Improvement of Transient Response of Active Pitch Control for Preventing Passenger Falling over in Autonomous Shuttle

This study focuses on an autonomous shuttle (Robo-taxi with level 4 driving automation) with four-wheel drive in-wheel motors. During the social implementation phase of autonomous shuttles, ensuring the safety and comfort of passengers becomes a paramount concern due to the potential occurrence of in-vehicle accidents, even in the absence of a human driver. To address this issue, an Active Pitch Control (APC) method is used to automatically tilt the vehicle body to prevent passengers from falling over during deceleration and acceleration. The basic principle of APC is to distribute the driving/braking forces between the front and rear wheels to minimize the impact of inertial forces on the passengers. The authors proposed control system designs and demonstrated the effectiveness of the falling-over prevention mechanism in the previous study. However, the transient response of the APC to a tilting motion could harm passenger comfort. This study aims to improve passenger comfort by modifying the APC control method and performs numerical simulations to validate the improved approach on the autonomous shuttle. The goal is to prevent any adverse effects on passenger comfort resulting from the transient response of the APC to tilting motion.