DE102018131708A1 - Sensor unit and method for detecting an angular position of a rotating component - Google Patents

Abstract

The invention relates to a method for detecting an angular position (ω) of a rotary component by a sensor unit (10), comprising a sensor element (20) with a transmission element that emits a sensor signal (22) and a receiving element that receives the sensor signal (22), a first reflection element (12) connected to the rotating component and rotatable about an axis of rotation, which reflects the sensor signal (22), and the receiving element receives the reflected sensor signal (22), the transit time of the sensor signal (22) as a measurement signal (Y, 112 ) is detected and the first reflection element (12) causes a measurement distance which is variable as a function of the rotation about the axis of rotation and which is run through by the sensor signal (22), and thus causes a periodic change in the measurement signal (Y, 112), with the rotating component altogether n the rotation axis rotatable and each fixedly arranged reflection elements (12, 14, 16, 18, 26) are connected, each ils reflect the sensor signal (22) and the receiving element receives these respectively reflected sensor signals (22), the respective transit time of the sensor signal (22) being the first associated with the respective first to nth reflection element (12, 14, 16, 18, 26) to nth measurement signal (Y, 112, 114, 116, 118, 126) is detected and the n measurement signals (Y, 112, 114, 116, 118, 126) are mutually displaced by the offset angle (α), the number n ≥ 3 and an angular position (ω) of the rotary component depending on a measurement signal (Y, 112, 114, 116, 118, 126) of one of the reflection elements i ∈ n (12, 14, 16, 18, 26), a measurement signal ( Y) of the adjacent reflection element i - 1 and a measurement signal (Y) of the adjacent reflection element i + 1 is determined. The invention also relates to a sensor unit (10) for determining an angular position of a rotary component in which such a method is used.

Description

The invention relates to a method for detecting an angular position of a rotary component according to the preamble of claim 1. Furthermore, the invention relates to a sensor unit in which such a method is used.

A sensor unit for detecting an angular position of a rotary component is, for example, in DE 10 2018 124 232.8 described. It describes a sensor unit with a sensor element that emits a measurement signal and a receiving element that receives the measurement signal, and a reflection element that rotates about an axis of rotation with the rotary component and reflects the measurement signal. The transit time of the measurement signal is dependent on a measurement distance between the reflection element designed as a wedge disk and the sensor element.

The object of the present invention is to improve a method for detecting an angular position of a rotary component. Furthermore, a sensor unit for detecting an angular position of a rotary component is to be improved. The measuring accuracy for detecting the angular position should be increased. Furthermore, the reliability of the detection should be increased.

At least one of these tasks is solved by a method with the features of claim 1. Accordingly, a method for detecting an angular position of a rotating component by a sensor unit is proposed, comprising a sensor element with a transmitting element that emits a sensor signal and a receiving element that receives the sensor signal, a first reflection element that is connected to the rotating component and rotatable about an axis of rotation the sensor signal reflects, and the receiving element receives the reflected sensor signal, the transit time of the sensor signal being recorded as a measurement signal and the first reflection element causing a measurement distance which is variable as a function of the rotation about the axis of rotation and which the sensor signal traverses and thus causes a periodic change in the measurement signal, whereby with the rotary component a total of n reflection elements which are rotatable and rotated about the axis of rotation are connected, each reflecting the sensor signal and the receiving element receiving these respectively reflected sensor signals, w The respective transit time of the sensor signal is detected as the first to nth measurement signal assigned to the respective first to nth reflection element and the n measurement signals are mutually displaced by the offset angle, the number n ≥ 3 and an angular position of the rotary component depending on one Measurement signal of one of the reflection elements i ∈ n, a measurement signal of the on the one hand adjacent reflection element i-1 and a measurement signal of the on the other hand adjacent reflection element i + 1 is determined.

This enables a reliable detection of the angular position of the rotating component. The measurement accuracy can be improved and the susceptibility to external interference can be reduced. Furthermore, an unbalance of the sensor unit, in particular of the reflection element, can be reduced by using a plurality of reflection elements.

The sensor element can be arranged radially spaced from the axis of rotation. A so-called off-axis measurement can be made possible. The sensor element can be an ultrasonic sensor, comprising an ultrasonic transmitter as a transmitting element and an ultrasonic receiver as a receiving element. The ultrasonic sensor can be an ultrasonic transducer. The ultrasound transmitter and the ultrasound receiver can be formed by a single ultrasound transducer. The ultrasonic sensor can include an ultrasonic measuring head with an ultrasonic transducer and control electronics. The ultrasound sensor can comprise an ultrasound array.

The sensor signal can be an acoustic or an electromagnetic signal.

Two sensor elements, which are arranged offset on the circumferential side about the axis of rotation with respect to the reflection element, can be provided. The two sensor elements can be arranged offset by 90 °.

A measuring distance between the surface of the reflection element that faces the sensor element and the sensor element can be variable depending on an angular position of the reflection element with respect to the axis of rotation. The smaller the measuring distance, the shorter the running time of the sensor signal.

An angular position of the reflection element can be concluded from the transit time of the sensor signal, which is correlated with the change in the measuring distance. The circumference of the measurement distance can change constantly between a minimum and a maximum measurement distance by a wedge angle implemented on the reflection element. The minimum and the maximum measuring distance with respect to the reflection element are preferably offset by 180 °. The respective reflection element can be a wedge disk.

In a preferred embodiment of the invention, the respective reflection element is connected in a rotationally fixed manner to the rotary component or in one piece with the Swivel component executed. The axis of rotation of the reflection element and an axis of rotation of the rotary component can be concentric.

In a special embodiment of the invention, the reflection elements are arranged rotated by the offset angle. The offset angle can be constant across the n reflection elements and fixed by 360 ° / n.

In a particularly preferred embodiment of the invention, the measurement signal of the ith reflection element is described by a linear approximation between an intersection of the ith measurement signal with another measurement signal and a further intersection of the ith measurement signal with another measurement signal.

In a special embodiment of the invention, the linear approximation is carried out in a measurement range which excludes the maximum and minimum of the i-th measurement signal. The measuring range can also exclude the maximum and the minimum of the adjacent measuring signals i-1 and i + 1.

In a further special embodiment of the invention, the linear approximation is divided into several angular ranges with a straight line assigned to each angular range, and the number of angular ranges over a full period of the i-th measurement signal is 2 * n.

In a special embodiment of the invention, an assignment table can be used to determine the angular range in which the measurement signal to be used for determining the angular position via the linear approximation lies.

In a particularly preferred embodiment of the invention, in addition to the i-th measurement signal, a measurement signal i + 1 (Y _{i + 1} ) following this and a measurement signal i-1 (Y _i-1 ) preceding this is recorded and the angular position as a function thereof ω determined.

The measurement signal Y _{i of} the i-th reflection element can be via the angle of rotation φ be described as follows $$Y_i=cOs\left(\phi +{\phi }_0\right)$$

und das Messsignal Y_i-1 des vorausgehenden Reflektionselements i-1 kann wie folgt beschrieben werden $$Y_{i-1}=cos\left(\phi -\alpha +{\phi }_0\right)$$

The measurement signal Y _{i + of} the subsequent reflection element i + 1 can be described as follows $$Y_{i+1}=cOs\left(\phi +\alpha +{\phi }_0\right)$$

and the measurement signal Y _{i-1 of} the preceding reflection element i-1 can be described as follows $$Y_{i-1}=cOs\left(\phi -\alpha +{\phi }_0\right)$$

The measurement signal Y _{i + 1} is compared to the measurement signal Y _i by the offset angle α and that the measurement signal Y _i-1 is shifted relative to the measurement signal Y _i by the offset angle -α, the offset angle α as follows from the number of measurement signals n depends $$\alpha =\frac{\mathrm{2nd}\pi }{n}$$

und kann nachfolgend vereinfacht werden zu $$Y_{i+1}-Y_{i-1}=-2sin\left(\phi +{\phi }_0\right)-sin\alpha$$

In a preferred embodiment of the invention, the angular position ω determined depending on a difference between the measurement signals i + 1 (Y _{i- +} ) and i-1 (Y _{i + 1} ). The angular position of the rotary component can be determined on the basis of the measurement signal i as a function of a difference between the measurement signals i-1 and i + 1 as described below. The measurement signal difference is included $$Y_{i+1}-Y_{i-1}=cOs\left(\phi +\alpha +{\phi }_0\right)-cOs\left(\phi -\alpha +{\phi }_0\right)$$

and can be simplified below $$Y_{i+1}-Y_{i-1}=-\mathrm{2nd}sin\left(\phi +{\phi }_0\right)-sin\alpha$$

wie folgt umschrieben werden $$Y_i^{\text{'}}=sin\left(\phi +{\phi }_0\right)=\frac{Y_{i-1}-Y_{i+1}}{2\cdot sin\alpha }$$

The i-th measurement signal Y _i can thus be $Y_i^{\text{'}}$

can be described as follows $$Y_i^{\text{'}}=sin\left(\phi +{\phi }_0\right)=\frac{Y_{i-1}-Y_{i+1}}{\mathrm{2nd}\cdot sin\alpha }$$

Sinα is a constant that depends on the number of measurement signals according to (4).

All measurement signals Y _i with i = 1 ... n are measured and described via (1). The respective measurement signals are then transformed via (7). These two representations are then used as follows to determine the angular position ω _{i of} the rotary component, based in each case on the i-th measurement signal $${\omega }_i=\phi +{\mathrm{<figure-callout\; id="0"\; label="\phi "\; filenames="DE102018131708A1\_0018.png,DE102018131708A1\_0019.png"\; state="\{\{state\}\}">\phi </figure-callout>}}_0=atan\mathrm{2nd}\left(Y_i,\frac{Y_{i-1}-Y_{i+1}}{\mathrm{2nd}\cdot sin\alpha }\right)$$

gültig für eine gerade Anzahl n an Messsignalen und $${\omega }_i=\frac{{\displaystyle {\sum }_{i=1}^n{\omega }_i}}{n}\pm \frac{\alpha }{2}$$

gültig für eine ungerade Anzahl n an Messsignalen. Durch das Datenfusionsverfahren können auftretende Fehler, beispielsweise eine Sensorrauschen oder Toleranzfehler, bei der Erfassung der Winkelposition des Drehbauteils verringert werden.In a subsequent data fusion method, the angular positions ω _i determined based on each measurement signal i can be related to the angular position of the rotary component as follows ω be brought together $$\omega =\frac{{\displaystyle {\sum }_{i=1}^n{\omega }_i}}{n}$$

valid for an even number n on measurement signals and $${\omega }_i=\frac{{\displaystyle {\sum }_{i=1}^n{\omega }_i}}{n}\pm \frac{\alpha }{\mathrm{2nd}}$$

valid for an odd number n on measurement signals. The data fusion method can be used to reduce errors that occur, for example sensor noise or tolerance errors, in the detection of the angular position of the rotary component.

Furthermore, at least one of the aforementioned tasks is solved by a sensor unit for detecting an angular position of a rotating component, comprising a sensor element with a transmitting element that transmits a sensor signal and a receiving element that receives the sensor signal, a sensor element that is connected to the rotating component and rotatable about an axis of rotation first reflection element, which reflects the sensor signal, and the receiving element receives the reflected sensor signal, the transit time of the sensor signal being recorded as a measurement signal, and the first reflection element having a measurement distance which is variable as a function of the rotation about the axis of rotation and which the sensor signal traverses, and thus a periodic change in the Measurement signal causes, wherein the detection of the angular position of the reflection element is carried out by a method with at least one of the features previously specified in this regard.

As a result, the measurement accuracy and the reliability of the sensor unit can be improved.

Furthermore, an electric motor is proposed, comprising a stator and a rotatable rotor and a sensor unit described above, the rotor comprising the rotary component or being designed as a rotary component. This can increase engine efficiency and performance. The electric motor can be installed in a clutch actuator for automated clutch actuation

Further advantages and advantageous embodiments of the invention result from the description of the figures and the figures.

• 1: Eine räumliche Ansicht einer Sensoreinheit in einer speziellen Ausführungsform der Erfindung.
• 2: Messsignale der Sensoreinheit aus 1.
• 3: Eine räumliche Ansicht einer Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.
• 4: Messsignale der Sensoreinheit aus 3.
• 5: Eine räumliche Ansicht einer Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.
• 6: Messsignale der Sensoreinheit aus 5.
• 7: Messsignal einer Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.
• 8: Messsignale einer Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.
• 9: Messsignale und Zuordnungstabelle einer Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.
• 10: Messsignale einer Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.
• 11: Messsignale einer Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.
• 12: Winkelfehlerdiagramm einer Sensoreinheit in einer weiteren speziellen Ausführungsformen der Erfindung.
• 13: Einflüsse von Nichtlinearitäten dritter Ordnung auf eine Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.
• 14: Winkelfehlerdiagramm einer Sensoreinheit in einer weiteren speziellen Ausführungsform der Erfindung.

The invention is described in detail below with reference to the figures. They show in detail:

• 1 : A spatial view of a sensor unit in a special embodiment of the invention.
• 2nd : Measurement signals from the sensor unit off 1 .
• 3rd : A spatial view of a sensor unit in a further special embodiment of the invention.
• 4th : Measurement signals from the sensor unit off 3rd .
• 5 : A spatial view of a sensor unit in a further special embodiment of the invention.
• 6 : Measurement signals from the sensor unit off 5 .
• 7 Measurement signal of a sensor unit in a further special embodiment of the invention.
• 8th Measurement signals of a sensor unit in a further special embodiment of the invention.
• 9 : Measurement signals and assignment table of a sensor unit in a further special embodiment of the invention.
• 10th Measurement signals of a sensor unit in a further special embodiment of the invention.
• 11 Measurement signals of a sensor unit in a further special embodiment of the invention.
• 12 : Angle error diagram of a sensor unit in a further special embodiment of the invention.
• 13 : Influences of third-order nonlinearities on a sensor unit in a further special embodiment of the invention.
• 14 : Angle error diagram of a sensor unit in a further special embodiment of the invention.

1 shows a spatial view of a sensor unit 10th in a special embodiment of the invention. The sensor unit 10th is used to detect an angular position of a rotating component. The rotating component is not shown here, but is with a first reflection element 12 non-rotatably connected and rotatable about an axis of rotation. The first reflection element 12 is rotatable about an axis of rotation which is concentric with the axis of rotation of the rotary component.

In addition to the first reflection element 12 are concentric to this and each concentric to each other a second reflection element 14 , a third reflection element 16 and a fourth Reflection element 18th arranged and each rotatably connected to the rotary member. An outer diameter of the second reflection element 14 is smaller than an inner diameter of the first reflection element 12 . An outside diameter of the third reflection element 16 is smaller than an inner diameter of the second reflection element 14 . The outside diameter of the fourth reflection element 18th is smaller than an inner diameter of the third reflection element 16 .

The sensor element 20th can be designed as an ultrasound array and has a transmission element which receives a sensor signal 22 sends out and a receiving element, which the sensor signal 22 receives on. The transmitting element and receiving element can represent the same component in that the ultrasound array changes, for example, between a transmitting function and a receiving function. The first reflection element rotatable about an axis of rotation 12 reflects that from the sensor element 20th emitted sensor signal 22 . The receiving element of the sensor element 20th captures the term of the first reflection element 12 reflected sensor signal 22 as the first measurement signal.

The runtime of the sensor signal 22 is from a measuring distance between the surface 24th of the first reflection element 12 that the sensor element 20th is facing and the sensor element 20th dependent. The measuring distance in turn is from an angular position of the first reflection element 12 dependent and changeable with respect to the axis of rotation. The smaller the measuring distance, the shorter the running time of the sensor signal 22 . Via the running time of the sensor signal correlated with a change in the measuring distance 22 can on an angular position of the first reflection element 12 getting closed. The measurement distance can be constant on the circumference between a minimum and a maximum measurement distance by one at the first reflection element 12 change the wedge angle. The minimum and maximum measuring distance in relation to the first reflection element 12 are preferably offset by 180 °.

The first, second, third and fourth reflection element 12 , 14 , 16 , 18th are rotatably connected to each other and designed as wedge washers. The second reflection element 14 is opposite the first reflection element 12 offset by 90 °. The third reflection element 16 is opposite the second reflection element 14 offset by 90 ° and in relation to the first reflection element 12 offset by 180 °. The fourth reflection element 18th is opposite the third reflection element 16 offset by 90 ° and opposite the second reflection element 14 offset by 180 ° and 270 ° with respect to the first reflection element.

The reflection elements, which are rotated relative to each other by the offset angle of 90 ° 12 , 14 , 16 , 18th each reflect that from the sensor element 20th emitted sensor signal 22 . The receiving element receives the respectively reflected sensor signals 22 and then the transit time of the respective sensor signal as the respective reflection element 12 , 14 , 16 , 18th assigned measurement signal.

The composite of the first, second, third and fourth reflection element 12 , 14 , 16 , 18th is balanced with each other by the staggered arrangement and thereby reduces stress on the rotary component.

In 2nd are measurement signals from the sensor unit 1 shown. The measurement signals reflect the transit time of the respective sensor signal depending on the angular position. The first measurement signal 112 is the first reflection element, the second measurement signal 114 is the second reflection element, the third measurement signal 116 is the third reflection element and the fourth measurement signal 118 is the measurement signal assigned to the fourth reflection element. The measurement signals 112 , 114 , 116 , 118 are also shifted by an angle of 90 ° to each other in accordance with the offset angle between the individual reflection elements of 90 °. The measurement signals 112 , 114 , 116 , 118 are dependent on the measuring distance between the respective reflection element and the sensor element and run periodically over the angle and can be described using an angle function.

3rd shows a spatial view of a sensor unit 10th in a further special embodiment of the invention. The sensor unit 10th has a first reflection element 12 , a second reflection element arranged concentrically to this and offset by 120 ° 14 and a concentric with the first and second reflecting elements 12 , 14 and offset by 120 ° to the second reflection element 14 arranged third reflection element 16 on.

The first, second and third reflection element 12 , 14 , 16 can do that from the sensor element 20th the sensor unit 10th outgoing sensor signal and reflect the sensor element 20th receives the respective reflected sensor signals. Their runtime is used as the respective measurement signal, as in 4th shown, recorded. The first reflection element 12 is the first measurement signal 112 , the second reflection element 14 is the second measurement signal 114 and the third reflection element 16 is the third measurement signal 116 assigned. The first, second and third measurement signal 112 , 114 , 116 are mutually displaced by 120 °.

With an arrangement of three reflection elements, the costs of a sensor unit can be reduced compared to a sensor unit with four reflection elements. However, a sensor unit with four reflection elements can be better balanced than a sensor unit with only three reflection elements.

An even better balance is achieved by the in 5 shown arrangement of a sensor unit 10th achieved in a further special embodiment of the invention. A total of five reflection elements are used, which allows a good distribution and a better compensation of the unbalance.

The sensor unit 10th has a first reflection element 12 , a second reflection element arranged concentrically to this and offset by 90 ° 14 , a concentric to the first and second reflecting element 12 , 14 and offset by 72 ° to the second reflection element 14 arranged third reflection element 16 , one to the third reflection element 14 fourth reflection element offset by 72 ° 18th and one opposite to the fourth reflection element 18th fifth reflection element offset by 72 ° 26 on.

The reflection elements 12 , 14 , 16 , 18th , 26 can do that from the sensor element 20th the sensor unit 10th outgoing sensor signal and reflect the sensor element 20th receives the respective sensor signals. The measurement signals corresponding to the transit time of the respective sensor signals are shown in 6 shown. The first reflection element 12 is the first measurement signal 112 , the second reflection element 14 is the second measurement signal 114 , the third reflection element 16 is the third measurement signal 116 , the fourth reflection element 18th is the fourth measurement signal 114 and the fifth reflection element 26 is the fifth measurement signal 126 assigned. The first, second, third, fourth and fifth measurement signal 112 , 114 , 116 , 118 , 126 are mutually shifted by 72 °.

7 shows a measurement signal of a sensor unit in a further special embodiment of the invention. The measurement signal that runs periodically over the angle and can be represented by an angle function 28 is in several angular ranges 30th assigned. In every angular range 30th becomes the measurement signal 28 a linear approximation 32 based on a respective straight line 34 assigned.

In one the maximum and the minimum of the measurement signal 28 excluding measuring range 36 is by linear approximation 32 an approximation to the actual measurement signal 28 with a smaller deviation than possible in the remaining, excluded area.

The linear approximation 32 can like in 8th shown, the measurement signals of a sensor unit in a further special embodiment of the invention, are used to determine the angular position of the rotary component. An angular position of the rotary component is determined by using five reflection elements, each of which has a first, second, third, fourth and fifth measurement signal 112 , 14 , 116 , 118 , 126 trigger, determined. In a measuring range that excludes the maximum and minimum of all measuring signals 36 is between two intersections 40 of the measurement signals 112 , 114 , 116 , 118 , 126 a linear approximation 32 carried out. The respective measurement signals 112 , 114 , 116 , 118 , 126 consist of several measured values, which are recorded, for example, by using a sampling rate of the sensor element.

The linear approximation 32 in the measuring range 36 enables the periodically running measurement signal to be mapped in the measurement range 36 through respective straight lines 34 , which in turn determines the angular position of the measured value 44 assigned reflection elements and thus the angular position of the rotary component is determined.

The cutout A illustrates the existing, albeit minor, deviation 46 between the actually measured measurement signal 114 and the linear approximation 32 .

9 shows measurement signals and an assignment table 48 a sensor unit in a further special embodiment of the invention. A total of n = 5 reflection elements which are rotatable about the axis of rotation and are arranged at a respective offset angle, here by 72 °, are rotatably connected to the rotating component. The five reflection elements each reflect the sensor signal and the transit time of the n = 5 reflected sensor signals is in each case as the first to nth measurement signal assigned to the respective first to nth reflection element 112 , 114 , 116 , 118 , 126 recorded, which also each other by the respective offset angle α are moved.

The offset angle α the measurement signals are constant across the n reflection elements and fixed by 360 ° / n, here with n = 5 corresponding to 72 °. An angular position of the rotary component is dependent on a measured value of one of the reflection elements i ∈ n, here on a measured value of the first measurement signal 112 , a measured value of the on the one hand adjacent reflection element i - 1, here a measured value of the third measurement signal 116 and a measured value of the reflection element i + 1, which is adjacent on the other hand, here a measured value of the fourth measurement signal 118 , determined. The measurement signal of the i-th reflection element, here the measurement signal 112 is done by a linear approximation 32 between one Intersection 40 of the i-th measurement signal generated by the i-th reflection element, here the first measurement signal 112 , with the third measurement signal 116 and the fourth measurement signal 118 pictured. With linear approximation 32 becomes a straight line 34 educated. The linear approximation 32 takes place in a the maximum and minimum of the first measurement signal 112 excluding measuring range 36 by an upper limit B and a lower limit -B of the amplitude is spanned.

An angular position assumed here as an example ω corresponding measured value of the rotating component 52 here is one of the linear approximation 32 of the first measurement signal 112 assigned measured value. However, the one from this angular position ω deviating first angular position also corresponds to the linear approximation of one of the n-1 further measurement signals 114 , 116 , 118 , 126 be assigned, depending on which angle the angular position ω corresponds to the rotating component.

To be able to classify which of the linear approximations 32 of the n measurement signals 112 , 114 , 116 , 118 , 126 to determine the angular position is the full period of the first measurement signal 112 in several angular ranges 30th with any angular range 30th assigned straight lines 34 divided, the number of angular ranges 30th is equal to 2 · n, here corresponding to ten. Determining which of the angular ranges 30th when determining the respective angular position ω over that in every angular range 30th linear approximation 32 is to be used via the assignment table 48 met. The mapping table 48 gives for the five measurement signals S1 to S5 , according to the measurement signals 112 , 114 , 116 , 118 , 126 the respective conditions that the measurement signals S1 to S5 must meet in order to determine the angular range to be used for determining the angular position 30th to be able to assign.

mit dem bekannten, den Anfang des betreffenden Winkelbereichs 30 angebenden Startwinkel α₀ .In the example of the measured value shown here 52 , the angular range encompassing this was selected because the fifth measurement signal S5 as below the lower limit -B, the second measurement signal 114 and the third measurement signal 116 than above the upper limit B lying and the fourth measurement signal was measured as being below the lower limit -B. This is the first measurement signal 112 in this angular range 30th the selected one where the linear approximation 32 Using the following relationship, which generally applies to all angular ranges, for determining the angular position ω of the rotating component is carried out $$\omega ={\mathrm{<figure-callout\; id="0"\; label="\alpha "\; filenames="DE102018131708A1\_0018.png,DE102018131708A1\_0019.png"\; state="\{\{state\}\}">\alpha </figure-callout>}}_0+\frac{A}{B}\cdot \frac{180}{n}$$

with the known, the beginning of the angular range in question 30th specified starting angle α ₀ .

Through the assignment table 48 the measurement value always becomes from the n measurement signals A of the measurement signal to determine the angular position according to ( 11 ) selected in the angular range as the measured value A assigned measurement signal is specified, the angular range being specified via the queried conditions of the remaining measurement signals. The respectively selected and the measured value A specified measuring signals pass through in the associated measuring range 30th all the zero crossing.

The angular position ω of the rotating component is determined by the starting angle, which in the example of the measured value lying here 52 Is 180 °, the amount of the limit B , here for example 0.3 and the number n on measurement signals via ( 11 ) depending on the measured value A determined. This enables a reliable and precise determination of an angular position of the rotary component.

The selected over the angular range and the measured value A measuring signals are an even number n on measurement signals in the positive range as in 10th shown in which a first, second, third and fourth measurement signal 112 , 114 , 116 , 118 be used. If the number is odd n the selected and the measured value pass through the measurement signals A measuring signals forming the zero crossing, as in 11 with five measurement signals 112 , 114 , 116 , 118 , 126 shown.

In 12 An angular error diagram of a sensor unit is shown in a further special embodiment of the invention. The angular error increases with an increasing number of measurement signals y than the deviation between the linear approximation and the actual measured values. The angle error depends y with the same number of measurement signals, it depends on whether the number of measurement signals is as determined by the course 128 illustrates straight or as in the course 130 is odd. This is also due to that in the 10th and 11 in relation to the periodic angular function linear approximation, which is in the positive range with an even number of measurement signals, on the other hand passes through the zero crossing with an odd number.

The angular error y (n) can be an odd number n on measurement signals are expressed as follows $$y\left(n\ge \mathrm{3rd}\right)={\left(\frac{2.45}{n}\right)}^{\mathrm{3rd}}$$

The angular error y (n) can with an even number n on measurement signals are expressed as follows $$y\left(n\ge \mathrm{3rd}\right)={\left(\frac{\mathrm{2nd}\cdot 2.45}{n}\right)}^{\mathrm{3rd}}$$

und deren Einfluss für verschiedene Nichtlinearitätsparameter c 13 zeigt.The linear approximation of the measurement signals is susceptible to non-linearities in the measurement signals. A typical non-linearity is the third order in the measurement signal s, which is dependent on the angular position ω is described by the following context $$s=cOs\left(\omega \right)+c\cdot cOs\left(\mathrm{3rd}\omega \right)$$

and their influence for various non-linearity parameters c 13 shows.

Further x-order nonlinearities can also occur, with which the following relationship exists $$s=cOs\left(\omega \right)+c\cdot cOs\left(x\omega \right)$$

mit der Systemkonstanten a, die wiederum von der Anzahl der Messsignale abhängt. Ist der Winkelfehler y bei Durchführung des Verfahrens zur Ermittlung der Winkelposition zu hoch, kann die Anzahl an Messsignalen erhöht werden, bis die erforderliche Genauigkeit der linearen Approximation erreicht wird.In 14 An angular error diagram of a sensor unit is shown in a further special embodiment of the invention. The angular error y depends on the non-linearity parameter c as follows $$y=a\cdot \left(1-\frac{1}{c+1}\right)$$

with the system constant a , which in turn depends on the number of measurement signals. Is the angular error y If the method for determining the angular position is carried out too high, the number of measurement signals can be increased until the required accuracy of the linear approximation is achieved.

Reference symbol list

10th

Sensor unit

12

first reflection element

14

second reflection element

16

third reflection element

18th

fourth reflection element

20th

Sensor element

22

Sensor signal

24th

surface

26

fifth reflection element

28

Measurement signal

30th

Angular range

32

linear approximation

34

Straight

36

Measuring range

40

Intersection

42

Measured value gradient

44

Reading

46

deviation

48

Mapping table

50

Measured value gradient

52, A.

Reading

112, S1

first measurement signal

114, S2

second measurement signal

116, S3

third measurement signal

118, S4

fourth measurement signal

126, S5

fifth measurement signal

128

course

130

course

α ₀

Starting angle

α

Offset angle

A

Reading

a

System constant

B

limit

c

Non-linearity parameters

φ

Angle of rotation

n

Number of measurement signals

ω

Angular position

y

Angular error

Y

Measurement signal

QUOTES INCLUDE IN THE DESCRIPTION

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Patent literature cited

• DE 102018124232 [0002]

Claims (10)

Method for detecting an angular position (ω) of a rotating component by a sensor unit (10), comprising a sensor element (20) with a transmitting element that emits a sensor signal (22) and a receiving element that receives the sensor signal (22) with the rotating component connected and rotatable about an axis of rotation first reflection element (12), which reflects the sensor signal (22), and the receiving element receives the reflected sensor signal (22), the transit time of the sensor signal (22) being detected as a measurement signal (Y, 112) and the first reflection element (12) causes a measurement distance which is variable as a function of the rotation about the axis of rotation and which is run through by the sensor signal (22) and thus causes a periodic change in the measurement signal (Y, 112), characterized in that the rotating component comprises a total of n Reflection elements (12, 14, 16, 18, 26) which are rotatable and are each arranged fixedly rotated relative to one another are connected, each of which reflect the sensor signal (22) and the receiving element receives these respectively reflected sensor signals (22), the respective transit time of the sensor signal (22) being the first to assigned to the respective first to nth reflection element (12, 14, 16, 18, 26) nth measurement signal (Y _i , 112, 114, 116, 118, 126) is detected and the n measurement signals (Y _i , 112, 114, 116, 118, 126) are mutually displaced by the offset angle (α), the Number n ≥ 3 and an angular position (ω) of the rotary component depending on a measurement signal (Y _i , 112, 114, 116, 118, 126) of one of the reflection elements i ∈ n (12, 14, 16, 18, 26), one Measurement signal (Y _i-1 ) of the reflection element i-1 adjacent on the one hand and a measurement signal (Y _{i + 1} ) of the reflection element i + 1 adjacent on the other is determined. Procedure according to Claim 1 , characterized in that the respective reflection element (12, 14, 16, 18, 26) is non-rotatably connected to the rotating component or is made in one piece with the rotating component. Procedure according to Claim 1 or 2nd , characterized in that the reflection elements (12, 14, 16, 18, 26) are arranged rotated by the offset angle (α). Method according to one of the preceding claims, characterized in that the measurement signal (Yi) of the i-th reflection element by a linear approximation (32) between an intersection (40) of the i-th measurement signal (Yi) with a further measurement signal and a further intersection point (40) of the i-th measurement signal (Yi) is written with another further measurement signal. Procedure according to Claim 4 , characterized in that the linear approximation (32) takes place in a measuring range (36) which delimits the maximum and minimum of the i-th measuring signal (Yi). Procedure according to Claim 4 or 5 , characterized in that the linear approximation (32) is divided into several angular ranges (30) with a straight line (34) assigned to each angular range (30) and the number of angular ranges (30) over a full period of the i-th measurement signal (Yi ) is 2 · n. Procedure according to Claim 6 , characterized in that an allocation table (48) can be used to determine the angular range (30) in which the measurement signal (Yi) to be used for determining the angular position (ω) via the linear approximation (32) lies. Method according to one of the preceding claims, characterized in that, in addition to the i-th measurement signal (Yi), a measurement signal i + 1 (Y _{i + 1} ) following this and a measurement signal i-1 (Y _i-1 ) preceding this is recorded and depending on this, the angular position (ω) is determined. Method according to one of the preceding claims, characterized in that the angular position (ω) is determined as a function of a difference between the measurement signals i + 1 (Y _{i- +} ) and i-1 (Y _{i + 1} ). Sensor unit (10) for detecting an angular position (ω) of a rotating component, comprising a sensor element (20) with a transmitting element which emits a sensor signal (22) and a receiving element which receives the sensor signal (22), and which is connected to the rotating component first reflection element (12) rotatable about an axis of rotation, which reflects the sensor signal (22), and the receiving element receives the reflected sensor signal (22), the transit time of the sensor signal (22) being detected as a measurement signal (Y, 112) and the first reflection element (12) a measuring distance which is variable as a function of the rotation about the axis of rotation and which is run through by the sensor signal (22), and thus a periodic change in the measuring signal (Y, 112), characterized in that the detection of the angular position of the reflection element (12, 14, 16 , 18, 26) by a method according to one of the preceding claims.

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