Optimizing truck scheduling in a cross-docking system with preemption and unloading/loading sequence constraint

To solve the truck scheduling problem with preemption and unloading/loading sequence requirement in a multi-door cross-docking system, preemption rules are analyzed and a mathematical programming model is formulated aiming at minimizing total operation time. Then, a hybrid meta-heuristic algorithm based on particle swarm optimization and tabu search (PSO-TS) is proposed. Using Taguchi method, PSO-TS is tuned to attain the best robustness. Finally, computational experiments are carried out by using problem instances with different scales to compare the performances of PSO-TS and an improved PSO in the literature. Results show that PSO-TS had a significant advantage in computational time and produced better solutions with the increase of problem sizes.