Methodologies Study And Corresponding Software Development For Knowledge-Driven Auto-body Structure Design

It is well known that automobile body design is the key factor of improving the quality of vehicle product and shortening the overall development cycle. The car body designer's concerns are not only the easily modification an but also the freely switching of the configurations and structure for specified design requirements. This study is basing on those concerns.This work is supported by following projects:1. The Great Industrialization Project of National Automobile Industry (No.2004-2563) of National Development and Reform Commission"CAD/CAE/CAM Software Platform of Car Body Digital Fine Design and Manufacturing"(FGGJ 2040).2. The National Outstanding Youth Foundation"The CAD expert system theory based KBE of stamping design and the research on the polymer forming theory and calculation method"(No.10125208).3. The National 985 Project of Jilin University"Automotive Innovation Platform". In this work, the theory and techniques of KBE (Knowledge Based Engineering) were applied to auto-body design for the first time. And the knowledge-driven auto-body structure design method was introduced in this thesis. Basing the KBE techniques, many quick design modules were developed for the car body designers, and those modules combine the parametric modeling techniques, optimization techniques and rapid design techniques. Those tools help auto-body designers to construct the car body parts quickly and efficiently, and show the value for improving the enterprise competivity.Knowledge Based Engineering (KBE) is an important embranchment of Artificial intelligence (AI) and the practice application of knowledge engineering theory, fundamentally about re-use. It concerns whether to be able to take advantage of any experience, expertise and other information relevant to each phase of the engineering life cycle of an end user product. The research of KBE included Knowledge Acquisition (KA), Knowledge Evolving (KE), Knowledge Representation (KR), Knowledge Reasoning, Knowledge Modeling and Knowledge Management (KM), whose pith is how to solve problems with knowledge. The difference between the Knowledge Based System (KBS) and the common programs is: the object which is operated by the former is knowledge, but the later is data. KBE design system can provide right knowledge and right tools at the right time. Therefore, KBE techniques used in the field of auto-body design will help engineers capture and reuse the knowledge, combine and optimize procedures between design and manufacture, establish and implement auto-body structure design practices successfully with higher quality.The concept of Prototype Part was proposed for the first time. The prototype part is an abstract of the auto-body detailed part in high level, and this prototype part exists as the KBE Model which embedded the special knowledge, expertise and engineering design rules. The knowledge-driven auto-body structure design system will be developed based on Prototype Part concept. That is to say the output of this software system is a product model combined with the expert knowledge, design process,engineering rules and so on,this kind of product model can realize the parameterization, automation, and intelligentization in auto-body product design. It will help the engineers to complete their design and development in shorter time with high quality.Regarding to the knowledge-driven body structure design, three methods named"Zone","Layer","sculpture"were proposed, then the auto-body design control structure with six layers including the Architecture, Drivers, Relationships, Zone Collector, Zone Models and Components was built.Taking the body side outer panel (four doors) as examples, the procedures based on KBE for building the parameterized model, the Prototype Part and the multi-layer control structure of body side with the"Zones and Layers"method were presented. The Body Side Door Opening Wizard (BSDOW) module was developed by coding with C++ language and the other multiple KBE development tools. The BSDOW will automatically create the basic shape of the door opening area of the body side. It provides a tool for body designers to create and modify the complex door opening part easily and quickly. And this newly developed process is an effective and feasible scheme that will also be used on other areas of body study to develop more design tools.Car door is the relatively important assembly. Car Door packaging is a very important scheme design task during the auto-body conceptual design phase. There are so many feature parameters and control hard points to be determined in the process of door packaging, while spatial relations and constraint conditions are complex, and implementation methods and evaluation indices are fuzzy. It results in the design scheme being multi-resolution, experiential and compromising. So how to process the car door packaging efficiently is a big problem to be solved immediately in the auto-body overall design cycle. So a lot of work that will be repeated is unavoidable. And these characters of multi-goals and multi-constraints decide the process of layout needs a lot of field experts'experience and knowledge as the guidance.The development of Knowledge Based Engineering for Door Accessories Package and Validation System which combine the expertise and knowledge based on UG/NX platform must improve the efficiency of the car door design. This system is divided into three major modules:B Pillar module, Hinge Location and Glass Drop module.The B Pillar module provides a preliminary design for the B pillar area of a door. It lets user validate the packaging that is dictated by the hinge, striker, check link, and electrical conduit locations that are part of the door design. The B pillar can also accommodate the seat belt retractor for the front seat. This function can be used at any time during the door design process to validate that whether the B pillar design meets the packaging requirements dictated by the current states of the front and rear door design.The Hinge Location module helps user add standard hinge components and position it to a door during the door design process. This module can also validate the door swings freely. The swing of the door may be simulated and the interferences may be detected.The Glass Drop module not only creates a parameterized modeling of the glass drop, in which users could modify and update the modeling by changing the parameters and rules, but also regenerates the glass surface (named barrel surface) by optimal algorithm. So engineers can simulate the process of glass dropping along the channels to verify the interferers between the glass and door accessories. As this system integrated the knowledge of body design and expertise, the engineer who is lack of experience can effectively complete the professional design for body-side and packaging door accessory in a short time.The new concept named Knowledge Driven Auto-body Development was proposed for the first time, which considered the theory of KBE and inspired from"Requirement Driven Design". The key technology including the UG/Open API, UG/WAVE, UDF, UG/KF, UG/UI Component for auto-body development based on UG/NX platform was summarized according to the requirement of software development life cycle.The visual design in front of the automobile was addressed especially at the hood visual design and a new stable algorithm for calculating the invisible zone of hood was proposed for the first time in this thesis. At last, the hood visual design tool named Hood Corner Invisibility was developed with the knowledge-driven automobile body key development technology.Indicator Packaging and Design module (named TT Indicator) as a product design template embedded knowledge was developed after in view of the automobile body accessories design and practices. All of the testing results show that, the body designer can dramatically reduce a significant amount packaging time and complete structure design easily and productively by using such a design template. Moreover, it provides a new way to help the KBE theory be applied to the field of auto-body accessories layout and the structural design.