EP3180591A1 - Method for determining an orthogonality error between two sensor signals - Google Patents

Method for determining an orthogonality error between two sensor signals

Info

Publication number
EP3180591A1
EP3180591A1 EP15749828.8A EP15749828A EP3180591A1 EP 3180591 A1 EP3180591 A1 EP 3180591A1 EP 15749828 A EP15749828 A EP 15749828A EP 3180591 A1 EP3180591 A1 EP 3180591A1
Authority
EP
European Patent Office
Prior art keywords
error
sensor signals
determining
sensor
angle
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP15749828.8A
Other languages
German (de)
French (fr)
Inventor
Jens GLEISSBERG
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Continental Automotive GmbH
Original Assignee
Continental Automotive GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to DE102014216224 priority Critical
Application filed by Continental Automotive GmbH filed Critical Continental Automotive GmbH
Priority to PCT/EP2015/068710 priority patent/WO2016024000A1/en
Publication of EP3180591A1 publication Critical patent/EP3180591A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01DMEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D5/00Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
    • G01D5/12Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
    • G01D5/244Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
    • G01D5/24471Error correction
    • G01D5/24476Signal processing

Abstract

Method for determining an error (y) between two sensor signals (s1, s2) in an angle sensor which, on the basis of an angle transmitter, outputs the sensor signals (s1, s2) which have a periodic profile and are mathematically in an orthogonal relationship with one another, wherein a deviation from the orthogonal relationship between the sensor signals can occur on account of the error (y), having the steps of: - forming a radius signal (e_orth) using the sums of squares of the sensor signals, - determining the 2*nth harmonic of the radius signal (e_orth), where n is equal to a positive integer, and - determining the error of a value of the amplitude at the second harmonic, which value has been phase-shifted through 90° with respect to the rotation angle value.

Description

Method for determining an orthogonality error between two sensor signals

The invention relates to a method for determining an error between two sensor signals in an angle sensor.

From the prior art, the document DE 10 2010 003 201 AI is known, in which a method for determining a rotation angle with an angle measuring unit is disclosed. In this ¬ writing is disclosed, as the rotational angle with a corrective ¬ turwert can be determined so that the influence of an error or an error angle F to the value of the rotation angle is eliminated as possible. This is an error, resulting from a not quite exact orthogonality between a sine and cosine-shaped sensor signal of the sensor element resul ¬ advantage.

The object of the invention is to provide a method with which the value of the error can be determined as simply as possible.

The object is achieved according to a method according to claim 1. Further advantageous embodiments of the method according to the invention are the subject of the dependent claims, which are explicitly made by Be ¬ access to the subject of the description.

The sensor signals are a periodic signal, for example, a sine and a cosine signal, which are shifted by 90 ° to each other phases. Due to the orthogonal relationship between the sensor signals, the sensor signals should satisfy the condition according to the addition theorem sin 2 (x) + cos 2 (x) = 1, with x as the value of the rotation angle. From the sensor signals, therefore, the radius signal, preferably to sin 2 (x) + cos 2 (x), formed so that this size is used as an indicator of the quality of the sensor signals.

The invention is based on the basic idea that the error has an immediate effect on the amplitude of the second or an integral multiple of the second harmonic of the radius signal and therefore an analysis of the amplitude of the second harmonic gives a direct indication of the magnitude of the error. In particular, the invention is based on the recognition that the error occurs in the second harmonic of the radius signal with a phase shift of 90 ° to the rotation angle, so that the imaginary portion of the harmonic results in an exclusion of the error. The advantage of the invention lies in the fact that the error can be determined on the basis of the radius signal, which can be determined solely on the basis of the two sensor signals. Since these signals are necessary anyway for determining the angle of rotation, there is no need to change existing rotational angle sensors. There is no need reference sensor signal with which the sensor signals could be compared individually to determine the error in the individual sensor signals. The method can therefore be integrated particularly easily into existing systems, since the electronic means necessary for the evaluation of the sensor signals are present anyway.

The mathematical derivation follows as follows. The amplitude of the radius signal can be mapped by the equation e_orth (x) = sin 2 (x) + cos 2 (x + y), where x is the value of the angle of rotation and y is the value of the error. If the error is y = 0, the aforementioned condition of the addition theorem is satisfied. Among other things, the amplitude of the radius signal has a maximum at an angle of 45 °, so that the radius signal assumes the following value at x = 45 °: e_orth (45 °) = 1-sin (y)

By way of example, the value of 45 ° is used here. The second harmonic can also be examined at other locations where it reaches a minimum or a maximum.

The error has an effect on the imaginary part of the second harmonic, so that the value of the error is based on the equation y = aresin I e_orth, 2 * n. , I can detect. It is particularly advantageous to carry out the analysis of the harmonic wave by means of a Fourier transformation, since in this way the values of the second harmonic at the maximas or minimas are directly obtained, and in this way the analysis of the second harmonic can be carried out easily. Depending on the application, it is possible to determine the error before commissioning an angle sensor or during operation of the angle sensor. Depending it is useful depending ¬ stays awhile form of the Fourier transform (FT) input. Advantageous features include the discrete FT, fast FT or a combination of both FT.

The determination of the error can be performed directly by means of an evaluation unit of the rotation angle sensor or a separate computing unit on the sensor element. The invention includes Therefore, an angle sensor with a sensor element for detecting two sensor signals and a computing unit for determining the error according to the inventive method. The object is further achieved according to an alternative method according to the independent claim 8.

It is conceivable to carry out the Fourier transformation also on the basis of the rotation angle calculated from the sensor signals. Due to the existing orthogonality error, the rotation angle determined from the sensor signals causes an error in the result of the Fourier transformation, so that a conclusion on the orthogonality error is possible from this result. The invention will be explained in more detail with reference to figures. Show it:

Fig. 1 is a representation of the sensor signals and the radius ¬ signal and the error in the sensor signals. Figure 1 shows two diagrams, wherein in a first diagram A, the sensor signals sl (sine) and s2 (cosine) are shown for a period. In a second diagram B, the radio ¬ ussignals e_orth is shown that is derived from the sensor signals sl, s2. Above the diagram A, enlarged sections from the diagram A are shown. These sections show the sensor signals sl, s2 in the region of the zero crossing. It can be seen that due to the orthogonality error or the error y, the actual zero crossing does not occur at the intended rotation angle x_null but before or after it (abscissa represents the rotation angle). At the actual zero rotation angle x_null, the sensor signal ¬ a deviation from the zero value, which represents an offset Off c

 5

In the diagram A, a period of the sensor signals sl and s2 can be seen in each case. The radius signal, which can be determined from this, has two periods and forms the second harmonic of the sensor signals s1, s2. The result of the orthogonality of the two sensor signals is that exactly the second harmonic reaches a maximum at the crossing points of the two sensor signals s1, s2 (see diagram B), so that the error Y is quantified directly in absolute terms on the basis of the imaginary portion of the radius signal at the maxima ¬ zierbar is. The real portion of the radius signal, however, represents a scaling error or. is a gain error, ie is a characteristic for the different amplifications of the amplitudes of the sensor signals sl and s2.

The orthogonality error between the two sensor signals usually does not change over the life of the win ¬ kelsensors. Therefore, it may be sufficient to errors before commissioning ¬ sioning, it is to determine in a vehicle or before completion of the production and balance. For this purpose, an external arithmetic unit can be used to read out the sensor signals sl, s2 and to determine the error. Depending on the existing computing power of the evaluation, with which the angle sensor is operated, but it may also be advantageous to the determination and compensation of the error online, ie to perform during operation.

In order to determine this error, the radius signal e_orth is formed from the known sensor signals s1 and s2, and a harmonic analysis is carried out for this signal e_orth. For this purpose, the radius signal is preferably converted into a frequency space by means of an FT analysis and the imaginary portion of the second harmonic is determined therefrom. Subsequently, the Aresin is calculated for this value, from which one receives the error or the angular offset. For a period, the following calculation e_orth, 2 = 0.02 + 0.0175i, results for the illustrated radius signal by way of example

For the orthogonality error, the crucial part is the imaginary part, which in this case assumes the value 0.0175. The orthogonality error therefore results from the equation: y = aresin (0, 0175) = 1 °

Depending on the number of periods considered, it may also be a 2 * nth harmonic which has to be analyzed. In ¬ play as you would use in a calculation of the error over five periods the 10th harmonic for determining the error.

Claims

claims
1. A method for determining an error (y) between two sensor signals (sl, s2) in an angle sensor which outputs the sensor signals (sl, s2) in dependence on an angle sensor, which have a periodic course and are mathematically in an orthogonal relationship to one another, wherein, due to the error (y), a deviation from the orthogonal relationship between the sensor signals may occur, comprising the steps of:
 Forming a radius signal (e_orth) by means of the sums of squares of the sensor signals,
 - Determining the 2 * nth harmonic of the radius signal (e_orth), with n equal to a whole positive number, and - Determining the error of a phase-shifted by 90 ° to the rotational angle value of the amplitude at the second harmonic.
2. The method according to claim 1, characterized by
 - Determining a frequency component or shares of
Radius signal by means of a Fourier transform, and
- Determine the error based on the imaginary part of the frequency component or the frequency components of the second harmonic.
3. The method according to claim 2, characterized in that the Fourier transformation is performed by means of a fast and / or discrete Fourier transformation. 4. The method according to claim 2 or 3, characterized by,
Compute the error y using the equation y = aresin I e_orth, 2 * n. , im i is determined, where e_orth, 2nd, in the imaginary part of the amplitude of the 2 * n-th harmonic of the radius signal maps.
Method according to one of the preceding claims, characterized in that the real part of the 2 * n-th harmonic as a measure of a scaling error ¬ turns is ver.
Method according to one of the preceding claims, characterized in that the method is used during operation.
Method according to one of claims 1-5, characterized ge ¬ indicates that the method is carried out before commissioning of an angle sensor, in particular by means of an external processing unit.
Method for determining an error (y) between two sensor signals (sl, s2) in an angle sensor which outputs the sensor signals (sl, s2), which have a periodic course and are mathematically in an orthogonal relationship as a function of an angle sensor, due to the error (y) may cause a deviation from the orthogonal relationship between the sensor signals, comprising the steps of:
 Determining a rotation angle (x) from the sensor signals (sl, s2),
 Determining a conversion value by performing a Fourier transformation for the determined rotation angle,
- Determine the error based on the conversion value.
9. An angle sensor for detecting a rotation angle, comprising
- a sensor element that outputs the sensor signals in dependence on an angle encoder ¬ having a periodi ¬'s course and to each other mathematically in an orthogonal relationship, and
 - A computing unit for carrying out the method according to any one of the preceding claims.
EP15749828.8A 2014-08-14 2015-08-13 Method for determining an orthogonality error between two sensor signals Withdrawn EP3180591A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
DE102014216224 2014-08-14
PCT/EP2015/068710 WO2016024000A1 (en) 2014-08-14 2015-08-13 Method for determining an orthogonality error between two sensor signals

Publications (1)

Publication Number Publication Date
EP3180591A1 true EP3180591A1 (en) 2017-06-21

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP15749828.8A Withdrawn EP3180591A1 (en) 2014-08-14 2015-08-13 Method for determining an orthogonality error between two sensor signals

Country Status (6)

Country Link
US (1) US20170146370A1 (en)
EP (1) EP3180591A1 (en)
KR (1) KR20170029607A (en)
CN (1) CN106574857A (en)
DE (1) DE102015215511A1 (en)
WO (1) WO2016024000A1 (en)

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5463393A (en) * 1991-12-05 1995-10-31 Acutronic Ag Method and apparatus for correcting errors in an amplitude encoded signal
DE10163504B4 (en) * 2001-12-21 2005-07-07 Siemens Ag Method for iterative error compensation of sin / cos position measuring systems for offset, amplitude and phase errors
WO2005050140A1 (en) * 2003-11-18 2005-06-02 Koninklijke Philips Electronics N.V. Position determining
DE102004038621B3 (en) * 2004-08-09 2006-02-16 Siemens Ag Determination procedure for a position signal
JP4713123B2 (en) * 2004-10-13 2011-06-29 株式会社ミツトヨ Encoder output signal correction device
JP4568298B2 (en) * 2007-03-16 2010-10-27 オークマ株式会社 Position detection device
JP5120384B2 (en) * 2008-02-07 2013-01-16 日立金属株式会社 Rotation angle detection device, rotator, and rotation angle detection method
JP2010156554A (en) * 2008-12-26 2010-07-15 Okuma Corp Position detecting apparatus
DE102010003201A1 (en) 2009-05-08 2010-12-23 Continental Teves Ag & Co. Ohg Angle-measuring method for determining an angle of tilt/swiveling angle uses an angle-measuring unit and first and second measuring signals
DE102011081743B4 (en) * 2010-08-30 2019-05-09 Rigaku Corp. Motion control system and X-ray measuring device
JP5798824B2 (en) * 2011-07-22 2015-10-21 株式会社ミツトヨ Scale error calculation device, scale error calibration device, and scale error calculation method
JP5836026B2 (en) * 2011-09-08 2015-12-24 三菱重工業株式会社 Error frequency component acquisition device, rotation angle acquisition device, and motor control device

Also Published As

Publication number Publication date
US20170146370A1 (en) 2017-05-25
KR20170029607A (en) 2017-03-15
DE102015215511A1 (en) 2016-02-18
WO2016024000A1 (en) 2016-02-18
CN106574857A (en) 2017-04-19

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