Research On Trajectory Tracking Control For Floating Base Manipulator

With the innovation and development of intelligent robots,the robots have been turned to applyed in space environment from ground environment.Space robots can be used for maintenance and satellite docking in space station,they are also available for microgravity and high radiation experiment in space station.So countries are paying close attention to the projects about space robots recently.Space manipulators were capable of helping astronauts to do auxiliary operation in gravity-free native environment.Nowadays,space projects have been one of the hotspot contents for scholars.The floating space mechanical arm can complete the task of grabbing the satellite and replacing the battery in the space station.Therefore,the trajectory of the robot arm is also the focus of research in various countries.This thesis is mainly analyzing the problems in trajectory tracking and disturbance inhibiting ability of space manipulators based on the free-floating two-link manipulators.The main research contents are as follows:First of all,this thesis is analyzed research status about control algorithm of space manipulators.The disadvantages and improvements of control strategy for space manipulators and force analysis of two-link manipulators are put forward in this thesis.Kinetic equation and kinematics formulation are solved with Lagrange equation in terms of the law of conservation of momentum,and then the mathematical model for space manipulators is constructed.Secondly,two advanced algorithms used to model and Control law are solved.In order to reduce the error of trajectory tracking under the microgravity environment,an adaptive backsteppting sliding mode method is proposed to control the system.This algorithm based on the error back-calculation and it sets the manipulator as a fully automated operation model.The calculation is small and the parameters can be adjusted in real time to make the system more stable.On the basis of the above,the second algorithm sets the high-order sliding mode disturbance observer to control the system,which enables the system to track accurately and enhance the robustness of the system.The stability of the system is verified by the Lyapunov method.Finally,the control law is combined with the mathematical model of the observer to reduse the disturbance of the manipulator in the microgravity environment.Again,The two algorithms are simulated in the microgravity environment by MATLAB.The backsteppting adaptive sliding mode algorithm system can perform real-time tuning to reduce the system working errors,and also reduce the system disturbance,and it can making the system trajectory tracking more accurate.Setting the high-order sliding mode observer allows the system to observe the interference curve in real time and it correct the disturbance curve at the same time.The system can be applied to more complex curve trajectories,contrast and draw conclusions with ordinary sliding mode control by the same physical model and experimental environment.Experiments show that the algorithm proposed in this thesis is more effective.Initial hardware choices and circuit design for manipulator are made based on the control strategy to analyze hardware and software model.It would make the control process more illustrative.Lastly,the work done in the full text is summarized and analyzed,the post work is expected to forecasted and arranged.