Semiactive Fuzzy Logic Control for Heavy Truck Primary Suspensions: Is it Effective?

Using a simulation model, this study intends to provide a preliminary evaluation of whether semiactive dampers are beneficial to improving ride and handling in class 8 trucks. One of the great challenges in designing a truck suspension system is maintaining a good balance between vehicle ride and handling. The suspension components are often designed with great care for handling, while maintaining good comfort. For Class 8 trucks, the vehicle comfort is also greatly affected by the cab and seat suspensions. Dampers for passive suspensions are tuned "optimally," using various metrics that the ride engineer may consider, for the condition in which the truck operates most frequently. In recent years, the popularity of semiactive dampers in passenger vehicles has prompted the possibility of considering them for class 8 trucks. In this study, the vehicle safety versus ride comfort trade-off is studied for a certain class of suspensions with semiactive fuzzy control. The proposed semiactive fuzzy control is based on the control policies that are commonly known as skyhook and groundhook. After describing the mathematical details of the proposed semiactive fuzzy control, it is applied to a roll-plane model of a heavy truck in order to compare its performance with conventional passive suspensions. The results of this study show that although semiactive suspensions with fuzzy logic control can improve vehicle roll, they could result in larger peak accelerations and a harsher ride.