Methods in Research about Effect of Caster Angle on Vehicle Steering and Stability

Abstract

Caster angle is the angle between the king pin and the suspension system viewed from the side of a car. It is an important parameter in vehicle wheels positioning. Generally, positive caster angles improve the steering wheels’ returnability but increase the steering drag. The aligning torque increases as caster angle increases from zero to positive value, and goes to negative as caster angle has a negative value. There have been enough researches about the relationship between vehicle behaviour and wheel geometry parameters. Analytic methods are based on transforming a dynamical model to a mathematical model, and describing the vehicles’ motion with equations. With it some theories for optimization of caster angle were proposed. Using computer softwires ADAMS/CAR, more accurate models were built to simulate how vehicles act as parameters changes. This method could verify overall design of a vehicle’s structure. Experiment with physical models is a classical method, but it still useful today. These researches provide constructive ways in vehicle designing. This paper aims to summarize these existing research methods, show some researches with typical methods, and explain their advantages and shortages and explain their applicability.