Flexible Job Shop Scheduling Optimization Method And Case Studies For Energy-saving

The manufacturing industry is the foundation of national economic development.At present,the manufacturing industry generally has some problems,such as high energy consumption and low energy utilization in the production process.As an effective way to reduce energy consumption in mechanical machining workshop,scheduling has been widely concerned by scholars at home and abroad.Dynamic events will occur in the process of mechanical processing,such as urgent job arrivals or machine breakdowns,which interfere the execution of the scheduling and affect the energy consumption and makespan.Considering the flexible of process routes and machine tool and handling equipment selection in the flexible job shop,the flexible job shop scheduling problem under the dynamic events trigger has higher flexibility and adaptability,and has significant energy-saving optimization space.Therefore,with the support of the National High-Tech R&D Program of China(863 Program)(No.2014AA041506)and National Natural Science Foundation of China(No.51475059)and National Key Research and Development Program of China(No.2017YFF0207903),the flexible job shop scheduling optimization method for energy-saving under the dynamic events with urgent job arrivals and machine breakdown is proposed.Firstly,a dynamic scheduling system based on dynamic events and a flexible job shop dynamic scheduling framework are proposed.Based on that,the impact of dynamic events on flexible job shop scheduling,the energy consumption of machine,the energy consumption of handling equipment are analyzed.Secondly,the energy saving optimization model and method of flexible job shop dynamic scheduling are studied.Based on the rescheduling response strategy when dynamic events occur,the energy consumption characteristics of the rescheduling process are analyzed.Based on that,the energy saving optimization model of flexible job shop dynamic scheduling to minimize energy consumption,completion time and robustness is established,which optimal variable is the process route selection,the machine tool selection,and the processing sequence on machine tool.And the model is solved based on Multi-objective Gravitational Search algorithm(MOGSA).Thirdly,the energy saving optimization model and method of flexible job shop scheduling considering material handling are studied.Considering the influence of the material handling process on the dynamic scheduling,the energy consumption characteristics of the material handling process based on the dynamic event are analyzed.On this basis,the dynamic scheduling energy saving optimization model is established,which the optimization goal is energy consumption,completion time and robustness,optimal variable is the process route selection,the machine tool selection,and the processing sequence on machine tool,handling equipment selection,the handling sequence on handling equipment.And the model is solved based on MOGSA algorithm.Finally,taking the scheduling in mechanical machining workshop in a mechanical manufacturing Co.,LTD in Chongqing as an example,the energy saving optimization method for flexible job shop and the energy saving optimization method considering the material handling are applied respectively.The validity of the proposed model are verified by the comparison of different rescheduling schemes.