Development Of Multi-axis Motion Control System Based On Flexible Capture Manipulator

With the rapid development of space technology and the improvement of aircraft performance,the space on-orbit capture technology and the space on-orbit service technology are more and more important in aero-space industry.In the process of docking with the other spacecraft,the space on-orbit capture technology is directly related to docking success.At the moment of contact with the target during the on-orbit capture,the impact of the manipulator is very strong.Having no energy absorbing elements like dampers,the traditional rigid arm is easy to cause the instability of the base under the impact of the target object.The multi-axis motion control system based on the flexible capture manipulator is studied in this paper.This paper is supported by NSFC[51305039].Specific research work is as follows:Firstly,aiming at the structure and working principle of Brushless DC motor,the mathematical model of Brushless DC motor is established,which contains voltage-balanced equation,motor output torque equation and motor motion equation.And make the main simulation models in Matlab,such as back electromotive force module,speed module,torque module,BLDC module and voltage inverter module.A double loop PID control method is employed in the simulation.By comparing the simulation curve and the theoretical curve,the accuracy of the model and the effectiveness of the control method are verified.Secondly,The Kane dynamic model of the manipulator with 6N degrees of freedom is established in this paper.Aiming at solving the problem of the expected damping force of controllable damping element in the manipulator,a particle swarm optimization algorithm with time varying target value is proposed,and the simulation results are verified in Matlab.Results show that the algorithm is applied to solve joints optimal damping force in the finite time convergence of manipulator vibration displacement and the vibration force/torque.The stability of the whole system of the manipulator and the base is guaranteed.Then,based on the FPGA,the hardware module of the manipulator motion control system is designed,and the software based on C++ is realized.The main modules of the hardware design are analyzed,such as motion control unit,communication,motor drive and power supply conversion.The selection of modules and the design of interface circuit are completed.Software programming is implemented for CAN communication,motor control and drive control module.Finally,on the ground air bearing test platform,the positioning and speed regulation experiment,the experiment modeling and damping performance test of MR damper,the rigid motion control experiment of the manipulator and the flexible capture and impact test are carried out.The effectiveness of the control method is verified by physical prototype experiment.