Fully electric vehicles with individually controlled drivetrains can provide a high degree of drivability and vehicle safety, all while increasing the cornering limit and the ‘fun-to-drive’ aspect. This paper investigates a new approach on how sideslip control can be integrated into a continuously active yaw rate controller to extend the limit of stable vehicle cornering and to allow sustained high values of sideslip angle. The controllability-related limitations of integrated yaw rate and sideslip control, together with its potential benefits, are discussed through the tools of multi-variable feedback control theory and non-linear phase-plane analysis. Two examples of integrated yaw rate and sideslip control systems are presented and their effectiveness is experimentally evaluated and demonstrated on a four-wheel-drive fully electric vehicle prototype. Results show that the integrated control system allows safe operation at the vehicle cornering limit at a specified sideslip angle independent of the tire-road friction conditions. left front wheel right front wheel left rear wheel right rear wheel front axle rear axle a generic discrete parameter front and rear semi-wheelbases longitudinal acceleration lateral acceleration maximum reference value of lateral acceleration process equation matrices in the extended Kalman filter stiffness parameter of the brush-type model of the tires damping ratio of the actuators error vector yaw rate error sideslip angle error first output singular vector, second output singular vector, singular vector matrix within the singular value decomposition of the sensitivity function longitudinal tire force lateral tire force vertical tire force static vertical load plant transfer function transfer function (with components G M z , r and G M z , β ) from the actual yaw moment to vehicle states transfer function (with components G p , r and G p , β ) from the reference yaw moment to vehicle states transfer function of the shaped plant transfer function (with components G δ , r and G δ , β ) from steering angle to vehicle states measurement equation matrices of the extended Kalman filter roll center height vertical distance between center of gravity and roll center identity matrix imaginary unit yaw mass moment of inertia half-length of tire contact patch slope for the increase of the reference yaw rate after the de-activation of the sideslip controller suspension roll stiffness control system matrix parameter of the yaw rate correction algorithm proportional gain yaw rate controller H ∞ optimal controller sideslip angle controller final controller formulation vehicle wheelbase vehicle mass reference control yaw moment actual yaw moment applied to the vehicle yaw moment contribution related to yaw rate control feedback part of M z,r feedforward part of M z,r yaw moment contribution related to sideslip control threshold of M z , β for activating the reference yaw rate ramp stability derivatives in the yaw moment balance equation yaw rate, yaw acceleration yaw rate output from the look-up table reference yaw rate reference vector worst reference direction, best reference direction, matrix with the worst and best reference directions according to the singular value decomposition Laplace operator or abbreviation for second closed-loop sensitivity function slip ratio time track width integral parameter input and output complementary sensitivity functions plant input first output singular vector, second output singular vector, singular vector matrix within the plant singular value decomposition vehicle speed input singular vector of the plant pre- and post- compensators extended Kalman filter process and measurement noises weighting factor for sideslip estimation state vector stability derivatives in the lateral force balance equation output vector slip angle and sliding limit slip angle sideslip angle, sideslip rate estimated sideslip angle sideslip angle estimated by the extended Kalman filter values of sideslip angle and sideslip rate at the equilibrium for the passive vehicle values of sideslip angle and sideslip rate at the equilibrium for the controlled vehicle in Sport Mode sideslip angle estimated through the integration method activation parameters of the sideslip controller peak value of sideslip angle reference value of sideslip angle sideslip control activation threshold sideslip threshold camber angle steering angle steering wheel angle load transfer induced by the aerodynamic forces load transfer caused by lateral acceleration reference yaw rate correction and corresponding threshold time step offsets between the nominal activation thresholds and the actual activation and deactivation thresholds in the relay activation scheme of the sideslip controller maximum robust stability margin parameter of the brush-type model of the tyres actual and estimated tire-road friction coefficient minimum and maximum singular values matrix resulting from the singular value decomposition of the plant frequency natural frequency of the actuators cut-off frequency of the reference yaw rate angular wheel speed 
Enhancing vehicle cornering limit through sideslip and yaw rate control