Risk Assessment Of Machining Center Based On Improved Multicolor Set Theory

CNC machine tools are the enabling equipment for the development of emerging hightech industries and cutting-edge industries.As a typical CNC product,machining centers are widely used due to their strong flexible processing capabilities,but due to the high degree of functional and mechanical coupling between component units Features such as high-density connections provide the possibility for fault propagation.Even if the smallest faults cannot be eliminated in time,they will affect the entire production process and cause significant losses to the enterprise.Therefore,it is of great practical significance to consider the propagation of faults for risk assessment of machining centers.The thesis takes a certain type of domestic machining center as the research object,integrates graph theory,statistical theory.Uses Copula function to model the failure transmission probability between subsystems,and uses DEMATEL,ANP,rough set and information entropy theory to evaluate the impact of subsystem failures,and introduces accordingly The theory of polychromatic sets is improved and the Boolean matrix is improved,the failure risk assessment model is established and the effectiveness of the method is verified by Petri net simulation.The main research contents are as follows:(1)Divide the subsystems according to the structural and functional principles of the machining center,combine the fault information to carry out the correlation analysis of the subsystem failure and the failure probability modeling,use the subsystem as the node and the fault transfer relationship as the directed edge to construct the fault transfer directed graph;Copula function is used to construct the associated failure probability model of the failurerelated subsystems,combined with the failure probability of the initial subsystem node and the concept of conditional probability,to solve the failure transmission probability between the related failure subsystem nodes of the machining center.(2)Based on the fault transmission directed graph,the DEMATEL method is used to analyze the fault influence relationship of the machining center subsystem and establish a fault transmission hierarchical model,consider the failure mode transmission relationship to construct an ANP network model;introduce 1-9 scale to the fault associated subsystem node Perform fault impact scoring,call the "Computations" module in SD software to solve the fault impact super limit matrix to achieve subsystem fault impact evaluation;discretize fault information to form a fault impact evaluation knowledge decision table,and use rough set reduction conditions to complete the attribute dependency set division,Consider the information degree of the subsystem under different condition attributes,and evaluate the influence of the subsystem failure by comparing and calculating the mutual information change after deleting the attributes of different subsystem nodes;according to this,the theory of minimum information entropy is introduced,and the two types of failure effects are combined to realize the failure of the machining center.Comprehensive assessment of impact.(3)Considering the risk transmission of failure modes,constructing the risk transmission model of subsystem nodes by integrating the directed graph of failure transmission,the probability of subsystem failure transmission and the comprehensive influence degree of failure;applying multicolor set theory and improving it,taking the risk of subsystem nodes as Basically,the risk transfer between nodes is "color",a risk assessment model is established to evaluate the risks of the processing center subsystem nodes,identify critical risk paths,and use Petri net simulation software to verify the effectiveness of the method.