Research on Truck Active Suspension Systems Effectiveness with Auxiliary Hydraulic Cylinders

The vehicle's body oscillation when traversing bumps not only causes driver discomfort but also negatively impacts the quality of the transported cargo. Consequently, numerous research studies have been conducted to improve suspension system characteristics with the goal of enhancing the vehicle’s ride comfort and body stability. The majority of them have shown that equipping trucks with an active suspension is the most effective technical solution for ensuring comfortable working conditions for driver and cargo safety. This paper focuses on modeling and controlling an active suspension system for a truck in specialized simulation software, followed by evaluating its effectiveness compared to traditional passive suspension. In particular, the paper presents a quarter-vehicle suspension model integrated with an auxiliary hydraulic cylinder submodel controlled by a PID controller. The input parameters of the simulated suspension system were determined during full-scale experiments with real vehicles in laboratory and road conditions. To confirm the adequacy of the proposed mathematical model an experimental scenario was designed for measuring the vehicle body's oscillation parameters when traversing a step bump in the “passive” suspension control mode. After validating the model, the study proceeded to investigate the effectiveness of the active suspension system with the auxiliary hydraulic cylinder pressure PID control and compare the obtained results with the “passive” control option of the suspension system. The survey results indicate that the active suspension system, in conjunction with the PID control algorithm, significantly improves key performance metrics of the system. Specifically, the study found a reduction in oscillation damping time from 1.61 sec to 0.92 sec, a 16.7 % decrease in maximum amplitude of vehicle body oscillation and a substantial 61.5 % average reduction in vehicle body oscillation acceleration. On the other hand, in the active suspension system, the damping ratio also improved by about 5.8 % (from 0.260 to 0.245). These findings underscore the effectiveness of the active suspension system, as developed in this research, in enhancing the overall performance of the vehicle in terms of stability, safety, and ride comfort.