Yaw Rate and Sideslip Angle Control through Single Input Single Output Direct Yaw Moment Control

Abstract

Electric vehicles with independently controlled drivetrains allow torque-vectoring, which enhances active safety and handling qualities. This paper proposes an approach for the concurrent control of yaw rate and sideslip angle based on a single input single output (SISO) yaw rate controller. With the SISO formulation, the reference yaw rate is firstly defined according to the vehicle handling requirements, and is then corrected based on the actual sideslip angle. The sideslip angle contribution guarantees a prompt corrective action in critical situations such as incipient vehicle oversteer during limit cornering in low tire-road friction conditions. A design methodology in the frequency domain is discussed, including stability analysis based on the theory of switched linear systems. The performance of the control structure is assessed via: i) phase-plane plots obtained with a non-linear vehicle model; ii) simulations with an experimentally validated model, including multiple feedback control structures; and iii) experimental tests on an electric vehicle demonstrator along step steer maneuvers with purposely induced and controlled vehicle drift. Results show that the SISO controller allows constraining the sideslip angle within the predetermined thresholds and yields tire-road friction adaptation with all the considered feedback controllers