The Vehicle Handling Model - A Symbolically Generated Vehicle Simulation Program Employing an Object-Oriented GUI

The Vehicle Handling Model (VHM) is representative of a new type of vehicle dynamics programs which can be easily used on a personal computer by vehicle development engineers. It consists of a simulation kernel which solves the vehicle equations of motion and a hypertext GUI which controls the model data input, execution, and post processing. The vehicle model has 5 DOF, including the vehicle lateral, vertical, yaw, pitch, and roll motions. The simulation also includes suspension compliance, a simple non-linear tire model, a wind gust model and a human driver model to provide realistic vehicle and steering inputs. The simulation program was generated by AUTOSIM which uses a high level description of the system to generate Fortran source code. The GUI allows an engineer to setup the model, run the analysis, and display the results with just a few clicks of the mouse. Versions of the program were developed for the Macintosh and IBM/Windows computers with the HyperCard and Toolbook programs respectively. This program development procedure allowed the simulation and GUI to be developed in a relatively short period of time. It can also be easily customized to suit particular applications. This paper describes the vehicle dynamics formulation, the GUI interface, and then illustrates a typical session using the VHM.