The Applicability of Hybrid Control to a Small Off-Road Vehicle Without a Differential

The use of controllable semi-active damping is considered by the vehicle dynamics community to be a cost effective and fail-safe method to reduce the ride comfort and handling tradeoff of a vehicle. This paper investigates the semi-active control of a suspension system for a 4-wheeled single seated off-road vehicle for both ride comfort and handling. The test vehicle is distinct with several characteristics that are not commonly observed on normal vehicles or addressed in existing literature. For instance, the absence of a differential in the driveline causes drivability and handling issues that are aggravated by increased damping. The suspension system contains controllable dampers and passive hydro-pneumatic spring-damper units. Passive damping is not entirely eliminated from the suspension, but the effect of various passive damping factors on the performance of the suspension is also investigated. Skyhook and groundhook control is implemented on a nonlinear, three-dimensional, 12 degrees of freedom simulation model to determine the achievable improvement in ride comfort and handling ability of the test vehicle. Simulation results show that reduced passive damping is capable of improving both the ride comfort and maneuverability of the test vehicle.