Search Results

This article presents a methodology to apply Model-Based Design to develop and automatically optimize vehicle stability control systems. Such systems are employed to improve the dynamic rollover stability of Sport Utility Vehicles (SUVs). A non-linear vehicle model, representative of a midsize SUV, was built in CarSim®. This vehicle model is used in Simulink® to design a control system that reduces the risk of rollover. Optimization methods are then used to automatically adjust controller parameters to meet the system specifications that ensure the stability of the vehicle. Cosimulation between the two software packages enables rapid design and verification of control algorithms in a virtual environment. The results of the simulation experiments can be visualized through a 3-D animation of vehicle motion. The control system is adapted for the specific vehicle model, enabling it to remain stable under standard test conditions.

In 2008 the Australian National Transport Commission (NTC) published a reference document titled Performance Based Standards Scheme - The Standards And Vehicle Assessment Rules [1]. This document describes a series of testing requirements known as Performance Based Standards (PBS) to be used for certifying truck configurations acceptable for the Australia highway system. The PBS specification allows for both in-vehicle testing and numerical analysis using simulation tools such as TruckSim [2]. Several of the PBS tests require a Low-Speed 90° Turn, used to measure tracking behavior and tire friction utilization. This test presents an unusual simulation challenge because the driver is required to closely track a path with the outer sidewall of the outside front tire. A human driver must learn the response of the vehicle in order to steer it accurately through the test.

Some of the best teaching methods are laboratory courses in which students experience application of the principles being presented. Preparing young engineering students for a career in the automotive industry challenges us to provide comparable opportunities to explore the dynamic performance of motor vehicles in a controlled environment. Today we are fortunate to have accurate and easy-to-use software programs making it practical for students to simulate the performance of motor vehicles on “virtual” proving grounds. At the University of Michigan the CarSim® vehicle dynamics simulation program has been introduced as such a tool to augment the learning experience. The software is used in the Automotive Engineering course to supplement homework exercises analyzing acceleration, braking, aerodynamics, and cornering performance. This paper provides an overview of the use of simulation in this setting.