The application of an adapitive suspension approach in vehicle handling

• Main Author: Boulos, Alfred R.
• Published: Coventry University 2008
• Subjects: 629.2
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.495454

Vehicle handling is an area where vehicle manufacturers constantly seek improvement. However it has been traditionally regarded as an area where improvement is seen to come at the cost of vehicle ride quality. Even though much work has been done in this area, only a limited number of studies have considered decoupling the body roll effects on wheel camber change, thus improving roadholding capabilities. Whilst several of the adaptive or active suspension systems, control damping effects to improve ride, vehicle manufacturers also now use electronic systems to improve vehicle stability and handling characteristics. Some of these may even include suspension systems that maintain or adapt wheel camber. Although current examples ofsuch suspension systems aim to either reduce body roll or camber change, they cannot meet both conditions simultaneously during independent wheel travel. ill order to understand the true benefits of camber control, a suspension system that can have such camber control activated and deactivated, should be considered for comparative purposes. Such study would be quite expensive and a time consuming challenge if it were to be done in the real world, especially if the benefits and feasibility are not yet clear today to help justify any funding requirements. For this reason a suspension concept is proposed, investigated through computer modelling techniques and is outlined In this report. The concept consists ofhaving the upper control arm of a suspension system adapt its length, with the use of intelligent . hydraulically actuated control systems, thus maintaining the set wheel camber angle, during independent wheel travel. A .literature survey has been conducted, investigating previous work that has been . carried out in this area of research. An initial study has also been conducted in the available technologies relating to the proposed concept. Computer modelling techniques have also been acquired and implemented by the author, to produce a fully functional virtual prototype of a vehicle, using a selected multibody systems (MBS) program. However, MBS tools often do not include the means to define and solve complex hydraulic and control system effects. Therefore investigations into the best approach. of solving integrated MBS models with complex system models were required and developed. Several simulations, including step-steer, sme, swept-sine and ISO-lane change manoeuvres have been run and validated on a benchmarked vehicle. These were later compared to results of simulations with the proposed concept implemented on a modified vehicle model. The unique approach developed to solve the combined MBS and complex hydraulic and control systems, has proven significant benefits for vehicle dynamics analysis, whilst the above mentioned concept of maintaining camber angle has proved to be quite feasible with some benefit to vehicle handling.