Research On Motion Planning Method Of Snake Robot

The snake robot is a kind of bionic robot with hyper redundancy,which has a rigid mechanical arm and can withstand higher loads compared with the soft body snake robot;its hyper-redundancy makes it more flexible and more adaptable to the environment compared with the traditional rigid body robot.With the advancement of technology and science,the application scenarios of hyper-redundant snake robots are becoming more and more extensive,such as aeroengine inspection,fuel tank internal peep inspection,disaster relief and rescue activities,etc.The research work of the motion planning method of snake robot is beneficial to extend its application scenarios and improve its working ability,which has important scientific research and social practical significance.In this paper,a hyper-redundant snake robot with20-Do F and 1-Do F of the external feed system is studied,and the research work is carried out in terms of kinematical modeling,trajectory planning and motion planning.(1)Based on the kinematic characteristics of the snake robot manipulator,the kinematic mapping relationship between the control space,drive space,joint space and work space is established.According to the rope length variation and drive motor parameters,the relationship between rope tension and drive system is determined,which helps the selection of key components of motor and drive system.The kinematic model of drive space and joint space is established through the inherent geometric characteristics of the snake robot arm and the numerical solution of the nonlinear equations;the kinematic model of joint space and work space of the snake robot arm is derived based on the theory of exponential coordinates,Lie group and Lie algebra.The correctness of the kinematic modeling is verified by simulation experiments on MATLAB platform.(2)For the snake robot,the trajectory planning method of the snake robot is carried out to ensure the smoothness during the motion of the snake robot.The trajectory planning of the joint space is completed by interpolating the robot joint space with five times spline function;the trajectory planning of the working space is completed by solving the snake robot arm Jacobi matrix by using the method of finding the inverse solution at the velocity level.The feasibility of the trajectory planning method in both spaces is verified by completing the simulation of bending motion with a given joint angle and the simulation of following motion with linear and curved trajectories in the workspace in MATLAB,respectively.(3)In order to realize the collision-free motion of the snake robot in the complex and narrow environment,the kinematic planning method of the snake robot based on "head-guided" is carried out.The improved "head-guided" kinematic planning method focuses on the motion of the "head" robot manipulator of the snake robot,and the sum of the distances between the snake robot arm and the target path feature points is used as the optimization target,and weight coefficients are added to improve the kinematic accuracy of the snake robot in following the target trajectory in complex narrow environments.The motion accuracy of the snake robot in following the target trajectory in complex and narrow environments is improved by adding weight coefficients to the sum of the distances between the snake arm and the target path feature points.The feasibility and effectiveness of the method are verified by simulating the experiments in MATLAB and evaluating the experimental results in multiple dimensions.