ADAS Calibrations: Speed and Accuracy Go Hand-in-Hand
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ADAS Calibrations: Speed and Accuracy Go Hand-in-Hand

Innovations in calibration systems have made setup and vehicle-to-target positioning — the most time-consuming segment of ADAS calibration — faster.

This September, 20 automakers will hopefully follow through on their commitment to have 95% of their vehicles include forward collision warning (FCW) and city-speed automatic emergency braking (AEB). Audi, BMW, Ford/Lincoln, Honda/Acura, Hyundai/Genesis, Mazda, Mercedes-Benz, Subaru, Tesla, Toyota/Lexus, Volkswagen and Volvo have already met that goal. Many of these systems will not only include radar units but also front-facing cameras to ensure that their systems will work as intended. This commitment adds to the estimated 60 million vehicles on the road today with some form of advanced driver-assistance systems (ADAS).

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Fast and Efficient

This exponential growth in the number of vehicles with ADAS should act as a catalyst for shops that perform calibrations to develop a process that enables them to do them as efficiently and accurately as possible. Innovations in calibration systems have made the most time-consuming segment of ADAS calibration — setup and vehicle-to-target positioning — faster. They have also provided technicians with a calibration process that is both efficient and precise.

The setup is the most time-consuming process of static calibrations. Depending on the vehicle, a manual frame-to-vehicle pre-calibration can take upwards of 40 minutes. The setup is by far the most time-consuming part of a typical ADAS component calibration. Once the vehicle and targets/patterns/calibration components are positioned, the ADAS software is initiated on the scan tool and, within minutes, a successful calibration message displays — and you’re off for a test drive to ensure accuracy, then handing the keys back to the customer.

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Calibration Requirements

The typical static calibration requirements insist that the vehicle be on a flat, level surface. And, in the case of a camera calibration, it should be done in a bright, controlled-lighting environment. The area behind the calibration targets should be clear and clutter-free. In the case of radar calibration, no metal objects should be within the calibration space.

The “whys” of these requirements seem straightforward: We’re calibrating a camera with a target that has a white background and a black image on it. We want to create the most ideal setting for the cameras to “see” the targets. Dim, uneven lighting or glare will hinder the camera’s ability to recognize the targets.

Additionally, there should no clutter, signs or photos behind the target as they might “confuse” the camera. If we’re calibrating radar devices — components meant to detect metal objects — we don’t want to have other metal objects in the vicinity of the vehicle’s radar unit and the positioned calibrator. In a shop environment, this might mean moving metal garbage pails, tire machines or toolboxes to another space in the shop.

And how important is it for the calibration to be performed on a flat, level surface? Really important, as one aspect of the positioning of the target to the vehicle is dependent on the vehicle’s rear drive line. An uneven floor might throw off the pitch of the vehicle and may result in an improper calibration. (When an alignment rack is used during calibration, the technician would be prompted to enter the height of the rack from the floor into the calibration software on the scan tool. An adjusted target position height is calculated and displayed.)

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Vehicle Requirements

The next step before a calibration is to ensure that the vehicle itself meets a list of conditions, including that all fluids are at recommended levels, the gas tank is full, the tire pressure on all tires is at the placard-listed PSI and that the vehicle carries no additional load — no groceries, luggage or heavy equipment.

The “why” here is perhaps a little less straightforward, but George Lesniak, head ADAS trainer for Autel, offers the best rationale: that these prescribed conditions seek to emulate the “stance” of the vehicle when it left the factory floor and went on to be calibrated. The original equipment (OE) is in essence saying the camera or radar components were initially calibrated when the vehicle met these conditions, and to ensure these input components perform as designed to inform the operation of the system, these original pre-calibration conditions must be met. Failure to meet these conditions may compromise the calibration and therefore compromise the effectiveness of the safety system overall.

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Additional prescribed conditions include making sure that all lights are off in the vehicle and all doors are closed to ensure the vehicle battery is not drained during the calibration. For the same reason, a battery maintainer should be connected to the vehicle.

Target Positioning

The next step prior to the calibration is to ensure that the target is positioned correctly to the vehicle. Autel’s standard calibration frame system uses lasers, mirrors, rear wheel clamps and a tape measure to position the frame to the vehicle. The technician uses the center laser on the frame to first detect the centerline of the vehicle. Measuring tape is used to ensure that the frame is at the distance to the vehicle specified by the OE. Next, the rear wheel clamps with lasers are used with the frame to ensure that the crossbar (and, subsequently, the OE-specific target when attached) is perpendicular to the rear axle of the vehicle. Next, the clamps and frame are used again to ensure that the angle of the frame is positioned to the driveline of the vehicle.

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Why are all these steps performed? Because it is the thrust angle (the angle generated from the vehicle’s rear axle) that dictates the direction of the vehicle as it ventures down the road. Autel’s frame is positioned to the reference point of the vehicle thrust angle.

New Systems

Calibration system developers have heard technicians’ lamentations and answered with new systems or adaptations for existing ones that not only drastically cut the setup time but also ensure a more precise positioning of the vehicle. No plumb bobs, chalk or measuring tape.

Autel’s IA800 is one such solution. Described as an intelligent ADAS optical positioning system, the IA800 employs six high-resolution cameras and ADAS positioning software to transform Autel’s standard calibration frame into a rapid yet precise frame centering and vehicle distancing unit, enabling technicians to accomplish frame-to-vehicle placement in less than three minutes. Compare that with the mechanical tool’s setup that takes 40 minutes on average.

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Wheel clamps with camera targets are attached to the rear wheels, and a standing target component is placed in the front of the vehicle by the vehicle badge. The tablet, now placed securely on the frame, is paired with the cameras.

The system recognizes the positioning targets and calculates the current angle, distance and offset position of the frame to the vehicle. The technician simply follows the on-screen instructions to move the frame or adjust its angle until the current values match the required values. A green check mark will display for each parameter once the required position values are achieved.

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Pre-check

An important feature of the IA800 is the pre-check function. Proper vehicle alignment is essential to the calibration of all ADAS components. The thrust angle, calculated in reference to the vehicle’s rear axle, determines the vehicle’s direction as it travels down the road. As discussed earlier, this reference enables the correct centering and position of the frame and its targets/patterns when positioning the calibration frame and its patterns/targets to the vehicle. Pre-check uses the IA800’s camera system and targeted wheel clamps attached to all four wheels to determine the vehicle’s current alignment specifications and compare them with the vehicle manufacturer’s allowed tolerances. If within OE-specified tolerances, the technician can proceed to optical positioning of the frame to the vehicle.

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Autel’s just released IA900WA wheel alignment ADAS calibration solution improves the pre-check function of the IA800 by giving the technician a one-system solution to the ADAS calibration process. In fact, the IA900WA is an industry-first by offering four-wheel alignment and ADAS calibration all in one.

The IA900WA features a folding crossbar, and six high-resolution positioning and tracking cameras in frame automatically monitor vehicle height on the shop lift. Also, there is robotic frame movement for efficient use and alignment reading accuracy to 0.02 degrees. Alignment coverage is for U.S., Asian and European vehicles 1996 and newer, and the user is guided through the complete process with illustrated alignment instructions, live readings and required tools. Also, adjustment locations display on an included 24-inch touchscreen display.

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The IA900WA system is offered in various packages, including an all-systems ADAS package that includes targets, patterns and calibration components to calibrate cameras, radar, LIDAR and night-vision units.

Summary

As vehicle manufacturers continue to share their safety systems throughout their entire lines and more and more vehicles with these systems enter shops, it will be essential for technicians to have solutions that provide them with a repeatable, efficient process to calibrate these input devices.

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