漂浮基空间机器人自适应 RBF 网络终端滑模控制

摘要

主要研究漂浮基空间机器人对工作空间连续轨迹跟踪控制问题。针对系统动力学模型中非线性项未知，以及参数不确定性和外界扰动无法估计的情况，提出了基于自适应 RBF 网络终端滑模控制方法。该方法结合了非线性滑动流形与径向基函数特性，利用自适应 RBF 网络在线学习系统中的不确定性，使得无需精确的动力学模型亦能保证系统在有限时间内快速稳定。根据 Lyapunov 方法设计的自适应增益保证闭环控制系统具有全局稳定性，并且有效抑制抖振现象。针对6关节空间机器人的轨迹跟踪控制仿真表明，提出的自适应 RBF 网络终端滑模控制方法能够基于不完整动力学模型实现高精度轨迹跟踪，且误差在有限时间内快速收敛，系统抖振也得到了有效抑制。%Continuous trajectory tracking control in task space of free-floating space robots was investigated.An adaptive RBF based terminal sliding mode control method was proposed for a dynamics model with unknown non-linear terms,parametric uncertainties and unbounded external disturbances.The proposed method combinesthe properties of a nonlinear sliding manifold with that of a radial basis function,where the adaptive RBF network is used to estimate the unknown parts of the system on line,such that rapid convergence of control errors in finite time are guaranteed without the exact dynamics mode of the system.The adaptive updating laws were designed according to Lyapunov approach,which make the closed-loop control system globally stable and eliminate chatte-ring problems.A six-link free-floating space robot was employed to validate the proposed method.The simulation results show that the adaptive RBF based terminal sliding mode control method provides high precision perform-ances without the exact dynamics model.Meanwhile,the chattering problems were eliminated effectively.