改进Twisting算法的相对位姿耦合控制

Relative position and attitude coupled control based on modified twisting algorithm

摘要:

为实现对非合作目标航天器进行在轨服务,将Twisting算法与线性补偿项相结合,设计相对位置与姿态耦合的二阶滑模控制器. 以航天器对接端口间耦合相对运动模型为基础,设计两种滑模平面的改进Twisting控制器. 选取严格李雅普诺夫函数,证明所设计的改进Twisting控制器对有界干扰具有有限时间收敛的特性,并估计出收敛时间的上界. 设计数学仿真,将其与标准Twisting算法进行对比,验证所设计的二阶滑模控制器对模型不确定性及有界干扰具有较强的鲁棒性,并能够有效抑制执行机构的震颤.

Abstract:

The relative position and attitude coupled second-order sliding mode controller is proposed by combining twisting algorithm with linear compensator for on-orbit servicing to a non-cooperative target spacecraft. On the basis of a coupled relative motion model between docking ports on two spacecrafts, the modified twisting controllers with linear compensation items are designed by using two different sliding surfaces. A strict Lyapunov function is proposed to prove that the modified twisting controllers have the property of finite time convergence for bounded perturbations and the upper bound for the time convergence is estimated. Simulation results are presented to validate strong robustness of the proposed second-order controllers for model uncertainties and limited perturbations with the comparison with the standard twisting algorithm. The chattering alleviation and attenuation is also achieved in actuating mechanism.