自由漂浮柔性航天器的非线性扰动观测器设计  

Nonlinear Disturbance Observer Design for Free-Floating Flexible Spacecrafts

作　　者：孙凯鹏[1] 廖鹤[1] 赵艳彬[1] 陈提 许域菲[1] 毕振瀚 

机构地区：[1]上海卫星工程研究所,上海201109 [2]南京航空航天大学机械结构力学及控制国家重点实验室,江苏南京210016

出　　处：《上海航天》2017年第5期54-58,共5页Aerospace Shanghai

基　　金：国家自然科学基金资助(11602145);国家重点研发计划专项资助(2016YFB0500801);上海市科学技术委员会启明星计划(B类)资助(16QB1403500)

摘　　要：为提高控制策略的效率,考虑航天器的平动和转动与柔性附件的振动相互耦合作用,对一种用于估计柔性附件对自由漂浮航天器主体平动和姿态转动影响的非线性扰动观测器(NDO)设计进行了研究。将自由漂浮航天器简化为自由运动的中心刚体柔性梁(FHB)系统,用浮动坐标系建立了系统的动力学模型,并用假设模态法对柔性附件进行离散以方便计算。将与不可观测状态相关的项作为等效扰动项,并假设其为慢变且有界,设计了扰动观测器。因考虑了柔性附件对航天位姿的扰动,设计的扰动观测器具渐近收敛性和鲁棒性。构建了Lyapunov函数,从理论上证明了该观测器的收敛性。用无外力输入的自由运动和受迫运动两个数值仿真算例验证扰动观测器的有效性,结果表明设计的扰动观测器估值与真实值基本一致。研究为后续包含扰动补偿的控制器设计奠定了基础。To improve the control efficiency,the design of nonlinear disturbance observer（NDO）was studied to estimate the influence of the flexible appendage on the translational and rotational motions of the spacecraft＇s main body for free-floating flexible spacecrafts with the coupling between the translational and rotational motion of the spacecraft and the vibration of the flexible appendage in this paper.The floating spacecraft was simplified as free hub beam（FHB）.The dynamic equations of the system were established by floating coordinate system.The flexible appendage was discrete for computation convenience by assumed mode method.The all terms related with nonobserved state were treated as the equivalent disturbance,and it was assumed that they were slow changed and bound constrained.The observer was designed,which had asymptotic convergence and robustness because the disturbance of the flexible appendage on the position and attitude of the spacecraft was in consideration.The Lyapunov function was given to prove the convergence of the observer designed theoretically.Two numerical simulations which were free motion without force input and forced motion were computed to verify the effectiveness of the observer designed.The results showed that the estimation by the observer designed was well agreed with the true value.The study is valuable for latter controller design including disturbance compensation.

关 键 词：自由漂浮 柔性航天器 扰动观测器 LYAPUNOV稳定性 中心刚体 柔性梁 扰动估计 渐近收敛 

分 类 号：V448.2[航空宇航科学与技术—飞行器设计]