This paper presents an integral sliding mode (ISM) formulation for the torque-vectoring (TV) control of a fully electric vehicle. The performance of the controller is evaluated in steadystate and transient conditions, including the analysis of the controller performance degradation due to its real-world implementation. This potential issue, which is typical of sliding mode formulations, relates to the actuation delays caused by the drivetrain hardware configuration, signal discretization, and vehicle communication buses, which can provoke chattering and irregular control action. The controller is experimentally assessed on a prototype electric vehicle demonstrator under the worst-case conditions in terms of drivetrain layout and communication delays. The results show a significant enhancement of the controlled vehicle performance during all maneuvers. Index Terms-Actuation delays, experimental tests, integral sliding mode (ISM), torque-vectoring (TV), yaw rate control. NOMENCLATURE a, b Front and rear semi-wheel bases. a x , a y Longitudinal and lateral vehicle accelerations. c F , c R Front and rear track widths. c hs , k hsHalf-shaft torsion damping coefficient and torsional stiffness. f , h, n, k Known functions of the states (x), the contribution due to uncertainties and disturbances, the term multiplied by the control input, and the yaw acceleration contribution due to lateral tire forces and selfaligning torques (SAT), respectively.

Abstract-Individually-controlled powertrains of fully electric vehicles present an opportunity to enhance the steady-state and transient cornering response of a car via continuously-acting controllers and enable various "driving modes" to be available. This study investigates the associated potential for energy savings through the minimization of power losses from the motor units via wheel torque allocation. Power losses in straight-ahead driving and a ramp steer maneuver for different motor types and under different wheel torque allocation schemes are analyzed in an offline simulation approach. Significant reductions in motor power losses are achieved for two motor types using an optimization scheme based on look-up tables of motor loss data. Energy loss minimization cannot be achieved through a direct quadratic approximation of the power losses.

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Fully electric vehicles with individually controlled motor drives allow the continuous actuation of direct yaw moment control in order to enhance vehicle safety and the handling performance by achieving a set of reference understeer characteristics. For applications on real vehicles, the control structure must provide ease of implementation, robustness and tunability. This paper discusses an integral sliding mode formulation for torque-vectoring control, which fulfils these requirements. The control structure is presented with reference to the vehicle cornering performance objectives, the motivation for integral sliding mode control and the selection of the controller parameters for stability and chattering avoidance. Six different manoeuvres are simulated for an in-wheel electric motor drivetrain layout. The results show that integral sliding mode control has significant benefits over a more conventional control method based on a combined feedforward and proportional-integral-derivative controller. The integral sliding mode controller does not require fine tuning of a feedforward control action and is characterised by superior tracking performance and disturbance rejection properties. Integral sliding mode for the yaw moment control of four-wheel-drive 389