Authority transfer method from automated to manual driving via haptic shared control

Abstract

As defined by the Society of Automotive Engineers (SAE), drivers are required to resume control from an automated driving system (ADS) in automated Level 2 and 3 driving when requested by the automated system. For example, the driver must resume manual driving control when the functional limitations of the ADS are approaching or have reached. In addition, he or she may also resume manual driving control whenever he/she realizes the functional limits of the system are approaching, or when an ADS malfunction is imminent. In such cases, it is necessary to smoothly transfer driving control to the driver, even when immediate steering actions are needed. Accordingly, this research proposes a method for smoothly transferring authority of steering control from the ADS to the driver in situations where drivers are required to perform quick steering actions. The method is based on a haptic shared control technique that can adjust the strength of the steering control by the ADS. We applied our method to a small electric vehicle and conducted experiments. It was demonstrated that the driver's intention to take over the control could be detected quickly only from the driver's steering operation. It was also suggested that aggressive steering behavior was suppressed with the proposed gain tuning technique, even in cases where the driver was required to engage in engage in immediate steering actions after resuming control.