大型空间机械臂柔性关节的微分几何算法控制器设计

Controller design of large space manipulator flexible joint using differential geometry algorithm

大型空间机械臂负责空间站大型负载的运输、装配,而关节柔性会在一些工况下造成振动.因此设计了一种大型空间机械臂柔性关节控制器.针对谐波减速器的引入而带来的柔性,建立了柔性关节的动力学模型;采用基于微分几何反馈线性化方法对柔性关节模型做了精确线性化解耦处理.对于线性化后的系统,为了克服不确定性及提高鲁棒性,采用具有较高鲁棒性和抗干扰性的滑模变结构控制规律来实现轨迹的合理跟踪.在Matlab/simulink中实现了线性化过程和滑模控制过程,对给定输入信号进行跟踪仿真,改变滑模控制的控制参数,得到控制参数对系统影响,验证了滑模控制的高鲁棒性,并能很好地跟踪输入信号.仿真结果表明,反馈线性化与和滑模控制的结合可以很好地应用于柔性机械臂的控制.

During the transporting and assembling on a space station by a large space manipulator under heavy load, vibration may occur caused by flexible joint under certain working conditions, which is introduced by the harmonic reducer. Aiming at this problem, this paper presents a controller design of large space manipulator flexible joint. A dynamic model of the flexible joint was established. Based on the knowledge of feedback linearization in differential geometry, the nonlinear model of flexible joint was transformed to a linear model which could be decoupled precise- ly. To overcome uncertainty and increase robustness of the system after linearization, a sliding-mode variable-struc- ture control law having high robustness and anti-interference performance was chosen to track the ideal orbit. The linearization process and sliding mode control process were accomplished by using the Matlab/Simulink, by the tracking and simulation of given input signals and by changing the control parameter of the sliding mode control, the influence of control parameter on the system was derived. The high robustness of the sliding mode control was veri- fied and the input signals were tracked very well. The simulation results showed the combination of feedback linear- ization and sliding mode control can be applied to control the flexible joint.