DE102017202217A1 - Method and device for correcting an output signal of a measuring device - Google Patents

Abstract

The invention relates to a method for correcting at least one output signal (A, B) of a measuring device (2), wherein the measuring device (2) generates a first wave-shaped output signal (A) and at least one further wave-shaped output signal (B), wherein a phase correction value in dependence a signal waveform of the first and the further output signal (A, B) over at least one period of one of the output signals (A, B) is determined or calculated, wherein a phase position of at least one of the output signals is corrected in dependence on the phase correction value.

Description

The invention relates to a method and a device for correcting at least one output signal of a measuring device, in particular a displacement measuring device.

Displacement measuring devices, in particular so-called incremental measuring systems, e.g. Linear or rotary measuring systems are used in many measuring and processing machines. Regardless of the measuring principle, incremental measuring systems can be a material measure, e.g. a scale, in particular a graduated scale, comprise, on the detectable with a constant stroke period marks, in particular lines are applied. Furthermore, such an incremental measuring system comprises a reading head for detecting the marks. In simple terms, the measurement principle is to count detected strokes when moving the measuring device along the line scale with the help of the reading head. By means of the known bar period and the number of bars counted, an incremental position information can thus be determined. Typically, stroke marks can be optically detected.

Although the pure counting of the bars makes it possible to determine the position, it must be ensured that the direction of movement of the reading head does not change during counting. By pure counting, no direction of movement is determinable. In order to also enable a direction determination, incremental measuring systems, in particular their read heads, typically comprise two detectors for detecting the marks, wherein the read heads are offset relative to each other by a quarter stoke period. Theoretically, these detection devices generate two signals phase-shifted by 90 ° relative to one another when the read head is moved along the line scale.

It is further known that the output signals generated by the detection devices of the read head are rectangular or are converted into rectangular signals, for example by known threshold-based methods. However, with such rectangular output signals, the path resolution is only one quarter of the stroke period.

In order to enable an improved path resolution, substantially wave-shaped output signals can also be generated, for example based on an intensity of a detected radiation. Ideally, e.g. the output signals of the measuring device be sinusoidal and cosinusoidal.

und ein weiteres Ausgangssignal $$\text{B=cos}\left(\text{s/l}\times \text{2}\times \mathrm{\pi }\right)$$

In this case, for example, a first output signal can be described by the following formula $$\text{A = sin}\left(\text{s / l}\times \text{2}\times \mathrm{\pi }\right)$$

and another output signal $$\text{B = cos}\left(\text{s / l}\times \text{2}\times \mathrm{\pi }\right)$$

Here s denotes a distance covered and I the period length. The period length may correspond to the (angular) distance along the distance from the beginning of a mark to the beginning of the next mark.

If, under ideal conditions, ie without the offset, amplitude and phase errors explained in more detail below, signal values A and B are plotted against one another, for example by plotting values of the first output signal A as abscissa values and the corresponding values of the further output signals B as ordinate values of points are, the applied points lie on a circle, which is concentric to the origin. A complete loop around the circle is generated when the read head that generates the signals A, B travels the distance of one period length. A direction of movement of the reading head determines the direction of rotation, that is, a clockwise or counterclockwise direction. An exact evaluation of the position within a period length can now be done by determining a phase phi with respect to the signal axes. The phase angle is calculated in particular as $$\text{phi = atan2}\left(\text{A}\text{, B}\right)$$

Thus, an interpolated position within a stroke period of the stroke scale is calculated as $$\text{s}=\left(\text{atan2}\left(\text{A}\text{, B}\right)\times \text{l}\right)/\left(2\times \mathrm{\pi }\right)$$

Here, atan2 denotes a function equivalent to the known atan function, but with a periodicity of 2 × π.

An accuracy with which the interpolated position can now be determined within a period of the scale, then also depends on the digital resolution, which is determined for example by an A / D converter. With line scales of a period length of I = 40 μm, for example, resolutions in the sub-micron range can be achieved.

However, the position determination described so far only leads to a correct result if the output signals generated have the same amplitude and no offset value different from zero and are exactly 90 ° out of phase with each other.

Due to tolerances and the mechanical arrangement of the detection devices in the read head, however, none of the mentioned requirements for the output signals is generally met.

Thus, output signals with mutually different amplitudes can be generated. These can lead to a two-wave position deviation from an ideal value within one period.

If one or both output signals are not offset-free, this can lead to a single-shaft position deviation within one period.

90 ° different phase shifts between the output signals can cause two-wave positional deviations from an ideal position within one stroke period.

In order to minimize the errors in the position determination caused by a phase shift which differs from 90 °, it is known to mechanically align the detection devices in the read head precisely. However, this alignment is time-consuming.

Next is known to the solution to use measuring systems with a shorter period length, which are priced but significantly more expensive.

Also known are methods for suppressing systematic errors of incremental position encoders. That's how it describes DE 100 36 090 A1 a method for suppressing systematic errors of incremental position or rotary encoders with at least two shifted by a phase angle, approximately sinusoidal track signals. Here, the length of the complex pointer with the sine or cosine of the double angle described by the track signals is weighted by the current position within one period of the track signals. With the variables thus determined, a correction of the amplitude error and angle error is performed by means of an arithmetic unit.

The DE 10 2004 038 621 B3 discloses a detection method for a position signal, wherein signals corrected from the measurement signals using correction values are determined, wherein the correction values may include two offset correction values, at least one amplitude correction value, at least one phase correction value for the measurement signals.

The DE 101 63 504 A1 discloses a closed loop method which, after a few iterations of a Fourier analysis, provides an approximately accurate result for desired correction values that can be used for iterative error compensation of sine / cosine attitude measurement systems for offset, amplitude, and phase errors.

The DE 199 14 447 A1 discloses a self-calibrating position transducer system wherein transducer signals are corrected using calibration values.

This raises the technical problem of providing a method and a device for correcting at least one output signal of a measuring device, which enable a temporally fast and with little computational effort and thereby accurate correction.

The solution of the technical problem results from the objects with the features of claims 1 and 15. Further advantageous embodiments of the invention will become apparent from the dependent claims.

Proposed is a method for correcting at least one output signal of a measuring device. The measuring device may in particular be a displacement measuring device, more particularly an incremental displacement measuring device. Alternatively, the measuring device may be an incremental angle measuring device.

As described in the introduction, the measuring device may comprise a measuring device, in particular a line measure, in particular in the form of a measuring tape, wherein the measuring device has detectable marks. Immediately adjacent marks may, as previously explained, be arranged at a predetermined period length on or in the measuring device.

The measuring device may in this case comprise a movable reading head. The measuring device, in particular the reading head, may further comprise at least one, but preferably exactly or at least two, detection devices for detecting or detecting the marks which generate output signals along the measuring device when the detection device (s) are moved. Various measuring principles are applicable here. In particular, however, the measuring device may be an optical measuring device, wherein the detection devices are optical detection means for generating the output signals.

The measuring device is thus designed such that, in particular when the at least one detection device is moved along the measuring device, it generates a first wave-shaped output signal and at least one further wave-shaped output signal. The output signals generated in the process can be phase-shifted relative to each other with a non-zero phase shift. In particular, the first wave-shaped output signal can be so out of phase with the further output signal that the first output signal leads the further output signal in a first movement direction of the detection device (s) and lags the further output signal in a direction of movement opposite to the first movement direction.

Ideally, the phase shift between the output signals is 90 °. Due to the errors explained in the introduction, however, the phase shift can deviate from 90 °.

A wave-shaped signal may in particular designate a substantially sinusoidal signal. Of course, however, it is possible that a wave-shaped signal in addition to a fundamental vibration also comprises or has so-called harmonic components.

A wave-shaped output signal may in this case have an amplitude, wherein the amplitude denotes a maximum value of the offset-free output signal or half of the difference between the maximum value and the minimum value of the output signal.

Further, the output signal may have a nonzero offset.

According to the invention, a phase correction value, in particular an amount of the phase correction value and / or a sign of the phase correction value, is calculated. The calculation of the phase correction value, in particular of the magnitude and / or the sign, can be an analytical calculation here. In other words, the phase correction value can be determined as the output value (function value or output variable) of an analytical function, wherein function arguments (input variables) of the function are the output signals, in particular their signal values, are determined as a function of or from the signal values of the output signals or properties of the output signals depend. In other words, the phase correction value can be calculated as a closed-form solution.

It is possible that the amount of the phase correction value is calculated and the sign of the phase correction value is determined.

Furthermore, the phase correction value is determined as a function of an amplitude characteristic of the first and further output signals over at least one period of one of the output signals. In particular, the phase correction value can be determined as a function of an amplitude characteristic of amplitude-corrected and offset-corrected output signals.

By an amplitude correction, the amplitude of the corresponding output signal to a predetermined value, in particular a dependent of an A / D converter value, for example, to the value 1, normalized. By means of an offset correction, an offset of the output signal can be corrected to the value 0.

In particular, the phase correction value can be determined as the difference between 90 ° and a current phase shift between the phase-corrected output signals.

In the method, a course of the first and the further output signal over at least one period of the first output signal and / or the further output signal is detected. In this case, a period of an output signal is generated when the at least one detection device is moved by a period length along the measuring device with a constant direction of movement.

Preferably, a profile of the output signals over a plurality of periods of the first output signal and / or the further output signal is detected. For this purpose, the at least one detection device of the measuring device, in particular the reading head, can be moved along the measuring device.

Furthermore, a phase position of at least one of the output signals is corrected as a function of the phase correction value, in particular changed. The correction of the phase position can be effected by a correction or change of the amplitude values of the amplitude characteristic of at least one of the output signals. In particular, the phase correction value is determined such that after correction of the phase position of at least one of the output signals, the phase shift between the output signals is 90 °.

In other words, a phase correction of the first and / or the further output signal is carried out in dependence on the first output signal and the further output signal, in particular as a function of their signal characteristics. Here, a phase correction may designate the calculation of a phase-corrected first output signal. Alternatively or cumulatively, the phase correction may also designate the calculation of a phase-corrected further output signal.

In particular, the phase correction is performed such that the first and the further output signal after the phase correction are 90 ° out of phase with each other.

The phase correction can be carried out on the basis of analog output signals or based on digitized output signals.

It is possible in this case for the phase correction value to be determined in a calibration pass of the measuring device. In the calibration pass, as previously explained, the at least one detecting means may be slid along the measuring means to produce output signals, the phase correction value being determined in response to the output signals generated. During runtime of the measuring device, in particular in a measuring operation, this explained phase correction can then be carried out as a function of this, in particular stored, phase correction value.

However, it is also possible to determine the phase correction value at runtime, in particular during measurement operation. Even at runtime, output signals are generated and can thus be used to calculate the phase correction value. Depending on the thus determined phase correction value then at least one of the output signals can be corrected. Then, a position determination in dependence of the (phase) corrected output signals can be performed.

The method for determining the position as a function of the output signals is known to the person skilled in the art. One possible method has already been explained in the introduction.

This advantageously results in a phase correction of the output signals of a measuring device that is fast in time and can be realized with little computational effort or circuit complexity. Furthermore, the position can be determined as a function of the phase-corrected output signals. As a result, a more accurate position determination is made possible in an advantageous manner.

In a further embodiment, an amount of the phase correction value is determined in dependence on a curve of a sum of the squared signal value of the first output signal and the squared signal value of the further output signal over the at least one period. In other words, as Summation over at least one period determines the sum of the squared signal values of the output signals.

This results in an advantageous manner computationally simple and thus temporally quickly feasible calculation of the phase correction value.

In a further embodiment, the amount of the phase correction value is determined as a function of a maximum value of the course of the sum and a minimum value of the course of the sum. In other words, a maximum value and a minimum value of the sum is determined over the at least one period, wherein the amount of the phase correction value is then determined as a function of the maximum and minimum values.

If, as explained above, the output signals are plotted relative to one another such that signal values of the first output signal form abscissa values and the corresponding signal values of the further output signal ordinate values of points, these points ideally lie on a circle, wherein a value of the sum of the squared signal values is a distance of one Point represented by an origin of this circle. If signal values of offset- and amplitude-corrected output signals are plotted, this distance may correspond to a predetermined value, for example one, even if the phase shift between the output signals is exactly 90 °.

Corresponding signal values denote signal values that are generated at a position of the measuring device.

If, as described, the signal values are plotted as described during movement of the measuring device along the measuring device by at least one period length, then the points lie on a circle with the radius 1 in the case of amplitude, offset and phase-corrected output signals.

However, if the phase shift deviates from 90 °, then the points plotted as explained lie on an ellipse. With increasing amount of the deviation of the phase shift of 90 °, this ellipse becomes slimmer, ie the quotient between the length of a first major axis of the ellipse and a second major axis of the ellipse larger. Depending on the sign of the deviation of the phase shift of 90 °, the first main axis extends in the first and third quadrants of the coordinate system comprising the abscissa and ordinate or in the second and fourth quadrant. In particular, in the case of positive phase correction values, the first main axis of the ellipse may be arranged in the second and fourth quadrants and in the case of negative phase correction values in the first and third quadrants.

In this case, the explained maximum value of the summation profile can represent half the length of the first main axis of the explained ellipse. In this case, the minimum value of the summation profile can represent half the length of the second main axis of the explained ellipse.

berechnet werden, wobei „A“ einen Signalwert des ersten Ausgangssignals und „B“ einen Signalwert des weiteren Ausgangssignals repräsentiert. Formel 5 ermöglicht somit in vorteilhafter Weise die analytische Bestimmung eines Betrags des Phasenkorrekturwerts.In particular, the phase correction value according to $$\text{p =}\left(\text{atan}\left(\text{sqrt}\left(\text{rmaxmin}\right)\right)-\mathrm{\pi }\text{/}4\right)\times 2=(\text{atan}\left(\text{sqrt}\left(\text{Max}\left({\text{A}}^2+{\text{B}}^2\right)\right)/\left(\text{min}\left({\text{A}}^2+{\text{B}}^2\right)\right)-\mathrm{\pi }/4\right)\times 2$$

where "A" represents a signal value of the first output signal and "B" represents a signal value of the further output signal. Formula 5 thus advantageously enables the analytical determination of an amount of the phase correction value.

This analytical form advantageously enables a timely but accurate determination of the phase correction value.

In a further embodiment, a sign of the phase correction value is determined as a function of a curve of a sum of the signal value of the first output signal and the signal value of the further output signal over at least one period. In other words, the sum of the signal values of the output signals is determined as summation profile over at least one period. This advantageously results in a simple determination of the sign that is fast in time but robust.

In a further embodiment, the sign is determined as a function of a maximum value of the course of the sum. If the output signals are offset and amplitude corrected outputs, the sign of the phase correction value may be positive if the maximum value of this waveform is less than or equal to sqrt (2). Further, the sign of the phase correction value may be negative if the maximum value of this curve is greater than sqrt (2).

Overall, a reliable and robust determination of the magnitude and the sign of the phase correction value and thus a temporally fast and accurate correction of the output signals. This in turn allows a more accurate position determination.

In an alternative embodiment, the phase correction value is determined in dependence on at least one parameter of a parameterized ellipse equation, wherein the at least one parameter is determined such that a deviation of points of a set of points from the ellipse described by the ellipse equation is minimized, if any Abscissa value of a point in dependence on the first output signal, in particular a signal value of the first output signal, and an ordinate value of the point in dependence of the corresponding further output signal, in particular a signal value of the corresponding further output signal is determined.

Preferably, the at least one parameter may be determined such that a deviation of points of a rotationally transformed set of points from the ellipse described by the ellipse equation is minimized if the first output signal, in particular a signal value of the first output signal, an abscissa value and the corresponding one Output signal, in particular a signal value of the further output signal, an ordinate value of a point of the not yet rotationally transformed point set, the rotation transformation causes a rotation of the points of the not yet rotationally transformed point set by 45 ° about an axis perpendicular to the ordinate and abscissa axis of rotation.

Thus, the coordinates of the points of the not yet rotationally transformed point values are determined as a function of the output signals, in particular the signal values of the output signals, over at least one period. Thereafter, the set of points is rotationally transformed, whereby the coordinates of the points of the not yet rotationally transformed point values are transformed. Further, the parameters of an ellipse are determined such that a deviation between the ellipse and the points of the rotationally transformed point set is minimized.

In particular, the phase correction value is determined as a function of two parameters of the parameterized elliptic equation, in particular as a function of a quotient of the two parameters. Preferably, a parameter determined in this way represents half the length of one of the two main axes.

If a phase shift between the first and the further output signal deviates from 90 °, then the points for which the first output signal is an abscissa value and the further output signal form an ordinate value lie on an ellipse whose principal axes are at 45 ° with respect to the abscissa or ordinate are twisted. Since a parameterized ellipse equation usually describes an ellipse whose principal axes are oriented parallel to the ordinate or the abscissa, it is necessary for an accurate calculation of the length of the main axis to change the set of points by the rotation transformation such that the main axes of the Point set approximate ellipse are also oriented parallel to the ordinate or abscissa.

The rotation transformation can be carried out in particular by multiplying the point coordinates of the points of the not yet rotationally transformed point set with a rotation matrix. In this case, the multiplication of the point coordinates of the points of the rotationally transformed point set is calculated.

A signal value of the first output signal and, as the ordinate value of the point, a corresponding signal value of the further output signal are determined in each case as the abscissa value of a point of the point set for the points of the point set that has not yet undergone rotational transformation. Coordinates of different points of the set of points can hereby be determined as a function of corresponding signal values of the output signals which are generated during the movement of the measuring device by at least one period length. Corresponding signal values denote signal values that are generated at a position of the measuring device.

Then parameters of an ellipse can be determined such that the ellipse minimizes a distance of the points of the rotationally transformed set of points from the ellipse (best fit). In particular, the at least one parameter (and thus also the phase correction value) can be determined numerically, in particular by an iterative method. Also, the at least one parameter (and thus also the phase correction value) can be determined by an optimization method, in particular an iterative optimization method.

beschrieben werden. Hierbei können diese Parameter A0, B0, a², b² numerisch und/oder durch ein Optimierungsverfahren, welches dem Fachmann bekannt ist, bestimmt werden. Der Phasenkorrekturwert kann dann in Abhängigkeit der Parameter a² und b² bestimmt werden. Insbesondere kann der Phasenkorrekturwert gemäß $$\text{p}=\left(\text{atan}\left(\text{sqrt}\left(\text{a/b}\right)\right)-\mathrm{\pi }/4\right)\times 2$$

bestimmt werden.If, as previously explained, the first output signal or a signal value of the first output signal is denoted by "A" and the corresponding further output signal or a signal value of the corresponding further output signal is denoted by "B", then "A" forms an abscissa value and "B" an ordinate value of a point of the not yet rotationally transformed point set. If R (A) is an abscissa value and R (B) is an ordinate value of the rotationally transformed point of the rotationally transformed point set, then an ellipse can be given by the equation $${\left(\text{R}\left(\text{A}\right)-\text{A}0\right)}^2/{\text{a}}^2+{\left(\text{R}\left(\text{B}\right)-\text{B}0\right)}^2/{\text{b}}^2-1=0$$

to be discribed. In this case, these parameters A0, B0, a ² , b ^{2 can be determined} numerically and / or by an optimization method which is known to the person skilled in the art. The phase correction value can then be determined as a function of the parameters a ² and b ² . In particular, the phase correction value according to $$\text{p}=\left(\text{atan}\left(\text{sqrt}\left(\text{from}\right)\right)-\mathrm{\pi }/4\right)\times 2$$

be determined.

This results in an advantageous manner a simple and temporally quickly feasible method for determining the phase correction value, in particular both the amount and the sign.

In another embodiment, a phase-corrected first output signal is determined by forming a difference between the phase-corrected first output signal and a phase-corrected further output signal multiplied by the sine value of the phase correction value and dividing by a cosine value of the phase correction value. Specifically, a value of the phase-corrected first output signal is determined by forming a difference between the value of the phase-corrected first output signal and a value of the phase-corrected further output signal multiplied by the sine value of the phase correction value and dividing by a cosine value of the phase correction value.

wobei p den erläuterten Phasenkorrekturwert und α die idealerweise korrekte Phasenlage des Sinussignals bezeichnet.Here it can be assumed that the following applies to a phase-shifted sinusoidal curve: $$\text{sin}\left(\mathrm{\alpha }+\text{p}\right)=\text{sin}\left(\mathrm{\alpha }\right)\times \text{cos}\left(\text{p}\right)+\text{cos}\left(\mathrm{\alpha }\right)\times \text{sin}\left(\text{p}\right)$$

where p denotes the explained phase correction value and α denotes the ideally correct phase position of the sine signal.

bestimmt werden, wobei davon ausgegangen wird, dass das weitere Ausgangssignal eine bereits korrekte Phasenlage aufweist.Thus, the corrected sine signal as $$\text{sin}\left(\mathrm{\alpha }\right)=\left(\text{sin}\left(\mathrm{\alpha \; +}\text{p}\right)-\text{cos}\left(\mathrm{\alpha }\right)\times \text{sin}\left(\text{p}\right)\right)/\text{cos}\left(\text{p}\right)$$

are determined, it being assumed that the further output signal has an already correct phase position.

This advantageously results in a simple and rapid calculation of the corrected first output signal.

In this case, it is not absolutely necessary for a sine and cosine value to be determined, in particular since it can be assumed that the phase correction values are small in magnitude. In this case, a sine value of a phase correction value approximately corresponds to the phase correction value and a cosine value the value one. Thus, an embodiment is described in which a phase-corrected first output signal is determined by forming a difference between the phase-corrected first output signal and a phase-corrected further output signal multiplied by the phase correction value. This advantageously simplifies the calculation of a phase-corrected output signal.

The skilled person is of course clear that assuming a correct phase position of the first output signal in a corresponding manner, a corrected further output signal can be determined. Therefore, assuming a corrected phase position of one of the output signals, it is only necessary to perform the phase correction for the remaining output signal and to determine a correspondingly corrected output signal.

In a further embodiment, an offset correction of the first output signal and / or of the further output signal is additionally performed. Preferably, an offset correction of both output signals is performed. The offset correction has already been explained above. In particular, an offset of an output signal may be determined and then subtracted from the values of the output signal by a subtraction or addition operation. The offset correction can be done by correcting or changing the amplitude curve of both output signals.

Alternatively or cumulatively, preferably cumulatively, an amplitude correction of the first output signal and / or of the further output signal is performed. In particular, an amplitude value of an output signal may be determined, wherein values of the amplitude-corrected output signal are then determined by dividing the values of the amplitude-corrected output signal by the amplitude value, e.g. in a multiplication or division operation. The amplitude correction can be done by correcting or changing the amplitude characteristic of at least one of the output signals.

The above-explained phase correction can be carried out in particular as a function of amplitude- and offset-corrected output signals. In particular, the phase correction value can be carried out as a function of a signal waveform of amplitude-corrected and offset-corrected output signals. This advantageously results in a further improvement in the accuracy in the determination of the phase correction value as well as a further improvement in the accuracy of the position determination as a function of the corrected output signals.

In a further embodiment, in each case at least one signal-specific offset correction value and / or at least one signal-specific amplitude correction value are determined for the first and the further output signal, in particular as a function of the first output signal and / or the further output signal, wherein the first and the further output signal are respectively dependent the signal-specific offset and / or amplitude correction value is corrected.

In particular, as the offset correction value, a value can be determined which is subtracted from the corresponding output signal or added to this output signal. As the amplitude correction value, for example, a value can be determined which normalizes the amplitude of the output signal to the value 1 by a multiplication with the corresponding output signal.

This results in an advantageously computationally simple and fast feasible offset and / or amplitude correction, which in turn allows improved phase correction and thus a more accurate position determination.

In a further embodiment, the at least one offset correction value and / or the at least one amplitude correction value is / are determined numerically. This may mean that the corresponding correction values are not determined analytically, in particular not as a function value of an analytical function.

In particular, it is possible for the offset correction value and / or the amplitude correction value to be determined by an optimization method. This optimization method may in particular be an iterative method.

This results in a determination of an offset and / or amplitude correction value that is sufficiently accurate and can be carried out with reasonable computational effort.

In a further embodiment, the at least one offset correction value and / or the at least one amplitude correction value is determined as a function of at least one parameter of a parameterized elliptic equation, wherein the at least one parameter is determined such that a deviation of points of a set of points from the ellipse caused by the Is minimized if an abscissa value of a point of the set of points in dependence on the first output signal and an ordinate of the point in dependence of the corresponding further output signal is determined, in particular if the first output signal, in particular a signal value of the first output signal, an abscissa value and the further output signal, in particular a signal value of the further output signal, form an ordinate value of the points of the set of points.

In other words, a signal value of the first output signal is determined as the abscissa value of a point of the point set, and a corresponding signal value of the further output signal is determined as the ordinate value of the point. Then parameters of an ellipse can be determined such that the ellipse minimizes a distance of these points from the ellipse (best fit).

Different points of the set of points can be determined in this case as a function of corresponding signal values of the output signals which are generated during the movement of the measuring device by at least one period length.

beschrieben werden, wobei A0 den Offsetwert des ersten Ausgangssignals und B0 den Offsetwert des weiteren Ausgangssignals bezeichnet. Der Faktor 1/a² entspricht einer Amplitude/einem Amplitudenwert des ersten Ausgangssignals. Der Faktor 1/b² entspricht einer Amplitude/einem Amplitudenwert des weiteren Ausgangssignals. Hierbei können diese Parameter A0, B0, a², b² numerisch und/oder durch ein Optimierungsverfahren, welches dem Fachmann bekannt ist, bestimmt werden. Der Offsetwert kann einen Offsetkorrekturwert bilden. Der Amplitudenwert kann einen Amplitudenkorrekturwert bilden. Im Unterschied zur der vorhergehend erläuterten Bestimmung des Phasenkorrekturwerts in Abhängigkeit von Parametern einer Ellipse ist hierbei jedoch keine Rotationstransformation der Punkte vor der Bestimmung der Parameter notwendig.If the first output signal, as previously explained, with "A" and the other output signal with "B", then an ellipse by the equation $${\left(\text{A}-\text{A0}\right)}^2/{\text{a}}^2+{\left(\text{B}-\text{B0}\right)}^2/{\text{b}}^2-1=0$$

A0 denotes the offset value of the first output signal and B0 the offset value of the further output signal. The factor 1 / a ² corresponds to an amplitude / an amplitude value of the first output signal. The factor 1 / b ² corresponds to an amplitude / an amplitude value of the further output signal. In this case, these parameters A0, B0, a ² , b ^{2 can be determined} numerically and / or by an optimization method which is known to the person skilled in the art. The offset value may form an offset correction value. The amplitude value may form an amplitude correction value. In contrast to the previously explained determination of the phase correction value as a function of parameters of an ellipse, however, no rotation transformation of the points is necessary in this case before the determination of the parameters.

A signal correction, in particular an offset and / or amplitude and / or phase correction, can be carried out iteratively.

In a first iteration step, an amplitude and / or offset correction and / or phase correction can be carried out as a function of uncorrected output signals. This can also be referred to as first amplitude and / or offset and / or phase correction.

For example, For example, as previously explained, the offset values and the amplitude values of the output signals can be determined, and an offset and amplitude correction can be carried out in dependence on these values. Then, as likewise explained above, a phase correction (first phase correction) can be carried out in the first iteration step as a function of the offset- and amplitude-corrected output signals.

In a further iteration step, a renewed amplitude and / or offset and / or phase correction can then be carried out as a function of the corrected output signals determined in the preceding iteration step.

For example, as previously explained, the offset values and amplitude values of the corrected output signals determined in the preceding iteration step may be determined again. These newly determined values can then be added to the values determined in the preceding iteration step. Depending on these changed values, a new offset and amplitude correction can then be carried out.

Then, if desired, a renewed phase correction can be carried out in the further iteration step as a function of the offset-corrected and amplitude-corrected output signals.

In an iteration step, an amplitude correction, an offset correction and a phase correction can be performed in a predetermined sequence. For example, an offset and amplitude correction can be performed before the phase correction.

Thus, a desired sequence of correction steps can be performed multiple times.

It is also possible that in a last iteration step not all corrections of the sequence are performed. For example, only one amplitude and / or offset correction, but no phase correction, can be performed in a last iteration step. Alternatively, at least one parameter of a parameterized wave function is determined such that a deviation between an output signal and the parameterized wave function is minimized. Furthermore, the at least one offset correction value and / or the at least one amplitude correction value can be determined as a function of the at least one parameter.

For example, a parameterized wave function can be determined such that exactly or at least one parameter is an offset-specific parameter. Exactly or at least one other parameter of the parameterized wave function can be an amplitude-specific parameter. Of course, exactly or at least one other parameter can be a phase-specific parameter.

The parameters of the parameterized wave function can be determined numerically or by an optimization method.

bestimmt werden, wobei a0 einen offsetspezifischen Parameter und a1, b1 amplitudenspezifische Parameter und ω einen frequenzspezifischen Parameter bezeichnen. Eine Phasenlage des Signals kann in Abhängigkeit bzw. aus einer Kombination der Parameter a1, b1 bestimmt werden, insbesondere als $$\text{ph=atan2}\left(\text{b1/a1}\right)$$

For example, a parameterized wave function can be used as $$\text{f}\left(\text{t}\right)=\text{a0 + a1}\times \text{cos}\left(\mathrm{\omega }\times \text{t}\right)+\text{b1}\times \text{sin}\left(\mathrm{\omega }\times \text{t}\right)$$

where a0 denotes an offset-specific parameter and a1, b1 amplitude-specific parameters and ω a frequency-specific parameter. A phase angle of the signal can be determined as a function of or from a combination of the parameters a1, b1, in particular as $$\text{ph = atan2}\left(\text{b1 / a1}\right)$$

und der Offset als a0 bestimmt werden.The amplitude can be used in particular as $$\text{amp = sqrt}\left(\text{a}{1}^2+{\text{b1}}^2\right)$$

and the offset can be determined as a0.

bestimmt werden kann, wobei A einen Signalwert des ersten Ausgangssignals und B einen Signalwert des weiteren Ausgangssignals über mindestens eine Periode eines der Ausgangssignale bezeichnet."T" denotes a function argument of the parameterized wave function. In particular, "t" may correspond to a phase position of an output signal, where t as $$\text{t = atan2}\left(\text{B}\text{, A}\right)$$

where A denotes a signal value of the first output signal and B denotes a signal value of the further output signal over at least one period of one of the output signals.

Furthermore, in particular by means of nonlinear regression methods known to the person skilled in the art, the parameters for each output signal can be determined separately. In this case, f (t) can correspond to the detected signal value of the respective output signal.

Depending on the parameters determined in this way, in particular the offset, amplitude and phase position explained above, an offset correction value, an amplitude correction value and, if desired, a phase correction value can again be determined. For example, the offset correction value can be determined as a function of the at least one offset-specific parameter. Furthermore, the amplitude correction value can be determined as a function of the at least one amplitude-specific parameter. Furthermore, depending on the at least one phase-specific parameter Phase correction value can be determined. However, the phase correction value can preferably be determined as a function of the phase-specific parameters of the signal waveforms of both output signals.

This may represent an independent invention. Thus, a method for correcting at least one output signal of a measuring device is described, wherein the measuring device generates a first wave-shaped output signal and at least one further wave-shaped output signal, wherein a phase correction value depending on a waveform of the first and the further output signal over at least one period of one of the output signals determined or is calculated, wherein a phase angle of at least one of the output signals is corrected in dependence on the phase correction value. Furthermore, at least one phase-specific parameter of a parameterized wave function is determined in such a way that a deviation between an output signal and the parameterized wave function is minimized. Furthermore, the phase correction value can be determined as a function of the at least one parameter. Preferably, at least a first phase-specific parameter of a parameterized wave function is determined in such a way that a deviation between the first output signal and the parameterized wave function is minimized. Furthermore, at least one further phase-specific parameter of a parameterized wave function is determined such that a deviation between the further output signal and the parameterized wave function is minimized. Furthermore, the phase correction value can be determined as a function of the at least two phase-specific parameters.

In this case, it is possible that, depending on the parameters of the parameterized wave function, only the explained offset correction value and amplitude correction value can be determined and used for offset and phase correction. Then, depending on the thus corrected output signals, a phase correction can be performed.

This also results in a reliable and sufficiently accurate determination of correction values.

In a further embodiment, the measuring device is a displacement measuring device or an angle measuring device. This has already been explained above.

In a further embodiment, the phase correction is performed independently of a partial region of the measuring range. In other words, the same phase correction can be performed for the entire measurement range. In particular, exactly one global phase correction value can be calculated for the entire measuring range, with a phase position of at least one of the output signals being corrected in / over the entire measuring range as a function of this global phase correction value.

Also, an amplitude and / or an offset correction can be carried out independently of a subregion of the measuring region. In other words, the same amplitude and / or offset correction can be performed for the entire measuring range. Thus, precisely one global offset correction value and / or one global amplitude correction value can be determined for the entire measurement range for each output signal, the corresponding output signal being corrected over the entire measurement range as a function of precisely this one global offset correction value and / or global amplitude correction value.

In a preferred embodiment, however, a measuring range of the measuring device is subdivided into at least two, but preferably into more than two, subregions. Furthermore, a subrange specific phase correction is performed. Of course, also a partial area specific offset and / or amplitude correction can be performed. In other words, sub-region specific corrections are performed for output signals generated in different subregions of the measuring range. A partial area may in this case comprise a section of the measuring device having at least one period length. In other words, a portion of the measuring range may include a range in which at least one period of an output signal is generated when the at least one detecting device is moved in a constant moving direction along the portion. However, a partial area preferably comprises a plurality of period lengths or a plurality of periods of the output signal are generated during the method along the partial area.

It is possible that different offset and / or amplitude and / or phase errors occur in different subregions of the measuring range. For example, an assembly of the measuring device can take place in such a way that different offset and / or amplitude values are generated in different partial regions, for example due to an uneven mounting support for the measuring device.

Through the described partial range-specific correction of output signals, a more accurate and improved signal correction can then take place over the entire measuring range, wherein an improved position determination is furthermore made possible over the entire measuring range.

It is possible, for example, for the output signals to be generated and stored over the entire measuring range in a calibration step, which can take place, for example, before the measuring device is put into operation. In this case, a distance from interpolation points at which the output signals are detected may be less than or equal to 1/20 of a period length.

Furthermore, at least two, preferably more than two, subareas of the measuring range can be determined. These sections may differ from each other. However, it is possible that consecutive subareas overlap along the measurement area. Alternatively, it is possible that mutually different partial regions adjoin one another directly along a constant direction of movement through the measuring region.

Furthermore, the progressions of the first and further output signals in each of these subareas can be determined.

As previously explained, a phase correction value and optionally also a signal-specific amplitude and / or offset correction value can then be determined and stored for each subarea, in particular as a function of the signal courses in the respective subarea.

Then, in particular at runtime, a partial area-specific phase correction in dependence on the stored partial area-specific phase correction value, a phase correction can be performed. Also, in particular at runtime, a partial range and signal-specific amplitude and / or offset correction can be carried out as a function of the stored partial range-specific correction value / correction values.

Furthermore, a subrange specific phase correction value can be calculated for each subrange. This can be calculated as a function of the signal curves in this subarea. Furthermore, in the subarea a phase angle of at least one of the output signals can be corrected as a function of the subrange specific phase correction value.

It is also possible to determine a partial area and signal-specific offset correction value and / or a partial area and signal-specific amplitude correction value for each partial area. Furthermore, the corresponding signal can be corrected as a function of the partial area and signal-specific offset correction value and / or as a function of the partial area and signal-specific amplitude correction value.

It is e.g. it is possible for partial area-specific phase correction values to be determined and stored in the explained calibration step, for example in a memory device of the measuring device. Partial and signal-specific amplitude and / or offset correction values can also be determined and stored. Then, especially at runtime, a current subarea can be identified. The current subarea can designate a subarea of the measuring range in which the measuring device is currently located. Furthermore, the partial area-specific correction values can then be called up and a signal correction can be carried out as a function of the retrieved correction values.

Alternatively, it is possible to determine a partial area-specific phase correction value at runtime and then to perform a corresponding phase correction. Of course, it is also possible to determine partial range and signal-specific offset and / or amplitude correction values at runtime and then to carry out a corresponding signal correction.

This results in an advantageous manner for each sub-area computationally simple and thus quickly feasible signal correction.

In a further embodiment, a subarea of the measuring range is identified as a function of at least one uncorrected output signal. In this case, the at least one uncorrected output signal can be used to determine a position of the measuring device, it being possible for the partial region to be identified as a function of the position. If, for example, a distance traveled is determined as a function of the output signal, a current position of the measuring device can be determined as a function of the distance traveled. For example, a last determined position of the Measuring device are stored, wherein the current position is then determined depending on the last determined position and the value traveled, for example, as the sum thereof.

In an alternative embodiment, a partial area of the measuring area is identified as a function of at least one corrected output signal. In this case, the at least one corrected output signal can be used to identify the subarea, as explained above.

Further proposed is a device for correcting at least one output signal of a measuring device. The device serves to carry out a method according to one of the embodiments explained in this disclosure.

In particular, therefore, the device is designed such that a corresponding method by means of the device is feasible. The device may be part of a measuring device comprising the measuring device and the proposed device for correction.

In this case, the measuring device generates a first wave-shaped output signal and at least one further wave-shaped output signal. This has already been explained above.

The device comprises a signal interface for the first output signal of the measuring device and a signal interface for the further output signal of the measuring device. Furthermore, the device comprises at least one phase correction device. The phase correction device may in this case comprise a microcontroller or be designed as such. Furthermore, the phase correction device may comprise a memory device. Furthermore, as will be explained in more detail below, the phase correction device may comprise arithmetic operation means, for example a multiplication means, a divisional means, an addition means and / or a subtraction means. By a computing operation means a predetermined arithmetic operation is feasible.

Furthermore, a profile of the first and the further output signal can be detected over at least one period of the first output signal and / or of the further output signal. Furthermore, depending on the first output signal and the further output signal, a phase correction of the first and / or of the further output signal can be carried out, in particular by means of the phase correction device.

According to the invention, a phase correction value can be determined or calculated, in particular by means of the phase correction device. Furthermore, the phase correction value can be determined as a function of an amplitude characteristic of the first and the further output signal over at least one period of one of the output signals, in particular by means of the phase correction device. Furthermore, a phase position of at least one of the output signals can be corrected as a function of the phase correction value, in particular by means of the phase correction device.

The device may further include signal interfaces for the corrected output signals. Via these signal interfaces, corrected output signals for a position-determining device can be provided.

In this case, the phase correction device may comprise at least one means for calculating the phase correction value. Furthermore, the phase correction device may comprise a memory device for storing the at least one phase correction value. This and corresponding advantages have already been explained above.

In a further embodiment, the phase correction device comprises at least one means for determining a sine value of the phase correction value, a means for determining a cosine value of the phase correction value, a dividing means, a multiplication means and a subtraction means. In this case, as previously explained, the phase-corrected first output signal can advantageously be determined by the individual means.

An embodiment in which the phase correction device comprises at least one multiplication means and one subtraction means is also described. In this case, as previously explained, a good approximation of the phase-corrected first output signal can advantageously be determined.

Alternatively, the phase correction means may also comprise all necessary means for determining a phase-corrected further output signal or an approximated further output signal.

In a further embodiment, the device further comprises at least one amplitude correction device and / or at least one offset correction device. By means of the amplitude correction means, an amplitude correction can be performed. By means of the offset correction device, an offset correction can be carried out. The amplitude correction device and / or the offset correction device can also be designed as a microcontroller or comprise such. This and corresponding advantages have already been explained above.

Furthermore, the device may comprise at least one device for identifying a partial area of the measuring area. By means of the device, a partial area can be identified, as a result of which a partial area-specific signal correction, in particular a partial area-specific phase correction, is made possible. This and corresponding advantages have already been explained above.

In this case, a plurality of phase correction values and, in particular, partial range and signal specific amplitude and / or offset correction values can be stored in the memory device.

A method of correction according to one of the embodiments explained in this disclosure may be, in particular, a computer-implemented method.

Further described is a data processing device comprising means for carrying out the method according to one of the embodiments explained in this disclosure. In particular, the apparatus may include a processor configured to execute a method according to one of the embodiments discussed in this disclosure.

Further described is a computer program product and / or a computer-readable storage medium, in particular a data carrier, comprising instructions which, during the execution of the program by a computer, cause it to carry out the method according to an embodiment explained in this disclosure.

• 1 ein schematisches Blockschaltbild einer erfindungsgemäßen Vorrichtung in einer ersten Ausführungsform,
• 2 ein schematisches Blockschaltbild einer erfindungsgemäßen Vorrichtung in einer weiteren Ausführungsform,
• 3 ein schematisches Blockschaltbild einer erfindungsgemäßen Vorrichtung in einer weiteren Ausführungsform,
• 4 ein schematisches Diagramm eines erfindungsgemäßen Verfahrens,
• 5 ein schematisches Flussdiagramm eines erfindungsgemäßen Verfahrens in einer weiteren Ausführungsform und
• 6 eine schematische Darstellung von Signalverläufen.

The invention will be explained in more detail with reference to an embodiment. The figures show:

• 1 1 is a schematic block diagram of a device according to the invention in a first embodiment,
• 2 a schematic block diagram of a device according to the invention in a further embodiment,
• 3 a schematic block diagram of a device according to the invention in a further embodiment,
• 4 a schematic diagram of a method according to the invention,
• 5 a schematic flow diagram of a method according to the invention in a further embodiment and
• 6 a schematic representation of signal waveforms.

Hereinafter, like reference numerals designate elements having the same or similar technical features.

1 shows a schematic block diagram of a device according to the invention 1 for correcting at least one output signal A . B a measuring device 2 , The measuring device 2 is a displacement measuring device, which is a line measuring tape 3 and two detectors 4A . 4B includes. By the detection device 4A . 4B are in dependence of an arrangement of lines on the line scale 3 Output signals A, B can be generated. In particular, in the process of detecting means generates 4A , 4B along the line of measurement 3 with a constant direction of movement, a first detection device 4a a first wave-shaped output signal A and another detection device 4B another wave-shaped output signal B , These output signals have a phase offset of approximately 90 ° to each other.

The detection devices 4A . 4B may be, for example, optical sensors, the waveform of the output signals A . B is generated in response to a detected radiation intensity, which in turn depends on the arrangement of the lines on the line scale 3 is.

The measuring device 2 but can also be an angle measuring device. In this case, the line measuring tape can be disc-shaped or hollow-ring-shaped, wherein lines are arranged along a circular line.

The device 1 includes a signal interface 5A for the first output signal A and a signal interface 5B for the further output signal B , By arrows are in 1 and shown in the other block diagrams data and / or signaling connections.

Furthermore, the device comprises 1 a phase correcting device 6 ,

Furthermore, the device comprises 1 a first offset correction device 7A , another offset correction device 7B , a first amplitude correction device 8A and another amplitude correction device 8B ,

By means of the first offset correction device 7A is an offset correction for the first output signal A feasible. In particular, the offset correction can be carried out such that the offset-corrected first output signal A has an offset value of 0. Next is by means of the first amplitude correction means 8A an amplitude correction of the offset-corrected first output signal A feasible. In particular, this amplitude correction can be carried out such that an amplitude of the offset-corrected first output signal to the value 1 or normalized to a predetermined value adapted to an A / D converter. The illustrated sequence of corrections is only an example. Of course, an offset correction of an amplitude-corrected first output signal A be performed. Corresponding corrections are made by the correction devices 7B . 8B for the further output signal B feasible.

In particular, amplitude and offset correction values can be determined numerically, in particular as a function of at least one parameter of a parameterized elliptical equation, wherein the at least one parameter is determined in such a way that a deviation of points of a set of points from the ellipse, which is described by the ellipse equation, is minimized if the first output signal is an abscissa value and the further output signal is an ordinate value of the points of the set of points. Alternatively, amplitude and offset correction values can be determined in dependence on parameters of a parameterized wave function, these parameters being determined in such a way that a deviation between an output signal and the parameterized wave function is minimized. This has already been explained above.

Depending on the offset- and amplitude-corrected first output signal A and the offset and amplitude corrected further output signal B is through the phase corrector 6 a phase correction of the first and / or the further output signal A . B feasible. Here, as will be explained in more detail below, a phase correction value for a phase shift between the first and the further output signal A . B calculated, this phase correction value in response to a waveform of the first and the further output signal A . B over at least one period of one of the output signals A . B is determined. Furthermore, the phase position of at least one of the output signals, in particular the phase position of the first output signal A corrected according to the phase correction value.

Also shown are output signal interfaces 9A . 9B for the offset-, amplitude- and phase-corrected output signals.

In particular, by means of the phase correction device 6 an amount of the phase correction value may be determined. For this purpose, a summation profile of a sum of the squared signal value of the offset- and amplitude-corrected first output signal and of the squared signal value of the offset- and amplitude-corrected further output signal can be determined if the detection devices 4A . 4B along at least one period of the line scale 3 be moved with a constant direction of movement. Furthermore, a maximum value and a minimum value of this summation profile can be determined. Then, according to formula 5, the phase correction value can be determined. A sign of the phase correction value can be determined as a function of a summation profile of a sum of the signal value of the offset- and amplitude-corrected first output signal and the signal value of the offset- and amplitude-corrected further output signal. In particular, a maximum value of this summation profile can be determined, and a sign of the phase correction value can be determined by the previously described case distinction.

Alternatively, the phase correction value can be determined as a function of at least one parameter of a parameterized elliptic equation. In this case, the at least one parameter, in particular by an optimization method, more particularly a numerical optimization method, is determined in such a way that a deviation of points of a set of points from the ellipse, which is described by the ellipse equation, is minimized. An abscissa value of a point is determined here as a signal value of the first output signal and an ordinate value of the point as a signal value of the corresponding further output signal. If the output signals are detected for a period of at least one output signal, then a set of points having a plurality of points can be determined.

Furthermore, the points of the set of points thus determined are rotationally transformed, in particular by multiplication with a rotary matrix which causes a rotation through 45 ° about a rotation axis perpendicular to the ordinate and abscissa.

Furthermore, the at least one parameter is determined such that a deviation of points of this rotationally transformed set of points from the ellipse, which is described by the ellipse equation, is minimized. As a function of this at least one ellipse parameter, a phase correction value is then determined.

After that, one of the signals, in particular the first output signal, can be shifted by this phase correction value. For this purpose, a phase-corrected output signal can be calculated as a function of the corresponding output signal, which is phase-shifted relative to the corresponding output signal by the phase correction value.

This makes it possible to correct signal waveforms for the first and / or the further output signal A . B to determine the reliable and accurate positioning in response to the corrected output signals A . B enable.

In this case, the phase correction value in dependence on the offset and amplitude-corrected first output signal A and the offset and amplitude corrected further output signal B certainly. However, it is also possible to determine the phase correction value as a function of a non-offset-corrected output signal and / or a non-amplitude-corrected output signal.

In 1 It is shown that the amplitude and offset correction for the first output signal A independent of the further output signal B is carried out. The amplitude and offset correction for the further output signal B will be independent of the first output signal A carried out.

2 shows a schematic block diagram of a device according to the invention 1 in a further embodiment. The device is here according to the in 1 formed embodiment illustrated. Therefore, please refer to the explanation in this regard 1 directed. Unlike the in 1 illustrated embodiment performs the offset correction device 7 an offset correction of both output signals A . B by. For this purpose, the offset correction device 7 depending on the two output signals, in particular of signal waveforms of both output signals over at least one period of an output signal, in each case determine a signal-specific offset correction value and then offset-corrected output signals as a function of this correction value A . B determine.

An amplitude correction device 8th may be dependent on the offset-corrected output signals for each of the output signals A . B in each case determine an amplitude correction value and then perform an amplitude correction as a function of the signal-specific correction value.

In particular, therefore, the amplitude and offset correction of the further output signal B also in dependence on the first output signal A and the amplitude and offset correction of the first output signal A also in dependence on the further output signal B carried out.

3 shows a schematic block diagram of a device according to the invention 1 in a further embodiment.

Unlike the in 1 In the embodiment shown, several subregions TBn-1, TBn, TBn + 1 of the measuring range are shown. In the present case, the subregions TBn-1, TBn, TBn + 1 are subsections of the line scale 3 educated. In this case, the detection devices generate 4A . 4B at least one, preferably several periods of the output signals A . B if they are with a constant Moving direction can be moved over one of the subregions TBn-1, TBn, TBn + 1. In a subregion TBn-1, TBn, TBn + 1, signal values of the output signals A, B can be detected at a predetermined number of interpolation points.

Unlike the in 1 illustrated embodiment, the offset and amplitude correction means 7A . 8A summarized in a block. In this block, depending on the first output signal A for example, a partial area-specific offset correction value and a partial area-specific amplitude correction value for the first output signal A certainly. By dashed lines is shown that such an offset and amplitude correction value also in dependence on the other output signal B can be determined.

Accordingly, the offset correction device 7B and the amplitude correction device 8B for the further output signal B summarized in a block. This can have a signal-specific and subrange-specific offset correction value and a signal-specific and subrange-specific amplitude correction value for the further output signal B depending on the uncorrected further output signal B determine. Dashed lines show that these correction values are also dependent on the first output signal A can be determined.

Next is shown that the first output signal A and the further output signal B through the corresponding correction means 7A . 8A offset and amplitude corrected.

A phase corrector 6 includes a computing device 10 , which depend on the offset and amplitude-corrected first output signal A and the offset and amplitude corrected further output signal B determines a subrange specific phase correction value. This can be determined depending on signal characteristics. Alternatively, the phase correction value may be from a memory device 18C , which will be explained below, are read out.

Furthermore, the phase correction device comprises 6 a sine member 11 which determines a sine value of the subrange specific phase correction value. Furthermore, the phase correction device comprises a multiplication element 12 which outputs the amplitude and offset corrected further output signal B multiplied by the sine value of the subrange specific phase correction value. Furthermore, the phase correction device comprises 6 a subtraction element 13 showing the illustrated product from the first offset and amplitude corrected first output signal A withdraws. Further, this difference is multiplied by the reciprocal of the cosine value of the subrange specific phase correction value. For this purpose, the phase correction device comprises a cosine element 14 and a divisional member 15 as well as another multiplication element 16 ,

It is possible to use the phase correcting device 6 also without sinusoidal link 11 , Cosine member 12, the division member 15 and the multiplier 16 train. In this alternative case, the phase corrector 6 the multiplier 12 comprising the amplitude and offset corrected further output signal B multiplied by the subrange specific phase correction value. Furthermore, the phase correction device comprises 6 a subtraction element 13 showing the illustrated product from the first offset and amplitude corrected first output signal A withdraws. Further, this difference forms the offset, amplitude and phase corrected first output signal A ,

It is possible that the in 1 and 2 illustrated phase correcting device 6 according to the in 3 shown phase correction device 6 are formed, wherein instead of the partial area-specific phase correction value, a non-partial area-specific, valid for the entire measuring range, phase correction value is determined.

It is still possible at the in 1 to 3 illustrated embodiments, an offset correction value, an amplitude correction value and a phase correction value to determine at run time, so for example when a measurement passage is performed. In this case, subrange specific correction values can be determined for the subrange TBn-1, TBn, TBn + 1 in which the output signals A . B are generated, depending on these output signals A . B then the correction values are determined and then a signal correction is performed as a function of these partial range-specific correction values. Furthermore, it may be possible for signal values of the output signals A , B, to determine the subrange specific correction values. This can be done in not shown latching means of the correction means 7A, 7B, 8A, 8B, 6. However, no storage of the correction values is necessary.

However, it is also possible to set the partial range-specific correction values before commissioning the measuring device 2 to determine and store, for example in a calibration passage. Of course, the correction values determined at runtime, as explained above, can also be stored.

In 3 It is shown that the first offset and amplitude correction device 7A . 8A a storage device 18A and the further offset and amplitude correction means 7B, 8B a memory means 18B and the phase corrector 6 a storage device 18C includes, wherein the memory devices 18A . 18B . 18C for storing the signal- and subrange-specific offset correction values which serve signal and subrange specific amplitude correction values as well as the subrange specific phase correction values.

Furthermore, at runtime, ie in a measuring operation, the current subarea TBn-1, TBn, TBn + 1 can then be identified, for example as a function of uncorrected or corrected output signals. The corresponding subrange specific correction values can then be read during runtime and used for correction. This eliminates the determination of the corresponding correction values at runtime. This can be done faster signal processing.

However, as in the 1 and 2 If no partial range-specific, but global correction values are used for signal correction over the entire measuring range, then the memory devices can 18A . 18B . 18C are used for storing the global signal-specific offset correction values, the global signal-specific amplitude correction values and the global phase correction value. In this case, the global correction values can be read in during runtime and used for correction.

In 4 is shown a schematic flow diagram of a method according to the invention. In a first step S1 become the ones of the measuring device 2 (see eg 1 ), in particular of the detection devices 4A . 4B , generated output signals A . B read, in particular via corresponding signal interfaces 5A, 5B.

In a second step S2 then becomes dependent on the two uncorrected output signals A . B a signal-specific offset correction value and a signal-specific amplitude correction value are determined or read from a memory device 18A, 18B, 18C and the signals A . B as a function of these correction values offset and amplitude corrected.

In a third step S3 is dependent on the two offset- and amplitude-corrected output signals A . B calculates a phase correction value.

Alternatively, an already determined phase correction value, in particular a partial range-specific phase correction value, can also be obtained from a memory device 18C be read.

Next a phase of an output signal A . B , in particular the first output signal A corrected by calculating a phase-corrected first output signal. A dashed line shows that the sequence of steps, the second and the third step S2 . S3 includes, multiple times, for example, twice or three times, can be performed. In a fourth step S4 the corrected output signals are output.

If the correction values used, for example the offset and amplitude correction values as well as the phase correction value, have been previously known, for example in a calibration run or at an earlier time during measurement operation, then these can be used in the second and in the third step S2 . S3 be read, for example, from a memory device 18A . 18B . 18C , in which case a signal correction is carried out as a function of the read-in correction values. In this case, therefore, no determination of the correction values takes place at runtime. However, it is also possible for the correction values to be determined at runtime, ie during or for the execution of the second and the third step.

In 5 is a schematic flow diagram of a method according to the invention shown in a further embodiment. Unlike the in 4 illustrated embodiment is in this case between the first and the second step S1 . S2 in an intermediate step S1a a subrange of the measuring range is identified. In the second and in the third step S2 . S3 then sub-area specific correction values from a memory device 11 read in and a corresponding signal correction, in particular a partial area specific phase correction performed.

6 shows a schematic representation of signal waveforms. In the first line are waveforms of the first and the further output signal A . B (see eg 1 ), wherein a phase shift between the first and the further output signal A . B deviates by -50 ° from 90 °. In the second line is a waveform of the two output signals A . B for a phase shift that deviates by -10 ° from the ideal phase shift of 90 °. In the third line is a waveform of the two output signals A . B represented, which corresponds to the ideal waveform. In the fourth line is a waveform of the two output signals A . B which deviates by + 10 ° from the ideal phase shift of 90 °.

Here, in the first column, the waveforms for a period of the two output signals A . B shown, in particular when the detection devices 4A . 4B by one bar period along a constant direction along the tape measure 3 to be moved. It is shown that the detected output signals A . B already offset and amplitude corrected.

Elliptical representations of the waveforms are shown in the second column, with the values of the first output signal A Abscissa values and corresponding values of the further output signal B Form ordinate values of points. In the third column is a summation profile of the respective squared signal values of the first output signal A and the further output signal B shown.

It can be seen that for phase shifts which deviate by a negative value from the ideal phase shift of 90 °, the first main axis HA1 of the corresponding ellipse representation (FIG. 2 , Column) through the first and third quadrant. The larger this absolute deviation from the ideal phase shift, the slimmer the ellipse, that is, the greater a ratio between the length of the first main axis HA1 and the second main axis HA2. If the ideal phase shift of 90 ° is given, a circular shape is given if the output signals are plotted as abscissa value and ordinate value, respectively.

In the case of a positive deviation from the ideal phase shift of 90 °, the first major axis HA1 of the elliptical shape extends through the second and fourth quadrants.

Simulations have shown that the proposed method enables an accurate, reliable and temporally fast determination of a phase correction value and optionally also of an amplitude and offset correction value.

LIST OF REFERENCE NUMBERS

1

Device for correction

2

measuring device

3

stroke measuring tape

4A, 4B

detection devices

5A, 5B

Signal interfaces

6

Phase corrector

7, 7A, 7B

Offset correction facilities

8, 8A, 8B

Amplitude correction facilities

9A, 9B

Signal interfaces

10

computing device

11

sinus link

12

multiplication element

13

subtraction

14

Kosinusglied

15

division element

16

multiplication element

18A

memory device

18B

memory device

18C

memory device

S1

first step

S2

second step

S3

Third step

S4

fourth step

S1a

intermediate step

A

first output signal

B

another output signal

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10036090 A1 [0019]
• DE 102004038621 B3 [0020]
• DE 10163504 A1 [0021]
• DE 19914447 A1 [0022]

Claims (17)

Method for correcting at least one output signal (A, B) of a measuring device (2), wherein the measuring device (2) generates a first wave-shaped output signal (A) and at least one further wave-shaped output signal (B), characterized in that a phase correction value depends on a Waveform of the first and the further output signal (A, B) over at least one period of one of the output signals (A, B) is determined or calculated, wherein a phase position of at least one of the output signals is corrected in response to the phase correction value. Method according to Claim 1 , characterized in that an amount of the phase correction value is determined in dependence on a curve of a sum of the squared signal value of the first output signal (A) and the squared signal value of the further output signal (B). Method according to Claim 2 , characterized in that the amount of the phase correction value is determined in dependence on a maximum value of the course of the sum and a minimum value of the course of the sum. Method according to one of Claims 1 to 3 , characterized in that a sign of the phase correction value is determined as a function of a curve of a sum of the signal value of the first output signal and the signal value of the further output signal. Method according to Claim 4 , characterized in that the sign is determined in dependence on a maximum value of the course. Method according to Claim 1 characterized in that the phase correction value is determined in dependence on at least one parameter of a parameterized elliptical equation, wherein the at least one parameter is determined such that a deviation of points of a set of points from the ellipse described by the ellipse equation is minimized when an abscissa value of a point of the set of points in dependence on the first output signal and an ordinate value of the point in dependence on the corresponding further output signal is determined. Method according to one of Claims 1 to 6 characterized in that a phase-corrected first output signal (A) is determined by forming a difference between the phase-corrected first output signal (A) and a phase-corrected further output signal (B) multiplied by the sine value of the phase correction value and dividing by a cosine value of the phase correction value. Method according to one of the preceding claims, characterized in that additionally carried out an offset correction of the first output signal (A) and / or the further output signal (B) and / or an amplitude correction of the first output signal (A) and / or the further output signal (B) becomes. Method according to Claim 8 , characterized in that for each of the first and the further output signal (A, B) at least one signal-specific offset correction value and / or at least one signal-specific amplitude correction value is determined, wherein the first and the further output signal (A, B) in each case depending on the signal-specific offset and amplitude correction values are corrected. Method according to Claim 9 , characterized in that the at least one offset correction value and / or the at least one amplitude correction value is / are determined numerically. Method according to Claim 10 , characterized in that the at least one offset correction value and / or the at least one amplitude correction value is determined as a function of at least one parameter of a parameterized elliptic equation, wherein the at least one parameter is determined such that a deviation of points of a set of points from the ellipse passing through the elliptic equation is minimized when an abscissa value of a point of the set of points in dependence on the first output signal and an ordinate value of the point in dependence on the corresponding further output signal is determined or at least one parameter of a parameterized wavefunction is determined such that a deviation between a Output signal and the parameterized wave function is minimized, wherein the at least one offset correction value and / or the at least one amplitude correction value is determined as a function of the at least one parameter. Method according to one of the preceding claims, characterized in that the phase correction is performed independently of a portion of the measuring range. Method according to one of Claims 1 to 11 , characterized in that a measuring range of the measuring device (2) is subdivided into at least two subregions, wherein a subrange specific phase correction is performed. Method according to Claim 13 , characterized in that a portion of the measuring range in response to at least one uncorrected output signal (A, B) or in dependence on at least one corrected output signal (A, B) is identified. Device for correcting at least one output signal (A, B) of a measuring device (2), wherein the measuring device (2) generates a first wave-shaped output signal (A) and at least one further wave-shaped output signal (B), wherein the device (1) has a signal interface ( 5A) for the first output signal (A) of the measuring device (2) and a signal interface (5B) for the further output signal (B) of the measuring device (2), wherein the device (1) comprises at least one phase correcting device (6), characterized in that a phase correction value can be determined as a function of a signal curve of the first and further output signals (A, B) over at least one period of one of the output signals (A, B), wherein a phase position of at least one of the output signals (A, B) as a function of the phase correction value is corrected. Device after Claim 15 , characterized in that the phase correction means (6) comprises at least one means for determining a sine value of the phase correction value, a means for determining a cosine value of the phase correction value, a dividing means, at least one multiplication means and a difference forming means. Device after Claim 15 or 16 , characterized in that the device (1) further comprises at least one amplitude correction device (8, 8A, 8B) and / or at least one offset correction device (7, 7A, 7B).

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