A strategic plan to provide management services for urban green spaces during heat waves using a collaborative truck-and-robot system

Abstract

Urban green spaces are known to provide a high level of thermal comfort during heat waves. However, urban green spaces need to be managed on a regular basis, which is time consuming and labor intensive. Autonomous robots can be a promising solution to provide management services, but their short driving range poses a significant challenge. To resolve this challenge, in this study we present a strategic management plan using a collaborative truck-and-robot system in which a truck transports multiple robots to their drop-off points, so every robot can visit their group of urban green spaces to provide management services during multi-period within their capability. To this end, we estimate management demand for urban green spaces based on the floating population data, group urban green spaces during multi-period considering robot capability and optimize routes for a truck and robots. Since our problem has a high computational complexity at the routing step, we additionally suggest solution approaches to efficiently find a near-optimal solution by incorporating a reinforcement learning model with the simulated annealing. We validate our solution approach with an application to Ulsan Metropolitan City in the Republic of Korea, demonstrating that our solution approach has competitive performance in terms of both optimality and computation time, compared with existing solution approaches. The results find that our solution approach reduces the total tour length by up to 20.73% while being four times faster than the existing solution approaches. We further conduct a sensitivity analysis with respect to robot management and technology, consisting of their available number, coverage radius, and capability, to investigate their impacts on the optimal strategic management plan. Our results indicate that using four robots with a coverage radius of 400-meter is the most effective plan to provide management services. Based on our results, we provide managerial insights from multiple perspectives.