DE102022111845B3 - calibration aid - Google Patents

Abstract

The invention relates to a calibration device (11) for calibrating an inertial measuring sensor system (4) of an electronic pen (1), comprising: a housing (12) for receiving an electronic pen (1), and wherein the housing (12) has at least one holding means ( 6, 7) for fixing an electronic pen (1) accommodated in the housing (12).

Description

State of the art

The invention relates to a device for calibrating an inertial measuring sensor of an electronic pen, a method for calibrating an inertial measuring sensor of an electronic pen and a system comprising an electronic pen and a device for calibrating an inertial measuring sensor of the electronic pen.

When the movements and positions of an electronic pen are recorded by inertial measuring systems, such as acceleration sensors or yaw rate sensors, the data from these sensors must be integrated once or twice in order to generate a speed signal or angle signal (first integration) or a location signal (second integration) of the obtain an electronic pen. Small errors in the measurements of accelerations and/or angular velocities by the inertial measuring sensors of the electronic pen can lead to larger errors in the determination of the velocity during the first integration, which in turn lead to even larger errors in the position signal, which increase quadratically over time after integration of the Speed signal can lead.

Since, for example, a new position of the electronic pen is determined starting from a previously determined determined position, errors in the speed determination and location determination of the electronic pen can continue to accumulate.

In addition to inherent inaccuracies in numerical integration methods, possible sources of error can also include inaccuracies in analog-to-digital conversions of measurement sensor signals, zero point errors, e.g. due to poor calibration of the measurement sensors, random interference or system-inherent noise components.

In particular, zero-point errors in inertial measuring sensors in known electronic pens that are not calibrated or only insufficiently precisely calibrated, such as zero-point errors in signals from acceleration sensors in known electronic pens that are not calibrated or only imprecisely, can add up over time in an undesirable manner and reduce the accuracy with which the position and the movement of an electronic pen can be determined.

Examples of known methods for calibrating the sensors of electronic pens are, among others, in US 2016/0026362 A1 , in the CN 112148139A and in the KR 10 2021 0 014 303 A described.

Task

It is therefore the object of the invention to provide means which enable a simplified and/or improved calibration of an inertial measuring sensor system of an electronic pen, in particular an improved calibration of acceleration sensors of an electronic pen.

Solution

According to the invention, this is achieved by a calibration device for calibrating an inertial measuring sensor system of an electronic pen according to claim 1, by a method for calibrating an inertial measuring sensor system of an electronic pen according to the independent method claim and by a system according to the independent system claim, comprising a device for calibrating an inertial measuring sensor system an electronic pen and an electronic pen.

Advantageous embodiments and developments are the subject of the dependent claims.

An exemplary device for calibrating an inertial measuring sensor system of an electronic pen can include a housing for holding an electronic pen, wherein the housing can have at least one holding means for fixing an electronic pen held by the housing.

An inertial measuring sensor system of an electronic pen can be understood here in particular to mean that the measuring sensor system includes acceleration sensors, eg at least one three-dimensional acceleration sensor that can measure accelerations along three mutually orthogonal spatial axes of a three-dimensional inertial measuring system. Said spatial axes of the acceleration sensor/measuring sensor system that are orthogonal to one another can also be referred to as sensor axes.

In addition, the inertial measuring sensor system of an electronic pen can comprise at least one yaw rate sensor, e.g. a three-dimensional yaw rate sensor, which can, for example, measure rotations about the axes of said three-dimensional inertial measuring system.

The exemplary inertial measuring sensor system of an exemplary electronic pen can be configured/arranged in such a way that the exemplary three-dimensional inertial measuring system with three mutually orthogonal spatial axes/sensor axes, in which accelerations and/or yaw rates can be measured, can be oriented in such a way that a spatial axis of the inertial measurement system or a sensor axis is parallel to the longitudinal axis of the electronic pen or coincides with the longitudinal axis of the electronic pen, or that a spatial axis of the inertial measurement system or a sensor axis is not parallel or only approximately parallel to the longitudinal axis of the electronic pen. Any undesired or unintended deviations found in the alignment of sensor axes in relation to the longitudinal axis of the electronic pen can be corrected or compensated for by a corresponding calibration.

An electronic pen can be understood here, for example, to mean, for example, that the electronic pen has, for example, at least one electrical voltage source and one or more electronic components that can be supplied by the voltage source, such as a digital control unit or a digital computing unit with one or more processors, as well as at least one communication module for receiving and transmitting data and instructions.

Among other things, electronic pens have the advantage that they can combine the functionality and simplicity of writing with a pen on a surface with the diverse possibilities of electronic data processing, since what is written can be converted directly into an electronic data processing format.

Fixing an electronic pen accommodated in the housing can be understood, among other things, to mean that the electronic pen can be fixed in a predeterminable alignment or orientation in the housing, i.e. can be arranged firmly in a predeterminable alignment or predeterminable orientation or predeterminable position .

Surprisingly, it was found that such a device, in which an electronic pen is fixed in said device housing, enables a more precise calibration of the zero points of the inertial measuring sensors of an electronic pen, in particular a more precise calibration of the zero points of the acceleration sensors of an electronic pen, without one requires exact alignment along the axes of the earth-fixed coordinate system.

In particular, it was surprisingly found that during a calibration process of the inertial measuring sensor system of the electronic pen, in which the inertial measuring sensor system is rotated about at least one axis or a spatial axis of a/the three-dimensional inertial measuring system of the inertial measuring sensor system and in which measurement data from the inertial measuring sensor system are recorded at several rotational positions, in particular measurement data or acceleration signal data of the acceleration sensors / of the acceleration sensor, are recorded, the measurement data, in particular the acceleration signal data of the acceleration sensors / of the acceleration sensor, are almost free of noise if during said calibration process, i.e. during said rotation of the inertial measuring sensor system, the electronic pen in a calibration device described herein is fixed, so that when the calibration device described herein rotates, the electronic pen, together with its inertial measuring sensor system, also rotates in a well-defined manner.

In addition, rotating the electronic pen using the calibration device with predeterminable rotational positions, i.e. rotations about predeterminable known angles, can also enable the calibration of yaw rate sensors of the inertial measuring sensor system, i.e. the calibration of the scale values of yaw rate sensors.

For example, by holding the position of the electronic pen using the calibration device described here as an example in a predeterminable rest position for a predeterminable period of time, e.g. in the order of seconds or shorter, measured values in the axes of the yaw rate sensors can be recorded and averaged around zero points in the axes of the rotation rate sensors.

The axes of the yaw rate sensors can then be scaled from subsequent rotations of the electronic pen by means of the calibration device described here by way of example around predeterminable known rotation angles/rotational positions/rotational angle positions.

The at least one holding means of the calibration device is configured in such a way that a received electronic pen can be fixed or fixed in the middle or centered within the housing or centered within the calibration device.

In addition, the at least one holding means of the calibration device can be configured in such a way that it can fix a received electronic pen in a position/orientation/orientation in the housing such that the/a longitudinal axis of a/the received electronic pen is at least approximately aligned with an axis, e.g the / a longitudinal axis of the housing can collapse.

Such a fixation of a received electronic pen within the housing of the calibration device can further reduce the noise in the measurement data of the inertial measurement sensor system of the electronic pen, in particular the noise in acceleration measurement values from at least one acceleration sensor of the inertial measurement sensor system, and thus an even more precise calibration of the inertial Enable measurement sensors.

Above all, such a fixation simplifies more precise holding of the received electronic pen in predeterminable angular positions or in predeterminable spatial alignments/orientations.

For example, the calibration device described here as an example can make it possible to rotate the recorded electronic pen by exactly 180° between the recording of measurement data from the inertial measurement sensor system, so that possible errors in orientation, e.g. possible angle errors in the alignment of the electronic pen to axes, e.g. Main axes, the calibration device, cancel each other out when determining zero point errors.

The at least one holding means is configured to fix a received electronic pen in such a way that the longitudinal axis of the received electronic pen is oriented at least approximately parallel to the longitudinal axis of the housing.

In such a configuration of the at least one holding means, the noise in measured acceleration values from at least one acceleration sensor of the inertial measuring sensor system of the electronic pen is significantly reduced compared to a calibration process without using the calibration device.

For the sake of completeness, it should be noted that e.g. a/the longitudinal axis of the electronic pen can be defined or selected in such a way that the writing tip or writing tip of the electronic pen can lie on the longitudinal axis of the electronic pen.

The cross section of the housing of the calibration device is rotationally symmetrical and/or cylindrical or polygonal, e.g. rectangular.

For example, the housing of the calibration device can be tubular.

Alternatively, the housing of the calibration device is designed, for example, in the form of a cube or cuboid. For example, the housing of the calibration device can also serve as a packaging carton/packaging box.

A rotationally symmetrical, for example a cylindrical or tubular cross-sectional profile, in particular a circular-cylindrical cross-sectional profile of the housing of the calibration device, can facilitate, among other things, a more uniform turning of the calibration device, which also reduces noise in acceleration measured values from at least one acceleration sensor of the inertial measuring sensor system.

A polygonal cross-section or a polygonal or cuboid cross-sectional profile of the housing of the calibration device can make it easier, among other things, to set and run through a well-defined sequence of rotation positions/rotation angle/rotation angle positions of the calibration device when the calibration device is rotated with the electronic pen attached.

In this case, for example, an integer multiple can be selected for the number of side surfaces of the housing of the calibration device, which, among other things, simplifies the evaluation of the measurement data of the inertial measurement sensors, which can be recorded at the angle of rotation/rotational angle positions of the calibration device defined by the various side surfaces, since a well-defined sequence of measurement data can be obtained.

The rotation of the calibration device with the electronic pen can be carried out freely in space, e.g. in the air, or preferably on a flat base/flat surface.

Alternatively or additionally, a sequence of measurements over several revolutions can be collected using a/the exemplary calibration device that allows free rotation about an axis, with an evaluation algorithm determining a section of this sequence that includes an integer number of revolutions. The acceleration signal based on the acceleration due to gravity makes it possible to reliably determine the angular position even without prior calibration and thus to determine a specification for the integrated signal of the yaw rate sensor. By using an integral number of revolutions as a basis, a previous calibration of the acceleration sensor can be dispensed with and angular deviations between the axis of the electronic pen and the axis of the yaw rate sensor can be reliably determined.

For the sake of completeness, it should be noted that when turning the calibration device with the electronic pen held in it to carry out a calibration process, the electronic pen or the inertial measuring sensor system of the electronic pen should be switched on/is activated.

The housing of the calibration device can also have different cross sections/different cross-sectional profiles in sections.

For example, it is conceivable that the housing ends have a polygonal cross-sectional profile, while the housing has a different cross-sectional profile between the ends, for example a cylindrical cross-sectional profile.

It is also conceivable that the housing ends have a cylindrical polygonal cross-sectional profile, while the housing between the ends has a different cross-sectional profile, for example a polygonal cross-sectional profile.

The cross-sectional profiles of the ends of the housing can have a larger diameter than the cross-sectional profile of the housing between the housing ends, so that, for example, when the calibration device is rotated on a flat surface, the geometry of the cross-sectional profiles of the ends of the housing determine the traversable/acceptable rotational positions and rotational angles of the calibration device can.

In other words, optionally, for example, the ends of the housing of the calibration device can define the contact surface of the calibration device with a flat base/flat surface.

As already mentioned, the housing of the calibration device can be cubic or cuboid, i.e. it can have six different side surfaces. Such an exemplary six-sided calibration device can then be rotated/tilted one after the other with the electronic pen in a predefinable fixed sequence, so that the calibration device can remain in a rest position on each of its six sides for a predefinable period of time, e.g. a few seconds, in which the inertial measurement sensors can remain measured data can record.

For example, the mean values of the measurement data recorded on opposite sides of the calibration device during the rest position of the calibration device can be used to determine the zero points of the relevant axes and the angular velocity integrated over 180° for scaling said axes.

For example, the zero points of the axes of the rotation rate sensors of the inertial measurement sensor system can be measured/determined in a first rest position, so that they can already be used in the subsequent rotations when the rotation rates are integrated.

For the acceleration sensors, the measurement data recorded on opposite sides of the calibration device can be used to scale the axes that are perpendicular to the side surfaces, and the measurement data in the two orthogonal axes can be used to determine zero points in said orthogonal axes.

The at least one holding means can be flexible. This can be understood to mean, for example, that the holding means can be elastic or that the holding means is at least partially formed/made of a material that can have flexible or elastic material properties.

Furthermore, the holding means can be designed so that it can fill the majority of the interior of the housing of the calibration device, for example more than 50% or more than 75% of the internal volume of the housing of the calibration device.

For example, it is conceivable that the holding means comprises an elastic foam material, e.g. polyurethane, and can be designed, for example, as a foam insert inside the housing of the calibration device, wherein said exemplary foam insert can have a defined cutout for receiving and fixing the electronic pen.

Said exemplary excerpt can therefore have a contour surface complementary to the shape of the electronic pen.

An elastic element inside this cuboid, e.g. a foam insert with a defined cut-out to hold the pen, allows it to be fixed in place.

Alternatively or additionally, it is conceivable that the holding means is designed as a clamping mechanism. For example, it is conceivable that the holding means can be designed as a crown with flexible prongs, with the flexible prongs of the crown being able to clamp and fix the electronic pen.

It is also conceivable, for example, for the crown-like holding means to be integrated in a housing cover of the housing of the calibration device.

The use of polypropylene would be conceivable as an exemplary material for such a clamping mechanism.

Such an optionally possible exemplary embodiment, in which the at least one holding means has flexible or elastic properties, can, among other things, prevent unwanted shocks/vibrations or shocks that can be transmitted to the inertial measuring sensors of the electronic pen held by the calibration device when the calibration device is moved. dampen or weaken.

This can also contribute to a further reduction in noise in the measurement data/measurement signals of the inertial measurement sensors of the electronic pen and thus lead to improved accuracy of the calibration of the inertial measurement sensors.

In particular, comparatively high deflections or peaks in the data from the inertial measurement sensor system, triggered by undesired shocks/vibrations or shocks, can be avoided.

Said deflections or peaks in the data from the inertial measurement sensor system can undesirably impair the accuracy of the calibration, since such peaks or deflections are in the data of the inertial measuring sensors cannot be resolved with sufficient accuracy at a limited measuring frequency.

The at least one holding means can also be configured or designed in such a way that the fixation or attachment of the electronic pen to be held/held in the housing of the calibration device in a definable spatial alignment or orientation via a detachable connection, e.g. via clamps and / or screwing and / or pressing and / or plugging together and / or form fit and / or magnetic interaction and / or vacuum or Saugdruckbeaufschlagung can be realized.

In the case of an exemplary screw connection, it would be conceivable, for example, for one end of the electronic pen to have a thread profile which is complementary to a hollow profile of the at least one holding means, so that the end of the electronic pen can be screwed into the hollow profile of the at least one holding means.

Alternatively or as a support, the use of a residue-free, detachable adhesive connection would also be conceivable for a/the connection of the holding means to the electronic pen.

Depending on the design, an exemplary calibration device can have one or at least two holding means, it being possible, for example, for one holding means to be arranged at one end of the housing of the calibration device.

However, the at least two holding means can also be arranged at other points of the housing of the calibration device.

The use of at least two holding means can enable a more stable/low-vibration fixation of an electronic pen to be/is received in the housing of the calibration device.

The at least one holding means can be designed in such a way that it can enable flat and/or punctiform/discrete holding contact with the electronic pen.

For example, for low-vibration fixation of an electronic pen to be held/received, a flat-acting holding means, for example a holding means in the form of a foam insert with a suitable cut-out, can be used, in which case the holding means designed as a foam insert can be oversized relative to the cavity of the calibration device housing into which it can be inserted .

Likewise, the use of at least two holding means can make it easier to fix the electronic pen to be held / received in such a way that the longitudinal axis of the held electronic pen can be oriented parallel to the longitudinal axis of the housing, or that the longitudinal axis of the held electronic pen is aligned with the longitudinal axis of the Housing can collapse.

The use of a surface-acting holding means or at least two discrete holding means thus also contributes to reducing noise in the measurement data/measurement signals of the inertial measurement sensors of the electronic pen.

The at least one holding means can also be integrated into a housing cover of the housing of the calibration device.

For example, the at least one holding means can be integrated into a housing cover at one end of the housing.

If at least two holding means are used, one holding means can be integrated in each case in a housing cover at both ends of the housing, for example.

Said exemplary housing cover can be removable. A detachable connection of the housing cover / the housing cover with the housing can, inter alia, via terminals and / or Screwing and / or pressing and / or form fit and / or magnetic interaction are produced.

As a result, a more compact design of the calibration device can be achieved and, among other things, the insertion of an electronic pen into the housing of the calibration device can be made easier.

In the case of the calibration device or the housing of the calibration device, it can also be advantageous if this is permeable to electromagnetic waves, e.g. to enable data and command communication with an external digital processing unit.

This can enable the transmission of measurement data from the inertial measurement sensors of the electronic pen to an external digital processing unit for processing and evaluating the measurement data.

The electronic pen can have a communication module, for example, which can enable encrypted wireless data transmission according to the Bluetooth Low Energy (BLE) standard.

As an alternative or in addition, cable-bound data and command communication between the electronic pen and an external digital processing unit is conceivable, even if the electronic pen is located in the calibration device.

1. 1. Ein Einlegen des elektronischen Schreibstiftes in eine wie hierin beispielhaft beschriebene Kalibriervorrichtung, wobei beim bzw. vor dem Einlegen des elektronischen Schreibstiftes, der elektronische Schreibstift bzw. die inertiale Messsensorik aktiviert / eingeschaltet werden kann.
2. 2. Ein Drehen der Kalibriervorrichtung mit eingelegtem elektronischen Schreibstift um wenigstens eine Achse, z.B. eine/die Längsachse, der Kalibriervorrichtung, wobei während der Drehung der Kalibriervorrichtung mit eingelegtem elektronischen Schreibstift Messdaten der inertialen Messsensorik des elektronischen Schreibstiftes aufgenommen werden können, und wobei die aufgenommenen Messdaten Beschleunigungsmesswerte von wenigstens einem Beschleunigungssensor der inertialen Messsensorik und/oder Drehratenmesswerte von wenigstens einem Drehratensensor umfassen können.
3. 3. Eine Bestimmung wenigstens eines Nullpunktfehlers in wenigstens einer Achse des / eines Beschleunigungssensors der inertialen Messsensorik durch Auswertung der aufgenommenen Messdaten.
4. 4. Eine Kalibrierung der inertialen Messsensorik des elektronischen Schreibstiftes auf Grundlage des wenigstens einen bestimmten Nullpunktfehlers.

A method for calibrating an inertial measuring sensor system of an electronic pen includes the following steps:

1. 1. Insertion of the electronic pen in a calibration device as described here by way of example, it being possible for the electronic pen or the inertial measuring sensor system to be activated/switched on during or before the insertion of the electronic pen.
2. 2. Rotating the calibration device with the electronic pen inserted about at least one axis, e.g. one/the longitudinal axis of the calibration device, wherein measurement data of the inertial measurement sensor system of the electronic pen can be recorded during the rotation of the calibration device with the electronic pen inserted, and the recorded measurement data Acceleration measurement values from at least one acceleration sensor of the inertial measurement sensor system and/or yaw rate measurement values from at least one yaw rate sensor.
3. 3. A determination of at least one zero point error in at least one axis of the/an acceleration sensor of the inertial measurement sensor system by evaluating the recorded measurement data.
4. 4. A calibration of the inertial measurement sensors of the electronic pen based on the at least one specific zero point error.

The calibration device can preferably be rotated or tilted about three mutually orthogonal axes with the electronic pen inserted.

For the sake of completeness, it should be mentioned that the electronic pen may have to be switched on or activated before it is placed in the calibration device or before the calibration device begins to rotate, so that the inertial measurement sensors can be activated or put on standby to record measurement data to be able to record and/or to be able to communicate with an external digital processing unit if necessary.

The exemplary method step of recording measurement data from the inertial measurement sensor system while the calibration device is rotating with the electronic pen inserted can in particular include the case/possibility that the calibration device moves during the measurement data recording, i.e. rotates during the measurement data recording, i.e. also the case/the Possibility of measuring data being recorded when the calibration device is not moving and is in a rest position or holding position, for example, for a predefinable period of time during a rotation process from one rotation angle position to another rotation angle position.

The notion of rotation or the rotation process of the calibration device in the exemplary method described above therefore includes both continuous and stepwise rotations, wherein said stepwise rotations can have well-defined rest positions with well-defined angular positions of rotation at/in/at which the calibration device does not move.

Said exemplary longitudinal axis of the calibration device can therefore be understood as a rotation axis for a/rotation of the calibration device with an inserted electronic pen. However, a process of rotating the calibration device can also include rotations or tilting about other axes of the calibration device, for example rotations or tilting about edge or lateral axes of the calibration device.

The exemplary calibration of the inertial measurement sensor system of the electronic pen on the basis of the at least one specific zero point error can be understood, among other things, to mean that the measurement data of the inertial measurement sensor system or the sensor axes are corrected, for example by the position of the zero points of the measurement data or the sensor axes being corrected by the amount of the determined/determined zero point error is corrected, e.g. by appropriate addition or subtraction of the determined/determined zero point error value. In addition, the term calibration of the inertial measurement sensors of the electronic pen can also be understood to mean that the measurement data of the inertial measurement sensors can be scaled or normalized.

The turning of the calibration device with the electronic pen inserted about a/the longitudinal axis of the calibration device can be carried out continuously and/or in steps.

A step-by-step rotation of the calibration device with the electronic pen inserted can include, for example, a sequence or succession of rotations or rotation angle positions.

The rotation angle steps between successive rotations/rotational angle positions can be freely selected, i.e. they can be the same or different, for example.

The sense of rotation for a continuous rotation and/or for each rotation angle step of a step-by-step rotation can be freely selected.

A turning operation may also include a combination of continuous and incremental turns of the calibration fixture.

A turning process can in particular also include a series or sequence of turnings or tilting about different axes or different edges of a calibration device. The process of rotating the calibration device can therefore include rotations or tilting around a large number of different axes of the calibration device. Preferably, the turning process can include a predetermined sequence of axes about which rotations or tilting take place.

A rotation process preferably covers a sufficient number of rotation angle positions to be able to collect measuring points of the inertial measuring sensor system of the electronic pen located in the calibration device over at least one full revolution or over at least a quarter or over at least half a revolution.

For example, it would be conceivable to collect measuring points of the inertial measuring sensor system at at least six different angular positions distributed over one revolution.

The distribution of rotary angle positions over a full revolution can be uniform or non-uniform, with non-uniform distribution for example adjacent rotary angle positions being able to differ by more than 10°, for example.

As mentioned, the process of rotating the calibration device can include rotations or tilting about a number of different axes, so that, for example, the electronic pen held by the calibration device can be aligned in different discrete spatial directions.

For example, the calibration device can be cuboid and enable, for example, alignment in at least six different discrete directions, two of which lie in pairs on axes that are orthogonal to at least one other direction. In this case, for example, the side surfaces of the calibration device can define different orientations of the calibration device. In the case of an exemplary cuboid calibration device, the six different side faces can thus define, for example, six different orientations of the calibration device.

1. 1. Ein Ruhen / Halten der Kalibriervorrichtung in einer Ruheposition mit Kalibration der Nullpunkte der Achsen der Drehratensensoren der inertialen Messsensorik des elektronischen Schreibstiftes und gleichzeitige Aufnahme von Messdaten der Beschleunigungssensoren. Hierbei kann beispielsweise die Kalibriervorrichtung auf einer Fläche der Kalibriervorrichtung ruhen.
2. 2. Drehen der Kalibriervorrichtung um eine definierte Achse um 180° mit Integration der Drehratensensordaten zur Ermittlung des Winkels der Drehung. Das Ergebnis der Integration, korrigiert um den in Schritt 1 ermittelten Nullpunkt, kann dabei zur Skalierung der Achse des Drehratensensors, um den die Drehung erfolgte, verwendet werden.
3. 3. Ein Ruhen / Halten der Kalibriervorrichtung in der neuen Ruheposition, d.h. z.B. Ruhen auf der um 180° gedrehten gegenüberliegenden Fläche der Kalibriervorrichtung. Dabei können in der neuen Ruheposition wiederum Messdaten der Beschleunigungssensoren aufgenommen werden.
4. 4. Drehung / Kippung der Kalibriervorrichtung auf eine weitere Fläche der beispielhaften sechs Flächen der Kalibriervorrichtung.
5. 5. Ein Ruhen / Halten der Kalibriervorrichtung in der neuen Ruheposition und Aufnahme von Messdaten der Beschleunigungssensoren.
6. 6. Wiederholung der Schritte 2 bis 5, bis Messdaten in allen Ruhepositionen für alle (sechs) Seiten der Kalibriervorrichtung aufgenommen werden konnten.
7. 7. Auswertung der Messdaten. Dabei kann die Summe der Werte der Messdaten in/entlang jeweils einer Achse/Sensorachse für alle, z.B. sechs, während der Ruhepositionen eingenommenen verschiedenen Ausrichtungen der Kalibriervorrichtung , zur Ermittlung der Nullpunkte der jeweiligen Achse / Sensorachse dienen.

An exemplary rotating curtain or calibration process of a calibration device on a support surface with an electronic pen can then include one, some or all of the following steps.

1. 1. Resting/holding the calibration device in a rest position with calibration of the zero points of the axes of the yaw rate sensors of the inertial measurement sensor system of the electronic pen and simultaneous recording of measurement data from the acceleration sensors. Here, for example, the calibration device can rest on a surface of the calibration device.
2. 2. Rotating the calibration device around a defined axis by 180° with integration of the yaw rate sensor data to determine the angle of rotation. The result of the integration, corrected by the zero point determined in step 1, can be used to scale the axis of the rotation rate sensor about which the rotation took place.
3. 3. Resting/holding the calibration device in the new rest position, ie resting on the opposite surface of the calibration device rotated by 180°. Measurement data from the acceleration sensors can again be recorded in the new resting position.
4. 4. Rotation/tilting of the calibration device onto another surface of the exemplary six surfaces of the calibration device.
5. 5. Resting/holding the calibration device in the new rest position and recording measurement data from the acceleration sensors.
6. 6. Repeat steps 2 to 5 until measurement data could be taken in all rest positions for all (six) sides of the calibration device.
7. 7. Evaluation of the measurement data. The sum of the values of the measurement data in/along a respective axis/sensor axis for all, for example six, different orientations of the calibration device assumed during the rest positions can be used to determine the zero points of the respective axis/sensor axis.

The scaling of the acceleration sensor axes can then be obtained, for example, after correcting all values of the measurement data around the respective zero point and dividing the respective measurement values obtained in the axis parallel to the gravitational acceleration by the number of measurements.

The recording of measurement data from the inertial measurement sensor system of the electronic pen located in the calibration device, in particular the recording of measured acceleration values from at least one acceleration sensor of the inertial measurement sensor system, can also take place continuously and/or step by step.

It was surprisingly found that if the measurement data of the inertial measurement sensor system of the electronic pen collected during the continuous and/or stepwise rotation of the calibration device with the electronic pen inserted, in particular the measured acceleration values of at least one acceleration sensor of the inertial measurement sensor system, as a function of the rotational angle position ( en) of the calibration device, there is a low-noise and well-defined relationship between the measured acceleration values of at least one acceleration sensor of the inertial measuring sensor system as a function of the angular position of the calibration device, which can be well described with a model function, in particular with a trigonometric model function, and from which the zero point error in the axes/measuring axes/sensor axes of the at least one acceleration sensor of the inertial measurement sensor system can be determined, which can serve as a basis for calibrating the acceleration sensor or the inertial measurement sensor system.

In particular, it was found that the relationship between the measured acceleration values of at least one acceleration sensor of the inertial measurement sensor system of the electronic pen located in the calibration device as a function of the angular position of the calibration device can be described almost as an ideal sinusoidal curve.

A suitable model function, in particular a suitable trigonometric function for modeling the measured acceleration values as a function of the rotational angle positions of the calibration device, or as a function of the continuously and/or stepwise changing rotational angle positions of the calibration device, can therefore, for example, include a sine function or a sine function with or without displacement term, e.g. with a vertical displacement term.

A determination of at least one zero point error in at least one axis of the acceleration sensor of the inertial measuring sensor system can then be carried out by evaluating the recorded measurement data by modeling the recorded acceleration measurement values as a function of the rotational angle positions assumed during the rotation of the calibration device by a / said suitable trigonometric function, e.g. by a sine function , take place, wherein the at least one zero point error in at least one axis of the acceleration sensor can be determined on the basis of a specific shift of the modeled trigonometric function to the zero line.

For example, the measured acceleration values recorded can then be modeled as a function of the rotary angle positions of the calibration device using a modeling function that includes a sine function and a vertical displacement term (displacement term with respect to an/the ordinate axis).

An optimization algorithm can then be used to find those parameter values of the parameters of the modeling function that best describe the measured curve of the recorded acceleration measurement values as a function of the rotational angle positions of the calibration device or minimize a cost function.

The sum of the squared errors of the distances between the model function curve and the measurement points can be used as an example of a cost function to be minimized.

For example, that model function curve can then be determined which minimizes the sum of the squared errors of the distances between the model function curve and the measurement points.

For example, the amplitude and/or the phase/the phase angle and/or the frequency of the/a sine function and/or a vertical displacement term can be used as parameters to be optimized for this purpose.

In order to determine the optimal parameter values in this multidimensional model parameter space, which define the model function that best describes the measurement data, a parameter value search can be carried out over a grid of the model parameter space, i.e. a brute force method, or other optimization algorithms, such as a downhill Simplex method can be used.

The determined vertical displacement / the value of the vertical displacement of the model function / model function curve that best describes the measurement data / the acceleration measurement values in relation to the zero line can then serve as a measure for the zero point error, or as a zero point error value, in the corresponding acceleration sensor axis.

In particular, said determined vertical displacement / said value of the vertical displacement of the measurement data, or the vertical displacement of the model function that best describes the recorded acceleration measurement values in relation to the zero line, can then be used as a measure of the zero point error in acceleration sensor axes that are orthogonal or approximately orthogonal to the axis of rotation or axis of rotation of the calibration device are taken.

However, it is also conceivable that the optimal parameter values of the model function and/or the vertical shift of the model function that best fits the zero line in order to determine a zero point error of an acceleration sensor of the inertial measurement sensor system, are also determined or estimated differently, i.e. without using optimization algorithms can, for example by using an appropriately trained neural network.

Before the previously described exemplary modeling of the recorded acceleration measurement values using a model function such as the exemplary trigonometric model function described above or the exemplary sine function with displacement term, the angular orientation of the coordinate system of the inertial measuring sensors of the electronic pen can be determined from the measured data of the inertial measuring sensors of the electronic pen / the angular orientation of the axes of the orthogonal three-dimensional inertial measurement system / the angular orientation of the sensor axes of the inertial measurement sensors in relation to the axis of rotation can be determined.

Said angular orientation of the sensor axes of the inertial measurement sensor system in relation to the axis of rotation can be determined, for example, as follows from measurement data of the inertial measurement sensor system. In this case, for example, the orthogonal three-dimensional inertial measurement system is spanned by the exemplary axes/sensor axes X, Y and Z that are orthogonal to one another.

For example, if axi is the measured acceleration value in the X-axis direction in a first orientation of the calibration device's rotational axis perpendicular to the gravitational vector, and ax2 is the measured acceleration value in the X-axis direction in a perpendicular orientation parallel to the gravitational vector of the calibrating device, the Said angular errors/ the angular orientation of the sensor axes of the inertial measuring sensors in relation to the gravity vector determined from the formula: $$\text{angular error}=a\mathrm{right}ctan\left(\frac{ax1}{ax2}\right)$$

where arctan is the arctangent function. If ax2 is less than zero, the angular orientation results from the additional addition of π to the value obtained from the formula.

Thus, the amplitude of the trigonometric function obtained by minimizing the least squares may be proportional to the location/distance/offset of the accelerometer axis with respect to the axis of rotation.

The proportionality factor can be calculated directly by applying the arctangent function using the measured value when the axis of the acceleration sensor is almost vertical. Due to a possible angular error between the sensor axis and the axis of rotation of the calibration device, the sensor axis will not be exactly vertical even after the calibration device has been rotated by exactly 90°. However, this possible error only leads to deviations of the measured values from their ideal target value in the amount of the cosine function. For small angles, this has only very small deviations from the value 1, which it would achieve if the sensor axis were aligned exactly vertically. This is why, despite a possible angle error, a very precise measurement of the angle between the sensor axis and the axis of rotation is possible, since the denominator of the argument is the Arctangent function allows very precise normalization.

Before turning the calibration device with the electronic pen inserted, it is also optionally conceivable that the calibration device is at rest, i.e. not moved, in order to be able to determine a zero point of a yaw rate sensor/zero points of yaw rate sensors of the inertial measuring sensor system and to be able to calibrate the yaw rate sensors accordingly.

Such a zero point error correction / zero point error calibration of the yaw rate sensors of the inertial measuring sensor system makes it possible, for example, to separate possible errors due to a possible angle deviation of the sensor axis and a zero point error of the sensor in the same axis of the recorded acceleration measurement values and thus also the accuracy of the modeling of the recorded acceleration measurement values by a model function to further improve.

In order to further improve the accuracy with which the recorded acceleration measurement values can be modeled, it is also conceivable that the zero points of the yaw rate sensors be determined several times during a calibration process with the calibration device, for example in each/one rest position of the calibration device with a stepwise rotation of the calibration device .

In other words, one can proceed iteratively in order to be able to gradually determine and correct zero point errors of the yaw rate sensors and zero point errors of the acceleration sensors by repeated measurements and averaging over the repeated measurements.

A rest position can be understood here to mean, among other things, a position or position of the calibration device in which the rotation rate sensors of the inertial measurement sensor system do not experience any rotation rate changes and/or the acceleration sensors of the inertial measurement sensor system experience no or only a negligibly small gravitational acceleration, or in which the Target measurement signals of the yaw rate sensors and/or the target measurement signals of the acceleration sensors of the inertial measurement sensor system are below a definable measurement signal threshold.

Rotating the calibration device with the electronic pen inserted about at least one axis / about a / the longitudinal axis / about a / the axis of rotation of the calibration device can incidentally on be carried out on a level surface / level base / smooth base, e.g. on a desk.

This makes it particularly easy to find a position of the calibration device that is perpendicular to the axis of gravitational acceleration.

This can also lead to a reduction in the scatter or a reduction in the noise in the measurement data of the inertial measurement sensor system, which in turn can also increase the accuracy with which the measurement sensor system of the electronic pen can be calibrated.

As already mentioned, the turning of the calibration device with an inserted electronic pen around a/the longitudinal axis of the calibration device can take place continuously and/or in steps.

For example, a step-by-step rotation of the calibration device with the electronic pen inserted around at least one axis/around one/the longitudinal axis of the calibration device can comprise a sequence of rotation processes in which the calibration device is in a rest position between two consecutive rotation processes, in which the calibration device is not moved for a predetermined period of time and measurement data from the inertial measurement sensors are recorded when the calibration device is in a rest position. For example, it is conceivable that measurement data from the inertial measurement sensor system is only, i.e. exclusively, recorded when the calibration device is in a rest position.

For example, said predeterminable period of time, in which the calibration device is in a rest position, can be of the order of seconds, for example 5 to 10 seconds. With an exemplary measuring frequency of 100 Hz, between 500 and 1000 measured values per rest position can be collected and averaged.

However, other longer or shorter periods of time are also conceivable depending on the measurement frequency used.

Said exemplary stepwise rotation of the calibration device with the electronic pen inserted around at least one axis of the calibration device/around at least one axis of the housing of the calibration device can, for example, include at least one rotation process with a rotation of the calibration device by 180°.

As already mentioned, enabling a precise rotation of the calibration device by 180° makes it possible to minimize possible sources of error when determining the zero point of the axes of the acceleration sensors of the electronic pen, since possible angle errors in the alignment of the electronic pen to axes, e.g. main axes, of the calibration device cancel each other out if the measurement data of the acceleration sensors are recorded and evaluated at two different rotational positions of the calibration device by 180° to determine the zero point / zero point error.

As also already mentioned, the calibration device can comprise a housing with six side surfaces. The housing of the calibration device/the calibration device can therefore be cubic or cuboid.

An example of turning the calibration device with the electronic pen inserted can include, in particular, a sequence of turning processes in which each of the side surfaces of the calibration device / each of the side surfaces of the housing of the calibration device assumes an orientation at least once in which the respective side surface acts as a bearing surface for the calibration device on a flat surface surface can serve.

As also already mentioned, a rest position of the calibration device can be defined or detected in that the inertial measurement sensor system does not measure any changes in the measurement signal or no measurement signals, such as changes in the rate of rotation and/or acceleration signals, or the measurement signals are below a definable measurement signal threshold.

Such optional rest positions of the calibration device in different angular positions during a gradual rotation of the calibration device with an inserted electronic pen offer numerous advantages.

For example, in each resting position, several measured acceleration values for the respective angular position of the calibration device can be measured, stored and averaged, so that the accuracy with which acceleration values can be determined for each angular position of the calibration device increases.

Likewise, a number of yaw rate sensor measurements can be made and stored in each rest position, which, among other things, can also be averaged and can enable a more precise determination of the zero point error of the yaw rate sensors.

In addition, the measurement data of the inertial measurement sensor system recorded when the calibration device is in a resting position are less subject to interference, such as shocks or vibrations, and are therefore generally more accurate per se than measurement data recorded while the calibration device is moving.

A more accurate and low-noise measurement data set can thus be generated, which can improve the accuracy of the modeling of the recorded acceleration measurement values described above by way of example as a function of the rotational angle positions assumed during the rotation of the calibration device, which consequently leads to a more precise determination of zero point errors of the acceleration sensors and thus to an improved Calibration of the inertial measurement sensors.

A continuous or step-by-step rotation process preferably covers a sufficient number of rotation angle positions to be able to collect measuring points of the inertial measuring sensor system of the electronic pen located in the calibration device over at least one full revolution or over at least a quarter of a revolution or over at least half a revolution.

For example, it is conceivable that a step-by-step turning process includes an integral number of rotational angle positions or an integral number of revolutions, e.g. at least three revolutions, with each turning process step being carried out uniformly.

In particular, it is conceivable, for example when using a cuboid calibration device, for the step-by-step turning process to include rotating or tilting the calibration device, in which each side surface of the calibration device defines a rotational angle position in which measurement data can be recorded.

As mentioned, the calibration device can be rotated with the electronic pen inserted about at least one axis, e.g. the longitudinal axis/rotational axis or a lateral axis/edge axis, of the calibration device/the calibration device housing on a flat surface.

This can make it easier to set or reach said rest positions of the calibration device, and increase the rest of the movement at a rest position of the calibration device that has been reached, which in turn can also lead to a reduction in the measurement data scatter or measurement data noise.

As mentioned, the cross section of the housing of the calibration device can be cylindrical or polygonal, for example. In particular, the cross-section of the housing/the cross-sectional profile of the calibration device can be rotationally symmetrical.

For example, the housing of the calibration device can be tubular or cylindrical.

A rotationally symmetrical, e.g. a cylindrical or tubular cross-sectional profile, in particular a circular-cylindrical cross-sectional profile of the housing of the calibration device, can facilitate, among other things, a more uniform rotation of the calibration device, which also reduces noise in the measurement data of the inertial measurement sensor system, in particular in acceleration measurement values of the acceleration sensor of the inertial measurement sensor system, can decrease.

A polygonal cross-section or a polygonal cross-sectional profile of the housing of the calibration device can make it easier, among other things, to set and run through a well-defined sequence of rotational positions/rotation angles/rotation angle positions of the calibration device when the calibration device is rotated with the electronic pen attached.

In addition, with a polygonal cross-sectional profile of the housing of the calibration device, e.g. with a cuboid design of the calibration device housing, well-defined rest positions of the calibration device can be assumed when the calibration device is rotated step by step, since, for example, for each rotational angle position of a step by step rotation, the calibration device rests on a side surface of the Housing of the calibration device can rest.

A polygonal cross-sectional profile of the housing of the calibration device, as is the case, for example, with a cuboid calibration device, thus enables a more stable rest position of the calibration device during stepwise rotation.

This in turn can further reduce the noise in the measurement data of the inertial measurement sensor system, which is assumed during the rest positions when the calibration device is rotated step by step, and thus enable a more precise calibration of the inertial measurement sensor system of the electronic pen.

1. 1. Einlegen des elektronischen Schreibstiftes in die Kalibriervorrichtung.
2. 2. Ruhen der Kalibriervorrichtung in einer Halte-/Ruheposition und Messung von Drehraten und Beschleunigungen in allen Achsen der inertialen Messsensorik und Speichern der Messdaten;
3. 3. Bestimmung wenigstens eines Nullpunktfehlers in wenigstens einer Achse des Drehratensensors der inertialen Messsensorik durch Auswertung der aufgenommenen Messdaten.
4. 4. Rotation / Drehung / Kippung der Kalibriervorrichtung um 180° auf eine gegenüberliegende Seite, dabei Messung und Integration der Drehraten. Ermittlung des Kalibrierfaktors der Skalierung um die Rotationsachse nach Korrektur um den vorher ermittelten Nullpunktfehler.
5. 5. Ruhen der Kalibriervorrichtung in der neuen Position, dabei Messung von Beschleunigungen in allen Achsen der inertialen Messsensorik und Speichern der Messdaten.
6. 6. Rotation / Drehung / Kippung der Kalibriervorrichtung auf eine weitere Seitenfläche und Wiederholung der vorherigen Schritte 4 bis 6, bis Messdaten auf allen sechs Seiten/Seitenflächen gesammelt wurden.
7. 7. Kalibrierung / Skalierung der Beschleunigungssensoren und Drehratensensoren der inertialen Messsensorik in allen Achsen der inertialen Messsensorik. Dabei können die integrierten Drehraten über die 180°-Drehungen mit Pi normiert werden und einen Faktor bilden, mit dem zukünftige Messungen der Drehrate um ihren Skalierungsfehler korrigiert werden können. Dann können z.B. die Mittelwerte der in den Ruhephasen/an den Ruhepositionen gesammelten Beschleunigungswerte jeweils paarweise ausgewertet gemäß folgender beispielhafter Formeln: $$\text{Nullpunktfehler in X}=\left(\frac{X1+\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">X</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="X"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="X"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">X</figure-callout>}4+X5+\mathrm{<figure-callout\; id="6"\; label="X"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}6}{6}\right)-\text{Sollwert}\left(\text{X0}\right)$$
   
   $$\text{Nullpunktfehler in Y}=\left(\frac{Y1+\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Y</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="Y"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="Y"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Y</figure-callout>}4+Y5+\mathrm{<figure-callout\; id="6"\; label="Y"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}6}{6}\right)-\text{Sollwert}\left(\text{Y0}\right)$$
   
   $$\text{Nullpunktfehler in Z}=\left(\frac{Z1+\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Z</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Z</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="Z"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Z</figure-callout>}4+Z5+\mathrm{<figure-callout\; id="6"\; label="Z"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Z</figure-callout>}6}{6}\right)-\text{Sollwert}\left(\text{Z0}\right)$$
   
   $$\text{Winkelfehler der X}-\text{Asche in der X}-\text{Z}-\text{Ebene}=\text{Arctan}\left(\frac{X1+X2-2-Sollwert\left(X0\right)}{\left|X5-\mathrm{<figure-callout\; id="6"\; label="X"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}6\right|}\right)$$
   
   $$\text{Winkelfehler der X}-\text{Asche in der X}-\text{Y}-\text{Ebene}=\text{Arctan}\left(\frac{\mathrm{<figure-callout\; id="3"\; label="X"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="X"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">X</figure-callout>}4-2-Sollwert\left(X0\right)}{\left|X5-\mathrm{<figure-callout\; id="6"\; label="X"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}6\right|}\right)$$
   
   $$\text{Winkelfehler der Y}-\text{Asche in der Y}-\text{Z}-\text{Ebene}=\text{Arctan}\left(\frac{Y1+\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Y</figure-callout>}2-2-Sollwert\left(Y0\right)}{\left|\mathrm{<figure-callout\; id="3"\; label="Y"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}3-\mathrm{<figure-callout\; id="4"\; label="Y"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Y</figure-callout>}4\right|}\right)$$
   
   $$\text{Winkelfehler der Y}-\text{Asche in der X}-\text{Y}-\text{Ebene}=\text{Arctan}\left(\frac{Y5+\mathrm{<figure-callout\; id="6"\; label="Y"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}6-2-Sollwert\left(Z0\right)}{\left|\mathrm{<figure-callout\; id="3"\; label="Y"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}3-\mathrm{<figure-callout\; id="4"\; label="Y"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Y</figure-callout>}4\right|}\right)$$
   
   $$\text{Winkelfehler der Z}-\text{Asche in der X}-\text{Z}-\text{Ebene}=\text{Arctan}\left(\frac{Z5+\mathrm{<figure-callout\; id="6"\; label="Z"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Z</figure-callout>}6-2-Sollwert\left(Z0\right)}{\left|Z1-\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Z</figure-callout>}2\right|}\right)$$
   
   $$\text{Winkelfehler der Z}-\text{Asche in der Y}-\text{Z}-\text{Ebene}=\text{Arctan}\left(\frac{\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Z</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="Z"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Z</figure-callout>}4-2-Sollwert\left(Z0\right)}{\left|Z1-\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Z</figure-callout>}2\right|}\right)$$
   
   $$\text{Skalierungsfehler der X}-\text{Achse}=\frac{\left|X5-\mathrm{<figure-callout\; id="6"\; label="X"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}6\right|}{Sollwert\left(1g\right)}$$
   
   $$\text{Skalierungsfehler der Y}-\text{Achse}=\frac{\left|\mathrm{<figure-callout\; id="3"\; label="Y"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}3-\mathrm{<figure-callout\; id="4"\; label="Y"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Y</figure-callout>}4\right|}{Sollwert\left(1g\right)}$$
   
   $$\text{Skalierungsfehler der Z}-\text{Achse}=\frac{\left|Z1-\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Z</figure-callout>}2\right|}{Sollwert\left(1g\right)}$$
   

In this case, for example, an integer multiple can also be selected for the number of side surfaces of the housing of the calibration device, which, among other things, simplifies the evaluation of the measurement data of the inertial measurement sensors, which can be recorded at the angle of rotation/rotational angle positions of the calibration device defined by the different side surfaces, since a well-defined sampling of measurement data can be obtained. In an exemplary cubic or cuboid design of the housing of the calibration device, the calibration device/the housing of the calibration device has six side surfaces, for example, and an exemplary method for calibrating an inertial measuring sensor system of an electronic pen can have one, some or all of the following steps.

1. 1. Insertion of the electronic pen into the calibration device.
2. 2. Resting the calibration device in a holding/resting position and measurement of yaw rates and accelerations in all axes of the inertial measurement sensor system and storage of the measurement data;
3. 3. Determination of at least one zero point error in at least one axis of the yaw rate sensor of the inertial measurement sensor system by evaluating the recorded measurement data.
4. 4. Rotation / turning / tilting of the calibration device by 180° to an opposite side, measuring and integrating the yaw rates. Determination of the calibration factor of the scaling around the axis of rotation after correction by the previously determined zero point error.
5. 5. Resting of the calibration device in the new position, measurement of accelerations in all axes of the inertial measurement sensors and storage of the measurement data.
6. 6. Rotate/rotate/tilt the calibration fixture onto another face and repeat previous steps 4 through 6 until measurement data has been collected on all six faces/faces.
7. 7. Calibration / scaling of the acceleration sensors and yaw rate sensors of the inertial measurement sensors in all axes of the inertial measurement sensors. The integrated yaw rates over the 180° rotations can be normalized with Pi and form a factor with which future measurements of the yaw rate can be corrected for their scaling error. Then, for example, the mean values of the acceleration values collected in the rest phases/at the rest positions can be evaluated in pairs according to the following exemplary formulas: $$\text{Zero error in X}=\left(\frac{X1+\mathrm{<figure-callout\; id="2"\; label="X"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">X</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="X"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="X"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">X</figure-callout>}4+X5+\mathrm{<figure-callout\; id="6"\; label="X"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}6}{6}\right)-\text{setpoint}\left(\text{X0}\right)$$
   
   $$\text{Zero error in Y}=\left(\frac{Y1+\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Y</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="Y"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="Y"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Y</figure-callout>}4+Y5+\mathrm{<figure-callout\; id="6"\; label="Y"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}6}{6}\right)-\text{setpoint}\left(\text{Y0}\right)$$
   
   $$\text{Zero error in Z}=\left(\frac{Z1+\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Z</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Z</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="Z"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Z</figure-callout>}4+Z5+\mathrm{<figure-callout\; id="6"\; label="Z"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Z</figure-callout>}6}{6}\right)-\text{setpoint}\left(\text{Z0}\right)$$
   
   $$\text{Angular error of the X}-\text{Ashes in the X}-\text{Z}-\text{level}=\text{arctan}\left(\frac{X1+X2-2-SOllwe\mathrm{right}t\left(X0\right)}{\left|X5-\mathrm{<figure-callout\; id="6"\; label="X"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}6\right|}\right)$$
   
   $$\text{Angular error of the X}-\text{Ashes in the X}-\text{Y}-\text{level}=\text{arctan}\left(\frac{\mathrm{<figure-callout\; id="3"\; label="X"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="X"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">X</figure-callout>}4-2-SOllwe\mathrm{right}t\left(X0\right)}{\left|X5-\mathrm{<figure-callout\; id="6"\; label="X"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}6\right|}\right)$$
   
   $$\text{angular error of the Y}-\text{Ash in the Y}-\text{Z}-\text{level}=\text{arctan}\left(\frac{Y1+\mathrm{<figure-callout\; id="2"\; label="Y"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Y</figure-callout>}2-2-SOllwe\mathrm{right}t\left(Y0\right)}{\left|\mathrm{<figure-callout\; id="3"\; label="Y"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}3-\mathrm{<figure-callout\; id="4"\; label="Y"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Y</figure-callout>}4\right|}\right)$$
   
   $$\text{angular error of the Y}-\text{Ashes in the X}-\text{Y}-\text{level}=\text{arctan}\left(\frac{Y5+\mathrm{<figure-callout\; id="6"\; label="Y"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}6-2-SOllwe\mathrm{right}t\left(Z0\right)}{\left|\mathrm{<figure-callout\; id="3"\; label="Y"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}3-\mathrm{<figure-callout\; id="4"\; label="Y"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Y</figure-callout>}4\right|}\right)$$
   
   $$\text{Angular error of the Z}-\text{Ashes in the X}-\text{Z}-\text{level}=\text{arctan}\left(\frac{Z5+\mathrm{<figure-callout\; id="6"\; label="Z"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Z</figure-callout>}6-2-SOllwe\mathrm{right}t\left(Z0\right)}{\left|Z1-\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Z</figure-callout>}2\right|}\right)$$
   
   $$\text{Angular error of the Z}-\text{Ash in the Y}-\text{Z}-\text{level}=\text{arctan}\left(\frac{\mathrm{<figure-callout\; id="3"\; label="Z"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Z</figure-callout>}3+\mathrm{<figure-callout\; id="4"\; label="Z"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Z</figure-callout>}4-2-SOllwe\mathrm{right}t\left(Z0\right)}{\left|Z1-\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Z</figure-callout>}2\right|}\right)$$
   
   $$\text{X scaling error}-\text{axis}=\frac{\left|X5-\mathrm{<figure-callout\; id="6"\; label="X"\; filenames="DE102022111845B3\_0015.png"\; state="\{\{state\}\}">X</figure-callout>}6\right|}{SOllwe\mathrm{right}t\left(1G\right)}$$
   
   $$\text{Y scaling error}-\text{axis}=\frac{\left|\mathrm{<figure-callout\; id="3"\; label="Y"\; filenames="DE102022111845B3\_0014.png,DE102022111845B3\_0015.png"\; state="\{\{state\}\}">Y</figure-callout>}3-\mathrm{<figure-callout\; id="4"\; label="Y"\; filenames="DE102022111845B3\_0014.png"\; state="\{\{state\}\}">Y</figure-callout>}4\right|}{SOllwe\mathrm{right}t\left(1G\right)}$$
   
   $$\text{Z scaling error}-\text{axis}=\frac{\left|Z1-\mathrm{<figure-callout\; id="2"\; label="Z"\; filenames="DE102022111845B3\_0018.png"\; state="\{\{state\}\}">Z</figure-callout>}2\right|}{SOllwe\mathrm{right}t\left(1G\right)}$$
   

Here, for example, X1, Y1, Z1 are the mean values of the measured accelerations when the calibration device is oriented on its base and the Z axis of the calibration device is parallel to the gravitational acceleration, while the other two axes are each oriented perpendicular to the gravitational acceleration. X2, Y2, Z2 are the mean values of the measured acceleration after rotating the calibration device by 180° so that it comes to rest with its base facing upwards. Therefore, the Z-axis of the calibration device is again parallel to the gravitational acceleration, while the other two axes are again each oriented perpendicular to the gravitational acceleration.

X3, Y3, Z3 are the mean values of the measured acceleration after turning the calibration device on its long side, the Y axis of the calibration device now being oriented parallel to the acceleration due to gravity and the other two axes being oriented perpendicular to the acceleration due to gravity. X4, Y4 and Z4 are the mean values of the measured acceleration after rotating the calibration device by 180° to the side opposite the long side, with the Y-axis of the calibration device now again being oriented parallel to the gravitational acceleration and the other two axes each being oriented perpendicular to the gravitational acceleration be.

X5, Y5, Z5 are the mean values of the measured acceleration after turning the calibration device on its lateral side, the X axis of the calibration device now being oriented parallel to the acceleration due to gravity and the other two axes being oriented perpendicular to the acceleration due to gravity. X6, Y6 and Z6 are the mean values of the measured acceleration after rotating the calibration device by 180° to the side opposite the lateral side, with the X-axis of the calibration device now again being oriented parallel to the gravitational acceleration and the other two axes each being oriented perpendicular to the gravitational acceleration be.

Setpoint(X0) is the error-free measured value of the acceleration sensor on its X-axis at 0g (i.e. in the case of no acceleration), Setpoint(Y0) is the error-free measured value of the acceleration sensor on its Y-axis at 0g and Setpoint(Z0) is the error-free measured value of the accelerometer in its Z-axis at 0g.

Target value(1g) is the error-free measured value of the acceleration sensor with gravitational acceleration acting parallel to the sensor axis. This value should be the same for all three axes.

Uniform sampling of measurement data from the inertial measurement sensor system while the calibration device is rotating facilitates the modeling and optimization of said model function and can thus also improve the accuracy of the calibration of the inertial measurement sensor system.

The rotation of the calibration device with the electronic pen can be carried out freely in space, e.g. in the air, or preferably on a flat base/flat surface.

As also already mentioned, the housing of the calibration device can also have different cross sections/different cross-sectional profiles in sections.

The procedural steps for processing, evaluating and modeling the recorded measurement data to determine at least one zero point error in at least one axis of an acceleration sensor of the inertial measurement sensor system can be carried out, for example, by a digital processing unit of the electronic pen and/or by an external digital processing unit, with the external digital processing unit can be in communication with the electronic pen.

The method steps for processing, evaluating and modeling the recorded measurement data and the calibration of the inertial measurement sensors of the electronic pen on the basis of the evaluation of the recorded measurement data can therefore be carried out with computer support.

A digital processing unit can be understood to mean that the digital processing unit can have one or more processors, e.g. a central processing unit (CPU, Central Processing Unit).

An exemplary system for calibrating an inertial measuring sensor system of an electronic pen can therefore include a calibration device and an electronic pen with an inertial measuring sensor system. The calibration device can have the features described here by way of example.

For the sake of completeness, it should be noted that it can be advantageous if the axes of the exemplary three-dimensional inertial measurement system of the inertial measurement sensors of an electronic pen to be calibrated, e.g. the sensor axes in which accelerations and/or rotation rates can be measured, are oriented in such a way that a spatial axis / main axis of the inertial measuring system or a sensor axis is parallel to a / the longitudinal axis of the electronic pen or coincides with the / with a longitudinal axis of the electronic pen.

However, such an exemplary arrangement or orientation of the measuring sensors in the electronic pen or such an exemplary orientation of the orthogonal three-dimensional inertial measuring system of the inertial measuring sensors in relation to a / the longitudinal axis of the electronic pen is not absolutely necessary in order to use the means described herein to calibrate the to be able to carry out inertial measuring sensors.

In fact, internal tests have unexpectedly shown that even with an orientation of the orthogonal three-dimensional inertial measurement system in which a spatial axis / main axis / sensor axis of the inertial measurement system has an oblique angle, e.g. an angle of approximately up to ±3° or more, with respect to to a/to the longitudinal axis of the electronic pen, an astonishingly precise calibration of the inertial measuring sensor system can be achieved with the means described herein.

The means and methods described here as examples for calibrating or supporting the calibration of an/the inertial measuring sensor system of an electronic pen enable a previously unachieved simplification compared to known means and methods while at the same time maintaining high quality and accuracy of the calibration of an inertial measuring sensor system of an electronic pen, in particular related to the correction of zero point errors in sensor axes of inertial accelerometers.

In particular, this also means that the positions and movements of the electronic pen when it is used on a writing surface and/or when the electronic pen moves in free space can be recorded with improved accuracy.

In addition, the calibration device described herein can also serve as a storage means for a/the electronic pen.

For example, if you try to determine a zero point error of the acceleration sensor of the inertial measuring sensor system of the electronic pen by rotating the electronic pen without a calibration device described here, you will find that the scatter or the noise of the measurement data of the acceleration sensor of the inertial measuring sensor system is too large is in order to be able to carry out a technically sensible modeling between measured acceleration values and angular positions of the electronic pen, since the measured acceleration values can no longer be described, or no longer sufficiently accurately, by a sinusoidal curve as a function of the angular positions.

The measurement of measured acceleration values, in which the electronic pen is rotated about its longitudinal axis without the calibration device described herein, produces a scatter distribution of the measured acceleration values with respect to the angle of rotation that is difficult or impossible to compensate.

From this scatter distribution of the measured acceleration values, which would be obtained without the use of a calibration device described here, no meaningful connection between measured acceleration values and angular position of the electronic pen for precise calibration purposes can be derived, so that in this case the measured acceleration values do not provide a basis for a sufficiently precise calibration of the can offer inertial measuring sensors of the electronic pen.

Without the use of the calibration device described here, any existing zero point errors in the axes / measuring axes / sensor axes of the at least one acceleration sensor of the inertial measuring sensor system cannot be corrected, and the measuring sensor system of the electronic pen cannot be calibrated or not calibrated with sufficient accuracy in this regard.

The calibration device described herein and the calibration method described herein allow decoupling of shocks and vibrations of the electronic pen, which can be triggered, for example, by trembling or restless or jerky movements of the user guiding / holding the pen, and which can severely impair the quality of calibration measurements.

The calibration device described herein and the calibration method described herein also enable a decoupling of interference caused by the shape and geometry of the housing of the electronic pen, which can prevent or impede a uniform, well-defined rotation of the electronic pen about its longitudinal axis for calibration purposes, for example due to a non-rotationally symmetrical shape of the electronic pen, for example protruding and irregularly shaped structural components of the electronic pen can impair a uniform, well-defined rotation of the electronic pen about its longitudinal axis.

• 1: Beispielhafter elektronischer Schreibstift.
• 2a: Beispielhafte Seitenansicht einer Kalibriervorrichtung mit eingelegtem elektronischen Schreibstift.
• 2b: Beispielhafte perspektivische schräge Seitenansicht einer Kalibriervorrichtung mit eingelegtem elektronischen Schreibstift.
• 3a: Beispielhafte Messreihe mit kontinuierlicher Drehung ohne Kalibriervorrichtung, Messung senkrecht zur horizontalen Drehachse.
• 3b: Beispielhafte Messreihe mit Kalibriervorrichtung und kontinuierlicher Drehung, Messung senkrecht zur horizontalen Drehachse.
• 3c: Beispielhafte Messreihe mit Kalibriervorrichtung und kontinuierlicher Drehung, Messung parallel zur horizontalen Drehachse.
• 3d: Beispielhafte Messreihe mit Kalibriervorrichtung und schrittweiser Drehung.
• 4: Beispielhaftes Flussdiagram für beispielhaftes Kalibrierverfahren.
• 5: Beispielhafte Kalibriervorrichtung für schrittweise Drehung.

The following figures represent some technical aspects by way of example, which are only intended to improve understanding of the means described herein for calibrating an inertial measuring sensor system of an electronic pen.

• 1 : Exemplary electronic pen.
• 2a : Exemplary side view of a calibration device with inserted electronic pen.
• 2 B : Exemplary perspective oblique side view of a calibration device with inserted electronic pen.
• 3a : Exemplary measurement series with continuous rotation without calibration device, measurement perpendicular to the horizontal axis of rotation.
• 3b : Exemplary measurement series with calibration device and continuous rotation, measurement perpendicular to the horizontal axis of rotation.
• 3c : Exemplary measurement series with calibration device and continuous rotation, measurement parallel to the horizontal axis of rotation.
• 3d : Exemplary series of measurements with calibration device and stepwise rotation.
• 4 : Sample flow chart for sample calibration procedure.
• 5 : Exemplary step rotation calibration fixture.

The 1 FIG. 1 shows an exemplary electronic pen 1, which or whose exemplary inertial measurement sensor system 4 can be calibrated using a calibration device described herein.

As already mentioned, the electronic pen 1 can, for example, have at least one electrical voltage source (not shown) and one or more electronic components (not shown) that can be supplied by the voltage source, such as a digital control unit or a digital arithmetic unit with one or more processors, as well as have at least one communication module for receiving and transmitting data and instructions.

The inertial measuring sensor system 4 can also be supplied with electrical voltage from the voltage source.

The exemplary inertial measuring sensor system 4 can be arranged in the vicinity of the writing tip 5 of the electronic pen 1 .

As described above, the inertial measuring sensor system 4 can have acceleration sensors and/or yaw rate sensors, which can measure accelerations and/or yaw rates in a three-dimensional inertial measuring system with three spatial axes/sensor axes orthogonal to one another.

For example, the inertial measuring sensor system 4 can be arranged or oriented in such a way that a spatial axis of the inertial measuring system or a sensor axis lies parallel to the longitudinal axis 2 of the electronic pen 1 or coincides with the longitudinal axis 2 of the electronic pen 1, or that a spatial axis of the inertial measuring system or a sensor axis is not oriented parallel or only approximately parallel to the longitudinal axis 2 of the electronic pen 1 .

In the exemplary case shown, the exemplary sensor axis/spatial axis of the inertial measuring system of the inertial measuring sensor system 4, which is marked with a dashed line and with the reference number 3, is parallel to the exemplary longitudinal axis 2 of the electronic pen 1.

The exemplary writing tip or writing lead 5 can lie on the longitudinal axis 2 of the electronic pen 1 .

The 2a shows a side view of an exemplary calibration device 11 with an incorporated electronic pen 1, the electronic pen 1 being identical to that in FIG 1 illustrated electronic pen 1 can be.

The exemplary calibration device 11 has two exemplary holding means 6, 7, which can each be arranged at one end of the housing 12 of the calibration device 11.

Said exemplary holding means 6, 7 can be integrated into the housing cover 8,9 of the housing 12 of the calibration device 11.

The housing covers 8, 9 can be detachably connected to the housing 12 of the calibration device 11, so that a/the electronic pen 1 can be inserted into the calibration device 11 and removed again.

As mentioned, the exemplary housing covers 8, 9 together with the holding means can be connected to the housing 12 of the calibration device 11, for example by clamping and/or screwing and/or plugging and/or pressing and/or positive locking and/or magnetic interaction or by other detachable connection options .

For example, the housing cover 8.9 can be designed like a plug.

The exemplary holding means 6, 7 can be configured so that they can fix the recorded electronic pen 1 in the calibration device 11, ie within the housing 12 of the calibration device 11, in a predetermined alignment/orientation, ie can arrange it firmly.

The fixing of the electronic pen 1 via the holding means 6.7 can take place via detachable connections between the holding means 6.7 and the ends of the electronic pen 1.

Examples of detachable connections between the holding means 6, 7 and the electronic pen 1 can be made, for example, by clamping and/or screwing and/or pressing and/or plugging together and/or positive locking and/or magnetic interaction and/or vacuum or Suction pressure or the like can be realized.

In the exemplary case shown, the holding means 6 , 7 are configured in such a way that the electronic pen 1 is fixed centrally within the housing 12 or centrally within the calibration device 11 .

In the exemplary case shown, the holding means 6, 7 are configured in particular in such a way that the position/orientation/alignment of the electronic pen 1 held is fixed in such a way that the longitudinal axis 2 of the electronic pen 1 held is aligned with the longitudinal axis 10 of the housing 12 or with the longitudinal axis of the calibration device 11 coincides.

In the exemplary case shown, the exemplary sensor axis/spatial axis 3 of the inertial measuring system of the inertial measuring sensor system 4 is parallel to the exemplary longitudinal axis 2 of the electronic pen 1 and thus also parallel to the longitudinal axis 10 of the calibration device.

The longitudinal axis 10 of the calibration device or of the housing of the calibration device 11 also forms the axis of rotation for rotations of the calibration device with an inserted electronic pen 1 for calibrating the electronic pen 1.

As mentioned, the calibration device 11 or the housing 12 of the calibration device 11 can be rotationally symmetrical with respect to the longitudinal axis 10 of the housing 12 or with respect to the longitudinal axis of the calibration device 11 .

The 2 B shows an exemplary perspective side view of FIG 2a illustrated calibration device 11 with inserted electronic pen 1.

The reference signs of 2 B therefore correspond to the reference numerals of 2a or the 1 .

In this perspective, the exemplary rotational symmetry of the calibration device 11 or of the calibration device housing 12 in relation to the longitudinal axis 10 of the housing 12 or in relation to the longitudinal axis of the calibration device 11 can be clearly seen.

In the example shown, the calibration device 11 or the housing 12 of the calibration device 11 is cylindrical or tubular, with the housing covers 8, 9 also having a rotationally symmetrical cross section, in particular a circular cross section.

As already mentioned, however, rotationally symmetrical polygonal cross-sectional profiles are also conceivable for the calibration device 11 or for the housing 12 and the housing cover of the calibration device 11

The perspective shown also clearly shows that the holding means 6, 7 can fix the electronic pen 1 in the middle or centered within the calibration device 11, so that, for example, the longitudinal axis 2 of the electronic pen 1 held by the calibration device 11 is aligned with the longitudinal axis 10 of the Calibration device 11 or can coincide with the longitudinal axis of the calibration device housing 12 .

As also already mentioned, the inertial measuring sensor system 4 can be arranged or oriented in such a way that a spatial axis of the inertial measuring system or a sensor axis lies parallel to the longitudinal axis 2 of the electronic pen 1 or coincides with the longitudinal axis 2 of the electronic pen 1, or that a spatial axis of the inertial measuring system or a sensor axis is not oriented parallel or only approximately parallel to the longitudinal axis 2 of the electronic pen 1 .

In the exemplary case shown, the exemplary sensor axis/spatial axis 3 of the inertial measuring system of the inertial measuring sensor system 4 is parallel to the exemplary longitudinal axis 2 of the electronic pen 1.

Since in the example shown the longitudinal axis 2 of the electronic pen 1 coincides with the longitudinal axis 10 of the calibration device 11, the sensor axis/spatial axis 3 of the inertial measurement system of the inertial measurement sensors 4 of the electronic pen 1 is therefore also parallel in relation to the longitudinal axis 10 of the calibration device 11.

The 3a shows an exemplary measurement series 16 of measurement data 17 of an inertial measurement sensor system of an electronic pen without using a calibration device described herein.

The measurement data 17 represent, for example, measured acceleration values measured by the inertial measurement sensor system along a sensor axis/an axis of a/the orthogonal three-dimensional inertial measurement system of the inertial measurement sensor system of a/the electronic pen as a function of measured rotary angle positions.

The rotational angle positions can be measured, for example, by acceleration sensors of the inertial measurement sensor system, which can measure accelerations in the axes of said orthogonal three-dimensional inertial measurement system of the inertial measurement sensor system. If, for example, the force of gravity is measured along two axes of the inertial measurement system, the angle of rotation or the angular position relative to the effect of gravity can be measured using acceleration sensors.

When recording the measurement data 17, the electronic pen was rotated several times, in the present case more than six times, continuously, i.e. without specific resting or holding positions, around its longitudinal axis and during the rotating process, acceleration measurement values were measured continuously or quasi-continuously at fixed time intervals of the rotating process measured by at least one acceleration sensor of the inertial measuring sensor system of the electronic pen. The rotational speed of the calibration device 11 was about 2 seconds per revolution and the measurement frequency was 100 Hz. However, the calibration device can also be rotated at other rotational speeds.

The time curve 18 shown represents an example of the measured acceleration values measured by an acceleration sensor of the inertial measuring sensor system of the electronic pen along an exemplary sensor axis/an axis of/of the orthogonal three-dimensional inertial measuring system of the inertial measuring sensor system as a function of the angular position of the electronic pen.

The abscissa axis 13 therefore represents the course of the rotation of the electronic pen over time, and the ordinate axis 14 represents the acceleration values/measured acceleration values measured by the inertial measuring sensor system of the electronic pen along the/an exemplary sensor axis.

In this example, a periodic relationship between the measured acceleration values and the continuously changing angular position of the electronic pen over time can be identified, but the clearly recognizable scattering / the clearly recognizable noise in the measured acceleration values prevents a zero point error in one / the Sensor axis can be determined with sufficient accuracy.

As already mentioned, a vertical shift / a shift in the curve of the acceleration signal measured in an axis of an acceleration sensor along the ordinate 14 in relation to the zero line (dashed) or the zero point 15 can serve as a measure of the zero point error in said acceleration sensor axis.

However, the measured acceleration signal 18 shown is simply too noisy to be able to determine a shift, in particular a vertical shift, of the acceleration signal 18 in relation to the zero point 15 of the ordinate axis 14 with sufficient accuracy for calibration purposes of the inertial measuring sensor system of the electronic pen.

Even if one were to model the measured acceleration signal 18 by a model function, the error in determining the displacement of the acceleration signal 18 would be too great, in order to be able to use a specific displacement of the acceleration signal 18 as a basis for determining a zero point error in an acceleration sensor axis.

The acceleration signal 18 measured without a calibration device is therefore completely unsuitable for a calibration of the inertial measuring sensor system of the electronic pen.

The 3b shows an exemplary measurement series 22 of measurement data 23 of an inertial measurement sensor system of an electronic pen using a calibration device described herein.

The measurement data 23 represent, by way of example, measured acceleration values measured by the inertial measurement sensor system along a sensor axis/an axis of/the orthogonal three-dimensional inertial measurement system of the inertial measurement sensor system of a/the electronic pen as a function of measured rotational angle positions while the electronic pen is in an exemplary calibration device and this is rotates together with the electronic pen around a / the longitudinal axis of the calibration device.

Said sensor axis can correspond to the sensor axis in/along which the measurement data 17 of the measurement series 16 during the in the 3a illustrated turning process of the electronic pen were recorded.

The rotational angle positions that are assumed / traversed by the calibration device during the rotation can be measured, for example, by yaw rate sensors of the inertial measuring sensors of the electronic pen, which can measure the yaw rates in the axes of said orthogonal three-dimensional inertial measuring system of the inertial measuring sensors. Alternatively, the signal from two acceleration sensors that are orthogonal to one another and to the axis of rotation can first be calibrated in such a way that both sensors achieve the same measured value in both directions (positive and negative) if the series of measured values of the individual sensors over the angle of rotation in each case reached its maximum and its minimum. This ensures that both sensors are calibrated in terms of the zero point and sensitivity with respect to the sensor axis. A correction of the uncalibrated measured value must be set both by a constant term (proportional to the zero point error) and by a proportionality factor of the measured value. Then the angle of rotation can be calculated directly using the arctangent function of the ratio of the two mutually orthogonal, calibrated accelerometer readings.

When recording the measurement data 23, the calibration device with the electronic pen that was picked up/inserted was rotated continuously, i.e. without any specific resting or holding positions, by a little more than one revolution around a/the longitudinal axis of the calibration device, and during the rotation process, continuous or quasi-continuous rotation was performed measured acceleration values over the course of the turning process over time by at least one acceleration sensor of the inertial measuring sensor system of the electronic pen.

The time curve 24 shown represents an example of the measured acceleration values measured by an acceleration sensor of the inertial measuring sensor system of the electronic pen along an exemplary sensor axis/an axis of/of the orthogonal three-dimensional inertial measuring system of the inertial measuring sensor system as a function of the angular position of the calibration device.

The abscissa axis 19 therefore represents the angular position of the calibration device or the angular position of the electronic pen located in the calibration device.

The ordinate axis 20 represents acceleration values/measured acceleration values measured by the inertial measuring sensor system of the electronic pen along the/an exemplary sensor axis.

For the sake of completeness it should be mentioned that compared to in the 3a illustrated curve 18 of the acceleration signal, which is shown in 3b The curve 24 of the acceleration signal shown is stretched, since measurement data was only recorded over a little more than one revolution.

In addition, in the measurement series 22 the 3b the turning process of the calibration device with the electronic pen inserted is carried out with a different direction of rotation compared to the turning process, which of the measurement series 16 of 3a underlying.

The exemplary differences mentioned between the 3a and 3b However, the turning processes shown in no way preclude a comparison of the two turning processes for a better understanding of the technical aspects of the invention.

Regardless of the different number of revolutions and independent of the different direction of rotation and also independent of possible different rotational speeds, at first glance in the 3b it can be seen that when using the calibration device, the curve 24 of the measured acceleration values or of the acceleration signal is significantly lower in noise than in comparison to that in FIG 3a illustrated curve 18 without using the calibration device.

The use of the calibration device makes it possible to generate an almost noise-free acceleration signal from the acceleration sensors of the inertial measuring sensor system of the electronic pen during a rotation process of the calibration device with the electronic pen held.

The acceleration signal 24 generated using the calibration device represents an almost ideal sinusoidal curve which, as described above, can be modeled with great accuracy.

As mentioned, a vertical displacement / a displacement 25 of the curve of the acceleration signal measured in an axis of an acceleration sensor along the ordinate 20 in relation to the zero line (dashed) or the zero point 21 can serve as a measure of the zero point error in said acceleration sensor axis.

In contrast to the acceleration signal 18 without a calibration device, the acceleration signal 24 generated by using the calibration device can now be modeled with sufficient accuracy, e.g. by a model function as described above, which can include a sine function and a vertical displacement term.

An optimization algorithm as described above can then be used to find those parameter values of the parameters of the modeling function that best describe the measured curve of the recorded acceleration measurement values as a function of the rotational angle positions of the calibration device or minimize a cost function.

The determined vertical displacement/the value of the vertical displacement of the model function/model function curve that best describes the measurement data/the acceleration measurement values/the acceleration signal in relation to the zero line 21 can then serve as a measure for the zero point error, or as a zero point error value, in the corresponding acceleration sensor axis .

As also already mentioned, it was surprisingly found that a practically noise-free acceleration signal, which is suitable for calibrating the inertial measuring sensors of an electronic pen, can be generated even if the longitudinal axis or the axis of rotation of the calibration device is not exactly aligned with one/the longitudinal axis of the electronic pen and/or coincides with a sensor axis/axis of the inertial measuring system of the inertial measuring sensor system of the electronic pen or is not exactly parallel.

The 3c shows a further exemplary measurement series 28 of measurement data 29 of an inertial measurement sensor system of an electronic pen using a calibration device described herein.

In contrast to the previous figures ( 3a and 3b ), in which the measured values are shown along an axis of the acceleration sensor that is perpendicular to the axis of rotation, here you can see the values of the axis of the acceleration sensor that is approximately parallel to the axis of rotation.

The fact that the signal can again be modeled by a sine function is due to an exemplary angular error, an exemplary non-zero angular orientation that the sensor axis assumes relative to the axis of rotation. Both the individual measured values (29) and the model function (30) are shown. The model function was found by least squares minimization.

The measurement data 29 represent, for example, measured acceleration values measured by the inertial measurement sensor system along a sensor axis/an axis of an orthogonal three-dimensional inertial measuring system of the inertial measuring sensors of a / the electronic pen as a function of measured rotational angle positions, while the electronic pen is in an exemplary calibration device and this rotates together with the electronic pen around a / the longitudinal axis of the calibration device.

The abscissa axis 26 in turn represents rotary angle positions of the calibration device or the rotary angle position of the electronic pen located in the calibration device.

The ordinate axis 27 represents acceleration values/measured acceleration values measured by the inertial measuring sensor system of the electronic pen along the/an exemplary sensor axis.

It should also be mentioned that in the example shown, the acceleration sensor axis, in which the measurement data 29 was measured, is not or not exactly parallel to the axis of rotation of the calibration device, or does not coincide with the axis of rotation of the calibration device, but the curve 39 of the acceleration signal / or of the measurement data 29 has a sufficiently high signal-to-noise ratio so that a zero point error can be determined for calibration purposes.

In the 3c a model function/model function curve 30 (best-fit curve) that best describes the measurement data 29 or the profile 39 of the measurement data is also drawn in as an example.

As already explained, by modeling the measurement data 29 with the model function, the vertical displacement of the model function/model function curve 30 in relation to the zero point 40/the zero line can be determined and a zero point error value can be determined in the corresponding acceleration sensor axis.

It should also be mentioned that in the example shown, the acceleration sensor axis, in which the measurement data 29 was measured, is not or not exactly parallel to the axis of rotation of the calibration device, or does not coincide with the axis of rotation of the calibration device, but the curve 39 of the acceleration signal / or of the measurement data 29 has a sufficiently high signal-to-noise ratio so that a zero point error can be determined for calibration purposes.

The distance or the offset 32 of the axis of symmetry 31 of the model function from the zero axis 40 of the sensor signal characterizes the zero point error of the sensor. This is constant over time and therefore generates a constant shift in the measured values in one direction.

In contrast, the amplitude 33 of the model function characterizes the angular error between the axis of rotation and the axis of the sensor. The arctangent of half the amplitude, normalized by the measured value of the sensor axis when aligned parallel to the axis of gravitational acceleration, gives the angular error between the axis of rotation of the calibration device and the sensor axis.

As already mentioned, the inertial measuring sensor system of the electronic pen can be configured in such a way, or a calibration process can be carried out in such a way that measured acceleration values were only recorded in a well-defined rest position of the calibration device, i.e. the calibration device remains in a specific rotational angle position for a period of time and remains not moved.

In 3d an exemplary section of an exemplary series of measurements 34 is shown, in which the calibration device with the electronic pen inserted was rotated through 180° about its Y-axis. Reference numerals 35, 36 and 37 designate sequences of measured values integrated about one of the three sensor axes of an exemplary yaw rate sensor of the inertial measuring sensor system of the electronic pen. The expression "sequence" designates the running sum over time, which is obtained by integrating the rotational speed over time and adding all measured values up to the respective point in time of the measurement during the one rotation.

The rotation took place in the time domain 38 and it is easy to see that the rotation mainly took place around the Y-axis (sequence 37), while the other two sequences 36 and 37 show practically no change in their value over time. There are slight fluctuations in the time range 38 of the rotation alone, since the rotation did not take place exclusively around the Y axis.

In the case shown, an exemplary calibration device was used, which has a polygonal cross section and whose side surface geometry can determine the rotational angle positions/rotational angle steps and said rest positions that can be assumed during a turning process. The angle change integrated when the calibration device rotates from one side to the opposite side would be exactly π if the yaw rate sensor supplies correct values. For the exemplary calibration, a factor can therefore be calculated from π divided by the integrated angle change. Future readings can then be corrected with this factor to obtain a calibrated angular velocity.

For the sake of completeness, it should be mentioned that the 3a , 3b , 3c and 3d performed exemplary turning operations were performed on a flat surface.

However, it should be noted that using a flat surface as a base to perform the spins is purely optional.

The 4 1 shows an exemplary schematic flowchart for an exemplary method 10 for calibrating an inertial measurement sensor system of an electronic pen.

• • Ein Einlegen, 101, des elektronischen Schreibstiftes in eine wie oben beispielhaft beschriebene Kalibriervorrichtung.
• • Ein Drehen, 102, der Kalibriervorrichtung mit eingelegtem elektronischen Schreibstift um wenigstens eine Achse, z.B. eine/die Längsachse, der Kalibriervorrichtung, wobei während der Drehung der Kalibriervorrichtung mit eingelegtem elektronischen Schreibstift Messdaten der inertialen Messsensorik des elektronischen Schreibstiftes aufgenommen, 103, werden, und wobei die aufgenommenen Messdaten Beschleunigungsmesswerte von wenigstens einem Beschleunigungssensor der inertialen Messsensorik umfassen können.
• • Eine Bestimmung, 104, wenigstens eines Nullpunktfehlers in wenigstens einer Achse des Beschleunigungssensor der inertialen Messsensorik durch Auswertung der aufgenommenen Messdaten.
• • Eine Kalibrierung, 105, der inertialen Messsensorik des elektronischen Schreibstiftes auf Grundlage des wenigstens einen bestimmten Nullpunktfehlers.

The exemplary method 100 includes the following steps:

• • Insertion 101 of the electronic pen in a calibration device as described above by way of example.
• • Rotating, 102, the calibration device with the electronic pen inserted about at least one axis, e.g wherein the measured data recorded can include measured acceleration values from at least one acceleration sensor of the inertial measuring sensor system.
• • A determination 104 of at least one zero point error in at least one axis of the acceleration sensor of the inertial measurement sensor system by evaluating the recorded measurement data.
• • A calibration, 105, of the inertial measuring sensor system of the electronic pen based on the at least one determined zero point error.

The 5 FIG. 12 illustrates an exemplary brick-shaped calibration device 200, ie a calibration device having a brick-shaped housing 199. FIG.

The calibration device 200 or the calibration device housing 199 therefore has six different sides or side surfaces 201, 202, 203, 204, 205, 206 and twelve edges/edge axes/side axes 207, 208, 209, 210, 211, 212, 213, 214 , 215, 216, 217, 218 on.

The calibration device 200 can hold an electronic pen and fix it in a predeterminable alignment/orientation within the calibration device housing 199 .

However, for reasons of clarity, an electronic pen held by the calibration device 200 is not shown. However, it can be assumed, for example, that an electronic pen is accommodated and fixed in the calibration device 200 in such a way that one axis, e.g. the longitudinal axis, of the electronic pen is parallel or approximately parallel to one of the edge axes/side axes 207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218 of the calibration device 200 is aligned.

The reference number 219 designates an example of a three-dimensional orthogonal coordinate system which is spanned by the three orthogonal axes x, y, z. Said axes can, for example, correspond to the axes of the acceleration sensors and/or yaw rate sensors of the inertial measuring sensor system of an electronic pen, which can be recorded and calibrated by the calibration device 200 .

In the example shown, the x-y coordinate plane is parallel to the side surfaces 205, 206 of the calibration device 200.

The calibration device 200 is shown in an exemplary rest position, wherein the side surface 205 may serve as an exemplary bearing surface on a flat surface (not shown).

1. 1. Kippen / Drehen / Rotieren der Kalibriervorrichtung 200 aus der dargestellten (ersten) Ruheposition, in der sie auf der Fläche 201 ruht, um 180° um die Seitenachsen 208 und 212, also um eine Achse parallel zur X-Achse des Koordinatensystems 219, sodass die Kalibriervorrichtung 200 in eine Ruheposition überführt wird, in der die Seitenfläche 203 als Auflagefläche der Kalibriervorrichtung 200 dienen kann. Dies kann beispielsweise der Kalibration der Skalierung der inertialen Messsensorik entlang der Z-Achse dienen.
2. 2. Kippen / Drehen / Rotieren der Kalibriervorrichtung 200, ausgehend von einer Ruheposition in der die Kalibriervorrichtung 200 auf der Seitenfläche 205 ruht, um 180° um die Seitenachsen 207 und 209, also um eine Achse parallel zur Y-Achse des Koordinatensystems 219, sodass die Kalibriervorrichtung 200 auf Seitenfläche 206 ruht. Dies kann beispielsweise der Kalibration der Skalierung der inertialen Messsensorik entlang der X-Achse dienen.
3. 3. Kippen / Drehen / Rotieren der Kalibriervorrichtung 200, ausgehend von einer Ruheposition in der die Kalibriervorrichtung 200 auf der Seitenfläche 202 ruht, um 180° um die Seitenachsen 216 und 217, also um eine Achse parallel zur Z-Achse des Koordinatensystems 219, sodass die Kalibriervorrichtung 200 auf Seitenfläche 204 ruht. Dies kann beispielsweise der Kalibration der Skalierung der inertialen Messsensorik entlang der Y-Achse dienen.

An exemplary sequence of step-by-step rotation processes of the calibration device 200 with the electronic pen held as part of a method for calibrating an inertial measurement sensor system of a/the electronic pen can include one, some or all of the following rotation steps/rotation steps/tilting steps.

1. 1. Tilting/turning/rotating the calibration device 200 from the shown (first) rest position, in which it rests on the surface 201, by 180° around the lateral axes 208 and 212, i.e. around an axis parallel to the X-axis of the coordinate system 219, so that the calibration device 200 is transferred to a rest position in which the side surface 203 can serve as a support surface for the calibration device 200 . This can be used, for example, to calibrate the scaling of the inertial measurement sensor system along the Z axis.
2. 2. Tilting / turning / rotating the calibration device 200, starting from a rest position in which the calibration device 200 rests on the side surface 205, by 180° around the side axes 207 and 209, i.e. around an axis parallel to the Y-axis of the coordinate system 219, so that the calibration device 200 rests on side surface 206 . This can be used, for example, to calibrate the scaling of the inertial measurement sensors along the X-axis.
3. 3. Tilting / turning / rotating the calibration device 200, starting from a rest position in which the calibration device 200 rests on the side surface 202, by 180° around the side axes 216 and 217, i.e. around an axis parallel to the Z-axis of the coordinate system 219, so that the calibration device 200 rests on side surface 204 . This can be used, for example, to calibrate the scaling of the inertial measurement sensor system along the Y axis.

As described above, measurement data from the acceleration sensors and yaw rate sensors can be collected during the exemplary turning processes and/or in the rest positions in order to calibrate the inertial measurement sensors of the electronic pen.

There follow 9 pages with the 1 , 2a , 2 B , 3a , 3b , 3c , 3d , 4 and 5 .

1

Beispielhafter elektronischer Schreibstift

2

Beispielhafte Längsachse des elektronischen Schreibstiftes (gestrichelte Line mit erster Strichlänge)

3

Beispielhafte Sensorachse / Raumachse eines beispielhaften dreidimensionalen Inertialmesssystems der inertialen Messsensorik des elektronischen Schreibstiftes (gestrichelte Line mit zweiter Strichlänge)

4

Beispielhafte inertiale Messsensorik

5

Beispielhafte Schreibspitze / Schreibmine

6

Beispielhaftes (erstes) Haltemittel / Haltelement / Halterung

7

Beispielhaftes (zweites) Haltemittel / Haltelement / Halterung

8

Beispielhaftes (erstes) Ende des Gehäuses der Kalibriervorrichtung / Gehäusedeckel

9

Beispielhaftes (zweites) Ende des Gehäuses der Kalibriervorrichtung / Gehäusedeckel

10

Beispielhafte Längsachse der Kalibriervorrichtung / Längsachse des Gehäuses der Kalibriervorrichtung / Längsachse der Kalibriervorrichtung / Rotationsachse der Kalibriervorrichtung

11

Beispielhafte Kalibriervorrichtung

12

Beispielhaftes Gehäuse der Kalibriervorrichtung

13

Beispielhafte Abszissenachse für Drehwinkelpositionen oder Drehwinkel von elektronischem Schreibstift

14

Beispielhafte Ordinatenachse für gemessene Beschleunigungswerte / Beschleunigungsmesswerte

15

Beispielhafter Nullpunkt der Ordinatenachse für gemessene Beschleunigungswerte/Nulllinie

16

Beispielhafte Messreihe von Beschleunigungswerte ohne Verwendung einer Kalibriervorrichtung

17

Beispielhafter Messpunkt / Beschleunigungsmesswert

18

Beispielhafter (zeitlicher) Verlauf der Messpunkte / Beschleunigungsmesswerte / Beschleunigungssignal

19

Beispielhafte Abszissenachse für Drehwinkelpositionen oder Drehwinkel von Kalibriervorrichtung, bzw. für Drehwinkelpositionen oder Drehwinkel von elektronischem Schreibstift

20

Beispielhafte Ordinatenachse für gemessene Beschleunigungswerte / Beschleunigungsmesswerte

21

Beispielhafter Nullpunkt der Ordinatenachse für gemessene Beschleunigungswerte/Nulllinie

22

Beispielhafte Messreihe von Beschleunigungswerte mit Verwendung einer Kalibriervorrichtung

23

Beispielhafter Messpunkt / Beschleunigungsmesswert

24

Beispielhafter (zeitlicher) Verlauf der Messpunkte / Beschleunigungsmesswerte / Beschleunigungssignal

25

Beispielhafte vertikale Verschiebung

26

Beispielhafte Abszissenachse für Drehwinkelpositionen oder Drehwinkel von elektronischem Schreibstift

27

Beispielhafte Ordinatenachse für gemessene Beschleunigungswerte / Beschleunigungsmesswerte

28

Beispielhafte Messreihe von Beschleunigungswerte mit Verwendung einer Kalibriervorrichtung

29

Beispielhafter Messpunkt / Beschleunigungsmesswert (an einer bestimmten Ruheposition und einer bestimmten Drehwinkelposition in einer Folge von schrittweisen Drehwinkelschritten)

30

Beispielhafte die Messreihe am besten beschreiben Modellfunktion (Best-Fit-Model)

31

Beispielhafte Symmetrieachse der Modellfunktion

32

Beispielhafter Abstand bzw. Offset der Symmetrieachse der Modellfunktion von der Nullachse / beispielhafter Nullpunktfehler / beispielhafte Nullpunktabweichung der Modellfunktion des Verlaufs der Messpunkte / Beschleunigungsmesswerte / des Beschleunigungssignals

33

Beispielhafte Amplitude der Modellfunktion des Verlaufs der Messpunkte / Beschleunigungsmesswerte / des Beschleunigungssignals

34

Beispielhafte Messreihe von aufintegrierten Drehratenwerten eines Drehratensensors einer inertialen Messsensorik eines elektronischen Schreibstiftes für eine beispielhafte Drehung einer Kalibriervorrichtung mit eingelegtem elektronischen Schreibstift um 180°

35

Beispielhafter Verlauf / beispielhafte Folge der aufintegrierten X-Werte des Drehratensensors

36

Beispielhafter Verlauf / beispielhafte Folge der aufintegrierten Z-Werte des Drehratensensors

37

Beispielhafter Verlauf / beispielhafte Folge der aufintegrierten Y-Werte des Drehratensensors

38

Beispielhafter zeitlicher Bereich, in der die Kalibriervorrichtung um 180° gedreht wird/wurde

39

Beispielhafter (zeitlicher) Verlauf der Messpunkte / Beschleunigungsmesswerte / des Beschleunigungssignals

40

Beispielhafte Nulllinie, beispielhafter Nullpunkt

41

Beispielhafte Abszissenachse, beispielhafte Zeitachse, beispielhafte chronologische Abfolge von Messpunkten

42

Beispielhafte Ordinatenachse, beispielhaftes aufintegriertes Drehratensensorsignal / aufintegrierte Drehratenmesswerte, beispielhafte Drehwinkel, beispielhafte Messeinheit Radiant (rad)

100

Beispielhaftes Verfahren zur Kalibrierung einer inertialen Messsensorik eines elektronischen

101, 102, 103, 104, 105

Beispielhafte Verfahrensschritte

199

Beispielhaftes quaderförmiges Gehäuse einer Kalibriervorrichtung

200

Beispielhafte quaderförmige Kalibriervorrichtung

201, 202, 203, 204, 205, 206

Beispielhafte Seiten / Seitenflächen der Kalibriervorrichtung / des Kalibriervorrichtungsgehäuses

207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218

Beispielhafte Kantenachsen / Seitenachsen der Kalibriervorrichtung / des Kalibriervorrichtungsgehäuses

219

Beispielhaftes dreidimensionales orthogonales Koordinatensystem

The reference symbols are assigned as follows.

1

Exemplary electronic pen

2

Exemplary longitudinal axis of the electronic pen (dashed line with first line length)

3

Exemplary sensor axis / spatial axis of an exemplary three-dimensional inertial measurement system of the inertial measurement sensors of the electronic pen (dashed line with second line length)

4

Exemplary inertial measurement sensors

5

Exemplary writing tip / writing refill

6

Exemplary (first) holding means/holding element/mount

7

Exemplary (second) holding means/holding element/mount

8th

Exemplary (first) end of the housing of the calibration device / housing cover

9

Exemplary (second) end of the calibration device housing / housing cover

10

Exemplary longitudinal axis of the calibration device / longitudinal axis of the housing of the calibration device / longitudinal axis of the calibration device / axis of rotation of the calibration device

11

Exemplary calibration device

12

Exemplary housing of the calibration device

13

Exemplary abscissa axis for angle of rotation positions or angle of rotation of an electronic pen

14

Exemplary ordinate axis for measured acceleration values / measured acceleration values

15

Exemplary zero point of the ordinate axis for measured acceleration values/zero line

16

Exemplary measurement series of acceleration values without using a calibration device

17

Exemplary measurement point / acceleration measurement value

18

Exemplary (chronological) course of the measuring points / acceleration measured values / acceleration signal

19

Exemplary abscissa axis for angle of rotation positions or angle of rotation of calibration device, or for angle of rotation positions or angle of rotation of electronic pen

20

Exemplary ordinate axis for measured acceleration values / measured acceleration values

21

Exemplary zero point of the ordinate axis for measured acceleration values/zero line

22

Exemplary measurement series of acceleration values using a calibration device

23

Exemplary measurement point / acceleration measurement value

24

Exemplary (chronological) course of the measuring points / acceleration measured values / acceleration signal

25

Exemplary vertical shift

26

Exemplary abscissa axis for angle of rotation positions or angle of rotation of an electronic pen

27

Exemplary ordinate axis for measured acceleration values / measured acceleration values

28

Exemplary measurement series of acceleration values using a calibration device

29

Exemplary measurement point / acceleration measurement value (at a specific rest position and a specific rotational angle position in a sequence of incremental rotational angle steps)

30

Examples best describe the series of measurements model function (best-fit model)

31

Exemplary axis of symmetry of the model function

32

Exemplary distance or offset of the symmetry axis of the model function from the zero axis / exemplary zero point error / exemplary zero point deviation of the model function of the course of the measuring points / acceleration measured values / the acceleration signal

33

Exemplary amplitude of the model function of the progression of the measurement points / acceleration measurement values / the acceleration signal

34

Exemplary measurement series of integrated yaw rate values of a yaw rate sensor of an inertial measuring sensor system of an electronic pen for an exemplary rotation of a calibration device with an inserted electronic pen by 180°

35

Exemplary progression / exemplary sequence of the integrated X values of the yaw rate sensor

36

Exemplary progression / exemplary sequence of the integrated Z values of the yaw rate sensor

37

Exemplary progression / exemplary sequence of the integrated Y values of the yaw rate sensor

38

Exemplary time range in which the calibration device is/was rotated by 180°

39

Exemplary (chronological) course of the measuring points / acceleration measured values / the acceleration signal

40

Exemplary zero line, exemplary zero point

41

Exemplary abscissa axis, exemplary time axis, exemplary chronological sequence of measurement points

42

Exemplary ordinate axis, exemplary integrated yaw rate sensor signal / integrated yaw rate measured values, exemplary angle of rotation, exemplary measurement unit radian (rad)

100

Exemplary method for calibrating an inertial measuring sensor system of an electronic

101, 102, 103, 104, 105

Exemplary process steps

199

Exemplary cuboid housing of a calibration device

200

Exemplary cuboid calibration device

201, 202, 203, 204, 205, 206

Exemplary sides/faces of the calibrator/calibrator housing

207, 208, 209, 210, 211, 212, 213, 214, 215, 216, 217, 218

Exemplary edge axes / side axes of the calibrator / calibrator housing

219

Exemplary three-dimensional orthogonal coordinate system

Claims (14)

Calibration device (11) for calibrating an inertial measuring sensor system (4) of an electronic pen (1), comprising: a housing (12) for receiving an electronic pen (1), wherein the housing (12) has at least one holding means (6, 7) for fixing an electronic pen (1) accommodated by the housing (12) within the housing (12), the at least one holding means (6, 7) being configured for this purpose, to fix a received electronic pen (1) centrally within the housing (12) and the longitudinal axis (2) of the received electronic pen is oriented parallel to the longitudinal axis (10) of the housing (12), and wherein the cross section of the housing is rotationally symmetrical and/ or is cylindrical or polygonal, e.g., rectangular, and/or wherein the housing is cubic or parallelepipedal. Calibration device (11) according to the preceding claim, wherein the at least one holding means (6, 7) is configured to fix a received electronic pen (1) in such a way that the longitudinal axis (2) of the received electronic pen is aligned with the longitudinal axis (10) of the housing (12) collapses. Calibration device (11) according to one of the preceding claims, wherein the holding means is flexible and/or wherein the housing (12) has at least two holding means (6, 7) and wherein one holding means is arranged at each end of the housing and/or wherein the holding means fills the majority of the interior of the housing of the (12) calibration device (11). Calibration device (11) according to one of the preceding claims, wherein the at least one holding means (6, 7) is integrated into a housing cover (8, 9) or housing base of the housing and/or wherein the housing (12) is permeable to electromagnetic waves. Method (100) for calibrating an inertial measuring sensor system of an electronic pen, comprising: inserting (101) the electronic pen into a calibration device according to one of the preceding claims; Rotating (102) the calibration device with the electronic pen inserted about at least one axis of the calibration device, measurement data of the inertial measurement sensor system of the electronic pen being recorded (103) during the rotation of the calibration device with the electronic pen inserted, and the measurement data recorded being measured acceleration values from at least one acceleration sensor and/or yaw rate measured values from at least one yaw rate sensor of the inertial measuring sensor system; Determination (104) of at least one zero point error in at least one axis of the acceleration sensor of the inertial measurement sensor system by evaluating the recorded measurement data; Calibration (105) of the inertial measuring sensor system of the electronic pen on the basis of the at least one determined zero point error. Method (100) according to the preceding claim, wherein the determination of at least one zero point error in at least one axis of the acceleration sensor of the inertial measurement sensor system by evaluating the recorded measurement data includes modeling the recorded acceleration measurement values as a function of the rotational angle positions assumed during the rotation of the calibration device by a trigonometric function, and wherein the at least one zero error in at least one axis of the accelerometer is determined based on a determined offset of the modeled trigonometric function from zero. Method (100) according to the preceding claim, wherein the trigonometric function for modeling the recorded acceleration measurement values as a function of the rotational angle positions of the calibration device comprises a sine function. The method (100) according to the preceding claim, wherein before the modeling of the recorded acceleration measurement values, the angular orientation of the coordinate system of the inertial measurement sensor system in relation to the gravity vector is determined by a trigonometric function from the measurement data of the inertial measurement sensor system of the electronic pen. Method (100) according to one of the preceding method claims, wherein before the calibration device is rotated with the electronic pen inserted, the calibration device is not moved in order to determine a zero point of a yaw rate sensor/to determine zero points of yaw rate sensors of the inertial measurement sensor system and/or wherein the rotation of the calibration device inserted electronic pen is carried out about at least one axis of the calibration device on a flat surface. The method (100) according to any one of the preceding method claims, wherein the rotation comprises a sequence of rotation processes, with the calibration device being in a rest position between two consecutive rotation processes, in which the calibration device does not move for a predetermined period of time, and with measurement data from the inertial measurement sensors be recorded in the rest position of the calibration device. Method (100) according to one of the preceding method claims, wherein the turning of the calibration device (200) with the electronic pen inserted comprises a sequence of turning processes which comprises at least one turning process with a rotation of the calibration device by 180°. The method (100) according to the preceding claim, wherein the calibration device (200) comprises a housing with six side faces and the turning of the calibration device with an inserted electronic pen comprises a sequence of turning processes in which each of the side faces at least once assumes an orientation in which the respective side surface can serve as a bearing surface of the calibration device on a flat surface. Method (100) according to one of the preceding method claims, wherein the evaluation of the recorded measurement data for determining at least one zero point error in at least one axis of the acceleration sensor of the inertial measurement sensor system is carried out by a digital processing unit of the electronic pen and/or by an external digital processing unit, the external digital Arithmetic unit is in communication with the electronic pen. System comprising a calibration device (11) according to one of the preceding device claims and an electronic pen (1) with inertial measuring sensors.

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