Research On Space Manipulator Trajectory Optimization Concerning Dynamic Propoties

In recent years, the quantity of the space mission is gradually increasing and the space missions are becoming more complex. Under the premise of the successful completion of the space mission, more performance, such as the efficiency of undertaking a task and the length of the service period, is request to be better. Trajectory optimization is an important way to increase the performance.Therefore this thesis will focus on resolving on trajectory optimization, which include space manipulator task planning, trajectory optimization under multi-constraints and multi-objective, and space manipulator online path planning considering dynamic properties. Numerical simulation and visual simulation is performed to verify the feasibility of the corresponding method. The study includes the following aspects:Firstly, a task planning method based on basic motion assumed is proposed. Space manipulator tasks are analyzed, in-orbit operation of the space manipulator tasks grouped into four typical types. Furthermore, through the introduction of the "basic motion" concept, the task of space manipulator model is simplified, the mission planning method based on basic motion assumed is put forward. This method has some versatility, able to obtain the relevant minimum cost robotic action sequences. Finally, the space manipulator with seven degrees of freedom for the study, carried out using the above method mission planning, and verify the correctness of the algorithm.Secondly, the typical constraints and optimization criteria of space manipulator are analyzed. For the space of seven DOF manipulator trajectory tracking tasks, using NSGA-II multi-objective optimization algorithm, completed a space manipulator ends maximum speed and maximum acceleration of decision variables, time, energy optimal target trajectory optimization. The method to obtain the optimal solution set Pareto for policy-makers to further screening. Ultimately validated by numerical simulation of the method.Finally, the joint torque may overrun when performing a task, an online path planning method is proposed, which can adjust the joint torque. The dynamic model, which introduces the time-scaled factor, is built. This method can avoid the complex computing through dynamics of joint torque model, significantly increasing the computational efficiency of the joint torques. Therefore, when the joint torque overrun by changing Manipulator parameters in real time to ensure the successful completion of in-orbit mission, thus achieving an efficient and reliable on-line control of the manipulator, ultimately validated by numerical simulation of the method.