JPH0476048B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention detects the total rotational speed and rotation angle within 360° of an electric motor, for example in a so-called electric robot whose working end is driven by a drive source. The present invention relates to an encoder device suitably implemented for the purpose of the present invention.

BACKGROUND ART In typical existing technology, the power from the rotating shaft of a motor is reduced by a speed reducer and transmitted to the working end, and the output shaft of the motor is connected to the working end in order to detect the rotation angle of the working end. Another detecting reducer having the same reduction ratio as that of the detecting reducer is provided, and the rotation angle of the reduction output shaft of the detecting reducer is detected by a potentiometer. On the other hand, the output shaft of the motor is equipped with a so-called incremental encoder, making it possible to detect the rotation angle of the output shaft within 360° with high precision. There is.

Problems to be Solved by the Invention With the existing technology as described above, there was a problem in that a decelerator for detection was required, the encoder device became large, and the backlash of the decelerator for detection caused measurement errors. . In addition, the incremental encoder has a structure in which a light emitting element and a light receiving element are installed on both sides of a rotating member attached to a rotating shaft to detect a transparent part or a light blocking part formed on the rotating member. If such an incremental encoder were to be operated by a battery, the power consumption of the incremental encoder would be large, so the capacity of the battery would have to be large, and the power supply associated with the encoder would have to be large.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an encoder device that can detect a rotation angle with high precision without increasing the size of the entire device.

Another object of the present invention is to provide an encoder device that can detect with high precision the rotation angle of a rotating shaft that has undergone angular displacement during a power outage period when the power is restored.

Means for Solving the Problems The present invention provides: a rotating disk member 8 attached to a rotating shaft 2 and having transparent hole portions 14, 15 and light shielding portions alternately and repeatedly formed over the entire circumference; and the rotating disk member 8. a light emitting element 9 which is disposed at a fixed position on one side in the axial direction of the rotating shaft 2 with respect to the plate member 8 and emits light toward the through hole portions 14 and 15 and the light shielding portion; and a rotating shaft with respect to the rotating disk member. light-receiving elements 10 and 11 which are arranged at a fixed position on the other side in the axial direction and receive light from the light-emitting element 9 through the through-hole portions 14 and 15; A rotation angle detection means 18 for detecting the rotation angle of the rotation shaft; a permanent magnet piece 21 fixed to the rotation shaft 2 via a member 20 made of a non-magnetic material; and a permanent magnet piece 21 provided at a fixed position. The magnetic detection elements 22 and 23 detect the magnetic field of the magnetic detection elements 22 and 23, the counting circuit 29 counts and stores the output of the magnetic detection elements 22 and 23, and the light emitting element 9, the light receiving elements 10 and 11, and the rotation angle detection means 18 are powered power supply circuits 31, 32
And, even when the power supply circuits 31 and 32 are out of power,
battery means 3 for energizing the counting circuit 29;
This is an encoder device composed of 0 and 0.

The present invention also provides a rotating disk member 8 which is attached to the rotating shaft 2 and in which transparent hole portions 14, 15 and light shielding portions are alternately and repeatedly formed over the entire circumference; a light emitting element 9 which is disposed at a fixed position on one side in the axial direction of the rotary disk member and emits light toward the transparent hole portions 14, 15 and the light shielding portion; light-receiving elements 10 and 11 that are arranged at fixed positions and receive light from the light-emitting element 9 through the through-hole portions 14 and 15; A rotation angle detection means 18 for detecting the angle; a protrusion fixed to the rotating shaft 2 via a member 20; a microswitch provided at a fixed position and having an actuator in contact with the protrusion; and a microswitch for counting the output of the microswitch. A counting circuit 29 for storing information, and power supply circuits 31 and 32 for energizing the light emitting element 9, the light receiving elements 10 and 11, and the rotation angle detection means 18.
And, even when the power supply circuits 31 and 32 are out of power,
battery means 3 for energizing the counting circuit 29;
An encoder device configured by 0 and 0.

Effects According to the present invention, the rotation angle of the rotating shaft can be detected with high precision without requiring a detection reducer and therefore without increasing the size of the encoder device.

Further, according to the present invention, the counting circuit 29 is always operated by the battery means 30, so that the power supply circuit 3
The light emitting element 9, the light receiving elements 10, 11, and the rotation angle detecting means 18 are powered even in the event of a power outage. As a result, the number of rotations of the rotating shaft 2 can always be detected even during a power outage of the power supply circuits 31 and 32 without increasing the size of the battery means 30.

Embodiment FIG. 1 is a block diagram of an electric robot equipped with an encoder device according to the present invention. In this electric robot, the rotating shaft 2 of the motor 1 has gears 4a and 4b.
The working end 6 is rotationally driven from the output shaft 5. The rotary shaft 2 of the motor 1 is provided with an incremental encoder 7 serving as rotation angle detection means.

FIG. 2 is a perspective view showing the principle of the incremental encoder 7. The incremental encoder 7 includes a rotating disk member 8 mounted on the rotating shaft 2,
A light emitting element 9 is provided on one side in the axial direction of the rotating shaft 2 with respect to the rotating disc member 8 (left side in FIG. 2), and a light emitting element 9 is provided on the other side in the axial direction of the rotating shaft 2 with respect to the rotating disc member 8 2) on the right side of FIG. 2). The rotating disk member 8 is made of a light-shielding member such as metal, and has a first track 12 and a second track 13 that are arranged radially offset. The first track 12 has detection holes 14 formed at equal intervals over the entire circumference of the rotating disk member 8. The second track 13 also has detection holes 15 formed at equal intervals over the entire circumference of the rotating disk member 8. The detection through-hole 14 of the first track 12 and the detection through-hole 15 of the second track 13 are out of phase by 90 degrees in electrical angle in the circumferential direction of the rotating disk member 8.

The light passing from the light emitting element 9 through the detection hole 14 is
It is detected by the light receiving element 10. Light passing from the light emitting element 9 through the detection through hole 15 is detected by the light receiving element 11. Referring also to FIG. 1, the outputs from the light receiving elements 10 and 11 are input to the rotational direction discrimination circuit 16 via lines 11 and 12. The signal waveforms derived from the light receiving elements 10 and 11 to the lines l1 and l2 are as shown in FIG. 3(1) and FIG. 3(2), respectively, during the rotation of the rotating disk member 8. As described above, these detection outputs have a phase difference of 90° in electrical angle. The rotational direction discrimination circuit 16 is configured such that the rotating disk member 8 is
When rotating in the direction (see FIG. 2), a pulse shown in FIG. 3 (3) corresponding to the output from the light receiving elements 10 and 11 is derived to line l3. line l4
The output becomes high level when the rotating disk member 8 rotates in the direction of the arrow 17, and at this time, the output of the line l5
The output of is low level. When the rotating disk member 8 rotates in the direction opposite to the direction of the arrow 17, the output on line l4 is at a low level, and the output on line l5 is at a high level. Updown counter 1
8 adds the pulses shown in FIG. 3(3) via line l3 to count up when line l4 is at high level, and subtracts and counts down when line l5 is at high level.

The output of the up-down counter 18 is on line l6.
When the line l4 is at high level, the output shown in FIG. 3(4) is derived. The up-down counter 18 is connected to the rotating disk member 8 with respect to the rotating shaft 2.
The count value detected from line 16 is reset every time the motor rotates once. In this way, the rotation angle of the rotation shaft 2 within 360° can be detected with high precision using the rotation angle signal representing the rotation angle of the rotation shaft 2 from the line 16. Updown counter 1
8 is reset by a reset signal from line l ¹ 4 so that the count value becomes zero. Rotating axis 2
A rotation speed detection means 19 is provided in connection with the rotation speed detection means 19. FIG. 4 is a perspective view of the rotation speed detection means 19, and the fifth
The figure is a side view thereof. The rotation speed detection means 19 is
It has a rotating disk member 20 fixed to a rotating shaft 2. The rotating disk member 20 is made of a non-magnetic material such as metal or synthetic resin. A permanent magnet piece 21 is attached to one surface of the rotating disk member 20. Due to the magnetic field of the permanent magnet piece 21, the rotating disk member 20
The switching mode of reed switches 22 and 23 arranged at intervals in the circumferential direction changes.
The reed switch 22 has a pair of electrodes 25, 2 provided in a space inside a sealing body 24 made of glass or the like.
6, and the switching mode of the electrodes 25 and 26 changes depending on the magnetic field of the permanent magnet piece 21. Reed switch 23 has a similar configuration to reed switch 22. By changing the switching mode of the reed switches 22 and 23, electric signals having a phase difference in the circumferential direction of the rotating disk member 20 are generated as shown in FIG. 3(1) and with extremely small power consumption. Figure 3(2)
are derived as shown in respectively.

When the rotating shaft 2 rotates in the direction of the arrow 17, the reed switches 22 and 23 output the signals shown in FIG.
The signals shown in FIG. 6 are applied to the rotational direction discrimination circuit 28 via lines 17 and 18, respectively. The rotational direction discrimination circuit 28 includes reed switches 22, 2
When the rotary disk member 20 rotates in the direction of arrow 17 based on the phase difference from 3, a high level signal is derived on line l10, and at this time, line l11 is at low level. The rotation direction discrimination circuit 28 derives a low level signal to the line l10 when the rotating disk member 20 rotates in the opposite direction of the arrow 17.
A high level signal is derived to line l11. The rotational direction discrimination circuit 28 derives a signal having the waveform shown in FIG. 3(7) based on the outputs from the reed switches 22 and 23 on the line 19. The signal from line 19 is also provided as a reset signal to up-down counter 18 via line 114.
Signals from lines 19-111 are received by up-down counter 29. This up-down counter 29 counts up by adding up the pulses on line 19 when the signal from line 110 is at high level, and counts down by subtracting the pulses on line 19 when line 111 is at high level.

Lines l7, l from reed switches 22, 23
The pulses obtained via line 19 and the pulses obtained from line 19 are transmitted to the rotating shaft 2 and the rotating disk member 2.
Therefore, the count value of the up-down counter 29 represents the number of rotations of the rotating shaft 2, and the rotating shaft 2 and the rotating disk member 20 are
When the up-down counter 29 rotates in the direction 7, the count signal derived to the line 112 of the up-down counter 29 has a waveform shown in FIG. 3(8).

The rotational direction discrimination circuit 28 and the up-down counter 29 are realized by semiconductor circuits, and therefore consume little power. The rotation direction discrimination circuit 28 and the up/down counter 29
Powered by.

The rotational direction discrimination circuit 16, the up/down counter 18, and the light emitting element 9 and the light receiving elements 10, 11 of the incremental encoder 7 are energized by the power of a power supply circuit 32 that transforms and rectifies the power from a commercial AC power supply 31. . The rotation direction discrimination circuit 16 and the up-down counter 18 can be realized by semiconductor circuits. Light emitting element 9
is constantly energized to emit light when detecting the rotation angle, and is realized by, for example, a light emitting diode, and its power consumption is relatively large.

The rotation angle signal shown in FIG. 3 (4) is derived from the up-down counter 18 to line l6, and the rotation speed signal shown in FIG. 3 (8) is derived from the up-down counter 29 through line l12. is applied to the arithmetic circuit 33, whereby a signal shown in FIG. 3(9) representing the total rotation angle of the rotary shaft 2 is derived from the line l13. When the commercial AC power supply 31 is out of power, the rotation direction discrimination circuit 16 and the up/down counter 18 are disabled, and the light emitting element 9 stops emitting light. Rotation direction discrimination circuit 2
8 and up/down counter 29 remain energized by battery 30 even during a power outage. Therefore, when the rotation speed detection means 19 is angularly displaced and the switching mode of the reed switches 22 and 23 changes due to the magnetic field of the permanent magnet piece 21, the rotation direction is discriminated by the rotation direction discrimination circuit 28. The count value of the up-down counter 29 is changed and stored. Therefore, even if the motor 1 is deenergized due to a power outage of the commercial AC power supply 31 and the working end 6 is angularly displaced due to its gravity etc., and the rotating shaft 2 is accordingly angularly displaced, the rotation speed detection means 19, the rotational speed of the rotating shaft 2 is constantly detected by the functions of the rotational direction discrimination circuit 28 and the up-down counter 29.

After power is restored, motor 1 and rotation speed discrimination circuit 16
and the up/down counter 18 is connected to the power supply circuit 32.
energized by power from the The arithmetic circuit 33 is also energized. When the rotary shaft 2 is rotationally driven by the motor 1 and the pulses shown in FIG. 3 (5) and FIG. 3 (6) are obtained from the reed switches 22 and 23, the count value of the up-down counter 18 is By resetting to zero as shown in FIG. 3(4), the subsequent rotation angle of the rotating shaft 2 within 360° can be measured with high precision.

In the above embodiment, the permanent magnet piece 21 is fixed to the rotating shaft 2 via the member 20 made of a non-magnetic material, and the permanent magnet piece 21 is not configured to be attached to the rotating disk member 8. . By attaching the permanent magnet piece 21 to the member 20 provided separately from the member 8 in this way, both the members 8, 20
can be made smaller. If the permanent magnet pieces 21 were to be attached radially outward or radially inward of the tracks 12, 13 of the member 8, the outer diameter of the member 8 would have to be increased. As a result, it becomes impossible to incorporate it into the robot's arm. In order to solve this problem, if a small permanent magnet piece is attached to the member 8, the positional accuracy of the reed switches 22 and 23 that detect such a small permanent magnet piece 21 must be increased, Also, such a small permanent magnet piece 21 and reed switches 22, 23
The gap between the two must be set precisely, and furthermore, there is a risk that erroneous detection may occur due to slight center runout of the rotating shaft 2. In the embodiment described above, by attaching the permanent magnet piece 21 to the member 20 provided separately from the member 8 on which the tracks 12 and 13 are formed, the overall structure can be made smaller. There is no need to unnecessarily reduce the size of the permanent magnet piece 21, there is no need to increase assembly precision, and there is no possibility of erroneous detection due to center runout of the rotating shaft 2.

In the embodiment described above, the reed switches 22 and 23 do not consume power, and the power of the battery 30 is supplied to the rotation direction discrimination circuit 28 and the up/down counter 29, which circuits 28 and 29 are implemented by, for example, integrated circuits. The power consumption is negligible. In place of the reed switches 22, 23, for example, a magnetoresistive element may be used, and the resistance of such a magnetoresistive element is, for example, 600 kΩ, it operates at 3.6V, and its power consumption is therefore extremely low. . According to experiments by the inventor of the present invention, using such a magnetic resistance element, the rotation direction discrimination circuit 28 and the up/down counter 29
When constructed using an integrated circuit, the life of the batteries 30 was 4 years when two batteries 30 with a capacity of 2 Ah were used in parallel. On the other hand, the permanent magnet piece 21 and the reed switches 22, 23
When configured using a light emitting diode and a light receiving element instead, the light emitting element has a current of 10 mA, for example.
The output of the light-receiving element is given to the rotational direction discrimination circuit 28, and the rotational direction discrimination circuit 28 and the up-down counter 29 are connected to two batteries 30 with a capacity of 2Ah together with a light emitting diode. When used to constantly supply power, the battery 30 had a lifespan of only about 400 hours. Therefore, as in the above-described embodiment, the commercial AC power source 31 can be connected to the commercial AC power source 31 by using the permanent magnet piece 21 and the reed switches 22, 23, or by using a magnetic resistance element or the like in place of the reed switches 22, 23. The battery described above can be used not only for short-term power outages, but also for long-term power outages, and even when the encoder device is shipped from the factory with the power turned off.

If the above-mentioned light emitting diode is used in place of the permanent magnet piece 21, it would be possible to perform sampling by lighting the light emitting diode intermittently in order to reduce power consumption. In practice, the cycle duty seems to be limited to about 1:10 (ie, 1/10), and therefore, effects as excellent as those of the above-mentioned embodiments cannot be expected.

As yet another embodiment of the present invention, in place of the above-mentioned reed switches 22 and 23, a rotary disk member 2
A means for generating an induced electromotive force by a change in the magnetic field of the permanent magnet piece 21 attached to the permanent magnet piece 21 may be used. Such an induced electromotive force generating means does not consume any power and is convenient. As such an induced electromotive force generating means, for example, a rod-shaped ferromagnetic material whose magnetization strength changes suddenly depending on the increase or decrease of the external magnetic field as the permanent magnet piece 21 approaches, and a rod-shaped ferromagnetic material that is It has a configuration in which it includes a wound detection coil and generates an impulse-like induced electromotive force by a sudden change in the strength of the magnetization.

According to the present invention, magnetic sensing elements having other configurations may be used.

As another embodiment, instead of the combination of the permanent magnet piece 21 and the reed switches 22 and 23, the rotary shaft 2
A microswitch is provided at a fixed position with a protrusion formed on a member 20 fixed to the member 20 and an actuator in contact with the protrusion, and the actuator is moved along the movement path of the protrusion according to the rotation of the rotation axis 2 and thus the member 20. They may be arranged at intervals in the circumferential direction. The remaining configuration is similar to the previous embodiment.

Effects As described above, according to the present invention, a rotation angle can be detected with high accuracy without increasing the size of the configuration. In particular, according to the first invention described in claim 1, a permanent magnet piece 21 is fixed to the rotating shaft 2 via a member 20 made of a non-magnetic material. A counting circuit 29 is provided, which detects the magnetic field by magnetic detection elements 22 and 23 provided at fixed positions, and counts and stores the outputs of the magnetic detection elements 22 and 23. Since the light emitting element 9 and the light receiving elements 10 and 11 are always energized by the
Even if a power outage occurs in the power supply circuits 31 and 32 that energize the rotation angle detection means 18 and the rotation angle detection means 18, detection of the rotation speed can be reliably achieved. Moreover, such a counting circuit 29
The power consumption of the battery means 30 can be reduced and the life of the battery means 30 can be extended.

Further, according to the first invention, the permanent magnet piece 21 is
It is fixed to the rotating shaft 2 via a member 20 provided separately from the rotating disk member 8. Therefore, if it were assumed that the permanent magnet piece 21 was attached to the rotating disk member, According to the present invention, the problem that the rotating disk member 8 becomes large does not occur, and according to the present invention, the entire configuration can be downsized. Moreover, it is not necessary to configure the permanent magnet piece 21 minutely, so that the magnetic detection element 2
2 and 23 is not required, and there is no need to make the gap between the permanent magnet piece 21 and the magnetic detection elements 22 and 23 excessively precise. Also, erroneous detection by the magnetic detection elements 22 and 23 can be prevented.

Further, in the first invention, as described above, the permanent magnet piece 21
Since the magnetic field of the permanent magnet piece 21 is detected by the magnetic detection elements 22 and 23, there is no power consumption of the permanent magnet piece 21, and the power consumption of the magnetic detection elements 22 and 23 is zero. The counting circuit 29 that receives the outputs of the magnetic detection elements 22 and 23 is realized by an integrated circuit, for example, and the power consumption of the counting circuit 29 can be made small. As a result, the life of the battery means 30 can be made extremely long, for example, 4 years.

Further, according to the second invention described in claim 2, a protrusion is fixed to the rotating shaft 2 via the member 20, and a micro switch having an actuator that contacts the protrusion is provided at the fixed position. The output of the microswitch is counted and stored by the counting circuit 29, and the counting circuit 29 is always energized by the battery means 30 even during a power outage of the power supply circuits 31 and 32. Also, the battery means 30 has a long life,
Enables constant rotation speed detection. That is, according to the configuration having such a protrusion and a microswitch, there is no power consumption by the microswitch, and the counting circuit 29 that receives the output of the microswitch can be realized by, for example, an integrated circuit. As a result, the life of the battery means 30 can be sufficiently extended to, for example, about four years as described above. Moreover, the protrusion is member 2
Since it is fixed to the rotating shaft 2 through the actuator, it can be made smaller as in the first invention, and there is no need to make the protrusions minute, so the position accuracy of the micro switch with the actuator can be improved. This is not required, and furthermore, even if the rotating shaft 2 runs out, erroneous detection by the microswitch can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG.
The figure is a perspective view of the incremental encoder.
The figures are waveform diagrams for explaining the operation of the embodiment shown in FIG. 1, FIG. 4 is a perspective view of the rotation speed detection means 19, FIG. 5 is a side view of the rotation speed detection means 19, and FIG. FIG. 3 is a perspective view of another embodiment of an incremental encoder. 2... Rotation axis, 7... Incremental encoder, 9... Light emitting element, 10, 11... Light receiving element, 16, 28... Rotation direction discrimination circuit, 18, 2
9...Up-down counter, 30...Battery.

Claims (1)

[Scope of Claims] 1. A rotating disk member 8 attached to the rotating shaft 2 and having transparent hole portions 14, 15 and light blocking portions alternately and repeatedly formed over the entire circumference; and the above-mentioned regarding the rotating disk member 8. a light emitting element 9 which is disposed at a fixed position on one side in the axial direction of the rotating shaft 2 and emits light toward the through-hole portions 14 and 15 and the light shielding portion; Light-receiving elements 10 and 11 are arranged at fixed positions on the other side and receive light from the light-emitting element 9 through the through-hole parts 14 and 15, and the outputs of the light-receiving elements 10 and 11 are counted, and the rotation axis a permanent magnet piece 21 fixed to the rotating shaft 2 via a member 20 made of a non-magnetic material; and a permanent magnet piece 21 that is provided at a fixed position and detects the magnetic field of the permanent magnet piece 21. a counting circuit 29 that counts and stores the outputs of the magnetic detection elements 22 and 23; and a power supply circuit that energizes the light emitting element 9, the light receiving elements 10 and 11, and the rotation angle detection means 18. 31, 32
And, even when the power supply circuits 31 and 32 are out of power,
battery means 3 for energizing the counting circuit 29;
An encoder device configured by 0 and 0. 2. A rotating disk member 8 attached to the rotating shaft 2 and having transparent hole portions 14, 15 and light shielding portions alternately and repeatedly formed over the entire circumference; A light emitting element 9 is disposed at a fixed position on one side of the rotary disk member and emits light toward the transparent hole portions 14 and 15 and the light shielding portion; The light receiving elements 10 and 11 are arranged to receive light from the light emitting element 9 through the through-hole portions 14 and 15, and the outputs of the light receiving elements 10 and 11 are counted, thereby detecting the rotation angle of the rotating shaft. A rotation angle detection means 18, a protrusion fixed to the rotating shaft 2 via a member 20, a microswitch provided at a fixed position and having an actuator that contacts the protrusion, and a counting circuit that counts and stores the output of the microswitch. 29, and power supply circuits 31 and 32 that energize the light emitting element 9, the light receiving elements 10 and 11, and the rotation angle detection means 18.
And, even when the power supply circuits 31 and 32 are out of power,
battery means 3 for energizing the counting circuit 29;
An encoder device configured by 0 and 0.