Communications: electrical – Vehicle detectors – Inductive
Patent
1991-06-17
1994-01-11
Swarthout, Brent
Communications: electrical
Vehicle detectors
Inductive
324236, 340933, 340936, 364438, G08G 101
Patent
active
052785556
ABSTRACT:
A determination is made whether a minimum threshold period (or frequency) change has occurred in an oscillator signal indicating the initial presence of a vehicle over an inductive sensor. The change in period of the oscillator signal is measured over each of a plurality of frame segments. A magnitude of period change in the oscillator signal is recorded. If the number of frame segments that occur between detection of the threshold change in period and the magnitude change in period is less than a predetermined number, the detector does not make a speed measurement calculation. If the number of frame segments equals or exceeds the predetermined number, the time rate of change of the period of the oscillator signal is estimated. A vehicle detector calculates a sensor entry distance for a particular vehicle. A vehicle entry time is calculated by dividing the magnitude of period change by the rate of period change. Speed is then calculated by dividing the entry distance by the vehicle entry time. The speed measurement is directed to an output by activating the output for a period of time proportional to the speed of the vehicle. Multiple vehicles may be detected by adjusting the minimum threshold period change, after each vehicle passes, by the peak change in oscillator signal period caused by that vehicle. Vehicle length may be calculated by multiplying the measured speed by the total time between vehicle entry and exit from the loop area, and subtracting the length of the detection area.
REFERENCES:
patent: 3609679 (1971-09-01), Updegraff et al.
patent: 4234923 (1980-11-01), Eshraghian et al.
patent: 4369427 (1983-01-01), Drebinger et al.
patent: 5153525 (1992-10-01), Hoekman et al.
Barte William B.
Griswold Gary L.
Kirn Walter N.
Minnesota Mining and Manufacturing Company
Swarthout Brent
LandOfFree
Single inductive sensor vehicle detection and speed measurement does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Single inductive sensor vehicle detection and speed measurement, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Single inductive sensor vehicle detection and speed measurement will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1634147