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目前对空间组合体中可变形桁架(Variable Geometry Truss,VGT)运动规划问题的研究集中在各级均为单自由度或离散二状态等简单结构的情形,未解决所有可调长度杆都能够自由运动的复杂结构运动规划问题。文章根据组合体的几何关系,建立了递推位姿运动学模型,再由自由漂浮系统动量守恒,建立了微分运动学模型。给出了单级VGT变化序列与运动时间分开设计的两步运动规划方法,并在优化目标中加入能量项,给出了多级冗余VGT的运动规划方法。最后通过仿真验证了算法的有效性,在算例中优化指标为J=0.879 8,该方法对以VGT作为空间操作机构的组合体研究具有一定工程指导意义。
At present, the research on the motion planning of VGT in space assembly is focused on the simple structure of single-degree-of-freedom or discrete-second-state at all levels. It can not be solved that all adjustable- Sports complex structure movement planning problem. According to the geometrical relationship of the assembly, a recursive kinematics model is established, and then the differential kinematics model is established by the momentum conservation of the free-floating system. A two-step motion programming method is proposed to design a single VGT variation sequence separately from the motion time. The energy term is added to the optimization objective and the motion planning method of multi-level redundant VGT is given. Finally, the effectiveness of the algorithm is verified by simulation. The optimization index in the example is J = 0.879 8. This method has certain engineering significance for the study of the combination of VGT as a space operating mechanism.