Increase in Automotive Electronics Drives Need for Sophisticated Test Equipment

As the auto industry gathers this week for the Society of Automotive Engineers conference in Detroit, the large number of electronics companies exhibiting there is a sign of the times. In less than 15 years, automobiles have been radically transformed from purely mechanical machines into sophisticated, hybrid mechanical-plus-electrical machines. So significant has the transformation been that NASA's space shuttle has less processing performance than some of today's high-end vehicles have in their engine controllers alone!

Driven mainly by the energy crisis and resultant tightening of government pollution standards, in 1974 a group of automotive engineering pioneers identified 55 technologies as probable automobile electronic applications. By 1996, more than 90 percent of those applications, and some they couldn't have possibly imagined, had become reality. In addition to the core improvements brought by advances such as electronic fuel injection and air bags, safety and convenience features such as heads-up displays, voice synthesis/voice recognition, four-wheel steering, ABS/traction control, electro-chromatic glass, and heated windshields were invented. It is predicted that within one or two decades, all automobile functions will be 100 percent under the control of numerous microprocessor/controller systems.

All these electronic system advancements have been good for the consumer, but have been even better for companies like Keithley Instruments, Inc., (KEI:NYSE) a Cleveland, Ohio-based manufacturer of precision electronic test equipment. The parts may have changed, but consumer expectations for a safe and reliable vehicle have not, creating a new challenge and opportunity for manufacturers of test equipment. The more sophisticated the automotive system, the more sophisticated the test procedure and equipment. It's a relationship that will only continue to grow more co-dependent as an automobile's core functional systems evolve electrically.

Today, well over $1,000 of an average vehicle's manufacturing cost is comprised of electronic devices and systems, and that figure is expected to increase rapidly. The need for fast and accurate test equipment is critical to accommodate the high volume automotive electronics production assembly environment. Safety, entertainment, and power transmission system applications are just a few of an automobile's functions that have transitioned from mechanical to electronic controls, thus requiring many new testing strategies.

Active Safety Systems

This is obviously important for automobile safety features such as the airbag system. Manufacturers must perform numerous tests on nearly every aspect of an airbag system to ensure proper performance. At each test station along the assembly line, several measurements at high accuracy and speed are required to maintain production at a brisk pace. These were the challenges facing Autoliv Automotive Safety Products, Inc. when it began designing a new test system for development and production of airbags supplied to the worldwide automotive industry.

Autoliv, which produces more than 120,000 airbag modules per day, needed a system for its electrical test station that would be capable of performing three critical tests, each requiring different voltages, currents and test points. Not only did the system have to maintain high accuracy and dependability, it also had to meet Autoliv's rigorous 24/7 production schedule.

To ensure that the airbag fires safely and accurately when needed, Autoliv performs three electrical quality tests on the inflator initiator circuits of each module. At the electrical test station, the first test measures the resistance of the initiator. A second test checks a shorting clip to verify that initiator pins are shorted together prior to airbag installation. A third test is a high voltage resistance measurement to make sure there is no electrical path between the initiator and the module case, which might cause a no-fire situation.

During testing, the system monitors I/O and acts as an inspection device by using sensors to detect such things as bracket placement, the presence of labels and proper color-coded connectors. The old Autoliv test system used PLCs attached to the company’s data collection LAN, but because of frequent product modifications and new models, a large amount of time was required to reconfigure test instruments and modify software for the PLCs.

To increase throughput and minimize future modification costs, Autoliv designed new electrical test stations for PC-controlled testing with GPIB instruments and data acquisition devices from Keithley Instruments. Autoliv selected Keithley's Model 237 Source-Measure Unit and Model 7001 Switch System to allow easy programming changes as products and testing requirements change. According to Julie McCulley, an automation controls engineer at Autoliv, the test system now provides the accuracy and speed needed in a production environment.

As Autoliv and other airbag system makers evolve toward smarter crash and occupant sensing systems, electrical testing of all transducers, controllers and actuators will increase in volume and criticality.

Telematics and Info-Tainment Systems

Based on the marketing success of in-vehicle computing and communications systems such as General Motors' On-Star, all major carmakers are rushing to develop and incorporate the essential hardware, software and service elements of the connected, or smart, vehicle. Typically, these systems are built into or around the radio system by adding cellular transceivers and Global Positioning systems, taking advantage of processing power of the radio, or in some cases, an added PC-like device. These systems enable 2-way voice and vehicle/location data communications with a service provider, yielding safety services such as direction finding and navigation, lockout protection, crash signaling, including automatic 911 dispatch, and theft tracking as well as vehicle self-diagnostics. Such systems require the merging of computing and communications technologies and much more sophisticated electronic testing of DC and RF signals. Being able to obtain both DC and RF precision testing solutions for these systems is key to effective commercialization of these emerging safety-critical systems.

Mechanical Systems

Luk Inc., a manufacturer of clutches and torque converters for the automotive and trucking industries, had testing requirements that included control of multiple test stands and real-time data acquisition. Clutch materials and designs are evaluated during product research, development, and production, where speed and torque readings are used to calculate friction coefficients. While Luk wanted to control the data acquisition process, the company did not want to dedicate a PC-based system to each test stand. Using plug-in boards with local microprocessors and memory to offload the PC's processor was the solution. The strategy of using a dedicated processor yielded the sampling and response rates needed for real-time applications where events had to be handled within a guaranteed time period.

Using Keithley Instruments' ADwin product line of real-time process control boards and Luk's software, a test system was designed that performed four basic tests on clutch assemblies. The slippage, engagement, breakaway and flush tests each helped determine the functionality of a specific part of the clutch assembly. With this test system, up to 10 processes for fast control, signal processing, and data acquisition could be calculated in parallel. Data transfers between the processor and a PC were executed in the background so there was no effect on real-time operations. In this particular application, data acquisition and control processes ran four test stands simultaneously, thus satisfying Luk's requirements for real-time measurement and control.


Following the explosive consumer electronics applications trends during the 1980s and the Internet- and mobile phone-driven communications growth of the 1990s, the next two decades promise to be equally, if not more, significant in the use of electronics to dramatically improve vehicle safety, performance and efficiency. Manufacturers of a broad range of commercial and communications electronic test equipment can look forward to enjoying the ride in the smart and connected vehicles of the future.