JP2006226774A - Angular acceleration detector and speed detection method using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an angular acceleration detector for improving speed detection resolution at a low rotation speed, speed responsiveness, and servo performance, and also provide a speed detection method using it. <P>SOLUTION: The angular acceleration detector comprises a disc 2 for position detection that is mounted on a motor shaft and has a slit 8 for position detection and a slit 9 for angular acceleration detection, a disc 6 for angular acceleration detection that is mounted to the motor shaft via an elastic body 5 and has the same slit at the same position as that of the slit 9 for angular acceleration detection, a first light emitting diode 1 for radiating light to the slit 8 for position detection on the motor shaft side, a first photo diode 3 that receives light having passed the slit 8 and is disposed on a stator side, a second light emitting diode 4 for radiating light to the slit 9 for angular acceleration detection on the motor shaft side, and a second photo diode 7 that receives light having passed the slit 9 and is disposed on the stator side. The elastic body 5 is provided with an elastic viscous body in the restricting direction of deformation of the elastic body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an angular acceleration detector and a detection speed correction method of a speed detection method using the angular acceleration detector to correct the rotational speed of a servo motor using the angular acceleration detector.

In the conventional speed detection, the output of the angle detector is obtained by time differentiation. Moreover, as a prior art of an angular acceleration detector, for example, there is JP-A-10-153613. This is a first disk fixed coaxially so as to rotate integrally with the rotating body, and fixed coaxially so as to rotate integrally with the rotating body facing this first disk. In the angular acceleration sensor comprising the second disc, the first slit row concentrically formed on the first disc at a predetermined interval, and the first slit row in the second disc are opposed to each other. A second slit row that is formed in a circumferential direction at a position and intersects the first slit row with a variable area, and a position where the second slit row is formed on the second disk. And an annular weight portion formed on at least one of the inner side and the outer side in the radial direction, and the second disk is formed on the inner side in the radial direction from the position where the weight portion and the second slit row are formed. And elastic deformation toward the circumferential direction An elastic body portion of capacity, is made of a means for detecting a change in the cross area of the second slit rows for said first slit rows generated by the rotation of the rotating body.
Further, the detection means for detecting the angular acceleration includes a light emitting element and a light quantity detection means arranged so as to sandwich the first and second slit rows from both sides, and an integral multiple of the first and second slit pitches. The transmission light limiting slit having a transmission width of 1 mm is provided, and the amount of transmitted light passing through the first slit row and the second slit row is detected.
FIG. 5 is a block diagram showing a conventional speed closed loop. In the figure, 13 is an angle detector, 14 is a detected rotation angle signal, 15 is a differentiator, 16 is a detected speed signal, and 22 is a differential amplifier that obtains and amplifies the deviation between the speed command and the detected speed signal. The speed deviation is input to the power converter and the speed of the motor is controlled.
Japanese Patent Laid-Open No. 10-153613

However, the conventional speed detection method has a problem that speed detection at a low rotational speed is low if the resolution of the angle detector is not high, and the speed detection resolution is low, resulting in poor servo performance when used in a servo system. It was.
In addition, since the conventional angular acceleration detector uses the maximum angular acceleration from the stop as the detection range, the detection resolution at low acceleration is low, and if an impact exceeding the assumed maximum angular acceleration is applied, the detector is erroneously detected. Or damage.
The present invention has been made in view of such problems, and provides an angular acceleration detector that improves speed detection resolution, speed response, and servo performance at a low rotational speed, and a speed detection method using the same. For the purpose.

In order to solve the above problems, the present invention comprises the following means.
A position detection disk 2 provided with a position detection slit 8 and an angular acceleration detection slit 9 attached to the motor shaft, and attached to the motor shaft via an elastic body 5 at the same position as the angular acceleration detection slit 9. An angular acceleration detecting disk 6 having the same slit, a first light emitting diode 1 for irradiating light to the position detecting slit 8 on the motor shaft side, and a stator for receiving light passing through the position detecting slit 8 The first photodiode 3 provided on the side, the second light emitting diode 4 for irradiating the angular acceleration detecting slit 9 on the motor shaft side, and the light that has passed through the angular acceleration detecting slit 9 are received. In the angular acceleration detector including the second photodiode 7 provided on the stator side, an elastic viscous body is provided in the elastic body 5 in a direction that restricts deformation of the elastic body. Than it is.

The angular acceleration detector according to claim 1, further comprising a stopper for stopping elastic deformation of the elastic body 5 in a direction in which the elastic body 5 is deformed.
Further, the position detecting disk 2 provided with the position detecting slit 8 and the angular acceleration detecting slit 9 attached to the motor shaft, and the same as the angular acceleration detecting slit 9 attached to the motor shaft via the elastic body 5. The angular acceleration detecting disk 6 having the same slit at the position, the first light emitting diode 1 for irradiating the position detecting slit 8 on the motor shaft side, and the light passing through the position detecting slit 8 are received. The first photodiode 3 provided on the stator side, the second light emitting diode 4 for irradiating the angular acceleration detection slit 9 on the motor shaft side, and the light that has passed through the angular acceleration detection slit 9 A speed detection method for obtaining a detection speed by differentiating the output signal of the angle detector using an angular acceleration detector comprising a second photodiode 7 provided on the stator side for receiving light. In is for said detected speed, a speed signal which the angular acceleration signal obtained by adding the speed signal obtained by integrating from the angular acceleration detector 17.
The speed detection method according to claim 3, wherein the angular acceleration signal from the angular acceleration detector 17 is integrated to obtain a speed signal, and the speed signal is passed through a high-pass filter.
According to the present invention, in the angular acceleration detection method of the angular acceleration detector, when the light emitted from the first light emitting diode 1 passes through the slit of the position detecting disk 2 and the motor shaft is accelerating, the elastic body Is deformed, and the angular acceleration detection disk 6 is displaced from the position detection disk 2 so that the amount of light passing therethrough is changed, the voltage is converted by the first and second light emitting diodes, and the elasticity is changed. Since the body 5 has a mechanism for restricting deformation, a detection value with high resolution can be obtained at low acceleration, and a detection value obtained by removing residual vibration due to a sudden change in angular acceleration can be obtained because it has viscosity.

  In the present invention, the output of the angular acceleration detector is integrated by the integrator, and low frequency is removed by the high pass filter, and the output of the angle detector is differentiated by the differentiator. Thus, the speed detection is corrected. For this reason, speed detection resolution at low rotational speed is improved, speed response is improved, and servo performance can be improved.

  According to the method of the present invention, it is possible to provide an angular acceleration detector that improves speed detection resolution, speed response, and servo performance at a low rotational speed, and a speed detection method using the same.

  Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of an angle detector and an angular acceleration detector that implement the method of the present invention. In the figure, 1 is a first light emitting diode, 4 is a second light emitting diode, 2 is a position detection disk, 3 is a first photodiode, 5 is an elastic body, 6 is an angular acceleration detection disk, and 7 is a second photodiode. It is. The position detection disk 2, the elastic body 5, and the angular acceleration detection disk 6 are attached to the motor rotor 10 side and rotate together with the motor rotor 10. The first light-emitting diode 1 and the second light-emitting diode 4 are positioned on the motor rotor 10 via bearings, but do not rotate and are attached to a fixed frame. On the other hand, the first photodiode 3 and the second photodiode 7 are attached to a fixed frame. The position detection disk 2 is provided with a position detection slit 8 and an angular acceleration detection slit 9. The angular acceleration detection disk 6 is provided with angular acceleration detection slits 9 having the same number of slits and the same pitch as the angular acceleration detection slits 9 in the position detection disk 2.
With this structure, the light emitted from the first light emitting diode 1 can be received by the first photodiode 3 through the position detecting disk 2.
Next, the light emitted from the second light emitting diode 4 is received by the second photodiode 7 through the position detecting disk 2 and the angular acceleration detecting disk 6 connected to the motor shaft via the elastic body 5. ing.

  FIG. 2 is a detailed view of the elastic body 5 of FIG. 1, which has an inner ring 5a and an outer ring 5b, and has a stopper 5d for limiting deformation. The elastic viscous body 5c sandwiched between the inner ring 5a and the outer ring 5b is a viscous elastic body or a combination of an elastic body and a viscous body, and has an appropriate damping effect.

  FIG. 3 shows slit shapes of the position detection disk 2 and the angular acceleration detection disk 6 of FIG. The position detection slit 8 is provided in the position detection disk 2, and the angular acceleration detection slit 9 is provided in the same shape in both the position detection disk 2 and the angular acceleration detection disk 6.

  FIGS. 4A to 4C are diagrams illustrating the operation of angular acceleration detection. At a constant speed (a), the angular acceleration detection disk does not bend, and the angular acceleration detection slit 9 (hereinafter referred to as the upper slit) of the angular acceleration detection disk 6 and the angular acceleration detection slit 9 ( Hereinafter, the amount of light passing through the lower slit) is set to 50%. At the time of forward acceleration (b), the elastic body 5 attached to the angular acceleration detecting disk 6 is bent, and the light passing through the upper slit and the lower slit becomes 30%. Further, at the time of reverse acceleration (c), the light is deflected in the opposite direction to (b), and the light passing through the upper slit and the lower slit becomes 70%. Thus, the passing light from the second light emitting diode 4 in FIG. 1 to the second photodiode 7 changes due to the angular acceleration of the motor, and the angular acceleration can be detected from the voltage of the second photodiode 7. .

  A rotation speed 14 output from the angle detector 13 in FIG. 6 is differentiated by a differentiator 15 as a detection speed, and an angular acceleration 18 output from the angular acceleration detector 17 is integrated by an integrator 19 is a high-pass filter. By using 20 as the correction speed and adding it to the detection speed, a high resolution speed can be detected.

Cross section of angle detector and angular acceleration detector Detailed view of elastic body Diagram showing slit shape Operational illustration of angular acceleration detection Block diagram showing a conventional closed speed loop The block diagram which shows the detection speed correction method of the speed detector which implements the method of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st light emitting diode 2 Position detection disk 3 1st photodiode 4 2nd light emitting diode 5 Elastic body 5a Inner ring 5b Outer ring 5c Elastic viscous body 5d Stopper 6 Angular acceleration detection disk 7 Second photodiode 8 Position detection slit 9 Angular acceleration detection slit 10 Motor rotor 13 Angle detector 14 Rotation angle 15 Differentiator 16 Detection speed 17 Angular acceleration detector 18 Angular acceleration 19 Integrator 20 High-pass filter 22 Differential amplifier 21 Adder 23 Power converter

Claims (4)

A position detection disk (2) provided with a position detection slit (8) and an angular acceleration detection slit (9) attached to the motor shaft, and the angular acceleration attached to the motor shaft via an elastic body (5). An angular acceleration detection disk (6) having the same slit at the same position as the detection slit (9), and a first light emitting diode (1) for irradiating light to the position detection slit (8) on the motor shaft side, Irradiating light to the first photodiode (3) provided on the stator side that receives the light that has passed through the position detection slit (8) and the angular acceleration detection slit (9) on the motor shaft side An angular acceleration detector comprising: a second light emitting diode (4) configured to be connected; and a second photodiode (7) provided on a stator side that receives light that has passed through the angular acceleration detection slit (9).
An angular acceleration detector characterized in that an elastic viscous body is provided in the elastic body (5) in a direction to limit deformation of the elastic body.   The angular acceleration detector according to claim 1, wherein a stopper for stopping elastic deformation of the elastic body (5) is provided in a direction in which the elastic body (5) is deformed. A position detection disk (2) provided with a position detection slit (8) and an angular acceleration detection slit (9) attached to the motor shaft, and the angular acceleration attached to the motor shaft via an elastic body (5). An angular acceleration detection disk (6) having the same slit at the same position as the detection slit (9), and a first light emitting diode (1) for irradiating light to the position detection slit (8) on the motor shaft side, Irradiating light to the first photodiode (3) provided on the stator side that receives the light that has passed through the position detection slit (8) and the angular acceleration detection slit (9) on the motor shaft side An angular acceleration detector comprising a second light emitting diode (4) that performs the above and a second photodiode (7) provided on the stator side that receives light that has passed through the angular acceleration detection slit (9), Differentiate the output signal of the angle detector to find the detection speed In the speed detection method
A speed detection method using an angular acceleration detector, characterized in that a speed signal is obtained by adding the detected speed and a speed signal obtained by integrating the angular acceleration signal from the angular acceleration detector (17). . A velocity signal is obtained by integrating the angular acceleration signal from the angular acceleration detector (17);
4. The speed detection method using an angular acceleration detector according to claim 3, wherein the speed signal is passed through a high-pass filter.

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