Variable Impedance Control for a Robotic Leg with External Uncertainties

Abstract

This paper presents an adaptive variable impedance controller combinations for ground reaction force (GRF) control of an active robotic leg with external uncertainties. An adaptive control scheme is used to handle the parameters of the dynamic in any environment stiffness uncertainties, and a robust control scheme so the convergence of tracking errors was flaunted robustness to differences of GRF. The boundary surface not only obtains optimal impedance parameters but also bounds control gains to compromise between the two conflicting objectives of trajectory tracking. Furthermore, stability and convergence characteristic of the controlled system is demonstrated for a stable force tracking execution. Finally, simulation results are shown the high steady-state tracking performance of joint movements and reasonable control to verify the efficacy of the controller for different challenging model parameters.