The Impact Dynamics Analysis And Stabilization Control Of Floating Base Single-arm And Dual-arm Space Robots Capturing A Target

As the development of astronautics technology, more and more spacecraft are sent into space, and the astronautics operation missions for fault spacecraft capturing and recycling are becoming heavier. In the extremely harsh space environment, the using of space robots for assisting or replacing astronauts in space on orbit capture operation has good prospects. In this paper, the impact dynamics and stabilization control for three different structure floating base space robots are studied.According to the multi-body dynamics, the dynamics model of three different structure space robots (single rigid arm, single flexible arm and dual-arm) are derived respectively; base on the dynamics model, the impact effect for three different structure space robots during the target capture is analyzed by momentum theorem; and then, the combination system dynamics model of space robots and target after capture is further derived, the above impact effect will cause the unstable motion of combination system.Firstly, for the relatively simple structure single rigid arm space robots, and considering different situations, different control algorithms are proposed for the unstable combination system stabilization control:an adaptive control algorithm is proposed when the parameters of target are unknown, the effect for stabilization control will be overcome by real time online parameters adaptive calculation and adjustment; a robust control algorithm is proposed when the range of the target parameters are known, but the exact value is uncertain, the control algorithm will reduce the control calculation for improve the response speed of controller; base on the above control algorithms, a new robust and adaptive compound control algorithm is proposed for stabilization control when the target parameters is unknown and space robots parameters is uncertain; a sliding mode control algorithm base on disturbance observer is proposed for stabilization control which will eliminate the unknown disturbance and the sliding mode tremble problem, it will improve the robustness of the control algorithm; a neural network control algorithm is proposed for stabilization control which doesn’t depend on the combination system dynamics, this control algorithm has broader application.Then, for the single flexible arm space robots and under different situation, different control algorithms are proposed for the stabilization control, and they need further consider elastic vibration suppression control for the flexible link:the linear feedback, adaptive and robust control algorithm are respectively proposed for stabilization control when the target parameters are known, unknown and uncertain, and the above control algorithms will all need to add vibration suppression control algorithms at the same time:considering the vibration suppression control will affect the stabilization control, the combination system dynamics model is decomposed into slow subsystem and fast subsystem by singular perturbation method, and a neural network control algorithm is proposed for the stabilization control of slow subsystem, a linear quadratic optimal control algorithm is proposed for the vibration suppression control of fast subsystem, and the latter control algorithm will not affect the stability of the former control algorithm; a neural network control algorithm base on the hybrid trajectory will achieve the stabilization and vibration suppression control by a control algorithm at the same time.For the dual-arm space robots which the structure is more complex than the above, the space robots and target will become a close chain combination system after the impact, and different stabilization control algorithms are proposed under different situation:a linear feedback control adds internal force control is proposed for the force/position coordinate stabilization control; base on the above control algorithm, and adds robustness compensation term, it will become a new robust control algorithm which will overcome the effect when the dynamics model is unknown; a sliding mode control algorithm base on disturbance observer is spread for stabilization control of the close chain combination system, it will overcome the unknown disturbance and eliminate the sliding mode tremble.Finally, the stability of the above control algorithm is proved, and computer numerical simulation is applied for verifying effectiveness of motion stabilization control.