JPH1019920A - Device for detecting movement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for detecting movement which outputs the signals of moving direction for measuring the pulse signals of movement and the moving direction for measuring the moving speed of a movable body without malfunctions. SOLUTION: This device for detecting movement consists of a displacement detector 11 which generates the displacement signals of a plurality of phases varying smoothly responding to the movement of a movable body, a reshaping unit 12 which generates three phrases of reshaping signals A, B and C responding to the output signals of the displacement detector 11, a movement pulse generating unit 13 which removes the noise at the time of changes in the level of the movement pulse signal through the use of the two phases of shaping signals A and B and obtains movement pulse signals synchronized to the reshaping signal A or the reshaping signal B, and moving direction generating unit 14 which obtains the moving direction signals according to the level of the reshaping signal C at the time of changes in the level of the movement pulse signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movement detection device for outputting a movement pulse signal for measuring a movement speed of a moving body and a movement direction signal for measuring a movement direction.

[0002]

2. Description of the Related Art In recent years, in order to measure the rotation speed of a rotating body, a waveform shaper for obtaining a pulse signal obtained by shaping the waveform of an AC signal that changes in synchronization with the rotation of the rotating body has been used as a rotational movement detecting device. (For example, see JP-A-63-25).
No. 6013).

FIG. 5 shows a configuration of a conventional detecting device for detecting rotational movement. First comparator 511 without hysteresis
Receives an AC signal 501 synchronized with the rotation of the rotating body and generates a shaped signal 502 obtained by comparing and shaping the AC signal 501. Similarly, the second comparator 512 having a predetermined hysteresis width by the resistors 532 and 533 outputs the AC signal 5
01 is generated with a predetermined hysteresis width to produce a shaped signal 503. The shaping signals 502 and 503 are input to the pulse generator 513, and output a pulse signal 504 in which a level transition occurs for a time width from a rising edge of the shaping signal 502 to a rising edge of the shaping signal 503. As a result, the rotation speed of the rotating body can be measured based on the cycle of the pulse signal 504.

[0004]

However, the configuration of the above-mentioned conventional detecting device has the following problems.

(1) Since the first comparator 511 and the second comparator 512 are used for shaping the same AC signal 501, the configuration is complicated.

In order to simplify this, for example, it is conceivable that only the first comparator 511 without hysteresis is provided and the second comparator 512 and the pulse generator 513 are eliminated. Shaped signal 50 of the comparator 511
2 becomes the output pulse signal. However, since the first comparator 511 has no hysteresis, the input AC signal 50
1 causes many noise pulses having a very small time width at the time of occurrence of the edge of the shaping signal 502, and cannot be used for speed measurement.

[0007] In order to simplify noise while being strong, for example, a second comparator 51 having hysteresis is used.
2, the first comparator 511 and the pulse generator 513
In this case, the shaped signal 503 of the second comparator 512 having hysteresis becomes an output pulse signal. However, since the second comparator 512 has hysteresis, the point of occurrence of the edge of the shaped signal 503 is shifted from the point of zero crossing of the input AC signal 501 by the amount of hysteresis, and the amplitude modulation component included in the AC signal 501 is changed. As a result, the pulse width and pulse period of the shaping signal 503 fluctuate, and sufficient speed measurement accuracy cannot be obtained.

(2) If noise exceeding the hysteresis width of the second comparator 512 is included in the input AC signal 501, a malfunction (noise pulse) occurs. In particular, since the amplitude of the AC signal 501 varies during mass production,
It was necessary to set the hysteresis width sufficiently smaller than the minimum amplitude in mass production, and the margin for noise was insufficient.

(3) The above conventional detection device does not detect the direction. SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described conventional problems, and to provide a movement detection device that obtains a movement pulse signal for measuring a movement speed and a movement direction signal for measuring a movement direction with a simple configuration. Is to do.

[0010]

SUMMARY OF THE INVENTION A movement detecting apparatus according to the present invention comprises three-phase digital shaped signals A,
The shaping means for generating B and C and the shaping signal A and B for two phases are used to remove noise at the time of the level change of the moving pulse signal, and the movement synchronized with the shaping signal A or the shaping signal B is performed. The apparatus comprises moving pulse generating means for obtaining a pulse signal, and moving direction generating means for obtaining a moving direction signal corresponding to the level of the shaping signal C at the time when the level of the moving pulse signal changes.

Since the moving pulse signal is generated by the shaping signals A and B for two phases, noise contained in the shaping signal A or B is removed, and the moving pulse signal synchronized with the shaping signal A or the shaping signal B is removed. A pulse signal can be created. Therefore, even if the output signal of the displacement detecting means for generating the shaping signal A and the shaping signal B contains a considerable noise, a malfunction (noise pulse) does not occur in the moving pulse signal. That is, the noise margin becomes extremely large. Further, by obtaining a moving direction signal corresponding to the level of the shaping signal C of the third phase at the time when the level of the moving pulse signal changes, accurate detection of the moving direction is enabled. In other words, since the moving pulse signal does not include a noise pulse, the level of the moving pulse signal at which the level of the shaping signal C changes reliably has a stable phase, and the stable level detection of the shaping signal C becomes possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A movement detecting apparatus according to the present invention comprises a displacement detecting means for generating displacement signals of a plurality of phases which smoothly change in response to the movement of a moving body, and a smoothly changing output of the displacement detecting means. Shaping means which changes in response to the signals and produces three-phase digital shaping signals A, B and C having different phases, and a time point when the level of the moving pulse signal changes using the shaping signals A and B for two phases A moving pulse generator for obtaining the moving pulse signal synchronized with the shaping signal A or the shaping signal B; and moving the moving pulse signal in response to the level of the shaping signal C at the time when the level of the moving pulse signal changes. A moving direction creating means for obtaining a direction signal is provided.

The moving pulse creating means inputs a negative AND signal of the shaped signal A and the shaped signal B to a set terminal,
A flip-flop unit configured to input the shaping signal B and a negative AND signal of the shaping signal A to a reset terminal is included, and a moving pulse signal is obtained from an output terminal of the flip-flop unit. it can.

The moving direction creating means may include flip-flop means for outputting a moving direction signal corresponding to the level of the shaping signal C at the time when the level of the moving pulse signal changes.

The moving direction generating means includes a first flip-flop means for outputting a first moving direction signal corresponding to the level of the shaping signal C at the time of one level change of the moving pulse signal, and the other of the moving pulse signals. Second flip-flop means for outputting a second movement direction signal corresponding to the level of the shaping signal C at the time of the level change of
An output generating means for obtaining a moving direction signal in response to the first moving direction signal and the second moving direction signal may be included.

The shaping means has three comparator means having no hysteresis, and the three-phase output signals of the displacement detecting means are shaped by the three comparator means, respectively, to form three-phase shaped signals A, B and C can be created.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show a movement detection device according to an embodiment of the present invention. FIG. 1 shows an overall configuration diagram. The movement detection device of FIG. 1 includes a displacement detector 11 and a shaper 1.
2, a moving pulse generator 13 and a moving direction generator 14.

The displacement detector 11 shown in FIG.
2,23. The detection elements 21, 22, and 23 are supplied with voltages from the DC power supplies 31 and 32 via resistors 33 and 34, and the differential outputs of the elements are three-phase signals corresponding to the displacement of the moving body.

FIG. 2 shows the relationship between the moving body and the detecting element. FIG. 2A shows an example of a rotary moving body. The rotating magnet moving body 24 attached to the rotating shaft is magnetized to four poles, and N poles and S poles are alternately formed at every 90 degrees. The detecting elements 21, 22, and 23 are arranged facing the moving body 24 at a required interval. As the detection element, for example, a magnetoelectric conversion element such as a Hall element, a supersaturated reactor element, or the like is used (here, a Hall element is used). Thereby, in response to the rotational movement of the moving body 24, the detecting elements 21,
At 22 and 23, three-phase smoothly changing displacement signals having different phases are generated. Similarly, FIG. 2B shows an example of a rectilinear moving body, and a rectilinear magnet moving body 25 attached to a rectilinear shaft.
Are magnetized in multiple poles, and N poles and S poles are alternately formed at predetermined intervals. The detection elements 21 and 2 face the moving body 25.
2, 23 are arranged at a required interval. Thereby, in response to the rectilinear movement of the moving body 25, the detection element 2
At 1, 22, and 23, three-phase smoothly changing displacement signals having different phases are generated.

The displacement signal d obtained by the detecting element 21 shown in FIG.
1, d2 are the operational amplifier circuit 35, resistors 36, 37, 3
An output signal a which is differentially amplified by 8, 39 and changes smoothly in response to the moving position is obtained. Similarly, detection element 2
The displacement signals e1 and e2 obtained in the operation amplifier circuit 4
1, an output signal b that is differentially amplified by the resistors 42, 43, 44, and 45 and changes smoothly in response to the moving position is obtained. Similarly, the displacement signals f1,
f2 is an operational amplifier circuit 46, resistors 47, 48, 49, 5
An output signal c that is differentially amplified by 0 and changes smoothly in response to the moving position is obtained. The output signals a, b, and c of the displacement detector 11 become three-phase analog (smoothly changing) output signals having electrically different phases by detecting the moving position of the moving body.

The shaper 12 shown in FIG. 1 has a 3 without hysteresis.
The comparators 61, 62, and 63 output shaping signals A, B, and C obtained by shaping the output signals a, b, and c of the displacement detector 11, respectively.

FIG. 3 shows a specific configuration of the comparator 61. Transistors 102, 103, 104, 105
Compares the analog output signal a with a reference voltage value (here, the ground potential). When the output signal a increases, the transistor 108 is turned on, the transistor 110 is turned off, and the shaped signal A is set to “H” ( (High potential state). Conversely, when the output signal a decreases, the transistor 108 is turned off, the transistor 109 is turned on, and the shaped signal A
To “L” (low potential state). The constant current source 10
1, 109 and 111 supply a predetermined current value. In this way, the comparator 61 without hysteresis compares the analog output signal a of the displacement detector 11 and digitally changes the level of the shaping signal A at the time of the zero crossing of the output signal a. Comparator 62,
The same applies to the output signals b and c.
At the time of zero crossing, the levels of the shaping signals B and C are digitally changed.

The moving pulse generator 13 shown in FIG. 1 receives the two-phase shaped signal A and the shaped signal B,
And the AND circuit 72 produces the negation of the signal B and the AND signal D of the signal A, and inputs the AND signal D to the set terminal of the flip-flop circuit 75 of the set-reset type. The inverter circuit 73 and the AND circuit 74 generate the negation of the signal A and the AND signal E of the signal B, and input them to the reset terminal of the flip-flop circuit 75. as a result,
The output signal of the flip-flop circuit 75 is
Alternatively, a digital moving pulse signal F that changes in synchronization with the shaping signal B is obtained.

The moving direction generator 14 shown in FIG. 1 has a first flip-flop circuit 81 of an edge trigger type and a second flip-flop circuit 82 of an edge trigger type.
The flip-flop circuit 81 detects the rising edge of the moving pulse signal F (at the time when the level changes from “L” to “H”).
Is used as a clock signal, the level of the shaping signal C is latched, and the first moving direction signal G is output. The second flip-flop circuit 82 latches the level of the shaping signal C using the falling edge of the moving pulse signal F (the point of time when the level changes from “H” to “L”) as a clock signal. The second movement direction signal H is output. The AND circuit 85, which is an output creation circuit, outputs the first movement direction signal G
As the moving direction signal J in response to the second moving direction signal H.

Next, the operation of each part of the movement detecting device shown in FIG. 1 will be described in detail with reference to the waveform diagram for explaining the operation shown in FIG. The horizontal axis in FIG. 1 is time, which is in the + moving state up to the left position of the dashed line, and changes from the right position of the dashed line to the -moving state. The output signals a, b, and c of the displacement detector 11 change as three-phase analog signals having electrically different phases [FIGS. 4A, 4B, and 4C].
reference]. The shaper 12 shapes the waveforms of the output signals a, b, and c using comparators 61, 62, and 63, respectively.
Generate phase shaping signals A, B, C. Comparator 61
Has a simple configuration without hysteresis, the time when the edge of the shaping signal A occurs (the time when the level changes) accurately corresponds to the time of the zero crossing of the output signal a.
A large number of fine noise pulses are generated near the edge of the shaping signal A due to the noise mixed into the signal [FIG. 4 (d)]. Similarly, since the comparator 62 also has a simple configuration without hysteresis, the time when the edge of the shaping signal B occurs (the time when the level changes) accurately corresponds to the zero crossing time of the output signal b. A large number of fine noise pulses are generated near the edge of the shaping signal B due to the noise mixed into the signal [FIG. 4 (e)]. Similarly, since the comparator 63 has a simple configuration without hysteresis, the shaped signal C
Corresponds exactly to the zero crossing point of the output signal c, but a number of fine noise pulses are generated near the edge of the shaping signal C due to noise mixed into the output signal c. FIG. 4 (f)].

The moving pulse generator 13 generates an AND signal D [FIG. 4 (g)] and an AND signal E [FIG. 4 (h)] using the shaping signals A and B for two phases. By setting E as a set signal and a reset signal, the flip-flop circuit 75 obtains a moving pulse signal F from which noise pulses have been removed [FIG. 4 (i)]. The moving pulse signal F synchronizes with the shaping signal A at the time of + moving, and a level change of the moving pulse signal F occurs at the time when the level of the shaping signal A changes. That is, the movement pulse signal F at the time of the + movement has a waveform of the same phase from which the noise of the shaping signal A has been removed. As a result, the level change point of the movement pulse signal F at the time of the + movement is
Since this corresponds to the zero crossing point of the output signal a of the displacement detector 11, the cycle and half cycle of the moving pulse signal F are not affected by the amplitude modulation component included in the output signal a. That is, high-accuracy speed measurement becomes possible. Further, since the duty of the moving pulse signal F is 50%, the speed can be measured every half cycle, and the measurement frequency can be increased.

The moving pulse signal F at the time of -movement is synchronized with the shaping signal B, and a level change of the moving pulse signal F occurs at the time when the level of the shaping signal B changes. That is,
-When moving, the moving pulse signal F has an inverted phase waveform from which noise of the shaping signal B has been removed. As a result, the point in time at which the level of the moving pulse signal F changes during the -movement corresponds to the zero crossing point of the output signal b of the displacement detector 11, and the cycle and half cycle of the moving pulse signal F are included in the output signal b. It is no longer affected by the amplitude modulation component. That is, high-precision speed measurement is possible. Further, since the duty of the moving pulse signal F is 50%, the speed can be measured every half cycle, and the frequency of measurement can be increased.

The first flip-flop circuit 81 of the moving direction generator 14 inputs and holds the level of the shaping signal C when the rising edge of the moving pulse signal F occurs,
A first moving direction signal G is obtained [FIG. 4 (j)]. Therefore, the first movement direction signal G becomes "H" during + movement, and the first movement direction signal G changes to "L" at the time when the first rising edge of the movement pulse signal F during-movement occurs.
Similarly, the second flip-flop circuit 82 inputs and holds the level of the shaping signal C when the falling edge of the moving pulse signal F occurs, and obtains the second moving direction signal H via the inverter circuit 84 [FIG. 4 (k)]. Therefore,
The second movement direction signal H becomes "H" during the + movement, and changes to "L" at the time of the first falling edge of the movement pulse signal F during the-movement. The moving direction signal J, which is a combination of the first moving direction signal G and the second moving direction signal H, is "H" during + movement and changes to "L" at the time of the first edge occurrence of the movement pulse signal F during-movement. [FIG. 4 (l)].

If the apparatus is constructed like the movement detection apparatus of the present embodiment, noise at the time of the level change of the movement pulse signal can be easily removed by using the shaped signals for two phases, and the movement pulse signal can be removed. 3 at the time of level change
A moving direction signal corresponding to the level of the phase shaping signal can be easily obtained. In particular, even if the shaping signals A, B, and C include noise at each edge, it is possible to obtain the moving pulse signal F and the moving direction signal J from which those noises are clearly removed.

Further, the moving pulse generator inputs a negative AND signal of the shaped signal A and the shaped signal B to a set terminal,
It is configured to include a flip-flop circuit in which a shaped signal B and a negative AND signal of the shaped signal A are input to a reset terminal, and a moving pulse signal F is obtained from an output terminal of the flip-flop circuit. With the configuration, a moving pulse signal without noise can be easily generated. At this time, if the waveform of the output signal of the displacement detector is shaped by a comparator having no hysteresis to obtain a shaped signal A and a shaped signal B, a comparator having a very simple configuration can be used, and the displacement detector can be used. Even if amplitude modulation components occur in the output signals a and b, the influence thereof can be eliminated in principle, and the period of the moving pulse signal is not disturbed. Further, since the duty of the moving pulse signal F is 50%, the speed can be measured every half cycle.

The moving direction generator has an edge-triggered flip-flop circuit for inputting the level of the shaping signal C at the time when the level of the moving pulse signal changes, and outputs the moving direction signal from the output terminal of the flip-flop circuit. Therefore, there is no noise pulse at the time when the level of the moving pulse signal changes, and the level of the shaping signal C is completely determined at the time when the level of the moving pulse signal changes (the effect of noise occurs). In this case, a reliable direction detection is possible with a simple circuit configuration. At this time, a sufficiently large phase difference can be obtained between the time when the level of the moving pulse signal changes and the time when the level of the shaping signal C changes, so that the noise margin also increases. Note that the noise margin depends on the amplitude of the displacement signal, and a very large noise margin can be secured by increasing the amplitude of the displacement signal.

The moving direction creator includes a first flip-flop circuit for outputting a first moving direction signal corresponding to the level of the shaping signal C at one level change point (rising edge) of the moving pulse signal; A second flip-flop circuit for outputting a second moving direction signal corresponding to the level of the shaping signal C at the other level change point (falling edge) of the pulse signal; It is configured to include an output creation circuit for obtaining a moved direction signal J in response. This makes it possible to detect the moving direction signal each time a level change of the moving pulse signal occurs, thereby enabling quick and reliable direction detection.

Further, the shaper converts the three-phase output signals of the displacement detector which are electrically different in phase from each other into a signal having no hysteresis.
Waveforms are shaped by three comparators, and three-phase shaped signals A,
B and C are created. Even if such a very simple comparator is used, it is possible to reliably detect a moving pulse signal and a moving direction signal without noise pulses.

The specific configuration of the above-described embodiment can be modified in various ways. For example, an optical photocoupler or the like may be used as a detection element of the displacement detector. It is not necessary to use three detection elements. For example, a three-phase output signal may be generated by combining the outputs of the two detection elements. Further, the phase difference between the three-phase digital shaping signals is not limited to 120 degrees, but can be configured as long as the mutual phase difference is at least about 30 degrees. The moving direction generator does not need to use both edges of the moving pulse signal, and may detect the level of the shaping signal C at one edge. Also, the comparator may be provided with hysteresis.

In addition, various modifications can be made without changing the gist of the present invention, and it goes without saying that the present invention is included in the present invention.

[0036]

As described above, with the structure of the movement detecting device of the present invention, it is possible to obtain a highly accurate moving pulse signal and a moving direction signal without the influence of noise included in the displacement signal. Therefore, the malfunction of the measurement of the moving speed and the measurement of the moving direction is eliminated, and extremely stable movement detection becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing an overall configuration according to an embodiment of the present invention.

FIGS. 2A and 2B are diagrams illustrating a structure used for a displacement detector 11 according to the embodiment. FIG. 2A is a diagram illustrating an example of a rotary moving body. FIG.

FIG. 3 is a specific circuit diagram of a comparator 61 according to the embodiment;

FIGS. 4A to 4L are diagrams showing waveforms of respective signals in the embodiment.

FIG. 5 is a diagram showing a configuration of a conventional detection device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Displacement detector 12 Shaper 13 Moving pulse generator 14 Moving direction generator 24, 25 Moving body 21, 22, 23 Detection element 61, 62, 63 Comparator 75, 81, 82 Flip-flop circuit

Claims (5)

[Claims] 1. A displacement detecting means for generating a plurality of phase displacement signals which smoothly change in response to the movement of a moving body, and a phase change means which changes in response to a smoothly changing output signal of said displacement detecting means. Three different digital shaped signals A,
The shaping means for generating B and C and the shaping signal A and B for two phases are used to remove noise at the time of the level change of the moving pulse signal, and the movement synchronized with the shaping signal A or the shaping signal B is performed. A movement detection apparatus comprising: a movement pulse creation means for obtaining a pulse signal; and a movement direction creation means for obtaining a movement direction signal corresponding to the level of the shaping signal C at the time when the level of the movement pulse signal changes. 2. The moving pulse generator inputs a shaped signal A and a NOT signal of the shaped signal B to a set terminal, and inputs the shaped signal B and a NOT signal of the shaped signal A to a reset terminal. 2. The movement detection device according to claim 1, wherein the movement detection device is configured to include a flip-flop means and obtains a movement pulse signal from an output terminal of the flip-flop means. 3. The moving direction generating means according to claim 1, wherein said moving direction generating means includes flip-flop means for outputting a moving direction signal corresponding to the level of the shaping signal C at the time when the level of the moving pulse signal changes. Movement detection device. 4. The moving direction generating means includes: first flip-flop means for outputting a first moving direction signal corresponding to the level of the shaping signal C at the time of one level change of the moving pulse signal; Second flip-flop means for outputting a second moving direction signal responsive to the level of the shaping signal C at the time of the other level change; a moving direction signal responsive to the first moving direction signal and the second moving direction signal The movement detecting device according to claim 1, further comprising an output creating unit that obtains the following. 5. The shaping means has three comparators having no hysteresis, and the three-phase output signals of the displacement detecting means are shaped by the three comparators, respectively, to form a three-phase shaped signal A. , B, and C were created.
The movement detection device according to any one of claims 1 to 4.