Four Degrees Of Freedom Of Assembly Robot Trajectory Planning And The Posture Error Analysis

Assembling work is the important process in the production process. With the rapid development of society, automatic assembling will gradually replace the manual assembling inevitably and play an important role. However, there are generally problems of low speed,unstable running and low accuracy in assembly robot. So, the robot trajectory planning and error compensation algorithm must be researched to solve these problems and improve the working efficiency and positioning accuracy of robot.First, the research object is GRB400 assembling robot. The mathematical model of robot is derived based on the coordinate transformation matrix of each joint which structured by D-H method. The obverse and inverse kinematic are calculated by means of algebraic method of separation of variables. The model is simulated by MATLAB software, which validates its correctness.Second, several different trajectory planning algorithms of robot are studied in joint space and Cartesian space. The principle and implementation method of trajectory planning in two space are introduced in detail. According to the practical demand, based on the basic track interpolation algorithm in joint space and Cartesian space, the method of using cubic B-spline to plan the trajectory of joint is proposed and the detailed procedure is given in this paper. The simulation is conducted by MATLAB. The result indicates that this algorithm can stabilize the joint movement process relatively, reduce the position error effectively and improve work efficiency.Finally, the perturbation method is used to compensate the error model. The error measuring platformof assembly robot is established, which can measure the three-dimensional coordinates in different locations. The theoretical method of geometric parameter error identificationbyusingleast squares algorithm is put forward.Theerrorcompensation experiment is performed based on calculation and identification of the robot structure parameter error.The experiment verifies the real-time performance and feasibility of the assembly robot error compensation algorithm, which laid a foundation for the further study of assembly robot.