Research On 6-DOF Microgravity Simulation Platform

With the rapid development of the aerospace industry, space exploration has become more and more frequent, and tasks are becoming increasingly complex. The focus of space technology has been transferred to some new areas, such as spacecraft maintenance, debris cleaning, space docking and satellite capturing, which is highly valued by many spacefaring powers. Due to the special nature of space operations, a micro-gravity environment in the orbit must be emulated on ground before launching the aerospace equipment, which is the security of the space missions. Therefore, it is of great value of research and application to develop a laboratory test bed to emulate the kinematic and dynamic nature in micro–gravity.Based on this, this paper designed a micro-gravity simulator consisting of a Stewart platform with six parallel-mode dual-drive actuators which provide six degrees of freedom and accomplished the integrated design of the dual-drive configuration of the leg. For the simulator has multiple design parameters and performance indicators, the paper proposed effective workspace, global dexterity and global force transmission performance as the optimal objective function, and then used two-stage multi-objective method to accomplish the multi-parameter, multi-objective optimization of the micro-gravity simulation platform. Kinematics was analyzed and a highly efficient inverse dynamic model was established by using Kane method, numerical calculation of which was calculated then.After that, the stiffness property of the pneumatic actuator and the dynamic characteristics of cylinder pressure were analyzed. The servo control of the chamber pressure was carried by using the fuzzy PID control, which is simulated afterwards. On this basis, this paper accomplished the collaborative simulation of one single leg from the motor and cylinder, and then analyzed force of the motor and cylinder, which verified the effectiveness of the synchronous drive method.