Active geometry control suspension system for the enhancement of vehicle stability

Abstract

The active control of suspension geometry has historically been a challenging perspective for chassis teams of worldwide automakers. Manufacturers and suppliers have offered different solutions, but few have succeeded in combining a marked improvement in handling performance, low-energy consumption, simplicity, and low cost. The new and revolutionary approach of an active geometry control suspension (AGCS) reinvents the possibilities of rear-suspension active toe control. This system employs the use of the complexity of a rear multi-link suspension, and a clever design layout to minimize the energy use. Additionally, because of an efficient control logic strategy, the vehicle-handling performance and stability are substantially improved. The system is the most successful in controlling vehicle transient situations initiated mainly by aggressive lane-change manoeuvres at medium to high speeds. This paper presents the most relevant actions of the development process of the AGCS. The use of different evaluation methods and accurate measurement equipment was crucial for optimization of the system. The methods presented combine subjective evaluations in different road conditions (icy, wet, and dry asphalt), suspension kinematics and elastokinematics characterization, and objective road measurements using dynamic wheel position measurement equipment. Finally, a comprehensive summary of the handling-test results are explained, which outline the efficiency of the system, and its influence on the active safety level of the vehicle.