| The realization of corporate strategic goals depends on the planning and implementation of production and business activities under strategic guidance.The primary function of production system operation management is to plan and manage system production activities.The enterprise production plan is also the overall production outline of the enterprise,which is widely used in practical applications such as enterprise resource planning ERP and manufacturing execution system MES,all need to be converted into the production operation plan that can be implemented and controlled according to the production plan outline.As the core of the manufacturing industry,the position of equipment manufacturing enterprises in the national economy and industrial construction is very important.With the continuous advancement of the industrial revolution,customer demand for products has gradually been customized and diversified,making production more complex and decentralized.Equipment manufacturing companies have begun to switch to multi-variety small batch production,and equipment products are becoming more and more flexible.The development characteristics of product production also gradually show individualization and diversification.At the same time,it also makes equipment manufacturing enterprises' multi-variety production plans face new challenges with diverse personalities,dynamic changes and unpredictable customer needs.However,through enterprise interviews and questionnaires,137 enterprises in 7 major categories of equipment manufacturing were covered.The questionnaire survey showed that,relative to the final consumer goods manufacturing enterprise,as an equipment manufacturing enterprise producing investment-type electromechanical products,due to its intensive product knowledge,more professional and complicated products,and the low customer participation in design and manufacturing,as well as the need to change and modify orders.Production planning still faces many uncertain demand issues.At present,enterprises are facing the environmental problems of diversification,customization and continuous change of market demand.In order to be able to quickly respond to changing external demands,how to make plans is an eternal theme for enterprises to organize production activities and production processes.Therefore,there have been many research results on production planning methods so far,but these methods are mainly aimed at the production plan formulation under the situation of deterministic demand or the uncertain quantity of demand,and the quantity and duration of demand are uncertain.Most of the actual production is still based on experience or mathematical methods,and through repeated experiments or "trial and error method" to formulate production plans.Faced with the multiple uncertainties in the variety,quality,quantity and delivery time of customer demands,how to describe the multiple uncertainties of customer needs and the relationship between multiple uncertain demands? How to reflect these multiple uncertain demand relationships and their demand commonality in the production planning? How to build a multi-variety production planning model with multiple uncertain demands? This is a difficult problem to be solved urgently in production planning management theory and practice.The production planning methods that are urgently needed to be solved under the multiple uncertainties in the multi-variety production of equipment manufacturing enterprises were focused.The main work completed by the research includes the following four aspects:(1)The concept of multiple uncertain demands and multiple uncertain demands of equipment manufacturing enterprises are defined.First,the basic concepts of uncertainty and related theoretical foundations are analyzed,mainly from single uncertainty research to multiple uncertain research,from the commonly used randomness and ambiguity to roughness.Then,according to the different characteristics of the research object and the different attributes of the object,they are classified and divided,and the relevant literature is sorted out,thereby defining the concept of multiple uncertainties and multiple uncertain requirements.Finally,by refining and summarizing the demand of equipment manufacturing enterprises in reality,the concept definition of multiple uncertain demands of equipment manufacturing enterprises is given.(2)The multiple uncertain requirements of the manufacturing enterprise and their relationship are analyzed,and the production strategy for the production plan is proposed.First,the uncertain demand factors such as variety,quantity,quality and delivery time are analyzed.Secondly,according to the influence process of the customer demand of the manufacturing enterprise,the relationship and mutual influence of various demands are clarified one by one.Therefore,the relationship model between the multiple uncertain demands of the customer of the manufacturing enterprise is established.Dynamic scenario analysis method,the role relationship of multiple uncertain demands of equipment manufacturing enterprises is described.The production planning response strategy under multiple scenarios of multiple uncertain demands is proposed.Finally,the dynamic stochastic programming method is used to establish the dynamic planning model of the production plan for uncertain demand.In response to the actual problems of equipment manufacturing enterprises,different production planning arrangements are adopted,including first-come-first-served,short job priority,demand time priority and minimum conversion cost strategy,simulation and comparative analysis of numerical examples.Research shows: varieties,Quantity,delivery date,quality and other demand factors exist uncertainties and related influences.The results of the calculation example prove that the model is effective and has practical value.(3)According to the order changes and emergency order scenarios of equipment manufacturing enterprises,a multi-variety production planning model for equipment manufacturing enterprises with multiple uncertain demands has been established.First of all,under the scenario of equipment manufacturing enterprise order changes and emergency orders,the changes in demand for variety,quantity,delivery time and quality are analyzed.Secondly,according to the four production goals of satisfying customer needs,minimum production planning cost,shortest production cycle and maximum profit,a multi-objective production planning model for equipment manufacturing enterprises with multiple uncertainties is established.Thirdly,in this model,not only various production constraints are considered,but also mathematical expressions are used to describe the fuzzy and uncertain quantity demand,the fuzzy and uncertain delivery time,and the rough uncertainty due to the different perceptions of customers and enterprises.Fuzzy price demands that fluctuate within a certain range are also considered.Finally,the model example is solved by using the fast non-dominated sorting genetic algorithm(NSGA-II)algorithm with elite strategy.The results show that the model is effective and feasible;at the same time,the operation results are compared with particle swarm.The algorithm solves the simulation results of the model.The comparison shows that the NSGA-II algorithm is more suitable for solving the model.(4)A multi-variable similarity production planning model for equipment manufacturing enterprises based on multiple uncertain demands is constructed.First of all,for the equipment manufacturing enterprise,the customer's discrete and random variety requirements,fuzzy delivery time requirements,random quantity requirements,and fuzzy quality requirements are analyzed.Secondly,the similarity of products and components of equipment manufacturing enterprises is analyzed,and a similarity calculation model of products or components is established.Third,for the similarity distance of products or components and the similarity of multiple uncertain requirements,a clustering model based on FCM(Fuzzy C-mean Fuzzy Clustering)is established.Then,based on the clustering model,a similar production planning model is established and solved using a multi-layer coding genetic algorithm.Finally,the cluster analysis of SAGA(simulated annealing and genetic algorithms)is compared.The results show that: SAGA clustering algorithm is more advantageous than FCM algorithm in solving this model;simulation of each model verifies the feasibility of the model and practicality. |
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