DE102022124958A1 - Method for detecting a relative rotation angle position and magnetic rotation angle sensor device - Google Patents

Abstract

The invention relates to a method for detecting a relative rotation angle position between a sensor arrangement (3) and a magnet arrangement of a rotation angle transmitter device (1), wherein the sensor arrangement (3) and the magnet arrangement are arranged to be rotatable relative to one another about an axis of rotation (A), and the magnet arrangement has a multipolar , field-emitting permanent magnets and the sensor arrangement (3) is designed to detect at least two different field components in the form of assigned measurement signals, with the sensor arrangement (3) producing a respective periodic, in particular sine- or cosine-like, course when the sensor and magnet arrangement move relative to each other the field components are detected via the assigned measurement signals, and a rotation angle indicating the relative rotation angle position is determined on the basis of the detected different field components. The method according to the invention is characterized in that at least two sensor devices (30a, 30b, 30c, 30d) of the sensor arrangement (3) are arranged circumferentially spaced apart, and from each sensor device (30a, 30b, 30c, 30d)

Description

The invention relates to a method for detecting a relative rotation angle position between a sensor arrangement and a magnet arrangement of a magnetic rotation angle sensor device, wherein the sensor arrangement and the magnet arrangement are arranged to be rotatable relative to one another about an axis of rotation and the magnet arrangement comprises a multipolar, field-emitting permanent magnet and the sensor arrangement for detecting at least two different Field components are designed in the form of assigned measurement signals, with the sensor arrangement detecting a respective periodic, in particular sine or cosine-like course of the field components via the assigned measurement signals during a relative rotational movement of the sensor and magnet arrangement, and a rotation angle indicating the relative rotation angle position on the based on the different field components recorded. The invention further relates to a magnetic rotation angle sensor device for carrying out such a method.

Such a method can generally be carried out without contact, so that there is a high application potential, for example in the industrial sector, in particular in the processing industry such as metal construction, and/or in the automotive sector. Such a conventional method or a conventional magnetic rotary angle sensor device for carrying out such a method is, for example, in the German laid-open publication DE 10 2018 20 665 A1 described. In the conventional method, the sensor arrangement detects a radial component and a tangential component of the measuring field provided by the permanent magnet. It is generally known that the sensor arrangement can detect a respective periodic, in particular sine or cosine-like course of the field components during a relative rotational movement of the sensor and magnet arrangement, so that the determination of the angle of rotation from the measured field components by executing an arctan function Measurement signals can be carried out. In the known rotary angle sensor device DE 10.2018 220 665 A1 A gear selector lever can be moved between predetermined positions. The selector lever is motion-coupled to a permanent magnet through a non-rotatable mounting on a shaft connected to the selector lever. The shaft with the magnet is arranged to be rotatable about an axis of rotation defined by the selector lever. The sensor arrangement comprises a base support, with the magnet and shaft being rotatably mounted about the axis of rotation relative to the base support and thus to the sensor arrangement. In the described embodiment, the magnet is magnetized parallel to the axis of rotation and thus generates a magnetic measuring field that is coupled to the magnet in a rotationally fixed manner. The sensor detects a radial component and a tangential component of the measuring field, the angle of rotation being determined from the detected radial component and the detected tangential component using an arctan function, applied to the quotient of the two measuring field components. In the publication mentioned, it is pointed out that the courses of the radial component and the tangential component of the measuring field at the location of the sensor arrangement are not ideally sinusoidal or cosinusoidal due to a number of reasons, so that a re-evaluation using such a TAN function is not exactly the same provides the actual angle of rotation of the magnet. To solve the problem described, it is proposed in the stated prior art to vary the axial distance and/or the radial distance of the sensor from the axis of rotation using comparatively complex FEM analyzes until a combination of axial distance and radial distance is found at which the deviation between the determined angle of rotation and the actual angle of rotation is minimized.

However, it has been found that the conventional method described in the stated prior art, using complicated calculations, enables the error in determining the desired angle of rotation to be reduced, but the resulting error always remains in relation to a full rotation of the magnet through 360 ° is still in the range of around 10°. In addition, it has been found that certain field transmitter magnets, e.g. uniaxially anisotropic magnets such as sintered magnets, but also isotropic magnets, can generate a measuring field that deviates greatly from a sinusoidal shape, so that they are also unsuitable for the conventional determination of the field angle described.

In this respect, the present invention is based on the object of further improving the described conventional method for detecting a relative rotation angle position between a sensor arrangement and a magnet arrangement in order to reduce the error dimension of the determined angle of rotation to the real angle of rotation between the sensor arrangement and magnet arrangement or to use the previously used for the To enable determination of a rotation angle of unsuitable magnets.

The present application solves this problem by a method for detecting a relative rotation angle position between a sensor arrangement and a magnet arrangement of a rotation angle transmitter device, the sensor arrangement and the magnet arrangement being relative to one another a rotation axis are rotatably arranged, and the magnet arrangement comprises a multipolar, field-emitting permanent magnet and the sensor arrangement is designed to detect at least two different field components in the form of assigned measurement signals, with the sensor arrangement resulting in a respective periodic, in particular, rotational movement of the sensor and magnet arrangement sine or cosine-like course of the field components is detected via the assigned measurement signals, and a rotation angle indicating the relative rotation angle position is determined on the basis, ie depending on, of the different field components detected. The method according to the invention is characterized in that at least two sensor devices of the sensor arrangement are arranged circumferentially spaced apart and signals are determined by each sensor device which depend on the different field components present locally, ie at the location of the respective sensor device, with at least one sum signal and one difference signal of these signals is determined, and the angle of rotation is determined depending on the sum signal and the difference signal.

The method according to the invention is based on the inventor's surprising finding that in the case of two field components relevant to determining the angle of rotation or their associated measurement signals, the respective components of higher harmonics, in particular components of odd-numbered harmonics, are of the same order of magnitude or have similar values in terms of absolute value, while they are different in terms of sign and phase position. Based on this knowledge, the invention proposes to combine or add individual signals from the sensor devices with a correspondingly appropriate phase shift in order to minimize the proportion of higher harmonics in the measurement signals, so that only a small difference occurs when determining the angle of rotation on the basis of the combined measurement signals Angle error results due to an improved approximation of the combined measurement signals to an ideal sine or cosine function. The invention therefore proposes to determine at least one sum signal and one difference signal, in each of which a compensation of signal components of higher harmonics in the course of the field components during the rotary movement can be achieved, so that the angle of rotation depends on the respective sine or cosine function approximate sum signal and difference signal can be determined. With the method according to the invention, it is now possible, depending on the embodiment, to significantly reduce the angular error when detecting a relative rotational angle position between a sensor arrangement and a magnet arrangement compared to the angular error in the conventional method described, so that, depending on the embodiment, this can easily be <3 .5°, in particular <1.5°. Furthermore, with the method according to the invention it is now also possible to use inexpensive permanent magnets to determine an angle of rotation. The method according to the invention is particularly suitable for determining the angle of rotation when using permanent magnets based on sintered magnets, which are usually in anisotropic form, with which generally no magnetization can be achieved that leads to sinusoidal field shapes. The same applies to many types of isotropic sintered magnets, as well as to various forms of plastic-bonded magnets, which, as described, can lead to significant, intolerable angular errors when carrying out conventional methods for detecting an angle of rotation.

The measuring fields generated with such magnets often have field components with a trapezoidal character, while the other field component can have a shape that can ideally correspond to a triangular shape, with the method according to the invention for combining such field curves in phase with a relative rotation of the magnet arrangement and sensor arrangement by one predetermined axis of rotation an adjustment of the respective combined signal to a purely sinusoidal or cosinusoidal curve signals can be generated or are generated, which lead to rotation angle determinations in further processing, which have only a small error. Using the method according to the invention, the desired angle of rotation can be determined without complex calculation and adjustment steps, which reduces the hardware effort for designing a device to implement the method.

Depending on the embodiment, the at least two different field components can be a tangential and an axial field component, which are to be understood in relation to the axis of rotation. In another embodiment, the at least two different field components can also be a tangential and a radial field component, again with respect to the axis of rotation. The at least two different field components at the respective location of the sensor device are detected by the sensor device in the form of assigned measurement signals. Depending on the embodiment, these measurement signals can be in analog or digital form, whereby an originally analog measurement signal can be digitized as part of further processing, so that a subsequent determination of the angle of rotation can be carried out, in particular by means of a microprocessor, due to the process associated with the method according to the invention reduced computing effort but also with a logic circuit adapted to the necessary arithmetic operations.

The “angle of rotation” specification can represent a value that directly reflects the angle of rotation you are looking for, for example in radians. However, it can also represent a value that is clearly correlated with such a direct angle indication.

Depending on the embodiment, the signals assigned to the different field components can be direct measurement signals from sensor devices of the sensor arrangement, or signals determined, in particular calculated, from the measurement signals, for example gradient signals.

The circumferential spacing of the at least two sensor devices of the sensor arrangement, in particular the two sensor devices, can mean the circumferential spacing with respect to the axis of rotation. In particular, the spacing between, for example, two sensor devices can relate to a spacing on a circular arc, wherein the axis of rotation can run through the center or the center of the circular arc. In this respect, the radial distance of the sensor devices from the axis of rotation can be identical.

Additional features and developments of the present invention that are essential to the invention are specified in the general description, the figures, the description of the figures and the subclaims.

According to the invention, the desired angle of rotation can be determined as a function of the sum signal and the difference signal. To generate the sum signal, this can be formed from two summands, the first summand being a signal from a first of the at least two sensor devices assigned to a first of the two magnetic field components and the second summand being a signal assigned to a second of the two magnetic field components from a second of the at least is two sensor devices.

In an embodiment in which the signals for generating the sum signal are the direct measurement signals, the summand can be a measurement signal from a first sensor device assigned to the first magnetic field component and the second summand can be a measurement signal from the second sensor device assigned to the second magnetic field component. In this embodiment, at least two measurement signals, in particular two measurement signals, are combined to generate the sum signal, whereby these two measurement signals can relate to different field components of different sensor devices that are in particular circumferentially spaced from one another. In the sum generation described, such signals are combined in phase and with a sign, so that, as explained above, the higher harmonics of the two combined signals essentially compensate for each other, so that the sum signal can have a curve adapted to a pure sinusoidal shape. The addends to form the sum signal are preferably recorded at the same time, so that a combination of the signals with a predetermined phase position can be carried out. On the other hand, a phase shift caused by a possible time delay in recording the measurement signals can expediently be taken into account when combining the signals.

The difference signal used to determine the angle of rotation can expediently represent a combination of two signals similar to the sum formation just described above, in particular a combination of measurement signals in which the combined signals cancel each other out again with respect to the higher harmonics. In particular, the difference signal can be formed by subtracting a subtrahend signal from a minuend signal, one of the latter two signals, i.e. H. Subtrahend signal and minute end signal, a signal assigned to the first of the two magnetic field components from the second of the at least two sensor devices spaced apart from one another and the other of the latter two signals, i.e. H. Subtrahend signal and minute end signal, a signal assigned to the second of the two magnetic field components from the first of the at least two sensor devices spaced apart from one another. In order to maintain a predetermined phase relationship between the subtrahend signal and the minute end signal, the signals can expediently be detected or determined at the same time. On the other hand, a phase shift caused by a possible time delay in recording the measurement signals can expediently be taken into account when combining the signals.

Due to the described method for generating combination signals that are dependent on the respective field components (e.g. in the form of a sum signal and a difference signal), which have a course that approximates a pure sine or cosine shape, an arctan function can advantageously be used to determine the angle of rotation can be applied to a quotient in which the dividend can be formed by the sum signal and the divisor by the difference signal. Complicated and time-consuming compensation calculations can be omitted, so that with With the method according to the invention, the requirements for signal processing, in particular digital signal processing, can be reduced.

The method according to the invention can be carried out using multi-pole magnets, in particular multi-pole axially or diametrically magnetized magnets. Depending on the embodiment, this number of poles np can always be even and greater than ≥ 2, with a number of poles of np = 4, np = 6 and in particular np = 8 being particularly useful.

To determine the angle of rotation, it can expediently be provided that the result of applying the arctan function to the quotient is multiplied by the quotient 2/np, where np in turn indicates the number of poles of the magnet of the magnet arrangement. In order to keep the determination of the angle of rotation in the calculation described simple and to avoid possible phase adjustments of the signals assigned to the field components, it can expediently be provided that the two sensor devices of the sensor arrangement are circumferentially spaced by a center angle α of a = π / np on an imaginary arc, in particular be arranged in a circular arc, whereby np in turn indicates the number of poles of the magnet arrangement. Preferably, this circular arc can be oriented in such a way that the axis of rotation runs through the center of the circular arc, i.e. both sensor devices are arranged at a respective radius distance from the center of the circle, which is essentially the same.

Depending on the design of the measuring field, i.e. H. of the field generated by the magnet arrangement, it can be provided that a tangential and an axial field component or a tangential and a radial field component are detected as different field components of the permanent magnet, so that a field detection optimized for the respective application can be realized.

In principle, the result of the method according to the invention can be falsified by the occurrence of an external field in the area of the sensor arrangement. In order to minimize such an effect of external fields on the method according to the invention, it can expediently be provided that the sensor devices of the sensor arrangement for providing external field compensation are each designed as a gradient sensor device, each comprising two radially spaced sensors arranged circumferentially at approximately the same center angle for each field component, via which measurement signals assigned to the respective field components are recorded. Such gradient sensor devices can, assuming that the external field at the location of the two radially spaced sensors of a sensor device is identical, provide external field-independent signals for each field component by forming the difference, so that with the external field compensated signals by each gradient sensor device a (gradient) signal assigned to the first field component and a (gradient) signal assigned to the second field component is provided as a signal basis for the determination of the sum signal described above and the difference signal described above on the basis of which then or depending on which, in particular by applying an arctan function to the quotient of the sum signal and the difference signal , the desired angle of rotation can be calculated. In this embodiment, the sum signal and the difference signal are not determined by direct measurement signals of the respective field component, but rather on the basis of the described (gradient) signals from the gradient sensor devices.

The above object is further achieved on the device side by a rotation angle sensor device for detecting a relative rotation angle position with the features of claim 11. The rotary angle encoder device according to the invention has a sensor arrangement and a magnet arrangement, which are arranged to be rotatable relative to one another about an axis of rotation, the magnet arrangement comprising a multipolar, field-generating permanent magnet and the sensor arrangement is designed to detect different field components in the form of assigned measurement signals, and by the sensor arrangement at a Relative rotational movement of the sensor and magnet arrangement, a respective periodic, in particular sine or cosine-like course of the field components can be detected via the assigned measurement signals and a rotation angle indicating the relative rotation angle position can be determined on the basis of the detected different field components by means of a signal processing device. The rotary angle sensor device according to the invention is characterized in that at least two sensor devices of the sensor arrangement are arranged circumferentially spaced apart, in particular circumferentially spaced apart on a circular arc, whereby the axis of rotation can run through the center of the circular arc, and each sensor device determines signals which are different from the locally present ones Field components depend, with at least one sum signal and a difference signal of these signals being determined for the respective compensation of signal components of higher harmonics in the course of the signals during the relative rotational movement, the signal processing device being designed and set up to determine the angle of rotation as a function of the sum signal and the difference signal.

Depending on the embodiment, the magnet arrangement can have an axially, radially or diametrically magnetized, multipolar permanent magnet, in particular a 2-pole, 4-pole, 6-pole or even 8-pole permanent magnet. In certain embodiments, the magnet arrangement can also comprise a permanent magnet with an even higher number of poles. The permanent magnet of the magnet arrangement can in particular be ring-shaped or cylindrical with an axis, wherein the arrangement within the angle of rotation arrangement can be such that this axis is oriented coaxially to the axis of rotation.

The sensor devices of the sensor arrangement can be designed or include, for example, a Hall sensor, a GMR sensor or a TNR sensor, with each of the sensor devices being designed to detect the two different field components, for example by providing a 2D or 3D sensor which is used for simultaneous detection of the at least two different field components or by providing a respective individual sensor for detecting one field component and a sensor for detecting the other field component, i.e. by providing a pair of sensors for each of the sensor devices.

In one embodiment, it can be provided that the sensor arrangement is arranged to be rotatable about the axis of rotation relative to the magnet arrangement, i.e. the magnet arrangement is arranged, for example, in a stationary manner relative to a housing of the rotary angle sensor device. To simplify the signal routing, however, it can also be provided that the magnet arrangement can be arranged to be rotatable about the axis of rotation on a support that is stationary, for example relative to a housing of the rotary angle sensor device, which carries the sensor arrangement and the magnet arrangement is thus rotatably mounted relative to the sensor arrangement. For example, it can be provided that the permanent magnet of the magnet arrangement is designed to be ring-shaped or cylindrical, as shown, whereby the permanent magnet can be fixedly arranged on an actuable rotary shaft and the shaft axis can run coaxially to the rotary axis. In this respect, the sensor devices and the signal processing device can be arranged in a stationary manner on the rotary angle sensor device. In this respect, a “stationary arrangement” means a respective arrangement, such as a sensor arrangement or magnet arrangement, which is immovable relative to the rotary angle sensor device, in particular a housing of the rotary angle sensor device.

To simplify the formation of the sum signal and the difference signal, on the basis of or depending on which the angle of rotation can be determined, it can expediently be provided that the sensor devices of the sensor arrangement are arranged on an imaginary circular arc, circumferentially spaced by a center angle β of β = π / np are, where np indicates the number of poles of the magnet of the magnet arrangement and the axis of rotation can run through the center of the circle arc.

The different field components, which are detected or measured by the respective sensor device of the sensor arrangement, can be oriented perpendicular to one another, for example a tangential and an axial field component or a tangential and a radial field component with respect to the axis of rotation.

Depending on the embodiment of the rotary angle sensor device according to the invention, the sensor arrangement and magnet arrangement, which are rotatably arranged relative to one another, can be arranged differently from one another. In such embodiments, in which the sensor arrangement or the sensor devices are arranged axially spaced from the magnet arrangement or the magnet, it can expediently be provided that the sensor arrangement or the sensor devices is arranged radially within the magnet arrangement, in particular approximately centrally to the radial thickness of the magnet to optimize the field components detected by the sensor device. In this arrangement it can be provided that the circumferentially spaced sensor devices lie within a plane, whereby this plane can run approximately perpendicular to the axis of rotation.

In embodiments in which the sensor arrangement is arranged at a radial distance, in particular radially on the outside, from the magnet arrangement or from the magnet, it can be provided that the sensor devices which are spaced apart from one another are arranged on the surface of a cylindrical surface at an identical axial height of the magnet, so that the sensor devices have the same radial Can have a distance from the axis of rotation. In this embodiment it can be provided that the sensor devices are placed approximately half the axial height of the magnet.

However, it is also within the scope of the invention to arrange the sensor devices of the sensor arrangement both radially and axially at a distance from the particularly ring- or cylindrical magnet.

The signal processing device of the rotary angle encoder device according to the invention can, for example, comprise a microprocessor which is coupled to the respective output of the sensor devices and the measurement signals received depending on the output of the sensor devices digitizes log signals or receives digital signals directly and carries out the necessary determinations or calculations to determine the described sum signal and difference signal. Depending on the embodiment, the signal processing device can be set up to form the arcgantens function of a quotient formed by the sum signal and the difference signal. In another embodiment, the signal processing device can also be designed as a processing circuit, so that it does not have to have a microprocessor.

In order to avoid the influence of magnetic interference fields, the sensor arrangement of the rotary angle sensor device according to the invention can have respective sensor devices which are designed as gradient sensor devices. Such a gradient sensor device can have two sensors for each of the two field components, the measurement signals of which are internally subtracted to eliminate the respective external field influence on the measurements. In this respect, each gradient sensor device can have a total of four sensors, with two sensors each detecting the field of one of the two field components. Preferably, the rotation angle sensor device according to the invention can have two such gradient sensor devices, which can be arranged circumferentially spaced apart, in particular circumferentially spaced on a circular arc. According to the invention, the output signals of these gradient sensor devices can be processed like the measurement signals of the conventional sensor devices described above to determine the sum signal and the difference signal and to subsequently determine the desired angle of rotation.

• 1a in einer reduzierten Prinzipskizze eine erfindungsgemäße Drehwinkelgebereinrichtung mit einem ringförmigen, axial polarisierten, 4-poligen Sinterferrit-Magneten mit stirnseitig zum Magneten angeordneter und axial beabstandeter Sensoranordnung in einer Stirnseitenansicht;
• 1b die Drehwinkelgebereinrichtung der 1a in einer Radialansicht;
• 2 der Verlauf der von einer Sensoreinrichtung der Sensoranordnung gemäß 1a erfassten tangentialen und axialen Feldkomponenten bei einer Drehung des Magneten um die Drehachse A relativ zur ortsfesten Sensoranordnung;
• 3 die Anordnung der beiden umfänglich beabstandeten Sensoreinrichtungen der in 1a auf einem Kreisbogen;
• 4 den Verlauf der an den beiden Sensoreinrichtungen erfassten unterschiedlichen Feldkomponenten über eine Volldrehung des Magneten um die Drehachse;
• 5 den Verlauf der an den beiden Sensoreinrichtungen erfassten Verläufe der anderen unterschiedlichen Feldkomponenten über eine Volldrehung der Magneteinrichtung um die Drehachse;
• 6 den Verlauf der kombinierten Sensorsignale der 4 und 5 über eine Volldrehung des Magneten um die Drehachse;
• 7 den Verlauf des Winkelfehlers über eine Volldrehung für den nach dem erfindungsgemäßen Verfahren berechneten Drehwinkel im Vergleich zu dem Winkelfehler, der sich nach dem herkömmlichen Verfahren ergibt;
• 8 den Verlauf der erfindungsgemäß kombinierten Signale zur Berechnung des Drehwinkels für eine weitere Ausführungsform mit zur erst beschriebenen Ausführungsform unterschiedlichen axialen und radialen Beabstandung der Sensoreinrichtungen zum Magneten;
• 9 die örtliche Anordnung der Sensoreinrichtungen in einer erfindungsgemäßen Drehwinkelgebereinrichtung zur Kompensation eines Fremdfeldes; und
• 10 den Verlauf des Winkelfehlers bei der Anordnung der Sensoreinrichtungen gemäß 9 beim Auftreten eines Fremdfeldes, das betragsmäßig in dergleichen Größenordnung wie das Nutz- bzw. Messfeld des Magneten ist,

zeigt.The invention is explained below with reference to the accompanying drawing figures by describing some embodiments, where

• 1a in a reduced schematic diagram of a rotary angle encoder device according to the invention with an annular, axially polarized, 4-pole sintered ferrite magnet with a sensor arrangement arranged on the front side of the magnet and axially spaced apart in a front view;
• 1b the rotary angle sensor device 1a in a radial view;
• 2 the course of the sensor arrangement according to a sensor device 1a detected tangential and axial field components when the magnet rotates about the axis of rotation A relative to the stationary sensor arrangement;
• 3 the arrangement of the two circumferentially spaced sensor devices in 1a on a circular arc;
• 4 the course of the different field components detected at the two sensor devices over a full rotation of the magnet around the axis of rotation;
• 5 the course of the courses of the other different field components detected at the two sensor devices over a full rotation of the magnet device about the axis of rotation;
• 6 the course of the combined sensor signals 4 and 5 via a full rotation of the magnet around the axis of rotation;
• 7 the course of the angular error over a full rotation for the angle of rotation calculated using the method according to the invention in comparison to the angular error resulting from the conventional method;
• 8th the course of the signals combined according to the invention for calculating the angle of rotation for a further embodiment with a different axial and radial spacing of the sensor devices from the magnet than the first described embodiment;
• 9 the local arrangement of the sensor devices in a rotary angle sensor device according to the invention for compensating for an external field; and
• 10 the course of the angular error in the arrangement of the sensor devices 9 when an external field occurs that is of the same magnitude as the useful or measuring field of the magnet,

shows.

1a shows a reduced schematic diagram of a rotary angle encoder device 1 according to the invention with an annular, axially polarized, 4-pole sintered ferrite magnet 10 with a sensor arrangement 3 arranged on the end face of the magnet 10 and axially spaced apart in an end view. Due to the polarization described and the view of the magnet 10 on its upper end face, it has the opposite polarization on its opposite, ie lower end face. In the described embodiment of the rotary angle sensor device 1, the magnet 10 is arranged to be rotatable during operation about the axis of rotation A, which here also represents an axis of symmetry of the magnet 10. The magnet 10 can be firmly connected to an actuating shaft, not shown, which is oriented coaxially to the axis of rotation A.

In the embodiment described first, the sensor arrangement 3 for detecting the field components, here a tangential and an axial field component, is arranged stationary in a plane E parallel to the end face of the magnet 10. The information tangential or axial refers to directions with reference to the specified axis of rotation A.

In the embodiment of the rotary angle sensor device 1 designed according to the invention 1a The sensor arrangement 3 comprises two sensor devices 30a, 30b in the form of Hall sensors, offset circumferentially by an angle of β = 45° relative to the axis of rotation A, each sensor device 30a, 30b for detecting the axial field component and tangential field component present at the respective sensor location and for output a relevant sensor signal is formed. For this purpose, in the described embodiment, each of the sensor devices 30a, 30b has two sensors 31a, 32a or 31b, 32b for separately detecting or measuring the two field components at the location of the respective sensor device 30a, b. In another embodiment, it can be provided that each of the sensor devices has a 2D or 3D Hall sensor, with which the two field components are detected at the location of the respective sensor 31a, 31b, 32a, 32b or the respective sensor device 30a, 30b.

In the described embodiment, the movement path of the sensor arrangement 3 is relative to that in the 1a specified end face of the magnet 10 is offset by an axial distance of 2 mm, while the inner diameter of the magnet 10 is 16 mm, the outer diameter is 32 mm and the axial length is 5 mm. How out 1a As can be seen, the sensor devices 30a, b are arranged radially within the physical extent, in particular approximately in the radial center of the magnet 10, ie centrally between the inside and outside diameter of the magnet 10.

1b shows in a radial side view of the rotary encoder device 1 according to the invention the magnet 10 of the 1a together with the sensor plane E, in which the two sensor devices 30a, b are arranged, spaced circumferentially by 45°, wherein the axial distance aA of the sensor plane E to the nearest end face of the ring-shaped magnet 10 and the radial distance rA of the sensor devices 30a, b relative to the axis of rotation A or to the axis of symmetry A of the magnet 10 are also indicated. In the 1b the radial distance rA is specified for the sensor device 30 a, since in the illustration shown the radius vector from the axis A to the sensor device 30 a lies in the plane of the drawing. As described, the sensor devices 30 a, b are arranged in the plane E on a circular arc, with the axis A running through the center of the circular arc. Accordingly, the radial distance of the sensor devices 30 b to the axis A is also rA.

The field components that can be detected with a stationary sensor device 30a, b when the magnet 10 rotates about the axis of rotation A, here a tangential field component and an axial field component, run periodically, but not in a purely sinusoidal or cosinusoidal manner, so that a simple determination of the Angle of rotation by applying an arctan function to the quotient of the sinusoidal course of one field component by the cosinusoidal course of the other field component at the location of one of the respective sensor devices leads to a determination of the angle of rotation which is very error-prone and, depending on the angle of rotation, easily results in an error of +- 15 ° can have.

2 shows for the sensor device 30a the course Ka1 of the axial field component measured by means of the sensor 31a and the course Kt1 of the tangential field component measured by means of the sensor 32a as a function of the angle of rotation of the magnet 10 over a full rotation of 360 °. It can be seen that the two curves are phase-shifted by 45° due to the described 4-pole nature of the magnet 10, whereby the curves are periodic, but not purely sinusoidal or cosinusoidal. Calculating the angle of rotation by quotienting both curves and applying an arctan function to the result leads to a highly error-prone result that is unusable for most applications. The person skilled in the art will recognize that the curves of the sensor device 30b are in the same way, but out of phase, with respect to the detected field components.

In order to improve the recorded field profiles, the invention proposes to provide a sensor arrangement 3 comprising two circumferentially spaced sensor devices 30a, b, which each detect the two different field components at their respective locations in the form of measurement signals and generate combination signals by combining these signals. The measurement signals are combined in such a way that components of higher harmonics compensate for each other and the combination signals then represent “improved” sine or cosine curves, on the basis of which a respective angle of rotation can be determined, in particular as part of a calculation, which is a much smaller one Has angle errors compared to a conventional rotary angle sensor device 1 or a conventional method.

und $${\text{U}}_{\text{cos}}=\text{Sa}2-\text{St}\mathrm{1,}$$

By using two different sensor devices 30a, b spaced circumferentially by 45° in the described embodiment 1a , b results in a uniform phase position for the individual combination signals, in which the combination signals can be determined as follows: $${\text{U}}_{\text{sin}}=\text{<figure-callout id="1" label="Sat" filenames="DE102022124958A1\_0012.png" state="{{state}}">Sat</figure-callout>}1+\text{St}2$$

and $${\text{U}}_{\text{cos}}=\text{Sat}2-\text{St}\mathrm{1,}$$

The expression U _sin according to Eq. 1a shows a sinusoidal curve of a sum signal from two summands, where the first summand Sa1 is a measurement signal or a measured value from the first sensor device 30a to indicate the axial field component and the second summand St2 is the measurement signal or the measured value from the second sensor device 30b to indicate the tangential represents field component. Furthermore, the expression U _cos according to equation 1b represents a cosine-like curve of a difference signal, whereby the minuend signal Sa2 is a measurement signal or a measured value from the second sensor device 30b for indicating the axial field component and the subtrahend signal St1 is a measurement signal or a measured value from the first sensor device 30a Specification of the tangential field component. Simultaneously with the reduction of the proportions of higher harmonics, equations 1a, 1b result in the amplitudes being equalized to a common value.

wobei c den gesuchten Drehwinkel darstellt und α0 ein beliebiger Startwinkel bei der Drehung des Magneten 10 um die Achse A. 3 shows the course of the combined signals U _sin , U _cos , where the curve KS1 of the equation Eq. 1a and the curve KS2 of the equation Eq. 1b corresponds. It can be seen that the combined signal curves KS1, KS2 have an improved sine or cosine-like curve, so that a subsequent determination of the angle of rotation in a signal processing device, not shown in the figures, which records and processes the signals detected by the sensor devices 30a, 30b, by simply using a Arctan function on the quotient of the curves can be determined with an error that is acceptable for most applications, ie with the equation $$\mathrm{\alpha }=2/\text{np}*\text{arctan}\left(\text{Usin}/\text{Ucos}\right)+\mathrm{\alpha }\mathrm{0,}$$

where c represents the desired angle of rotation and α0 any starting angle when rotating the magnet 10 about the axis A.

4 shows the course of the angular error in degrees over a full rotation of the magnet 10 about the axis of rotation A through the curve marked with the reference symbol E1. Curve E2 represents the angular error in the calculation according to Eq. 2 based on the measured and therefore uncombined field components of the 2 It can be seen that the angle error varies by up to 17° when carrying out a conventional determination method of the rotation angle, while the angle error varies when carrying out the method according to the invention with a rotary angle sensor device 1 designed according to the invention according to 1a , 1b the angular error varies by the maximum values +- 3.1° and thus leads to a significantly reduced angular error. It should be noted that curve E1 has a doubling of frequency and therefore zeros compared to curve E2, since each edge now has a change from convex to concave deviation from the sine or cosine, respectively, resulting in a doubled deviation from the linearity of the particular Field angle is given. In contrast, with conventional evaluation, the deviation per edge is only purely convex or concave.

In the with reference to the 1a and 1b In the described embodiment of a rotary angle encoder device 1 according to the invention, the axial sensor distance aA to the nearest end face of the axially magnetized, uniaxial-anisotropic permanent magnet is comparatively small in relation to its dimensions and due to the comparatively small number of poles np with aA = 2 mm. If the axial distance aA of the sensor arrangement 3 or the sensor devices 30a, 30b to the magnet 10 is increased slightly, “softer” curves of the various field components result, which is advantageous for achieving the lowest possible angular errors. For this purpose, it can expediently be provided that the axial distance aA of the sensor arrangement 3 to the nearest end face of the ring or cylinder magnet is at least 50%, in particular at least 60%, preferably more than 2/3 of the axial length of the magnet 10.

In other embodiments, the magnet arrangement may, for example, not include a sintered magnet, but rather a plastic-bonded magnet, in particular an isotropic, low-pole plastic-bound magnet, which can generally provide a more sinusiodal field profile compared to sintered magnets. 5 shows the curves of the equations according to the above equations. 1a, Eq. 1b determined combined signals KS1, KS2 for a rotary angle sensor device 1, which are identical to those in the 1a , 1b shown is designed with the exception of the fact that the magnet 10 is a plastic-bound magnet which has four poles and is polarized in the axial direction, the distance between the plane of the sensor arrangement 3 and the nearest end face of the magnet being 3.5 mm. 6 again shows the angular error curve E1 similar to that 4 for the one according to Eq. 2 specific rotation angles over a full revolution of the magnet 10 compared to the course E2, which refers to an axial distance of the sensor arrangement 3 to the nearest end face of the magnet 10 of 1.5 mm. It can also be seen here that the angular error can be significantly reduced by the method according to the invention; in the example described, the angular error is limited to a maximum of +-1.4°. Regarding the different number of zeros in the course of curves E1 and E2, please refer to the relevant explanation 4 referred.

The examples show that with the method according to the invention for detecting a relative rotation angle position and with a rotation angle transmitter device 1 according to the invention, a rotation angle determination of usable quality is also possible for field transmitter magnets that are unsuitable for a conventional determination of the field angle. This applies both to uni-axially anisotropic magnets such as sintered magnets and to isotropic magnets such as plastic-bonded magnets with a magnetization that deviates more from a sinusoidal shape.

The method according to the invention or the rotary angle sensor device 1 according to the invention is not limited to the use of 4-pole magnets and a resulting angular distance between the two sensor devices 30a, 30b of 45°. Instead, the method according to the invention or the rotary angle transmitter device 1 according to the invention can also be used for the use of magnets with a higher even number of poles, with the angular distance between the two sensor devices 30a, 30b then resulting in π/np, where np in turn indicates the number of poles.

und $${\text{U}}_{\text{cos}}=\text{Sr}2-\text{St}1$$

In a further embodiment, it can also be provided that the magnet arrangement or a magnet of the magnet arrangement is magnetized on the circumference, so that the sensor devices 30a, 30b can then be arranged at a position that is radially spaced from the lateral surface of the cylinder or ring magnet. Instead of the tangential and axial field components, in this embodiment the tangential and radial field components can be detected by the two sensor devices 30a, 30b or their sensors 31a, 32a and used in the same way as above for the first described embodiment to determine the angle of rotation. Analogous to Eqs. 1a, 1b the combined sine and cosine signals are calculated using the expressions $${\text{U}}_{\text{sin}}=\text{<figure-callout id="1" label="Sr" filenames="DE102022124958A1\_0012.png" state="{{state}}">Sr</figure-callout>}1+\text{St}2$$

and $${\text{U}}_{\text{cos}}=\text{Sr}2-\text{<figure-callout id="1" label="St" filenames="DE102022124958A1\_0012.png" state="{{state}}">St</figure-callout>}1$$

The expression U _sin according to Eq. 3a shows a sinusoidal curve of a sum signal from two summands, whereby the first summand Sr1 is a measurement signal or a measured value of the first sensor device 30a for outputting the radial field component and the second summand St2 is the measurement signal or the measured value of the second sensor device 30b for indicating the tangential represents field component. Similarly, the expression U represents _cos according to Eq. 3b represents a cosine-shaped curve of a difference signal, whereby the minuend signal Sr2 represents a measurement signal or a measured value of the second sensor device for outputting the radial field component and the subtrahend St1 represents the measurement signal or the measured value of the first sensor device 30a for outputting the tangential field component.

Suitable magnets that are used for this third embodiment of the invention can, for example, be radially anisotopic sintered magnets or rings made of sintered magnets that are composed of individual pole segments with homogeneous or radial magnetization. In addition, magnets made of isotropic, sintered or plastic-bonded magnetic material, the field shape of which differs significantly from a sinusoidal shape, can also be used as field transmitters together with the method according to the invention or in the rotary angle transmitter device 1 designed according to the invention without further data processing for determining the angle of rotation with high accuracy.

In one embodiment of the invention, this can be used not only to reduce the error in the simple determination of a rotation angle, but also to simultaneously compensate for external fields, which often occur in practice and then represent an additional source of error. A solution to this problem can be to provide soft magnetic shielding, although this can be associated with considerable costs depending on the application. In contrast, instead of providing two sensor devices 30a, 30b spaced circumferentially from the axis of rotation A, the invention proposes the provision of a sensor array with four sensor devices 30a, 30b, 30c, 30d, whereby to compensate for an external field influence on the measurements of each sensor device 30a, 30b, 30c, 30d one of the three other sensor devices 30a, 30b, 30c, 30d is assigned, to which it is spaced radially with respect to the axis of rotation A, see 7 . The representation of the 7 can refer to the embodiment of the 1a , 1b relate and be structurally identical with the only difference being that in addition to the extensive two further sensor devices 30c 30d are included on a circular arc of 45 °, spaced apart sensor devices 30a, 30b. The sensor device 30c can be assigned to the sensor device 30a and placed relative to it with the same center angle, but at a radial distance on the plane E of the sensor arrangement 3. The same applies to the mutually assigned sensor devices 30b and 30d, which in turn can be arranged on the same radial vector, but at a radial distance from one another, the radial spacing for the two pairs of sensor devices 30a, 30c and 30b, 30d can be identical.

Each of the sensor devices 30a to 30d of the embodiment according to 7 comprises a sensor for detecting a tangential field component and a sensor for detecting an axial sensor component. In 7 Instead of the individual sensors 31a, 31b, 32a, 32b, the signals emitted by these are Sa _ij and St _ij , i = 1,2 and j = 1,2, where Sa _ij is a respective measurement signal of the axial field component and the signal St _ij is the signal of a corresponding sensor for detecting the tangential field component.

The person skilled in the art recognizes that when using the method according to the invention with simultaneous compensation of external fields, the circumferential spacing of the two pairs of sensor devices 30a, 30c and 30b, 30d on a circular arc depends on the number of poles of the magnet 10 and, as stated above, via the relationship π/ np can be set.

$$\mathrm{\Delta }\text{U}\_\text{a}2=\text{Sa}22-\text{Sa}21$$

$$\mathrm{\Delta }\text{U}\_\text{t}1=\text{St}12-\text{St}11$$

$$\mathrm{\Delta }\text{U}\_\text{t}2=\text{St2}2-\text{St}21$$

In the modified method with external field compensation, a difference is first formed between the detected signals of the described pairs of sensor devices 30a, 30c and 30b, 30d for the respective field components $$\mathrm{\Delta }\text{U}\_\text{a}1=\text{Sat}12+\text{Sat}11$$

$$\mathrm{\Delta }\text{U}\_\text{a}2=\text{Sat}22-\text{Sat}21$$

$$\mathrm{\Delta }\text{U}\_\text{<figure-callout id="1" label="t" filenames="DE102022124958A1\_0012.png" state="{{state}}">t</figure-callout>}1=\text{St}12-\text{St}11$$

$$\mathrm{\Delta }\text{U}\_\text{t}2=\text{St2}2-\text{St}21$$

It should be noted that in another embodiment, so-called gradient sensors can also be used directly, which can internally carry out the described subtraction of the signals from assigned sensors 31a, 31, b, 32a, 32b for the same field component, so that they are the ones in the equations Output the difference signals specified in 4a to 4d directly.

$${\text{U}}_{\text{cos}}=\mathrm{\Delta }\text{U}\_\text{a}2-\mathrm{\Delta }\text{U}\_\text{t}1$$

wobei wiederum U_sin das sinusartige Kombinationssignal und U_cos das cosinusartige Kombinationssignal bezeichnet, so dass in der beschriebenen Ausführungsform der Drehwinkel entsprechend der obenstehend angegebenen Gleichung 2 berechnet werden kann.In the with reference to 7 The embodiment described takes place in the next step with reference to 1a , 1b described combination of signals, ie $${\text{U}}_{\text{sin}}=\mathrm{\Delta }\text{U}\_\text{a}1+\mathrm{\Delta }\text{U}\_\text{t}2$$

$${\text{U}}_{\text{cos}}=\mathrm{\Delta }\text{U}\_\text{a}2-\mathrm{\Delta }\text{U}\_\text{<figure-callout id="1" label="t" filenames="DE102022124958A1\_0012.png" state="{{state}}">t</figure-callout>}1$$

where again U _sin denotes the sine-like combination signal and U _cos denotes the cosine-like combination signal, so that in the described embodiment the angle of rotation can be calculated according to equation 2 given above.

It has fundamentally been found that in the method according to the invention described for detecting an angle of rotation position with simultaneous external field compensation, the array of sensor devices 30a to 30d should not preferably be arranged in the area of the central radius of the ring magnet, as is the case with axially magnetized magnets, but rather the array of sensor devices 30a to 30d radially at radii larger than the average radius between the inner and outer radius, or even radially outside the magnet 10 to use strong gradients of the field components.

The method according to the invention described with simultaneous external field compensation is particularly suitable in cases in which the magnet 10 of the magnet arrangement is a plastic-bound magnet, which generally has lower field strengths than a sintered magnet and therefore has a greater sensitivity to external fields. With the methods described, it is possible, for example, when using a 4-pole ring magnet with rigid magnetization, an inner diameter of 16 mm, an outer diameter of 30 mm and an axial height of 5 mm, despite the occurrence of an external field that is half the field strength of the magnet 10 has to realize a substantially complete external field compensation, at the same time limiting the angular error to +- 3° via a full rotation of the magnet 10.

In a further embodiment, it can also be provided to carry out the method with external field compensation or a correspondingly designed rotary angle sensor device 1 with magnets 10 which are magnetized on the circumference, so that the sensor devices 30a to 30d are then at a position spaced radially from the lateral surface of the magnet 10 and instead of the tangential and axial field components, the tangential and radial field components are recorded and the angle of rotation is determined on this basis.

Reference symbol list

1

Rotary angle sensor device, rotary angle sensor

3

Sensor arrangement

10

magnet

30a

Sensor device

30b

Sensor device

30c

Sensor device

30d

Sensor device

31a

sensor

31b

sensor

32a

sensor

32b

sensor

A

Axis of rotation

aa

axial distance

b

Sensor path

E

Sensor level

rA

radial distance

QUOTES INCLUDED IN THE DESCRIPTION

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

Cited patent literature

• DE 10201820665 A1 [0002]
• DE 102018220665 A1 [0002]

Claims (16)

Method for detecting a relative rotation angle position between a sensor arrangement (3) and a magnet arrangement of a rotation angle sensor device (1), wherein the sensor arrangement (3) and the magnet arrangement are arranged to be rotatable relative to one another about an axis of rotation (A), and the magnet arrangement comprises a multipolar, field-generating permanent magnet and the sensor arrangement (3) is designed to detect at least two different field components in the form of assigned measurement signals, with the sensor arrangement (3) producing a respective periodic, in particular sine or cosine-like course of the field components over the relative rotational movement of the sensor and magnet arrangement associated measurement signals is detected, and a rotation angle indicating the relative rotation angle position is determined on the basis of the detected different field components, characterized in that at least two sensor devices (30a, 30b, 30c, 30d) of the sensor arrangement (3) are arranged circumferentially spaced apart, and from each sensor device (30a, 30b, 30c, 30d) signals are determined which depend on the different field components present locally, at least one sum signal and a difference signal of these signals being determined to compensate for signal components of higher harmonics in the course of the field components during the rotational movement, and the angle of rotation is determined depending on the sum signal and the difference signal. Procedure according to Claim 1 , characterized in that the sum signal is formed from two summands, the first summand being a signal from a first of the at least two sensor devices (30a, 30b) assigned to a first of the two magnetic field components and the second summand being a signal assigned to a second of the two magnetic field components Signal from a second of the at least two sensor devices (30a, 30b). Procedure according to Claim 1 or 2 , characterized in that the difference signal is formed by subtracting a subtrahend signal from a minute end signal, one of the latter two signals (subtrahend signal, minute end signal) being a signal assigned to the first of the two magnetic field components from the second of the at least two sensor devices (30a, 30b) and the other of the latter two signals (subtrahend signal, minute end signal) is a signal from the first of the at least two sensor devices (30a, 30b) assigned to the second of the two magnetic field components. Procedure according to Claim 1 , 2 or 3 , characterized in that when determining the angle of rotation, an arctan function is applied to a quotient, in which the dividend is formed by the sum signal and the divisor is formed by the difference signal. Procedure according to Claim 4 , characterized in that when determining the angle of rotation, the result of applying the arctan function to the quotient is multiplied by the quotient (2/np), where np indicates the number of poles of the magnet (10) of the magnet arrangement. Procedure according to one of the Claims 1 until 5 , characterized in that the two sensor devices (30a, 30b) of the sensor arrangement (3) are arranged circumferentially spaced apart by a center angle β of β = π/np on a circular arc, where np indicates the number of poles of the magnet arrangement. Procedure according to one of the Claims 1 until 6 , characterized in that a tangential and an axial field component or a tangential and a radial field component are detected as different field components of the permanent magnet. Procedure according to one of the Claims 1 until 7 , characterized in that the magnet arrangement is arranged to be rotatable about the axis of rotation (A) relative to the stationary sensor arrangement (3), or that the sensor arrangement is arranged to be rotatable about the axis of rotation (A) to the stationary magnet arrangement (3). Procedure according to one of the Claims 1 until 8th , characterized in that the sensor devices (30a, 30b) of the sensor arrangement (3) for providing external field compensation are each designed as a gradient sensor device, each comprising two radially spaced sensors (31a, 31b; 32a, 32b) for each field component, via which the respective Measurement signals assigned to field components are recorded. Procedure according to Claim 9 , characterized in that with the measurement signals of the respective gradient sensor device assigned to the same field component, a respective external field-compensated signal is generated by subtraction, so that with the external field-compensated signals a signal assigned to the first field component and a signal assigned to the second field component are provided by each gradient sensor device for determination the sum signal and the difference signal. Rotary angle sensor device (1) for detecting a relative rotation angle position, comprising a sensor arrangement (3) and a magnet arrangement, which are arranged to be rotatable relative to one another about an axis of rotation (A), the magnet arrangement comprising a multipolar, field-emitting permanent magnet (10) and the sensor arrangement (3) for Detection of different field components is designed in the form of assigned measurement signals, and a respective periodic, in particular sine or cosine-like course of the field components can be detected via the assigned measurement signals by the sensor arrangement (3) during a relative rotational movement of the sensor and magnet arrangement, and by means of a Signal processing device can determine a rotation angle (α) indicating the relative rotation angle position on the basis of the detected different field components, characterized in that at least two sensor devices (30a to 30d) of the sensor arrangement (3) are arranged circumferentially spaced apart, and each sensor device (30a to 30d) the locally present different field components are detected via assigned signals, with at least one sum signal and a difference signal of these signals being determined for the respective compensation of signal components of higher harmonics in the course of the signals during the relative rotational movement, and the signal processing device is designed and set up to depend on the angle of rotation of the sum signal and the difference signal. Rotary angle sensor device (1). Claim 11 , characterized in that the sensor devices (30a to 30d) of the sensor arrangement (3) are arranged circumferentially spaced apart by a center angle β of β = π/Np on a circular arc, where np indicates the number of poles of the magnet (10) of the magnet arrangement. Rotary angle sensor device (1). Claim 11 or 12 , characterized in that the magnet arrangement has an axially or radially magnetized, multipolar, in particular 4-pole, 6-pole or 8-pole permanent magnet. Rotary angle sensor device (1). Claim 11 , 12 or 13 , characterized in that the magnet arrangement is arranged to be rotatable about the axis of rotation (A) to a stationary carrier which carries the sensor arrangement (3), or that the sensor arrangement (3) is arranged on a support and the carrier is arranged around the axis of rotation (A ) is arranged rotatably relative to the stationary magnet arrangement. Rotary angle sensor device (1) according to one of the Claims 11 until 14 , characterized in that the sensor arrangement (3) is arranged axially spaced from and radially within the magnet arrangement, or the sensor arrangement (3) is arranged radially spaced from and axially within the magnet arrangement. Rotary angle sensor device (1) according to one of the Claims 11 until 15 , characterized in that the sensor devices (30a to 30d) of the sensor arrangement (3) are each designed as a gradient sensor device.

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