Study On Coordinated Control And Its On-Ground Experiment For Space Robot

With the rapid development of science and technology in space exploration, the space robotics is now regarded as one of the most important space technologies. To perform the various tasks, the space robot needs to work under different conditions, such as free-flying and free-floating. The thesis focuses on how to fulfill the scheduled mission with less fuel and energy consumption. Taking 6-DOF single-arm space robot as the object, the thesis deduces the kinematic and dynamic models, analyses the effects of uncertainties and proposes an improved robust compound adaptive control method. To save energy and solve the problem of uncertainty, a coordinate control between motion of manipulator and satellite orientation is introduced, whose stability is proved by Lyapnove function. The proposed method is also validated on space robotic simulation system with electric emulator modules.First, the recent foreign and domestic space robotic projects and related on-ground experimental testbeds are summarized, while the fundamental theory and control methods for space robot are evaluated as well. The kinematic and dynamic models for free-flying and free-floating space robots are deduced respectively.Second, the effect of dynamic parameters uncertainty is analyzed. To resolve the uncertainty problem, the improved robust compound adaptive control method is adopted and verified with a 2-DOF space robot model. The proposed method can avoid the difficult parameter linearization, which is the bottleneck of most traditional adaptive control methods.Then, the importance of fuel saving is introduced, a coordinate control strategy for single-arm space robot is developed, including satellite orientation control module, motion programming module and manipulator control module. The frame of the coordinate control system, as well as the schematic diagram, is presented. The method solves the problems of reaction torques and dynamic uncertainties, which ensures the stable movement of the space robotic system without the active attitude control.Last, the details of electric simulation system are introduced. The proposed coordinate control strategy is applied in the emulator module. The performed control experiment shows that the method can gain the design goal, which is to stably control the whole space robot system.