漂浮基柔性两杆空间机械臂基于状态观测器的鲁棒控制及振动控制

Observer Based Robust Control and Vibration Control for a Free-floating flexible Space Manipulator

讨论了漂浮基柔性空间机械臂基于状态观测器的鲁棒控制及振动最优控制问题。首先通过合理选择联体坐标系,实现两柔性杆弹性变形之间的解耦;根据拉格朗日方程与动量守恒原理,建立了载体位置无控、姿态受控飘浮基两杆柔性空间机械臂系统的动力学方程。接着利用奇异摄动法,将这个柔性两杆空间机械臂系统分解为一个慢变子系统与一个快变子系统。以此为基础,提出了一个包含慢变控制项与快变控制项的复合控制器。利用动态滑模观测器得到慢变子系统的观测速度矢量,基于这个观测速度矢量设计系统的鲁棒慢变控制律来实现载体姿态、关节轨迹的跟踪。利用线性观测器得到快变子系统的观测速度矢量,基于这个观测速度矢量与线性系统的最优控制理论设计系统的快变控制力矩,实现两柔性杆振动的抑制。最后通过系统的数值仿真,证实了方法的有效性。

The robust control based on observers is proposed for a free-floating flexible space manipulator.Firstly the interactions of flexible motion of the two flexible links are decoupled by choosing appropriate local coordinate frame;the dynamic model of a free-floating two-flexible-links space manipulator is established by the Lagrange equations and the momentum conservation.Secondly singular perturbation model of the space flexible manipulator system is obtained by using two-time scale control theory,in which the system is decoupled into slow（rigid） and fast（flexible） subsystems.Then an observer based robust composite controller which consists of a slow control component and a fast control component is proposed.A sliding velocity observer based robust control algorithm is applied to control the slow subsystem to track the desired trajectory.The fast controller is designed with the estimated velocity by a linear state observer to damp out the vibration of the flexible links using optimal Linear Quadratic Regulator（LQR） method.Finally the numerical simulation is carried out,which demonstrates the controller proposed is feasible and effective.