Implementation of Sensory Feedback and Trajectory Tracking in Active Telemanipulation Systems

Abstract

This paper presents an approach to the implementation of sensory feedback in a robotic telemanipulation system. The system considered here consists of kinematically similar master-slave robotic manipulators. We propose a control scheme whereby the slave tracks the motion commanded by the human operator through the master mechanism. The scheme also accommodates, in a unified manner, different sources of sensory feedback. These include combined effects of the interaction with unknown environments and changes in structural properties of the slave manipulator due to additional unknown loads. The control algorithm is based on continuously sliding variable structure control, which is a nonlinear and highly robust control scheme. Due to the robustness of the scheme, the need for a priori information about the environment and the load is minimal. This information can be passed on to the system in the form of upper bounds of the interaction forces and additional loads. Experimental studies with a Pneumatic Haptic Interface (PHI) system were conducted to evaluate the performance of the proposed scheme. We used a virtual slave with percent 25 uncertainty to verify the robustness of the controller. We have shown that the proposed scheme can accurately estimate the environmental interaction torques and can robustly track the trajectories commanded by the human operator.