Active kinematics suspension integrating Milliken moment method in the control logic

The idea behind the active kinematics suspension is to enhance its performance of vehicle dynamics. This includes improve steady and dynamic limit stability and faster transient reaction through optimized lateral and longitudinal dynamics. The driver’s benefits are: improved safety and higher driving pleasure. To achieve more control over the position of the rear wheels and thus the tire contact patch on the ground, the active suspension introduces one independent linear actuator at each rear wheel that controls the wheels’ camber freely. This paper will present the vehicle dynamics control logic methodology of a rear active vehicle suspension implementing the Milliken Moment Method (MMM) diagram to improve the vehicle stability and controllability, achieving gradually thefront and rear axle limits. A Multibody vehicle model has been used to achieve a high fidelity simulation to generate the Milliken Moment Diagram (MMD) also known as the CN-AY diagram, where the vehicle’s yaw moment coefficient (CN) about the CG versus its lateral acceleration (AY) is mapped for different vehicle sideslip angle and steering wheel angles. With the Moment Method computer program it is possible to create the limit of the diagram over the full range of steering wheel angle and side slip angle for numerous changes in vehicle configuration of rear camber wheels and operating conditions. The vehicle dynamics control logic uses the maps like a vehicle maneuvering area under different vehicle active configurations where vehicle’s control is most fundamentally expressed as a yawing moment to quantify the directional stability.