A tactile sensing system (TSS) for articulated robotic hands is described. The system is composed of flexible touch sensing arrays, access electronics, and algorithms for data sampling and processing. The TSS is meant to exist in a multiprocessing control environment and is designed to keep low-level procedures such as sensor addressing and data access off of the control system's shared bus. Up to 16 arrays of 256 taxels each can be accessed in parallel with achieved sampling rates of more than 60 Hz. The resolution of the sensors can be dynamically modified by a simple switching technique. This allows very fast sampling rates at low resolution while retaining the ability to sample with high precision at lower rates. Variance of the resolution changes only the number of taxels and the size of their receptive fields but does not affect the coverage of the array.As part of the discussion about TSS, a generic class of resistive touch sensors is described. These sensors are inexpensive, flexible, and easy to build. Methods for efficient sampling, variable resolution, and shear force detection are introduced, and implementation issues for use with the Utah/ MIT Dextrous Hand are discussed.

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Manipulation by teleoperation (telemanipulation) offers an apparently straightforward and less computationally expensive route toward dextrous robotic manipulation than automated control of multifingered robotic hands. The functional transformation of human hand motions into equivalent robotic hand motions, however, presents both conceptual and analytical problems. This paper reviews and proposes algorithmic methods for transforming the actions of human hands into equivalent actions of slave multifingered robotic hands. Forward positional transformation is considered only, the design of master devices, feedforward dynamics, and force feedback are not considered although their importance for successful telemanipulation is understood. Linear, nonlinear, and functional mappings are discussed along with performance and computational considerations.

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This article presents a method for determining threedimensional stress and strain tensors within elastic layers covering or embedding tactile sensors. When an object comes in contact with the elastic surface of a sensing array, the distribution of forces on the surface is mechanically filtered before reaching the underlying sensing elements. In order to predict the response of embedded sensors and to understand the nature of the transduced variables, the relationship between surface forces and interior stress and strain tensors must be known. To determine this, we need to know the shape of the surface contact area and the distribution of forces over that area, both normal and tangential. The algorithm described here discretizes the known surface force distribution into a dense array of independent point loads, approximating the surface force profile. The stress field produced by a single normal and/or a single tangential point load can be expressed analytically, given the elasticity and compressibility of the material. Fields for each point load are calculated and can be summed to determine the resultant stress tensor at any point within the medium. Strains can be computed from stresses using a simple set of translation formulas.A detailed example is illustrated, analyzing the interaction between a sphere and a planar elastic half space. From the example the relative effects of depth and distance from the center of contact on the response of underlying sensors is discussed. Using results from the example, methods are proposed to exploit sensors at different depths and at different orientations within the medium. An algorithm for determining the direction of surface tangential forces and a method for determining the ratio between normal and tangential forces are analyzed, using unidirectionally sensitive sensors at different depths in the elastic layer.