Modified PD based bilateral nonlinear teleoperation with flexible link robots

In this paper, a new control scheme for bilateral teleoperation system with flexible link slave robot is addressed. In this regard, Modified collocated Proportional-Derivative (MPD) controller is suggested for flexible slave robot. The MPD control structure includes some vibration feedback terms to enhance the response of the flexible arm without necessity of additional sensors and knowledge of dynamic parameters. This approach utilizes capability of strain feedback in controller to reduce vibration at robot´s end tip while PD part guarantee stable rigid body motion of the system. Stability of the bilateral teleoperation system under variable communication delays is proved based on Partial Differential Equation´s (PDE) of system dynamics using Lyapunov method. Hence, the drawbacks of truncated-model-based methods are prevented. Experimental results for one DOF flexible teleoperation system validate improvement properties of presented framework in terms of trajectory tracking and force reflection.