Research On Motion Planning And Torque Optimization For A Redundant Free-floating Space Robot

With the development of space technology, more and more science research and exploration of the outer space would be taken on by mankind. But due to bad space environment, high cost and risk of sending people to space, the requirements for space robots are brought up. Free-floating space robots are much concerned since they consume little fuel. This paper is to deal with motion planning and torque optimization of a free-floating redundant space robotic system and to carry on some theory research and discussion full of great application value.Firstly the kinematics properties of this system are detailed, and then the whole system kinematics model is built. Combining the redundancy of space manipulator, the system attitude stabilization motion planning is accomplished by the resolved motion rate control method. Successively the system singularity avoidance motion planning is accomplished through the utilization of the self-motion based on the null space. After that, dynamic equations of a free-floating redundant space robot are established through the utilization of the method of multi-body dynamics. Then the system dynamics control is accomplished by the computed torque method. At last, two local optimization approaches based on null-space method and minimal joint torque method are applied to implement the joint torque optimization control, considering the instability of the local optimization approach, a global optimization approach based on particle swarm algorithm is proposed, and then we deeply analyze advantage and disadvantage of the three algorithms. The application of optimization approaches can reduce the energy consumption of this system on a certain extent and has a great practical significance.The paper presents in-depth research on motion planning and joint torque optimization of this space robotic system. Attitude stabilization, singularity avoidance and joint torque optimization on this system are implemented. All the research work done here will surely benefit to the further research and even to the application of this space robotic technology in the future.