JPH0119084B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for detecting the position and speed of an object using a fixed position detection signal generated by a detector in accordance with the movement of the object, and particularly relates to a method for detecting the position and speed of an object using a fixed position detection signal generated by a detector according to the movement of the object. This invention relates to a position and speed detection method for obtaining position and speed signals.

2. Description of the Related Art A method using a rotary encoder, a linear encoder, or the like is known as a method for detecting the position and speed of a motor and an object driven by the motor.

For example, a rotary encoder is attached to the rotating shaft of a motor, and as the shaft rotates, the rotary encoder
It generates two-phase sine wave signals of A phase and B phase with a phase difference of 2, and the frequency of the sine wave signal is proportional to the rotational speed of the motor. This A, B, 2
A position (displacement) signal and a velocity signal are usually detected from the phase sine wave signal as follows.

Fig. 1 is a block diagram of a conventional circuit that generates position and velocity signals from the above sine wave signal, and Fig. 2 is a waveform diagram of each part thereof, where M is a motor, RE is a rotary encoder, and PG is a two-phase sine wave signal. A pulse generator that generates a pulse every time A and B cross zero volts. PD determines which of the sine wave signals A and B is leading or not, and if the A phase signal is leading, it is added. a phase detector that provides a signal, or a subtracted signal if delayed, to an up/down counter UDC;
The UDC is an up/down counter that converts the pulse generator according to the addition and subtraction signals from the phase detector.
DA is a device that counts up and down the pulses generated from PG, DA is a DA converter that converts the contents of the up and down counters into digital-to-analog (referred to as DA conversion), and generates a position signal PS, FVC.
is an FV converter which receives pulses generated from the pulse generator PG, converts the pulse frequency from frequency to voltage, and generates a speed signal.

Now, for example, if the motor is rotating clockwise, gradually decelerating, and then reversing its rotational direction at time to, the phase of the A-phase signal from the rotary encoder RE will initially be as shown in Figure 2 A and B. Two sine wave signals are generated which are ahead of the B phase by π/2.

Phase detector PD detects this and provides addition signal AD to up/down counter UDC. On the other hand, the pulse generator PG generates an up pulse UPP every time the A-phase and B-phase sine wave signals cross zero volts.
Up/down counter UDC and FV converter
Enter into FVC.

Up/down counter UDC is up pulse
Every time UPP arrives, it counts up by 1,
The contents are input to a DA converter and DA converted.
Therefore, until time to, the position signal PS advances stepwise as shown in FIG. 2, while the speed signal VS attenuates stepwise. After time to, the rotation direction of the motor is reversed, so the A-phase signal lags behind the B-phase signal, so the phase detector PD generates a subtraction signal SB, and the pulse generator PG generates a down pulse DNP. The contents of the up/down counter are then subtracted.
Therefore, after time to, the position signal PS becomes a signal that decreases stepwise, and the speed signal VS increases stepwise in the negative direction.

In this way, according to the conventional method, the position signal PS,
Both the speed signals VS had a step-like shape, and it was not possible to obtain position and speed signals that changed smoothly. By the way, even in the flat parts of PS and VS, the motor is actually rotating and the speed is changing. That is, the above method has a drawback in that very detailed position and velocity signals cannot be obtained.

Recently, the following methods have been attempted to solve the above-mentioned drawbacks.

In FIG. 3, 1 is a moving object or a rotating body whose position and velocity are to be measured; 2 is a detector that outputs position detection signals A and B, which are sinusoidal signals having a phase difference of 1/4 period; and 3 is the amplitude that subdivides the 1/2 period of the part close to the center level of the amplitude of the moving distance of one cycle of the position detection signal A, and sets the amplitude comparison level for the position detection signal corresponding to each divided position. A comparison level setting circuit 4 sets an amplitude comparison level for the position detection signal B; 5 compares the amplitude comparison level set by the amplitude comparison level setting circuit 3 with the position detection signal A; A comparison circuit that outputs a signal; 6 a comparison circuit that compares the amplitude comparison level set by the amplitude comparison level setting circuit 4 with the position detection signal B and outputs a comparison signal; 7 a comparison circuit output from the comparison circuit 5; A comparison signal change detection circuit which detects a signal, generates a change signal according to the change, detects whether the position detection signal A has changed in an increasing direction or a decreasing direction, and outputs a change sign; 8 is from the comparison circuit 6; A comparison signal detection circuit outputs a change signal and a change sign for the output comparison signal and position detection signal B, 9 is an OR circuit for each change signal output from comparison signal change detection circuits 7 and 8, and 10 is a position detection circuit. A moving direction detecting circuit inputs each change signal and each change sign outputted from the signals A and B and the comparison signal change detecting circuits 7 and 8, and outputs a movement or rotation direction signal of the object; 11 is an up/down counter; , 12 is FV
The converter 13 is a DA converter.

FIG. 4 is a diagram explaining the principle of amplitude comparison level determination. Figure 5 shows the amplitude comparison level setting circuit in Figure 3;
Detailed diagram of a comparison circuit and a comparison signal change detection circuit. 6th
The figure is a detailed diagram of the moving direction detection circuit in FIG. 3.
FIG. 7 shows an operation time chart in FIG. 3.

The detector 2 responds to the movement of the moving or rotating object 1.
Position detection signals A and B are output from. In this case, the position detection signals A and B are sinusoidal waveform signals. The position detection signal A is led to a comparison circuit 5, where it is compared with the amplitude comparison level of the amplitude comparison level setting circuit 3.

The principle of determining the amplitude comparison level is as shown in Figure 4, where one cycle of the position detection signal is divided into 20 equal parts.
Of the levels corresponding to each of the 20 equally divided positions, the levels of the portion close to the center level AV2 of the low width are set as the five amplitude comparison levels AV0 to AV4.

As shown in FIG. 5, the amplitude comparison level setting circuit 3 divides the constant voltage AV0 and the constant voltage AV4 by a resistor to set a total of five levels AV0 to AV4. The comparison circuit 5 includes five comparators 4-0~
4-4, each of which compares the amplitude comparison levels AV0 to AV4 with the value of the position detection signal and outputs a change detection signal as shown in the time chart of FIG.

Comparison signal ALV0 from comparators 4-0 to 4-4
~ALV4 is D type flip-flop 7-10
~7-14, and is set by the clock CLK, which has a sufficiently faster cycle than the change in the position detection signal.

The output of this flip-flop NEW0A~
NEW4A is input to the programmable read-only memory (PRM), and at the same time, it is also input to flip-flops 7-20 to 7-24 and set by the clock CLK. D type flip-flop 7-20~7-24 output LD0A~
OLD4A is input to PRM. In PRM, 1 of the outputs of flip-flops 7-10 to 7-14
The data LD0A to LD4A before the clock is compared with the current data NEW0A to NEW4A, and if there is a change, a change detection signal (CHANGE A) is generated.
is output as shown in FIG. Furthermore, if this change is in the direction, that is, in the increasing direction of the sine wave, a change sign UPA is output.

The position detection signal B is output from the detector 2 as a signal having a phase different from that of the position detection signal A by 1/4 period. This position detection signal B is inputted to a comparison signal change detection circuit 8 via a comparison circuit 6. The operations of the comparison circuit 6 and the comparison signal change detection circuit 8 are the same as in the case of the position detection signal A described above, and the comparison signal change detection circuit 8 outputs the change detection signal CHANGE.
B is output, and if this change is in the direction, a change sign UPB is output.

Next, the operation of the moving direction detection circuit 10 will be explained. The position detection signal B is input to the comparator 14,
Here, it is compared with the amplitude comparison level and a comparison output tacho pulse B is output. This tacho pulse B and change sign
UPA is input to exclusive OR circuit 16. The output of the exclusive OR circuit 16 passes through the NOT circuit 18 and is input to the AND circuit 19 together with the change detection signal CHANGE A, and the output of the AND circuit 19 is input to the OR circuit 21. Similarly, the position detection signal A is input to the OR circuit 21 via the comparator 15, the exclusive OR circuit 17, and the AND circuit 20.
The OR circuit 21 outputs a moving direction signal indicating the moving (rotating) direction of the object as shown in the time chart of FIG. When the direction of rotation is reversed midway through, the moving direction signal SIGN changes as shown in FIG. The change detection signal CHANGE A from the comparison signal change detection circuit 7 and the change detection signal CHANGE B from the comparison signal change detection circuit 8 are input to an OR circuit 9. Change detection signal from OR circuit 9
CHANGE A+B and moving direction detection circuit 10
The moving direction signal SIGN from the up/down counter 11 is input and counted, and the output of this up/down counter 11 is input to the DA converter 13. Then, the DA converter 13 outputs position information.

Further, the change detection signal CHANGE A+B from the OR circuit 9 and the movement direction signal SIGN from the movement direction detection circuit 10 are input to the FV converter 12.
Speed information is output.

However, the phase difference between the position detection signals A and B has an error of about ±1/10 cycle compared to 1/4 cycle even with a highly accurate detector. is observed in the downward direction,
When attempting to observe the position detection signal A, it is possible that the position detection signal B still exceeds the set amplitude comparison level BV0.

Therefore, if there is no phase difference between the position detection signals A and B, the up/down counter 11 will count 20 counts per cycle, but because of the phase error, it will only count 18 counts per cycle in the example shown in Figure 8. Therefore, accurate position and velocity information cannot be obtained.

The purpose of the present invention is to eliminate the above-mentioned drawbacks, that is, to provide accurate positioning and detection even when the position detection signals A and B generated by the detector have an error of about ±1/10 period with respect to a phase difference of 1/4 period. The purpose is to obtain speed information.

The object of the present invention is to provide a detector that generates periodic two-phase position detection signals A and B having a phase difference of 1/4 period from each other in response to the motion of an object moving or rotating in two directions; For each of the position detection signals A and B, the 1/2 period close to the amplitude center level of the position detection signal within the moving distance of one cycle is subdivided, and the amplitude corresponding to the position detection signal corresponding to each divided position is calculated. a setting circuit that sets a comparison level; a comparison circuit that compares the amplitude comparison level with the amplitude of the position detection signal and outputs a comparison signal; and a comparison circuit that detects a change in the comparison signal to generate a change signal and performs position detection. a comparison signal change detection circuit that detects whether the signal has changed in an increasing direction or a decreasing direction and outputs a change sign; and the position detection signals A and B and each change signal output from the comparison signal change detection circuit. and a movement direction detection circuit that inputs each change sign and outputs a movement or rotation direction signal of the object, and an OR circuit that takes the logical sum of each change signal output from the comparison signal change detection circuit, In a position and speed detecting device that obtains position information and speed information of the object from the output of the OR circuit and a movement or rotation direction signal, the setting circuit is configured to: In addition to the 1/2 cycle near the amplitude center level, an amplitude comparison level is set in a region corresponding to the phase error between the position detection signals A and B, and one of the comparison signal change detection circuits This is achieved by a position and velocity detection device characterized in that the comparison signal change detection circuit is configured to output a change signal and a change sign after completing observation of the maximum value or minimum value of the amplitude comparison level.

An embodiment of the position and speed detection device according to the present invention will be described in detail below.

FIG. 9 is a schematic illustration of a position and speed detection device invented to eliminate the above-mentioned drawbacks, FIG. 10 is a schematic diagram of a position and speed detection device invented to eliminate the above-mentioned drawbacks, and FIG. 10 is a detailed diagram of the amplitude comparison level setting circuit, the comparison circuit, and the comparison signal change detection circuit in FIG. 10. FIG.

FIG. 12 shows an operation time chart in FIG. 10.

The difference in FIG. 11 from FIG. 5 is that the comparison signal change detection circuit 7 includes a negative circuit 24-1 and an OR circuit 2.
4-2 is added to the comparison signal change detection circuit 24, and the amplitude comparison level setting circuit 4 has two amplitude comparison levels.
An amplitude comparison level setting circuit 22 in which BV5 and BV-1 are added, and a comparison circuit 2 in which two comparators corresponding to the above-mentioned additional amplitude comparison levels are added to the comparison circuit 6.
3, and 2 added to the comparison signal change detection circuit 8.
It has a comparison signal change detection circuit 25 which includes four D-type flip-flops corresponding to two comparators and two AND circuits.

The operations and functions of the other parts are the same as those shown in FIG. 5, so their description will be omitted. In each figure, the position detection signal A is mainly considered. Amplitude comparison levels AV4, AV3, AV2, AV1, AV0 set by the amplitude comparison level setting circuit 3
Therefore, the comparison circuits 4-4 to 4-0 detect the position detection signal A.
When observing the comparison signal change detection circuit 24
As a result, a change detection signal CHANGA is output as shown in FIG.

When the amplitude comparison level AV4 finishes observing the position detection signal A in the rising direction or the amplitude comparison level AV0 in the descending direction, the position detection signal B is observed from the NOT circuit 24-1 and the OR circuit 24-2 of the comparison signal change detection circuit 24. During the observation of the position detection signal A, even if the amplitude comparison level of the position detection signal B is observed, the comparison signal change detection circuit 24 does not output the change detection signal CHANGE B.

Therefore, the amplitude comparison level for position detection signal B
In addition to BV0, BV1, BV2, BV3, and BV4, BV
5. By having the amplitude comparison level setting circuit 22 to which BV-1 is added, after the amplitude comparison level AV4 observes the position detection signal A in the rising direction, the amplitude comparison levels BV5 to BV1 change to the position detection signal B having a phase error. When observed in the downward direction, the comparison signal change detection circuit 24 outputs a change detection signal CHANGE B. At this time, by the time the amplitude comparison level BV0 observes the position detection signal B, the amplitude comparison level
Since the AV4 observes the position detection signal A, the change detection signal CHANGE B for the amplitude comparison levels BV0 and BV-1 is not output from the comparison signal change detection circuit 24 due to the above conditions.

Also, the amplitude comparison level AV0 is the position detection signal A.
After observing in the downward direction, the amplitude comparison level BV
-Position detection signal B in which 1 to BV5 have phase errors
When observed in the rising direction, the comparison signal change detection circuit 24 outputs a change detection signal CHANGE B. By the time amplitude comparison level BV4 observes position detection signal B, amplitude comparison level AV0 observes position detection signal A.
4, the change detection signal CHANGE B for BV5 is not output from the comparison signal change detection circuit 24. Therefore, according to the above method, the change detection signal CHANGE B
is output as shown in FIG. Therefore, by repeating the above process, the change detection signals CHANGE A and CHANGE B can be output accurately with respect to position and velocity information even if the position detection signal has a phase error. Next, it is input to the moving direction detection circuit 10. Position detection signal B is comparator 1
4, where it is compared with the amplitude comparison level and outputs a comparison output tacho pulse B. This tacho pulse B and the change sign UPA are input to the exclusive OR circuit 16. The output of the exclusive OR circuit 16 passes through the NOT circuit 18 and is input to the AND circuit 19 together with the change detection signal CHANGE A.
The output of is input to the OR circuit 21. Similarly, the position detection signal A is input to the OR circuit 21 via the comparator 15, the exclusive OR circuit 17, and the AND circuit 20. The OR circuit 21 outputs a moving direction signal indicating the moving (rotating) direction of the object as shown in the time chart of FIG. If the rotation direction is reversed midway, the moving direction signal SIGN is the 12th
Changes as shown in the figure. Change detection signal CHANGE A from comparison signal change detection circuit 24 and change detection signal from comparison signal change detection circuit 25
CHANGE B is input to the OR circuit 9. Change detection signal CHANGE A+B from OR circuit 9 and movement direction signal from movement direction detection circuit 10
SIGN is input to an up/down counter 11 and counted, and the output of this up/down counter 11 is input to a DA converter 13. Then, the DA converter 13 outputs position information.

As explained above, according to the present invention, accurate position and velocity information can be obtained even when two position detection signals have a phase error.

The present invention is not limited to the above-mentioned embodiments, but also when one period is divided into a large number of tens to hundreds, the same effect can be obtained by increasing the amplitude comparison level for a phase error of 1/10 period. is obtained.

Furthermore, in this embodiment, a method has been described in which a method is adopted in which the position detection signal A is used as the main observation method. A similar effect can be obtained by adopting a method of observing both B.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a conventional circuit for generating position and velocity signals. FIG. 2 is a waveform diagram of each part in FIG. 1. FIG. 3 is a reference diagram for explaining the present invention.
FIG. 4 is a diagram explaining the principle of amplitude comparison level determination. Fifth
The figure is a detailed diagram of the amplitude comparison level setting circuit, comparison circuit, and comparison signal change detection circuit in FIG. 3. FIG. 6 is a detailed diagram of the moving direction detection circuit in FIG. 3. FIG. 7 is an operation time chart in FIG. 3. FIG. 8 is an explanatory diagram for explaining the present invention. FIG. 9 is an explanatory diagram for explaining the present invention. FIG. 10 is a schematic diagram of an apparatus according to the present invention. Figure 11 is the 10th
It is a detailed diagram of the amplitude comparison level setting circuit, the comparison circuit, and the comparison signal change detection circuit in the figure. FIG. 12 shows an operation time chart in FIG. 10. In each figure, 1 is a moving object or a rotating body, 2 is a detector, 3, 4, 22 are amplitude comparison level setting circuits,
5, 6, 23 are comparison circuits, 7, 8, 24, 25 are comparison signal change detection circuits, 9, 21 are OR circuits, 1
0 is a moving direction detection circuit, 11 is an up/down counter, 12 is an FV converter, 13 is a DA converter, 14 and 15 are comparators, 16 and 17 are ER circuits, 18 is a negative circuit, and 19 and 20 are AND circuits. It is.

Claims (1)

[Claims] 1. A detector that generates periodic two-phase position detection signals A and B having a phase difference of 1/4 period from each other in response to the motion of an object moving or rotating in two directions; For each of the position detection signals A and B, subdivide 1/2 period close to the amplitude center level of the position detection signal out of the movement distance of one cycle, and correspond to the position detection signal corresponding to each divided position. a setting circuit that sets an amplitude comparison level; a comparison circuit that compares the amplitude comparison level with the amplitude of the position detection signal and outputs a comparison signal; and a comparison circuit that detects a change in the comparison signal to generate a change signal and detects the position. a comparison signal change detection circuit that detects whether the detection signal has changed in an increasing direction or a decreasing direction and outputs a change sign; and the position detection signals A and B and each change output from the comparison signal change detection circuit. A moving direction detection circuit that inputs the signal and each change sign and outputs a movement or rotation direction signal of the object, and an OR circuit that takes the logical sum of each change signal output from the comparison signal change detection circuit. , a position and speed detection device configured to obtain position information and speed information of the object from the output of the OR circuit and a movement or rotation direction signal, wherein the setting circuit is configured to obtain information about the position detection signal A or B or both of the position detection signals A and B; , in addition to the 1/2 period close to the amplitude center level, an amplitude comparison level is set in a region corresponding to the phase error between the position detection signals A and B, and one of the comparison signal change detection circuits: A position and speed detection device characterized in that the other comparison signal change detection circuit is configured to output a change signal and a change sign after completing observation of the maximum value or minimum value of the amplitude comparison level.