Freightliner LLC, a leading heavy-duty truck manufacturer in North America, selected National Instruments LabVIEW software and NI PXI-based hardware to replace a VME-based proprietary solution for verifying electrical assembly on its new line of heavy-duty trucks.
Using NI tools, Freightliner engineers integrated electrical test, machine vision and physical measurements into a system that not only ensures high-quality vehicles but also instructs operators on the correct assembly process.
“We set out to design a high-performance test system that would give us the flexibility of a completely off-the-shelf solution and provide both the open architecture and power for expanding the application in the future,” said John Rokus, manufacturing manager of Test and Technology at Freightliner LLC.
“This system delivers on both requirements and the successful development is reflective of the valuable relationships Freightliner enjoys with both external and internal resources.”
Freightliner chose Wineman Technology Inc., a specialty machine designer and a leading National Instruments Alliance Partner, to create the test systems to meet Freightliner’s requirements. Wineman Technology has a strong history of meeting customer needs using PXI-based systems.
The platform’s ability to deliver on flexibility and performance, as well as be more cost-effective than the previous system, made it a natural choice for this application. Along with electrical and physical measurements, the new solution includes a machine vision system for inspecting fuse box assembly. This system features industry-standard cameras that were built into a custom fixture and coupled with software written in LabVIEW.
The software communicates with the plant information system to acquire a build order specific to each truck. The software then graphically prompts the operator to place the fuses and relays in their proper positions in the fuse box or switch activation module (SAM).
Once finished, the operator prompts the system to take a digital picture of the populated assembly and compares it to the computer-generated image of the build order to produce a pass or fail rating. In the event of a failure, the software locks the part in place and notifies the operator which fuse or relay has been placed incorrectly and graphically identifies the part and its correct placement.
“Using machine vision to verify the assembly of the fuse box goes beyond the industry standard of validating serial fuse continuity,” said Darryn La Zar, vice president of Sales and Marketing at Wineman Technology. “For instance, this solution can detect if a 30 A fuse is in a 5 A slot, which was not possible before.”
Once the tests are completed, a Cumulative Offline Report provides an interactive resource for technicians to view results of all previous test systems for any given truck. A to do list is generated in the event that any test failures could not be repaired in station.
In addition, if there are any special truck options that require additional setup or validation, this system compiles those requirements so that a technician can be sure to address them prior to releasing the vehicle.
The new test systems Wineman Technology is building for the plant include all new cockpit and cab testers capable of reading multiple signal types across 512 discrete wires that users can connect directly to the assemblies.
By integrating LabVIEW software and PXI hardware with proprietary PROVEtech software from Mercedes-Benz Technology, the three-way partnership between Freightliner, Wineman and Mercedes-Benz produced a system capable of guiding the operator through each step of the process required to validate all electrical signals that could have been assembled incorrectly or damaged during the assembly process.
PCI eXtensions for Instrumentation (PXI) is an open specification governed by the PXI Systems Alliance that defines a rugged, CompactPCI-based platform optimised for test, measurement and control.
Founded in 1997, the PXI specification is supported by more than 70 member companies, and more than 1,200 products are available. PXI products are compatible with the CompactPCI and CompactPCI Express industrial computer standards and offer additional features such as environmental specifications, standardised software and built-in timing and synchronisation.