An optimization model for forklift utilisation and congestion control in cross-docking terminals

This study aims to optimize cross-docking (CD) performance and efficiency in CD assignment problems by maximising forklift utilisation inside the terminal. ‘We present a new Mixed-Integer Nonlinear programming (MINLP)’ model that considers truck-door assignment and forklift utilisation inside the airport. One objective is to enhance the quality of truck-door by minimising the total transshipment costs, including the penalty cost associated with forklift underutilisation, the total forklift travel distance cost, and the total weighted loading unloading and operator cost. Another objective is to control the forklift congestion by minimising the total number of forklifts needed to transfer products between multiple doors inside the terminal. Two algorithms, including the tabu-search and the best-local-point-finder, are proposed to accomplish these objectives. Our computational results show the advantage of the proposed algorithms over the CPLEX commercial solver.