; Hitomi, Kentaro; Bando, Takashi

The paper proposes a rear-end collision warning system for drivers, where the collision risk is adaptively set from driving signals. The system employs the inverse of the time-to-collision with a constant relative acceleration as the risk and the one-class support vector machine as the anomaly detector. The system also utilizes brake sequences for outliers detection. When a brake sequence has a low likelihood with respect to trained hidden Markov models, the driving data during the sequence are removed from the training dataset. This data selection is confirmed to increase the robustness of the system by computer simulations.

Operator interface for vehicles

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

Bissontz, Jay E

2015-03-10

A control interface for drivetrain braking provided by a regenerative brake and a non-regenerative brake is implemented using a combination of switches and graphic interface elements. The control interface comprises a control system for allocating drivetrain braking effort between the regenerative brake and the non-regenerative brake, a first operator actuated control for enabling operation of the drivetrain braking, and a second operator actuated control for selecting a target braking effort for drivetrain braking. A graphic display displays to an operator the selected target braking effort and can be used to further display actual braking effort achieved by drivetrain braking.

Isolation, biomass estimation and characterization of the biofuel potential of diatom Navicula Sphaerophora

NASA Astrophysics Data System (ADS)

Papu, Nabam Hina; Lingfa, Pradip

2018-04-01

Navicula Sphaerophora was isolated from a fresh water reservoir in Arunachal Pradesh, India. N. Sphaerophora was grown on two different culture media, chu13 medium and Miracle Gro-medium. The maximum yield was obtained by using culture medium chu13(5.08 g/100ml of culture media). Microalgae crude oil was extracted using soxhlation method with three different solvents n-hexane, iso-propanol and hexane/ iso-propanol mixture. The maximum crude oil was obtained using n-hexane as a solvent (13.8% of dry weight biomass). The crude oil was converted into biodiesel using single stage transesterification process with sodium hydroxide (NaOH) as a base catalyst. Fuel properties of algae biodiesel satisfied biodiesel standard ASTM D6751 and use of this fuel should be comparable with petroleum diesel. Further short term engine test was conducted on single cylinder direct injection diesel engine at four different load (25%,50%,75% and 100%). Three different petroleum diesel and Microalgae Biodiesel blends (10%, 20% and 30%) were prepared. The influence of biodiesel blends on BSFC (brake specific fuel consumption), BTE (brake thermal efficiency), oxides of nitrogen (NOx), UBHC (unburnt hydrocarbons), carbonmonoxide (CO) and smoke opacity was studied and compared with petroleum diesel. Microalgae methyl ester 50% blend (B50) had lowest brake thermal efficiency (BTE) and highest Brake specific fuel consumption (BSFC) as compared to diesel; this may be due to Lower calorific value. HC, CO emission and smoke opacity reduces significantly with microalgae methyl ester. However, the NOx emission increases with all blends when compared to petroleum diesel. 10% microalgae blend with petroleum diesel showed the closet performance to petroleum diesel. Results obtained from present investigation confirmed the biofuel potentiality of Navicula Sphaerophora.

Design and performance tests of a distributed power-driven wheel loader

NASA Astrophysics Data System (ADS)

Jin, Xiaolin; Shi, Laide; Bian, Yongming

2010-03-01

An improved ZLM15B distributed power-driven wheel loader was designed, whose travel and brake system was accomplished by two permanent magnet synchronous motorized-wheels instead of traditional mechanical components, and whose hydraulic systems such as the working device system and steering system were both actuated by an induction motor. All above systems were flexibly coupled with 3-phase 380VAC electric power with which the diesel engine power is replaced. On the level cement road, traveling, braking, traction and steering tests were carried out separately under non-load and heavy-load conditions. Data show that machine speed is 5 km/h around and travel efficiency of motorized-wheels is above 95%; that machine braking deceleration is between 0.5 and 0.64 m/s2 but efficiency of motorized-wheels is less than 10%; that maximum machine traction is above 2t while efficiency of motorized-wheels is more than 90% and that adaptive differential steering can be smoothly achieved by motorized-wheels.

Design and performance tests of a distributed power-driven wheel loader

NASA Astrophysics Data System (ADS)

Jin, Xiaolin; Shi, Laide; Bian, Yongming

2009-12-01

An improved ZLM15B distributed power-driven wheel loader was designed, whose travel and brake system was accomplished by two permanent magnet synchronous motorized-wheels instead of traditional mechanical components, and whose hydraulic systems such as the working device system and steering system were both actuated by an induction motor. All above systems were flexibly coupled with 3-phase 380VAC electric power with which the diesel engine power is replaced. On the level cement road, traveling, braking, traction and steering tests were carried out separately under non-load and heavy-load conditions. Data show that machine speed is 5 km/h around and travel efficiency of motorized-wheels is above 95%; that machine braking deceleration is between 0.5 and 0.64 m/s2 but efficiency of motorized-wheels is less than 10%; that maximum machine traction is above 2t while efficiency of motorized-wheels is more than 90% and that adaptive differential steering can be smoothly achieved by motorized-wheels.

Relationship between linear velocity and tangential push force while turning to change the direction of the manual wheelchair.

PubMed

Hwang, Seonhong; Lin, Yen-Sheng; Hogaboom, Nathan S; Wang, Lin-Hwa; Koontz, Alicia M

2017-08-28

Wheelchair propulsion is a major cause of upper limb pain and injuries for manual wheelchair users with spinal cord injuries (SCIs). Few studies have investigated wheelchair turning biomechanics on natural ground surfaces. The purpose of this study was to investigate the relationship between tangential push force and linear velocity of the wheelchair during the turning portions of propulsion. Using an instrumented handrim, velocity and push force data were recorded for 25 subjects while they propel their own wheelchairs on a concrete floor along a figure-eight-shaped course at a maximum velocity. The braking force (1.03 N) of the inside wheel while turning was the largest of all other push forces (p<0.05). Larger changes in squared velocity while turning were significantly correlated with higher propulsive and braking forces used at the pre-turning, turning, and post-turning phases (p<0.05). Subjects with less change of velocity while turning needed less braking force to maneuver themselves successfully and safely around the turns. Considering the magnitude and direction of tangential force applied to the wheel, it seems that there are higher risks of injury and instability for upper limb joints when braking the inside wheel to turn. The results provide insight into wheelchair setup and mobility skills training for wheelchair users.

Transient switching control strategy from regenerative braking to anti-lock braking with a semi-brake-by-wire system

NASA Astrophysics Data System (ADS)

Li, Liang; Li, Xujian; Wang, Xiangyu; Liu, Yahui; Song, Jian; Ran, Xu

2016-02-01

Regenerative braking is an important technology in improving fuel economy of an electric vehicle (EV). However, additional motor braking will change the dynamic characteristics of the vehicle, leading to braking instability, especially when the anti-lock braking system (ABS) is triggered. In this paper, a novel semi-brake-by-wire system, without the use of a pedal simulator and fail-safe device, is proposed. In order to compensate for the hysteretic characteristics of the designed brake system while ensure braking reliability and fuel economy when the ABS is triggered, a novel switching compensation control strategy using sliding mode control is brought forward. The proposed strategy converts the complex coupling braking process into independent control of hydraulic braking and regenerative braking, through which a balance between braking performance, braking reliability, braking safety and fuel economy is achieved. Simulation results show that the proposed strategy is effective and adaptable in different road conditions while the large wheel slip rate is triggered during a regenerative braking course. The research provides a new possibility of low-cost equipment and better control performance for the regenerative braking in the EV and the hybrid EV.

49 CFR 570.58 - Electric brake system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 6 2010-10-01 2010-10-01 false Electric brake system. 570.58 Section 570.58... 10,000 Pounds § 570.58 Electric brake system. (a) Electric brake system integrity. The average brake... reading by the number of brakes and determine the brake amperage value. (b) Electric brake wiring...

49 CFR 570.58 - Electric brake system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 6 2014-10-01 2014-10-01 false Electric brake system. 570.58 Section 570.58... 10,000 Pounds § 570.58 Electric brake system. (a) Electric brake system integrity. The average brake... reading by the number of brakes and determine the brake amperage value. (b) Electric brake wiring...

49 CFR 570.58 - Electric brake system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 6 2012-10-01 2012-10-01 false Electric brake system. 570.58 Section 570.58... 10,000 Pounds § 570.58 Electric brake system. (a) Electric brake system integrity. The average brake... reading by the number of brakes and determine the brake amperage value. (b) Electric brake wiring...

Distinguishing spinocerebellar ataxia with pure cerebellar manifestation from multiple system atrophy (MSA-C) through saccade profiles.

PubMed

Terao, Yasuo; Fukuda, Hideki; Tokushige, Shin-Ichi; Inomata-Terada, Satomi; Yugeta, Akihiro; Hamada, Masashi; Ugawa, Yoshikazu

2017-01-01

Patients with spinocerebellar ataxia with pure cerebellar presentation (SCD) and multiple system atrophy (MSA-C) show similar symptoms at early stages, although cerebellofugal pathology predominates in SCD, and cerebellopetal pathology in MSA-C. We studied whether saccade velocity profiles, which reflect the accelerating and braking functions of the cerebellum, can differentiate these two disorders. We recorded visually guided (VGS) and memory guided saccades (MGS) in 29 MSA-C patients, 12 SCD patients, and 92 age-matched normal subjects, and compared their amplitude, peak velocity and duration (accelerating and decelerating phases). Hypometria predominated in VGS and MGS of MSA-C, whereas hypometria was less marked in SCD, with hypermetria frequently noted in MGS. Peak velocity was reduced, and deteriorated with advancing disease both in SCD and MSA-C groups at smaller target eccentricities. The deceleration phase was prolonged in SCD compared to MSA-C and normal groups at larger target eccentricities, which deteriorated with advancing disease. Saccades in MSA-C were characterized by a more prominent acceleration deficit and those in SCD by a more prominent braking defect, possibly caused by the cerebellopetal and cerebellofugal pathologies, respectively. Saccade profiles provide important information regarding the accelerating and braking signals of the cerebellum in spinocerebellar ataxia. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Optimal design of a hybrid MR brake for haptic wrist application

NASA Astrophysics Data System (ADS)

Nguyen, Quoc Hung; Nguyen, Phuong Bac; Choi, Seung-Bok

2011-03-01

In this work, a new configuration of a magnetorheological (MR) brake is proposed and an optimal design of the proposed MR brake for haptic wrist application is performed considering the required braking torque, the zero-field friction torque, the size and mass of the brake. The proposed MR brake configuration is a combination of disc-type and drum-type which is referred as a hybrid configuration in this study. After the MR brake with the hybrid configuration is proposed, braking torque of the brake is analyzed based on Bingham rheological model of the MR fluid. The zero-field friction torque of the MR brake is also obtained. An optimization procedure based on finite element analysis integrated with an optimization tool is developed for the MR brake. The purpose of the optimal design is to find the optimal geometric dimensions of the MR brake structure that can produce the required braking torque and minimize the uncontrollable torque (passive torque) of the haptic wrist. Based on developed optimization procedure, optimal solution of the proposed MR brake is achieved. The proposed optimized hybrid brake is then compared with conventional types of MR brake and discussions on working performance of the proposed MR brake are described.

Driver kinematic and muscle responses in braking events with standard and reversible pre-tensioned restraints: validation data for human models.

PubMed

Osth, Jonas; Olafsdóttir, Jóna Marín; Davidsson, Johan; Brolin, Karin

2013-11-01

The objectives of this study are to generate validation data for human models intended for simulation of occupant kinematics in a pre-crash phase, and to evaluate the effect of an integrated safety system on driver kinematics and muscle responses. Eleven male and nine female volunteers, driving a passenger car on ordinary roads, performed maximum voluntary braking; they were also subjected to autonomous braking events with both standard and reversible pre-tensioned restraints. Kinematic data was acquired through film analysis, and surface electromyography (EMG) was recorded bilaterally for muscles in the neck, the upper extremities, and lumbar region. Maximum voluntary contractions (MVCs) were carried out in a driving posture for normalization of the EMG. Seat belt positions, interaction forces, and seat indentions were measured. During normal driving, all muscle activity was below 5% of MVC for females and 9% for males. The range of activity during steady state braking for males and females was 13-44% in the cervical and lumbar extensors, while antagonistic muscles showed a co-contraction of 2.3-19%. Seat belt pre-tension affects both the kinematic and muscle responses of drivers. In autonomous braking with standard restraints, muscle activation occurred in response to the inertial load. With pre-tensioned seat belts, EMG onset occurred earlier; between 71 ms and 176 ms after belt pre-tension. The EMG onset times decreased with repeated trials and were shorter for females than for males. With the results from this study, further improvement and validation of human models that incorporate active musculature will be made possible.

Mind the Gap when Data Mining the Ritter-Kolb Cataclysmic Variable Catalogue

NASA Astrophysics Data System (ADS)

Sparks, Warren M.; Sion, Edward M.

2017-01-01

The cataclysmic variable (CV) binary consists of a white dwarf primary and a low-mass secondary which overflows its Roche lobe. The Ritter-Kolb catalogue (2003, A&A, 404, 301) is a collection (~1000) of CV binaries and related objects. We have mined this catalogue for CVs with unevolved secondaries whose mass ratio (secondary/primary) is known (~130). A plot of the secondary mass verses the log of the orbital period exhibits the well-known period gap at 2-3 hrs. In addition, this plot shows that the secondary masses just above the period gap are collectively much larger than those just below. The average of the first ten secondary masses above the period is 180% larger than the average below the gap.The disrupted magnetic braking hypothesis (Howell, Nelson, and Rappaport 2001, ApJ, 550, 897 [HNR]) predicts that when the secondary becomes fully convective, the magnetic braking, which has driven the secondary out of thermal equilibrium, stops. In adjusting to thermal equilibrium the secondary shrinks below its Roche lobe and no longer loses mass. The binary system ceases to appear as a CV until gravitational radiation loss brings the secondary back in contact with its Roche lobe. This scenario is at odds with the apparent secondary mass loss across the period gap. Either the secondary continues to lose mass while crossing the period gap or the secondary masses are miscalculated!Magnetic braking causes the secondary to expand or inflate larger than its single star counterpart. Any orbital parameter calculation which assumes a radius-mass relationship based on single main-sequence stars will overestimate the mass of the secondary. We can approximate this mass overestimation from calculations by HNR which take into account the thermal heating from magnetic braking. Using this approximation as a first-order correction to the secondary mass, we replot the deflated secondary mass versus the binary period. The deflated masses immediately above and below the period gap are similar and do not indicate secondary mass loss across the gap. Thus, magnetic braking not only explains the period gap but the apparent secondary mass shift across it. Orbital parameters must be based upon actual secondary mass-radius observations.

Characterization of Fine Airborne Particulate Collected in Tokyo and Major Atmospheric Emission Sources by Using Single Particle Measurement of SEM-EDX

NASA Astrophysics Data System (ADS)

Sato, K.; Iijima, A.; Furuta, N.

2008-12-01

In our long-term monitoring of size-classified Airborne Particulate Matter (APM) in Tokyo since 1995, it had been demonstrated that toxic elements such as As, Se, Cd, Sb and Pb were extremely enriched in fine APM (PM2.5). However, in that study, total sampled APM on a filter was digested with acids, and thus only averaged elemental composition in fine APM could be obtained. One of the effective methods to determine the origin of APM is single particle measurement by using SEM-EDX. By using characteristic shapes observed by SEM and marker elements contained in APM measured by EDX, detailed information for source identification can be obtained. In this study, fine APM (PM2.5) was collected at various locations such as roadside, diesel vehicle exhaust, a heavy oil combustion plant and a waste incineration plant as well as ambient atmosphere in Tokyo, and characteristics of fine particles that will be utilized for identification of emission sources are elucidated. Fine particles can be classified into 3 main characteristic shape groups; edge-shaped, cotton-like and spherical. Shape of particles collected in a heavy oil combustion plant and a waste incineration plant was mostly spherical, and these particles may be associated with thermal process. Diesel exhaust particles were predominantly cotton-like which may consist of coagulated nano-sized particles. Most of brake abrasion dusts were edge-shaped, which may be associated with mechanical abrasion of brake pads. In the elemental analysis of fine particles, high concentrations of Sb, Cu, Ti and Ba were detected in brake abrasion dusts. Since these elements are major constituents of brake pads, these can be used for marker elements of brake abrasion dusts. High concentration of C was detected in diesel exhaust particles and oil combustion particles, and thus C can be used for marker elements of their origin. Furthermore, high concentrations of C, Ca and K were detected in fly ash from a waste incineration plant, which may be associated with emission from biomass combustion.

Mountain Plains Learning Experience Guide: Automotive Repair. Course: Brake Systems.

ERIC Educational Resources Information Center

Schramm, C.; Osland, Walt

One of twelve individualized courses included in an automotive repair curriculum, this course covers theory, operation, and repair of drum brakes, disc brakes, and brake system components. The course is comprised of six units: (1) Fundamentals of Brake Systems, (2) Master Cylinder, (3) Drum Brakes, (4) Disc Brakes, (5) Power Brakes, and (6)…

Combined hydraulic and regenerative braking system

DOEpatents

Venkataperumal, R.R.; Mericle, G.E.

1979-08-09

A combined hydraulic and regenerative braking system and method for an electric vehicle is disclosed. The braking system is responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially regenerative at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.

Combined hydraulic and regenerative braking system

DOEpatents

Venkataperumal, Rama R.; Mericle, Gerald E.

1981-06-02

A combined hydraulic and regenerative braking system and method for an electric vehicle, with the braking system being responsive to the applied hydraulic pressure in a brake line to control the braking of the vehicle to be completely hydraulic up to a first level of brake line pressure, to be partially hydraulic at a constant braking force and partially regenerative at a linearly increasing braking force from the first level of applied brake line pressure to a higher second level of brake line pressure, to be partially hydraulic at a linearly increasing braking force and partially regenerative at a linearly decreasing braking force from the second level of applied line pressure to a third and higher level of applied line pressure, and to be completely hydraulic at a linearly increasing braking force from the third level to all higher applied levels of line pressure.

Constrained Source Apportionment of Coarse Particulate Matter and Selected Trace Elements in Three Cities from the Multi-Ethnic Study of Atherosclerosis

PubMed Central

Sturtz, Timothy M.; Adar, Sara D.; Gould, Timothy; Larson, Timothy V.

2016-01-01

PM10-2.5 mass and trace element concentrations were measured in Winston-Salem, Chicago, and St. Paul at up to 60 sites per city during two different seasons in 2010. Positive Matrix Factorization (PMF) was used to explore the underlying sources of variability. Information on previously reported PM10-2.5 tire and brake wear profiles was used to constrain these features in PMF by prior specification of selected species ratios. We also modified PMF to allow for combining the measurements from all three cities into a single model while preserving city-specific soil features. Relatively minor differences were observed between model predictions with and without the prior ratio constraints, increasing confidence in our ability to identify separate brake wear and tire wear features. Brake wear, tire wear, fertilized soil, and re-suspended soil were found to be important sources of copper, zinc, phosphorus, and silicon respectively across all three urban areas. PMID:27468256

Constrained source apportionment of coarse particulate matter and selected trace elements in three cities from the multi-ethnic study of atherosclerosis

NASA Astrophysics Data System (ADS)

Sturtz, Timothy M.; Adar, Sara D.; Gould, Timothy; Larson, Timothy V.

2014-02-01

PM10-2.5 mass and trace element concentrations were measured in Winston-Salem, Chicago, and St. Paul at up to 60 sites per city during two different seasons in 2010. Positive Matrix Factorization (PMF) was used to explore the underlying sources of variability. Information on previously reported PM10-2.5 tire and brake wear profiles was used to constrain these features in PMF by prior specification of selected species ratios. We also modified PMF to allow for combining the measurements from all three cities into a single model while preserving city-specific soil features. Relatively minor differences were observed between model predictions with and without the prior ratio constraints, increasing confidence in our ability to identify separate brake wear and tire wear features. Brake wear, tire wear, fertilized soil, and resuspended soil were found to be important sources of copper, zinc, phosphorus, and silicon, respectively, across all three urban areas.

78 FR 25347 - Petition for Waiver of Compliance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-30

.... Specifically, BNSF and UP seek a waiver of compliance from 49 CFR 232.305(b)(2) for railroad cars tested with automatic single car test devices (ASCTD). The current rule stipulates that if a car is on a shop or repair track for any reason and has not had a single car air brake test within the previous 12-month period, a...

49 CFR 393.53 - Automatic brake adjusters and brake adjustment indicators.

Code of Federal Regulations, 2010 CFR

2010-10-01

... indicators. 393.53 Section 393.53 Transportation Other Regulations Relating to Transportation (Continued... brake adjustment indicators. (a) Automatic brake adjusters (hydraulic brake systems). Each commercial... vehicle at the time it was manufactured. (c) Brake adjustment indicator (air brake systems). On each...

49 CFR 393.53 - Automatic brake adjusters and brake adjustment indicators.

Code of Federal Regulations, 2011 CFR

2011-10-01

... indicators. 393.53 Section 393.53 Transportation Other Regulations Relating to Transportation (Continued... brake adjustment indicators. (a) Automatic brake adjusters (hydraulic brake systems). Each commercial... vehicle at the time it was manufactured. (c) Brake adjustment indicator (air brake systems). On each...

Effect of an Arm Swing on Countermovement Vertical Jump Performance in Elite Volleyball Players: FINAL.

PubMed

Vaverka, Frantisek; Jandačka, Daniel; Zahradník, David; Uchytil, Jaroslav; Farana, Roman; Supej, Matej; Vodičar, Janez

2016-12-01

The aim of this study was to determine how elite volleyball players employed the arm swing (AS) to enhance their jump performance. The study assessed how the AS influenced the duration and magnitude of the vertical ground reaction force (VGRF) during the main phases (preparatory, braking and accelerating) of the countermovement vertical jump (CMVJ), the starting position of the body at the beginning of the accelerating phase and the moment when the AS began contributing to increasing the jump height. Eighteen elite volleyball players performed three CMVJs with and without an AS. Kinetics and kinematics data were collected using two Kistler force plates and the C-motion system. The time and force variables were evaluated based on the VGRF, and the position of the body and the trajectory of the arm movement were determined using kinematic analysis. The AS improved the CMVJ by increasing the jump height by 38% relative to jumping without an AS. The AS significantly shortened the braking phase and prolonged the accelerating phase, however, it did not influence the preparatory phase or the overall jump duration. The AS also significantly increased the average force during the accelerating phase as well as the accelerating impulse. The AS upward began at 76% into the overall jump duration. The AS did not influence the body position at the beginning of the accelerating phase. These findings can be used to improve performance of the CMVJ with the AS and in teaching beginning volleyball players proper jumping technique.

Disordered cellular automaton traffic flow model: phase separated state, density waves and self organized criticality

NASA Astrophysics Data System (ADS)

Fourrate, K.; Loulidi, M.

2006-01-01

We suggest a disordered traffic flow model that captures many features of traffic flow. It is an extension of the Nagel-Schreckenberg (NaSch) stochastic cellular automata for single line vehicular traffic model. It incorporates random acceleration and deceleration terms that may be greater than one unit. Our model leads under its intrinsic dynamics, for high values of braking probability pr, to a constant flow at intermediate densities without introducing any spatial inhomogeneities. For a system of fast drivers pr→0, the model exhibits a density wave behavior that was observed in car following models with optimal velocity. The gap of the disordered model we present exhibits, for high values of pr and random deceleration, at a critical density, a power law distribution which is a hall mark of a self organized criticality phenomena.

Microstructural Formations and Phase Transformation Pathways in Hot Isostatically Pressed Tantalum Carbides

DTIC Science & Technology

2012-01-01

and wear-resistant brake liners. The phase diagram for the tantalum–carbon system [5] is shown in Fig. 1a with corresponding crystal structures shown... structure ), with carbon atoms occupying the octahe- dral interstitial sites in a tantalum face-centered cubic (fcc) lattice [2,7]. The carbon-deficient...carbon sublattice. The allotropic phase trans- formation temperature between a-Ta2C (CdI2 antitype structure ) and b (L’3 structure ) is 2300 K [1,7]. In

An Australian study to evaluate worker exposure to chrysotile in the automotive service industry.

PubMed

Yeung, P; Patience, K; Apthorpe, L; Willcocks, D

1999-07-01

A study was conducted in Sydney, Australia, in 1996 to investigate the current exposure levels, control technologies, and work practices in five service garages (four car and one bus), three brake bonding workshops, and one gasket processing workshop. This study formed part of the assessment of chrysotile as a priority existing chemical under the Australian National Industrial Chemicals Notification and Assessment Scheme. A total of 68 (11 personal and 57 area) air samples were collected, in accordance with the Australian standard membrane filter method. Fiber concentrations were determined by the traditional phase contrast microscopy (PCM) method and 16 selected samples were analyzed by the more powerful transmission electron microscopy (TEM). Chrysotile exposure of car mechanics measured by PCM was typically below the reportable detection limit of 0.05 f/mL, irrespective of whether disc brake, drum brake, or clutch was being serviced. These low levels can be attributed to the wet cleaning or aerosol spray methods used in recent years to replace the traditional compressed air jet cleaning. In the three brake shoe relining workshops, task-specific exposure reached up to 0.16 f/mL in the processes of cutting and radius grinding. TEM results were generally higher, due to its higher resolution power. The median diameter on samples taken from the service garages (passenger cars), as determined by TEM, was 0.5-1.0 micron; and was between 0.2-0.5 micron for the brake bonding and gasket processing workshops, while that for the bus service depot was 0.1-0.2 micron. Most of the respirable fibers (84%, mainly forsterite) from the bus service depot were below 0.2 micron in diameter which is the resolution limit of PCM. In the brake bonding and gasket cutting workshops, 34 percent and 44 percent of the chrysotile fibers were below 0.2 micron in diameter.

49 CFR 393.41 - Parking brake system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... NECESSARY FOR SAFE OPERATION Brakes § 393.41 Parking brake system. (a) Hydraulic-braked vehicles... road (free of ice and snow). Hydraulic-braked vehicles which were not subject to the parking brake... spring action. If other energy is used to apply the parking brake, there must be an accumulation of that...

49 CFR 393.41 - Parking brake system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... NECESSARY FOR SAFE OPERATION Brakes § 393.41 Parking brake system. (a) Hydraulic-braked vehicles... road (free of ice and snow). Hydraulic-braked vehicles which were not subject to the parking brake... spring action. If other energy is used to apply the parking brake, there must be an accumulation of that...

49 CFR 393.41 - Parking brake system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... NECESSARY FOR SAFE OPERATION Brakes § 393.41 Parking brake system. (a) Hydraulic-braked vehicles... road (free of ice and snow). Hydraulic-braked vehicles which were not subject to the parking brake... spring action. If other energy is used to apply the parking brake, there must be an accumulation of that...

49 CFR 570.56 - Vacuum brake assist unit and vacuum brake system.

Code of Federal Regulations, 2010 CFR

2010-10-01

.... The following requirements apply to vehicles with vacuum brake assist units and vacuum brake systems. (a) Vacuum brake assist unit integrity. The vacuum brake assist unit shall demonstrate integrity as... maintained on the pedal. (1) Inspection procedure. Stop the engine and apply service brake several times to...

49 CFR 393.52 - Brake performance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Brake performance. 393.52 Section 393.52... NECESSARY FOR SAFE OPERATION Brakes § 393.52 Brake performance. (a) Upon application of its service brakes... braking force is measured by a performance-based brake tester which meets the requirements of functional...

49 CFR 393.52 - Brake performance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 5 2013-10-01 2013-10-01 false Brake performance. 393.52 Section 393.52... NECESSARY FOR SAFE OPERATION Brakes § 393.52 Brake performance. (a) Upon application of its service brakes... braking force is measured by a performance-based brake tester which meets the requirements of functional...

49 CFR 393.52 - Brake performance.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 5 2014-10-01 2014-10-01 false Brake performance. 393.52 Section 393.52... NECESSARY FOR SAFE OPERATION Brakes § 393.52 Brake performance. (a) Upon application of its service brakes... braking force is measured by a performance-based brake tester which meets the requirements of functional...

49 CFR 393.52 - Brake performance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 5 2010-10-01 2010-10-01 false Brake performance. 393.52 Section 393.52... NECESSARY FOR SAFE OPERATION Brakes § 393.52 Brake performance. (a) Upon application of its service brakes... braking force is measured by a performance-based brake tester which meets the requirements of functional...

49 CFR 393.52 - Brake performance.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 5 2012-10-01 2012-10-01 false Brake performance. 393.52 Section 393.52... NECESSARY FOR SAFE OPERATION Brakes § 393.52 Brake performance. (a) Upon application of its service brakes... braking force is measured by a performance-based brake tester which meets the requirements of functional...

Thermal analysis and temperature characteristics of a braking resistor for high-speed trains for changes in the braking current

NASA Astrophysics Data System (ADS)

Lee, Dae-Dong; Kang, Hyun-Il; Shim, Jae-Myung

2015-09-01

Electric brake systems are used in high-speed trains to brake trains by converting the kinetic energy of a railway vehicle to electric energy. The electric brake system consists of a regenerative braking system and a dynamic braking system. When the electric energy generated during the dynamic braking process is changed to heat through the braking resistor, the braking resistor can overheat; thus, failures can occur to the motor block. In this paper, a braking resistor for a high-speed train was used to perform thermal analyses and tests, and the results were analyzed. The analyzed data were used to estimate the dependence of the brake currents and the temperature rises on speed changes up to 300 km/h, at which a test could not be performed.

A successful backward step correlates with hip flexion moment of supporting limb in elderly people.

PubMed

Takeuchi, Yahiko

2018-01-01

The objective of this study was to determine the positional relationship between the center of mass (COM) and the center of pressure (COP) at the time of step landing, and to examine their relationship with the joint moments exerted by the supporting limb, with regard to factors of the successful backward step response. The study population comprised 8 community-dwelling elderly people that were observed to take successive multi steps after the landing of a backward stepping. Using a motion capture system and force plate, we measured the COM, COP and COM-COP deviation distance on landing during backward stepping. In addition, we measured the moment of the supporting limb joint during backward stepping. The multi-step data were compared with data from instances when only one step was taken (single-step). Variables that differed significantly between the single- and multi-step data were used as objective variables and the joint moments of the supporting limb were used as explanatory variables in single regression analyses. The COM-COP deviation in the anteroposterior was significantly larger in the single-step. A regression analysis with COM-COP deviation as the objective variable obtained a significant regression equation in the hip flexion moment (R2 = 0.74). The hip flexion moment of supporting limb was shown to be a significant explanatory variable in both the PS and SS phases for the relationship with COM-COP distance. This study found that to create an appropriate backward step response after an external disturbance (i.e. the ability to stop after 1 step), posterior braking of the COM by a hip flexion moment are important during the single-limbed standing phase.

Adaptive cruise control with stop&go function using the state-dependent nonlinear model predictive control approach.

PubMed

Shakouri, Payman; Ordys, Andrzej; Askari, Mohamad R

2012-09-01

In the design of adaptive cruise control (ACC) system two separate control loops - an outer loop to maintain the safe distance from the vehicle traveling in front and an inner loop to control the brake pedal and throttle opening position - are commonly used. In this paper a different approach is proposed in which a single control loop is utilized. The objective of the distance tracking is incorporated into the single nonlinear model predictive control (NMPC) by extending the original linear time invariant (LTI) models obtained by linearizing the nonlinear dynamic model of the vehicle. This is achieved by introducing the additional states corresponding to the relative distance between leading and following vehicles, and also the velocity of the leading vehicle. Control of the brake and throttle position is implemented by taking the state-dependent approach. The model demonstrates to be more effective in tracking the speed and distance by eliminating the necessity of switching between the two controllers. It also offers smooth variation in brake and throttle controlling signal which subsequently results in a more uniform acceleration of the vehicle. The results of proposed method are compared with other ACC systems using two separate control loops. Furthermore, an ACC simulation results using a stop&go scenario are shown, demonstrating a better fulfillment of the design requirements. Copyright © 2012 ISA. Published by Elsevier Ltd. All rights reserved.

An integrated control strategy for the composite braking system of an electric vehicle with independently driven axles

NASA Astrophysics Data System (ADS)

Sun, Fengchun; Liu, Wei; He, Hongwen; Guo, Hongqiang

2016-08-01

For an electric vehicle with independently driven axles, an integrated braking control strategy was proposed to coordinate the regenerative braking and the hydraulic braking. The integrated strategy includes three modes, namely the hybrid composite mode, the parallel composite mode and the pure hydraulic mode. For the hybrid composite mode and the parallel composite mode, the coefficients of distributing the braking force between the hydraulic braking and the two motors' regenerative braking were optimised offline, and the response surfaces related to the driving state parameters were established. Meanwhile, the six-sigma method was applied to deal with the uncertainty problems for reliability. Additionally, the pure hydraulic mode is activated to ensure the braking safety and stability when the predictive failure of the response surfaces occurs. Experimental results under given braking conditions showed that the braking requirements could be well met with high braking stability and energy regeneration rate, and the reliability of the braking strategy was guaranteed on general braking conditions.

A method to achieve comparable thermal states of car brakes during braking on the road and on a high-speed roll-stand

NASA Astrophysics Data System (ADS)

Wolff, Andrzej

2010-01-01

The temperature of a brake friction surface influences significantly the braking effectiveness. The paper describes a heat transfer process in car brakes. Using a developed program of finite element method, the temperature distributions in brake rotors (disc and drum brake) of a light truck have been calculated. As a preliminary consistency criterion of the brake thermal state in road and roll-stand braking conditions, a balance of the energy cumulated in the brake rotor has been taken into account. As the most reliable consistency criterion an equality of average temperatures of the friction surface has been assumed. The presented method allows to achieve on a roll-stand the analogical thermal states of automotive brakes, which are observed during braking in road conditions. Basing on this method, it is possible to calculate the braking time and force for a high-speed roll-stand. In contrast to the previous papers of the author, new calculation results have been presented.

Brakes: Traffic Safety Tips

DOT National Transportation Integrated Search

1996-01-01

This fact sheet, NHTSA Facts: Summer 1996, describes traffic safety tips about brakes. It discusses drum brakes, disc brakes, and antilock braking systsms. It notes that there are government standards for brakes, and describes how to take care of bra...

Method and apparatus for electromagnetically braking a motor

NASA Technical Reports Server (NTRS)

Davis, Donald R. (Inventor); Radford, Nicolaus A (Inventor); Permenter, Frank Noble (Inventor); Parsons, Adam H (Inventor); Mehling, Joshua S (Inventor)

2011-01-01

An electromagnetic braking system and method is provided for selectively braking a motor using an electromagnetic brake having an electromagnet, a permanent magnet, a rotor assembly, and a brake pad. The brake assembly applies when the electromagnet is de-energized and releases when the electromagnet is energized. When applied the permanent magnet moves the brake pad into frictional engagement with a housing, and when released the electromagnet cancels the flux of the permanent magnet to allow a leaf spring to move the brake pad away from the housing. A controller has a DC/DC converter for converting a main bus voltage to a lower braking voltage based on certain parameters. The converter utilizes pulse-width modulation (PWM) to regulate the braking voltage. A calibrated gap is defined between the brake pad and permanent magnet when the brake assembly is released, and may be dynamically modified via the controller.

Development and Test of an Eddy-Current Clutch-Propulsion System

DOT National Transportation Integrated Search

1973-10-01

This report covers the Phase 1 effort which is to develop and to test an/AC-propulsion system for personal rapid- transit vehicles. This propulsion system incorporates an AC-induction motor in conjunction with an eddy-current clutch and brake. Also i...

The tearing mode locking-unlocking mechanism to an external resonant field in EXTRAP T2R

NASA Astrophysics Data System (ADS)

Frassinetti, L.; Fridström, R.; Menmuir, S.; Brunsell, P. R.

2014-10-01

The tearing mode (TM) locking and unlocking process due to an external resonant magnetic perturbation (RMP) is experimentally studied in EXTRAP T2R. The RMP produces a reduction of the natural TM velocity and ultimately the TM locking if a threshold in the RMP amplitude is exceeded. During the braking process, the TM slows down via a mechanism composed of deceleration and acceleration phases. During the acceleration phases, the TM can reach velocities higher than the natural velocity. Once the TM locking occurs, the RMP must be reduced to a small amplitude to obtain the TM unlocking, showing that the unlocking threshold is significantly smaller than the locking threshold and that the process is characterized by hysteresis. Experimental results are in qualitative agreement with a model that describes the locking-unlocking process via the balance of the electromagnetic torque produced by the RMP that acts to brake the TM and the viscous torque that tends to re-establish the unperturbed velocity.

Cost Analysis of Utilizing Electric Vehicles and Photovoltaic Solar Energy in the United States Marine Corps Commercial Vehicle Fleet

DTIC Science & Technology

2009-12-01

vehicles so do some electric vehicle braking systems (MIT, 2008). e. Brakes Regenerative braking on electric vehicles recoups some of the energy lost...engine is required to replace the energy lost by braking . Regenerative braking takes some of the lost energy during braking and turns it into...Motors and Tesla Motors offer regenerative breaking in their respective electric vehicles. Tesla explains regenerative braking as “engine braking

Visual and cognitive predictors of performance on brake reaction test: Salisbury eye evaluation driving study.

PubMed

Zhang, Lei; Baldwin, Kevin; Munoz, Beatriz; Munro, Cynthia; Turano, Kathleen; Hassan, Shirin; Lyketsos, Constantine; Bandeen-Roche, Karen; West, Sheila K

2007-01-01

Concern for driving safety has prompted research into understanding factors related to performance. Brake reaction speed (BRS), the speed with which persons react to a sudden change in driving conditions, is a measure of performance. Our aim is to determine the visual, cognitive, and physical factors predicting BRS in a population sample of 1425 older drivers. The Maryland Department of Motor Vehicles roster of persons aged 67-87 and residing in Salisbury, MD, was used for recruitment of the study population. Procedures included the following: habitual, binocular visual acuity using ETDRS charts, contrast sensitivity using a Pelli-Robson chart, visual fields assessed with a 81-point screening Humphrey field at a single intensity threshold, and a questionnaire to ascertain medical conditions. Cognitive status was assessed using a standard battery of tests for attention, memory, visuo-spatial, and scanning. BRS was assessed using a computer-driven device that measured separately the initial reaction speed (IRS) (from light change to red until removing foot from accelerator) and physical response speed (PRS) (removing foot from accelerator to full brake depression). Five trial times were averaged, and time was converted to speed. The median brake reaction time varied from 384 to 5688 milliseconds. Age, gender, and cognition predicted total BRS, a non-informative result as there are two distinct parts to the task. Once separated, decrease in IRS was associated with low scores on cognitive factors and missing points on the visual field. A decrease in PRS was associated with having three or more physical complaints related to legs and feet, and poorer vision search. Vision was not related to PRS. We have demonstrated the importance of segregating the speeds for the two tasks involved in brake reaction. Only the IRS depends on vision. Persons in good physical condition may perform poorly on brake reaction tests if their vision or cognition is compromised.

49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

Code of Federal Regulations, 2014 CFR

2014-10-01

... pressure drop in psi per minute with brakes released and with brakes fully applied. (d) Air-over-hydraulic... 49 Transportation 6 2014-10-01 2014-10-01 false Air brake system and air-over-hydraulic brake... STANDARDS Vehicles With GVWR of More Than 10,000 Pounds § 570.57 Air brake system and air-over-hydraulic...

49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

Code of Federal Regulations, 2010 CFR

2010-10-01

... pressure drop in psi per minute with brakes released and with brakes fully applied. (d) Air-over-hydraulic... 49 Transportation 6 2010-10-01 2010-10-01 false Air brake system and air-over-hydraulic brake... STANDARDS Vehicles With GVWR of More Than 10,000 Pounds § 570.57 Air brake system and air-over-hydraulic...

49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

Code of Federal Regulations, 2012 CFR

2012-10-01

... pressure drop in psi per minute with brakes released and with brakes fully applied. (d) Air-over-hydraulic... 49 Transportation 6 2012-10-01 2012-10-01 false Air brake system and air-over-hydraulic brake... STANDARDS Vehicles With GVWR of More Than 10,000 Pounds § 570.57 Air brake system and air-over-hydraulic...

49 CFR 570.57 - Air brake system and air-over-hydraulic brake subsystem.

Code of Federal Regulations, 2013 CFR

2013-10-01

... pressure drop in psi per minute with brakes released and with brakes fully applied. (d) Air-over-hydraulic... 49 Transportation 6 2013-10-01 2013-10-01 false Air brake system and air-over-hydraulic brake... STANDARDS Vehicles With GVWR of More Than 10,000 Pounds § 570.57 Air brake system and air-over-hydraulic...

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

Li Zhiyun; Krasnopolsky, Ruben; Shang Hsien

Dense, star-forming cores of molecular clouds are observed to be significantly magnetized. A realistic magnetic field of moderate strength has been shown to suppress, through catastrophic magnetic braking, the formation of a rotationally supported disk (RSD) during the protostellar accretion phase of low-mass star formation in the ideal MHD limit. We address, through two-dimensional (axisymmetric) simulations, the question of whether realistic levels of non-ideal effects, computed with a simplified chemical network including dust grains, can weaken the magnetic braking enough to enable an RSD to form. We find that ambipolar diffusion (AD), the dominant non-ideal MHD effect over most ofmore » the density range relevant to disk formation, does not enable disk formation, at least in two dimensions. The reason is that AD allows the magnetic flux that would be dragged into the central stellar object in the ideal MHD limit to pile up instead in a small circumstellar region, where the magnetic field strength (and thus the braking efficiency) is greatly enhanced. We also find that, on the scale of tens of AU or more, a realistic level of Ohmic dissipation does not weaken the magnetic braking enough for an RSD to form, either by itself or in combination with AD. The Hall effect, the least explored of these three non-ideal MHD effects, can spin up the material close to the central object to a significant, supersonic rotation speed, even when the core is initially non-rotating, although the spun-up material remains too sub-Keplerian to form an RSD. The problem of catastrophic magnetic braking that prevents disk formation in dense cores magnetized to realistic levels remains unresolved. Possible resolutions of this problem are discussed.« less

Advanced Natural Gas Reciprocating Engines(s)

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

Zurlo, James

The ARES program was initiated in 2001 to improve the overall brake thermal efficiency of stationary, natural gas, reciprocating engines. The ARES program is a joint award that is shared by Dresser, Inc., Caterpillar and Cummins. The ARES program was divided into three phases; ARES I (achieve 44% BTE), ARES II (achieve 47% BTE) and ARES III (achieve 50% BTE). Dresser, Inc. completed ARES I in March 2005 which resulted in the commercialization of the APG1000 product line. ARES II activities were completed in September 2010 and the technology developed is currently being integrated into products. ARES III activities beganmore » in October 2010. The ARES program goal is to improve the efficiency of natural gas reciprocating engines. The ARES project is structured in three phases with higher efficiency goals in each phase. The ARES objectives are as follows: 1. Achieve 44% (ARES I), 47% (ARES II), and 50% brake thermal efficiency (BTE) as a final ARES III objective 2. Achieve 0.1 g/bhp-hr NOx emissions (with after-treatment) 3. Reduce the cost of the produced electricity by 10% 4. Improve or maintain reliability, durability and maintenance costs« less

Automotive Brake Systems.

ERIC Educational Resources Information Center

Marine Corps Inst., Washington, DC.

This correspondence course, orginally developed for the Marine Corps, is designed to provide mechanics with an understanding of the basic operations of automotive brake systems on military vehicles. The course contains four study units covering hydraulic brakes, air brakes, power brakes, and auxiliary brake systems. A troubleshooting guide for…

Rail Brake System Using a Linear Induction Motor for Dynamic Braking

NASA Astrophysics Data System (ADS)

Sakamoto, Yasuaki; Kashiwagi, Takayuki; Tanaka, Minoru; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo

One type of braking system for railway vehicles is the eddy current brake. Because this type of brake has the problem of rail heating, it has not been used for practical applications in Japan. Therefore, we proposed the use of a linear induction motor (LIM) for dynamic braking in eddy current brake systems. The LIM reduces rail heating and uses an inverter for self excitation. In this paper, we estimated the performance of an LIM from experimental results of a fundamental test machine and confirmed that the LIM generates an approximately constant braking force under constant current excitation. At relatively low frequencies, this braking force remains unaffected by frequency changes. The reduction ratio of rail heating is also approximately proportional to the frequency. We also confirmed that dynamic braking resulting in no electrical output can be used for drive control of the LIM. These characteristics are convenient for the realization of the LIM rail brake system.

14 CFR 25.735 - Brakes and braking systems.

Code of Federal Regulations, 2014 CFR

2014-01-01

... speed. The most severe landing stop brake kinetic energy absorption requirement of each wheel, brake... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Brakes and braking systems. 25.735 Section 25.735 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT...

14 CFR 25.735 - Brakes and braking systems.

Code of Federal Regulations, 2012 CFR

2012-01-01

... speed. The most severe landing stop brake kinetic energy absorption requirement of each wheel, brake... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Brakes and braking systems. 25.735 Section 25.735 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT...

14 CFR 25.735 - Brakes and braking systems.

Code of Federal Regulations, 2013 CFR

2013-01-01

... speed. The most severe landing stop brake kinetic energy absorption requirement of each wheel, brake... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Brakes and braking systems. 25.735 Section 25.735 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT...

77 FR 42454 - Airworthiness Directives; Piaggio Aero Industries S.p.A.

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-19

... the brake hydraulic fluid from leaking because of the brake assembly rods contacting the brake valve... session during which conflicting inputs were given to the brake pads between pilot and copilot, a brake... tubings connected to the brake valves, with consequent fluid leakage. Prompted by these findings, PAI...

49 CFR 570.58 - Electric brake system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... missing. Terminal connections shall be clean. Conductor wire gauge shall not be below the brake... 49 Transportation 6 2013-10-01 2013-10-01 false Electric brake system. 570.58 Section 570.58... 10,000 Pounds § 570.58 Electric brake system. (a) Electric brake system integrity. The average brake...

14 CFR 25.735 - Brakes and braking systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... an automatic braking system is installed, means are provided to: (i) Arm and disarm the system, and (ii) Allow the pilot(s) to override the system by use of manual braking. (d) Parking brake. The airplane must have a parking brake control that, when selected on, will, without further attention, prevent...

14 CFR 25.735 - Brakes and braking systems.

Code of Federal Regulations, 2010 CFR

2010-01-01

... an automatic braking system is installed, means are provided to: (i) Arm and disarm the system, and (ii) Allow the pilot(s) to override the system by use of manual braking. (d) Parking brake. The airplane must have a parking brake control that, when selected on, will, without further attention, prevent...

An antilock molecular braking system.

PubMed

Sun, Wei-Ting; Huang, Shou-Ling; Yao, Hsuan-Hsiao; Chen, I-Chia; Lin, Ying-Chih; Yang, Jye-Shane

2012-08-17

A light-driven molecular brake displaying an antilock function is constructed by introducing a nonradiative photoinduced electron transfer (PET) decay channel to compete with the trans (brake-off) → cis (brake-on) photoisomerization. A fast release of the brake can be achieved by deactivating the PET process through addition of protons. The cycle of irradiation-protonation-irradiation-deprotonation conducts the brake function and mimics the antilock braking system (ABS) of vehicles.

Modeling of electromagnetic brakes for enhanced braking capabilities

NASA Astrophysics Data System (ADS)

Kachroo, Pushkin; Ming, Qian

1998-01-01

In automatic highway systems, automatic brake actuation is a very important part of the overall control of the vehicle. Hence, a faster response and a robust braking system are crucial. This paper describes electromagnetic brakes as a supplementary system for regular friction brakes. This system provides better response time for emergency situations, and in general keeps the friction brake working longer and safer. A new mathematical model for electromagnetic brakes is proposed to describe their static characteristics. The performance of the new mathematical model is better than the other three models available in the literature.

Excitation Method of Linear-Motor-Type Rail Brake without Using Power Sources by Dynamic Braking with Zero Electrical Output

NASA Astrophysics Data System (ADS)

Sakamoto, Yasuaki; Kashiwagi, Takayuki; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo

The eddy current rail brake is a type of braking system used in railway vehicles. Because of problems such as rail heating and problems associated with ensuring that power is supplied when the feeder malfunctions, this braking system has not been used for practical applications in Japan. Therefore, we proposed the use of linear induction motor (LIM) technology in eddy current rail brake systems. The LIM rail brake driven by dynamic braking can reduce rail heating and generate the energy required for self-excitation. In this paper, we present an excitation system and control method for the LIM rail brake driven by “dynamic braking with zero electrical output”. The proposed system is based on the concept that the LIM rail brake can be energized without using excitation power sources such as a feeder circuit and that high reliability can be realized by providing an independent excitation system. We have studied this system and conducted verification tests using a prototype LIM rail brake on a roller rig. The results show that the system performance is adequate for commercializing the proposed system, in which the LIM rail brake is driven without using any excitation power source.

Design and multi-physics optimization of rotary MRF brakes

NASA Astrophysics Data System (ADS)

Topcu, Okan; Taşcıoğlu, Yiğit; Konukseven, Erhan İlhan

2018-03-01

Particle swarm optimization (PSO) is a popular method to solve the optimization problems. However, calculations for each particle will be excessive when the number of particles and complexity of the problem increases. As a result, the execution speed will be too slow to achieve the optimized solution. Thus, this paper proposes an automated design and optimization method for rotary MRF brakes and similar multi-physics problems. A modified PSO algorithm is developed for solving multi-physics engineering optimization problems. The difference between the proposed method and the conventional PSO is to split up the original single population into several subpopulations according to the division of labor. The distribution of tasks and the transfer of information to the next party have been inspired by behaviors of a hunting party. Simulation results show that the proposed modified PSO algorithm can overcome the problem of heavy computational burden of multi-physics problems while improving the accuracy. Wire type, MR fluid type, magnetic core material, and ideal current inputs have been determined by the optimization process. To the best of the authors' knowledge, this multi-physics approach is novel for optimizing rotary MRF brakes and the developed PSO algorithm is capable of solving other multi-physics engineering optimization problems. The proposed method has showed both better performance compared to the conventional PSO and also has provided small, lightweight, high impedance rotary MRF brake designs.

Timing Young Pulsars: Challenges to Standard Pulsar Spin-Down Models

NASA Astrophysics Data System (ADS)

Livingstone, Margaret Anne

Pulsars are rapidly rotating neutron stars which are often noted for their very regular rotation rates. Young pulsars, however, frequently exhibit two types of deviations from steady spin down, "glitches" - sudden jumps in spin frequency, which provide insight into pulsar interiors, and "timing noise," a smooth stochastic wander of the pulse phase over long time periods. The youngest pulsars also offer a window into the physics that govern pulsar spin down via the measurement of the "braking index" - a parameter that relates the observable spin frequency of the pulsar with the slowing down torque acting on the neutron star. This thesis discusses long-term timing observations of two young pulsars. First, we present observations of PSR J0205+6449, acquired with the Green Bank Telescope, the Jodrell Bank Observatory and the Rossi X-ray Timing Explorer . We present phase-coherent timing analyses showing timing noise and two spin-up glitches. We also present an X-ray pulse profile analysis showing that the pulsar is detected up to ∼40 keV and does not vary appreciably over four years. We report the phase offset between the radio and X-ray pulse, showing that the radio pulse leads by φ = 0.10 ± 0.01 in phase. We compile measurements of phase offsets for this and other X-ray and γ-ray pulsars and show that there is no relationship between pulse period and phase offset. Next, we present 10 years of monitoring of PSR J1846-0258 with the Rossi X-ray Timing Explorer . We report the first measurement of the braking index for this pulsar, n = 2.65 ± 0.01, only the sixth such measurement ever made, and show that the pulsar experienced a small glitch in 2001. In May 2006, PSR J1846-0258 was briefly transformed: it exhibited a series of X-ray bursts, a dramatic increase in the source flux, and significant softening of its X-ray spectrum - behaviours best explained in the context of the magnetar model. PSR J1846-0258 was thus identified as the first rotation-powered pulsar/magnetar transition object. We quantify the properties of a large glitch that occurred contemporaneously with the outburst, and show that it is unique among pulsar glitches in that it had an over-shoot recovery of 870 ± 250%, resulting in a net decrease of the spin-frequency. We also report torque variations over a period of several hundred days during the period of glitch recovery, that are reminiscent of behaviour seen in some magnetars. Finally, we report that the post-outburst braking index for PSR J1846-0258 is n = 2.16±0.13, corresponding to a decrease of 18±5% relative to its pre-burst value, the first significant change measured in any braking index. We also show that four years after the outburst, the timing noise remains at a higher state than its pre-burst quiescent level.

49 CFR 230.77 - Foundation brake gear.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 230.77 Section 230.77... Tenders Brake and Signal Equipment § 230.77 Foundation brake gear. (a) Maintenance. Foundation brake gear...) Distance above the rails. No part of the foundation brake gear of the steam locomotive or tender shall be...

Optimal design of disc-type magneto-rheological brake for mid-sized motorcycle: experimental evaluation

NASA Astrophysics Data System (ADS)

Sohn, Jung Woo; Jeon, Juncheol; Nguyen, Quoc Hung; Choi, Seung-Bok

2015-08-01

In this paper, a disc-type magneto-rheological (MR) brake is designed for a mid-sized motorcycle and its performance is experimentally evaluated. The proposed MR brake consists of an outer housing, a rotating disc immersed in MR fluid, and a copper wire coiled around a bobbin to generate a magnetic field. The structural configuration of the MR brake is first presented with consideration of the installation space for the conventional hydraulic brake of a mid-sized motorcycle. The design parameters of the proposed MR brake are optimized to satisfy design requirements such as the braking torque, total mass of the MR brake, and cruising temperature caused by the magnetic-field friction of the MR fluid. In the optimization procedure, the braking torque is calculated based on the Herschel-Bulkley rheological model, which predicts MR fluid behavior well at high shear rate. An optimization tool based on finite element analysis is used to obtain the optimized dimensions of the MR brake. After manufacturing the MR brake, mechanical performances regarding the response time, braking torque and cruising temperature are experimentally evaluated.

Dynactin functions as both a dynamic tether and brake during dynein-driven motility

NASA Astrophysics Data System (ADS)

Ayloo, Swathi; Lazarus, Jacob E.; Dodda, Aditya; Tokito, Mariko; Ostap, E. Michael; Holzbaur, Erika L. F.

2014-09-01

Dynactin is an essential cofactor for most cellular functions of the microtubule motor cytoplasmic dynein, but the mechanism by which dynactin activates dynein remains unclear. Here we use single molecule approaches to investigate dynein regulation by the dynactin subunit p150Glued. We investigate the formation and motility of a dynein-p150Glued co-complex using dual-colour total internal reflection fluorescence microscopy. p150Glued recruits and tethers dynein to the microtubule in a concentration-dependent manner. Single molecule imaging of motility in cell extracts demonstrates that the CAP-Gly domain of p150Glued decreases the detachment rate of the dynein-dynactin complex from the microtubule and also acts as a brake to slow the dynein motor. Consistent with this important role, two neurodegenerative disease-causing mutations in the CAP-Gly domain abrogate these functions in our assays. Together, these observations support a model in which dynactin enhances the initial recruitment of dynein onto microtubules and promotes the sustained engagement of dynein with its cytoskeletal track.

49 CFR 238.431 - Brake system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... dynamic brake does not result in exceeding the allowable stopping distance; (2) The friction brake alone... speed for safe operation of the train using only the friction brake portion of the blended brake with no...

49 CFR 238.431 - Brake system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... dynamic brake does not result in exceeding the allowable stopping distance; (2) The friction brake alone... speed for safe operation of the train using only the friction brake portion of the blended brake with no...

49 CFR 238.431 - Brake system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... dynamic brake does not result in exceeding the allowable stopping distance; (2) The friction brake alone... speed for safe operation of the train using only the friction brake portion of the blended brake with no...

Doppler extraction with a digital VCO

NASA Technical Reports Server (NTRS)

Starner, E. R.; Nossen, E. J.

1977-01-01

Digitally controlled oscillator in phased-locked loop may be useful for data communications systems, or may be modified to serve as information extraction component of microwave or optical system for collision avoidance or automatic braking. Instrument is frequency-synthesizing device with output specified precisely by digital number programmed into frequency register.

Behavior of aircraft antiskid braking systems on dry and wet runway surfaces: Hydromechanically controlled system

NASA Technical Reports Server (NTRS)

Tanner, J. A.; Stubbs, S. M.; Smith, E. G.

1981-01-01

The investigation utilized one main gear wheel, brake, and tire assembly of a McDonnell Douglas DC-9 series 10 airplane. The landing-gear strut was replaced by a dynamometer. During maximum braking, average braking behavior indexes based upon brake pressure, brake torque, and drag-force friction coefficient developed by the antiskid system were generally higher on dry surfaces than on wet surfaces. The three braking behavior indexes gave similar results but should not be used interchangeably as a measure of the braking of this antiskid sytem. During the transition from a dry to a flooded surface under heavy braking, the wheel entered into a deep skid but the antiskid system reacted quickly by reducing brake pressure and performed normally during the remainder of the run on the flooded surface. The brake-pressure recovery following transition from a flooded to a dry surface was shown to be a function of the antiskid modulating orifice.

Thermal analysis of disc brakes using finite element method

NASA Astrophysics Data System (ADS)

Jaenudin, Jamari, J.; Tauviqirrahman, M.

2017-01-01

Disc brakes are components of a vehicle that serve to slow or stop the rotation of the wheel. This paper discusses the phenomenon of heat distribution on the brake disc during braking. Heat distribution on the brake disc is caused by kinetic energy changing into mechanical energy. Energy changes occur during the braking process due to friction between the surface of the disc and a disc pad. The temperature resulting from this friction rises high. This thermal analysis on brake discs is aimed to evaluate the performance of an electric car in the braking process. The aim of this study is to analyze the thermal behavior of the brake discs using the Finite Element Method (FEM) through examining the heat distribution on the brake disc using 3-D modeling. Results obtained from the FEM reflect the effects of high heat due to the friction between the disc pad with the disc rotor. Results of the simulation study are used to identify the effect of the heat distribution that occurred during the braking process.

Wheel slip dump valve for railway braking system

NASA Astrophysics Data System (ADS)

Zhang, Xuan; Zhang, LiHao; Li, QingXuan; Shi, YanTao

2017-09-01

As we all know, pneumatic braking system plays an important role in the safety of the whole vehicle. In the anti slip braking system, the pressure of braking cylinder can be adjusted by the quick power response of wheel slip dump valve, so that the lock situation won’t occur during vehicle service. During the braking of railway vehicles, the braking force provided by braking disc reduces vehicle’s speed. But the locking slip will happen due to the oversize of braking force or the reduction of sticking coefficient between wheel and rail. It will cause not only the decline of braking performance but also the increase of braking distance. In the meanwhile, it will scratch the wheel and influence the stable running of vehicles. Now, the speed of passenger vehicle has been increased. In order to shorten the braking distance as far as possible, sticking stickiness must be fully applied. So the occurrence probability of wheel slip is increased.

Rigid Ankle Foot Orthosis Deteriorates Mediolateral Balance Control and Vertical Braking during Gait Initiation

PubMed Central

Delafontaine, Arnaud; Gagey, Olivier; Colnaghi, Silvia; Do, Manh-Cuong; Honeine, Jean-Louis

2017-01-01

Rigid ankle-foot orthoses (AFO) are commonly used for impeding foot drop during the swing phase of gait. They also reduce pain and improve gait kinematics in patients with weakness or loss of integrity of ankle-foot complex structures due to various pathological conditions. However, this comes at the price of constraining ankle joint mobility, which might affect propulsive force generation and balance control. The present study examined the effects of wearing an AFO on biomechanical variables and electromyographic activity of tibialis anterior (TA) and soleus muscles during gait initiation (GI). Nineteen healthy adults participated in the study. They initiated gait at a self-paced speed with no ankle constraint as well as wearing an AFO on the stance leg, or bilaterally. Constraining the stance leg ankle decreased TA activity ipsilaterally during the anticipatory postural adjustment (APA) of GI, and ipsilateral soleus activity during step execution. In the sagittal plane, the decrease in the stance leg TA activity reduced the backward displacement of the center of pressure (CoP) resulting in a reduction of the forward velocity of the center of mass (CoM) measured at foot contact (FC). In the frontal plane, wearing the AFO reduced the displacement of the CoP in the direction of the swing leg during the APA phase. The mediolateral velocity of the CoM increased during single-stance prompting a larger step width to recover balance. During step execution, the CoM vertical downward velocity is normally reduced in order to lessen the impact of the swing leg with the floor and facilitates the rise of the CoM that occurs during the subsequent double-support phase. The reduction in stance leg soleus activity caused by constraining the ankle weakened the vertical braking of the CoM during step execution. This caused the absolute instantaneous vertical velocity of the CoM at FC to be greater in the constrained conditions with respect to the control condition. From a rehabilitation perspective, passively- or actively-powered assistive AFOs could correct for the reduction in muscle activity and enhance balance control during GI of patients. PMID:28503144

49 CFR 571.116 - Standard No. 116; Motor vehicle brake fluids.

Code of Federal Regulations, 2012 CFR

2012-10-01

... cavity or sac on the surface of a brake cup. Brake fluid means a liquid designed for use in a motor... designed for use in motor vehicle hydraulic brake systems in which the fluid is not in contact with... rubber components of brake systems designed for use with DOT brake fluids. (3) KEEP HYDRAULIC SYSTEM...

49 CFR 571.116 - Standard No. 116; Motor vehicle brake fluids.

Code of Federal Regulations, 2013 CFR

2013-10-01

... cavity or sac on the surface of a brake cup. Brake fluid means a liquid designed for use in a motor... designed for use in motor vehicle hydraulic brake systems in which the fluid is not in contact with... rubber components of brake systems designed for use with DOT brake fluids. (3) KEEP HYDRAULIC SYSTEM...

49 CFR 571.116 - Standard No. 116; Motor vehicle brake fluids.

Code of Federal Regulations, 2014 CFR

2014-10-01

... cavity or sac on the surface of a brake cup. Brake fluid means a liquid designed for use in a motor... designed for use in motor vehicle hydraulic brake systems in which the fluid is not in contact with... rubber components of brake systems designed for use with DOT brake fluids. (3) KEEP HYDRAULIC SYSTEM...

Heavy and Overweight Vehicle Brake Testing: Five-Axle Combination Tractor-Flatbed Final Report

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

Lascurain, Mary Beth; Capps, Gary J; Franzese, Oscar

The Federal Motor Carrier Safety Administration, in coordination with the Federal Highway Administration, sponsored the Heavy and Overweight Vehicle Brake Testing (HOVBT) program in order to provide information about the effect of gross vehicle weight (GVW) on braking performance. Because the Federal Motor Carrier Safety Regulations limit the number of braking system defects that may exist for a vehicle to be allowed to operate on the roadways, the examination of the effect of brake defects on brake performance for increased loads is also relevant. The HOVBT program seeks to provide relevant information to policy makers responsible for establishing load limits,more » beginning with providing test data for a combination tractor/trailer. This testing was conducted on a five-axle combination vehicle with tractor brakes meeting the Reduced Stopping Distance requirement rulemaking. This report provides a summary of the testing activities, the results of various analyses of the data, and recommendations for future research. Following a complete brake rebuild, instrumentation, and brake burnish, stopping tests were performed from 20 and 40 mph with various brake application pressures (15 psi, 25 psi, 35 psi, 45 psi, 55 psi, and full system pressure). These tests were conducted for various brake conditions at the following GVWs: 60,000, 80,000, 91,000, 97,000, 106,000, and 116,000 lb. The 80,000-lb GVWs included both balanced and unbalanced loads. The condition of the braking system was also varied. To introduce these defects, brakes (none, forward drive axle, or rear trailer axle) were made inoperative. In addition to the stopping tests, performance-based brake tests were conducted for the various loading and brake conditions. Analysis of the stopping test data showed the stopping distance to increase with load (as expected) and also showed that more braking force was generated by the drive axle brakes than the trailer axle brakes. The constant-pressure stopping test data revealed a linear relationship between brake application pressure and was used to develop an algorithm to normalize stopping data for weight and initial speed.« less

Investigation of Product Performance of Al-Metal Matrix Composites Brake Disc using Finite Element Analysis

NASA Astrophysics Data System (ADS)

Fatchurrohman, N.; Marini, C. D.; Suraya, S.; Iqbal, AKM Asif

2016-02-01

The increasing demand of fuel efficiency and light weight components in automobile sectors have led to the development of advanced material parts with improved performance. A specific class of MMCs which has gained a lot of attention due to its potential is aluminium metal matrix composites (Al-MMCs). Product performance investigation of Al- MMCs is presented in this article, where an Al-MMCs brake disc is analyzed using finite element analysis. The objective is to identify the potentiality of replacing the conventional iron brake disc with Al-MMCs brake disc. The simulation results suggested that the MMCs brake disc provided better thermal and mechanical performance as compared to the conventional cast iron brake disc. Although, the Al-MMCs brake disc dissipated higher maximum temperature compared to cast iron brake disc's maximum temperature. The Al-MMCs brake disc showed a well distributed temperature than the cast iron brake disc. The high temperature developed at the ring of the disc and heat was dissipated in circumferential direction. Moreover, better thermal dissipation and conduction at brake disc rotor surface played a major influence on the stress. As a comparison, the maximum stress and strain of Al-MMCs brake disc was lower than that induced on the cast iron brake disc.

Modelling and validation of magnetorheological brake responses using parametric approach

NASA Astrophysics Data System (ADS)

Z, Zainordin A.; A, Abdullah M.; K, Hudha

2013-12-01

Magnetorheological brake (MR Brake) is one x-by-wire systems which performs better than conventional brake systems. MR brake consists of a rotating disc that is immersed with Magnetorheological Fluid (MR Fluid) in an enclosure of an electromagnetic coil. The applied magnetic field will increase the yield strength of the MR fluid where this fluid was used to decrease the speed of the rotating shaft. The purpose of this paper is to develop a mathematical model to represent MR brake with a test rig. The MR brake model is developed based on actual torque characteristic which is coupled with motion of a test rig. Next, the experimental are performed using MR brake test rig and obtained three output responses known as angular velocity response, torque response and load displacement response. Furthermore, the MR brake was subjected to various current. Finally, the simulation results of MR brake model are then verified with experimental results.

The Application of Vibration Accelerations in the Assessment of Average Friction Coefficient of a Railway Brake Disc

NASA Astrophysics Data System (ADS)

Sawczuk, Wojciech

2017-06-01

Due to their wide range of friction characteristics resulting from the application of different friction materials and good heat dissipation conditions, railway disc brakes have long replaced block brakes in many rail vehicles. A block brake still remains in use, however, in low speed cargo trains. The paper presents the assessment of the braking process through the analysis of vibrations generated by the components of the brake system during braking. It presents a possibility of a wider application of vibroacoustic diagnostics (VA), which aside from the assessment of technical conditions (wear of brake pads) also enables the determination of the changes of the average friction coefficient as a function of the braking onset speed. Vibration signals of XYZ were measured and analyzed. The analysis of the results has shown that there is a relation between the values of the point measures and the wear of the brake pads.

49 CFR 238.15 - Movement of passenger equipment with power brake defects.

Code of Federal Regulations, 2011 CFR

2011-10-01

... passenger equipment containing a power brake defect at the time a Class I or IA brake test is performed... route after a Class I or IA brake test was performed), a commuter or passenger train that has in its consist passenger equipment containing a power brake defect at the time that a Class I or IA brake test...

NAC Off-Vehicle Brake Testing Project

DTIC Science & Technology

2007-05-01

disc pads/rotors and drum shoe assemblies/ drums - Must use vehicle “OEM” brake /hub-end hardware, or ESA... brake component comparison analysis (primary)* - brake system design analysis - brake system component failure analysis - (*) limited to disc pads...e.g. disc pads/rotors, drum shoe assemblies/ drums . - Not limited to “OEM” brake /hub-end hardware as there is none ! - Weight transfer, plumbing,

Braking System for Wind Turbines

NASA Technical Reports Server (NTRS)

Krysiak, J. E.; Webb, F. E.

1987-01-01

Operating turbine stopped smoothly by fail-safe mechanism. Windturbine braking systems improved by system consisting of two large steel-alloy disks mounted on high-speed shaft of gear box, and brakepad assembly mounted on bracket fastened to top of gear box. Lever arms (with brake pads) actuated by spring-powered, pneumatic cylinders connected to these arms. Springs give specific spring-loading constant and exert predetermined load onto brake pads through lever arms. Pneumatic cylinders actuated positively to compress springs and disengage brake pads from disks. During power failure, brakes automatically lock onto disks, producing highly reliable, fail-safe stops. System doubles as stopping brake and "parking" brake.

Brake blending strategy for a hybrid vehicle

DOEpatents

Boberg, Evan S.

2000-12-05

A hybrid electric powertrain system is provided including a transmission for driving a pair of wheels of a vehicle and a heat engine and an electric motor/generator coupled to the transmission. A friction brake system is provided for applying a braking torque to said vehicle. A controller unit generates control signals to the electric motor/generator and the friction brake system for controllably braking the vehicle in response to a drivers brake command. The controller unit determines and amount of regenerative torque available and compares this value to a determined amount of brake torque requested for determining the control signals to the electric motor/generator and the friction brake system.

49 CFR 220.5 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... equipment, or track motor car, singly or in combination with other equipment, on the track of a railroad... systems, electric traction systems, roadway facilities or roadway maintenance machinery on or near track... one or more locomotives coupled with or without cars, requiring an air brake test in accordance with...

Structure Topology Optimization of Brake Pad in Large- megawatt Wind Turbine Brake Considering Thermal- structural Coupling

NASA Astrophysics Data System (ADS)

Zhang, S. F.; Yin, J.; Liu, Y.; Sha, Z. H.; Ma, F. J.

2016-11-01

There always exists severe non-uniform wear of brake pad in large-megawatt wind turbine brake during the braking process, which has the brake pad worn out in advance and even threats the safety production of wind turbine. The root cause of this phenomenon is the non-uniform deformation caused by thermal-structural coupling effect between brake pad and disc while braking under the conditions of both high speed and heavy load. For this problem, mathematical model of thermal-structural coupling analysis is built. Based on the topology optimization method of Solid Isotropic Microstructures with Penalization, SIMP, structure topology optimization of brake pad is developed considering the deformation caused by thermal-structural coupling effect. The objective function is the minimum flexibility, and the structure topology optimization model of brake pad is established after indirect thermal- structural coupling analysis. Compared with the optimization result considering non-thermal- structural coupling, the conspicuous influence of thermal effect on brake pad wear and deformation is proven as well as the rationality of taking thermal-structural coupling effect as optimization condition. Reconstructed model is built according to the result, meanwhile analysis for verification is carried out with the same working condition. This study provides theoretical foundation for the design of high-speed and heavy-load brake pad. The new structure may provide design reference for improving the stress condition between brake pad and disc, enhancing the use ratio of friction material and increasing the working performance of large-megawatt wind turbine brake.

Diagnostics monitor of the braking efficiency in the on board diagnostics system for the motor vehicles

NASA Astrophysics Data System (ADS)

Gajek, Andrzej

2016-09-01

The article presents diagnostics monitor for control of the efficiency of brakes in various road conditions in cars equipped with pressure sensor in brake (ESP) system. Now the brake efficiency of the vehicles is estimated periodically in the stand conditions on the base of brake forces measurement or in the road conditions on the base of the brake deceleration. The presented method allows to complete the stand - periodical tests of the brakes by current on board diagnostics system OBD for brakes. First part of the article presents theoretical dependences between deceleration of the vehicle and brake pressure. The influence of the vehicle mass, initial speed of braking, temperature of brakes, aerodynamic drag, rolling resistance, engine resistance, state of the road surface, angle of the road sloping on the deceleration have been analysed. The manner of the appointed of these parameters has been analysed. The results of the initial investigation have been presented. At the end of the article the strategy of the estimation and signalization of the irregular value of the deceleration are presented.

Phase correlated adequate afferent action potentials as a drive of human spinal oscillators.

PubMed

Schalow, G

1993-12-01

1. By recording, with 2 pairs of wire electrodes, single-fibre action potentials (APs) from lower sacral nerve roots of a brain-dead human and a patient with spinal cord lesion, impulse patterns of afferent APs and impulse trains of oscillatory firing motoneurons could be identified and correlated. 2. Two highly activated secondary muscle spindle afferents increased and decreased their activity at about 0.3 Hz. The duration of the doublet interspike interval of a secondary spindle afferent fibre showed no correlation to the oscillation period of the motoneuron. 3. A continuously oscillatory firing motoneuron innervating the external and sphincter showed more transient breaks with the reduction of the number of phase correlated APs from 2 spindle afferents, indicating a looser oscillation. A transient brake of a 157 msec period alpha 2-oscillation could be correlated to the shift of a interspike interval distribution peak from 150 to 180 msec of the adequate afferent input, which suggests a transient loss of the necessary phase relation. 4. Oscillatory firing alpha 2-motoneurons innervating the external bladder and anal sphincters fired independently according to their phase correlated APs from the urinary bladder stretch receptor and muscle spindle afferents respectively; the bladder motoneuron slightly inhibited the anal motoneuron. 5. Receptors of the afferents and innervation sites of oscillatory firing motoneurons could be located within the urinary tract and the anal canal.

Run-Curve Design for Energy Saving Operation in a Modern DC-Electrification

NASA Astrophysics Data System (ADS)

Koseki, Takafumi; Noda, Takashi

Mechanical brakes are often used by electric trains. These brakes have a few problems like response speed, coefficient of friction, maintenance cost and so on. As a result, methods for actively using regenerative brakes are required. In this paper, we propose the useful pure electric braking, which would involve ordinary brakes by only regenerative brakes without any mechanical brakes at high speed. Benefits of our proposal include a DC-electrification system with regenerative substations that can return powers to the commercial power system and a train that can use the full regenerative braking force. We furthermore evaluate the effects on running time and energies saved by regenerative substations in the proposed method.

Fuzzy logic electric vehicle regenerative antiskid braking and traction control system

DOEpatents

Cikanek, S.R.

1994-10-25

An regenerative antiskid braking and traction control system using fuzzy logic for an electric or hybrid vehicle having a regenerative braking system operatively connected to an electric traction motor, and a separate hydraulic braking system includes sensors for monitoring present vehicle parameters and a processor, responsive to the sensors, for calculating vehicle parameters defining the vehicle behavior not directly measurable by the sensor and determining if regenerative antiskid braking control, requiring hydraulic braking control, and requiring traction control are required. The processor then employs fuzzy logic based on the determined vehicle state and provides command signals to a motor controller to control operation of the electric traction motor and to the brake controller to control fluid pressure applied at each vehicle wheel to provide the appropriate regenerative braking control, hydraulic braking control, and traction control. 123 figs.

Electric vehicle regenerative antiskid braking and traction control system

DOEpatents

Cikanek, S.R.

1995-09-12

An antiskid braking and traction control system for an electric or hybrid vehicle having a regenerative braking system operatively connected to an electric traction motor, and a separate hydraulic braking system includes one or more sensors for monitoring present vehicle parameters and a processor, responsive to the sensors, for calculating vehicle parameters defining the vehicle behavior not directly measurable by the sensors and determining if regenerative antiskid braking control, requiring hydraulic braking control, or requiring traction control are required. The processor then employs a control strategy based on the determined vehicle state and provides command signals to a motor controller to control the operation of the electric traction motor and to a brake controller to control fluid pressure applied at each vehicle wheel to provide the appropriate regenerative antiskid braking control, hydraulic braking control, and traction control. 10 figs.

Electric vehicle regenerative antiskid braking and traction control system

DOEpatents

Cikanek, Susan R.

1995-01-01

An antiskid braking and traction control system for an electric or hybrid vehicle having a regenerative braking system operatively connected to an electric traction motor, and a separate hydraulic braking system includes one or more sensors for monitoring present vehicle parameters and a processor, responsive to the sensors, for calculating vehicle parameters defining the vehicle behavior not directly measurable by the sensors and determining if regenerative antiskid braking control, requiring hydrualic braking control, or requiring traction control are required. The processor then employs a control strategy based on the determined vehicle state and provides command signals to a motor controller to control the operation of the electric traction motor and to a brake controller to control fluid pressure applied at each vehicle wheel to provide the appropriate regenerative antiskid braking control, hydraulic braking control, and traction control.

Fuzzy logic electric vehicle regenerative antiskid braking and traction control system

DOEpatents

Cikanek, Susan R.

1994-01-01

An regenerative antiskid braking and traction control system using fuzzy logic for an electric or hybrid vehicle having a regenerative braking system operatively connected to an electric traction motor, and a separate hydraulic braking system includes sensors for monitoring present vehicle parameters and a processor, responsive to the sensors, for calculating vehicle parameters defining the vehicle behavior not directly measurable by the sensor and determining if regenerative antiskid braking control, requiring hydraulic braking control, and requiring traction control are required. The processor then employs fuzzy logic based on the determined vehicle state and provides command signals to a motor controller to control operation of the electric traction motor and to the brake controller to control fluid pressure applied at each vehicle wheel to provide the appropriate regenerative braking control, hydraulic braking control, and traction control.

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

Tong, H.; Kou, F. F., E-mail: htong_2005@163.com

The coupled evolution of pulsar rotation and inclination angle in the wind braking model is calculated. The oblique pulsar tends to align. The pulsar alignment affects its spin-down behavior. As a pulsar evolves from the magneto-dipole radiation dominated case to the particle wind dominated case, the braking index first increases and then decreases. In the early time, the braking index may be larger than three. During the following long time, the braking index is always smaller than three. The minimum braking index is about one. This can explain the existence of a high braking index larger than three and amore » low braking index simultaneously. The pulsar braking index is expected to evolve from larger than three to about one. The general trend is for the pulsar braking index to evolve from the Crab-like case to the Vela-like case.« less

Evaluation of Squeal Noise from the WMATA Transit Car Disc Brake System : A Preliminary Investigation

DOT National Transportation Integrated Search

1981-03-01

The Washington Metropolitan Area Transit Authority (WMATA) rail transit car design adopted the use of disc brakes as the primary friction braking system. Unfortunately, while disc brakes are more efficient than the traditional tread brake designs, th...

14 CFR 23.735 - Brakes.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Brakes. 23.735 Section 23.735 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... § 23.735 Brakes. (a) Brakes must be provided. The landing brake kinetic energy capacity rating of each...

14 CFR 23.735 - Brakes.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Brakes. 23.735 Section 23.735 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... § 23.735 Brakes. (a) Brakes must be provided. The landing brake kinetic energy capacity rating of each...

14 CFR 23.735 - Brakes.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Brakes. 23.735 Section 23.735 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... § 23.735 Brakes. (a) Brakes must be provided. The landing brake kinetic energy capacity rating of each...

14 CFR 23.735 - Brakes.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Brakes. 23.735 Section 23.735 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... § 23.735 Brakes. (a) Brakes must be provided. The landing brake kinetic energy capacity rating of each...

49 CFR 238.431 - Brake system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... train is operating under worst-case adhesion conditions. (b) The brake system shall be designed to allow... a brake rate consistent with prevailing adhesion, passenger safety, and brake system thermal... adhesion control system designed to automatically adjust the braking force on each wheel to prevent sliding...

CFD Modeling and Simulation of Aeorodynamic Cooling of Automotive Brake Rotor

NASA Astrophysics Data System (ADS)

Belhocien, Ali; Omar, Wan Zaidi Wan

Braking system is one of the important control systems of an automotive. For many years, the disc brakes have been used in automobiles for the safe retarding of the vehicles. During the braking enormous amount of heat will be generated and for effective braking sufficient heat dissipation is essential. The thermal performance of disc brake depends upon the characteristics of the airflow around the brake rotor and hence the aerodynamics is an important in the region of brake components. A CFD analysis is carried out on the braking system as a case study to make out the behavior of airflow distribution around the disc brake components using ANSYS CFX software. We are interested in the determination of the heat transfer coefficient (HTC) on each surface of a ventilated disc rotor varying with time in a transient state using CFD analysis, and then imported the surface film condition data into a corresponding FEM model for disc temperature analysis.

Design and Analysis of a Novel Centrifugal Braking Device for a Mechanical Antilock Braking System.

PubMed

Yang, Cheng-Ping; Yang, Ming-Shien; Liu, Tyng

2015-06-01

A new concept for a mechanical antilock braking system (ABS) with a centrifugal braking device (CBD), termed a centrifugal ABS (C-ABS), is presented and developed in this paper. This new CBD functions as a brake in which the output braking torque adjusts itself depending on the speed of the output rotation. First, the structure and mechanical models of the entire braking system are introduced and established. Second, a numerical computer program for simulating the operation of the system is developed. The characteristics of the system can be easily identified and can be designed with better performance by using this program to studying the effects of different design parameters. Finally, the difference in the braking performance between the C-ABS and the braking system with or without a traditional ABS is discussed. The simulation results indicate that the C-ABS can prevent the wheel from locking even if excessive operating force is provided while still maintaining acceptable braking performance.

Extended-Kalman-filter-based regenerative and friction blended braking control for electric vehicle equipped with axle motor considering damping and elastic properties of electric powertrain

NASA Astrophysics Data System (ADS)

Lv, Chen; Zhang, Junzhi; Li, Yutong

2014-11-01

Because of the damping and elastic properties of an electrified powertrain, the regenerative brake of an electric vehicle (EV) is very different from a conventional friction brake with respect to the system dynamics. The flexibility of an electric drivetrain would have a negative effect on the blended brake control performance. In this study, models of the powertrain system of an electric car equipped with an axle motor are developed. Based on these models, the transfer characteristics of the motor torque in the driveline and its effect on blended braking control performance are analysed. To further enhance a vehicle's brake performance and energy efficiency, blended braking control algorithms with compensation for the powertrain flexibility are proposed using an extended Kalman filter. These algorithms are simulated under normal deceleration braking. The results show that the brake performance and blended braking control accuracy of the vehicle are significantly enhanced by the newly proposed algorithms.

Brake Fluid Compatibility Studies with Advanced Brake Systems

DTIC Science & Technology

2016-01-16

and chemical characterization tests. Increased wear seen with the silicone brake fluid on brake system parts was substantiated by laboratory bench...tests and dynamic seal tests, followed by a series of physical and chemical characterization tests on used silicone brake fluid and hydraulic...elastomers with silicone brake fluid was conducted at ambient and 40 °C, primarily to determine using GC-MS, if the chemical constituents in the

Mechanical Mixer for Rudder/Braking Wedge

NASA Technical Reports Server (NTRS)

Grimm, D.

1985-01-01

Right and left rudder panels moved separately. Mechanical mixer enables panels of two-panel rudder to rotate in same direction for steering or in opposite directions for dynamic braking. Steering and braking inputs separate so any combination of steering and braking motions executed simultaneously. Developed for aerodynamic braking of Space Shuttle orbiter, steering/braking drive train and rudder arrangement used for similar purposes on aircraft, thereby reducing sizes of thrust reversers.

Evaluation of the deposition, translocation and pathological response of brake dust with and without added chrysotile in comparison to crocidolite asbestos following short-term inhalation: Interim results

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

Bernstein, David M., E-mail: davidb@itox.ch; Rogers, Rick, E-mail: rarogers5@yahoo.com; Sepulveda, Rosalina

Chrysotile has been frequently used in the past in manufacturing brakes and continues to be used in brakes in many countries. This study was designed to provide an understanding of the biokinetics and potential toxicology following inhalation of brake dust following short term exposure in rats. The deposition, translocation and pathological response of brake dust derived from brake pads manufactured with chrysotile were evaluated in comparison to the amphibole, crocidolite asbestos. Rats were exposed by inhalation 6 h/day for 5 days to either brake dust obtained by sanding of brake-drums manufactured with chrysotile, a mixture of chrysotile and the brakemore » dust or crocidolite asbestos. No significant pathological response was observed at any time point in either the brake dust or chrysotile/brake dust exposure groups. The long chrysotile fibers (> 20 μm) cleared quickly with T{sub 1/2} estimated as 30 and 33 days, respectively in the brake dust and the chrysotile/brake dust exposure groups. In contrast, the long crocidolite fibers had a T{sub 1/2} > 1000 days and initiated a rapid inflammatory response in the lung following exposure resulting in a 5-fold increase in fibrotic response within 91 days. These results provide support that brake dust derived from chrysotile containing brake drums would not initiate a pathological response in the lung following short term inhalation. - Highlights: • We evaluated brake dust w/wo added chrysotile in comparison to crocidolite asbestos. • Persistence, translocation, pathological response in the lung and pleural cavity. • Chrysotile cleared rapidly from the lung while the crocidolite asbestos persisted. • No significant pathology observed at any time point in the brake-dust groups. • Crocidolite produced pathological response - Wagner 4 interstitial fibrosis by 32d.« less

77 FR 13971 - Regulated Navigation Area; MBTA Saugus River Railroad Drawbridge Rehabilitation Project, Saugus...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-08

.... Wright, Program Manager, Docket Operations, telephone 202-366-9826. SUPPLEMENTARY INFORMATION: Public... MBTA has instituted single track operation, a reduction of speed, and prohibited braking on the bridge... the bridge. The delay of necessary repair operations would result in increased costs, delay the date...

29 CFR 1910.211 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) Antirepeat means the part of the clutch/brake control system designed to limit the press to a single stroke... acting in conjunction, and is used to describe a situation wherein two or more controls exist in an... without intervening stops (or other clutch control action) at the end of individual strokes. (10...

49 CFR 570.54 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... from the driver control to a hydraulic brake system to actuate the service brakes. Electric brake system means a system that uses electric current to actuate the service brake. Vacuum brake system means a system that uses a vacuum and atmospheric pressure for transmitting a force from the driver...

49 CFR 570.54 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... from the driver control to a hydraulic brake system to actuate the service brakes. Electric brake system means a system that uses electric current to actuate the service brake. Vacuum brake system means a system that uses a vacuum and atmospheric pressure for transmitting a force from the driver...

49 CFR 570.54 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

...-hydraulic brake subsystem means a subsystem of the air brake that uses compressed air to transmit a force from the driver control to a hydraulic brake system to actuate the service brakes. Electric brake... a system that uses a vacuum and atmospheric pressure for transmitting a force from the driver...

49 CFR 570.54 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

...-hydraulic brake subsystem means a subsystem of the air brake that uses compressed air to transmit a force from the driver control to a hydraulic brake system to actuate the service brakes. Electric brake... a system that uses a vacuum and atmospheric pressure for transmitting a force from the driver...

49 CFR 570.54 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

...-hydraulic brake subsystem means a subsystem of the air brake that uses compressed air to transmit a force from the driver control to a hydraulic brake system to actuate the service brakes. Electric brake... a system that uses a vacuum and atmospheric pressure for transmitting a force from the driver...

30 CFR 56.10004 - Brakes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Aerial Tramways § 56.10004 Brakes. Positive-action-type brakes and devices which apply the brakes automatically in the event of a power... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Brakes. 56.10004 Section 56.10004 Mineral...

30 CFR 57.10004 - Brakes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Aerial Tramways § 57.10004 Brakes. Positive-action-type brakes and devices which apply the brakes automatically in the event of a power... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Brakes. 57.10004 Section 57.10004 Mineral...

49 CFR 236.701 - Application, brake; full service.

Code of Federal Regulations, 2010 CFR

2010-10-01

... a split reduction in brake pipe pressure at a service rate until maximum brake cylinder pressure is developed. As applied to an automatic or electro-pneumatic brake with speed governor control, an application other than emergency which develops the maximum brake cylinder pressure, as determined by the design of...

78 FR 3363 - Airworthiness Directives; the Boeing Company Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-16

...-mechanical brake flex shaft (short flexshaft) of the thrust reverser actuation system (TRAS). This proposed... the electro-mechanical brake and center drive unit (CDU) cone brake to verify the holding torque, and... describes a functional test of the electro-mechanical brake and CDU cone brake to verify the holding torque...

49 CFR 393.41 - Parking brake system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... system shall, at all times, be capable of being applied by either the driver's muscular effort or by... 49 Transportation 5 2010-10-01 2010-10-01 false Parking brake system. 393.41 Section 393.41... NECESSARY FOR SAFE OPERATION Brakes § 393.41 Parking brake system. (a) Hydraulic-braked vehicles...

49 CFR 393.41 - Parking brake system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... system shall, at all times, be capable of being applied by either the driver's muscular effort or by... 49 Transportation 5 2011-10-01 2011-10-01 false Parking brake system. 393.41 Section 393.41... NECESSARY FOR SAFE OPERATION Brakes § 393.41 Parking brake system. (a) Hydraulic-braked vehicles...

49 CFR 238.431 - Brake system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Brake system. 238.431 Section 238.431... Equipment § 238.431 Brake system. (a) A passenger train's brake system shall be capable of stopping the... train is operating under worst-case adhesion conditions. (b) The brake system shall be designed to allow...

75 FR 15620 - Federal Motor Vehicle Safety Standards; Air Brake Systems

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-30

... fully develop improved brake systems and also to ensure vehicle control and stability while braking... [Docket No. NHTSA 2009-0175] RIN 2127-AK62 Federal Motor Vehicle Safety Standards; Air Brake Systems... Federal motor vehicle safety standard for air brake systems by requiring substantial improvements in...

49 CFR 393.40 - Required brake systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

... subpart. (2) Air brake systems. Buses, trucks and truck-tractors equipped with air brake systems and..., and 393.52 of this subpart. (4) Electric brake systems. Motor vehicles equipped with electric brake..., trucks and truck tractors manufactured on or after March 1, 1975, and trailers manufactured on or after...

49 CFR 383.95 - Restrictions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... applicant either fails the air brake component of the knowledge test, or performs the skills test in a... the skills test and the restriction, air brakes include any braking system operating fully or partially on the air brake principle. (b) Full air brake. (1) If an applicant performs the skills test in a...

49 CFR 238.5 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... next midnight on a given date. Class I brake test means a complete passenger train brake system test... ensure that the air brake system is 100 percent effective. Class IA brake test means a test and... response to train line commands. Class II brake test means a test and inspection (as further specified in...

49 CFR 238.231 - Brake system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... by testing or previous service. (h) Hand brakes and parking brakes. (1) Except for a locomotive that..., and except for MU locomotives, all locomotives shall be equipped with a hand or parking brake that can... locomotives, on locomotives so equipped, the hand or parking brake as well as its parts and connections shall...

Wheel brakes and their application to aircraft

NASA Technical Reports Server (NTRS)

Dowty, G H

1928-01-01

The advantages to be gained from braking have not been ignored, and in the search for a suitable method many schemes have been suggested and tried. Some of the methods discussed in this paper include: 1) increasing the height of the landing gear; 2) air brakes of various forms; 3) sprags on tail skid and axle; and 4) wheel brakes. This report focuses on the design of wheel brakes and wheel brake controls.

Adaptive controller for regenerative and friction braking system

DOEpatents

Davis, R.I.

1990-10-16

A regenerative and friction braking system for a vehicle having one or more road wheels driven by an electric traction motor includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the road wheels of the vehicle. A system according to this invention further includes control means for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the road wheels of the vehicle without skidding or slipping will not be exceeded. 8 figs.

Adaptive controller for regenerative and friction braking system

DOEpatents

Davis, Roy I.

1990-01-01

A regenerative and friction braking system for a vehicle having one or more roadwheels driven by an electric traction motor includes a driver responsive device for producing a brake demand signal having a magnitude corresponding to the level of braking force selected by the driver and friction and regenerative brakes operatively connected with the roadwheels of the vehicle. A system according to this invention further includes control means for operating the friction and regenerative braking subsystems so that maximum brake torques sustainable by the roadwheels of the vehicle without skidding or slipping will not be exceeded.

Optimal design for slip deceleration control in anti-lock braking system

NASA Astrophysics Data System (ADS)

Mishra, Sheelam; Kumar, Pankaj; Rahman, Mohd. Saifur

2018-05-01

ABS (Anti-lock Braking System) is the most advanced braking system implemented in modern cars to avoid the slipping or skidding of the vehicle on the road. Moreover, it reduces the stopping distance of the vehicle because it avoids the locking of the wheel during braking. It enables the driver to steer the vehicle during braking. But every system has its downsides and likewise ABS too, it is not efficient during normal braking or snowy conditions. Our aim is to overcome these downsides and optimize Anti-lock Braking System to make it even better.

Study on antilock brake system with elastic membrane vibration generated by controlled solenoid excitation

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

Wibowo,, E-mail: wibowo-uns@yahoo.com; Zakaria,, E-mail: zakaaria27@gmail.com; Lambang, Lullus, E-mail: lulus-l@yahoo.com

The most effective chassis control system for improving vehicle safety during severe braking is anti-lock braking system (ABS). Antilock effect can be gained by vibrate the pad brake at 7 to 20 cycle per second. The aim of this study is to design a new method of antilock braking system with membrane elastic vibrated by solenoid. The influence of the pressure fluctuations of brake fluid is investigated. Vibration data is collected using a small portable accelerometer-slam stick. The experiment results that the vibration of brake pad caused by controlled solenoid excitation at 10 Hz is obtained by our new method. Themore » result of measurements can be altered by varying brake fluid pressure.« less

Study on antilock brake system with elastic membrane vibration generated by controlled solenoid excitation

NASA Astrophysics Data System (ADS)

Wibowo, Zakaria, Lambang, Lullus; Triyono, Muhayat, Nurul

2016-03-01

The most effective chassis control system for improving vehicle safety during severe braking is anti-lock braking system (ABS). Antilock effect can be gained by vibrate the pad brake at 7 to 20 cycle per second. The aim of this study is to design a new method of antilock braking system with membrane elastic vibrated by solenoid. The influence of the pressure fluctuations of brake fluid is investigated. Vibration data is collected using a small portable accelerometer-slam stick. The experiment results that the vibration of brake pad caused by controlled solenoid excitation at 10 Hz is obtained by our new method. The result of measurements can be altered by varying brake fluid pressure.

Design and testing of a rotational brake with shear thickening fluids

NASA Astrophysics Data System (ADS)

Tian, Tongfei; Nakano, Masami

2017-03-01

A rotational brake working with shear thickening fluid (STF) was designed and tested in this study. With the optimisation in design, most of the STF in the brake can receive the same shear rate when the brake rotates. The parts of this brake were fabricated with a 3D printer and then assembled manually. Three types of STFs with various carrier fluids and different particles were fabricated and tested with a rheometer. Then the brake with each STF was separately tested with the rheometer. The estimated and measured torques as a function of the angular velocity fit each other well. The stability of the rotational STF brake was investigated in repeated tests, which proved the function of the brake for a long time.

Research on motor braking-based DYC strategy for distributed electric vehicle

NASA Astrophysics Data System (ADS)

Zhang, Jingming; Liao, Weijie; Chen, Lei; Cui, Shumei

2017-08-01

In order to bring into full play the advantages of motor braking and enhance the handling stability of distributed electric vehicle, a motor braking-based direct yaw moment control (DYC) strategy was proposed. This strategy could identify whether a vehicle has under-steered or overs-steered, to calculate the direct yaw moment required for vehicle steering correction by taking the corrected yaw velocity deviation and slip-angle deviation as control variables, and exert motor braking moment on the target wheels to perform correction in the manner of differential braking. For validation of the results, a combined simulation platform was set up finally to simulate the motor braking control strategy proposed. As shown by the results, the motor braking-based DYC strategy timely adjusted the motor braking moment and hydraulic braking moment on the target wheels, and corrected the steering deviation and sideslip of the vehicle in unstable state, improving the handling stability.

Creation of operation algorithms for combined operation of anti-lock braking system (ABS) and electric machine included in the combined power plant

NASA Astrophysics Data System (ADS)

Bakhmutov, S. V.; Ivanov, V. G.; Karpukhin, K. E.; Umnitsyn, A. A.

2018-02-01

The paper considers the Anti-lock Braking System (ABS) operation algorithm, which enables the implementation of hybrid braking, i.e. the braking process combining friction brake mechanisms and e-machine (electric machine), which operates in the energy recovery mode. The provided materials focus only on the rectilinear motion of the vehicle. That the ABS task consists in the maintenance of the target wheel slip ratio, which depends on the tyre-road adhesion coefficient. The tyre-road adhesion coefficient was defined based on the vehicle deceleration. In the course of calculated studies, the following operation algorithm of hybrid braking was determined. At adhesion coefficient ≤0.1, driving axle braking occurs only due to the e-machine operating in the energy recovery mode. In other cases, depending on adhesion coefficient, the e-machine provides the brake torque, which changes from 35 to 100% of the maximum available brake torque. Virtual tests showed that values of the wheel slip ratio are close to the required ones. Thus, this algorithm makes it possible to implement hybrid braking by means of the two sources creating the brake torque.

Effects of working memory load and repeated scenario exposure on emergency braking performance.

PubMed

Engström, Johan; Aust, Mikael Ljung; Viström, Matias

2010-10-01

The objective of the present study was to examine the effect of working memory load on drivers' responses to a suddenly braking lead vehicle and whether this effect (if any) is moderated by repeated scenario exposure. Several experimental studies have found delayed braking responses to lead vehicle braking events during concurrent performance of nonvisual, working memory-loading tasks, such as hands-free phone conversation. However, the common use of repeated, and hence somewhat expected, braking events may undermine the generalizability of these results to naturalistic, unexpected, emergency braking scenarios. A critical lead vehicle braking scenario was implemented in a fixed-based simulator.The effects of working memory load and repeated scenario exposure on braking performance were examined. Brake response time was decomposed into accelerator pedal release time and accelerator-to-brake pedal movement time. Accelerator pedal release times were strongly reduced with repeated scenario exposure and were delayed by working memory load with a small but significant amount (178 ms).The two factors did not interact. There were no effects on accelerator-to-brake pedal movement time. The results suggest that effects of working memory load on response performance obtained from repeated critical lead vehicle braking scenarios may be validly generalized to real world unexpected events. The results have important implications for the interpretation of braking performance in experimental settings, in particular in the context of safety-related evaluation of in-vehicle information and communication technologies.

Advanced Natural Gas Reciprocating Engine(s)

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

Pike, Edward

The objective of the Cummins ARES program, in partnership with the US Department of Energy (DOE), is to develop advanced natural gas engine technologies that increase engine system efficiency at lower emissions levels while attaining lower cost of ownership. The goals of the project are to demonstrate engine system achieving 50% Brake Thermal Efficiency (BTE) in three phases, 44%, 47% and 50% (starting baseline efficiency at 36% BTE) and 0.1 g/bhp-hr NOx system out emissions (starting baseline NOx emissions at 2 – 4 g/bhp-hr NOx). Primary path towards above goals include high Brake Mean Effective Pressure (BMEP), improved closed cyclemore » efficiency, increased air handling efficiency and optimized engine subsystems. Cummins has successfully demonstrated each of the phases of this program. All targets have been achieved through application of a combined set of advanced base engine technologies and Waste Heat Recovery from Charge Air and Exhaust streams, optimized and validated on the demonstration engine and other large engines. The following architectures were selected for each Phase: Phase 1: Lean Burn Spark Ignited (SI) Key Technologies: High Efficiency Turbocharging, Higher Efficiency Combustion System. In production on the 60/91L engines. Over 500MW of ARES Phase 1 technology has been sold. Phase 2: Lean Burn Technology with Exhaust Waste Heat Recovery (WHR) System Key Technologies: Advanced Ignition System, Combustion Improvement, Integrated Waste Heat Recovery System. Base engine technologies intended for production within 2 to 3 years Phase 3: Lean Burn Technology with Exhaust and Charge Air Waste Heat Recovery System Key Technologies: Lower Friction, New Cylinder Head Designs, Improved Integrated Waste Heat Recovery System. Intended for production within 5 to 6 years Cummins is committed to the launch of next generation of large advanced NG engines based on ARES technology to be commercialized worldwide.« less

Architecture and Integration Requirements for an ULCE (Unified Life Cycle Engineering) Design Environment.

DTIC Science & Technology

1988-04-01

Locate brake lines on rear side of the gear structure to prevent damage. * Provide emergency brake system , independent of the normal system , and capable of...stopping the aircraft in the same distance as the normal system . -.. * Consider brake temperature in calculating brake energy capability. * Install a...and takeoff. In addition, assume a brake nearing the end of its recommended life. - Antiskid systems shall be as reliable as the rest of the braking

Design and fabrication of advanced materials from Illinois coal wastes. Quarterly report, 1 December 1994--28 February 1995

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

Malhotra, V.M.; Wright, M.A.

1995-12-31

The main goal of this project is to develop a bench-scale procedure to design and fabricate advanced brake and structural composite materials from Illinois coal combustion residues. During the first two quarters of the project, the thrust of the work directed towards characterizing the various coal combustion residues and FGD residue, i.e., scrubber sludge. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC), differential thermal analysis (DTA), and transmission-Fourier transform infrared (FTIR) were conducted on PCC fly ash (Baldwin), FBC fly ash (ADK unit l-6), FBC fly ash (S.I. coal), FBC spent bed ash (ADM, unit l-6), bottom ash, and scrubbermore » sludge (CWLP) residues to characterize their geometrical shapes, mineral phases, and thermal stability. Our spectroscopic results indicate that the scrubber sludge is mainly composed of a gypsum-like phase whose lattice structure is different from the lattice structure of conventional gypsum, and sludge does not contain hannebachite (CaSO{sub 3}.0.5H{sub 2}O) phase. Our attempts to fabricate brake frictional shoes, in the form of 1.25 inch disks, from PCC fly ash, FBC spent bed ash, scrubber sludge, coal char, iron particles, and coal tar were successful. Based on the experience gained and microscopic analyses, we have now upscaled our procedures to fabricate 2.5 inch diameter disk,- from coal combustion residues. This has been achieved. The SEM and Young`s modulus analyses of brake composites fabricated at 400 psi < Pressure < 2200 psi suggest pressure has a strong influence on the particle packing and the filling of interstices in our composites. Also, these results along with mechanical behavior of the fabricated disks lead us to believe that the combination of surface altered PCC fly ash and scrubber sludge particles, together ed ash particles are ideal for our composite materials.« less

Validity of a device designed to measure braking power in bicycle disc brakes.

PubMed

Miller, Matthew C; Fink, Philip W; Macdermid, Paul William; Perry, Blake G; Stannard, Stephen R

2017-07-21

Real-world cycling performance depends not only on exercise capacities, but also on efficiently traversing the bicycle through the terrain. The aim of this study was to determine if it was possible to quantify the braking done by a cyclist in the field. One cyclist performed 408 braking trials (348 on a flat road; 60 on a flat dirt path) over 5 days on a bicycle fitted with brake torque and angular velocity sensors to measure brake power. Based on Newtonian physics, the sum of brake work, aerodynamic drag and rolling resistance was compared with the change in kinetic energy in each braking event. Strong linear relationships between the total energy removed from the bicycle-rider system through braking and the change in kinetic energy were observed on the tar-sealed road (r 2  = 0.989; p < 0.0001) and the dirt path (r 2  = 0.952; p < 0.0001). T-tests revealed no difference between the total energy removed and the change in kinetic energy on the road (p = 0.715) or dirt (p = 0.128). This study highlights that brake torque and angular velocity sensors are valid for calculating brake power on the disc brakes of a bicycle in field conditions. Such a device may be useful for investigating cyclists' ability to traverse through various terrains.

49 CFR 393.49 - Control valves for brakes.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., which is equipped with power brakes, must have the braking system so arranged that one application valve must when activated cause all of the service brakes on the motor vehicle or combination motor vehicle... with an additional valve to be used to operate the brakes on a trailer or trailers or as required for...

77 FR 63712 - Airworthiness Directives; Piaggio Aero Industries S.p.A.

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-17

... authority for Italy. We issued that AD to prevent the brake hydraulic fluid from leaking because of the brake assembly rods contacting the brake valve tubing, which could result in the inability to adequately... brake pads between pilot and copilot, a brake system rod was found deflected. The rod, in this bent...

49 CFR 393.45 - Brake tubing and hoses; hose assemblies and end fittings.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 5 2013-10-01 2013-10-01 false Brake tubing and hoses; hose assemblies and end... assemblies and end fittings. (a) General construction requirements for tubing and hoses, assemblies, and end fittings. All brake tubing and hoses, brake hose assemblies, and brake hose end fittings must meet the...

49 CFR 393.45 - Brake tubing and hoses; hose assemblies and end fittings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 5 2011-10-01 2011-10-01 false Brake tubing and hoses; hose assemblies and end... assemblies and end fittings. (a) General construction requirements for tubing and hoses, assemblies, and end fittings. All brake tubing and hoses, brake hose assemblies, and brake hose end fittings must meet the...

49 CFR 393.45 - Brake tubing and hoses; hose assemblies and end fittings.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 5 2014-10-01 2014-10-01 false Brake tubing and hoses; hose assemblies and end... assemblies and end fittings. (a) General construction requirements for tubing and hoses, assemblies, and end fittings. All brake tubing and hoses, brake hose assemblies, and brake hose end fittings must meet the...

Brakes. Auto Mechanics Curriculum Guide. Module 6. Instructor's Guide.

ERIC Educational Resources Information Center

Allain, Robert

This module is the sixth of nine modules in the competency-based Missouri Auto Mechanics Curriculum Guide. Eight units cover: introduction to automotive brake systems; disc and drum brake system components and how they operate; properties of brake fluid and procedures for bleeding the brake system; diagnosing and determining needed repairs on…

49 CFR 570.55 - Hydraulic brake system.

Code of Federal Regulations, 2011 CFR

2011-10-01

... under a 125-pound force applied to the brake pedal and by no illumination of the brake system failure indicator lamp. The brake system shall withstand the application of force to the pedal without failure of... with power brake systems and the ignition turned to “on” in other vehicles, apply a force of 125 pounds...

49 CFR 570.55 - Hydraulic brake system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... under a 125-pound force applied to the brake pedal and by no illumination of the brake system failure indicator lamp. The brake system shall withstand the application of force to the pedal without failure of... with power brake systems and the ignition turned to “on” in other vehicles, apply a force of 125 pounds...

49 CFR 570.55 - Hydraulic brake system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... under a 125-pound force applied to the brake pedal and by no illumination of the brake system failure indicator lamp. The brake system shall withstand the application of force to the pedal without failure of... with power brake systems and the ignition turned to “on” in other vehicles, apply a force of 125 pounds...

49 CFR 570.55 - Hydraulic brake system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... under a 125-pound force applied to the brake pedal and by no illumination of the brake system failure indicator lamp. The brake system shall withstand the application of force to the pedal without failure of... with power brake systems and the ignition turned to “on” in other vehicles, apply a force of 125 pounds...

49 CFR 570.55 - Hydraulic brake system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... under a 125-pound force applied to the brake pedal and by no illumination of the brake system failure indicator lamp. The brake system shall withstand the application of force to the pedal without failure of... with power brake systems and the ignition turned to “on” in other vehicles, apply a force of 125 pounds...

Gravitational wave emission by the high braking index pulsar PSR J1640-4631

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

De Araujo, José C.N.; Coelho, Jaziel G.; Costa, Cesar A., E-mail: jcarlos.dearaujo@inpe.br, E-mail: jaziel.coelho@inpe.br, E-mail: cesar.costa@inpe.br

Recently, a braking index for the pulsar PSR J1640-4631 has been measured. With a braking index of n = 3.15 ± 0.03, this pulsar has the highest braking index ever measured. As it is well known, a pure magnetic dipole brake yields n = 3, whereas a pure gravitational wave (GW) brake yields n = 5. Therefore, each of these mechanisms alone can not account for the braking index found for PSR J1640-4631. Here we consider in detail that such a braking index could be accounted for if the spindown model combines magnetic dipole and GW brakes. Then, we brieflymore » discuss the detectability of this pulsar by aLIGO and the planned Einstein Telescope. In particular, we show that the amplitude of the GW that comes from our model is around a factor four lower than the amplitude modeled exclusively by GW energy loss. Another interesting outcome of our modeling is that it is possible to obtain the ellipticity from the braking index and other pulsar parameters.« less

Backup Mechanical Brake System of the Wind Turbine

NASA Astrophysics Data System (ADS)

Sirotkin, E. A.; Solomin, E. V.; Gandzha, S. A.; Kirpichnikova, I. M.

2018-01-01

Paper clarifies the necessity of the emergency mechanical brake systems usage for wind turbines. We made a deep analysis of the wind turbine braking methods available on the market, identifying their strengths and weaknesses. The electromechanical braking appeared the most technically reasonable and economically attractive. We described the developed combined electromechanical brake system for vertical axis wind turbine driven from electric drive with variable torque enough to brake over the turbine even on the storm wind speed up to 45 m/s. The progress was made due to the development of specific kinematic brake system diagram and intelligent control system managed by special operation algorithm.

Aircraft Rollout Iterative Energy Simulation

NASA Technical Reports Server (NTRS)

Kinoshita, L.

1986-01-01

Aircraft Rollout Iterative Energy Simulation (ARIES) program analyzes aircraft-brake performance during rollout. Simulates threedegree-of-freedom rollout after nose-gear touchdown. Amount of brake energy dissipated during aircraft landing determines life expectancy of brake pads. ARIES incorporates brake pressure, actual flight data, crosswinds, and runway characteristics to calculate following: brake energy during rollout for up to four independent brake systems; time profiles of rollout distance, velocity, deceleration, and lateral runway position; and all aerodynamic moments on aircraft. ARIES written in FORTRAN 77 for batch execution.

76 FR 8919 - Airworthiness Directives; DASSAULT AVIATION Model MYSTERE-FALCON 50 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-02-16

... of the emergency brake system 2 located near the nose landing gear bearing were swapped. The swapping of these two pipes implies that when the Left Hand (LH) brake pedal is depressed, the Right Hand (RH) brake unit is activated, and conversely, when the RH brake pedal is depressed, the LH brake unit is...

49 CFR 232.217 - Train brake tests conducted using yard air.

Code of Federal Regulations, 2010 CFR

2010-10-01

... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... potential overcharge conditions to the train brake system are avoided, the yard air test device may be... section, when yard air is used the train air brake system must be charged and tested as prescribed by...

76 FR 27880 - Airworthiness Directives; DASSAULT AVIATION Model MYSTERE-FALCON 50 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-13

... pipes of the emergency brake system 2 located near the nose landing gear bearing were swapped. The swapping of these two pipes implies that when the Left Hand (LH) brake pedal is depressed, the Right Hand (RH) brake unit is activated, and conversely, when the RH brake pedal is depressed, the LH brake unit...

Study of the dynamic of motion landing vehicles in the planet's atmosphere using inflatable braking device

NASA Astrophysics Data System (ADS)

Koryanov, Vsevolod; Harri, Ari-Matti; Kazakovtcev, Victor

At present paper analyzes the dynamics of movement of the landing vehicle (LV) with an inflatable braking device (IBD). During the movement in the planet's atmosphere with LV with IBD are significant aerodynamic loads, which can lead to a change in a non-rigid shape and appearance of the shell IBD current asymmetries LV with IBD. The presence arising in the manufacture of structural LV asymmetry results in a stabilized descent in the process of turning the LV with IBD various dynamic phenomena, such as the vibrational-rotational resonance, the resonance autorotation, altering the dynamics of angular motion of the LV. As a result of work carried out, among others, the following conclusions: 1. In the first step of descent of landing vehicle possible high angles of attack, however, the very small quantities of the velocity head. 2. In the second phase of descent arise spatial angles of attack, caused by small structural asymmetries of LV. These angles of attack, together with increasing magnitude of the velocity head cause these significant increase in lateral load. The increase in the transverse load leads to an increase in the asymmetry of the external form, which causes an additional increase in the spatial angle of attack. Depending on the magnitude of the transverse stiffness IBD or leads to a certain additional increase in the spatial angle of attack, or a possible buckling landing vehicle. 3. In the third (final) stage of the descent at subsonic speed landing vehicle with additional inflatable braking device does not influence the stiffness braking, changing the dynamics of angular motion slightly. This is due to the small size of the ram on the subsonic long trajectory and, accordingly, small deformation additional inflatable braking device. This research was supported by the European Commission Seventh Framework Programme FP7/2007-2013 under grant agreement n 263255 RITD.

Braking system for use with an arbor of a microscope

DOEpatents

Norgren, Duane U.

1984-01-01

A balanced braking system comprising a plurality of braking assemblies located about a member to be braked. Each of the braking assemblies consists of a spring biased piston of a first material fitted into a body of a different material which has a greater contraction upon cooling than the piston material. The piston is provided with a recessed head portion over which is positioned a diaphragm and forming a space therebetween to which is connected a pressurized fluid supply. The diaphragm is controlled by the fluid in the space to contact or withdraw from the member to be braked. A cooling device causes the body within which the piston is fitted to contract more than the piston, producing a tight shrink fit therebetween. The braking system is particularly applicable for selectively braking an arbor of an electron microscope which immobilizes, for example, a vertically adjustable low temperature specimen holder during observation. The system provides balanced braking forces which can be easily removed and re-established with minimal disturbance to arbor location.

Braking system

DOEpatents

Norgren, D.U.

1982-09-23

A balanced braking system comprising a plurality of braking assemblies located about a member to be braked. Each of the braking assemblies consists of a spring biased piston of a first material fitted into a body of a different material which has a greater contraction upon cooling than the piston material. The piston is provided with a recessed head portion over which is positioned a diaphragm and forming a space therebetween to which is connected a pressurized fluid supply. The diaphragm is controlled by the fluid in the space to contact or withdraw from the member to be braked. A cooling means causes the body within which the piston is fitted to contract more than the piston, producing a tight shrink fit therebetween. The braking system is particularly applicable for selectively braking an arbor of an electron microscope which immobilizes, for example, a vertically adjustable low temperature specimen holder during observation. The system provides balanced braking forces which can be easily removed and re-established with minimal disturbance to arbor location.

Influence of impact speed on head and brain injury outcome in vulnerable road user impacts to the car hood.

PubMed

Fredriksson, Rikard; Zhang, Liying; Boström, Ola; Yang, King

2007-10-01

EuroNCAP and regulations in Europe and Japan evaluate the pedestrian protection performance of cars. The test methods are similar and they all have requirements for the passive protection of the hood area at a pedestrian to car impact speed of 40 km/h. In Europe, a proposal for a second phase of the regulation mandates a brake-assist system along with passive requirements. The system assists the driver in optimizing the braking performance during panic braking, resulting in activation only when the driver brakes sufficiently. In a European study this was estimated to occur in about 50% of pedestrian accidents. A future system for brake assistance will likely include automatic braking, in response to a pre-crash sensor, to avoid or mitigate injuries of vulnerable road users. An important question is whether these systems will provide sufficient protection, or if a parallel, passive pedestrian protection system will be necessary. This study investigated the influence of impact speed on head and brain injury risk, in impacts to the carhood. One car model was chosen and a rigid adjustable plate was mounted under the hood. Free-flying headform impacts were carried out at 20 and 30 km/h head impact velocities at different under-hood distances, 20 to 100 mm; and were compared to earlier tests at 40 km/h. The EEVC WG17 adult pedestrian headform was used for non-rotating tests and a Hybrid III adult 50th percentile head was used for rotational tests where linear and rotational acceleration was measured. Data from the rotational tests was used as input to a validated finite element model of the human head, the Wayne State University Head Injury Model (WSUHIM). The model was utilized to assess brain injury risk and potential injury mechanism in a pedestrian-hood impact. Although this study showed that it was not necessarily true that a lower HIC value reduced the risk for brain injury, it appeared, for the tested car model, under-hood distances of 60 mm in 20 km/h and 80 mm in 30 km/h reduced head injury values for both skull fractures and brain injuries. An earlier study showed that the corresponding value for a test speed of 40 km/h is 100 mm. A 10 km/h reduction in head impact velocity, as in automatic braking, allowed 20 mm less under-hood clearance with maintained head protection of the vulnerable road user.

Design and analysis of an MR rotary brake for self-regulating braking torques.

PubMed

Yun, Dongwon; Koo, Jeong-Hoi

2017-05-01

This paper presents a novel Magneto-rheological (MR) brake system that can self-regulate the output braking torques. The proposed MR brake can generate a braking torque at a critical rotation speed without an external power source, sensors, or controllers, making it a simple and cost-effective device. The brake system consists of a rotary disk, permanent magnets, springs, and MR fluid. The permanent magnets are attached to the rotary disk via the springs, and they move outward through grooves with two different gap distances along the radial direction of the stator due to the centrifugal force. Thus, the position of the magnets is dependent on the spin speed, and it can determine the magnetic fields applied to MR fluids. Proper design of the stator geometry gives the system unique torque characteristics. To show the performance of an MR brake system, the electromagnetic characteristics of the system are analyzed, and the torques generated by the brake are calculated using the result of the electromagnetic analysis. Using a baseline model, a parametric study is conducted to investigate how the design parameters (geometric shapes and material selection) affect the performance of the brake system. After the simulation study, a prototype brake system is constructed and its performance is experimentally evaluated. The experimental results show that the prototype produced the maximum torque of 1.2 N m at the rotational speed of 100 rpm. The results demonstrate the feasibility of the proposed MR brake as a speed regulator in rotating systems.

Electronic Asymmetry by Compositionally Braking Inversion Symmetry

NASA Astrophysics Data System (ADS)

Warusawithana, Maitri

2005-03-01

By stacking molecular layers of 3 different perovskite titanate phases, BaTiO3, SrTiO3 and CaTiO3 with atomic layer control, we construct nanostructures where global inversion symmetry is broken. With the structures clamped to the substrate, the stacking order gives rise to asymmetric strain fields. The dielectric response show asymmetric field tuning consistent with the symmetry of the stacking order. By analyzing the temperature and frequency dependence of the complex dielectric constant, we show that the response comes from activated switching of dipoles between two asymmetric states separated by an energy barrier. We find the size of average dipole units from the temperature dependence of the linewidth of field tuning curves to be around 10 unit cells in all the different nanostructures we investigate. At low temperatures we observe a deviation from the kinetic response suggesting a further growth in correlations. Pyrocurrent measurements confirm this observation indicating a phase transition to a ferro-like state. We explain the high temperature dipoles as single unit cell cross sectional columns correlated via the strain fields in the stacking direction, with the height somewhat short of the film thickness possibly due to some form of weak disorder.

Asbestos Workshop: Sampling, Analysis, and Risk Assessment

DTIC Science & Technology

2012-03-01

coatings Vinyl/asbestos floor tile Automatic transmission components Clutch facings Disc brake pads Drum brake linings Brake blocks Commercial and...A naturally-occurring pliant and fibrous mineral with heat-resistant properties • Serpentine Class: joint compound,‘popcorn’ceilings, brake pads...fabrics, and is used in fire-resistant and insulating materials such as brake linings. The asbestos minerals include chrysotile (white asbestos) and

75 FR 22710 - Airworthiness Directives; BAE Systems (Operations) Limited Model BAe 146-100A and -200A Series...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-30

... aerodynamic braking and to dump lift to ensure that the wheel brakes can provide the necessary speed reduction... the wheel brakes can provide the necessary speed reduction. A review of the changing operational... on landing to provide aerodynamic braking and to dump lift to ensure that the wheel brakes can...

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.

Code of Federal Regulations, 2014 CFR

2014-10-01

... current, and which may include a non-electrical source of power designed to charge batteries and... dissipating electrical energy. Skid number means the frictional resistance of a pavement measured in..., designed so that a single failure in any subsystem (such as a leakage-type failure of a pressure component...

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... current, and which may include a non-electrical source of power designed to charge batteries and... dissipating electrical energy. Skid number means the frictional resistance of a pavement measured in..., designed so that a single failure in any subsystem (such as a leakage-type failure of a pressure component...

49 CFR 571.105 - Standard No. 105; Hydraulic and electric brake systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... current, and which may include a non-electrical source of power designed to charge batteries and... dissipating electrical energy. Skid number means the frictional resistance of a pavement measured in..., designed so that a single failure in any subsystem (such as a leakage-type failure of a pressure component...

76 FR 55829 - Federal Motor Vehicle Safety Standards; Electronic Stability Control Systems

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-09

.... Benefits of ESC Electronic stability control (ESC) systems use automatic computer- controlled braking of... demonstrated that these systems reduce fatal single-vehicle crashes of passenger cars by 55 percent and fatal... potential to prevent 56 percent of the fatal passenger car rollovers and 74 percent of the fatal LTV first...

A parametric study of golf car and personal transport vehicle braking stability and their deficiencies.

PubMed

Seluga, Kristopher J; Baker, Lowell L; Ojalvo, Irving U

2009-07-01

This paper describes research and parametric analyses of braking effectiveness and directional stability for golf cars, personal transport vehicles (PTVs) and low speed vehicles (LSVs). It is shown that current designs, which employ brakes on only the rear wheels, can lead to rollovers if the brakes are applied while traveling downhill. After summarizing the current state of existing safety standards and brake system designs, both of which appear deficient from a safety perspective, a previously developed dynamic simulation model is used to identify which parameters have the greatest influence on the vehicles' yaw stability. The simulation results are then used to parametrically quantify which combination of these factors can lead to yaw induced rollover during hard braking. Vehicle velocity, steering input, path slope and tire friction are all identified as important parameters in determining braking stability, the effects of which on rollover propensity are presented graphically. The results further show that when vehicles are equipped with front brakes or four-wheel brakes, the probability of a yaw induced rollover is almost entirely eliminated. Furthermore, the parametric charts provided may be used as an aid in developing guidelines for golf car and PTV path design if rear brake vehicles are used.

Evaluation of materials and design modifications for aircraft brakes

NASA Technical Reports Server (NTRS)

Ho, T. L.; Kennedy, F. E.; Peterson, M. B.

1975-01-01

A test program is described which was carried out to evaluate several proposed design modifications and several high-temperature friction materials for use in aircraft disk brakes. The evaluation program was carried out on a specially built test apparatus utilizing a disk brake and wheel half from a small het aircraft. The apparatus enabled control of brake pressure, velocity, and braking time. Tests were run under both constant and variable velocity conditions and covered a kinetic energy range similar to that encountered in aircraft brake service. The results of the design evaluation program showed that some improvement in brake performance can be realized by making design changes in the components of the brake containing friction material. The materials evaluation showed that two friction materials show potential for use in aircraft disk brakes. One of the materials is a nickel-based sintered composite, while the other is a molybdenum-based material. Both materials show much lower wear rates than conventional copper-based materials and are better able to withstand the high temperatures encountered during braking. Additional materials improvement is necessary since both materials show a significant negative slope of the friction-velocity curve at low velocities.

EEG-Based Detection of Braking Intention Under Different Car Driving Conditions

PubMed Central

Hernández, Luis G.; Mozos, Oscar Martinez; Ferrández, José M.; Antelis, Javier M.

2018-01-01

The anticipatory recognition of braking is essential to prevent traffic accidents. For instance, driving assistance systems can be useful to properly respond to emergency braking situations. Moreover, the response time to emergency braking situations can be affected and even increased by different driver's cognitive states caused by stress, fatigue, and extra workload. This work investigates the detection of emergency braking from driver's electroencephalographic (EEG) signals that precede the brake pedal actuation. Bioelectrical signals were recorded while participants were driving in a car simulator while avoiding potential collisions by performing emergency braking. In addition, participants were subjected to stress, workload, and fatigue. EEG signals were classified using support vector machines (SVM) and convolutional neural networks (CNN) in order to discriminate between braking intention and normal driving. Results showed significant recognition of emergency braking intention which was on average 71.1% for SVM and 71.8% CNN. In addition, the classification accuracy for the best participant was 80.1 and 88.1% for SVM and CNN, respectively. These results show the feasibility of incorporating recognizable driver's bioelectrical responses into advanced driver-assistance systems to carry out early detection of emergency braking situations which could be useful to reduce car accidents. PMID:29910722

Effects of cryogenic treatment on the wear properties of brake discs

NASA Astrophysics Data System (ADS)

Nadig, D. S.; Shivakumar, P.; Anoop, S.; Chinmay, Kulkarni; Divine, P. V.; Harsha, H. P.

2017-02-01

Disc brakes are invariably used in all the automobiles either to reduce the rotational speed of the wheel or to hold the vehicle stationary. During the braking action, the kinetic energy is converted into heat which can result in high temperatures resulting in fading of brake effects. Brake discs produced out of martensite stainless steel (SS410) are expected to exhibit high wear resistance properties with low value of coefficient of friction. These factors increase the useful life of the brake discs with minimal possibilities of brake fade. To study the effects of cryogenic treatment on the wear behaviour, two types of brake discs were cryotreated at 98K for 8 and 24 hours in a specially developed cryotreatment system using liquid nitrogen. Wear properties of the untreated and cryotreated test specimens were experimentally determined using the pin on disc type tribometer (ASTM G99-95). Similarly, the Rockwell hardness (HRC) of the specimens were tested in a hardness tester in accordance with ASTM E18. In this paper, the effects of cryotreatment on the wear and hardness properties of untreated and cryotreated brake discs are presented. Results indicate enhancement of wear properties and hardness after cryogenic treatment compared with the normal brakes discs.

Detection technology research on the one-way clutch of automatic brake adjuster

NASA Astrophysics Data System (ADS)

Jiang, Wensong; Luo, Zai; Lu, Yi

2013-10-01

In this article, we provide a new testing method to evaluate the acceptable quality of the one-way clutch of automatic brake adjuster. To analysis the suitable adjusting brake moment which keeps the automatic brake adjuster out of failure, we build a mechanical model of one-way clutch according to the structure and the working principle of one-way clutch. The ranges of adjusting brake moment both clockwise and anti-clockwise can be calculated through the mechanical model of one-way clutch. Its critical moment, as well, are picked up as the ideal values of adjusting brake moment to evaluate the acceptable quality of one-way clutch of automatic brake adjuster. we calculate the ideal values of critical moment depending on the different structure of one-way clutch based on its mechanical model before the adjusting brake moment test begin. In addition, an experimental apparatus, which the uncertainty of measurement is ±0.1Nm, is specially designed to test the adjusting brake moment both clockwise and anti-clockwise. Than we can judge the acceptable quality of one-way clutch of automatic brake adjuster by comparing the test results and the ideal values instead of the EXP. In fact, the evaluation standard of adjusting brake moment applied on the project are still using the EXP provided by manufacturer currently in China, but it would be unavailable when the material of one-way clutch changed. Five kinds of automatic brake adjusters are used in the verification experiment to verify the accuracy of the test method. The experimental results show that the experimental values of adjusting brake moment both clockwise and anti-clockwise are within the ranges of theoretical results. The testing method provided by this article vividly meet the requirements of manufacturer's standard.

49 CFR 229.53 - Brake gauges.

Code of Federal Regulations, 2010 CFR

2010-10-01

... TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Safety Requirements Brake System § 229.53 Brake gauges. All... engineer to aid in the control or braking of the train or locomotive shall be located so that they may be...

Fore-Aft Ground Force Adaptations to Induced Forelimb Lameness in Walking and Trotting Dogs

PubMed Central

Abdelhadi, Jalal; Wefstaedt, Patrick; Nolte, Ingo; Schilling, Nadja

2012-01-01

Animals alter their locomotor mechanics to adapt to a loss of limb function. To better understand their compensatory mechanisms, this study evaluated the changes in the fore-aft ground forces to forelimb lameness and tested the hypothesis that dogs unload the affected limb by producing a nose-up pitching moment via the exertion of a net-propulsive force when the lame limb is on the ground. Seven healthy Beagles walked and trotted at steady speed on an instrumented treadmill while horizontal force data were collected before and after a moderate lameness was induced. Peak, mean and summed braking and propulsive forces as well as the duration each force was exerted and the time to reach maximum force were evaluated for both the sound and the lame condition. Compared with the sound condition, a net-propulsive force was produced by the lame diagonal limbs due to a reduced braking force in the affected forelimb and an increased propulsive force in the contralateral hindlimb when the dogs walked and trotted. To regain pitch stability and ensure steady speed for a given locomotor cycle, the dogs produced a net-braking force when the sound diagonal limbs were on the ground by exerting greater braking forces in both limbs during walking and additionally reducing the propulsive force in the hindlimb during trotting. Consistent with the proposed mechanism, dogs maximize their double support phases when walking. Likely associated with the fore-aft force adaptations to lameness are changes in muscle recruitment that potentially result in short- and long-term effects on the limb and trunk muscles. PMID:23300614

Energy and wear optimisation of train longitudinal dynamics and of traction and braking systems

NASA Astrophysics Data System (ADS)

Conti, R.; Galardi, E.; Meli, E.; Nocciolini, D.; Pugi, L.; Rindi, A.

2015-05-01

Traction and braking systems deeply affect longitudinal train dynamics, especially when an extensive blending phase among different pneumatic, electric and magnetic devices is required. The energy and wear optimisation of longitudinal vehicle dynamics has a crucial economic impact and involves several engineering problems such as wear of braking friction components, energy efficiency, thermal load on components, level of safety under degraded or adhesion conditions (often constrained by the current regulation in force on signalling or other safety-related subsystem). In fact, the application of energy storage systems can lead to an efficiency improvement of at least 10% while, as regards the wear reduction, the improvement due to distributed traction systems and to optimised traction devices can be quantified in about 50%. In this work, an innovative integrated procedure is proposed by the authors to optimise longitudinal train dynamics and traction and braking manoeuvres in terms of both energy and wear. The new approach has been applied to existing test cases and validated with experimental data provided by Breda and, for some components and their homologation process, the results of experimental activities derive from cooperation performed with relevant industrial partners such as Trenitalia and Italcertifer. In particular, simulation results are referred to the simulation tests performed on a high-speed train (Ansaldo Breda Emu V250) and on a tram (Ansaldo Breda Sirio Tram). The proposed approach is based on a modular simulation platform in which the sub-models corresponding to different subsystems can be easily customised, depending on the considered application, on the availability of technical data and on the homologation process of different components.

Fallback level concepts for conventional and by-wire automotive brake systems

NASA Astrophysics Data System (ADS)

Retzer, H.; Mishra, R.; Ball, A.; Schmidt, K.

2012-05-01

Brake-by-wire represents the replacement of traditional brake components such as pumps, hoses, fluids, brake boosters, and master cylinders by electronic sensors and actuators. The different design of these brake concepts poses new challenges for the automotive industry with regard to availability and fallback levels in comparison to standard conventional brake systems. This contribution focuses on the development of appropriate fallback level concepts. Hardware-in-the-loop (HIL) techniques and field trials will be used to investigate the performance and the usability of such systems.

Laboratory testing of airborne brake wear particle emissions using a dynamometer system under urban city driving cycles

NASA Astrophysics Data System (ADS)

Hagino, Hiroyuki; Oyama, Motoaki; Sasaki, Sousuke

2016-04-01

To measure driving-distance-based mass emission factors for airborne brake wear particulate matter (PM; i.e., brake wear particles) related to the non-asbestos organic friction of brake assembly materials (pads and lining), and to characterize the components of brake wear particles, a brake wear dynamometer with a constant-volume sampling system was developed. Only a limited number of studies have investigated brake emissions under urban city driving cycles that correspond to the tailpipe emission test (i.e., JC08 or JE05 mode of Japanese tailpipe emission test cycles). The tests were performed using two passenger cars and one middle-class truck. The observed airborne brake wear particle emissions ranged from 0.04 to 1.4 mg/km/vehicle for PM10 (particles up to 10 μm (in size), and from 0.04 to 1.2 mg/km/vehicle for PM2.5. The proportion of brake wear debris emitted as airborne brake wear particles was 2-21% of the mass of wear. Oxygenated carbonaceous components were included in the airborne PM but not in the original friction material, which indicates that changes in carbon composition occurred during the abrasion process. Furthermore, this study identified the key tracers of brake wear particles (e.g., Fe, Cu, Ba, and Sb) at emission levels comparable to traffic-related atmospheric environments.

Experimental investigation of an accelerometer controlled automatic braking system

NASA Technical Reports Server (NTRS)

Dreher, R. C.; Sleeper, R. K.; Nayadley, J. R., Sr.

1972-01-01

An investigation was made to determine the feasibility of an automatic braking system for arresting the motion of an airplane by sensing and controlling braked wheel decelerations. The system was tested on a rotating drum dynamometer by using an automotive tire, wheel, and disk-brake assembly under conditions which included two tire loadings, wet and dry surfaces, and a range of ground speeds up to 70 knots. The controlling parameters were the rates at which brake pressure was applied and released and the Command Deceleration Level which governed the wheel deceleration by controlling the brake operation. Limited tests were also made with the automatic braking system installed on a ground vehicle in an effort to provide a more realistic proof of its feasibility. The results of this investigation indicate that a braking system which utilizes wheel decelerations as the control variable to restrict tire slip is feasible and capable of adapting to rapidly changing surface conditions.

Combined emergency braking and turning of articulated heavy vehicles

NASA Astrophysics Data System (ADS)

Morrison, Graeme; Cebon, David

2017-05-01

'Slip control' braking has been shown to reduce the emergency stopping distance of an experimental heavy goods vehicle by up to 19%, compared to conventional electronic/anti-lock braking systems (EBS). However, little regard has been given to the impact of slip control braking on the vehicle's directional dynamics. This paper uses validated computer models to show that slip control could severely degrade directional performance during emergency braking. A modified slip control strategy, 'attenuated slip demand' (ASD) control, is proposed in order to rectify this. Results from simulations of vehicle performance are presented for combined braking and cornering manoeuvres with EBS and slip control braking with and without ASD control. The ASD controller enables slip control braking to provide directional performance comparable with conventional EBS while maintaining a substantial stopping distance advantage. The controller is easily tuned to work across a wide range of different operating conditions.

Bio-kinetic energy harvesting using electroactive polymers

NASA Astrophysics Data System (ADS)

Slade, Jeremiah R.; Bowman, Jeremy; Kornbluh, Roy

2012-06-01

In hybrid vehicles, electric motors are used on each wheel to not only propel the car but also to decelerate the car by acting as generators. In the case of the human body, muscles spend about half of their time acting as a brake, absorbing energy, or doing what is known as negative work. Using dielectric elastomers it is possible to use the "braking" phases of walking to generate power without restricting or fatiguing the Warfighter. Infoscitex and SRI have developed and demonstrated methods for using electroactive polymers (EAPs) to tap into the negative work generated at the knee during the deceleration phase of the human gait cycle and convert it into electrical power that can be used to support wearable information systems, including display and communication technologies. The specific class of EAP that has been selected for these applications is termed dielectric elastomers. Because dielectric elastomers dissipate very little mechanical energy into heat, greater amounts of energy can be converted into electricity than by any other method. The long term vision of this concept is to have EAP energy harvesting cells located in components of the Warfighter ensemble, such as the boot uppers, knee pads and eventually even the clothing itself. By properly locating EAPs at these sites it will be possible to not only harvest power from the negative work phase but to actually reduce the amount of work done by the Warfighter's muscles during this phase, thereby reducing fatigue and minimizing the forces transmitted to the joints.

40 CFR 86.1912 - How do I determine whether an engine meets the vehicle-pass criteria?

Code of Federal Regulations, 2012 CFR

2012-07-01

..., depending on the pollutant, as follows: (i) NMHC: 0.17 grams per brake horsepower-hour. (ii) CO: 0.60 grams per brake horsepower-hour. (iii) NOX: 0.50 grams per brake horsepower-hour. (iv) PM: 0.10 grams per brake horsepower-hour. (v) NOX + NMHC: 0.67 grams per brake horsepower-hour. (4) Accuracy margins for...

40 CFR 86.1912 - How do I determine whether an engine meets the vehicle-pass criteria?

Code of Federal Regulations, 2013 CFR

2013-07-01

..., depending on the pollutant, as follows: (i) NMHC: 0.17 grams per brake horsepower-hour. (ii) CO: 0.60 grams per brake horsepower-hour. (iii) NOX: 0.50 grams per brake horsepower-hour. (iv) PM: 0.10 grams per brake horsepower-hour. (v) NOX + NMHC: 0.67 grams per brake horsepower-hour. (4) Accuracy margins for...

40 CFR 86.1912 - How do I determine whether an engine meets the vehicle-pass criteria?

Code of Federal Regulations, 2014 CFR

2014-07-01

..., depending on the pollutant, as follows: (i) NMHC: 0.17 grams per brake horsepower-hour. (ii) CO: 0.60 grams per brake horsepower-hour. (iii) NOX: 0.50 grams per brake horsepower-hour. (iv) PM: 0.10 grams per brake horsepower-hour. (v) NOX + NMHC: 0.67 grams per brake horsepower-hour. (4) Accuracy margins for...

Dynamics of Braking Vehicles: From Coulomb Friction to Anti-Lock Braking Systems

ERIC Educational Resources Information Center

Tavares, J. M.

2009-01-01

The dynamics of braking of wheeled vehicles is studied using the Coulomb approximation for the friction between road and wheels. The dependence of the stopping distance on the mass of the vehicle, on the number of its wheels and on the intensity of the braking torque is established. It is shown that there are two regimes of braking, with and…

Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy

NASA Astrophysics Data System (ADS)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-01-01

The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A "fiber muzzle brake" was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-outer-diameter, 360-μm-inner-diameter tube with a 275-μm-diameter through hole located 250 μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40±4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25±4 s (n=10) without visible distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers, respectively. The muzzle brake fiber tip simultaneously provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Dynamic analysis of elastic rubber tired car wheel breaking under variable normal load

NASA Astrophysics Data System (ADS)

Fedotov, A. I.; Zedgenizov, V. G.; Ovchinnikova, N. I.

2017-10-01

The purpose of the paper is to analyze the dynamics of the braking of the wheel under normal load variations. The paper uses a mathematical simulation method according to which the calculation model of an object as a mechanical system is associated with a dynamically equivalent schematic structure of the automatic control. Transfer function tool analyzing structural and technical characteristics of an object as well as force disturbances were used. It was proved that the analysis of dynamic characteristics of the wheel subjected to external force disturbances has to take into account amplitude and phase-frequency characteristics. Normal load variations impact car wheel braking subjected to disturbances. The closer slip to the critical point is, the higher the impact is. In the super-critical area, load variations cause fast wheel blocking.

Indonesian commercial bus drum brake system temperature model

NASA Astrophysics Data System (ADS)

Wibowo, D. B.; Haryanto, I.; Laksono, N. P.

2016-03-01

Brake system is the most significant aspect of an automobile safety. It must be able to slow the vehicle, quickly intervening and reliable under varying conditions. Commercial bus in Indonesia, which often stops suddenly and has a high initial velocity, will raise the temperature of braking significantly. From the thermal analysis it is observed that for the bus with the vehicle laden mass of 15 tons and initial velocity of 80 km/h the temperature is increasing with time and reaches the highest temperature of 270.1 °C when stops on a flat road and reaches 311.2 °C on a declination road angle, ø, 20°. These temperatures exceeded evaporation temperature of brake oil DOT 3 and DOT 4. Besides that, the magnitude of the braking temperature also potentially lowers the friction coefficient of more than 30%. The brakes are pressed repeatedly and high-g decelerations also causes brake lining wear out quickly and must be replaced every 1 month as well as the emergence of a large thermal stress which can lead to thermal cracking or thermal fatigue crack. Brake fade phenomenon that could be the cause of many buses accident in Indonesia because of the failure of the braking function. The chances of accidents will be even greater when the brake is worn and not immediately replaced which could cause hot spots as rivets attached to the brake drum and brake oil is not changed for more than 2 years that could potentially lower the evaporation temperature because of the effect hygroscopic.

Indonesian commercial bus drum brake system temperature model

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

Wibowo, D. B., E-mail: rmt.bowo@gmail.com; Haryanto, I., E-mail: ismoyo2001@yahoo.de; Laksono, N. P., E-mail: priyolaksono89@gmail.com

Brake system is the most significant aspect of an automobile safety. It must be able to slow the vehicle, quickly intervening and reliable under varying conditions. Commercial bus in Indonesia, which often stops suddenly and has a high initial velocity, will raise the temperature of braking significantly. From the thermal analysis it is observed that for the bus with the vehicle laden mass of 15 tons and initial velocity of 80 km/h the temperature is increasing with time and reaches the highest temperature of 270.1 °C when stops on a flat road and reaches 311.2 °C on a declination road angle,more » ø, 20°. These temperatures exceeded evaporation temperature of brake oil DOT 3 and DOT 4. Besides that, the magnitude of the braking temperature also potentially lowers the friction coefficient of more than 30%. The brakes are pressed repeatedly and high-g decelerations also causes brake lining wear out quickly and must be replaced every 1 month as well as the emergence of a large thermal stress which can lead to thermal cracking or thermal fatigue crack. Brake fade phenomenon that could be the cause of many buses accident in Indonesia because of the failure of the braking function. The chances of accidents will be even greater when the brake is worn and not immediately replaced which could cause hot spots as rivets attached to the brake drum and brake oil is not changed for more than 2 years that could potentially lower the evaporation temperature because of the effect hygroscopic.« less

Optical classification for quality and defect analysis of train brakes

NASA Astrophysics Data System (ADS)

Glock, Stefan; Hausmann, Stefan; Gerke, Sebastian; Warok, Alexander; Spiess, Peter; Witte, Stefan; Lohweg, Volker

2009-06-01

In this paper we present an optical measurement system approach for quality analysis of brakes which are used in high-speed trains. The brakes consist of the so called brake discs and pads. In a deceleration process the discs will be heated up to 500°C. The quality measure is based on the fact that the heated brake discs should not generate hot spots inside the brake material. Instead, the brake disc should be heated homogeneously by the deceleration. Therefore, it makes sense to analyze the number of hot spots and their relative gradients to create a quality measure for train brakes. In this contribution we present a new approach for a quality measurement system which is based on an image analysis and classification of infra-red based heat images. Brake images which are represented in pseudo-color are first transformed in a linear grayscale space by a hue-saturation-intensity (HSI) space. This transform is necessary for the following gradient analysis which is based on gray scale gradient filters. Furthermore, different features based on Haralick's measures are generated from the gray scale and gradient images. A following Fuzzy-Pattern-Classifier is used for the classification of good and bad brakes. It has to be pointed out that the classifier returns a score value for each brake which is between 0 and 100% good quality. This fact guarantees that not only good and bad bakes can be distinguished, but also their quality can be labeled. The results show that all critical thermal patterns of train brakes can be sensed and verified.

Study on Abrasive Wear of Brake Pad in the Large-megawatt Wind Turbine Brake Based on Deform Software

NASA Astrophysics Data System (ADS)

Zhang, Shengfang; Hao, Qiang; Sha, Zhihua; Yin, Jian; Ma, Fujian; Liu, Yu

2017-12-01

For the friction and wear issues of brake pads in the large-megawatt wind turbine brake during braking, this paper established the micro finite element model of abrasive wear by using Deform-2D software. Based on abrasive wear theory and considered the variation of the velocity and load in the micro friction and wear process, the Archard wear calculation model is developed. The influence rules of relative sliding velocity and friction coefficient in the brake pad and disc is analysed. The simulation results showed that as the relative sliding velocity increases, the wear will be more serious, while the larger friction coefficient lowered the contact pressure which released the wear of the brake pad.

Brake wear warning device: A concept

NASA Technical Reports Server (NTRS)

Hawkins, S. F.

1973-01-01

Heat-insulated wire is introduced through brake shoe and partially into brake lining. Wire is connected to positive terminal and light bulb. When brakes wear to critical point, contact between wire and wheel drum grounds circuit and turns on warning light.

Heavy and overweight vehicle brake testing : combination six-axle, final report.

DOT National Transportation Integrated Search

2017-05-01

The Heavy and Overweight Vehicle Brake Testing (HOVBT) program exists in order to provide information about the effect of gross vehicle weight (GVW) and on braking performance testing included service brake stopping distance tests, constant-pressure ...

Driving style recognition method using braking characteristics based on hidden Markov model

PubMed Central

Wu, Chaozhong; Lyu, Nengchao; Huang, Zhen

2017-01-01

Since the advantage of hidden Markov model in dealing with time series data and for the sake of identifying driving style, three driving style (aggressive, moderate and mild) are modeled reasonably through hidden Markov model based on driver braking characteristics to achieve efficient driving style. Firstly, braking impulse and the maximum braking unit area of vacuum booster within a certain time are collected from braking operation, and then general braking and emergency braking characteristics are extracted to code the braking characteristics. Secondly, the braking behavior observation sequence is used to describe the initial parameters of hidden Markov model, and the generation of the hidden Markov model for differentiating and an observation sequence which is trained and judged by the driving style is introduced. Thirdly, the maximum likelihood logarithm could be implied from the observable parameters. The recognition accuracy of algorithm is verified through experiments and two common pattern recognition algorithms. The results showed that the driving style discrimination based on hidden Markov model algorithm could realize effective discriminant of driving style. PMID:28837580

The antilock braking system anomaly: a drinking driver problem?

PubMed

Harless, David W; Hoffer, George E

2002-05-01

Antilock braking systems (ABS) have held promise for reducing the incidence of accidents because they reduce stopping times on slippery surfaces and allow drivers to maintain steering control during emergency braking. Farmer et al. (Accident Anal. Prevent. 29 (1997) 745) provide evidence that antilock brakes are beneficial to nonoccupants: a set of 1992 model General Motors vehicles equipped with antilock brakes were involved in significantly fewer fatal crashes in which occupants of other vehicles, pedestrians, or bicyclists were killed. But, perversely, the risk of death for occupants of vehicles equipped with antilock brakes increased significantly after adoption. Farmer (Accident Anal. Prevent. 33 (2001) 361) updates the analysis for 1996- 1998 and finds a significant attenuation in the ABS anomaly. Researchers have put forward two hypotheses to explain this antilock brake anomaly: risk compensation and improper operation of antilock brake-equipped vehicles. We provide strong evidence for the improper operation hypothesis by showing that the antilock brake anomaly is confined largely to drinking drivers. Further, we show that the attenuation phenomenon occurs consistently after the first three to four years of vehicle service.

An air brake model for longitudinal train dynamics studies

NASA Astrophysics Data System (ADS)

Wei, Wei; Hu, Yang; Wu, Qing; Zhao, Xubao; Zhang, Jun; Zhang, Yuan

2017-04-01

Experience of heavy haul train operation shows that heavy haul train fatigue fracture of coupler and its related components, even the accidents are caused by excessive coupler force. The most economical and effective method to study on train longitudinal impulse by reducing the coupler force is simulation method. The characteristics of train air brake system is an important excitation source for the study of longitudinal impulse. It is very difficult to obtain the braking characteristic by the test method, a better way to get the input parameters of the excitation source in the train longitudinal dynamics is modelling the train air brake system. In this paper, the air brake system model of integrated system of air brake and longitudinal dynamics is introduced. This introduce is focus on the locomotive automatic brake valve and vehicle distribution valve model, and the comparative analysis of the simulation and test results of the braking system is given. It is proved that the model can predict the characteristics of train braking system. This method provides a good solution for the excitation source of longitudinal dynamic analysis system.

NAC Aftermarket Brake Components Project (Secondary Items)

DTIC Science & Technology

2007-02-06

2. Appendix B. Test Plans and Sample Assignments for Disc Brake Pads and (Foundation) Drum Brake Shoes. 3. Appendix C. Test Plans and Sample...Assignments for Disc Brake Rotors and Drum Brake Drums . 4. Appendix D. Off-vehicle Inertia Dynamometer Test Procedures. 5. Appendix E. “Crack & Fatigue...apples” comparison testing processes, and require project outputs documents to be proofed by actual independent testing; HMMWV-ECV ( disc ) and HEMTT

Qualitative Maintenance Experience Handbook. P-3C/S-3A Supplement.

DTIC Science & Technology

1977-06-15

axle which automatically assists in disc alignment, a positive feature, in easing maintenance and preventing casual damage. Brake assemblies should...Reverse Of Removal Use brake tool to align brake discs . After Installation Actions: _ Bleed _ Rig _ Adjust X Service Lubricate - Boresight. _ Other...Hydraulic I Access Required: Test Equipment Required: Actions: 1. Check clearance of discs after brakes are put on. 2. Apply brakes . 8 ANALYST’S COMMENTS

Anti-lock brake system: an assessment of training on driver effectiveness.

PubMed

Mollenhauer, M A; Dingus, T A; Carney, C; Hankey, J M; Jahns, S

1997-01-01

When activated correctly, Anti-Lock Brake Systems (ABS) can provide drivers with the ability to stop a vehicle in shorter distances and allow for more vehicle control under heavy braking than conventional brake systems. This is especially true under wet or icy road conditions. However, it is believed that many drivers are either unaware of the correct method of activation or they revert back to the old method of pumping the brakes when they are faced with a hard braking situation. This paper examines the effectiveness of implementing low-cost training methods for alerting drivers to the correct brake activation technique. A 4-page, color training pamphlet was developed and subjects were given a short period of time to read it over before being asked to drive on an icy test track. Results indicated that those subjects who received the training were able to stop in shorter distances in a straight line braking event and more often used the correct brake activation technique than those subjects who did not receive the training. However, the stopping distance benefits were not realized in the curved and surprise braking events. These results suggest that the transfer of verbal knowledge may have value as a means for solving the apparent problem of improper ABS usage. However, some additional research should be done to validate these results. Since this experiment was conducted directly after the material was read, the possibility exists that without reinforcement, the trained braking techniques might become extinct in a short period of time.

Gravity brake

DOEpatents

Lujan, Richard E.

2001-01-01

A mechanical gravity brake that prevents hoisted loads within a shaft from free-falling when a loss of hoisting force occurs. A loss of hoist lifting force may occur in a number of situations, for example if a hoist cable were to break, the brakes were to fail on a winch, or the hoist mechanism itself were to fail. Under normal hoisting conditions, the gravity brake of the invention is subject to an upward lifting force from the hoist and a downward pulling force from a suspended load. If the lifting force should suddenly cease, the loss of differential forces on the gravity brake in free-fall is translated to extend a set of brakes against the walls of the shaft to stop the free fall descent of the gravity brake and attached load.

Transportability

DTIC Science & Technology

2013-04-25

wheel (distance, brake stopping) ± 0.1 m (± 0.3 ft) Walking wheel (distance, road) ± 0.1 km (± 0.06 mile) Speedometer (speed) ± 0.1 km/hr...to impact or at the point of impact if feasible. c. Position the stationary railcar(s) with its coupler compressed and its air and hand brakes ...the prevailing wind. Engage the parking brakes on vehicles, trailers or weapon systems equipped with parking brake systems. Secure loose brake lines

77 FR 45981 - Airworthiness Directives; Bombardier, Inc. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-02

... the affected parking brake hydraulic accumulator, and relocating the parking brake accumulator, on the... parking brake hydraulic accumulator, which could result in damage to the airplane's primary structures... (P/N) 08-60197-001 (Parking Brake Accumulator), are installed on the aeroplanes listed in the...

Roller Locking Brake

NASA Technical Reports Server (NTRS)

Vranish, John M.

1993-01-01

Roller locking brake is normally braking rotary mechanism allowing free rotation when electromagnet in mechanism energized. Well suited to robots and other machinery which automatic braking upon removal of electrical power required. More compact and reliable. Requires little electrical power to maintain free rotation and exhibits minimal buildup of heat.

Vehicle Hybrid Braking Control Using Sliding Mode Control

NASA Astrophysics Data System (ADS)

Kasahara, Misawa; Kanai, Yuki; Shiraki, Ryoko; Mori, Yasuchika

Anti-lock brake system and brake-by-wire are proposed in the vehicle control using a brake, and the braking power is expected to be improved more than ever. The researches such as an application to the ABS of Siliding mode control which considered a actuator dynamics and a hybrid control of the brake using model reference adaptive control are done so far. However, in the former case, speed following that becomes a target exists physically impossible situation by saturation of tire frictional force because only speed following is done. In the latter, the model error is caused because the simulation model and the controller design model are different. Therefore, there is a problem that an accurate follow cannot be done. In this paper, the braking control is performed using the sliding mode control which has high robustness for disturbance that fulfils matching conditions. In so doing, it aims at the achievement of optimal braking control to switch wheel speed following to slip ratio following.

Evaluation the course of the vehicle braking process in case of hydraulic circuit malfunction

NASA Astrophysics Data System (ADS)

Szczypiński-Sala, W.; Lubas, J.

2016-09-01

In the paper, the results of the research were discussed, the aim of which was the evaluation of the vehicle braking performance efficiency and the course of this process with regard to the dysfunction which may occur in braking hydraulic circuit. As part of the research, on-road tests were conducted. During the research, the delay of the vehicle when braking was measured with the use of the set of sensors placed in the parallel and the perpendicular axis of the vehicle. All the tests were conducted on the same flat section of asphalt road with wet surface. Conditions of diminished tire-to-road adhesion were chosen in order to force the activity of anti-lock braking system. The research was conducted comparatively for the vehicle with acting anti-lock braking system and subsequently for the vehicle without the system. In both cases, there was a subsequent evaluation of the course of braking with efficient braking system and with the dysfunction of hydraulic circuit.

Performance of an aircraft tire under cyclic braking and of a currently operational antiskid braking system

NASA Technical Reports Server (NTRS)

Tanner, J. A.

1972-01-01

An experimental investigation was conducted to study the performance of an aircraft tire under cyclic braking conditions and to study the performance of a currently operational aircraft antiskid braking system. Dry, damp, and flooded runway surface conditions were used in the investigation. The results indicated that under cyclic braking conditions the braking and cornering-force friction coefficients may be influenced by fluctuations in the vertical load, flexibility in the wheel support, and the spring coupling between the wheel and the tire-pavement interface. The cornering capability was shown to be negligible at wheel slip ratios well below a locked-wheel skid under all test surface conditions. The maximum available brake-force friction coefficient was shown to be dependent upon the runway surface condition, upon velocity, and, for wet runways, upon tire differences. Moderate reductions in vertical load and brake system pressure did not significantly affect the overall wet-runway performance of the tire.

Lipids, CHOs, proteins: can all macronutrients put a 'brake' on eating?

PubMed

Shin, H S; Ingram, J R; McGill, A-T; Poppitt, S D

2013-08-15

The gastrointestinal (GI) tract and specifically the most distal part of the small intestine, the ileum, has become a renewed focus of interest for mechanisms targeting appetite suppression. The 'ileal brake' is stimulated when energy-containing nutrients are delivered beyond the duodenum and jejunum and into the ileum, and is named for the feedback loop which slows or 'brakes' gastric emptying and duodeno-jejunal motility. More recently it has been hypothesized that the ileal brake also promotes secretion of satiety-enhancing GI peptides and suppresses hunger, placing a 'brake' on food intake. Postprandial delivery of macronutrients to the ileum, other than unavailable carbohydrates (CHO) which bypass absorption in the small intestine en route to fermentation in the large bowel, is an uncommon event and hence this brake mechanism is rarely activated following a meal. However the ability to place a 'brake' on food intake through delivery of protected nutrients to the ileum is both intriguing and challenging. This review summarizes the current clinical and experimental evidence for activation of the ileal brake by the three food macronutrients, with emphasis on eating behavior and satiety as well as GI function. While clinical studies have shown that exposure of the ileum to lipids, CHOs and proteins may activate GI components of the ileal brake, such as decreased gut motility, gastric emptying and secretion of GI peptides, there is less evidence as yet to support a causal relationship between activation of the GI brake by these macronutrients and the suppression of food intake. The predominance of evidence for an ileal brake on eating comes from lipid studies, where direct lipid infusion into the ileum suppresses both hunger and food intake. Outcomes from oral feeding studies are less conclusive with no evidence that 'protected' lipids have been successfully delivered into the ileum in order to trigger the brake. Whether CHO or protein may induce the ileal brake and suppress food intake has to date been little investigated, although both clearly have GI mediated effects. This review provides an overview of the mechanisms and mediators of activation of the ileal brake and assesses whether it may play an important role in appetite suppression. © 2013.

KSC-04PD-1030

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. -- In the Orbiter Processing Facility, workers remove the Rudder Speed Brake panel on the vertical tail of the orbiter Atlantis. The Rudder Speed Brake is being removed for inspection and maintenance prior to Return to Flight. The vertical tail consists of a structural fin surface made of aluminum, the Rudder Speed Brake surface, a tip and a lower trailing edge. The rudder splits into two halves to serve as a speed brake. The vertical tail and Rudder Speed Brake are covered with a reusable thermal protection system. The Rudder Speed Brake is used to guide and slow the Shuttle as it comes in for a landing.

Failure analysis of energy storage spring in automobile composite brake chamber

NASA Astrophysics Data System (ADS)

Luo, Zai; Wei, Qing; Hu, Xiaofeng

2015-02-01

This paper set energy storage spring of parking brake cavity, part of automobile composite brake chamber, as the research object. And constructed the fault tree model of energy storage spring which caused parking brake failure based on the fault tree analysis method. Next, the parking brake failure model of energy storage spring was established by analyzing the working principle of composite brake chamber. Finally, the data of working load and the push rod stroke measured by comprehensive test-bed valve was used to validate the failure model above. The experimental result shows that the failure model can distinguish whether the energy storage spring is faulted.

IR-camera methods for automotive brake system studies

NASA Astrophysics Data System (ADS)

Dinwiddie, Ralph B.; Lee, Kwangjin

1998-03-01

Automotive brake systems are energy conversion devices that convert kinetic energy into heat energy. Several mechanisms, mostly related to noise and vibration problems, can occur during brake operation and are often related to non-uniform temperature distribution on the brake disk. These problems are of significant cost to the industry and are a quality concern to automotive companies and brake system vendors. One such problem is thermo-elastic instabilities in brake system. During the occurrence of these instabilities several localized hot spots will form around the circumferential direction of the brake disk. The temperature distribution and the time dependence of these hot spots, a critical factor in analyzing this problem and in developing a fundamental understanding of this phenomenon, were recorded. Other modes of non-uniform temperature distributions which include hot banding and extreme localized heating were also observed. All of these modes of non-uniform temperature distributions were observed on automotive brake systems using a high speed IR camera operating in snap-shot mode. The camera was synchronized with the rotation of the brake disk so that the time evolution of hot regions could be studied. This paper discusses the experimental approach in detail.

Feedback brake distribution control for minimum pitch

NASA Astrophysics Data System (ADS)

Tavernini, Davide; Velenis, Efstathios; Longo, Stefano

2017-06-01

The distribution of brake forces between front and rear axles of a vehicle is typically specified such that the same level of brake force coefficient is imposed at both front and rear wheels. This condition is known as 'ideal' distribution and it is required to deliver the maximum vehicle deceleration and minimum braking distance. For subcritical braking conditions, the deceleration demand may be delivered by different distributions between front and rear braking forces. In this research we show how to obtain the optimal distribution which minimises the pitch angle of a vehicle and hence enhances driver subjective feel during braking. A vehicle model including suspension geometry features is adopted. The problem of the minimum pitch brake distribution for a varying deceleration level demand is solved by means of a model predictive control (MPC) technique. To address the problem of the undesirable pitch rebound caused by a full-stop of the vehicle, a second controller is designed and implemented independently from the braking distribution in use. An extended Kalman filter is designed for state estimation and implemented in a high fidelity environment together with the MPC strategy. The proposed solution is compared with the reference 'ideal' distribution as well as another previous feed-forward solution.

Investigation on the gaseous and particulate emissions of a compression ignition engine fueled with diesel-dimethyl carbonate blends.

PubMed

Cheung, C S; Zhu, Ruijun; Huang, Zuohua

2011-01-01

The effect of dimethyl carbonate (DMC) on the gaseous and particulate emissions of a diesel engine was investigated using Euro V diesel fuel blended with different proportions of DMC. Combustion analysis shows that, with the blended fuel, the ignition delay and the heat release rate in the premixed combustion phase increase, while the total combustion duration and the fuel consumed in the diffusion combustion phase decrease. Compared with diesel fuel, with an increase of DMC in the blended fuel, the brake thermal efficiency is slightly improved but the brake specific fuel consumption increases. On the emission side, CO increases significantly at low engine load but decreases at high engine load while HC decreases slightly. NO(x) reduces slightly but the reduction is not statistically significant, while NO(2) increases slightly. Particulate mass and number concentrations decrease upon using the blended fuel while the geometric mean diameter of the particles shifts towards smaller size. Overall speaking, diesel-DMC blends lead to significant improvement in particulate emissions while the impact on CO, HC and NO(x) emissions is small. Copyright © 2010 Elsevier B.V. All rights reserved.

Elemental composition of current automotive braking materials and derived air emission factors

NASA Astrophysics Data System (ADS)

Hulskotte, J. H. J.; Roskam, G. D.; Denier van der Gon, H. A. C.

2014-12-01

Wear-related PM emissions are an important constituent of total PM emissions from road transport. Due to ongoing (further) exhaust emission reduction wear emissions may become the dominant PM source from road transport in the near future. The chemical composition of the wear emissions is crucial information to assess the potential health relevance of these PM emissions. Here we provide an elemental composition profile of brake wear emissions as used in the Netherlands in 2012. In total, 65 spent brake pads and 15 brake discs were collected in car maintenance shops from in-use personal cars vehicles and analyzed with XRF for their metal composition (Fe, Cu, Zn, Sn, Al, Si, Zr, Ti, Sb, Cr, Mo, Mn, V, Ni, Bi, W, P, Pb and Co). Since car, engine and safety regulations are not nationally determined but controlled by European legislation the resulting profiles will be representative for the European personal car fleet. The brake pads contained Fe and Cu as the dominant metals but their ratio varied considerably, other relatively important metals were Sn, Zn and Sb. Overall a rather robust picture emerged with Fe, Cu, Zn and Sn together making up about 80-90% of the metals present in brake pads. Because the XRF did not give information on the contents of other material such as carbon, oxygen and sulphur, a representative selection of 9 brake pads was further analyzed by ICP-MS and a carbon and sulphur analyzer. The brake pads contained about 50% of non-metal material (26% C, 3% S and the remainder mostly oxygen and some magnesium). Based on our measurements, the average brake pad profile contained 20% Fe, 10% Cu, 4% Zn and 3% Sn as the dominant metals. The brake discs consisted almost entirely of metal with iron being the dominant metal (>95%) and only traces of other metals (<1% for individual metals). Non-metal components in the discs were 2-3% Silicon and, according to literature, ∼3% carbon. The robust ratio between Fe and Cu as found on kerbsides has been used to estimate the contribution of brake pads and brake discs to total brake wear. Based on this approach our hypothesis is that 70% of the brake wear originates from the discs and only 30% from the brake pads.

29 CFR 1926.601 - Motor vehicles.

Code of Federal Regulations, 2010 CFR

2010-07-01

... that operate within an off-highway jobsite, not open to public traffic. The requirements of this.... (1) All vehicles shall have a service brake system, an emergency brake system, and a parking brake... vehicles, or combination of vehicles, shall have brake lights in operable condition regardless of light...

NHTSA's heavy duty vehicle brake research program report number 11 : evaluation of stopping performance of trailer antilock brake systems

DOT National Transportation Integrated Search

1997-04-01

In order to better understand the functioning of antilock brake systems on pneumatically braked trailers, a series of tests were conducted to evaluate different ABS control strategies, performance variations among systems supplied by different manufa...

49 CFR 229.57 - Foundation brake gear.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Foundation brake gear. 229.57 Section 229.57 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Foundation brake gear. A lever, rod, brake beam, hanger, or pin may not be worn through more than 30 percent...

49 CFR 229.135 - Event recorders.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Locomotive position in consist (lead or trail); (xxiii) Tractive effort; (xxiv) Cruise control on/off, if so...; (xviii) Brakes apply summary train line; (xix) Brakes released summary train line; (xx) Cruise control on... determining, that a brake application or release resulted from manipulation of brake controls at the position...

49 CFR 229.135 - Event recorders.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Locomotive position in consist (lead or trail); (xxiii) Tractive effort; (xxiv) Cruise control on/off, if so...; (xviii) Brakes apply summary train line; (xix) Brakes released summary train line; (xx) Cruise control on... determining, that a brake application or release resulted from manipulation of brake controls at the position...

49 CFR 229.135 - Event recorders.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Locomotive position in consist (lead or trail); (xxiii) Tractive effort; (xxiv) Cruise control on/off, if so...; (xviii) Brakes apply summary train line; (xix) Brakes released summary train line; (xx) Cruise control on... determining, that a brake application or release resulted from manipulation of brake controls at the position...

49 CFR 229.135 - Event recorders.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Locomotive position in consist (lead or trail); (xxiii) Tractive effort; (xxiv) Cruise control on/off, if so...; (xviii) Brakes apply summary train line; (xix) Brakes released summary train line; (xx) Cruise control on... determining, that a brake application or release resulted from manipulation of brake controls at the position...

49 CFR 393.5 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... processing plant or storage location, as evidenced by skeletal construction that accommodates harvest... mechanism used to stop, or hold a vehicle stationary. Brake power assist unit. A device installed in a... force on the service brake control. Brake power unit. A device installed in a brake system that provides...

49 CFR 393.5 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

... processing plant or storage location, as evidenced by skeletal construction that accommodates harvest... mechanism used to stop, or hold a vehicle stationary. Brake power assist unit. A device installed in a... force on the service brake control. Brake power unit. A device installed in a brake system that provides...

14 CFR 23.735 - Brakes.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Brakes. 23.735 Section 23.735 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS... § 23.735 Brakes. Link to an amendment published at 76 FR 75757, December 2, 2011. (a) Brakes must be...

49 CFR 383.95 - Restrictions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... the skills test and the restriction, air brakes shall include any braking system operating fully or...; REQUIREMENTS AND PENALTIES Vehicle Groups and Endorsements § 383.95 Restrictions. (a) Air brake restrictions... skills test in a vehicle not equipped with air brakes, the State must indicate on the CDL, if issued...

Chain-reaction crash on a highway in high visibility

NASA Astrophysics Data System (ADS)

Nagatani, Takashi

2016-05-01

We study the chain-reaction crash (multiple-vehicle collision) in high-visibility condition on a highway. In the traffic situation, drivers control their vehicles by both gear-changing and braking. Drivers change the gears according to the headway and brake according to taillights of the forward vehicle. We investigate whether or not the first collision induces the chain-reaction crash numerically. It is shown that dynamic transitions occur from no collisions, through a single collision, to multiple collisions with decreasing the headway. Also, we find that the dynamic transition occurs from the finite chain reaction to the infinite chain reaction when the headway is less than the critical value. We compare the multiple-vehicle collisions in high-visibility with that in low-visibility. We derive the transition points and the region maps for the chain-reaction crash in high visibility.

Effect of Pertalite-Spiritus Blend Fuel on Performance of Single Cylinder Spark Ignition Engine

NASA Astrophysics Data System (ADS)

Wibowo, H.; Susastriawan, A. A. P.; Andrian, D.

2018-02-01

This work aims to experimentally investigate an effect of Spiritus and Pertalite blend on engine’s performance (brake horsepower and torque, specific fuel consumption rate, and exhaust gas emission). The tests are conducted at 3000-7000 rpm for four different fuels, i.e., pertalite, 95%P-5%S, 90%P-10%S, and 85%P-15%S to obtain an optimum ratio of the Pertalite-Spiritus blend. The blend ratios of Pertalite (P) and Spiritus (S) are measured by volume. The result shows that addition of 15% Spiritus (by volume) on Pertalilte can enhance the combustion process of the blend hence increasing engine’s brake horsepower and decreasing specific fuel consumption rate. However, engine’s torque is lower when using the blend 85%P-15%S if compared with using Pertalite.

Aspects regarding manufacturing technologies of composite materials for brake pad application

NASA Astrophysics Data System (ADS)

Craciun, A. L.; Hepuţ, T.; Pinca-Bretotean, C.

2018-01-01

Current needs in road safety, requires the development of new technical solutions for automotive braking system. Their safe operation is subject to following factors: concept design, materials used and electronic control. Among the factors previously listed, choice of materials and manufacturing processes are difficult stage but very important for achieving technical performance and getting a relatively small cost of constituting parts of brake system. The choice is based on the promotion of organic composite material, popular in areas where the weight of materials plays an important role. The brake system is composed of many different parts including brake pads, a master cylinder, wheel cylinders and a hydraulic control system. The brake pads are an important component in the braking system of automotive. These are of different types, suitable for different types of automotive and engines. Brake pads are designed for friction stability, durability, minimization of noise and vibration. The typology of the brake pads depends on the material which they are made. The aim of this paper is to presents the manufacturing technologies for ten recipes of composite material used in brake pads applications. In this work will be done: choosing the constituents of the recipes, investigation of their basic characteristics, setting the proportions of components, obtaining the composite materials in laboratory, establishing the parameters of manufacturing technology and technological analysis.

Evaluation of a sudden brake warning system: effect on the response time of the following driver.

PubMed

Isler, Robert B; Starkey, Nicola J

2010-07-01

This study used a video-based braking simulation dual task to carry out a preliminary evaluation of the effect of a sudden brake warning system (SBWS) in a leading passenger vehicle on the response time of the following driver. The primary task required the participants (N=25, 16 females, full NZ license holders) to respond to sudden braking manoeuvres of a lead vehicle during day and night driving, wet and dry conditions and in rural and urban traffic, while concurrently performing a secondary tracking task using a computer mouse. The SBWS in the lead vehicle consisted of g-force controlled activation of the rear hazard lights (the rear indicators flashed), in addition to the standard brake lights. Overall, the results revealed that responses to the braking manoeuvres of the leading vehicles when the hazard lights were activated by the warning system were 0.34 s (19%) faster compared to the standard brake lights. The SBWS was particularly effective when the simulated braking scenario of the leading vehicle did not require an immediate and abrupt braking response. Given this, the SBWS may also be beneficial for allowing smoother deceleration, thus reducing fuel consumption. These preliminary findings justify a larger, more ecologically valid laboratory evaluation which may lead to a naturalistic study in order to test this new technology in 'real world' braking situations. Copyright 2009 Elsevier Ltd. All rights reserved.

Relationship Between Kinematic and Physiological Indices During Braking Events of Different Intensities.

PubMed

Musicant, Oren; Botzer, Assaf; Laufer, Ilan; Collet, Christian

2018-05-01

Objective To study the relationship between physiological indices and kinematic indices during braking events of different intensities. Background Based on mental workload theory, driving and other task demands may generate changes in physiological indices, such as the driver's heart rate and skin conductance. However, no attempts were made to associate changes in physiological indices with changes in vehicle kinematics that result from the driver attempts to meet task demands. Method Twenty-five drivers participated in a field experiment. We manipulated braking demands using roadside signs to communicate the speed (km/h) before braking (50 or 60) and the target speed for braking (30 or to a complete stop). In an additional session, we asked drivers to brake as if they were responding to an impending collision. We analyzed the relationship between the intensities of braking events as measured by deceleration values (g) and changes in heart rate, heart rate variability, and skin conductance. Results All physiological indices were associated with deceleration intensity. Especially salient were the differences in physiological indices between the intensive (|g| > 0.5) and nonintensive braking events. The strongest relationship was between braking intensity and skin conductance. Conclusions Skin conductance, heart rate, and heart rate variability can mirror the mental workload elicited by varying braking intensities. Application Associating vehicle kinematics with physiological indices related to short-term driving events may help improve the performance of driver assistance systems.

The Effect of a Variable Disc Pad Friction Coefficient for the Mechanical Brake System of a Railway Vehicle

PubMed Central

Lee, Nam-Jin; Kang, Chul-Goo

2015-01-01

A brake hardware-in-the-loop simulation (HILS) system for a railway vehicle is widely applied to estimate and validate braking performance in research studies and field tests. When we develop a simulation model for a full vehicle system, the characteristics of all components are generally properly simplified based on the understanding of each component’s purpose and interaction with other components. The friction coefficient between the brake disc and the pad used in simulations has been conventionally considered constant, and the effect of a variable friction coefficient is ignored with the assumption that the variability affects the performance of the vehicle braking very little. However, the friction coefficient of a disc pad changes significantly within a range due to environmental conditions, and thus, the friction coefficient can affect the performance of the brakes considerably, especially on the wheel slide. In this paper, we apply a variable friction coefficient and analyzed the effects of the variable friction coefficient on a mechanical brake system of a railway vehicle. We introduce a mathematical formula for the variable friction coefficient in which the variable friction is represented by two variables and five parameters. The proposed formula is applied to real-time simulations using a brake HILS system, and the effectiveness of the formula is verified experimentally by testing the mechanical braking performance of the brake HILS system. PMID:26267883

The Effect of a Variable Disc Pad Friction Coefficient for the Mechanical Brake System of a Railway Vehicle.

PubMed

Lee, Nam-Jin; Kang, Chul-Goo

2015-01-01

A brake hardware-in-the-loop simulation (HILS) system for a railway vehicle is widely applied to estimate and validate braking performance in research studies and field tests. When we develop a simulation model for a full vehicle system, the characteristics of all components are generally properly simplified based on the understanding of each component's purpose and interaction with other components. The friction coefficient between the brake disc and the pad used in simulations has been conventionally considered constant, and the effect of a variable friction coefficient is ignored with the assumption that the variability affects the performance of the vehicle braking very little. However, the friction coefficient of a disc pad changes significantly within a range due to environmental conditions, and thus, the friction coefficient can affect the performance of the brakes considerably, especially on the wheel slide. In this paper, we apply a variable friction coefficient and analyzed the effects of the variable friction coefficient on a mechanical brake system of a railway vehicle. We introduce a mathematical formula for the variable friction coefficient in which the variable friction is represented by two variables and five parameters. The proposed formula is applied to real-time simulations using a brake HILS system, and the effectiveness of the formula is verified experimentally by testing the mechanical braking performance of the brake HILS system.

Talking about the Automobile Braking System

NASA Astrophysics Data System (ADS)

Xu, Zhiqiang

2017-12-01

With the continuous progress of society, the continuous development of the times, people’s living standards continue to improve, people continue to improve the pursuit. With the rapid development of automobile manufacturing, the car will be all over the tens of thousands of households, the increase in car traffic, a direct result of the incidence of traffic accidents. Brake system is the guarantee of the safety of the car, its technical condition is good or bad, directly affect the operational safety and transportation efficiency, so the brake system is absolutely reliable. The requirements of the car on the braking system is to have a certain braking force to ensure reliable work in all cases, light and flexible operation. Normal braking should be good performance, in addition to a foot sensitive, the emergency brake four rounds can not be too long, not partial, not ring.

Research on squeal noise of tread brake system in rail freight vehicle

NASA Astrophysics Data System (ADS)

Zhang, Jun; Li, Yong-hua; Fang, Ji; Zhao, Wen-zhong

2017-07-01

Brake squeal is a result of a unstable flutter from brake system, it results to the noise pollution in railway side and excessive wear of wheel tread. A finite element model of brake system for rail freight vehicle is set up, the contact and friction between the brake shoe and wheel tread is considered, the complex modals of brake system are calculated, the possibility of happening chatter and squeal noise are analyzed. The results show that the pressure angle or the brake force direction have a important influence on the unstable chatter and squeal noise, the more greater the pressure angle deviates from the wheel center, the more greater the possibility of happening chatter and squeal noise is, and the possibility of happening chatter and squeal noise is also increased along with the addition of friction factor.

Performance and economic analysis of a plug and play regenerative brake for improving energy efficiency for traction elevators

NASA Astrophysics Data System (ADS)

Jeraputra, Chuttchaval; Tiptipakorn, Supun

2017-05-01

This paper presents performance and economic analysis of a plug and play regenerative brake for improving energy efficiency for traction elevators. The proposed regenerative brake recycles the energy loss of a dynamic brake and feeds into the grid while an elevator inverter is operating in the braking mode. According to field measurement of energy consumption, it reveals that the efficiency can be improved as much as 18%. The prototype of a regenerative brake 12 kW, 400V, 3ϕ is developed and tested on an elevator simulator. It is shown that it can transfer energy out of a DC capacitor before the dynamic brake kicks in. Further, an economic analysis is provided to carry out the payback period and the present worth equivalent to confirm economic feasibility.

Emergency braking is affected by the use of cruise control.

PubMed

Jammes, Yves; Behr, Michel; Llari, Maxime; Bonicel, Sarah; Weber, Jean Paul; Berdah, Stephane

2017-08-18

We compared the differences in the braking response to vehicle collision between an active human emergency braking (control condition) and cruise control (CC) or adaptive cruise control (ACC). In 11 male subjects, age 22 to 67 years, we measured the active emergency braking response during manual driving using the accelerator pedal (control condition) or in condition mimicking CC or ACC. In both conditions, we measured the brake reaction time (BRT), delay to produce the peak braking force (PBD), total emergency braking response (BRT + PBD), and peak braking force (PBF). Electromyograms of leg and thigh muscles were recorded during braking. The tonic vibratory response (TVR), Hoffman reflex (HR), and M-waves were recorded in leg muscles to explore the change in sensorimotor control. No difference in PBF, TVR amplitude, HR latency, and H max /M max ratio were found between the control and CC/ACC conditions. On the other hand, BRT and PBD were significantly lengthened in the CC/ACC condition (240 ± 13 ms and 704 ± 70 ms, respectively) compared to control (183 ± 7 ms and 568 ± 36 ms, respectively). BRT increased with the age of participants and the driving experience shortened PBD and increased PBF. In male subjects, driving in a CC/ACC condition significantly delays the active emergency braking response to vehicle collision. This could result from higher amplitude of leg motion in the CC/ACC condition and/or by the age-related changes in motor control. Car and truck drivers must take account of the significant increase in the braking distance in a CC/ACC condition.

Analysis of the stability of PTW riders in autonomous braking scenarios.

PubMed

Symeonidis, Ioannis; Kavadarli, Gueven; Erich, Schuller; Graw, Matthias; Peldschus, Steffen

2012-11-01

While fatalities of car occupants in the EU decreased remarkably over the last decade, Powered Two Wheelers (PTWs) fatalities still increase following the increase of PTW ownership. Autonomous braking systems have been implemented in several types of vehicles and are presently addressed by research in the field of PTWs. A major concern in this context is the rider stability. Experiments with volunteers were performed in order to find out whether autonomous braking for PTWs will produce a greater instability of the rider in comparison to manual braking. The PTW's braking conditions were simulated in a laboratory with a motorcycle mock-up mounted on a sled, which was accelerated with an average of 0.35 g. The motion of the rider was captured in autonomous braking scenarios with and without pre-warning as well as in manual braking scenarios. No significant differences between the scenarios were found with respect to maximum forward displacement of the volunteer's torso and head (p<0.05). By performing clustering analysis on two kinematic parameters, two different strategies of the volunteers were identified. They were not related to the braking scenarios. A relation of the clusters with the initial posture represented by the elbow angle was revealed (p<0.05). It is concluded that autonomous braking at low deceleration will not cause significant instabilities of the rider in comparison to manual braking in idealized laboratory conditions. Based on this, further research into the development and implementation of autonomous braking systems for PTWs, e.g. by extensive riding tests, seems valuable. Copyright © 2011 Elsevier Ltd. All rights reserved.

30 CFR 56.14101 - Brakes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... mobile equipment shall be equipped with a service brake system capable of stopping and holding the... which is not originally equipped with brakes unless the manner in which the equipment is being operated requires the use of brakes for safe operation. This standard does not apply to rail equipment. (2) If...

30 CFR 57.14101 - Brakes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... mobile equipment shall be equipped with a service brake system capable of stopping and holding the... which is not originally equipped with brakes unless the manner in which the equipment is being operated requires the use of brakes for safe operation. This standard does not apply to rail equipment. (2) If...

49 CFR 570.6 - Brake power unit.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 6 2010-10-01 2010-10-01 false Brake power unit. 570.6 Section 570.6... Pounds or Less § 570.6 Brake power unit. (a) Vacuum hoses shall not be collapsed, abraded, broken... brake pedal, the pedal shall fall slightly when the engine is started, demonstrating integrity of the...

49 CFR 232.109 - Dynamic brake requirements.

Code of Federal Regulations, 2011 CFR

2011-10-01

... TRAINS AND EQUIPMENT; END-OF-TRAIN DEVICES General Requirements § 232.109 Dynamic brake requirements. (a... operational status of the dynamic brakes on all locomotive units in the consist at the initial terminal for a..., all inoperative dynamic brakes shall be repaired within 30 calendar days of becoming inoperative or at...

49 CFR 232.109 - Dynamic brake requirements.

Code of Federal Regulations, 2010 CFR

2010-10-01

... system that includes dynamic brakes shall adopt and comply with written operating rules governing safe... verifiable data and research. (k) A railroad operating a train with a brake system that includes dynamic... 49 Transportation 4 2010-10-01 2010-10-01 false Dynamic brake requirements. 232.109 Section 232...

30 CFR 77.1401 - Automatic controls and brakes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic controls and brakes. 77.1401 Section... MINES Personnel Hoisting § 77.1401 Automatic controls and brakes. Hoists and elevators shall be equipped with overspeed, overwind, and automatic stop controls and with brakes capable of stopping the elevator...

30 CFR 75.1404 - Automatic brakes; speed reduction gear.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic brakes; speed reduction gear. 75.1404... Automatic brakes; speed reduction gear. [Statutory Provisions] Each locomotive and haulage car used in an... permit automatic brakes, locomotives and haulage cars shall be subject to speed reduction gear, or other...

30 CFR 75.1404 - Automatic brakes; speed reduction gear.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic brakes; speed reduction gear. 75.1404... Automatic brakes; speed reduction gear. [Statutory Provisions] Each locomotive and haulage car used in an... permit automatic brakes, locomotives and haulage cars shall be subject to speed reduction gear, or other...

16 CFR 1512.5 - Requirements for braking system.

Code of Federal Regulations, 2011 CFR

2011-01-01

... the braking force transmitted to the rear wheel shall be in accordance with the sidewalk bicycle.... Bicycles shall be equipped with front- and rear-wheel brakes or rear-wheel brakes only. (b) Handbrakes. Handbrakes shall be tested at least ten times by applying a force sufficient to cause the handlever to...

16 CFR 1512.5 - Requirements for braking system.

Code of Federal Regulations, 2012 CFR

2012-01-01

... the braking force transmitted to the rear wheel shall be in accordance with the sidewalk bicycle.... Bicycles shall be equipped with front- and rear-wheel brakes or rear-wheel brakes only. (b) Handbrakes. Handbrakes shall be tested at least ten times by applying a force sufficient to cause the handlever to...

16 CFR 1512.5 - Requirements for braking system.

Code of Federal Regulations, 2014 CFR

2014-01-01

... the braking force transmitted to the rear wheel shall be in accordance with the sidewalk bicycle.... Bicycles shall be equipped with front- and rear-wheel brakes or rear-wheel brakes only. (b) Handbrakes. Handbrakes shall be tested at least ten times by applying a force sufficient to cause the handlever to...

16 CFR 1512.5 - Requirements for braking system.

Code of Federal Regulations, 2010 CFR

2010-01-01

... the braking force transmitted to the rear wheel shall be in accordance with the sidewalk bicycle.... Bicycles shall be equipped with front- and rear-wheel brakes or rear-wheel brakes only. (b) Handbrakes. Handbrakes shall be tested at least ten times by applying a force sufficient to cause the handlever to...

30 CFR 75.523-3 - Automatic emergency-parking brakes.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Automatic emergency-parking brakes. 75.523-3...-3 Automatic emergency-parking brakes. (a) Except for personnel carriers, rubber-tired, self... with automatic emergency-parking brakes in accordance with the following schedule. (1) On and after May...

30 CFR 75.523-3 - Automatic emergency-parking brakes.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Automatic emergency-parking brakes. 75.523-3...-3 Automatic emergency-parking brakes. (a) Except for personnel carriers, rubber-tired, self... with automatic emergency-parking brakes in accordance with the following schedule. (1) On and after May...

49 CFR 232.103 - General requirements for all train brake systems.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the air compressor governor starting or loading pressure. (l) Except as otherwise provided in this... brake pipe air pressure: Road Service 90 Switch Service 60 (2) Minimum differential between brake pipe and main reservoir air pressures, with brake valve in running position 15 (3) Safety valve for...

49 CFR 232.103 - General requirements for all train brake systems.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the air compressor governor starting or loading pressure. (l) Except as otherwise provided in this... brake pipe air pressure: Road Service 90 Switch Service 60 (2) Minimum differential between brake pipe and main reservoir air pressures, with brake valve in running position 15 (3) Safety valve for...

Feasibility of Onboard Processing of Heuristic Path Planning and Navigation Algorithms within SUAS Autopilot Computational Constraints

DTIC Science & Technology

2014-03-01

brake_group > NONE </ brake_group > <retractable>0</retractable> </contact> <contact type="BOGEY" name="RIGHT_MLG...damping_coeff> <max_steer unit="DEG"> 0.0 </max_steer> < brake_group > NONE </ brake_group > <retractable>0</retractable...damping_coeff unit="LBS/FT/SEC"> 100 </damping_coeff> <max_steer unit="DEG"> 360.0 </max_steer> < brake_group > NONE

Heat loading of hoist brakes by example of drum brakes

NASA Astrophysics Data System (ADS)

Vöth, S.; Vasilyeva, M. A.

2017-10-01

Due to the technological development in drive technology, drives controlled by frequency inverters in hoists of cranes are almost standard. Since these drives offer the possibility of electric braking, the operation of the mechanical brakes changes as a result. As a result, the mechanical brakes are used more rarely and, if so, more likely in critical operating conditions. In this paper, an analysis of the changes that occur in the structure under the influence of thermal load is presented.

Dynamics of aircraft antiskid braking systems. [conducted at the Langley aircraft landing loads and traction facility

NASA Technical Reports Server (NTRS)

Tanner, J. A.; Stubbs, S. M.; Dreher, R. C.; Smith, E. G.

1982-01-01

A computer study was performed to assess the accuracy of three brake pressure-torque mathematical models. The investigation utilized one main gear wheel, brake, and tire assembly of a McDonnell Douglas DC-9 series 10 airplane. The investigation indicates that the performance of aircraft antiskid braking systems is strongly influenced by tire characteristics, dynamic response of the antiskid control valve, and pressure-torque response of the brake. The computer study employed an average torque error criterion to assess the accuracy of the models. The results indicate that a variable nonlinear spring with hysteresis memory function models the pressure-torque response of the brake more accurately than currently used models.

Improvement microstructural and damage characterization of ceramic composites Y{sub 2}O{sub 3} – V{sub 2}O{sub 5} with MgO nano particles

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

Issa, T. T., E-mail: alazbrh@yahoo.com; Hasan, J. M.; Abdullah, E. T.

2016-04-21

Compacted samples of Y{sub 2}O{sub 3}-V{sub 2}O{sub 5} – MgO Nano – particles wt. % sintered at different sintering temperature (700, 900, 1100, 1300) ) C° for 2 hours under static air were investigated by x-ray diffraction and differential thermal analysis(DTA), to identify the phase present .Microstructure examination achieved by scanning electron microscopy .Sintered density and porosity were measured for all sintered samples .Compression was tested too and the Brake down voltage and dielectric strength were measure for all sintered samples .The clear improvement were noticed in both microstructure and damage characterization respectively after existing the MgO Nano-particles, by increasingmore » in about 30% in sintered density and 25% for the compressive strength .The improvement also noticed on both brake down voltage and dielectric strength.« less

Hidden Markov model tracking of continuous gravitational waves from young supernova remnants

NASA Astrophysics Data System (ADS)

Sun, L.; Melatos, A.; Suvorova, S.; Moran, W.; Evans, R. J.

2018-02-01

Searches for persistent gravitational radiation from nonpulsating neutron stars in young supernova remnants are computationally challenging because of rapid stellar braking. We describe a practical, efficient, semicoherent search based on a hidden Markov model tracking scheme, solved by the Viterbi algorithm, combined with a maximum likelihood matched filter, the F statistic. The scheme is well suited to analyzing data from advanced detectors like the Advanced Laser Interferometer Gravitational Wave Observatory (Advanced LIGO). It can track rapid phase evolution from secular stellar braking and stochastic timing noise torques simultaneously without searching second- and higher-order derivatives of the signal frequency, providing an economical alternative to stack-slide-based semicoherent algorithms. One implementation tracks the signal frequency alone. A second implementation tracks the signal frequency and its first time derivative. It improves the sensitivity by a factor of a few upon the first implementation, but the cost increases by 2 to 3 orders of magnitude.

Biomechanical energy harvesting: generating electricity during walking with minimal user effort.

PubMed

Donelan, J M; Li, Q; Naing, V; Hoffer, J A; Weber, D J; Kuo, A D

2008-02-08

We have developed a biomechanical energy harvester that generates electricity during human walking with little extra effort. Unlike conventional human-powered generators that use positive muscle work, our technology assists muscles in performing negative work, analogous to regenerative braking in hybrid cars, where energy normally dissipated during braking drives a generator instead. The energy harvester mounts at the knee and selectively engages power generation at the end of the swing phase, thus assisting deceleration of the joint. Test subjects walking with one device on each leg produced an average of 5 watts of electricity, which is about 10 times that of shoe-mounted devices. The cost of harvesting-the additional metabolic power required to produce 1 watt of electricity-is less than one-eighth of that for conventional human power generation. Producing substantial electricity with little extra effort makes this method well-suited for charging powered prosthetic limbs and other portable medical devices.

Development of friction material by using precast prefired (pcp f) blocks

NASA Astrophysics Data System (ADS)

Dineshkumar, R.; Ramanamurthy, E. V. V.; Krishnapavanteja, Ch

2017-05-01

The braking system used to control and stop automobile system. The braking system converts the kinematic energy into heat energy by friction. The performance of the brake pad depends on composition of friction materials. The asbestos brake pads are carcinogenic nature and it makes so many health problems. The present research work is going to replacement of asbestos by new materials. The new material is made by fused ceramic materials from industrial wastage. In this study the industrial waste are recycled and conducted the suitable test to compare the performance of the new material with existing brake pad material. The wear test was conducted by pin on disc experiment. The non asbestos, nonfused, fused samples are represented by x1, x2 and x3. The new brake pad material is formed by non fused and fused ceramic materials. The brake pads are manufactured by powder compacting process.

In-depth analysis of bicycle hydraulic disc brakes

NASA Astrophysics Data System (ADS)

Maier, Oliver; Györfi, Benedikt; Wrede, Jürgen; Arnold, Timo; Moia, Alessandro

2017-10-01

Hydraulic Disc Brakes (HDBs) represent the most recent and innovative bicycle braking system. Especially Electric Bicycles (EBs), which are becoming more and more popular, are equipped with this powerful, unaffected by environmental influences, and low-wear type of brakes. As a consequence of the high braking performance, typical bicycle braking errors lead to more serious accidents. This is the starting point for the development of a Braking Dynamics Assistance system (BDA) to prevent front wheel lockup and nose-over (falling over the handlebars). One of the essential prerequisites for the system design is a better understanding of bicycle HDBs' characteristics. A physical simulation model and a test bench have been built for this purpose. The results of the virtual and real experiments conducted show a high correlation and allow valuable insights into HDBs on bicycles, which have not been studied scientifically in any depth so far.

75 FR 26841 - Petition for Waiver of Compliance

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-12

... initiating a full service brake application in the event of a hardware or software failure that could impair the ability of the engineer to apply or release the brakes or; (ii) Access to direct manual control of... petition that the full service brake application is transmitted electronically to each MU's Friction Brake...

30 CFR 75.1404-1 - Braking system.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Braking system. 75.1404-1 Section 75.1404-1... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1404-1 Braking system. A locomotive equipped with a dual braking system will be deemed to satisfy the requirements of § 75.1404 for a...

30 CFR 75.1404-1 - Braking system.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Braking system. 75.1404-1 Section 75.1404-1... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Hoisting and Mantrips § 75.1404-1 Braking system. A locomotive equipped with a dual braking system will be deemed to satisfy the requirements of § 75.1404 for a...

49 CFR 238.15 - Movement of passenger equipment with power brake defects.

Code of Federal Regulations, 2010 CFR

2010-10-01

... brakes; (C) Piston travel that is in excess of the Class I brake test limits required in § 238.313 but... where the necessary repairs can be made. (3) Commuter, short-distance intercity, and short-distance Tier... brakes. Commuter, short-distance intercity, and short-distance Tier II passenger trains which develop...

49 CFR 236.508 - Interference with application of brakes by means of brake valve.

Code of Federal Regulations, 2011 CFR

2011-10-01

... GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.508 Interference with application of brakes by means of brake valve. The automatic train stop, train control, or...

49 CFR 236.508 - Interference with application of brakes by means of brake valve.

Code of Federal Regulations, 2010 CFR

2010-10-01

... GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.508 Interference with application of brakes by means of brake valve. The automatic train stop, train control, or...

49 CFR 238.315 - Class IA brake test.

Code of Federal Regulations, 2013 CFR

2013-10-01

... that utilize an electric signal to communicate a service brake application and only a pneumatic signal... and release of the brakes on the last car in the train; and (6) The communicating signal system is... be used to verify the set and release on cars so equipped. However, the observation of the brake...

49 CFR 238.315 - Class IA brake test.

Code of Federal Regulations, 2014 CFR

2014-10-01

... that utilize an electric signal to communicate a service brake application and only a pneumatic signal... and release of the brakes on the last car in the train; and (6) The communicating signal system is... be used to verify the set and release on cars so equipped. However, the observation of the brake...

An Instructor's Guide for a Program in Brake Services.

ERIC Educational Resources Information Center

New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

The instructor's guide is designed to present an understanding of the automotive hydraulic brake system and to help individuals develop new skills for employment in this specialized field of automotive service. Applicable for secondary or adult education, this guide describes: the brake system, types of brakes, diagnosis and correction of brake…

49 CFR 570.6 - Brake power unit.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 6 2011-10-01 2011-10-01 false Brake power unit. 570.6 Section 570.6... Pounds or Less § 570.6 Brake power unit. (a) Vacuum hoses shall not be collapsed, abraded, broken... power assist system. This test is not applicable to vehicles equipped with full power brake system as...

49 CFR 238.315 - Class IA brake test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... that utilize an electric signal to communicate a service brake application and only a pneumatic signal... and release of the brakes on the last car in the train; and (6) The communicating signal system is... be used to verify the set and release on cars so equipped. However, the observation of the brake...

49 CFR 232.503 - Process to introduce new brake system technology.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false Process to introduce new brake system technology... Technology § 232.503 Process to introduce new brake system technology. (a) Pursuant to the procedures... brake system technology, prior to implementing the plan. (b) Each railroad shall complete a pre-revenue...

49 CFR 232.503 - Process to introduce new brake system technology.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false Process to introduce new brake system technology... Technology § 232.503 Process to introduce new brake system technology. (a) Pursuant to the procedures... brake system technology, prior to implementing the plan. (b) Each railroad shall complete a pre-revenue...

49 CFR 232.503 - Process to introduce new brake system technology.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 4 2012-10-01 2012-10-01 false Process to introduce new brake system technology... Technology § 232.503 Process to introduce new brake system technology. (a) Pursuant to the procedures... brake system technology, prior to implementing the plan. (b) Each railroad shall complete a pre-revenue...

49 CFR 232.503 - Process to introduce new brake system technology.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Process to introduce new brake system technology... Technology § 232.503 Process to introduce new brake system technology. (a) Pursuant to the procedures... brake system technology, prior to implementing the plan. (b) Each railroad shall complete a pre-revenue...

Compact, Lightweight Servo-Controllable Brakes

NASA Technical Reports Server (NTRS)

Lovchik, Christopher S.; Townsend, William; Guertin, Jeffrey; Matsuoka, Yoky

2010-01-01

Compact, lightweight servo-controllable brakes capable of high torques are being developed for incorporation into robot joints. A brake of this type is based partly on the capstan effect of tension elements. In a brake of the type under development, a controllable intermediate state of torque is reached through on/off switching at a high frequency.

49 CFR 393.48 - Brakes to be operative.

Code of Federal Regulations, 2010 CFR

2010-10-01

... motor vehicle may be equipped with a device to reduce the front wheel braking effort (or in the case of... operable by the driver except upon application of the control that activates the braking system. The device... with air brakes) or 85 percent of the maximum system pressure (for vehicles which are not equipped with...

49 CFR 238.319 - Running brake test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Running brake test. 238.319 Section 238.319... Requirements for Tier I Passenger Equipment § 238.319 Running brake test. (a) As soon as conditions safely permit, a running brake test shall be performed on each passenger train after the train has received, or...

49 CFR 238.319 - Running brake test.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Running brake test. 238.319 Section 238.319... Requirements for Tier I Passenger Equipment § 238.319 Running brake test. (a) As soon as conditions safely permit, a running brake test shall be performed on each passenger train after the train has received, or...

16 CFR § 1512.5 - Requirements for braking system.

Code of Federal Regulations, 2013 CFR

2013-01-01

... the braking force transmitted to the rear wheel shall be in accordance with the sidewalk bicycle.... Bicycles shall be equipped with front- and rear-wheel brakes or rear-wheel brakes only. (b) Handbrakes. Handbrakes shall be tested at least ten times by applying a force sufficient to cause the handlever to...

49 CFR 232.503 - Process to introduce new brake system technology.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Process to introduce new brake system technology... Technology § 232.503 Process to introduce new brake system technology. (a) Pursuant to the procedures... brake system technology, prior to implementing the plan. (b) Each railroad shall complete a pre-revenue...

Gas-Dynamic Designing of the Exhaust System for the Air Brake

NASA Astrophysics Data System (ADS)

Novikova, Yu; Goriachkin, E.; Volkov, A.

2018-01-01

Each gas turbine engine is tested some times during the life-cycle. The test equipment includes the air brake that utilizes the power produced by the gas turbine engine. In actual conditions, the outlet pressure of the air brake does not change and is equal to atmospheric pressure. For this reason, for the air brake work it is necessary to design the special exhaust system. Mission of the exhaust system is to provide the required level of backpressure at the outlet of the air brake. The backpressure is required for the required power utilization by the air brake (the air brake operation in the required points on the performance curves). The paper is described the development of the gas dynamic canal, designing outlet guide vane and the creation of a unified exhaust system for the air brake. Using a unified exhaust system involves moving the operating point to the performance curve further away from the calculated point. However, the applying of one exhaust system instead of two will significantly reduce the cash and time costs.

A Study on Rotordynamic Characteristics of Swirl Brakes for Three Types of Seals

NASA Astrophysics Data System (ADS)

Xu, Wanjun; Yang, Jiangang

2017-03-01

In order to understand swirl brakes mechanisms and their influence on rotordynamic characteristics for different types of seals, a three-dimensional flow numerical simulation was presented. Three typical seals including labyrinth seal, fully partitioned damper seal and hole-pattern seal were compared under three inlet conditions of no preswirl, preswirl and preswirl with swirl brakes. FAN boundary condition was used to provide inlet preswirl. A modified identification method of effective damping was proposed. Feasibility of the swirl brakes on improving performance of damper seals was discussed. The results show that the swirl brakes influence the seal stability characteristics with whirl frequency. For the labyrinth seal the swirl brakes reverse the sign of effective damping at low frequency and improve the seal stability performance in a wide frequency range. The swirl brakes also improve the damper seals’ stability performance by increasing the low frequency effective damping and reducing their crossover frequency. Further results indicate the swirl brakes affect the rotational direction of the maximum (minimum) pressure positions and enhance the stability of the seals by reducing tangential force in each cavity.

Wheel slip control with torque blending using linear and nonlinear model predictive control

NASA Astrophysics Data System (ADS)

Basrah, M. Sofian; Siampis, Efstathios; Velenis, Efstathios; Cao, Dongpu; Longo, Stefano

2017-11-01

Modern hybrid electric vehicles employ electric braking to recuperate energy during deceleration. However, currently anti-lock braking system (ABS) functionality is delivered solely by friction brakes. Hence regenerative braking is typically deactivated at a low deceleration threshold in case high slip develops at the wheels and ABS activation is required. If blending of friction and electric braking can be achieved during ABS events, there would be no need to impose conservative thresholds for deactivation of regenerative braking and the recuperation capacity of the vehicle would increase significantly. In addition, electric actuators are typically significantly faster responding and would deliver better control of wheel slip than friction brakes. In this work we present a control strategy for ABS on a fully electric vehicle with each wheel independently driven by an electric machine and friction brake independently applied at each wheel. In particular we develop linear and nonlinear model predictive control strategies for optimal performance and enforcement of critical control and state constraints. The capability for real-time implementation of these controllers is assessed and their performance is validated in high fidelity simulation.

Optimization of diesel engine performance by the Bees Algorithm

NASA Astrophysics Data System (ADS)

Azfanizam Ahmad, Siti; Sunthiram, Devaraj

2018-03-01

Biodiesel recently has been receiving a great attention in the world market due to the depletion of the existing fossil fuels. Biodiesel also becomes an alternative for diesel No. 2 fuel which possesses characteristics such as biodegradable and oxygenated. However, there are facts suggested that biodiesel does not have the equivalent features as diesel No. 2 fuel as it has been claimed that the usage of biodiesel giving increment in the brake specific fuel consumption (BSFC). The objective of this study is to find the maximum brake power and brake torque as well as the minimum BSFC to optimize the condition of diesel engine when using the biodiesel fuel. This optimization was conducted using the Bees Algorithm (BA) under specific biodiesel percentage in fuel mixture, engine speed and engine load. The result showed that 58.33kW of brake power, 310.33 N.m of brake torque and 200.29/(kW.h) of BSFC were the optimum value. Comparing to the ones obtained by other algorithm, the BA produced a fine brake power and a better brake torque and BSFC. This finding proved that the BA can be used to optimize the performance of diesel engine based on the optimum value of the brake power, brake torque and BSFC.

Chaos in brake squeal noise

NASA Astrophysics Data System (ADS)

Oberst, S.; Lai, J. C. S.

2011-02-01

Brake squeal has become an increasing concern to the automotive industry because of warranty costs and the requirement for continued interior vehicle noise reduction. Most research has been directed to either analytical and experimental studies of brake squeal mechanisms or the prediction of brake squeal propensity using finite element methods. By comparison, there is a lack of systematic analysis of brake squeal data obtained from a noise dynamometer. It is well known that brake squeal is a nonlinear transient phenomenon and a number of studies using analytical and experimental models of brake systems (e.g., pin-on-disc) indicate that it could be treated as a chaotic phenomenon. Data obtained from a full brake system on a noise dynamometer were examined with nonlinear analysis techniques. The application of recurrence plots reveals chaotic structures even in noisy data from the squealing events. By separating the time series into different regimes, lower dimensional attractors are isolated and quantified by dynamic invariants such as correlation dimension estimates or Lyapunov exponents. Further analysis of the recurrence plot of squealing events by means of recurrence quantification analysis measures reveals different regimes of laminar and random behaviour, periodicity and chaos-forming recurrent transitions. These results help to classify brake squeal mechanisms and to enhance understanding of friction-related noise phenomena.

Why Do the Braking Indices of Pulsars Span a Range of More Than 100 Millions?

NASA Astrophysics Data System (ADS)

Zhang, Shuang-Nan; Xie, Yi

2012-12-01

Here we report that the observed braking indices of the 366 pulsars in the sample of Hobbs et al. range from about -108 to about +108 and are significantly correlated with their characteristic ages. Using the model of magnetic field evolution we developed previously based on the same data, we derive an analytical expression for the braking index which agrees with all the observed statistical properties of the braking indices of the pulsars in the sample of Hobbs et al. Our model is, however, incompatible with the previous interpretation that magnetic field growth is responsible for the small values of braking indices (<3) observed for "baby" pulsars with characteristic ages of less than 2 × 103 yr. We find that the "instantaneous" braking index of a pulsar may be different from the "averaged" braking index obtained from fitting the data over a certain time span. The close match between our model-predicted "instantaneous" braking indices and the observed "averaged" braking indices suggests that the time spans used previously are usually smaller than or comparable to their magnetic field oscillation periods. Our model can be tested with the existing data by calculating the braking index as a function of the time span for each pulsar. In doing so, one can obtain for each pulsar all the parameters in our magnetic field evolution model, and may be able to improve the sensitivity of using pulsars to detect gravitational waves.

Numerical Investigation of Aerodynamic Braking for a Ground Vehicle

NASA Astrophysics Data System (ADS)

Devanuri, Jaya Krishna

2018-06-01

The purpose of this article is to observe the effect of an air brake on the aerodynamics of a ground vehicle and also to study the influence of change in the parameters like the velocity of the vehicle, the angle of inclination, height, and position of the air brake on the aerodynamics of the vehicle body. The test subject used is an Ahmed body which is a generic 3D car body as it retains all the aerodynamic characteristics of a ground vehicle. Numerical investigation has been carried out by RNG k-ɛ turbulence model. Results are presented in terms of streamlines and drag coefficient to understand the influence of pertinent parameters on flow physics. It is found that with the use of an air brake, though the drag coefficient remains more or less constant with velocity, it increases with the increase in height and angle of inclination of the air brake. But the effect of position of air brake on the coefficient of drag is surprising since for certain heights of the air brake the drag coefficient is maximum at the foremost point and as the air brake moves towards the rear it is first observed to decrease and then increase. It is also observed that with the increase in height of the air brake the drag coefficient monotonically decreases as the position of the air brake is moved towards the rear. Taguchi method has been employed with L16 orthogonal array to obtain the optimal configuration for the air brake. For each of the selected parameters, four different levels have been chosen to obtain the maximum drag coefficient value. The study could provide an invaluable database for the optimal design of an airbrake for a ground vehicle.

Diabetic Driving Studies-Part 2: A Comparison of Brake Response Time Between Drivers With Diabetes With and Without Lower Extremity Sensorimotor Neuropathy.

PubMed

Spiess, Kerianne E; Sansosti, Laura E; Meyr, Andrew J

We have previously demonstrated an abnormally delayed mean brake response time and an increased frequency of abnormally delayed brake responses in a group of neuropathic drivers with diabetes compared with a control group of drivers with neither diabetes nor lower extremity neuropathy. The objective of the present case-control study was to compare the mean brake response time between 2 groups of drivers with diabetes with and without lower extremity sensorimotor neuropathy. The braking performances of the participants were evaluated using a computerized driving simulator with specific measurement of the mean brake response time and the frequency of the abnormally delayed brake responses. We compared a control group of 25 active drivers with type 2 diabetes without lower extremity neuropathy and an experimental group of 25 active drivers with type 2 diabetes and lower extremity neuropathy from an urban U.S. podiatric medical clinic. The experimental group demonstrated an 11.49% slower mean brake response time (0.757 ± 0.180 versus 0.679 ± 0.120 second; p < .001), with abnormally delayed reactions occurring at a greater frequency (57.5% versus 35.0%; p < .001). Independent of a comparative statistical analysis, diabetic drivers with neuropathy demonstrated a mean brake response time slower than a suggested safety threshold of 0.70 second, and diabetic drivers without neuropathy demonstrated a mean brake response time faster than this threshold. The results of the present investigation provide evidence that the specific onset of lower extremity sensorimotor neuropathy associated with diabetes appears to impart a negative effect on automobile brake responses. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Evaluation of the fate and pathological response in the lung and pleura of brake dust alone and in combination with added chrysotile compared to crocidolite asbestos following short-term inhalation exposure

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

Bernstein, D.M., E-mail: davidb@itox.ch; Rogers, R.A., E-mail: rarogers5@yahoo.com; Sepulveda, R.

This study was designed to provide an understanding of the biokinetics and potential toxicology in the lung and pleura following inhalation of brake dust following short term exposure in rats. The deposition, translocation and pathological response of brake-dust derived from brake pads manufactured with chrysotile were evaluated in comparison to the amphibole, crocidolite asbestos. Rats were exposed by inhalation 6 h/day for 5 days to either brake-dust obtained by sanding of brake-drums manufactured with chrysotile, a mixture of chrysotile and the brake-dust or crocidolite asbestos. The chrysotile fibers were relatively biosoluble whereas the crocidolite asbestos fibers persisted through the life-timemore » of the animal. This was reflected in the lung and the pleura where no significant pathological response was observed at any time point in the brake dust or chrysotile/brake dust exposure groups through 365 days post exposure. In contrast, crocidolite asbestos produced a rapid inflammatory response in the lung parenchyma and the pleura, inducing a significant increase in fibrotic response in both of these compartments. Crocidolite fibers were observed embedded in the diaphragm with activated mesothelial cells immediately after cessation of exposure. While no chrysotile fibers were found in the mediastinal lymph nodes, crocidolite fibers of up to 35 μm were observed. These results provide support that brake-dust derived from chrysotile containing brake drums would not initiate a pathological response in the lung or the pleural cavity following short term inhalation. - Highlights: • Evaluated brake dust w/wo added chrysotile in comparison to crocidolite asbestos. • Persistence, translocation, pathological response in the lung and pleural cavity. • Chrysotile cleared rapidly from the lung while the crocidolite asbestos persisted. • No significant pathology in lung or pleural cavity observed at any time point in the brake-dust groups. • Crocidolite quickly produced pathological response in the lung and pleural cavity.« less

Improved Electromagnetic Brake

NASA Technical Reports Server (NTRS)

Martin, Toby B.

2004-01-01

A proposed design for an electromagnetic brake would increase the reliability while reducing the number of parts and the weight, relative to a prior commercially available electromagnetic brake. The reductions of weight and the number of parts could also lead to a reduction of cost. A description of the commercial brake is prerequisite to a description of the proposed electromagnetic brake. The commercial brake (see upper part of figure) includes (1) a permanent magnet and an electromagnet coil on a stator and (2) a rotor that includes a steel contact plate mounted, with tension spring loading, on an aluminum hub. The stator is mounted securely on a stationary object, which would ordinarily be the housing of a gear drive or a motor. The rotor is mounted on the shaft of the gear drive or motor. The commercial brake nominally operates in a fail-safe (in the sense of normally braking) mode: In the absence of current in the electromagnet coil, the permanent magnet pulls the contact plate, against the spring tension, into contact with the stator. To release the brake, one excites the electromagnet with a current of the magnitude and polarity chosen to cancel the magnetic flux of the permanent magnet, thereby enabling the spring tension to pull the contact plate out of contact with the stator. The fail-safe operation of the commercial brake depends on careful mounting of the rotor in relation to the stator. The rotor/stator gap must be set with a tolerance between 10 and 15 mils (between about 0.25 and about 0.38 mm). If the gap or the contact pad is thicker than the maximum allowable value, then the permanent magnetic field will not be strong enough to pull the steel plate across the gap. (For this reason, any contact pad between the contact plate and the stator must also be correspondingly thin.) If the gap exceeds the maximum allowable value because of shaft end play, it becomes impossible to set the brake by turning off the electromagnet current. Although it may still be possible to set the brake by applying an electromagnet current to aid the permanent magnetic field instead of canceling it, this action can mask an out-of-tolerance condition in the brake and it does not restore the fail-safe function of setting the brake when current is lost.

Magnetostatic simulation on a novel design of axially multi-coiled magnetorheological brakes

NASA Astrophysics Data System (ADS)

Ubaidillah, Permata, A. N. S.; Wibowo, A.; Budiana, E. P.; Yahya, I.; Mazlan, S. A.

2016-03-01

This paper describes the 3D magnetostatic simulation of a novel design axially multi-coiled magnetorheological (MRB). The proposed model is expected to produce a concentrated magnetic flux on the surface of the rotor disk brake. Thus, the braking torque enhancement is expected to be higher than that of conventional big size single-coil-equipped disk-type MRB. The axially multi-coiled MRB design features multiple electromagnetic poles from by several coils placed in the axial direction outside the MRB body. The magnetostatic analysis was developed utilizing finite element software namely ANSOFT-MAXWELL in 3D environment. The distribution of magnetic flux was investigated in a pair of the coil that represents the other pairs of electromagnetic parts. The simulation was done in 0.5 mm gap filled by magnetorheological fluids (MRFs) (MRF-132DG). The simulation was performed in various applied currents i.e. 0.25, 0.5, 0.75, 1, 1.5, and 2 Amperes. The results showed that the axially multi-coiled MRB provides a considerable magnetic flux (maximum of 337 mT/area). The active energizing areas of the MRB are proven to be more intensive than the conventional MRB. The proposed MRB exhibited a compact and robust design for achieving high torque MRB.

Stride length: the impact on propulsion and bracing ground reaction force in overhand throwing.

PubMed

Ramsey, Dan K; Crotin, Ryan L

2018-03-26

Propulsion and bracing ground reaction force (GRF) in overhand throwing are integral in propagating joint reaction kinetics and ball velocity, yet how stride length effects drive (hind) and stride (lead) leg GRF profiles remain unknown. Using a randomised crossover design, 19 pitchers (15 collegiate and 4 high school) were assigned to throw 2 simulated 80-pitch games at ±25% of their desired stride length. An integrated motion capture system with two force plates and radar gun tracked each throw. Vertical and anterior-posterior GRF was normalised then impulse was derived. Paired t-tests identified whether differences between conditions were significant. Late in single leg support, peak propulsion GRF was statistically greater for the drive leg with increased stride. Stride leg peak vertical GRF in braking occurred before acceleration with longer strides, but near ball release with shorter strides. Greater posterior shear GRF involving both legs demonstrated increased braking with longer strides. Conversely, decreased drive leg propulsion reduced both legs' braking effects with shorter strides. Results suggest an interconnection between normalised stride length and GRF application in propulsion and bracing. This work has shown stride length to be an important kinematic factor affecting the magnitude and timing of external forces acting upon the body.

75 FR 63042 - Airworthiness Directives; Fokker Services B.V. Model F.28 Mark 0070 and 0100 Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-14

...: * * * * * Recently, a brake fire was reported which was caused by a ruptured brake piston. The fire was quickly... investigation showed that a hydraulic lock must have been present close to the affected brake creating enough... (not necessarily disconnected) brake QD [quick-disconnect] coupling. Further investigation of the...

49 CFR 238.315 - Class IA brake test.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Class IA brake test. 238.315 Section 238.315... Requirements for Tier I Passenger Equipment § 238.315 Class IA brake test. (a) Except as provided in paragraph (b) of this section, either a Class I or a Class IA brake test shall be performed: (1) Prior to the...

49 CFR 214.529 - In-service failure of primary braking system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 4 2014-10-01 2014-10-01 false In-service failure of primary braking system. 214... Maintenance Machines and Hi-Rail Vehicles § 214.529 In-service failure of primary braking system. (a) In the event of a total in-service failure of its primary braking system, an on-track roadway maintenance...

49 CFR 214.529 - In-service failure of primary braking system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 4 2013-10-01 2013-10-01 false In-service failure of primary braking system. 214... Maintenance Machines and Hi-Rail Vehicles § 214.529 In-service failure of primary braking system. (a) In the event of a total in-service failure of its primary braking system, an on-track roadway maintenance...

75 FR 49365 - Airworthiness Directives; BAE Systems (Operations) Limited Model BAe 146-100A and -200A Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-13

... lift to ensure that the wheel brakes can provide the necessary speed reduction. * * * * * The effects... brakes can provide the necessary speed reduction. A review of the changing operational profile of the... landing to provide aerodynamic braking and to dump lift to ensure that the wheel brakes can provide the...

49 CFR 214.529 - In-service failure of primary braking system.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Maintenance Machines and Hi-Rail Vehicles § 214.529 In-service failure of primary braking system. (a) In the event of a total in-service failure of its primary braking system, an on-track roadway maintenance... 49 Transportation 4 2010-10-01 2010-10-01 false In-service failure of primary braking system. 214...

49 CFR 232.103 - General requirements for all train brake systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

... pneumatic technology, the integrity of the train line shall be monitored by the brake control system. (c) A... train shall not move if less than 85 percent of the cars in that train have operative and effective brakes. (f) Each car in a train shall have its air brakes in effective operating condition unless the car...

49 CFR 570.5 - Service brake system.

Code of Federal Regulations, 2012 CFR

2012-10-01

... force applied by the brake on a front wheel or a rear wheel shall not differ by more than 20 percent from the force applied by the brake on the other front wheel or the other rear wheel respectively. (i... Pounds or Less § 570.5 Service brake system. Unless otherwise noted, the force to be applied during...

49 CFR 570.5 - Service brake system.

Code of Federal Regulations, 2014 CFR

2014-10-01

... force applied by the brake on a front wheel or a rear wheel shall not differ by more than 20 percent from the force applied by the brake on the other front wheel or the other rear wheel respectively. (i... Pounds or Less § 570.5 Service brake system. Unless otherwise noted, the force to be applied during...

49 CFR 570.5 - Service brake system.

Code of Federal Regulations, 2013 CFR

2013-10-01

... force applied by the brake on a front wheel or a rear wheel shall not differ by more than 20 percent from the force applied by the brake on the other front wheel or the other rear wheel respectively. (i... Pounds or Less § 570.5 Service brake system. Unless otherwise noted, the force to be applied during...

49 CFR 232.205 - Class I brake test-initial terminal inspection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... test shall be conducted as follows: (A) Charge the air brake system to the pressure at which the train... equivalent pressure maintaining locomotive brake valve, a railroad may use the Air Flow Method Test as an...) Charge the air brake system to the pressure at which the train will be operated, and the pressure at the...

49 CFR 232.205 - Class I brake test-initial terminal inspection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... test shall be conducted as follows: (A) Charge the air brake system to the pressure at which the train... equivalent pressure maintaining locomotive brake valve, a railroad may use the Air Flow Method Test as an...) Charge the air brake system to the pressure at which the train will be operated, and the pressure at the...

49 CFR 232.205 - Class I brake test-initial terminal inspection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... test shall be conducted as follows: (A) Charge the air brake system to the pressure at which the train... equivalent pressure maintaining locomotive brake valve, a railroad may use the Air Flow Method Test as an...) Charge the air brake system to the pressure at which the train will be operated, and the pressure at the...

49 CFR 232.205 - Class I brake test-initial terminal inspection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... test shall be conducted as follows: (A) Charge the air brake system to the pressure at which the train... equivalent pressure maintaining locomotive brake valve, a railroad may use the Air Flow Method Test as an...) Charge the air brake system to the pressure at which the train will be operated, and the pressure at the...

Defense Supplier Base: DOD Should Leverage Ongoing Initiatives in Developing Its Program to Mitigate Risk of Counterfeit Parts

DTIC Science & Technology

2010-03-01

titanium, used in fighter jet engine mounts. Brake shoes Brake shoes were made with substandard materials, including seaweed . Source: DOD. DOD does...company. These brake shoes were made with various materials, including seaweed . U.S. customs agents had already seized the brake shoes and DOD never

Bidirectional Drive-And-Brake Mechanism

NASA Technical Reports Server (NTRS)

Swan, Scott A.

1991-01-01

Vehicle that crawls along monorail combines features of both bicycle and railroad handcar. Bidirectional drive-and-brake mechanism includes selectable-pawl-and-ratchet overrunning clutch (drive mechanism) and mating stationary and rotating conical surfaces pressing against each other (brake mechanism). Operates similarly to bicycle drive-and-brake mechanism except limits rotation of sprocket in both directions and brakes at both limits. Conceived for use by astronaut traveling along structure in outer space, concept also applied on Earth to make very small railraod handcars or crawling vehicles for use on large structures, in pipelines under construction, or underwater.

The process of gas-dynamic design of pneumatic braking system using the baseline compressor

NASA Astrophysics Data System (ADS)

Novikova, Y.; Popov, G.; Goriachkin, E.; Baturin, O.; Zubanov, V.

2017-08-01

The article presents the results of work on the design of the air brake for testing of industrial gas turbine engines with free turbine. Designing of the air brake was performed on the basis of existing units using the program CFD - simulation Numeca FineTurbo. During the design the air brake arrangement was determined, which allows to utilize the required power to the shaft of the free turbine, increases stall margin of the air brake by waisting of the meridional flow channel. It was also made designing of the outlet guide vane to remove the residual twist. Unified nozzle also was designed to provide the air brake work at necessary points on the characteristic.

Common drive unit

NASA Technical Reports Server (NTRS)

Ellis, R. C.; Fink, R. A.; Moore, E. A.

1987-01-01

The Common Drive Unit (CDU) is a high reliability rotary actuator with many versatile applications in mechanism designs. The CDU incorporates a set of redundant motor-brake assemblies driving a single output shaft through differential. Tachometers provide speed information in the AC version. Operation of both motors, as compared to the operation of one motor, will yield the same output torque with twice the output speed.

Why Blue stragglers formed via collisions may not be rapid rotators

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

Leonard, P.J.T.; Clement, M.J.

1993-03-01

We propose that the blue stragglers formed via collisions may not be rapid rotators due to magnetic braking during a Hayashi phase as they approach the main sequence. It is conceivable that just the envelopes of the blue stragglers are spun down, while their cores remain rapidly rotating. This would greatly extend the main-sequence lifetimes of the blue stragglers produced by collisions.

Why Blue stragglers formed via collisions may not be rapid rotators

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

Leonard, P.J.T.; Clement, M.J.

1993-01-01

We propose that the blue stragglers formed via collisions may not be rapid rotators due to magnetic braking during a Hayashi phase as they approach the main sequence. It is conceivable that just the envelopes of the blue stragglers are spun down, while their cores remain rapidly rotating. This would greatly extend the main-sequence lifetimes of the blue stragglers produced by collisions.

Kinematic algorithm to determine the energy cost of running with changes of direction.

PubMed

Zago, Matteo; Esposito, Fabio; Rausa, Giulia; Limonta, Eloisa; Corrado, Felice; Rampichini, Susanna; Sforza, Chiarella

2018-06-15

Changes of direction (CoDs) have a high metabolic and mechanical impact in field and court team sports, but the estimation of the associated workload is still inaccurate. This study aims at validating an algorithm based on kinematic data to estimate the energy cost of running with frequent 180°-CoDs. Twenty-six physically active male subjects (22.4 ± 3.2 years) participated in two sessions: (1) maximum oxygen uptake (V̇O 2,max ) and maximal aerobic speed (MAS) test; (2) 5-m continuous shuttle run (two 5-min trials at 50% and 75% MAS, 6-min recovery). In (2), full-body 3D-kinematics and V̇O 2 were simultaneously recorded. Actual cost of shuttle running (C meas ) was obtained from the aerobic, anaerobic alactic and lactic components. The proposed algorithm detects "braking phases", periods of mostly negative (eccentric) work occurring at concurrent knee flexion and ground contact, and estimates energy cost (C est ) considering negative mechanical work in braking phases, and positive elsewhere. At the speed of, respectively, 1.54 ± 0.17 and 1.90 ± 0.15 m s -1 (rate of perceived exertion: 9.1 ± 1.8 and 15.8 ± 1.9), C meas was 8.06 ± 0.49 and 9.04 ± 0.73 J kg -1  m -1 . C est was more accurate than regression models found in literature (p < 0.01), and not significantly different from C meas (p > 0.05; average error: 8.3%, root-mean-square error: 0.86 J kg -1  m -1 ). The proposed algorithm improved existing techniques based on CoM kinematics, integrating data of ground contacts and joint angles that allowed to separate propulsive from braking phases. This work constitutes the basis to extend the model from the laboratory to the field, providing a reliable measure of training and matches workload. Copyright © 2018 Elsevier Ltd. All rights reserved.

Detection of visually unrecognizable braking tracks using Laser-Induced Breakdown Spectroscopy, a feasibility study

NASA Astrophysics Data System (ADS)

Prochazka, David; Bilík, Martin; Prochazková, Petra; Brada, Michal; Klus, Jakub; Pořízka, Pavel; Novotný, Jan; Novotný, Karel; Ticová, Barbora; Bradáč, Albert; Semela, Marek; Kaiser, Jozef

2016-04-01

Identification of the position, length and mainly beginning of a braking track has proven to be essential for determination of causes of a road traffic accident. With the introduction of modern safety braking systems and assistance systems such as the Anti-lock Braking System (ABS) or Electronic Stability Control (ESC), the visual identification of braking tracks that has been used up until the present is proving to be rather complicated or even impossible. This paper focuses on identification of braking tracks using a spectrochemical analysis of the road surface. Laser-Induced Breakdown Spectroscopy (LIBS) was selected as a method suitable for fast in-situ element detection. In the course of detailed observations of braking tracks it was determined that they consist of small particles of tire treads that are caught in intrusions in the road surface. As regards detection of the "dust" resulting from wear and tear of tire treads in the environment, organic zinc was selected as the identification element in the past. The content of zinc in tire treads has been seen to differ with regard to various sources and tire types; however, the arithmetic mean and modus of these values are approximately 1% by weight. For in-situ measurements of actual braking tracks a mobile LIBS device equipped with a special module was used. Several measurements were performed for 3 different cars and tire types respectively which slowed down with full braking power. Moreover, the influence of different initial speed, vehicle mass and braking track length on detected signal is discussed here.

49 CFR 232.207 - Class IA brake tests-1,000-mile inspection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 4 2010-10-01 2010-10-01 false Class IA brake tests-1,000-mile inspection. 232... Class IA brake tests—1,000-mile inspection. (a) Except as provided in § 232.213, each train shall receive a Class IA brake test performed by a qualified person, as defined in § 232.5, at a location that...

49 CFR 232.207 - Class IA brake tests-1,000-mile inspection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 4 2011-10-01 2011-10-01 false Class IA brake tests-1,000-mile inspection. 232... Class IA brake tests—1,000-mile inspection. (a) Except as provided in § 232.213, each train shall receive a Class IA brake test performed by a qualified person, as defined in § 232.5, at a location that...

49 CFR 393.47 - Brake actuators, slack adjusters, linings/pads and drums/rotors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... of the rated strokes listed in SAE J1817—Long Stroke Air Brake Actuator Marking, July 2001 (See § 393... percent of the rated stroke marked on the brake chamber by the chamber manufacturer, or the readjustment... long stroke clamp type brake actuators must be less than 51 mm (2 inches) or 80 percent of the rated...

Correcting Students' Misconceptions about Automobile Braking Distances and Video Analysis Using Interactive Program Tracker

ERIC Educational Resources Information Center

Hockicko, Peter; Trpišová, Beáta; Ondruš, Ján

2014-01-01

The present paper informs about an analysis of students' conceptions about car braking distances and also presents one of the novel methods of learning: an interactive computer program Tracker that we used to analyse the process of braking of a car. The analysis of the students' conceptions about car braking distances consisted in…

49 CFR Appendix A to Part 232 - Schedule of Civil Penalties 1

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Failure to meet general design requirements 2,500 5,000 (d) Failure to have proper percentage of operative brakes from Class I brake test 5,000 7,500 (e) Operating with less than 85 percent operative brakes 5,000...) Failure to adopt and comply with periodic assessment plan 7,500 11,000 232.205Class I brake test—initial...

49 CFR Appendix A to Part 232 - Schedule of Civil Penalties 1

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Failure to meet general design requirements 2,500 5,000 (d) Failure to have proper percentage of operative brakes from Class I brake test 5,000 7,500 (e) Operating with less than 85 percent operative brakes 5,000...) Failure to adopt and comply with periodic assessment plan 7,500 11,000 232.205Class I brake test—initial...

49 CFR Appendix A to Part 232 - Schedule of Civil Penalties 1

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Failure to meet general design requirements 2,500 5,000 (d) Failure to have proper percentage of operative brakes from Class I brake test 5,000 7,500 (e) Operating with less than 85 percent operative brakes 5,000...) Failure to adopt and comply with periodic assessment plan 7,500 11,000 232.205Class I brake test—initial...

49 CFR Appendix A to Part 232 - Schedule of Civil Penalties 1

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Failure to meet general design requirements 2,500 5,000 (d) Failure to have proper percentage of operative brakes from Class I brake test 5,000 7,500 (e) Operating with less than 85 percent operative brakes 5,000...) Failure to adopt and comply with periodic assessment plan 7,500 11,000 232.205Class I brake test—initial...

Stopping a Roller Coaster Train

ERIC Educational Resources Information Center

Pendrill, Ann-Marie; Karlsteen, Magnus; Rodjegard, Henrik

2012-01-01

A roller coaster ride comes to an end. Magnets on the train induce eddy currents in the braking fins, giving a smooth rise in braking force as the remaining kinetic energy is absorbed by the brakes and converted to thermal energy. In this paper an IR camera was used to monitor the temperature of the first braking fin, before, during and after the…

Engineering report. Part 3: NASA lightweight wheel and brake sub-system. Lightweight brake development. [for application to space shuttle

NASA Technical Reports Server (NTRS)

Bok, L. D.

1973-01-01

The development of light weight wheel and brake systems designed to meet the space shuttle type requirements was investigated. The study includes the use of carbon graphite composite and beryllium as heat sink materials and the compatibility of these heat sink materials with the other structural components of the wheel and brake.

49 CFR 232.211 - Class III brake tests-trainline continuity inspection.

Code of Federal Regulations, 2012 CFR

2012-10-01

... pressure is being restored, the operator of the train shall know that the air brakes function as intended... determined that the brakes on the rear car of the train apply and release in response to air pressure changes... train that has previously received a Class I brake test and that has not been off air for more than four...

49 CFR 232.211 - Class III brake tests-trainline continuity inspection.

Code of Federal Regulations, 2011 CFR

2011-10-01

... pressure is being restored, the operator of the train shall know that the air brakes function as intended... determined that the brakes on the rear car of the train apply and release in response to air pressure changes... train that has previously received a Class I brake test and that has not been off air for more than four...

49 CFR 232.211 - Class III brake tests-trainline continuity inspection.

Code of Federal Regulations, 2010 CFR

2010-10-01

... pressure is being restored, the operator of the train shall know that the air brakes function as intended... determined that the brakes on the rear car of the train apply and release in response to air pressure changes... train that has previously received a Class I brake test and that has not been off air for more than four...

49 CFR 232.211 - Class III brake tests-trainline continuity inspection.

Code of Federal Regulations, 2013 CFR

2013-10-01

... pressure is being restored, the operator of the train shall know that the air brakes function as intended... determined that the brakes on the rear car of the train apply and release in response to air pressure changes... train that has previously received a Class I brake test and that has not been off air for more than four...

49 CFR 232.211 - Class III brake tests-trainline continuity inspection.

Code of Federal Regulations, 2014 CFR

2014-10-01

... pressure is being restored, the operator of the train shall know that the air brakes function as intended... determined that the brakes on the rear car of the train apply and release in response to air pressure changes... train that has previously received a Class I brake test and that has not been off air for more than four...

Impact of traffic intensity and pavement aggregate size on road dust particles loading

NASA Astrophysics Data System (ADS)

Amato, F.; Pandolfi, M.; Alastuey, A.; Lozano, A.; Contreras González, J.; Querol, X.

2013-10-01

Road dust emissions severely hamper PM10 urban air quality and their burden is expected to increase relatively to primary motor exhaust emissions. Beside the large influence of climate and meteorology, the emission potential varies widely also from one road to another due to numerous factors such as traffic conditions, pavement type and external sources. Nevertheless none of these factors is sufficiently known for a reliable description in emission modelling and for decision making in air quality management. In this study we carried out intensive road dust measurement campaigns in South Spain, with the aim of investigating the relationship between emission potential (i.e. road dust load) and traffic intensity, pavement aggregate size and distance from braking zones. Results indicate that, while no impact from braking activity can be drawn on the bulk road dust mass, an increase in traffic intensity or mean pavement aggregate size clearly reduce the single vehicle emission potential.

Design of the Electronic Brake Pressure Modulator Using a Direct Adaptive Fuzzy Controller in Commercial Vehicles for the Safety of Braking in Fail

NASA Astrophysics Data System (ADS)

Kim, Hunmo

In the brake systems, it is important to reduce the rear brake pressure in order to secure the safety of the vehicle in braking. So, there was some research that reduced and controlled the rear brake pressure exactly like a L. S. P. V and a E. L. S. P. V. However, the previous research has some weaknesses: the L. S. P. V is a mechanical system and its brake efficiency is lower than the efficiency of E. L. S. P. V. But, the cost of E. L. S. P. V is very higher so its application to the vehicle is very difficult. Additionally, when a fail appears in the circuit which controls the valves, the fail results in some wrong operation of the valves. But, the previous researchers didn't take the effect of fail into account. Hence, the efficiency of them is low and the safety of the vehicle is not confirmed. So, in this paper we develop a new economical pressure modulator that exactly controls brake pressure and confirms the safety of the vehicle in any case using a direct adaptive fuzzy controller.

Interactive design optimization of magnetorheological-brake actuators using the Taguchi method

NASA Astrophysics Data System (ADS)

Erol, Ozan; Gurocak, Hakan

2011-10-01

This research explored an optimization method that would automate the process of designing a magnetorheological (MR)-brake but still keep the designer in the loop. MR-brakes apply resistive torque by increasing the viscosity of an MR fluid inside the brake. This electronically controllable brake can provide a very large torque-to-volume ratio, which is very desirable for an actuator. However, the design process is quite complex and time consuming due to many parameters. In this paper, we adapted the popular Taguchi method, widely used in manufacturing, to the problem of designing a complex MR-brake. Unlike other existing methods, this approach can automatically identify the dominant parameters of the design, which reduces the search space and the time it takes to find the best possible design. While automating the search for a solution, it also lets the designer see the dominant parameters and make choices to investigate only their interactions with the design output. The new method was applied for re-designing MR-brakes. It reduced the design time from a week or two down to a few minutes. Also, usability experiments indicated significantly better brake designs by novice users.

Friction and Braking Application of Unhazardous Palm Slag Brake Pad Composite

NASA Astrophysics Data System (ADS)

Khoni, Norizzahthul Ainaa Abdul; Ruzaidi Ghazali, Che Mohd; Bakri Abdullah, Mohd Mustafa Al

2018-03-01

This paper reveals new alternative friction materials for brake pads. Palm slag was studied as new friction materials in brake pads but its much harder made it difficult to be applied. As a way to reduce the hardness, tire dust was including as purpose on stabilizing the hardness of brake pads. The palm slag was sieves to get desired size that is 150 μm, 300 μm and 600 μm. The percentage weight of materials used are 20% graphite, 20% aluminium oxide, 20% steel fiber, 20% polyester resin and another 40% are varied between tire dust and palm slag. All of materials were blend and compress by using hot pressed machine. The composites properties that were examined are density, porosity, hardness, compressive strength, microstructure analysis and wear rate. The composition of 30% palm slag, 10% tire dust and larger size of filler give better result of mechanical properties and less wear rate of brake pads composites. Then, palm slag can be used in producing of non asbestos brake pads.

Design Considerations and Experimental Verification of a Rail Brake Armature Based on Linear Induction Motor Technology

NASA Astrophysics Data System (ADS)

Sakamoto, Yasuaki; Kashiwagi, Takayuki; Hasegawa, Hitoshi; Sasakawa, Takashi; Fujii, Nobuo

This paper describes the design considerations and experimental verification of an LIM rail brake armature. In order to generate power and maximize the braking force density despite the limited area between the armature and the rail and the limited space available for installation, we studied a design method that is suitable for designing an LIM rail brake armature; we considered adoption of a ring winding structure. To examine the validity of the proposed design method, we developed a prototype ring winding armature for the rail brakes and examined its electromagnetic characteristics in a dynamic test system with roller rigs. By repeating various tests, we confirmed that unnecessary magnetic field components, which were expected to be present under high speed running condition or when a ring winding armature was used, were not present. Further, the necessary magnetic field component and braking force attained the desired values. These studies have helped us to develop a basic design method that is suitable for designing the LIM rail brake armatures.

Braking and cornering studies on an air cushion landing system

NASA Technical Reports Server (NTRS)

Daugherty, R. H.

1983-01-01

An experimental investigation was conducted to evaluate several concepts for braking and steering a vehicle equipped with an air cushion landing system (ACLS). The investigation made use of a modified airboat equipped with an ACLS. Braking concepts were characterized by the average deceleration of the vehicle. Reduced lobe flow and cavity venting braking concepts were evaluated in this program. The cavity venting braking concept demonstrated the best performance, producing decelerations on the test vehicle on the same order as moderate braking with conventional wheel brakes. Steering concepts were evaluated by recording the path taken while attempting to follow a prescribed maneuver. The steering concepts evaluated included using rudders only, using differential lobe flow, and using rudders combined with a lightly loaded, nonsteering center wheel. The latter concept proved to be the most accurate means of steering the vehicle on the ACLS, producing translational deviations two to three times higher than those from conventional nose-gear steering. However, this concept was still felt to provide reasonably precise steering control for the ACLS-equipped vehicle.

Consideration of Materials for Aircraft Brakes

NASA Technical Reports Server (NTRS)

Peterson, M. B.; Ho, T.

1972-01-01

An exploratory investigation was conducted concerning materials and their properties for use in aircraft brakes. Primary consideration was given to the heat dissipation and the frictional behavior of materials. Used brake pads and rotors were analyzed as part of the investigation. A simple analysis was conducted in order to determine the most significant factors which affect surface temperatures. It was found that where size and weight restrictions are necessary, the specific heat of the material, and maintaining uniform contact area are the most important factors. A criterion was suggested for optimum sizing of the brake disks. Bench friction tests were run with brake materials. It was found that there is considerable friction variation due to the formation and removal of surface oxide films. Other causes of friction variations are surface softening and melting. The friction behavior at high temperature was found to be more characteristic of the steel surface rather than the copper brake material. It is concluded that improved brake materials are feasible.

Design of permanent magnet eddy current brake for a small scaled electromagnetic launch model

NASA Astrophysics Data System (ADS)

Zhou, Shigui; Yu, Haitao; Hu, Minqiang; Huang, Lei

2012-04-01

A variable pole-pitch double-sided permanent magnet (PM) linear eddy current brake (LECB) is proposed for a small scaled electromagnetic launch model. A two-dimensional (2D) analytical steady state model is presented for the double-sided PM-LECB, and the expression for the braking force is derived. Based on the analytical model, the material and eddy current skin effect of the conducting plate are analyzed. Moreover, a variable pole-pitch double-sided PM-LECB is proposed for the effective braking of the moving plate. In addition, the braking force is predicted by finite element (FE) analysis, and the simulated results are in good agreement with the analytical model. Finally, a prototype is presented to test the braking profile for validation of the proposed design.

Aerodynamic braking of high speed ground transportation vehicles.

NASA Technical Reports Server (NTRS)

Marte, J. E.; Marko, W. J.

1973-01-01

The drag effectiveness of aerodynamic brakes arranged in series on a train-like vehicle was investigated. Fixed- and moving-model testing techniques were used in order to determine the importance of proper vehicle-ground interference simulation. Fixed-model tests were carried out on a sting-mounted model: alone; with a fixed ground plane; and in proximity to an image model. Moving-model tests were conducted in a vertical slide-wire facility with and without a ground plane. Results from investigations of one brake configuration are presented which show the effect of the number of brakes in the set and of spacing between brakes.

Use of MSC/NASTRAN for the thermal analysis of the Space Shuttle Orbiter braking system

NASA Technical Reports Server (NTRS)

Shu, James; Mccann, David

1987-01-01

A description is given of the thermal modeling and analysis effort being conducted to investigate the transient temperature and thermal stress characteristics of the Space Shuttle Orbiter brake components and subsystems. Models are constructed of the brake stator as well as of the entire brake assembly to analyze the temperature distribution and thermal stress during the landing and braking process. These investigations are carried out on a UNIVAC computer system with MSC/NASTRAN Version 63. Analytical results and solution methods are presented and comparisons are made with SINDA results.

Trace element carriers in combined sewer during dry and wet weather: an electron microscope investigation.

PubMed

El Samrani, A G; Lartiges, B S; Ghanbaja, J; Yvon, J; Kohler, A

2004-04-01

The nature of trace element carriers contained in sewage and combined sewer overflow (CSO) was investigated by TEM-EDX-Electron diffraction and SEM-EDX. During dry weather, chalcophile elements were found to accumulate in sewer sediments as early diagenetic sulfide phases. The sulfurization of some metal alloys was also evidenced. Other heavy metal carriers detected in sewage include metal alloys, some iron oxihydroxide phases and neoformed phosphate minerals such as anapaite. During rain events, the detailed characterization of individual mineral species allowed to differentiate the contributions from various specific sources. Metal plating particles, barite from automobile brake, or rare earth oxides from catalytic exhaust pipes, originate from road runoff, whereas PbSn alloys and lead carbonates are attributed to zinc-works from roofs and paint from building siding. Soil contribution can be traced by the presence of clay minerals, iron oxihydroxides, zircons and rare earth phosphates. However, the most abundant heavy metal carriers in CSO samples were the sulfide particles eroded from sewer sediments. The evolution of relative abundances of trace element carriers during a single storm event, suggests that the pollution due to the "first flush" effect principally results from the sewer stock of sulfides and previously deposited metal alloys, rather than from urban surface runoff.

Dry powder mixes comprising phase change materials

DOEpatents

Salyer, Ival O.

1994-01-01

A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft.

Dry powder mixes comprising phase change materials

DOEpatents

Salyer, Ival O.

1995-01-01

A free flowing, conformable powder-like mix of silica particles and a phase change material (PCM) is provided. The silica particles have a critical size of about 0.005 to about 0.025 microns and the PCM must be added to the silica in an amount of 75% or less PCM per combined weight of silica and PCM. The powder-like mix can be used in tableware items, medical wraps, tree wraps, garments, quilts and blankets, and particularly in applications for heat protection for heat sensitive items, such as aircraft flight recorders, and for preventing brake fade in automobiles, buses, trucks and aircraft.

Antiskid braking system

NASA Technical Reports Server (NTRS)

Pazdera, J. S.

1974-01-01

Published report describes analytical development and simulation of braking system. System prevents wheels from skidding when brakes are applied, significantly reducing stopping distance. Report also presents computer simulation study on system as applied to aircraft.

Quantitative Analysis of a Hybrid Electric HMMWV for Fuel Economy Improvement

DTIC Science & Technology

2012-05-01

HMMWV of equivalent size. Hybrid vehicle powertrains show improved fuel economy gains due to optimized engine operation and regenerative braking . In... regenerative braking . Validated vehicle models as well as data collected on test tracks are used in the quantitative analysis. The regenerative braking ...hybrid electric vehicle, drive cycle, fuel economy, engine efficiency, regenerative braking . 1 Introduction The US Army (Tank Automotive

Electronic Stability Control

DTIC Science & Technology

2013-12-05

pressure (see Section 2.3) - Optional 1 percent Tire pressure 0.7 kilopascals (kPa) (0.1 pounds per square inch (psi)) Brake pedal application...d. Load cell to monitor brake pedal force with a range of 0 to 136 kg (0 to 300 lb) and accuracy + 1.0 percent full scale. While brake pedal ...sideslip, brake pedal application force and document the manufacturer, identification (serial number, part number, etc.), calibration information

49 CFR 232.217 - Train brake tests conducted using yard air.

Code of Federal Regulations, 2013 CFR

2013-10-01

... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage or...

49 CFR 232.217 - Train brake tests conducted using yard air.

Code of Federal Regulations, 2014 CFR

2014-10-01

... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage or...

49 CFR 232.217 - Train brake tests conducted using yard air.

Code of Federal Regulations, 2012 CFR

2012-10-01

... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage or...

49 CFR 232.217 - Train brake tests conducted using yard air.

Code of Federal Regulations, 2011 CFR

2011-10-01

... reduction of brake pipe air pressure at the same, or slower, rate as an engineer's brake valve. (b) The yard... (f). (2) At a minimum, yard air pressure shall be 60 psi at the end of the consist or block of cars... device. (3) If the air pressure of the yard test device is less than 80 psi, then a brake pipe leakage or...

49 CFR 231.1 - Box and other house cars built or placed in service before October 1, 1966.

Code of Federal Regulations, 2013 CFR

2013-10-01

... and passing through the inside face of knuckle when closed with coupler horn against the buffer block... brake-shaft step which will permit the brake chain to drop under the brake shaft shall not be used. U...-eighths of an inch square. Square-fit taper, nominally 2 in 12 inches. (See plate A.) (vi) Brake chain...

49 CFR 231.1 - Box and other house cars built or placed in service before October 1, 1966.

Code of Federal Regulations, 2010 CFR

2010-10-01

... and passing through the inside face of knuckle when closed with coupler horn against the buffer block... brake-shaft step which will permit the brake chain to drop under the brake shaft shall not be used. U...-eighths of an inch square. Square-fit taper, nominally 2 in 12 inches. (See plate A.) (vi) Brake chain...

49 CFR 231.1 - Box and other house cars built or placed in service before October 1, 1966.

Code of Federal Regulations, 2011 CFR

2011-10-01

... and passing through the inside face of knuckle when closed with coupler horn against the buffer block... brake-shaft step which will permit the brake chain to drop under the brake shaft shall not be used. U...-eighths of an inch square. Square-fit taper, nominally 2 in 12 inches. (See plate A.) (vi) Brake chain...

49 CFR 231.1 - Box and other house cars built or placed in service before October 1, 1966.

Code of Federal Regulations, 2012 CFR

2012-10-01

... and passing through the inside face of knuckle when closed with coupler horn against the buffer block... brake-shaft step which will permit the brake chain to drop under the brake shaft shall not be used. U...-eighths of an inch square. Square-fit taper, nominally 2 in 12 inches. (See plate A.) (vi) Brake chain...

49 CFR 231.1 - Box and other house cars built or placed in service before October 1, 1966.

Code of Federal Regulations, 2014 CFR

2014-10-01

... and passing through the inside face of knuckle when closed with coupler horn against the buffer block... brake-shaft step which will permit the brake chain to drop under the brake shaft shall not be used. U...-eighths of an inch square. Square-fit taper, nominally 2 in 12 inches. (See plate A.) (vi) Brake chain...

Multivariate research in areas of phosphorus cast-iron brake shoes manufacturing using the statistical analysis and the multiple regression equations

NASA Astrophysics Data System (ADS)

Kiss, I.; Cioată, V. G.; Alexa, V.; Raţiu, S. A.

2017-05-01

The braking system is one of the most important and complex subsystems of railway vehicles, especially when it comes for safety. Therefore, installing efficient safe brakes on the modern railway vehicles is essential. Nowadays is devoted attention to solving problems connected with using high performance brake materials and its impact on thermal and mechanical loading of railway wheels. The main factor that influences the selection of a friction material for railway applications is the performance criterion, due to the interaction between the brake block and the wheel produce complex thermos-mechanical phenomena. In this work, the investigated subjects are the cast-iron brake shoes, which are still widely used on freight wagons. Therefore, the cast-iron brake shoes - with lamellar graphite and with a high content of phosphorus (0.8-1.1%) - need a special investigation. In order to establish the optimal condition for the cast-iron brake shoes we proposed a mathematical modelling study by using the statistical analysis and multiple regression equations. Multivariate research is important in areas of cast-iron brake shoes manufacturing, because many variables interact with each other simultaneously. Multivariate visualization comes to the fore when researchers have difficulties in comprehending many dimensions at one time. Technological data (hardness and chemical composition) obtained from cast-iron brake shoes were used for this purpose. In order to settle the multiple correlation between the hardness of the cast-iron brake shoes, and the chemical compositions elements several model of regression equation types has been proposed. Because a three-dimensional surface with variables on three axes is a common way to illustrate multivariate data, in which the maximum and minimum values are easily highlighted, we plotted graphical representation of the regression equations in order to explain interaction of the variables and locate the optimal level of each variable for maximal response. For the calculation of the regression coefficients, dispersion and correlation coefficients, the software Matlab was used.

Magnetostrictive Brake

NASA Technical Reports Server (NTRS)

Diftler, Myron A.; Hulse, Aaron

2010-01-01

A magnetostrictive brake has been designed as a more energy-efficient alternative to a magnetic fail-safe brake in a robot. (In the specific application, failsafe signifies that the brake is normally engaged; that is, power must be supplied to allow free rotation.) The magnetic failsafe brake must be supplied with about 8 W of electric power to initiate and maintain disengagement. In contrast, the magnetostrictive brake, which would have about the same dimensions and the same torque rating as those of the magnetic fail-safe brake, would demand only about 2 W of power for disengagement. The brake (see figure) would include a stationary base plate and a hub mounted on the base plate. Two solenoid assemblies would be mounted in diametrically opposed recesses in the hub. The cores of the solenoids would be made of the magnetostrictive alloy Terfenol-D or equivalent. The rotating part of the brake would be a ring-and spring- disk subassembly. By means of leaf springs not shown in the figure, this subassembly would be coupled with the shaft that the brake is meant to restrain. With no power supplied to the solenoids, a permanent magnet would pull axially on a stepped disk and on a shelf in the hub, causing the ring to be squeezed axially between the stepped disk and the hub. The friction associated with this axial squeeze would effect the braking action. Supplying electric power to the solenoids would cause the magnetostrictive cylinders to push radially inward against a set of wedges that would be in axial contact with the stepped disk. The wedges would convert the radial magnetostrictive strain to a multiplied axial displacement of the stepped disk. This axial displacement would be just large enough to lift the stepped disk, against the permanent magnetic force, out of contact with the ring. The ring would then be free to turn because it would no longer be squeezed axially between the stepped disk and the hub.

Influence of centrifuge brake on residual platelet count and routine coagulation tests in citrated plasma.

PubMed

Daves, Massimo; Giacomuzzi, Katia; Tagnin, Enrico; Jani, Erika; Adcock Funk, Dorothy M; Favaloro, Emmanuel J; Lippi, Giuseppe

2014-04-01

Sample centrifugation is an essential step in the coagulation laboratory, as clotting tests are typically performed on citrated platelet (PLT) poor plasma (PPP). Nevertheless, no clear indication has been provided as to whether centrifugation of specimens should be performed with the centrifuge brake set to on or off. Fifty consecutive sodium citrate anticoagulated samples were collected and divided into two aliquots. The former was centrifuged as for Clinical Laboratory Standards Institute (CLSI) guidelines with the centrifuge brake set to on, whereas the latter was centrifuged again as for CLSI guidelines, but with the brake set to off. In the PPP of all samples, a PLT count was performed, followed by the analysis of activated partial thromboplastin time (APTT), prothrombin time (PT) and fibrinogen (FBG). The PLT count after samples centrifugation was substantially reduced, either with centrifuge brake set to on or off (5 ± 1 versus 3 ± 1 × 10/l; P = 0.009). The frequency of samples exceeding a PLT count less than 10 × 10/l was nearly double in samples centrifuged with the brake on than in those with the brake off (14 versus 8%; P < 0.01). Although no significant difference was found for APTT values, PT was slightly prolonged using the centrifuge brake set to on (mean bias 0.2 s; P < 0.001). FBG values were also significantly higher using the centrifuge brake set to on (mean bias 0.29 g/l; P < 0.001). The results of this study indicate that sample centrifugation for routine coagulation testing should be preferably performed with the centrifuge brake set to off for providing a better quality specimen.

Potential Occupant Injury Reduction in Pre-Crash System Equipped Vehicles in the Striking Vehicle of Rear-end Crashes.

PubMed

Kusano, Kristofer D; Gabler, Hampton C

2010-01-01

To mitigate the severity of rear-end and other collisions, Pre-Crash Systems (PCS) are being developed. These active safety systems utilize radar and/or video cameras to determine when a frontal crash, such as a front-to-back rear-end collisions, is imminent and can brake autonomously, even with no driver input. Of these PCS features, the effects of autonomous pre-crash braking are estimated. To estimate the maximum potential for injury reduction due to autonomous pre-crash braking in the striking vehicle of rear-end crashes, a methodology is presented for determining 1) the reduction in vehicle crash change in velocity (ΔV) due to PCS braking and 2) the number of injuries that could be prevented due to the reduction in collision severity. Injury reduction was only performed for belted drivers, as unbelted drivers have an unknown risk of being thrown out of position. The study was based on 1,406 rear-end striking vehicles from NASS / CDS years 1993 to 2008. PCS parameters were selected from realistic values and varied to examine the effect on system performance. PCS braking authority was varied from 0.5 G's to 0.8 G's while time to collision (TTC) was held at 0.45 seconds. TTC was then varied from 0.3 second to 0.6 seconds while braking authority was held constant at 0.6 G's. A constant braking pulse (step function) and ramp-up braking pulse were used. The study found that automated PCS braking could reduce the crash ΔV in rear-end striking vehicles by an average of 12% - 50% and avoid 0% - 14% of collisions, depending on PCS parameters. Autonomous PCS braking could potentially reduce the number of injured drivers who are belted by 19% to 57%.

Ground reaction forces and knee kinetics during single and repeated badminton lunges.

PubMed

Lam, Wing Kai; Ding, Rui; Qu, Yi

2017-03-01

Repeated movement (RM) lunge that frequently executed in badminton might be used for footwear evaluation. This study examined the influence of single movement (SM) and RM lunges on the ground reaction forces (GRFs) and knee kinetics during the braking phase of a badminton lunge step. Thirteen male university badminton players performed left-forward lunges in both SM and RM sessions. Force platform and motion capturing system were used to measure GRFs and knee kinetics variables. Paired t-test was performed to determine any significant differences between SM and RM lunges regarding mean and coefficient of variation (CV) in each variable. The kinetics results indicated that compared to SM lunges, the RM lunges had shorter contact time and generated smaller maximum loading rate of impact force, peak knee anterior-posterior force, and peak knee sagittal moment but generated larger peak horizontal resultant forces (Ps < 0.05). Additionally, the RM lunges had lower CV for peak knee medial-lateral and vertical forces (Ps < 0.05). These results suggested that the RM testing protocols had a distinct loading response and adaptation pattern during lunge and that the RM protocol showed higher within-trial reliability, which may be beneficial for the knee joint loading evaluation under different interventions.

Brake testing methodology study : driver effects testing

DOT National Transportation Integrated Search

1999-03-01

The National Highway Traffic Safety Administration (NHTSA) is exploring the feasibility of developing brake tests to measure brake system performance of light vehicles. Developing test procedures requires controlling test variability so that measured...

Electromechanical imitator of antilock braking modes of wheels with pneumatic tire and its application for the runways friction coefficient measurement

NASA Astrophysics Data System (ADS)

Putov, A. V.; Kopichev, M. M.; Ignatiev, K. V.; Putov, V. V.; Stotckaia, A. D.

2017-01-01

In this paper it is considered a discussion of the technique that realizes a brand new method of runway friction coefficient measurement based upon the proposed principle of measuring wheel braking control for the imitation of antilock braking modes that are close to the real braking modes of the aircraft chassis while landing that are realized by the aircraft anti-skid systems. Also here is the description of the model of towed measuring device that realizes a new technique of runway friction coefficient measuring, based upon the measuring wheel braking control principle. For increasing the repeatability accuracy of electromechanical braking imitation system the sideslip (brake) adaptive control system is proposed. Based upon the Burkhard model and additive random processes several mathematical models were created that describes the friction coefficient arrangement along the airstrip with different qualitative adjectives. Computer models of friction coefficient measuring were designed and first in the world the research of correlation between the friction coefficient measuring results and shape variations, intensity and cycle frequency of the measuring wheel antilock braking modes. The sketch engineering documentation was designed and prototype of the latest generation measuring device is ready to use. The measuring device was tested on the autonomous electromechanical examination laboratory treadmill bench. The experiments approved effectiveness of method of imitation the antilock braking modes for solving the problem of correlation of the runway friction coefficient measuring.

Investigations into the Properties, Conditions, and Effects of the Ionosphere.

DTIC Science & Technology

1988-01-15

Innovative Approaches to Direct Measurement of N e 28 ]- J FEASIBILITY OF RADIO BLACKOUT MITIGATION IN THE BRAKING PHASE 28 OF AOTV OPERATIONS 1. Brief...Cell could be tested under simulated flight conditions in the SAIC plasma laboratory facility. AJ. FEASIBILITY OF RADIO BLACKOUT MITIGATION IN THE...enable calculation of chemical modification techniques ,. on phenomena of radio blackout during re-entry of orbiting spacecraft . * ,1. Brief

Baseline tests of the AM General DJ-5E electruck electric delivery van

NASA Technical Reports Server (NTRS)

Dustin, M. O.; Tryon, H. B.; Sargent, N. B.

1977-01-01

An electric quarter ton truck designed for use as a postal delivery vehicle was tested to characterize the state of the art of electric vehicles. Vehicle performance test results are presented. It is powered by a single-module, 54 volt industrial battery through a silicon controlled rectifier continuously adjustable controller with regenerative braking applied to a direct current compound wound motor.

49 CFR Appendix B to Part 232 - Part 232 Prior to May 31, 2001 as Clarified Effective April 10, 2002

Code of Federal Regulations, 2013 CFR

2013-10-01

... and passenger train car brakes. 232.19End of train device. Appendix A to Part 232 Appendix B to Part... power or train brakes, not less than 85 percent of the cars of such train shall have their brakes used and operated by the engineer of the locomotive drawing such train, and all power-brake cars in every...

49 CFR Appendix B to Part 232 - Part 232 Prior to May 31, 2001 as Clarified Effective April 10, 2002

Code of Federal Regulations, 2014 CFR

2014-10-01

... and passenger train car brakes. 232.19End of train device. Appendix A to Part 232 Appendix B to Part... power or train brakes, not less than 85 percent of the cars of such train shall have their brakes used and operated by the engineer of the locomotive drawing such train, and all power-brake cars in every...

49 CFR Appendix B to Part 232 - Part 232 Prior to May 31, 2001 as Clarified Effective April 10, 2002

Code of Federal Regulations, 2012 CFR

2012-10-01

... and passenger train car brakes. 232.19End of train device. Appendix A to Part 232 Appendix B to Part... power or train brakes, not less than 85 percent of the cars of such train shall have their brakes used and operated by the engineer of the locomotive drawing such train, and all power-brake cars in every...

A unique concept for automatically controlling the braking action of wheeled vehicles during minimum distance stops

NASA Technical Reports Server (NTRS)

Barthlome, D. E.

1975-01-01

Test results of a unique automatic brake control system are outlined and a comparison is made of its mode of operation to that of an existing skid control system. The purpose of the test system is to provide automatic control of braking action such that hydraulic brake pressure is maintained at a near constant, optimum value during minimum distance stops.

Performance of a Rotary Wing Air Brake in Supersonic Flow

DTIC Science & Technology

1947-05-18

a pneumatic thrust measuring system (3) Strobotac and Audio Signal Generator for RPM measurements, (4) motion picture cameras and miscellaneous...produced by the head to keep the brake engaged. The " pneumatic thrust measuring system1* utilised the bellows described above to oppose the drag force...a brake , to prevent its rotation when desired. To release the brake it was necessary to inflate the internal thrust bellows, thereby disengaging

Operator’s Manual. Prototype Heavy Rescue/Fire Fighting Vehicle

DTIC Science & Technology

1980-09-01

system for emergency operation if pressure is lost in either parking or service brake systems . The system is operational automatically and is...controlled by the foot treadle ’sive. It will provide for TWO full brake applications and ONE release. ELECTRICAL SYSTEM A dual battery system is utilized for...cleaner. * Lubricate chassis. . Repack wheel bearings. . Inspect brake system and adjust brakes . . Replace fuel filter. . Check high and low idle.

Research on transient thermal process of a friction brake during repetitive cycles of operation

NASA Astrophysics Data System (ADS)

Slavchev, Yanko; Dimitrov, Lubomir; Dimitrov, Yavor

2017-12-01

Simplified models are used in the classical engineering analyses of the friction brake heating temperature during repetitive cycles of operation to determine basically the maximum and minimum brake temperatures. The objective of the present work is to broaden and complement the possibilities for research through a model that is based on the classical scheme of the Newton's law of cooling and improves the studies by adding a disturbance function for a corresponding braking process. A general case of braking in non-periodic repetitive mode is considered, for which a piecewise function is defined to apply pulse thermal loads to the system. Cases with rectangular and triangular waveforms are presented. Periodic repetitive braking process is also studied using a periodic rectangular waveform until a steady thermal state is achieved. Different numerical methods such as the Euler's method, the classical fourth order Runge-Kutta (RK4) and the Runge-Kutta-Fehlberg 4-5 (RKF45) are used to solve the non-linear differential equation of the model. The constructed model allows during pre-engineering calculations to be determined effectively the time for reaching the steady thermal state of the brake, to be simulated actual braking modes in vehicles and material handling machines, and to be accounted for the thermal impact when performing fatigue calculations.

KSC-04PD-1088

NASA Technical Reports Server (NTRS)

2004-01-01

KENNEDY SPACE CENTER, FLA. -- A Rudder Speed Brake Actuator is being removed from the orbiter Atlantis for shipment to the vendor for inspection. An actuator is a motor that moves the tail rudder back and forth to help steer it during landing and brake its speed. The vertical tail consists of a structural fin surface made of aluminum, the Rudder Speed Brake surface, a tip and a lower trailing edge. The rudder splits into two halves to serve as a speed brake. The vertical tail and Rudder Speed Brake are covered with a reusable thermal protection system. Atlantis is undergoing maintenance and inspection in the Orbiter Processing Facility for a future mission.