Microsys Introduces Next Generation Automotive Safety Component Test System Based on LabVIEW

Author(s):
Brian Biesheuvel - Microsys Technologies, Inc.

Industry:
Automotive

Products:
Compact FieldPoint, LabVIEW, FieldPoint,

The Challenge:
Performing common automotive safety tests with integrated high-speed video capture and data acquisition control and analysis capabilities.

The Solution:
Developing a PC-based sytem using DAQ and FieldPoint hardware controlled by LabVIEW.

Introduction
With increasing public concern over automotive occupant safety and new legislative requirements, automotive manufacturers are under considerable pressure to develop new safety systems and components. As they rapidly integrate these measures, manufacturers need new test systems to aid engineers in product research and development. Once products are introduced into production, lot accep-tance testing (LAT) verifies maintenance of high product quality levels and standards. To meet this challenge, Microsys introduced its next-generation Automotive Safety Component Test System (ASCTS), based on industry-proven LabVIEW software and data acquisition hardware from National Instruments.

The ASCTS performs air bag deployment tests (with multiple squibs), air bag burst tests, seat belt pretensioner tests, head impact tests, and sled tests. The system provides powerful analysis tools through integrated high-speed video and sensor data display coupled with calculation functions.

Design Considerations
To ensure that the ASCTS met current and possible future test requirements, we took a modular software approach. We developed a smart core operating program that calls hardware driver modules to perform a specific function. New hardware driver modules can be developed easily and added to the core operating program to meet changing test requirements. The system can operate any high-speed digital camera system, for example, by loading the appropriate camera driver. Each test system type and application-specific requirement dictates the driver modules that accompany the core operating program, tailoring each Microsys ASCTS to specific customer requirements.

Each ASCTS installation has its own unique hardware requirements - variable quantities and types of safety interlocks, test chamber controls, camera systems, and sensor channels that require interfacing. Because it is important in any test scenario that test hardware can be operated continuously and produce repeatable, reliable results, we chose National Instruments DAQ and FieldPoint hardware as the system foundation.
One of our key design objectives was to minimize the time between order and delivery while keeping system costs within customer budgets. The powerful graphical programming of LabVIEW and versatile hardware components from National Instruments provided the required flexibility and minimized expensive engineering time.

System Hardware
The system is based on a 400 MHz Pentium II PC, running Windows NT. Installed in the PC are a PCI-MIO-16E-4 for high-speed data acquisition functions, such as triggering the two Kodak Ektapro HS4540 high-speed video cameras and supplying the analog outputs to the power supplies that drive the air-bag ignition squibs; and two PCI-GPIB boards for retrieving the video images from the cameras. Five components of the National Instruments FieldPoint distributed I/O system, which were serially coupled to the PC, were used for sensing test chamber temperatures and for discrete functions such as sensing door closures and controlling door locks, lights, alarm buzzers, ventilators, and air-bag ignition.

System Operation
We designed the ASCTS to control and monitor all of the events in a specified test sequence. During installation, we initially configure the software using the System Configuration screen, with which we can enter customer specifics such as sensor data and calibration information.

The Test Design/Sequence screen provides the flexibility to execute a unique test or to repeat a previous test. Users can design test parameters, such as squib pulse amplitude, duration, and delay (for multiple squib modules); selected lights and cameras; transducers monitored; temperature monitoring duration; event timers; and the prefiring and postfiring sequence of events. With this flexibility, customers can develop new tests for a specific application quickly and efficiently with no source code modifications.

During test execution, the Test Design/Sequence screen displays system status, event execution, and sequence timers so operators can monitor a test in progress. In a typical test, safety interlocks such as door locks, door closure sensors, warning lights, buzzers, and emergency stops are energized and monitored before a test can proceed. Next, the system initializes high-speed video image and data acquisition equipment in preparation for a trigger to commence recording and storing test data. In some tests, peripheral equipment needs to be operated and monitored prior to firing.

For example, in a typical engineering air bag deployment test, where air bags are soaked at preset temperatures, the software activates the raising of the chamber seconds before the deployment to facilitate the cameras and lights placed outside the chamber. After test execution, the ASCTS controls the postfiring stand-down procedure. In this procedure, a countdown sequence timer deactivates all previously activated system components and releases safety interlocks once it is safe for operators to enter the test chamber. During the stand-down procedure, the system downloads video images from digital cameras.

One of the unique features of the Microsys ASCTS is its integrated high-speed video image and data control and analysis capability. The ability to control high-speed video imaging and data acquisition equipment from a single computer simplifies test configuration design and execution, reducing operator error and improving efficiency in the test facility.

For analysis, integrated video and acquired data provide engineers with powerful capabilities by enabling easy correlation between video and sensor data. Multiple video and DAQ test results can be displayed at the same time, so engineers can evaluate design changes. Trace calculation functions and SAE J211 digital filters provide further analysis capabilities. As an optional feature, we provide portable analysis software for remote test data analysis, so the ASCTS can continue testing, further increasing system efficiency.

Conclusion
The ASCTS performs common automotive safety tests through its modular hardware and software design. Each test system is tailored to meet customer requirements for chamber safety interlock control, monitoring, high-speed video capture, and sensor data acquisition. Integrated high-speed video and DAQ coupled with trace math functions provide customers with advanced test analysis capabilities.
With the Microsys ASCTS, customers gain a powerful product development and LAT test system engineered to meet current and future safety requirements.

For more information, contact:

Brian Biesheuvel or Corey Miller

Microsys Technologies Inc.

3100 Steeles Ave. West

Concord, ON L4K 3R1

Tel: 905-761-5250

Fax: 905-761-5244

E-mail: microsys@micro-sys.com

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