Faster flexible testing, higher throughput
Case study: Harman accelerates infotainment system testing and throughput, including increased automation and throughput. Additionally, the stations can easily be adapted to handle evolving products and provide Harman with a competitive advantage.
Harman collaborated with a global test-engineering company to engineer new, more efficient automated functional test (AFT) and end-of-line (EOL) test stations for a new line of infotainment receivers.
Since Harman launched its first car radio in 1948, the user experience in automobiles has evolved enormously. Back then, tuning into an AM station and adjusting the volume were all you could do. In Harman’s current infotainment systems, AM radio is just a small portion of the user experience on offer. At their fingertips, passengers have the latest GPS technology, touch screens, integrated cellphone, iPod, Bluetooth, Wi-Fi, USB capabilities, rear-seat video screens, and radio and music offerings. An additional evolution over the past few years includes enhanced security features and associated “hands-free” functionality, such as provided by Bluetooth and voice recognition.
As more technology is integrated into our automobiles, user expectations are high. Everything must work as expected and work in harmony, with the highest quality. Consequently, infotainment system testing has become increasingly complex. Not only must each feature and technology—such as electrical, RF, and audio/video—be tested and measured individually, but the core system functionality also needs to be rigorously tested to ensure smooth overall operation. Such complex and comprehensive test requirements have obviously led to greatly expanded test infrastructure and lengthier test cycles.
Implementation of next generation testing
Faced with the challenge of quickly and thoroughly testing the latest feature-filled consumer products, many original equipment manufacturers (OEMs) have sought innovative approaches to satisfy technical and business requirements. Harman and the test-engineering company Averna identified the following priorities for the new test systems:
• Flexibility: Optimize production throughput during high-volume periods
• Scalability: Test different infotainment products with minimal changes
• Cost savings: Lower long-term capital expenditures and reduce obsolescence.
Flexible test station design
In a traditional test paradigm, every element of a test system—from test instruments and fixtures to test software—is designed and dedicated for testing just one product. When sales for that product drop off or when the product’s features change dramatically, the test system often has to be significantly overhauled or rendered obsolete.
Through its collaborations with multiple OEMs in numerous industries, the test engineering company has identified ways to extend the purpose and life of test equipment far beyond a “one product” design. The Harman project began by proposing flexible test stations (Figure 1) (sometimes called “generic” or “common” test stations) that would enable Harman to test a range of infotainment systems it produces for different clients, while also allowing the stations to be upgraded at minimal cost to handle new or evolving products. The test station design is based on the following requirements:
• Standard racks with 20% free space for expansion
• Specialized, modular instruments such as PXI
• An industry-standard test executive
• Parallel testing
• Intelligent, swappable fixturing
To start, a 3U PXI form factor was chosen, allowing the system to accommodate multiple PXI instruments for audio generation/analysis, CAN communication, digital I/O, RF switching, and more. For the RF testing, a receiver tester was used that has signal-generation toolkits covering multiple protocols like AM/FM, RDS, DAB, IBOC, Sirius/XM, and GPS. Additional RF generators were also integrated for Wi-Fi and Bluetooth testing.
To maximize productivity, the test stations include “product intelligent” fixturing (Figure 2). The station can accommodate up to four such fixtures, allowing multiple units to be tested at the same time. The fixtures integrate all product-specific elements—such as audio loads, antenna loads, relays and signal distribution—that may only be needed for one product or even one iteration of the product. The test engineering company incorporated specific switching for the unit under test (UUT) in the fixtures to avoid having to over-specify switching subsystems in the stations. In effect, the swappable product-specific fixtures, which are considerably less expensive than instruments, ensure that Harman’s test stations have the widest possible application.
Since a high priority for the test systems was maximizing throughput and instrument usage, an asynchronous parallel architecture was used on the test stations to get more performance from the instruments. For example, rather than using the instruments to test one UUT at a time, multi-core processing and advanced switching combine to share instruments across multiple UUTs, allowing the four UUTs to be tested simultaneously without significantly impacting the testing time of individual units.
To drive this modular-instrument, custom-fixture architecture, Harman and Averna selected and implemented National Instruments’ TestStand test executive, which helps with multi-threading and multi-core processing. For example, the test sequencing was architected so that while Test 2 is underway on UUT1, Test 1 is starting on UUT2, allowing all test instruments to be engaged simultaneously, maximizing usage.
Benefits: swappable fixturing, automation
The newly designed test stations offer many benefits. The stations’ flexible architecture, state-of-the-art instruments, robust switching systems, standard test executives, and swappable fixturing truly allow Harman to cover all its current test needs for different products, including increased automation and throughput. Additionally, these stations can easily be adapted to handle evolving products and provide Harman with a competitive advantage.
- Alex Boyer is team leader – system architecture, Averna Technologies, and Ehab Beshay is senior manager test engineering for Harman International. Edited by Mark T. Hoske, content manager, CFE Media, Control Engineering and Plant Engineering, firstname.lastname@example.org.
Averna provides more information on the Averna RF Studio product for NI's Software Defined Radio Platform. Averna announced RF Studio July 31 and showed it at NIWeek 2013.