A compact magneto-rheological tactile feedback device with axial comb-shaped channel for steer-by-wire systems

Steer-by-Wire (SbW) systems eliminate the mechanical linkage between the handwheel and roadwheels, necessitating artificial tactile feedback to restore steering feel. This paper focuses on the design, optimization, and experimental validation of a compact magneto-rheological torque feedback device (MRTFD) intended for SbW applications. To accommodate the elongated axial geometry and severely limited radial envelope of SbW steering columns, an axially oriented comb-shaped MRF channel configuration is developed. This architecture enhances magnetic field utilization and load-carrying capability while maintaining a low off-state torque, enabling a wide controllable dynamic range within stringent geometric constraints. A constrained multi-objective optimization framework is employed to balance dynamic torque range and energy consumption under a prescribed maximum activated feedback torque constraint. The optimized design is subsequently fabricated and experimentally characterized, showing close agreement between measured and simulated torque responses. Furthermore, the prototype is integrated into an SbW steering test rig and evaluated under a feedback control scheme that combines a PID controller with inverse-model feedforward compensation. Experimental results demonstrate accurate torque tracking over various steering rates, thereby highlighting the feasibility and effectiveness of the proposed MRTFD for future SbW steering feedback applications.