Dynamic normal force control for vehicle stability enhancement

It is well understood that variations in normal force under the contact patch of pneumatic tyres effects the ability of that tyre to generate longitudinal and lateral forces. Normal forces self modulate when the vehicle corners, accelerates, or brakes, and its distribution, left to right and front to rear, can be affected by suspension design, anti-roll, and anti-pitch devices. This paper addresses the effectiveness of active suspension control to enhance vehicle lateral and longitudinal dynamics by modulating the normal force distribution at each corner of a vehicle. Normal force control is proposed for several scenarios including split µ roads and cornering over bumpy roads. It is shown that improved vehicle handling can result if normal force control is incorporated. Actuator and power requirements are assessed.