Abstract
KEYWORDS – three-axle vehicle, full vehicle model, hydro-pneumatic suspension, interconnected suspension system, ride comfort and handling ABSTRACT Performance of vehicles equipped with HP suspensions can be enhanced by exploiting certain possibilities such as the ease of interconnection of suspension units. By interconnecting HP suspension units on a vehicle, different suspension characteristics can be obtained. Commonly investigated two-axle vehicles allow only a limited number of practical interconnection possibilities. On the other hand, for vehicles with more than two axles, the number of practical interconnection configurations increases sharply. The objective of this study is the investigation of the design of interconnected HP suspension systems for a three-axle vehicle to improve vehicle performance using a realistic vehicle model.
A vehicle with three-axles forms a statically indeterminate system. Thus various solutions for the suspension forces at the static equilibrium can be obtained. Among these solutions, an optimum solution resulting in almost equal static distribution of the load among the axles is determined. Then interconnections in both the longitudinal and lateral directions are investigated. The proposed interconnected suspension system configuration is incorporated into the full vehicle model with eighteen degrees of freedom. The performance of the vehicle with the interconnected HP suspension system is examined by time domain simulations. Ride comfort performance is evaluated by random road simulations, and handling performance is evaluated by combined braking and cornering maneuvers. The results from the simulations are compared with the performance of the vehicle with the unconnected HP suspension system with regard to ride comfort and handling.
The proposed interconnected HP suspension system configuration is shown to improve handling performance in combined braking and cornering of the vehicle with slight performance degradation in ride comfort due to increased roll and pitch accelerations; while maintaining the ride comfort with respect to the bounce motion of the sprung mass.