An alternative semiactive control method for sport utility vehicles

摘要

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 effectiveness of a number of basic control strategies in controlling vehicle dynamics, particularly roll. In addition, this study examines the effect of changing the vehicle mass on the effectiveness 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 different semiactive control policies is characterized. The semiactive control policies investigated are tuned and modified such that the best possible performance with each is attained, and then they are compared. In addition, the effect 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 modified strategies are proposed. It is found that the performance achievable with each of the different 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 effective 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.