A key part of being able to diagnose a problem with advanced driver assistance systems (ADAS) is understanding how the system works. Knowing what is happening inside the system will help you properly diagnose why the system may be failing. This will prevent replacing parts that are not causing the system issue. In this first ADAS article, we’ll look into four key systems: 360° Camera, Adaptive Cruise Control, Adaptive Lighting and Blind-Spot Detection. Subsequent articles will take deep dives into these complex ADAS systems and their repair considerations:
360° camera system
The 360° camera view system utilizes several cameras located around the vehicle to create a “bird’s eye” view of the vehicle. Many of the inputs have multiple functions and talk to more than one ADAS. This means that if one of the inputs fails, it might influence more than one ADAS. In fact, depending how the vehicle is equipped, the ADAS can take over and control many different functions and systems of the vehicle. This includes some drivability functions, like braking and steering.The normal 360° system is comprised of four cameras. The exact location of the cameras can vary, but there is generally a camera in the front bumper or grille, under the side mirrors, and in the rear of the vehicle. The camera in the rear of the vehicle can be located in the liftgate, tailgate, deck lid or rear bumper. There are also more advanced 360° camera view systems that use a camera on each side of the front bumper cover, or multiple cameras for the rear view. These additional cameras can give additional views, such as a view of the intersection that is being approached, or the blind spot when backing out of a parking space.
The cameras must have the ability to view a large area, so most of the cameras will have a wide-angle lens. The cameras on the sides of the vehicle must have the ability to see the whole side of the vehicle, from the front bumper to the rear bumper. The cameras on the front and rear need to be able to see far to the left and right of the vehicle. Many OEMs offer a disclaimer, warning that there may be blind spots in the camera viewing area. Some of these blind spots are by design and cannot be adjusted.
After all of the cameras have captured the image, the image is sent to an image or video processing module. This is where the images from each camera is pieced together to create one image. The image is then sent to the screen which will display the 360° camera view. Depending on the complexity of the 360° camera view system, other systems may also provide input. The 360° system can tie-in with park assist sensors or other collision avoidance systems, such as rear cross traffic. Some systems are able to detect a moving object in the 360° view, such as a ball rolling or a shopping cart moving towards the vehicle.
Adaptive cruise control system
Adaptive cruise control systems primarily use cameras and sensors to regulate distance to the vehicle ahead. There are many variations in what is used to detect the distance. Some vehicles use an exposed radar in the front bumper, whereas some use a radar that is hidden behind the front bumper. There are even OEMs, such as Volkswagen or Cadillac, that utilize more than one radar behind the front bumper.
Some systems utilize a forward-facing camera, near the review mirror, to help detect vehicle distance. There is at least one OEM that utilizes dual cameras near the rearview mirror to control the adaptive cruise control system.
Radar sensors works by sending radio waves that are reflected off of objects. The time it takes for the radio wave to return indicate how far away the object is, how big the object is, and what direction the object is traveling.
Normally, the radar sensor has its own built-in module. This module makes all the calculations to send and receive signals. Forward facing cameras may also have a module built in. These sensors and cameras detect if there is another vehicle present and the distance to that vehicle. The data from these modules is then sent to other modules in the vehicle, such as the powertrain control module to slow the vehicle if the vehicle ahead is decelerating. There will generally be many modules that use data from the sensor and/or camera. In order for the system to control the vehicle’s speed, information from sensors, such as wheel speed, steering angle, and engine torque, can all contribute to the ACC system. If one of these parts is not functioning properly, it can cause the whole system to fail.
Adaptive lighting system
An adaptive lighting system can have one or more functions depending on the vehicle features. The headlamps can turn to better illuminate around corners based on steering angle. The headlamps may be self-leveling. They may also automatically toggle between high and low beam based on the detection of other vehicles ahead. The system often utilizes an in-vehicle camera. This camera is typically located near the rearview mirror. The camera is used to detect oncoming traffic and vehicles in front of the driver, and adjusts the headlamps accordingly.
The adaptive lighting system is a safety system designed to help you see more clearly at night without affecting other drivers. The system may also help the driver to see more of the corner when turning. This results in the driver being able to more easily see pedestrians, animals, or stopped vehicles along their path of travel.
Blind-spot detection system
The blind-spot detection system uses the radar sensors in the rear of the vehicle. These sensors are normally behind the rear bumper on each side. However, there are some instances where the sensor is in a different location, such as in the tail light or in the quarter panel behind the bumper cover. On a select few vehicles, ultrasonic parking sensors play double duty as blind spot sensors.
Radar sensors work by sending radio waves that are reflected off of objects. The time it takes for the radio wave to return indicate how far away the object is, how big the object is, and what direction the object is traveling.
There is normally an indicator on the side rear view mirrors that will light when there is an object in the blind spot. The indicator light can also be located on the door trim or on the A-pillar trim.
Generally, the radar sensors are set up as a master module and slave module. The slave module communicates to the master module, which communicates to other systems. If the slave module detects an object, the slave module will tell the master module that it sees an object. The master module, generally, will then talk to the door module to turn on the blind spot warning light.
I-CAR offers a variety of free resources through its ADAS Library, from news and webinars to podcasts and links to the latest courses; see https://info.i-car.com/adas
Next, we’ll take a deeper dive into these ADAS systems: Collision Warning and Braking System, Front/Rear Cross Traffic Systems, Night Vision and Park Assist.
