Analysis of Reference Shaping Control for Improved Yaw Stability in a Steer-by-Wire Vehicle

Incorporation of electronic yaw stabilization in on-road vehicles can take many forms. Although the most popular ones are differential braking and torque distribution, a potentially better alternative would be the inclusion of a controller into the steering process. However, this is not often pursued in mechanically-coupled steering systems since the controller could work against the driver’s intentions creating potential challenges to safety. The growing adoption of steer-by-wire (SbW) systems now in autonomous/semi-autonomous vehicles offers an opportunity to simplify the incorporation of such steering-controller based assistance. Most current steering-assistance systems focus either on adaptive steering control (adaptive power steering and gear ratios) or on total steering control in autopilot functions (lane keeping control). Such steering-controllers (incorporated via SbW modality) can improve driving performance and maneuverability and contribute to the overall suite of active-safety vehicle systems. In this study, we introduce a new pure-feedforward (open loop) controller for the steer-by-wire system based on the concept of reference shaping control aimed at reducing the vibration/oscillation caused in vehicles during fast (evasive) maneuvers.