Truck Scheduling Problem in Logistics of Crossdocking

This report addresses an important crossdocking planning operation which is the scheduling of trucks at crossdocking terminals. The study focuses on the problem in a resource-constrained crossdock. The truck scheduling problem in this scenario decides on the succession of incoming and outgoing trucks at the dock doors of the crossdocking terminal, subject to the availability of the crossdock resources including dock doors and material handling systems. Moreover, the resources are assumed non-preemptive making the feasibility of the problem precede its optimality as it might be entrapped in deadlock. A two-phase heuristic algorithm is proposed for the problem. First, a heuristic search is deployed to construct a feasible sequence of trucks for the assignment to dock doors and second, a rule-based heuristic is introduced to assign each sequenced truck to a proper dock door such that significant savings in the truck schedule length (as makespan) is achieved. Extensive experiments are conducted to evaluate the efficiency of the algorithm in terms of deadlock avoidance and solution quality. The evaluation is carried out against the solutions generated by the exact mathematical model of the problem and a constructive heuristic developed for a similar truck scheduling problem. Experimental results demonstrate that the proposed algorithm is robust in avoiding deadlock and generates feasible solutions for the instances where the other two approaches cannot. Furthermore, significant improvement in solution quality is achieved by augmenting the algorithm to a multi-start heuristic.