One of the most memorable automotive advertising campaigns of the 21st century was GM’s “This is not your father’s Oldsmobile.” While the campaign couldn’t predict the demise of the venerable Oldsmobile brand, it clearly highlighted the accelerating pace of innovation in automotive technology. Car prices in 2018 make classic car prices look like a steal, but today’s modern car packs more value per dollar, thanks to technology-driven conveniences, safety features, and advances in drivetrain technology that, in comparison, make the ’57 Chevy or ’52 Austin look like a dinosaur.
Innovative test techniques in automotive electronics are helping to drive functionality up while keeping costs down. Let’s look at five techniques that help drive the state-of-the-art, without driving up cost:
- Component Level Testing—Miniaturized Test
- Board Level Testing—Fully Automated ICT
- Functional Level Testing—Automotive Test-Under-Load
- Hardware-in-the-Loop Testing
- Artificial Intelligence (AI)
As a comparison, take a 1952 Austin A30 and a 2018 Nissan Leaf—both family cars, but 66 years apart. Besides the obvious addition of comfort features like infotainment and seamless smartphone connectivity, the new generation of 100 percent electric vehicles (EV) offer advanced driver-assistance systems (ADAS) features. These features range from keeping safe distances with the car in front, to pedestrian detection. They even include options for emergency calls, in the event that the driver is incapacitated in a serious accident. Automotive electronics have enabled such features, which are fast becoming standard offerings, even for entry-level vehicles, making the Austin A30 seem like a relic by today’s technology standards. A visual comparison of today’s dashboards and those of our grandfather’s car shows up the plethora of technological advancements (Figure 1).
By 2020, the cost of automotive electronics will make up 35 percent of the total car cost, versus just a mere 1 percent back in the 1950s (Figure 2). The most obvious change is the exponential growth in the number of electronic components driving today’s latest safety and infotainment features. For the carmaker, the primary goals are maintaining affordability without any compromise to safety, especially in the age of autonomous driving.
Test Better with No Compromises
With the rapid development and huge potential of the autonomous driving market, carmakers and automotive equipment manufacturers face the same challenge: achieving zero failure without letting the cost of test hijack quality.
Unlike the consumer electronics market, achieving zero parts-per-million failure may not be the priority for electronics manufacturing suppliers (EMS). For automotive EMS companies, this has risen to the top of their list with stringent regulatory standards and customer expectations.
From the component level of power conversion devices and radar sensor units, to the printed circuit board assemblies (PCBA) and electronics control units (ECUs), right to the miles of cables and the hundreds of connectors, every one of these components and subsystems must be tested and verified (Figure 3).
While the number of tests and the complexity of each test has grown, any test manager would tell you the basic expectations around managing the cost of tests have not changed. Here are some challenges that may make a test manager lose sleep at night:
- How can I reduce my cost of tests by 10 percent from last year’s budget?
- How do I reduce my repairs and manufacturing defective fallout?
- How do I make sure my line achieves Zero Defects?
- How do I guarantee my solution meets all the required regulatory authorities’ standards?
- How do I prevent recalls (at its mildest, at the PCBA level, and in the worst-case scenario—complete recall of a new car fleet)?
There is no simple formula to calculate the cost of tests. Take PCBA testing on a typical surface mount technology (SMT) line for example. The formula could include any of the following parameters:
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PCBA test cost = Automated optical inspection (AOI) + automated x-ray inspection + PCBA electrical test (using manufacturing defect analyzers (MDA), in-circuit test (ICT), or flying probes) + functional test (FT) + test duration + test yield + volume |
Add to that fixtures, operators, and tester costs. You get the picture why pinning down the cost of test is an elusive task.
Reducing Supply Chain Costs
Automotive circuit boards have become increasingly complex. New PCBAs host many powerful processors and handle massive amounts of closely interwoven mechatronic functions. This puts tremendous cost pressure on the average EMS. With margins per PCBA approaching mere cents, EMS veterans are adept at keeping the cost of tests down, while extending test coverage to meet stringent automotive regulatory requirements and Zero Defects goals. Let’s look at the different levels of tests.
1. Component Level Testing—Miniaturized Test
The ability to reduce design and test cycles equates to time and cost savings. These savings start right at the component level.
Take connectors for example. An entry-level car may use more than 100 connectors, while a BMW 7 Series can sport 500 connectors. Connector pin counts have doubled to more than 300 from just a few years ago, with ever-decreasing pitch. To tackle this, engineers are now using miniaturized probing technology to examine today’s high-density PCBAs, spotting quality issues, such as signal integrity for ultra-small IC packaging and GHz signalling.
Another area being optimized in automotive is the design and performance verification of wide bandgap (WBG) devices to gain higher efficiency (extended range) and higher power in smaller, lighter, and lower temperature packages. Designers must contend with a host of test challenges on these new WBG devices, such as in-rush currents, overshoots, ringing, and switching times. These days, state-of-the-art modelling software and power circuit simulation tools, such as curve tracing and double-pulse testers, help engineers to build and verify sophisticated WBG device models, reducing the cost of design and helping to lower final component cost.
2. Board Level Testing—Fully Automated ICT
Demand for fully-automated ICT (Figure 4) has risen in recent years in the automotive sector. Apart from saving on manpower costs and avoiding damage to highly sensitive boards due to electrostatic discharge from human handling, smaller footprint automated inline ICT systems can help the EMS shave seconds off the test time for each board. At the board component level, innovations in boundary scan test help to catch structural defects such as opens and shorts.
3. Functional Level Testing—Automotive Test-Under-Load
Functional testing is an essential checkpoint for any automotive PCBA production line just before the boards, such as an automotive ECU, gets packed and shipped. A typical mechatronic ECU these days has 200 to 450 pins, each of which must be tested. In the past when devices under test (DUT) were simpler, manufacturers could easily manage the testing of these DUTs with general purpose relays. However, many of today’s ECUs for electronic immobilizers, parking brakes, airbags, clutch applications, and body control require high-power switch and load test capabilities.
To save on manpower costs and the complex task of self-integrating their functional test solutions, automotive manufacturers have increasingly turned to ready off-the-shelf, “reusable” functional test solutions. Solutions based on PCI extensions for instrumentation (PXI) allow the flexibility of using the same instrument to test different automotive ECUs.
4. Hardware-in-the-Loop Testing
From the component, right through the board level, the journey to enabling autonomous driving can only be smooth and safe if all parts work cohesively as a sum. This is where hardware-in-the-loop (HIL) tests are playing increasingly vital roles to test and validate components and systems, to make sure, early in the development phase, that they function in the real world.
With powerful software that can emulate comprehensive traffic, driver, pedestrian, and even wildlife and weather scenarios, the HIL test opens a whole new horizon of design and test possibilities—physically or virtually.
Advocates of HIL test list these common benefits:
- Cost effectiveness: HIL simulation often requires significantly less hardware than physical prototyping, thereby reducing the cost of tests.
- Non-destructive nature: HIL simulation often makes it possible to simulate destructive events (e.g., vehicle accidents) without incurring the costly destruction.
- Repeatability: Tests with permutations of random situations that are hard to replicate in real life, such as hailstones under low visibility, can be repeated easily.
5. Artificial Intelligence
Per research firm Markets and Markets, the automotive AI market will be worth $10.6 billion by 2025, from $782.9 million in 2017. Developers are already pushing both hardware and software to new limits in this area. An interesting example is graphics processing unit (GPU) vendor Nvidia. It leapt from enabling realistic gaming using AI algorithms, to leveraging their expertise in AI to teach cars “to see, think, and learn.”
Developers are also exploring how to miniaturize big data into packages, so that onboard deep-learning platforms can “think like a human driver” when, for example, navigation maps are outdated, and the car needs to mitigate new road conditions on the fly.
Keeping in mind the original goals of zero failure, automotive test engineers reap the benefits of innovative technology to make their work easier. These benefits filter to drivers, passengers, and pedestrians; putting autonomous driving within reach of all.
