An Online Time-Optimal Trajectory Planning Method for Constrained Multi-Axis Trajectory With Guaranteed Feasibility

Abstract

Online time-optimal trajectory planning exists in a wide range of applications such as computer numerical control (CNC) manufacturing, robotics and autonomous vehicles. Generally, the methods to generate such time-parameterized trajectory can be categorized as offline methods and online methods. Offline methods tend to generate time-optimal trajectory while it is computationally prohibitive for high frequency real-time applications. Current online methods are computationally efficient but either deal with the sparse waypoint trajectories or sacrifice the time optimality a lot. This letter innovatively proposed a time-optimal switching trajectory index coordination (TOS-TIC) strategy to solve the online time-optimal planning problem for continuous multi-axis trajectories. The proposed method is able to generate time-optimal trajectory for continuous geometric paths while considering high order kinematic constraints. The time-optimality of the trajectory planned by TOS-TIC is nearly the same as the offline planned optimal results. Meanwhile, the proposed method is computationally efficient for online applications. The proposed TOS-TIC planning strategy is an universal approach and firstly able to solve the online time-optimal trajectory planning problem for constrained continuous multi-axis trajectories, which has excellent application prospect in modern automatic industry and intelligent robots/vehicles.