Accession Number : ADA324721

Title :   Peripheral Neural Mechanisms of Haptic Touch: Softness and Shape.

Descriptive Note : Final rept. 1 Mar 91-30 Jun 94,

Corporate Author : YALE UNIV NEW HAVEN CT SCHOOL OF MEDICINE

Personal Author(s) : LaMotte, Robert H. ; Srinivasan, Mandayam A. ; Annaswamy, A. M.

PDF Url : ADA324721

Report Date : 24 JUL 1995

Pagination or Media Count : 15

Abstract : The aims and accomplishments of this research were threefold: (1) develop a high precision electromechanical stimulator capable of indenting or stroking stimulus objects across the primate fingerpad under position or force control; (2) investigate how the primate tactual system achieves the sensing of shape and softness of objects and (3) develop a computational theory of haptics suitable for both humans and robots. Using a 4-axis servo controlled tactile stimulator to apply two- and three-dimensional shapes to the monkey fingerpad while electrophysiologically recording responses in slowly- and rapidly- adapting mechanoreceptive nerve fibers (SAs and RAs) it was discovered that spatial parameters of shape were most accurately encoded in the spatially distributed discharge rates of the SA population. In other studies, optimal tactual discriminations of the softness required tactile cues alone for deformable surfaces (mbber) but kinesthetic as well as tactile cues for non-deformable compliant objects. A computational theory using a 3D half-space model of the human and robot finger subjected to arbitrary pressure or displacement loading in any direction gave explicit formulae for coding and decoding. The dynamic interactions occurring between compliant end-effectors and deformable objects were modeled using adaptive control algorithms. The theoretical results can be used to generate testable hypotheses for experiments on human or robot haptics.

Descriptors :   *SPATIAL DISTRIBUTION, *COMPUTATIONS, *SHAPE, *NERVOUS SYSTEM, *MECHANICAL COMPONENTS, *NERVE FIBERS, ALGORITHMS, CONTROL, STIMULATION(PHYSIOLOGY), STIMULATION(GENERAL), ADAPTIVE CONTROL SYSTEMS, DISTRIBUTION, HUMANS, INTERACTIONS, DYNAMICS, PARAMETERS, DEFORMATION, DISPLACEMENT, THEORY, ROBOTS, ELASTIC PROPERTIES, TEST METHODS, POPULATION, CODING, THREE DIMENSIONAL, ELECTROMECHANICAL DEVICES, RESPONSE, PRECISION, RECORDING SYSTEMS, HYPOTHESES, DECODING, FINGERS.

Subject Categories : Computer Programming and Software
      Cybernetics

Distribution Statement : APPROVED FOR PUBLIC RELEASE