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 configuration results in lower stiffness of the system. In order to satisfy higher machinery stiffness required by the control 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 stiffness 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 optimumbearing preload.