Research On Path Planning Of 6-UCU Parallel Robot Based On Quaternion

Parallel Robot has been a hot research topic in the field of robot because of its advantages such as high stiffness,stable structure,small cumulative error and excellent dynamic performance.Trajectory planning is one of the key factors that affect the stability and comprehensive performance of the end motion of a parallel robot.Because of the low efficiency and singularity of the interpolation methods such as rotation matrix,axis angle and Euler angle,this paper studies the trajectory planning of 6-dof parallel robot based on quaternion.Firstly,the 6-UCU parallel robot is taken as the research object,and the inverse kinematics equation is constructed by numerical method.The positive and negative velocity and acceleration equations of the robot are obtained by using the influence coefficient method,and the reliability of the kinematics results is verified by virtual prototype simulation.After determining the accuracy of the positive solution equation,a Monte Carlo method method is used to solve the pose of the parallel robot to reach the workspace.Secondly,a spherical linear attitude interpolation algorithm based on quaternion theory is proposed,and an equal step pose interpolation model is constructed.Based on the analysis of the traditional pose interpolation algorithms in European space and attitude space,the disadvantages of using axis angle and Euler angles for pose interpolation are analyzed theoretically,a spherical linear attitude interpolation algorithm based on quaternion theory is proposed.Combining three kinds of attitude interpolation algorithms with position interpolation,a position-attitude interpolation model with equal step length is constructed,and the visualization of position-attitude interpolation is realized by using MATLAB.Simulation results show that the quaternion-based pose interpolation algorithm has higher interpolation stability and efficiency.Finally,the S-type velocity planning algorithm is improved to solve the problems of acceleration jump of T-type velocity curve and too many segments of S-type velocity curve.The algorithm introduces path length and other constraints into the traditional S-type velocity curve to realize the controllable speed curve segment,so as to deal with a variety of applications.The velocity coordination between position and attitude is solved by normalization,and the space trajectory planning process of Descartes is summarized.In Simulink,the trajectory of a 6-UCU parallel robot is simulated to evaluate the feasibility and practicability of the quaternion-based trajectory planning algorithm.From the analysis of the simulation results,it can be seen that the algorithm can effectively reduce the flexible impact of the machine,thus ensuring the stability and motion accuracy of the parallel robot when drilling.