Increasing attention has been paid to the application of Unmanned Aerial Vehicles (UAVs) in traffic field. Existing studies on UAVs in road patrol task assignment rarely integrate the actual requirements of multiple bases, charging problems during inspection and multiple types of UAVs into the patrol model, and rarely consider the fastest time to complete the patrol of all task points as the optimization target. In addition, most existing solving algorithms are difficult to use to directly solve problem models meeting the above requirements and objectives, and some existing algorithms need to be improved in terms of solving quality. In order to solve those problems, a task assignment model for road patrol by multiple UAVs with multiple bases and rechargeable endurance is established, and a time-priority immune clonal selection algorithm with optimization-revision is proposed. The optimal sequence of task points is obtained by the immune clonal selection algorithm, and the time-priority method is adopted to divide the sequence of task points. The optimal UAV paths are further optimized and modified. With 20 task points, the experimental results show that the earliest completion time obtained by the proposed algorithm decreased by 1.071 and 2.1209 compared with the earliest reachable time particle swarm optimization algorithm and the improved dynamic programming ant colony algorithm, respectively. The results indicate that proposed algorithm achieves better performance in terms of solution quality. In addition, experiments with 50 and 100 task points show that the algorithm is also suitable for medium and large scale problems.
INDEX TERMSImmune clonal selection algorithm, optimization-revision, rechargeable endurance, road patrol, time priority, UAV. I. INTRODUCTION Unmanned aerial vehicles (UAVs) have made remarkable achievements in the military [1], [2] and have been widely used in various civilian fields as well [3]-[5]. In recent years, UAVs have shown a broad application prospects in the field of transportation. In the future, it will play an important role in urban traffic planning, road patrol, bridge inspection, traffic dredging, accident emergency treatment, traffic accident forensics, criminal tracking and other transportation aspects [6]-[8]. Due to its flexible control, free from traffic restrictions on the road, wide patrol range and lack of a need for manual intervention in the whole process. UAVs can The associate editor coordinating the review of this manuscript and approving it for publication was Ying Li. LINHUI CHENG (M'19) was born in Xiangyang, Hubei, China, in 1980. She received the B.S. degree in computer software from Central China Normal University, Wuhan, China, in 2002, and the M.S. degree in computer science and technology from South-Central University for Nationalities, Wuhan, in 2008. She is currently pursuing the Ph.D. degree in computer science and technology with the