Vertical and Longitudinal Coupling Control Approach for Semi-active Suspension System Using Mechanical Hardware-in-the-Loop Simulation

When the vehicle is under braking condition in the longitudinal motion, the vehicle body will tilt due to the inertial force in motion. A high amplitude will result in uncomfortable feelings of the occupant, such as nervousness or dizziness. To solve the problem, this article presents an adaptive damping system (ADS), which combines the vehicle anti-pitch compensation control with the mixed skyhook (SH) and acceleration-driven-damper (ADD) control algorithm. This ADS can not only improve the vibration effect of the vertical motion for the vehicle but also consider the longitudinal motion of the vehicle body. In addition, a new damper mechanical hardware-in-the-loop test bench is built to verify the effectiveness of the algorithm. Compared with passive suspension, the vertical acceleration amplitude of the center of gravity (COG) of this algorithm can be decreased by 21.16% and 13.21% on average at different speeds on B-class road and C-class road, and the amplitude of pitch angle variation can be dropped by 28.82% on average at different decelerations with little change in the longitudinal acceleration of the COG. The waveform road is established to verify the effectiveness of the proposed algorithm for the vertical and longitudinal coupling motion. Compared with passive suspension and SH, the vertical acceleration amplitude of the COG can be reduced by 18.87% and 12.58% on average at different speeds on a waveform road, and the amplitude of vehicle pitch angle variation can also be decreased in different time periods under little difference for the longitudinal acceleration of the COG. The new test bench can verify the effectiveness of the control algorithm under the condition of no real vehicle, which enriches the test methods of algorithm development for a semi-active suspension vehicle and shortens the project development period.