Diagnosis of defects on peeled veneers by the fuzzy expert system

单板剥落过程中的质量控制和生产控制是必不可少的环节。在单板剥落过程中，经验丰富、技术熟练的车床操作人员通常会利用他们的经验知识来控制单板车床的操作，从而生产出高质量的单板。当检测到剥落单板上的缺陷时，他们还能直观、即时地控制和调整车床的运行。因此，本研究的目的是收集与单板生产有关的熟练车床操作员的经验知识，并建立适用的诊断技术，以预测单板生产过程中缺陷的原因。我们相信专家系统是解决这类问题的强大而有用的工具。通过邮寄问卷的方式收集了车床操作人员通过自身经验获得的关于单板剥落的经验知识。问卷是由填充概率的原因，在百分比代表，影响贴面缺陷。我们向隶属于日本胶合板制造商协会的118家单板和胶合板厂发送了调查问卷。针对传统专家系统大多采用IF-THEN-explanation产生规则构建知识库的缺点，本文提出了一种新的专家系统，即模糊专家系统。通过对贴面质量的模糊性的理解，用模糊专家系统来表示贴面质量的定义和最佳操作条件的确定，使贴面质量的定义和最佳操作条件的确定更易于实现。在构建知识库之后，通过仿真考察了在假定的单板缺陷情况下，模糊专家系统对指示原因及其产生的概率的操作流程。在今后的研究中，为了建立系统的可靠性，在实际的剥离操作中对其进行验证是不可避免的。

The quality control and the production control in veneer peeling are invitable procedures. During the peeling of veneers, experienced and skilled lathe oprators usually control the operation of veneer lathes by using their empirical knowledges, to produce high qualities of veneers. They also control and adjust the operation of lathe intuitively and instanteneously, when they detect defects on peeling veneers.Therefore, objectives in the study were to collect emperical knowledges of skilled lathe operators concering with veneer production, and to build pu the diagnostic technique which is applicable, to predict causes of veneer defects in process. We believe that expert systems are powerful and useful tools to solve these kinds of problems.Empirical knowledges about the veneer peeling, which lathe operators acquired through their experiences, were collected by mailed questionnaires. The questionnaire was consisted of filling probabilities of causes, in percentage representation, affected veneer defects. We sent the questionn aire to 118 veneer and plywood mills affiliated to the Japan Plywood Manuf acturers' Association.Since the conventional expert system mostly builds its knowledge base by the production rule, IF-THEN-explanation, has some disadvantages, we developed a new expert system, i.e., Fuzzy Expert System. The difinition of qualities of veneers and the decision of the optimum operational condition is formulated easily and realistically if they are represented by the fuzzy expert system on the comprehension of their vaguenesses.After the construction of the knowledge base, we examined the operational procedures of the fuzzy expert system under supposed veneer defects to indicated causes and their probabilities to them through the simulation.In the future study, in order to establish the reliability of the system, its verification is inevitable in the real peeling operation.