Assistance systems today
Vehicle systems that help the driver are nothing new. Ever since the 1960s, servotronic assistance for functions such as steering and braking systems have made driving more comfortable and convenient. The term “driver assistance systems” really only caught on with the increase in smart control. Anti-lock braking systems (ABS), electronic stability control (ESC), windshield wipers with rain sensors and power steering can be considered the first generation of DAS. But today’s radar and sensor systems are far more complex. In the English-speaking world, the more fitting term advanced driver assistance systems (ADAS) has become prevalent. This overview is intended to focus on advanced DAS, some of which merely warn drivers while others actively take part in driving.
Adaptive cruise control system
Typically abbreviated ACC, adaptive cruise control aptly describes the role of an optimized system for regulating speed. The well-known “automatic braking and acceleration” control function has been expanded with the ability to automatically maintain a specific distance from the vehicle ahead. The system obtains this information from one or two radar sensors in the lower part of the front of the vehicle.
The start-stop system is actually an extension of the adaptive cruise control
system. Together with a stop-and-go function, it provides the best service for relaxed stop-and-go driving in gridlock. This DAS brings the vehicle to a stop, switches off the engine and turns it back on after a short idle time to continue operating in the set regulating range. Most manufacturers use some combination of ACC and stop-and-go.
Emergency brake assist
Since 1996, Mercedes has had its brake assist system in series production vehicles. This system appropriately increases braking if the driver’s braking is sluggish. This system’s predictive capacity continues to improve with the incorporation of new sensors like radar and cameras. In step with the sequence during an impending collision, these smart DAS usually have a multiphase design. In the first phase, the driver receives a visual and/or audible collision warning. At the same time, the system builds up the maximum braking pressure and prepares the system for full braking. If the driver does not react, the system initiates the second phase itself (partial braking), and initiates full braking in the third phase if necessary. Starting from the first phase, the system continuously calculates the exact braking force required. If the driver reacts in one of the “pre-crash phases”, the force is exerted immediately; this occurs without any action on the driver’s part in phase 3, which can be especially beneficial to protecting pedestrians.
(Active) lane tracking assistant
Lane tracking assistants help drivers keep their vehicles in the same lane not only while simply driving straight, but also when optimizing steering input during quick avoidance maneuvers or in the event of gusts of wind from the side. One or more video cameras in the upper portion of the windshield provide the core information for this system. The system controller uses the lane’s side markings for orientation. If a distance drops below a defined value, the lane tracking assistant warns the driver. The active lane tracking assistant even introduces gentle corrective measures. This can include steering actions and/or targeted braking of individual wheels via the ESC. The driver can always counteract the actions taken by the system.