Flavio Nardi

Vehicle Rollover Avoidance

This article presented an overview of vehicle rollover testing standard and control development. Government testing procedures are first described. Necessary vehicle state estimation for rollover control is then developed. An energy-based RDI is then investigated. Finally, a control strategy based on state estimation and the RDI is developed and verified in vehicle tests. A 1DOF vehicle model, together with standard inertia sensors for the stability control system, provides state estimation needed for RDI and rollover avoidance control.

Vehicle Sideslip Angle Estimation and Experimental Validation

This paper presents a comparison study of three different methods for the estimation of vehicle’s lateral velocity: one based on algebraic relationships, a second based on a dynamic observer, and lastly one based on kinematic equations. All methods are based on the implementation of an experimental nonlinear model that relates the front and rear axles’ lateral forces to their respective side slip angles. These nonlinear models include the effects of different surface coefficients of friction, and all three methods include a real time estimation of the surface coefficient of friction based on standard production sensors. Real time estimation performance of the proposed observers is compared and evaluated based on experimental implementation on a series production vehicle. Vehicle dynamic tests include highly dynamic maneuvers such as slaloms, single and double lane changes, fishhooks on test surfaces such as ice, snow, gravel, and wet/dry asphalt.Copyright

A Passive Progressive Damping Design for Ride and Handling

This article presents a method of synthesizing the non-linear compression damping curve to more effectively control the suspension behavior over roads that generate maximum wheel displacements, while maintaining good ride quality on normal roads. One degree of freedom (1DOF) nonlinear mechanical system is used to develop the optimal compression damping curve. All findings obtained using this 1DOF system are then confirmed using a quarter car model, full vehicle ADAMS model, and vehicle tests. The article addresses only the jounce portion of the damping curve which significantly influences the wheel displacement and shock tower load during a pothole event.Copyright

Vehicle State Estimation for Rotary Magnetic Selective Ride Control

This paper describes a method of vehicle state estimation using the kinematic relationships established based on the Kinematics and Compliance (K&C) test. The estimator relies on the suspension displacement sensors. Suspension velocities are estimated using discrete differentiation and specially developed nonlinear filter. Performance of the proposed estimator is verified through vehicle testing at different roads. The vehicle used in this study is a demonstration vehicle with prototype rotary magneto-rheological dampers.Copyright

Integrated Ride and Roll Control Using a Rotary Magneto-Rheological Damper

In this paper we discuss the development of estimation and control algorithms for the in-vehicle implementation of the Rotary Magneto -Rheological damper. Specifically, we address the estimation of sprung mass heave rate based on suspension position sensor measurements, the design of roll angle control based on lateral load transfer distribution concept, and the integration of these two with the wheel hop detection and control algorithms. The resulting integrated ride and roll controller is evaluated based on both vehicle dynamic response and ride quality objective criteria.Copyright