Design And Experiment Of Gravity Compensation Equipment

The fast development of aerospace industry necessitates a high quality requirement of the spacecraft ground test device.As a core section of the spacecraft ground test device,gravity compensate rig creates a moon-surface-like microgravity condition for the simulation tests on earth.In this project,the feasible programs on the gravity compensate rig for mimicking moon surface microgravity condition were studied.By analyzing the feasibility of different constant tension suspension scheme,a suitable program was determined.The mechanical structure of this rig(including the ben ch support system,suspension system and measuring system)was designed such that an accurate constant tension suspension can be created,3 m/s escaping velocity can be satisfied,and that the error of gravity compensation can be minimized below ±6%.By designing the separation device,an escaping velocity ranging from 0 to 3 m/s is guaranteed;meanwhile,suitable torque and rotational speed,sufficient lifting force and passing mass centre suspension can be achieved within 10 ms.To enhance the system control efficiency,separation control system and gravity compensate control system were constructed separately.Basic PID control algorithm was applied for the separation system and self-adapt fuzzy PID algorithm for gravity compensate system.Mathematical modeling and simulation analysis were performed using Simulink,and it was verified that the separation system is capable to trace the angular velocity of the target accurately.The vertical motion of the object was considered as the external position noise,and this noise can be minimized via the self-adapt fuzzy PID control algorithm,so that the simulation accuracy satisfies the standard requirement.To verify the system quality,running in tests were carried out for this gravity compensate rig,covering velocity separation test(to check the designed velocity of the object);the error experiment of static equilibrium(to check the gravity compensation accuracy).The test results showed that all the requirements specified above can be satisfied for this gravity compensate rig.