大挠性航天器的自触发模型预测控制

Self-triggered model predictive control of large flexible spacecraft

针对大挠性附件的剧烈振动严重影响大型挠性航天器姿态精度的问题,设计了基于自触发机制的模型预测姿态控制策略。不同于传统模型预测控制策略需要在每个采样时刻求出最优控制序列,自触发模型预测控制仅在触发时刻求解优化问题算出最优控制序列。根据自触发算法计算下一个触发时刻和预测时域,在到达下一个触发时刻前,取最优控制序列中前几步控制量施加到实际系统中,从而降低优化问题的求解频率,缩短控制策略的在线计算时间。所设计的自触发控制可使系统状态快速进入终端集,而后切换为状态反馈控制姿态快速跟踪上期望值。最后,开展了仿真校验。仿真结果表明,所设计的控制算法能控制大挠性航天器迅速达到期望姿态,具有较好的控制特性。

Considering the problem that the vibration of the large flexible appendage seriously affects the attitude accuracy of large flexible spacecraft,a self-triggered model predictive attitude control strategy is designed.Different from traditional model predictive control that needs to solve the optimal problem at each sampling time,the self-triggered predictive control only solves the optimal problem at the control sequence update time,so as to obtain the optimal control sequence.The next updating control instant and predictive horizon are determined by the self-triggered strategy.Before the next updating control instant,the first several steps of the optimal control sequence are applied to the actual system,thereby reducing the frequency of solving the optimization problem and shortening the online calculation time of the control strategy.Thus the system state can quickly enter the terminal area by employing the designed self-triggered predictive control,and then the system state can rapidly track the expected value through the state feedback control law.Finally,the simulation verification was carried out.The simulation results show that the designed control algorithm can control the large flexible spacecraft to reach the desired attitude quickly and has better control performance.