A Time Optimal Trajectory Planning Method for Overhead Cranes with Obstacle Avoidance

Overhead cranes are commonly seen industrial transportation tools. However, some obstacles may exist on the payload transportation path. To deal with this kind of problem, here, an obstacle avoidance considered trajectory planning algorithm is designed for overhead crane systems. Specifically, to achieve the obstacle avoidance objective, we decide to design trolley moving trajectories and the payload hoisting/lowering trajectories. After carefully analyzing the crane system kinematic model with payload hoisting/lowering, it is found that this system is differentially flat. By using the flatness theory, the planning problem for trolley movements and the payload hoisting/lowering is solved by planning suitable trajectories for the system flat outputs. During the planning process, various system constraints are carefully considered. Additionally, the idea of bisection is used to obtain the optimal transportation time. At last, the proposed method is tested by simulations to verify its satisfactory performance.