Simulation of enhanced force limiting gripper for bilateral teleoperation

Abstract

This paper proposes an enhanced force limiting gripper to avoid object deformation when it is in contact with the slave due to excessive forces imposed by the master operator in bilateral control. The force lock protects the gripped object on the slave and the attainment of the force limit is notified to the master operator via a small vibration. Master operator is expected to experience a spring effect if the operator presses his leaver towards the force increasing direction. The continuous copying of the slave position as the reference to the virtual spring controller’s spring equilibrium point allows smooth releasing. In addition to vibration the loss of reaction force coming from the slave environment could also be sensed by the master operator. Reversing of the applied force on master handle releases the object attached to the slave. In this proposed system sensor-less sensing is used. Disturbance Observer is used to estimate disturbances and Reaction Force Observer estimates reaction forces. The proposed gripper is having a jaw opening of 0.15 m which has linear 1-DOF. Simulation is conducted using real world linear motor parameters and simulation results prove the applicability of proposed system.