Does Shared Mode Improve Steering and Vehicle Motions During Control Transition From Automated to Manual Driving in Real Passenger Car?

Abstract

Drivers occasionally need to resume vehicle control when an automated driving system (ADS) cannot handle a situation. However, a lack of driver readiness can prevent a smooth transition. For example, in an obstacle avoidance situation, a method to transfer the vehicle control based on the driver's input of the steering angle can be adopted where rapid steering operation by the driver is required immediately after resuming control. It was observed from the previous studies based on fixed-based driving simulator that the discontinuity in control due to a sudden disengagement of the control torque of the ADS resulted in steering instability. In addition, the previous studies had proposed a shared mode, in which haptic shared control (HSC) was placed between the automated and manual driving. It was demonstrated that steering stability could be improved through the shared mode. However, in the previous studies, the observation of steering instability and verification of HSC effectiveness of the shared mode were limited to fixed-based driving simulator experiments, in which there was no vehicle motion. In addition, for practical applications, a method using a torque sensor in the previous method is expected to be replaced by a more robust method, because it may introduce noise and the use of a lowpass filter leads to some time lag. Therefore, in this study, we developed a new control transition method that uses only the steering angle. We conducted experiments using a real car, in which the participants were instructed to resume steering control from the automated driving mode. The results demonstrate that the discontinuity in control during the control transition deteriorates the steering stability and vehicle motion, and the shared mode can improve them.

Authority Transfer According to a Driver Intervention Intention Considering Coexistence of Communication Delay

“…In previous studies, Sonoda et.al's research was conducted as follows. the research of Sonoda et.al was conducted on local vehicles [16]. It may not be sufficient in a system for remotely controlling autonomous vehicles.…”

“…However, assuming the technological advancements and sufficient safety of the ADS, it would be feasible to assume control during situations such as traffic congestion or parking, where the driver needs to take over. Therefore, in this study, in addition to the research of Sonoda et.al, we aim to provide criteria for tolerating certain levels of communication delay during control transfer and discuss potential strategies to address this issue [16]. When the driver intervenes in the ADS operation by using the steering wheel, the system shifts from Autonomous driving (AD) mode to shared authority mode.…”

“…There are many things to consider, such as erased lanes, broken traffic lights, damaged road surfaces, and sensor errors due to bad weather. To improve this problem, many studies are being conducted as a means to assist autonomous driving, such as monitoring, haptic, and teleoperation [12][13][14][15][16]. Teleoperation is used in many places such as Mars exploration robots and rescue robots [17,18].…”

“…One of the key functions when attempting to remotely operate a vehicle is to detect the intention of the remote operator to intervene in the operation. In the preceding study, the remote operator manipulates the steering to detect the driver's intention to intervene and transfer the control of the vehicle to the remote operator [16,28]. In addition, to compensate for the instability of system performance due to communication delays, there is also a study through a predictor model that predicts and compensates for delays [26,27,29,30].…”

A review of shared control in automated vehicles: System evaluation

“…Dynamic driving simulators appear to be more commonly used according to the present review. Additionally, as a milestone for shared control in automated vehicles, Sonoda et al presented the first driver study in a real car (Sonoda et al, 2022) ((Erlien et al, 2016 back in 2016 used an experimental platform). • Speed: Test speed ranges are growing, and tend to cover the full spectrum from urban (30 kph) to highway (120kph).…”