January 27, 2017 4:06 PM, EST
Detecting a Problem
Active Safety Systems’ Radar Sensors Causing Some Concern, Maintenance Experts Say
McKenzie Tank Lines

This story appears in the Jan. 23 print edition of Equipment & Maintenance Update, a supplement to Transport Topics.

Fleets that have adopted the latest in active safety technologies, such as adaptive cruise and electronic stability control and, most recently, collision mitigation, report that there is little additional maintenance associated with these complex electronic systems on trucks. But one element of these systems that does cause some concern among maintenance managers is the position and operation of the radar sensor, a component of adaptive cruise control and an important part of the latest generation systems that have automatic braking.

One new system was showcased in October by Volvo Trucks North America at the closed-track Michelin Proving Grounds in Laurens, South Carolina. Called Volvo Active Driver Assist, the system features a bumper-mounted radar sensor and an added video feed from a windshield-mounted camera that “recognizes” stationary vehicles and performs active braking to avoid an accident.

Invited to contribute to the Volvo Active Driver Assist program was Jim Kennedy, vice president of maintenance for Tallahassee, Florida-based McKenzie Tank Lines, which says it’s a pioneer in the adoption of safety systems for its tank fleet. After his presentation on safety programs at McKenzie — from early ABS adoption through air disc brakes to the latest stability and automatic braking — Kennedy said adoption of the systems had improved the fleet’s safety performance significantly at little additional cost for maintenance.

The only issue had been with the alignment of the radar sensor, Kennedy said.

This was echoed by Kirk Altrichter, vice president of fleet services for Kenan Advantage Group, based in Canton, Ohio.

“The radar unit has been the piece that required the most work over time — mostly around alignment issues,” Altrichter said. “The later models are self-aligning,” he said of the updated radar sensors that recognize misalignment due to small accidents and compensate automatically.

“But they are not proof against physical damage,” said Altrichter. “Deer strikes tend to take them out. They don’t hold up well to front-end animal damage at all. It would be nice if they were up a little higher so they weren’t in a danger zone.”

Also at the Volvo event was Fred Andersky, director of customer solutions and marketing at Bendix Commercial Vehicle Systems, who drove one of the demonstration trucks at the test track. Volvo’s new safety technology is based on the Bendix Wingman Fusion active safety system with the display integrated into the Volvo dashboard.

Andersky said the electronic sensors used by driver-assistance systems “are pretty durable and robust in terms of performance.”

However, issues can arise, Andersky said. “If the radar or the camera gets blocked, the radar can sometimes become obscured through muddy or blizzard conditions, especially when it packs up with snow,” he said. If a driver receives a radar false alert, “we recommend he get out at his next stop and take a look at the radar. And if it’s blocked, wipe it off.”

Alignment of the radar used to be a problem, Andersky agreed. “It’s not as much of a concern now,” he said, noting the radar “has a lot more forgiveness built into it now in terms of alignment.”

Another North American supplier of collision avoidance systems is Meritor Wabco with the OnGuard system.

“The electronics are designed to conduct self-tests when the unit is keyed on,” said Mark Melletat, Meritor Wabco’s director of trailer support and field operations. The original radar units were not self-aligning, he said, but the new ones do have a self-alignment function.

“During operation, they make minor adjustments automatically,” Melletat said.

“If a bracket is bent severely, they won’t be able to adjust it to that level,” he said. “But certainly they do minor adjustments. So you don’t need special costly alignment equipment. You just set the system to do a self-alignment and it does it.”

To ensure the system is functioning normally, OnGuard self-tests when the truck is keyed on.

“It performs the tests, and the warning light comes on, then the light is extinguished if there are no issues,” said Melletat. “There are safety controls inside the units with micro components. They send small pulses continuously to report whether the systems are functioning properly and look at the signatures to find tests that deviate from the norm.”

Any system issues can be diagnosed with the tools and service literature Meritor Wabco makes available, said Melletat.

At Daimler Trucks North America, a recent and unique addition to the test set is the logging of faults from these self-tests. The fault codes monitored by the Detroit Connect Virtual Technician integrated remote diagnostic system now include those generated by the Detroit Assurance suite of safety systems, said director of telematics Matt Pfaffenbach. Instead of simply lighting the dashboard warning, the program presents a logged fault for diagnosis.

Available on Freightliner Cascadia and Cascadia Evolution models with Detroit engines, Detroit Assurance is integrated with the truck’s engine, transmission as well as the braking system and dashboard.

Virtual Technician captures Detroit Assurance fault codes, then uses cellular communications to notify fleets of the fault details and provide an initial diagnosis within minutes. The new Detroit Assurance fault codes will primarily be for system malfunctions or when Active Brake Assist has been disabled by the driver.

“We are not just expanding the number of faults monitored by Virtual Technician, we are further integrating our connectivity offerings with the rest of the Detroit product lineup,” Pfaffenbach said.

For Brent Hilton, director of maintenance for Maverick Transportation in Little Rock, Arkansas, having a logged fault code is beneficial. “These systems are electronic, and any time you have anything electrical with wiring, you’re going to have issues,” said Hilton. “If something stops working and it’s diagnosed to be faulty, by the time we get unstrapped and unloomed and sent back for warranty, the manufacturers tell us the thing is OK,” he said. “It’s frustrating.”

But a fault code and a diagnostic procedure to back up a claim for warranty could turn the tables in his favor.

Like Kennedy and Altrichter, Hilton has had problems with the radar sensor. “They’re prone to being hit or the mountings get cracked or the screws loosen.”

But he says the rest of the different safety components, especially those located in the cab, are mostly trouble-free. “The technology that’s in the cab, like lane departure and cameras, are protected from the weather. We don’t have to replace anything.”

Meanwhile, Andersky summed up the preventive aspects of these active safety system technologies to what he calls the “three Ps.”

“The first P is the driver doing his pre-trip inspection, making sure the radar is clean, making sure the windshield is clean, so stuff can be seen,” he said.

And because the operation of stability control and automatic braking or collision mitigation relies heavily on the braking system, the second P is for brake PMs, Andersky said. “To keep the braking system in good shape, the fleet should do preventive maintenance.” The braking system is more than just the wheel end, it’s the charging system, which includes the compressor and the air dryer as well, he said.

Finally, if a problem, the third P, does come up, make that repair “as quickly as possible,” he said.

There are some safety system component requirements that fleets should recognize if service is needed.

“The only other area I would touch on is the individual technologies that may require some special consideration, for example, the stability system,” said Andersky. “If a fleet does front end alignments or front end work on the vehicle, they should make sure the steer angle center is recalibrated,” noting that’s fairly easy to do with diagnostic software from suppliers such as Bendix. ³