具有外部扰动及不确定系统参数的漂浮基空间机器人关节运动的增广鲁棒控制

讨论了载体位置与姿态均不受控制的漂浮基空间机器人系统的鲁棒控制问题. 利用拉格朗日方法及系统动量守恒关系导出了漂浮基空间机器人欠驱动形式的系统动力学方程, 以确保得到的系统动力学方程关于一组适当选择的组合惯性参数呈线性函数关系. 在此基础上, 借助增广变量法针对末端爪手所持载荷参数存在不确定的情况, 提出了对外部扰动具有鲁棒性的漂浮基空间机器人关节空间轨迹跟踪的拟增广鲁棒控制方案. 所提控制方案由于充分利用空间机器人系统动量守恒关系, 消除了动力学方程中载体位置相关量, 因此具有不需要测量、反馈载体的位置、移动速度和移动加速度的显著优点; 且由于对系统不确定参数及外部扰动始终采用保持鲁棒性的方式而非在线估计的方式, 有效减少了计算量, 因此更适用于机载计算机运算能力有限的空间机器人控制系统实时在线应用. 一个平面两杆空间机器人系统的数值模拟仿真, 证实了方法的有效性.

Robust Control for Space-based Robot With External Disturbances and Uncertain Parameters in Joint Space

The robust control problems were discussed for space-based robot system whose base was not controlled. The under-actuated dynamic equations of the system were derived through the Lagrange method and linear momentum conservation of the system. It was shown that the dynamic equations mentioned above can be linearly dependent on a group of inertial parameters.Based on the results and with the augmentation approach, a robust control scheme was developed for space-based robot system with uncertain payload parameters and external disturbances to track the desired trajectory in joint space. The control scheme proposed doesn't require measuring the position, velocity and acceleration of the base with respect to the orbit due to an effective exploitation of the system dynamics. Besides, it is computationally simple, because the controller is always robust to the uncertain parameters and external disturbances rather than explicitly estimating them online.Therefore, the control scheme is prone to real-time and on-line applications in space-based robot system. A two-link planar space-based robot system was simulated to verify the proposed control scheme.