Advanced Driver-Assistance Systems require better education, understanding

Oct. 3, 2018
When asked to find the centerline of the vehicle it is critical to understand why; sensors are attached to the vehicle, so it should be obvious that they need to know which way the vehicle is pointed or traveling.

Technology is being deployed rapidly in today’s vehicles; capabilities such as sonar and radar have been prevalent for years, but with the introduction of forward-facing cameras and the fusion of sensor technologies, the chance you’ll see one in your service bay is high. Many of you have experienced the sonar warning features that prevent you from bumping into the car behind you, or the vehicle next to you when parking. Located behind the bumper covers of millions of vehicles, these systems have become common place. Another common technology is the adaptive cruise control systems that use forward-facing short and long-range radar to keep a safe distance between you and the vehicles in front of you.

Then came the introduction of technologies like lane departure warning, autonomous park assist, and autonomous emergency braking. These technologies are being adopted at a rapid pace led, by autonomous emergency braking, or AEB, which today numbers more than 18 million worldwide. It’s interesting to note that the National Highway Transportation Safety Administration (NHTSA) was poised to mandate AEB, but was approached by the OEMs with a proposal of voluntary commitment by 20 manufacturers to implement AEB on all vehicles sold in North America by September of 2022. What does this mean for you? It means in order to be service ready for your customers, you must be able to service these systems properly before they arrive at your business.

This opportunity has presented itself to us many times before in the form of ABS, Stability Control, TPMS, etc. If you recall, these systems tended to be fairly robust and didn’t cause too much stress for many years, giving us a chance to learn our way through them. But in the case of Advanced Driver-Assistance Systems (ADAS), we have a question of when to service or calibrate that must be answered. There is no doubt we as an industry can handle this technology just like we have with others in the past, however, this time we need to be better educated going in due to the passive nature of these systems. By passive I am referring to the fact that ADAS systems, while constantly monitoring and adjusting, are not reacting in a visible or noticeable way until there is a need to do so. This means if we have not adjusted or calibrated the technologies properly, there is a chance these systems will overreact or under-react to the situation at hand. Either of these conditions could result in an accident or harm to the motorist. While liability is in play here, the fact is the OEMs have invested tremendous capital to validate the technologies and to create robust failure modes that keep motorist safe. However, this means we need to follow the processes they have designed when servicing and calibrating ADAS systems.

In order to understand how to calibrate ADAS systems, it is best to start with the basics. In most all cases the first step in a calibration is to locate the centerline of the vehicle; how this is accomplished differs by OEM. Some use fixtures attached to alignment machines, while others use a simple plumb bob and tape measure coupled with some simple trigonometry. Remember when the teacher told you to pay attention during math class? This is why.

Now is a good time to make a statement about following OE process. I agree that it is important to follow the processes spelled out by the OEM. During many calibration or service procedures, the OEM first describes how to find the centerline of the vehicle followed by the placement of a target used to calibrate the technology; i.e. camera or radar, followed by the initiation of the calibration via the use of a scan tool. Essentially, three critical steps that must be accomplished with accuracy, however, let’s take a look at what the OEM is asking us to do.

When asked to find the centerline of the vehicle it is critical to understand why; sensors are attached to the vehicle, so it should be obvious that they need to know which way the vehicle is pointed or traveling. Most calibrations are designed to use targets placed in a precise spot relative to the center line of the vehicle. But there are a couple caveats to consider. First is how does the Steering Angle Sensor (SAS) relate to the centerline? Answer; it is critical, which means if you adjust the SAS during an alignment, you may need to calibrate ADAS sensors as well. Second, the critical part of this step is to find the centerline of the vehicle. If you look at how Honda or Toyota define this process, you can quickly see that it is simple trigonometry. Toyota has you hold the string of a plumb bob on the center of the Toyota emblem on the hood or trunk of their vehicle to find the center of the front or rear, then snapping a chalk line between the two establishes the centerline. This is followed by measuring a prescribed distance from the front plumb bob point to find two center points where you use a string of a prescribed distance and a marker to scribe an arc. Where the two arcs intersect on either side of the centerline is the point you will place a target. Pretty simple, right? However, there are several aftermarket target solutions that use lasers, tape measures and fixtures to do the same but in a similar method for multiple makes of vehicles. Is one better than the other? The answer is no as long as the result is placing the target in the proper position relative to the centerline of the vehicle.

Next you need targets; the OEM prescribes a specific target of a particular size, shape and pattern to be placed is the spot we described above. The challenge is to find these targets; if you try to buy them from the OEM, you’ll find there is a challenge in availability. Many manufacturers simply don’t have them in stock. Or, you’ll discover the OEM provides then in their technical information system with printing instructions. This makes it easy to access but comes with a word of warning; READ THE PRINTING INSTRUCTIONS!! You can search YouTube for examples of someone not reading the instructions, placing the printed target in the wrong location and still getting the controller to accept the calibration. There are several aftermarket target solutions on the market that are exact replicas of the OEM target. They are robust and come with the fixtures needed to place them in the proper position. Some will argue that you must use an OE target to be successful. The fact of the matter is the vehicle controller doesn’t care as long is it is a target that is the same size, shape and pattern and it’s placed in the proper position.

Finally, you will need to initiate the calibration. This is often accomplished by reading information displayed on the dash. Factory service information or the equivalent is a good source of this technique. However most require or can use a scan tool. It is critical to understand that the scan tool does not do the calibration of the sensor or technology; it is simply the messenger of the request you are sending to the onboard controller. This means that an aftermarket scan tool that implemented the requests it acquired from the OEM via either ETI or the OEM directly will work successfully. Of course, there are scan tools that won’t implement properly, and the result will be no calibration.

At the end of the day, there are some unknowns regarding aftermarket tools and targets when calibrating ADAS technologies. The aftermarket needs to do a better job of providing information that gives shop owners and technicians confidence in the products, and the OEMs need to consider those situations where aftermarket tools, if implemented properly, will result in an accurate calibration by way of adding the statement “or equivalent” to their position statements. It is process that is king, and as long as you find the centerline of the vehicle, place the target that is the right size, shape, and pattern in the proper position and initiate the calibration properly, the system will operate as designed. After all we currently install aftermarket brake pads and ABS accumulators, and Steering Angle Sensors, and program immobilizer controllers and engine controllers using aftermarket scan tools. If we keep the fundamentals of the technologies in focus, we’ll all be successful.

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