针对空间运输舱具有较大的速度和惯量,在对运输舱的操作过程中存在着冲击和碰撞,严重的时候会影响系统的安全的问题,研制中国大型空间末端执行器,设计大容差柔性钢丝绳捕获机构和基于滚珠丝杠螺旋传动副的拖动机构,并且对其捕获传感器系统进行设计。根据末端执行器机构特点和工作原理,提出基于Loop/Contact控制模型的捕获控制策略,有效地减小了操作对系统的冲击。建立空间微重力环境下末端执行器系统和运输舱系统的动力学模型,推导大型末端执行器在轨操作运输舱的动力学方程。计算机仿真试验证明,捕获过程中捕获力较传统方式降低50%,试验证明捕获力小于700 N,二者验证了末端执行器的实用性和控制策略的可行性,对提高大型空间末端执行器的工作稳定性具有重要意义。
While manipulating a huge transfer vehicle cargo(TVC) in space,shock and impact are inevitable due to its high inertia and velocity and even can influence the safety of the whole system.The Chinese large-scale space end-effector(EER) is developed.Large-tolerance flexible steel cables capture mechanism and the retracting mechanism based on ball screw assembly are designed.The capture sensory system is also presented.According to the characteristics of EER's mechanism and its working principle,the capture strategy based on Loop/Contact model is proposed.The control strategy decreases the impact to the system dramatically.The dynamic models of EER and TVC under space zero-gravity environment are established.The dynamic equations of EER manipulating TVC in orbit are derived.Computer simulations show that the capture force reduces up to 50% in comparison with that of the traditional method.Experiments demonstrate the capture force is lower than 700 N.Both verify the innovation of the EER mechanism and the feasibility of the control strategy,which has important meaning to EER working stability.