JPH05307411A - Encoder device - Google Patents

Abstract

PURPOSE:To considerably improve the positioning precision of an encoder device. CONSTITUTION:A rotary encoder is provided with a disk 22 which is coaxially fixed to the rotary shaft of a pulse motor, and a transmission hole strings 23, 24 and 25 along the direction of a periphery are formed on the disk 22. The transmission hole strings 23 and 24 consist of several tens to several hundreds of transmission holes 26, and the transmission holes 26 of the transmission hole strings 23 and 24 are formed by mutually different arrangement pitches. The transmission hole string 25 consists of two transmission holes 26 formed at point-symmetrical positions on the diameter line of the disk 22. optical sensors 29a, 29b and 29c consisting of light-emitting elements 27a, 27b and 27c and light-receiving elements 28a, 28b and 28c are arranged in accordance with the respective transmission hole strings 23-25, and the transmission holes 26 of the respective transmission hole strings 23-25 are respectively detected by the optical sensors 29a, 29b and 29c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder device, and more particularly to an encoder device for detecting the rotation speed and rotation angle of a member.

[0002]

2. Description of the Related Art When driving an industrial robot, it is necessary to detect the rotational speed or the rotational angle of each drive shaft as accurately as possible. Therefore, each drive shaft of the industrial robot is provided with a rotary encoder (hereinafter, referred to as an encoder) for detecting the rotation speed and the rotation angle of the drive shaft. In this encoder, a disk fixed coaxially with the drive shaft is provided with a plurality of rows of a plurality of through holes arranged along the circumferential direction. The rows of through holes corresponding to the A-phase and the B-phase have several tens to several 1 per row
The rotation direction and the rotation angle of the drive shaft are detected by detecting 00 holes at different positions in the circumferential direction and detecting these through holes with an optical sensor including a light emitting element and a light receiving element as an example.

Further, only one through hole row is formed on the disc along the circumferential direction. This through hole array is a disk, and therefore outputs one pulse per one rotation of the drive shaft, and the timing at which the pulse is generated is fixed at one position along the circumferential direction of the drive shaft. It is set as an origin along the circumferential direction of the drive shaft.

FIG. 2 is a system diagram of the robot 1 which is the premise of the present invention. The robot 1 includes a support plate 2 having a long plate shape, and end plates 3 and 4 provided at both ends of the support plate 2 perpendicularly to the support plate 2.
One end of the ball screw 5 is rotatably supported by the end plate 3, and the end plate 4 is rotatably supported by the ball screw 5 penetrating therethrough. A slider 6 is attached to the ball screw 5 between the end plates 3 and 4, and is translated in parallel with the arrow A1 direction or the opposite direction according to the bidirectional rotation of the ball screw 5, and is fixed between the end plates 3 and 4, for example. It is held so as not to rotate around the ball screw 5 by a rail (not shown) or the like. On the support plate 2, at a predetermined position in the arrow A1 direction,
A limit switch 17 for positioning the slider 6 in the arrow A1 direction is provided.

The outer end of the end plate 4 of the ball screw 5 is fixed to the rotor of the pulse motor 7 and is rotationally driven bidirectionally by the pulse motor 7. An encoder 8 is attached to the pulse motor 7. A configuration example of the encoder 8 of the conventional example is shown in FIG. 5, and an output signal example thereof is shown in FIG. The encoder 8 includes a disk 9 coaxially fixed to the rotation shaft of the pulse motor 7, and the disk 7 is formed with rows of through holes 10, 11, 12 along the circumferential direction. Through hole row 10, 11
Is composed of several tens to several hundreds of through holes 13, and each through hole row 1
The 0 and 11 through holes 13 are formed at mutually different arrangement pitches, and the through hole row 12 is composed of only a single through hole 13. Corresponding to each of the through hole rows 10 to 12, the light emitting elements 14a, 14b, 1
4c and the photosensors 16a, 16b, 16c composed of the light receiving elements 15a, 15b, 15c are arranged, and each through hole array 1
The through holes 13 of 0 to 12 are the optical sensors 16a, 16b, 1
6c respectively detect. Each optical sensor 16a,
Examples of output signals of 16b and 16c are shown in FIG. 5 (1), FIG. 5 (2) and FIG. 5 (3), respectively.

The control unit 18 for controlling the rotation state of the pulse motor 7 based on the processing result by inputting the output signal from each of the optical sensors 16a, 16b, 16c and the signal from the limit switch 17 for signal processing. It is provided. That is, in the conventional encoder 8, the pulse motor 7 is rotated, the slider 6 passes through the installation position of the limit switch 17, and the output signal S1 from the limit switch 17 is first output. Positioning pulse P1
The position of the slider 6 at the time when is output is the origin A in the direction of the arrow A1. On the other hand, 1 of the pulse motor 7
Within the rotation, a number of pulses P2 and P3 corresponding to the number of the through holes 13 of the through hole arrays 10 and 11 are output as shown in FIG. 5 (2) and FIG. 5 (3). The rotation direction, rotation speed, and rotation angle of the pulse motor 7 are detected.

[0007]

In the conventional robot 1 described above, the ball screw 5 has a screw pitch of 20 as an example.
In the case of mm / revolution, using the encoder 8 of the conventional example, the positioning of the slider 6 in the direction of the arrow A1 can be set only every one revolution of the pulse motor 7, that is, every 20 mm. Therefore, there is a problem that the positioning accuracy of the encoder 8 is low when the origin of operation of the robot 1 is set or changed.

An object of the present invention is to solve the above technical problems and to provide an encoder device in which the positioning accuracy is remarkably improved.

[0009]

SUMMARY OF THE INVENTION The present invention is a rotating body driven by rotation, wherein a plurality of first angle identifying means are formed along the circumferential direction, and the first angles having different arrangement pitches. A rotating body in which rows of the identifying means are arranged in the radial direction and at least two second angle identifying means are formed along the circumferential direction, a first angle identifying means and a second angle identifying means of the rotating body, respectively. An encoder device, comprising: an angle detection unit that detects and outputs an A-phase, B-phase, and Z-phase angle signal.

[0010]

[Operation] An encoder device according to the present invention comprises a rotating body,
By detecting the angle identification means formed on the rotating body, A
Angle detection means for outputting angle signals of phase B, phase B, and phase Z. On the rotating body, a plurality of first angle identifying means are formed along the circumferential direction, and rows of the first angle identifying means having different arrangement pitches are arranged in the radial direction.
At least two second angle identifying means are formed along the circumferential direction. The angle detecting means detects the first angle identifying means and the second angle identifying means of the rotating body, respectively, and
Outputs phase, B-phase, and Z-phase angle signals.

Therefore, the encoder device of the present invention can output a plurality of Z-phase angle signals within one rotation of the rotating body. As a result, circumferential positioning in the encoder device can be performed at a plurality of positions within 360 degrees of the rotating body, and the positioning accuracy when setting the origin of the encoder device can be significantly improved.

[0012]

1 is a system diagram showing the features of a rotary encoder (hereinafter referred to as an encoder) 21 according to an embodiment of the present invention, and FIG. 2 is a system diagram of an industrial robot having a structure which is the premise of the present invention. Is. The rotary encoder 21 is used in place of the conventional encoder 8 in the industrial robot 1 having the configuration described in the section of the conventional example. The configuration of the robot 1 except for the internal configuration of the rotary encoder 21 is the same as the description in the section of the related art, and the description thereof will be omitted. The encoder 21 of the present embodiment includes a disc 22 coaxially fixed to the rotation shaft of the pulse motor 7, and the disc 22 is formed with rows of through holes 23, 24, 25 along the circumferential direction. Through hole row 2
Reference numerals 3 and 24 are each composed of several tens to several hundreds of through holes 26. The through holes 26 of each of the through hole rows 23 and 24 are formed at mutually different arrangement pitches, and the through hole rows 25 are on the diameter line of the disc 22. It is composed of two through holes 26 formed at point-symmetrical positions. The light emitting elements 27a, 27b, 27c corresponding to the through hole rows 23 to 25, respectively.
And optical sensors 29a, 29b, 29c composed of light receiving elements 28a, 28b, 28c are arranged, and the through hole rows 23 to
The through holes 26 of 25 are the optical sensors 29a, 29b, 29c.
Respectively detected by.

The control unit 18 for controlling the rotation state of the pulse motor 7 based on the processing result by inputting the output signal from each of the optical sensors 16a, 16b, 16c and the signal from the limit switch 17 for signal processing. It is provided.

FIG. 3 is a block diagram of the encoder 21 of this embodiment.
3 is a waveform diagram illustrating the operation of FIG. Disc 22 as described above
From the encoder 21 having, the angle signals of A phase, B phase, and Z phase shown in FIG. 3 (1), FIG. 3 (2), and FIG. 3 (3) are output. Here, the limit switch 1
7 is used to set the origin of the slider 6 along the arrow A1 direction, and after the slider 6 operates the limit switch 17 at time t1 as shown in FIG.
When the output timing of the first Z-phase angle signal Pa after that is set to the origin of the rotation direction, the origin of the control of the slider 6 is a position A separated from the limit switch 17 by a distance L1 as shown in FIG. Become. The encoder 21 outputs the output timing of the second Z-phase angle detection pulse Pb after time t1.
3, the slider control origin is set to a position B, which is a distance L2 from the limit switch 17, as shown in FIG.

In the case of the present embodiment, the Z-phase angle pulse is output every half rotation of the disc 22. Therefore, the accuracy regarding the position of the slider of the encoder is 10 mm, and it is possible to achieve the accuracy twice as high as the conventional one.

FIG. 4 shows a timing chart of an output example of the encoder of another embodiment of the present invention. In this embodiment, the through holes 26 of the third through hole row 25 of the disc 22 in FIG.
Are formed at intervals of 60 degrees. In the case of this embodiment, the positioning accuracy of the slider 6 by the Z-phase angle pulse is 5 mm in the arrow A1 direction, and it is possible to achieve the accuracy four times higher than that of the conventional example.

Further, the Z-phase angle pulse generation interval of the present invention is not limited to the 180-degree interval or the 60-degree interval in each of the above-mentioned embodiments, and may be any interval, and the object for which the encoder 21 is used. Also, the robot 1 is not limited to the example of performing the parallel movement like the robot 1 shown in FIG. 2, and may perform other operations such as rotational movement.

[0018]

As described above, according to the present invention, the encoder device detects the rotating body and the angle identifying means formed on the rotating body, and outputs the A-phase, B-phase, and Z-phase angle signals. Angle detecting means for A plurality of first angle identifying means are formed on the rotating body along the circumferential direction, and rows of the first angle identifying means having different arrangement pitches are arranged in the radial direction, and at least 2 are arranged along the circumferential direction. Second one
Angle identifying means is formed. The angle detecting means detects the first angle identifying means and the second angle identifying means of the rotating body, respectively, and outputs the A-phase, B-phase, and Z-phase angle signals, respectively.

Therefore, in the encoder device of the present invention,
A plurality of Z-phase angle signals can be output within one rotation of the rotating body. As a result, circumferential positioning in the encoder device can be performed at a plurality of positions within 360 degrees of the rotating body, and positioning accuracy when setting the origin of the encoder device can be significantly improved.

[Brief description of drawings]

FIG. 1 is a system diagram of a rotary encoder 21 according to an embodiment of the present invention.

FIG. 2 is a front view of an industrial robot 1 which is a premise of the present invention.

FIG. 3 is a timing chart of the present embodiment.

FIG. 4 is a timing chart of another embodiment of the present invention.

FIG. 5 is a system diagram of a conventional encoder 8.

FIG. 6 is a timing chart of a conventional example.

[Explanation of Codes] 1 industrial robot 6 slider 7 pulse motor 21 encoder 22 disk 23-25 through hole array 26 through hole 29a, 29b, 29c optical sensor

Claims (1)

[Claims] 1. A rotating body driven to rotate, wherein a plurality of first angle identifying means are formed along a circumferential direction, and rows of the first angle identifying means having mutually different arrangement pitches are arranged in a radial direction. A rotating body which is arranged and has at least two second angle discriminating means formed along the circumferential direction, and a first angle discriminating means and a second angle discriminating means of the rotating body are respectively detected to detect A phase and B phase. An encoder device, comprising: an angle detection unit that outputs a phase signal and a Z-phase angle signal.