无扰载荷航天器相对运动动力学建模

Dynamic Modeling of Relative Motion for Disturbance-Free-Payload Spacecraft

为满足无扰载荷(DFP)航天器中非接触式作动器对有效载荷模块(PM)与支持模块(SM)之间相对运动的要求,本文建立了PM与SM之间的六自由度相对运动动力学模型。考虑立方构型DFP接口,分析了作用于PM与SM的力和力矩。考虑DFP航天器相对运动控制的特殊性,建立了SM相对PM的相对姿态动力学模型和PM相对SM的相对平动动力学模型,然后采用比例微分(PD)控制方法设计了DFP航天器的控制系统。数值仿真结果表明,定向状态或姿态机动过程PM与SM六自由度相对运动均满足非接触式作动器作用范围的要求,既可保证PM与SM无机械接触,又可实现对PM精确定向和姿态机动,说明六自由度相对运动动力学建模对研究DFP航天器具有重要意义。

In the disturbance-free-payload （DFP） spacecraft, the relative motion between the payload-module （PM） and support-module （SM） should be researched to meet the requirements of the non-contact actuators. In this paper, the six-degrees-of-freedom relative dynamics model between the PM and SM is established. Focusing on the DFP spacecraft with a hexapod cubic DFP interface, the forces and torques acting on the PM and SM are analyzed. Then, the rotational dynamic model of the SM relative to the PM and the translational dynamics model of the PM relative to the SM are established considering the characteristics of the relative motion between the PM and SM. Furthermore, the control system of the DFP spacecraft is designed based on the proportional differential （PD） control. The simulation results show that the relative motion of the DFP spacecraft can satisfy the requirement of the non-contact actuators, whether it is pointing or maneuvering. This illustrates that the non-contact actuators tan separate the PM and SM and control the PM simultaneously, and reveals the significance of the dynamic modeling of the relative motion for investigating the DFP spacecraft.