Enhancing Steer-by-Wire Systems with an Integrated E-Motor and MR-Brake Actuator – Feedback Control Strategy

This study introduces an innovative control strategy for a steer-by-wire (SbW) force feedback actuator, tailored for automotive use. The actuator integrates a direct drive electric motor and a magnetorheological brake (MR-brake) within a streamlined, compact design. This electric motor delivers torque essential for the desired steering feel and ensures swift responsiveness. Concurrently, the MR-brake, noted for its compactness and energy efficiency, contributes passive damping and robust end-stop torque capabilities. The synergistic use of these components allows for a smaller and more resource-efficient electric motor design. A critical aspect of this strategy is the implementation of a torque splitter, essential for replicating the steering feel associated with Electric Power Steering (EPS) systems. This splitter distributes the required feedback torque between MR-brake torque and e-motor torque, ensuring high fidelity and consistent stability across a range of vehicular dynamics and maneuvers. Notably, maintaining a subjectively satisfying steering feel under conditions where torque proportions vary between actuators presents a significant challenge. The proposed actuator design, with its focus on performance, safety, and reliability, is particularly well-suited for advanced SbW systems demanding high standards in these areas.