DE102011076263B4 - Rotation angle positioning device - Google Patents

Abstract

A rotation angle positioning device (6) comprising: a rotation angle detecting device (7) having a detection target ring (8) provided on a rotating shaft (3a) and having a plurality of teeth (8a) formed at a predetermined pitch, and an angle detection sensor (9) arranged to face the teeth (8a) and generating an output according to a distance from the teeth (8a) and detecting a rotation angle of the detection target ring (8). determined based on the output from the angle detection sensor (9); anda rotating shaft driving device (10) which rotates the rotating shaft (3a) so that the rotating angle becomes a given command value (α) for the rotating angle, wherein the rotating angle positioning device (6) comprises:an error pattern storage unit (11a) which stores a pitch error pattern (F) consisting of discrepancies between rotation angles detected by the angle detection sensor (9) and actual rotation angles corresponding to the respective correction dividing points of an arbitrary pitch period in the detection target ring (8), and a command value A correcting unit (11b) which corrects the rotation angle command value (α) based on the pitch period error pattern (F) to obtain a corrected rotation angle command value (α2).

Description

Background of the Invention

1. Field of the Invention

The present invention relates to a rotation angle positioning device that positions a rotation shaft such as a machine tool at a predetermined angular position, and more particularly to an improvement in a method for correcting an error of a rotation angle detecting sensor.

2. Description of Related Art

Rotational angle positioning devices for positioning a rotational shaft of a machine tool, such as a spindle of a lathe on which a chuck is mounted, at a predetermined angular position include a device provided with a rotational angle detecting device that detects a rotational angle of the spindle, and is provided with a driving device that rotationally drives the spindle so that the rotational angle of the spindle detected by the rotational angle detection device becomes a rotational angle command value.

As the aforesaid conventional rotation angle detecting device for the spindle, Japanese Patent Application Laid-Open JP H05-288573 A, for example, proposes a device using a detection target ring attached to the spindle and a plurality of teeth formed in a predetermined distance, and an angle detection sensor which is disposed at a position facing the teeth of the detection target ring and outputs a voltage signal according to its distance from the teeth of the detection target ring.

Other examples of rotation angle detection devices are in the DE 102 48 200 A1 and US 2006/0 125 439 A1.

Summary of the Invention

However, the above-mentioned conventional rotation angle detection device has a problem that between the actual rotation angle of the spindle and the value detected by the angle detection sensor, a rotation period error in one rotation of the detection ring, which is due to the deviation of the center of the detection target ring or the like, and further, a tooth-to-tooth period error due to machining accuracy of the teeth of the detection target ring or the like occurs in every pitch period.

As for the correction of the rotation period error, it is possible to implement the correction by first detecting detection errors of the angle detection sensor at correction dividing points with which a rotation period (360°) of the detection target ring is divided into a plurality of segments and a command value for the rotation angle is corrected based on the errors.

• 360° : Anzahl von Zähnen : Anzahl von Korrektur-Unterteilungen = 0.0439453125°.

As for the correction of the pitch error, there arises a problem that currently available rotation angle positioning devices cannot cope with the correction because the number of decimal places of an interval (°) between the correction dividing points in one pitch period is too large. To give a concrete example, when the number of teeth is 512 and the number of correction divisions is 16, the interval (°) between the correction division points is given by:

• 360° : number of teeth : number of correction subdivisions = 0.0439453125°.

• Anzahl von Korrekturpunkten = Anzahl von Zähnen x Anzahl von Korrektur-Unterteilungen = 8,192,

und es entsteht dahingehend ein Problem, dass eine zu große Anzahl der Korrektur-Punkte die Verarbeitung behindert.If the mentioned method for correcting the rotational period error is used as it is for the correction of the pitch error when the number of teeth is 512 and the number of correcting divisions is 16, then:

• number of correction points = number of teeth x number of correction subdivisions = 8.192,

and there arises a problem that too large a number of the correction points hampers the processing.

An object of the present invention is to provide a rotation angle positioning device capable of realizing the correction of a pitch error with a minimum number of correction points.

• eine Drehwinkel-Erfassungsvorrichtung, die einen Erfassungs-Zielring, der an einer Drehwelle vorhanden ist und eine Vielzahl in einem vorgegebenen Abstand ausgebildeter Zähne aufweist,
• sowie einen Winkel-Erfassungssensor aufweist, der so angeordnet ist, dass er den Zähnen zugewandt ist und entsprechend einem Abstand zu den Zähnen einen Ausgang erzeugt, und der einen Drehwinkel des Erfassungs-Zielrings auf Basis des Ausgangs von dem Winkel-Erfassungssensors ermittelt; und eine Drehwellen-Antriebsvorrichtung, die die Drehwelle so dreht, dass der Drehwinkel ein gegebener Befehlswert für den Drehwinkel wird, wobei die Drehwinkel-Positioniervorrichtung enthält:
  • eine Fehlermuster-Speichereinheit, die ein Teilungsperioden-Fehlermuster speichert, das aus Abweichungen zwischen durch den Winkel-Erfassungssensor erfassten Drehwinkeln und Ist-Drehwinkeln besteht, die jeweiligen Korrektur-Unterteilungspunkten einer beliebigen Teilungsperiode in dem Erfassungs-Zielring entsprechen, sowie eine Befehlswert-Korrektureinheit, die den Befehlswert für den Drehwinkel auf Basis des Teilungsperioden-Fehlermusters korrigiert, um einen korrigierten Befehlswert für den Drehwinkel zu ermitteln.

The present invention is a rotary angle positioning device that includes:

• a rotation angle detecting device including a detection target ring provided on a rotating shaft and having a plurality of teeth formed at a predetermined pitch,
• and an angle detection sensor that is arranged to face the teeth and generates an output according to a distance from the teeth, and that detects a rotation angle of the detection target ring based on the output from the angle detection sensor; and a rotating shaft driving device that rotates the rotating shaft so that the rotating angle becomes a given rotating angle command value, wherein the rotating angle positioning device includes:
  • an error pattern storage unit that stores a pitch period error pattern consisting of deviations between rotation angles detected by the angle detection sensor and actual rotation angles corresponding to respective correction dividing points of an arbitrary pitch period in the detection target ring, and a command value correction unit, which corrects the rotation angle command value based on the pitch period error pattern to obtain a corrected rotation angle command value.

The inventors have come to realize that a pitch period error pattern consisting of discrepancies between detected rotation angles and actual rotation angles at points between any two adjacent teeth of the detection target ring has substantially the same tendency in all pitch periods, and have the present invention completed based on this finding.

That is, in the present invention, to correct the command value for the rotation angle, a pitch period error pattern in an arbitrary pitch period is used for all pitch periods, and the rotating shaft is rotationally driven so that the rotation angle detected by the rotation angle detecting device becomes the corrected command value for the Angle of rotation is determined after the correction, whereby an error in the angle of rotation sensor can be compensated.

As described above, since it is possible to perform the correction using only the pitch error pattern consisting of detection errors of the angle detection sensor at correction dividing points between any two adjacent teeth, the number of error correction points can be greatly reduced. and only small storage capacity is required.

In a preferred embodiment of the present invention, the error pattern storage unit stores the pitch period error pattern and a rotation period error pattern consisting of deviations between rotation angles detected by the angle detection sensor and actual rotation angles when the detection target ring rotates once, and the command value Correction unit corrects the rotation angle command value based on the rotation period error pattern and the pitch period error pattern to obtain the corrected rotation angle command value.

According to the preferred embodiment, since the rotation angle command value is corrected based on the pitch period error pattern and the rotation period error pattern, it is possible to eliminate an error due to the deviation of the center of the detection target ring or the like and an error to correct due to machining accuracy of the teeth of the detection target ring or the like.

In another preferred embodiment of the present invention, the command value correction unit corrects the rotation angle command value based on the rotation period error pattern to obtain a first corrected rotation angle command value, and corrects the first corrected rotation angle command value based on the pitch period error pattern. error pattern to determine a second corrected rotation angle command value.

According to the other preferred embodiment, the rotation angle command value is corrected based on the rotation period error pattern, thereby obtaining the first corrected rotation angle command value, and the first corrected rotation angle command value is corrected based on the pitch period error pattern, thereby obtaining the second corrected command value for the rotation angle is obtained, and therefore following the correction of an error due to the deviation of the center of the detection target ring or the the same, the correction of an error due to machining accuracy of the teeth of the detection target ring or the like, thereby making it possible to correct both errors more efficiently and surely.

character list

• 1 12 is a schematic plan view of a machine tool including a rotation angle positioning device according to Embodiment 1 of the present invention;
• 2 Fig. 12 is a schematic of a rotation angle detecting device part of the rotation angle positioning device according to Embodiment 1 of the present invention;
• 3 Fig. 12 is a schematic graphical representation of a rotation period error pattern of the rotation angle positioning device according to Embodiment 1 of the present invention;
• 4 Fig. 12 is a schematic graphical representation of a pitch period error pattern of the rotation angle positioning device according to Embodiment 1 of the present invention.
• 5 Fig. 12 is a schematic diagram used to describe the determination of the pitch period error pattern.
• 6 Fig. 12 is a schematic graphical representation of a concrete example of the spin period error pattern;
• 7 Fig. 12 is a schematic graphical representation of a concrete example of the pitch period error pattern;
• 8th Fig. 14 is a flowchart useful in describing the operation of the rotation angle positioning device according to Embodiment 1 of the present invention;
• 9 Fig. 12 is a schematic diagram useful in describing a dividing period used in the flowchart;
• 10 Fig. 12 is an illustration showing a pitch period error correction table used in the flowchart;
• 11 12 is a diagram showing a rotation period error correction table of a rotation angle positioning device according to an embodiment 2 of the present invention;
• 12 Fig. 14 is a diagram useful in describing a method of detecting a rotation period error of the rotation angle positioning device according to Embodiment 2 of the present invention;
• 13 Fig. 14 is a diagram showing a pitch period error correction table of the rotation angle positioning device according to Embodiment 2 of the present invention; and
• 14 14 is a diagram useful in describing a method of detecting a pitch error of the rotation angle positioning device according to Embodiment 2 of the present invention.

Detailed Description of Preferred Embodiments

Embodiments of the present invention are described below based on the accompanying drawings.

[Embodiment 1]

1 until 10 12 are diagrams useful for describing a rotation angle positioning device of a machine tool according to an embodiment 1 of the present invention.

In the drawings, reference numeral 1 denotes a turret lathe as an example of the machine tool. The turret lathe 1 includes a first headstock 3 arranged at a left end portion of a bed 2, a second headstock 4 arranged to face the first headstock 3, and a tool holder 5 interposed between the first and second heads second headstock 3, 4 and on a rear side thereof.

The second headstock 4 is arranged to be movable in an axial direction (Z-axis direction) with an axis of its second spindle 4a coaxial with an axis of a first spindle 3a of the first headstock 3 . The tool holder 5 has a tool holder base 5a arranged to be movable in a Y-axis direction perpendicular to the Z-axis, and a turret 5b arranged on the tool rest base 5a that it can be rotated about a rotation axis parallel to the Z-axis, and a plurality of tools T are installed on the turret 5b.

The first spindle head 3 comprises a first spindle head body 3b fixed to the bed 2, and the first spindle (rotary shaft) 3a rotatably supported by the first headstock body 3b via a plurality of bearings 3c. Further, a chuck 3e, which receives an object to be machined (workpiece) W, is attached to a front portion 3d of the first spindle 3a protruding toward the second headstock 4 from the first headstock housing 3b.

The second headstock 4 comprises a second headstock housing 4b attached to the bed 2 so that it can be moved in the Z-axis direction, and the second spindle (rotary shaft) 4a supported via a plurality of bearings 4c is rotatably supported by the second headstock housing 4b. Further, a chuck 4e which receives the object to be machined (workpiece) is attached to a front portion 4d of the second spindle 4a protruding toward the first headstock 3 from the second headstock housing 4b.

The first headstock 3 and the second headstock 4 include rotational angle positioning devices 6 which have the same structure. The rotation angle positioning device 6 provided on the first headstock 3 will be described below.

The rotation angle positioning device 6 includes a rotation angle detection device 7 that detects a rotation angle of the first spindle 3a, a drive motor 10 that supports the first spindle 3a so that the rotation angle detected by the rotation angle detection device 7 becomes a given command value α for the rotation angle is, and a control unit 11 which controls the drive by the drive motor 10.

The control unit 11 includes an error pattern storage unit 11a which stores a rotation period error pattern E and a pitch period error pattern F, which will be described later, and a command value correcting unit 11b which calculates the rotation angle command value α based on the rotation period error pattern E is corrected to obtain a first corrected rotation angle command value α1, and corrects the first corrected rotation angle command value α1 based on the pitch period error pattern F to obtain a second corrected rotation angle command value α2.

The driving motor 10 is arranged between the first headstock housing 3b and the first spindle 3a, and its function is to rotationally drive the first spindle 3a at high speed and to rotationally move the first spindle 3a by a small angle.

The rotation angle detection device 7 includes a detection target ring 8 fixed to a rear end portion 3g of the first spindle 3a so as to rotate with the first spindle 3a, and an angle detection sensor 9 fixedly arranged so that it faces the detection target ring 8 in a non-contact manner.

The detection target ring 8 is made of a soft magnetic material in a ring shape, with a plurality (in the present embodiment, 512) teeth 8a formed at a predetermined pitch on its outer peripheral surface.

The angle detection sensor 9 includes a permanent magnet 9b disposed and fixed in a non-magnetic material case 9a so as to face tip faces 8b of the teeth 8a at a right angle, and a Hall IC 9c shown in FIG Case 9a is arranged and fixed so that it is between the permanent magnet 9b and the tip surfaces 8b, and having a plurality of Hall elements 9d. The permanent magnet 9b is arranged so that its north-south pole axis forms a right angle to the tip faces 8b, and the Hall IC 9c is arranged on the north pole side.

The rotation angle detection device 7 of the present embodiment detects the rotation angle of the first spindle 3a with the detection target ring 8 and the angle detection sensor 9. That is, the Angle detection sensor 9 there, as in 2 shown, a voltage signal S corresponding to its distance from a surface of the detection target ring 8 facing it. The magnitude of the voltage signal S is greatest when the angle detection sensor faces a central portion a of the tip faces 8b of the tooth 8a in the direction of rotation, and its value gradually decreases as the position to which the angle detection sensor 9 faces changes from here moves to a middle portion b between the teeth 8a, 8a, and gradually increases as the position to which the angle detecting sensor 9 faces further moves to an adjacent tip face 8b. Therefore, the rotation angle of the first spindle 3a is detected based on the magnitude of the tension signal S from the angle detection sensor 9. FIG.

The first spindle 3a is rotationally driven by the drive motor 10 so as to be positioned so that the rotational angle detected by the rotational angle detecting device 7 becomes a given rotational angle command value α.

In the rotation angle detection device 7 occur in 3 shown rotation period error sometimes due to the deviation of a center position of the detection target ring 8 or the like when the detection target ring 8 rotates once, and in 4 Pitch period errors shown sometimes occur in each pitch period due to machining accuracy of the teeth 8a of the detection target ring 8 or the like.

Therefore, in this embodiment, the rotation angle command value α is corrected based on the rotation period error pattern E, thereby obtaining a first corrected rotation angle command value α1, as will be described later in detail. Then, the first corrected rotation angle command value α1 is corrected on the basis of the pitch period error pattern F, thereby obtaining a second corrected rotation angle command value α2.

Then, the driving motor 10 rotationally drives the first spindle 3a so that the rotational angle detected by the rotational angle detector 7 agrees with the second corrected rotational angle command value α2, thereby rotational angle positioning of the first spindle 3a is performed.

The rotation period error pattern E is determined in the manner described below. First, as in 3 1, correction dividing points 1 to 12 which equally divide one revolution period (360°) of the detection target ring 8 into twelve 30° segments, for example, are determined. As for the rotation angles corresponding to the respective correction dividing points 1 to 12, differences between detected rotation angles measured using the rotation angle sensor 9 actually used and reference rotation angles measured using a high-accuracy sensor that has a sufficiently high resolution. Then, the differences at the correction dividing points 1 to 12 are defined as the rotation period errors E1, E2,...E12, and a curve connecting the rotation period errors E1...E12 is defined as the rotation period error pattern E .

The pitch period error pattern F is found in the following manner. First, when the number of correction subdivisions, as in 5 and 9 shown, is 12 in a pitch period, correction dividing points 1 to 12 are obtained which equally divide an interval between arbitrary teeth 8a to 8a into 12 segments. As for rotation angles corresponding to the respective correction dividing points 1 to 12, deviations between detected rotation angles measured using the angle detection sensor 9 actually used and reference rotation angles measured using the high-accuracy sensor that has a sufficiently high resolution. Then, the differences at the respective correction dividing points 1 to 12 are defined as the pitch period errors F1, F2, ... F12, and a curve connecting the pitch period errors F1 ... F12 is defined as the pitch period error pattern F Are defined.

• Anzahl von Korrektur-Unterteilungspunkten = 512 x 12 = 6144.

It has been found that the pitch period error pattern F has essentially the same tendency in any arbitrary pitch period, as is the case in FIG 4 or 7 is shown. Therefore, in the present embodiment, the pitch period error pattern F is detected in an arbitrary pitch period, and this pattern F is used in all pitch periods. Therefore, regardless of the number of teeth of the detection target ring 8, the number of correction dividing points for the measurement can be as small as 12, and thus can be greatly reduced. If the errors or deviations are determined using the same method as the method for determining the rotation period error pattern E , this results in:

• Number of correction subdivision points = 512 x 12 = 6144.

The rotation period error pattern E and the pitch period error pattern F are stored in the error pattern storage unit 11a of the control unit 11 . The command value correcting unit 11b corrects the rotation angle command value α based on the rotation period error pattern E to obtain the first corrected rotation angle command value α1, and further corrects the first corrected rotation angle command value α1 based on the pitch period error pattern F to find the second corrected rotation angle command value α2.

A method of finding the first corrected rotation angle command value α1 when the rotation angle command value is α will be described with reference to FIG 3 described.

$$\text{E23}=\text{E2}+\left(\text{E3}-\text{E2}\right)\times \left(\mathrm{\alpha }-60°\right)/30°$$

α1 is determined as follows, where E23 is a correction value corresponding to the rotation angle command value α in the rotation period error pattern E. $$\mathrm{a}1=\mathrm{a}+\text{E23}$$

$$\text{E23}=\text{E2}+\left(\text{E3}-\text{E2}\right)\times \left(\mathrm{a}-60°\right)/30°$$

Hereinafter, a method of obtaining the second corrected command value α2 for the rotation angle will be concretely explained based on the flowchart in FIG 8th described. In this case, the rotation angle command value is α, the first corrected rotation angle command value is α1, the second corrected rotation angle command value is α2, the number of teeth of the detection target ring 8 is β (= 512), and the number of divisions in an error correction table (the number of correction division points) is γ (=12).

First, the first corrected rotation angle command value α1, which is the rotation angle command value α corrected by the above-described method, is read (step S1), and it is calculated by (α1/360°) x β (Expression 1), how many teeth 8a of the detection target ring 8 the first corrected rotation angle command value α1 is equivalent to. In this case, the quotient (integral part) of Expression 1 is defined as X, and the fractional part thereof is defined as Y (step 2).

When the fraction (Y) is 0 (step S3), that is, when the first corrected command value α1 for the rotation angle is an angle that coincides with the central portion a of the tip surface 8b of each of the teeth 8a of the detection target ring 8, a correction value read (step S9) corresponding to the division point "0" in the in 10 error correction table shown below, this correction value is added to the first corrected command value α1 for the rotation angle (step S10), and the result of the addition is defined as the final command value for the rotation angle (the second corrected command value α2 for the rotation angle) (step S11) .

On the other hand, when Y is not 0 in step S3, i.e., when the first corrected command value α1 for the rotation angle is an angle corresponding to a point between any adjacent teeth 8a, 8a, first, the adjacent correction dividing points between which the first corrected rotation angle command value α1 is located, and the correction value is calculated from the error correction table based on this position. At this time, when the first corrected command value α1 for the rotation angle agrees with one of the correction dividing points, the correction value corresponding to that dividing point is added to the first corrected command value α1 for the rotation angle as it is.

und das Produkt wird als Z definiert (Schritt S4), und die größte ganze Zahl G, die genauso groß ist wie oder kleiner als das Produkt Z, sowie die kleinste ganze Zahl H, die genau so groß ist wie oder größer als das Produkt Z, werden ermittelt (Schritt S5).That is, it is calculated: $$\text{fraction}\left(\text{Y}\right)\times \text{number of subdivisions}\left(\mathrm{g}\right)$$

and the product is defined as Z (step S4), and the largest integer G that is equal to or smaller than the product Z, and the smallest integer H that is equal to or larger than the product Z , are detected (step S5).

Correction values g, h corresponding to the integers G, H in the error correction table are read (step S6), then (h - g) x (Z - G) is calculated, the product is defined as D (step S7 ), and the sum (g + D) is set as the correction value (step S8).

Then, the sum of the above correction value and the first corrected rotation angle command value α1 becomes the final rotation angle command value (the second corrected rotation angle command value α2) (steps S10, S11).

in Schritt S8 wird g + D = -0,003 + 0,00672 = 0,00372 (°) als der Korrekturwert festgelegt, und der erste korrigierte Befehlswert α1 für den Drehwinkel + 0,00372 (°) wird als der finale Befehlswert für den Drehwinkel festgelegt (der zweite korrigierte Befehlswert α2 für den Drehwinkel).That is, when it is determined in step S2 that the first corrected command value α1 for the rotation angle is equivalent to, for example, 99.32 parts of the teeth of the detection target ring 8, the result in step S4 is Y×γ=0.32×12= 3.84, and the result in step S5 is that the largest integer G equal to or smaller than 3.84 is 3 and the smallest integer H equal to or larger than 3.84, 4, and in step S6, the correction value g corresponding to the dividing point 3 = -0.003 (°) and the correction value h corresponding to the dividing point 4 = 0.005 (°) are read from the error correction table in 10 had read. Thus, the result in step S7 is $$\left(\text{H}-\text{G}\right)\times \left(\text{Z}-\text{G}\right)=\left(0.005-\left(-0.003\right)\right)\times \left(3.84-3\right)=0.00672=\text{D}\text{,}$$

in step S8, g + D = -0.003 + 0.00672 = 0.00372 (°) is set as the correction value, and the first corrected rotation angle command value α1 + 0.00372 (°) is set as the final rotation angle command value (the second corrected command value α2 for the rotation angle).

In the present embodiment, as described above, the rotation angle command value α is corrected based on the rotation period error pattern E, thereby obtaining the first corrected rotation angle command value α1, and the first corrected rotation angle command value α1 is calculated based on the pitch period error pattern F, thereby obtaining the second corrected rotation angle command value α2, thereby making it possible to surely correct an error due to the deviation of the center of the detection target ring 8 or the like and an error due to machining accuracy of the teeth 8a of the detection target ring 8 or the like can be attributed.

Furthermore, the pitch period error pattern F changes due to individual differences of the detection target ring and the angle detection sensor, but it has been found that with the same detection ring, the same angle detection sensor and the same installation conditions, basically the same tendency in each any graduation period exists, and with this note in mind, the in 10 is created based on the pitch period error pattern F in an arbitrary pitch period, and this table is used for the correction in all pitch periods. Therefore, it is possible to greatly reduce the number of correction dividing points, and only a small memory capacity is required.

Further, the rotation angle command value α is corrected based on the rotation period error pattern E, thereby obtaining the first corrected rotation angle command value α1, and the first corrected rotation angle command value α1 is corrected based on the pitch period error pattern F, thereby the second corrected rotation angle command value α2 is obtained. Therefore, correction of an error due to the deviation of the center of the detection target ring or the like is followed by correction of an error due to machining accuracy of the teeth of the detection target ring or the like, thereby making it possible to more efficiently both errors and safer to correct.

[Embodiment 2]

11 until 14 12 are illustrations for use in describing an embodiment 2 of the present invention. In the embodiment 2, the correction of the rotation angle command value α to obtain the first and second corrected rotation angle command values α1, α2 is performed under the condition described below.

1. (1) Der Befehlswort α für den Drehwinkel von 27° wird gelesen.
2. (2) Zunächst wird ein Drehperioden-Fehler berechnet. Ein Drehperioden-Fehlerkorrektur-Punkt C1 = α/B = 27/5 = 5,4 wird ermittelt, wobei sich der Fehlerkorrektur-Punkt C1 zwischen einem Korrektur-Unterteilungspunkt 5 und einem Korrektur-Unterteilungspunkt 6 befindet, und ein Korrekturverhältnis D an dem Korrekturpunkt C1 beträgt D = 0,04.
3. (3) Ein Korrekturmaß Ec1 an dem Fehlerkorrektur-Punkt C1 wird unter Verwendung von Korrekturmaßen E5, E6 an den Korrektur-Unterteilungspunkten 5, 6 in der Drehperioden-Fehlerkorrektur-Tabelle wie folgt berechnet (siehe 12). $$\text{Ec1}=\text{E5}+\left(\text{E6}-\text{E5}\right)\times \text{D}$$
   

The rotation angle command value α is 27°, an interval B between correction dividing points in one rotation period is 5°, and a rotation period error correction table (rotation period error pattern E) shown in FIG 11 shown is created. The number of teeth of the detection target ring is 512, the number of correction dividing points γ in one pitch period is 16, and a pitch period error correction table (pitch period error pattern F) shown in FIG 12 shown is created. At this time, the rotation angle command value α is set in consideration of necessary corrections such as backlash correction, thermal expansion correction, and the like.

1. (1) The command word α for the rotation angle of 27° is read.
2. (2) First, a rotation period error is calculated. A rotational period error correction point C1 = α/B = 27/5 = 5.4 is found, the error correction point C1 being between a correction dividing point 5 and a correction dividing point 6, and a correction ratio D at the correction point C1 is D=0.04.
3. (3) A correction amount Ec1 at the error correction point C1 is calculated using correction amounts E5, E6 at the correction dividing points 5, 6 in the rotation period error correction table as follows (see 12 ). $$\text{Ec1}=\text{E5}+\left(\text{E6}-\text{E5}\right)\times \text{D}$$
   

• (4) Daher gilt für den ersten korrigierten Befehlswert α1 für den Drehwinkel: α + Ec1 = 27,0038°
• (5) Anschließend wird der Teilungsperioden-Fehler berechnet. Für einen Teilungsperioden-Fehlerkorrektur-Punkt gilt: $$\text{C2}=\mathrm{<figure-callout\; id="1"\; label="\alpha "\; filenames="DE102011076263B4\_0016.png,DE102011076263B4\_0017.png"\; state="\{\{state\}\}">\alpha </figure-callout>}1/\left(360\text{/Anzahl der Z}\ddot{\text{a}}\text{hne}\right)=\mathrm{27,0038}\text{/}\left(360\text{/512}\right)=\mathrm{38,4054044...,}$$
  
  und daher befindet sich der Teilungsperioden-Fehlerkorrektur-Punkt C2 zwischen dem 38. und dem 39. Zahn des Erfassungs-Zielrings.
• (6) Des Weiteren gilt für die Anzahl von Unterteilungen: 16 x 0,405 ... = 6,4864 ..., und daher befindet sich der Korrekturpunkt C2 zwischen dem Korrektur-Unterteilungspunkt 6 und dem Korrektur-Unterteilungspunkt 7, und für ein Teilungs-Korrekturunterteilungsverhältnis gilt: N = 0,4864 ...
• (7) Ein Korrekturmaß Fc2 an dem Teilungsperioden-Korrekturpunkt C2 wird wie im Folgenden dargestellt, unter Verwendung von Korrekturmaßen F6, F7 an den Korrektur-Unterteilungspunkten 6, 7 in der Teilungsperioden-Fehlerkorrektur-Tabelle (siehe 14) berechnet: $$\text{Fc2}=\text{F6}+\left(\text{F7}-\text{F6}\right)\times \text{N}$$
  

How from the in 11 As can be seen from the rotation period error correction table shown, E 5 = 0.003° and E6 = 0.005° and therefore $$\text{Ec1}=0.003+0.002\times 0.4=0.0038$$

• (4) Therefore, for the first corrected rotation angle command value α1, α + Ec1 = 27.0038°
• (5) Then the pitch error is calculated. For a division period error correction point: $$\text{C2}=\mathrm{a}1/\left(360\text{/number of Z}\ddot{\text{a}}\text{without}\right)=27.0038\text{/}\left(360\text{/512}\right)=\mathrm{38.4054044...,}$$
  
  and therefore the pitch period error correction point C2 is between the 38th and 39th teeth of the detection target ring.
• (6) Furthermore, for the number of divisions: 16 x 0.405 ... = 6.4864 ... and therefore the correction point C2 is between the correction division point 6 and the correction division point 7, and for one division - Correction subdivision ratio applies: N = 0.4864 ...
• (7) A correction amount Fc2 at the pitch period correction point C2 is set as follows, using correction amounts F6, F7 at the correction dividing points 6, 7 in the pitch period error correction table (see 14 ) calculated: $$\text{Fc2}=\text{F6}+\left(\text{F7}-\text{F6}\right)\times \text{N}$$
  

und daher $$\text{Fc2}=-\mathrm{0,001}+\left(-\mathrm{0,004}+\mathrm{0,001}\right)\times \mathrm{0,4864}\dots =-\mathrm{0,0024594}\dots$$

• (8) Daher gilt für den zweiten korrigierten Befehlswert α2 für den Drehwinkel: $$\mathrm{<figure-callout\; id="1"\; label="\alpha "\; filenames="DE102011076263B4\_0016.png,DE102011076263B4\_0017.png"\; state="\{\{state\}\}">\alpha </figure-callout>}1+\text{Fc2}=\mathrm{27,0038}-\mathrm{0,0024594..}=\mathrm{27,0013405..}°$$
  

How from the in 13 shown in the scale period error correction table, the following applies: $$\text{F6}=-0.001°\text{and F7}=-0.004°$$

and therefore $$\text{Fc2}=-0.001+\left(-0.004+0.001\right)\times 0.4864...=-0.0024594...$$

• (8) Therefore, for the second corrected rotation angle command value α2: $$\mathrm{a}1+\text{Fc2}=27.0038-\mathrm{0.0024594..}=\mathrm{27.0013405..}°$$
  

In embodiment 2, the same effects as in embodiment 1 are obtained.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing specification, and all changes which come within the meaning and range of equivalence of the claims are therefore to be considered as included therein.

Claims (3)

Angle of rotation positioning device (6) containing: a rotation angle detecting device (7) having a detection target ring (8) provided on a rotating shaft (3a) and having a plurality of teeth (8a) formed at a predetermined pitch, and an angle detecting sensor (9), which is arranged to face the teeth (8a) and generates an output corresponding to a distance from the teeth (8a), and which detects a rotation angle of the detection target ring (8) based on the output from the angle detection sensor (9 ) determined; and a rotating shaft driving device (10) rotating the rotating shaft (3a) so that the rotating angle becomes a given command value (α) for the rotating angle, the rotating angle positioning device (6) comprising: an error pattern storage unit (11a) storing a pitch period error pattern (F) consisting of deviations between rotation angles detected by the angle detection sensor (9) and actual rotation angles, the respective correction dividing points of an arbitrary pitch period in the detection target ring (8) accordingly, and a command value correcting unit (11b) which corrects the command value (α) for the rotation angle based on the pitch period error pattern (F) to obtain a corrected command value (α2) for the rotation angle. Angle of rotation positioning device (6). claim 1 , wherein: the error pattern storage unit (11a) stores the pitch period error pattern (F) and a rotation period error pattern (E) resulting from deviations between rotation angles detected by the angle detection sensor (9) and actual rotation angles when the detection is rotated once - target ring (8); and the command value correction unit (11b) corrects the rotation angle command value (α) based on the rotation period error pattern (E) and the pitch period error pattern (F) to obtain the corrected rotation angle command value (α2). Angle of rotation positioning device (6). claim 2 , wherein the command value correcting unit (11b) corrects the command value (α) for the rotation angle based on the rotation period error pattern (E) to obtain a first corrected command value (α1) for the rotation angle, and the first corrected command value (α1) is corrected for the rotation angle based on the pitch period error pattern (F) to obtain a second corrected command value (α2) for the rotation angle.

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