METHOD FOR CONTROLLING A PLANAR DRIVE SYSTEM AND PLANAR DRIVE SYSTEM

A method for controlling a planar drive system includes identifying a preferred stator module direction with a preferred magnetic field or sensor direction, and identifying a preferred mover direction with a respective other of the preferred magnetic field or sensor direction; setting a magnetic orientation field with a magnet device; recording at least a measurement value of the magnetic orientation field with a magnetic field sensor device; determining an alignment of the preferred mover direction relative to the preferred stator module direction based on the measurement value of the component of the magnetic orientation field parallel to the preferred sensor direction; and determining a first orientation of the mover on the stator module, on the basis of the alignment of the preferred mover direction relative to the preferred stator module direction. The application also relates to a planar drive system.

FIELD

The present application relates to a method for controlling a planar drive system, and to a planar drive system arranged to perform the method of controlling a planar drive system.

BACKGROUND

Planar drive systems may be used, among other things, in automation technology, in particular manufacturing technology, handling technology and process engineering. Planar drive systems may be used to move or position a moving element of a plant or machine in at least two linearly independent directions. Planar drive systems may comprise a permanently energized electromagnetic planar motor with a planar stator and a mover movable on the stator in at least two directions.

In a permanently energized electromagnetic planar motor, a driving force is exerted on the mover by current-carrying conductors magnetically interacting with driving magnets of a magnet assembly. The application particularly relates to embodiments of planar drive systems in which the drive magnets of an electric planar motor are arranged on the mover and the current-carrying conductors of the planar motor are arranged in a stationary planar stator.

In such a drive system, the mover comprises at least a first magnetic unit for driving the mover in a first direction and a second magnetic unit for driving the mover in a second direction linearly independent of the first direction, e.g. in a direction orthogonal to the first direction. The planar stator comprises at least a group of first energizable conductors magnetically interacting with the magnets of the first magnet unit to drive the mover in the first direction, and a group of second energizable conductors magnetically interacting with the magnets of the second magnet unit to drive the mover in the second direction. The first and second groups of conductors are generally independently energizable to allow independent movement of the mover in the first and second directions. If the conductors of the first and second groups themselves may be energized independently of one another at least in parts, a plurality of movers may be moved independently of each other on one stator at the same time.

To control a mover of a planar drive system, it is essential to be able to determine a position of the mover relative to the stator module or stator modules of the planar drive system. For this purpose, each stator module has at least one sensor module with a plurality of magnetic field sensors that are set up to detect the magnetic field of the mover, which makes it possible to determine the position of the mover relative to the respective sensor module or relative to the respective stator module. The more precisely such a determination of a position of the mover may be carried out, the more precisely a control of the planar drive system may be performed.

In addition to a position determination, which primarily detects a translational movement of the mover, it is advantageous to determine an orientation of the mover relative to the stator module to achieve a precise control of the mover. A determination of the orientation primarily detects a rotation of the mover around a rotational axis oriented perpendicularly to a stator surface of the stator module and running through a geometric center of the mover.

Determining the orientation of the mover relative to the stator module is of particular interest if a preferred orientation of the mover exists due to the respective application of the planar drive system, e.g. because the workpieces to be transported by the stator are to be transported with a preferred orientation.

Furthermore, determining the orientation of the mover relative to the stator module allows for an improved precision of the position determination of the mover on the stator module. Particularly in the case in which a position is determined based on an exact knowledge of the magnetic mover field of each individual mover, an exact determination of the orientation of the mover relative to the stator module may be advantageous. By knowing the exact orientation of the mover relative to the stator module, values of the magnetic mover field recorded by the magnetic field sensors for determining the position of the mover may be better interpreted, resulting in improved precision of the position determination.

Determining an orientation of the mover relative to the stator module is particularly challenging when, as in the case of the present application, the mover, and in particular the magnet assembly of the mover, is rotationally symmetrical with respect to the axis of rotation oriented perpendicular to the stator surface of the stator module. According to the application, the mover, and in particular the magnet assembly of the mover and the magnetic mover field generated thereby, is rotationally symmetrical with respect to a rotation about the axis of rotation oriented perpendicular to the stator surface by 90°, 180° and 270°, so that the mover and the magnetic mover field may be transduced into each other by a rotation by 90°, 180° or 270° and obviously 0° and 360°. Based on the embodiment of the mover, the magnet assembly and the magnetic mover field generated thereby, an orientation of 90°, 180°, or 270° is indistinguishable from an orientation of 0°.

SUMMARY

The present application provides a method for controlling a planar drive system, which allows for improved and more precise control of a mover due to improved orientation determination of the mover. The application further provides a planar drive system which is arranged to carry out the method according to the application.

EXAMPLES

A method of controlling a planar drive system is provided, the planar drive system comprising at least a controller, a stator module having a stator surface, and a mover that may be positioned on the stator surface. The stator module is arranged to generate magnetic fields for electrically controlling the mover along the stator surface, the mover having a magnet assembly for generating a magnetic mover field, wherein a magnetic coupling between the mover and the stator module is achievable via the magnetic stator fields and the magnetic mover field, wherein the stator module comprises a sensor module having a plurality of magnetic field sensors for determining a position of the mover, wherein the stator module or the mover comprises a magnet device for generating an magnetic orientation field, wherein the magnetic orientation field is rotationally asymmetrical with respect to rotation about a rotational axis perpendicular to the stator surface and has a preferred magnetic field direction, and wherein the respective other of the stator module and the mover comprises a magnetic field sensor device having a preferred sensor direction for detecting the magnetic orientation field along the preferred sensor direction.

The method comprises:identifying a preferred stator module direction of the stator module with one of the preferred magnetic field direction or the preferred sensor direction, and identifying a preferred mover direction of the mover with the respective other of the preferred magnetic field direction and the preferred sensor direction in a preferred direction identifying step, wherein the preferred stator module direction is oriented in parallel to the stator surface of the stator module, and wherein the preferred mover direction is oriented in parallel to a running surface of the mover;providing the magnetic orientation field by the magnet device in a magnetic field setting step;taking at least a measurement value of the magnetic orientation field by the magnetic field sensor device in a magnetic field determining step, the at least one measurement value of the magnetic orientation field comprising at least one value of a component of the magnetic orientation field in a direction parallel to the preferred sensor direction;determining an alignment of the preferred mover direction relative to the preferred stator module direction based on the measurement value of the component of the magnetic orientation field in parallel to the preferred sensor direction in an alignment determining step;determining a first orientation of the mover on the stator module on the basis of the alignment of the preferred mover direction relative to the preferred stator module direction in an orientation determining step, wherein a first orientation of the mover relative to the stator module is transferable to a second orientation of the mover relative to the stator module via a rotation of the mover relative to the stator module about the axis of rotation oriented perpendicularly with regard to the stator surface and extending through a geometric center of the mover.

This provides the technical advantage of providing a method for controlling a planar drive system suitable for determining an orientation of a mover of the planar drive system relative to a stator module of the planar drive system.

DETAILED DESCRIPTION

For purposes of the application, an orientation of the mover relative to the stator module is provided via an alignment of a preferred mover direction relative to a preferred stator module direction. A first orientation of the mover relative to the stator module may be converted into a second orientation of the mover relative to the stator module via a rotation of the mover about a rotational axis extending perpendicularly with regard to a stator surface of the stator module and passing through a geometric center of the mover.

An alignment of the preferred mover direction relative to the preferred stator module direction may e.g. be expressed by an angle between the preferred mover direction and the preferred stator module direction.

For the purposes of the application, a preferred mover direction is a direction of the mover which may be selected as desired and by which a rotation of the mover about the rotational axis may be determined by a corresponding re-alignment of the defined preferred mover direction. The preferred mover direction is arbitrarily selectable and serves exclusively for the distinguishability of different orientations of the mover relative to the stator module, in particular if the mover is embodied with a rotationally symmetrical shape. However, the preferred mover direction is independent of the embodiment of the mover and may be freely selected independently of it.

For the purposes of the application, a preferred stator module direction is in this context a direction parallel to the stator surface of the stator module that may be selected as required, via which an alignment of the preferred mover direction and thus an orientation of the mover relative to the stator module may be defined.

For determining an orientation of a mover relative to the stator module of the planar drive system, the planar drive system comprises a magnetic device for generating a magnetic orientation field and a magnetic field sensor device for detecting the magnetic orientation field. The magnetic orientation field is rotationally asymmetric with respect to the axis of rotation oriented perpendicularly to the stator surface and comprises a preferential magnetic field direction. The magnetic field sensor device has a preferred magnetic field sensor direction and is set up to detect components of the magnetic orientation field parallel or antiparallel to the preferred sensor direction.

In order to determine the orientation of the mover relative to the stator module, the magnetic field device is either embodied on the mover or on the stator module. The magnetic field sensor device is embodied on the respective other component of the planar drive system, i.e. either on the stator module or the mover.

By identifying the preferred sensor direction with the preferred mover direction or the preferred stator module direction, depending on whether the magnetic field sensor device is embodied at the mover or at the stator module, and after identifying the preferred magnetic field direction with the preferred mover direction or the preferred stator module direction, depending on whether the magnetic field device is embodied at the mover or at the stator module, an alignment of the preferred sensor direction relative to the preferred magnetic field direction and, associated therewith, an alignment of the corresponding preferred mover direction relative to the preferred stator module direction may be determined by the magnetic field sensor device by recording measurement values of a component of the magnetic orientation field parallel or antiparallel to the preferred sensor direction. On the basis of the determined alignment of the preferred mover direction relative to the preferred stator module direction, an orientation of the mover relative to the stator module may be determined.

This has the particular advantage that, in the case of a rotationally symmetrically embodied mover, which may be transduced in itself in particular by rotations around 90°, 180° or 270°, an orientation relative to the stator module, which comprises a corresponding rotation by 90°, 180° or 270°, may be determined. This makes it possible to unambiguously determine the orientation of the mover relative to the stator module, thereby allowing for effective control of the mover.

According to an embodiment, the method further comprises:determining a position of the mover relative to the stator module by taking a plurality of measurement values of the magnetic mover field of the mover by magnetic field sensors of the sensor module of the stator module in a position determining step, wherein a first position of the mover relative to the stator module may be transduced into a second position of the mover relative to the stator module via a translation of the geometric center of the mover relative to the stator module in a translation direction running perpendicularly with regard to the rotational axis.

This provides the technical advantage of providing effective control of the planar drive system. Determining the position of the mover on the stator module allows for a direct control of the mover by corresponding stator conductors of the stator module. Furthermore, determining a position allows for selecting those magnetic field sensors of the sensor module of the stator module, which are positioned in the direct vicinity of the mover and are thus required for a further control and further position determinations of the mover.

According to an embodiment, the method further comprises:providing a magnetic locking field by the stator module for locking the mover in position in a locking step, wherein the magnetic locking field is oppositely aligned to the magnetic mover field in such a way that an attractive magnetic coupling is generated between the magnetic locking field and the magnetic mover field.

This achieves the technical advantage that a precise determination of the orientation of the mover relative to the stator module may be achieved. By locking the mover in the determined position relative to the stator module, further movement of the mover relative to the stator module during the determination of the orientation is prevented. This provides a more precise orientation determination of the mover relative to the stator module. In addition, magnetic coupling between the magnetic orientation field required for orientation determination with either the magnetic mover field of the mover or the magnetic stator field of the stator module, which would result in movement of the mover relative to the stator module, may be prevented.

According to an embodiment, the method further comprises:orienting the mover from the first orientation to a second orientation based on the alignment of the preferred mover direction relative to the preferred stator module direction in an orientation step.

This provides the technical advantage of providing precise control of the planar drive system. After determining the orientation of the mover relative to the stator module, a change in the orientation of the mover relative to the stator module may be achieved. In particular, for applications in which a specific orientation of the mover relative to the stator module, e.g. due to a predetermined orientation of the workpieces to be transported by the mover, a change in the orientation of the mover relative to the stator module is advantageous. This provides precise and widely applicable control of the planar drive system.

According to an embodiment, the magnet device is embodied at the stator module and the magnetic field sensor device is embodied at the mover, wherein the preferred stator module direction is identified with the preferred magnetic field direction and the preferred mover direction is identified with the preferred sensor direction, wherein the magnetic field sensor device comprises at least a 2D Hall sensor or 3D Hall sensor, wherein the preferred sensor direction of the magnetic field sensor device is defined by a measuring channel of the Hall sensor, and wherein the magnet device is formed by a stator unit of the stator module for generating the stator fields for driving the mover.

This achieves the technical advantage that an efficient method for controlling the planar drive system may be provided. By embodying the magnetic field sensor device at the mover in the form of at least one 2D or 3D Hall sensor and by embodying the magnetic device at the stator module in the form of a stator unit or a plurality of stator conductors of the stator unit of the stator module the stator conductor or the stator unit of the stator module may be used to generate the magnetic orientation field, which is used to generate the stator field for controlling the mover.

The magnetic orientation field may thus be achieved via the controller of the planar drive system by driving the stator module. An additional component of the planar drive system for providing the magnetic field device may thus be avoided and the control for generating the magnetic orientation field may be achieved via the already implemented controller. Furthermore, by embodying the at least one 2D or 3D Hall sensor at the mover, a reliable and precise determination of the magnetic orientation field may be achieved by the magnetic field sensor device. Furthermore, the preferred sensor direction is clearly defined by at least one measuring channel of the Hall sensor.

For the purposes of the application, a measuring channel of the Hall sensor is an X, Y or Z measuring channel of the 2D or 3D Hall sensor.

According to an embodiment, the method further comprises:determining a plurality of values of the magnetic orientation field for a plurality of different alignments of the preferred mover direction relative to the preferred stator module direction in a determining step; anddetermining a relation between a value of the magnetic orientation field and an alignment of the preferred mover direction relative to the preferred stator module direction based on the plurality of values of the magnetic orientation field for the plurality of different alignments of the preferred mover direction relative to the preferred stator module direction in a relation determining step;wherein the alignment determining step comprises:comparing the measurement value of the component of the magnetic orientation field in parallel to the preferred sensor direction with the relation between a value of the magnetic orientation field and an alignment of the preferred mover direction relative to the preferred stator module direction in a comparing step.

This achieves the technical advantage of providing a precise and efficient method for controlling the planar drive system. For this purpose, a relation between the value of the magnetic orientation field and an alignment of the preferred mover direction relative to the preferred stator module direction is generated on the basis of a plurality of values of the magnetic orientation field recorded for a plurality of different alignments of the preferred mover direction relative to the preferred stator module direction. This relation between a value of the magnetic orientation field and a corresponding alignment of the preferred mover direction relative to the preferred stator module direction corresponding to a corresponding orientation of the mover relative to the stator module may be used to determine an alignment of the preferred mover direction relative to the preferred stator module direction performed to control the planar drive system in the alignment determining step, a value of the component of the magnetic orientation field measured for this purpose, oriented in parallel to the preferred sensor direction of the magnetic field sensor device is compared to corresponding values of the magnetic orientation field in accordance with the determined relation between the magnetic orientation field and the alignment of the preferred mover direction, and an alignment of the preferred mover direction corresponding to the measurement value of the magnetic orientation field is determined based on the relation between the value of the magnetic orientation field and a corresponding alignment of the preferred mover direction relative to the preferred stator module direction.

A relation between values of the magnetic orientation field and different orientations of the mover relative to the stator module may e.g. be stored in a corresponding look-up table. Alternatively, a relation may be expressed in a corresponding mathematical function that describes a unique assignment between values of the magnetic orientation field and different orientations of the mover.

This allows for simple and precise determining of the alignment of the preferred mover direction relative to the preferred stator module direction and thus an orientation of the mover relative to the stator module based on recorded measurement values of the magnetic orientation field.

According to an embodiment, the determining step comprises:recording a plurality of measurements of components of the magnetic orientation field in parallel to preferred sensor directions of the magnetic field sensor device for a plurality of different alignments of the preferred mover direction relative to the preferred stator module direction by the magnetic field sensor device in a measuring step; orcalculating the plurality of values of components of the magnetic orientation field in parallel to preferred sensor directions of the magnetic field sensor device for the plurality of different alignments of the preferred mover direction relative to the preferred stator module direction based on a model description of the magnetic orientation field in a simulating step.

This achieves the technical advantage that a precise and reliable determination of the orientation of the mover relative to the stator module may be achieved. For this purpose, in order to determine the relation between an expected measurement value of the magnetic orientation field for a specific orientation of the preferred mover direction relative to the preferred stator module direction, i.e.: a specific alignment of the mover relative to the stator module, for a plurality of different orientations of the mover relative to the stator module, a plurality of measurement values of a component of the magnetic orientation field parallel to the preferred sensor direction of the magnetic field sensor device are recorded for a plurality of different orientations of the mover relative to the stator module, respectively for a plurality of different alignments of the preferred mover direction relative to the preferred stator module direction.

On the basis of these measurement values, the corresponding relation between the expected measurement value of the magnetic orientation field and the associated alignment of the preferred mover direction relative to the preferred stator module direction may be made in the following. By measuring the plurality of measurement values of the magnetic orientation field for the plurality of different orientations of the mover relative to the stator module, a precise and reliable determination of the relation between the expected measurement value of the magnetic orientation field and a corresponding alignment of the preferred mover direction relative to the preferred stator module direction and, associated therewith, a relation between an expected value of the magnetic orientation field and a corresponding orientation of the mover relative to the stator module may be achieved. Hereby, the orientation of the mover may be determined precisely and reliably.

As an alternative, the plurality of values of the magnetic orientation field for a plurality of different orientations of the mover relative to the stator module may be achieved by a simulation based on a model description of the magnetic orientation field. Knowing the spatial configuration of the magnetic orientation field, expected measurement values of the magnetic orientation field may be calculated for any orientations of the mover relative to the stator module and a corresponding relation between magnetic orientation field and alignment of the preferred mover direction relative to the preferred stator module direction may be obtained based on the calculated values of the magnetic orientation field. This allows for the orientation of the mover relative to the stator module to be determined as precisely as possible. In addition, an individual relation between the magnetic orientation field and the alignment of the preferred mover direction relative to the preferred stator module direction or between the magnetic orientation field and the orientation of the mover relative to the stator module may be determined for each mover of the planar drive system. This allows for individual characteristics of individual movers to be taken into account, so that the most precise and accurate determination of the orientation may be achieved by recording a plurality of measurement values of the magnetic orientation field.

According to an embodiment, the comparison in the comparing step is carried out via an approximation method.

This provides the technical advantage that a precise and reliable determination of the alignment of the mover relative to the stator module may be achieved. By performing an approximation method for determining the alignment of the preferred mover direction relative to the preferred stator module direction in the course of a comparison of the recorded measurement values of the magnetic orientation field with the corresponding relation between expected values of the magnetic orientation field for arbitrary orientations of the mover relative to the stator module, it may be achieved that for arbitrary values of the magnetic orientation field the most precise determination of the associated orientation of the mover relative to the stator module is achievable.

The approximation method may e.g. be based on a least square method in which a difference between a measurement value of the component of the magnetic orientation field parallel to the preferred sensor direction and a value of the magnetic orientation field for a certain alignment of the preferred mover direction relative to the preferred stator module direction is minimized according to the relation, and thus the corresponding value of the magnetic orientation field of the relation is determined. Based on the relation, an orientation of the mover relative to the stator module corresponding to the measurement value of the magnetic orientation field may be determined.

In particular, if the relation comprises a look-up table in which values of the magnetic orientation field are assigned to orientations of the mover, the corresponding values of the magnetic orientation field of the look-up table may be determined via the least square method from the measurement values of the magnetic orientation field, on the basis of which the corresponding orientations of the mover relative to the stator module may then be determined via the allocation in the look-up table.

According to an embodiment, the mover further comprises a transmission unit arranged to transmit the measurement values of the magnetic orientation field recorded in the magnetic field determining step to the controller, and wherein the alignment determining step and the orientation determining step are performed by the controller.

This achieves the technical advantage that no additional components, in particular a processor unit, need to be embodied on the stator module to perform the alignment determining and orientation determining steps. By transmitting the corresponding data with the transmission unit formed on the mover, all calculation steps may be performed by the controller of the planar drive system. Thus, the method for controlling a planar drive system may be executed by any planar drive system with only one additional component in the form of the magnetic field sensor device.

According to an embodiment, the mover further comprises a processor unit configured to carry out the alignment determining step and the orientation determining step, and a transmission unit configured to transmit the alignment determined in the alignment determining step and/or the orientation determined in the orientation determining step to the controller.

This achieves the technical advantage that data transmission between the mover and the controller of the planar drive system may be achieved with the smallest possible data volume. With the processor unit formed at the mover, which is set up to carry out the alignment determining step and the orientation determining step and the associated evaluation of the recorded measurement values of the magnetic orientation field, it is achieved that instead of transmitting the measurement values of the magnetic orientation field recorded by the magnetic field sensor device from the mover to the controller, exclusively the evaluated data, in particular the calculated alignment of the preferred mover direction relative to the preferred stator module direction or the calculated orientation of the mover relative to the stator module, are transmitted to the controller for further processing. This may substantially reduce the volume of data to be transmitted and simplify and accelerate data transmission.

According to an embodiment, a power supply of the magnetic field sensor device is configured as a wireless power supply.

This achieves the technical advantage that no additional wiring of the mover of the planar drive system is required and, associated with this, a reduction in the freedom of movement of the mover on the stator module for power supply. A power supply to the magnetic field sensor device of the mover may be achieved via a wireless power supply in the form of a corresponding modulation of the stator field generated by the stator module. Apart from additional wiring, an additional energy source for supplying energy to the magnetic field sensor device may thus also be dispensed with.

According to an embodiment, the magnetic field sensor device of the mover comprises a plurality of 2D Hall sensors or a plurality of 3D Hall sensors, wherein measuring channels of the 2D or 3D Hall sensors are arranged parallel or antiparallel with regard to one another, respectively.

This has the technical advantage that the magnetic orientation field may be determined as precisely as possible and, associated with this, the orientation of the mover relative to the stator module may be determined as precisely as possible. By using a plurality of 2D or 3D Hall sensors, a plurality of independent measurement values of the magnetic orientation field may be recorded, thus increasing the precision of determining the magnetic orientation field and, associated with this, a determination of the orientation of the mover relative to the stator module. The alignment of the individual measuring channels of the multiple 2D or 3D Hall sensors in parallel or antiparallel orientation allows for taking all measurement values of the individual 2D or 3D Hall sensors into account for determining the magnetic orientation field and thus allows for a further increase of the precision and measurement accuracy.

According to an embodiment, the magnetic field sensor device of the mover comprises two 2D Hall sensors or 3D Hall sensors, wherein the two 2D Hall sensors or 3D Hall sensors are arranged at a distance from each other at the mover, and wherein a connecting line between the two 2D, 3D Hall sensors passes through a geometric center of the running surface of the mover.

This achieves the technical advantage that by positioning the two 2D or 3D Hall sensors outside a geometric center of the mover's running surface, scattering effects of the magnetic stator field and the magnetic orientation field that occur at edges of the stator module or at contact points between a plurality of stator segments of the stator module may be compensated for to determine the magnetic orientation field by arranging the two 2D or 3D Hall sensors at the mover in such a way that for each positioning of the mover on the stator module or on a plurality of stator modules arranged in a row, at least one of the two 2D or 3D Hall sensors is arranged outside of the area in which the stray field of the magnetic stator field or the magnetic orientation field occurs. In this way, a measurement accuracy of the magnetic orientation field may be achieved.

According to an embodiment, the magnetic field sensor device of the mover comprises three 2D Hall sensors or 3D Hall sensors, wherein the three 2D Hall sensors or 3D Hall sensors are arranged at a distance from one another on the mover and form a triangular arrangement, and wherein a geometric center of the running surface of the mover is arranged on a surface of the triangular arrangement formed by the three 2D Hall sensors or 3D Hall sensors or on a connecting line between two of the three 2D, 3D Hall sensors.

This achieves the technical advantage that a measurement accuracy of the magnetic orientation field may be further increased. By arranging three 2D or 3D Hall sensors in a triangular arrangement, in which none of the three 2D or 3D Hall sensors is arranged in the geometric center of the running surface of the mover, influences of the stray field of the magnetic stator field or of the magnetic orientation field, which occur at the edges of the stator module or at contact areas of a plurality of stator segments of a stator module, may be compensated for by arranging at least one 2D or 3D Hall sensor outside the areas of the stray field.

According to an embodiment, the magnetic orientation field is embodied as a static magnetic field.

This achieves the technical advantage that a further specification of the magnetic orientation field and, associated with this, a further specification of the determination of the orientation of the mover relative to the stator may be achieved.

According to an embodiment, the magnet device is embodied on the mover and the magnetic field sensor device is formed on the stator module, wherein the preferred stator module direction is identified with the preferred sensor direction and the preferred mover direction is identified with the preferred magnetic field direction, wherein the magnetic field sensor device comprises at least one magnetic field sensor of the sensor module of the stator module, wherein the at least one magnetic field sensor is formed as a 2D Hall sensor or 3D Hall sensor, wherein the preferred sensor direction of the magnetic field sensor device is defined by one of the measuring channels of the Hall sensor, wherein the magnet device is embodied as at least one permanent magnet, and wherein the preferred magnetic field direction is formed by a north pole and a south pole of the permanent magnet.

This achieves the technical advantage of providing the simplest possible solution for generating the magnetic orientation field. For this purpose, the magnetic field device is embodied on the mover, while the magnetic field sensor device is embodied by the magnetic field sensors of the sensor module of the stator module. In this case, the magnetic field device on the mover may be embodied as a permanent magnet so that the simplest possible magnetic orientation field may be generated. By realizing the magnetic field sensor device by the magnetic field sensors of the sensor module of the stator module, no additional component is required for realizing the magnetic field sensor device. Furthermore, the created measurement values of the magnetic field sensor device may be transmitted to the controller via the usual data connection between the stator module and the controller. A further device for data transmission may thus also be avoided.

Further, a planar drive system comprising at least one controller, a stator module having a stator surface, and a mover positionable on the stator surface is provided, the stator module being arranged to generate magnetic stator fields for electrically controlling the mover along the stator surface, wherein the mover has a magnet assembly for generating a magnetic mover field, wherein a magnetic coupling between the mover and the stator module is achievable via the magnetic stator fields and the magnetic mover field, wherein the stator module comprises a sensor module with a plurality of magnetic field sensors for determining a position of the mover, wherein the stator module or the mover comprise a magnet device for generating an magnetic orientation field, the magnetic orientation field being rotationally asymmetric with respect to rotation about a rotational axis perpendicular to the stator surface and having a preferred magnetic field direction and wherein the respective other of the stator module and the mover comprises a magnetic field sensor device having a preferred sensor direction for detecting the magnetic orientation field along the preferred sensor direction, and wherein the planar drive system is embodied to perform the method for controlling a planar drive system According to an embodiment.

Herein, a planar drive system may be provided that has precise and improved control and is configured to carry out the method of the application with the aforementioned advantages.

FIG.1shows a schematic view of a planar drive system200with a stator module300and a mover400.

According to the embodiment inFIG.1, the planar drive system comprises a controller201, a stator module300and a mover400. The controller201is connected to the stator module300via a data link203. The controller201is arranged to carry out a method100according to the application for controlling a planar drive system200.

For a detailed description of the method according to the application for controlling a planar drive system200and the operation of the position assignment function205, please refer to the description forFIG.4,FIG.5,FIG.7andFIG.9.

The stator module300has a planar stator surface303. The planar stator surface303is arranged on an upper surface of a stator module housing305. A mover400is disposed above the stator surface303. The stator surface303is part of a stator unit307for an electric drive of the mover400. The stator unit307with the stator surface303may be embodied as a printed circuit board. The stator surface303has a square shape.

The stator unit307has four stator segments308that are connected to electronic modules within the stator module housing305via a contact structure310.

The mover400may be driven above the stator surface303in at least a first direction507and a second direction509. The stator surface303comprises a plurality of stator conductors309, which in the embodiment shown inFIG.1are stator conductors309that are substantially aligned along the first direction507. The stator conductors309are embodied to conduct current and may be energized to drive the mover400. A stator conductor gap311is provided between the stator conductors309, through which the stator conductors309are electrically isolated from each other. Below the stator surface303, another arrangement of stator conductors may be provided in which the stator conductors are substantially aligned along the second direction509.

The stator module housing305comprises electronic modules for driving and controlling the mover400. For example, the electronic modules may include power modules for generating the drive currents and control modules for controlling the power modules and the drive currents. On a bottom surface of the stator module housing305opposite the stator surface303, connections are arranged for connecting the stator module300to a plurality of connecting lines. For example, the connecting lines may include a control line for transmitting control signals for the control modules and a power supply line for supplying electrical power to the power and/or control modules. In particular, electrical energy may be supplied to the power module via the power supply line to generate the drive currents.

The stator module housing305, the stator unit307and the stator surface303are rectangular, in particular square, in the top view of the stator surface303.

The stator module housing305comprises a sectional plane313. A sensor module may be disposed within the stator module housing305at the level of the sectional plane313.

InFIG.1, the mover400is provided with a preferred mover direction441. This may be arbitrarily selected and serves exclusively to determine an orientation of the mover400relative to the stator module300. The stator module300is provided with a likewise selectable preferred stator module direction315. InFIG.1, both preferred directions are arranged in parallel. However, this is not necessary and may be changed as desired. Further, a rotational axis317is shown oriented perpendicularly with regard to the stator surface303and passing through a geometric center445of the mover400.

FIG.2shows a perspective view of a sensor module500for detecting a position of the mover400in the planar drive system200. The sensor module500is arranged in a rectangular shape and has a two-dimensional arrangement of magnetic field sensors501on a carrier301of the stator module300. The magnetic field sensors501are arranged on the carrier301. The two-dimensional array of magnetic field sensors501includes a first periodic grid503of magnetic field sensors501and a second periodic grid505of magnetic field sensors501. The magnetic field sensors501of the first grid503are indicated by round symbols, while the magnetic field sensors501of the second grid505are indicated by square symbols.

Provided that reference is made to magnetic field sensors501in general terms for the purposes of the application, reference501is used.

The first magnetic field sensors511are connected with solid lines to illustrate the grid structure of the first grid503. The second magnetic field sensors513are connected with dashed lines to illustrate the grid structure of the second grid505. The first magnetic field sensors511and the second magnetic field sensors513may be identical, and the round or square symbols, respectively, are only intended to symbolize the positions of the magnetic field sensors501associated with the respective sub-arrays.

The first grid503and the second grid505have identical structures and are shifted with regard to each other. As a result, the second magnetic field sensors513of the second grid505and the first magnetic field sensors511of the first grid503are each shifted with regard to one another.

The arrangement of magnetic field sensors501shown inFIG.2is for illustrative purposes only and may differ from the arrangement shown inFIG.2.

The magnetic field sensors501are each set up to determine magnetic fields for a spatial area. Measurements of a magnetic field sensor501are thus limited to the respective spatial area of the respective magnetic field sensor501. The spatial regions of the magnetic field sensors501may have geometrically arbitrarily embodied spatial extents and may e.g. be circular in shape. In particular, the spatial regions may have a point-shaped configuration, so that point measurements of the respective magnetic fields may be performed by the magnetic field sensors501, in which individual magnetic field sensors501exclusively measure field contributions of the respective magnetic fields that are arranged directly at the positions of the respective magnetic field sensors501.

The carrier301is planar so that the magnetic field sensors501are arranged in a plane, i.e., in a two-dimensional array.

The magnetic field sensors501may be embodied as Hall sensors. In particular, the magnetic field sensors501may be embodied as 2D or 3D Hall sensors, wherein 3D Hall sensors measure the magnetic field components in three linearly independent spatial directions. In particular, these spatial directions may include the first direction507and the second direction509as well as a third direction perpendicular to the first direction507and the second direction509.

The carrier301may be embodied as a printed circuit board and/or a circuit board. Thus, the carrier301may be provided in a simple way.

The array of magnetic field sensors501may comprise exactly two sub-arrays of the two grids503,505.

FIG.3shows the mover400of the planar drive system200in a bottom view of an underside of the mover400. In operation of the planar drive system200, the underside of the mover400is arranged facing the stator surface303of the stator module300. The mover400comprises a magnet assembly401on the underside thereof. The magnet assembly401is rectangular, in particular square, in shape and comprises a plurality of magnets. The underside of the mover400is flat or planar, in particular in the area of the magnets of the magnet assembly401. In operation, the underside of the mover400with the magnet assembly401is oriented substantially parallel to the stator surface303and is arranged facing the stator surface303.

The magnet assembly401comprises a first magnet unit411, a second magnet unit413, a third magnet unit415, and a fourth magnet unit417. The first magnet unit411and the third magnet unit415each comprise elongated drive magnets arranged side-by-side in a first mover direction407and extending along a second mover direction409oriented perpendicular to the first mover direction407. The second magnet unit413and the fourth magnet unit417each have elongated drive magnets arranged side by side in the second mover direction409and extending along the first mover direction407. In operation, the first and third magnet units411,415serve to drive the mover400in the first mover direction407, and the second and fourth magnet units413,417serve, in operation, to drive the mover400in the second mover direction409. Moreover, all of the magnet units413,417serve to drive in a direction perpendicular with regard to the stator surface303.

In the center of the magnet assembly401, the mover400has a free surface403that is not covered by magnets of the magnet assembly401. In the area of the free surface403, the mover400has a fastening structure405.

FIG.4shows a flowchart of the method100for controlling a planar drive system200according to an embodiment.

The method100shown inFIGS.4,5and7is carried out with reference to the description ofFIGS.1to3,6and7to11.

The method100for controlling a planar drive system200may be applied to a planar drive system200comprising a controller201, a stator module300having a stator surface303, and a mover400that may be positioned on the stator surface303. The stator module300is configured to generate magnetic stator fields for electrically controlling the mover400along the stator surface303, wherein the mover400comprises a magnet assembly401for generating a magnetic mover field. A magnetic coupling between the mover400and the stator module300is achievable via the magnetic stator fields and the magnetic mover field. The stator module300includes a sensor module500having a plurality of magnetic field sensors501for determining a position of the mover400.

Moreover, the stator module300or the mover400include a magnetic device419for generating an magnetic orientation field, the magnetic orientation field being rotationally asymmetric with respect to rotation about a rotational axis317perpendicular to the stator surface303and having a preferred magnetic field direction319. The other component of each of the stator module300and the mover400comprise a magnetic field sensor device424having a preferred sensor direction443for detecting the magnetic orientation field along the preferred sensor direction443.

In a preferred direction identifying step101, a preferred stator module direction315of the stator module300is identified with the preferred magnetic field direction319or the preferred sensor direction443, and a preferred mover direction441of the mover400is identified with the respective other of the preferred magnetic field direction319or the preferred sensor direction443.

In this regard, the preferred stator module direction315is any direction parallel to the stator surface303for orientation of the mover400relative to the stator module300. The preferred mover direction441is an arbitrarily selectable direction parallel to a running surface402arranged on a bottom surface of the mover400, and serves to orient the mover400relative to the stator module300by determining an alignment of the preferred mover direction441relative to the preferred stator module direction315.

In the present case, the preferred magnetic field direction319is given by an axis of symmetry of the magnetic orientation field and is oriented in parallel to the running surface402of the mover400or in parallel to the stator surface303of the stator module300, depending on whether the magnetic device419is arranged at the mover400or at the stator module300.

The magnetic field sensor device424may be embodied by one or a plurality of 2D/3D Hall sensors. The preferred sensor direction443of the magnetic field sensor device424is thus defined by the alignment of the measuring channels of the 2D/3D Hall sensors, in particular by the X, Y or Z measuring channels.

After identifying the preferred stator module direction315and the preferred sensor direction443, the magnetic orientation field is set by the magnetic device419in a magnetic field setting step103.

Subsequently, at least one measurement value of the magnetic orientation field is determined by the magnetic field sensor device424in a magnetic field determining step105. Here, the at least one measurement value of the magnetic orientation field comprises at least one value of a component of the magnetic orientation field in a direction parallel to the preferred sensor direction443. If the magnetic field sensor device424is embodied by at least one 2D/3D Hall sensor, the measurement value recorded by the 2D/3D Hall sensor comprises at least one component of the X, Y or Z measuring channel of the 2D/3D Hall sensor.

Subsequently, in an alignment determining step107, an alignment of the preferred mover direction441relative to the preferred stator module direction315is determined on the basis of the measurement value of the component of the magnetic orientation field parallel to the preferred sensor direction443. For example, the alignment of the preferred mover direction441relative to the preferred stator module direction315may be indicated by an angle between the two preferred directions. Since the preferred mover direction441or the preferred stator module direction315coincides with the preferred sensor direction443or the preferred magnetic field direction319, depending on whether the magnetic device419is embodied at the mover400or at the stator module300and the magnetic field sensor device424is correspondingly embodied at the respective other component, an alignment between the preferred mover direction441and the preferred stator module direction315may be determined via a determination of the alignment of the preferred magnetic field direction319relative to the preferred sensor direction443.

If the measurement of the at least one measurement value of the magnetic orientation field by the magnetic field sensor device424determines that the preferred sensor direction443of the magnetic field sensor device424is oriented parallel or anti-parallel to the preferred magnetic field direction319, it may be concluded therefrom that the preferred mover direction441is aligned parallel or anti-parallel relative to the preferred stator module direction315.

The determination of the alignment of the preferred mover direction441relative to the preferred stator module direction315described herein is based on the idea that measurement values of a component of the magnetic orientation field for different orientations of the preferred sensor direction443relative to the preferred magnetic field direction319result in different values of the component of the magnetic orientation field. Thus, a maximum value of the x component of the magnetic orientation field is measured for an alignment of the preferred sensor direction443, e.g. given by an X channel of a 3D Hall sensor, parallel to the preferred magnetic field direction319, e.g. given by the x component of the magnetic orientation field. For an orientation of the mover400for which the preferred sensor direction443given by the X-channel of the 3D Hall sensor has a substantial angle to the preferred magnetic field direction319given by the x-component of the magnetic orientation field, a measurement value of the magnetic orientation field recorded by the X-channel of the 3D Hall sensor has a value substantially different from the maximum value of the x-component of the magnetic orientation field.

Thus, by determining the deviations of recorded measurement values of the magnetic orientation field, or a component of the magnetic orientation field, from the maximum value of the respective component of the magnetic orientation field, orientations of the preferred sensor direction443relative to the preferred magnetic field direction319and associated orientations of the mover400relative to the stator module300may be determined by recording measurement values of the magnetic orientation field.

Analogously, conclusions may be drawn about the alignment of the two preferred directions, and thus the orientation of the mover400relative to the stator module300, for any other angles between the preferred sensor direction443of the magnetic field sensor device424and the preferred magnetic field direction319of the magnetic orientation field.

Subsequently, an orientation determining step109determines a first orientation of the mover400relative to the stator module300based on the alignment of the preferred mover direction441relative to the preferred stator module direction315.

For purposes of the application, an orientation of the mover400relative to the stator module300includes rotation of the mover400about a rotational axis317oriented perpendicularly with regard to the stator surface303and passing through a geometric center of the mover400. In contrast, an orientation of the mover400relative to the stator module300does not include translational movement of the geometric center of the mover400relative to the stator module300.

FIG.5shows another flowchart of the method100for controlling a planar drive system200according to another embodiment.

The embodiment inFIG.5is based on the embodiment inFIG.4and includes all the method steps fromFIG.4, which are not described again below to avoid unnecessary repetition.

After identifying the preferred directions in the preferred direction identifying step101, a position determining step111determines a position of the mover400relative to the stator module300. Here, a position of the mover400relative to the stator module300does not include an orientation of the mover400relative to the stator module300. Two different positions of the mover400relative to the stator module300may be merged here by any number of translational movements of the mover400relative to the stator module300. A determination of the position of the mover400relative to the stator module300is realized by recording a plurality of measurement values of the magnetic mover field of the mover400by the magnetic field sensors501of the sensor module500.

Subsequently, in a locking step113, a magnetic locking field is set by which the mover400is locked in the position relative to the stator module300previously determined in the position determining step111. The magnetic locking field is in this context provided by the stator conductors309of the stator units307of the stator module300. The magnetic locking field is in this context provided by the stator module300in such a way that an attractive magnetic coupling is generated between the magnetic mover field of the mover400and the magnetic locking field of the stator module300in a z-direction perpendicular to the stator surface303of the stator module300, which attracts the mover400to the stator surface303of the stator module300and holds it in the locked position. Following this, an orientation of the mover400relative to the stator module300in the locked position is determined in the method steps described with respect toFIG.4.

After determining the orientation of the mover400relative to the stator module300in the orientation determining step109, in an orientation step115, the first orientation of the mover400relative to the stator module300determined in the orientation determining step109is changed to a second orientation of the mover400relative to the stator module300. For this purpose, the locking of the mover400in the determined position relative to the stator module300may additionally be released by setting the magnetic locking field in the locking step113, so that a movement of the mover400relative to the stator module300is allowed for.

In addition to changing the first orientation of the mover400to the second orientation of the mover400relative to the stator module300, further control of the mover400and associated translational movement of the mover400relative to the stator module300may be performed.

FIG.6shows a schematic diagram of a mover400and a stator module300according to an embodiment.

FIG.6shows a stator module300and a mover400ofFIG.1. The details of the two components described therein are not described again in detail below.

At the mover400, the magnetic field sensor device424is embodied as a 2D/3D Hall sensor427arranged on a mover circuit board425. On the stator module300, the magnetic device419is embodied accordingly, which in the embodiment inFIG.6is as stator conductors309of the stator segments308of the stator unit307of the stator module300.

The opening shown on the mover400inFIG.6is only to illustrate the magnetic field sensor device424embodied on the underside of the mover400.

In the embodiment shown inFIG.6, the 2D/3D Hall sensor427is embodied as a 3D Hall sensor and has a first measuring channel435, a second measuring channel437and a third measuring channel439. The three measuring channels are each arranged at right angles with regard to one another and allow for measurement of the magnetic orientation field in parallel or anti-parallel directions with regard to the respective measuring channel. Due to the plurality of measuring channels of the 2D/3D Hall sensors, different components of the magnetic orientation field may be determined.

Depending on the alignment, the magnetic stator field or magnetic orientation field generated by the stator conductors309of the stator module300has an x-component Bx, a y-component By oriented perpendicularly thereto, and a z-component Bz oriented perpendicularly thereto in turn. In the embodiment shown inFIG.6, the 3D Hall sensor of the magnetic field sensor device424is oriented such that the first measuring channel435is oriented in parallel to the x-component Bx of the magnetic stator field or the magnetic orientation field, while the second measuring channel437is oriented in parallel to the y-component By and the third measuring channel439is oriented in parallel to the z-component Bz. InFIG.6, the first measuring channel435is further identified as the preferred sensor direction443. The identification of the first measuring channel435with the preferred sensor direction443is purely exemplary, and an identification of the preferred sensor direction443with the second measuring channel437is possible, as well. Furthermore, in the embodiment shown inFIG.6, the preferred mover direction441is identified with the preferred sensor direction443, while the preferred stator module direction315is identified with the x-component Bx of the magnetic orientation field. As mentioned above, the preferred directions of the stator module300and the mover400may be chosen arbitrarily and only serve to determine the orientation of the rotationally symmetrical mover400relative to the stator module300.

As an alternative to the embodiment shown inFIG.6, the magnetic field sensor device424may comprise a plurality of 2D/3D Hall sensors427.

FIG.7shows another flowchart of the method100for controlling a planar drive system200according to another embodiment.

The embodiment of the method100shown inFIG.7refers to the embodiment shown inFIG.6, in which the magnetic field sensor device424is embodied on the mover400, while the magnetic device419is formed by the stator conductors309of the stator unit307of the stator module300.

With regard to the method steps, the embodiment inFIG.7is based on the embodiment inFIG.5and comprises all the method steps described there, which are not described again in detail below.

In the embodiment shown inFIG.7, the method100further comprises a determining step117for determining a plurality of values of the magnetic orientation field for a plurality of different alignments of the preferred mover direction441relative to the preferred stator module direction315. Thus, in the determining step117, values of the magnetic orientation field expected for each orientation may be recorded for different alignments of the mover400relative to the stator module300involving different orientations of the preferred mover direction441relative to the preferred stator module direction315as described above.

This may be done either by appropriate measurements or alternatively by calculations in appropriate simulations.

For this purpose, in a measuring step123, measurement values of the magnetic orientation field parallel to the preferred sensor direction443of the at least one 2D/3D Hall sensor427of the magnetic field sensor device424may be recorded for different alignments of the mover400relative to the stator module300and, associated therewith, for different orientations of the mover preference direction441relative to the stator module preference direction315. For this purpose, e.g. the mover400may be positioned in different orientations on the stator module300and corresponding orientation fields may be set in order to record corresponding measurement values of the magnetic orientation field for the individual orientations of the mover400relative to the stator module300.

Preferably, the measuring step123may be carried out prior to performing control of the mover400on the stator module300as a calibration or adjustment of the control system. For this purpose, a corresponding data set of measurement values of the magnetic orientation field for any orientations of the mover400relative to the stator module300may be recorded for each mover400of the planar drive system200to be controlled. Alternatively, a data set for a reference mover may be recorded to be used as reference data set for controlling all movers400of the planar drive system200.

As an alternative to measuring the individual measurement values of the magnetic orientation field in the measuring step123, the expected values of the magnetic orientation field may be simulated in a corresponding simulation for various orientations of the mover400relative to the stator module300in a simulating step125. This may be carried out on the basis of a model description of the spatial configuration of the magnetic orientation field by calculating corresponding values of the magnetic orientation field, in particular components of the magnetic orientation field parallel or antiparallel to the preferred sensor direction443, for any orientation of the mover400relative to the stator module300.

Further, the embodiment shown inFIG.7comprises, for determining the alignment of the preferred mover direction441relative to the preferred stator module direction315in the alignment determining step107, determining a relation between expected measurement values of the magnetic orientation field and a corresponding alignment of the preferred mover direction441relative to the preferred stator module direction315and, associated therewith, to an alignment of the mover400relative to the stator module300in a relation determining step119based on the values of the magnetic orientation field determined in the determining step117. This relation between the values of the magnetic orientation field and different orientations of the mover400relative to the stator module300may e.g. be stored in a corresponding look-up table in which different orientations of the mover400relative to the stator module300are associated with corresponding values of the magnetic orientation field. Alternatively, the relation may be stored in a mathematical relation or function.

Further, for determining the alignment of the two preferred directions in the alignment determining step107, the at least one measurement value of the magnetic orientation field recorded in the magnetic field determining step105is compared with the values of the relation determined in the relation determining step119. This comparison process carried out in the comparing step121may be performed based on an approximation method in which the best fitting value of the magnetic orientation field of the relation is identified for the measurement value of the magnetic orientation field.

For example, the approximation method may be based on a least square method in which a difference between a measurement value of the component of the magnetic orientation field parallel to the preferred sensor direction443and a value of the magnetic orientation field for a particular alignment of the preferred mover direction441relative to the preferred stator module direction315is minimized in accordance with the relation, and thus the corresponding value, i.e., the value of the magnetic orientation field of the relation that deviates the least from the measurement value of the magnetic orientation field, is determined. On the basis of the relation, an orientation of the mover400relative to the stator module300corresponding to the measurement value of the magnetic orientation field may be determined.

In particular, if the relation comprises a look-up table in which values of the magnetic orientation field are associated with orientations of the mover400, the corresponding values of the magnetic orientation field of the look-up table may be determined via the least square method to the measurement values of the magnetic orientation field, based on which the corresponding orientations of the mover400relative to the stator module300may then be determined via the association of the look-up table.

The comparing step121thus first selects the most suitable value of the magnetic orientation field of the relation for the recorded measurement value of the magnetic orientation field and, associated therewith, assigns the corresponding alignment of the preferred mover direction441relative to the preferred stator module direction315of the relation to the measurement value of the magnetic orientation field. Thus, for a recorded measurement value of the magnetic orientation field, a corresponding orientation of the mover400relative to the stator module300or, associated therewith, a corresponding alignment of the preferred mover direction441relative to the preferred stator module direction315may be determined.

As an alternative to the embodiment shown inFIG.6, the magnetic field sensor device424may comprise a plurality of 2D/3D Hall sensors427. Furthermore, a plurality of measurement values of the magnetic orientation field may be recorded in the magnetic field determining step105.

The measurement values of the magnetic orientation field mentioned herein may in particular comprise several components of the magnetic orientation field in that the magnetic field sensors are embodied as 2D/3D Hall sensors and thus have at least two different measuring channels via which at least two components of the magnetic orientation field may be measured.

The measurement values of the magnetic orientation field recorded by the magnetic field sensor device424may be transmitted to the controller201of the planar drive system200via a transmission device, and may be evaluated by the controller201according to the alignment determining step107and the orientation determining step109. Alternatively, the execution of the alignment determining step107and orientation determining step109may be carried out by a processor unit embodied at the mover400. Furthermore, a power supply to the magnetic field sensor device424may be achieved by a wireless power supply, in which an inductive power supply to the magnetic field sensor device424is achieved via a corresponding modulation of the magnetic stator field or magnetic orientation field generated by the stator module300.

FIGS.8A to8Cillustrate three different embodiments of the magnetic field sensor device424, each having one 2D/3D Hall sensor, two 2D/3D Hall sensors, or three 2D/3D Hall sensors.

FIG.8Ashows a further schematic depiction of a mover400and a stator module300according to another embodiment.

FIG.8Ashows a stator module300and a mover400placed thereon. The mover400includes the magnetic field sensor device424, which in the embodiment shown inFIG.8Aincludes the mover circuit board425and a 2D/3D Hall sensor427placed thereon. InFIGS.8A to8C, the mover400is reduced to the mover circuit board425and the Hall sensors placed thereon, as the sole purpose is to illustrate the effect of the placement of each Hall sensor on effects of the magnetic orientation field of the stator module300.

InFIG.8A, the one 2D/3D Hall sensor427is arranged at the geometric center445of the mover400.

Due to edge effects occurring respectively at the edges of the stator module300or at the contact structure310, areas arise at the respective contact structures310or at the edges of the stator module300in which an exact determination of the magnetic orientation field by the magnetic field sensor device424cannot be guaranteed. These areas are shown inFIGS.8A to8Cby the vertical and horizontal dashed line ellipses, respectively.

InFIGS.8A to8C, only one stator module300is shown. However, for an operation of a planar drive system200, usually a plurality of stator modules300is arranged in combination to form a large area drive surface of the planar drive system200. For operating the mover400on the plurality of stator modules300, in the embodiment ofFIG.8Ain which a single 2D/3D Hall sensor427is arranged in the geometric center445of the mover400, the problem that when the mover400crosses the contact structures310or the edges of the individual stator modules300, the single 2D/3D Hall sensor427enters the areas marked with the dashed ellipses, in which no unambiguous determination of the magnetic orientation field is possible due to the prevailing edge effects, so that, if necessary, no unambiguous determining of the magnetic orientation field and, associated therewith, no unambiguous determining of the orientation of the mover400relative to the stator module300may be provided.

FIG.8Bshows another schematic depiction of a mover400and a stator module according to a further embodiment.

In the embodiment ofFIG.8B, in contrast to the embodiment ofFIG.8A, the magnetic field sensor device424comprises a first 2D/3D Hall sensor429and a second 2D/3D Hall sensor431that are spaced apart from each other at opposite edges of the mover PCB425. A connecting line between the two 2D/3D Hall sensors passes through the geometric center445of the mover400. Such an arrangement of the two first and second 2D/3D Hall sensors means that the edge effects at the two lateral edges of the illustrated stator module300for determining the magnetic orientation field by the first 2D/3D Hall sensor429and the second 2D/3D Hall sensor431or by the magnetic field sensor device424do not lead to negative effects. This may be achieved by the fact that during a right-left movement of the mover400over the right or left edge of the stator module300shown inFIG.8Bor over the edges of the stator module arranged vertically inFIG.8Band the vertical contact structure310, in each position of the mover400relative to the stator module300, one of the two 2D/3D Hall sensors is arranged outside of the area in which a clear determination of the magnetic orientation field is not possible due to the edge effects. This effect is illustrated inFIG.8Bby the omission of the vertically arranged dash-lined ellipses, demonstrating that the arrangements of the 2D/3D Hall sensors shown inFIG.8Bmay compensate for the edge effects of the vertically oriented edges or contact structures310.

FIG.8Cshows another schematic depiction of a mover400and a stator module300according to another embodiment.

In the embodiment shown inFIG.8C, the magnetic field sensor device424comprises a first 2D/3D Hall sensor429, a second 2D/3D Hall sensor431, and a third 2D/3D Hall sensor433arranged in a triangular array. The arrangement of the three 2D/3D Hall sensors shown inFIG.8Censures that, for any positioning of the mover400relative to the stator module300, at least one of the three 2D/3D Hall sensors of the magnetic field sensor device424is arranged outside the areas shown in dashed lines inFIG.8A, in which, due to the edge effects, an unambiguous determination of the magnetic orientation field is not possible for magnetic field sensors501arranged in these areas. The arrangement of the three 2D/3D Hall sensors shown inFIG.8Cthus allows for an unambiguous determination of the magnetic orientation field by the magnetic field sensor device424for any positioning of the mover400on the stator module300. Deviating from the arrangement shown inFIG.8C, an alternative triangular arrangement of the three 2D/3D Hall sensors may also lead to the described effect.

Alternatively, the magnetic field sensor device424may be equipped with any number of 2D/3D Hall sensors.

FIG.9shows another schematic depiction of a mover400and a stator module300according to another embodiment.

FIG.9shows a stator module300having a mover400. The mover400is reduced to four magnetic units411,413,415,417and the magnetic field sensor device424comprising a first 2D/3D Hall sensor429, a second 2D/3D Hall sensor431, and a third 2D/3D Hall sensor433.

In the embodiment shown inFIG.9, the first measuring channel435of the first 2D/3D Hall sensor429is arranged antiparallel to the x-component Bx of the magnetic field of the stator module300. The second measuring channel437of the first 2D/3D Hall sensor429is further arranged antiparallel to the y-component By of the magnetic field of the stator module300. Depending on the alignment of the magnetic orientation field along the x-component Bx or the y-component By, corresponding components of the magnetic orientation field may thus be determined in the orientation of the mover400relative to the stator module300shown inFIG.9via the corresponding first or second measuring channels435,437of the first to third 2D/3D Hall sensors429,431,433.

Changing the orientation of the mover400relative to the stator module300, e.g. by rotating it about the axis of rotation, changes the values recorded by the first measuring channels435or second measuring channels437of the first through third 2D/3D Hall sensors429,431,433, so that an orientation of the mover400relative to the stator module300may be determined based on the changes in the individual measurement values of the magnetic orientation field of the first through third 2D/3D Hall sensors429,431,433.

For this purpose, the measurement values recorded for different orientations by the 2D/3D Hall sensors429,431,433may be compared to corresponding measurement values recorded for different orientations of the mover400relative to the stator module300as reference values and stored in a look-up table. The comparisons of the recorded measurement values with the reference values stored in the look-up table may be used to determine corresponding orientations of the mover400relative to the stator module300by determining the values in the look-up table that have the least deviation from the recorded measurement values of the magnetic orientation field, and determining the corresponding orientations associated with the selected values of the magnetic orientation field in the look-up table.

The three 2D/3D Hall sensors are further arranged such that measuring channels of the individual Hall sensors are aligned parallel or antiparallel with regard to each other. For example, in the embodiment shown inFIG.9, the first measuring channel435of the first 2D/3D Hall sensor429is arranged antiparallel to the first measuring channel435of the second 2D/3D Hall sensor431and to the second measuring channel437of the third 2D/3D Hall sensor433. Accordingly, the second measuring channel437of the first 2D/3D Hall sensor429is arranged parallel to the first measuring channel435of the third 2D/3D Hall sensor433and antiparallel to the second measuring channel437of the second 2D/3D Hall sensor431.

Such an arrangement, in which the measuring channels of the individual Hall sensors are aligned parallel or antiparallel to each other, allows individual measurement values of the magnetic orientation field recorded by the various Hall sensors to be used to determine the magnetic orientation field.

Alternatively, the 2D/3D Hall sensors may also be arranged differently with regard to the arrangement shown inFIG.9on the mover400, so that the measuring channels of the individual Hall sensors are aligned parallel or antiparallel with regard to each other as desired.

FIG.10shows a further schematic depiction of a mover400according to a further embodiment.

In the embodiment ofFIG.10, the magnetic field sensor device424comprises four 2D/3D Hall sensors427, a first 2D/3D Hall sensor429, a second 2D/3D Hall sensor431, a third 2D/3D Hall sensor433, and a fourth 2D/3D Hall sensor434, which are not arranged in the center of the magnet assembly401, as in the embodiment inFIG.9, but in a mounting space of the mover400laterally surrounding the magnet assembly401. In the embodiment ofFIG.10, the four 2D/3D Hall sensors427are each individually arranged on a mover circuit board425. In the embodiment ofFIG.10, the four 2D/3D Hall sensors427are each arranged on one side of the mover400. However, a different arrangement is also conceivable.

In the embodiment shown inFIG.10, the four 2D/3D Hall sensors427are interconnected via wiring449.

The alignment of the individual measuring channels of435,437,439of the 2D/3D Hall sensors427is shown inFIG.6. Analogous to the embodiment inFIG.9, the 2D/3D Hall sensors427may be arranged in such a way that the measuring channels435,437,439of different 2D/3D Hall sensors427are each aligned parallel or antiparallel with regard to each other. However, a different alignment of the measuring channels435,437,439is possible, as well.

For example, the 2D/3D Hall sensors427may be arranged in a bumper of the mover400that laterally surrounds the mover400and absorbs impacts with other movers400or obstacles. As an alternative to the embodiment shown inFIG.10, the magnetic field sensor device424may comprise a different number of 2D/3D Hall sensors427arranged in one or more bumpers at the periphery of the mover400. In particular, the 2D/3D Hall sensors427may be arranged on one or any number of mover circuit boards425.

In the embodiment shown inFIG.10, the mover400further comprises a coil unit447that may be used for power transfer and/or for communication between the mover400and the stator module300. The coil unit447may be located in a structural space of the mover400laterally surrounding the magnet assembly401, such as in the bumpers. Alternatively, the coil unit447may be embodied as a printed coil on the mover circuit board425of the magnetic field sensor device424itself.

The 2D/3D Hall sensors427may be connected to the coil unit447via the wiring449.

Contrary to the illustration ofFIG.10, the magnet assembly401may also be embodied in such a way that no free surface is formed in the center of the magnet assembly401. Advantages here are that without a free surface in the center of the mover400, the dimensions of the mover400may be embodied smaller and thus more movers400may be used on a given stator surface303.

Furthermore, by an embodiment of the coil unit447according toFIG.10, a higher electrical power may be transmitted and a greater distance between the mover400and the stator module300may be maintained during power and data transmission than in the embodiment as a printed coil on the mover circuit board425according to the placement of the mover circuit board425in the center of the magnet assembly401according toFIG.6. Thus, power and data transmission may be carried out even during normal operation of the planar drive system200, e.g. while the mover400is being driven.

FIG.11shows another schematic view of an underside of a mover400according to another embodiment.

InFIG.11, the mover400ofFIG.3is shown, wherein in the embodiment ofFIG.11, the magnetic device419is embodied as a first permanent magnet421and a second permanent magnet423is formed on the mover400. Furthermore, in the embodiment shown inFIG.11, the preferred magnetic field direction319is defined by the alignment of the second permanent magnet423.

According to the embodiment shown inFIG.11, the magnetic field sensor device424is formed by the magnetic field sensors501of the sensor module500of the stator module300. As an alternative to the embodiment shown inFIG.11, the magnetic device419may be implemented by any number of different permanent magnets. A condition for this is that an arrangement of the arbitrary number of permanent magnets of the magnet device419is rotationally asymmetrical with respect to a rotational axis317perpendicular to the running surface402of the mover400.

With the rotationally asymmetric arrangement of the permanent magnets of the magnet device419with respect to the axis of rotation317, an orientation of the mover400relative to the stator module300may be unambiguously determined by the magnetic field sensors501of the sensor module500forming the magnetic field sensor device424based on the rotationally asymmetric magnetic orientation field generated by the rotationally asymmetric arrangement of the permanent magnets.

This invention has been described with respect to exemplary examples. It is understood that changes can be made and equivalents can be substituted to adapt these disclosures to different materials and situations, while remaining with the scope of the invention. The invention is thus not limited to the particular examples that are disclosed, but encompasses all the examples that fall within the scope of the claims.