Research On Trajectory Planning Of The Delta Robot

With the rapid development of modern industrial manufacturing, Delta Parallel robot are increasingly widely used in the industry. It is claimed that a higher speed and precision. While the typical operation of Delta parallel robot is pick-and-place operations(PPO). With the demand of growing faster operation PPO, but in high-speed mode robot will reduce the accuracy, it has strong vibration, increases wear of mechanical parts and occurs a series of problems. It eventually leds to the robot’s short life and increases business costs.This thesis is mainly talking about motion planning of Delta parallel robot. Smooth and better performance of motion planning is asked for the PPO operations to improve various aspects performance and control of Delta robot. First of all, the thesis analyzes forward kinematics and inverse kinematics of the Delta parallel robot. It provides kinematics solution for the coming experiment. Then the kinematics characteristics of typical PPO operation are analyzed and the corresponding 4-5-6-7 polynomial interpolation method is proposed. It smooths respectively for indices of the curve planning such as position, velocity, acceleration and jerk. meanwhile, The synthesis of smoothing curve is used in SCARA systems. How to implement the test trajectory is the subject of this thesis. The test trajectory includes square corners between its vertical segments and horizontal segments, which are sources of velocity and acceleration discontinuities. Lamé curves are used to smooth the corners in order to provide G2-continuity throughout the test trajectory. Moreover, For the sake of making the overall trajectory as smooth as possible, the parameters defining this curve should be selected so as to minimize a cost function. The trajectory is thus synthesized by minimizing the root-mean-square value of the kinetic energy time-derivative, subject to inequality constraints. Finally we find the optimal value of objective function.Based on the moving platform model to obtain the optimal trajectory, by comparison of the experimental on prototype of Delta,we contrast effect of typical trajectory, comparing trajectory and the optimization trajectory, The experimental results show that each axis ’ vibration velocity and amplitude of the optimal trajectory in cartesian coordinate system is greatly reduced. The vibration velocity of X axis direction largely falls by 56% and there is a up to 31% drop in the Y direction, at the same time, the amplitude of the vibration peak-peak value mostly respectively falls by 69% and 23%. It Proves that the trajectory optimization design makes the Delta robot run more smoothly.so these verify the validity and superiority of trajectory optimization.