Active disturbance rejection control based on inertia estimation and variable gain for servomechanism of industrial robot

Abstract

This paper proposes an adaptive PID controller based on linear extended state observer (LESO) for the two-degree-of-freedom joint servomechanism of industrial robot with time-varying load, uncertainties of parameters and disturbance. The third-order extended state space equations of the system approximate model is established to obtain LESO which is applied to estimate the state values and the total disturbance. The model reference adaptive algorithm is used to estimate the variable moment of inertia to design the controller parameter for control law which is designed with disturbance compensation. By appropriately selecting the adaptive gain coefficient of model reference adaptive algorithm and the bandwidth of LESO, the influences of parameter uncertainty, unknown dynamics and disturbances are effectively attenuated. Simulation and experimental results show that the proposed method achieves both satisfactory disturbance rejection and tracking performances of the two-degree-of-freedom joint servomechanism.