JPS5918460A - Drive wheel revolution meter - Google Patents

Abstract

PURPOSE:To enable the measurement of correct revolutions quickly by calculating revolutions from the results of counting as counts of clock signals having an amply short cycle are generated each time output signals of a sensor are memorized. CONSTITUTION:When a revolutions meter starts, the flow shifts to the step 100 and operation at the step 101 is preformed. The state is reached as shown by the step 102 where the output terminal 10c receives a signal to be supplied. Upon the end of a signal a1, a judgement is done at the step 103 but at this point, as data alone is memorized into a memory 5, NO is given requiring shift to the step 104. As the cycle of signals is generally several millisecond, the judgement at the step 104 gives ON and a circulation is required in a loop through steps 102, 103 and 104 until a signal is supplied again, while a signal b1 is supplied at some step. When a signal a2 is generated, data is all set for the memories used as shown by the step 105. After the end of computation at the step 107, a judgement is done as shown by the step 108 and operation at the step 109 is performed, followed by return to the step 101. Thus, measurement can be done simply and economically.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drive wheel rotation speed meter for measuring the rotation speed of the drive wheels of a vehicle in which the drive wheels are individually driven.

Generally, agricultural equipment drives left and right drive wheels individually, so depending on the road surface condition, one of the drive wheels may slip, causing the left and right drive wheels to rotate at different speeds. If this difference in the number of rotations of the drive wheels becomes too noticeable, there will be a lot of work loss and it is also dangerous, so it is necessary to measure and display the number of rotations of the drive wheels.

For this reason, conventionally, signals generated according to the rotational speeds of the right and left drive wheels were counted and displayed using separate counters.

However, since the rotational speed of the drive wheels of agricultural equipment is approximately 1 to 88 rotations per minute, the rotational speed cannot be measured unless an argument of about 1 minute is given. If the rotation speed fluctuates, it will not be possible to accurately measure the rotation speed. Furthermore, since the driving wheel rotational speed was measured using separate counters, it was not economical.

Therefore, an object of the present invention is to provide a driving wheel rotation speed meter that can accurately measure rotation speed in a short time and is economical.

In order to achieve such an object, the present invention stores the count value of a counter that counts clock signals having a cycle sufficiently shorter than the cycle of the output signal of the sensor each time the output signal of the sensor is generated, and stores this count result. The rotation speed is calculated from the following. Hereinafter, the present invention will be described in detail using drawings showing embodiments.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In the figure, reference numeral 1 indicates a first sensor that generates, for example, 32 pulses when the left drive wheel rotates once, as an output signal corresponding to the rotational speed of the first drive wheel, and reference numeral 2 indicates a second drive wheel. This is a second sensor that generates a pulse as an output signal corresponding to the rotation speed of the right drive wheel in the same manner as the right drive wheel. 3 is an OR circuit that generates an output signal when either the first sensor 1 or the second sensor 2 generates a pulse.

4 is a counter that constantly counts a clock signal with a cycle sufficiently shorter than the cycle of pulses generated from the first sensor 1 and the second sensor 2, and starts counting from zero again when the counted value overflows. 5 to 8 are 1st and 2nd
．． Third. The fourth memory 9 is a display section. Reference numeral 10 denotes a control unit that determines whether the signal supplied to the input terminal 10a is generated from the sensor 1 or the sensor 2, based on the signal supplied to the input terminal 10a or 10b. Then, the count value of the counter 4 at the time when the signal is first supplied from the sensor 1 is stored in the memory 5, and the count value of the counter 4 at the time when the signal is supplied next is stored in the memory 6. Further, the count value of the counter 4 at the time when the signal from the sensor 2 is first supplied is stored in the memory 7, and the count value of the counter 4 at the time when the signal is supplied next is stored in the memory 8. Then, if the data is stored in all of the memory 5 to memory 8, or after a predetermined period of time (for example, 1 second) has passed since the data was first stored in the memory 5 to memory 8, the data in the memory 6 is transferred to the memory 5. The rotation speed of the left drive wheel is calculated by subtracting the data and multiplying that value by a predetermined number. Further, the data in the memo IJ 7 is subtracted from the data in the memory 8 and the subtracted value is multiplied by a predetermined number to calculate the rotation speed of the right drive wheel. Then, a signal of the calculated rotational speed is supplied to the display unit 9, so that a display 91 displays the rotational speed of the left driving wheel, and a display 92 displays the rotational speed of the right driving wheel.

The tachometer according to the present invention configured in this way has a second
The operation when a pulse generated from the left drive wheel shown in FIG. A and a pulse generated from the right drive wheel shown in FIG. 2B are supplied will be explained using the flowcharts of FIGS. 3 and 4. When the tachometer starts operating, the flow goes to "memory clear" as shown in step 100.
The stored data from memory 5 to memory 8 is cleared.

When the memory is cleared, the flow performs the "set timer to zero" operation shown in step 101, sets the internal timer of the control unit 10 to zero, and then enters the "interruptable" state shown in step 102. Nashi, control unit, 10 is input terminal 10
The signal supplied to c is now accepted.

Since the period of the signal supplied to the input terminal 10c changes depending on the rotation speed of the driving wheels, the timing of its occurrence is uncertain. It is conceivable that the control unit 10 can always process this signal, but the processing of this signal is only necessary for a limited period, and the input terminal 10c is used for other periods.
There is no need to process the signals supplied to the . In addition, the control unit 1
Since 0 is also performing other operations to operate the agricultural machine, the control section 10 is required to process the signal supplied to the input terminal 10c, and only when this signal is supplied does it perform other operations. It enters an interrupt state in which it stops and processes the supplied signal, and other operations can be performed at other times. Therefore, after the "interrupt enabled" state in step 102, the control unit 10 immediately enters the interrupt state when a signal is supplied to the input terminal 10c, and in step 105, which will be described later.
After the "interrupt prohibited" state, the device is configured so that an interrupt state does not occur even if a signal is supplied to the input terminal 10c.

As described above, the sensors 1 and 2 generate signals as shown in FIGS. 2A and 2B. In step 102, for example, the second
When the signal al shown in FIG. A is supplied to the input terminal 10c of the control section 10, the control section 10 enters an interrupt state, interrupting all other processes and processing this signal. The flow at this time is not equivalent to the interrupt processing shown in FIG. 4, and it is determined whether the input signal is only the left side signal shown in step 200.

This judgment is made based on the signals supplied to the input terminals 10a and IQb of the control unit 10. As shown in FIG. 2, when the signal a1 in FIG. 2A is generated, the signal a1 in FIG.
No signal is generated. Therefore, in step 200, "Is it only the left signal?" is YES.In Step 2, the judgment "Is this the first signal on the left?" shown in the previous step is made.
Since this is the first signal for the left drive wheel, this determination is YES. As a result, the control section 10 performs the operation of "storing the count result in the memory 5" shown in step 202, so that the count value of the counter 4 at the time when the signal al is supplied is stored in the memory 5. When the operation in step 202 is completed, the interrupt operation is completed and the flow returns to step 102 at the time when the interrupt occurred.

The control unit 10 receives the signal a1 supplied to the input terminal 10c.
When the process is completed, a determination is made in step 103 as to whether the data is complete. This is memory 5 to memory 8
It is determined whether all the data has been stored up to this point, but since the data has only been stored in the memory 5 at this point, this determination is NO and the flow moves to step 104. Step 104 is the step 10 described above.
It is determined whether one second has passed after the start of the operation No. 2. Generally, the period of the signals shown in Figures A and H of M2 is several milliseconds, so at this point, that is, the signal a1 of Figure 2A
When the process ends, the determination in step 104 becomes NO.

As a result, the flow circulates through the loop of steps 102, 103 and 104 until a signal is again supplied to the input terminal 10c of the control unit 10. As this circulation is repeated, the signal b1 is eventually supplied to the input terminal 10c of the control section 10 at some step among steps 102 to 104 as shown in FIG. 2B. As a result, the flow moves to step 200 again, but since this signal is a signal for the right drive wheel, the answer to "Only left signal?" in step 200 is NO, and the flow moves on to step 203. Here, it is determined whether it is only the right signal, and this determination is YES, and then it is determined in step 204 whether it is the first right signal.
Since the answer is YES here as well, the operation of "store count result in memory" shown in step 205 is performed. This is similar to the operation in step 202 described above, and the signal b
After the count value of the counter 4 at the time when l is supplied is stored in the memory 7, the process returns to the step at the time when the interrupt occurred.

Thereafter, in the same way as the above-mentioned operation, the flow during the period when no signals are generated from the sensors 1 and 2 is in steps 102 to 104.
cycle through the loop. On the other hand, when the signal b2 is generated, the count value of the counter 4 at this time is stored in the memory 8 as shown in step 206, and when the signal IL2 is generated, the count value of the counter 4 at this time is stored in the memory 8 as shown in step 207. is stored in the memory 6 as follows. Then, each time the hand value of the counter 4 is stored in each memory, in step 103, [
It is determined whether the data is complete, but at the time when the signal a2 shown in FIG. 105, the state is "interrupt prohibited". Therefore, the control unit 10 receives the signal supplied after step 105, for example, the signal '3 + b in FIG.
3 + b4 will no longer be accepted.

After that, the control unit 10 performs "rotation speed calculation" shown in step 107. This calculation subtracts the data stored in the memory 5 from the data stored in the memory 6, and then multiplies it by a predetermined constant to calculate the rotation speed of the left drive wheel.
stored in internal registers. Also note the rotation speed of the right drive wheel IJ7. A similar calculation is performed using the data stored in the memory 8.

When the control unit 10 completes the rotation speed calculation shown in step 107, it makes a determination as to whether "2 seconds have passed" shown in step 108, and this judgment is made when the time from the start of the rotation speed calculation is 2
If it is longer than seconds, the answer is YES. Therefore, the control section 10 performs the "display" operation shown in step 109, and supplies the data stored in the internal register of the control section 10 to the indicators 91 and 92 of the display section 9 to display the rotation speed. After that, return to step 1, "Set the timer to zero."

Therefore, the operations from steps 102 to 109 are repeated again, new data is stored from the memory 5 to the memory 8, and the number of revolutions calculated based on this data is displayed on the display section 9 every two seconds.

Note that the determination of "Has 1 second elapsed" in step 104 is made to detect the stored data from memory 5 to memory 8 in 1 second even if the signal from one of the drive wheels is no longer generated due to some reason. It will be discontinued. Lost, step 1
The determination as to whether 2 seconds have passed in step 08 prevents the rotation speed display time from becoming irregular due to deviation in the rotation speed calculation time, and prevents eye fatigue due to the short display time.

The above operations are explained when the timing of the signals generated from the right or left drive wheels is different, but in reality, they may occur simultaneously as in all to a13 and 'b11 to b13 in Figure 2. be. In this case, since signals are supplied from both drive wheels, the determinations at steps 200 and 203 are both NO. Therefore, the control unit 10 regards the signal supplied to the input terminal 10c in step 208 as a signal from the right drive wheel, and stores the count value of the counter 4 at the time of the first signal generation as shown in step 209. 7, and the count value of the counter 4 when the next signal is generated is stored in the memory 8 shown in step 210. after that,
In step 211, the control unit 10 inputs the input terminal 10c.
The signal supplied to the left drive wheel is regarded as the signal from the left driving wheel, and the counting result of the counter 4 is similarly calculated in steps 212 and 213.
The rotation speed is stored in the memory 5 and the memory 6 as shown in FIG.

When the drive wheels are rotating, the minimum number of rotations is about 91 times per minute, but the number of signals generated from sensors 1 and 2 is generally about υ32 times per rotation of the drive wheels. It is configured as follows.

For this reason, the sensor installed on one drive wheel sends out a signal at maximum intervals of 2 seconds. Then, the number of rotations is calculated based on the count value of the counter 4 that has changed during this time, and the display is also updated every two seconds. Therefore, even when the drive wheel rotates at its slowest speed, the rotation speed is calculated and displayed every two seconds, which is 30 times faster than the conventional method, which counts every minute. . This means that changes in the rotational speed can be seen immediately, making it possible to know the rotational speed much more accurately than in the past.

As explained above, the driving wheel rotation speed meter according to the present invention,
Among the count values of a counter that counts clock signals having a cycle that is sufficiently shorter than the repetition cycle of the signal generated from the sensor, it in the cycle of the signal generated from the sensor
Since it extracts the amount of change in numerical values and calculates the rotation speed based on this data, accurate rotation speed can be measured in a short time, and the configuration is simple, making it economical. Has excellent effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the waveform of a signal generated from a sensor, and FIGS. 3 and 4 are flow charts for explaining the operation. 1.2...Sensor, 3-...OR circuit, 4...
...Kara〉'Yu, 5-8.Fist...Memory, 9..Display section, 10..Control section. Patent applicant: G-Eco Co., Ltd. Agent: Masaki Yamakawa (and one other person)

Claims (1)

[Scope of Claims] A first sensor that generates a signal according to the rotation speed of the first drive wheel, a second sensor that generates a signal according to the rotation speed of the second drive wheel, and a first sensor that generates a signal according to the rotation speed of the second drive wheel. and an OR circuit that generates an output signal when a signal is generated in at least one of the second sensors, and a clock signal whose cycle is sufficiently shorter than the cycle of the signal output from the first and second sensors. a counter; Second. Third. A fourth memory determines whether the output signal from the OR circuit is generated from the first sensor or the second sensor based on the signals from the first and second sensors. . storing in the first memory the count value of the counter at the time when the first signal generated from the fourth sensor is supplied;
The count value of the counter at the time when the next generated signal is supplied from the first sensor is stored in the second memory, and the count value of the counter at the time when the first generated signal is supplied from the second sensor is stored in the second memory. A count value is stored in the third memory, and a count value of the counter at the time when the next generated signal is supplied from the second sensor is stored in the fourth memory. When data is stored in all of the first to fourth memories, or a predetermined period of time has elapsed since the count value of the counter was stored in any of the first to fourth memories. a control unit that calculates the rotational speed of the first drive wheel and the second drive wheel based on data stored in the first to fourth memories; and a display unit that displays the calculation results. A driving wheel rotation speed meter comprising: