Research On Kinematic Calibration And Trajectory Planning Method Of Hyper-redundant Robot

In this paper,a 21 DOF cable driven hyper-redundant robot is developed,the multi-level relationship of kinematics is analyzed,the kinematics model is established,the parameter errors in the kinematics model are calibrated,the related trajectory planning technology is studied,and the experimental prototype platform of cable driven hyper-redundant robot is built to verify the kinematics performance of the designed hyper-redundant robot and the correctness of the proposed trajectory planning algorithm.According to the operation task requirements in narrow environment,the functional and performance requirements of hyper-redundant robot are determined.A 21-DOF hyperredundant robot is designed based on the scheme of short link,universal joint and cable driving.The robot is composed of a horizontal slide,a serpentine arm and a driving module.The horizontal slide provides the linear motion ability for the hyper-redundant robot;The serpentine arm is composed of 10 modular joints with 2 degrees of freedom in series and has the movement capacity of 20 degrees of freedom.The total length of the serpentine arm is 1482 mm,the diameter of the connecting rod is 53 mm,and the working range is 1.3m in XY direction and3.5m in Z direction;The drive module consists of 30 motor lead screw modules.Each motor lead screw module is responsible for controlling one drive cable.Through the linear movement of the motor,the control of the pitch and yaw direction movement of the serpentine arm is realized.For the designed hyper-redundant robot,the kinematic relationships between cable space and joint space,joint space and task space are analyzed,and the parameter errors of kinematic model are calibrated.The forward kinematics model of the hyper-redundant robot is established by using the improved D-H parameter method.According to the coordinate homogeneous transformation relationship,the multi-level mapping relationship of the robot in cable driving space,joint space and task space is established.Based on the robot kinematics model,combined with the differential mapping relationship between D-H parameters and end position,the robot kinematics parameter error model is established and the robot kinematics parameter error is calibrated.The trajectory planning method of hyper-redundant robot in narrow environment is studied,and an efficient inverse solution method and Obstacle Avoidance Trajectory Planning Method of hyper-redundant robot with compliant arm are proposed.The initial solution is obtained by using the idea of gradient descent method.The solution space of the algorithm is limited to the narrow area near the initial solution.An optimization model is established based on particle swarm optimization algorithm for iterative optimization.Simulation experiments show that the proposed method is more than 60% higher than decreasing weight PSO and random weight PSO in solving accuracy and arm flexibility,and more than 90% higher than Jacobi pseudo inverse method in solving efficiency.At the same time,aiming at the problem of Obstacle Avoidance Trajectory Planning in narrow obstacle environment,the Obstacle Avoidance Trajectory Planning Based on Jacobian pseudo inverse method is studied.The experimental prototype platform of hyper-redundant robot is built,and the robot control system is developed based on Twin CAT system.The motion accuracy experiment,kinematics calibration experiment,kinematics inverse solution experiment and motion planning algorithm verification experiment are carried out to verify the good spatial motion ability of the designed hyper-redundant robot and the effectiveness of the proposed calibration algorithm and trajectory planning algorithm.