Intermediate charging and sudden failure of automatic guided vehicles(AGVs)interrupt and severely affect the stability and efficiency of scheduling.Therefore,an AGV scheduling approach considering equipment failure an...Intermediate charging and sudden failure of automatic guided vehicles(AGVs)interrupt and severely affect the stability and efficiency of scheduling.Therefore,an AGV scheduling approach considering equipment failure and power management is proposed for outfitting warehouses.First,a power consumption model is established for AGVs performing transportation tasks.The powers for departure and task consumption are used to calculate the AGV charging and return times.Second,an optimization model for AGV scheduling is established to minimize the total transportation time.Different conditions are defined for the overhaul and minor repair of AGVs,and a scheduling strategy for responding to sudden failure is proposed.Finally,an algorithm is developed to solve the optimization model for a case study.The method can be used to plan the charging time and perform rescheduling under sudden failure to improve the robustness and dynamic response capability of AGVs.展开更多
In recent years,multiple-load automatic guided vehicle(AGV)is increasingly used in the logistics transportation fields,owing to the advantages of smaller fleet size and fewer occurrences of traffic congestion.However,...In recent years,multiple-load automatic guided vehicle(AGV)is increasingly used in the logistics transportation fields,owing to the advantages of smaller fleet size and fewer occurrences of traffic congestion.However,one main challenge lies in the deadlock-avoidance for the dispatching process of a multiple-load AGV system.To prevent the system from falling into a deadlock,a strategy of keeping the number of jobs in the system(NJIS)at a low level is adopted in most existing literatures.It is noteworthy that a low-level NJIS will make the processing machine easier to be starved,thereby reducing the system efficiency unavoidably.The motivation of the paper is to develop a deadlock-avoidance dispatching method for a multiple-load AGV system operating at a high NJIS level.Firstly,the deadlock-avoidance dispatching method is devised by incorporating a deadlock-avoidance strategy into a dispatching procedure that contains four sub-problems.In this strategy,critical tasks are recognized according to the status of workstation buffers,and then temporarily forbidden to avoid potential deadlocks.Secondly,three multiattribute dispatching rules are designed for system efficiency,where both the traveling distance and the buffer status are taken into account.Finally,a simulation system is developed to evaluate the performance of the proposed deadlock-avoidance strategy and dispatching rules at different NJIS levels.The experimental results demonstrate that our deadlock-avoidance dispatching method can improve the system efficiency at a high NJIS level and the adaptability to various system settings,while still avoiding potential deadlocks.展开更多
An artificial potential field method based on global path guidance(G-APF)is proposed for target unreachability and local minima problems of the conventional artificial potential field(APF)method in complex environment...An artificial potential field method based on global path guidance(G-APF)is proposed for target unreachability and local minima problems of the conventional artificial potential field(APF)method in complex environments with dynamic obstacles.First,for the target unreachability problem,the global path attraction is added to the APF;second,an obstacle detection optimisation method is proposed and the optimal virtual target point is selected by setting the evaluation function to improve the local minima problem;finally,based on the obstacle detection optimisation method,the gravitational and repulsive processes are improved so that the path can pass through the narrow channel smoothly and remain collision-free.Experiments show that the method optimises 40.8%of the total path corners,reduces 81.8%of the number of path oscillations,and shortens 4.3%of the path length in Map 1.It can be applied to the vehicle obstacle avoidance path planning problem in complex environments with dynamic obstacles.展开更多
Multiple Automatic Guided Vehicle(multi-AGVs)management systems provide an effective solution to ensuring stable operations of multi-AGVs in the same scenario,such as flexible manufacturing systems,warehouses,containe...Multiple Automatic Guided Vehicle(multi-AGVs)management systems provide an effective solution to ensuring stable operations of multi-AGVs in the same scenario,such as flexible manufacturing systems,warehouses,container terminals,etc.This type of systems need to balance the relationship among the resources of the system and solve the problems existing in the operation to make the system in line with the requirement of the administrator.The multi-AGVs management problem is a multi-objective,multi-constraint combinatorial optimization problem,which depends on the types of application scenarios.This article classifies and compares the research papers on multi-AGVs management in detail.Firstly,according to the different dimensions of the problem,the multi-AGVs management system is analyzed from three perspectives,namely,1)task dimensiondispatch,2)spatial dimension-path,and 3)time dimension-scheduling.The detailed comparison between the three dimensions and their respective solutions are discussed in detail as well.Secondly,according to their utility,the multi-AGVs management problems are divided into three categories:1)cost reduction,resource-oriented,2)efficiency improvement,problem-oriented,3)personalized demand,goal-oriented.The algorithm and methods of the different utility-oriented are analyzed and discussed.The related literature is summarized and corresponds to the composition of the multi-AGVs management system and the multi-AGVs management problems.Finally,according to the literature review,suggestions are made for further research.展开更多
基金Supported by the China High-Tech Ship Project of the Ministry of Industry and Information Technology under Grant No.[2019]360.
文摘Intermediate charging and sudden failure of automatic guided vehicles(AGVs)interrupt and severely affect the stability and efficiency of scheduling.Therefore,an AGV scheduling approach considering equipment failure and power management is proposed for outfitting warehouses.First,a power consumption model is established for AGVs performing transportation tasks.The powers for departure and task consumption are used to calculate the AGV charging and return times.Second,an optimization model for AGV scheduling is established to minimize the total transportation time.Different conditions are defined for the overhaul and minor repair of AGVs,and a scheduling strategy for responding to sudden failure is proposed.Finally,an algorithm is developed to solve the optimization model for a case study.The method can be used to plan the charging time and perform rescheduling under sudden failure to improve the robustness and dynamic response capability of AGVs.
基金supported by the National Natural Science Foundation of China(Nos.52005427,61973154)the National Defense Basic Scientific Research Program of China(No.JCKY2018605C004)+1 种基金the Natural Science Research Project of Jiangsu Higher Education Institutions(Nos.19KJB510013,18KJA460009)the Foundation of Graduate Innovation Center in Nanjing University of Aeronautics and Astronautics(No.KFJJ20190516)。
文摘In recent years,multiple-load automatic guided vehicle(AGV)is increasingly used in the logistics transportation fields,owing to the advantages of smaller fleet size and fewer occurrences of traffic congestion.However,one main challenge lies in the deadlock-avoidance for the dispatching process of a multiple-load AGV system.To prevent the system from falling into a deadlock,a strategy of keeping the number of jobs in the system(NJIS)at a low level is adopted in most existing literatures.It is noteworthy that a low-level NJIS will make the processing machine easier to be starved,thereby reducing the system efficiency unavoidably.The motivation of the paper is to develop a deadlock-avoidance dispatching method for a multiple-load AGV system operating at a high NJIS level.Firstly,the deadlock-avoidance dispatching method is devised by incorporating a deadlock-avoidance strategy into a dispatching procedure that contains four sub-problems.In this strategy,critical tasks are recognized according to the status of workstation buffers,and then temporarily forbidden to avoid potential deadlocks.Secondly,three multiattribute dispatching rules are designed for system efficiency,where both the traveling distance and the buffer status are taken into account.Finally,a simulation system is developed to evaluate the performance of the proposed deadlock-avoidance strategy and dispatching rules at different NJIS levels.The experimental results demonstrate that our deadlock-avoidance dispatching method can improve the system efficiency at a high NJIS level and the adaptability to various system settings,while still avoiding potential deadlocks.
基金supported by the Zhejiang Province New Young Talent Plan Project in 2022 under Grant No.2022R431B021。
文摘An artificial potential field method based on global path guidance(G-APF)is proposed for target unreachability and local minima problems of the conventional artificial potential field(APF)method in complex environments with dynamic obstacles.First,for the target unreachability problem,the global path attraction is added to the APF;second,an obstacle detection optimisation method is proposed and the optimal virtual target point is selected by setting the evaluation function to improve the local minima problem;finally,based on the obstacle detection optimisation method,the gravitational and repulsive processes are improved so that the path can pass through the narrow channel smoothly and remain collision-free.Experiments show that the method optimises 40.8%of the total path corners,reduces 81.8%of the number of path oscillations,and shortens 4.3%of the path length in Map 1.It can be applied to the vehicle obstacle avoidance path planning problem in complex environments with dynamic obstacles.
基金funded by the National Key Research and Development Program of China(No.2019YFB1310003)by the National Natural Science Foundation of China(Nos.U1913603,61803251 and 51775322)funded by the Shanghai Collaborative Innovation Center of Intelligent Manufacturing Robot Technology for Large Components(No.ZXZ20211101).
文摘Multiple Automatic Guided Vehicle(multi-AGVs)management systems provide an effective solution to ensuring stable operations of multi-AGVs in the same scenario,such as flexible manufacturing systems,warehouses,container terminals,etc.This type of systems need to balance the relationship among the resources of the system and solve the problems existing in the operation to make the system in line with the requirement of the administrator.The multi-AGVs management problem is a multi-objective,multi-constraint combinatorial optimization problem,which depends on the types of application scenarios.This article classifies and compares the research papers on multi-AGVs management in detail.Firstly,according to the different dimensions of the problem,the multi-AGVs management system is analyzed from three perspectives,namely,1)task dimensiondispatch,2)spatial dimension-path,and 3)time dimension-scheduling.The detailed comparison between the three dimensions and their respective solutions are discussed in detail as well.Secondly,according to their utility,the multi-AGVs management problems are divided into three categories:1)cost reduction,resource-oriented,2)efficiency improvement,problem-oriented,3)personalized demand,goal-oriented.The algorithm and methods of the different utility-oriented are analyzed and discussed.The related literature is summarized and corresponds to the composition of the multi-AGVs management system and the multi-AGVs management problems.Finally,according to the literature review,suggestions are made for further research.
