Improvement of High-Speed Vehicle Vertical Ride Comfort with Semi-active Primary Suspension

With the trend of car-body light-weighting, car-body structural vibration is imposing a new challenge to the vertical ride comfort which, however, is difficult to be improved by passive suspension components. Semi-active primary suspension (SAPS) is studied in this work to improve the vertical ride comfort with special attention on the suppression of car-body first bending mode. At first, a coupling effect between car-body bending mode and bogie pitch and longitudinal vibrations is analyzed. Then a simplified vehicle model is established to represent the vehicle dynamic behavior, showing a good agreement with a detailed multibody vehicle model in SIMPACK, integrated with the finite element model of the car-body. Skyhook controller is applied in the SAPS, capable of mitigating vibration from the car-body bending mode. LQG controller is also developed, showing further reduced vibration not only related to the first bending mode but also in a lower frequency range associated with vibrations due to rigid modes.