Multi-objective Production Scheduling Of Process Industry Based On Improved Collaborative Optimization Algorithm

In the process industry,production scheduling is the core of production management of enterprise,which has important significance to improve the economic efficiency and market competitiveness of enterprises.However,the production scheduling is a kind of NP-hard optimizatiom problem with complexity,multi-constraints and multi-objectives,so it is necessary to find an efficient algorithm to solve the scheduling problem.Collaborative optimization algorithm(CO)is a multi-discipline optimization method,which can decompose the complex scheduling problem and achieve the collaborative optimization of multi-objectives,so it is important to apply CO algorithm to production scheduling in process industry.The main research of this paper is as follows:(1)To solve the problem that CO was large in computing capacity and the results were always local optimal solution,an improved CO method was presented.Firstly,a new slack factor was introduced in system optimization to ensure the existence of system feasibility that gradually reduced to kept consistent.Secondly,the objective function of subsystem was divided into two parts: consistent objective function and subsystem optimal objective function.Those two functions were added with different weight as subsystem objective function.This not only considered the consistence,but also taken into account the independence of subsystem.Finally two classic examples are optimized by the improved CO method,and the results show that it has better convergence rate and feasibility.(2)The ICO algorithm is applied to solve multi-objective optimization problem,then a multi-objective collaborative optimization method(MOICO)based on ICO is proposed.Using the two level structure of CO,the complex multi-objective problem is decomposed into many sub subjects.Each subdiscipline optimizes one objective function,and the multiple subdisciplines are coordinated by system level objective function to achieve the global optimum.Through the simulation of two standard test cases,it is proved that the MOICO algorithm is feasible for solving multi-objective optimization problems.(3)The model of multi-objective production scheduling in the process industry is set up based on the distribution and capablity of equipment,the supply of resources,and the material balance.This model is also applied to a saccharification workshop in a brewery.The scheduling instance is decomposed into three subdisciplines: capacity,water consumption and energy consumption by MOICO,then three subdisciplines are optimized by the maximum output,the lowest water resource consumption and the lowest energy resources consumption.The effectiveness of the model and the feasibility of the MOICO algorithm for solving the production cheduling problem are verified by the simulation of this scheduling example.