Continental’s auto-driving software gets handover issue under control
Continental has developed an algorithm it calls Cruising Chauffeur. Running on the vendor’s Assisted and Automated Driving Control Unit (ADCU), the Cruising Chauffeur processes the data from the vehicle’s environmental sensors such as camera, radar and lidar. The software transforms these data into a 360° environmental model of the vehicle. This model is merged with the data from a high-resolution real-time road map that contains all moving and static objects as well as the course of the road and the traffic lanes. In this model, the vehicle’s position is determined and updated continuously. Thus, the algorithms can identify areas that can be safely used by the car within the boundaries of the traffic rules and the driving task and adjust the trajectory accordingly. This enables the Cruising Chauffeur to change lanes automatically; it also can pass another car and after completion return to the standard lane. These algorithms are designed for automated cruising on highways – a relatively simple task since typically the automatic driver does not have to handle oncoming traffic or pedestrians. All in all, this is what describes level 3 of autonomous driving.
But as soon as the vehicle is approaching If the end of the motorway section becomes closer, the vehicle has to request the human driver to take over. As long as the driver is closely monitoring the driving action in accordance with the requirements of level 3 automatedd riving, this is not a problem; being in a standby position, the driver can take over within a few seconds. The transition to level 4 of automated driving however is not as easy: In L4, drivers are allowed to devote themselves to other activities and even take a nap. Thus, they get out of the context and cannot drop in within a few seconds.
To handle this issue, Continental is using an interior camera that monitors the driver’s position and analyzes his direction of view. Smart algorithms detect the driver’s alertness and its capability to assume the task of driving. If the vehicle is approaching further the point where it is intended to leave the motorway and the driver is still not ready, the optical and acoustic warning signals are intensified. If the driver still does not show any reaction, the Cruising Chauffeur initiates the Minimum Risk Maneuver – which means that the computer either enters the emergency lane and brings the vehicle to a safe stop, or, if no emergency lane exists, it activates the hazard lights and stops where possible; if necessary it continues the ride at low (and decelerating) speed until it finds a suitable spot to stop.
The Minimum Risk Maneuver is also activated in the case of a technical failure. Towards this end, the software architecture provides for a monitoring level, the Safety Manager. This software identifies if one of the sensors fails and alerts the driver. In the meantime it can continue the driving task until the vehicle stops of the driver takes over. The Safety Manager software is based on the EB Tresos software framework from Elektrobit (EB).
“The capability to perform the Minimum Risk Maneuver is extremely important for autonomous driving, because it makes sure we can manage the car safely in any situation,” explains Ibro Muharemovic who oversees the Cruising Chauffeur project at Continental. “For such situations hitherto no solutions existed.”
To be able to safely handle the car even after the departure of single sensors, the Cruising Chauffeur is based on a redundant architecture. Part of the concept are separate data channels of different sensor types as well as the Safety Domain Control Unit (SDCU) as secondary data processing path besides the ADCU. The SDCU basically contains a separate and independent automation solution. In cases when the automation is confronted with conflicting rules or a sensor type is failing for technical reasons, the Minimum Risk Maneuver is activated. There is also an additional fall-back level for safety-critical systems such as brakes or steering.
In these properties, Continental’s ADCU has similarities with the zFAS central computer in the new Audi A8. However, the Continental system is not identical with the zFAS. By the time this article was published, Continental did not have answered eeNews’ questions about the microprocessors that power the ADCU and other technical details.
The ADCU with Cruising Chauffeur and Minimum Risk Maneuver will be available for series vehicles in 2020, Continental said.