A PID-Based Active Control of Camber Angles for Vehicle Ride Comfort Improvement

In the automotive industry, one of the principal issues is to ensure the comfort of vehicles as much as possible. High vertical accelerations of the vehicle body transmit undesired vibration, causing malaise to passengers. Car vehicles are subjected to vibrations induced by the road roughness or, during a curve travelling, by the roll motion. These factors contribute to generating the total vertical acceleration. The vertical acceleration due to the first factor can be decreased by correctly dimensioning the stiffness and damping of the suspension. In this paper, the active control of the camber angle of the rear wheels is proposed to reduce the vertical acceleration due to the roll motion. The proposed technique has been applied to a validated vehicle model developed in the ADAMS Car environment. The trailing-arm type rear suspension has been modified to include actuators functional for the control system implementation. The tracking of the variable vehicle body roll angle by rear wheels is allowed exploiting two PID controllers to improve the contact of the tire with the road and, therefore, the ride comfort. Two manoeuvres called Sine Steer and Fish-hook have been employed to validate the designed controllers. The RMS and the maximum value of the vehicle body's vertical acceleration decrease, demonstrating the employability of the proposed control system to improve ride comfort.