RU2067378C1 - Device to check speed of rotation of working members of agricultural machines - Google Patents

Abstract

FIELD: agricultural engineering. SUBSTANCE: rotation speed pickup forms pulses by signal reflected from strip whose frequency corresponds to speed of shaft rotation. Signal of pickup is converted in control unit and multiplier and is compared with signal from standard frequency pulse generator. Speed of shaft rotation is evaluated basing on comparison of results. Data are displaced. EFFECT: enhanced reliability of checking. 5 cl, 2 dwg

Description

 The alleged invention relates to agricultural machinery and is intended, in particular, to control the frequency of rotation of the shafts of a combine harvester.

 A known device for controlling the speed of the working bodies of a combine harvester containing pulse generators, the control inputs of which are connected to the outputs of the speed sensors, an alarm element, an element or an amplitude detector and key elements (USSR, AS N 106967, class A 01 D 41/12, 1984).

 The disadvantage of the known device is limited operational capabilities, because the known device does not allow to determine the absolute value of the rotational speed of the controlled shaft. It should be noted that when setting the combine harvester to the specified operating mode, the speed of the threshing drum and the cleaning fan are regulated. In this case, each adjustment requires a measurement of the rotational speed of the threshing drum and the cleaning fan. The known device allows only threshold frequency control, but this is not enough when restructuring the operating mode of the combine. This limits the operational capabilities of the known device.

 There is another device for controlling the rotation of the working bodies of an agricultural machine, containing a pulse counter with an indicator on the output, a speed sensor, a pulse generator of a reference frequency (USSR, AS N 1375171, class A 01 D 41/12, 1988).

 The known device has the disadvantages indicated above.

 The purpose of the proposed invention is the expansion of the operational capabilities of the device by applying it to adjust the operating modes of the combine harvester.

 To achieve this goal, a frequency multiplier and a control unit are introduced into the device, the first input of which is connected to the output of the speed sensor, the second input of the control unit is connected to the first output of the pulse generator of the reference frequency, the first output of the control unit is connected to the first input of the frequency multiplier, and the second output the control unit is connected to the installation input of the pulse counter, while the second input of the frequency multiplier is connected to the second output of the pulse generator of the reference frequency, and the output of the multiplier pilots at a clock input connected to the pulse counter. The frequency multiplier contains a pulse counter, an AND element, an OR-NOT element, and a trigger, the first input of which is the input of the frequency multiplier, and the second trigger input, combined with the first input of the OR-NOT element, is the second input of the frequency multiplier, the trigger output is connected to the installation input the pulse counter and the second input of the OR-NOT element, the output of the OR-NOT element is connected to the clock input of the pulse counter, while the outputs of the pulse counter through the And element are connected to the installation input of the trigger. The speed sensor contains a pulsed light source, a photodetector and series-connected pulse amplifier, a detector and a key amplifier, and the output of the photodetector is connected to the input of the pulse amplifier through an isolation capacitor. The pulse generator of the reference frequency is made in the form of a generator with quartz frequency stabilization and a frequency divider, the input of which is connected to the output of a generator with quartz frequency stabilization. The control unit contains a trigger, a pulse counter with a decoder at the output, an AND element, an OR element, and an inverter, the input of which is the first input of the control unit, and the clock input of the pulse counter is the second input of the control unit, the output of the And element is the first output of the control unit, and the output element OR the second output of this block.

 These features distinguish the proposed device from our chosen prototype and ensure its compliance with the criterion of "Novelty." In the description of the above analogues, an analysis was made on the conformity of our proposal to the criterion of "Significant differences". The general, particular, essential features of the proposal are analyzed. Similar to them signs of the known listed solutions in combination with the others do not allow to obtain a positive effect, similar to the one proposed. Therefore, our solution meets the criterion of "Significant differences".

 In FIG. 1 shows a diagram of a device for controlling the frequency of rotation of the working bodies of an agricultural machine. In FIG. 2 shows a block diagram of a speed sensor.

 The device contains a counter 1 pulses, the output of which is connected to a digital indicator 2 (the binary code decoder in the seven-segment code is part of the counter 2). The pulse generator 3 of the reference frequency is made on the basis of a generator 4 with quartz frequency stabilization and a pulse frequency divider 5, pulses of the generator 4. The speed sensor 6 contains a pulsed light source formed by the LED 7 and the pulse generator 8 (Fig. 2). The photodetector 9 through a capacitor 10 is connected to the input of the amplifier 11 pulses. A key amplifier 13 is connected to the output of the amplifier 11 through an amplitude detector 12. A photocouple of elements 7 and 9 interacts with a reflective strip 14 glued to the monitored shaft 15. The strip 14 is made with respect to the shaft 15 from color-contrasting material, for example, from white paper or adhesive plaster. The output of the sensor 6 is connected to the first input of the control unit 16. The second input of block 16 is connected to the first output of generator 3. Block 16 includes a trigger 17, a pulse counter 18 with a decoder at the output made on element I 19, element OR 20, element I 21, a circuit from capacitor 23 and resistor 24 together with the element 20 forming an initial state setting circuit.

 The circuit of the capacitor 25 and the resistor 26 together with the element 21 forms a gated shaper of short pulses. The first output of block 16 is connected to the first input of the frequency multiplier 27, and the second output of block 16 is connected to the installed input of counter 1. The elements of block 16 are interconnected in accordance with FIG. 1.

 The multiplier 27 comprises a pulse counter 28 with an AND element 29 at the output, an OR-NOT 30 element, and a trigger 31. The elements are interconnected in accordance with FIG. 1. The output of the multiplier 27 is connected to the clock input of the counter 1. The device is powered from an autonomous source 32, which is built into the control device. Power on is performed by button 33 (power bus of functional units are not shown).

 The control device operates as follows. To start the measurements, the sensor 6 is positioned so that the distance between the controlled shaft 15 and the working surface of the photocouple from elements 7 and 9 is 60-80 mm, which ensures reliable registration of reflected light pulses. By pressing button 33, a supply voltage + E is supplied to all functional units of the device. In this case, the elements 20, 23, 24 form a short pulse, by which the counter 1 trigger 17 and the counter 18 are set to zero. Generator 4 generates rectangular rectangular pulses with a high frequency of 32768 Hz), and at the output of divider 5, standard pulses with a frequency of 1 Hz are formed. The generator 8 generates pulses with a frequency of several tens of kHz supplying the LED 7. At each rotation of the shaft 15, light pulses are reflected from the strip 14, as a result of which pulse packets are formed at the output of the photodetector 9, which are amplified by the amplifier 11. The isolation capacitor 10 does not pass a constant to the input of the amplifier component of the output signal of the photodetector 9, due to exposure to the photodetector of daylight, which allows you to use the device in the field. After detecting the amplified bursts of pulses by the detector 12 and amplifying the detected pulses with a key amplifier 13, a rectangular pulse with a shaft speed of 15 is obtained at the output of the sensor 6.

где
n число оборотов в минуту вала 15;
m число импульсов на выходе датчика 6 за эталонный интервал времени Δt.The operation of the control device is based on the ratio

Where
n the number of revolutions per minute of the shaft 15;
m the number of pulses at the output of the sensor 6 for the reference time interval Δt.

 From the point of view of the convenience of the hardware implementation of the device and the acceptable control time, D628,05022158,10t 4 sec was selected.

In this case, expression (1) takes the form
n 15 xm (2)
In accordance with the expression (2), the multiplier of the frequency of the pulses by the multiplier 27 is chosen equal to 15.

 The first pulse from the output of the sensor 6 in the trigger 17 is recorded "1", and the counter 18 is prepared for the calculation of the reference pulses with a frequency of 1 Hz.

 As a result of this, at the output of the third discharge of the counter 18, a measuring interval is formed in the form of a positive pulse, lasting 4 seconds. This pulse prepares element 21 for the formation of short pulses from the output pulses of the sensor 6. Elements 25 and 26 are selected so that the duration of the generated pulses is equal to 2-3 periods of pulses at the output of the generator 4.

 The first pulse at the output of element 21, formed after the start of the measuring interval, sets the trigger 31 to "1", as a result of which element 30 begins to transmit reference pulses from the generator 4 to the input of counters 1 and 28. After 15 pulses have passed, "1 is formed at the output of element 29 ", by which the trigger 31 is set to" 0 "and the pulse counting is stopped. The next pulse from the output of the element 21 of the trigger 31 is again set to "1" and the described counting process is repeated until a measurement interval of 4 seconds acts on the first input of the element 21. Thus, counter 1 accumulates a number equal to the product of number 15 and the number of pulses transmitted from sensor 6 over an interval of 4 seconds. In accordance with expression (2), this number characterizes the number of revolutions of the controlled shaft per minute.

 After the end of the measuring interval, the pulse count ends, and on the indicator 2 the number stored in counter 1 is displayed. The output of the measurement results continues for 4 seconds, after which, at the output of element 19, "1" is formed, which through the element 20 of counter 1 and 18 are set to zero and a new cycle of pulse counting from the sensor 6 begins, which also lasts 4 seconds. Then, within 4 seconds, the monitoring results are again displayed on indicator 2. This process continues cyclically until button 33 is pressed, and sensor 6 interacts with shaft 15.

 After completing the measurements, the button 33 is released and the device turns off.

 At NPO VISKHOM, laboratory tests of the prototype of the described control device were carried out. The layout was implemented using integrated circuits of the 176 and 561 series. As a digital indicator, a liquid crystal indicator of the type IZhTS 5-4 / 8 was used. The rotational speed sensor is implemented using an AL107B LED, an FDK 263 photodiode, KT3102, KT3156 transistors and KR1006VI1 and K548UN1A microcircuits. As a power source, a Krona battery was used. The model is made in a metal case with overall dimensions of 200 x 45 x 75 mm, at the end of which a speed sensor is mounted. Laboratory tests confirmed the reliable operation of the control device in both daylight and artificial lighting conditions and showed the feasibility of using the proposed device for the operational control of the shaft speed of agricultural machines, as well as other machines where such control is necessary.

Claims (5)

 1. The control device of the rotational speed of the working bodies of the agricultural machine, containing a pulse counter with an indicator on the output, a rotational speed sensor, a pulse generator of a reference frequency, characterized in that a frequency multiplier and a control unit are introduced into it, the first input of which is connected to the output of the rotational speed sensor , the second input of the control unit is connected to the first output of the pulse generator of the reference frequency, the first output of the control unit is connected to the first input of the frequency multiplier, and the second output of the unit board connected to the installation input of the pulse counter, while the second input of the frequency multiplier is connected to the second output of the pulse generator of the reference frequency, and the output of the frequency multiplier is connected to the clock input of the pulse counter.  2. The device according to claim 1, characterized in that the frequency multiplier comprises a pulse counter, an AND element, an OR element, and a trigger, the first input of which is the input of the frequency multiplier, and the second trigger input, combined with the first input of the OR element, is the second the input of the frequency multiplier, the trigger output is connected to the installation input of the pulse counter and the second input of the element OR NOT, the output of which is connected to the clock input of the pulse counter, the outputs of which through the element And are connected to the installation input of the trigger.  3. The device according to claim 1, characterized in that the rotation speed sensor comprises a pulsed light source, a photodetector and sequentially mounted pulse amplifier, a detector and a key amplifier, and the output of the photodetector is connected to the input of the pulse amplifier through an isolation capacitor.  4. The device according to claim 1, characterized in that the pulse generator of the reference frequency is made in the form of a generator with quartz frequency stabilization and a frequency divider, the input of which is connected to the output of the said generator.  5. The device according to p. 1, characterized in that the control unit comprises a trigger, a pulse counter with a decoder at the output, an AND element, an OR element, and an inverter, the output of which is the first input of the control unit, and the clock input of the pulse counter is the second input of the control unit , the output of the AND element is the first output of the control unit, and the output of the OR element is the second output of this block.

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