JPH06214651A - Optical rotary encoder - Google Patents

Abstract

PURPOSE:To perform positioning control with high reliability by solving a problem that the driving noise of a motor or the like is propagated to a signal cable by electromagnetic induction and the positioning control itself is adversely affected in an optical rotary encoder for detecting a speed and a position connected to the motor applied to an industrial equipment or the like. CONSTITUTION:In the Figure 1, by the rotation of a circular light shielding plate 2 fixed to a shaft 1 directly connected to the motor, light projected from a light emitting element 3 is inputted through a slit plate 4 and the circular light shielding plate 2 to a light receiving port 5 as pulse signals. The pulse signals are outputted to an outside by a composite cable (the composite cable of an electric cable and a light transmission cable) 6. By this constitution, even in the case of wiring in which the composite cable 6 and a motor cable are adjacent, the electromagnetic induction intrinsic to the electric cable is not induced, the noise is not interposed on the above-mentioned pulse signals and the positioning control with the high reliability can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is an optical rotary encoder for position / speed detection connected to a motor, which is applied to industrial equipment, machine tools, electrical equipment and the like.

[0002]

2. Description of the Related Art Generally, an optical rotary encoder is often used for position detection and speed detection of a DC or AC motor rotating at high speed. The conventional optical rotary encoder will be described below.

FIG. 7 is an example of a cross section of a conventional optical rotary encoder. When a circular light shielding plate 102 directly connected and fixed to a motor shaft 101 is rotated, light emitted from a light emitting element 103 is circular with a slit plate 104. Shading plate 102
To reach the light receiving element 107 via.

The motor shaft 101 and the circular shading plate 1
02, the light emitting element 103, the slit plate 104, and the light receiving element 107 are three-dimensionally shown in FIG. 9, and the light reaching the light receiving element 107 due to the rotation of the circular light shielding plate 102 is incident and blocked. Becomes a pulse signal that is continuously repeated.

The pulse signal is converted into an electric signal and output to the outside by the signal cable 114 shown in FIG. As an example, the feedback system shown in FIG. 8 is configured.

In the operation of the feedback system, the position command 131 from the numerical controller 151 and the position feedback signal 132a from the optical rotary encoder 142 are compared by the position feedback comparison unit 122a, and the position gain unit 123a performs the speed command. 133a and outputs the speed command 133a and the optical rotary encoder 142.
The speed feedback signal comparing unit 122b performs the comparison with the speed feedback signal 132b, and the speed gain unit 123b outputs the current command 133b. Current command 1
33b, the motor drive unit 121 causes the motor 141
And a pulse signal is generated from the optical rotary encoder 142 by the rotation of the motor 141. The pulse signal is converted into a position feedback signal 132a and a velocity feedback signal 132b by the digital / analog converter 126.

[0007]

However, in the above configuration, the motor drive unit 121, the position feedback comparison unit 122a, the speed feedback comparison unit 122b, the position gain unit 123a, the speed gain unit 123b, and the optical rotary encoder are used. Since the power supply unit 124 and the digital / analog converter 126 are built in the positioning control device 152, and the motor 141 and the optical rotary encoder 142 are integrated as the servo motor 153,
In many cases, the signal cable 114 and the motor cable 127 are arranged close to each other. Therefore, there is a problem that noise generated mainly due to the drive unit 121 that performs high-speed switching propagates to the signal cable 114 by electromagnetic induction and often adversely affects the positioning control itself.

The present invention provides an optical rotary encoder for highly reliable positioning control that solves the above-mentioned conventional problems.

[0009]

In order to solve the above-mentioned problems, the optical rotary encoder of the present invention uses an optical rotary encoder 142 in which the rotational speed and the rotational direction of the optically detected motor 141 are detected from inside the optical rotary encoder 142. It is characterized in that it is transmitted from the optical rotary encoder to the positioning control device 152 by transmission or space transmission.

[0010]

According to the above transmission method, the electromagnetic induction peculiar to the electric wire is not induced in the signal cable 114. Since the output signal of the optical rotary encoder transmitted without induction of electromagnetic induction is converted into the position feedback signal 132a and the velocity feedback signal 132b in the positioning control device 152, highly reliable positioning control without noise is performed. be able to.

[0011]

【Example】

(Embodiment 1) An optical rotary encoder according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of an optical rotary encoder according to a first embodiment of the present invention. 1 is a motor shaft, 2 is a circular light shield plate, 3 is a light emitting element, 4 is a slit plate, 5 is a light receiving port. , 6 is a composite cable of an optical transmission cable and an electric wire.

The operation inside the optical rotary encoder will be described below. The light emitted from the light emitting element 3 is input to the light receiving port 5 as a pulse signal through the slit plate 4 and the circular light shielding plate 2 by the rotation of the circular light shielding plate 2 directly connected and fixed to the motor shaft 1. The pulse signal is output to the outside by the optical rotary encoder cable 6. As an example, the feedback system shown in FIG. 2 is constructed.

FIG. 2 shows a feedback system according to the first embodiment of the present invention. 6 is a composite cable of an optical transmission cable and a power supply wire, 21 is a motor drive unit, 22a is a position feedback comparison unit, 22b is a speed feedback comparison unit, 23a is a position gain unit, 23b is a speed gain unit, and 24 is optical. Type rotary encoder power supply unit, 25 an optical inverse converter, 26 a digital / analog converter, 27
Is a motor cable, 31 is a position command, 32a is a position feedback signal, 32b is a speed feedback signal, 3
3a is a speed command, 33b is a current command, 41 is a motor, 4
2 is an optical rotary encoder, 51 is a numerical controller,
52 is a positioning control device and 53 is a servo motor.

The operation of the feedback system will be described below. Position command 31 from the numerical controller 51 and position feedback signal 32 from the optical rotary encoder 42.
The position feedback comparison unit 22a performs comparison with a,
The position gain section 23a outputs the speed command 33a, the speed feedback comparison section 22b compares the speed command 33a with the speed feedback signal 32b from the optical rotary encoder 42, and the speed gain section 23b outputs the current command 33b. To do. The motor driving unit 21 drives the motor 41 based on the current command 33b, and the pulse signal from the optical rotary encoder 42 generated by the rotation of the motor 41 is converted into a position feedback signal by the optical inverse converter 25 and the digital / analog converter 26. 32a and velocity feedback signal 32b.

As described above, according to this embodiment, the pulse signal output from the light receiving portion of the optical rotary encoder 42 is output as the pulse signal of the optical rotary encoder 42 by the optical transmission cable, and the composite cable 6 and Even when the wiring is close to the motor cable 27, electromagnetic induction peculiar to the electric wire is not induced, and highly reliable positioning control without intervening noise can be performed.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 3 is a sectional view of an optical rotary encoder according to a second embodiment of the present invention. In FIG. 3, 1 is a motor shaft, 2 is a circular light shield plate, 3 is a light emitting element, 4 is a slit plate, and 7 is a slit plate. Is a light receiving element, 8 is a transmitter, and 9 is an optical rotary encoder power cable.

The operation inside the optical rotary encoder will be described below. The light projected from the light emitting element 3 is input to the light receiving element 7 as a pulse signal through the slit plate 4 and the circular light blocking plate 2 by the rotation of the circular light blocking plate 2 directly connected and fixed to the motor shaft 1. The pulse signal is spatially transmitted as an electromagnetic wave to the outside by the transmitter 8. As an example, the feedback system shown in FIG. 4 is constructed.

FIG. 4 shows a feedback system according to the second embodiment of the present invention. 9 is an optical rotary encoder power cable, 21 is a motor drive unit, 22a is a position feedback comparison unit, 22b is a speed feedback comparison unit,
23a is a position gain section, 23b is a speed gain section, 24 is an optical rotary encoder power supply section, 25 is an optical inverse converter, 26 is a digital / analog converter, 27 is a motor cable, 28 is a receiver, and 31 is a position. Command, 32a is a position feedback signal, 32b is a speed feedback signal, 33a is a speed command, 33b is a current command, 41 is a motor, 43 is an optical rotary encoder, 51 is a numerical controller, 54 is a positioning controller, and 55 is a servo. It is a motor.

The operation of the feedback system will be described below. A position command 31 from the numerical controller 51 and a position feedback signal 32 from the optical rotary encoder 43.
The position feedback comparison unit 22a performs comparison with a,
The position gain unit 23a outputs the speed command 33a, and the speed command 33a is compared with the speed feedback signal 32b from the optical rotary encoder 43 by the speed feedback comparison unit 22b, and the speed gain unit 23b outputs the current command 33b. To do. The motor drive unit 21 drives the motor 41 based on the current command 33b, and the rotation of the motor 41 causes the pulse signal from the optical rotary encoder 43 to be received by the receiver 28 and the digital / analog converter 26 and the position feedback signal 32a and the speed feedback signal. Signal 32b.

As described above, according to this embodiment, the oscillator 8 for signal transmission is arranged in the light receiving portion of the optical rotary encoder 43 to transmit the pulse signal of the optical rotary encoder 43 by spatial transmission. As a result, the pulse signal of the optical rotary encoder 43 does not have to be transmitted by the electric wire, so that electromagnetic induction peculiar to the electric wire is not induced, and highly reliable positioning control without noise can be performed. .

(Embodiment 3) A third embodiment of the present invention will be described below with reference to the drawings.

FIG. 5 is a sectional view of an optical rotary encoder according to a third embodiment of the present invention, in which 1 is a motor shaft, 2 is a circular light shielding plate, 4 is a slit plate, 5 is a light receiving port,
10 is the end of the optical transmission cable, 11a, 11b, 12a,
12b is an optical transmission cable connector, and 13 is an optical transmission cable.

The operation inside the optical rotary encoder will be described below. Due to the rotation of the circular shading plate 2 directly connected to the motor shaft 1, the light projected from the end 10 of the optical transmission cable passes through the slit plate 4 and the circular shading plate 2, and the light receiving port 5
Is input as a pulse signal. The pulse signal is output to the outside by the optical transmission cable 13. As an example, the feedback system shown in FIG. 6 is configured.

FIG. 6 shows a feedback system according to the third embodiment of the present invention. 13 is an optical transmission cable, 21 is a motor drive unit, 22a is a position feedback comparison unit, 22
b is a speed feedback comparison unit, 23a is a position gain unit, 23b is a speed gain unit, 25 is an optical inverse converter, 26 is a digital / analog converter, 27 is a motor cable,
29 is a light source for an optical rotary encoder, 31 is a position command, 32a is a position feedback signal, 32b is a speed feedback signal, 33a is a speed command, 33b is a current command, 41 is a motor, 44 is an optical rotary encoder,
Reference numeral 51 is a numerical control device, 56 is a positioning control device, and 57 is a servomotor.

The operation of the feedback system will be described below. A position command 31 from the numerical controller 51 and a position feedback signal 32 from the optical rotary encoder 44.
The position feedback comparison unit 22a performs comparison with a,
The position gain section 23a outputs the speed command 33a, and the speed feedback comparison section 22b compares the speed command 33a with the speed feedback signal 32b from the optical rotary encoder 44, and the speed gain section 23b outputs the current command 33b. To do. The motor drive unit 21 drives the motor 41 based on the current command 33b, and the pulse signal from the optical rotary encoder 44 generated by the rotation of the motor 41 is converted into a position feedback signal by the optical inverse converter 25 and the digital / analog converter 26. 32a and velocity feedback signal 32b.

As described above, according to this embodiment, the optical transmission cable 13 is connected to the light receiving portion of the optical rotary encoder 44.
Is arranged and the pulse signal of the optical rotary encoder 44 is transmitted by optical transmission, whereby the optical transmission cable 13
Even when the motor cable 27 and the motor cable 27 are close to each other, electromagnetic induction peculiar to the electric wire is not induced, and highly reliable positioning control without intervening noise can be performed.

[0029]

As described above, according to the present invention, the rotation speed and the rotation direction of the motor are optically detected as an output signal of the optical rotary encoder, and the output signal is transmitted to the positioning control device by optical transmission or spatial transmission. ,
It is possible to perform highly reliable positioning control that does not involve noise.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical rotary encoder according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a feedback system in the first embodiment of the present invention.

FIG. 3 is a sectional view of an optical rotary encoder according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a feedback system in a second embodiment of the present invention.

FIG. 5 is a sectional view of an optical rotary encoder according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing a feedback system in a third embodiment of the present invention.

FIG. 7 is a sectional view of an optical rotary encoder in a conventional example.

FIG. 8 is a block diagram showing a feedback system in a conventional example.

FIG. 9 is a three-dimensional layout diagram of main components of an optical rotary encoder in a conventional example.

[Explanation of symbols]

1 Motor Shaft 2 Circular Light-shielding Plate 3 Light-Emitting Element 4 Slit Plate 5 Light-Reception Port 6 (Composite Cable of Optical Transmission Cable and Power Supply Wire) 7 Light-Receiving Element 8 Transmitter 9 Optical Rotary Encoder Power Cable 10 Optical Transmission Cable Terminal 11a Optical transmission cable connector 11b Optical transmission cable connector 12a Optical transmission cable connector 12b Optical transmission cable connector 13 Optical transmission cable 21 Motor drive unit 22a Position feedback comparison unit 22b Speed feedback comparison unit 23a Position gain unit 23b Speed gain unit 24 Optical Rotary Encoder Power Supply 25 Optical Inverse Converter 26 Digital / Analog Converter 27 Motor Cable 28 Receiver 29 Optical Rotary Encoder Light Source 31 Position Command 32a Position Feedback Signal 32b Speed Feedback signal 33a Speed command 33b Current command 41 Motor 42 Optical rotary encoder 43 Optical rotary encoder 44 Optical rotary encoder 51 Numerical control device 52 Positioning control device 53 Servo motor 54 Positioning control device 55 Servo motor 56 Positioning control device 57 Servo motor 101 Shaft 102 Circular Light-shielding Plate 103 Light-Emitting Element 104 Slit Plate 107 Light-Receiving Element 114 Signal Cable 121 Motor Driving Section 122a Comparison Section 122b Comparison Section 123a Position Gain Section 123b Speed Gain Section 124 Optical Rotary Encoder Power Supply 126 Digital / Analog Converter 127 Motor cable 131 Position command 132a Position feedback signal 132b Speed feedback signal 133a Speed command 1 3b the current instruction 141 motor 142 optical rotary encoder 151 numerical controller 152 positioning control device 153 servomotor

Claims (3)

[Claims] 1. A light source, a circular light-shielding plate directly connected and fixed to a motor shaft, a light-receiving unit arranged so as to face the light source through the circular light-shielding plate, and an output signal obtained by the light-receiving unit. An optical rotary encoder for transmitting to the outside, wherein an output signal obtained by rotating the circular light shielding plate is transmitted by an optical transmission cable. 2. The optical rotary encoder according to claim 1, wherein the light receiving portion has a transmitter, and the output signal obtained by rotating the circular light shielding plate is transmitted by spatial transmission. 3. The optical rotary encoder according to claim 1, further comprising an optical transmission cable for introducing light from an external light source.