空间机器人抓捕目标后姿态接管控制

Attitude takeover control after capture of target by a space robot

针对姿轨控系统已经失效的目标航天器姿态控制问题,提出一种空间机器人抓捕目标后姿态接管控制方法。该方法首先利用空间机器人抓捕目标航天器,并保持在固定构型形成组合航天器;其次确定参数突变后组合航天器新的惯量主轴、主惯量和控制力矩分配矩阵;然后在状态空间建立组合航天器的非线性误差姿态动力学;最后采用-α稳定度设计方法来设计服务航天器的SDRE姿态接管控制器,并通过θ-D求解方法得到SDRE控制器的次最优控制律,实现服务航天器对目标航天器的姿态接管控制。仿真结果表明,相比传统的SDRE控制器设计,基于-α稳定度设计的SDRE控制器能够使得系统闭环极点远离虚轴,θ-D求解方法可以降低计算量,因此具有更好的稳定性和实时性。

For the attitude control of target spacecraft whose attitude and orbit control systems have failed, a takeover control approach is proposed that the attitude is controlled after capture of target spacecraft by a space robot. Firstly, the space robot captures a target spacecraft and remains in a fixed configuration to form a combined spacecraft. Then, the new princi- pal axes of inertia, main inertia and allocation matrix of control torque of the combined spacecraft are determined due to the parameter mutation of the combined spacecraft. Furthermore, the attitude error dynamics of the combined spacecraft is established in the form of state space. Finally, the SDRE takeover controller is constructed based on the - α stability design for the service spacecraft, which is solved by the 8-D method to obtain the sub-optimal control law of SDRE controller and achieve the takeover control of target spacecraft attitude by the service spacecraft. Numerical simulations have demonstrated that compared with the traditional SDRE control, the SDRE controller based on the - α stability design can make the closed-loop poles of system away from the imaginary axis, and the 8-D solving method can reduce the computation burden, hence it has better stability and real-time performance.