Tactile sensors

Hennig E M 1988 Piezoelectric sensors Encyclopedia of Medical Devices and Instrumentation ed J G Webster (New York Wiley) pp 2310-9 Webster J G (ed) 1988 Tactile Sensors for Robotics and Medicine (New York Wiley)... 

The incorporation of tactile sensors into grippers allows for increased reliability and easier programming. 

The most straightforward type of tactile sensor. used consists of a contact switch which provides binary high-low information. Other types of mechanism such as strain gauges and carbon fibre materials change their electric resistance under stress, whereas piezoelectric materials generate an electric charge when subjected to mechanical strain. 

Obviously, reproducing the human sense of touch with an artificial system is a very challenging task, primarily, because the term touch is actually the combined term for several senses. Research and development on tactile sensing has experienced an impressive growth in the last three decades, and several kinds of materials and techniques have been proposed. The tentative specifications for tactile sensors have been defined [54] as ... 

Tactical naval decision making system (TANDEM), 922 Tactile sensors, 385 Taguchi method, 2232 TAKD, see Task analysis for knowledge description... 

Textile sensors can be employed to detect the position and/or movement of a person lying on a mattress or similar textile structure. The measured values can be mechanical pressure or deformation of the textile. In general tactile sensors can be applied for both physical values. 

The term tactile sensor usually refers to a transducer that is sensitive to touch, force, or pressure. Tactile sensors are employed wherever interactions between a contact surface and the environment have to be measured and registered. Tactile sensors are useful in a wide variety of applications for robotics and computer hardware and even security systems. 

A soisor s sensitivity indicates how much the sensor s output changes when the measured quantity changes. The term tactile refers to the sense of touch. A tactile sensor is a device that receives and responds to a signal or stimulus having to do with force. 

Tactile sensors are generally known and can be grouped into a number of types depending upon their constraction. 

Surface roughness measurement can be characterized using either quantitative or qualitative methods. Qualitative techniques include optical appearance such as the reflectivity of a surface or the strength of the machining lay as well as dragging a thumbnail across the surface as a crude tactile sensor. Quantitative analysis has evolved from simple two-dimensional profilometry to more advanced three-dimensional area analysis where information regarding surface structure can be easily obtained. 

The earliest ways of measuring surfaces were by using the thumbnail as a tactile sensor or the eyes. Both techniques are highly effective but are completely subjective. Demand for quantitative results led to the development of two distinct branches of instrumentation, one following the tactile approach the other mimicking the eyes. 

There are different technologies available for the development of tactile sensors such as optical [1], capacitive [2], resistive [3] and micro electro mechanical systems (MEMS) [4] technologies. Each suffers from a limitation, for example capacitive sensors are... 

Table 10.1 Specification of a human s finger-tip tactile sensors ...

Bonomo, C., Brunetto, P., Fortuna, L., Giaimone, P., Graziani, S. and Strazzeri, S. (2008). A tactile sensor for biomedical applications based on IPMCs, IEEE Sensors Journal 8, pp. 1486-1493. 

Wang, J., Xn, C., Taya, M. and Knga, Y. (2007). Design and fabrication of tactile sensors based on electroactive polymer composites, (SPIE), p. 65241K. 

Sensors , which are used to boost performance in intelligent robots. They can be sorted according to type, physical and computational foundation, fixed or mobile and of the contact (force and tactile sensors) or noncontact type (vision, proximity, and range sensors). 

Uses and applications electrical wires, tactile sensor arrays, strain gauges, audio transducers, piezoelectric panels, lithium ion batteries, monofilament fishing line, membranes. 

In the following, adaptronic systems for biomedical applications have been selected that illustrate recent activities in the field. An emphasis is given on systems that employ microtechnologies. The described microsystems comprise electronic implants, as advanced pacemakers and neural prostheses as well as adapting diagnostic devices, as tactile sensors and self-adjusting blood flow monitors. 

KYNAR Piezo film applications include a noise-cancelling telephone headset, infrared sensing, anti-intrusion devices, an ultrasonic gas flow respiration monitor, and a high-fidelity electric violin. Other potential uses now in development include computer switches, keyboards and printers, ultrasonic imaging systems for medical diagnosis, and robotic tactile sensors. 

Adam M, Mohacsy T, Jonas P, Ducso C, Vazsonyi E, Barsony 1 (2008) CMOS integrated tactile sensor array by porous Si bulk micromachining. Sens Actuators A 142 192-195... 

Dynamometers/load cells Piezoelectric load cells Tactile sensor Ultrasonic stress sensor... 

Micro CCD image sensor Fiberscope Micro-ultrasonic sensor Micro-tactile sensor Small size, full field image sensor Small (0.2 mm diameter) field vision scope using SMAcoil actuators Detects flaws in small pipes Detects proximity between the end of catheter and blood vessels... 

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