Reserrch On Hybrid Flow Shop Scheduling Considering Energy Efficiency Under Time-Of-Use Electricity Tariffs

With the continuous progress of society and rapid economic development,the global energy problem has become increasingly prominent.The manufacturing industry,especially the mechanical manufacturing industry,has created great energy consumption and caused great pollution to the environment while creating economic benefits for our country.The manufacturing industry mainly consumes electricity,but the demand for electricity is always changing with peak and valley fluctuations.It is because such unstable demand brings a series of problems to power generation and power supply,which brings environmental and economic negative effects.Time of use electricity tariffs(TOU),one of the most widely used applications in the smart grid situation,refers to the different electricity prices in different periods.In order to solve the economic and environmental problems caused by the electricity demand fluctuation,the TOU mechanism is adopted in China.The aim is to reduce the electricity consumption and environmental emission in the peak period.From the perspective of consumers,reasonable planning of electricity consumption and time intervals can reduce the cost of electricity consumption.In the whole machinery manufacturing industry,the application of CNC machine tools is more and more extensive and the quantity is more and more large.Due to large total energy consumption and low energy efficiency of CNC machine tools,it is necessary to reduce the total energy consumption and improve the energy efficiency of machine tools.Firstly,the energy consumption characteristics of CNC machine tools is studied in this paper,and the energy efficiency function of the NC machining system is established.Based on the orthogonal test design method,the influence of the numerical control process parameters on the energy efficiency of the machine tool is carried out.The optimal process parameter combination is solved by optimizing the energy efficiency of machine tools Secondly,the hybrid flow shop scheduling problem is studied,which synthetically considers the scheduling efficiency and energy consumption.The scheduling efficiency index is characterized by the maximum completion time,and the energy consumption results are characterized by the cost of energy consumption.In order to avoid the problem of normalization and weight setting in the process of transforming multi-objective into single objective algorithm,the strength Pareto evolutionary algorithm is adopted in this paper.The optimization parameters of the single layer energy efficiency are applied to the simulation of mixed flow shop scheduling,and the double layer optimization scheduling of mixed flow shop is realized,which provides theoretical and technical support for the energy-saving optimization of machine tools and workshops for sustainable manufacturing.Then,the TOU tariffs is introduced to comprehensively consider the scheduling efficiency and energy consumption.A coding method of fusion process,equipment and processing time is put forward.The strength Pareto evolutionary algorithm(SPEA2)is used to optimize the completion time and power consumption cost simultaneously.The result of the case simulation shows that through the reasonable arrangement of processing time points and processing equipment in each process,it can avoid the high electricity price period and select low energy consumption machine at the same time,and reduce the total power cost.From the level of power supply,the system of TOU price is realized to promote the rational transfer of electricity load by power utilities,and achieves the effect of peak shaving and valley filling.Finally,a small production scheduling system is built for the case of hybrid flow shop,and the optimization algorithm used in this paper is integrated,which can realize the reading of order task and the online allocation of scheduling scheme.