Heitz Automotive Testing LLC |
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Unique Capabilities of Data Acquisition System
In many test programs there is visual and auditory "data" which can be seen or heard but not measured. The ATI "Real-time Video Data Acquisition System" (US Patent 4,819,896) overcomes this problem by recording all three sources of information - sight, sound, and instruments - simultaneously and in synchronism, on videotape. Display Capabilities - The real-time data display overlaid on the video picture has proved to be particularly useful. For example, in accident scene drivethroughs, in demonstration of avoidance maneuvers, and in standard lane-change tests the video picture can be single-framed, with steering wheel angle, lateral acceleration, and other variables shown in 1/30 second increments against the driver's view of lane boundaries or other obstacles. Video G-G Diagram - The ATI "Driver-Vehicle Display Apparatus" (US Patent Number 4,716,458) shows the instantaneous cornering/braking/acceleration state of a car with respect to its various limits, overlaid on the "Driver's eye view" video picture. With acceleration/braking as the vertical axis and lateral acceleration as the horizontal axis, various diagrams bit-mapped in PROM are used to represent the driver unwillingness limit, the |
vehicle's control limit, the rollover limit, etc. The actual forward and lateral accelerations experienced by the test vehicle are combined into a moving dot on the screen. The instantaneous relationship between the vehicle and its limits are immediately obvious. The "Video G-G Diagram" has been utilized in demonstrating safety margins in vehicle scene drive-throughs, in showing the severity of lane change maneuvers, and in demonstrating the margins between vehicle handling limits and rollover limits.
Race Car Video G-G - In the adoption of the video G-G diagram, horizontal bar graph representations of throttle and brake are added at the top of the screen, and lap time in a numeric display at the bottom of the screen. The lap time is reset by a radio signal sent by a stopwatch operator at the side of the track. Real-Time Split Image - The output of up to three video cameras can be combined into one composite picture, maintaining the capability for data overlay. Typical applications have a master "driver's eye" view through the windshield, with smaller picture-in-picture views to show disconnected components, wheel lift, etc. The Heitz PIP system is done in real time, using three cameras and one recorder, for economy and to enhance admissibility. |