Integrated Expert System Development Environment With an Automatic Verification Feature: An Application To Grinding Process

Abstract

The concerns of this Master degree project are the implementations of an expert system development environment and an application to manufacturing. The environment is given the name of IDEA (Integrated expert system Development Environment with Automatic verification feature), and it integrates an expert system shell with a rule base verification facility and a rule base builder into a single program. The interface of IDEA has the look of a general purpose computer language. The knowledge bases referenced by IDEA consist of LF-THEN rules with the syntax of Object-Attribute-Value (O-A-V) triples and confidence factors. An application is developed for grinding chattering diagnosis problems using the IDEA. The verification facility of IDEA realizes the main functions of CHECK, a verification tool, developed by T. Nguyen et al, 1987, so that it can identify some major problems of inconsistency and incompleteness. Different from CHECK, IDEA uses a unique approach based on rule tree algorithm to check for some logic problems in a rule base. IDEA also has the ability to draw the rule tree on a computer screen. This report discusses the problems of inconsistency and incompleteness in detail, including the influence of introducing confidence factors. Some problems identified in this report are not reported before. The rule base builder of IDEA uses some techniques that can greatly reduce errors in a rule base during its input phase and greatly speed up the input work. First, the builder uses templates for rule input to eliminate the possible syntax errors of rules. Second, it uses an O-AV file for declared O-A-V triples. By checking the O-A-V file and the O-A-V triples used in the rule base, the problems of illegal O-A-V triples and unreferenced O-A-V triples can be identified. Finally, it has the ability to automatically generate the ask-part of the rule base, so that no errors will exists in the ask-part and the input work can be efficient. Grinding chattering is a kind of abnormal phenomenon in a grinding process, which greatly degrades the surface quality of the workpiece ground. The grinding chattering diagnosis rule base gives complete answers for the causes of chattering for external cylindrical grinding. This report describes the rule base development work and its related grinding knowledge.