对失效卫星特征点的自适应位姿跟踪控制

为满足对失效卫星上某个特征点位置悬停的同时使追踪星上敏感器指向该特征点，展开了对失效卫星特征点与追踪星间相对动力学建模与控制的研究。在追踪星本体坐标系下建立了六自由度相对位姿动力学模型，并结合失效卫星上特征点的运动规律，给出追踪星的期望跟踪位置和期望跟踪姿态。考虑到追踪星质量、转动惯量、系统所受扰动力、扰动力矩及失效卫星转动惯量的不确定性，设计了复合自适应位姿跟踪控制律，并通过Lyapunov法证明了闭环系统稳定性。对输出受限情况,采取设计控制参数调节过程及输出限幅措施。在仿真条件下，系统在自适应控制律下能够以位置误差约1cm、姿态误差约0.01°完成位姿跟踪任务；增大不确定参数偏差后，位置跟踪误差增至约7cm，姿态误差增至约0.1°；对控制参数进行调节后，可在不影响跟踪精度的条件下在指定范围内限制输出幅值，将幅值限制在指定范围内，并减小控制所需冲量的9%和冲量矩的30%。

Adaptive control of coupled position and attitude fortracking characteristic point of disabled satellite

In order to realize the hovering and the attitude directing to characteristic point on disabled satellite at the same time, the relative dynamics and control between the characteristic point and the chaser were researched. The coupled position and attitude dynamic model was built under the chaser’s body frame. Combined with the kinematics of characteristic point, specific point, the expected position and attitude of the chaser were derived. considering the chaser’s mass, moment of inertia uncertainty, system’s disturbing force and disturbing moment uncertainty, and the moment of inertia uncertainty of the disabled satellite, an adaptive control law was designed, and the closed-loop system was proved to be stable through Lyapunov method. If there were constraints for the output, the process for adjusting the control parameters was designed and the output values were limited. The numerical simulation shows that the system can complete the tracking mission with position error1cm and attitude error 0.01° under the designed control law With the increasing of uncertain parameter’s deviations, the position error is raised to 7cm while the attitude error is raised to 0.1°. To adjust the control parameter and limit the output’s value, the control force and control moment can be restrained in the expected range while the tracking accuracy does not change, and the control required impulse can be reduced 9% while the required impulse moment can be reduced 30%.