空间臂式补偿机构轴承预紧力与系统刚度关系分析

为了补偿空间光学望远镜在轨跟踪目标过程中受空间各种因素影响而导致的光学系统视轴和目标之间产生的相对移动和旋转(即指向偏差和指向振荡),设计由臂式补偿机构控制望远镜补偿与目标的相对运动.但由于臂式补偿机构的尺寸和质量严格限制在一定范围内,且望远镜尺寸很大,质量达3 000 kg,这种结构形式导致系统刚度很低.为了满足控制系统提出的结构高刚度要求,在系统结构形式确定的情况下,分析施加轴承预紧力提高系统刚度的可行性.分析了轴承预紧力、轴承刚度和系统刚度之间的关系,获得了轴承预紧力与系统固有频率的关系.分析证明在系统结构形式确定的情况下,施加合适的轴承预紧力,可以提高系统的刚度,同时为轴承最佳预紧力的确定提供了一个有效的方法.

Analysis on the relationship between bearing preload of spatial arm compensation mechanism and system stiffness

When the spatial telescope tracks the target on the orbit, move and rotation will occurr between the visual axis of the telescope and target（ namely pointing deviation and oscillation） due to all kinds of factors in space. In order to compensate above errors, the arm compensation mechanism is designed to compensate the errors between the visual axis and the target. Because the size and weight of the arm compensation mechanism are restricted severely, and the size of the telescope is huge and its weight is more than 3 000 kg, this configu- ration results in lower stiffness of the system. In order to satisfy higher machinery stiffness required by the con- trol system, the feasibility is analyzed to improve system stiffness through forcing preload on bearing after the system configuration is confirmed. This paper studies on the relationship among bearing preload, bearing stiff- ness and system stiffness, and the relationship curve between bearing preload and system natural frequency is obtained. The analysis proves that forcing an appropriate preload to bearing can improve system stiffness on the condition that the system configuration is confirmed, and it is also an effective method to confirm the optimum bearing preload.