A variable impedance control architecture for transparency improvement in nonlinear bilateral telerobotic systems

Abstract

This study presents the design, comprehensive analysis, and implementation of a nonlinear bilateral telerobotic system operating in a master-slave configuration. It focuses on the critical importance of transparency, which is essential for achieving realistic force feedback in bilateral teleoperation. While some prior research has investigated the concept of transparency in nonlinear systems, this work represents the first attempt to implement variable impedance control, along with real-time parameter estimation through adaptive rules, to achieve transparency in a nonlinear bilateral teleoperation system. The suggested approach combines robust position control with impedance-based force regulation, while an Extended Kalman Filter (EKF) estimates environmental stiffness and damping parameters online. This synthesis enables the system to adapt to variable interaction conditions and maintain stable and high-fidelity force reflection. In addition, the presented stability analysis using the Lyapunov-based approach guarantees the theoretical robustness of the system under various operating conditions. Extensive simulation studies are presented to confirm the potential of the proposed approach, and the implementation results also validate its practical reliability and effectiveness. This makes the system well-suited for advanced teleoperation, haptic interfaces, and other domains requiring precise control and accurate force reflection capabilities. © 2025 Informa UK Limited, trading as Taylor & Francis Group.