Research On Energy-efficient Scheduling Of Flexible Job Shop Considering Interval Processing Time

As the key link of resource allocation and management decision in intelligent manufacturing system,workshop scheduling plays an extremely important role in manufacturing industry.Adopting efficient scheduling optimization method can quickly improve the production efficiency of enterprises and reduce energy consumption,so as to effectively realize the collaborative optimization of green indicators and economic indicators.Flexible job shop scheduling problem is a class of typical problems in shop scheduling,widely used in all kinds of flexible manufacturing,different from the machine uniqueness of job shop scheduling,the machine selection in flexible job shop scheduling is more flexible,practical production can be flexible based on the existing resource allocation of science,thus improve the flexible manufacturing process.In traditional flexible job shop scheduling,time parameters such as workpiece processing time and completion time are usually defined as deterministic values,however,uncertainties exist widely in the actual production of the manufacturing workshop,it is difficult to obtain accurate processing information due to the influence of uncertain factors such as machine failure,operator’s cognition level and production environment.Therefore,this paper focused on the flexible job shop energy-saving scheduling with uncertain workpiece processing time,combined the interval number theory with the flexible job shop,used interval number to represent the uncertain time parameters related to the workpiece,and studied the flexible job shop energy-saving scheduling considering the interval time.The specific research contents are as follows.This paper expounds the research background and significance of the subject;On the basis of relevant theories,the research status of flexible job shop scheduling skill scheduling and uncertain job shop scheduling problem at home and abroad is summarized.Based on the existing research status,the flexible job shop energy-saving scheduling problem considering interval time is proposed.Based on the consideration of energy consumption and resource constraints,the interval number theory is combined with multi-objective flexible job shop scheduling.The scheduling goals are to minimize the maximum interval completion time and total energy consumption,and the interval optimization model is constructed for the flexible job shop scheduling problem considering interval time.At the same time,an interval multi-objective evolutionary algorithm is designed according to the dominant relationship of the interval possibility degree.In order to test the performance of the algorithm,based on the established interval multi-objective model,three examples of different sizes are constructed in this paper.NSGA-II and SPEA-II are used as the comparison algorithm,and two performance indexes of inversion generation distance(IGD)and coverage set measure(C measure)are selected as the evaluation indexes.The advantages of the proposed algorithm are verified by the experimental analysis of the quality,diversity and evaluation indexes of the three algorithms.Then,taking a manufacturing enterprise as an example,the interval multi-objective evolutionary algorithm designed in this paper is used to solve the problems,which provides decision support and reference for the enterprise to make a more reasonable production scheduling scheme.