Active disturbance rejection control for trajectory tracking of space manipulator flexible joint

The high-precision trajectory tracking control for space manipulator flexible joint is researched. The second-order cascade dynamics equations with motor uncertainties and load disturbance of flexible joint are established. A control strategy of active disturbance rejection control (ADRC) and double closed-loop control is presented based on cascade systems. Both the inner and outer loops are designed by active disturbance rejection controllers. In this method the disturbances are estimated using extended state observer (ESO) and compensated during each sampling period. The designed controller not only satisfies the quick response speed and steady-state accuracy demands, but also effectively resists to the motor uncertainties and the load disturbance. Control algorithm is simple and it is easy to digital implement. The simulation results indicate that the designed of the double closed-loop control system has high-precision and stronger robustness and has important engineering significance.