Active Disturbance Rejection Control of Underwater Manipulator

Qirong Tang, Daopeng Jin, Yang Hong, Jinyuan Guo, Jiang Li

Abstract: In this study, a method of active disturbance rejection controller (ADRC) is presented for 2-DOF underwater manipulator. The ADRC basically does not rely on the accurate mathematical model of the object and can decouple the model. This method can eliminate the influence of model errors, time-varying parameters and external interference on the control effect. Firstly, the manipulators is divided into two subsystems. For each joint subsystem, the hydrodynamic force, coupling term between joints and unknown environment disturbances are considered as the total disturbance. Subsequently, an extended state observer (ESO) is designed to estimate and compensate the total disturbance. Moreover, in order to improve the disturbance observation effect of the extended state observer, the inertia matrix of the manipulator system is used to decouple the static part. Finally, the effectiveness of ADRC is verified by simulation and it is demonstrated that ADRC’s control effect outperforms PD and CSMC in either accuracy, dynamic characteristics or robustness.