Research On Key Technologies Of New Hyper-redundant Space Manipulator

Affected by the launch load and volume,the super-large-diameter space telescope needs to be assembled in space.This assembly task has high requirements on accuracy,response speed,and dexterity.Traditional space manipulators are large in size and have low obstacle avoidance capabilities,and they are not flexible when performing tasks in narrow spaces or complex environments.Therefore,the development of new hyperredundant dexterous space manipulators is essential for on-orbit assembly.This paper introduces the first generation of self-designed hyper-redundant space manipulator,including the structure design of the joint,the working principle of the arm,electric control system and the performance test.It also demonstrates the structural design of the second generation self-designed space dexterous arm and the finite element analysis of the shell under force.By comparing and analyzing with the first generation arm,the improvements are clearly pointed out.The reachable and dexterous workspace of the arm are calculated.For the manipulator with many degrees of freedom(such as a snake robot),the kinematics analysis based on the spinal curve is given.For the nine-degree-of-freedom manipulator,kinematic modeling based on DH parameters is proposed.In order to better realize the trajectory planning and obstacle avoidance of the arm,the Bi-RRT algorithm is improved.A co-simulation system was built,and obstacle avoidance experiments were conducted based on the simulation results.The experimental results not only show the effectiveness of the obstacle avoidance algorithm,but also prove that the arm has strong obstacle avoidance ability and dexterity.The dynamic equations of the manipulator based on the static base are analyzed,including the kinetic and potential energy of the multi-body system,Lagrange dynamic equations,and local parameterization method.The dynamics analysis of the freefloating flexible manipulator is carried out.The analysis method is based on the assumed modes method and linear elasticity assumption,and considers the position and attitude constraint equations,so as to obtain the multi-body dynamic equations of the space manipulator.In order to improve the motion performance of the space manipulator,an improved intelligent control algorithm is proposed.They include predictive fuzzy control based on error analysis model and command filter,and neural network vibration suppression control based on dynamics model and disturbance observer.In addition,three experiments were designed to verify the effectiveness of the control strategy.The experiments are adaptive motion after the manipulator is stressed,writing motion of the end effector,and vibration suppression of the arm.The experimental results show that the improved method can not only make the manipulator move more smoothly,but also reduce the dynamic coupling between the joints,thereby suppressing the vibration of the arm.