JP4235897B2 - Multi-rotation detection method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a batteryless multi-rotation amount detection method and apparatus for detecting the multi-rotation amount of a servo motor used for a robot, a machine tool, and the like by an absolute angle.
[0002]
[Prior art]
The conventional multi-rotation encoder is configured as shown in FIG. In the figure, reference numeral 1 denotes a rotary machine, a first encoder 3, and a first gear 4 connected to a drive shaft 2. Reference numeral 6 denotes a second encoder, and a second gear 5 is attached to a driven shaft 7 that rotates integrally with the second encoder 6, and the second gear 5 is engaged with the first gear 4. Yes.
[0003]
When the rotary machine 1 rotates, the multi-rotation encoder configured as above is determined by the second encoder 6 based on the gear ratio between the first gear 4 on the driving side and the second gear 5 on the driven side. The number of rotations reduced according to the reduction ratio is transmitted. A conventional multi-rotation amount detection flow is shown in FIG. That is, the rotation angle of the rotary machine 1 is detected using the first encoder 3, and the multi-rotation amount T of the drive shaft 2 is detected using the second encoder 6. The multi-rotation amount T is an integer obtained by dividing the rotation angle θslv of the second encoder by the pitch angle of the second gear.
There is also a configuration in which the multi-rotation amount is measured by a magnetic coupling instead of a mechanical gear. (For example, patent document 1).
[0004]
[Patent Document 1]
JP 6-41853
[0005]
[Problems to be solved by the invention]
However, in the prior art, when the multi-rotation amount is actually detected, there is a case where a miscount occurs due to the absolute accumulated angle error of the second gear, making it impossible to measure the multi-rotation amount. . That is, there is a problem that the multi-rotation detection unit detects that the multi-rotation amount is invariant in the multi-rotation detection unit due to an insufficient rotation amount of the second gear even though the first encoder makes one rotation.
In order to solve this problem, the accumulated angle error of the speed reduction mechanism must be extremely small and highly accurate, and the angle detection device for the driven shaft must also be equipped with a very high accuracy device. Therefore, the application range of this method was narrowed.
In view of the above disadvantages of the prior art, the present invention makes it possible to measure a multi-rotation amount by correcting the multi-rotation amount even if the absolute integrated angle error of the gear of the speed reduction mechanism or the encoder of the driven shaft is large. An object of the present invention is to provide a multi-rotation amount detection method and apparatus that are easy to manufacture and inexpensive.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a first encoder for detecting an absolute rotation angle within one rotation, which is attached to a drive shaft of a rotary machine, a first gear supported on the drive shaft, and the first gear A speed reduction mechanism comprising a second gear coupled to a gear and pivotally supported by a driven shaft; a second encoder fixed to the driven shaft for detecting an absolute rotation angle; and signals of the first and second encoders A signal processing operation unit that performs processing, and detects a multi-rotation amount T of the drive shaft from an angle θdrv of the drive shaft obtained from the first encoder and an angle θslv of the driven shaft obtained from the second encoder In the multi-rotation amount detection method, the signal processing calculation unit sets a reduction ratio n of the second gear and an angle λ of the driven shaft with respect to one rotation of the drive shaft, and an angle θdrv of the first encoder. The multi-rotation amount determination parameter θslv is detected, and then the parameters tj and θds for determining the multi-rotation amount are calculated as tj = θslv / λ (where tj is an integer) and θds = n (θslv−tj), respectively. The absolute integrated angle error of the second encoder is within ± λ / 3 with respect to the drive shaft, the angle θdrv of the first encoder is 120 degrees or less, and the multi-rotation amount determination parameter θds is 240. When the angle exceeds the degree, the multi-rotation amount T is set to tj + 1, and when the first encoder angle θdrv is 120 degrees or less and the multi-rotation amount determination parameter θds is 240 degrees or less, the multi-rotation amount T Tj, and when the angle θdrv of the first encoder is more than 120 degrees and less than 240 degrees, the multi-rotation amount T is tj and the angle θ of the first encoder When rv is 240 degrees or more and the multi-rotation amount determination parameter θds is 120 degrees or less, the multi-rotation amount T is tj−1, the first encoder angle θdrv is 240 degrees or more, and When the multi-rotation amount determination parameter θds exceeds 120 degrees, the multi-rotation amount T is calculated as tj.
In addition, an initial condition setting unit that sets a reduction ratio n of the second gear and an angle λ of the driven shaft with respect to one rotation of the drive shaft, an angle θdrv of the first encoder, An angle data acquirer for detecting the angle θslv of the second encoder, and parameters tj and θds for determining the multi-rotation amount are tj = θslv / λ (where tj is an integer), θds = n (θslv−tj) A multi-rotation amount determination parameter calculator that calculates the angle θdrv of the first encoder and the multi-rotation amount determination parameter θds; a multi-rotation amount calculator that calculates the multi-rotation amount T; The absolute integrated angle error of the second encoder is within ± λ / 3 with respect to the drive shaft, and the angle determiner uses the angle θ of the first encoder. When it is determined that rv is 120 degrees or less and the multi-rotation amount determination parameter θds exceeds 240 degrees, the multi-rotation amount calculator calculates the multi-rotation amount T as tj + 1, and the angle determiner Determines that the angle θdrv of the first encoder is 120 degrees or less and the multi-rotation amount determination parameter θds is 240 degrees or less, the multi-rotation amount calculator calculates the multi-rotation amount T as tj. When the angle determiner determines that the angle θdrv of the first encoder exceeds 120 degrees and less than 240 degrees, the multi-rotation amount calculator calculates the multi-rotation amount T as tj, When the angle determiner determines that the angle θdrv of the first encoder is 240 degrees or more and the multi-rotation amount determination parameter θds is 120 degrees or less, the multi-rotation amount calculator calculates the multi-rotation amount. T is calculated as tj-1, and when the angle determiner determines that the angle θdrv of the first encoder is 240 degrees or more and the multi-rotation amount determination parameter θds exceeds 120 degrees, The multi-rotation amount calculator uses the multi-rotation amount T as tj.
With the above configuration, the multi-rotation detector including the second gear can be easily manufactured, and an integer for obtaining the multi-rotation amount can be easily obtained, so that an inexpensive multi-rotation encoder can be realized.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a flowchart showing a multi-rotation amount detection method of the present invention, and FIG. 2 is a block diagram showing a signal processing operation unit. In the figure, 8 is a signal processing calculation unit, 81 is an initial condition setting unit, 82 is an angle data acquisition unit, 83 is a multi-rotation amount determination parameter calculator, 84 is an angle determination unit, and 85 is a multi-rotation amount calculation unit. . The structure is the same as that of the conventional multi-rotation encoder shown in FIG.
The multi-rotation amount of the drive shaft 2 is calculated as follows.
(1) First, in the initial condition setting unit 81 of the signal processing calculation unit 8, the speed ratio n of the second gear 5 as an initial condition, and the angle λ of the driven shaft 7 during one rotation of the drive shaft 2 calculated from n. Set.
(2) Next, the angle data acquisition unit 82 detects and acquires the angle θdrv of the first encoder and the angle θslv of the second encoder as angle data from the first encoder 3 and the second encoder 6. To do.
(3) The multi-rotation amount determination parameter calculator 83 calculates the multi-rotation amount determination parameters tj and θds according to the flowchart.
tj = θslv / λ (where tj is an integer)
θds = θslv × n−tj × n
(4) The angle determiner 84 determines the first encoder angle θdrv and the second encoder angle θslv.
When the first encoder angle θdrv is 120 degrees or less and the multi-rotation amount determination parameter θds exceeds 240, the multi-rotation amount T of the drive shaft 2 is set to tj + 1.
When the first encoder angle θdrv is 120 degrees or less and the multi-rotation amount determination parameter θds is 240 or less, the multi-rotation amount T is set to tj.
Next, when the first encoder angle θdrv exceeds 120 degrees and is less than 240 degrees, the multi-rotation amount T is determined as tj.
Finally, when the first encoder angle θdrv is 240 degrees or more and the multirotation amount determination parameter θds is 120 or less, the multirotation amount T is set to tj−1.
When the first encoder angle θdrv is 240 degrees or more and the multi-rotation amount determination parameter θds exceeds 120 degrees, the multi-rotation amount T is set to tj.
After calculating the multi-rotation amount T in this way, in order to measure the next multi-rotation amount, the process returns to the angle data acquisition unit 82 to detect the angle θdrv of the first encoder and the angle θslv of the second encoder. .
Next, the effect of the multi-rotation amount detection method of the present invention was examined. As for the present invention and the conventional multi-rotation amount detection method, FIG. 3 shows the results of measuring the multi-rotation amount with a multi-rotation encoder at a reduction ratio of 13 and a drive shaft pitch of 10 degrees. The horizontal axis is the true multi-rotation amount given to the drive shaft of the multi-rotation encoder, and the vertical axis is the multi-rotation amount obtained from the multi-rotation encoder. The conventional method calculates three different values for a given multi-rotation amount, whereas the method of the present invention calculates one correct multi-rotation amount for a given multi-rotation amount. It can be seen that accurate detection is performed.
In the present embodiment, a mechanical gear is used for the speed reduction mechanism, but the same effect as in the present invention can be obtained by a worm gear type or a gear made of a magnetic coupling.
Furthermore, the same effect can be obtained even when a plurality of second encoders are arranged to increase the amount of multi-rotation.
[0008]
【The invention's effect】
As described above, according to the present invention, the absolute integrated angle error of the second encoder is within ± λ / 3 with respect to the drive shaft, and the parameters tj and θds for determining the multi-rotation amount are used. Since the method of calculating T is divided into three, tj + 1, tj, and tj-1, the multi-rotation amount of the drive shaft can be accurately measured. Since the integrated angle error of the speed reduction mechanism can be manufactured in a rough state, there is an effect that a small and inexpensive multi-rotation encoder with a wide application range can be provided.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a multi-rotation amount detection method of the present invention.
FIG. 2 is a block diagram showing a multi-rotation amount detection device of the present invention.
FIG. 3 is a graph showing the effect of the multi-rotation amount calculation of the present invention.
FIG. 4 is a perspective view showing a conventional multi-rotation amount detection device.
FIG. 5 is a flowchart showing a conventional multi-rotation amount detection method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotating machine 2 Drive shaft 3 1st encoder 4 1st gear 5 2nd gear 6 2nd encoder 7 Driven shaft 8 Signal processing calculating part 81 Initial condition setting unit 82 Angle data acquisition unit 83 Multiple rotation amount determination parameter Calculator 84 Angle determiner 85 Multi-rotation calculator

Claims (3)

A first encoder attached to a drive shaft of a rotary machine for detecting an absolute rotation angle within one rotation, a first gear supported by the drive shaft, and a gear coupled to the gear and supported by a driven shaft. A speed reduction mechanism comprising a second gear, a second encoder fixed to the driven shaft and detecting an absolute rotation angle thereof, and a signal processing operation unit for performing signal processing of the first and second encoders, In the multi-rotation amount detection method for detecting the multi-rotation amount T of the drive shaft from the angle θdrv of the drive shaft obtained from the first encoder and the angle θslv of the driven shaft obtained from the second encoder,
The signal processing calculation unit sets a reduction ratio n of the second gear and an angle λ of the driven shaft with respect to one rotation of the drive shaft, and sets an angle θdrv of the first encoder and an angle θslv of the second encoder. The parameters tj and θds for detecting and then determining the multi-rotation amount are calculated as tj = θslv / λ (where tj is an integer) and θds = n (θslv−tj), respectively, and the absolute integration of the second encoder When the angle error is within ± λ / 3 with respect to the drive shaft, the angle θdrv of the first encoder is 120 degrees or less, and the multi-rotation amount determination parameter θds exceeds 240 degrees, the multi-rotation When the amount T is tj + 1, the angle θdrv of the first encoder is 120 degrees or less, and the multi-rotation amount determination parameter θds is 240 degrees or less, the multi-rotation amount T is set to tj When the angle θdrv of the first encoder is more than 120 degrees and less than 240 degrees, the multi-rotation amount T is tj, the angle θdrv of the first encoder is 240 degrees or more, and the When the rotation amount determination parameter θds is 120 degrees or less, the multi-rotation amount T is set to tj−1, the angle θdrv of the first encoder is 240 degrees or more, and the multi-rotation amount determination parameter θds is 120 degrees. If it exceeds, the multi-rotation amount T is calculated as tj. A first encoder attached to a drive shaft of a rotary machine for detecting an absolute rotation angle within one rotation, a first gear supported by the drive shaft, and a gear coupled to the gear and supported by a driven shaft. A speed reduction mechanism comprising a second gear, a second encoder fixed to the driven shaft and detecting an absolute rotation angle thereof, and a signal processing operation unit for performing signal processing of the first and second encoders, In the multi-rotation amount detection device that detects the multi-rotation amount T of the drive shaft from the angle θdrv of the drive shaft obtained from the first encoder and the angle θslv of the driven shaft obtained from the second encoder,
The signal processing calculation unit includes an initial condition setting unit that sets a reduction ratio n of the second gear and an angle λ of the driven shaft with respect to one rotation of the drive shaft, an angle θdrv of the first encoder, and the multiple rotation amount. The angle data acquisition unit for detecting the determination parameter θslv, and the multi-rotations for calculating the multi-rotation amount parameters tj and θds as tj = θslv / λ (where tj is an integer) and θds = n (θslv−tj), respectively. An amount determination parameter calculator, an angle determiner for determining the angle θdrv of the first encoder and the multiple rotation amount determination parameter θds, and a multiple rotation amount calculator for calculating the multiple rotation amount T. The absolute integrated angle error of the encoder 2 is within ± λ / 3 with respect to the drive shaft, and the angle determiner determines that the angle θdrv of the first encoder is 120 degrees or less. And when it is determined that the multi-rotation amount determination parameter θds exceeds 240 degrees, the multi-rotation amount calculator calculates the multi-rotation amount T as tj + 1, and the angle determiner calculates the first encoder. When the angle θdrv is determined to be 120 degrees or less and the multi-rotation amount determination parameter θds is determined to be 240 degrees or less, the multi-rotation amount calculator calculates the multi-rotation amount T as tj, and the angle determiner If the angle θdrv of the first encoder is determined to be greater than 120 degrees and less than 240 degrees, the multi-rotation amount calculator calculates the multi-rotation amount T as tj, and the angle determiner When the angle θdrv of the encoder is determined to be 240 degrees or more and the multi-rotation amount determination parameter θds is determined to be 120 degrees or less, the multi-rotation amount calculator calculates the multi-rotation amount T as tj−1. ,in front When the angle determination unit determines that the angle θdrv of the first encoder is 240 degrees or more and determines that the multi-rotation amount determination parameter θds exceeds 120 degrees, the multi-rotation amount calculator calculates the multi-rotation amount calculator A multi-rotation amount detection device, wherein the amount T is tj. The multi-rotation amount detection device according to claim 2, wherein the gear includes a magnetic coupling.

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