Vehicle routing problem with pickup and delivery of multiple robots for hospital logistics

Abstract

This paper considers multiple mobile robots for hospital logistics application. To increase the efficiency of using multiple robots, more than one delivery tasks can be assigned to a robot instead of delivering one package at a time. Since a robot can accept more than one task while delivering, a real-time routing method for visiting multiple pickup and delivery positions is required. This paper proposes an exhaustive search algorithm that reduces the computational resource for finding the shortest path while promising global minimum solution. This algorithm derives the shortest path that visits multiple positions by finding possible combinations with minimum iteration of the function while not allowing inversely visiting of pickup and delivery position. Applying distance matrix to the generated combination result, the total travel distance can be derived. The robot that provides the minimum total travel distance is selected for the new task. The algorithm is tested by the simulation and the result shows that the proposing method not only increases the delivery efficiency but also reduces the computational burden for exhaustive searching the shortest path of all robots for assigning the delivery task in real-time.