Adaptive variable impedance control methods in dynamic environments

Aiming at the problem of contact force tracking fluctuation caused by inaccurate environment modeling in robot contact operation, an adaptive variable impedance control method in dynamic environment was proposed. The proposed control method establishes the adaptive control rate of the inertial parameters according to the contact force feedback information and dynamically adjusts the damping update rate to avoid the force overshoot in the contact phase and reduce the force tracking error in the steady state tracking phase. The simulation model is built based on Matlab/Simulink and compared with the classical fixed impedance control in the plane, inclined plane and sinusoidal surface environment. The experimental results show that compared with the classical fixed impedance control, the proposed method can reduce the steady-state error of force tracking by at least 2.33 N and the overwork by at least 97.9% under constant expected force. The desired force dynamic changes also have smaller overshoot and steady-state errors, and fewer oscillation times when the stiffness changes abruptly, which can well adapt to the dynamic changes of the contact environment position, inaccurate stiffness parameters, and dynamic changes of the force.