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航天器交会对接地面模拟系统用于研究航天器交会对接过程的动力学、导航与控制等方面的相关问题。模拟器通过气浮轴承悬浮在大理石平台上来模拟太空的无摩擦微重力环境。通常情况下要保证大理石平台足够水平,由于实际平台不可能完全水平,模拟器的重力分量会使模拟器产生下滑现象,这种现象对大型地面模拟器设备尤为严重。针对模拟器的逼近过程设计了轨迹规划。为了减小测量信号噪声的影响,采用跟踪微分器(TD)对整个逼近过程中的测量信号进行滤波。针对逼近过程中模拟器存在下滑力等干扰问题设计控制器,通过扩张状态观测器(ESO)实时估计干扰量,进而对干扰量进行补偿。对模拟器冷喷气推力系统制定了推力器分配策略,采用脉冲宽度调制(PWM)技术实现对推力的近似等效。提出的控制方法应用于航天器交会对接地面模拟系统,实验结果表明所提出的控制方法能有效消除下滑力等干扰的影响。
Spacecraft rendezvous and docking ground simulation system is used to study the dynamics, navigation and control aspects of the spacecraft rendezvous and docking process. The simulator floats on a marble platform with air bearing to simulate the frictionless micro-gravity environment of space. Under normal circumstances to ensure that marble platform level enough, due to the actual platform can not be completely horizontal, the simulator gravity component will make the simulator produce a decline phenomenon, this phenomenon is particularly serious for large ground simulator equipment. The trajectory planning is designed for the approximation process of simulator. In order to reduce the influence of the noise of the measurement signal, a tracking differentiator (TD) is used to filter the measurement signal in the entire approximation process. Aiming at the disturbance of the simulator such as the sliding force in the process of approximation, a controller is designed to estimate the interference in real time through the extended state observer (ESO) to compensate for the interference. The thruster allocation strategy is developed for the simulator cold jet thrust system and the approximate equivalent of thrust is implemented using pulse width modulation (PWM) technology. The proposed control method is applied to the spacecraft rendezvous and docking simulation system. The experimental results show that the proposed control method can effectively eliminate the influence of the sliding force and other disturbances.