【作者】 张志峰；

【导师】 肖人彬；

【作者基本信息】 华中科技大学 ， 工业工程， 2008， 博士

【摘要】 离散制造企业中,物料、零件等的加工时间只占企业生产过程的很少部分,大部分时间是物料或零件处于停滞或装卸、搬运、包装和运送等物流过程中。因此,根据制造企业的生产特点,通过有效地控制企业生产物流、合理调配生产物资、优化制造过程等手段,找出合适的生产物流控制方法,进而对由不同控制或优化方法得出的不同方案进行有效的比较与评价,以及对生产系统的运行状态与运行效率进行评价分析,对于恰当地选择更为适合本企业的物流技术方案以及准确分析影响企业生产物流的关键因素,从而提升国内制造企业的整体物流水平有着重要的意义。另一方面,离散制造企业的内、外部环境处于不断变化之中,生产系统具有一定的随机性、模糊性等不确定性特点,而这些不确定性都可以用“熵”这个统一的概念来描述,这也是熵理论应用于度量制造企业系统信息的基础。本文借鉴国内外相关研究成果,运用耗散结构理论,信息熵理论等相关理论,在调研和分析实际离散制造企业生产物流的基础上,通过建立离散制造企业物流系统熵模型,对离散制造企业以资金流为推动的总体运行状况、生产物流的结构与运行有序性、单元制造的复杂性等进行评价研究,为企业的生产物流管理提供必要的决策依据和技术支持。从企业系统信息转化的度量、企业系统的无序与失稳的度量以及企业系统不确定性的评价与度量三个方面对企业系统的熵理论进行论述。依据制造企业系统熵结构各组成部分的不同性质进行划分并阐述各部分相互关系。在分析总结国内外熵模型理论研究的基础上,归纳提出制造系统熵模型为熵变模型、静态熵模型、动态熵模型、批量熵模型和流程柔性熵模型五种形式并讨论说明各自特点及适用范围,为后续熵模型的建立以及实施生产物流评价打下基础。根据突变理论,选取尖点突变模型建立企业系统的耗散结构模型,由此判断企业系统形成耗散结构的条件。应用耗散结构理论,通过对企业系统耗散结构的形成过程及形成条件的分析研究,建立以资金流为推动的企业系统熵变模型。结合企业系统的实际情况,提出具有可操作性的企业系统熵变计算公式,依据所建模型及公式对企业系统的运行状况进行实例评价分析,结果与企业实际发展情况基本吻合。结合条件熵的性质、特征,依据信息的发送与反馈原则,建立具有动态性和一般性的系统结构熵模型,而后在分析企业生产系统结构特点基础上,对模型进行特例处理,建立生产系统的结构熵模型,使得针对模型的计算求解更具可操作性。针对目前生产物流系统中由于不同生产方式或生产结构所造成的不同的运行状况间缺乏定量评价与比较方法的问题,从模糊熵概念出发,依据信息熵原理及有序度定义,建立生产系统要素条件下物流运行熵模型,同时从生产物流系统构成要素角度确立生产系统运行评价指标体系。最后通过实例较好地验证了使用此定量分析方法来评价生产物流系统运行有序性的合理性,并扩展此类运行熵模型的应用范围。对制造系统复杂性的效用进行深入分析,通过制造系统复杂性与效用函数的相互关系及其随时间的发展变化趋势来说明复杂性对制造系统的影响并提出相应的应对策略。在信息熵理论的基础上,分别建立单元制造系统的静态熵与动态熵模型并对制造资源的状态认定进行了说明。基于上述理论与方法研究成果,通过分析某个制造车间实施单元制造前后的生产物流,应用所建熵模型,对车间生产物流的结构以及运行的有序性、复杂性等进行评价研究,其结果验证了模型的可行性、有效性和实用性。更多还原

【Abstract】 In a discrete manufacturing factory,the processing time of materials or parts is just a little part of production course and the most time of production course is that materials or parts are in one of logistics states of stagnation,loading and unloading,conveying,casing and carrying,etc.Therefore,to find out some suitable ways of controlling production logistics and effectively compare and evaluate different scheme or analyze and evaluate the running state and efficiency of production systems stands significent influence for correctly selecting more suitable logistic technical scheme and analyzing the key factor acted on production logistics,and improving holistic level of production logistics of civil enterprise by effectively controlling production logistics,logically preparing production materials and optimazing producing process according to the characteristic of manufactuing enterprise.In addition,a challenging and ever-changing environment of manufacturing systems leads that production systems are of uncertain characteristic of some randomicity and fuzziness. These uncertain characteristic can be described by entropy,a uniform concept,which is a basis to measure information of manufacturing systems by entropy theory.Using dissipative structure and information entropy relevant theoretical research achievements for reference,operating status of logistics,orderliness of structure and operation of production logistics systems and complexity of cellular manufacturing are deeply researched on the base of investigating and analysing on production logistics systems of discrete manufactuing enterprise to dicuss an approach to optimizing logistics based on entropic theory,and supply necessary foundation and technical support for management and decision,through developing entropy models of logistics systems of discrete manufactuing systems.Entropy theory of enterprise systems is discussed from measurement of information transforming,measurement of orderlessness and instability and measurement of uncertainty three parts.Entropic structure of manufactuing systems is divided by the nature of different parts of manufactuing systems and mutual relationship of different parts is expounded.Five entropy models of manufactuing systems are reduced and developed,ie.entropy change model,static entropy model,dynamic entropy model,lot entropy model and flexible routing entropy model,and their trait and applied domain are dicussed and illustrated in order to lay the foundation for the latter research.Dissipative structure model of enterprise systems is constructed according to mutation theory,which is applied to judge the condition that enterprise systems form dissipative structure.The process and condition of dissipative structure formed is researched by means of dissipative structure theory.The entropy change model drived by currency flow is set up and a formula by which value of entropy chang can be calculated is shown integrated the actual status of enterprise system,then an example is validated using the model and formula and the results met the fact well.The structural entropy model with dynamic and general characteristic is builded based on the mechanism of the sending and feedback of information according to definition of the structural entropy and using the principle of the conditional entropy and the classical probability.The structural entropy model of production systems is developed based on analyzing the characteristic of structure of production systems through disposing the model specially in order to calculate the model with more maneuverability.To solve the problem that it’s short of quantificational ways when the different operational status that is worked by the different production mode or production structure about production logistics system is evaluated,from the concept of fuzzy entropy,the operational entropy model based on the element of production system is developed according to the principle of the information entropy and the definition of order degree.The operational evaluation system of production system is established on the basis of the factor of production logistics system.As a result,this quantificational way to evaluate the orderliness of production structure is validated well and extends application area of this operational entropy model by an empirical study.Utility of complexity of manufacturing systems is deeply analysed and the result that the complexity influences manufacturing systems is illuminated and the corresponding strategy is proposed according to the relationship between the complexity of manufacturing systems and its utility fuction.Based on the Shannon entropy,the models of the structural entropy and the operational entropy of cellular manufacturing systems are developed and the cognizance of the states of manufacturing resources is also illustrated.Using the above ways developed,the research based on entropy theory of production logistics actualized fore-and-aft cellular manufacturing in some job shop is successfully accomplished.The empirical study indicates that the proposed models are feasible and effective.更多还原