基于状态熵的制造系统结构复杂性建模与评价

针对现有结构复杂性建模方法存在的不足,在考虑中间缓冲区状态对制造系统状态影响的基础上,提出一种基于通用发生函数法和信息熵理论的非串行制造系统结构复杂性建模与评价方法,从系统角度对制造系统的复杂性进行测度。通过建立中间缓冲区的状态转移方程,定义缓冲区的状态,分析中间缓冲区状态对非串行制造系统各工位加工设备状态的影响,将原制造系统转化为等效系统;利用通用发生函数法描述各等效加工设备的性能及其发生概率,并将制造系统分解成若干并联和串联子系统,引入并联和串联复合算子求解整个系统的发生函数,得到系统的状态空间及其对应的概率空间;从系统角度出发,利用信息论中的信息熵模型建立非串行制造系统的结构复杂性模型。以某车间的非串行缸盖柔性加工线为例,验证该模型与评价方法的有效性。

Structural Complexity Modeling and Evaluation of Manufacturing Systems Based on State Entropy

The structural complexity modeling and evaluation method of non-serial manufacturing systems is brought out on the basis of considering the influences of the buffers’ states on the overall manufacturing systems to systematically measure the complexity of the manufacturing systems,aiming at the deficiency of the present structural complexity modeling method.The buffers’ states is defined through creating state transition equations of the buffers so as to analyze the influences of the buffers’ states on the machines in different work stations of non-serial manufacturing system,which in turn turns the original manufacturing systems into equivalent systems.The universal generating function is used to describe the performance and probability,and the manufacturing systems are divided into some parallel and serial sub-systems,followed by the solution of the systems’ generating functions with the parallel and serial composition operators introduced.The complexity model of non-serial manufacturing systems is established based on the entropy model of information theory from the angle of system.A non-serial machining line with four stages for cylinder heads is taken as an example to verify the effectiveness of the model and the validity of the evaluation method.