Active Control of Camber and Toe Angles to Improve Vehicle Ride Comfort

This paper is part of the European OWHEEL project. It proposes a method to improve the comfort of a vehicle by adaptively controlling the Camber and Toe angles of a rear suspension. The purpose is achieved through two actuators for each wheel, one that allows to change the Camber angle and the other the Toe angle. The control action is dynamically determined based on the error between the reference angle and the actual angles. The reference angles are not fixed over time but dynamically vary during the maneuver. The references vary with the aim of maintaining a Camber angle close to zero and a Toe angle that follows the trajectory of the vehicle during the curve. This improves the contact of the tire with the road. This solution allows the control system to be used flexibly for the different types of maneuvers that the vehicle could perform. An experimentally validated sports vehicle has been used to carry out the simulations. The original rear suspension is a Trailing-arm suspension. It has been modified via Adams Car. The simulations have been carried out using the same software in cosimulation with Simulink. The suspension has been tested through a Parallel Wheel Travel analysis and an Opposite Wheel Travel analysis. The maneuvers carried out have been two variations of Constant Radius Cornering, two variations of Fish-Hook and two variations of Swept-Sine Steer. A decrease in the vertical acceleration of the center of gravity has been achieved by controlling the Camber angle for maneuvers where a trajectory or rotation of the steering is imposed. The Toe angle control has allowed a decrease in vertical acceleration when a trajectory is imposed. In particular, the decrease of the Root Mean Square and the maximum absolute value have been obtained. These results demonstrate an improvement in Ride Comfort.