A new automatic motion planning algorithm for a 4-degree-of-freedom parallel kinematic manipulator based on the centre sphere method

Abstract

This study investigates a new automatic motion planning algorithm for industrial robots performing a pick-and-place task in an obstacle-free workspace. The new technique finds an optimal trajectory for a parallel kinematic manipulator. The centre sphere method and multi-objective optimisation are used to solve this problem. To obtain an optimal path, an objective function that includes a hypothetical jerk fitness value, a path length function and a virtual obstacle avoidance function is defined, and the path planning problem is solved using particle swarm optimisation. For greater efficiency, the planning problem is modified to include physical constraints on the robot. The method is tested on a 4-degree-of-freedom parallel kinematic manipulator through simulations, where the optimum virtual sphere radius is obtained. Experiments are performed with an actual parallel kinematic manipulator, and a comparison of the performance of the robot executing the same tasks with trajectories obtained using the new method and two existing methods is made. The results show the efficiency and the effectiveness of the proposed approach in determining the optimal trajectory for a 4-degree-of-freedom parallel kinematic manipulator in an obstacle-free workspace. © 2015, IMechE. All rights reserved.