A Motion Control Method Based on the Drive Mode Changing for the Autonomous Mobility With 4-wheel-steering System

This study presents a practical motion control algorithm and its implementation for an autonomous four-wheel- steering (4WS) vehicle. The proposed motion control algorithm utilized the mode-changing characteristics of a vehicle capable of independently operating front- and rear-wheel steering. A motion control algorithm incorporating a driving mode-changing strategy was developed based on the kinematic modeling of a 4WS vehicle for each driving mode. For 4WS vehicles, the kinematic characteristics of rotational motion vary according to the steering mode. To address this, an error-based control system was designed to ensure accurate tracking of target positions, and a control strategy was implemented that dynamically adjusts the steering mode based on the ratio of linear to angular velocities, determined by both position and orientation errors. In order to verify the validity of the proposed motion control algorithme, it was implemented on a 4WS vehicle hardware platform equipped with multiple positioning sensors and an integrated sensor fusion system.