A Modeling Approach on Modeling of Nonlinear System for Functional Development of Automobile 2001-01-0638

To shorten the term of automobile development, recently the numerical experimental systems are focused as the compensation methods of real experimentations. These systems are based on the accurate modeling method, and simulate actual motions of mechanism sufficiently accurate to predict the results of actual experimentation and to be the alternative of it.

The automobile mechanisms involve various nonlinierity in its motion because of its complex mechanic structure, fluid existence and thermo utilization nature. Therefore the modeling method applied to automobile mechanism is particularly required the accuracy on nonlinear action.

There were mainly two modeling method well known. One is the Bondgraph method which simulate energy flow of dynamic system. As the all physical phenomenon is recognized as embodiment of energy behavior, this method is to be excellent in accuracy as calculation of physical phenomenon. However this method is generally poor at representing complex mechanism in detail because of its rough notation. Another method is commercial software widely spread. This method has notation code consist of the components represent simple mathematical calculations, therefore is adaptable for various phenomenon. However this method is regardless of energy flow. This means incomplete modeling of physical phenomenon. In this method, a phenomenon may be represented as the change of one visually measurable value. It will be insufficient to analyze the physical phenomenon particularly if the phenomenon make the supply or loss of energy, it frequently occur in nonlinear process.

To overcome this dilemma, the new method, Functional Modeling Method is formerly proposed. This method has detailed notation code like conventional commercial software, and also is regardful of energy flow.

In this paper, the solution of how to describe the nonlinear phenomenon precisely without physical abstraction is explained. Furthermore the examples of solution of modeling about actual automobile mechanisms are presented.