Research On Collision Detection Technology Of Space Manipulator

With the development of space exploration,space manipulator plays an important role as an operating tool.In the complex and unknown space domain,the space manipulator can help the human to complete many high-risk tasks,but also can improve the work efficiency.Because space manipulator has many advantages,the research investment of space manipulator is increasing gradually.In order to ensure the safe and reliable work of the space station system and the space manipulator,collision detection technology of space manipulator is studied.First,the basic research of space manipulator is carried out.The forward kinematics model of the space manipulator is established based on the configuration of the space manipulator and the change of joint Angle to obtain the position and attitude of the end of the space manipulator.The jacobian matrix is solved at the velocity level by using the cross product method.The inverse kinematics of the space manipulator was analyzed by using the improved pseudo-inverse method and the projection gradient method,and the simulation model was established in Simulink module for verification.Secondly,the orbital collision detection of the space manipulator based on sphere and capsule is studied.Aiming at the in-orbit limited resource constraint and real-time requirement of the space manipulator embedded system,the envelop model of the space manipulator and space station is established,and a fast collision detection method of the space manipulator in orbit is proposed based on the intersection test algorithm of sphere and capsule.Based on the kinematics of the space manipulator,the position of the collision model was updated,and the collision detection pairs were optimized for different situations.The program was written to test the real-time requirements.In this paper,an index of object shape approximation is defined,and the precision of the envelopment model established by the space manipulator and space station is analyzed.Then,the high precision collision detection of the space manipulator based on ball sweeping convex body is studied.For the robot arm and space station,the model of ball sweeping convex body is established to ensure high precision.Based on the kinematic update of the collision model location of the space manipulator,the collision detection pair was constructed and optimized.The GJK algorithm was used to calculate the shortest distance of each collision pair,so as to prepare for the subsequent simulation.Finally,the simulation of space manipulator collision detection is carried out.Open Inventor and Visual Studio were used to build the simulation software environment,and the space manipulator's collision was analyzed.The on-orbit collision detection of space manipulator based on sphere and capsule body enclosure box and the ground collision detection of space manipulator based on GJK algorithm were simulated andverified.And for the delivery plate handling task,planning the relevant path for motion simulation.