不同重力环境的空间机械臂自抗扰轨迹跟踪控制

针对空间机械臂在地面装调与空间应用时,由于重力环境变化导致机械臂模型发生变化的问题,提出了一种自抗扰控制算法,用于完成空间机械臂轨迹跟踪控制的任务.该算法通过将系统模型及未知外扰作为系统的总和扰动,并利用扩张状态观测器对该扰动进行观测且给予补偿,从而提高了系统抗扰的性能.当机械臂模型随重力环境变化而发生变化时,使用同一个自抗扰控制器对其末端轨迹进行控制,均能取得较好的控制效果.通过对系统的稳定性进行分析,证明了所设计控制器的有效性.将仿真结果与PD控制及自适应鲁棒控制做比较,结果表明该控制算法不仅能适应机械臂模型的变化而且还能有效抵抗系统的扰动,从而使系统具有较强的鲁棒性.

Trajectory tracking control with active disturbance rejection for space manipulator in different gravity environments

The active disturbance rejection control (ADRC) method is proposed to cope with the model change in the space manipulator caused by the variations of gravity, when it is aligned on the ground and applied in the space. In this method, we treated the model change and the unknown disturbances as the total system disturbance which is observed and compensated by means of an extended state observer (ESO). Simulation results show that good trajectory tracking results can be achieved with ADRC even when the model is changing. The effectiveness of the proposed control law is further verified by the theoretical analysis of the system stability. This control algorithm not only adapts to the model change and rejects the system disturbance as shown in the simulation, but also improves the system robustness in comparison to the PD control and adaptive robust control.