| 摘要 |
<p>A gear speed measuring system which is capable of measuring speeds down to zero, which is capable of use in a ragged environment, and which is relatively insensitive to gear-sensor spacing. The system comprises an electromagnetic sensor (20) connected into the tank circuit of an oscillator (58) to produce an FM signal in which the frequency shifts occur in synchronism with the rotation of a gear (12) or the like. A detector (66) having a reference frequency input (68) converts the FM signal to a digital signal. A microprocessor (48) adjusts the reference frequency (68) as necessary to keep it between the high and low limits of the sensor output. The speed measuring system is applied to the control of the drive unit for a heavy off road vehicle (10) such as a tractor or earth mover. </p> |
