Thermomechanical Model Predictive Cascade Control for Blended Braking of an IWM Vehicle

The paper proposes an online control algorithm that optimizes the distributions of the electric and hydraulic torques to each wheel of an In WheelMotor (IWM) vehicle. The torque allocation strategy considers the driver's requests and the vehi-cle's longitudinal and lateral dynamics in relation to the available driving and braking torques of the IWMs and the hydraulic brakes. The blended braking action considers the dynamics of the actuators, the adherence limits, and the thermal limits of the electric motors. The objective of minimizing the energy consumption of the system has been achieved by implementing a linear MPC cascade controller aimed at computing the minimum effort of the actuators based on a linearized model of the vehicle system, on the thermal model of the electric motors, and on the dynamics of the hydraulic braking system. The effectiveness of the control action has been verified through different simulation scenarios, evaluating the full potential of the algorithm even in hard driving and braking maneuvers.