A Pneumatic Tactile Sensor for Co-Operative Robots

PubMed Central

He, Rui; Yu, Jianjun; Zuo, Guoyu

2017-01-01

Tactile sensors of comprehensive functions are urgently needed for the advanced robot to co-exist and co-operate with human beings. Pneumatic tactile sensors based on air bladder possess some noticeable advantages for human-robot interaction application. In this paper, we construct a pneumatic tactile sensor and apply it on the fingertip of robot hand to realize the sensing of force, vibration and slippage via the change of the pressure of the air bladder, and we utilize the sensor to perceive the object’s features such as softness and roughness. The pneumatic tactile sensor has good linearity, repeatability and low hysteresis and both its size and sensing range can be customized by using different material as well as different thicknesses of the air bladder. It is also simple and cheap to fabricate. Therefore, the pneumatic tactile sensor is suitable for the application of co-operative robots and can be widely utilized to improve the performance of service robots. We can apply it to the fingertip of the robot to endow the robotic hand with the ability to co-operate with humans and handle the fragile objects because of the inherent compliance of the air bladder. PMID:29125565

Tactile Evaluation Feedback System for Multi-Layered Structure Inspired by Human Tactile Perception Mechanism.

PubMed

Hashim, Iza Husna Mohamad; Kumamoto, Shogo; Takemura, Kenjiro; Maeno, Takashi; Okuda, Shin; Mori, Yukio

2017-11-11

Tactile sensation is one type of valuable feedback in evaluating a product. Conventionally, sensory evaluation is used to get direct subjective responses from the consumers, in order to improve the product's quality. However, this method is a time-consuming and costly process. Therefore, this paper proposes a novel tactile evaluation system that can give tactile feedback from a sensor's output. The main concept of this system is hierarchically layering the tactile sensation, which is inspired by the flow of human perception. The tactile sensation is classified from low-order of tactile sensation (LTS) to high-order of tactile sensation (HTS), and also to preference. Here, LTS will be correlated with physical measures. Furthermore, the physical measures that are used to correlate with LTS are selected based on four main aspects of haptic information (roughness, compliance, coldness, and slipperiness), which are perceived through human tactile sensors. By using statistical analysis, the correlation between each hierarchy was obtained, and the preference was derived in terms of physical measures. A verification test was conducted by using unknown samples to determine the reliability of the system. The results showed that the system developed was capable of estimating preference with an accuracy of approximately 80%.

3D capacitive tactile sensor using DRIE micromachining

NASA Astrophysics Data System (ADS)

Chuang, Chiehtang; Chen, Rongshun

2005-07-01

This paper presents a three dimensional micro capacitive tactile sensor that can detect normal and shear forces which is fabricated using deep reactive ion etching (DRIE) bulk silicon micromachining. The tactile sensor consists of a force transmission plate, a symmetric suspension system, and comb electrodes. The sensing character is based on the changes of capacitance between coplanar sense electrodes. High sensitivity is achieved by using the high aspect ratio interdigital electrodes with narrow comb gaps and large overlap areas. The symmetric suspension mechanism of this sensor can easily solve the coupling problem of measurement and increase the stability of the structure. In this paper, the sensor structure is designed, the capacitance variation of the proposed device is theoretically analyzed, and the finite element analysis of mechanical behavior of the structures is performed.

Review of Recent Inkjet-Printed Capacitive Tactile Sensors

PubMed Central

Salim, Ahmed

2017-01-01

Inkjet printing is an advanced printing technology that has been used to develop conducting layers, interconnects and other features on a variety of substrates. It is an additive manufacturing process that offers cost-effective, lightweight designs and simplifies the fabrication process with little effort. There is hardly sufficient research on tactile sensors and inkjet printing. Advancements in materials science and inkjet printing greatly facilitate the realization of sophisticated tactile sensors. Starting from the concept of capacitive sensing, a brief comparison of printing techniques, the essential requirements of inkjet-printing and the attractive features of state-of-the art inkjet-printed tactile sensors developed on diverse substrates (paper, polymer, glass and textile) are presented in this comprehensive review. Recent trends in inkjet-printed wearable/flexible and foldable tactile sensors are evaluated, paving the way for future research. PMID:29125584

Development of a biomimetic roughness sensor for tactile information with an elastomer

NASA Astrophysics Data System (ADS)

Choi, Jae-Young; Kim, Sung Joon; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, Ja Choon

2016-04-01

Human uses various sensational information for identifying an object. When contacting an unidentified object with no vision, tactile sensation provides a variety of information to perceive. Tactile sensation plays an important role to recognize a shape of surfaces from touching. In robotic fields, tactile sensation is especially meaningful. Robots can perform more accurate job using comprehensive tactile information. And in case of using sensors made by soft material like silicone, sensors can be used in various situations. So we are developing a tactile sensor with soft materials. As the conventional robot operates in a controlled environment, it is a good model to make robots more available at any circumstance that sensory systems of living things. For example, there are lots of mechanoreceptors that each of them has different roles detecting simulation in side of human skin tissue. By mimicking the mechanoreceptor, a sensory system can be realized more closely to human being. It is known that human obtains roughness information through scanning the surface with fingertips. During that times, subcutaneous mechanoreceptors detect vibration. In the same way, while a robot is scanning a surface of object, a roughness sensor developed detects vibrations generated between contacting two surfaces. In this research, a roughness sensor made by an elastomer was developed and experiment for perception of objects was conducted. We describe means to compare the roughness of objects with a newly developed sensor.

Scalable fabric tactile sensor arrays for soft bodies

NASA Astrophysics Data System (ADS)

Day, Nathan; Penaloza, Jimmy; Santos, Veronica J.; Killpack, Marc D.

2018-06-01

Soft robots have the potential to transform the way robots interact with their environment. This is due to their low inertia and inherent ability to more safely interact with the world without damaging themselves or the people around them. However, existing sensing for soft robots has at least partially limited their ability to control interactions with their environment. Tactile sensors could enable soft robots to sense interaction, but most tactile sensors are made from rigid substrates and are not well suited to applications for soft robots which can deform. In addition, the benefit of being able to cheaply manufacture soft robots may be lost if the tactile sensors that cover them are expensive and their resolution does not scale well for manufacturability. This paper discusses the development of a method to make affordable, high-resolution, tactile sensor arrays (manufactured in rows and columns) that can be used for sensorizing soft robots and other soft bodies. However, the construction results in a sensor array that exhibits significant amounts of cross-talk when two taxels in the same row are compressed. Using the same fabric-based tactile sensor array construction design, two different methods for cross-talk compensation are presented. The first uses a mathematical model to calculate a change in resistance of each taxel directly. The second method introduces additional simple circuit components that enable us to isolate each taxel electrically and relate voltage to force directly. Fabric sensor arrays are demonstrated for two different soft-bodied applications: an inflatable single link robot and a human wrist.

Design Methodology for Magnetic Field-Based Soft Tri-Axis Tactile Sensors.

PubMed

Wang, Hongbo; de Boer, Greg; Kow, Junwai; Alazmani, Ali; Ghajari, Mazdak; Hewson, Robert; Culmer, Peter

2016-08-24

Tactile sensors are essential if robots are to safely interact with the external world and to dexterously manipulate objects. Current tactile sensors have limitations restricting their use, notably being too fragile or having limited performance. Magnetic field-based soft tactile sensors offer a potential improvement, being durable, low cost, accurate and high bandwidth, but they are relatively undeveloped because of the complexities involved in design and calibration. This paper presents a general design methodology for magnetic field-based three-axis soft tactile sensors, enabling researchers to easily develop specific tactile sensors for a variety of applications. All aspects (design, fabrication, calibration and evaluation) of the development of tri-axis soft tactile sensors are presented and discussed. A moving least square approach is used to decouple and convert the magnetic field signal to force output to eliminate non-linearity and cross-talk effects. A case study of a tactile sensor prototype, MagOne, was developed. This achieved a resolution of 1.42 mN in normal force measurement (0.71 mN in shear force), good output repeatability and has a maximum hysteresis error of 3.4%. These results outperform comparable sensors reported previously, highlighting the efficacy of our methodology for sensor design.

Design Methodology for Magnetic Field-Based Soft Tri-Axis Tactile Sensors

PubMed Central

Wang, Hongbo; de Boer, Greg; Kow, Junwai; Alazmani, Ali; Ghajari, Mazdak; Hewson, Robert; Culmer, Peter

2016-01-01

Tactile sensors are essential if robots are to safely interact with the external world and to dexterously manipulate objects. Current tactile sensors have limitations restricting their use, notably being too fragile or having limited performance. Magnetic field-based soft tactile sensors offer a potential improvement, being durable, low cost, accurate and high bandwidth, but they are relatively undeveloped because of the complexities involved in design and calibration. This paper presents a general design methodology for magnetic field-based three-axis soft tactile sensors, enabling researchers to easily develop specific tactile sensors for a variety of applications. All aspects (design, fabrication, calibration and evaluation) of the development of tri-axis soft tactile sensors are presented and discussed. A moving least square approach is used to decouple and convert the magnetic field signal to force output to eliminate non-linearity and cross-talk effects. A case study of a tactile sensor prototype, MagOne, was developed. This achieved a resolution of 1.42 mN in normal force measurement (0.71 mN in shear force), good output repeatability and has a maximum hysteresis error of 3.4%. These results outperform comparable sensors reported previously, highlighting the efficacy of our methodology for sensor design. PMID:27563908

Resonant vibrating sensors for tactile tissue differentiation

NASA Astrophysics Data System (ADS)

Hemsel, T.; Stroop, R.; Oliva Uribe, D.; Wallaschek, J.

2007-12-01

Surgical resection of brain tumours is a difficult task. To enhance surgery results, a tactile sensor is wanted that gives better resolution and sensitivity than the human tactile sense. The characteristics of resonant vibrating piezoelectric elements change with varying load. This allows for calculation of mechanical load parameters by measuring electrical quantities. Different setups of piezoelectric sensors have been used to investigate soft materials. Finally, a piezoelectric bimorph sensor gave good results for distinguishing tissue mimicking gel-phantoms with different gelatine concentrations.

GelSight: High-Resolution Robot Tactile Sensors for Estimating Geometry and Force

PubMed Central

Yuan, Wenzhen; Dong, Siyuan; Adelson, Edward H.

2017-01-01

Tactile sensing is an important perception mode for robots, but the existing tactile technologies have multiple limitations. What kind of tactile information robots need, and how to use the information, remain open questions. We believe a soft sensor surface and high-resolution sensing of geometry should be important components of a competent tactile sensor. In this paper, we discuss the development of a vision-based optical tactile sensor, GelSight. Unlike the traditional tactile sensors which measure contact force, GelSight basically measures geometry, with very high spatial resolution. The sensor has a contact surface of soft elastomer, and it directly measures its deformation, both vertical and lateral, which corresponds to the exact object shape and the tension on the contact surface. The contact force, and slip can be inferred from the sensor’s deformation as well. Particularly, we focus on the hardware and software that support GelSight’s application on robot hands. This paper reviews the development of GelSight, with the emphasis in the sensing principle and sensor design. We introduce the design of the sensor’s optical system, the algorithm for shape, force and slip measurement, and the hardware designs and fabrication of different sensor versions. We also show the experimental evaluation on the GelSight’s performance on geometry and force measurement. With the high-resolution measurement of shape and contact force, the sensor has successfully assisted multiple robotic tasks, including material perception or recognition and in-hand localization for robot manipulation. PMID:29186053

Improved tactile resonance sensor for robotic assisted surgery

NASA Astrophysics Data System (ADS)

Oliva Uribe, David; Schoukens, Johan; Stroop, Ralf

2018-01-01

This paper presents an improved tactile sensor using a piezoelectric bimorph able to differentiate soft materials with similar mechanical characteristics. The final aim is to develop intelligent surgical tools for brain tumour resection using integrated sensors in order to improve tissue tumour delineation and tissue differentiation. The bimorph sensor is driven using a random phase multisine and the properties of contact between the sensor's tip and a certain load are evaluated by means of the evaluation of the nonparametric FRF. An analysis of the nonlinear contributions is presented to show that the use of a linear model is feasible for the measurement conditions. A series of gelatine phantoms were tested. The tactile sensor is able to identify minimal differences in the consistency of the measured samples considering viscoelastic behaviour. A variance analysis was performed to evaluate the reliability of the sensors and to identify possible error sources due to inconsistencies in the preparation method of the phantoms. The results of the variance analysis are discussed showing that ability of the proposed tactile sensor to perform high quality measurements.

Flexible PZT Thin Film Tactile Sensor for Biomedical Monitoring

PubMed Central

Tseng, Hong-Jie; Tian, Wei-Cheng; Wu, Wen-Jong

2013-01-01

This paper presents the development of tactile sensors using the sol-gel process to deposit a PZT thin-film from 250 nm to 1 μm on a flexible stainless steel substrate. The PZT thin-film tactile sensor can be used to measure human pulses from several areas, including carotid, brachial, finger, ankle, radial artery, and the apical region. Flexible PZT tactile sensors can overcome the diverse topology of various human regions and sense the corresponding signals from human bodies. The measured arterial pulse waveform can be used to diagnose hypertension and cardiac failure in patients. The proposed sensors have several advantages, such as flexibility, reliability, high strain, low cost, simple fabrication, and low temperature processing. The PZT thin-film deposition process includes a pyrolysis process at 150 °C/500 °C for 10/5 min, followed by an annealing process at 650 °C for 10 min. Finally, the consistent pulse wave velocity (PWV) was demonstrated based on human pulse measurements from apical to radial, brachial to radial, and radial to ankle. It is characterized that the sensitivity of our PZT-based tactile sensor was approximately 0.798 mV/g. PMID:23698262

Flexible PZT thin film tactile sensor for biomedical monitoring.

PubMed

Tseng, Hong-Jie; Tian, Wei-Cheng; Wu, Wen-Jong

2013-04-25

This paper presents the development of tactile sensors using the sol-gel process to deposit a PZT thin-film from 250 nm to 1 μm on a flexible stainless steel substrate. The PZT thin-film tactile sensor can be used to measure human pulses from several areas, including carotid, brachial, finger, ankle, radial artery, and the apical region. Flexible PZT tactile sensors can overcome the diverse topology of various human regions and sense the corresponding signals from human bodies. The measured arterial pulse waveform can be used to diagnose hypertension and cardiac failure in patients. The proposed sensors have several advantages, such as flexibility, reliability, high strain, low cost, simple fabrication, and low temperature processing. The PZT thin-film deposition process includes a pyrolysis process at 150 °C/500 °C for 10/5 min, followed by an annealing process at 650 °C for 10 min. Finally, the consistent pulse wave velocity (PWV) was demonstrated based on human pulse measurements from apical to radial, brachial to radial, and radial to ankle. It is characterized that the sensitivity of our PZT-based tactile sensor was approximately 0.798 mV/g.

Investigation and modification of a commercially available tactile sensor suited for robotic applications. Thesis

NASA Technical Reports Server (NTRS)

Creus, Carolina

1991-01-01

Active (dynamic) tactile sensing was explored using a commercially available tactile array sensor. This task requires the redesign of the sensor interface and a full understanding of the old sensor hardware implementation. There were different stages to this research; the first stage involved the reverse engineering of the old tactile sensor. The second stage had to do with the exploration of the characteristics and behavior of the tactile sensor pad. The next stage dealt with the redesign of the sensor interface using the knowledge gained from the previous two stages. Finally, in the last stage, software to control the tactile sensor was developed to aid in the data acquisition process.

Three Realizations and Comparison of Hardware for Piezoresistive Tactile Sensors

PubMed Central

Vidal-Verdú, Fernando; Oballe-Peinado, Óscar; Sánchez-Durán, José A.; Castellanos-Ramos, Julián; Navas-González, Rafael

2011-01-01

Tactile sensors are basically arrays of force sensors that are intended to emulate the skin in applications such as assistive robotics. Local electronics are usually implemented to reduce errors and interference caused by long wires. Realizations based on standard microcontrollers, Programmable Systems on Chip (PSoCs) and Field Programmable Gate Arrays (FPGAs) have been proposed by the authors for the case of piezoresistive tactile sensors. The solution employing FPGAs is especially relevant since their performance is closer to that of Application Specific Integrated Circuits (ASICs) than that of the other devices. This paper presents an implementation of such an idea for a specific sensor. For the purpose of comparison, the circuitry based on the other devices is also made for the same sensor. This paper discusses the implementation issues, provides details regarding the design of the hardware based on the three devices and compares them. PMID:22163797

An overview of tactile sensing

NASA Technical Reports Server (NTRS)

Agrawal, Rajeev; Jain, Ramesh

1986-01-01

Existing or proposed tactile sensors are reviewed. General considerations involved in tactile sensing and various performance criteria are discussed. Typical specifications to be expected from the sensors are also described. A representative set of present day tactile sensors is studied. Finally, some of the proposed recognition systems using tactile sensing are described.

A Prototype Tactile Sensor Array.

DTIC Science & Technology

1982-09-15

Active Touch Sensing. Technical Report, MIT Artificial Inteligence Laboratory, 1981. (9] Larcombe, M. Carbon Fibre Tactile Sensors. Technical Report...thesis, Carnegie-Mellon University, 1981. [13] Purbrick, John A. A Force Transducer Employing Conductive Silicone Rubber. Technical Report, MIT Artificial

An Experimental Optical Three-axis Tactile Sensor Featured with Hemispherical Surface

NASA Astrophysics Data System (ADS)

Ohka, Masahiro; Kobayashi, Hiroaki; Takata, Jumpei; Mitsuya, Yasunaga

We are developing an optical three-axis tactile sensor capable of acquiring normal and shearing force to mount on a robotic finger. The tactile sensor is based on the principle of an optical waveguide-type tactile sensor, which is composed of an acrylic hemispherical dome, a light source, an array of rubber sensing elements, and a CCD camera. The sensing element of the silicone rubber comprises one columnar feeler and eight conical feelers. The contact areas of the conical feelers, which maintain contact with the acrylic dome, detect the three-axis force applied to the tip of the sensing element. Normal and shearing forces are then calculated from integration and centroid displacement of the grayscale value derived from the conical feeler's contacts. To evaluate the present tactile sensor, we conducted a series of experiments using an x-z stage, a rotational stage, and a force gauge. Although we discovered that the relationship between the integrated grayscale value and normal force depends on the sensor's latitude on the hemispherical surface, it is easy to modify the sensitivity based on the latitude to make the centroid displacement of the grayscale value proportional to the shearing force. When we examined the repeatability of the present tactile sensor with 1,000 load/unload cycles, the error was 2%.

Optical based tactile shear and normal load sensor

DOEpatents

Salisbury, Curt Michael

2015-06-09

Various technologies described herein pertain to a tactile sensor that senses normal load and/or shear load. The tactile sensor includes a first layer and an optically transparent layer bonded together. At least a portion of the first layer is made of optically reflective material. The optically transparent layer is made of resilient material (e.g., clear silicone rubber). The tactile sensor includes light emitter/light detector pair(s), which respectively detect either normal load or shear load. Light emitter(s) emit light that traverses through the optically transparent layer and reflects off optically reflective material of the first layer, and light detector(s) detect and measure intensity of reflected light. When a normal load is applied, the optically transparent layer compresses, causing a change in reflected light intensity. When shear load is applied, a boundary between optically reflective material and optically absorptive material is laterally displaced, causing a change in reflected light intensity.

A flexible tactile sensitive sheet using a hetero-core fiber optic sensor

NASA Astrophysics Data System (ADS)

Fujino, S.; Yamazaki, H.; Hosoki, A.; Watanabe, K.

2014-05-01

In this report, we have designed a tactile sensitive sheet based on a hetero-core fiber-optic sensor, which realize an areal sensing by using single sensor potion in one optical fiber line. Recently, flexible and wide-area tactile sensing technology is expected to applied to acquired biological information in living space and robot achieve long-term care services such as welfare and nursing-care and humanoid technology. A hetero-core fiber-optic sensor has several advantages such as thin and flexible transmission line, immunity to EMI. Additionally this sensor is sensitive to moderate bending actions with optical loss changes and is independent of temperature fluctuation. Thus, the hetero-core fiber-optic sensor can be suitable for areal tactile sensing. We measure pressure characteristic of the proposed sensitive sheet by changing the pressure position and pinching characteristic on the surface. The proposed tactile sensitive sheet shows monotonic responses on the whole sensitive sheet surface although different sensitivity by the position is observed at the sensitive sheet surface. Moreover, the tactile sensitive sheet could sufficiently detect the pinching motion. In addition, in order to realize the discrimination between pressure and pinch, we fabricated a doubled-over sensor using a set of tactile sensitive sheets, which has different kinds of silicon robbers as a sensitive sheet surface. In conclusion, the flexible material could be given to the tactile sensation which is attached under proposed sensitive sheet.

Compact Tactile Sensors for Robot Fingers

NASA Technical Reports Server (NTRS)

Martin, Toby B.; Lussy, David; Gaudiano, Frank; Hulse, Aaron; Diftler, Myron A.; Rodriguez, Dagoberto; Bielski, Paul; Butzer, Melisa

2004-01-01

Compact transducer arrays that measure spatial distributions of force or pressure have been demonstrated as prototypes of tactile sensors to be mounted on fingers and palms of dexterous robot hands. The pressure- or force-distribution feedback provided by these sensors is essential for the further development and implementation of robot-control capabilities for humanlike grasping and manipulation.

A slow-adapting microfluidic-based tactile sensor

NASA Astrophysics Data System (ADS)

Tseng, W.-Y.; Fisher, J. S.; Prieto, J. L.; Rinaldi, K.; Alapati, G.; Lee, A. P.

2009-08-01

We present a microfluidic-based tactile sensor mimicking the human slow-adapting mechanoreceptor such as Merkel's disc. The sensor is composed of a polyimide (PI)/polydimethylsiloxane (PDMS) multilayer structure. The device uses a hemispherical reservoir filled with electrolyte solution in the PDMS layer, a microchannel in the PI layer and a pair of sensing electrodes below the microchannel as the force transducer. The tactile signal is detected as the impedance change resulting predominantly from the resistance variance due to the electrodes coverage by the 1M NaCl solution and is measured across the electrode pair. The sensor response is linear and the working range is shown to be in the range of 0-1.8 N. The characterization results also demonstrate the sensing of various levels of forces and its long-term signal stability.

A Novel Tactile Sensor with Electromagnetic Induction and Its Application on Stick-Slip Interaction Detection

PubMed Central

Liu, Yanjie; Han, Haijun; Liu, Tao; Yi, Jingang; Li, Qingguo; Inoue, Yoshio

2016-01-01

Real-time detection of contact states, such as stick-slip interaction between a robot and an object on its end effector, is crucial for the robot to grasp and manipulate the object steadily. This paper presents a novel tactile sensor based on electromagnetic induction and its application on stick-slip interaction. An equivalent cantilever-beam model of the tactile sensor was built and capable of constructing the relationship between the sensor output and the friction applied on the sensor. With the tactile sensor, a new method to detect stick-slip interaction on the contact surface between the object and the sensor is proposed based on the characteristics of friction change. Furthermore, a prototype was developed for a typical application, stable wafer transferring on a wafer transfer robot, by considering the spatial magnetic field distribution and the sensor size according to the requirements of wafer transfer. The experimental results validate the sensing mechanism of the tactile sensor and verify its feasibility of detecting stick-slip on the contact surface between the wafer and the sensor. The sensing mechanism also provides a new approach to detect the contact state on the soft-rigid surface in other robot-environment interaction systems. PMID:27023545

3D printed stretchable capacitive sensors for highly sensitive tactile and electrochemical sensing

NASA Astrophysics Data System (ADS)

Li, Kai; Wei, Hong; Liu, Wenguang; Meng, Hong; Zhang, Peixin; Yan, Chaoyi

2018-05-01

Developments of innovative strategies for the fabrication of stretchable sensors are of crucial importance for their applications in wearable electronic systems. In this work, we report the successful fabrication of stretchable capacitive sensors using a novel 3D printing method for highly sensitive tactile and electrochemical sensing applications. Unlike conventional lithographic or templated methods, the programmable 3D printing technique can fabricate complex device structures in a cost-effective and facile manner. We designed and fabricated stretchable capacitive sensors with interdigital and double-vortex designs and demonstrated their successful applications as tactile and electrochemical sensors. Especially, our stretchable sensors exhibited a detection limit as low as 1 × 10-6 M for NaCl aqueous solution, which could have significant potential applications when integrated in electronics skins.

Microstructured graphene arrays for highly sensitive flexible tactile sensors.

PubMed

Zhu, Bowen; Niu, Zhiqiang; Wang, Hong; Leow, Wan Ru; Wang, Hua; Li, Yuangang; Zheng, Liyan; Wei, Jun; Huo, Fengwei; Chen, Xiaodong

2014-09-24

A highly sensitive tactile sensor is devised by applying microstructured graphene arrays as sensitive layers. The combination of graphene and anisotropic microstructures endows this sensor with an ultra-high sensitivity of -5.53 kPa(-1) , an ultra-fast response time of only 0.2 ms, as well as good reliability, rendering it promising for the application of tactile sensing in artificial skin and human-machine interface. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Artificial Roughness Encoding with a Bio-inspired MEMS- based Tactile Sensor Array

PubMed Central

Oddo, Calogero Maria; Beccai, Lucia; Felder, Martin; Giovacchini, Francesco; Carrozza, Maria Chiara

2009-01-01

A compliant 2×2 tactile sensor array was developed and investigated for roughness encoding. State of the art cross shape 3D MEMS sensors were integrated with polymeric packaging providing in total 16 sensitive elements to external mechanical stimuli in an area of about 20 mm2, similarly to the SA1 innervation density in humans. Experimental analysis of the bio-inspired tactile sensor array was performed by using ridged surfaces, with spatial periods from 2.6 mm to 4.1 mm, which were indented with regulated 1N normal force and stroked at constant sliding velocity from 15 mm/s to 48 mm/s. A repeatable and expected frequency shift of the sensor outputs depending on the applied stimulus and on its scanning velocity was observed between 3.66 Hz and 18.46 Hz with an overall maximum error of 1.7%. The tactile sensor could also perform contact imaging during static stimulus indentation. The experiments demonstrated the suitability of this approach for the design of a roughness encoding tactile sensor for an artificial fingerpad. PMID:22412304

3D printed stretchable capacitive sensors for highly sensitive tactile and electrochemical sensing.

PubMed

Li, Kai; Wei, Hong; Liu, Wenguang; Meng, Hong; Zhang, Peixin; Yan, Chaoyi

2018-05-04

Developments of innovative strategies for the fabrication of stretchable sensors are of crucial importance for their applications in wearable electronic systems. In this work, we report the successful fabrication of stretchable capacitive sensors using a novel 3D printing method for highly sensitive tactile and electrochemical sensing applications. Unlike conventional lithographic or templated methods, the programmable 3D printing technique can fabricate complex device structures in a cost-effective and facile manner. We designed and fabricated stretchable capacitive sensors with interdigital and double-vortex designs and demonstrated their successful applications as tactile and electrochemical sensors. Especially, our stretchable sensors exhibited a detection limit as low as 1 × 10 -6 M for NaCl aqueous solution, which could have significant potential applications when integrated in electronics skins.

Slip detection with accelerometer and tactile sensors in a robotic hand model

NASA Astrophysics Data System (ADS)

Al-Shanoon, Abdulrahman Abdulkareem S.; Anom Ahmad, Siti; Hassan, Mohd. Khair b.

2015-11-01

Grasp planning is an interesting issue in studies that dedicated efforts to investigate tactile sensors. This study investigated the physical force interaction between a tactile pressure sensor and a particular object. It also characterized object slipping during gripping operations and presented secure regripping of an object. Acceleration force was analyzed using an accelerometer sensor to establish a completely autonomous robotic hand model. An automatic feedback control system was applied to regrip the particular object when it commences to slip. Empirical findings were presented in consideration of the detection and subsequent control of the slippage situation. These findings revealed the correlation between the distance of the object slipping and the required force to regrip the object safely. This approach is similar to Hooke's law formula.

The TacTip Family: Soft Optical Tactile Sensors with 3D-Printed Biomimetic Morphologies

PubMed Central

Pestell, Nicholas; Cramphorn, Luke; Winstone, Benjamin; Giannaccini, Maria Elena; Rossiter, Jonathan; Lepora, Nathan F.

2018-01-01

Abstract Tactile sensing is an essential component in human–robot interaction and object manipulation. Soft sensors allow for safe interaction and improved gripping performance. Here we present the TacTip family of sensors: a range of soft optical tactile sensors with various morphologies fabricated through dual-material 3D printing. All of these sensors are inspired by the same biomimetic design principle: transducing deformation of the sensing surface via movement of pins analogous to the function of intermediate ridges within the human fingertip. The performance of the TacTip, TacTip-GR2, TacTip-M2, and TacCylinder sensors is here evaluated and shown to attain submillimeter accuracy on a rolling cylinder task, representing greater than 10-fold super-resolved acuity. A version of the TacTip sensor has also been open-sourced, enabling other laboratories to adopt it as a platform for tactile sensing and manipulation research. These sensors are suitable for real-world applications in tactile perception, exploration, and manipulation, and will enable further research and innovation in the field of soft tactile sensing. PMID:29297773

The TacTip Family: Soft Optical Tactile Sensors with 3D-Printed Biomimetic Morphologies.

PubMed

Ward-Cherrier, Benjamin; Pestell, Nicholas; Cramphorn, Luke; Winstone, Benjamin; Giannaccini, Maria Elena; Rossiter, Jonathan; Lepora, Nathan F

2018-04-01

Tactile sensing is an essential component in human-robot interaction and object manipulation. Soft sensors allow for safe interaction and improved gripping performance. Here we present the TacTip family of sensors: a range of soft optical tactile sensors with various morphologies fabricated through dual-material 3D printing. All of these sensors are inspired by the same biomimetic design principle: transducing deformation of the sensing surface via movement of pins analogous to the function of intermediate ridges within the human fingertip. The performance of the TacTip, TacTip-GR2, TacTip-M2, and TacCylinder sensors is here evaluated and shown to attain submillimeter accuracy on a rolling cylinder task, representing greater than 10-fold super-resolved acuity. A version of the TacTip sensor has also been open-sourced, enabling other laboratories to adopt it as a platform for tactile sensing and manipulation research. These sensors are suitable for real-world applications in tactile perception, exploration, and manipulation, and will enable further research and innovation in the field of soft tactile sensing.

Spatially digitized tactile pressure sensors with tunable sensitivity and sensing range.

PubMed

Choi, Eunsuk; Sul, Onejae; Hwang, Soonhyung; Cho, Joonhyung; Chun, Hyunsuk; Kim, Hongjun; Lee, Seung-Beck

2014-10-24

When developing an electronic skin with touch sensation, an array of tactile pressure sensors with various ranges of pressure detection need to be integrated. This requires low noise, highly reliable sensors with tunable sensing characteristics. We demonstrate the operation of tactile pressure sensors that utilize the spatial distribution of contact electrodes to detect various ranges of tactile pressures. The device consists of a suspended elastomer diaphragm, with a carbon nanotube thin-film on the bottom, which makes contact with the electrodes on the substrate with applied pressure. The electrodes separated by set distances become connected in sequence with tactile pressure, enabling consecutive electrodes to produce a signal. Thus, the pressure is detected not by how much of a signal is produced but by which of the electrodes is registering an output. By modulating the diaphragm diameter, and suspension height, it was possible to tune the pressure sensitivity and sensing range. Also, adding a fingerprint ridge structure enabled the sensor to detect the periodicity of sub-millimeter grating patterns on a silicon wafer.

A Large Area Tactile Sensor Patch Based on Commercial Force Sensors

PubMed Central

Vidal-Verdú, Fernando; Barquero, Maria Jose; Castellanos-Ramos, Julián; Navas-González, Rafael; Sánchez, Jose Antonio; Serón, Javier; García-Cerezo, Alfonso

2011-01-01

This paper reports the design of a tactile sensor patch to cover large areas of robots and machines that interact with human beings. Many devices have been proposed to meet such a demand. These realizations are mostly custom-built or developed in the lab. The sensor of this paper is implemented with commercial force sensors. This has the benefit of a more foreseeable response of the sensor if its behavior is understood as the aggregation of readings from all the individual force sensors in the array. A few reported large area tactile sensors are also based on commercial sensors. However, the one in this paper is the first of this kind based on the use of polymeric commercial force sensing resistors (FSR) as unit elements of the array or tactels, which results in a robust sensor. The paper discusses design issues related to some necessary modifications of the force sensor, its assembly in an array, and the signal conditioning. The patch has 16 × 9 force sensors mounted on a flexible printed circuit board with a spatial resolution of 18.5 mm. The force range of a tactel is 6 N and its sensitivity is 0.6 V/N. The array is read at a rate of 78 frames per second. Finally, two simple application examples are also carried out with the sensor mounted on the forearm of a rescue robot that communicates with the sensor through a CAN bus. PMID:22163910

Advances in Bio-Tactile Sensors for Minimally Invasive Surgery Using the Fibre Bragg Grating Force Sensor Technique:A Survey

PubMed Central

Abushagur, Abdulfatah A.G.; Arsad, Norhana; Ibne Reaz, Mamun; Ashrif, A.; Bakar, A.

2014-01-01

The large interest in utilising fibre Bragg grating (FBG) strain sensors for minimally invasive surgery (MIS) applications to replace conventional electrical tactile sensors has grown in the past few years. FBG strain sensors offer the advantages of optical fibre sensors, such as high sensitivity, immunity to electromagnetic noise, electrical passivity and chemical inertness, but are not limited by phase discontinuity or intensity fluctuations. FBG sensors feature a wavelength-encoding sensing signal that enables distributed sensing that utilises fewer connections. In addition, their flexibility and lightness allow easy insertion into needles and catheters, thus enabling localised measurements inside tissues and blood. Two types of FBG tactile sensors have been emphasised in the literature: single-point and array FBG tactile sensors. This paper describes the current design, development and research of the optical fibre tactile techniques that are based on FBGs to enhance the performance of MIS procedures in general. Providing MIS or microsurgery surgeons with accurate and precise measurements and control of the contact forces during tissues manipulation will benefit both surgeons and patients. PMID:24721774

A Magnetoresistive Tactile Sensor for Harsh Environment Applications

PubMed Central

Alfadhel, Ahmed; Khan, Mohammed Asadullah; Cardoso, Susana; Leitao, Diana; Kosel, Jürgen

2016-01-01

A magnetoresistive tactile sensor is reported, which is capable of working in high temperatures up to 140 °C. Hair-like bioinspired structures, known as cilia, made out of permanent magnetic nanocomposite material on top of spin-valve giant magnetoresistive (GMR) sensors are used for tactile sensing at high temperatures. The magnetic nanocomposite, consisting of iron nanowires incorporated into the polymer polydimethylsiloxane (PDMS), is very flexible, biocompatible, has high remanence, and is also resilient to antagonistic sensing ambient. When the cilia come in contact with a surface, they deflect in compliance with the surface topology. This yields a change of the GMR sensor signal, enabling the detection of extremely fine features. The spin-valve is covered with a passivation layer, which enables adequate performance in spite of harsh environmental conditions, as demonstrated in this paper for high temperature. PMID:27164113

Computational Intelligence Techniques for Tactile Sensing Systems

PubMed Central

Gastaldo, Paolo; Pinna, Luigi; Seminara, Lucia; Valle, Maurizio; Zunino, Rodolfo

2014-01-01

Tactile sensing helps robots interact with humans and objects effectively in real environments. Piezoelectric polymer sensors provide the functional building blocks of the robotic electronic skin, mainly thanks to their flexibility and suitability for detecting dynamic contact events and for recognizing the touch modality. The paper focuses on the ability of tactile sensing systems to support the challenging recognition of certain qualities/modalities of touch. The research applies novel computational intelligence techniques and a tensor-based approach for the classification of touch modalities; its main results consist in providing a procedure to enhance system generalization ability and architecture for multi-class recognition applications. An experimental campaign involving 70 participants using three different modalities in touching the upper surface of the sensor array was conducted, and confirmed the validity of the approach. PMID:24949646

Computational intelligence techniques for tactile sensing systems.

PubMed

Gastaldo, Paolo; Pinna, Luigi; Seminara, Lucia; Valle, Maurizio; Zunino, Rodolfo

2014-06-19

Tactile sensing helps robots interact with humans and objects effectively in real environments. Piezoelectric polymer sensors provide the functional building blocks of the robotic electronic skin, mainly thanks to their flexibility and suitability for detecting dynamic contact events and for recognizing the touch modality. The paper focuses on the ability of tactile sensing systems to support the challenging recognition of certain qualities/modalities of touch. The research applies novel computational intelligence techniques and a tensor-based approach for the classification of touch modalities; its main results consist in providing a procedure to enhance system generalization ability and architecture for multi-class recognition applications. An experimental campaign involving 70 participants using three different modalities in touching the upper surface of the sensor array was conducted, and confirmed the validity of the approach.

3D Printed Stretchable Tactile Sensors.

PubMed

Guo, Shuang-Zhuang; Qiu, Kaiyan; Meng, Fanben; Park, Sung Hyun; McAlpine, Michael C

2017-07-01

The development of methods for the 3D printing of multifunctional devices could impact areas ranging from wearable electronics and energy harvesting devices to smart prosthetics and human-machine interfaces. Recently, the development of stretchable electronic devices has accelerated, concomitant with advances in functional materials and fabrication processes. In particular, novel strategies have been developed to enable the intimate biointegration of wearable electronic devices with human skin in ways that bypass the mechanical and thermal restrictions of traditional microfabrication technologies. Here, a multimaterial, multiscale, and multifunctional 3D printing approach is employed to fabricate 3D tactile sensors under ambient conditions conformally onto freeform surfaces. The customized sensor is demonstrated with the capabilities of detecting and differentiating human movements, including pulse monitoring and finger motions. The custom 3D printing of functional materials and devices opens new routes for the biointegration of various sensors in wearable electronics systems, and toward advanced bionic skin applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Sensor chip and apparatus for tactile and/or flow sensing

NASA Technical Reports Server (NTRS)

Liu, Chang (Inventor); Chen, Jack (Inventor); Engel, Jonathan (Inventor)

2008-01-01

A sensor chip, comprising a flexible, polymer-based substrate, and at least one microfabricated sensor disposed on the substrate and including a conductive element. The at least one sensor comprises at least one of a tactile sensor and a flow sensor. Other embodiments of the present invention include sensors and/or multi-modal sensor nodes.

Sensor chip and apparatus for tactile and/or flow sensing

NASA Technical Reports Server (NTRS)

Liu, Chang (Inventor); Chen, Jack (Inventor); Engel, Jonathan (Inventor)

2009-01-01

A sensor chip, comprising a flexible, polymer-based substrate, and at least one microfabricated sensor disposed on the substrate and including a conductive element. The at least one sensor comprises at least one of a tactile sensor and a flow sensor. Other embodiments of the present invention include sensors and/or multi-modal sensor nodes.

Remotely deployable aerial inspection using tactile sensors

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

MacLeod, C. N.; Cao, J.; Pierce, S. G.

For structural monitoring applications, the use of remotely deployable Non-Destructive Evaluation (NDE) inspection platforms offer many advantages, including improved accessibility, greater safety and reduced cost, when compared to traditional manual inspection techniques. The use of such platforms, previously reported by researchers at the University Strathclyde facilitates the potential for rapid scanning of large areas and volumes in hazardous locations. A common problem for both manual and remote deployment approaches lies in the intrinsic stand-off and surface coupling issues of typical NDE probes. The associated complications of these requirements are obviously significantly exacerbated when considering aerial based remote inspection and deployment,more » resulting in simple visual techniques being the preferred sensor payload. Researchers at Bristol Robotics Laboratory have developed biomimetic tactile sensors modelled on the facial whiskers (vibrissae) of animals such as rats and mice, with the latest sensors actively sweeping their tips across the surface in a back and forth motion. The current work reports on the design and performance of an aerial inspection platform and the suitability of tactile whisking sensors to aerial based surface monitoring applications.« less

Modeling and optimal design of an optical MEMS tactile sensor for use in robotically assisted surgery

NASA Astrophysics Data System (ADS)

Ahmadi, Roozbeh; Kalantari, Masoud; Packirisamy, Muthukumaran; Dargahi, Javad

2010-06-01

Currently, Minimally Invasive Surgery (MIS) performs through keyhole incisions using commercially available robotic surgery systems. One of the most famous examples of these robotic surgery systems is the da Vinci surgical system. In the current robotic surgery systems like the da Vinci, surgeons are faced with problems such as lack of tactile feedback during the surgery. Therefore, providing a real-time tactile feedback from interaction between surgical instruments and tissue can help the surgeons to perform MIS more reliably. The present paper proposes an optical tactile sensor to measure the contact force between the bio-tissue and the surgical instrument. A model is proposed for simulating the interaction between a flexible membrane and bio-tissue based on the finite element methods. The tissue is considered as a hyperelastic material with the material properties similar to the heart tissue. The flexible membrane is assumed as a thin layer of silicon which can be microfabricated using the technology of Micro Electro Mechanical Systems (MEMS). The simulation results are used to optimize the geometric design parameters of a proposed MEMS tactile sensor for use in robotic surgical systems to perform MIS.

Compliant tactile sensor that delivers a force vector

NASA Technical Reports Server (NTRS)

Torres-Jara, Eduardo (Inventor)

2010-01-01

Tactile Sensor. The sensor includes a compliant convex surface disposed above a sensor array, the sensor array adapted to respond to deformation of the convex surface to generate a signal related to an applied force vector. The applied force vector has three components to establish the direction and magnitude of an applied force. The compliant convex surface defines a dome with a hollow interior and has a linear relation between displacement and load including a magnet disposed substantially at the center of the dome above a sensor array that responds to magnetic field intensity.

A flexible dual mode tactile and proximity sensor using carbon microcoils

NASA Astrophysics Data System (ADS)

Han, Hyo Seung; Park, Junwoo; Nguyen, Tien Dat; Kim, Uikyum; Jeong, Soon Cheol; Kang, Doo In; Choi, Hyouk Ryeol

2016-04-01

This paper proposes a flexible dual mode tactile and proximity sensor using Carbon Microcoils (CMCs). The sensor consists of a Flexible Printed Circuit Board (FPCB) electrode layer and a dielectric layer of CMCs composite. In order to avoid damage from frequent contacts, the sensor has all electrodes on the same plane and a polymer covering is placed on the top of the sensor. CMCs can be modeled as complex LCR circuit and the sensitivity of the sensor highly depends on the CMC content. Proper CMC content is experimentally investigated and applied to make the CMCs composite for the dielectric layer. The CMC sensor measures the capacitance for tactile stimulus and inductance for proximity stimulus. A prototype with a size of 30 × 30 × 0.6 𝑚𝑚3, is manufactured and its feasibility is experimentally validated.

Compliant tactile sensor for generating a signal related to an applied force

NASA Technical Reports Server (NTRS)

Torres-Jara, Eduardo (Inventor)

2012-01-01

Tactile sensor. The sensor includes a compliant convex surface disposed above a sensor array, the sensor array adapted to respond to deformation of the convex surface to generate a signal related to an applied force vector.

An Extreme Learning Machine-Based Neuromorphic Tactile Sensing System for Texture Recognition.

PubMed

Rasouli, Mahdi; Chen, Yi; Basu, Arindam; Kukreja, Sunil L; Thakor, Nitish V

2018-04-01

Despite significant advances in computational algorithms and development of tactile sensors, artificial tactile sensing is strikingly less efficient and capable than the human tactile perception. Inspired by efficiency of biological systems, we aim to develop a neuromorphic system for tactile pattern recognition. We particularly target texture recognition as it is one of the most necessary and challenging tasks for artificial sensory systems. Our system consists of a piezoresistive fabric material as the sensor to emulate skin, an interface that produces spike patterns to mimic neural signals from mechanoreceptors, and an extreme learning machine (ELM) chip to analyze spiking activity. Benefiting from intrinsic advantages of biologically inspired event-driven systems and massively parallel and energy-efficient processing capabilities of the ELM chip, the proposed architecture offers a fast and energy-efficient alternative for processing tactile information. Moreover, it provides the opportunity for the development of low-cost tactile modules for large-area applications by integration of sensors and processing circuits. We demonstrate the recognition capability of our system in a texture discrimination task, where it achieves a classification accuracy of 92% for categorization of ten graded textures. Our results confirm that there exists a tradeoff between response time and classification accuracy (and information transfer rate). A faster decision can be achieved at early time steps or by using a shorter time window. This, however, results in deterioration of the classification accuracy and information transfer rate. We further observe that there exists a tradeoff between the classification accuracy and the input spike rate (and thus energy consumption). Our work substantiates the importance of development of efficient sparse codes for encoding sensory data to improve the energy efficiency. These results have a significance for a wide range of wearable, robotic

Design Optimisation of a Magnetic Field Based Soft Tactile Sensor

PubMed Central

Raske, Nicholas; Kow, Junwai; Alazmani, Ali; Ghajari, Mazdak; Culmer, Peter; Hewson, Robert

2017-01-01

This paper investigates the design optimisation of a magnetic field based soft tactile sensor, comprised of a magnet and Hall effect module separated by an elastomer. The aim was to minimise sensitivity of the output force with respect to the input magnetic field; this was achieved by varying the geometry and material properties. Finite element simulations determined the magnetic field and structural behaviour under load. Genetic programming produced phenomenological expressions describing these responses. Optimisation studies constrained by a measurable force and stable loading conditions were conducted; these produced Pareto sets of designs from which the optimal sensor characteristics were selected. The optimisation demonstrated a compromise between sensitivity and the measurable force, a fabricated version of the optimised sensor validated the improvements made using this methodology. The approach presented can be applied in general for optimising soft tactile sensor designs over a range of applications and sensing modes. PMID:29099787

Tactile sensor of hardness recognition based on magnetic anomaly detection

NASA Astrophysics Data System (ADS)

Xue, Lingyun; Zhang, Dongfang; Chen, Qingguang; Rao, Huanle; Xu, Ping

2018-03-01

Hardness, as one kind of tactile sensing, plays an important role in the field of intelligent robot application such as gripping, agricultural harvesting, prosthetic hand and so on. Recently, with the rapid development of magnetic field sensing technology with high performance, a number of magnetic sensors have been developed for intelligent application. The tunnel Magnetoresistance(TMR) based on magnetoresistance principal works as the sensitive element to detect the magnetic field and it has proven its excellent ability of weak magnetic detection. In the paper, a new method based on magnetic anomaly detection was proposed to detect the hardness in the tactile way. The sensor is composed of elastic body, ferrous probe, TMR element, permanent magnet. When the elastic body embedded with ferrous probe touches the object under the certain size of force, deformation of elastic body will produce. Correspondingly, the ferrous probe will be forced to displace and the background magnetic field will be distorted. The distorted magnetic field was detected by TMR elements and the output signal at different time can be sampled. The slope of magnetic signal with the sampling time is different for object with different hardness. The result indicated that the magnetic anomaly sensor can recognize the hardness rapidly within 150ms after the tactile moment. The hardness sensor based on magnetic anomaly detection principal proposed in the paper has the advantages of simple structure, low cost, rapid response and it has shown great application potential in the field of intelligent robot.

Tactile-STAR: A Novel Tactile STimulator And Recorder System for Evaluating and Improving Tactile Perception.

PubMed

Ballardini, Giulia; Carlini, Giorgio; Giannoni, Psiche; Scheidt, Robert A; Nisky, Ilana; Casadio, Maura

2018-01-01

Many neurological diseases impair the motor and somatosensory systems. While several different technologies are used in clinical practice to assess and improve motor functions, somatosensation is evaluated subjectively with qualitative clinical scales. Treatment of somatosensory deficits has received limited attention. To bridge the gap between the assessment and training of motor vs. somatosensory abilities, we designed, developed, and tested a novel, low-cost, two-component (bimanual) mechatronic system targeting tactile somatosensation: the Tactile-STAR -a tactile stimulator and recorder. The stimulator is an actuated pantograph structure driven by two servomotors, with an end-effector covered by a rubber material that can apply two different types of skin stimulation: brush and stretch. The stimulator has a modular design, and can be used to test the tactile perception in different parts of the body such as the hand, arm, leg, big toe, etc. The recorder is a passive pantograph that can measure hand motion using two potentiometers. The recorder can serve multiple purposes: participants can move its handle to match the direction and amplitude of the tactile stimulator, or they can use it as a master manipulator to control the tactile stimulator as a slave. Our ultimate goal is to assess and affect tactile acuity and somatosensory deficits. To demonstrate the feasibility of our novel system, we tested the Tactile-STAR with 16 healthy individuals and with three stroke survivors using the skin-brush stimulation. We verified that the system enables the mapping of tactile perception on the hand in both populations. We also tested the extent to which 30 min of training in healthy individuals led to an improvement of tactile perception. The results provide a first demonstration of the ability of this new system to characterize tactile perception in healthy individuals, as well as a quantification of the magnitude and pattern of tactile impairment in a small cohort of

A Finger-Shaped Tactile Sensor for Fabric Surfaces Evaluation by 2-Dimensional Active Sliding Touch

PubMed Central

Hu, Haihua; Han, Yezhen; Song, Aiguo; Chen, Shanguang; Wang, Chunhui; Wang, Zheng

2014-01-01

Sliding tactile perception is a basic function for human beings to determine the mechanical properties of object surfaces and recognize materials. Imitating this process, this paper proposes a novel finger-shaped tactile sensor based on a thin piezoelectric polyvinylidene fluoride (PVDF) film for surface texture measurement. A parallelogram mechanism is designed to ensure that the sensor applies a constant contact force perpendicular to the object surface, and a 2-dimensional movable mechanical structure is utilized to generate the relative motion at a certain speed between the sensor and the object surface. By controlling the 2-dimensional motion of the finger-shaped sensor along the object surface, small height/depth variation of surface texture changes the output charge of PVDF film then surface texture can be measured. In this paper, the finger-shaped tactile sensor is used to evaluate and classify five different kinds of linen. Fast Fourier Transformation (FFT) is utilized to get original attribute data of surface in the frequency domain, and principal component analysis (PCA) is used to compress the attribute data and extract feature information. Finally, low dimensional features are classified by Support Vector Machine (SVM). The experimental results show that this finger-shaped tactile sensor is effective and high accurate for discriminating the five textures. PMID:24618775

A finger-shaped tactile sensor for fabric surfaces evaluation by 2-dimensional active sliding touch.

PubMed

Hu, Haihua; Han, Yezhen; Song, Aiguo; Chen, Shanguang; Wang, Chunhui; Wang, Zheng

2014-03-11

Sliding tactile perception is a basic function for human beings to determine the mechanical properties of object surfaces and recognize materials. Imitating this process, this paper proposes a novel finger-shaped tactile sensor based on a thin piezoelectric polyvinylidene fluoride (PVDF) film for surface texture measurement. A parallelogram mechanism is designed to ensure that the sensor applies a constant contact force perpendicular to the object surface, and a 2-dimensional movable mechanical structure is utilized to generate the relative motion at a certain speed between the sensor and the object surface. By controlling the 2-dimensional motion of the finger-shaped sensor along the object surface, small height/depth variation of surface texture changes the output charge of PVDF film then surface texture can be measured. In this paper, the finger-shaped tactile sensor is used to evaluate and classify five different kinds of linen. Fast Fourier Transformation (FFT) is utilized to get original attribute data of surface in the frequency domain, and principal component analysis (PCA) is used to compress the attribute data and extract feature information. Finally, low dimensional features are classified by Support Vector Machine (SVM). The experimental results show that this finger-shaped tactile sensor is effective and high accurate for discriminating the five textures.

Fully printed flexible fingerprint-like three-axis tactile and slip force and temperature sensors for artificial skin.

PubMed

Harada, Shingo; Kanao, Kenichiro; Yamamoto, Yuki; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

2014-12-23

A three-axis tactile force sensor that determines the touch and slip/friction force may advance artificial skin and robotic applications by fully imitating human skin. The ability to detect slip/friction and tactile forces simultaneously allows unknown objects to be held in robotic applications. However, the functionalities of flexible devices have been limited to a tactile force in one direction due to difficulties fabricating devices on flexible substrates. Here we demonstrate a fully printed fingerprint-like three-axis tactile force and temperature sensor for artificial skin applications. To achieve economic macroscale devices, these sensors are fabricated and integrated using only printing methods. Strain engineering enables the strain distribution to be detected upon applying a slip/friction force. By reading the strain difference at four integrated force sensors for a pixel, both the tactile and slip/friction forces can be analyzed simultaneously. As a proof of concept, the high sensitivity and selectivity for both force and temperature are demonstrated using a 3×3 array artificial skin that senses tactile, slip/friction, and temperature. Multifunctional sensing components for a flexible device are important advances for both practical applications and basic research in flexible electronics.

Development of CMOS MEMS inductive type tactile sensor with the integration of chrome steel ball force interface

NASA Astrophysics Data System (ADS)

Yeh, Sheng-Kai; Chang, Heng-Chung; Fang, Weileun

2018-04-01

This study presents an inductive tactile sensor with a chrome steel ball sensing interface based on the commercially available standard complementary metal-oxide-semiconductor (CMOS) process (the TSMC 0.18 µm 1P6M CMOS process). The tactile senor has a deformable polymer layer as the spring of the device and no fragile suspended thin film structures are required. As a tactile force is applied on the chrome steel ball, the polymer would deform. The distance between the chrome steel ball and the sensing coil would changed. Thus, the tactile force can be detected by the inductance change of the sensing coil. In short, the chrome steel ball acts as a tactile bump as well as the sensing interface. Experimental results show that the proposed inductive tactile sensor has a sensing range of 0-1.4 N with a sensitivity of 9.22(%/N) and nonlinearity of 2%. Preliminary wireless sensing test is also demonstrated. Moreover, the influence of the process and material issues on the sensor performances have also been investigated.

Using a high spatial resolution tactile sensor for intention detection.

PubMed

Castellini, Claudio; Koiva, Risto

2013-06-01

Intention detection is the interpretation of biological signals with the aim of automatically, reliably and naturally understanding what a human subject desires to do. Although intention detection is not restricted to disabled people, such methods can be crucial in improving a patient's life, e.g., aiding control of a robotic wheelchair or of a self-powered prosthesis. Traditionally, intention detection is done using, e.g., gaze tracking, surface electromyography and electroencephalography. In this paper we present exciting initial results of an experiment aimed at intention detection using a high-spatial-resolution, high-dynamic-range tactile sensor. The tactile image of the ventral side of the forearm of 9 able-bodied participants was recorded during a variable-force task stimulated at the fingertip. Both the forces at the fingertip and at the forearm were synchronously recorded. We show that a standard dimensionality reduction technique (Principal Component Analysis) plus a Support Vector Machine attain almost perfect detection accuracy of the direction and the intensity of the intended force. This paves the way for high spatial resolution tactile sensors to be used as a means for intention detection.

Artificial tactile sensing in minimally invasive surgery - a new technical approach.

PubMed

Schostek, Sebastian; Ho, Chi-Nghia; Kalanovic, Daniel; Schurr, Marc O

2006-01-01

The loss of tactile sensation is a commonly known drawback of minimally invasive surgery (MIS). Since the advent of MIS, research activities in providing tactile information to the surgeon are still ongoing, in order to improve patient safety and to extend the indications for MIS. We have designed a tactile sensor system comprising a tactile laparoscopic grasper for surgical palpation. For this purpose, we developed a novel tactile sensor technology which allows the manufacturing of an integrated sensor array within an acceptable price range. The array was integrated into the jaws of a 10mm laparoscopic grasper. The tactile data are transferred wirelessly via Bluetooth and are presented visually to the surgeon. The goal was to be able to obtain information about the shape and consistency of tissue structures by gently compressing the tissue between the jaws of the tactile instrument and thus to be able to recognize and assess anatomical or pathological structures, even if they are hidden in the tissue. With a prototype of the tactile sensor system we have conducted bench-tests as well as in-vitro and in-vivo experiments. The system proved feasibility in an experimental environment, it was easy to use, and the novel tactile sensor array was applicable for both palpation and grasping manoeuvres with forces of up to 60N. The tactile data turned out to be a useful supplement to the minimal amount of haptic feedback that is provided by current endoscopic instruments and the endoscopic image under certain conditions.

An insect-inspired bionic sensor for tactile localization and material classification with state-dependent modulation

PubMed Central

Patanè, Luca; Hellbach, Sven; Krause, André F.; Arena, Paolo; Dürr, Volker

2012-01-01

Insects carry a pair of antennae on their head: multimodal sensory organs that serve a wide range of sensory-guided behaviors. During locomotion, antennae are involved in near-range orientation, for example in detecting, localizing, probing, and negotiating obstacles. Here we present a bionic, active tactile sensing system inspired by insect antennae. It comprises an actuated elastic rod equipped with a terminal acceleration sensor. The measurement principle is based on the analysis of damped harmonic oscillations registered upon contact with an object. The dominant frequency of the oscillation is extracted to determine the distance of the contact point along the probe and basal angular encoders allow tactile localization in a polar coordinate system. Finally, the damping behavior of the registered signal is exploited to determine the most likely material. The tactile sensor is tested in four approaches with increasing neural plausibility: first, we show that peak extraction from the Fourier spectrum is sufficient for tactile localization with position errors below 1%. Also, the damping property of the extracted frequency is used for material classification. Second, we show that the Fourier spectrum can be analysed by an Artificial Neural Network (ANN) which can be trained to decode contact distance and to classify contact materials. Thirdly, we show how efficiency can be improved by band-pass filtering the Fourier spectrum by application of non-negative matrix factorization. This reduces the input dimension by 95% while reducing classification performance by 8% only. Finally, we replace the FFT by an array of spiking neurons with gradually differing resonance properties, such that their spike rate is a function of the input frequency. We show that this network can be applied to detect tactile contact events of a wheeled robot, and how detrimental effects of robot velocity on antennal dynamics can be suppressed by state-dependent modulation of the input signals

Tactile Data Entry System

NASA Technical Reports Server (NTRS)

Adams, Richard J.

2015-01-01

The patent-pending Glove-Enabled Computer Operations (GECO) design leverages extravehicular activity (EVA) glove design features as platforms for instrumentation and tactile feedback, enabling the gloves to function as human-computer interface devices. Flexible sensors in each finger enable control inputs that can be mapped to any number of functions (e.g., a mouse click, a keyboard strike, or a button press). Tracking of hand motion is interpreted alternatively as movement of a mouse (change in cursor position on a graphical user interface) or a change in hand position on a virtual keyboard. Programmable vibro-tactile actuators aligned with each finger enrich the interface by creating the haptic sensations associated with control inputs, such as recoil of a button press.

A multifunctional PVDF-based tactile sensor for minimally invasive surgery

NASA Astrophysics Data System (ADS)

Sokhanvar, S.; Packirisamy, M.; Dargahi, J.

2007-08-01

In this paper a multifunctional tactile sensor system using PVDF (polyvinylidene fluoride), is proposed, designed, analyzed, tested and validated. The working principle of the sensor is in such a way that it can be used in combination with almost any end-effectors. However, the sensor is particularly designed to be integrated with minimally invasive surgery (MIS) tools. In addition, the structural and transduction materials are selected to be compatible with micro-electro-mechanical systems (MEMS) technology, so that miniaturization would be possible. The corrugated shape of the sensor ensures the safe tissue grasping and compatibility with the traditional tooth-like end effectors of MIS tools. A unit of this sensor comprised of a base, a flexible beam and three PVDF sensing elements. Two PVDF sensing elements sandwiched at the end supports work in thickness mode to measure the magnitude and position of applied load. The third PVDF sensing element is attached to the beam and it works in the extensional mode to measure the softness of the contact object. The proposed sensor is modeled both analytically and numerically and a series of simulations are performed in order to estimate the characteristics of the sensor in measuring the magnitude and position of a point load, distributed load, and also the softness of the contact object. Furthermore, in order to validate the theoretical results, the prototyped sensor was tested and the results are compared. The results are very promising and proving the capability of the sensor for haptic sensing.

Tactile sensor is useful for estimating liver hardness and liver fibrosis compared with ultrasonography and computed tomography.

PubMed

Suzuki, Satoshi; Watanabe, Yohei; Yazawa, Takashi; Ishigame, Teruhide; Sassa, Motoki; Monma, Tomoyuki; Takawa, Tadashi; Kumamoto, Kensuke; Nakamura, Izumi; Ohoki, Shinji; Hatakeyama, Yuichi; Sakuma, Hiroshi; Ono, Toshiyuki; Omata, Sadao; Takenoshita, Seiichi

2014-01-01

We examined whether conventional ultrasonography (US) and computed tomography (CT) were useful to evaluate liver hardness and hepatic fibrosis by comparing the results with those obtained by a tactile sensor using rats with liver fibrosis. We used 44 Wistar rats in which liver fibrosis was induced by intraperitoneal administration of thioacetamide. The CT and US values of each liver were measured before laparotomy. After laparotomy, a tactile sensor was used to measure liver hardness. We prepared Azan stained sections of each excised liver specimen and calculated the degree of liver fibrosis (HFI: hepatic fibrosis index) by computed color image analysis. The stiffness values and HFI showed a positive correlation (r=0.690, p<0.001), as did the tactile values and HFI (r=0.709, p<0.001).In addition, the stiffness and tactile values correlated positively with each other (r=0.814, p<0.001). There was no correlation between the CT values and HFI, as well as no correlation between the US values and HFI. We confirmed that it was difficult to evaluate liver hardness and HFI by CT or US examination, and considered that, at present, a tactile sensor is useful method for evaluating HFI.

Bioinspired active whisker sensor for robotic vibrissal tactile sensing

NASA Astrophysics Data System (ADS)

Ju, Feng; Ling, Shih-Fu

2014-12-01

A whisker transducer (WT) inspired by rat’s vibrissal tactile perception is proposed based on a transduction matrix model characterizing the electro-mechanical transduction process in both forward and backward directions. It is capable of acting as an actuator to sweep the whisker and simultaneously as a sensor to sense the force, motion, and mechanical impedance at whisker tip. Its validity is confirmed by numerical simulation using a finite element model. A prototype is then fabricated and its transduction matrix is determined by parameter identification. The calibrated WT can accurately sense mechanical impedance which is directly related to stiffness, mass and damping. Subsequent vibrissal tactile sensing of sandpaper texture reveals that the real part of mechanical impedance sensed by WT is correlated with sandpaper roughness. Texture discrimination is successfully achieved by inputting the real part to a k-means clustering algorithm. The mechanical impedance sensing ability as well as other features of the WT such as simultaneous-actuation-and-sensing makes it a good solution to robotic tactile sensing.

Self-powered, ultra-sensitive, flexible tactile sensors based on contact electrification

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

Wang, Zhong Lin; Zhu, Guang

A tactile sensor for sensing touch from a human finger includes a triboelectric layer and includes a material that becomes electrically charged after being in contact with the finger. The first side of a first conductive layer is in contact with the second side of triboelectric layer. The first side of a dielectric layer is in contact with the first conductive layer and the second side of the dielectric layer is in contact with a second conductive layer. When the triboelectric layer becomes electrically charged after being in contact with the finger, the first conductive layer and the second conductivemore » layer are subjected to an electric field, which has a first field strength at the first conductive layer and a second field strength, different from the first field strength, at the second conductive layer. A plurality of tactile sensors can be arranged as a keyboard.« less

Integrated dynamic and static tactile sensor: focus on static force sensing

NASA Astrophysics Data System (ADS)

Wettels, Nicholas; Pletner, Baruch

2012-04-01

Object grasping by robotic hands in unstructured environments demands a sensor that is durable, compliant, and responsive to static and dynamic force conditions. In order for a tactile sensor to be useful for grasp control in these, it should have the following properties: tri-axial force sensing (two shear plus normal component), dynamic event sensing across slip frequencies, compliant surface for grip, wide dynamic range (depending on application), insensitivity to environmental conditions, ability to withstand abuse and good sensing behavior (e.g. low hysteresis, high repeatability). These features can be combined in a novel multimodal tactile sensor. This sensor combines commercial-off-the-shelf MEMS technology with two proprietary force sensors: a high bandwidth device based on PZT technology and low bandwidth device based on elastomers and optics. In this study, we focus on the latter transduction mechanism and the proposed architecture of the completed device. In this study, an embedded LED was utilized to produce a constant light source throughout a layer of silicon rubber which covered a plastic mandrel containing a set of sensitive phototransistors. Features about the contacted object such as center of pressure and force vectors can be extracted from the information in the changing patterns of light. The voltage versus force relationship obtained with this molded humanlike finger had a wide dynamic range that coincided with forces relevant for most human grip tasks.

Design and analysis of tactile optical sensor for endovascular surgery

NASA Astrophysics Data System (ADS)

Qasaimeh, M. A.; Dargahi, J.; Kahrizi, M.; Packirisamy, M.

2007-06-01

In this paper, design and Finite Element analysis of a new tactile optical sensor for the measurement of contact-pressure and tissue compliance in endovascular surgeries are presented. Using Micro-Electro-Mechanical-Systems (MEMS) technology, this sensor can be fabricated and integrated with the medical tools for endovascular surgeries such as Catheter tool. The designed sensor is capable of detecting the magnitude of the applied forces, the pressure distribution on contact objects, and also estimating the compliance of the contact tissue. The designed sensor is made of three layers, the upper layer is fabricated from monocrystalline silicon to form silicon membranes, the middle layer which is the supporting element is fabricated from both silicon and silicone rubber as a soft material and the lower layer is a supporting Plexiglas substrate to connect the designed sensor to the optical fibers. Simulation results show that for the given contact forces, the magnitude and the distribution of contacting tissues pressure along with tissue compliance can be determined. This sensor as proposed is a good candidate for batch micromachining, which is yet another commercial advantage for this design. Because of its less expensive cost, the surgeon can use it as a disposal part of the endovascular tools, requiring no re-sterilization and reducing the cost of surgery.

Feasibility study of patient motion monitoring by using tactile array sensors

NASA Astrophysics Data System (ADS)

Kim, Tae-Ho; Kang, Seong-Hee; Kim, Dong-Su; Cho, Min-Seok; Kim, Kyeong-Hyeon; Suh, Tae-Suk; Kim, Siyong

2015-07-01

An ideal alignment method based on the external anatomical surface of the patient should consider the entire region of interest. However, optical-camera-based systems cannot blindly monitor such areas as the patient's back, for example. Furthermore, collecting enough information to correct the associated deformation error is impossible. The study aim is to propose a new patient alignment method using tactile array sensors that can measure the distributed pressure profiles along the contact surface. The TactArray system includes one sensor, a signal-conditioning device (USB drive/interface electronics, power supply, and cables), and a PC. The tactile array sensor was placed between the patient's back and the treatment couch, and the deformations at different location on the patient's back were evaluated. Three healthy male volunteers were enrolled in this study, and pressure profile distributions (PPDs) were obtained with and without immobilization. After the initial pretreatment setup using the laser alignment system, the PPD of the patient's back was acquired. The results were obtained at four different times and included a reference PPD dataset. The contact area and the center-of-pressure value were also acquired based on the PPD data for a more elaborate quantitative data analysis. To evaluate the clinical feasibility of using the proposed alignment method for reducing the deformation error, we implemented a real-time self-correction procedure. Despite the initial alignment, we confirmed that PPD variations existed in both cases of the volunteer studies (with and without the use of the immobilization tool). Additionally, we confirmed that the contact area and the center of pressure varied in both cases, and those variations were observed in all three volunteers. With the proposed alignment method and the real-time selfcorrection procedure, the deformation error was significantly reduced. The proposed alignment method can be used to account for the limitation of

Displaying Sensed Tactile Cues with a Fingertip Haptic Device.

PubMed

Pacchierotti, Claudio; Prattichizzo, Domenico; Kuchenbecker, Katherine J

2015-01-01

Telerobotic systems enable humans to explore and manipulate remote environments for applications such as surgery and disaster response, but few such systems provide the operator with cutaneous feedback. This article presents a novel approach to remote cutaneous interaction; our method is compatible with any fingertip tactile sensor and any mechanical tactile display device, and it does not require a position/force or skin deformation model. Instead, it directly maps the sensed stimuli to the best possible input commands for the device's motors using a data set recorded with the tactile sensor inside the device. As a proof of concept, we considered a haptic system composed of a BioTac tactile sensor, in charge of measuring contact deformations, and a custom 3-DoF cutaneous device with a flat contact platform, in charge of applying deformations to the user's fingertip. To validate the proposed approach and discover its inherent tradeoffs, we carried out two remote tactile interaction experiments. The first one evaluated the error between the tactile sensations registered by the BioTac in a remote environment and the sensations created by the cutaneous device for six representative tactile interactions and 27 variations of the display algorithm. The normalized average errors in the best condition were 3.0 percent of the BioTac's full 12-bit scale. The second experiment evaluated human subjects' experiences for the same six remote interactions and eight algorithm variations. The average subjective rating for the best algorithm variation was 8.2 out of 10, where 10 is best.

Influence of Errors in Tactile Sensors on Some High Level Parameters Used for Manipulation with Robotic Hands.

PubMed

Sánchez-Durán, José A; Hidalgo-López, José A; Castellanos-Ramos, Julián; Oballe-Peinado, Óscar; Vidal-Verdú, Fernando

2015-08-19

Tactile sensors suffer from many types of interference and errors like crosstalk, non-linearity, drift or hysteresis, therefore calibration should be carried out to compensate for these deviations. However, this procedure is difficult in sensors mounted on artificial hands for robots or prosthetics for instance, where the sensor usually bends to cover a curved surface. Moreover, the calibration procedure should be repeated often because the correction parameters are easily altered by time and surrounding conditions. Furthermore, this intensive and complex calibration could be less determinant, or at least simpler. This is because manipulation algorithms do not commonly use the whole data set from the tactile image, but only a few parameters such as the moments of the tactile image. These parameters could be changed less by common errors and interferences, or at least their variations could be in the order of those caused by accepted limitations, like reduced spatial resolution. This paper shows results from experiments to support this idea. The experiments are carried out with a high performance commercial sensor as well as with a low-cost error-prone sensor built with a common procedure in robotics.

Single-Grasp Object Classification and Feature Extraction with Simple Robot Hands and Tactile Sensors.

PubMed

Spiers, Adam J; Liarokapis, Minas V; Calli, Berk; Dollar, Aaron M

2016-01-01

Classical robotic approaches to tactile object identification often involve rigid mechanical grippers, dense sensor arrays, and exploratory procedures (EPs). Though EPs are a natural method for humans to acquire object information, evidence also exists for meaningful tactile property inference from brief, non-exploratory motions (a 'haptic glance'). In this work, we implement tactile object identification and feature extraction techniques on data acquired during a single, unplanned grasp with a simple, underactuated robot hand equipped with inexpensive barometric pressure sensors. Our methodology utilizes two cooperating schemes based on an advanced machine learning technique (random forests) and parametric methods that estimate object properties. The available data is limited to actuator positions (one per two link finger) and force sensors values (eight per finger). The schemes are able to work both independently and collaboratively, depending on the task scenario. When collaborating, the results of each method contribute to the other, improving the overall result in a synergistic fashion. Unlike prior work, the proposed approach does not require object exploration, re-grasping, grasp-release, or force modulation and works for arbitrary object start positions and orientations. Due to these factors, the technique may be integrated into practical robotic grasping scenarios without adding time or manipulation overheads.

Optical-to-Tactile Translator

NASA Technical Reports Server (NTRS)

Langevin, Maurice L. (Inventor); Moynihan, Philip I. (Inventor)

2000-01-01

An optical-to-tactile translator provides an aid for the visually impaired by translating a near-field scene to a tactile signal corresponding to said near-field scene. An optical sensor using a plurality of active pixel sensors (APS) converts the optical image within the near-field scene to a digital signal. The digital signal is then processed by a microprocessor and a simple shape signal is generated based on the digital signal. The shape signal is then communicated to a tactile transmitter where the shape signal is converted into a tactile signal using a series of contacts. The shape signal may be an outline of the significant shapes determined in the near-field scene, or the shape signal may comprise a simple symbolic representation of common items encountered repeatedly. The user is thus made aware of the unseen near-field scene, including potential obstacles and dangers, through a series of tactile contacts. In a preferred embodiment, a range determining device such as those commonly found on auto-focusing cameras is included to limit the distance that the optical sensor interprets the near-field scene.

Parametric investigation of scalable tactile sensors

NASA Astrophysics Data System (ADS)

Saadatzi, Mohammad Nasser; Yang, Zhong; Baptist, Joshua R.; Sahasrabuddhe, Ritvij R.; Wijayasinghe, Indika B.; Popa, Dan O.

2017-05-01

In the near future, robots and humans will share the same environment and perform tasks cooperatively. For intuitive, safe, and reliable physical human-robot interaction (pHRI), sensorized robot skins for tactile measurements of contact are necessary. In a previous study, we presented skins consisting of strain gauge arrays encased in silicone encapsulants. Although these structures could measure normal forces applied directly onto the sensing elements, they also exhibited blind spots and response asymmetry to certain loading patterns. This study presents a parametric investigation of piezoresistive polymeric strain gauge that exhibits a symmetric omniaxial response thanks to its novel star-shaped structure. This strain gauge relies on the use of gold micro-patterned star-shaped structures with a thin layer of PEDOT:PSS which is a flexible polymer with piezoresistive properties. In this paper, the sensor is first modeled and comprehensively analyzed in the finite-element simulation environment COMSOL. Simulations include stress-strain loading for a variety of structure parameters such as gauge lengths, widths, and spacing, as well as multiple load locations relative to the gauge. Subsequently, sensors with optimized configurations obtained through simulations were fabricated using cleanroom photolithographic and spin-coating processes, and then experimentally tested. Results show a trend-wise agreement between experiments and simulations.

Fabrication of strain gauge based sensors for tactile skins

NASA Astrophysics Data System (ADS)

Baptist, Joshua R.; Zhang, Ruoshi; Wei, Danming; Saadatzi, Mohammad Nasser; Popa, Dan O.

2017-05-01

Fabricating cost effective, reliable and functional sensors for electronic skins has been a challenging undertaking for the last several decades. Application of such skins include haptic interfaces, robotic manipulation, and physical human-robot interaction. Much of our recent work has focused on producing compliant sensors that can be easily formed around objects to sense normal, tension, or shear forces. Our past designs have involved the use of flexible sensors and interconnects fabricated on Kapton substrates, and piezoresistive inks that are 3D printed using Electro Hydro Dynamic (EHD) jetting onto interdigitated electrode (IDE) structures. However, EHD print heads require a specialized nozzle and the application of a high-voltage electric field; for which, tuning process parameters can be difficult based on the choice of inks and substrates. Therefore, in this paper we explore sensor fabrication techniques using a novel wet lift-off photolithographic technique for patterning the base polymer piezoresistive material, specifically Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) or PEDOT:PSS. Fabricated sensors are electrically and thermally characterized, and temperaturecompensated designs are proposed and validated. Packaging techniques for sensors in polymer encapsulants are proposed and demonstrated to produce a tactile interface device for a robot.

Development of a dual-axis hybrid-type tactile sensor using PET film

NASA Astrophysics Data System (ADS)

Seonggi, Kim; Koo, Ja Choon; Choi, Hyouk Ryeol; Moon, Hyungpil

2013-04-01

In previous work, a dual-axis hybrid-type tactile sensor using PDMS (Polydimethylsiloxane) with a pair of metal electrodes, (which were deposited directly on the PDMS surface), was proposed. The hybrid sensor can measure the normal force and the shear force from the measurement of the change of capacitance and resistance values from the one pair of electrodes. However, the metal is hard to be deposited on the surface of the PDMS because the PDMS is hydrophobic. The hydrophobic surface can be changed to hydrophilic using O2 Plasma treatment or UV treatment. When O2 plasma treatment or UV treatment is used, there is the problem that the processing of the metal deposition and the wiring completed in a very short period of limited time. Also, the deposited metal on the surface of the PDMS is easy to break because the deposited metal is exposed in the air. In this paper, we propose a dual-axis hybrid-type tactile sensor where the PET (polyethylene terephthalate) film is inserted between the PDMS films. The deposited metal is not removed easily from the PET film because the adhesion is strong. Also, the PDMS surrounding the PET film plays the roles of dielectric elastomer and shielding the deposited metal from the external environment at same time. Experimental results verify the effectiveness of the fabricated dual-axis hybrid-type force sensor.

Human skin based triboelectric nanogenerators for harvesting biomechanical energy and as self-powered active tactile sensor system.

PubMed

Yang, Ya; Zhang, Hulin; Lin, Zong-Hong; Zhou, Yu Sheng; Jing, Qingshen; Su, Yuanjie; Yang, Jin; Chen, Jun; Hu, Chenguo; Wang, Zhong Lin

2013-10-22

We report human skin based triboelectric nanogenerators (TENG) that can either harvest biomechanical energy or be utilized as a self-powered tactile sensor system for touch pad technology. We constructed a TENG utilizing the contact/separation between an area of human skin and a polydimethylsiloxane (PDMS) film with a surface of micropyramid structures, which was attached to an ITO electrode that was grounded across a loading resistor. The fabricated TENG delivers an open-circuit voltage up to -1000 V, a short-circuit current density of 8 mA/m(2), and a power density of 500 mW/m(2) on a load of 100 MΩ, which can be used to directly drive tens of green light-emitting diodes. The working mechanism of the TENG is based on the charge transfer between the ITO electrode and ground via modulating the separation distance between the tribo-charged skin patch and PDMS film. Furthermore, the TENG has been used in designing an independently addressed matrix for tracking the location and pressure of human touch. The fabricated matrix has demonstrated its self-powered and high-resolution tactile sensing capabilities by recording the output voltage signals as a mapping figure, where the detection sensitivity of the pressure is about 0.29 ± 0.02 V/kPa and each pixel can have a size of 3 mm × 3 mm. The TENGs may have potential applications in human-machine interfacing, micro/nano-electromechanical systems, and touch pad technology.

Self-Powered High-Resolution and Pressure-Sensitive Triboelectric Sensor Matrix for Real-Time Tactile Mapping.

PubMed

Wang, Xiandi; Zhang, Hanlu; Dong, Lin; Han, Xun; Du, Weiming; Zhai, Junyi; Pan, Caofeng; Wang, Zhong Lin

2016-04-20

A triboelectric sensor matrix (TESM) can accurately track and map 2D tactile sensing. A self-powered, high-resolution, pressure-sensitive, flexible and durable TESM with 16 × 16 pixels is fabricated for the fast detection of single-point and multi-point touching. Using cross-locating technology, a cross-type TESM with 32 × 20 pixels is developed for more rapid tactile mapping, which significantly reduces the addressing lines from m × n to m + n. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

All-Elastomer 3-Axis Contact Resistive Tactile Sensor Arrays and Micromilled Manufacturing Methods Thereof

NASA Technical Reports Server (NTRS)

Penskiy, Ivan (Inventor); Charalambides, Alexandros (Inventor); Bergbreiter, Sarah (Inventor)

2018-01-01

At least one tactile sensor includes an insulating layer and a conductive layer formed on the surface of the insulating layer. The conductive layer defines at least one group of flexible projections extending orthogonally from the surface of the insulating layer. The flexible projections include a major projection extending a distance orthogonally from the surface and at least one minor projection that is adjacent to and separate from the major projection wherein the major projection extends a distance orthogonally that is greater than the distance that the minor projection extends orthogonally. Upon a compressive force normal to, or a shear force parallel to, the surface, the major projection and the minor projection flex such that an electrical contact resistance is formed between the major projection and the minor projection. A capacitive tactile sensor is also disclosed that responds to the normal and shear forces.

A Novel Two-Wire Fast Readout Approach for Suppressing Cable Crosstalk in a Tactile Resistive Sensor Array

PubMed Central

Wu, Jianfeng; Wang, Yu; Li, Jianqing; Song, Aiguo

2016-01-01

For suppressing the crosstalk problem due to wire resistances and contacted resistances of the long flexible cables in tactile sensing systems, we present a novel two-wire fast readout approach for the two-dimensional resistive sensor array in shared row-column fashion. In the approach, two wires are used for every driving electrode and every sampling electrode in the resistive sensor array. The approach with a high readout rate, though it requires a large number of wires and many sampling channels, solves the cable crosstalk problem. We also verified the approach’s performance with Multisim simulations and actual experiments. PMID:27213373

Learning tactile skills through curious exploration

PubMed Central

Pape, Leo; Oddo, Calogero M.; Controzzi, Marco; Cipriani, Christian; Förster, Alexander; Carrozza, Maria C.; Schmidhuber, Jürgen

2012-01-01

We present curiosity-driven, autonomous acquisition of tactile exploratory skills on a biomimetic robot finger equipped with an array of microelectromechanical touch sensors. Instead of building tailored algorithms for solving a specific tactile task, we employ a more general curiosity-driven reinforcement learning approach that autonomously learns a set of motor skills in absence of an explicit teacher signal. In this approach, the acquisition of skills is driven by the information content of the sensory input signals relative to a learner that aims at representing sensory inputs using fewer and fewer computational resources. We show that, from initially random exploration of its environment, the robotic system autonomously develops a small set of basic motor skills that lead to different kinds of tactile input. Next, the system learns how to exploit the learned motor skills to solve supervised texture classification tasks. Our approach demonstrates the feasibility of autonomous acquisition of tactile skills on physical robotic platforms through curiosity-driven reinforcement learning, overcomes typical difficulties of engineered solutions for active tactile exploration and underactuated control, and provides a basis for studying developmental learning through intrinsic motivation in robots. PMID:22837748

Survey of Visual and Force/Tactile Control of Robots for Physical Interaction in Spain

PubMed Central

Garcia, Gabriel J.; Corrales, Juan A.; Pomares, Jorge; Torres, Fernando

2009-01-01

Sensors provide robotic systems with the information required to perceive the changes that happen in unstructured environments and modify their actions accordingly. The robotic controllers which process and analyze this sensory information are usually based on three types of sensors (visual, force/torque and tactile) which identify the most widespread robotic control strategies: visual servoing control, force control and tactile control. This paper presents a detailed review on the sensor architectures, algorithmic techniques and applications which have been developed by Spanish researchers in order to implement these mono-sensor and multi-sensor controllers which combine several sensors. PMID:22303146

Piezoelectric Polymer Tactile Sensor Arrays for Robotics.

DTIC Science & Technology

1987-12-01

response to slow and fast stimuli (Dario and others, 1984:2). The touch receptors relate tactile information through a variety of tactile sensory...flexure. The only occurrence when an evaporated electrode broke (and became intermit - tently open circuited) was during the measurement of the PPTSA *4

Summary of Tactile User Interfaces Techniques and Systems

NASA Technical Reports Server (NTRS)

Spirkovska, Lilly

2005-01-01

Mental workload can be de.ned as the ratio of demand to allocated resources. Multiple-resource theory stresses the importance of distribution of tasks and information across various human sensory channels to reduce mental workload. One sensory channel that has been of interest since the late 1800s is touch. Unlike the more typical displays that target vision or hearing, tactile displays present information to the user s sense of touch. We present a summary of different methods for tactile display, historic and more recent systems that incorporate tactile display for information presentation, advantages and disadvantages of targeting the tactile channel, and future directions in tactile display research.

Summary of Tactile User Interfaces Techniques and Systems

NASA Technical Reports Server (NTRS)

Spirkovska, Lilly

2004-01-01

Mental workload can be defined as the ratio of demand to allocated resources. Multiple- resource theory stresses the importance of distribution of tasks and information across various sensory channels of the human to reduce mental workload. One sensory channel that has been of interest since the late 1800s is touch. Unlike the more typical displays that target vision or hearing, tactile displays present information to the user s sense of touch. We present a summary of different methods for tactile display; historic and more recent systems that incorporate tactile display for information presentation; advantages and disadvantages of targeting the tactile channel; and future directions in tactile display research.

Spider-web inspired multi-resolution graphene tactile sensor.

PubMed

Liu, Lu; Huang, Yu; Li, Fengyu; Ma, Ying; Li, Wenbo; Su, Meng; Qian, Xin; Ren, Wanjie; Tang, Kanglai; Song, Yanlin

2018-05-08

Multi-dimensional accurate response and smooth signal transmission are critical challenges in the advancement of multi-resolution recognition and complex environment analysis. Inspired by the structure-activity relationship between discrepant microstructures of the spiral and radial threads in a spider web, we designed and printed graphene with porous and densely-packed microstructures to integrate into a multi-resolution graphene tactile sensor. The three-dimensional (3D) porous graphene structure performs multi-dimensional deformation responses. The laminar densely-packed graphene structure contributes excellent conductivity with flexible stability. The spider-web inspired printed pattern inherits orientational and locational kinesis tracking. The multi-structure construction with homo-graphene material can integrate discrepant electronic properties with remarkable flexibility, which will attract enormous attention for electronic skin, wearable devices and human-machine interactions.

Driving Interface Based on Tactile Sensors for Electric Wheelchairs or Trolleys

PubMed Central

Trujillo-León, Andrés; Vidal-Verdú, Fernando

2014-01-01

This paper introduces a novel device based on a tactile interface to replace the attendant joystick in electric wheelchairs. It can also be used in other vehicles such as shopping trolleys. Its use allows intuitive driving that requires little or no training, so its usability is high. This is achieved by a tactile sensor located on the handlebar of the chair or trolley and the processing of the information provided by it. When the user interacts with the handle of the chair or trolley, he or she exerts a pressure pattern that depends on the intention to accelerate, brake or turn to the left or right. The electronics within the device then perform the signal conditioning and processing of the information received, identifying the intention of the user on the basis of this pattern using an algorithm, and translating it into control signals for the control module of the wheelchair. These signals are equivalent to those provided by a joystick. This proposal aims to help disabled people and their attendees and prolong the personal autonomy in a context of aging populations. PMID:24518892

A two-ply polymer-based flexible tactile sensor sheet using electric capacitance.

PubMed

Guo, Shijie; Shiraoka, Takahisa; Inada, Seisho; Mukai, Toshiharu

2014-01-29

Traditional capacitive tactile sensor sheets usually have a three-layered structure, with a dielectric layer sandwiched by two electrode layers. Each electrode layer has a number of parallel ribbon-like electrodes. The electrodes on the two electrode layers are oriented orthogonally and each crossing point of the two perpendicular electrode arrays makes up a capacitive sensor cell on the sheet. It is well known that compatibility between measuring precision and resolution is difficult, since decreasing the width of the electrodes is required to obtain a high resolution, however, this may lead to reduction of the area of the sensor cells, and as a result, lead to a low Signal/Noise (S/N) ratio. To overcome this problem, a new multilayered structure and related calculation procedure are proposed. This new structure stacks two or more sensor sheets with shifts in position. Both a high precision and a high resolution can be obtained by combining the signals of the stacked sensor sheets. Trial production was made and the effect was confirmed.

Capacitive wearable tactile sensor based on smart textile substrate with carbon black /silicone rubber composite dielectric

NASA Astrophysics Data System (ADS)

Guo, Xiaohui; Huang, Ying; Cai, Xia; Liu, Caixia; Liu, Ping

2016-04-01

To achieve the wearable comfort of electronic skin (e-skin), a capacitive sensor printed on a flexible textile substrate with a carbon black (CB)/silicone rubber (SR) composite dielectric was demonstrated in this paper. Organo-silicone conductive silver adhesive serves as a flexible electrodes/shielding layer. The structure design, sensing mechanism and the influence of the conductive filler content and temperature variations on the sensor performance were investigated. The proposed device can effectively enhance the flexibility and comfort of wearing the device asthe sensing element has achieved a sensitivity of 0.02536%/KPa, a hysteresis error of 5.6%, and a dynamic response time of ~89 ms at the range of 0-700 KPa. The drift induced by temperature variations has been calibrated by presenting the temperature compensation model. The research on the time-space distribution of plantar pressure information and the experiment of the manipulator soft-grasping were implemented with the introduced device, and the experimental results indicate that the capacitive flexible textile tactile sensor has good stability and tactile perception capacity. This study provides a good candidate for wearable artificial skin.

Neuromimetic Event-Based Detection for Closed-Loop Tactile Feedback Control of Upper Limb Prostheses

PubMed Central

Osborn, Luke; Kaliki, Rahul; Soares, Alcimar; Thakor, Nitish

2016-01-01

Upper limb amputees lack the valuable tactile sensing that helps provide context about the surrounding environment. Here we utilize tactile information to provide active touch feedback to a prosthetic hand. First, we developed fingertip tactile sensors for producing biomimetic spiking responses for monitoring contact, release, and slip of an object grasped by a prosthetic hand. We convert the sensor output into pulses, mimicking the rapid and slowly adapting spiking responses of receptor afferents found in the human body. Second, we designed and implemented two neuromimetic event-based algorithms, Compliant Grasping and Slip Prevention, on a prosthesis to create a local closed-loop tactile feedback control system (i.e. tactile information is sent to the prosthesis). Grasping experiments were designed to assess the benefit of this biologically inspired neuromimetic tactile feedback to a prosthesis. Results from able-bodied and amputee subjects show the average number of objects that broke or slipped during grasping decreased by over 50% and the average time to complete a grasping task decreased by at least 10% for most trials when comparing neuromimetic tactile feedback with no feedback on a prosthesis. Our neuromimetic method of closed-loop tactile sensing is a novel approach to improving the function of upper limb prostheses. PMID:27777640

Market study: Tactile paging system

NASA Technical Reports Server (NTRS)

1977-01-01

A market survey was conducted regarding the commercialization potential and key market factors relevant to a tactile paging system for deaf-blind people. The purpose of the tactile paging system is to communicate to the deaf-blind people in an institutional environment. The system consists of a main console and individual satellite wrist units. The console emits three signals by telemetry to the wrist com (receiving unit) which will measure approximately 2 x 4 x 3/4 inches and will be fastened to the wrist by a strap. The three vibration signals are fire alarm, time period indication, and a third signal which will alert the wearer of the wrist com to the fact that the pin on the top of the wrist is emitting a morse coded message. The Morse code message can be felt and recognized with the finger.

Object Imaging Accomplished with an Integrated Circuit Robotic Tactile Sensor Incorporating a Piezoelectric Polyvinylidene Fluoride Thin Film

DTIC Science & Technology

1993-12-01

sensor response. That is, the tactile sensor’s response to a temperature change could be interpreted as the sensor’s response solely to an externally...is a vector quantity. A force acting on a surface can be interpreted in terms of a normal and a tangential component. Often, these components are...polarization [12]: 3-16 h K" + (3.34) Similarly, the stress in a material due to an applied strain and polarization is [12]: T = cS- hTP (3.35) The electric

Multifunctional Woven Structure Operating as Triboelectric Energy Harvester, Capacitive Tactile Sensor Array, and Piezoresistive Strain Sensor Array

PubMed Central

Kim, Kihong; Song, Giyoung; Park, Cheolmin; Yun, Kwang-Seok

2017-01-01

This paper presents a power-generating sensor array in a flexible and stretchable form. The proposed device is composed of resistive strain sensors, capacitive tactile sensors, and a triboelectric energy harvester in a single platform. The device is implemented in a woven textile structure by using proposed functional threads. A single functional thread is composed of a flexible hollow tube coated with silver nanowires on the outer surface and a conductive silver thread inside the tube. The total size of the device is 60 × 60 mm2 having a 5 × 5 array of sensor cell. The touch force in the vertical direction can be sensed by measuring the capacitance between the warp and weft functional threads. In addition, because silver nanowire layers provide piezoresistivity, the strain applied in the lateral direction can be detected by measuring the resistance of each thread. Last, with regard to the energy harvester, the maximum power and power density were measured as 201 μW and 0.48 W/m2, respectively, when the device was pushed in the vertical direction. PMID:29120363

Modeling Analysis of a Six-axis Force/Tactile Sensor for Robot Fingers and a Method for Decreasing Error

NASA Astrophysics Data System (ADS)

Luo, Minghua; Shimizu, Etsuro; Zhang, Feifei; Ito, Masanori

This paper describes a six-axis force/tactile sensor for robot fingers. A mathematical model of this sensor is proposed. By this model, the grasping force and its moments, and touching position of robot finger for holding an object can be calculated. A new sensor is fabricated based on this model, where the elastic sensing unit of the sensor is made of a brazen plate. A new compensating method for decreasing error is proposed. Furthermore, the performance of this sensor is examined. The test results present approximate relationship between theoretical input and output of the sensor. It is obvious that the performance of the new sensor is better than the sensor with no compensation.

Prototype tactile feedback system for examination by skin touch.

PubMed

Lee, O; Lee, K; Oh, C; Kim, K; Kim, M

2014-08-01

Diagnosis of conditions such as psoriasis and atopic dermatitis, in the case of induration, involves palpating the infected area via hands and then selecting a ratings score. However, the score is determined based on the tester's experience and standards, making it subjective. To provide tactile feedback on the skin, we developed a prototype tactile feedback system to simulate skin wrinkles with PHANToM OMNI. To provide the user with tactile feedback on skin wrinkles, a visual and haptic Augmented Reality system was developed. First, a pair of stereo skin images obtained by a stereo camera generates a disparity map of skin wrinkles. Second, the generated disparity map is sent to an implemented tactile rendering algorithm that computes a reaction force according to the user's interaction with the skin image. We first obtained a stereo image of skin wrinkles from the in vivo stereo imaging system, which has a baseline of 50.8 μm, and obtained the disparity map with a graph cuts algorithm. The left image is displayed on the monitor to enable the user to recognize the location visually. The disparity map of the skin wrinkle image sends skin wrinkle information as a tactile response to the user through a haptic device. We successfully developed a tactile feedback system for virtual skin wrinkle simulation by means of a commercialized haptic device that provides the user with a single point of contact to feel the surface roughness of a virtual skin sample. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A Tactile Sensor Using Piezoresistive Beams for Detection of the Coefficient of Static Friction

PubMed Central

Okatani, Taiyu; Takahashi, Hidetoshi; Noda, Kentaro; Takahata, Tomoyuki; Matsumoto, Kiyoshi; Shimoyama, Isao

2016-01-01

This paper reports on a tactile sensor using piezoresistive beams for detection of the coefficient of static friction merely by pressing the sensor against an object. The sensor chip is composed of three pairs of piezoresistive beams arranged in parallel and embedded in an elastomer; this sensor is able to measure the vertical and lateral strains of the elastomer. The coefficient of static friction is estimated from the ratio of the fractional resistance changes corresponding to the sensing elements of vertical and lateral strains when the sensor is in contact with an object surface. We applied a normal force on the sensor surface through objects with coefficients of static friction ranging from 0.2 to 1.1. The fractional resistance changes corresponding to vertical and lateral strains were proportional to the applied force. Furthermore, the relationship between these responses changed according to the coefficients of static friction. The experimental result indicated the proposed sensor could determine the coefficient of static friction before a global slip occurs. PMID:27213374

Tactile-Sensing Based on Flexible PVDF Nanofibers via Electrospinning: A Review

PubMed Central

Wang, Xiaomei; Sun, Fazhe; Yin, Guangchao; Wang, Yuting; Liu, Bo

2018-01-01

The flexible tactile sensor has attracted widespread attention because of its great flexibility, high sensitivity, and large workable range. It can be integrated into clothing, electronic skin, or mounted on to human skin. Various nanostructured materials and nanocomposites with high flexibility and electrical performance have been widely utilized as functional materials in flexible tactile sensors. Polymer nanomaterials, representing the most promising materials, especially polyvinylidene fluoride (PVDF), PVDF co-polymer and their nanocomposites with ultra-sensitivity, high deformability, outstanding chemical resistance, high thermal stability and low permittivity, can meet the flexibility requirements for dynamic tactile sensing in wearable electronics. Electrospinning has been recognized as an excellent straightforward and versatile technique for preparing nanofiber materials. This review will present a brief overview of the recent advances in PVDF nanofibers by electrospinning for flexible tactile sensor applications. PVDF, PVDF co-polymers and their nanocomposites have been successfully formed as ultrafine nanofibers, even as randomly oriented PVDF nanofibers by electrospinning. These nanofibers used as the functional layers in flexible tactile sensors have been reviewed briefly in this paper. The β-phase content, which is the strongest polar moment contributing to piezoelectric properties among all the crystalline phases of PVDF, can be improved by adjusting the technical parameters in electrospun PVDF process. The piezoelectric properties and the sensibility for the pressure sensor are improved greatly when the PVDF fibers become more oriented. The tactile performance of PVDF composite nanofibers can be further promoted by doping with nanofillers and nanoclay. Electrospun P(VDF-TrFE) nanofiber mats used for the 3D pressure sensor achieved excellent sensitivity, even at 0.1 Pa. The most significant enhancement is that the aligned electrospun core-shell P

Hybrid piezoresistive-optical tactile sensor for simultaneous measurement of tissue stiffness and detection of tissue discontinuity in robot-assisted minimally invasive surgery

NASA Astrophysics Data System (ADS)

Bandari, Naghmeh M.; Ahmadi, Roozbeh; Hooshiar, Amir; Dargahi, Javad; Packirisamy, Muthukumaran

2017-07-01

To compensate for the lack of touch during minimally invasive and robotic surgeries, tactile sensors are integrated with surgical instruments. Surgical tools with tactile sensors have been used mainly for distinguishing among different tissues and detecting malignant tissues or tumors. Studies have revealed that malignant tissue is most likely stiffer than normal. This would lead to the formation of a sharp discontinuity in tissue mechanical properties. A hybrid piezoresistive-optical-fiber sensor is proposed. This sensor is investigated for its capabilities in tissue distinction and detection of a sharp discontinuity. The dynamic interaction of the sensor and tissue is studied using finite element method. The tissue is modeled as a two-term Mooney-Rivlin hyperelastic material. For experimental verification, the sensor was microfabricated and tested under the same conditions as of the simulations. The simulation and experimental results are in a fair agreement. The sensor exhibits an acceptable linearity, repeatability, and sensitivity in characterizing the stiffness of different tissue phantoms. Also, it is capable of locating the position of a sharp discontinuity in the tissue. Due to the simplicity of its sensing principle, the proposed hybrid sensor could also be used for industrial applications.

Sensitivity improvements of a resonance-based tactile sensor.

PubMed

Murayama, Yoshinobu; Lindahl, Olof A

2017-02-01

Resonance-based contact-impedance measurement refers to the application of resonance sensors based on the measurement of the changes in the resonance curve of an ultrasonic resonator in contact with a surface. The advantage of the resonance sensor is that it is very sensitive to small changes in the contact impedance. A sensitive micro tactile sensor (MTS) was developed, which measured the elasticity of soft living tissues at the single-cell level. In the present paper, we studied the method of improving the touch and stiffness sensitivity of the MTS. First, the dependence of touch sensitivity in relation to the resonator length was studied by calculating the sensitivity coefficient at each length ranging from 9 to 40 mm. The highest touch sensitivity was obtained with a 30-mm-long glass needle driven at a resonance frequency of 100 kHz. Next, the numerical calculation of contact impedance showed that the highest stiffness sensitivity was achieved when the driving frequency was 100 kHz and the contact-tip diameter of the MTS was 10 μm. The theoretical model was then confirmed experimentally using a phase-locked-loop-based digital feedback oscillation circuit. It was found that the developed MTS, whose resonant frequency was 97.030 kHz, performed with the highest sensitivity of 53.2 × 10 6  Hz/N at the driving frequency of 97.986 kHz, i.e. the highest sensitivity was achieved at 956 Hz above the resonant frequency.

Sensing Senses: Tactile Feedback for the Prevention of Decubitus Ulcers

PubMed Central

Verbunt, Marcel

2009-01-01

Decubitus ulcers, also known as pressure sores, is a major problem in health care, in particular for patients with spinal cord injuries. These patients cannot feel the discomfort that would urge healthy people to change their posture. We describe a system that uses a sensor mat to detect problematic postures and provides tactile feedback to the user. The results of our preliminary study with healthy subjects show that the tactile feedback is a viable option to spoken feedback. We envision the system being used for rehabilitation games, but also for everyday Decubitus ulcers prevention. PMID:19949852

Design and finite element modeling of a novel optical microsystems-based tactile sensor for minimal invasive robotic surgery

NASA Astrophysics Data System (ADS)

Ghanbari Mardasi, Amir; Ghanbari, Mahmood; Salmani Tehrani, Mehdi

2014-09-01

Although recently Minimal Invasive Robotic Surgery (MIRS) has been more addressed because of its wide range of benefits, however there are still some limitations in this regard. In order to address the shortcomings of MIRS systems, various types of tactile sensors with different sensing principles have been presented in the last few years. In the present paper a MEMS-based optical sensor, which has been recently proposed by researchers, is investigated using numerical simulation. By this type of sensors real time quantification of both dynamic and statics contact forces between the tissue and surgical instrument would be possible. The presented sensor has one moving part and works based on the intensity modulation principle of optical fibers. It is electrically-passive, MRI-compatible and it is possible to be fabricated using available standard micro fabrication techniques. The behavior of the sensor has been simulated using COMSOL MULTIPHYSICS 3.5 software. Stress analysis is conducted on the sensor to assess the deflection of the moving part of the sensor due to applied force. The optical simulation is then conducted to estimate the power loss due to the moving part deflection. Using FEM modeling, the relation between force and deflection is derived which is necessary for the calibration of the sensor.

Biologically inspired multi-layered synthetic skin for tactile feedback in prosthetic limbs.

PubMed

Osborn, Luke; Nguyen, Harrison; Betthauser, Joseph; Kaliki, Rahul; Thakor, Nitish

2016-08-01

The human body offers a template for many state-of-the-art prosthetic devices and sensors. In this work, we present a novel, sensorized synthetic skin that mimics the natural multi-layered nature of mechanoreceptors found in healthy glabrous skin to provide tactile information. The multi-layered sensor is made up of flexible piezoresistive textiles that act as force sensitive resistors (FSRs) to convey tactile information, which are embedded within a silicone rubber to resemble the compliant nature of human skin. The top layer of the synthetic skin is capable of detecting small loads less than 5 N whereas the bottom sensing layer responds reliably to loads over 7 N. Finite element analysis (FEA) of a simplified human fingertip and the synthetic skin was performed. Results suggest similarities in behavior during loading. A natural tactile event is simulated by loading the synthetic skin on a prosthetic limb. Results show the sensors' ability to detect applied loads as well as the ability to simulate neural spiking activity based on the derivative and temporal differences of the sensor response. During the tactile loading, the top sensing layer responded 0.24 s faster than the bottom sensing layer. A synthetic biologically-inspired skin such as this will be useful for enhancing the functionality of prosthetic limbs through tactile feedback.

Tooteko: a Case Study of Augmented Reality for AN Accessible Cultural Heritage. Digitization, 3d Printing and Sensors for AN Audio-Tactile Experience

NASA Astrophysics Data System (ADS)

D'Agnano, F.; Balletti, C.; Guerra, F.; Vernier, P.

2015-02-01

Tooteko is a smart ring that allows to navigate any 3D surface with your finger tips and get in return an audio content that is relevant in relation to the part of the surface you are touching in that moment. Tooteko can be applied to any tactile surface, object or sheet. However, in a more specific domain, it wants to make traditional art venues accessible to the blind, while providing support to the reading of the work for all through the recovery of the tactile dimension in order to facilitate the experience of contact with art that is not only "under glass." The system is made of three elements: a high-tech ring, a tactile surface tagged with NFC sensors, and an app for tablet or smartphone. The ring detects and reads the NFC tags and, thanks to the Tooteko app, communicates in wireless mode with the smart device. During the tactile navigation of the surface, when the finger reaches a hotspot, the ring identifies the NFC tag and activates, through the app, the audio track that is related to that specific hotspot. Thus a relevant audio content relates to each hotspot. The production process of the tactile surfaces involves scanning, digitization of data and 3D printing. The first experiment was modelled on the facade of the church of San Michele in Isola, made by Mauro Codussi in the late fifteenth century, and which marks the beginning of the Renaissance in Venice. Due to the absence of recent documentation on the church, the Correr Museum asked the Laboratorio di Fotogrammetria to provide it with the aim of setting up an exhibition about the order of the Camaldolesi, owners of the San Michele island and church. The Laboratorio has made the survey of the facade through laser scanning and UAV photogrammetry. The point clouds were the starting point for prototypation and 3D printing on different supports. The idea of the integration between a 3D printed tactile surface and sensors was born as a final thesis project at the Postgraduate Mastercourse in Digital

Tactile device utilizing a single magnetorheological sponge: experimental investigation

NASA Astrophysics Data System (ADS)

Kim, Soomin; Kim, Pyunghwa; Choi, Seung-Hyun; Oh, Jong-Seok; Choi, Seung-Bok

2015-04-01

In the field of medicine, several new areas have been currently introduced such as robot-assisted surgery. However, the major drawback of these systems is that there is no tactile communication between doctors and surgical sites. When the tactile system is brought up, telemedicine including telerobotic surgery can be enhanced much more than now. In this study, a new tactile device is designed using a single magnetorhological (MR) sponge cell to realize the sensation of human organs. MR fluids and an open celled polyurethane foam are used to propose the MR sponge cell. The viscous and elastic sensational behaviors of human organs are realized by the MR sponge cell. Before developing the tactile device, tactile sensation according to touch of human fingers are quantified in advance. The finger is then treated as a reduced beam bundle model (BBM) in which the fingertip is comprised of an elastic beam virtually. Under the reduced BBM, when people want to sense an object, the fingertip is investigated by pushing and sliding. Accordingly, while several magnitudes of magnetic fields are applied to the tactile device, normal and tangential reaction forces and bending moment are measured by 6-axis force/torque sensor instead of the fingertip. These measured data are used to compare with soft tissues. It is demonstrated that the proposed MR sponge cell can realize any part of the organ based on the obtained data.

Spatial asymmetry in tactile sensor skin deformation aids perception of edge orientation during haptic exploration.

PubMed

Ponce Wong, Ruben D; Hellman, Randall B; Santos, Veronica J

2014-01-01

Upper-limb amputees rely primarily on visual feedback when using their prostheses to interact with others or objects in their environment. A constant reliance upon visual feedback can be mentally exhausting and does not suffice for many activities when line-of-sight is unavailable. Upper-limb amputees could greatly benefit from the ability to perceive edges, one of the most salient features of 3D shape, through touch alone. We present an approach for estimating edge orientation with respect to an artificial fingertip through haptic exploration using a multimodal tactile sensor on a robot hand. Key parameters from the tactile signals for each of four exploratory procedures were used as inputs to a support vector regression model. Edge orientation angles ranging from -90 to 90 degrees were estimated with an 85-input model having an R (2) of 0.99 and RMS error of 5.08 degrees. Electrode impedance signals provided the most useful inputs by encoding spatially asymmetric skin deformation across the entire fingertip. Interestingly, sensor regions that were not in direct contact with the stimulus provided particularly useful information. Methods described here could pave the way for semi-autonomous capabilities in prosthetic or robotic hands during haptic exploration, especially when visual feedback is unavailable.

A droplet-based passive force sensor for remote tactile sensing applications

NASA Astrophysics Data System (ADS)

Nie, Baoqing; Yao, Ting; Zhang, Yiqiu; Liu, Jian; Chen, Xinjian

2018-01-01

A droplet-based flexible wireless force sensor has been developed for remote tactile-sensing applications. By integration of a droplet-based capacitive sensing unit and two circular planar coils, this inductor-capacitor (LC) passive sensor offers a platform for the mechanical force detection in a wireless transmitting mode. Under external loads, the membrane surface of the sensor deforms the underlying elastic droplet uniformly, introducing a capacitance response in tens of picofarads. The LC circuit transduces the applied force into corresponding variations of its resonance frequency, which is detected by an external electromagnetic coupling coil. Specifically, the liquid droplet features a mechanosensitive plasticity, which results in an increased device sensitivity as high as 2.72 MHz N-1. The high dielectric property of the droplet endows our sensor with high tolerance for noise and large capacitance values (20-40 pF), the highest value in the literature for the LC passive devices in comparable dimensions. It achieves excellent reproducibility under periodical loads ranging from 0 to 1.56 N and temperature fluctuations ranging from 10 °C to 55 °C. As an interesting conceptual demonstration, the flexible device has been configured into a fingertip-amounted setting in a highly compact package (of 11 mm × 11 mm × 0.25 mm) for remote contact force sensing in the table tennis game.

3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer.

PubMed

Asano, Sho; Muroyama, Masanori; Nakayama, Takahiro; Hata, Yoshiyuki; Nonomura, Yutaka; Tanaka, Shuji

2017-10-25

This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D)-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively.

Development of haptic based piezoresistive artificial fingertip: Toward efficient tactile sensing systems for humanoids.

PubMed

TermehYousefi, Amin; Azhari, Saman; Khajeh, Amin; Hamidon, Mohd Nizar; Tanaka, Hirofumi

2017-08-01

Haptic sensors are essential devices that facilitate human-like sensing systems such as implantable medical devices and humanoid robots. The availability of conducting thin films with haptic properties could lead to the development of tactile sensing systems that stretch reversibly, sense pressure (not just touch), and integrate with collapsible. In this study, a nanocomposite based hemispherical artificial fingertip fabricated to enhance the tactile sensing systems of humanoid robots. To validate the hypothesis, proposed method was used in the robot-like finger system to classify the ripe and unripe tomato by recording the metabolic growth of the tomato as a function of resistivity change during a controlled indention force. Prior to fabrication, a finite element modeling (FEM) was investigated for tomato to obtain the stress distribution and failure point of tomato by applying different external loads. Then, the extracted computational analysis information was utilized to design and fabricate nanocomposite based artificial fingertip to examine the maturity analysis of tomato. The obtained results demonstrate that the fabricated conformable and scalable artificial fingertip shows different electrical property for ripe and unripe tomato. The artificial fingertip is compatible with the development of brain-like systems for artificial skin by obtaining periodic response during an applied load. Copyright © 2017. Published by Elsevier B.V.

Object Recognition and Localization: The Role of Tactile Sensors

PubMed Central

Aggarwal, Achint; Kirchner, Frank

2014-01-01

Tactile sensors, because of their intrinsic insensitivity to lighting conditions and water turbidity, provide promising opportunities for augmenting the capabilities of vision sensors in applications involving object recognition and localization. This paper presents two approaches for haptic object recognition and localization for ground and underwater environments. The first approach called Batch Ransac and Iterative Closest Point augmented Particle Filter (BRICPPF) is based on an innovative combination of particle filters, Iterative-Closest-Point algorithm, and a feature-based Random Sampling and Consensus (RANSAC) algorithm for database matching. It can handle a large database of 3D-objects of complex shapes and performs a complete six-degree-of-freedom localization of static objects. The algorithms are validated by experimentation in ground and underwater environments using real hardware. To our knowledge this is the first instance of haptic object recognition and localization in underwater environments. The second approach is biologically inspired, and provides a close integration between exploration and recognition. An edge following exploration strategy is developed that receives feedback from the current state of recognition. A recognition by parts approach is developed which uses the BRICPPF for object sub-part recognition. Object exploration is either directed to explore a part until it is successfully recognized, or is directed towards new parts to endorse the current recognition belief. This approach is validated by simulation experiments. PMID:24553087

Nano opto-mechanical systems (NOMS) as a proposal for tactile displays

NASA Astrophysics Data System (ADS)

Campo, E. M.; Roig, J.; Roeder, B.; Wenn, D.; Mamojka, B.; Omastova, M.; Terentjev, E. M.; Esteve, J.

2011-10-01

For over a decade, special emphasis has been placed in the convergence of different fields of science and technology, in an effort to serve human needs by way of enhancing human capabilities. The convergence of the Nano-Bio-Info-Cogni (NBIC) quartet will provide unique solutions to specific needs. This is the case of, Nano-opto mechanical Systems (NOMS), presented as a solution to tactile perception, both for the visually-impaired and for the general public. NOMS, based on photoactive polymer actuators and devices, is a much sought-after technology. In this scheme, light sources promote mechanical actuation producing a variety of nano-opto mechanical systems such as nano-grippers. In this paper, we will provide a series of specifications that the NOMS team is targeting towards the development of a tactile display using optically-activated smart materials. Indeed, tactile displays remain mainly mechanical, compromising reload speeds and resolution which inhibit 3D tactile representation of web interfaces. We will also discuss how advantageous NOMS tactile displays could be for the general public. Tactile processing based on stimulation delivered through the NOMS tablet, will be tested using neuropsychology methods, in particular event-related brain potentials. Additionally, the NOMS tablet will be instrumental to the development of basic neuroscience research.

Research on pressure tactile sensing technology based on fiber Bragg grating array

NASA Astrophysics Data System (ADS)

Song, Jinxue; Jiang, Qi; Huang, Yuanyang; Li, Yibin; Jia, Yuxi; Rong, Xuewen; Song, Rui; Liu, Hongbin

2015-09-01

A pressure tactile sensor based on the fiber Bragg grating (FBG) array is introduced in this paper, and the numerical simulation of its elastic body was implemented by finite element software (ANSYS). On the basis of simulation, fiber Bragg grating strings were implanted in flexible silicone to realize the sensor fabrication process, and a testing system was built. A series of calibration tests were done via the high precision universal press machine. The tactile sensor array perceived external pressure, which is demodulated by the fiber grating demodulation instrument, and three-dimension pictures were programmed to display visually the position and size. At the same time, a dynamic contact experiment of the sensor was conducted for simulating robot encountering other objects in the unknown environment. The experimental results show that the sensor has good linearity, repeatability, and has the good effect of dynamic response, and its pressure sensitivity was 0.03 nm/N. In addition, the sensor also has advantages of anti-electromagnetic interference, good flexibility, simple structure, low cost and so on, which is expected to be used in the wearable artificial skin in the future.

Durable Tactile Glove for Human or Robot Hand

NASA Technical Reports Server (NTRS)

Butzer, Melissa; Diftler, Myron A.; Huber, Eric

2010-01-01

A glove containing force sensors has been built as a prototype of tactile sensor arrays to be worn on human hands and anthropomorphic robot hands. The force sensors of this glove are mounted inside, in protective pockets; as a result of this and other design features, the present glove is more durable than earlier models.

Artery cross-clamping during laparoscopic vascular surgeries; a computational tactile sensing approach.

PubMed

Pahlavan, Pedram; Najarian, Siamak; Afshari, Elnaz; Moini, Majid

2013-01-01

Artificial palpation is one of the most valuable achievements of artificial tactile sensing approach that can be used in various fields of medicine and more specifically in surgery. These techniques cause different surgical maneuvers to be done more precisely and noninvasively. In this study, considering the present problems and limitations of cross-clamping an artery during laparoscopic vascular surgeries, a new tactile sensory system will be introduced.Having imitated surgeon's palpation during open vascular surgeries and modeled it conceptually, the optimal amount of the total angular displacement of each robot joint in order to cross-clamping an artery without damaging to the artery surrounding tissues will be calculated. The elastic governing equation of contact occurred between the tactile sensor placed on the first link of the robot and the surrounding tissues around the artery were developed. A finite element model is coupled with genetic algorithm optimization method so that the normal stress and displacements in contact surface of the robot and artery's surrounding tissues would be minimized. Thus, reliability and accuracy of artificial tactile sensing method in artery cross-clamping will be demonstrated. Finally, the functional principles of the new tactile system capable of cross-clamping an artery during laparoscopic surgeries will be presented.

A CMOS micromachined capacitive tactile sensor with integrated readout circuits and compensation of process variations.

PubMed

Tsai, Tsung-Heng; Tsai, Hao-Cheng; Wu, Tien-Keng

2014-10-01

This paper presents a capacitive tactile sensor fabricated in a standard CMOS process. Both of the sensor and readout circuits are integrated on a single chip by a TSMC 0.35 μm CMOS MEMS technology. In order to improve the sensitivity, a T-shaped protrusion is proposed and implemented. This sensor comprises the metal layer and the dielectric layer without extra thin film deposition, and can be completed with few post-processing steps. By a nano-indenter, the measured spring constant of the T-shaped structure is 2.19 kNewton/m. Fully differential correlated double sampling capacitor-to-voltage converter (CDS-CVC) and reference capacitor correction are utilized to compensate process variations and improve the accuracy of the readout circuits. The measured displacement-to-voltage transductance is 7.15 mV/nm, and the sensitivity is 3.26 mV/μNewton. The overall power dissipation is 132.8 μW.

A Sensitivity Enhanced MWCNT/PDMS Tactile Sensor Using Micropillars and Low Energy Ar⁺ Ion Beam Treatment.

PubMed

Azkar Ul Hasan, Syed; Jung, Youngdo; Kim, Seonggi; Jung, Cho-Long; Oh, Sunjong; Kim, Junhee; Lim, Hyuneui

2016-01-12

High sensitive flexible and wearable devices which can detect delicate touches have attracted considerable attentions from researchers for various promising applications. This research was aimed at enhancing the sensitivity of a MWCNT/PDMS piezoresistive tactile sensor through modification of its surface texture in the form of micropillars on MWCNT/PDMS film and subsequent low energy Ar⁺ ion beam treatment of the micropillars. The introduction of straight micropillars on the MWCNT/PDMS surface increased the sensitivity under gentle touch. Low energy ion beam treatment was performed to induce a stiff layer on the exposed surface of the micropillar structured MWCNT/PDMS film. The low energy ion bombardment stabilized the electrical properties of the MWCNT/PDMS surface and tuned the curvature of micropillars according to the treatment conditions. The straight micropillars which were treated by Ar⁺ ion with an incident angle of 0° demonstrated the enhanced sensitivity under normal pressure and the curved micropillars which were treated with Ar⁺ ion with an incident angle of 60° differentiated the direction of an applied shear pressure. The ion beam treatment on micropillar structured MWCNT/PDMS tactile sensors can thus be applied to reliable sensing under gentle touch with directional discrimination.

Use of tactile feedback to control exploratory movements to characterize object compliance.

PubMed

Su, Zhe; Fishel, Jeremy A; Yamamoto, Tomonori; Loeb, Gerald E

2012-01-01

Humans have been shown to be good at using active touch to perceive subtle differences in compliance. They tend to use highly stereotypical exploratory strategies, such as applying normal force to a surface. We developed similar exploratory and perceptual algorithms for a mechatronic robotic system (Barrett arm/hand system) equipped with liquid-filled, biomimetic tactile sensors (BioTac(®) from SynTouch LLC). The distribution of force on the fingertip was measured by the electrical resistance of the conductive liquid trapped between the elastomeric skin and a cluster of four electrodes on the flat fingertip surface of the rigid core of the BioTac. These signals provided closed-loop control of exploratory movements, while the distribution of skin deformations, measured by more lateral electrodes and by the hydraulic pressure, were used to estimate material properties of objects. With this control algorithm, the robot plus tactile sensor was able to discriminate the relative compliance of various rubber samples.

The role of tactile sensation in online and offline hierarchical control of multi-finger force synergy.

PubMed

Koh, Kyung; Kwon, Hyun Joon; Yoon, Bum Chul; Cho, Yongseok; Shin, Joon-Ho; Hahn, Jin-Oh; Miller, Ross H; Kim, Yoon Hyuk; Shim, Jae Kun

2015-09-01

The hand, one of the most versatile but mechanically redundant parts of the human body, must overcome imperfect motor commands and inherent noise in both the sensory and motor systems in order to produce desired motor actions. For example, it is nearly impossible to produce a perfectly consistent note during a single violin stroke or to produce the exact same note over multiple strokes, which we denote online and offline control, respectively. To overcome these challenges, the central nervous system synergistically integrates multiple sensory modalities and coordinates multiple motor effectors. Among these sensory modalities, tactile sensation plays an important role in manual motor tasks by providing hand-object contact information. The purpose of this study was to investigate the role of tactile feedback in individual finger actions and multi-finger interactions during constant force production tasks. We developed analytical techniques for the linear decomposition of the overall variance in the motor system in both online and offline control. We removed tactile feedback from the fingers and demonstrated that tactile sensors played a critical role in the online control of synergistic interactions between fingers. In contrast, the same sensors did not contribute to offline control. We also demonstrated that when tactile feedback was removed from the fingers, the combined motor output of individual fingers did not change while individual finger behaviors did. This finding supports the idea of hierarchical control where individual fingers at the lower level work together to stabilize the performance of combined motor output at the higher level.

Nanowire FET Based Neural Element for Robotic Tactile Sensing Skin

PubMed Central

Taube Navaraj, William; García Núñez, Carlos; Shakthivel, Dhayalan; Vinciguerra, Vincenzo; Labeau, Fabrice; Gregory, Duncan H.; Dahiya, Ravinder

2017-01-01

This paper presents novel Neural Nanowire Field Effect Transistors (υ-NWFETs) based hardware-implementable neural network (HNN) approach for tactile data processing in electronic skin (e-skin). The viability of Si nanowires (NWs) as the active material for υ-NWFETs in HNN is explored through modeling and demonstrated by fabricating the first device. Using υ-NWFETs to realize HNNs is an interesting approach as by printing NWs on large area flexible substrates it will be possible to develop a bendable tactile skin with distributed neural elements (for local data processing, as in biological skin) in the backplane. The modeling and simulation of υ-NWFET based devices show that the overlapping areas between individual gates and the floating gate determines the initial synaptic weights of the neural network - thus validating the working of υ-NWFETs as the building block for HNN. The simulation has been further extended to υ-NWFET based circuits and neuronal computation system and this has been validated by interfacing it with a transparent tactile skin prototype (comprising of 6 × 6 ITO based capacitive tactile sensors array) integrated on the palm of a 3D printed robotic hand. In this regard, a tactile data coding system is presented to detect touch gesture and the direction of touch. Following these simulation studies, a four-gated υ-NWFET is fabricated with Pt/Ti metal stack for gates, source and drain, Ni floating gate, and Al2O3 high-k dielectric layer. The current-voltage characteristics of fabricated υ-NWFET devices confirm the dependence of turn-off voltages on the (synaptic) weight of each gate. The presented υ-NWFET approach is promising for a neuro-robotic tactile sensory system with distributed computing as well as numerous futuristic applications such as prosthetics, and electroceuticals. PMID:28979183

Texture- and deformability-based surface recognition by tactile image analysis.

PubMed

Khasnobish, Anwesha; Pal, Monalisa; Tibarewala, D N; Konar, Amit; Pal, Kunal

2016-08-01

Deformability and texture are two unique object characteristics which are essential for appropriate surface recognition by tactile exploration. Tactile sensation is required to be incorporated in artificial arms for rehabilitative and other human-computer interface applications to achieve efficient and human-like manoeuvring. To accomplish the same, surface recognition by tactile data analysis is one of the prerequisites. The aim of this work is to develop effective technique for identification of various surfaces based on deformability and texture by analysing tactile images which are obtained during dynamic exploration of the item by artificial arms whose gripper is fitted with tactile sensors. Tactile data have been acquired, while human beings as well as a robot hand fitted with tactile sensors explored the objects. The tactile images are pre-processed, and relevant features are extracted from the tactile images. These features are provided as input to the variants of support vector machine (SVM), linear discriminant analysis and k-nearest neighbour (kNN) for classification. Based on deformability, six household surfaces are recognized from their corresponding tactile images. Moreover, based on texture five surfaces of daily use are classified. The method adopted in the former two cases has also been applied for deformability- and texture-based recognition of four biomembranes, i.e. membranes prepared from biomaterials which can be used for various applications such as drug delivery and implants. Linear SVM performed best for recognizing surface deformability with an accuracy of 83 % in 82.60 ms, whereas kNN classifier recognizes surfaces of daily use having different textures with an accuracy of 89 % in 54.25 ms and SVM with radial basis function kernel recognizes biomembranes with an accuracy of 78 % in 53.35 ms. The classifiers are observed to generalize well on the unseen test datasets with very high performance to achieve efficient material

Stiffness mapping prostate biopsy samples using a tactile sensor.

PubMed

Peng, Qiyu; Omata, Sadao; Peehl, Donna M; Constantinou, Chris E

2011-01-01

Previous studies have demonstrated that the stiffness of cancerous cells reflects their pathological stage and progression rates, with increased cancerous cell stiffness associated with increased aggressiveness. Therefore, the elasticity of the cancerous cells has the potential to be used as an indicator of the cancer's aggressiveness. However, the sensitivity and resolution of current palpation and imaging techniques are not sufficient to detect small cancerous tissues. In previous studies, we developed a tactile-based device to map with high resolution the stiffness of a tissue section. The purpose of this study is to evaluate this device using different tissues (BPH, Cancer and PZ) collected from human prostates. The preliminary results show that the tactile device is sensitive enough to tell the differences of the stiffness of different tissues. The results also disclosed the factors (humidity, temperature and tissue degradation) which could dramatically affect the results of stiffness mapping. The tactile technology described in this paper has the potential to help disclose the underlying mechanical mechanisms that lead to increased stiffness in prostate tumors.

Softness sensor system for simultaneously measuring the mechanical properties of superficial skin layer and whole skin.

PubMed

Nakatani, Masashi; Fukuda, Toru; Arakawa, Naomi; Kawasoe, Tomoyuki; Omata, Sadao

2013-02-01

Few attempts have been made to distinguish the softness of different skin layers, though specific measurement of the superficial layer would be useful for evaluating the emollient effect of cosmetics and for diagnosis of skin diseases. We developed a sensor probe consisting of a piezoelectric tactile sensor and a load cell. To evaluate it, we firstly measured silicone rubber samples with different softness. Then, it was applied to human forearm skin before and after tape-stripping. A VapoMeter and skin-surface hygrometer were used to confirm removal of the stratum corneum. A Cutometer was used to obtain conventional softness data for comparison. Both the piezoelectric tactile sensor and the load cell could measure the softness of silicone rubber samples, but the piezoelectric tactile sensor was more sensitive than the load cell when the reaction force of the measured sample was under 100 mN in response to a 2-mm indentation. For human skin in vivo, transepidermal water loss and skin conductance were significantly changed after tape-stripping, confirming removal of the stratum corneum. The piezoelectric tactile sensor detected a significant change after tape-stripping, whereas the load cell did not. Thus, the piezoelectric tactile sensor can detect changes of mechanical properties at the skin surface. The load cell data were in agreement with Cutometer measurements, which showed no change in representative skin elasticity parameters after tape-stripping. These results indicate that our sensor can simultaneously measure the mechanical properties of the superficial skin layer and whole skin. © 2012 John Wiley & Sons A/S.

A microfabricated strain gauge array on polymer substrate for tactile neuroprostheses in rats

NASA Astrophysics Data System (ADS)

Beygi, M.; Mutlu, S.; Güçlü, B.

2016-08-01

In this study, we present the design, microfabrication and characterization of a tactile sensor system which can be used for sensory neuroprostheses in rats. The sensor system consists of an array of 2  ×  7 cells, each of which has a series combination of four strain gauges. Each group of four strain gauges is placed around a square membrane with a size of 2.5  ×  2.5 mm2. Unlike most common tactile sensors based on silicon substrates, we used 3D-printed polylactic acid as a substrate, because it is not brittle, and under local extremes, it would prevent the catastrophic failure of all cells. The strain gauges were fabricated by depositing and patterning a 50 nm thick aluminum (Al) film on a polyimide sheet with a thickness of 0.125 mm. Polydimethylsiloxane (PDMS) elastomer was bonded on the top surface of the PI membrane. The PDMS layer was prepared in two different thicknesses, 1.2 and 1.7 mm, to investigate its effect on the static response of the sensor. The sensitivity and the maximum allowable force, corresponding to the maximum deformation of 0.9 mm at the center of each cell, changed based on the thickness of the PDMS layer. Sensor cells operated linearly up to 3 N with an average sensitivity of 200 mΩ N-1 (0.7 Ω mm-1) for 1.2 mm thick PDMS. These values changed to 4 N and 70 mΩ N-1 (0.3 Ω mm-1), respectively, for 1.7 mm thick PDMS. The nonlinearity was less than 3%. The cells had low cross-talk (~5 mΩ N-1 and 0.02 Ω mm-1) relative to the average sensitivity. Additionally, the dynamic response of the sensor was characterized at several frequencies by using a vibrotactile stimulation system previously designed for psychophysics experiments. The sensor was also tested inside the rat conditioning chamber to demonstrate the relevant signals in a tactile neuroprosthesis.

3-Axis Fully-Integrated Capacitive Tactile Sensor with Flip-Bonded CMOS on LTCC Interposer †

PubMed Central

Asano, Sho; Nakayama, Takahiro; Hata, Yoshiyuki; Tanaka, Shuji

2017-01-01

This paper reports a 3-axis fully integrated differential capacitive tactile sensor surface-mountable on a bus line. The sensor integrates a flip-bonded complementary metal-oxide semiconductor (CMOS) with capacitive sensing circuits on a low temperature cofired ceramic (LTCC) interposer with Au through vias by Au-Au thermo-compression bonding. The CMOS circuit and bonding pads on the sensor backside were electrically connected through Au bumps and the LTCC interposer, and the differential capacitive gap was formed by an Au sealing frame. A diaphragm for sensing 3-axis force was formed in the CMOS substrate. The dimensions of the completed sensor are 2.5 mm in width, 2.5 mm in length, and 0.66 mm in thickness. The fabricated sensor output coded 3-axis capacitive sensing data according to applied 3-axis force by three-dimensional (3D)-printed pins. The measured sensitivity was as high as over 34 Count/mN for normal force and 14 to 15 Count/mN for shear force with small noise, which corresponds to less than 1 mN. The hysteresis and the average cross-sensitivity were also found to be less than 2% full scale and 11%, respectively. PMID:29068429

Haptic exploration of fingertip-sized geometric features using a multimodal tactile sensor

NASA Astrophysics Data System (ADS)

Ponce Wong, Ruben D.; Hellman, Randall B.; Santos, Veronica J.

2014-06-01

Haptic perception remains a grand challenge for artificial hands. Dexterous manipulators could be enhanced by "haptic intelligence" that enables identification of objects and their features via touch alone. Haptic perception of local shape would be useful when vision is obstructed or when proprioceptive feedback is inadequate, as observed in this study. In this work, a robot hand outfitted with a deformable, bladder-type, multimodal tactile sensor was used to replay four human-inspired haptic "exploratory procedures" on fingertip-sized geometric features. The geometric features varied by type (bump, pit), curvature (planar, conical, spherical), and footprint dimension (1.25 - 20 mm). Tactile signals generated by active fingertip motions were used to extract key parameters for use as inputs to supervised learning models. A support vector classifier estimated order of curvature while support vector regression models estimated footprint dimension once curvature had been estimated. A distal-proximal stroke (along the long axis of the finger) enabled estimation of order of curvature with an accuracy of 97%. Best-performing, curvature-specific, support vector regression models yielded R2 values of at least 0.95. While a radial-ulnar stroke (along the short axis of the finger) was most helpful for estimating feature type and size for planar features, a rolling motion was most helpful for conical and spherical features. The ability to haptically perceive local shape could be used to advance robot autonomy and provide haptic feedback to human teleoperators of devices ranging from bomb defusal robots to neuroprostheses.

Integration of a sensor based multiple robot environment for space applications: The Johnson Space Center Teleoperator Branch Robotics Laboratory

NASA Technical Reports Server (NTRS)

Hwang, James; Campbell, Perry; Ross, Mike; Price, Charles R.; Barron, Don

1989-01-01

An integrated operating environment was designed to incorporate three general purpose robots, sensors, and end effectors, including Force/Torque Sensors, Tactile Array sensors, Tactile force sensors, and Force-sensing grippers. The design and implementation of: (1) the teleoperation of a general purpose PUMA robot; (2) an integrated sensor hardware/software system; (3) the force-sensing gripper control; (4) the host computer system for dual Robotic Research arms; and (5) the Ethernet integration are described.

Fiber optical sensor system for shape and haptics for flexible instruments in minimally invasive surgery: overview and status quo

NASA Astrophysics Data System (ADS)

Ledermann, Christoph; Pauer, Hendrikje; Woern, Heinz

2014-05-01

In minimally invasive surgery, exible mechatronic instruments promise to improve the overall performance of surgical interventions. However, those instruments require highly developed sensors in order to provide haptic feedback to the surgeon or to enable (semi-)autonomous tasks. Precisely, haptic sensors and a shape sensor are required. In this paper, we present our ber optical sensor system of Fiber Bragg Gratings, which consists of a shape sensor, a kinesthetic sensor and a tactile sensor. The status quo of each of the three sensors is described, as well as the concept to integrate them into one ber optical sensor system.

Tactile feedback for relief of deafferentation pain using virtual reality system: a pilot study.

PubMed

Sano, Yuko; Wake, Naoki; Ichinose, Akimichi; Osumi, Michihiro; Oya, Reishi; Sumitani, Masahiko; Kumagaya, Shin-Ichiro; Kuniyoshi, Yasuo

2016-06-28

Previous studies have tried to relieve deafferentation pain (DP) by using virtual reality rehabilitation systems. However, the effectiveness of multimodal sensory feedback was not validated. The objective of this study is to relieve DP by neurorehabilitation using a virtual reality system with multimodal sensory feedback and to validate the efficacy of tactile feedback on immediate pain reduction. We have developed a virtual reality rehabilitation system with multimodal sensory feedback and applied it to seven patients with DP caused by brachial plexus avulsion or arm amputation. The patients executed a reaching task using the virtual phantom limb manipulated by their real intact limb. The reaching task was conducted under two conditions: one with tactile feedback on the intact hand and one without. The pain intensity was evaluated through a questionnaire. We found that the task with the tactile feedback reduced DP more (41.8 ± 19.8 %) than the task without the tactile feedback (28.2 ± 29.5 %), which was supported by a Wilcoxon signed-rank test result (p < 0.05). Overall, our findings indicate that the tactile feedback improves the immediate pain intensity through rehabilitation using our virtual reality system.

Human detection and discrimination of tactile repeatability, mechanical backlash, and temporal delay in a combined tactile-kinesthetic haptic display system.

PubMed

Doxon, Andrew J; Johnson, David E; Tan, Hong Z; Provancher, William R

2013-01-01

Many of the devices used in haptics research are over-engineered for the task and are designed with capabilities that go far beyond human perception levels. Designing devices that more closely match the limits of human perception will make them smaller, less expensive, and more useful. However, many device-centric perception thresholds have yet to be evaluated. To this end, three experiments were conducted, using one degree-of-freedom contact location feedback device in combination with a kinesthetic display, to provide a more explicit set of specifications for similar tactile-kinesthetic haptic devices. The first of these experiments evaluated the ability of humans to repeatedly localize tactile cues across the fingerpad. Subjects could localize cues to within 1.3 mm and showed bias toward the center of the fingerpad. The second experiment evaluated the minimum perceptible difference of backlash at the tactile element. Subjects were able to discriminate device backlash in excess of 0.46 mm on low-curvature models and 0.93 mm on high-curvature models. The last experiment evaluated the minimum perceptible difference of system delay between user action and device reaction. Subjects were able to discriminate delays in excess of 61 ms. The results from these studies can serve as the maximum (i.e., most demanding) device specifications for most tactile-kinesthetic haptic systems.

P(VDF-TrFE) Polymer-Based Thin Films Deposited on Stainless Steel Substrates Treated Using Water Dissociation for Flexible Tactile Sensor Development

PubMed Central

Tseng, Hong-Jie; Tian, Wei-Cheng; Wu, Wen-Jong

2013-01-01

In this work, deionized (DI) water dissociation was used to treat and change the contact angle of the surface of stainless steel substrates followed by the spin coating of P(VDF-TrFE) material for the fabrication of tactile sensors. The contact angle of the stainless steel surface decreased 14° at −30 V treatment; thus, the adhesion strength between the P(VDF-TrFE) thin film and the stainless steel substrate increased by 90%. Although the adhesion strength was increased at negative voltage treatment, it is observed that the crystallinity value of the P(VDF-TrFE) thin film declined to 37% at −60 V. In addition, the remanent polarization value of the P(VDF-TrFE) thin film declined from 5.6 μC/cm2 to 4.61 μC/cm2 for treatment voltages between −5 V and −60 V. A maximum value of approximately 1000 KV/cm of the coercive field value was obtained with the treatment at −15 V. The d33 value was approximately −10.7 pC/N for the substrate treated at 0 V and reached a minimum of −5 pC/N for treatment at −60 V. By using the P(VDF-TrFE) thin-film as the sensing material for tactile sensors, human pulse measurements were obtained from areas including the carotid, brachial, ankle, radial artery, and apical regions. In addition, the tactile sensor is suitable for monitoring the Cun, Guan, and Chi acupoints located at the radial artery region in Traditional Chinese Medicine (TCM). Waveform measurements of the Cun, Guan, and Chi acupoints are crucial because, in TCM, the various waveforms provided information regarding the health conditions of organs. PMID:24177729

Stereo camera based virtual cane system with identifiable distance tactile feedback for the blind.

PubMed

Kim, Donghun; Kim, Kwangtaek; Lee, Sangyoun

2014-06-13

In this paper, we propose a new haptic-assisted virtual cane system operated by a simple finger pointing gesture. The system is developed by two stages: development of visual information delivery assistant (VIDA) with a stereo camera and adding a tactile feedback interface with dual actuators for guidance and distance feedbacks. In the first stage, user's pointing finger is automatically detected using color and disparity data from stereo images and then a 3D pointing direction of the finger is estimated with its geometric and textural features. Finally, any object within the estimated pointing trajectory in 3D space is detected and the distance is then estimated in real time. For the second stage, identifiable tactile signals are designed through a series of identification experiments, and an identifiable tactile feedback interface is developed and integrated into the VIDA system. Our approach differs in that navigation guidance is provided by a simple finger pointing gesture and tactile distance feedbacks are perfectly identifiable to the blind.

Stereo Camera Based Virtual Cane System with Identifiable Distance Tactile Feedback for the Blind

PubMed Central

Kim, Donghun; Kim, Kwangtaek; Lee, Sangyoun

2014-01-01

In this paper, we propose a new haptic-assisted virtual cane system operated by a simple finger pointing gesture. The system is developed by two stages: development of visual information delivery assistant (VIDA) with a stereo camera and adding a tactile feedback interface with dual actuators for guidance and distance feedbacks. In the first stage, user's pointing finger is automatically detected using color and disparity data from stereo images and then a 3D pointing direction of the finger is estimated with its geometric and textural features. Finally, any object within the estimated pointing trajectory in 3D space is detected and the distance is then estimated in real time. For the second stage, identifiable tactile signals are designed through a series of identification experiments, and an identifiable tactile feedback interface is developed and integrated into the VIDA system. Our approach differs in that navigation guidance is provided by a simple finger pointing gesture and tactile distance feedbacks are perfectly identifiable to the blind. PMID:24932864

A Computational Model of a Descending Mechanosensory Pathway Involved in Active Tactile Sensing

PubMed Central

Ache, Jan M.; Dürr, Volker

2015-01-01

Many animals, including humans, rely on active tactile sensing to explore the environment and negotiate obstacles, especially in the dark. Here, we model a descending neural pathway that mediates short-latency proprioceptive information from a tactile sensor on the head to thoracic neural networks. We studied the nocturnal stick insect Carausius morosus, a model organism for the study of adaptive locomotion, including tactually mediated reaching movements. Like mammals, insects need to move their tactile sensors for probing the environment. Cues about sensor position and motion are therefore crucial for the spatial localization of tactile contacts and the coordination of fast, adaptive motor responses. Our model explains how proprioceptive information about motion and position of the antennae, the main tactile sensors in insects, can be encoded by a single type of mechanosensory afferents. Moreover, it explains how this information is integrated and mediated to thoracic neural networks by a diverse population of descending interneurons (DINs). First, we quantified responses of a DIN population to changes in antennal position, motion and direction of movement. Using principal component (PC) analysis, we find that only two PCs account for a large fraction of the variance in the DIN response properties. We call the two-dimensional space spanned by these PCs ‘coding-space’ because it captures essential features of the entire DIN population. Second, we model the mechanoreceptive input elements of this descending pathway, a population of proprioceptive mechanosensory hairs monitoring deflection of the antennal joints. Finally, we propose a computational framework that can model the response properties of all important DIN types, using the hair field model as its only input. This DIN model is validated by comparison of tuning characteristics, and by mapping the modelled neurons into the two-dimensional coding-space of the real DIN population. This reveals the

Tactile friction of topical formulations.

PubMed

Skedung, L; Buraczewska-Norin, I; Dawood, N; Rutland, M W; Ringstad, L

2016-02-01

The tactile perception is essential for all types of topical formulations (cosmetic, pharmaceutical, medical device) and the possibility to predict the sensorial response by using instrumental methods instead of sensory testing would save time and cost at an early stage product development. Here, we report on an instrumental evaluation method using tactile friction measurements to estimate perceptual attributes of topical formulations. Friction was measured between an index finger and an artificial skin substrate after application of formulations using a force sensor. Both model formulations of liquid crystalline phase structures with significantly different tactile properties, as well as commercial pharmaceutical moisturizing creams being more tactile-similar, were investigated. Friction coefficients were calculated as the ratio of the friction force to the applied load. The structures of the model formulations and phase transitions as a result of water evaporation were identified using optical microscopy. The friction device could distinguish friction coefficients between the phase structures, as well as the commercial creams after spreading and absorption into the substrate. In addition, phase transitions resulting in alterations in the feel of the formulations could be detected. A correlation was established between skin hydration and friction coefficient, where hydrated skin gave rise to higher friction. Also a link between skin smoothening and finger friction was established for the commercial moisturizing creams, although further investigations are needed to analyse this and correlations with other sensorial attributes in more detail. The present investigation shows that tactile friction measurements have potential as an alternative or complement in the evaluation of perception of topical formulations. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Advanced haptic sensor for measuring human skin conditions

NASA Astrophysics Data System (ADS)

Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

2009-12-01

This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

Advanced haptic sensor for measuring human skin conditions

NASA Astrophysics Data System (ADS)

Tsuchimi, Daisuke; Okuyama, Takeshi; Tanaka, Mami

2010-01-01

This paper is concerned with the development of a tactile sensor using PVDF (Polyvinylidene Fluoride) film as a sensory receptor of the sensor to evaluate softness, smoothness, and stickiness of human skin. Tactile sense is the most important sense in the sensation receptor of the human body along with eyesight, and we can examine skin condition quickly using these sense. But, its subjectivity and ambiguity make it difficult to quantify skin conditions. Therefore, development of measurement device which can evaluate skin conditions easily and objectively is demanded by dermatologists, cosmetic industries, and so on. In this paper, an advanced haptic sensor system that can measure multiple information of skin condition in various parts of human body is developed. The applications of the sensor system to evaluate softness, smoothness, and stickiness of skin are investigated through two experiments.

Multimodal Bio-Inspired Tactile Sensing Module for Surface Characterization †

PubMed Central

Alves de Oliveira, Thiago Eustaquio; Cretu, Ana-Maria; Petriu, Emil M.

2017-01-01

Robots are expected to recognize the properties of objects in order to handle them safely and efficiently in a variety of applications, such as health and elder care, manufacturing, or high-risk environments. This paper explores the issue of surface characterization by monitoring the signals acquired by a novel bio-inspired tactile probe in contact with ridged surfaces. The tactile module comprises a nine Degree of Freedom Microelectromechanical Magnetic, Angular Rate, and Gravity system (9-DOF MEMS MARG) and a deep MEMS pressure sensor embedded in a compliant structure that mimics the function and the organization of mechanoreceptors in human skin as well as the hardness of the human skin. When the modules tip slides over a surface, the MARG unit vibrates and the deep pressure sensor captures the overall normal force exerted. The module is evaluated in two experiments. The first experiment compares the frequency content of the data collected in two setups: one when the module is mounted over a linear motion carriage that slides four grating patterns at constant velocities; the second when the module is carried by a robotic finger in contact with the same grating patterns while performing a sliding motion, similar to the exploratory motion employed by humans to detect object roughness. As expected, in the linear setup, the magnitude spectrum of the sensors’ output shows that the module can detect the applied stimuli with frequencies ranging from 3.66 Hz to 11.54 Hz with an overall maximum error of ±0.1 Hz. The second experiment shows how localized features extracted from the data collected by the robotic finger setup over seven synthetic shapes can be used to classify them. The classification method consists on applying multiscale principal components analysis prior to the classification with a multilayer neural network. Achieved accuracies from 85.1% to 98.9% for the various sensor types demonstrate the usefulness of traditional MEMS as tactile sensors embedded

Availability of vision and tactile gating: vision enhances tactile sensitivity.

PubMed

Colino, Francisco L; Lee, Ji-Hang; Binsted, Gordon

2017-01-01

A multitude of events bombard our sensory systems at every moment of our lives. Thus, it is important for the sensory and motor cortices to gate unimportant events. Tactile suppression is a well-known phenomenon defined as a reduced ability to detect tactile events on the skin before and during movement. Previous experiments (Buckingham et al. in Exp Brain Res 201(3):411-419, 2010; Colino et al. in Physiol Rep 2(3):e00267, 2014) found detection rates decrease just prior to and during finger abduction and decrease according to the proximity of the moving effector. However, what effect does vision have on tactile gating? There is ample evidence (see Serino and Haggard in Neurosci Biobehav Rev 34:224-236, 2010) observing increased tactile acuity when participants see their limbs. The present study examined how tactile detection changes in response to visual condition (vision/no vision). Ten human participants used their right hand to reach and grasp a cylinder. Tactors were attached to the index finger and the forearm of both the right and left arm and vibrated at various epochs relative to a "go" tone. Results replicate previous findings from our laboratory (Colino et al. in Physiol Rep 2(3):e00267, 2014). Also, tactile acuity decreased when participants did not have vision. These results indicate that the vision affects the somatosensation via inputs from parietal areas (Konen and Haggard in Cereb Cortex 24(2):501-507, 2014) but does so in a reach-to-grasp context.

A new method for registration of heterogeneous sensors in a dimensional measurement system

NASA Astrophysics Data System (ADS)

Zhao, Yan; Wang, Zhong; Fu, Luhua; Qu, Xinghua; Zhang, Heng; Liu, Changjie

2017-10-01

Registration of multiple sensors is a basic step in multi-sensor dimensional or coordinate measuring systems before any measurement. In most cases, a common standard is used to be measured by all sensors, and this may work well for general registration of multiple homogeneous sensors. However, when inhomogeneous sensors detect a common standard, it is usually very difficult to obtain the same information, because of the different working principles of the sensors. In this paper, a new method called multiple steps registration is proposed to register two sensors: a video camera sensor (VCS) and a tactile probe sensor (TPS). In this method, the two sensors measure two separated standards: a chrome circle on a reticle and a reference sphere with a constant distance between them, fixed on a steel plate. The VCS captures only the circle and the TPS touches only the sphere. Both simulations and real experiments demonstrate that the proposed method is robust and accurate in the registration of multiple inhomogeneous sensors in a dimensional measurement system.

Tactile discrimination, but not tactile stimulation alone, reduces chronic limb pain.

PubMed

Moseley, G Lorimer; Zalucki, Nadia M; Wiech, Katja

2008-07-31

Chronic pain is often associated with reduced tactile acuity. A relationship exists between pain intensity, tactile acuity and cortical reorganisation. When pain resolves, tactile function improves and cortical organisation normalises. Tactile acuity can be improved in healthy controls when tactile stimulation is associated with a behavioural objective. We hypothesised that, in patients with chronic limb pain and decreased tactile acuity, discriminating between tactile stimuli would decrease pain and increase tactile acuity, but tactile stimulation alone would not. Thirteen patients with complex regional pain syndrome (CRPS) of one limb underwent a waiting period and then approximately 2 weeks of tactile stimulation under two conditions: stimulation alone or discrimination between stimuli according to their diameter and location. There was no change in pain (100 mm VAS) or two-point discrimination (TPD) during a no-treatment waiting period, nor during the stimulation phase (p > 0.32 for both). Pain and TPD were lower after the discrimination phase [mean (95% CI) effect size for pain VAS = 27 mm (14-40 mm) and for TPD = 5.7 mm (2.9-8. ), p < 0.015 for both]. These gains were maintained at three-month follow-up. We conclude that tactile stimulation can decrease pain and increase tactile acuity when patients are required to discriminate between the type and location of tactile stimuli.

Enhancing Perception with Tactile Object Recognition in Adaptive Grippers for Human-Robot Interaction.

PubMed

Gandarias, Juan M; Gómez-de-Gabriel, Jesús M; García-Cerezo, Alfonso J

2018-02-26

The use of tactile perception can help first response robotic teams in disaster scenarios, where visibility conditions are often reduced due to the presence of dust, mud, or smoke, distinguishing human limbs from other objects with similar shapes. Here, the integration of the tactile sensor in adaptive grippers is evaluated, measuring the performance of an object recognition task based on deep convolutional neural networks (DCNNs) using a flexible sensor mounted in adaptive grippers. A total of 15 classes with 50 tactile images each were trained, including human body parts and common environment objects, in semi-rigid and flexible adaptive grippers based on the fin ray effect. The classifier was compared against the rigid configuration and a support vector machine classifier (SVM). Finally, a two-level output network has been proposed to provide both object-type recognition and human/non-human classification. Sensors in adaptive grippers have a higher number of non-null tactels (up to 37% more), with a lower mean of pressure values (up to 72% less) than when using a rigid sensor, with a softer grip, which is needed in physical human-robot interaction (pHRI). A semi-rigid implementation with 95.13% object recognition rate was chosen, even though the human/non-human classification had better results (98.78%) with a rigid sensor.

An Examination of the Potential for Blissymbolics to Serve as the Foundation for a Tactile Symbol System

ERIC Educational Resources Information Center

Isaacson, Mickey

2012-01-01

The primary purpose of this study was to determine whether Blissymbolics have the potential for being developed into a tactile symbol communication system. Tactile techniques are used by many individuals with augmentative and alternative communication (AAC) needs. Tactile processing is optimized by the use of minimalistic stimuli, i.e., stimuli…

Tactile agnosia. Underlying impairment and implications for normal tactile object recognition.

PubMed

Reed, C L; Caselli, R J; Farah, M J

1996-06-01

In a series of experimental investigations of a subject with a unilateral impairment of tactile object recognition without impaired tactile sensation, several issues were addressed. First, is tactile agnosia secondary to a general impairment of spatial cognition? On tests of spatial ability, including those directed at the same spatial integration process assumed to be taxed by tactile object recognition, the subject performed well, implying a more specific impairment of high level, modality specific tactile perception. Secondly, within the realm of high level tactile perception, is there a distinction between the ability to derive shape ('what') and spatial ('where') information? Our testing showed an impairment confined to shape perception. Thirdly, what aspects of shape perception are impaired in tactile agnosia? Our results indicate that despite accurate encoding of metric length and normal manual exploration strategies, the ability tactually to perceive objects with the impaired hand, deteriorated as the complexity of shape increased. In addition, asymmetrical performance was not found for other body surfaces (e.g. her feet). Our results suggest that tactile shape perception can be disrupted independent of general spatial ability, tactile spatial ability, manual shape exploration, or even the precise perception of metric length in the tactile modality.

The Tactile Vision Substitution System: Applications in Education and Employment

ERIC Educational Resources Information Center

Scadden, Lawrence A.

1974-01-01

The Tactile Vision Substitution System converts the visual image from a narrow-angle television camera to a tactual image on a 5-inch square, 100-point display of vibrators placed against the abdomen of the blind person. (Author)

The Cognitive and Neural Correlates of Tactile Memory

ERIC Educational Resources Information Center

Gallace, Alberto; Spence, Charles

2009-01-01

Tactile memory systems are involved in the storage and retrieval of information about stimuli that impinge on the body surface and objects that people explore haptically. Here, the authors review the behavioral, neuropsychological, neurophysiological, and neuroimaging research on tactile memory. This body of research reveals that tactile memory…

Inert gas narcosis has no influence on thermo-tactile sensation.

PubMed

Jakovljević, Miroljub; Vidmar, Gaj; Mekjavic, Igor B

2012-05-01

Contribution of skin thermal sensors under inert gas narcosis to the raising hypothermia is not known. Such information is vital for understanding the impact of narcosis on behavioural thermoregulation, diver safety and judgment of thermal (dis)comfort in the hyperbaric environment. So this study aimed at establishing the effects of normoxic concentration of 30% nitrous oxide (N(2)O) on thermo-tactile threshold sensation by studying 16 subjects [eight females and eight males; eight sensitive (S) and eight non-sensitive (NS) to N(2)O]. Their mean (SD) age was 22.1 (1.8) years, weight 72.8 (15.3) kg, height 1.75 (0.10) m and body mass index 23.8 (3.8) kg m(-2). Quantitative thermo-tactile sensory testing was performed on forearm, upper arm and thigh under two experimental conditions: breathing air (air trial) and breathing normoxic mixture of 30% N(2)O (N(2)O trial) in the mixed sequence. Difference in thermo-tactile sensitivity thresholds between two groups of subjects in two experimental conditions was analysed by 3-way mixed-model analysis of covariance. There were no statistically significant differences in thermo-tactile thresholds either between the Air and N(2)O trials, or between S and NS groups, or between females and males, or with respect to body mass index. Some clinically insignificant lowering of thermo-tactile thresholds occurred only for warm thermo-tactile thresholds on upper arm and thigh. The results indicated that normoxic mixture of 30% N(2)O had no influence on thermo-tactile sensation in normothermia.

Scalable, MEMS-enabled, vibrational tactile actuators for high resolution tactile displays

NASA Astrophysics Data System (ADS)

Xie, Xin; Zaitsev, Yuri; Velásquez-García, Luis Fernando; Teller, Seth J.; Livermore, Carol

2014-12-01

The design, fabrication, and characterization of a new type of tactile display for people with blindness or low vision is reported. Each tactile element comprises a piezoelectric extensional actuator that vibrates in plane, with a microfabricated scissor mechanism to convert the in-plane actuations into robust, higher-amplitude, out-of-plane (vertical) vibrations that are sensed with the finger pads. When the tactile elements are formed into a 2D array, information can be conveyed to the user by varying the pattern of vibrations in space and time. Analytical models and finite element analysis were used to design individual tactile elements, which were implemented with PZT actuators and both SU-8 and 3D-printed scissor amplifiers. The measured displacements of these 3 mm × 10 mm, MEMS-enabled tactile elements exceed 10 µm, in agreement with models, with measured forces exceeding 45 mN. The performance of the MEMS-enabled tactile elements is compared with the performance of larger, fully-macroscale tactile elements to demonstrate the scale dependence of the devices. The creation of a 28-element prototype is also reported, and the qualitative user experience with the individual tactile elements and displays is described.

Discrimination of Dynamic Tactile Contact by Temporally Precise Event Sensing in Spiking Neuromorphic Networks

PubMed Central

Lee, Wang Wei; Kukreja, Sunil L.; Thakor, Nitish V.

2017-01-01

This paper presents a neuromorphic tactile encoding methodology that utilizes a temporally precise event-based representation of sensory signals. We introduce a novel concept where touch signals are characterized as patterns of millisecond precise binary events to denote pressure changes. This approach is amenable to a sparse signal representation and enables the extraction of relevant features from thousands of sensing elements with sub-millisecond temporal precision. We also proposed measures adopted from computational neuroscience to study the information content within the spiking representations of artificial tactile signals. Implemented on a state-of-the-art 4096 element tactile sensor array with 5.2 kHz sampling frequency, we demonstrate the classification of transient impact events while utilizing 20 times less communication bandwidth compared to frame based representations. Spiking sensor responses to a large library of contact conditions were also synthesized using finite element simulations, illustrating an 8-fold improvement in information content and a 4-fold reduction in classification latency when millisecond-precise temporal structures are available. Our research represents a significant advance, demonstrating that a neuromorphic spatiotemporal representation of touch is well suited to rapid identification of critical contact events, making it suitable for dynamic tactile sensing in robotic and prosthetic applications. PMID:28197065

Tri-axial tactile sensing element

NASA Astrophysics Data System (ADS)

Castellanos-Ramos, Julián.; Navas-González, Rafael; Vidal-Verdú, F.

2013-05-01

A 13 x 13 square millimetre tri-axial taxel is presented which is suitable for some medical applications, for instance in assistive robotics that involves contact with humans or in prosthetics. Finite Element Analysis is carried out to determine what structure is the best to obtain a uniform distribution of pressure on the sensing areas underneath the structure. This structure has been fabricated in plastic with a 3D printer and a commercial tactile sensor has been used to implement the sensing areas. A three axis linear motorized translation stage with a tri-axial precision force sensor is used to find the parameters of the linear regression model and characterize the proposed taxel. The results are analysed to see to what extent the goal has been reached in this specific implementation.

Magnetic resonance imaging-compatible tactile sensing device based on a piezoelectric array.

PubMed

Hamed, Abbi; Masamune, Ken; Tse, Zion Tsz Ho; Lamperth, Michael; Dohi, Takeyoshi

2012-07-01

Minimally invasive surgery is a widely used medical technique, one of the drawbacks of which is the loss of direct sense of touch during the operation. Palpation is the use of fingertips to explore and make fast assessments of tissue morphology. Although technologies are developed to equip minimally invasive surgery tools with haptic feedback capabilities, the majority focus on tissue stiffness profiling and tool-tissue interaction force measurement. For greatly increased diagnostic capability, a magnetic resonance imaging-compatible tactile sensor design is proposed, which allows minimally invasive surgery to be performed under image guidance, combining the strong capability of magnetic resonance imaging soft tissue and intuitive palpation. The sensing unit is based on a piezoelectric sensor methodology, which conforms to the stringent mechanical and electrical design requirements imposed by the magnetic resonance environment The sensor mechanical design and the device integration to a 0.2 Tesla open magnetic resonance imaging scanner are described, together with the device's magnetic resonance compatibility testing. Its design limitations and potential future improvements are also discussed. A tactile sensing unit based on a piezoelectric sensor principle is proposed, which is designed for magnetic resonance imaging guided interventions.

Image processing for a tactile/vision substitution system using digital CNN.

PubMed

Lin, Chien-Nan; Yu, Sung-Nien; Hu, Jin-Cheng

2006-01-01

In view of the parallel processing and easy implementation properties of CNN, we propose to use digital CNN as the image processor of a tactile/vision substitution system (TVSS). The digital CNN processor is used to execute the wavelet down-sampling filtering and the half-toning operations, aiming to extract important features from the images. A template combination method is used to embed the two image processing functions into a single CNN processor. The digital CNN processor is implemented on an intellectual property (IP) and is implemented on a XILINX VIRTEX II 2000 FPGA board. Experiments are designated to test the capability of the CNN processor in the recognition of characters and human subjects in different environments. The experiments demonstrates impressive results, which proves the proposed digital CNN processor a powerful component in the design of efficient tactile/vision substitution systems for the visually impaired people.

Differential surface models for tactile perception of shape and on-line tracking of features

NASA Technical Reports Server (NTRS)

Hemami, H.

1987-01-01

Tactile perception of shape involves an on-line controller and a shape perceptor. The purpose of the on-line controller is to maintain gliding or rolling contact with the surface, and collect information, or track specific features of the surface such as edges of a certain sharpness. The shape perceptor uses the information to perceive, estimate the parameters of, or recognize the shape. The differential surface model depends on the information collected and on the a priori information known about the robot and its physical parameters. These differential models are certain functionals that are projections of the dynamics of the robot onto the surface gradient or onto the tangent plane. A number of differential properties may be directly measured from present day tactile sensors. Others may have to be indirectly computed from measurements. Others may constitute design objectives for distributed tactile sensors of the future. A parameterization of the surface leads to linear and nonlinear sequential parameter estimation techniques for identification of the surface. Many interesting compromises between measurement and computation are possible.

3D customized and flexible tactile sensor using a piezoelectric nanofiber mat and sandwich-molded elastomer sheets

NASA Astrophysics Data System (ADS)

Bit Lee, Han; Kim, Young Won; Yoon, Jonghun; Lee, Nak Kyu; Park, Suk-Hee

2017-04-01

We developed a skin-conformal flexible sensor in which three-dimensional (3D) free-form elastomeric sheets were harmoniously integrated with a piezoelectric nanofiber mat. The elastomeric sheets were produced by polydimethylsiloxane (PDMS) molding via using a 3D printed mold assembly, which was adaptively designed from 3D scanned skin surface geometry. The mold assembly, fabricated using a multi-material 3D printer, was composed of a pair of upper/lower mold parts and an interconnecting hinge, with material properties are characterized by different flexibilities. As a result of appropriate deformabilites of the upper mold part and hinge, the skin-conformal PDMS structures were successfully sandwich molded and demolded with good repeatability. An electrospun poly(vinylidene fluoride trifluoroethylene) nanofiber mat was prepared as the piezoelectric active layer and integrated with the 3D elastomeric parts. We confirmed that the highly responsive sensing performances of the 3D integrated sensor were identical to those of a flat sensor in terms of sensitivity and the linearity of the input-output relationship. The close 3D conformal skin contact of the flexible sensor enabled discernable perception of various scales of physical stimuli, such as tactile force and even minute skin deformation caused by the tester’s pulse. Collectively from the 3D scanning design to the practical application, our achievements can potentially meet the needs of tailored human interfaces in the field of wearable devices and human-like robots.

Tactile Perception of Roughness and Hardness to Discriminate Materials by Friction-Induced Vibration

PubMed Central

Zhao, Xuezeng

2017-01-01

The human fingertip is an exquisitely powerful bio-tactile sensor in perceiving different materials based on various highly-sensitive mechanoreceptors distributed all over the skin. The tactile perception of surface roughness and material hardness can be estimated by skin vibrations generated during a fingertip stroking of a surface instead of being maintained in a static position. Moreover, reciprocating sliding with increasing velocities and pressures are two common behaviors in humans to discriminate different materials, but the question remains as to what the correlation of the sliding velocity and normal load on the tactile perceptions of surface roughness and hardness is for material discrimination. In order to investigate this correlation, a finger-inspired crossed-I beam structure tactile tester has been designed to mimic the anthropic tactile discrimination behaviors. A novel method of characterizing the fast Fourier transform integral (FFT) slope of the vibration acceleration signal generated from fingertip rubbing on surfaces at increasing sliding velocity and normal load, respectively, are defined as kv and kw, and is proposed to discriminate the surface roughness and hardness of different materials. Over eight types of materials were tested, and they proved the capability and advantages of this high tactile-discriminating method. Our study may find applications in investigating humanoid robot perceptual abilities. PMID:29182538

Computational optical palpation: a finite-element approach to micro-scale tactile imaging using a compliant sensor

PubMed Central

Sampson, David D.; Kennedy, Brendan F.

2017-01-01

High-resolution tactile imaging, superior to the sense of touch, has potential for future biomedical applications such as robotic surgery. In this paper, we propose a tactile imaging method, termed computational optical palpation, based on measuring the change in thickness of a thin, compliant layer with optical coherence tomography and calculating tactile stress using finite-element analysis. We demonstrate our method on test targets and on freshly excised human breast fibroadenoma, demonstrating a resolution of up to 15–25 µm and a field of view of up to 7 mm. Our method is open source and readily adaptable to other imaging modalities, such as ultrasonography and confocal microscopy. PMID:28250098

A New Model Based on Adaptation of the External Loop to Compensate the Hysteresis of Tactile Sensors

PubMed Central

Sánchez-Durán, José A.; Vidal-Verdú, Fernando; Oballe-Peinado, Óscar; Castellanos-Ramos, Julián; Hidalgo-López, José A.

2015-01-01

This paper presents a novel method to compensate for hysteresis nonlinearities observed in the response of a tactile sensor. The External Loop Adaptation Method (ELAM) performs a piecewise linear mapping of the experimentally measured external curves of the hysteresis loop to obtain all possible internal cycles. The optimal division of the input interval where the curve is approximated is provided by the error minimization algorithm. This process is carried out off line and provides parameters to compute the split point in real time. A different linear transformation is then performed at the left and right of this point and a more precise fitting is achieved. The models obtained with the ELAM method are compared with those obtained from three other approaches. The results show that the ELAM method achieves a more accurate fitting. Moreover, the involved mathematical operations are simpler and therefore easier to implement in devices such as Field Programmable Gate Array (FPGAs) for real time applications. Furthermore, the method needs to identify fewer parameters and requires no previous selection process of operators or functions. Finally, the method can be applied to other sensors or actuators with complex hysteresis loop shapes. PMID:26501279

Tactile perception of skin and skin cream by friction induced vibrations.

PubMed

Ding, Shuyang; Bhushan, Bharat

2016-11-01

Skin cream smooths, softens, and moistens skin by altering surface roughness and tribological properties of skin. Sliding generates vibrations that activate mechanoreceptors located in skin. The brain interprets tactile information to identify skin feel. Understanding the tactile sensing mechanisms of skin with and without cream treatment is important to numerous applications including cosmetics, textiles, and robotics sensors. In this study, frequency spectra of friction force and friction induced vibration signals were carried out to investigate tactile perception by an artificial finger sliding on skin. The influence of normal load, velocity, and cream treatment time were studied. Coherence between friction force and vibration signals were found. The amplitude of vibration decreased after cream treatment, leading to smoother perception. Increasing normal load or velocity between contacting surfaces generated a smoother perception with cream treatment, but rougher perception without treatment. As cream treatment time increases, skin becomes smoother. The related mechanisms are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

Tactile Signing with One-Handed Perception

ERIC Educational Resources Information Center

Mesch, Johanna

2013-01-01

Tactile signing among persons with deaf-blindness is not homogenous; rather, like other forms of language, it exhibits variation, especially in turn taking. Early analyses of tactile Swedish Sign Language, tactile Norwegian Sign Language, and tactile French Sign Language focused on tactile communication with four hands, in which partially blind or…

Design of Tactile Sensor Using Dynamic Wafer Technology Based on VLSI Technique

DTIC Science & Technology

2001-10-25

Charles Noback, Rober Carola," Human Anatomy and Physiology" third edition, 1995. [5] M.H. Raibert and John E. Tanner, "Design and Implementation of VLSI Tactile Sensing Computer" Robotics Research vol 1, 1983.

Why Early Tactile Speech Aids May Have Failed: No Perceptual Integration of Tactile and Auditory Signals.

PubMed

Rizza, Aurora; Terekhov, Alexander V; Montone, Guglielmo; Olivetti-Belardinelli, Marta; O'Regan, J Kevin

2018-01-01

Tactile speech aids, though extensively studied in the 1980's and 1990's, never became a commercial success. A hypothesis to explain this failure might be that it is difficult to obtain true perceptual integration of a tactile signal with information from auditory speech: exploitation of tactile cues from a tactile aid might require cognitive effort and so prevent speech understanding at the high rates typical of everyday speech. To test this hypothesis, we attempted to create true perceptual integration of tactile with auditory information in what might be considered the simplest situation encountered by a hearing-impaired listener. We created an auditory continuum between the syllables /BA/ and /VA/, and trained participants to associate /BA/ to one tactile stimulus and /VA/ to another tactile stimulus. After training, we tested if auditory discrimination along the continuum between the two syllables could be biased by incongruent tactile stimulation. We found that such a bias occurred only when the tactile stimulus was above, but not when it was below its previously measured tactile discrimination threshold. Such a pattern is compatible with the idea that the effect is due to a cognitive or decisional strategy, rather than to truly perceptual integration. We therefore ran a further study (Experiment 2), where we created a tactile version of the McGurk effect. We extensively trained two Subjects over 6 days to associate four recorded auditory syllables with four corresponding apparent motion tactile patterns. In a subsequent test, we presented stimulation that was either congruent or incongruent with the learnt association, and asked Subjects to report the syllable they perceived. We found no analog to the McGurk effect, suggesting that the tactile stimulation was not being perceptually integrated with the auditory syllable. These findings strengthen our hypothesis according to which tactile aids failed because integration of tactile cues with auditory speech

Why Early Tactile Speech Aids May Have Failed: No Perceptual Integration of Tactile and Auditory Signals

PubMed Central

Rizza, Aurora; Terekhov, Alexander V.; Montone, Guglielmo; Olivetti-Belardinelli, Marta; O’Regan, J. Kevin

2018-01-01

Tactile speech aids, though extensively studied in the 1980’s and 1990’s, never became a commercial success. A hypothesis to explain this failure might be that it is difficult to obtain true perceptual integration of a tactile signal with information from auditory speech: exploitation of tactile cues from a tactile aid might require cognitive effort and so prevent speech understanding at the high rates typical of everyday speech. To test this hypothesis, we attempted to create true perceptual integration of tactile with auditory information in what might be considered the simplest situation encountered by a hearing-impaired listener. We created an auditory continuum between the syllables /BA/ and /VA/, and trained participants to associate /BA/ to one tactile stimulus and /VA/ to another tactile stimulus. After training, we tested if auditory discrimination along the continuum between the two syllables could be biased by incongruent tactile stimulation. We found that such a bias occurred only when the tactile stimulus was above, but not when it was below its previously measured tactile discrimination threshold. Such a pattern is compatible with the idea that the effect is due to a cognitive or decisional strategy, rather than to truly perceptual integration. We therefore ran a further study (Experiment 2), where we created a tactile version of the McGurk effect. We extensively trained two Subjects over 6 days to associate four recorded auditory syllables with four corresponding apparent motion tactile patterns. In a subsequent test, we presented stimulation that was either congruent or incongruent with the learnt association, and asked Subjects to report the syllable they perceived. We found no analog to the McGurk effect, suggesting that the tactile stimulation was not being perceptually integrated with the auditory syllable. These findings strengthen our hypothesis according to which tactile aids failed because integration of tactile cues with auditory speech

A chameleon-inspired stretchable electronic skin with interactive colour changing controlled by tactile sensing

PubMed Central

Chou, Ho-Hsiu; Nguyen, Amanda; Chortos, Alex; To, John W.F.; Lu, Chien; Mei, Jianguo; Kurosawa, Tadanori; Bae, Won-Gyu; Tok, Jeffrey B.-H.; Bao, Zhenan

2015-01-01

Some animals, such as the chameleon and cephalopod, have the remarkable capability to change their skin colour. This unique characteristic has long inspired scientists to develop materials and devices to mimic such a function. However, it requires the complex integration of stretchability, colour-changing and tactile sensing. Here we show an all-solution processed chameleon-inspired stretchable electronic skin (e-skin), in which the e-skin colour can easily be controlled through varying the applied pressure along with the applied pressure duration. As such, the e-skin's colour change can also be in turn utilized to distinguish the pressure applied. The integration of the stretchable, highly tunable resistive pressure sensor and the fully stretchable organic electrochromic device enables the demonstration of a stretchable electrochromically active e-skin with tactile-sensing control. This system will have wide range applications such as interactive wearable devices, artificial prosthetics and smart robots. PMID:26300307

A chameleon-inspired stretchable electronic skin with interactive colour changing controlled by tactile sensing.

PubMed

Chou, Ho-Hsiu; Nguyen, Amanda; Chortos, Alex; To, John W F; Lu, Chien; Mei, Jianguo; Kurosawa, Tadanori; Bae, Won-Gyu; Tok, Jeffrey B-H; Bao, Zhenan

2015-08-24

Some animals, such as the chameleon and cephalopod, have the remarkable capability to change their skin colour. This unique characteristic has long inspired scientists to develop materials and devices to mimic such a function. However, it requires the complex integration of stretchability, colour-changing and tactile sensing. Here we show an all-solution processed chameleon-inspired stretchable electronic skin (e-skin), in which the e-skin colour can easily be controlled through varying the applied pressure along with the applied pressure duration. As such, the e-skin's colour change can also be in turn utilized to distinguish the pressure applied. The integration of the stretchable, highly tunable resistive pressure sensor and the fully stretchable organic electrochromic device enables the demonstration of a stretchable electrochromically active e-skin with tactile-sensing control. This system will have wide range applications such as interactive wearable devices, artificial prosthetics and smart robots.

Performance of a novel micro force vector sensor and outlook into its biomedical applications

NASA Astrophysics Data System (ADS)

Meiss, Thorsten; Rossner, Tim; Minamisava Faria, Carlos; Völlmeke, Stefan; Opitz, Thomas; Werthschützky, Roland

2011-05-01

For the HapCath system, which provides haptic feedback of the forces acting on a guide wire's tip during vascular catheterization, very small piezoresistive force sensors of 200•200•640μm3 have been developed. This paper focuses on the characterization of the measurement performance and on possible new applications. Besides the determination of the dynamic measurement performance, special focus is put onto the results of the 3- component force vector calibration. This article addresses special advantageous characteristics of the sensor, but also the limits of applicability will be addressed. As for the special characteristics of the sensor, the second part of the article demonstrates new applications which can be opened up with the novel force sensor, like automatic navigation of medical or biological instruments without impacting surrounding tissue, surface roughness evaluation in biomedical systems, needle insertion with tactile or higher level feedback, or even building tactile hairs for artificial organisms.

Hair-based sensors for micro-autonomous systems

NASA Astrophysics Data System (ADS)

Sadeghi, Mahdi M.; Peterson, Rebecca L.; Najafi, Khalil

2012-06-01

We seek to harness microelectromechanical systems (MEMS) technologies to build biomimetic devices for low-power, high-performance, robust sensors and actuators on micro-autonomous robot platforms. Hair is used abundantly in nature for a variety of functions including balance and inertial sensing, flow sensing and aerodynamic (air foil) control, tactile and touch sensing, insulation and temperature control, particle filtering, and gas/chemical sensing. Biological hairs, which are typically characterized by large surface/volume ratios and mechanical amplification of movement, can be distributed in large numbers over large areas providing unprecedented sensitivity, redundancy, and stability (robustness). Local neural transduction allows for space- and power-efficient signal processing. Moreover by varying the hair structure and transduction mechanism, the basic hair form can be used for a wide diversity of functions. In this paper, by exploiting a novel wafer-level, bubble-free liquid encapsulation technology, we make arrays of micro-hydraulic cells capable of electrostatic actuation and hydraulic amplification, which enables high force/high deflection actuation and extremely sensitive detection (sensing) at low power. By attachment of cilia (hair) to the micro-hydraulic cell, air flow sensors with excellent sensitivity (< few cm/s) and dynamic range (> 10 m/s) have been built. A second-generation design has significantly reduced the sensor response time while maintaining sensitivity of about 2 cm/s and dynamic range of more than 15 m/s. These sensors can be used for dynamic flight control of flying robots or for situational awareness in surveillance applications. The core biomimetic technologies developed are applicable to a broad range of sensors and actuators.

Psychophysical evaluation of a variable friction tactile interface

NASA Astrophysics Data System (ADS)

Samur, Evren; Colgate, J. Edward; Peshkin, Michael A.

2009-02-01

This study explores the haptic rendering capabilities of a variable friction tactile interface through psychophysical experiments. In order to obtain a deeper understanding of the sensory resolution associated with the Tactile Pattern Display (TPaD), friction discrimination experiments are conducted. During the experiments, subjects are asked to explore the glass surface of the TPaD using their bare index fingers, to feel the friction on the surface, and to compare the slipperiness of two stimuli, displayed in sequential order. The fingertip position data is collected by an infrared frame and normal and translational forces applied by the finger are measured by force sensors attached to the TPaD. The recorded data is used to calculate the coefficient of friction between the fingertip and the TPaD. The experiments determine the just noticeable difference (JND) of friction coefficient for humans interacting with the TPaD.

Studies to design and develop improved remote manipulator systems

NASA Technical Reports Server (NTRS)

Hill, J. W.; Sword, A. J.

1973-01-01

Remote manipulator control considered is based on several levels of automatic supervision which derives manipulator commands from an analysis of sensor states and task requirements. Principle sensors are manipulator joint position, tactile, and currents. The tactile sensor states can be displayed visually in perspective or replicated in the operator's control handle of perceived by the automatic supervisor. Studies are reported on control organization, operator performance and system performance measures. Unusual hardware and software details are described.

Path integration in tactile perception of shapes.

PubMed

Moscatelli, Alessandro; Naceri, Abdeldjallil; Ernst, Marc O

2014-11-01

Whenever we move the hand across a surface, tactile signals provide information about the relative velocity between the skin and the surface. If the system were able to integrate the tactile velocity information over time, cutaneous touch may provide an estimate of the relative displacement between the hand and the surface. Here, we asked whether humans are able to form a reliable representation of the motion path from tactile cues only, integrating motion information over time. In order to address this issue, we conducted three experiments using tactile motion and asked participants (1) to estimate the length of a simulated triangle, (2) to reproduce the shape of a simulated triangular path, and (3) to estimate the angle between two-line segments. Participants were able to accurately indicate the length of the path, whereas the perceived direction was affected by a direction bias (inward bias). The response pattern was thus qualitatively similar to the ones reported in classical path integration studies involving locomotion. However, we explain the directional biases as the result of a tactile motion aftereffect. Copyright © 2014 Elsevier B.V. All rights reserved.

Fast and precise large area metrology of micropattern detectors using laser distance sensors

NASA Astrophysics Data System (ADS)

Müller, R.; Biebel, O.; Hertenberger, R.; Lösel, P.; Schaile, O.

2016-07-01

Novel developments in micropattern detector technology require fast and precise methods to measure large area topologies in the order of a few square meters. Standard tactile coordinate measurement systems have resolutions better 10 μm, but suffer from relatively long measuring time of several hours for one cycle. Sensitive structures may be damaged when touched by the tactile sensor. We present a method using laser distance sensors. Such a device is able to scan surfaces fast without touching them. The presented device has the capability to measure semitransparent surfaces. The vertical translator to mount the sensor is able to move in sub-mm steps. Using this we are able to measure the position and height of copper on FR4 with an accuracy better than 10 μm. We report on the performance of the sensor scanning non-transparent as well as semi-transparent surfaces. This includes studies to minimize the measurement time without a loss in resolution. Our method to calibrate the measurement system will also be shown. This calibration is needed to reach a resolution better than 10 μm.

Tactile Sensitivity in Asperger Syndrome

ERIC Educational Resources Information Center

Blakemore, Sarah-Jayne; Tavassoli, Teresa; Calo, Susana; Thomas, Richard M.; Catmur, Caroline; Frith, Uta; Haggard, Patrick

2006-01-01

People with autism and Asperger syndrome are anecdotally said to be hypersensitive to touch. In two experiments, we measured tactile thresholds and suprathreshold tactile sensitivity in a group of adults with Asperger syndrome. In the first experiment, tactile perceptual thresholds were measured. Two frequencies of vibrotactile stimulation were…

Synthetic and Bio-Artificial Tactile Sensing: A Review

PubMed Central

Lucarotti, Chiara; Oddo, Calogero Maria; Vitiello, Nicola; Carrozza, Maria Chiara

2013-01-01

This paper reviews the state of the art of artificial tactile sensing, with a particular focus on bio-hybrid and fully-biological approaches. To this aim, the study of physiology of the human sense of touch and of the coding mechanisms of tactile information is a significant starting point, which is briefly explored in this review. Then, the progress towards the development of an artificial sense of touch are investigated. Artificial tactile sensing is analysed with respect to the possible approaches to fabricate the outer interface layer: synthetic skin versus bio-artificial skin. With particular respect to the synthetic skin approach, a brief overview is provided on various technologies and transduction principles that can be integrated beneath the skin layer. Then, the main focus moves to approaches characterized by the use of bio-artificial skin as an outer layer of the artificial sensory system. Within this design solution for the skin, bio-hybrid and fully-biological tactile sensing systems are thoroughly presented: while significant results have been reported for the development of tissue engineered skins, the development of mechanotransduction units and their integration is a recent trend that is still lagging behind, therefore requiring research efforts and investments. In the last part of the paper, application domains and perspectives of the reviewed tactile sensing technologies are discussed. PMID:23348032

Mechanisms underlying a thalamocortical transformation during active tactile sensation

PubMed Central

Gutnisky, Diego Adrian; Yu, Jianing; Hires, Samuel Andrew; To, Minh-Son; Svoboda, Karel

2017-01-01

During active somatosensation, neural signals expected from movement of the sensors are suppressed in the cortex, whereas information related to touch is enhanced. This tactile suppression underlies low-noise encoding of relevant tactile features and the brain’s ability to make fine tactile discriminations. Layer (L) 4 excitatory neurons in the barrel cortex, the major target of the somatosensory thalamus (VPM), respond to touch, but have low spike rates and low sensitivity to the movement of whiskers. Most neurons in VPM respond to touch and also show an increase in spike rate with whisker movement. Therefore, signals related to self-movement are suppressed in L4. Fast-spiking (FS) interneurons in L4 show similar dynamics to VPM neurons. Stimulation of halorhodopsin in FS interneurons causes a reduction in FS neuron activity and an increase in L4 excitatory neuron activity. This decrease of activity of L4 FS neurons contradicts the "paradoxical effect" predicted in networks stabilized by inhibition and in strongly-coupled networks. To explain these observations, we constructed a model of the L4 circuit, with connectivity constrained by in vitro measurements. The model explores the various synaptic conductance strengths for which L4 FS neurons actively suppress baseline and movement-related activity in layer 4 excitatory neurons. Feedforward inhibition, in concert with recurrent intracortical circuitry, produces tactile suppression. Synaptic delays in feedforward inhibition allow transmission of temporally brief volleys of activity associated with touch. Our model provides a mechanistic explanation of a behavior-related computation implemented by the thalamocortical circuit. PMID:28591219

Dissociated active and passive tactile shape recognition: a case study of pure tactile apraxia.

PubMed

Valenza, N; Ptak, R; Zimine, I; Badan, M; Lazeyras, F; Schnider, A

2001-11-01

Disorders of tactile object recognition (TOR) may result from primary motor or sensory deficits or higher cognitive impairment of tactile shape representations or semantic memory. Studies with healthy participants suggest the existence of exploratory motor procedures directly linked to the extraction of specific properties of objects. A pure deficit of these procedures without concomitant gnostic disorders has never been described in a brain-damaged patient. Here, we present a patient with a right hemispheric infarction who, in spite of intact sensorimotor functions, had impaired TOR with the left hand. Recognition of 2D shapes and objects was severely deficient under the condition of spontaneous exploration. Tactile exploration of shapes was disorganized and exploratory procedures, such as the contour-following strategy, which is necessary to identify the precise shape of an object, were severely disturbed. However, recognition of 2D shapes under manually or verbally guided exploration and the recognition of shapes traced on the skin were intact, indicating a dissociation in shape recognition between active and passive touch. Functional MRI during sensory stimulation of the left hand showed preserved activation of the spared primary sensory cortex in the right hemisphere. We interpret the deficit of our patient as a pure tactile apraxia without tactile agnosia, i.e. a specific inability to use tactile feedback to generate the exploratory procedures necessary for tactile shape recognition.

Flexible Skins Containing Integrated Sensors and Circuitry

NASA Technical Reports Server (NTRS)

Liu, Chang

2007-01-01

Artificial sensor skins modeled partly in imitation of biological sensor skins are undergoing development. These sensor skins comprise flexible polymer substrates that contain and/or support dense one- and two-dimensional arrays of microscopic sensors and associated microelectronic circuits. They afford multiple tactile sensing modalities for measuring physical phenomena that can include contact forces; hardnesses, temperatures, and thermal conductivities of objects with which they are in contact; and pressures, shear stresses, and flow velocities in fluids. The sensor skins are mechanically robust, and, because of their flexibility, they can be readily attached to curved and possibly moving and flexing surfaces of robots, wind-tunnel models, and other objects that one might seek to equip for tactile sensing. Because of the diversity of actual and potential sensor-skin design criteria and designs and the complexity of the fabrication processes needed to realize the designs, it is not possible to describe the sensor-skin concept in detail within this article.

Merkel cells transduce and encode tactile stimuli to drive Aβ-afferent impulses

PubMed Central

Ikeda, Ryo; Cha, Myeounghoon; Ling, Jennifer; Jia, Zhanfeng; Coyle, Dennis; Gu, Jianguo G.

2014-01-01

SUMMARY Sensory systems for detecting tactile stimuli have evolved from touch-sensing nerves in invertebrates to complicated tactile end-organs in mammals. Merkel discs are tactile end-organs consisting of Merkel cells and Aβ-afferent nerve endings, and are localized in fingertips, whisker hair follicles and other touch-sensitive spots. Merkel discs transduce touch into slowly adapting impulses to enable tactile discrimination, but their transduction and encoding mechanisms remain unknown. Using rat whisker hair follicles, we show that Merkel cells rather than Aβ-afferent nerve endings are primary sites of tactile transduction, and identify the Piezo2 ion channel as the Merkel cell mechanical transducer. Piezo2 transduces tactile stimuli into Ca2+-action potentials in Merkel cells, which drive Aβ-afferent nerve endings to fire slowly adapting impulses. We further demonstrate that Piezo2 and Ca2+-action potentials in Merkel cells are required for behavioral tactile responses. Our findings provide insights into how tactile end-organs function and have clinical implications for tactile dysfunctions. PMID:24746027

Tactile functions after cerebral hemispherectomy.

PubMed

Backlund, H; Morin, C; Ptito, A; Bushnell, M C; Olausson, H

2005-01-01

Patients that were hemispherectomized due to brain lesions early in life sometimes have remarkably well-preserved tactile functions on their paretic body half. This has been attributed to developmental neuroplasticity. However, the tactile examinations generally have been fairly crude, and subtle deficits may not have been revealed. We investigated monofilament detection and three types of tactile directional sensibility in four hemispherectomized patients and six healthy controls. Patients were examined bilaterally on the face, forearm and lower leg. Normal subjects were examined unilaterally. Following each test of directional sensibility, subjects were asked to rate the intensity of the stimulation. On the nonparetic side, results were almost always in the normal range. On the paretic side, the patients' capacity for monofilament detection was less impaired than their directional sensibility. Despite the disturbed directional sensibility on their paretic side the patients rated tactile sensations evoked by the stimuli, on both their paretic and nonparetic body halves, as more intense than normals. Thus, mechanisms of plasticity seem adequate for tactile detection and intensity coding but not for more complex tactile functions such as directional sensibility. The reason for the high vulnerability of tactile directional sensibility may be that it depends on spatially and temporally precise afferent information processed in a distributed cortical network.

Tactile modulation of hippocampal place fields.

PubMed

Gener, Thomas; Perez-Mendez, Lorena; Sanchez-Vives, Maria V

2013-12-01

Neural correlates of spatial representation can be found in the activity of the hippocampal place cells. These neurons are characterized by firing whenever the animal is located in a particular area of the space, the place field. Place fields are modulated by sensory cues, such as visual, auditory, or olfactory cues, being the influence of visual inputs the most thoroughly studied. Tactile information gathered by the whiskers has a prominent representation in the rat cerebral cortex. However, the influence of whisker-detected tactile cues on place fields remains an open question. Here we studied place fields in an enriched tactile environment where the remaining sensory cues were occluded. First, place cells were recorded before and after blockade of tactile transmission by means of lidocaine applied on the whisker pad. Following tactile deprivation, the majority of place cells decreased their firing rate and their place fields expanded. We next rotated the tactile cues and 90% of place fields rotated with them. Our results demonstrate that tactile information is integrated into place cells at least in a tactile-enriched arena and when other sensory cues are not available. Copyright © 2013 Wiley Periodicals, Inc.

A tactile sensing element based on a hetero-core optical fiber for force measurement and texture detection

NASA Astrophysics Data System (ADS)

Yamazaki, Hiroshi; Koyama, Yuya; Watanabe, Kazuhiro

2014-05-01

Tactile sensing technology can measure a given property of an object through physical contact between a sensing element and the object. Various tactile sensing techniques have been developed for several applications such as intelligent robots, tactile interface, medical support and nursing care support. A desirable tactile sensing element for supporting human daily life can be embedded in the soft material with high sensitivity and accuracy in order to prevent from damaging to human or object physically. This report describes a new tactile sensing element. Hetero-core optical fibers have high sensitivity of macro-bending at local sensor portion and temperature independency, including advantages of optical fiber itself; thin size, light weight, flexible transmission line, and immunity to electro-magnetic interference. The proposed tactile sensing element could detect textures of touched objects through the optical loss caused by the force applied to the sensing element. The characteristics of the sensing element have been evaluated, in which the sensing element has the monotonic and non-linear sensitivity against the normal force ranged from 0 to 5 N with lower accuracy than 0.25 dB. Additionally, texture detection have been successfully demonstrated in which small surface figures of 0.1 mm in height were detected with spatial resolution of 0.4 mm.

Coalition Warfare Program Tactile Situation Awareness System for Aviation Applications: Simulator Flight Test

DTIC Science & Technology

2015-12-01

David Myers1 Timothy Gowen2 Angus Rupert3 Ben Lawson3 Justin Dailey3,4 1Chesapeake Technology International 2Naval Aviation Center for... Angus Rupert of the USAARL. The algorithm is described in “Configuration Parameters for the Tactile Situation Awareness System (TSAS)” dated July 2010

Nanomaterial-Enabled Wearable Sensors for Healthcare.

PubMed

Yao, Shanshan; Swetha, Puchakayala; Zhu, Yong

2018-01-01

Highly sensitive wearable sensors that can be conformably attached to human skin or integrated with textiles to monitor the physiological parameters of human body or the surrounding environment have garnered tremendous interest. Owing to the large surface area and outstanding material properties, nanomaterials are promising building blocks for wearable sensors. Recent advances in the nanomaterial-enabled wearable sensors including temperature, electrophysiological, strain, tactile, electrochemical, and environmental sensors are presented in this review. Integration of multiple sensors for multimodal sensing and integration with other components into wearable systems are summarized. Representative applications of nanomaterial-enabled wearable sensors for healthcare, including continuous health monitoring, daily and sports activity tracking, and multifunctional electronic skin are highlighted. Finally, challenges, opportunities, and future perspectives in the field of nanomaterial-enabled wearable sensors are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nitride-Based Materials for Flexible MEMS Tactile and Flow Sensors in Robotics

PubMed Central

Abels, Claudio; Mastronardi, Vincenzo Mariano; Guido, Francesco; Dattoma, Tommaso; Qualtieri, Antonio; Megill, William M.; De Vittorio, Massimo; Rizzi, Francesco

2017-01-01

The response to different force load ranges and actuation at low energies is of considerable interest for applications of compliant and flexible devices undergoing large deformations. We present a review of technological platforms based on nitride materials (aluminum nitride and silicon nitride) for the microfabrication of a class of flexible micro-electro-mechanical systems. The approach exploits the material stress differences among the constituent layers of nitride-based (AlN/Mo, SixNy/Si and AlN/polyimide) mechanical elements in order to create microstructures, such as upwardly-bent cantilever beams and bowed circular membranes. Piezoresistive properties of nichrome strain gauges and direct piezoelectric properties of aluminum nitride can be exploited for mechanical strain/stress detection. Applications in flow and tactile sensing for robotics are described. PMID:28489040

Incrementally learning objects by touch: online discriminative and generative models for tactile-based recognition.

PubMed

Soh, Harold; Demiris, Yiannis

2014-01-01

Human beings not only possess the remarkable ability to distinguish objects through tactile feedback but are further able to improve upon recognition competence through experience. In this work, we explore tactile-based object recognition with learners capable of incremental learning. Using the sparse online infinite Echo-State Gaussian process (OIESGP), we propose and compare two novel discriminative and generative tactile learners that produce probability distributions over objects during object grasping/palpation. To enable iterative improvement, our online methods incorporate training samples as they become available. We also describe incremental unsupervised learning mechanisms, based on novelty scores and extreme value theory, when teacher labels are not available. We present experimental results for both supervised and unsupervised learning tasks using the iCub humanoid, with tactile sensors on its five-fingered anthropomorphic hand, and 10 different object classes. Our classifiers perform comparably to state-of-the-art methods (C4.5 and SVM classifiers) and findings indicate that tactile signals are highly relevant for making accurate object classifications. We also show that accurate "early" classifications are possible using only 20-30 percent of the grasp sequence. For unsupervised learning, our methods generate high quality clusterings relative to the widely-used sequential k-means and self-organising map (SOM), and we present analyses into the differences between the approaches.

Tactile Sensitivity of Children: Effects of Frequency, Masking, and the Non-Pacinian I Psychophysical Channel

ERIC Educational Resources Information Center

Guclu, Burak; Oztek, Cigdem

2007-01-01

Tactile perception depends on the contributions of four psychophysical tactile channels mediated by four corresponding receptor systems. The sensitivity of the tactile channels is determined by detection thresholds that vary as a function of the stimulus frequency. It has been widely reported that tactile thresholds increase (i.e., sensitivity…

Flexible Tactile Sensing Based on Piezoresistive Composites: A Review

PubMed Central

Stassi, Stefano; Cauda, Valentina; Canavese, Giancarlo; Pirri, Candido Fabrizio

2014-01-01

The large expansion of the robotic field in the last decades has created a growing interest in the research and development of tactile sensing solutions for robot hand and body integration. Piezoresistive composites are one of the most widely employed materials for this purpose, combining simple and low cost preparation with high flexibility and conformability to surfaces, low power consumption, and the use of simple read-out electronics. This work provides a review on the different type of composite materials, classified according to the conduction mechanism and analyzing the physics behind it. In particular piezoresistors, strain gauges, percolative and quantum tunnelling devices are reviewed here, with a perspective overview on the most used filler types and polymeric matrices. A description of the state-of-the-art of the tactile sensor solutions from the point of view of the architecture, the design and the performance is also reviewed, with a perspective outlook on the main promising applications. PMID:24638126

Tactile display device using an electrorheological fluid

NASA Technical Reports Server (NTRS)

Garner, H. Douglas (Inventor)

1994-01-01

A tactile display device utilizes an electrorheological fluid to activate a plurality of tactile dots. A voltage is selectively produced uniformly across an electrorheological fluid flowing between a common ground electrode and a plurality of conductive dot electrodes, thereby producing an increase in the fluid's viscosity to the extent that fluid flow between the two electrodes is restricted. The flow restriction produces a build-up of electrorheological fluid in a corresponding dot actuator chamber. The resulting pressure increase in the chamber displaces an elastic diaphragm fixed to a display surface to form a lump which can be perceived by the reader as one dot in a Braille character cell. A flow regulation system provides a continually pressurized flow system and provides for free flow of the electrorheological fluid through the plurality of dot actuator chambers when they are not activated. The device is adaptable to printed circuit techniques and can simultaneously display tactile dots representative of a full page of Braille characters stored on a medium such as a tape cassette or to display tactile dots representative of non-Braille data appearing on a computer monitor or contained on another data storage medium. In an alternate embodiment, the elastic diaphragm drives a plurality of spring-loaded pins provided with positive stops to maintain consistent displacements of the pins in both their actuated and nonactuated positions.

A Single Session of Mirror-based Tactile and Motor Training Improves Tactile Dysfunction in Children with Unilateral Cerebral Palsy: A Replicated Randomized Controlled Case Series.

PubMed

Auld, Megan L; Johnston, Leanne M; Russo, Remo N; Moseley, G Lorimer

2017-10-01

This replicated randomized controlled crossover case series investigated the effect of mirror-based tactile and motor training on tactile registration and perception in children with unilateral cerebral palsy (UCP). Six children with UCP (6-18 years; median 10 years, five male, three-left hemiplegia, four-manual ability classification system (MACS) I, one MACS II and one MACS III) participated. They attended two 90-minute sessions - one of mirror-based training and one of standard practice, bimanual therapy - in alternated order. Tactile registration (Semmes Weinstein Monofilaments) and perception (double simultaneous or single-point localization) were assessed before and after each session. Change was estimated using reliable change index (RCI). Tactile perception improved in four participants (RCI > 1.75), with mirror-based training, but was unchanged with bimanual therapy (RCI < 1.0 for all participants). Neither intervention affected tactile registration. Mirror-based training demonstrates potential to improve tactile perception in children with UCP. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

High-resolution dynamic pressure sensor array based on piezo-phototronic effect tuned photoluminescence imaging.

PubMed

Peng, Mingzeng; Li, Zhou; Liu, Caihong; Zheng, Qiang; Shi, Xieqing; Song, Ming; Zhang, Yang; Du, Shiyu; Zhai, Junyi; Wang, Zhong Lin

2015-03-24

A high-resolution dynamic tactile/pressure display is indispensable to the comprehensive perception of force/mechanical stimulations such as electronic skin, biomechanical imaging/analysis, or personalized signatures. Here, we present a dynamic pressure sensor array based on pressure/strain tuned photoluminescence imaging without the need for electricity. Each sensor is a nanopillar that consists of InGaN/GaN multiple quantum wells. Its photoluminescence intensity can be modulated dramatically and linearly by small strain (0-0.15%) owing to the piezo-phototronic effect. The sensor array has a high pixel density of 6350 dpi and exceptional small standard deviation of photoluminescence. High-quality tactile/pressure sensing distribution can be real-time recorded by parallel photoluminescence imaging without any cross-talk. The sensor array can be inexpensively fabricated over large areas by semiconductor product lines. The proposed dynamic all-optical pressure imaging with excellent resolution, high sensitivity, good uniformity, and ultrafast response time offers a suitable way for smart sensing, micro/nano-opto-electromechanical systems.

Tactile display landing safety and precision improvements for the Space Shuttle

NASA Astrophysics Data System (ADS)

Olson, John M.

A tactile display belt using 24 electro-mechanical tactile transducers (tactors) was used to determine if a modified tactile display system, known as the Tactile Situation Awareness System (TSAS) improved the safety and precision of a complex spacecraft (i.e. the Space Shuttle Orbiter) in guided precision approaches and landings. The goal was to determine if tactile cues enhance safety and mission performance through reduced workload, increased situational awareness (SA), and an improved operational capability by increasing secondary cognitive workload capacity and human-machine interface efficiency and effectiveness. Using both qualitative and quantitative measures such as NASA's Justiz Numerical Measure and Synwork1 scores, an Overall Workload (OW) measure, the Cooper-Harper rating scale, and the China Lake Situational Awareness scale, plus Pre- and Post-Flight Surveys, the data show that tactile displays decrease OW, improve SA, counteract fatigue, and provide superior warning and monitoring capacity for dynamic, off-nominal, high concurrent workload scenarios involving complex, cognitive, and multi-sensory critical scenarios. Use of TSAS for maintaining guided precision approaches and landings was generally intuitive, reduced training times, and improved task learning effects. Ultimately, the use of a homogeneous, experienced, and statistically robust population of test pilots demonstrated that the use of tactile displays for Space Shuttle approaches and landings with degraded vehicle systems, weather, and environmental conditions produced substantial improvements in safety, consistency, reliability, and ease of operations under demanding conditions. Recommendations for further analysis and study are provided in order to leverage the results from this research and further explore the potential to reduce the risk of spaceflight and aerospace operations in general.

Blind Braille readers mislocate tactile stimuli.

PubMed

Sterr, Annette; Green, Lisa; Elbert, Thomas

2003-05-01

In a previous experiment, we observed that blind Braille readers produce errors when asked to identify on which finger of one hand a light tactile stimulus had occurred. With the present study, we aimed to specify the characteristics of this perceptual error in blind and sighted participants. The experiment confirmed that blind Braille readers mislocalised tactile stimuli more often than sighted controls, and that the localisation errors occurred significantly more often at the right reading hand than at the non-reading hand. Most importantly, we discovered that the reading fingers showed the smallest error frequency, but the highest rate of stimulus attribution. The dissociation of perceiving and locating tactile stimuli in the blind suggests altered tactile information processing. Neuroplasticity, changes in tactile attention mechanisms as well as the idea that blind persons may employ different strategies for tactile exploration and object localisation are discussed as possible explanations for the results obtained.

Depth Camera-Based 3D Hand Gesture Controls with Immersive Tactile Feedback for Natural Mid-Air Gesture Interactions

PubMed Central

Kim, Kwangtaek; Kim, Joongrock; Choi, Jaesung; Kim, Junghyun; Lee, Sangyoun

2015-01-01

Vision-based hand gesture interactions are natural and intuitive when interacting with computers, since we naturally exploit gestures to communicate with other people. However, it is agreed that users suffer from discomfort and fatigue when using gesture-controlled interfaces, due to the lack of physical feedback. To solve the problem, we propose a novel complete solution of a hand gesture control system employing immersive tactile feedback to the user's hand. For this goal, we first developed a fast and accurate hand-tracking algorithm with a Kinect sensor using the proposed MLBP (modified local binary pattern) that can efficiently analyze 3D shapes in depth images. The superiority of our tracking method was verified in terms of tracking accuracy and speed by comparing with existing methods, Natural Interaction Technology for End-user (NITE), 3D Hand Tracker and CamShift. As the second step, a new tactile feedback technology with a piezoelectric actuator has been developed and integrated into the developed hand tracking algorithm, including the DTW (dynamic time warping) gesture recognition algorithm for a complete solution of an immersive gesture control system. The quantitative and qualitative evaluations of the integrated system were conducted with human subjects, and the results demonstrate that our gesture control with tactile feedback is a promising technology compared to a vision-based gesture control system that has typically no feedback for the user's gesture inputs. Our study provides researchers and designers with informative guidelines to develop more natural gesture control systems or immersive user interfaces with haptic feedback. PMID:25580901

Depth camera-based 3D hand gesture controls with immersive tactile feedback for natural mid-air gesture interactions.

PubMed

Kim, Kwangtaek; Kim, Joongrock; Choi, Jaesung; Kim, Junghyun; Lee, Sangyoun

2015-01-08

Vision-based hand gesture interactions are natural and intuitive when interacting with computers, since we naturally exploit gestures to communicate with other people. However, it is agreed that users suffer from discomfort and fatigue when using gesture-controlled interfaces, due to the lack of physical feedback. To solve the problem, we propose a novel complete solution of a hand gesture control system employing immersive tactile feedback to the user's hand. For this goal, we first developed a fast and accurate hand-tracking algorithm with a Kinect sensor using the proposed MLBP (modified local binary pattern) that can efficiently analyze 3D shapes in depth images. The superiority of our tracking method was verified in terms of tracking accuracy and speed by comparing with existing methods, Natural Interaction Technology for End-user (NITE), 3D Hand Tracker and CamShift. As the second step, a new tactile feedback technology with a piezoelectric actuator has been developed and integrated into the developed hand tracking algorithm, including the DTW (dynamic time warping) gesture recognition algorithm for a complete solution of an immersive gesture control system. The quantitative and qualitative evaluations of the integrated system were conducted with human subjects, and the results demonstrate that our gesture control with tactile feedback is a promising technology compared to a vision-based gesture control system that has typically no feedback for the user's gesture inputs. Our study provides researchers and designers with informative guidelines to develop more natural gesture control systems or immersive user interfaces with haptic feedback.

Tactile Data Entry for Extravehicular Activity

NASA Technical Reports Server (NTRS)

Adams, Richard J.; Olowin, Aaron B.; Hannaford, Blake; Sands, O Scott

2012-01-01

In the task-saturated environment of extravehicular activity (EVA), an astronaut's ability to leverage suit-integrated information systems is limited by a lack of options for data entry. In particular, bulky gloves inhibit the ability to interact with standard computing interfaces such as a mouse or keyboard. This paper presents the results of a preliminary investigation into a system that permits the space suit gloves themselves to be used as data entry devices. Hand motion tracking is combined with simple finger gesture recognition to enable use of a virtual keyboard, while tactile feedback provides touch-based context to the graphical user interface (GUI) and positive confirmation of keystroke events. In human subject trials, conducted with twenty participants using a prototype system, participants entered text significantly faster with tactile feedback than without (p = 0.02). The results support incorporation of vibrotactile information in a future system that will enable full touch typing and general mouse interactions using instrumented EVA gloves.

The phase of prestimulus alpha oscillations affects tactile perception.

PubMed

Ai, Lei; Ro, Tony

2014-03-01

Previous studies have shown that neural oscillations in the 8- to 12-Hz range influence sensory perception. In the current study, we examined whether both the power and phase of these mu/alpha oscillations predict successful conscious tactile perception. Near-threshold tactile stimuli were applied to the left hand while electroencephalographic (EEG) activity was recorded over the contralateral right somatosensory cortex. We found a significant inverted U-shaped relationship between prestimulus mu/alpha power and detection rate, suggesting that there is an intermediate level of alpha power that is optimal for tactile perception. We also found a significant difference in phase angle concentration at stimulus onset that predicted whether the upcoming tactile stimulus was perceived or missed. As has been shown in the visual system, these findings suggest that these mu/alpha oscillations measured over somatosensory areas exert a strong inhibitory control on tactile perception and that pulsed inhibition by these oscillations shapes the state of brain activity necessary for conscious perception. They further suggest that these common phasic processing mechanisms across different sensory modalities and brain regions may reflect a common underlying encoding principle in perceptual processing that leads to momentary windows of perceptual awareness.

Tactile Instrument for Aviation

DTIC Science & Technology

2000-07-30

response times using 8 tactor locations was repeated with a dual memory /tracking task or an air combat simulation to evaluate the effectiveness of the...Global Positioning/Inertial Navigation System technologies into a single system for evaluation in an UH-60 Helicopter. A 10-event test operation was... evaluation of the following technology areas need to be pursued: • Integration of tactile instruments with helmet mounted displays and 3D audio displays

Tactile recognition and localization using object models: the case of polyhedra on a plane.

PubMed

Gaston, P C; Lozano-Perez, T

1984-03-01

This paper discusses how data from multiple tactile sensors may be used to identify and locate one object, from among a set of known objects. We use only local information from sensors: 1) the position of contact points and 2) ranges of surface normals at the contact points. The recognition and localization process is structured as the development and pruning of a tree of consistent hypotheses about pairings between contact points and object surfaces. In this paper, we deal with polyhedral objects constrained to lie on a known plane, i.e., having three degrees of positioning freedom relative to the sensors. We illustrate the performance of the algorithm by simulation.

Learning touch preferences with a tactile robot using dopamine modulated STDP in a model of insular cortex

PubMed Central

Chou, Ting-Shuo; Bucci, Liam D.; Krichmar, Jeffrey L.

2015-01-01

Neurorobots enable researchers to study how behaviors are produced by neural mechanisms in an uncertain, noisy, real-world environment. To investigate how the somatosensory system processes noisy, real-world touch inputs, we introduce a neurorobot called CARL-SJR, which has a full-body tactile sensory area. The design of CARL-SJR is such that it encourages people to communicate with it through gentle touch. CARL-SJR provides feedback to users by displaying bright colors on its surface. In the present study, we show that CARL-SJR is capable of learning associations between conditioned stimuli (CS; a color pattern on its surface) and unconditioned stimuli (US; a preferred touch pattern) by applying a spiking neural network (SNN) with neurobiologically inspired plasticity. Specifically, we modeled the primary somatosensory cortex, prefrontal cortex, striatum, and the insular cortex, which is important for hedonic touch, to process noisy data generated directly from CARL-SJR's tactile sensory area. To facilitate learning, we applied dopamine-modulated Spike Timing Dependent Plasticity (STDP) to our simulated prefrontal cortex, striatum, and insular cortex. To cope with noisy, varying inputs, the SNN was tuned to produce traveling waves of activity that carried spatiotemporal information. Despite the noisy tactile sensors, spike trains, and variations in subject hand swipes, the learning was quite robust. Further, insular cortex activities in the incremental pathway of dopaminergic reward system allowed us to control CARL-SJR's preference for touch direction without heavily pre-processed inputs. The emerged behaviors we found in this model match animal's behaviors wherein they prefer touch in particular areas and directions. Thus, the results in this paper could serve as an explanation on the underlying neural mechanisms for developing tactile preferences and hedonic touch. PMID:26257639

Audio-tactile integration and the influence of musical training.

PubMed

Kuchenbuch, Anja; Paraskevopoulos, Evangelos; Herholz, Sibylle C; Pantev, Christo

2014-01-01

Perception of our environment is a multisensory experience; information from different sensory systems like the auditory, visual and tactile is constantly integrated. Complex tasks that require high temporal and spatial precision of multisensory integration put strong demands on the underlying networks but it is largely unknown how task experience shapes multisensory processing. Long-term musical training is an excellent model for brain plasticity because it shapes the human brain at functional and structural levels, affecting a network of brain areas. In the present study we used magnetoencephalography (MEG) to investigate how audio-tactile perception is integrated in the human brain and if musicians show enhancement of the corresponding activation compared to non-musicians. Using a paradigm that allowed the investigation of combined and separate auditory and tactile processing, we found a multisensory incongruency response, generated in frontal, cingulate and cerebellar regions, an auditory mismatch response generated mainly in the auditory cortex and a tactile mismatch response generated in frontal and cerebellar regions. The influence of musical training was seen in the audio-tactile as well as in the auditory condition, indicating enhanced higher-order processing in musicians, while the sources of the tactile MMN were not influenced by long-term musical training. Consistent with the predictive coding model, more basic, bottom-up sensory processing was relatively stable and less affected by expertise, whereas areas for top-down models of multisensory expectancies were modulated by training.

Auditory-tactile echo-reverberating stuttering speech corrector

NASA Astrophysics Data System (ADS)

Kuniszyk-Jozkowiak, Wieslawa; Adamczyk, Bogdan

1997-02-01

The work presents the construction of a device, which transforms speech sounds into acoustical and tactile signals of echo and reverberation. Research has been done on the influence of the echo and reverberation, which are transmitted as acoustic and tactile stimuli, on speech fluency. Introducing the echo or reverberation into the auditory feedback circuit results in a reduction of stuttering. A bit less, but still significant corrective effects are observed while using the tactile channel for transmitting the signals. The use of joined auditory and tactile channels increases the effects of their corrective influence on the stutterers' speech. The results of the experiment justify the use of the tactile channel in the stutterers' therapy.

The role of tactile feedback in grip force during laparoscopic training tasks.

PubMed

Wottawa, Christopher R; Cohen, Jeremiah R; Fan, Richard E; Bisley, James W; Culjat, Martin O; Grundfest, Warren S; Dutson, Erik P

2013-04-01

Laparoscopic minimally invasive surgery has revolutionized surgical care by reducing trauma to the patient, thereby decreasing the need for medication and shortening recovery times. During open procedures, surgeons can directly feel tissue characteristics. However, in laparoscopic surgery, tactile feedback during grip is attenuated and limited to the resistance felt in the tool handle. Excessive grip force during laparoscopic surgery can lead to tissue damage. Providing additional supplementary tactile feedback may allow subjects to have better control of grip force and identification of tissue characteristics, potentially decreasing the learning curve associated with complex minimally invasive techniques. A tactile feedback system has been developed and integrated into a modified laparoscopic grasper that allows forces applied at the grasper tips to be felt by the surgeon's hands. In this study, 15 subjects (11 novices, 4 experts) were asked to perform single-handed peg transfers using these laparoscopic graspers in three trials (feedback OFF, ON, OFF). Peak and average grip forces (newtons) during each grip event were measured and compared using a Wilcoxon ranked test in which each subject served as his or her own control. After activating the tactile feedback system, the novice subject population showed significant decreases in grip force (p < 0.003). When the system was deactivated for the third trial, there were significant increases in grip force (p < 0.003). Expert subjects showed no significant improvements with the addition of tactile feedback (p > 0.05 in all cases). Supplementary tactile feedback helped novice subjects reduce grip force during the laparoscopic training task but did not offer improvements for the four expert subjects. This indicates that tactile feedback may be beneficial for laparoscopic training but has limited long-term use in the nonrobotic setting.

Virtual environment tactile system

DOEpatents

Renzi, Ronald

1996-01-01

A method for providing a realistic sense of touch in virtual reality by means of programmable actuator assemblies is disclosed. Each tactile actuator assembly consists of a number of individual actuators whose movement is controlled by a computer and associated drive electronics. When an actuator is energized, the rare earth magnet and the associated contactor, incorporated within the actuator, are set in motion by the opposing electromagnetic field of a surrounding coil. The magnet pushes the contactor forward to contact the skin resulting in the sensation of touch. When the electromagnetic field is turned off, the rare earth magnet and the contactor return to their neutral positions due to the magnetic equilibrium caused by the interaction with the ferrous outer sleeve. The small size and flexible nature of the actuator assemblies permit incorporation into a glove, boot or body suit. The actuator has additional applications, such as, for example, as an accelerometer, an actuator for precisely controlled actuations or to simulate the sensation of braille letters.

Mutual capacitance of liquid conductors in deformable tactile sensing arrays

NASA Astrophysics Data System (ADS)

Li, Bin; Fontecchio, Adam K.; Visell, Yon

2016-01-01

Advances in highly deformable electronics are needed in order to enable emerging categories of soft computing devices ranging from wearable electronics, to medical devices, and soft robotic components. The combination of highly elastic substrates with intrinsically stretchable conductors holds the promise of enabling electronic sensors that can conform to curved objects, reconfigurable displays, or soft biological tissues, including the skin. Here, we contribute sensing principles for tactile (mechanical image) sensors based on very low modulus polymer substrates with embedded liquid metal microfluidic arrays. The sensors are fabricated using a single-step casting method that utilizes fine nylon filaments to produce arrays of cylindrical channels on two layers. The liquid metal (gallium indium alloy) conductors that fill these channels readily adopt the shape of the embedding membrane, yielding levels of deformability greater than 400%, due to the use of soft polymer substrates. We modeled the sensor performance using electrostatic theory and continuum mechanics, yielding excellent agreement with experiments. Using a matrix-addressed capacitance measurement technique, we are able to resolve strain distributions with millimeter resolution over areas of several square centimeters.

Linkage between Free Exploratory Movements and Subjective Tactile Ratings.

PubMed

Yokosaka, Takumi; Kuroki, Scinob; Watanabe, Junji; Nishida, Shinya

2017-01-01

We actively move our hands and eyes when exploring the external world and gaining information about object's attributes. Previous studies showing that how we touch might be related to how we felt led us to consider whether we could decode observers' subjective tactile experiences only by analyzing their exploratory movements without explicitly asking how they perceived. However, in those studies, explicit judgment tasks were performed about specific tactile attributes that were prearranged by experimenters. Here, we systematically investigated whether exploratory movements can explain tactile ratings even when participants do not need to judge any tactile attributes. While measuring both hand and eye movements, we asked participants to touch materials freely without judging any specific tactile attributes (free-touch task) or to evaluate one of four tactile attributes (roughness, hardness, slipperiness, and temperature). We found that tactile ratings in the judgment tasks correlated with exploratory movements even in the free-touch task and that eye movements as well as hand movements correlated with tactile ratings. These results might open up the possibility of decoding tactile experiences by exploratory movements.

Making your skin crawl: The role of tactile sensitivity in disease avoidance.

PubMed

Hunt, David Francis; Cannell, Grace; Davenhill, Nicholas A; Horsford, Stephanie A; Fleischman, Diana S; Park, Justin H

2017-07-01

Mounting evidence indicates that animals, including humans, have evolved a behavioral disease-avoidance system designed to facilitate the detection and avoidance of sources of pathogens, and that this system interacts with physiological defenses. The skin acts as an important anatomical barrier, yet little research has investigated the role of tactile sensitivity in disease avoidance. Increased tactile sensitivity in the presence of potential sources of pathogens may facilitate prophylactic behaviors such as self-grooming. Across multiple studies, we tested the hypothesis that the induction of disgust-the key emotion underlying disease avoidance-may lead to greater tactile sensitivity compared to control conditions. A nonsignificant trend was found in a pilot study, which was replicated (and found to be significant) in Studies 1 and 2. To our knowledge, these results are the first to demonstrate disgust-induced changes in tactile sensitivity, and they contribute to the growing literature on the integrated evolved defenses against infectious disease. Copyright © 2017 Elsevier B.V. All rights reserved.

A controllable tactile device for human-like tissue realization using smart magneto-rheological fluids: fabrication and modeling

NASA Astrophysics Data System (ADS)

Cha, Seung-Woo; Kang, Seok-Rae; Hwang, Yong-Hoon; Oh, Jong-Seok; Choi, Seung-Bok

2018-06-01

This paper proposes a new tactile device to realize the force of human-like organs using the viscoelastic property by combing a smart magneto-rheological (MR) fluid with a sponge (MR sponge in short). The effectiveness of the sensor is validated through the comparison of the force obtained through measurement and the proposed prediction model. As the first step, a conventional standard linear solid model is adopted to independently investigate the force characteristics of MR fluid and sponge. Force is measured using a 3-axis robot with a force sensor to obtain certain properties of MR fluid and sponge. In addition, to show that the proposed MR sponge can realize the force of human-like tissues, experiments are performed using three specimens, i.e., porcine heart, lung, and liver. Subsequently, a quasi-static model for predicting the field-dependent force of the MR sponge is formulated using empirical values. It is demonstrated through comparison that the proposed force model can accurately predict the force of the specimens without significant error. In addition, a psychophysical test is carried out by ordinary subjects to validate the effectiveness of the proposed tactile device. Results show that the MR sponge tactile device can easily produce various levels of the force of human-like tissues, such as the liver and lung of the porcine, by controlling input current.

A flexible slip sensor using triboelectric nanogenerator approach

NASA Astrophysics Data System (ADS)

Wang, Xudong; Liang, Jiaming; Xiao, Yuxiang; Wu, Yichuan; Deng, Yang; Wang, Xiaohao; Zhang, Min

2018-03-01

With the rapid development of robotic technology, tactile sensors for robots have gained great attention from academic and industry researchers. Tactile sensors for slip detection are essential for human-like steady control in dexterous robot hand. In this paper, we propose and demonstrate a flexible slip sensor based on triboelectric nanogenerator with a seesaw structure. The sensor is composed of two porous PDMS layers separated by an inverted trapezoid structure with a height of 500 μm. In order to customize the sensitivity of the sensor, porous PDMS was fabricated by mixing PDMS with deionized water thoroughly and then removing water with heat. Laser-induced porous graphene and aluminium are served as the pair of contact materials. To detect slip from different directions, two sets of the electrode pair were used. Experimental results show a distinct difference between static state and the moment when a slip happens was detected. In addition, the output voltage of the sensors increased as the increase of slip velocity from 0.25 mm/s to 2.5 mm/s. The flexible slip sensor proposed here shows the potential applications in smart robotics and prosthesis.

Meet our Neighbours - a tactile experience

NASA Astrophysics Data System (ADS)

Canas, L.; Lobo Correia, A.

2013-09-01

Planetary science is a key field in astronomy that draws lots of attention and that engages large amounts of enthusiasts. On its essence, it is a visual science and the current resources and activities for the inclusion of visually impaired children, although increasing, are still costly and somewhat scarce. Therefore there is a paramount need to develop more low cost resources in order to provide experiences that can reach all, even the more socially deprived communities. "Meet our neighbours!-a tactile experience", plans to promote and provide inclusion activities for visually impaired children and their non-visually impaired peers through the use of astronomy hands-on low cost activities. Is aimed for children from the ages of 6 to 12 years old and produce data set 13 tactile images of the main objects of the Solar System that can be used in schools, science centres and outreach associations. Accessing several common problems through tactile resources, with this project we present ways to successfully provide low cost solutions (avoiding the expensive tactile printing costs), promote inclusion and interactive hands-on activities for visually impaired children and their non-visually impaired peers and create dynamic interactions based on oral knowledge transmission between them. Here we describe the process of implementing such initiative near target communities: establishing a bridge between scientists, children and teachers. The struggles and challenges perceived during the project and the enrichment experience of engaging astronomy with these specific groups, broadening horizons in an overall experience accessible to all.

Exploration of the Effectiveness of Tactile Methods

ERIC Educational Resources Information Center

Aldajani, Neda F.

2016-01-01

This paper introduces the tactile method and aims to explore the effectiveness of using tactile methods with students who are blind and visually impaired. Although there was limited research about using this strategy, all of the research agrees that using tactile is one of the best ways for students who are blind and visually impaired to be…

Merkel disc is a serotonergic synapse in the epidermis for transmitting tactile signals in mammals.

PubMed

Chang, Weipang; Kanda, Hirosato; Ikeda, Ryo; Ling, Jennifer; DeBerry, Jennifer J; Gu, Jianguo G

2016-09-13

The evolution of sensory systems has let mammals develop complicated tactile end organs to enable sophisticated sensory tasks, including social interaction, environmental exploration, and tactile discrimination. The Merkel disc, a main type of tactile end organ consisting of Merkel cells (MCs) and Aβ-afferent endings, are highly abundant in fingertips, touch domes, and whisker hair follicles of mammals. The Merkel disc has high tactile acuity for an object's physical features, such as texture, shape, and edges. Mechanisms underlying the tactile function of Merkel discs are obscured as to how MCs transmit tactile signals to Aβ-afferent endings leading to tactile sensations. Using mouse whisker hair follicles, we show herein that tactile stimuli are transduced by MCs into excitatory signals that trigger vesicular serotonin release from MCs. We identify that both ionotropic and metabotropic 5-hydroxytryptamine (5-HT) receptors are expressed on whisker Aβ-afferent endings and that their activation by serotonin released from MCs initiates Aβ-afferent impulses. Moreover, we demonstrate that these ionotropic and metabotropic 5-HT receptors have a synergistic effect that is critical to both electrophysiological and behavioral tactile responses. These findings elucidate that the Merkel disc is a unique serotonergic synapse located in the epidermis and plays a key role in tactile transmission. The epidermal serotonergic synapse may have important clinical implications in sensory dysfunctions, such as the loss of tactile sensitivity and tactile allodynia seen in patients who have diabetes, inflammatory diseases, and undergo chemotherapy. It may also have implications in the exaggerated tactile sensations induced by recreational drugs that act on serotoninergic synapses.

Deployment and evaluation of a dual-sensor autofocusing method for on-machine measurement of patterns of small holes on freeform surfaces.

PubMed

Chen, Xiaomei; Longstaff, Andrew; Fletcher, Simon; Myers, Alan

2014-04-01

This paper presents and evaluates an active dual-sensor autofocusing system that combines an optical vision sensor and a tactile probe for autofocusing on arrays of small holes on freeform surfaces. The system has been tested on a two-axis test rig and then integrated onto a three-axis computer numerical control (CNC) milling machine, where the aim is to rapidly and controllably measure the hole position errors while the part is still on the machine. The principle of operation is for the tactile probe to locate the nominal positions of holes, and the optical vision sensor follows to focus and capture the images of the holes. The images are then processed to provide hole position measurement. In this paper, the autofocusing deviations are analyzed. First, the deviations caused by the geometric errors of the axes on which the dual-sensor unit is deployed are estimated to be 11 μm when deployed on a test rig and 7 μm on the CNC machine tool. Subsequently, the autofocusing deviations caused by the interaction of the tactile probe, surface, and small hole are mathematically analyzed and evaluated. The deviations are a result of the tactile probe radius, the curvatures at the positions where small holes are drilled on the freeform surface, and the effect of the position error of the hole on focusing. An example case study is provided for the measurement of a pattern of small holes on an elliptical cylinder on the two machines. The absolute sum of the autofocusing deviations is 118 μm on the test rig and 144 μm on the machine tool. This is much less than the 500 μm depth of field of the optical microscope. Therefore, the method is capable of capturing a group of clear images of the small holes on this workpiece for either implementation.

Braille in the Sighted: Teaching Tactile Reading to Sighted Adults.

PubMed

Bola, Łukasz; Siuda-Krzywicka, Katarzyna; Paplińska, Małgorzata; Sumera, Ewa; Hańczur, Paweł; Szwed, Marcin

2016-01-01

Blind people are known to have superior perceptual abilities in their remaining senses. Several studies suggest that these enhancements are dependent on the specific experience of blind individuals, who use those remaining senses more than sighted subjects. In line with this view, sighted subjects, when trained, are able to significantly progress in relatively simple tactile tasks. However, the case of complex tactile tasks is less obvious, as some studies suggest that visual deprivation itself could confer large advantages in learning them. It remains unclear to what extent those complex skills, such as braille reading, can be learnt by sighted subjects. Here we enrolled twenty-nine sighted adults, mostly braille teachers and educators, in a 9-month braille reading course. At the beginning of the course, all subjects were naive in tactile braille reading. After the course, almost all were able to read whole braille words at a mean speed of 6 words-per-minute. Subjects with low tactile acuity did not differ significantly in braille reading speed from the rest of the group, indicating that low tactile acuity is not a limiting factor for learning braille, at least at this early stage of learning. Our study shows that most sighted adults can learn whole-word braille reading, given the right method and a considerable amount of motivation. The adult sensorimotor system can thus adapt, to some level, to very complex tactile tasks without visual deprivation. The pace of learning in our group was comparable to congenitally and early blind children learning braille in primary school, which suggests that the blind's mastery of complex tactile tasks can, to a large extent, be explained by experience-dependent mechanisms.

Braille in the Sighted: Teaching Tactile Reading to Sighted Adults

PubMed Central

Bola, Łukasz; Siuda-Krzywicka, Katarzyna; Paplińska, Małgorzata; Sumera, Ewa; Hańczur, Paweł; Szwed, Marcin

2016-01-01

Blind people are known to have superior perceptual abilities in their remaining senses. Several studies suggest that these enhancements are dependent on the specific experience of blind individuals, who use those remaining senses more than sighted subjects. In line with this view, sighted subjects, when trained, are able to significantly progress in relatively simple tactile tasks. However, the case of complex tactile tasks is less obvious, as some studies suggest that visual deprivation itself could confer large advantages in learning them. It remains unclear to what extent those complex skills, such as braille reading, can be learnt by sighted subjects. Here we enrolled twenty-nine sighted adults, mostly braille teachers and educators, in a 9-month braille reading course. At the beginning of the course, all subjects were naive in tactile braille reading. After the course, almost all were able to read whole braille words at a mean speed of 6 words-per-minute. Subjects with low tactile acuity did not differ significantly in braille reading speed from the rest of the group, indicating that low tactile acuity is not a limiting factor for learning braille, at least at this early stage of learning. Our study shows that most sighted adults can learn whole-word braille reading, given the right method and a considerable amount of motivation. The adult sensorimotor system can thus adapt, to some level, to very complex tactile tasks without visual deprivation. The pace of learning in our group was comparable to congenitally and early blind children learning braille in primary school, which suggests that the blind’s mastery of complex tactile tasks can, to a large extent, be explained by experience-dependent mechanisms. PMID:27187496

A Tactile Carina Nebula

NASA Astrophysics Data System (ADS)

Grice, Noreen A.; Mutchler, M.

2010-01-01

Astronomy was once considered a science restricted to fully sighted participants. But in the past two decades, accessible books with large print/Braille and touchable pictures have brought astronomy and space science to the hands and mind's eye of students, regardless of their visual ability. A new universally-designed tactile image featuring the Hubble mosaic of the Carina Nebula is being presented at this conference. The original dataset was obtained with Hubble's Advanced Camera for Surveys (ACS) hydrogen-alpha filter in 2005. It became an instant icon after being infused with additional color information from ground-based CTIO data, and released as Hubble's 17th anniversary image. Our tactile Carina Nebula promotes multi-mode learning about the entire life-cycle of stars, which is dramatically illustrated in this Hubble mosaic. When combined with descriptive text in print and Braille, the visual and tactile components seamlessly reach both sighted and blind populations. Specific touchable features of the tactile image identify the shapes and orientations of objects in the Carina Nebula that include star-forming regions, jets, pillars, dark and light globules, star clusters, shocks/bubbles, the Keyhole Nebula, and stellar death (Eta Carinae). Visit our poster paper to touch the Carina Nebula!

A haptic sensor-actor-system based on ultrasound elastography and electrorheological fluids for virtual reality applications in medicine.

PubMed

Khaled, W; Ermert, H; Bruhns, O; Boese, H; Baumann, M; Monkman, G J; Egersdoerfer, S; Meier, A; Klein, D; Freimuth, H

2003-01-01

Mechanical properties of biological tissue represent important diagnostic information and are of histological relevance (hard lesions, "nodes" in organs: tumors; calcifications in vessels: arteriosclerosis). The problem is, that such information is usually obtained by digital palpation only, which is limited with respect to sensitivity. It requires intuitive assessment and does not allow quantitative documentation. A suitable sensor is required for quantitative detection of mechanical tissue properties. On the other hand, there is also some need for a realistic mechanical display of those tissue properties. Suitable actuator arrays with high spatial resolution and real-time capabilities are required operating in a haptic sensor actuator system with different applications. The sensor system uses real time ultrasonic elastography whereas the tactile actuator is based on electrorheological fluids. Due to their small size the actuator array elements have to be manufactured by micro-mechanical production methods. In order to supply the actuator elements with individual high voltages a sophisticated switching and control concept have been designed. This haptic system has the potential of inducing real time substantial forces, using a compact lightweight mechanism which can be applied to numerous areas including intraoperative navigation, telemedicine, teaching, space and telecommunication.

Tactile communication.

DOT National Transportation Integrated Search

1962-05-01

Tactile communication presents a relatively unexploited channel of information transmission in the field of aviation. Visual and auditory input channels frequently reach an information saturation point during various flight operations. A cutaneous co...

Viewing the body modulates tactile receptive fields.

PubMed

Haggard, Patrick; Christakou, Anastasia; Serino, Andrea

2007-06-01

Tactile discrimination performance depends on the receptive field (RF) size of somatosensory cortical (SI) neurons. Psychophysical masking effects can reveal the RF of an idealized "virtual" somatosensory neuron. Previous studies show that top-down factors strongly affect tactile discrimination performance. Here, we show that non-informative vision of the touched body part influences tactile discrimination by modulating tactile RFs. Ten subjects performed spatial discrimination between touch locations on the forearm. Performance was improved when subjects saw their forearm compared to viewing a neutral object in the same location. The extent of visual information was relevant, since restricted view of the forearm did not have this enhancing effect. Vibrotactile maskers were placed symmetrically on either side of the tactile target locations, at two different distances. Overall, masking significantly impaired discrimination performance, but the spatial gradient of masking depended on what subjects viewed. Viewing the body reduced the effect of distant maskers, but enhanced the effect of close maskers, as compared to viewing a neutral object. We propose that viewing the body improves functional touch by sharpening tactile RFs in an early somatosensory map. Top-down modulation of lateral inhibition could underlie these effects.

Thinking about touch facilitates tactile but not auditory processing.

PubMed

Anema, Helen A; de Haan, Alyanne M; Gebuis, Titia; Dijkerman, H Chris

2012-05-01

Mental imagery is considered to be important for normal conscious experience. It is most frequently investigated in the visual, auditory and motor domain (imagination of movement), while the studies on tactile imagery (imagination of touch) are scarce. The current study investigated the effect of tactile and auditory imagery on the left/right discriminations of tactile and auditory stimuli. In line with our hypothesis, we observed that after tactile imagery, tactile stimuli were responded to faster as compared to auditory stimuli and vice versa. On average, tactile stimuli were responded to faster as compared to auditory stimuli, and stimuli in the imagery condition were on average responded to slower as compared to baseline performance (left/right discrimination without imagery assignment). The former is probably due to the spatial and somatotopic proximity of the fingers receiving the taps and the thumbs performing the response (button press), the latter to a dual task cost. Together, these results provide the first evidence of a behavioural effect of a tactile imagery assignment on the perception of real tactile stimuli.

Tactility and the body in early Chinese medicine.

PubMed

Hsu, Elisabeth

2005-03-01

If visual inspection of corpses was central to the development of anatomy in modern Europe, one may ask which of the senses was important for the emergence of the predominant currents of scholarly medical knowledge and practice in third- and second-century B.C.E. China? This article argues that it was tactile perception prompted by a tactile exploration of living bodies. The evidence, derived from a close reading of the Mawangdui medical manuscripts, the 105th chapter of the Records of the Historian, and selected passages from the Huang Di's Inner Canon, points to three important trends: first, the tactile exploration of the extremities led to a rich vocabulary of compound words for pain as localized in specific body parts; second, the tactile exploration of the mai gave rise to an even richer vocabulary on qualities of touch in pulse diagnostics; and third, the tactile exploration of the abdomen led to the assessment of the quality of the internal viscera with words that generally were used for describing the tactile quality of skin and flesh. This finding may appear surprising in the light of later developments during the dynastic history of Chinese medicine where tactile exploration of abdomen and extremities would appear unseemly. The author suggests that extensive tactile explorations of the body were possible before Confucius' teachings became a predominant aspect of state ideology.

Virtual environment tactile system

DOEpatents

Renzi, R.

1996-12-10

A method for providing a realistic sense of touch in virtual reality by means of programmable actuator assemblies is disclosed. Each tactile actuator assembly consists of a number of individual actuators whose movement is controlled by a computer and associated drive electronics. When an actuator is energized, the rare earth magnet and the associated contactor, incorporated within the actuator, are set in motion by the opposing electromagnetic field of a surrounding coil. The magnet pushes the contactor forward to contact the skin resulting in the sensation of touch. When the electromagnetic field is turned off, the rare earth magnet and the contactor return to their neutral positions due to the magnetic equilibrium caused by the interaction with the ferrous outer sleeve. The small size and flexible nature of the actuator assemblies permit incorporation into a glove, boot or body suit. The actuator has additional applications, such as, for example, as an accelerometer, an actuator for precisely controlled actuations or to simulate the sensation of braille letters. 28 figs.

Biotactile Sensors: Self-Powered Electronic Skin with Biotactile Selectivity (Adv. Mater. 18/2016).

PubMed

Hu, Kesong; Xiong, Rui; Guo, Hengyu; Ma, Ruilong; Zhang, Shuaidi; Wang, Zhong Lin; Tsukruk, Vladimir V

2016-05-01

On page 3549, V. V. Tsukruk and co-workers develop self-powered ultrathin flexible films for bio-tactile detection. Graphene oxide materials are engineered for robust self-powered tactile sensing applications harnessing their electrochemical reactivity. The simple quadruple electronic skin sensor can recognize nine spatial bio-tactile positions with high sensitivity and selectivity-an approach that can be expanded towards large-area flexible skin arrays. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of microsized slip sensors using dielectric elastomer for incipient slippage

NASA Astrophysics Data System (ADS)

Hwang, Do-Yeon; Kim, Baek-chul; Cho, Han-Jeong; Li, Zhengyuan; Lee, Youngkwan; Nam, Jae-Do; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, J. C.

2014-04-01

A humanoid robot hand has received significant attention in various fields of study. In terms of dexterous robot hand, slip detecting tactile sensor is essential to grasping objects safely. Moreover, slip sensor is useful in robotics and prosthetics to improve precise control during manipulation tasks. In this paper, sensor based-human biomimetic structure is fabricated. We reported a resistance tactile sensor that enables to detect a slip on the surface of sensor structure. The resistance slip sensor that the novel developed uses acrylonitrile-butadiene rubber (NBR) as a dielectric substrate and carbon particle as an electrode material. The presented sensor device in this paper has fingerprint-like structures that are similar with the role of the human's finger print. It is possible to measure the slip as the structure of sensor makes a deformation and it changes the resistance through forming a new conductive route. To verify effectiveness of the proposed slip detection, experiment using prototype of resistance slip sensor is conducted with an algorithm to detect slip and slip was successfully detected. In this paper, we will discuss the slip detection properties so four sensor and detection principle.

An Adaptation-Induced Repulsion Illusion in Tactile Spatial Perception

PubMed Central

Li, Lux; Chan, Arielle; Iqbal, Shah M.; Goldreich, Daniel

2017-01-01

Following focal sensory adaptation, the perceived separation between visual stimuli that straddle the adapted region is often exaggerated. For instance, in the tilt aftereffect illusion, adaptation to tilted lines causes subsequently viewed lines with nearby orientations to be perceptually repelled from the adapted orientation. Repulsion illusions in the nonvisual senses have been less studied. Here, we investigated whether adaptation induces a repulsion illusion in tactile spatial perception. In a two-interval forced-choice task, participants compared the perceived separation between two point-stimuli applied on the forearms successively. Separation distance was constant on one arm (the reference) and varied on the other arm (the comparison). In Experiment 1, we took three consecutive baseline measurements, verifying that in the absence of manipulation, participants’ distance perception was unbiased across arms and stable across experimental blocks. In Experiment 2, we vibrated a region of skin on the reference arm, verifying that this focally reduced tactile sensitivity, as indicated by elevated monofilament detection thresholds. In Experiment 3, we applied vibration between the two reference points in our distance perception protocol and discovered that this caused an illusory increase in the separation between the points. We conclude that focal adaptation induces a repulsion aftereffect illusion in tactile spatial perception. The illusion provides clues as to how the tactile system represents spatial information. The analogous repulsion aftereffects caused by adaptation in different stimulus domains and sensory systems may point to fundamentally similar strategies for dynamic sensory coding. PMID:28701936

Audio-Visual, Visuo-Tactile and Audio-Tactile Correspondences in Preschoolers.

PubMed

Nava, Elena; Grassi, Massimo; Turati, Chiara

2016-01-01

Interest in crossmodal correspondences has recently seen a renaissance thanks to numerous studies in human adults. Yet, still very little is known about crossmodal correspondences in children, particularly in sensory pairings other than audition and vision. In the current study, we investigated whether 4-5-year-old children match auditory pitch to the spatial motion of visual objects (audio-visual condition). In addition, we investigated whether this correspondence extends to touch, i.e., whether children also match auditory pitch to the spatial motion of touch (audio-tactile condition) and the spatial motion of visual objects to touch (visuo-tactile condition). In two experiments, two different groups of children were asked to indicate which of two stimuli fitted best with a centrally located third stimulus (Experiment 1), or to report whether two presented stimuli fitted together well (Experiment 2). We found sensitivity to the congruency of all of the sensory pairings only in Experiment 2, suggesting that only under specific circumstances can these correspondences be observed. Our results suggest that pitch-height correspondences for audio-visual and audio-tactile combinations may still be weak in preschool children, and speculate that this could be due to immature linguistic and auditory cues that are still developing at age five.

Mutual capacitance of liquid conductors in deformable tactile sensing arrays

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

Li, Bin; Fontecchio, Adam K.; Visell, Yon

2016-01-04

Advances in highly deformable electronics are needed in order to enable emerging categories of soft computing devices ranging from wearable electronics, to medical devices, and soft robotic components. The combination of highly elastic substrates with intrinsically stretchable conductors holds the promise of enabling electronic sensors that can conform to curved objects, reconfigurable displays, or soft biological tissues, including the skin. Here, we contribute sensing principles for tactile (mechanical image) sensors based on very low modulus polymer substrates with embedded liquid metal microfluidic arrays. The sensors are fabricated using a single-step casting method that utilizes fine nylon filaments to produce arraysmore » of cylindrical channels on two layers. The liquid metal (gallium indium alloy) conductors that fill these channels readily adopt the shape of the embedding membrane, yielding levels of deformability greater than 400%, due to the use of soft polymer substrates. We modeled the sensor performance using electrostatic theory and continuum mechanics, yielding excellent agreement with experiments. Using a matrix-addressed capacitance measurement technique, we are able to resolve strain distributions with millimeter resolution over areas of several square centimeters.« less

Tactile Gloves for Autonomous Grasping With the NASA/DARPA Robonaut

NASA Technical Reports Server (NTRS)

Martin, T. B.; Ambrose, R. O.; Diftler, M. A.; Platt, R., Jr.; Butzer, M. J.

2004-01-01

Tactile data from rugged gloves are providing the foundation for developing autonomous grasping skills for the NASA/DARPA Robonaut, a dexterous humanoid robot. These custom gloves compliment the human like dexterity available in the Robonaut hands. Multiple versions of the gloves are discussed, showing a progression in using advanced materials and construction techniques to enhance sensitivity and overall sensor coverage. The force data provided by the gloves can be used to improve dexterous, tool and power grasping primitives. Experiments with the latest gloves focus on the use of tools, specifically a power drill used to approximate an astronaut's torque tool.

The Design of Tactile Thematic Symbols

ERIC Educational Resources Information Center

Lawrence, Megan M.; Lobben, Amy K.

2011-01-01

The study reported here investigated the design and legibility of tactile thematic maps, focusing on symbolization and the comprehension of spatial patterns on the maps. The results indicate that discriminable and effective tactile thematic maps can be produced using classed data with a microcapsule paper production method. The participants…

Misunderstanding and Repair in Tactile Auslan

ERIC Educational Resources Information Center

Willoughby, Louisa; Manns, Howard; Iwasaki, Shimako; Bartlett, Meredith

2014-01-01

This article discusses ways in which misunderstandings arise in Tactile Australian Sign Language (Tactile Auslan) and how they are resolved. Of particular interest are the similarities to and differences from the same processes in visually signed and spoken conversation. This article draws on detailed conversation analysis (CA) and demonstrates…

Crossmodal Congruency Benefits of Tactile and Visual Signalling

DTIC Science & Technology

2013-11-12

modal information format seemed to produce faster and more accurate performance. The question of learning complex tactile communication signals...SECURITY CLASSIFICATION OF: We conducted an experiment in which tactile messages were created based on five common military arm and hand signals. We...compared response times and accuracy rates of novice individuals responding to visual and tactile representations of these messages, which were

Observing the Use of Tactile Schedules

ERIC Educational Resources Information Center

Aasen, Gro; Naerland, Terje

2014-01-01

This article explores the use of tactile schedules in a heterogeneous sample of children with congenital blindness and varying degrees of additional disabilities. Basic conditions for the use of tactile schedules are proposed and discussed. Child behaviour indicative of some particular functions that can be attained with the use of tactile…

Enhanced tactile encoding and memory recognition in congenital blindness.

PubMed

D'Angiulli, Amedeo; Waraich, Paul

2002-06-01

Several behavioural studies have shown that early-blind persons possess superior tactile skills. Since neurophysiological data show that early-blind persons recruit visual as well as somatosensory cortex to carry out tactile processing (cross-modal plasticity), blind persons' sharper tactile skills may be related to cortical re-organisation resulting from loss of vision early in their life. To examine the nature of blind individuals' tactile superiority and its implications for cross-modal plasticity, we compared the tactile performance of congenitally totally blind, low-vision and sighted children on raised-line picture identification test and re-test, assessing effects of task familiarity, exploratory strategy and memory recognition. What distinguished the blind from the other children was higher memory recognition and higher tactile encoding associated with efficient exploration. These results suggest that enhanced perceptual encoding and recognition memory may be two cognitive correlates of cross-modal plasticity in congenital blindness.

A dense array stimulator to generate arbitrary spatio-temporal tactile stimuli

PubMed Central

Killebrew, Justin H.; Bensmaïa, Sliman J.; Dammann, John F.; Denchev, Peter; Hsiao, Steven S.; Craig, James C.

2007-01-01

The generation and presentation of tactile stimuli presents a unique challenge. Unlike vision and audition, in which standard equipment such as monitors and audio systems can be used for most experiments, tactile stimuli and/or stimulators often have to be tailor-made for a given study. Here, we present a novel tactile stimulator designed to present arbitrary spatio-temporal stimuli to the skin. The stimulator consists of 400 pins, arrayed over a 1 cm2 area, each under independent computer control. The dense array allows for an unprecedented number of stimuli to be presented within an experimental session (e.g., up to 1200 stimuli per minute) and for stimuli to be generated adaptively. The stimulator can be used in a variety of modes and can deliver indented and scanned patterns as well as stimuli defined by mathematical spatio-temporal functions (e.g., drifting sinusoids). We describe the hardware and software of the system, and discuss previous and prospective applications. PMID:17134760

Exploring Tactile Perceptual Dimensions Using Materials Associated with Sensory Vocabulary.

PubMed

Sakamoto, Maki; Watanabe, Junji

2017-01-01

Considering tactile sensation when designing products is important because the decision to purchase often depends on how products feel. Numerous psychophysical studies have attempted to identify important factors that describe tactile perceptions. However, the numbers and types of major tactile dimensions reported in previous studies have varied because of differences in materials used across experiments. To obtain a more complete picture of perceptual space with regard to touch, our study focuses on using vocabulary that expresses tactile sensations as a guiding principle for collecting material samples because these types of words are expected to cover all the basic categories within tactile perceptual space. We collected 120 materials based on a variety of Japanese sound-symbolic words for tactile sensations, and used the materials to examine tactile perceptual dimensions and their associations with affective evaluations. Analysis revealed six major dimensions: "Affective evaluation and Friction," "Compliance," "Surface," "Volume," "Temperature," and "Naturalness." These dimensions include four factors that previous studies have regarded as fundamental, as well as two new factors: "Volume" and "Naturalness." Additionally, we showed that "Affective evaluation" is more closely related to the "Friction" component (slipperiness and dryness) than to other tactile perceptual features. Our study demonstrates that using vocabulary could be an effective method for selecting material samples to explore tactile perceptual space.

Optical versus tactile geometry measurement: alternatives or counterparts

NASA Astrophysics Data System (ADS)

Lehmann, Peter

2003-05-01

This contribution deals with measuring strategies and methods for the determination of several geometrical features, covering the surface micro-topography and the form of mechanical objects. The measuring principles used in optical surface metrology include optical focusing profilers, confocal point measuring and areal measuring sensors as well as interferometrical principles such as white light interferometry and speckle techniques. In comparison with stylus instruments optical techniques provide certain advantages such as a fast data acquisition, in-process applicability or contactless measurement. However, the frequency response characteristics of optical and tactile measurement differ significantly. In addition, optical sensors are commonly more influenced by critical geometrical conditions and optical properties of an object. For precise form measurement mechanical instruments dominate till now. One reason for this may be, that commonly the complete 360 degrees geometry of the measuring object has to be analyzed. Another point is that optical principles such as form measuring interferometry fail in cases of complex object geometry or rougher object surfaces. Other methods, e.g. fringe projection or digital holography, till now do not meet the accuracy demands of precision engineered workpieces. Hence, a combination of mechanical concepts and optical sensors represents an interesting potential for current and future measuring tasks, which require high accuracy and maximum flexibility.

Characterization of a compliant multi-layer system for tactile sensing with enhanced sensitivity and range

NASA Astrophysics Data System (ADS)

Chen, Ying; Yu, Miao; Bruck, Hugh A.; Smela, Elisabeth

2018-06-01

To allow robots to interact with humans via touch, new sensing concepts are needed that can detect a wide range of potential interactions and cover the body of a robot. In this paper, a skin-inspired multi-layer tactile sensing architecture is presented and characterized. The structure consists of stretchable piezoresistive strain-sensing layers over foam layers of different stiffness, allowing for both sufficient sensitivity and pressure range for human contacts. Strip-shaped sensors were used in this architecture to produce a deformation response proportional to pressure. The roles of the foam layers were elucidated by changing their stiffness and thickness, allowing the development of a geometric model to account for indenter interactions with the structure. The advantage of this architecture over other approaches is the ability to easily tune performance by adjusting the stiffness or thickness of the foams to tailor the response for different applications. Since viscoelastic materials were used, the temporal effects were also investigated.

Tactile Robotic Topographical Mapping Without Force or Contact Sensors

NASA Technical Reports Server (NTRS)

Burke, Kevin; Melko, Joseph; Krajewski, Joel; Cady, Ian

2008-01-01

A method of topographical mapping of a local solid surface within the range of motion of a robot arm is based on detection of contact between the surface and the end effector (the fixture or tool at the tip of the robot arm). The method was conceived to enable mapping of local terrain by an exploratory robot on a remote planet, without need to incorporate delicate contact switches, force sensors, a vision system, or other additional, costly hardware. The method could also be used on Earth for determining the size and shape of an unknown surface in the vicinity of a robot, perhaps in an unanticipated situation in which other means of mapping (e.g., stereoscopic imaging or laser scanning with triangulation) are not available. The method uses control software modified to utilize the inherent capability of the robotic control system to measure the joint positions, the rates of change of the joint positions, and the electrical current demanded by the robotic arm joint actuators. The system utilizes these coordinate data and the known robot-arm kinematics to compute the position and velocity of the end effector, move the end effector along a specified trajectory, place the end effector at a specified location, and measure the electrical currents in the joint actuators. Since the joint actuator current is approximately proportional to the actuator forces and torques, a sudden rise in joint current, combined with a slowing of the joint, is a possible indication of actuator stall and surface contact. Hence, even though the robotic arm is not equipped with contact sensors, it is possible to sense contact (albeit with reduced sensitivity) as the end effector becomes stalled against a surface that one seeks to measure.

Magneto-inductive skin sensor for robot collision avoidance: A new development

NASA Technical Reports Server (NTRS)

Chauhan, D. S.; Dehoff, Paul H.

1989-01-01

Safety is a primary concern for robots operating in space. The tri-mode sensor addresses that concern by employing a collision avoidance/management skin around the robot arms. This rf-based skin sensor is at present a dual mode (proximity and tactile). The third mode, pyroelectric, will complement the other two. The proximity mode permits the robot to sense an intruding object, to range the object, and to detect the edges of the object. The tactile mode permits the robot to sense when it has contacted an object, where on the arm it has made contact, and provides a three-dimensional image of the shape of the contact impression. The pyroelectric mode will be added to permit the robot arm to detect the proximity of a hot object and to add sensing redundancy to the two other modes. The rf-modes of the sensing skin are presented. These modes employ a highly efficient magnetic material (amorphous metal) in a sensing technique. This results in a flexible sensor array which uses a primarily inductive configuration to permit both capacitive and magnetoinductive sensing of object; thus optimizing performance in both proximity and tactile modes with the same sensing skin. The fundamental operating principles, design particulars, and theoretical models are provided to aid in the description and understanding of this sensor. Test results are also given.

Virtual surface characteristics of a tactile display using magneto-rheological fluids.

PubMed

Lee, Chul-Hee; Jang, Min-Gyu

2011-01-01

Virtual surface characteristics of tactile displays are investigated to characterize the feeling of human touch for a haptic interface application. In order to represent the tactile feeling, a prototype tactile display incorporating Magneto-Rheological (MR) fluid has been developed. Tactile display devices simulate the finger's skin to feel the sensations of contact such as compliance, friction, and topography of the surface. Thus, the tactile display can provide information on the surface of an organic tissue to the surgeon in virtual reality. In order to investigate the compliance feeling of a human finger's touch, normal force responses of a tactile display under various magnetic fields have been assessed. Also, shearing friction force responses of the tactile display are investigated to simulate the action of finger dragging on the surface. Moreover, different matrix arrays of magnetic poles are applied to form the virtual surface topography. From the results, different tactile feelings are observed according to the applied magnetic field strength as well as the arrays of magnetic poles combinations. This research presents a smart tactile display technology for virtual surfaces.

Vibrotactile pattern recognition: a portable compact tactile matrix.

PubMed

Thullier, Francine; Bolmont, Benoît; Lestienne, Francis G

2012-02-01

Compact tactile matrix (CTM) is a vibrotactile device composed of a seven-by-seven array of electromechanical vibrators "tactip" used to represent tactile patterns applied to a small skin area. The CTM uses a dynamic feature to generate spatiotemporal tactile patterns. The design requirements focus particularly on maximizing the transmission of the vibration from one tactip to the others as well as to the skin over a square area of 16 cm (2) while simultaneously minimizing the transmission of vibrations throughout the overall structure of the CTM. Experiments were conducted on 22 unpracticed subjects to evaluate how the CTM could be used to develop a tactile semantics for communication of instructions in order to test the ability of the subjects to identify: 1) directional prescriptors for gesture guidance and 2) instructional commands for operational task requirements in a military context. The results indicate that, after familiarization, recognition accuracies in the tactile patterns were remarkably precise for more 80% of the subjects. © 2011 IEEE

Tactile Feedback Display with Spatial and Temporal Resolutions

PubMed Central

Vishniakou, Siarhei; Lewis, Brian W.; Niu, Xiaofan; Kargar, Alireza; Sun, Ke; Kalajian, Michael; Park, Namseok; Yang, Muchuan; Jing, Yi; Brochu, Paul; Sun, Zhelin; Li, Chun; Nguyen, Truong; Pei, Qibing; Wang, Deli

2013-01-01

We report the electronic recording of the touch contact and pressure using an active matrix pressure sensor array made of transparent zinc oxide thin-film transistors and tactile feedback display using an array of diaphragm actuators made of an interpenetrating polymer elastomer network. Digital replay, editing and manipulation of the recorded touch events were demonstrated with both spatial and temporal resolutions. Analog reproduction of the force is also shown possible using the polymer actuators, despite of the high driving voltage. The ability to record, store, edit, and replay touch information adds an additional dimension to digital technologies and extends the capabilities of modern information exchange with the potential to revolutionize physical learning, social networking, e-commerce, robotics, gaming, medical and military applications. PMID:23982053

Tactile feedback display with spatial and temporal resolutions.

PubMed

Vishniakou, Siarhei; Lewis, Brian W; Niu, Xiaofan; Kargar, Alireza; Sun, Ke; Kalajian, Michael; Park, Namseok; Yang, Muchuan; Jing, Yi; Brochu, Paul; Sun, Zhelin; Li, Chun; Nguyen, Truong; Pei, Qibing; Wang, Deli

2013-01-01

We report the electronic recording of the touch contact and pressure using an active matrix pressure sensor array made of transparent zinc oxide thin-film transistors and tactile feedback display using an array of diaphragm actuators made of an interpenetrating polymer elastomer network. Digital replay, editing and manipulation of the recorded touch events were demonstrated with both spatial and temporal resolutions. Analog reproduction of the force is also shown possible using the polymer actuators, despite of the high driving voltage. The ability to record, store, edit, and replay touch information adds an additional dimension to digital technologies and extends the capabilities of modern information exchange with the potential to revolutionize physical learning, social networking, e-commerce, robotics, gaming, medical and military applications.

Tactile Feedback Display with Spatial and Temporal Resolutions

NASA Astrophysics Data System (ADS)

Vishniakou, Siarhei; Lewis, Brian W.; Niu, Xiaofan; Kargar, Alireza; Sun, Ke; Kalajian, Michael; Park, Namseok; Yang, Muchuan; Jing, Yi; Brochu, Paul; Sun, Zhelin; Li, Chun; Nguyen, Truong; Pei, Qibing; Wang, Deli

2013-08-01

We report the electronic recording of the touch contact and pressure using an active matrix pressure sensor array made of transparent zinc oxide thin-film transistors and tactile feedback display using an array of diaphragm actuators made of an interpenetrating polymer elastomer network. Digital replay, editing and manipulation of the recorded touch events were demonstrated with both spatial and temporal resolutions. Analog reproduction of the force is also shown possible using the polymer actuators, despite of the high driving voltage. The ability to record, store, edit, and replay touch information adds an additional dimension to digital technologies and extends the capabilities of modern information exchange with the potential to revolutionize physical learning, social networking, e-commerce, robotics, gaming, medical and military applications.

Aerospace Sensor Systems: From Sensor Development To Vehicle Application

NASA Technical Reports Server (NTRS)

Hunter, Gary W.

2008-01-01

This paper presents an overview of years of sensor system development and application for aerospace systems. The emphasis of this work is on developing advanced capabilities for measurement and control of aeropropulsion and crew vehicle systems as well as monitoring the safety of those systems. Specific areas of work include chemical species sensors, thin film thermocouples and strain gages, heat flux gages, fuel gages, SiC based electronic devices and sensors, space qualified electronics, and MicroElectroMechanical Systems (MEMS) as well as integrated and multifunctional sensor systems. Each sensor type has its own technical challenges related to integration and reliability in a given application. The general approach has been to develop base sensor technology using microfabrication techniques, integrate sensors with "smart" hardware and software, and demonstrate those systems in a range of aerospace applications. Descriptions of the sensor elements, their integration into sensors systems, and examples of sensor system applications will be discussed. Finally, suggestions related to the future of sensor technology will be given. It is concluded that smart micro/nano sensor technology can revolutionize aerospace applications, but significant challenges exist in maturing the technology and demonstrating its value in real-life applications.

Coalition Warfare Program Tactile Situation Awareness System for Aviation Applications: System Development

DTIC Science & Technology

2014-01-01

Advancement, specifically Mr. Ed McDaniel and Mr. Dan Seifert, who managed and pushed forward the Small Business Innovative Research (SBIR) process ...achievements. TSAS is a garment containing vibrotactile stimulators (called tactors) partially covering the torso. The garment provides aircraft flight...awareness. Working in conjunction with two SBIR companies, the recent CWP TSAS effort advanced the state of tactile cueing and delivered TSAS garments

A reconfigurable tactile display based on polymer MEMS technology

NASA Astrophysics Data System (ADS)

Wu, Xiaosong

A tactile display provides information such as shape, texture, temperature, and hardness to a user. Ultimately, a tactile display could be used to recreate a virtual object that may be stored in a computer. However, such advanced displays are not yet widely available, primarily due to the lack of low cost, large area, compact actuator arrays that can stimulate the large numbers of receptors of the user and that can also meet the high requirements for user safety and comfort. This research focuses on the development of polymer microfabrication technologies for the realization of two major components of a pneumatic tactile display: a microactuator array and a complementary microvalve (control) array. In this work, the concept, fabrication, and characterization of a kinematically-stabilized polymeric microbubble actuator ("endoskeletal microbubble actuator") is presented. A systematic design and modeling procedure was carried out to generate an optimized geometry of the corrugated diaphragm to satisfy membrane deflection, force, and stability requirements set forth by the tactile display goals. A mass-manufacturable actuator has been fabricated using the approaches of lithography and micromolding. A prototype of a single endoskeletal bubble actuator with a diameter of 2.6mm has been fabricated and characterized. In addition, in order to further reduce the size and cost of the tactile display, a microvalve array can be integrated into the tactile display system to control the pneumatic fluid that actuates the microbubble actuator. A piezoelectrically-driven and hydraulically-amplified polymer microvalve has been designed, fabricated, and tested. An incompressible elastomer was used as a solid hydraulic medium to convert the small axial displacement of a piezoelectric actuator into a large valve head stroke while maintaining a large blocking force. The function of the microvalve as an on-off switch for a pneumatic microbubble tactile actuator has been demonstrated

Nature as a model for biomimetic sensors

NASA Astrophysics Data System (ADS)

Bleckmann, H.

2012-04-01

Mammals, like humans, rely mainly on acoustic, visual and olfactory information. In addition, most also use tactile and thermal cues for object identification and spatial orientation. Most non-mammalian animals also possess a visual, acoustic and olfactory system. However, besides these systems they have developed a large variety of highly specialized sensors. For instance, pyrophilous insects use infrared organs for the detection of forest fires while boas, pythons and pit vipers sense the infrared radiation emitted by prey animals. All cartilaginous and bony fishes as well as some amphibians have a mechnaosensory lateral line. It is used for the detection of weak water motions and pressure gradients. For object detection and spatial orientation many species of nocturnal fish employ active electrolocation. This review describes certain aspects of the detection and processing of infrared, mechano- and electrosensory information. It will be shown that the study of these seemingly exotic sensory systems can lead to discoveries that are useful for the construction of technical sensors and artificial control systems.

Vibratory tactile display for textures

NASA Technical Reports Server (NTRS)

Ikei, Yasushi; Ikeno, Akihisa; Fukuda, Shuichi

1994-01-01

We have developed a tactile display that produces vibratory stimulus to a fingertip in contact with a vibrating tactor matrix. The display depicts tactile surface textures while the user is exploring a virtual object surface. A piezoelectric actuator drives the individual tactor in accordance with both the finger movement and the surface texture being traced. Spatiotemporal display control schemes were examined for presenting the fundamental surface texture elements. The temporal duration of vibratory stimulus was experimentally optimized to simulate the adaptation process of cutaneous sensation. The selected duration time for presenting a single line edge agreed with the time threshold of tactile sensation. Then spatial stimulus disposition schemes were discussed for representation of other edge shapes. As an alternative means not relying on amplitude control, a method of augmented duration at the edge was investigated. Spatial resolution of the display was measured for the lines presented both in perpendicular and parallel to a finger axis. Discrimination of texture density was also measured on random dot textures.

Role of combined tactile and kinesthetic feedback in minimally invasive surgery.

PubMed

Lim, Soo-Chul; Lee, Hyung-Kew; Park, Joonah

2014-10-18

Haptic feedback is of critical importance in surgical tasks. However, conventional surgical robots do not provide haptic feedback to surgeons during surgery. Thus, in this study, a combined tactile and kinesthetic feedback system was developed to provide haptic feedback to surgeons during robotic surgery. To assess haptic feasibility, the effects of two types of haptic feedback were examined empirically - kinesthetic and tactile feedback - to measure object-pulling force with a telesurgery robotics system at two desired pulling forces (1 N and 2 N). Participants answered a set of questionnaires after experiments. The experimental results reveal reductions in force error (39.1% and 40.9%) when using haptic feedback during 1 N and 2 N pulling tasks. Moreover, survey analyses show the effectiveness of the haptic feedback during teleoperation. The combined tactile and kinesthetic feedback of the master device in robotic surgery improves the surgeon's ability to control the interaction force applied to the tissue. Copyright © 2014 John Wiley & Sons, Ltd. Copyright © 2014 John Wiley & Sons, Ltd.

Setup and evaluation of a sensor tilting system for dimensional micro- and nanometrology

NASA Astrophysics Data System (ADS)

Schuler, Alexander; Weckenmann, Albert; Hausotte, Tino

2014-06-01

Sensors in micro- and nanometrology show their limits if the measurement objects and surfaces feature high aspect ratios, high curvature and steep surface angles. Their measurable surface angle is limited and an excess leads to measurement deviation and not detectable surface points. We demonstrate a principle to adapt the sensor's working angle during the measurement keeping the sensor in its optimal working angle. After the simulation of the principle, a hardware prototype was realized. It is based on a rotary kinematic chain with two rotary degrees of freedom, which extends the measurable surface angle to ±90° and is combined with a nanopositioning and nanomeasuring machine. By applying a calibration procedure with a quasi-tactile 3D sensor based on electrical near-field interaction the systematic position deviation of the kinematic chain is reduced. The paper shows for the first time the completed setup and integration of the prototype, the performance results of the calibration, the measurements with the prototype and the tilting principle, and finishes with the interpretation and feedback of the practical results.

Pre-shaping of the Fingertip of Robot Hand Covered with Net Structure Proximity Sensor

NASA Astrophysics Data System (ADS)

Suzuki, Kenji; Suzuki, Yosuke; Hasegawa, Hiroaki; Ming, Aiguo; Ishikawa, Masatoshi; Shimojo, Makoto

To achieve skillful tasks with multi-fingered robot hands, many researchers have been working on sensor-based control of them. Vision sensors and tactile sensors are indispensable for the tasks, however, the correctness of the information from the vision sensors decreases as a robot hand approaches to a grasping object because of occlusion. This research aims to achieve seamless detection for reliable grasp by use of proximity sensors: correcting the positional error of the hand in vision-based approach, and contacting the fingertip in the posture for effective tactile sensing. In this paper, we propose a method for adjusting the posture of the fingertip to the surface of the object. The method applies “Net-Structure Proximity Sensor” on the fingertip, which can detect the postural error in the roll and pitch axes between the fingertip and the object surface. The experimental result shows that the postural error is corrected in the both axes even if the object dynamically rotates.

A Corticothalamic Circuit for Refining Tactile Encoding.

PubMed

Pauzin, François Philippe; Krieger, Patrik

2018-05-01

A fundamental task for the brain is to determine which aspects of the continuous flow of information is the most relevant in a given behavioral situation. The information flow is regulated via dynamic interactions between feedforward and feedback pathways. One such pathway is via corticothalamic feedback. Layer 6 (L6) corticothalamic (CT) cells make both cortical and thalamic connections and, therefore, are key modulators of activity in both areas. The functional properties of L6 CT cells in sensory processing were investigated in the mouse whisker system. Optogenetic activation of L6 CT neurons decreased spontaneous spiking, with the net effect that a whisker-evoked response was more accurately detected (larger evoked-to-spontaneous spiking ratio) but at the expense of reducing the response probability. In addition, L6 CT activation decreases sensory adaptation in both the thalamus and cortex. L6 CT activity can thus tune the tactile system, depending on the behaviorally relevant tactile input. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Endoscopic vs. tactile evaluation of subgingival calculus.

PubMed

Osborn, Joy B; Lenton, Patricia A; Lunos, Scott A; Blue, Christine M

2014-08-01

Endoscopic technology has been developed to facilitate imagery for use during diagnostic and therapeutic phases of periodontal care. The purpose of this study was to compare the level of subgingival calculus detection using a periodontal endoscope with that of conventional tactile explorer in periodontitis subjects. A convenience sample of 26 subjects with moderate periodontitis in at least 2 quadrants was recruited from the University of Minnesota School of Dentistry to undergo quadrant scaling and root planing. One quadrant from each subject was randomized for tactile calculus detection alone and the other quadrant for tactile detection plus the Perioscope ™ (Perioscopy Inc., Oakland, Cali). A calculus index on a 0 to 3 score was performed at baseline and at 2 post-scaling and root planing visits. Sites where calculus was detected at visit 1 were retreated. T-tests were used to determine within-subject differences between Perioscope™ and tactile measures, and changes in measures between visits. Significantly more calculus was detected using the Perioscope™ vs. tactile explorer for all 3 subject visits (p<0.005). Mean changes (reduction) in calculus detection from baseline to visit 1 were statistically significant for both the Perioscope™ and tactile quadrants (p<0.0001). However, further reductions in calculus detection from visit 1 to visit 2 was only significant for the Perioscope™ quadrant (p<0.025), indicating that this methodology was able to more precisely detect calculus at this visit. It was concluded that the addition of a visual component to calculus detection via the Perioscope™ was most helpful in the re-evaluation phase of periodontal therapy. Copyright © 2014 The American Dental Hygienists’ Association.

Functionalization of Tactile Sensation for Robot Based on Haptograph and Modal Decomposition

NASA Astrophysics Data System (ADS)

Yokokura, Yuki; Katsura, Seiichiro; Ohishi, Kiyoshi

In the real world, robots should be able to recognize the environment in order to be of help to humans. A video camera and a laser range finder are devices that can help robots recognize the environment. However, these devices cannot obtain tactile information from environments. Future human-assisting-robots should have the ability to recognize haptic signals, and a disturbance observer can possibly be used to provide the robot with this ability. In this study, a disturbance observer is employed in a mobile robot to functionalize the tactile sensation. This paper proposes a method that involves the use of haptograph and modal decomposition for the haptic recognition of road environments. The haptograph presents a graphic view of the tactile information. It is possible to classify road conditions intuitively. The robot controller is designed by considering the decoupled modal coordinate system, which consists of translational and rotational modes. Modal decomposition is performed by using a quarry matrix. Once the robot is provided with the ability to recognize tactile sensations, its usefulness to humans will increase.

High Sensitivity Stress Sensor Based on Hybrid Materials

NASA Technical Reports Server (NTRS)

Cao, Xian-An (Inventor)

2014-01-01

A sensing device is used to detect the spatial distributions of stresses applied by physical contact with the surface of the sensor or induced by pressure, temperature gradients, and surface absorption. The sensor comprises a hybrid active layer that includes luminophores doped in a polymeric or organic host, altogether embedded in a matrix. Under an electrical bias, the sensor simultaneously converts stresses into electrical and optical signals. Among many applications, the device may be used for tactile sensing and biometric imaging.

Tactile priming modulates the activation of the fronto-parietal circuit during tactile angle match and non-match processing: an fMRI study

PubMed Central

Yang, Jiajia; Yu, Yinghua; Kunita, Akinori; Huang, Qiang; Wu, Jinglong; Sawamoto, Nobukatsu; Fukuyama, Hidenao

2014-01-01

The repetition of a stimulus task reduces the neural activity within certain cortical regions responsible for working memory (WM) processing. Although previous evidence has shown that repeated vibrotactile stimuli reduce the activation in the ventrolateral prefrontal cortex, whether the repeated tactile spatial stimuli triggered the priming effect correlated with the same cortical region remains unclear. Therefore, we used event-related functional magnetic resonance imaging (fMRI) and a delayed match-to-sample task to investigate the contributions of the priming effect to tactile spatial WM processing. Fourteen healthy volunteers were asked to encode three tactile angle stimuli during the encoding phase and one tactile angle stimulus during the recognition phase. Then, they answered whether the last angle stimulus was presented during the encoding phase. As expected, both the Match and Non-Match tasks activated a similar cerebral network. The critical new finding was decreased brain activity in the left inferior frontal gyrus (IFG), the right posterior parietal cortex (PPC) and bilateral medial frontal gyri (mFG) for the match task compared to the Non-Match task. Therefore, we suggest that the tactile priming engaged repetition suppression mechanisms during tactile angle matching, and this process decreased the activation of the fronto-parietal circuit, including IFG, mFG and PPC. PMID:25566010

Tactile mental body parts representation in obesity.

PubMed

Scarpina, Federica; Castelnuovo, Gianluca; Molinari, Enrico

2014-12-30

Obese people׳s distortions in visually-based mental body-parts representations have been reported in previous studies, but other sensory modalities have largely been neglected. In the present study, we investigated possible differences in tactilely-based body-parts representation between an obese and a healthy-weight group; additionally we explore the possible relationship between the tactile- and the visually-based body representation. Participants were asked to estimate the distance between two tactile stimuli that were simultaneously administered on the arm or on the abdomen, in the absence of visual input. The visually-based body-parts representation was investigated by a visual imagery method in which subjects were instructed to compare the horizontal extension of body part pairs. According to the results, the obese participants overestimated the size of the tactilely-perceived distances more than the healthy-weight group when the arm, and not the abdomen, was stimulated. Moreover, they reported a lower level of accuracy than did the healthy-weight group when estimating horizontal distances relative to their bodies, confirming an inappropriate visually-based mental body representation. Our results imply that body representation disturbance in obese people is not limited to the visual mental domain, but it spreads to the tactilely perceived distances. The inaccuracy was not a generalized tendency but was body-part related. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Recent Advances in Skin-Inspired Sensors Enabled by Nanotechnology

NASA Astrophysics Data System (ADS)

Loh, Kenneth J.; Azhari, Faezeh

2012-07-01

The highly optimized performance of nature's creations and biological assemblies has inspired the development of their bio-inspired artificial counterparts that can potentially outperform conventional systems. In particular, the skin of humans, animals, and insects exhibits unique functionalities and properties and has subsequently led to active research in developing skin-inspired sensors. This paper presents a summary of selected work related to skin-inspired tactile, distributed strain, and artificial hair cell flow sensors, with a particular focus on technologies enabled by recent advancements in the nanotechnology domain. The purpose is not to present a comprehensive review on this broad subject matter but rather to use selected work to outline the diversity of current research activities.

A novel airway device with tactile sensing capabilities for verifying correct endotracheal tube placement.

PubMed

Goethals, Pauwel; Chaobal, Harshu; Reynaerts, Dominiek; Schaner, David

2014-04-01

We present a new device for verifying endotracheal tube (ETT) position that uses specialized sensors intended to distinguish anatomical features of the trachea and esophagus. This device has the potential to increase the safety of resuscitation, surgery, and mechanical ventilation and decrease the morbidity, mortality, and health care costs associated with esophageal intubation and unintended extubation by potentially improving the process and maintenance of endotracheal intubation. The device consists of a tactile sensor connected to the airway occlusion cuff of an ETT. It is intended to detect the presence or absence of tracheal rings immediately upon inflation of the airway occlusion cuff. The initial study detailed here verifies that a prototype device can detect contours similar to tracheal rings in a tracheal model.

Tactile roughness perception in the presence of olfactory and trigeminal stimulants

PubMed Central

Koijck, Lara A.; Van Erp, Jan B.F.

2015-01-01

Previous research has shown that odorants consistently evoke associations with textures and their tactile properties like smoothness and roughness. Also, it has been observed that olfaction can modulate tactile perception. We therefore hypothesized that tactile roughness perception may be biased towards the somatosensory connotation of an ambient odorant. We performed two experiments to test this hypothesis. In the first experiment, we investigated the influence of ambient chemosensory stimuli with different roughness connotations on tactile roughness perception. In addition to a pleasant odor with a connotation of softness (PEA), we also included a trigeminal stimulant with a rough, sharp or prickly connotation (Ethanol). We expected that—compared to a No-odorant control condition—tactile texture perception would be biased towards smoothness in the presence of PEA and towards roughness in the presence of Ethanol. However, our results show no significant interaction between chemosensory stimulation and perceived tactile surface roughness. It could be argued that ambient odors may be less effective in stimulating crossmodal associations, since they are by definition extraneous to the tactile stimuli. In an attempt to optimize the conditions for sensory integration, we therefore performed a second experiment in which the olfactory and tactile stimuli were presented in synchrony and in close spatial proximity. In addition, we included pleasant (Lemon) and unpleasant (Indole) odorants that are known to have the ability to affect tactile perception. We expected that tactile stimuli would be perceived as less rough when simultaneously presented with Lemon or PEA (both associated with softness) than when presented with Ethanol or Indole (odors that can be associated with roughness). Again, we found no significant main effect of chemosensory condition on perceived tactile roughness. We discuss the limitations of this study and we present suggestions for future research

Method and device for producing a tactile display using an electrorheological fluid

NASA Technical Reports Server (NTRS)

Garner, H. Douglas (Inventor)

1996-01-01

A tactile display device utilizes an electrorheological fluid to activate a plurality of tactile dots. A voltage is selectively produced uniformly across an electrorheological fluid flowing between a common ground electrode and a plurality of conductive dot electrodes, thereby producing an increase in the fluid's viscosity to the extent that fluid flow between the two electrodes is restricted. The flow restriction produces a build-up of electrorheological fluid in a corresponding dot actuator chamber. The resulting pressure increase in the chamber displaces an elastic diaphragm fixed to a display surface to form a lump which can be perceived by the reader as one dot in a Braille character cell. A flow regulation system provides a continually pressurized flow system and provides for free flow of the electrorheological fluid through the plurality of dot actuator chambers when they are not activated. The device is adaptable to printed circuit techniques and can simultaneously display tactile dots representative of a full page of Braille characters stored on a medium such as a tape cassette or to display tactile dots representative of non-Braille data appearing on a computer monitor or contained on another data storage medium. In an alternate embodiment, the elastic diaphragm drives a plurality of spring-loaded pins provided with positive stops to maintain consistent displacements of the pins in both their actuated and nonactuated positions.

Unmyelinated tactile cutaneous nerves signal erotic sensations.

PubMed

Jönsson, Emma H; Backlund Wasling, Helena; Wagnbeck, Vicktoria; Dimitriadis, Menelaos; Georgiadis, Janniko R; Olausson, Håkan; Croy, Ilona

2015-06-01

Intrapersonal touch is a powerful tool for communicating emotions and can among many things evoke feelings of eroticism and sexual arousal. The peripheral neural mechanisms of erotic touch signaling have been less studied. C tactile afferents (unmyelinated low-threshold mechanoreceptors), known to underpin pleasant aspects of touch processing, have been posited to play an important role. In two studies, we investigated the relationship between C tactile activation and the perception of erotic and pleasant touch, using tactile brushing stimulation. In total, 66 healthy subjects (37 women, age range 19-51 years) were examined. In study 1 (n = 20), five different stroking velocities were applied to the forearm and the inner thigh. The participants answered questions about partnership, mood, and touch. In study 2 (n = 46), the same five stroking velocities were applied to the forearm. The participants answered questions about partnership, touch, and sexuality. Both touch eroticism and pleasantness were rated significantly higher for C tactile optimal velocities compared with suboptimal velocities. No difference was found between the ratings of the thigh and the forearm. The velocity-dependent rating curves of pleasantness, intensity, and eroticism differed from each other. Pleasantness was best explained by a quadratic fit, intensity by a linear fit, and eroticism by both. A linear transformation of pleasantness and intensity predicted the observed eroticism ratings reliably. Eroticism ratings were negatively correlated with length of relationship. Touch was rated most erotic when perceived as pleasant and weak. In human hairy skin, perception of pleasantness is correlated with the firing rate of C tactile afferents, and perception of intensity is correlated with the firing rate of Aβ afferents. Accordingly, eroticism may be perceived most readily for touch stimuli that induce high activity in C tactile fibers and low activity in Aβ fibers. © 2015 International

Fiber optic sensors; Proceedings of the Meeting, Cannes, France, November 26, 27, 1985

NASA Technical Reports Server (NTRS)

Arditty, Herve J. (Editor); Jeunhomme, Luc B. (Editor)

1986-01-01

The conference presents papers on distributed sensors and sensor networks, signal processing and detection techniques, temperature measurements, chemical sensors, and the measurement of pressure, strain, and displacements. Particular attention is given to optical fiber distributed sensors and sensor networks, tactile sensing in robotics using an optical network and Z-plane techniques, and a spontaneous Raman temperature sensor. Other topics include coherence in optical fiber gyroscopes, a high bandwidth two-phase flow void fraction fiber optic sensor, and a fiber-optic dark-field microbend sensor.

Vibration-enhanced posture stabilization achieved by tactile supplementation: may blind individuals get extra benefits?

PubMed

Magalhães, Fernando Henrique; Kohn, André Fabio

2011-08-01

Diminished balance ability poses a serious health risk due to the increased likelihood of falling, and impaired postural stability is significantly associated with blindness and poor vision. Noise stimulation (by improving the detection of sub-threshold somatosensory information) and tactile supplementation (i.e., additional haptic information provided by an external contact surface) have been shown to improve the performance of the postural control system. Moreover, vibratory noise added to the source of tactile supplementation (e.g., applied to a surface that the fingertip touches) has been shown to enhance balance stability more effectively than tactile supplementation alone. In view of the above findings, in addition to the well established consensus that blind subjects show superior abilities in the use of tactile information, we hypothesized that blind subjects may take extra benefits from the vibratory noise added to the tactile supplementation and hence show greater improvements in postural stability than those observed for sighted subjects. If confirmed, this hypothesis may lay the foundation for the development of noise-based assistive devices (e.g., canes, walking sticks) for improving somatosensation and hence prevent falls in blind individuals. Copyright © 2011 Elsevier Ltd. All rights reserved.

MEMS tactile display: from fabrication to characterization

NASA Astrophysics Data System (ADS)

Miki, Norihisa; Kosemura, Yumi; Watanabe, Junpei; Ishikawa, Hiroaki

2014-03-01

We report fabrication and characterization of MEMS-based tactile display that can display users various tactile information, such as Braille codes and surface textures. The display consists of 9 micro-actuators that are equipped with hydraulic displacement amplification mechanism (HDAM) to achieve large enough displacement to stimulate the human tactile receptors. HDAM encapsulates incompressible liquids. We developed a liquid encapsulation process, which we termed as Bonding-in-Liquid Technique, where bonding with a UV-curable resin in glycerin is conducted in the liquid, which prevented interfusion of air bubbles and deformation of the membrane during the bonding. HDAM successfully amplified the displacement generated by piezoelectric actuators by a factor of 6. The display could virtually produce "rough" and "smooth" surfaces, by controlling the vibration frequency, displacement, and the actuation periods of an actuator until the adjacent actuator was driven. We introduced a sample comparison method to characterize the surfaces, which involves human tactile sensation. First, we prepared samples whose mechanical properties are known. We displayed a surface texture to the user by controlling the parameters and then, the user selects a sample that has the most similar surface texture. By doing so, we can correlate the parameters with the mechanical properties of the sample as well as find the sets of the parameters that can provide similar tactile information to many users. The preliminary results with respect to roughness and hardness is presented.

A nano-microstructured artificial-hair-cell-type sensor based on topologically graded 3D carbon nanotube bundles

NASA Astrophysics Data System (ADS)

Yilmazoglu, O.; Yadav, S.; Cicek, D.; Schneider, J. J.

2016-09-01

A design for a unique artificial-hair-cell-type sensor (AHCTS) based entirely on 3D-structured, vertically aligned carbon nanotube (CNT) bundles is introduced. Standard microfabrication techniques were used for the straightforward micro-nano integration of vertically aligned carbon nanotube arrays composed of low-layer multi-walled CNTs (two to six layers). The mechanical properties of the carbon nanotube bundles were intensively characterized with regard to various substrates and CNT morphology, e.g. bundle height. The CNT bundles display excellent flexibility and mechanical stability for lateral bending, showing high tear resistance. The integrated 3D CNT sensor can detect three-dimensional forces using the deflection or compression of a central CNT bundle which changes the contact resistance to the shorter neighboring bundles. The complete sensor system can be fabricated using a single chemical vapor deposition (CVD) process step. Moreover, sophisticated external contacts to the surroundings are not necessary for signal detection. No additional sensors or external bias for signal detection are required. This simplifies the miniaturization and the integration of these nanostructures for future microsystem set-ups. The new nanostructured sensor system exhibits an average sensitivity of 2100 ppm in the linear regime with the relative resistance change per micron (ppm μm-1) of the individual CNT bundle tip deflection. Furthermore, experiments have shown highly sensitive piezoresistive behavior with an electrical resistance decrease of up to ˜11% at 50 μm mechanical deflection. The detection sensitivity is as low as 1 μm of deflection, and thus highly comparable with the tactile hair sensors of insects, having typical thresholds on the order of 30-50 μm. The AHCTS can easily be adapted and applied as a flow, tactile or acceleration sensor as well as a vibration sensor. Potential applications of the latter might come up in artificial cochlear systems. In

A tactile paging system for deaf-blind people, phase 1. [human factors engineering of bioinstrumentation

NASA Technical Reports Server (NTRS)

Baer, J. A.

1976-01-01

A tactile paging system for deaf-blind people has been brought from the concept stage to the development of a first model. The model consists of a central station that transmits coded information via radio link to an on-body (i.e., worn on the wrist) receiving unit, the output from which is a coded vibrotactile signal. The model is a combination of commercially available equipment, customized electronic circuits, and electromechanical transducers. The paging system facilitates communication to deaf-blind clients in an institutional environment as an aid in their training and other activities. Several subunits of the system were individually developed, tested, and integrated into an operating system ready for experimentation and evaluation. The operation and characteristics of the system are described and photographs are shown.

Tactile texture and friction of soft sponge surfaces.

PubMed

Takahashi, Akira; Suzuki, Makoto; Imai, Yumi; Nonomura, Yoshimune

2015-06-01

We evaluated the tactile texture and frictional properties of five soft sponges with various cell sizes. The frictional forces were measured by a friction meter containing a contact probe with human-finger-like geometry and mechanical properties. When the subjects touched these sponges with their fingers, hard-textured sponges were deemed unpleasant. This tactile feeling changed with friction factors including friction coefficients, their temporal patterns, as well as mechanical and shape factors. These findings provide useful information on how to control the tactile textures of various sponges. Copyright © 2015 Elsevier B.V. All rights reserved.

Differential effects of tactile high- and low-frequency stimulation on tactile discrimination in human subjects.

PubMed

Ragert, Patrick; Kalisch, Tobias; Bliem, Barbara; Franzkowiak, Stephanie; Dinse, Hubert R

2008-01-23

Long-term potentiation (LTP) and long-term depression (LTD) play important roles in mediating activity-dependent changes in synaptic transmission and are believed to be crucial mechanisms underlying learning and cortical plasticity. In human subjects, however, the lack of adequate input stimuli for the induction of LTP and LTD makes it difficult to study directly the impact of such protocols on behavior. Using tactile high- and low-frequency stimulation protocols in humans, we explored the potential of such protocols for the induction of perceptual changes. We delivered tactile high-frequency and low-frequency stimuli (t-HFS, t-LFS) to skin sites of approximately 50 mm2 on the tip of the index finger. As assessed by 2-point discrimination, we demonstrate that 20 minutes of t-HFS improved tactile discrimination, while t-LFS impaired performance. T-HFS-effects were stable for at least 24 hours whereas t-LFS-induced changes recovered faster. While t-HFS changes were spatially very specific with no changes on the neighboring fingers, impaired tactile performance after t-LFS was also observed on the right middle-finger. A central finding was that for both t-LFS and t-HFS perceptual changes were dependent on the size of the stimulated skin area. No changes were observed when the stimulated area was very small (< 1 mm2) indicating special requirements for spatial summation. Our results demonstrate differential effects of such protocols in a frequency specific manner that might be related to LTP- and LTD-like changes in human subjects.

Efficacy of Directional Cues from a Tactile System for Target Orientation in Helicopter Extractions over Moving Targets

DTIC Science & Technology

2013-01-01

incapacitating simulator sickness, current use of medications that alter sleep/ wake cycles, current acute illness, and significant sleep deprivation...tactile cueing using pager motors were not successful in the aviation environment due to ambient noise and vibration obscuring the tactile stimulus (see...continuous wakefulness ). Each day, each participant performed four, 10-minute stabilized hovering A B 6 maneuvers (at 70 feet above ground level

Teaching young people who are blind and have autism to make requests using a variation on the picture exchange communication system with tactile symbols: a preliminary investigation.

PubMed

Lund, Shelley K; Troha, Jeanette M

2008-04-01

This study used a single-subject multiple baseline across participants design to evaluate the effectiveness of a modified picture exchange communication system (PECS) teaching protocol with tactile symbols. Three students (two male, one female) aged 12-17 years who had autism and were blind participated in the study. The instructional program involved three phases. First, each participant learned to exchange a tactile symbol with his/her communication partner to request a preferred item/activity. Second, the distance between the communication partner and the participant was increased. Third, the participants were required to discriminate between two dissimilar tactile symbols. One out of three participants completed all phases of the instructional program. Although the other two participants did not complete the program, they demonstrated improvement from baseline responding rates. This study provided preliminary results that using tactile symbols with strategies from PECS may be an effective method to teach requesting to youth who are blind and have autism.

Hair sensor using a photoelectronic principle for sensing airflow and its direction

NASA Astrophysics Data System (ADS)

Huang, Kuang-Yuh; Huang, Chien-Tai

2011-01-01

Many organisms have diverse hair cells to instantaneously perceive the change of surroundings so that they can keep away from threats. These organs can precisely detect the tiny variations of airflow, water flow, sound, or pressure, and also resolve their affecting directions. Through this brilliant inspiration by the insects' cilia, we decided to design and develop a hair sensor for detecting two-dimensional airflow and pressure waves by using photoelectronic principles. The hair sensor inherently consists of an artificial cilium supported by an elastic membrane. A light-emitting diode and a quadrant photodiode are used as the photoelectronic sensor. The airflow or pressure wave directly stimulates the cilium to sway, and this motion contributes to let the projected light beam shift over the quadrant photodiode, whose four photodiodes produce then corresponding output signals. Because of dynamic and high-sensitive properties of the photoelectronic sensor, the hair sensor we developed possesses a high measurement resolution to be able to detect very tiny stimulation and its affecting direction. According to its multifaceted characteristics and simple structure, the hair sensor can be applied in numerous potential application fields, such as intrusion alarm system, noise detection system, as well as a tactile sensor.

Tactile Radar: experimenting a computer game with visually disabled.

PubMed

Kastrup, Virgínia; Cassinelli, Alvaro; Quérette, Paulo; Bergstrom, Niklas; Sampaio, Eliana

2017-09-18

Visually disabled people increasingly use computers in everyday life, thanks to novel assistive technologies better tailored to their cognitive functioning. Like sighted people, many are interested in computer games - videogames and audio-games. Tactile-games are beginning to emerge. The Tactile Radar is a device through which a visually disabled person is able to detect distal obstacles. In this study, it is connected to a computer running a tactile-game. The game consists in finding and collecting randomly arranged coins in a virtual room. The study was conducted with nine congenital blind people including both sexes, aged 20-64 years old. Complementary methods of first and third person were used: the debriefing interview and the quasi-experimental design. The results indicate that the Tactile Radar is suitable for the creation of computer games specifically tailored for visually disabled people. Furthermore, the device seems capable of eliciting a powerful immersive experience. Methodologically speaking, this research contributes to the consolidation and development of first and third person complementary methods, particularly useful in disabled people research field, including the evaluation by users of the Tactile Radar effectiveness in a virtual reality context. Implications for rehabilitation Despite the growing interest in virtual games for visually disabled people, they still find barriers to access such games. Through the development of assistive technologies such as the Tactile Radar, applied in virtual games, we can create new opportunities for leisure, socialization and education for visually disabled people. The results of our study indicate that the Tactile Radar is adapted to the creation of video games for visually disabled people, providing a playful interaction with the players.

A platform-based foot pressure/shear sensor

NASA Astrophysics Data System (ADS)

Chang, Chun-Te; Liu, Chao Shih; Soetanto, William; Wang, Wei-Chih

2012-04-01

The proposed research is aimed at developing, fabricating and implementing a flexible fiber optic bend loss sensor for the measurement of plantar pressure and shear stress for diabetic patients. The successful development of the sensor will greatly impact the study of diabetic foot ulcers by allowing clinicians to measure a parameter (namely, shear stress) that has been implicated in ulceration, but heretofore, has not been routinely quantified on high risk patients. A full-scale foot pressure/shear sensor involves a tactile sensor array using intersecting optical waveguides is presented. The basic configuration of the optical sensor systems incorporates a mesh that is comprised of two sets of parallel optical waveguide planes; the planes are configured so the parallel rows of waveguides of the top and bottom planes are perpendicular to each other. The planes are sandwiched together creating one sensing sheet. Two-dimensional information is determined by measuring the loss of light from each of the waveguide to map the overall pressure distribution. The shifting of the layers relative to each other allows determination of the shear stress in the plane of the sensor. This paper presents latest development and improvement in the sensors design. Fabrication and results from the latest tests will be described.

Graphical tactile displays for visually-impaired people.

PubMed

Vidal-Verdú, Fernando; Hafez, Moustapha

2007-03-01

This paper presents an up-to-date survey of graphical tactile displays. These devices provide information through the sense of touch. At best, they should display both text and graphics (text may be considered a type of graphic). Graphs made with shapeable sheets result in bulky items awkward to store and transport; their production is expensive and time-consuming and they deteriorate quickly. Research is ongoing for a refreshable tactile display that acts as an output device for a computer or other information source and can present the information in text and graphics. The work in this field has branched into diverse areas, from physiological studies to technological aspects and challenges. Moreover, interest in these devices is now being shown by other fields such as virtual reality, minimally invasive surgery and teleoperation. It is attracting more and more people, research and money. Many proposals have been put forward, several of them succeeding in the task of presenting tactile information. However, most are research prototypes and very expensive to produce commercially. Thus the goal of an efficient low-cost tactile display for visually-impaired people has not yet been reached.

RETENTION OF HIGH TACTILE ACUITY THROUGHOUT THE LIFESPAN IN BLINDNESS

PubMed Central

Legge, Gordon E.; Madison, Cindee; Vaughn, Brenna N.; Cheong, Allen M.Y.; Miller, Joseph C.

2009-01-01

Previous studies of tactile acuity on the fingertip using passive touch have demonstrated an age-related decline in spatial resolution for both sighted and blind subjects. We have re-examined this age dependence with two newly designed tactile-acuity charts requiring active exploration of the test symbols. One chart used dot patterns similar to Braille and the other used embossed Landolt rings. Groups of blind Braille readers and sighted subjects, ranging in age from 12 to 85 years, were tested in two experiments. We replicated previous findings for sighted subjects by showing an age related decrease in tactile acuity by nearly 1% per year. Surprisingly, the blind subjects retained high acuity into old age showing no age-related decline. For the blind subjects, tactile acuity did not correlate with braille reading speed, the amount of daily reading, or the age at which braille was learned. We conclude that when measured with active touch, blind subjects retain high tactile acuity into old age, unlike their aging sighted peers. We propose that blind people's use of active touch in daily activities, not specifically Braille reading, results in preservation of tactile acuity across the lifespan. PMID:19064491

To what extent do Gestalt grouping principles influence tactile perception?

PubMed

Gallace, Alberto; Spence, Charles

2011-07-01

Since their formulation by the Gestalt movement more than a century ago, the principles of perceptual grouping have primarily been investigated in the visual modality and, to a lesser extent, in the auditory modality. The present review addresses the question of whether the same grouping principles also affect the perception of tactile stimuli. Although, to date, only a few studies have explicitly investigated the existence of Gestalt grouping principles in the tactile modality, we argue that many more studies have indirectly provided evidence relevant to this topic. Reviewing this body of research, we argue that similar principles to those reported previously in visual and auditory studies also govern the perceptual grouping of tactile stimuli. In particular, we highlight evidence showing that the principles of proximity, similarity, common fate, good continuation, and closure affect tactile perception in both unimodal and crossmodal settings. We also highlight that the grouping of tactile stimuli is often affected by visual and auditory information that happen to be presented simultaneously. Finally, we discuss the theoretical and applied benefits that might pertain to the further study of Gestalt principles operating in both unisensory and multisensory tactile perception.

Blindness enhances tactile acuity and haptic 3-D shape discrimination.

PubMed

Norman, J Farley; Bartholomew, Ashley N

2011-10-01

This study compared the sensory and perceptual abilities of the blind and sighted. The 32 participants were required to perform two tasks: tactile grating orientation discrimination (to determine tactile acuity) and haptic three-dimensional (3-D) shape discrimination. The results indicated that the blind outperformed their sighted counterparts (individually matched for both age and sex) on both tactile tasks. The improvements in tactile acuity that accompanied blindness occurred for all blind groups (congenital, early, and late). However, the improvements in haptic 3-D shape discrimination only occurred for the early-onset and late-onset blindness groups; the performance of the congenitally blind was no better than that of the sighted controls. The results of the present study demonstrate that blindness does lead to an enhancement of tactile abilities, but they also suggest that early visual experience may play a role in facilitating haptic 3-D shape discrimination.

Perception-based 3D tactile rendering from a single image for human skin examinations by dynamic touch.

PubMed

Kim, K; Lee, S

2015-05-01

Diagnosis of skin conditions is dependent on the assessment of skin surface properties that are represented by more tactile properties such as stiffness, roughness, and friction than visual information. Due to this reason, adding tactile feedback to existing vision based diagnosis systems can help dermatologists diagnose skin diseases or disorders more accurately. The goal of our research was therefore to develop a tactile rendering system for skin examinations by dynamic touch. Our development consists of two stages: converting a single image to a 3D haptic surface and rendering the generated haptic surface in real-time. Converting to 3D surfaces from 2D single images was implemented with concerning human perception data collected by a psychophysical experiment that measured human visual and haptic sensibility to 3D skin surface changes. For the second stage, we utilized real skin biomechanical properties found by prior studies. Our tactile rendering system is a standalone system that can be used with any single cameras and haptic feedback devices. We evaluated the performance of our system by conducting an identification experiment with three different skin images with five subjects. The participants had to identify one of the three skin surfaces by using a haptic device (Falcon) only. No visual cue was provided for the experiment. The results indicate that our system provides sufficient performance to render discernable tactile rendering with different skin surfaces. Our system uses only a single skin image and automatically generates a 3D haptic surface based on human haptic perception. Realistic skin interactions can be provided in real-time for the purpose of skin diagnosis, simulations, or training. Our system can also be used for other applications like virtual reality and cosmetic applications. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Fingerprint-Inspired Flexible Tactile Sensor for Accurately Discerning Surface Texture.

PubMed

Cao, Yudong; Li, Tie; Gu, Yang; Luo, Hui; Wang, Shuqi; Zhang, Ting

2018-04-01

Inspired by the epidermal-dermal and outer microstructures of the human fingerprint, a novel flexible sensor device is designed to improve haptic perception and surface texture recognition, which is consisted of single-walled carbon nanotubes, polyethylene, and polydimethylsiloxane with interlocked and outer micropyramid arrays. The sensor shows high pressure sensitivity (-3.26 kPa -1 in the pressure range of 0-300 Pa), and it can detect the shear force changes induced by the dynamic interaction between the outer micropyramid structure on the sensor and the tested material surface, and the minimum dimension of the microstripe that can be discerned is as low as 15 µm × 15 µm (interval × width). To demonstrate the texture discrimination capability, the sensors are tested for accurately discerning various surface textures, such as the textures of different fabrics, Braille characters, the inverted pyramid patterns, which will have great potential in robot skins and haptic perception, etc. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Visual and tactile interfaces for bi-directional human robot communication

NASA Astrophysics Data System (ADS)

Barber, Daniel; Lackey, Stephanie; Reinerman-Jones, Lauren; Hudson, Irwin

2013-05-01

Seamless integration of unmanned and systems and Soldiers in the operational environment requires robust communication capabilities. Multi-Modal Communication (MMC) facilitates achieving this goal due to redundancy and levels of communication superior to single mode interaction using auditory, visual, and tactile modalities. Visual signaling using arm and hand gestures is a natural method of communication between people. Visual signals standardized within the U.S. Army Field Manual and in use by Soldiers provide a foundation for developing gestures for human to robot communication. Emerging technologies using Inertial Measurement Units (IMU) enable classification of arm and hand gestures for communication with a robot without the requirement of line-of-sight needed by computer vision techniques. These devices improve the robustness of interpreting gestures in noisy environments and are capable of classifying signals relevant to operational tasks. Closing the communication loop between Soldiers and robots necessitates them having the ability to return equivalent messages. Existing visual signals from robots to humans typically require highly anthropomorphic features not present on military vehicles. Tactile displays tap into an unused modality for robot to human communication. Typically used for hands-free navigation and cueing, existing tactile display technologies are used to deliver equivalent visual signals from the U.S. Army Field Manual. This paper describes ongoing research to collaboratively develop tactile communication methods with Soldiers, measure classification accuracy of visual signal interfaces, and provides an integration example including two robotic platforms.

Displacement sensors using soft magnetostrictive alloys

NASA Astrophysics Data System (ADS)

Hristoforou, E.; Reilly, R. E.

1994-09-01

We report results on the response of a family of displacement sensors, which are based on the magentostrictive delay line (MDL) technique, using current conductors orthogonal to the MDL. Such sensing technique is based on the change of the magnetic circuit at the acoustic stress point of origin due to the displacement of a soft magnetic material above it. Integrated arrays of sensors can be obtained due to the acoustic delay line technique and they can be used as tactile arrays, digitizers or devices for medical applications (gait analysis etc.), while absence of hysteresis and low cost of manufacturing make them competent in this sector of sensor market.

Integrated arrays of air-dielectric graphene transistors as transparent active-matrix pressure sensors for wide pressure ranges.

PubMed

Shin, Sung-Ho; Ji, Sangyoon; Choi, Seiho; Pyo, Kyoung-Hee; Wan An, Byeong; Park, Jihun; Kim, Joohee; Kim, Ju-Young; Lee, Ki-Suk; Kwon, Soon-Yong; Heo, Jaeyeong; Park, Byong-Guk; Park, Jang-Ung

2017-03-31

Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such as electronic skins and health-monitoring devices. Although existing pressure sensors display high sensitivities, they can only be used for specific purposes due to the narrow range of detectable pressure (under tens of kPa) and the difficulty of forming highly integrated arrays. However, it is essential to develop tactile pressure sensors with a wide pressure range in order to use them for diverse application areas including medical diagnosis, robotics or automotive electronics. Here we report an unconventional approach for fabricating fully integrated active-matrix arrays of pressure-sensitive graphene transistors with air-dielectric layers simply formed by folding two opposing panels. Furthermore, this realizes a wide tactile pressure sensing range from 250 Pa to ∼3 MPa. Additionally, fabrication of pressure sensor arrays and transparent pressure sensors are demonstrated, suggesting their substantial promise as next-generation electronics.

Integrated arrays of air-dielectric graphene transistors as transparent active-matrix pressure sensors for wide pressure ranges

NASA Astrophysics Data System (ADS)

Shin, Sung-Ho; Ji, Sangyoon; Choi, Seiho; Pyo, Kyoung-Hee; Wan An, Byeong; Park, Jihun; Kim, Joohee; Kim, Ju-Young; Lee, Ki-Suk; Kwon, Soon-Yong; Heo, Jaeyeong; Park, Byong-Guk; Park, Jang-Ung

2017-03-01

Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such as electronic skins and health-monitoring devices. Although existing pressure sensors display high sensitivities, they can only be used for specific purposes due to the narrow range of detectable pressure (under tens of kPa) and the difficulty of forming highly integrated arrays. However, it is essential to develop tactile pressure sensors with a wide pressure range in order to use them for diverse application areas including medical diagnosis, robotics or automotive electronics. Here we report an unconventional approach for fabricating fully integrated active-matrix arrays of pressure-sensitive graphene transistors with air-dielectric layers simply formed by folding two opposing panels. Furthermore, this realizes a wide tactile pressure sensing range from 250 Pa to ~3 MPa. Additionally, fabrication of pressure sensor arrays and transparent pressure sensors are demonstrated, suggesting their substantial promise as next-generation electronics.

Integrated arrays of air-dielectric graphene transistors as transparent active-matrix pressure sensors for wide pressure ranges

PubMed Central

Shin, Sung-Ho; Ji, Sangyoon; Choi, Seiho; Pyo, Kyoung-Hee; Wan An, Byeong; Park, Jihun; Kim, Joohee; Kim, Ju-Young; Lee, Ki-Suk; Kwon, Soon-Yong; Heo, Jaeyeong; Park, Byong-Guk; Park, Jang-Ung

2017-01-01

Integrated electronic circuitries with pressure sensors have been extensively researched as a key component for emerging electronics applications such as electronic skins and health-monitoring devices. Although existing pressure sensors display high sensitivities, they can only be used for specific purposes due to the narrow range of detectable pressure (under tens of kPa) and the difficulty of forming highly integrated arrays. However, it is essential to develop tactile pressure sensors with a wide pressure range in order to use them for diverse application areas including medical diagnosis, robotics or automotive electronics. Here we report an unconventional approach for fabricating fully integrated active-matrix arrays of pressure-sensitive graphene transistors with air-dielectric layers simply formed by folding two opposing panels. Furthermore, this realizes a wide tactile pressure sensing range from 250 Pa to ∼3 MPa. Additionally, fabrication of pressure sensor arrays and transparent pressure sensors are demonstrated, suggesting their substantial promise as next-generation electronics. PMID:28361867

Noncontact Tactile Display Based on Radiation Pressure of Airborne Ultrasound.

PubMed

Hoshi, T; Takahashi, M; Iwamoto, T; Shinoda, H

2010-01-01

This paper describes a tactile display which provides unrestricted tactile feedback in air without any mechanical contact. It controls ultrasound and produces a stress field in a 3D space. The principle is based on a nonlinear phenomenon of ultrasound: Acoustic radiation pressure. The fabricated prototype consists of 324 airborne ultrasound transducers, and the phase and intensity of each transducer are controlled individually to generate a focal point. The DC output force at the focal point is 16 mN and the diameter of the focal point is 20 mm. The prototype produces vibrations up to 1 kHz. An interaction system including the prototype is also introduced, which enables users to see and touch virtual objects.

Laser sensor system documentation.

DOT National Transportation Integrated Search

2017-03-01

Phase 1 of TxDOT Project 0-6873, True Road Surface Deflection Measuring Device, developed a : laser sensor system based on several sensors mounted on a rigid beam. : This sensor system remains with CTR currently, as the project is moving into Phase 2...

The Effects of Extravehicular Activity (EVA) Glove Pressure on Tactility

NASA Technical Reports Server (NTRS)

Thompson, Shelby; Miranda, Mesloh; England, Scott; Benson, Elizabeth; Rajulu, Sudhakar

2010-01-01

The purpose of the current study was to quantify finger tactility, while wearing a Phase VI Extravehicular Activity (EVA) glove. Subjects were fully suited in an Extravehicular Mobility Unit (EMU) suit. Data was collected under three conditions: bare-handed, gloved at 0 psi, and gloved at 4.3 psi. In order to test tactility, a series of 30 tactile stimuli (bumps) were created that varied in both height and width. With the hand obscured, subjects applied pressure to each bump until detected tactilely. The amount of force needed to detect each bump was recorded using load cells located under a force-plate. The amount of force needed to detect a bump was positively related to width, but inversely related to height. In addition, as the psi of the glove increased, more force was needed to detect the bump. In terms of application, it was possible to determine the optimal width and height a bump needs to be for a specific amount of force applied for tactility.

Tactile Sensors for Palm-Size Crawling Robots

DTIC Science & Technology

2014-05-01

lamination and laser cutting . For the sensor array discussed in this report, the hairs have an average normal sensitivity of approximately 0.8 grams/hair, but...Adhesive (M) Hair Mounting Layer. For visualization purposes, layers I and M are shown with laser - cut features that are actually formed after...The levers are then partially freed from the structure via laser - cutting . The levers are left partly connected at this point so that the hairs (L) can

Touch Sensor Responds to Contact Pressure

NASA Technical Reports Server (NTRS)

Bejczy, A. K.

1982-01-01

Optical tactile sensor for mechanical hands senses contact pressure via change in light reflected from an elastic covering. Pressure against a cell cover causes distortion, which changes internal reflection of light. Change is sensed by detector, and output signal informs operator of contact. The greater the pressure and distortion, the greater the change in light reflection.

Vertically aligned multiwalled carbon nanotubes for pressure, tactile and vibration sensing.

PubMed

Yilmazoglu, O; Popp, A; Pavlidis, D; Schneider, J J; Garth, D; Schüttler, F; Battenberg, G

2012-03-02

We report a simple method for the micro-nano integration of flexible, vertically aligned multiwalled CNT arrays sandwiched between a top and bottom carbon layer via a porous alumina (Al(2)O(3)) template approach. The electromechanical properties of the flexible CNT arrays have been investigated under mechanical stress conditions. First experiments show highly sensitive piezoresistive sensors with a resistance decrease of up to ∼35% and a spatial resolution of <1 mm. The results indicate that these CNT structures can be utilized for tactile sensing components. They also confirm the feasibility of accessing and utilizing nanoscopic CNT bundles via lithographic processing. The method involves room-temperature processing steps and standard microfabrication techniques.

Contextual cueing of tactile search is coded in an anatomical reference frame.

PubMed

Assumpção, Leonardo; Shi, Zhuanghua; Zang, Xuelian; Müller, Hermann J; Geyer, Thomas

2018-04-01

This work investigates the reference frame(s) underlying tactile context memory, a form of statistical learning in a tactile (finger) search task. In this task, if a searched-for target object is repeatedly encountered within a stable spatial arrangement of task-irrelevant distractors, detecting the target becomes more efficient over time (relative to nonrepeated arrangements), as learned target-distractor spatial associations come to guide tactile search, thus cueing attention to the target location. Since tactile search displays can be represented in several reference frames, including multiple external and an anatomical frame, in Experiment 1 we asked whether repeated search displays are represented in tactile memory with reference to an environment-centered or anatomical reference frame. In Experiment 2, we went on examining a hand-centered versus anatomical reference frame of tactile context memory. Observers performed a tactile search task, divided into a learning and test session. At the transition between the two sessions, we introduced postural manipulations of the hands (crossed ↔ uncrossed in Expt. 1; palm-up ↔ palm-down in Expt. 2) to determine the reference frame of tactile contextual cueing. In both experiments, target-distractor associations acquired during learning transferred to the test session when the placement of the target and distractors was held constant in anatomical, but not external, coordinates. In the latter, RTs were even slower for repeated displays. We conclude that tactile contextual learning is coded in an anatomical reference frame. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Tactile Cueing for Target Acquisition and Identification

DTIC Science & Technology

2005-09-01

method of coding tactile information, and the method of presenting elevation information were studied. Results: Subjects were divided into video game experienced...VGP) subjects and non- video game (NVGP) experienced subjects. VGPs showed a significantly lower’ target acquisition time with the 12...that video game players performed better with the highest level of tactile resolution, while non- video game players performed better with simpler pattern and a lower resolution display.

Improvement and decline in tactile discrimination behavior after cortical plasticity induced by passive tactile coactivation.

PubMed

Hodzic, Amra; Veit, Ralf; Karim, Ahmed A; Erb, Michael; Godde, Ben

2004-01-14

Perceptual learning can be induced by passive tactile coactivation without attention or reinforcement. We used functional MRI (fMRI) and psychophysics to investigate in detail the specificity of this type of learning for different tactile discrimination tasks and the underlying cortical reorganization. We found that a few hours of Hebbian coactivation evoked a significant increase of primary (SI) and secondary (SII) somatosensory cortical areas representing the stimulated body parts. The amount of plastic changes was strongly correlated with improvement in spatial discrimination performance. However, in the same subjects, frequency discrimination was impaired after coactivation, indicating that even maladaptive processes can be induced by intense passive sensory stimulation.

Cooperative processing in primary somatosensory cortex and posterior parietal cortex during tactile working memory.

PubMed

Ku, Yixuan; Zhao, Di; Bodner, Mark; Zhou, Yong-Di

2015-08-01

In the present study, causal roles of both the primary somatosensory cortex (SI) and the posterior parietal cortex (PPC) were investigated in a tactile unimodal working memory (WM) task. Individual magnetic resonance imaging-based single-pulse transcranial magnetic stimulation (spTMS) was applied, respectively, to the left SI (ipsilateral to tactile stimuli), right SI (contralateral to tactile stimuli) and right PPC (contralateral to tactile stimuli), while human participants were performing a tactile-tactile unimodal delayed matching-to-sample task. The time points of spTMS were 300, 600 and 900 ms after the onset of the tactile sample stimulus (duration: 200 ms). Compared with ipsilateral SI, application of spTMS over either contralateral SI or contralateral PPC at those time points significantly impaired the accuracy of task performance. Meanwhile, the deterioration in accuracy did not vary with the stimulating time points. Together, these results indicate that the tactile information is processed cooperatively by SI and PPC in the same hemisphere, starting from the early delay of the tactile unimodal WM task. This pattern of processing of tactile information is different from the pattern in tactile-visual cross-modal WM. In a tactile-visual cross-modal WM task, SI and PPC contribute to the processing sequentially, suggesting a process of sensory information transfer during the early delay between modalities. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Tactile communication using a CO(2) flux stimulation for blind or deafblind people.

PubMed

da Cunha, Jose Carlos; Bordignon, Luiz Alberto; Nohama, Percy

2010-01-01

This paper describes a tactile stimulation system for producing nonvisual image patterns to blind or deafblind people. The stimulator yields a CO(2) pulsatile flux directed to the user's skin throughout a needle that is coupled to a 2-D tactile plotter. The fluxtactile plotter operates with two step motor mounted on a wood structure, controlled by a program developed to produce alphanumerical characters and geometric figures of different size and speed, which will be used to investigate the psychophysical properties of this kind of tactile communication. CO(2) is provided by a cylinder that delivers a stable flux, which is converted to a pulsatile mode through a high frequency solenoid valve that can chop it up to 1 kHz. Also, system temperature is controlled by a Peltier based device. Tests on the prototype indicate that the system is a valuable tool to investigate the psychophysical properties of the skin in response to stimulation by CO(2) jet, allowing a quantitative and qualitative analysis as a function of stimulation parameters. With the system developed, it was possible to plot the geometric figures proposed: triangles, rectangles and octagons, in different sizes and speeds, and verify the control of the frequency of CO(2) jet stimuli.

The effect of chronic low back pain on tactile suppression during back movements.

PubMed

Van Damme, Stefaan; Van Hulle, Lore; Danneels, Lieven; Spence, Charles; Crombez, Geert

2014-10-01

The aim of the present study was to examine whether tactile suppression, the phenomenon whereby tactile perception is suppressed during movement, would occur in the context of back movements. Of particular interest, it was investigated if tactile suppression in the back would be attenuated in those suffering from chronic low back pain. Individuals with chronic low back pain (N = 30) and a matched control group (N = 24) detected tactile stimuli on three possible locations (back, arm, chest) while performing a back or arm movement, or no movement. We hypothesized that the movements would induce tactile suppression, and that this effect would be largest for low-intense stimuli on the moving body part. We further hypothesized that, during back movements, tactile suppression on the back would be less pronounced in the chronic low back pain group than in the control group. The results showed the expected general tactile suppression effects. The hypothesis of back-specific attenuation of tactile suppression in the chronic low back pain group was not supported. However, back-specific tactile suppression in the chronic low back pain group was less pronounced in those who performed the back movements more slowly. Copyright © 2014 Elsevier B.V. All rights reserved.

Seeing the body distorts tactile size perception.

PubMed

Longo, Matthew R; Sadibolova, Renata

2013-03-01

Vision of the body modulates somatosensation, even when entirely non-informative about stimulation. For example, seeing the body increases tactile spatial acuity, but reduces acute pain. While previous results demonstrate that vision of the body modulates somatosensory sensitivity, it is unknown whether vision also affects metric properties of touch, and if so how. This study investigated how non-informative vision of the body modulates tactile size perception. We used the mirror box illusion to induce the illusion that participants were directly seeing their stimulated left hand, though they actually saw their reflected right hand. We manipulated whether participants: (a) had the illusion of directly seeing their stimulated left hand, (b) had the illusion of seeing a non-body object at the same location, or (c) looked directly at their non-stimulated right-hand. Participants made verbal estimates of the perceived distance between two tactile stimuli presented simultaneously to the dorsum of the left hand, either 20, 30, or 40mm apart. Vision of the body significantly reduced the perceived size of touch, compared to vision of the object or of the contralateral hand. In contrast, no apparent changes of perceived hand size were found. These results show that seeing the body distorts tactile size perception. Copyright © 2012 Elsevier B.V. All rights reserved.

Re-examining overlap between tactile and visual motion responses within hMT+ and STS

PubMed Central

Jiang, Fang; Beauchamp, Michael S.; Fine, Ione

2015-01-01

Here we examine overlap between tactile and visual motion BOLD responses within the human MT+ complex. Although several studies have reported tactile responses overlapping with hMT+, many used group average analyses, leaving it unclear whether these responses were restricted to sub-regions of hMT+. Moreover, previous studies either employed a tactile task or passive stimulation, leaving it unclear whether or not tactile responses in hMT+ are simply the consequence of visual imagery. Here we carried out a replication of one of the classic papers finding tactile responses in hMT+ (Hagen et al. 2002). We mapped MT and MST in individual subjects using visual field localizers. We then examined responses to tactile motion on the arm, either presented passively or in the presence of a visual task performed at fixation designed to minimize visualization of the concurrent tactile stimulation. To our surprise, without a visual task, we found only weak tactile motion responses in MT (6% of voxels showing tactile responses) and MST (2% of voxels). With an unrelated visual task designed to withdraw attention from the tactile modality, responses in MST reduced to almost nothing (<1% regions). Consistent with previous results, we did observe tactile responses in STS regions superior and anterior to hMT+. Despite the lack of individual overlap, group averaged responses produced strong spurious overlap between tactile and visual motion responses within hMT+ that resembled those observed in previous studies. The weak nature of tactile responses in hMT+ (and their abolition by withdrawal of attention) suggests that hMT+ may not serve as a supramodal motion processing module. PMID:26123373

A preliminary investigation of lumbar tactile acuity in yoga practitioners.

PubMed

Flaherty, Mary; Connolly, Martin

2014-01-01

Tactile acuity in the back relates to voluntary lumbo-pelvic control and is lower in chronic low back pain (CLBP) patients. Two-point discrimination (TPD) thresholds are higher, indicating decreased tactile acuity in patients with CLBP. Yoga has been shown to help relieve CLBP. This study investigated the hypothesis that regular practitioners of yoga have increased tactile acuity (i.e., lower TPD thresholds) when compared to matched controls who regularly perform gym-based (resistance training or aerobic-type) exercise. Tactile acuity in the low back was assessed using TPD in 16 long-term practitioners of yoga (5 Ashtanga, 5 Bikram, and 6 Iyengar practitioners) and 16 age- and gender-matched healthy controls who exercise (with weights and aerobic exercise). The yoga practitioners' TPD was lower than that of the exercisers, indicating greater tactile acuity in the low back. While there was no difference between the TPD of the practitioners of different yoga styles, the TPD of the Ashtanga yoga participants were significantly lower than those of the exercisers. The yogis whose main reasons to practice yoga were for "meditation or increased mindfulness" and for "well-being" showed a nonsignificant trend of higher tactile acuity than those who did yoga for "physical exercise." There was no association between TPD threshold and cumulative amount of yoga practice in terms of hours per week and years of experience. However, increased hours of exercise per week correlated with higher TPD. The findings suggest that there may be a relationship between yoga practice and enhanced tactile acuity in the low back.

Development of tactile sensory circuits in the CNS.

PubMed

Iwasato, Takuji; Erzurumlu, Reha S

2018-06-13

Molecular identification of neuronal types and genetic and imaging approaches to characterize their properties reveal morphological, physiological and dynamic aspects of sensory circuit development. Here we focus on the mouse tactile sensory circuitry, with particular emphasis on the main trigeminal pathway that connects the whiskers, the major tactile organ in rodents, to the neocortex. At each level of this pathway, neurogenesis, axonal elongation, pathfinding, target recognition and circuit reorganization including dendritic refinement of cortical layer 4 neurons occur contemporaneously and a multitude of molecular signals are used in differing combinations. We highlight recent advances in development of tactile circuitry and note gaps in our understanding. Copyright © 2018 Elsevier Ltd. All rights reserved.

Energy Systems Sensor Laboratory | Energy Systems Integration Facility |

Science.gov Websites

NREL Sensor Laboratory Energy Systems Sensor Laboratory The Energy Systems Integration Facility's Energy Systems Sensor Laboratory is designed to support research, development, testing, and evaluation of advanced hydrogen sensor technologies to support the needs of the emerging hydrogen

Health Monitoring System for Car Seat

NASA Technical Reports Server (NTRS)

Elrod, Susan Vinz (Inventor); Dabney, Richard W. (Inventor)

2004-01-01

A health monitoring system for use with a child car seat has sensors mounted in the seat to monitor one or more health conditions of the seat's occupant. A processor monitors the sensor's signals and generates status signals related to the monitored conditions. A transmitter wireless transmits the status signals to a remotely located receiver. A signaling device coupled to the receiver produces at least one sensory (e.g., visual, audible, tactile) output based on the status signals.

Reach Trajectories Characterize Tactile Localization for Sensorimotor Decision Making.

PubMed

Brandes, Janina; Heed, Tobias

2015-10-07

Spatial target information for movement planning appears to be coded in a gaze-centered reference frame. In touch, however, location is initially coded with reference to the skin. Therefore, the tactile spatial location must be derived by integrating skin location and posture. It has been suggested that this recoding is impaired when the limb is placed in the opposite hemispace, for example, by limb crossing. Here, human participants reached toward visual and tactile targets located at uncrossed and crossed feet in a sensorimotor decision task. We characterized stimulus recoding by analyzing the timing and spatial profile of hand reaches. For tactile targets at crossed feet, skin-based information implicates the incorrect side, and only recoded information points to the correct location. Participants initiated straight reaches and redirected the hand toward a target presented in midflight. Trajectories to visual targets were unaffected by foot crossing. In contrast, trajectories to tactile targets were redirected later with crossed than uncrossed feet. Reaches to crossed feet usually continued straight until they were directed toward the correct tactile target and were not biased toward the skin-based target location. Occasional, far deflections toward the incorrect target were most likely when this target was implicated by trial history. These results are inconsistent with the suggestion that spatial transformations in touch are impaired by limb crossing, but are consistent with tactile location being recoded rapidly and efficiently, followed by integration of skin-based and external information to specify the reach target. This process may be implemented in a bounded integrator framework. How do you touch yourself, for instance, to scratch an itch? The place you need to reach is defined by a sensation on the skin, but our bodies are flexible, so this skin location could be anywhere in 3D space. The movement toward the tactile sensation must therefore be specified

Acoustic Tactile Representation of Visual Information

NASA Astrophysics Data System (ADS)

Silva, Pubudu Madhawa

subjects. The results are evaluated in terms of accuracy and speed, and they demonstrate the advantages of spatial sound for guiding the scanning finger or pointer in shape perception, object localization, and layout exploration. We show that these advantages increase with the amount of detail (smaller object size) in the display. Our experimental results show that the proposed system outperforms the state of the art in shape perception, including variable friction displays. We also demonstrate that, even though they are currently available only as static overlays, raised dot patterns provide the best shape rendition in terms of both the accuracy and speed. Our experiments with layout rendering and perception demonstrate that simultaneous representation of objects, using the most effective approaches for directionality and distance rendering, approaches the optimal performance level provided by visual layout perception. Finally, experiments with the virtual cane and Venn diagram configurations demonstrate that the proposed techniques can be used effectively in simple but nontrivial real-world applications. One of the most important conclusions of our experiments is that there is a clear performance gap between experienced and inexperienced subjects, which indicates that there is a lot of room for improvement with appropriate and extensive training. By exploring a wide variety of design alternatives and focusing on different aspects of the acoustic-tactile interfaces, our results offer many valuable insights and great promise for the design of future systematic tests visually impaired and visually blocked subjects, utilizing the most effective configurations.

A Study on Immersion and Presence of a Portable Hand Haptic System for Immersive Virtual Reality

PubMed Central

Kim, Mingyu; Jeon, Changyu; Kim, Jinmo

2017-01-01

This paper proposes a portable hand haptic system using Leap Motion as a haptic interface that can be used in various virtual reality (VR) applications. The proposed hand haptic system was designed as an Arduino-based sensor architecture to enable a variety of tactile senses at low cost, and is also equipped with a portable wristband. As a haptic system designed for tactile feedback, the proposed system first identifies the left and right hands and then sends tactile senses (vibration and heat) to each fingertip (thumb and index finger). It is incorporated into a wearable band-type system, making its use easy and convenient. Next, hand motion is accurately captured using the sensor of the hand tracking system and is used for virtual object control, thus achieving interaction that enhances immersion. A VR application was designed with the purpose of testing the immersion and presence aspects of the proposed system. Lastly, technical and statistical tests were carried out to assess whether the proposed haptic system can provide a new immersive presence to users. According to the results of the presence questionnaire and the simulator sickness questionnaire, we confirmed that the proposed hand haptic system, in comparison to the existing interaction that uses only the hand tracking system, provided greater presence and a more immersive environment in the virtual reality. PMID:28513545

A Study on Immersion and Presence of a Portable Hand Haptic System for Immersive Virtual Reality.

PubMed

Kim, Mingyu; Jeon, Changyu; Kim, Jinmo

2017-05-17

This paper proposes a portable hand haptic system using Leap Motion as a haptic interface that can be used in various virtual reality (VR) applications. The proposed hand haptic system was designed as an Arduino-based sensor architecture to enable a variety of tactile senses at low cost, and is also equipped with a portable wristband. As a haptic system designed for tactile feedback, the proposed system first identifies the left and right hands and then sends tactile senses (vibration and heat) to each fingertip (thumb and index finger). It is incorporated into a wearable band-type system, making its use easy and convenient. Next, hand motion is accurately captured using the sensor of the hand tracking system and is used for virtual object control, thus achieving interaction that enhances immersion. A VR application was designed with the purpose of testing the immersion and presence aspects of the proposed system. Lastly, technical and statistical tests were carried out to assess whether the proposed haptic system can provide a new immersive presence to users. According to the results of the presence questionnaire and the simulator sickness questionnaire, we confirmed that the proposed hand haptic system, in comparison to the existing interaction that uses only the hand tracking system, provided greater presence and a more immersive environment in the virtual reality.

Nitrogen narcosis and tactile shape memory in low visibility.

PubMed

van Wijk, Charles H; Meintjes, W A J

2014-01-01

Commercial diving often occurs in low visibility, where divers are reliant on their tactile senses. This study examined the effect of nitrogen narcosis on tactile memory for shapes as well as the influence of psychological and biographical factors on this relationship. This crossover study tested 139 commercial divers in a dry hyperbaric chamber at 101.325 and 607.95 kPa (1 and 6 atmospheres absolute/atm abs). Divers memorized shapes while blindfolded, using their tactile senses only. Delayed recall was measured at the surface after each dive. Psychological and biographical data were also collected. A significant effect of hyperbaric pressure on tactile memory was demonstrated, and a further effect of sequence of testing found. Thus, divers' delayed shape recall deteriorated by 8% after learning material at depth, compared to learning on the surface. There were also significant but small effects of psychological and biographical markers on tactile memory performance, with lower trait anxiety associated with better recall, and lower education associated with poorer recall. The findings emphasize the importance of utilizing other forms of recording of events or objects at depth, particularly in conditions of low visibility during deeper diving, to aid memory encoding and subsequent recall at the surface.

Toward a tactile language for human-robot interaction: two studies of tacton learning and performance.

PubMed

Barber, Daniel J; Reinerman-Jones, Lauren E; Matthews, Gerald

2015-05-01

Two experiments were performed to investigate the feasibility for robot-to-human communication of a tactile language using a lexicon of standardized tactons (tactile icons) within a sentence. Improvements in autonomous systems technology and a growing demand within military operations are spurring interest in communication via vibrotactile displays. Tactile communication may become an important element of human-robot interaction (HRI), but it requires the development of messaging capabilities approaching the communication power of the speech and visual signals used in the military. In Experiment 1 (N = 38), we trained participants to identify sets of directional, dynamic, and static tactons and tested performance and workload following training. In Experiment 2 (N = 76), we introduced an extended training procedure and tested participants' ability to correctly identify two-tacton phrases. We also investigated the impact of multitasking on performance and workload. Individual difference factors were assessed. Experiment 1 showed that participants found dynamic and static tactons difficult to learn, but the enhanced training procedure in Experiment 2 produced competency in performance for all tacton categories. Participants in the latter study also performed well on two-tacton phrases and when multitasking. However, some deficits in performance and elevation of workload were observed. Spatial ability predicted some aspects of performance in both studies. Participants may be trained to identify both single tactons and tacton phrases, demonstrating the feasibility of developing a tactile language for HRI. Tactile communication may be incorporated into multi-modal communication systems for HRI. It also has potential for human-human communication in challenging environments. © 2014, Human Factors and Ergonomics Society.

Good vibrations: tactile feedback in support of attention allocation and human-automation coordination in event-driven domains.

PubMed

Sklar, A E; Sarter, N B

1999-12-01

Observed breakdowns in human-machine communication can be explained, in part, by the nature of current automation feedback, which relies heavily on focal visual attention. Such feedback is not well suited for capturing attention in case of unexpected changes and events or for supporting the parallel processing of large amounts of data in complex domains. As suggested by multiple-resource theory, one possible solution to this problem is to distribute information across various sensory modalities. A simulator study was conducted to compare the effectiveness of visual, tactile, and redundant visual and tactile cues for indicating unexpected changes in the status of an automated cockpit system. Both tactile conditions resulted in higher detection rates for, and faster response times to, uncommanded mode transitions. Tactile feedback did not interfere with, nor was its effectiveness affected by, the performance of concurrent visual tasks. The observed improvement in task-sharing performance indicates that the introduction of tactile feedback is a promising avenue toward better supporting human-machine communication in event-driven, information-rich domains.

Evolutionary Specialization of Tactile Perception in Vertebrates.

PubMed

Schneider, Eve R; Gracheva, Elena O; Bagriantsev, Slav N

2016-05-01

Evolution has endowed vertebrates with the remarkable tactile ability to explore the world through the perception of physical force. Yet the sense of touch remains one of the least well understood senses at the cellular and molecular level. Vertebrates specializing in tactile perception can highlight general principles of mechanotransduction. Here, we review cellular and molecular adaptations that underlie the sense of touch in typical and acutely mechanosensitive vertebrates. ©2016 Int. Union Physiol. Sci./Am. Physiol. Soc.

Displacement sensors using soft magnetostrictive alloys

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

Hristoforou, E.; Reilly, R.E.

1994-09-01

The authors report results on the response of a family of displacement sensors, which are based on the magnetostrictive delay line (MDL) technique, using current conductor orthogonal to the MDL. Such sensing technique is based on the change of the magnetic circuit and the acoustic stress point of origin due to the displacement of a soft magnetic material above it. Integrated arrays of sensors can be obtained due to the acoustic delay line technique and they can be used as tactile arrays, digitizers or devices for medical application (gait analysis etc.), while absence of hysteresis and low cost of manufacturingmore » make them competent in this sector of sensor market.« less

Where are my hands? Influence of limb posture on tactile extinction.

PubMed

Auclair, Laurent; Barra, Julien; Raibaut, Patrick

2012-05-01

Tactile localization on the skin involves both a somatotopic and a postural schema (body-schema) representation. The present study determines the extent to which body posture influences tactile perception in right-brain-damaged patients. In a first set of experiments, patients were asked to detect single tactile stimulation delivered to their left or right hands or to both hands simultaneously (double stimulation) in different arm postures. Only patients who had no difficulty localizing single and double tactile stimulations when their hands were placed in anatomic position were tested. Participant's hands were crossed, one over the other, and the tactile stimuli were delivered either to the hand (beyond the crossing point, Experiment 1) or to the forearm (before the crossing point, Experiment 2). In Experiment 3, the left hand was placed in the right hemispace and the right hand in the left hemispace without crossing over (opposite condition). In a second set of experiments, patients were asked to detect stimulation delivered to the forefinger. The fingers were crossed, one over the other at the level of the middle phalanx, and stimuli were delivered either beyond or before the crossing point. In all experimental conditions, control participants performed at ceiling. We observed a left-hand tactile extinction on double stimulation in the crossed condition. These results suggest that tactile stimuli can be encoded based on multiple specific body-part representations rather than on an integrated body-schema representation.

Tactile Acuity Charts: A Reliable Measure of Spatial Acuity

PubMed Central

Bruns, Patrick; Camargo, Carlos J.; Campanella, Humberto; Esteve, Jaume; Dinse, Hubert R.; Röder, Brigitte

2014-01-01

For assessing tactile spatial resolution it has recently been recommended to use tactile acuity charts which follow the design principles of the Snellen letter charts for visual acuity and involve active touch. However, it is currently unknown whether acuity thresholds obtained with this newly developed psychophysical procedure are in accordance with established measures of tactile acuity that involve passive contact with fixed duration and control of contact force. Here we directly compared tactile acuity thresholds obtained with the acuity charts to traditional two-point and grating orientation thresholds in a group of young healthy adults. For this purpose, two types of charts, using either Braille-like dot patterns or embossed Landolt rings with different orientations, were adapted from previous studies. Measurements with the two types of charts were equivalent, but generally more reliable with the dot pattern chart. A comparison with the two-point and grating orientation task data showed that the test-retest reliability of the acuity chart measurements after one week was superior to that of the passive methods. Individual thresholds obtained with the acuity charts agreed reasonably with the grating orientation threshold, but less so with the two-point threshold that yielded relatively distinct acuity estimates compared to the other methods. This potentially considerable amount of mismatch between different measures of tactile acuity suggests that tactile spatial resolution is a complex entity that should ideally be measured with different methods in parallel. The simple test procedure and high reliability of the acuity charts makes them a promising complement and alternative to the traditional two-point and grating orientation thresholds. PMID:24504346

Micromachined actuators/sensors for intratubular positioning/steering

DOEpatents

Lee, Abraham P.; Krulevitch, Peter A.; Northrup, M. Allen; Trevino, Jimmy C.

1998-01-01

Micromachined thin film cantilever actuators having means for individually controlling the deflection of the cantilevers, valve members, and rudders for steering same through blood vessels, or positioning same within a blood vessel, for example. Such cantilever actuators include tactile sensor arrays mounted on a catheter or guide wire tip for navigation and tissues identification, shape-memory alloy film based catheter/guide wire steering mechanisms, and rudder-based steering devices that allow the selective actuation of rudders that use the flowing blood itself to help direct the catheter direction through the blood vessel. While particularly adapted for medical applications, these cantilever actuators can be used for steering through piping and tubing systems.

Wearable sensor systems for infants.

PubMed

Zhu, Zhihua; Liu, Tao; Li, Guangyi; Li, Tong; Inoue, Yoshio

2015-02-05

Continuous health status monitoring of infants is achieved with the development and fusion of wearable sensing technologies, wireless communication techniques and a low energy-consumption microprocessor with high performance data processing algorithms. As a clinical tool applied in the constant monitoring of physiological parameters of infants, wearable sensor systems for infants are able to transmit the information obtained inside an infant's body to clinicians or parents. Moreover, such systems with integrated sensors can perceive external threats such as falling or drowning and warn parents immediately. Firstly, the paper reviews some available wearable sensor systems for infants; secondly, we introduce the different modules of the framework in the sensor systems; lastly, the methods and techniques applied in the wearable sensor systems are summarized and discussed. The latest research and achievements have been highlighted in this paper and the meaningful applications in healthcare and behavior analysis are also presented. Moreover, we give a lucid perspective of the development of wearable sensor systems for infants in the future.

Wearable Sensor Systems for Infants

PubMed Central

Zhu, Zhihua; Liu, Tao; Li, Guangyi; Li, Tong; Inoue, Yoshio

2015-01-01

Continuous health status monitoring of infants is achieved with the development and fusion of wearable sensing technologies, wireless communication techniques and a low energy-consumption microprocessor with high performance data processing algorithms. As a clinical tool applied in the constant monitoring of physiological parameters of infants, wearable sensor systems for infants are able to transmit the information obtained inside an infant's body to clinicians or parents. Moreover, such systems with integrated sensors can perceive external threats such as falling or drowning and warn parents immediately. Firstly, the paper reviews some available wearable sensor systems for infants; secondly, we introduce the different modules of the framework in the sensor systems; lastly, the methods and techniques applied in the wearable sensor systems are summarized and discussed. The latest research and achievements have been highlighted in this paper and the meaningful applications in healthcare and behavior analysis are also presented. Moreover, we give a lucid perspective of the development of wearable sensor systems for infants in the future. PMID:25664432

Soldier systems sensor fusion

NASA Astrophysics Data System (ADS)

Brubaker, Kathryne M.

1998-08-01

This paper addresses sensor fusion and its applications in emerging Soldier Systems integration and the unique challenges associated with the human platform. Technology that,provides the highest operational payoff in a lightweight warrior system must not only have enhanced capabilities, but have low power components resulting in order of magnitude reductions coupled with significant cost reductions. These reductions in power and cost will be achieved through partnership with industry and leveraging of commercial state of the art advancements in microelectronics and power sources. As new generation of full solution fire control systems (to include temperature, wind and range sensors) and target acquisition systems will accompany a new generation of individual combat weapons and upgrade existing weapon systems. Advanced lightweight thermal, IR, laser and video senors will be used for surveillance, target acquisition, imaging and combat identification applications. Multifunctional sensors will provide embedded training features in combat configurations allowing the soldier to 'train as he fights' without the traditional cost and weight penalties associated with separate systems. Personal status monitors (detecting pulse, respiration rate, muscle fatigue, core temperature, etc.) will provide commanders and highest echelons instantaneous medical data. Seamless integration of GPS and dead reckoning (compass and pedometer) and/or inertial sensors will aid navigation and increase position accuracy. Improved sensors and processing capability will provide earlier detection of battlefield hazards such as mines, enemy lasers and NBC (nuclear, biological, chemical) agents. Via the digitized network the situational awareness database will automatically be updated with weapon, medical, position and battlefield hazard data. Soldier Systems Sensor Fusion will ultimately establish each individual soldier as an individual sensor on the battlefield.

Transfer of tactile perceptual learning to untrained neighboring fingers reflects natural use relationships

PubMed Central

Harrar, Vanessa; Oliver, Jonathan; Johansen-Berg, Heidi; Spence, Charles

2015-01-01

Tactile learning transfers from trained to untrained fingers in a pattern that reflects overlap between the representations of fingers in the somatosensory system (e.g., neurons with multifinger receptive fields). While physical proximity on the body is known to determine the topography of somatosensory representations, tactile coactivation is also an established organizing principle of somatosensory topography. In this study we investigated whether tactile coactivation, induced by habitual inter-finger cooperative use (use pattern), shapes inter-finger overlap. To this end, we used psychophysics to compare the transfer of tactile learning from the middle finger to its adjacent fingers. This allowed us to compare transfer to two fingers that are both physically and cortically adjacent to the middle finger but have differing use patterns. Specifically, the middle finger is used more frequently with the ring than with the index finger. We predicted this should lead to greater representational overlap between the former than the latter pair. Furthermore, this difference in overlap should be reflected in differential learning transfer from the middle to index vs. ring fingers. Subsequently, we predicted temporary learning-related changes in the middle finger's representation (e.g., cortical magnification) would cause transient interference in perceptual thresholds of the ring, but not the index, finger. Supporting this, longitudinal analysis revealed a divergence where learning transfer was fast to the index finger but relatively delayed to the ring finger. Our results support the theory that tactile coactivation patterns between digits affect their topographic relationships. Our findings emphasize how action shapes perception and somatosensory organization. PMID:26631145

Transfer of tactile perceptual learning to untrained neighboring fingers reflects natural use relationships.

PubMed

Dempsey-Jones, Harriet; Harrar, Vanessa; Oliver, Jonathan; Johansen-Berg, Heidi; Spence, Charles; Makin, Tamar R

2016-03-01

Tactile learning transfers from trained to untrained fingers in a pattern that reflects overlap between the representations of fingers in the somatosensory system (e.g., neurons with multifinger receptive fields). While physical proximity on the body is known to determine the topography of somatosensory representations, tactile coactivation is also an established organizing principle of somatosensory topography. In this study we investigated whether tactile coactivation, induced by habitual inter-finger cooperative use (use pattern), shapes inter-finger overlap. To this end, we used psychophysics to compare the transfer of tactile learning from the middle finger to its adjacent fingers. This allowed us to compare transfer to two fingers that are both physically and cortically adjacent to the middle finger but have differing use patterns. Specifically, the middle finger is used more frequently with the ring than with the index finger. We predicted this should lead to greater representational overlap between the former than the latter pair. Furthermore, this difference in overlap should be reflected in differential learning transfer from the middle to index vs. ring fingers. Subsequently, we predicted temporary learning-related changes in the middle finger's representation (e.g., cortical magnification) would cause transient interference in perceptual thresholds of the ring, but not the index, finger. Supporting this, longitudinal analysis revealed a divergence where learning transfer was fast to the index finger but relatively delayed to the ring finger. Our results support the theory that tactile coactivation patterns between digits affect their topographic relationships. Our findings emphasize how action shapes perception and somatosensory organization. Copyright © 2016 the American Physiological Society.

Tapered whiskers are required for active tactile sensation.

PubMed

Hires, Samuel Andrew; Pammer, Lorenz; Svoboda, Karel; Golomb, David

2013-11-19

Many mammals forage and burrow in dark constrained spaces. Touch through facial whiskers is important during these activities, but the close quarters makes whisker deployment challenging. The diverse shapes of facial whiskers reflect distinct ecological niches. Rodent whiskers are conical, often with a remarkably linear taper. Here we use theoretical and experimental methods to analyze interactions of mouse whiskers with objects. When pushed into objects, conical whiskers suddenly slip at a critical angle. In contrast, cylindrical whiskers do not slip for biologically plausible movements. Conical whiskers sweep across objects and textures in characteristic sequences of brief sticks and slips, which provide information about the tactile world. In contrast, cylindrical whiskers stick and remain stuck, even when sweeping across fine textures. Thus the conical whisker structure is adaptive for sensor mobility in constrained environments and in feature extraction during active haptic exploration of objects and surfaces. DOI: http://dx.doi.org/10.7554/eLife.01350.001.

Recent Progress of Self-Powered Sensing Systems for Wearable Electronics.

PubMed

Lou, Zheng; Li, La; Wang, Lili; Shen, Guozhen

2017-12-01

Wearable/flexible electronic sensing systems are considered to be one of the key technologies in the next generation of smart personal electronics. To realize personal portable devices with mobile electronics application, i.e., wearable electronic sensors that can work sustainably and continuously without an external power supply are highly desired. The recent progress and advantages of wearable self-powered electronic sensing systems for mobile or personal attachable health monitoring applications are presented. An overview of various types of wearable electronic sensors, including flexible tactile sensors, wearable image sensor array, biological and chemical sensor, temperature sensors, and multifunctional integrated sensing systems is provided. Self-powered sensing systems with integrated energy units are then discussed, separated as energy harvesting self-powered sensing systems, energy storage integrated sensing systems, and all-in-on integrated sensing systems. Finally, the future perspectives of self-powered sensing systems for wearable electronics are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Learning in Tactile Channels

ERIC Educational Resources Information Center

Gescheider, George A.; Wright, John H.

2012-01-01

Vibrotactile intensity-discrimination thresholds for sinusoidal stimuli applied to the thenar eminence of the hand declined as a function of practice. However, improvement was confined to the tactile information-processing channel in which learning had occurred. Specifically, improvements in performance with training within the Pacinian-corpuscle…

Can tactile sensory processing differentiate between children with autistic disorder and asperger's disorder?

PubMed

Ghanizadeh, Ahmad

2011-05-01

There are debates whether autistic disorder (autism) and Asperger's disorder are two distinct disorders. Moreover, interventional sensory occupational therapy should consider the clinical characteristics of patients. Already, commonalities and differences between Asperger's disorder and autistic disorder are not well studied. The aim of this study is to compare tactile sensory function of children with autistic disorder and children with Asperger's disorder. Tactile sensory function was compared between 36 children with autism and 19 children with Asperger's disorder. The two disorders were diagnosed based on Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision. The parent-reported Tactile Dysfunction Checklist was used to assess the three aspects of hypersensitivity, hyposensitivity, and poor tactile perception and discrimination. Developmental coordination was also assessed. Developmental coordination problems total score was not associated with group. The mean (standard deviation) score of tactile hyper-responsivity was not different between the groups. Tactile hyporesponsivity and poor tactile perception and discrimination scores were statistically higher in autistic disorder than Asperger's disorder group. These results for the first time indicated that at least some aspects of tactile perception can differentiate these two disorders. Children with autistic disorder have more tactile sensory seeking behaviors than children with Asperger's disorder. Moreover, the ability of children with autistic disorder for tactile discrimination and sensory perception is less than those with Asperger's disorder. Interventional sensory therapy in children with autistic disorder should have some characteristics that can be different and specific for children with Asperger's disorder. Formal intelligence quotient testing was not performed on all of the children evaluated, which is a limitation to this study. In some cases, a clinical estimation of

Robo-Psychophysics: Extracting Behaviorally Relevant Features from the Output of Sensors on a Prosthetic Finger.

PubMed

Delhaye, Benoit P; Schluter, Erik W; Bensmaia, Sliman J

2016-01-01

Efforts are underway to restore sensorimotor function in amputees and tetraplegic patients using anthropomorphic robotic hands. For this approach to be clinically viable, sensory signals from the hand must be relayed back to the patient. To convey tactile feedback necessary for object manipulation, behaviorally relevant information must be extracted in real time from the output of sensors on the prosthesis. In the present study, we recorded the sensor output from a state-of-the-art bionic finger during the presentation of different tactile stimuli, including punctate indentations and scanned textures. Furthermore, the parameters of stimulus delivery (location, speed, direction, indentation depth, and surface texture) were systematically varied. We developed simple decoders to extract behaviorally relevant variables from the sensor output and assessed the degree to which these algorithms could reliably extract these different types of sensory information across different conditions of stimulus delivery. We then compared the performance of the decoders to that of humans in analogous psychophysical experiments. We show that straightforward decoders can extract behaviorally relevant features accurately from the sensor output and most of them outperform humans.

Development of a tactile display with 5 mm resolution using an array of magnetorheological fluid

NASA Astrophysics Data System (ADS)

Ishizuka, Hiroki; Miki, Norihisa

2017-06-01

In this study, we demonstrate the design and evaluation of a stiffness tactile display using a magnetorheological (MR) fluid. The tactile display is based on the change in mechanical properties under an external magnetic field. In the tactile display, the MR fluid is encapsulated in chambers of 3 mm diameter and arranged at intervals of 2 mm. Magnetic fields were spatially applied to the tactile display using neodymium magnets of 3.5 mm diameter. The design and spatial magnetic field application enable the tactile display to present stiff dots of 5 mm resolution. We confirmed that the tactile display can present a spatial stiff dot and its pattern on the surface by compression experiments. Sensory evaluation revealed that the users were able to perceive the approximate position of the stiff dots. From the experiments, the tactile display has potential as a palpation tactile display and requires improvement to present various types of tissues.

Audio-Tactile Integration in Congenitally and Late Deaf Cochlear Implant Users

PubMed Central

Nava, Elena; Bottari, Davide; Villwock, Agnes; Fengler, Ineke; Büchner, Andreas; Lenarz, Thomas; Röder, Brigitte

2014-01-01

Several studies conducted in mammals and humans have shown that multisensory processing may be impaired following congenital sensory loss and in particular if no experience is achieved within specific early developmental time windows known as sensitive periods. In this study we investigated whether basic multisensory abilities are impaired in hearing-restored individuals with deafness acquired at different stages of development. To this aim, we tested congenitally and late deaf cochlear implant (CI) recipients, age-matched with two groups of hearing controls, on an audio-tactile redundancy paradigm, in which reaction times to unimodal and crossmodal redundant signals were measured. Our results showed that both congenitally and late deaf CI recipients were able to integrate audio-tactile stimuli, suggesting that congenital and acquired deafness does not prevent the development and recovery of basic multisensory processing. However, we found that congenitally deaf CI recipients had a lower multisensory gain compared to their matched controls, which may be explained by their faster responses to tactile stimuli. We discuss this finding in the context of reorganisation of the sensory systems following sensory loss and the possibility that these changes cannot be “rewired” through auditory reafferentation. PMID:24918766

Audio-tactile integration in congenitally and late deaf cochlear implant users.

PubMed

Nava, Elena; Bottari, Davide; Villwock, Agnes; Fengler, Ineke; Büchner, Andreas; Lenarz, Thomas; Röder, Brigitte

2014-01-01

Several studies conducted in mammals and humans have shown that multisensory processing may be impaired following congenital sensory loss and in particular if no experience is achieved within specific early developmental time windows known as sensitive periods. In this study we investigated whether basic multisensory abilities are impaired in hearing-restored individuals with deafness acquired at different stages of development. To this aim, we tested congenitally and late deaf cochlear implant (CI) recipients, age-matched with two groups of hearing controls, on an audio-tactile redundancy paradigm, in which reaction times to unimodal and crossmodal redundant signals were measured. Our results showed that both congenitally and late deaf CI recipients were able to integrate audio-tactile stimuli, suggesting that congenital and acquired deafness does not prevent the development and recovery of basic multisensory processing. However, we found that congenitally deaf CI recipients had a lower multisensory gain compared to their matched controls, which may be explained by their faster responses to tactile stimuli. We discuss this finding in the context of reorganisation of the sensory systems following sensory loss and the possibility that these changes cannot be "rewired" through auditory reafferentation.

E-Pad: a comfortable electrocutaneous-based tactile feedback display

NASA Astrophysics Data System (ADS)

Wang, Jiabin; Zhao, Lu; Liu, Yue; Wang, Yongtian; Cai, Yi

2018-01-01

The devices with touchscreen are becoming more popular recently; however, most of them suffer from the crucial drawbacks of lacking accurate tactile feedback. A novel electrocutaneous-based tactile device with the name of E-pad is proposed to provide a dynamic and static low-voltage feedback for touchscreen. We optimize the key parameters of the output voltage and design custom-made hardwares to guarantee a comfortable user experience. Users could move their fingers freely across the touchscreen of the proposed device to really feel virtual objects. Two preliminary experiments are conducted to evaluate the interactive performance of the proposed device and the experimental results show that the proposed device can provide a comfortable and distinct tactile feedback.

Change of reference frame for tactile localization during child development.

PubMed

Pagel, Birthe; Heed, Tobias; Röder, Brigitte

2009-11-01

Temporal order judgements (TOJ) for two tactile stimuli, one presented to the left and one to the right hand, are less precise when the hands are crossed over the midline than when the hands are uncrossed. This 'crossed hand' effect has been considered as evidence for a remapping of tactile input into an external reference frame. Since late, but not early, blind individuals show such remapping, it has been hypothesized that the use of an external reference frame develops during childhood. Five- to 10-year-old children were therefore tested with the tactile TOJ task, both with uncrossed and crossed hands. Overall performance in the TOJ task improved with age. While children older than 5 1/2 years displayed a crossed hand effect, younger children did not. Therefore the use of an external reference frame for tactile, and possibly multisensory, localization seems to be acquired at age 5.

Multisensory effects on somatosensation: a trimodal visuo-vestibular-tactile interaction

PubMed Central

Kaliuzhna, Mariia; Ferrè, Elisa Raffaella; Herbelin, Bruno; Blanke, Olaf; Haggard, Patrick

2016-01-01

Vestibular information about self-motion is combined with other sensory signals. Previous research described both visuo-vestibular and vestibular-tactile bilateral interactions, but the simultaneous interaction between all three sensory modalities has not been explored. Here we exploit a previously reported visuo-vestibular integration to investigate multisensory effects on tactile sensitivity in humans. Tactile sensitivity was measured during passive whole body rotations alone or in conjunction with optic flow, creating either purely vestibular or visuo-vestibular sensations of self-motion. Our results demonstrate that tactile sensitivity is modulated by perceived self-motion, as provided by a combined visuo-vestibular percept, and not by the visual and vestibular cues independently. We propose a hierarchical multisensory interaction that underpins somatosensory modulation: visual and vestibular cues are first combined to produce a multisensory self-motion percept. Somatosensory processing is then enhanced according to the degree of perceived self-motion. PMID:27198907

A Tactile Stimulator for Studying Passive Shape Perception

PubMed Central

Lane, John W.; Fitzgerald, Paul J.; Yau, Jeffrey M.; Pembeci, Izzet; Hsiao, Steven S.

2009-01-01

We describe a computer-controlled tactile stimulator for use in human psychophysical and monkey neurophysiological studies of 3-D shape perception. The stimulator is constructed primarily of commercially available parts, as well as a few custom-built pieces for which we will supply diagrams upon request. There are two components to the stimulator: a tactile component and a hand positioner component. The tactile component consists of multiple stimulating units that move about in a Cartesian plane above the restrained hand. Each stimulating unit contains a servo-controlled linear motor with an attached small rotary stepper motor, allowing arbitrary stimulus shapes to contact the skin through vibration, static indentation, or scanning. The hand positioner component modifies the conformation of the restrained hand through a set of mechanical linkages under motorized control. The present design controls the amount of spread between digits two and three, the spread between digits four and three, and the degree to which digit three is flexed or extended, thereby simulating different conformations of the hand in contact with objects. This design is easily modified to suit the needs of the experimenter. Because the two components of the stimulator are independently controlled, the stimulator allows for parametric study of the mechanoreceptive and proprioceptive contributions to 3-D tactile shape perception. PMID:19800916

Tactile short-term memory in sensory-deprived individuals.

PubMed

Papagno, Costanza; Minniti, Giovanna; Mattavelli, Giulia C; Mantovan, Lara; Cecchetto, Carlo

2017-02-01

To verify whether loosing a sense or two has consequences on a spared sensory modality, namely touch, and whether these consequences depend on practice or are biologically determined, we investigated 13 deafblind participants, 16 deaf participants, 15 blind participants, and 13 matched normally sighted and hearing controls on a tactile short-term memory task, using checkerboard matrices of increasing length in which half of the squares were made up of a rough texture and half of a smooth one. Time of execution of a fixed matrix, number of correctly reproduced matrices, largest matrix correctly reproduced and tactile span were recorded. The three groups of sensory-deprived individuals did not differ in any measure, while blind and deaf participants outscored controls in all parameters except time of execution; the difference approached significance for deafblind people compared to controls only in one measure, namely correctly reproduced matrices. In blind and deafblind participants, performance negatively correlated with age of Braille acquisition, the older being the subject when acquiring Braille, the lower the performance, suggesting that practice plays a role. However, the fact that deaf participants, who did not share tactile experience, performed similarly to blind participants and significantly better than controls highlights that practice cannot be the only contribution to better tactile memory.

Tactile massage as a nursing intervention in child and adolescent psychiatry: nurses' experiences.

PubMed

Robertz, A-C; Rudolfsson, G

2016-10-01

WHAT IS KNOWN ABOUT THE SUBJECT?: There is little research on the implementation of tactile massage in child and adolescent psychiatry that describes children's and adolescents' experiences and outcomes. There is also limited knowledge of providing tactile massage in child and adolescent psychiatry. WHAT DOES THIS PAPER ADD TO EXISTING KNOWLEDGE?: This paper describes 10 nurses' experiences of tactile massage as a nursing intervention in child and adolescent psychiatry. The nurses considered tactile massage a non-verbal nursing intervention that could complement other available treatments. It reveals their reflections on the impact of tactile massage on their nursing and on themselves as a person, including the belief that they had developed deepened self-reflection and attentiveness. The nurses highlighted the importance of providing a trusting environment and collaborating with the children and adolescents. They both experienced and observed that tactile massage triggered various physical and mental processes in the children and adolescents, such as improvement in sleep disturbances, an ability to relax in body and mind and a deeper connectedness with their own bodies and feelings. The nurses described instructing next of kin in the use of tactile massage, which they believed could serve as a tool at home, mainly as a way for next of kin to help their children to relax, fall asleep more easily and to deepen connectedness. However, the nurses stressed the need to consider if it was appropriate or desired by the children and adolescents. WHAT ARE THE IMPLICATIONS FOR PRACTICE?: Tactile massage addresses the individual's emotional and physiological responses and could therefore bring holistic nursing to child and adolescent psychiatry. It could also help nurses in child and adolescent psychiatry to develop their attentiveness and sensitivity in acknowledging the needs of children and adolescents in psychiatric care. Introduction There is limited research on tactile

Visual detail about the body modulates tactile localisation biases.

PubMed

Margolis, Aaron N; Longo, Matthew R

2015-02-01

The localisation of tactile stimuli requires the integration of visual and somatosensory inputs within an internal representation of the body surface and is prone to consistent bias. Joints may play a role in segmenting such internal body representations, and may therefore influence tactile localisation biases, although the nature of this influence remains unclear. Here, we investigate the relationship between conceptual knowledge of joint locations and tactile localisation biases on the hand. In one task, participants localised tactile stimuli applied to the dorsum of their hand. A distal localisation bias was observed in all participants, consistent with previous results. We also manipulated the availability of visual information during this task, to determine whether the absence of this information could account for the distal bias observed here and by Mancini et al. (Neuropsychologia 49:1194-1201, 2011). The observed distal bias increased in magnitude when visual information was restricted, without a corresponding decrease in precision. In a separate task, the same participants indicated, from memory, knuckle locations on a silhouette image of their hand. Analogous distal biases were also seen in the knuckle localisation task. The accuracy of conceptual joint knowledge was not correlated with tactile localisation bias magnitude, although a similarity in observed bias direction suggests that both tasks may rely on a common, higher-order body representation. These results also suggest that distortions of conceptual body representation may be more common in healthy individuals than previously thought.

Short-Term Visual Deprivation, Tactile Acuity, and Haptic Solid Shape Discrimination

PubMed Central

Crabtree, Charles E.; Norman, J. Farley

2014-01-01

Previous psychophysical studies have reported conflicting results concerning the effects of short-term visual deprivation upon tactile acuity. Some studies have found that 45 to 90 minutes of total light deprivation produce significant improvements in participants' tactile acuity as measured with a grating orientation discrimination task. In contrast, a single 2011 study found no such improvement while attempting to replicate these earlier findings. A primary goal of the current experiment was to resolve this discrepancy in the literature by evaluating the effects of a 90-minute period of total light deprivation upon tactile grating orientation discrimination. We also evaluated the potential effect of short-term deprivation upon haptic 3-D shape discrimination using a set of naturally-shaped solid objects. According to previous research, short-term deprivation enhances performance in a tactile 2-D shape discrimination task – perhaps a similar improvement also occurs for haptic 3-D shape discrimination. The results of the current investigation demonstrate that not only does short-term visual deprivation not enhance tactile acuity, it additionally has no effect upon haptic 3-D shape discrimination. While visual deprivation had no effect in our study, there was a significant effect of experience and learning for the grating orientation task – the participants' tactile acuity improved over time, independent of whether they had, or had not, experienced visual deprivation. PMID:25397327

Short-term visual deprivation, tactile acuity, and haptic solid shape discrimination.

PubMed

Crabtree, Charles E; Norman, J Farley

2014-01-01

Previous psychophysical studies have reported conflicting results concerning the effects of short-term visual deprivation upon tactile acuity. Some studies have found that 45 to 90 minutes of total light deprivation produce significant improvements in participants' tactile acuity as measured with a grating orientation discrimination task. In contrast, a single 2011 study found no such improvement while attempting to replicate these earlier findings. A primary goal of the current experiment was to resolve this discrepancy in the literature by evaluating the effects of a 90-minute period of total light deprivation upon tactile grating orientation discrimination. We also evaluated the potential effect of short-term deprivation upon haptic 3-D shape discrimination using a set of naturally-shaped solid objects. According to previous research, short-term deprivation enhances performance in a tactile 2-D shape discrimination task - perhaps a similar improvement also occurs for haptic 3-D shape discrimination. The results of the current investigation demonstrate that not only does short-term visual deprivation not enhance tactile acuity, it additionally has no effect upon haptic 3-D shape discrimination. While visual deprivation had no effect in our study, there was a significant effect of experience and learning for the grating orientation task - the participants' tactile acuity improved over time, independent of whether they had, or had not, experienced visual deprivation.

Concurrent emotional pictures modulate temporal order judgments of spatially separated audio-tactile stimuli.

PubMed

Jia, Lina; Shi, Zhuanghua; Zang, Xuelian; Müller, Hermann J

2013-11-06

Although attention can be captured toward high-arousal stimuli, little is known about how perceiving emotion in one modality influences the temporal processing of non-emotional stimuli in other modalities. We addressed this issue by presenting observers spatially uninformative emotional pictures while they performed an audio-tactile temporal-order judgment (TOJ) task. In Experiment 1, audio-tactile stimuli were presented at the same location straight ahead of the participants, who had to judge "which modality came first?". In Experiments 2 and 3, the audio-tactile stimuli were delivered one to the left and the other to the right side, and participants had to judge "which side came first?". We found both negative and positive high-arousal pictures to significantly bias TOJs towards the tactile and away from the auditory event when the audio-tactile stimuli were spatially separated; by contrast, there was no such bias when the audio-tactile stimuli originated from the same location. To further examine whether this bias is attributable to the emotional meanings conveyed by the pictures or to their high arousal effect, we compared and contrasted the influences of near-body threat vs. remote threat (emotional) pictures on audio-tactile TOJs in Experiment 3. The bias manifested only in the near-body threat condition. Taken together, the findings indicate that visual stimuli conveying meanings of near-body interaction activate a sensorimotor functional link prioritizing the processing of tactile over auditory signals when these signals are spatially separated. In contrast, audio-tactile signals from the same location engender strong crossmodal integration, thus counteracting modality-based attentional shifts induced by the emotional pictures. © 2013 Published by Elsevier B.V.

Exploring the Invisible Universe: A Tactile and Braille Exhibit of Astronomical Images

NASA Astrophysics Data System (ADS)

Arcand, K. K.; Watzke, M.; de Pree, C.

2010-06-01

A tactile/Braille exhibit for the visually impaired community in the USA was launched in July 2009. The exhibit is part of the global From Earth to the Universe (FETTU) project, a Cornerstone of the International Year of Astronomy 2009. The science content of the travelling tactile/Braille exhibit includes explanations of our Sun, Eta Carinae, the Crab Nebula, the Whirlpool Galaxy and the electromagnetic spectrum, and was adapted from the tactile/Braille book Touch the Invisible Sky. We present some of the early observations and findings on the tactile/Braille FETTU exhibit. The new exhibit opens a wider door to experiencing and understanding astronomy for the underserved visually impaired population.

Establishing Auditory-Tactile-Visual Equivalence Classes in Children with Autism and Developmental Delays

ERIC Educational Resources Information Center

Mullen, Stuart; Dixon, Mark R.; Belisle, Jordan; Stanley, Caleb

2017-01-01

The current study sought to evaluate the efficacy of a stimulus equivalence training procedure in establishing auditory-tactile-visual stimulus classes with 2 children with autism and developmental delays. Participants were exposed to vocal-tactile (A-B) and tactile-picture (B-C) conditional discrimination training and were tested for the…

Tactile Perception in Adults with Autism: A Multidimensional Psychophysical Study

ERIC Educational Resources Information Center

Cascio, Carissa; McGlone, Francis; Folger, Stephen; Tannan, Vinay; Baranek, Grace; Pelphrey, Kevin A.; Essick, Gregory

2008-01-01

Although sensory problems, including unusual tactile sensitivity, are heavily associated with autism, there is a dearth of rigorous psychophysical research. We compared tactile sensation in adults with autism to controls on the palm and forearm, the latter innervated by low-threshold unmyelinated afferents subserving a social/affiliative…

Functional consequences of experience-dependent plasticity on tactile perception following perceptual learning

PubMed Central

Trzcinski, Natalie K; Gomez-Ramirez, Manuel; Hsiao, Steven S.

2016-01-01

Continuous training enhances perceptual discrimination and promotes neural changes in areas encoding the experienced stimuli. This type of experience-dependent plasticity has been demonstrated in several sensory and motor systems. Particularly, non-human primates trained to detect consecutive tactile bar indentations across multiple digits showed expanded excitatory receptive fields (RFs) in somatosensory cortex. However, the perceptual implications of these anatomical changes remain undetermined. Here, we trained human participants for nine days on a tactile task that promoted expansion of multi-digit RFs. Participants were required to detect consecutive indentations of bar stimuli spanning multiple digits. Throughout the training regime we tracked participants’ discrimination thresholds on spatial (grating orientation) and temporal tasks on the trained and untrained hands in separate sessions. We hypothesized that training on the multi-digit task would decrease perceptual thresholds on tasks that require stimulus processing across multiple digits, while also increasing thresholds on tasks requiring discrimination on single digits. We observed an increase in orientation thresholds on a single-digit. Importantly, this effect was selective for the stimulus orientation and hand used during multi-digit training. We also found that temporal acuity between digits improved across trained digits, suggesting that discriminating the temporal order of multi-digit stimuli can transfer to temporal discrimination of other tactile stimuli. These results suggest that experience-dependent plasticity following perceptual learning improves and interferes with tactile abilities in manners predictive of the task and stimulus features used during training. PMID:27422224

When Content Matters: The Role of Processing Code in Tactile Display Design.

PubMed

Ferris, Thomas K; Sarter, Nadine

2010-01-01

The distribution of tasks and stimuli across multiple modalities has been proposed as a means to support multitasking in data-rich environments. Recently, the tactile channel and, more specifically, communication via the use of tactile/haptic icons have received considerable interest. Past research has examined primarily the impact of concurrent task modality on the effectiveness of tactile information presentation. However, it is not well known to what extent the interpretation of iconic tactile patterns is affected by another attribute of information: the information processing codes of concurrent tasks. In two driving simulation studies (n = 25 for each), participants decoded icons composed of either spatial or nonspatial patterns of vibrations (engaging spatial and nonspatial processing code resources, respectively) while concurrently interpreting spatial or nonspatial visual task stimuli. As predicted by Multiple Resource Theory, performance was significantly worse (approximately 5-10 percent worse) when the tactile icons and visual tasks engaged the same processing code, with the overall worst performance in the spatial-spatial task pairing. The findings from these studies contribute to an improved understanding of information processing and can serve as input to multidimensional quantitative models of timesharing performance. From an applied perspective, the results suggest that competition for processing code resources warrants consideration, alongside other factors such as the naturalness of signal-message mapping, when designing iconic tactile displays. Nonspatially encoded tactile icons may be preferable in environments which already rely heavily on spatial processing, such as car cockpits.

Exploring potential social influences on brain potentials during anticipation of tactile stimulation.

PubMed

Shen, Guannan; Saby, Joni N; Drew, Ashley R; Marshall, Peter J

2017-03-15

This study explored interpersonal influences on electrophysiological responses during the anticipation of tactile stimulation. It is well-known that broad, negative-going potentials are present in the event-related potential (ERP) between a forewarning cue and a tactile stimulus. It has also been shown that the alpha-range mu rhythm shows a lateralized desynchronization over central electrode sites during anticipation of tactile stimulation of the hand. The current study used a tactile discrimination task in which a visual cue signaled that an upcoming stimulus would either be delivered 1500ms later to the participant's hand, to a task partner's hand, or to neither person. For the condition in which participants anticipated the tactile stimulation to their own hand, a negative potential (contingent negative variation, CNV) was observed in the ERP at central sites in the 1000ms prior to the tactile stimulus. Significant mu rhythm desynchronization was also present in the same time window. The magnitudes of the ERPs and of the mu desynchronization were greater in the contralateral than in the ipsilateral hemisphere prior to right hand stimulation. Similar ERP and EEG changes were not present when the visual cue indicated that stimulation would be delivered to the task partner or to neither person. The absence of social influences during anticipation of tactile stimulation, and the relationship between the two brain signatures of anticipatory attention (CNV and mu rhythm) are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Correlation of neural activity with behavioral kinematics reveals distinct sensory encoding and evidence accumulation processes during active tactile sensing.

PubMed

Delis, Ioannis; Dmochowski, Jacek P; Sajda, Paul; Wang, Qi

2018-07-15

Many real-world decisions rely on active sensing, a dynamic process for directing our sensors (e.g. eyes or fingers) across a stimulus to maximize information gain. Though ecologically pervasive, limited work has focused on identifying neural correlates of the active sensing process. In tactile perception, we often make decisions about an object/surface by actively exploring its shape/texture. Here we investigate the neural correlates of active tactile decision-making by simultaneously measuring electroencephalography (EEG) and finger kinematics while subjects interrogated a haptic surface to make perceptual judgments. Since sensorimotor behavior underlies decision formation in active sensing tasks, we hypothesized that the neural correlates of decision-related processes would be detectable by relating active sensing to neural activity. Novel brain-behavior correlation analysis revealed that three distinct EEG components, localizing to right-lateralized occipital cortex (LOC), middle frontal gyrus (MFG), and supplementary motor area (SMA), respectively, were coupled with active sensing as their activity significantly correlated with finger kinematics. To probe the functional role of these components, we fit their single-trial-couplings to decision-making performance using a hierarchical-drift-diffusion-model (HDDM), revealing that the LOC modulated the encoding of the tactile stimulus whereas the MFG predicted the rate of information integration towards a choice. Interestingly, the MFG disappeared from components uncovered from control subjects performing active sensing but not required to make perceptual decisions. By uncovering the neural correlates of distinct stimulus encoding and evidence accumulation processes, this study delineated, for the first time, the functional role of cortical areas in active tactile decision-making. Copyright © 2018 Elsevier Inc. All rights reserved.

Can Tactile Sensory Processing Differentiate Between Children with Autistic Disorder and Asperger's Disorder?

PubMed Central

2011-01-01

Objective There are debates whether autistic disorder (autism) and Asperger's disorder are two distinct disorders. Moreover, interventional sensory occupational therapy should consider the clinical characteristics of patients. Already, commonalities and differences between Asperger's disorder and autistic disorder are not well studied. The aim of this study is to compare tactile sensory function of children with autistic disorder and children with Asperger's disorder. Methods Tactile sensory function was compared between 36 children with autism and 19 children with Asperger's disorder. The two disorders were diagnosed based on Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision. The parent-reported Tactile Dysfunction Checklist was used to assess the three aspects of hypersensitivity, hyposensitivity, and poor tactile perception and discrimination. Developmental coordination was also assessed. Results Developmental coordination problems total score was not associated with group. The mean (standard deviation) score of tactile hyper-responsivity was not different between the groups. Tactile hyporesponsivity and poor tactile perception and discrimination scores were statistically higher in autistic disorder than Asperger's disorder group. Conclusion These results for the first time indicated that at least some aspects of tactile perception can differentiate these two disorders. Children with autistic disorder have more tactile sensory seeking behaviors than children with Asperger's disorder. Moreover, the ability of children with autistic disorder for tactile discrimination and sensory perception is less than those with Asperger's disorder. Interventional sensory therapy in children with autistic disorder should have some characteristics that can be different and specific for children with Asperger's disorder. Formal intelligence quotient testing was not performed on all of the children evaluated, which is a limitation to this study. In

Characterization and optimization of flexible dual mode sensor based on Carbon Micro Coils

NASA Astrophysics Data System (ADS)

Dat Nguyen, Tien; Kim, Taeseung; Han, Hyoseung; Shin, Hyun Yeong; Nguyen, Canh Toan; Phung, Hoa; Ryeol Choi, Hyouk

2018-01-01

Carbon Microcoils (CMCs) is a 3D helical micro structure grown via a chemical vapor deposition process. It is noted that composites in which CMCs are embedded in polymer matrixes, called CMC sheets, experience a drastic change of electrical impedance depending on the proximity and contact of external objects. In this paper, a dual functional sensor, that is, tactile and proximity sensor fabricated with CMC/silicone composite is presented to demonstrate the advanced characteristics of CMCs sheets. Characteristics of sensor responses depending on CMC compositions are investigated and optimal conditions are determined. The candidates of polymer matrices are also investigated. As the results, the CMC sheet consisting of Ecoflex 30, CMC 30 {{wt}} % , and multiwall carbon nanotubes 1 {{wt}} % shows the most appropriate tactile sensing characteristics with more than 1 mm of thickness. The proximity sensing capability is the maximum when the 1.5 {{wt}} % CMC content is mixed with Dragon skin 30 silicone substrate. Finally, multiple target objects are recognized with the results and their feasibilities are experimentally validated.

Encoding of Tactile Stimuli by Mechanoreceptors and Interneurons of the Medicinal Leech

PubMed Central

Kretzberg, Jutta; Pirschel, Friederice; Fathiazar, Elham; Hilgen, Gerrit

2016-01-01

For many animals processing of tactile information is a crucial task in behavioral contexts like exploration, foraging, and stimulus avoidance. The leech, having infrequent access to food, developed an energy efficient reaction to tactile stimuli, avoiding unnecessary muscle movements: The local bend behavior moves only a small part of the body wall away from an object touching the skin, while the rest of the animal remains stationary. Amazingly, the precision of this localized behavioral response is similar to the spatial discrimination threshold of the human fingertip, although the leech skin is innervated by an order of magnitude fewer mechanoreceptors and each midbody ganglion contains only 400 individually identified neurons in total. Prior studies suggested that this behavior is controlled by a three-layered feed-forward network, consisting of four mechanoreceptors (P cells), approximately 20 interneurons and 10 individually characterized motor neurons, all of which encode tactile stimulus location by overlapping, symmetrical tuning curves. Additionally, encoding of mechanical force was attributed to three types of mechanoreceptors reacting to distinct intensity ranges: T cells for touch, P cells for pressure, and N cells for strong, noxious skin stimulation. In this study, we provide evidences that tactile stimulus encoding in the leech is more complex than previously thought. Combined electrophysiological, anatomical, and voltage sensitive dye approaches indicate that P and T cells both play a major role in tactile information processing resulting in local bending. Our results indicate that tactile encoding neither relies on distinct force intensity ranges of different cell types, nor location encoding is restricted to spike count tuning. Instead, we propose that P and T cells form a mixed type population, which simultaneously employs temporal response features and spike counts for multiplexed encoding of touch location and force intensity. This hypothesis

Tactile Functioning in Children Who Are Blind: A Clinical Perspective

ERIC Educational Resources Information Center

Withagen, Ans; Vervloed, Mathijs P. J.; Janssen, Neeltje M.; Knoors, Harry; Verhoeven, Ludo

2010-01-01

This study of 48 children with congenital blindness who attended mainstream schools focused on the tactile and haptic skills they needed in typical academic and everyday tasks. The results showed that, in general, the children mastered such tactile tasks, but some items posed special problems. (Contains 4 tables.)

Development of compact slip detection sensor using dielectric elastomer

NASA Astrophysics Data System (ADS)

Choi, Jae-young; Hwang, Do-Yeon; Kim, Baek-chul; Moon, Hyungpil; Choi, Hyouk Ryeol; Koo, Ja Choon

2015-04-01

In this paper, we developed a resistance tactile sensor that can detect a slip on the surface of sensor structure. The presented sensor device has fingerprint-like structures that are similar with the role of the humans finger print. The resistance slip sensor that the novel developed uses acrylo-nitrile butadiene rubber (NBR) as a dielectric substrate and graphene as an electrode material. We can measure the slip as the structure of sensor makes a deformation and it changes the resistance through forming a new conductive route. To manufacture our sensor, we developed a new imprint process. By using this process, we can produce sensor with micro unit structure. To verify effectiveness of the proposed slip detection, experiment using prototype of resistance slip sensor is conducted with an algorithm to detect slip and slip is successfully detected. We will discuss the slip detection properties.

Tactile-Foot Stimulation Can Assist the Navigation of People with Visual Impairment

PubMed Central

Velázquez, Ramiro; Pissaloux, Edwige; Lay-Ekuakille, Aimé

2015-01-01

Background. Tactile interfaces that stimulate the plantar surface with vibrations could represent a step forward toward the development of wearable, inconspicuous, unobtrusive, and inexpensive assistive devices for people with visual impairments. Objective. To study how people understand information through their feet and to maximize the capabilities of tactile-foot perception for assisting human navigation. Methods. Based on the physiology of the plantar surface, three prototypes of electronic tactile interfaces for the foot have been developed. With important technological improvements between them, all three prototypes essentially consist of a set of vibrating actuators embedded in a foam shoe-insole. Perceptual experiments involving direction recognition and real-time navigation in space were conducted with a total of 60 voluntary subjects. Results. The developed prototypes demonstrated that they are capable of transmitting tactile information that is easy and fast to understand. Average direction recognition rates were 76%, 88.3%, and 94.2% for subjects wearing the first, second, and third prototype, respectively. Exhibiting significant advances in tactile-foot stimulation, the third prototype was evaluated in navigation tasks. Results show that subjects were capable of following directional instructions useful for navigating spaces. Conclusion. Footwear providing tactile stimulation can be considered for assisting the navigation of people with visual impairments. PMID:27019593

Tactile-Foot Stimulation Can Assist the Navigation of People with Visual Impairment.

PubMed

Velázquez, Ramiro; Pissaloux, Edwige; Lay-Ekuakille, Aimé

2015-01-01

Background. Tactile interfaces that stimulate the plantar surface with vibrations could represent a step forward toward the development of wearable, inconspicuous, unobtrusive, and inexpensive assistive devices for people with visual impairments. Objective. To study how people understand information through their feet and to maximize the capabilities of tactile-foot perception for assisting human navigation. Methods. Based on the physiology of the plantar surface, three prototypes of electronic tactile interfaces for the foot have been developed. With important technological improvements between them, all three prototypes essentially consist of a set of vibrating actuators embedded in a foam shoe-insole. Perceptual experiments involving direction recognition and real-time navigation in space were conducted with a total of 60 voluntary subjects. Results. The developed prototypes demonstrated that they are capable of transmitting tactile information that is easy and fast to understand. Average direction recognition rates were 76%, 88.3%, and 94.2% for subjects wearing the first, second, and third prototype, respectively. Exhibiting significant advances in tactile-foot stimulation, the third prototype was evaluated in navigation tasks. Results show that subjects were capable of following directional instructions useful for navigating spaces. Conclusion. Footwear providing tactile stimulation can be considered for assisting the navigation of people with visual impairments.

Micromachined actuators/sensors for intratubular positioning/steering

DOEpatents

Lee, A.P.; Krulevitch, P.A.; Northrup, M.A.; Trevino, J.C.

1998-06-30

Micromachined thin film cantilever actuators having means for individually controlling the deflection of the cantilevers, valve members, and rudders for steering same through blood vessels, or positioning same within a blood vessel, for example. Such cantilever actuators include tactile sensor arrays mounted on a catheter or guide wire tip for navigation and tissues identification, shape-memory alloy film based catheter/guide wire steering mechanisms, and rudder-based steering devices that allow the selective actuation of rudders that use the flowing blood itself to help direct the catheter direction through the blood vessel. While particularly adapted for medical applications, these cantilever actuators can be used for steering through piping and tubing systems. 14 figs.

A Haptic Glove as a Tactile-Vision Sensory Substitution for Wayfinding.

ERIC Educational Resources Information Center

Zelek, John S.; Bromley, Sam; Asmar, Daniel; Thompson, David

2003-01-01

A device that relays navigational information using a portable tactile glove and a wearable computer and camera system was tested with nine adults with visual impairments. Paths traversed by subjects negotiating an obstacle course were not qualitatively different from paths produced with existing wayfinding devices and hitting probabilities were…

Development of Sic Gas Sensor Systems

NASA Technical Reports Server (NTRS)

Hunter, G. W.; Neudeck, P. G.; Okojie, R. S.; Beheim, G. M.; Thomas, V.; Chen, L.; Lukco, D.; Liu, C. C.; Ward, B.; Makel, D.

2002-01-01

Silicon carbide (SiC) based gas sensors have significant potential to address the gas sensing needs of aerospace applications such as emission monitoring, fuel leak detection, and fire detection. However, in order to reach that potential, a range of technical challenges must be overcome. These challenges go beyond the development of the basic sensor itself and include the need for viable enabling technologies to make a complete gas sensor system: electrical contacts, packaging, and transfer of information from the sensor to the outside world. This paper reviews the status at NASA Glenn Research Center of SiC Schottky diode gas sensor development as well as that of enabling technologies supporting SiC gas sensor system implementation. A vision of a complete high temperature microfabricated SiC gas sensor system is proposed. In the long-term, it is believed that improvements in the SiC semiconductor material itself could have a dramatic effect on the performance of SiC gas sensor systems.

An eight-legged tactile sensor to estimate coefficient of static friction.

PubMed

Wei Chen; Rodpongpun, Sura; Luo, William; Isaacson, Nathan; Kark, Lauren; Khamis, Heba; Redmond, Stephen J

2015-08-01

It is well known that a tangential force larger than the maximum static friction force is required to initiate the sliding motion between two objects, which is governed by a material constant called the coefficient of static friction. Therefore, knowing the coefficient of static friction is of great importance for robot grippers which wish to maintain a stable and precise grip on an object during various manipulation tasks. Importantly, it is most useful if grippers can estimate the coefficient of static friction without having to explicitly explore the object first, such as lifting the object and reducing the grip force until it slips. A novel eight-legged sensor, based on simplified theoretical principles of friction is presented here to estimate the coefficient of static friction between a planar surface and the prototype sensor. Each of the sensor's eight legs are straight and rigid, and oriented at a specified angle with respect to the vertical, allowing it to estimate one of five ranges (5 = 8/2 + 1) that the coefficient of static friction can occupy. The coefficient of friction can be estimated by determining whether the legs have slipped or not when pressed against a surface. The coefficients of static friction between the sensor and five different materials were estimated and compared to a measurement from traditional methods. A least-squares linear fit of the sensor estimated coefficient showed good correlation with the reference coefficient with a gradient close to one and an r(2) value greater than 0.9.

Intuitive tactile zooming for graphics accessed by individuals who are blind and visually impaired.

PubMed

Rastogi, Ravi; Pawluk, T V Dianne; Ketchum, Jessica

2013-07-01

One possibility of providing access to visual graphics for those who are visually impaired is to present them tactually: unfortunately, details easily available to vision need to be magnified to be accessible through touch. For this, we propose an "intuitive" zooming algorithm to solve potential problems with directly applying visual zooming techniques to haptic displays that sense the current location of a user on a virtual diagram with a position sensor and, then, provide the appropriate local information either through force or tactile feedback. Our technique works by determining and then traversing the levels of an object tree hierarchy of a diagram. In this manner, the zoom steps adjust to the content to be viewed, avoid clipping and do not zoom when no object is present. The algorithm was tested using a small, "mouse-like" display with tactile feedback on pictures representing houses in a community and boats on a lake. We asked the users to answer questions related to details in the pictures. Comparing our technique to linear and logarithmic step zooming, we found a significant increase in the correctness of the responses (odds ratios of 2.64:1 and 2.31:1, respectively) and usability (differences of 36% and 19%, respectively) using our "intuitive" zooming technique.

Tactile Imaging Markers to Characterize Female Pelvic Floor Conditions.

PubMed

van Raalte, Heather; Egorov, Vladimir

2015-08-01

The Vaginal Tactile Imager (VTI) records pressure patterns from vaginal walls under an applied tissue deformation and during pelvic floor muscle contractions. The objective of this study is to validate tactile imaging and muscle contraction parameters (markers) sensitive to the female pelvic floor conditions. Twenty-two women with normal and prolapse conditions were examined by a vaginal tactile imaging probe. We identified 9 parameters which were sensitive to prolapse conditions ( p < 0.05 for one-way ANOVA and/or p < 0.05 for t -test with correlation factor r from -0.73 to -0.56). The list of parameters includes pressure, pressure gradient and dynamic pressure response during muscle contraction at identified locations. These parameters may be used for biomechanical characterization of female pelvic floor conditions to support an effective management of pelvic floor prolapse.

Smart Sensor Systems for Aerospace Applications: From Sensor Development to Application Testing

NASA Technical Reports Server (NTRS)

Hunter, G. W.; Xu, J. C.; Dungan, L. K.; Ward, B. J.; Rowe, S.; Williams, J.; Makel, D. B.; Liu, C. C.; Chang, C. W.

2008-01-01

The application of Smart Sensor Systems for aerospace applications is a multidisciplinary process consisting of sensor element development, element integration into Smart Sensor hardware, and testing of the resulting sensor systems in application environments. This paper provides a cross-section of these activities for multiple aerospace applications illustrating the technology challenges involved. The development and application testing topics discussed are: 1) The broadening of sensitivity and operational range of silicon carbide (SiC) Schottky gas sensor elements; 2) Integration of fire detection sensor technology into a "Lick and Stick" Smart Sensor hardware platform for Crew Exploration Vehicle applications; 3) Extended testing for zirconia based oxygen sensors in the basic "Lick and Stick" platform for environmental monitoring applications. It is concluded that that both core sensor platform technology and a basic hardware platform can enhance the viability of implementing smart sensor systems in aerospace applications.

Intelligent Sensors: An Integrated Systems Approach

NASA Technical Reports Server (NTRS)

Mahajan, Ajay; Chitikeshi, Sanjeevi; Bandhil, Pavan; Utterbach, Lucas; Figueroa, Fernando

2005-01-01

The need for intelligent sensors as a critical component for Integrated System Health Management (ISHM) is fairly well recognized by now. Even the definition of what constitutes an intelligent sensor (or smart sensor) is well documented and stems from an intuitive desire to get the best quality measurement data that forms the basis of any complex health monitoring and/or management system. If the sensors, i.e. the elements closest to the measurand, are unreliable then the whole system works with a tremendous handicap. Hence, there has always been a desire to distribute intelligence down to the sensor level, and give it the ability to assess its own health thereby improving the confidence in the quality of the data at all times. This paper proposes the development of intelligent sensors as an integrated systems approach, i.e. one treats the sensors as a complete system with its own sensing hardware (the traditional sensor), A/D converters, processing and storage capabilities, software drivers, self-assessment algorithms, communication protocols and evolutionary methodologies that allow them to get better with time. Under a project being undertaken at the NASA Stennis Space Center, an integrated framework is being developed for the intelligent monitoring of smart elements. These smart elements can be sensors, actuators or other devices. The immediate application is the monitoring of the rocket test stands, but the technology should be generally applicable to the Intelligent Systems Health Monitoring (ISHM) vision. This paper outlines some fundamental issues in the development of intelligent sensors under the following two categories: Physical Intelligent Sensors (PIS) and Virtual Intelligent Sensors (VIS).

Effects of inter-stimulus interval and intensity on the perceived urgency of tactile patterns.

PubMed

White, Timothy L; Krausman, Andrea S

2015-05-01

This research examines the feasibility of coding urgency into tactile patterns. Four tactile patterns were presented at either, 12 or 23.5 dB above mean threshold, with an ISI of either 0 (no interval) or 500 msec. Measures included pattern identification and urgency rating on a scale of 1 (least urgent) to 10 (most urgent). Two studies were conducted, a laboratory study and a field study. In the laboratory study, participants received the tactile patterns while seated in front of a computer. For the field study, participants performed dismounted Soldier maneuvers while receiving the tactile patterns. Higher identification rates were found for the 23.5 dB intensity. Patterns presented at the 23.5 dB intensity and no ISI were rated most urgent. No differences in urgency ratings were found for 12 dB based on ISI. Findings support the notion of coding urgency into tactile patterns as a way of augmenting tactile communication. Published by Elsevier Ltd.

Distributed sensor coordination for advanced energy systems

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

Tumer, Kagan

Motivation: The ability to collect key system level information is critical to the safe, efficient and reliable operation of advanced power systems. Recent advances in sensor technology have enabled some level of decision making directly at the sensor level. However, coordinating large numbers of sensors, particularly heterogeneous sensors, to achieve system level objectives such as predicting plant efficiency, reducing downtime or predicting outages requires sophisticated coordination algorithms. Indeed, a critical issue in such systems is how to ensure the interaction of a large number of heterogenous system components do not interfere with one another and lead to undesirable behavior. Objectivesmore » and Contributions: The long-term objective of this work is to provide sensor deployment, coordination and networking algorithms for large numbers of sensors to ensure the safe, reliable, and robust operation of advanced energy systems. Our two specific objectives are to: 1. Derive sensor performance metrics for heterogeneous sensor networks. 2. Demonstrate effectiveness, scalability and reconfigurability of heterogeneous sensor network in advanced power systems. The key technical contribution of this work is to push the coordination step to the design of the objective functions of the sensors, allowing networks of heterogeneous sensors to be controlled. By ensuring that the control and coordination is not specific to particular sensor hardware, this approach enables the design and operation of large heterogeneous sensor networks. In addition to the coordination coordination mechanism, this approach allows the system to be reconfigured in response to changing needs (e.g., sudden external events requiring new responses) or changing sensor network characteristics (e.g., sudden changes to plant condition). Impact: The impact of this work extends to a large class of problems relevant to the National Energy Technology Laboratory including sensor placement

Functional consequences of experience-dependent plasticity on tactile perception following perceptual learning.

PubMed

Trzcinski, Natalie K; Gomez-Ramirez, Manuel; Hsiao, Steven S

2016-09-01

Continuous training enhances perceptual discrimination and promotes neural changes in areas encoding the experienced stimuli. This type of experience-dependent plasticity has been demonstrated in several sensory and motor systems. Particularly, non-human primates trained to detect consecutive tactile bar indentations across multiple digits showed expanded excitatory receptive fields (RFs) in somatosensory cortex. However, the perceptual implications of these anatomical changes remain undetermined. Here, we trained human participants for 9 days on a tactile task that promoted expansion of multi-digit RFs. Participants were required to detect consecutive indentations of bar stimuli spanning multiple digits. Throughout the training regime we tracked participants' discrimination thresholds on spatial (grating orientation) and temporal tasks on the trained and untrained hands in separate sessions. We hypothesized that training on the multi-digit task would decrease perceptual thresholds on tasks that require stimulus processing across multiple digits, while also increasing thresholds on tasks requiring discrimination on single digits. We observed an increase in orientation thresholds on a single digit. Importantly, this effect was selective for the stimulus orientation and hand used during multi-digit training. We also found that temporal acuity between digits improved across trained digits, suggesting that discriminating the temporal order of multi-digit stimuli can transfer to temporal discrimination of other tactile stimuli. These results suggest that experience-dependent plasticity following perceptual learning improves and interferes with tactile abilities in manners predictive of the task and stimulus features used during training. © 2016 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

Active Prior Tactile Knowledge Transfer for Learning Tactual Properties of New Objects

PubMed Central

Feng, Di

2018-01-01

Reusing the tactile knowledge of some previously-explored objects (prior objects) helps us to easily recognize the tactual properties of new objects. In this paper, we enable a robotic arm equipped with multi-modal artificial skin, like humans, to actively transfer the prior tactile exploratory action experiences when it learns the detailed physical properties of new objects. These experiences, or prior tactile knowledge, are built by the feature observations that the robot perceives from multiple sensory modalities, when it applies the pressing, sliding, and static contact movements on objects with different action parameters. We call our method Active Prior Tactile Knowledge Transfer (APTKT), and systematically evaluated its performance by several experiments. Results show that the robot improved the discrimination accuracy by around 10% when it used only one training sample with the feature observations of prior objects. By further incorporating the predictions from the observation models of prior objects as auxiliary features, our method improved the discrimination accuracy by over 20%. The results also show that the proposed method is robust against transferring irrelevant prior tactile knowledge (negative knowledge transfer). PMID:29466300

Salience of Tactile Cues: An Examination of Tactor Actuator and Tactile Cue Characteristics

DTIC Science & Technology

2015-08-01

this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense ...patterns of tactile cue arrays, and some differences due to measurement approach. Implications for future research are discussed. 15. SUBJECT TERMS...results for tactor type, taction, and interaction term for the prediction of forced-choice preference ................................................21

Behavioral Impact of Unisensory and Multisensory Audio-Tactile Events: Pros and Cons for Interlimb Coordination in Juggling

PubMed Central

Zelic, Gregory; Mottet, Denis; Lagarde, Julien

2012-01-01

Recent behavioral neuroscience research revealed that elementary reactive behavior can be improved in the case of cross-modal sensory interactions thanks to underlying multisensory integration mechanisms. Can this benefit be generalized to an ongoing coordination of movements under severe physical constraints? We choose a juggling task to examine this question. A central issue well-known in juggling lies in establishing and maintaining a specific temporal coordination among balls, hands, eyes and posture. Here, we tested whether providing additional timing information about the balls and hands motions by using external sound and tactile periodic stimulations, the later presented at the wrists, improved the behavior of jugglers. One specific combination of auditory and tactile metronome led to a decrease of the spatiotemporal variability of the juggler's performance: a simple sound associated to left and right tactile cues presented antiphase to each other, which corresponded to the temporal pattern of hands movement in the juggling task. A contrario, no improvements were obtained in the case of other auditory and tactile combinations. We even found a degraded performance when tactile events were presented alone. The nervous system thus appears able to integrate in efficient way environmental information brought by different sensory modalities, but only if the information specified matches specific features of the coordination pattern. We discuss the possible implications of these results for the understanding of the neuronal integration process implied in audio-tactile interaction in the context of complex voluntary movement, and considering the well-known gating effect of movement on vibrotactile perception. PMID:22384211

Surface texture can bias tactile form perception.

PubMed

Nakatani, Masashi; Howe, Robert D; Tachi, Susumu

2011-01-01

The sense of touch is believed to provide a reliable perception of the object's properties; however, our tactile perceptions could be illusory at times. A recently reported tactile illusion shows that a raised form can be perceived as indented when it is surrounded by textured areas. This phenomenon suggests that the form perception can be influenced by the surface textures in its adjacent areas. As perception of texture and that of form have been studied independently of each other, the present study examined whether textures, in addition to the geometric edges, contribute to the tactile form perception. We examined the perception of the flat and raised contact surface (3.0 mm width) with various heights (0.1, 0.2, 0.3 mm), which had either textured or non-textured adjacent areas, under the static, passive and active touch conditions. Our results showed that texture decreased the raised perception of the surface with a small height (0.1 mm) and decreased the flat perception of the physically flat surface under the passive and active touch conditions. We discuss a possible mechanism underlying the effect of the textures on the form perception based on previous neurophysiological findings.

The use of a tactile interface to convey position and motion perceptions

NASA Technical Reports Server (NTRS)

Rupert, A. H.; Guedry, F. E.; Reschke, M. F.

1994-01-01

Under normal terrestrial conditions, perception of position and motion is determined by central nervous system integration of concordant and redundant information from multiple sensory channels (somatosensory, vestibular, visual), which collectively yield vertical perceptions. In the acceleration environment experienced by the pilots, the somatosensory and vestibular sensors frequently present false information concerning the direction of gravity. When presented with conflicting sensory information, it is normal for pilots to experience episodes of disorientation. We have developed a tactile interface that obtains vertical roll and pitch information from a gyro-stabilized attitude indicator and maps this information in a one-to-one correspondence onto the torso of the body using a matrix of vibrotactors. This enables the pilot to continuously maintain an awareness of aircraft attitude without reference to visual cues, utilizing a sensory channel that normally operates at the subconscious level. Although initially developed to improve pilot spatial awareness, this device has obvious applications to 1) simulation and training, 2) nonvisual tracking of targets, which can reduce the need for pilots to make head movements in the high-G environment of aerial combat, and 3) orientation in environments with minimal somatosensory cues (e.g., underwater) or gravitational cues (e.g., space).

Bilateral Symmetry of Distortions of Tactile Size Perception.

PubMed

Longo, Matthew R; Ghosh, Arko; Yahya, Tasneem

2015-01-01

The perceived distance between touches on the limbs is generally bigger for distances oriented across the width of the limb than for distances oriented along the length of the limb. The present study aimed to investigate the coherence of such distortions of tactile size perception across different skin surfaces. We investigated distortions of tactile size perception on the dorsal and palmar surfaces of both the left and right hands as well as the forehead. Participants judged which of two tactile distances felt larger. One distance was aligned with the proximodistal axis (along the body), the other with the mediolateral axis (across the body). Clear distortions were found on all five skin surfaces, with stimuli oriented across the width of the body being perceived as farther apart than those oriented along the length of the body. Consistent with previous results, distortions were smaller on the palmar than on the dorsal hand surface. Distortion on the forehead was intermediate between the dorsal and palmar surfaces. There were clear correlations between distortion on the left and right hands, for both the dorsal and palmar skin surfaces. In contrast, within each hand, there was no significant correlation between the two skin surfaces. Distortion on the forehead was not significantly correlated with that on any of the other skin surfaces. These results provide evidence for bilaterally symmetric representations underlying tactile size perception. © The Author(s) 2015.

Effect of degree of crosslinking and polymerization of 3D printable polymer/ionic liquid composites on performance of stretchable piezoresistive sensors

NASA Astrophysics Data System (ADS)

Lee, Jeongwoo; Faruk Emon, Md Omar; Vatani, Morteza; Choi, Jae-Won

2017-03-01

Ionic liquid (IL)/polymer composites (1-ethyl-3-methyl-imidazolium tetrafluoroborate (EMIMBF4)/2-[[(butylamino)carbonyl]oxy]ethyl acrylate (BACOEA)) were fabricated to use as sensing materials for stretchable piezoresistive tactile sensors. The detectability of the IL/polymer composites was enhanced because the ionic transport properties of EMIMBF4 in the composites were improved by the synergic actions between the coordinate sites generated by the local motion of BACOEA chain segments under enough activation energy. The performance of the piezoresistive sensors was investigated with the degree of crosslinking and polymerization of the IL/polymer composites. As the compressive strain was increased, the distance between two electrodes decreased, and the motion of polymer chains and IL occurred, resulting in a decrease in the electrical resistance of the sensors. We have confirmed that the sensitivity of the sensors are affected by the degree of crosslink and polymerization of the IL/polymer composites. In addition, all of the materials (skins, sensing material, and electrode) used in this study are photo-curable, and thus the stretchable piezoresistive tactile sensors can be successfully fabricated by 3D printing.

Tactile Imaging Markers to Characterize Female Pelvic Floor Conditions

PubMed Central

van Raalte, Heather; Egorov, Vladimir

2015-01-01

The Vaginal Tactile Imager (VTI) records pressure patterns from vaginal walls under an applied tissue deformation and during pelvic floor muscle contractions. The objective of this study is to validate tactile imaging and muscle contraction parameters (markers) sensitive to the female pelvic floor conditions. Twenty-two women with normal and prolapse conditions were examined by a vaginal tactile imaging probe. We identified 9 parameters which were sensitive to prolapse conditions (p < 0.05 for one-way ANOVA and/or p < 0.05 for t-test with correlation factor r from −0.73 to −0.56). The list of parameters includes pressure, pressure gradient and dynamic pressure response during muscle contraction at identified locations. These parameters may be used for biomechanical characterization of female pelvic floor conditions to support an effective management of pelvic floor prolapse. PMID:26389014

Whole-arm tactile sensing for beneficial and acceptable contact during robotic assistance.

PubMed

Grice, Phillip M; Killpack, Marc D; Jain, Advait; Vaish, Sarvagya; Hawke, Jeffrey; Kemp, Charles C

2013-06-01

Many assistive tasks involve manipulation near the care-receiver's body, including self-care tasks such as dressing, feeding, and personal hygiene. A robot can provide assistance with these tasks by moving its end effector to poses near the care-receiver's body. However, perceiving and maneuvering around the care-receiver's body can be challenging due to a variety of issues, including convoluted geometry, compliant materials, body motion, hidden surfaces, and the object upon which the body is resting (e.g., a wheelchair or bed). Using geometric simulations, we first show that an assistive robot can achieve a much larger percentage of end-effector poses near the care-receiver's body if its arm is allowed to make contact. Second, we present a novel system with a custom controller and whole-arm tactile sensor array that enables a Willow Garage PR2 to regulate contact forces across its entire arm while moving its end effector to a commanded pose. We then describe tests with two people with motor impairments, one of whom used the system to grasp and pull a blanket over himself and to grab a cloth and wipe his face, all while in bed at his home. Finally, we describe a study with eight able-bodied users in which they used the system to place objects near their bodies. On average, users perceived the system to be safe and comfortable, even though substantial contact occurred between the robot's arm and the user's body.

Decline of human tactile angle discrimination in patients with mild cognitive impairment and Alzheimer's disease.

PubMed

Yang, Jiajia; Ogasa, Takashi; Ohta, Yasuyuki; Abe, Koji; Wu, Jinglong

2010-01-01

There is a need to differentiate between patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) from normal-aged controls (NC) in the field of clinical drug discovery. In this study, we developed a tactile angle discrimination system and examined whether the ability to discriminate tactile angle differed between patients with MCI and AD and the NC group. Thirty-seven subjects were divided into three groups: NC individuals (n=14); MCI patients (n=10); and probable AD patients (n=13). All subjects were asked to differentiate the relative sizes of the reference angle (60°) and one of eight comparison angles by passive touch. The accuracy of angle discrimination was measured and the discrimination threshold was calculated. We discovered that there were significant differences in the angle discrimination thresholds of AD patients compared to the NC group. Interestingly, we also found that ability to discriminate tactile angle of MCI patients were significantly lower than that of the NC group. This is the first study to report that patients with MCI and AD have substantial performance deficits in tactile angle discrimination compared to the NC individuals. This finding may provide a monitor and therapeutic approach in AD diagnosis and treatment.

An adenosine kinase inhibitor attenuates tactile allodynia in a rat model of diabetic neuropathic pain.

PubMed

Lynch, J J; Jarvis, M F; Kowaluk, E A

1999-01-08

The present study was conducted to characterize the development of tactile allodynia in the streptozotocin-induced rat model of diabetes, and to evaluate the antinociceptive effects of systemically administered morphine and the adenosine kinase inhibitor, 5'-deoxy-5-iodotubercidin (5'd-5IT) in this model. Rats were injected with 75 mg/kg streptozotocin (i.p.), and blood glucose levels were determined 3-4 weeks later. Diabetic (blood glucose levels > or = 250 mg/dl) and vehicle-injected rats were examined weekly for the development of tactile allodynia by measuring the threshold for hind paw withdrawal using von Frey hairs. Withdrawal thresholds were reduced to 6.8+/-0.6 g (mean+/-S.E.M.) in approximately one-third of streptozotocin-treated rats 7 weeks after streptozotocin treatment as compared to control thresholds (13.2+/-0.1 g), and this allodynia persisted for at least an additional 7 weeks. In additional experiments, morphine sulfate (5-21 micromol/kg, i.p.) produced dose-dependent antinociceptive effects on tactile allodynia for up to 2 h post-dosing. The adenosine kinase inhibitor, 5'd-5IT (2.5 and 5 micromol/kg, i.p.) also dose-dependently attenuated tactile allodynia. Pretreatment with the opioid receptor antagonist, naloxone (27 micromol/kg, i.p.) or the non-selective adenosine receptor antagonist, theophylline (111 micromol/kg, i.p.) significantly diminished the anti-allodynic effects of morphine and 5'd-5IT, respectively. The present study demonstrates that the potent and selective adenosine kinase inhibitor, 5'd-5IT, is equally effective as morphine in blocking tactile allodynia in this model.

Braille and Tactile Graphics: Youths with Visual Impairments Share Their Experiences

ERIC Educational Resources Information Center

Rosenblum, L. Penny; Herzberg, Tina S.

2015-01-01

Introduction: Data were collected from youths with visual impairment about their experiences with tactile graphics and braille materials used in mathematics and science classes. Methods: Youths answered questions and explored four tactile graphics made using different production methods. They located specific information on each graphic and shared…

Tactile stimulations and wheel rotation responses: toward augmented lane departure warning systems

PubMed Central

Tandonnet, Christophe; Burle, Borís; Vidal, Franck; Hasbroucq, Thierry

2014-01-01

When an on-board system detects a drift of a vehicle to the left or to the right, in what way should the information be delivered to the driver? Car manufacturers have so far neglected relevant results from Experimental Psychology and Cognitive Neuroscience. Here we show that this situation possibly led to the sub-optimal design of a lane departure warning system (AFIL, PSA Peugeot Citroën) implemented in commercially available automobile vehicles. Twenty participants performed a two-choice reaction time task in which they were to respond by clockwise or counter-clockwise wheel-rotations to tactile stimulations of their left or right wrist. They performed poorer when responding counter-clockwise to the right vibration and clockwise to the left vibration (incompatible mapping) than when responding according to the reverse (compatible) mapping. This suggests that AFIL implements the worse (incompatible) mapping for the operators. This effect depended on initial practice with the interface. The present research illustrates how basic approaches in Cognitive Science may benefit to Human Factors Engineering and ultimately improve man-machine interfaces and show how initial learning can affect interference effects. PMID:25324791

Natural Whisker-Guided Behavior by Head-Fixed Mice in Tactile Virtual Reality

PubMed Central

Sofroniew, Nicholas J.; Cohen, Jeremy D.; Lee, Albert K.

2014-01-01

During many natural behaviors the relevant sensory stimuli and motor outputs are difficult to quantify. Furthermore, the high dimensionality of the space of possible stimuli and movements compounds the problem of experimental control. Head fixation facilitates stimulus control and movement tracking, and can be combined with techniques for recording and manipulating neural activity. However, head-fixed mouse behaviors are typically trained through extensive instrumental conditioning. Here we present a whisker-based, tactile virtual reality system for head-fixed mice running on a spherical treadmill. Head-fixed mice displayed natural movements, including running and rhythmic whisking at 16 Hz. Whisking was centered on a set point that changed in concert with running so that more protracted whisking was correlated with faster running. During turning, whiskers moved in an asymmetric manner, with more retracted whisker positions in the turn direction and protracted whisker movements on the other side. Under some conditions, whisker movements were phase-coupled to strides. We simulated a virtual reality tactile corridor, consisting of two moveable walls controlled in a closed-loop by running speed and direction. Mice used their whiskers to track the walls of the winding corridor without training. Whisker curvature changes, which cause forces in the sensory follicles at the base of the whiskers, were tightly coupled to distance from the walls. Our behavioral system allows for precise control of sensorimotor variables during natural tactile navigation. PMID:25031397

Use of early tactile stimulation in rehabilitation of digital nerve injuries.

PubMed

Cheng, A S

2000-01-01

Digital nerves are the most frequently injured peripheral nerve. To improve the recovery of functional sensibility of digital nerve injuries, a prospective randomized controlled study was conducted to see the effect of using early tactile stimulation in rehabilitation of digital nerve injuries. Two specific tactile stimulators were made and prescribed for patients with digital nerve-injury. Twenty-four participants with 32 digital nerve injuries received the prescribed tactile stimulators (experimental group), and another 25 participants with 33 digital nerve injuries received only routine conventional therapy (control group). A significant difference (p < .05) was seen in the experimental group, although there were some variations between the different classes of associated injuries, with least benefit observed in the combined nerve, tendon, and bone injury class. Use of early tactile stimulation as described in this study can be considered an effective way to improve both quality and quantity of recovery of functional sensibility in digital nerve injuries without combined nerve, tendon, and bone injuries.

Fluidic Sensor Temperature Indicating System.

DTIC Science & Technology

A fluidic sensor temperature indicating system designed by Honeywell Inc was tested on a T56 engine during dynamometer calibration. It was also...based on the sensor being mounted in a T56 engine showed a hot gas temperature drop from 1970F at the sensor entrance to 1760F in the sensor pulsation

Tactile agnosia. Casuistic evidence and theoretical remarks on modality-specific meaning representations and sensorimotor integration.

PubMed

Platz, T

1996-10-01

Somaesthetic, motor and cognitive functions were studied in a man with impaired tactile object-recognition (TOR) in his left hand due to a right parietal convexity meningeoma which had been surgically removed. Primary motor and somatosensory functions were not impaired, and discriminative abilities for various tactile aspects and cognitive skills were preserved. Nevertheless, the patient could often not appreciate the object's nature or significance when it was placed in his left hand and was unable to name or to describe or demonstrate the use of these objects. Therefore, he can be regarded as an example of associative tactile agnosia. The view is taken and elaborated that defective modality-specific meaning representations account for associative tactile agnosia. These meaning representations are conceptualized as learned unimodal feature-entity relationships which are thought to be defective in tactile agnosia. In line with this hypothesis, tactile feature analysis and cross-modal matching of features were largely preserved in the investigated patient, while combining features to form entities was defective in the tactile domain. The alternative hypothesis of agnosia as deficit of cross-modal association of features was not supported. The presumed distributed functional network responsible for TOR is thought to involve perception of features, object recognition and related tactile motor behaviour interactively. A deficit leading primarily to impaired combining features to form entities can therefore be expected to result in additional minor impairment of related perceptual-motor processes. Unilaterality of the gnostic deficit can be explained by a lateralized organization of the functional network responsible for tactile recognition of objects.

Visual enhancing of tactile perception in the posterior parietal cortex.

PubMed

Ro, Tony; Wallace, Ruth; Hagedorn, Judith; Farnè, Alessandro; Pienkos, Elizabeth

2004-01-01

The visual modality typically dominates over our other senses. Here we show that after inducing an extreme conflict in the left hand between vision of touch (present) and the feeling of touch (absent), sensitivity to touch increases for several minutes after the conflict. Transcranial magnetic stimulation of the posterior parietal cortex after this conflict not only eliminated the enduring visual enhancement of touch, but also impaired normal tactile perception. This latter finding demonstrates a direct role of the parietal lobe in modulating tactile perception as a result of the conflict between these senses. These results provide evidence for visual-to-tactile perceptual modulation and demonstrate effects of illusory vision of touch on touch perception through a long-lasting modulatory process in the posterior parietal cortex.

High pressure fiber optic sensor system

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

Guida, Renato; Xia, Hua; Lee, Boon K

2013-11-26

The present application provides a fiber optic sensor system. The fiber optic sensor system may include a small diameter bellows, a large diameter bellows, and a fiber optic pressure sensor attached to the small diameter bellows. Contraction of the large diameter bellows under an applied pressure may cause the small diameter bellows to expand such that the fiber optic pressure sensor may measure the applied pressure.

Integration of tactile input across fingers in a patient with finger agnosia.

PubMed

Anema, Helen A; Overvliet, Krista E; Smeets, Jeroen B J; Brenner, Eli; Dijkerman, H Chris

2011-01-01

Finger agnosia has been described as an inability to explicitly individuate between the fingers, which is possibly due to fused neural representations of these fingers. Hence, are patients with finger agnosia unable to keep tactile information perceived over several fingers separate? Here, we tested a finger agnosic patient (GO) on two tasks that measured the ability to keep tactile information simultaneously perceived by individual fingers separate. In experiment 1 GO performed a haptic search task, in which a target (the absence of a protruded line) needed to be identified among distracters (protruded lines). The lines were presented simultaneously to the fingertips of both hands. Similarly to the controls, her reaction time decreased when her fingers were aligned as compared to when her fingers were stretched and in an unaligned position. This suggests that she can keep tactile input from different fingers separate. In experiment two, GO was required to judge the position of a target tactile stimulus to the index finger, relatively to a reference tactile stimulus to the middle finger, both in fingers uncrossed and crossed position. GO was able to indicate the relative position of the target stimulus as well as healthy controls, which indicates that she was able to keep tactile information perceived by two neighbouring fingers separate. Interestingly, GO performed better as compared to the healthy controls in the finger crossed condition. Together, these results suggest the GO is able to implicitly distinguish between tactile information perceived by multiple fingers. We therefore conclude that finger agnosia is not caused by minor disruptions of low-level somatosensory processing. These findings further underpin the idea of a selective impaired higher order body representation restricted to the fingers as underlying cause of finger agnosia. Copyright © 2010 Elsevier Ltd. All rights reserved.

Secured network sensor-based defense system

NASA Astrophysics Data System (ADS)

Wei, Sixiao; Shen, Dan; Ge, Linqiang; Yu, Wei; Blasch, Erik P.; Pham, Khanh D.; Chen, Genshe

2015-05-01

Network sensor-based defense (NSD) systems have been widely used to defend against cyber threats. Nonetheless, if the adversary finds ways to identify the location of monitor sensors, the effectiveness of NSD systems can be reduced. In this paper, we propose both temporal and spatial perturbation based defense mechanisms to secure NSD systems and make the monitor sensor invisible to the adversary. The temporal-perturbation based defense manipulates the timing information of published data so that the probability of successfully recognizing monitor sensors can be reduced. The spatial-perturbation based defense dynamically redeploys monitor sensors in the network so that the adversary cannot obtain the complete information to recognize all of the monitor sensors. We carried out experiments using real-world traffic traces to evaluate the effectiveness of our proposed defense mechanisms. Our data shows that our proposed defense mechanisms can reduce the attack accuracy of recognizing detection sensors.

Tactile sensitivity of gloved hands in the cold operation.

PubMed

Geng, Q; Kuklane, K; Holmér, I

1997-11-01

In this study, tactile sensitivity of gloved hand in the cold operation has been investigated. The relations among physical properties of protective gloves and hand tactile sensitivity and cold protection were also analysed both objectively and subjectively. Subjects with various gloves participated in the experimental study during cold exposure at different ambient temperatures of -12 degrees C and -25 degrees C. Tactual performance was measured using an identification task with various sizes of objects over the percentage of misjudgment. Forearm, hand and finger skin temperatures were also recorded throughout. The experimental data were analysed using analysis of variance (ANOVA) model and the Tukey's multiple range test. The results obtained indicated that the tactual performance was affected both by gloves and by hands/fingers cooling. Effect of object size on the tactile discrimination was significant and the misjudgment increased when similar sizes of objects were identified, especially at -25 degrees C.

Evaluation of accelerometer based multi-sensor versus single-sensor activity recognition systems.

PubMed

Gao, Lei; Bourke, A K; Nelson, John

2014-06-01

Physical activity has a positive impact on people's well-being and it had been shown to decrease the occurrence of chronic diseases in the older adult population. To date, a substantial amount of research studies exist, which focus on activity recognition using inertial sensors. Many of these studies adopt a single sensor approach and focus on proposing novel features combined with complex classifiers to improve the overall recognition accuracy. In addition, the implementation of the advanced feature extraction algorithms and the complex classifiers exceed the computing ability of most current wearable sensor platforms. This paper proposes a method to adopt multiple sensors on distributed body locations to overcome this problem. The objective of the proposed system is to achieve higher recognition accuracy with "light-weight" signal processing algorithms, which run on a distributed computing based sensor system comprised of computationally efficient nodes. For analysing and evaluating the multi-sensor system, eight subjects were recruited to perform eight normal scripted activities in different life scenarios, each repeated three times. Thus a total of 192 activities were recorded resulting in 864 separate annotated activity states. The methods for designing such a multi-sensor system required consideration of the following: signal pre-processing algorithms, sampling rate, feature selection and classifier selection. Each has been investigated and the most appropriate approach is selected to achieve a trade-off between recognition accuracy and computing execution time. A comparison of six different systems, which employ single or multiple sensors, is presented. The experimental results illustrate that the proposed multi-sensor system can achieve an overall recognition accuracy of 96.4% by adopting the mean and variance features, using the Decision Tree classifier. The results demonstrate that elaborate classifiers and feature sets are not required to achieve high

Tactile perceptual learning: learning curves and transfer to the contralateral finger.

PubMed

Kaas, Amanda L; van de Ven, Vincent; Reithler, Joel; Goebel, Rainer

2013-02-01

Tactile perceptual learning has been shown to improve performance on tactile tasks, but there is no agreement about the extent of transfer to untrained skin locations. The lack of such transfer is often seen as a behavioral index of the contribution of early somatosensory brain regions. Moreover, the time course of improvements has never been described explicitly. Sixteen subjects were trained on the Ludvigh task (a tactile vernier task) on four subsequent days. On the fifth day, transfer of learning to the non-trained contralateral hand was tested. In five subjects, we explored to what extent training effects were retained approximately 1.5 years after the final training session, expecting to find long-term retention of learning effects after training. Results showed that tactile perceptual learning mainly occurred offline, between sessions. Training effects did not transfer initially, but became fully available to the untrained contralateral hand after a few additional training runs. After 1.5 years, training effects were not fully washed out and could be recuperated within a single training session. Interpreted in the light of theories of visual perceptual learning, these results suggest that tactile perceptual learning is not fundamentally different from visual perceptual learning, but might proceed at a slower pace due to procedural and task differences, thus explaining the apparent divergence in the amount of transfer and long-term retention.

Fiber optic plantar pressure/shear sensor

NASA Astrophysics Data System (ADS)

Soetanto, William; Nguyen, Ngoc T.; Wang, Wei-Chih

2011-04-01

A full-scale foot pressure/shear sensor that has been developed to help diagnose the cause of ulcer formation in diabetic patients is presented. The design involves a tactile sensor array using intersecting optical fibers embedded in soft elastomer. The basic configuration incorporates a mesh that is comprised of two sets of parallel optical fiber plane; the planes are configured so the parallel rows of fiber of the top and bottom planes are perpendicular to each other. Threedimensional information is determined by measuring the loss of light from each of the waveguide to map the overall pressure distribution and the shifting of the layers relative to each other. In this paper we will present the latest development on the fiber optic plantar pressure/shear sensor which can measure normal force up from 19.09 kPa to 1000 kPa.

POF-IMU sensor system: A fusion between inertial measurement units and POF sensors for low-cost and highly reliable systems

NASA Astrophysics Data System (ADS)

Leal-Junior, Arnaldo G.; Vargas-Valencia, Laura; dos Santos, Wilian M.; Schneider, Felipe B. A.; Siqueira, Adriano A. G.; Pontes, Maria José; Frizera, Anselmo

2018-07-01

This paper presents a low cost and highly reliable system for angle measurement based on a sensor fusion between inertial and fiber optic sensors. The system consists of the sensor fusion through Kalman filter of two inertial measurement units (IMUs) and an intensity variation-based polymer optical fiber (POF) curvature sensor. In addition, the IMU was applied as a reference for a compensation technique of POF curvature sensor hysteresis. The proposed system was applied on the knee angle measurement of a lower limb exoskeleton in flexion/extension cycles and in gait analysis. Results show the accuracy of the system, where the Root Mean Square Error (RMSE) between the POF-IMU sensor system and the encoder was below 4° in the worst case and about 1° in the best case. Then, the POF-IMU sensor system was evaluated as a wearable sensor for knee joint angle assessment without the exoskeleton, where its suitability for this purpose was demonstrated. The results obtained in this paper pave the way for future applications of sensor fusion between electronic and fiber optic sensors in movement analysis.

The tactile movement aftereffect.

PubMed

Hollins, M; Favorov, O

1994-01-01

The existence of a tactile movement aftereffect was established in a series of experiments on the palmar surface of the hand and fingers of psychophysical observers. During adaptation, observers cupped their hand around a moving drum for up to 3 min; following this period of stimulation, they typically reported an aftereffect consisting of movement sensations located on and deep to the skin, and lasting for up to 1 min. Preliminary experiments comparing a number of stimulus materials mounted on the drum demonstrated that a surface approximating a low-spatial-frequency square wave, with a smooth microtexture, was especially effective at inducing the aftereffect; this adapting stimulus was therefore used throughout the two main experiments. In Experiment 1, the vividness of the aftereffect produced by 2 min of adaptation was determined under three test conditions: with the hand (1) remaining on the now stationary drum; (2) in contact with a soft, textured surface; or (3) suspended in air. Subjects' free magnitude estimates of the peak vividness of the aftereffect were not significantly different across conditions; each subject experienced the aftereffect at least once under each condition. Thus the tactile movement aftereffect does not seem to depend critically on the ponditions of stimulation that obtain while it is being experienced. In Experiment 2, the vividness and duration of the aftereffect were measured as a function of the duration of the adapting stimulus. Both measures increased steadily over the range of durations explored (30-180 sec). In its dependence on adapting duration, the aftereffect resembles the waterfall illusion in vision. An explanation for the tactile movement aftereffect is proposed, based on the model of cortical dynamics of Whitsel et al. (1989, 1991). With assumed modest variation of one parameter across individuals, this application of the model is able to account both for the data of the majority of subjects, who experienced the

Tactile interactions activate mirror system regions in the human brain.

PubMed

McKyton, Ayelet

2011-12-07

Communicating with others is essential for the development of a society. Although types of communications, such as language and visual gestures, were thoroughly investigated in the past, little research has been done to investigate interactions through touch. To study this we used functional magnetic resonance imaging. Twelve participants were scanned with their eyes covered while stroking four kinds of items, representing different somatosensory stimuli: a human hand, a realistic rubber hand, an object, and a simple texture. Although the human and the rubber hands had the same overall shape, in three regions there was significantly more blood oxygen level dependent activation when touching the real hand: the anterior medial prefrontal cortex, the ventral premotor cortex, and the posterior superior temporal cortex. The last two regions are part of the mirror network and are known to be activated through visual interactions such as gestures. Interestingly, in this study, these areas were activated through a somatosensory interaction. A control experiment was performed to eliminate confounds of temperature, texture, and imagery, suggesting that the activation in these areas was correlated with the touch of a human hand. These results reveal the neuronal network working behind human tactile interactions, and highlight the participation of the mirror system in such functions.

Pure Amorphagnosia without Tactile Object Agnosia.

PubMed

Kubota, Shinichirou; Yamada, Mai; Satoh, Hideyo; Satoh, Akira; Tsujihata, Mitsuhiro

2017-01-01

A 54-year-old female showed amorphagnosia without ahylognosia and tactile agnosia 40 days after the onset of right cerebral infarction. Her basic somatosensory functions were normal. The appreciation of substance qualities (hylognosia) was preserved, but the patient's inability to recognize the size and shape (morphagnosia) was confined to 2- and 3-dimensional shapes (amorphagnosia) in the left hand. However, the patient's ability to recognize real daily objects was well preserved. Brain MRI after admission showed ischemic lesions confined to the right pre- and postcentral gyri and the medial frontal cortex on DWI and FLAIR images. An analysis of SPECT images revealed that the most decreased areas were localized to the pre- and postcentral gyri, superior and inferior parietal lobules, supramarginal gyrus, and angular gyrus. Considering the previous reported cases, the responsible lesion for the impaired perception of hylognosia and morphagnosia may not necessarily be confined to the right hemisphere. To date, 5 reports (6 cases) of tactile agnosia have been published; 4 cases presented with both ahylognosia and amorphagnosia, while 1 presented with only amorphagnosia, and another showed amorphagnosia and mild ahylognosia. Our case is the first to present with only amorphagnosia without tactile agnosia. The mechanism for the well-preserved recognition of real objects may depend on the preserved hylognosia. Of note, there have been no reports showing only ahylognosia without amorphagnosia. Further studies are necessary to clarify whether or not patients with preserved hylognosia or morphagnosia retain the ability to perceive real objects.

Generalization of a tactile stimulus in horses.

PubMed Central

Dougherty, D M; Lewis, P

1993-01-01

Using horses, we investigated the control of operant behavior by a tactile stimulus (the training stimulus) and the generalization of behavior to six other similar test stimuli. In a stall, the experimenters mounted a response panel in the doorway. Located on this panel were a response lever and a grain dispenser. The experimenters secured a tactile-stimulus belt to the horse's back. The stimulus belt was constructed by mounting seven solenoids along a piece of burlap in a manner that allowed each to provide the delivery of a tactile stimulus, a repetitive light tapping, at different locations (spaced 10.0 cm apart) along the horse's back. Two preliminary steps were necessary before generalization testing: training a measurable response (lip pressing) and training on several reinforcement schedules in the presence of a training stimulus (tapping by one of the solenoids). We then gave each horse two generalization test sessions. Results indicated that the horses' behavior was effectively controlled by the training stimulus. Horses made the greatest number of responses to the training stimulus, and the tendency to respond to the other test stimuli diminished as the stimuli became farther away from the training stimulus. These findings are discussed in the context of behavioral principles and their relevance to the training of horses. PMID:8315368

Generalization of a tactile stimulus in horses.

PubMed

Dougherty, D M; Lewis, P

1993-05-01

Using horses, we investigated the control of operant behavior by a tactile stimulus (the training stimulus) and the generalization of behavior to six other similar test stimuli. In a stall, the experimenters mounted a response panel in the doorway. Located on this panel were a response lever and a grain dispenser. The experimenters secured a tactile-stimulus belt to the horse's back. The stimulus belt was constructed by mounting seven solenoids along a piece of burlap in a manner that allowed each to provide the delivery of a tactile stimulus, a repetitive light tapping, at different locations (spaced 10.0 cm apart) along the horse's back. Two preliminary steps were necessary before generalization testing: training a measurable response (lip pressing) and training on several reinforcement schedules in the presence of a training stimulus (tapping by one of the solenoids). We then gave each horse two generalization test sessions. Results indicated that the horses' behavior was effectively controlled by the training stimulus. Horses made the greatest number of responses to the training stimulus, and the tendency to respond to the other test stimuli diminished as the stimuli became farther away from the training stimulus. These findings are discussed in the context of behavioral principles and their relevance to the training of horses.

Sensor Systems for Space Life Sciences

NASA Technical Reports Server (NTRS)

Somps, Chris J.; Hines, John W.; Connolly, John P. (Technical Monitor)

1995-01-01

Sensors 2000! (S2K!) is a NASA Ames Research Center engineering initiative designed to provide biosensor and bio-instrumentation systems technology expertise to NASA's life sciences spaceflight programs. S2K! covers the full spectrum of sensor technology applications, ranging from spaceflight hardware design and fabrication to advanced technology development, transfer and commercialization. S2K! is currently developing sensor systems for space biomedical applications on BION (a Russian biosatellite focused on Rhesus Monkey physiology) and NEUROLAB (a Space Shuttle flight devoted to neuroscience). It's Advanced Technology Development-Biosensors (ATD-B) project focuses efforts in five principle areas: biotelemetry Systems, chemical and biological sensors, physiological sensors, advanced instrumentation architectures, and data and information management. Technologies already developed and tested included, application-specific sensors, preamplifier hybrids, modular programmable signal conditioners, power conditioning and distribution systems, and a fully implantable dual channel biotelemeter. Systems currently under development include a portable receiver system compatible with an off-the-shelf analog biotelemeter, a 4 channel digital biotelemetry system which monitors pH, a multichannel, g-processor based PCM biotelemetry system, and hand-held personal monitoring systems. S2K! technology easily lends itself to telescience and telemedicine applications as a front-end measurement and data acquisition device, suitable for obtaining and configuring physiological information, and processing that information under control from a remote location.

Seeing by touch: evaluation of a soft biologically-inspired artificial fingertip in real-time active touch.

PubMed

Assaf, Tareq; Roke, Calum; Rossiter, Jonathan; Pipe, Tony; Melhuish, Chris

2014-02-07

Effective tactile sensing for artificial platforms remains an open issue in robotics. This study investigates the performance of a soft biologically-inspired artificial fingertip in active exploration tasks. The fingertip sensor replicates the mechanisms within human skin and offers a robust solution that can be used both for tactile sensing and gripping/manipulating objects. The softness of the optical sensor's contact surface also allows safer interactions with objects. High-level tactile features such as edges are extrapolated from the sensor's output and the information is used to generate a tactile image. The work presented in this paper aims to investigate and evaluate this artificial fingertip for 2D shape reconstruction. The sensor was mounted on a robot arm to allow autonomous exploration of different objects. The sensor and a number of human participants were then tested for their abilities to track the raised perimeters of different planar objects and compared. By observing the technique and accuracy of the human subjects, simple but effective parameters were determined in order to evaluate the artificial system's performance. The results prove the capability of the sensor in such active exploration tasks, with a comparable performance to the human subjects despite it using tactile data alone whereas the human participants were also able to use proprioceptive cues.

Left hand tactile agnosia after posterior callosal lesion.

PubMed

Balsamo, Maddalena; Trojano, Luigi; Giamundo, Arcangelo; Grossi, Dario

2008-09-01

We report a patient with a hemorrhagic lesion encroaching upon the posterior third of the corpus callosum but sparing the splenium. She showed marked difficulties in recognizing objects and shapes perceived through her left hand, while she could appreciate elementary sensorial features of items tactually presented to the same hand flawlessly. This picture, corresponding to classical descriptions of unilateral associative tactile agnosia, was associated with finger agnosia of the left hand. This very unusual case report can be interpreted as an instance of disconnection syndrome, and allows a discussion of mechanisms involved in tactile object recognition.

Refreshable tactile displays based on bistable electroactive polymer

NASA Astrophysics Data System (ADS)

Niu, Xiaofan; Brochu, Paul; Salazar, Brandon; Pei, Qibing

2011-04-01

Refreshable tactile displays can significantly improve the education of blind children and the quality of life of people with severe vision impairment. A number of actuator technologies have been investigated. Bistable Electroactive Polymer (BSEP) appears to be well suited for this application. The BSEP exhibits a bistable electrically actuated strain as large as 335%. We present improved refreshable tactile display devices fabricated on thin plastic sheets. Stacked BSEP films were employed to meet the requirements in raised dot height and supporting force. The bistable nature of the actuation reduces the power consumption and simplifies the device operation.

Effect of tactile vibration on annoyance to synthesized propfan noise

NASA Technical Reports Server (NTRS)

Clevenson, S. A.

1981-01-01

Design information that maximizes passenger comfort for propfan aircraft is presented. Predicted noise and vibration environments and the resultant passenger acceptability were studied. The effect of high frequency tactile vibration (i.e., greater than 30 Hz) on passenger reactions was analyzed. Passenger reactions to a wide range of noise with and without tactile vibration was studied. The passenger ride quality simulator was employed using subjects who evaluated either synthesized propeller noises only, or these noises combined with seat/arm vibration. The noises ranging from 80-100 dB consisted of a turbulent boundary layer noise with a factorial combination of five blade passage frequencies (50-200 Hz), two harmonic rolloffs, and three tone/noise ratios. It is indicated that passenger reaction (annoyance) to noise is not significantly changed in the presence of tactile vibration.

New Magnetic Microactuator Design Based on PDMS Elastomer and MEMS Technologies for Tactile Display.

PubMed

Streque, Jeremy; Talbi, Abdelkrim; Pernod, Philippe; Preobrazhensky, Vladimir

2010-01-01

Highly efficient tactile display devices must fulfill technical requirements for tactile stimulation, all the while preserving the lightness and compactness needed for handheld operation. This paper focuses on the elaboration of highly integrated magnetic microactuators for tactile display devices. FEM simulation, conception, fabrication, and characterization of these microactuators are presented in this paper. The current demonstrator offers a 4 × 4 flexible microactuator array with a resolution of 2 mm. Each actuator is composed of a Poly (Dimethyl-Siloxane) (PDMS) elastomeric membrane, magnetically actuated by coil-magnet interaction. It represents a proof of concept for fully integrated MEMS tactile devices, with fair actuation forces provided for a power consumption up to 100 mW per microactuator. The prototypes are destined to provide both static and dynamic tactile sensations, with an optimized membrane geometry for actuation frequencies between DC and 350 Hz. On the basis of preliminary experiments, this display device can offer skin stimulations for various tactile stimuli for applications in the fields of Virtual Reality or Human-Computer Interaction (HCI). Moreover, the elastomeric material used in this device and its global compactness offer great advantages in matter of comfort of use and capabilities of integration in haptic devices.

A new dynamic tactile display for reconfigurable braille: implementation and tests.

PubMed

Motto Ros, Paolo; Dante, Vittorio; Mesin, Luca; Petetti, Erminio; Del Giudice, Paolo; Pasero, Eros

2014-01-01

Different tactile interfaces have been proposed to represent either text (braille) or, in a few cases, tactile large-area screens as replacements for visual displays. None of the implementations so far can be customized to match users' preferences, perceptual differences and skills. Optimal choices in these respects are still debated; we approach a solution by designing a flexible device allowing the user to choose key parameters of tactile transduction. We present here a new dynamic tactile display, a 8 × 8 matrix of plastic pins based on well-established and reliable piezoelectric technology to offer high resolution (pin gap 0.7mm) as well as tunable strength of the pins displacement, and refresh rate up to 50s(-1). It can reproduce arbitrary patterns, allowing it to serve the dual purpose of providing, depending on contingent user needs, tactile rendering of non-character information, and reconfigurable braille rendering. Given the relevance of the latter functionality for the expected average user, we considered testing braille encoding by volunteers a benchmark of primary importance. Tests were performed to assess the acceptance and usability with minimal training, and to check whether the offered flexibility was indeed perceived by the subject as an added value compared to conventional braille devices. Different mappings between braille dots and actual tactile pins were implemented to match user needs. Performances of eight experienced braille readers were defined as the fraction of correct identifications of rendered content. Different information contents were tested (median performance on random strings, words, sentences identification was about 75%, 85%, 98%, respectively, with a significant increase, p < 0.01), obtaining statistically significant improvements in performance during the tests (p < 0.05). Experimental results, together with qualitative ratings provided by the subjects, show a good acceptance and the effectiveness of the proposed solution.