A Real-time Look-ahead Trajectory Planning Methodology for Multi Small Line Segments Path

Abstract

When a robot is required to machine a complex curved workpiece with high precision and speed, the tool path is typically dispersed into a series of points and transmitted to the robot. The conventional trajectory planning method requires frequent starts and stops at each dispersed point to complete the task. This method not only reduces precision but also causes damage to the motors and robot. A real-time look-ahead algorithm is proposed in this paper to improve precision and minimize damage. The proposed algorithm includes a path-smoothing algorithm, a trajectory planning method, and a bidirectional scanning module. The path-smoothing method inserts a quintic Bezier curve between small adjacent line segments to achieve $$G^{2}$$ G 2 continuity at the junctions. The trajectory planning method utilizes a quartic polynomial and a double-quartic polynomial that can achieve a constant velocity at the velocity limitation. The bidirectional scanning module calculates the velocity at each trajectory planning segment point, simplifying calculation complexity and can be run in real time. The feasibility of the proposed algorithm is verified through simulations and experiments, which can be run in real time. In addition, high machining precision can be achieved by adjusting the relevant parameters.

Trajectory Smoothing Planning of Delta Parallel Robot Combining Cartesian and Joint Space

“…To improve the dynamic performance of the delta parallel pickup robot in high-speed pick-and-place processes, taking time and acceleration as optimization objectives, a trajectory optimization method based on the improved butterfly optimization algorithm (IBOA) was proposed [6]. Zhang et al [7] inserted a quintic Bezier curve between small adjacent line segments to achieve velocity and acceleration continuity at the connecting points, and a quartic polynomial was adopted to achieve a constant velocity at the velocity limitation. To solve the problem of trajectory continuity, some fitting curves were presented, such as quintic and cubic nonuniform rational NURBS curves [8,9], the quintic Pythagorean hodograph (PH) curve [10], combining cubic splines with a linear segment with parabolic blends [11], and the S-curve [12].…”