High-speed point-to-point trajectory planning of a 2-DOF cable driven parallel manipulator

Abstract

Suitable trajectory planning methods can improve the smoothness, rapidity and efficiency of motion control of robot. Polynomial and trigonometric formulation are often adopted to realize smooth trajectory planning for cable-driven parallel manipulator, while the two approaches are complex and have weak rapidity. A new combined planning method with S-trapezoid curve is proposed for the point-to-point motion of planar 2-DOF cable-driven parallel manipulator, and the unilateral constraints on cable tensions are computed according to the dynamic model. Considering the specific point-to-point trajectory includes a list of target points that must be reached in sequence, thus it can be divided into the initial segment, the middle segment and the final segment. And then the combined planning method with S-trapezoid curve is applied to plan the velocity curve of the three segments. The acceleration is zero at the initial and final point, while it's nonzero at the middle points. The dynamic trajectory planning can be realized with this state. The proposed planning method is implemented on a 2-DOF cable-driven parallel manipulator, and the simulation results indicate that the unilateral constraints on cable tensions could be satisfied and the acceleration curve is simple first-order curve, thus high-speed point-to-point motion could be realized.