Registers – Platform operated – Platform actuated traffic counters
Patent
1979-04-02
1982-09-07
Thesz, Joseph M.
Registers
Platform operated
Platform actuated traffic counters
235 92EV, 318318, G06M 304
Patent
active
043485855
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
Technical Field
This invention relates to an apparatus for controlling the speed or frequency of a device by comparing the frequency of the device to a known reference frequency and matching the frequency of the device to the reference frequency.
Background Art
It is often desirable to control the speed or frequency of a device to obtain a desired result. In a laboratory setting for testing engine components off the engine, such as the governor, fuel pump, or injectors for example, it is desirable to control the rotational speed of a hydraulic motor which in turn controls the mechanical operation of the component. It is necessary to control the rotational speed of the hydraulic motor very accurately to insure accurate measurement of fuel flow rates and governor characteristics for example. The torque required to drive the fuel injection system at a steady speed may contain severe cyclic deviations from the average speed. It is therefore desirable to precisely control the rotational speed of the hydraulic motor in a simple, stable manner to be assured of accurate and repeatable test results.
In British Patent Specification No. 1,450,434 published Sept. 26, 1976 Takeshi Hori discloses a phase control apparatus for a rotary member. A rotary disc is connected to the rotary shaft of a motor. The disc has a bar magnet attached thereto whose position is sensed by two angularly displaced pulse generators. The outputs of the pulse generators are fed to a mixer which in turn is fed to a sampling-hold circuit and finally to the motor. When the motor is rotated at a preselected rotational speed, a square wave signal from a generator coincides in time with the signals from the two signal generators. When the motor speed varies, the circuitry adjusts the speed to coincide with the preselected speed. While the apparatus does control the motor speed, it is limited in operation by the positions of the two signal generators with respect to the bar magnet and functions only in response to a certain synchronizing signal. It is desirable to control the rotational speed of the motor by comparing the actual rotational speed with any reference speed.
Disclosure of Invention
In one aspect of the present invention, an integrating frequency-difference counter comprises an up/down counter having an up/down input, a clock input, and an output, and being free to count in response to receiving a clock signal at the clock input, free to count up in response to receiving an up count signal at the up/down input, and free to count down in response to receiving a down count signal at the up/down input; signal generating means for generating first and second clock outputs and first and second count outputs with the clock and count outputs being generated at a preselected frequency in a preselected sequential order; first means for receiving a first reference frequency signal of frequency f.sub.1, combining the first frequency signal with the first clock output in a preselected manner, and producing the clock signal; second means for receiving a second controlled frequency signal of frequency f.sub.2, combining the second frequency signal with the second clock output in a preselected manner, and producing the clock signal; third means for receiving the first sequencer count output and producing the up count signal; and fourth means for receiving the second count sequencer output and producing the down count signals, the output of the counter at any time being the digital quantized form of ##EQU2##
In another aspect of the invention, apparatus for controlling the frequency of a device having a frequency output signal, comprises a frequency controller having an input and being connected to the controlled device; means for generating a reference frequency signal; and an integrating frequency-difference counter having first and second inputs for receiving the reference and output signals and an output connected to the frequency controller.
In another aspect of the invention, an apparatus for controlling the speed of a device
REFERENCES:
patent: 3110853 (1963-11-01), Jones
patent: 3543116 (1970-11-01), Haner et al.
patent: 3548169 (1970-12-01), Togneri
patent: 3724720 (1973-04-01), Bullivant
patent: 3974428 (1976-08-01), Hafle
patent: 3989931 (1976-11-01), Phillips
patent: 4130785 (1978-12-01), Penet
Caterpillar Tractor Co.
Hart Frank L.
Thesz Joseph M.
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