An alternative semiactive control method for sport utility vehicles (original) (raw)

2002, Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering

Many investigators have predicted that the performance gains attainable with a semiactive suspension are comparable with those possible with a fully active suspension. To achieve this, one of the crucial factors is the method by which the damper is controlled. This study is an investigation, through simulation, into the eVectiveness of a number of basic control strategies in controlling vehicle dynamics, particularly roll. In addition, this study examines the eVect of changing the vehicle mass on the eVectiveness of selected semiactive control policies. The model represents a sport utility vehicle (SUV ), a class of vehicles that regularly sees widely varying vehicle weight and exhibits undesirable levels of vehicle roll. In this study, a four-degree-of-freedom vehicle roll plane model is subjected to a variety of road-and driver-induced inputs, and the vehicle response with diVerent semiactive control policies is characterized. The semiactive control policies investigated are tuned and modi ed such that the best possible performance with each is attained, and then they are compared. In addition, the eVect of variations in vehicle weight on the performance of each semiactive control method is investigated. In this investigation, two basic skyhook control strategies are investigated, and two modi ed strategies are proposed. It is found that the performance achievable with each of the diVerent control strategies is heavily dependent on the properties of the controllable damper. The properties that were particularly important were the upper and lower levels of force that the controllable damper was able to apply. The controllable dampers were tuned for each control system, and the results indicate that a velocity-based skyhook control policy, in conjunction with force control, is most eVective at controlling both road-induced vibration and driver-induced roll. Furthermore, the results show that such a control policy is relatively insensitive to variations in vehicle weight.