Study Of Space Manipulator Control For Micro-satellite On-orbit Servicing

With the rapidly development of space technology,there are more and more complex tasks in space for human beings.Space robot is one of the most important means for various kinds of space missions,such as orbit control,on-orbit attack and defense,exploration of outer space and planetary resources.Space robot refers to a manipulator mounted on spacecraft body,which can realize station maintenance,failure satellite recovery,mineral collection and so on in space,instead of astronauts.In this paper,the kinematics and dynamics modeling and control of the space manipulator for micro-satellite on-orbit servicing are studied.Firstly,the motor algebra is used to set up the kinematics model of the single-arm 5-DOF space robot combined with the virtual manipulator,the position and attitude relation between the end effector coordinate and the coordinate is deduced to get the kinematics equation.Then an algorithm for solving the inverse kinematics problem of manipulator in the framework of motor algebra is presented and the algorithm is validated by numerical simulation.The results show that the motor algebra is effective and has high accuracy in solving the manipulator kinematics problem.Then,the generalized Jacobi matrix of planar dual-arm robot with n degrees of freedom is derived,resolved motion rate control is used for computer simulation of the motion of the robotic.The general dynamic equation and the dynamic equation of free floating state are derived.Secondly,the trajectory planning of joint space robot is carried out using polynomial equation method.The joint variables are regarded as a function of time,and the velocity and acceleration of the function are derived to obtain the joint trajectory.Then,the attitude constrained generalized Jacobi matrix is derived for the planar dual-arm space robot.The trajectory planning of planar arms is carried out by using the linear velocity parameterization method based on the attitude constrained generalized Jacobian matrix,and the motion control simulation of the planar dual-arm robot is carried out.Based on the trajectory planning of single-arm space robot,the trajectory tracking control method of single-arm 5-DOF space robot is designed.The model of single-arm space robot is precisely linearized by Lie derivative,and the optimal controller is used to simulate the trajectory tracking control of the space robot.Finally,the dynamic model of the space robot and the controller are further verified.Based on the dynamic simulation environment of ADAMS virtual prototype,combined with three-dimensional modeling software Pro/E,Single-arm 5-DOF space robot system virtual prototyping is established.And ADAMS-MATLAB co-simulation platform is established by means of ADAMS and MATLAB data interaction interface for completing the virtual prototype of space robot system simulation experiment.The results of the virtual prototype simulation experiment are in good agreement with the numerical simulation results of self programming,which proves the correctness of the dynamic model of the space robot system and the validity of the designed controller.