2 KBE in CAPP system for stamping

2。1 KBE

Knowledge based engineering (KBE) is one innovative method of artificial intelligence for engineering design developed in the 1980s。 So far, there is no generally accepted and mature definition for KBE。 However, it is recognized that KBE is an intelligent method to resolve engineering problems, which can realize inheritance, integration, innovation and management of domain expert knowledge through the drive, multiplication and application of knowledge。 A knowledge-based system (KBS) is one that captures the expertise of inpiduals within  a particular field (the “domain”), and incorporates it and makes it available within a computerized application [15]。 The level of complexity of the tasks performed by such a system can vary greatly。 However, it can generally be said that while a domain expert would find them routine, they would be outside the capabilities of a person unfamiliar with the domain [16]。 KBE provides an open architecture and reuse ability of experience and knowledge, which can deal with multi- domain and multi-expression of knowledge, and can form an integrated environment。 A KBE application is further specialized, and typically has the following components of geometry, configuration,  and  engineering  knowledge:  –  Geometry  –  there  is  very  often  a    substantial

element of computer-aided design (CAD)。 Most of the software used to create KBE applications either has CAD capabilities built in, or is able to integrate closely with a CAD package。 – Configuration – this refers to the matching of valid combinations of components。 – Engineering knowledge – this enables manufacturing and other considerations to be built into the product design。 When a candidate application area requires a high degree of integration of the above elements, KBE is likely to be the best method for its integration。 KBE is sometimes termed rule-based engineering, as within the discipline, knowledge is often represented by rules。 These may be mathematical formulae or conditional statements, and although simple in concept, they may then be combined to form complex and powerful expressions。 KBE systems, on the other hand, are usually provided with specialized geometrical capabilities, with the ability to embed engineering knowledge within a product model。 The following examples of typical KBE applications demonstrate some of the considerable benefits to be gained from its use。

1) Lotus engineering。 This used the integrated car engineer (ICE) system in the design of the Lotus Elise。 ICE consists of a vehicle layout system, and modules to support the design of suspension, engines, power-train, wheel envelope and wipers [ 17]。

2) The Boeing Commercial Airplane Group。 This uses KBE as a tool to capture airplane knowledge to reduce the resources required for producing a design [18]。

3) Jaguar cars。 The company’s KBE group devised a system that reduced the time taken to design an inner bonnet from 8 weeks to 20 min [19]。

2。2 Problem to solve in a CAPP system based on KBE

A stamping CAPP system should deal with all knowledge including geometry, non-geometry, engineers experience, rules and criteria, results of tests and numerical simulation, or even successful cases, because of the complexity of automobile body panels。 The knowledge  is involved in perse fields, such as metal forming technology, metal forming mechanics, modern design methodology, numerical simulation technology, and artificial intelligence。 Accordingly, the CAPP system has to solve the problems with expression and application of all knowledge, and integration of all multidisciplinary design。 A CAPP system is essentially a set of instructions and guidelines on how to perform a complex procedure。 It details the inpidual sub-tasks, how they should be carried out, in what order, and how the work should be documented。 Furthermore, as system requirements change, new solutions tend to evolve from existing ones, so computer applications and their descendants can outlive the personnel involved in their initial development。 All in all, a stamping CAPP system for automobile panels based on KBE should readily solve the following problems: