Document Type
Thesis
Date of Award
5-31-1988
Degree Name
Master of Science in Electrical Engineering - (M.S.)
Department
Electrical Engineering
First Advisor
William N. Carr
Second Advisor
Onofrio L. Russo
Third Advisor
Michael Pratap Singh
Abstract
This thesis details the design of a new tactile sensor for general-purpose robot manipulators. Such manipulators, designed to be functionally equivalent to the human hand, will require sensor arrays that fulfill several requirements : (1) many sensor elements to minimize tactile imaging time, (2) close spacing of small sensing elements for fine spatial discrimination, (3) ability to be molded to a convex fingertip surface for taction on concave surfaces, (4) tolerance to over-scale forces without damage. In addition to the above, which are considered requirements, several other characteristics are desirable. Foremost is the ability to sense shear forces, which provide information on actual or incipient slip of a grasped object. It also appears desirable for tactile sensor arrays to possess some local signal - processing capability which can lower the transmission bandwidth required to the robot's central information processor.
This tactile sensor treats shear and normal force sensing separately. The normal force sensing element employ piezoelectric property of ZnO thin film , and the piezoresistive effect of silicon crystal are used in shear force sensing. Both of these technologies are generally compatible with CMOS signal processing circuits. The voltage resposes (at 300°K) are 5.2 V/N, 10.2 V/N for normal and shear-sensing respectively. Loading rang of shear force sensing piezoresistive bridge is estimated about from 0 to 300 mN. Simarily, 5 - 100 mN for the loading rang of normal force sensing element (ZnO piezoelectric capacitor).
There is an on - chip CMOS signal conditioning circuit to process the analog signals which are obtained from sensor array and convert them to a five bits digital output. The bit 0 represents the direction of applied forces. Bit 1 to bit 4 describe the magnitude of applied forces.
Recommended Citation
Cho, Sin-Shou, "A 3-D tactile sensor with digital output" (1988). Theses. 3035.
https://digitalcommons.njit.edu/theses/3035
