A scalable, high resolution strain sensing matrix suitable for tactile transduction

摘要

The integration of tactile information, such as contact area, displacement magnitude, velocity, and acceleration, is paramount to the optimization of robotics in human-centric environments. Cost effective embeddable sensors with scalable receptive field size and strain sensitivity are not readily commercially available and would benefit investigations of in situ tissue mechanics. We describe the design and performance of a scalable sensor matrix that transduces fine parameters of strain and is made of combinable "modules". The sensors transduce static and dynamic strains of both uniaxial and multi-dimensional nature. Modules consist of three silicon wafers placed on top of and three on the bottom of a hexagonal collar, wafers are thus positioned 120 degrees to one another to facilitate force vector extrapolation. Analog signals from each sensor can be easily compared to neighboring sensor output to determine mechanical phenomena such as slip or shear. The smallest of our prototype multiunit matrices consisted of seven hexes in a honeycomb orientation of 4.1 mm diameter (containing 42 silicon gauges). Unamplified, unshielded output from this embodiment (3 V-exc button cell) yielded 1 mV from 5 mu m displacement. Transduction linearity was high (R>0.99 nearest displacement) and exhibited nominal hysteresis. Modules may be placed upon or embedded into a multitude of materials and the size of individual hexagons may be scaled for favorable stiffness to strain ratio and to scale receptive field. Given the scalability of matrix size and resolution, we believe the sensor matrices could benefit the fields of prosthetics, robotics, and physiologic investigation of tissue mechanics. (C) 2015 Elsevier Ltd. All rights reserved.