Active Drive Assist 2: the path to automated driving

• The smart entry into automated driving
• Cooperation between different systems
• Lane guidance and active steering assistant
• Intelligent distance control
• Stop safely with the emergency stop function

Setra is synonymous with coach safety. Many safety and assistance systems have made their debut in a Setra coach - the range of innovations extends from the retarder and anti-lock braking system to the Sideguard Assist cornering assistant, to name just a few examples. Setra's integral safety concept helps to proactively prevent accidents. It protects both passengers and the driver and takes account of vulnerable road users. The Setra TopClass is based on an advanced electrical/electronic platform. Among other things, it forms the basis for the latest generation of assistance systems. With these, the Setra TopClass sets standards in its segment and throughout the industry. The optional Active Drive Assist 2
(ADA 2) enables semi-automated driving in a coach for the first time.

The smart entry into automated driving

Accelerating, braking, maintaining distance, steering, lane keeping and even an emergency stop - the new ADA 2 represents a decisive step towards automated driving with coaches. By combining various assistance systems, the ADA 2 actively supports the driver in maintaining distance and staying in lane. The system can brake and accelerate the vehicle and keep it in lane by actively steering. To do this, it combines the functions of the individual systems in a unique way and thus already enables semi-automated driving in all speed ranges.

Cooperation between different systems

In the ADA 2, all assistance systems work hand in hand and support each other: for example, the ADA 2 acts in accordance with the Predictive Powertrain Control (PPC) specifications to ensure the most economical driving style possible. For longitudinal and lateral guidance of the vehicle, the system uses functional extensions based on the tried-and-tested Adaptive Cruise Control (ART) and Lane Assist. The ADA 2 also uses the same advanced radar and camera technology as the ABA 6 to detect traffic ahead. An emergency stop function has also been implemented. This brings the vehicle to a standstill by means of moderate, automated braking if the driver no longer reacts.

Lane guidance and active steering assistant

A key component of the ADA 2 is the active lateral guidance within the lane by the active steering assistant with an electric motor to support the hydraulic steering and the connection with the longitudinal guidance of the adaptive cruise control (accelerate/brake/maintain distance) through the fusion of radar and camera information.

With the active steering assistant, the ADA 2 also keeps the coach within the lane by means of continuous steering interventions when ART is activated. The driver can choose between three settings: Either the coach drives exactly in the middle of the lane or, depending on the width of the lane, slightly offset to the left or right by ten to 20 centimeters. The system thus significantly reduces the driver's workload by relieving him of a large part of the continuous small steering corrections required for lane keeping. Just like the ART, the active lateral guidance is active over the entire speed range of the coach from 0 to 100 km/h thanks to the active steering assistant. Prerequisite for the system: the lane must be clearly marked by lines on both sides.

A green steering wheel symbol in the central display indicates to the driver that the active steering assistant is assisting with lateral control of the vehicle. If the driver does not wish to use it due to the current traffic situation, they can deactivate the comfort assistance.

Intelligent adaptive cruise control

Even when ADA 2 is deactivated, the tried-and-tested adaptive cruise control continues to take over longitudinal control of the vehicle in conjunction with the predictive cruise control PPC. The adaptive cruise control brakes the coach before it gets too close to a vehicle in front and then accelerates it back up to the speed set by the driver. If necessary, the adaptive cruise control even brakes the coach partially to a standstill.

The ADA 2 was developed for driving on highways and highway-like roads, which is why a minimum lane width is required. If system limits are reached, e.g. unclear lane markings, lane that is too narrow or curve radii that are too tight, the system becomes passive. This is accompanied by a warning to the driver, signaled by a corresponding display in the cockpit.

Stop safely with the Emergency Stop function

Despite the assistance provided by the ADA 2, the driver always remains responsible. If the driver takes their hands off the steering wheel, a warning cascade is triggered in accordance with legal requirements (hands-off warning cascade). After 15 seconds, the assistance system issues a yellow warning, followed by a red display in the instrument panel and additional acoustic warnings at increasingly shorter intervals until a continuous tone sounds. If 60 seconds have elapsed since the start of the hands-off warning cascade without the driver putting their hands back on the steering wheel, the Emergency Stop function is activated. This initiates a speed reduction by removing the accelerator for one second. This is followed by speed reduction. The Emergency Stop function now takes over control of the vehicle within the system limits to keep it in the lane. The headlamps and the hazard warning lights system are activated 5 seconds before the end of the hands-off warning cascade to warn the traffic behind and the vehicle is braked to a standstill in a moderate manner. If the vehicle is stationary, the electric parking brake is activated and the hazard warning light system continues to flash. During the intervention of the emergency stop function, the driver is continuously informed by an acoustic continuous beep and a visual warning in the display about the emergency stop and the override option and can cancel the process by kickdown.