New Integrated Full Vehicle Suspension System for Improvements in Vehicle Ride Comfort and Road Holding

Abstract
The integration of electric motors into the wheels of electric vehicles (EVs) increases the unsprung mass which leads to a deterioration of both the ride comfort performance and the road-holding ability and requires then low- and high-frequency control, respectively. In this article, a new integrated full vehicle suspension system is proposed to improve ride comfort and road holding simultaneously. We are seeking to design a hybrid fuzzy system to control the suspension damper and an intelligent proportional integral derivative (PID)-fuzzy to control the in-wheel (IW) Dynamic Vibration Absorber (DVA). To achieve an acceptable vibration performance, the parameters of the DVA system are optimized by using sequential quadratic programming (SQP) algorithm. To validate the ride comfort performance and road-holding ability of EVs driven by four in-wheel motors (IWMs), the proposed strategy of vibration control, based on the combination of the hybrid fuzzy system and the intelligent PID-fuzzy DVA, has been implemented on Matlab/Simulink software. The simulation results under a bump road profile show that the designed integrated full vehicle suspension system is better than other suspensions and satisfies the four main suspension performances.