Pneumatic Attitude Control of the Air Bearing Tesbed to Simulate the Three Axis Free Tumbling Motion of an Uncooperative Target

With the rapid development of the exploration of outer space, more and more mission related spacecraft was abandoned in space and became space debris. Space debris, such as the upper stages and expired satellites, pose great threaten to the functioning satellite on orbit. It is urgently required to remove the space debris from space to grave orbit or decrease its orbit and reentry into atmosphere. The first step to remove the space debris is capture or detumble. An important characteristic of the space debris is the tumbling motion result from perturbations, including solar pressure, residual momentum before expiration. Therefore, the ground simulation of the three dimensional tumbling motion of space debris is required for the successful verification of various on orbit capture and detumble technologies. The tumbling motion of an uncooperative target can be simulated by attaching to a robotic arm, while this method might have singularity problem at several given position. Consequently, three dimensional spherical air bearing system is used for the simulation of the tumbling motion of space debris. An attitude control algorithm is designed to driven the testbed to a tumbling state and provide the initial status for the on orbit capture and remove mission. The attitude control algorithm is realized by the pneumatic actuator on the testbed, which including air tank, electromagnetic valve and pulse width pulse frequency (PWPF) regulator. The simulation results show the control algorithm can drive the testbed to the required tumbling status in a reasonable time.