Multi-robot coordination for high-speed pick-and-place tasks

This paper deals with the problem of multi-robot coordination in high-speed pick-and-place tasks. In order to solve the multi-robot coordination problem, the single-robot sorting algorithms need to be analyzed first. In most practical situations of high-speed pick-and-place tasks, the first-in-first-out(FIFO) rule is adopted as the sorting algorithms, which is verified to be inefficient in overload system. A novel method named the Second-Shortest-Sorting-Time (SSST) rule which is proved to be more efficient in overload system is proposed based on the Shortest-Sorting-Time (SST) rule. Multi-robot coordination is studied on the basis of the three sorting algorithms. Taking double-robot scenario as an example, the purpose is to arrange the position of two robots and find a proper combination of the multi-robot sorting algorithms for the items on a moving conveyor belt. Results obtained from the simulations show that SSST-SSST rule performs optimally for different tested instances. If the optimized sorting algorithm is used in practical application, the sorting rate can be significantly increased.