Design & characterization of a bio-inspired 3-DOF Tactile/Force sensor and implementation on a 3-DOF decoupled parallel mechanism for human-robot interaction purposes

Abstract

This paper presents the design and implementation of a Tactile/Force sensor which has been used on a 3-DOF decoupled parallel mechanism for Human-Robot Interaction purposes.The sensor, called HexaTactile, is a soft tactile sensor array based on six MEMS barometers, where each of them is covered by a silicone layer in the form of an incomplete pyramid. HexaTactile consists of six soft and highly sensitive tactile modules which are placed on six sides of a cube to allow simultaneous measurement of the force in the positive and negative directions along the x, y and z axes. Some of the advantages of this sensor can be regarded as its high precision, excellent linearity (coefficient of determination r2=0.99), low cost and low noise. The accuracy of the sensor is 0.01 N, within a range of 4 N and therefore HexaTactile can be suitably attached to a robot end-effector for human-robot interaction applications. Then, using the proposed force sensor some control scenarios, including fixed admittance control and active admittance control are applied for human-robot interaction purposes. From the experimental tests, it has been revealed that the active admittance control solved the drawbacks of fixed admittance control, for the considered case studies.