Device and method for preventing a collision when driving at least two moving elements on a driving surface

A device and method for preventing a collision when determining travel paths for at least two movers on a drive surface, each mover comprising at least a second magnetic field generator, the device comprising a plurality of sectors, the sectors comprising magnetic field generators for generating magnetic fields, the sectors forming the drive surface. A path planning for at least two movers is carried out, at least the two movers being assigned a priority, the priorities of the movers being taken into account in the path planning such that a path of a mover is assigned a priority in the path planning of the travel paths of the movers, and a travel path of a mover with a higher priority takes precedence over a travel path of a mover with a lower priority, so that a collision of the movers is prevented.

FIELD

The present invention relates to a method and to a device for preventing a collision when driving at least two movers on a drive surface.

BACKGROUND

Planar drive systems may, inter alia, be used in automation technology, in particular in manufacturing technology, handling technology and process engineering. With planar drive systems, a movable element, referred to as a mover, of a system of a machine may be moved or positioned in at least two linearly independent directions. Planar drive systems may comprise a permanently energized electromagnetic planar motor with a planar stator and a rotor, i.e. the 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 arrangement. The present invention relates in particular to embodiments of planar drive devices 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 drive surface.

EP 3 096 144 A1 discloses an automatic laboratory system, wherein sample carriers are provided which carry samples. Priorities are assigned to the samples. The sample carriers are moved to a processing station according to the priority of the samples.

SUMMARY

The invention provides an improved device and an improved method for preventing a collision when driving at least two movers on a drive surface.

According to one aspect, a device prevents a collision when driving at least two movers on a driving surface, each mover comprising at least a second magnetic field generator, the device comprising a plurality of sectors, the sectors comprising magnetic field generators for generating magnetic fields, wherein the sectors form the drive surface, wherein the sectors are connected to at least one control unit, wherein the control unit is embodied to carry out a path planning for the at least two movers, wherein the at least two movers are assigned a priority, the control unit being embodied to take account of the priorities of the movers in the path planning of the travel paths of the movers in such a way that a travel path of a mover with a higher priority takes precedence over a travel path of a mover with a lower priority, so that a collision of the movers is prevented, the control unit being embodied to actuate the magnetic field generators with current in such a way that the movers may be moved over the drive surface along the determined travel paths.

According to another aspect, a method prevents a collision while determining travel paths for at least two movers on a drive surface, each mover having at least a second magnetic field generator, wherein the device comprises a plurality of sectors, the sectors comprising magnetic field generators for generating magnetic fields, the sectors forming the drive surface, wherein path planning is performed for at least two movers, at least the two movers being assigned a priority, the priorities of the movers being taken into account in the path planning of the travel paths of the movers in such a manner that a travel path of a mover with a higher priority takes precedence over a travel path of a mover with a lower priority, so that a collision of the movers is prevented.

According to another aspect, a device prevents a collision when driving a plurality of movers on a driving surface, each mover comprising at least a magnetic field generator, the device comprising a plurality of sectors, the sectors comprising magnetic field generators for generating magnetic fields, wherein the sectors form the drive surface, wherein the sectors are connected to at least one control unit, wherein the control unit is embodied to carry out a path planning for each mover, wherein each mover is assigned a priority, the control unit being embodied to take account of the priorities of the movers in the path planning of the travel paths of the movers in such a way that a travel path of a mover with a higher priority takes precedence over a travel path of a mover with a lower priority, so that a collision of the movers is prevented, the control unit being embodied to actuate the magnetic field generators of the sectors with current in such a way that the movers may be moved over the drive surface along the determined travel paths, wherein the control unit is embodied during path planning of a travel path for a mover to only take into account the travel paths of the further movers that have a higher priority than the mover for which the travel path is being planned, and to plan the travel path of the mover in such a way that the travel path of the mover does not lead to a collision with the further movers having the higher priority.

EXAMPLES

A device for preventing a collision when driving at least two movers on a driving surface is proposed, each mover comprising at least a second magnetic field generator, the device comprising a plurality of sectors, the sectors comprising magnetic field generators for generating magnetic fields, the sectors forming the driving surface, the sectors being connected to at least one control unit, the control unit being embodied to perform a travel path planning for at least two movers, wherein a priority is at least assigned to the two movers, the control unit being embodied to take into account the priorities of the movers in the planning of the travel paths of the movers in such a way a travel path of a mover with a higher priority has priority over a travel path of a mover with a lower priority, so that a collision of the movers is prevented, wherein the control unit is embodied to actuate the magnetic field generators with current in such a way that the movers may be moved over the drive surface along the determined travel paths. This makes it easy to determine a right of way for the mover with the higher priority.

In an embodiment, a first mover has a higher priority than a second mover, wherein the control unit is embodied to disregard the second mover when planning a travel path for the first mover. Thus, a simple method for considering the priorities of the movers is provided. Thus, computing time may be saved when calculating the first travel path for the first mover.

In another embodiment, the control unit is embodied during path planning to plan a second travel path for the second mover in such a way that the second travel path does not lead to a collision with the first travel path. Thus, the higher priority of the first mover is taken into account in a simple manner and a collision is prevented. For example, the second travel path may be planned at a distance from the first travel path. In addition, a crossing between the first and second travel paths may be prevented. In addition, when the paths of the two travel paths intersect, the times at which the movers pass the intersection of the paths may be offset so that no collision of the movers occurs.

Thus, the first mover is considered as a dynamic obstacle if the first mover has a higher priority than the second mover. In this way, the second mover's travel path is planned in such a way that the second mover avoids the first mover.

In an embodiment, a third mover is provided, the third mover having a lower priority than the second mover, the control unit being embodied to disregard the third mover in the path planning of the first travel path for the first mover, wherein the control unit is embodied in order not to take the third mover into account in the path planning of the second travel path for the second mover, the control unit being embodied during planning a third travel path for the third mover to plan the third travel path in such a way that the third travel path does not lead to a collision with the first and the second travel path. In this way, the priorities for more than two movers are also taken into account during path planning. Of course, more than three movers may also be provided with priorities, the travel paths of which are taken into account according to the priorities.

In another embodiment, the priority of a mover depends on an operating state or property of the mover. Thus, flexible and optimal path planning may be achieved.

In a further embodiment, the priority of a mover depends on a speed of the mover, with the priority increasing with the amount of speed. Faster movers are more difficult to brake. In addition, a higher speed results in larger radial forces during cornering. In addition, the reaction distance is longer for faster movers. Thus, it is advantageous to give higher speeds a higher priority.

In an embodiment, the smaller a distance between the mover and a target point, the higher the priority of the mover. In this way, it is achieved that a mover does not stop short of the target point. A target point may be a predetermined station at which a load is picked up or delivered. In addition, the target point may also be a processing station at which processing of the load takes place.

In an embodiment, the greater a minimum possible curve radius of a mover, the higher the priority of the mover. In the case of large minimum curve radii, the possibility of changing the travel path significantly is worse than in the case of a small minimum curve radius. Thus, it is advantageous to assign a higher priority to the more inert movers.

In another embodiment, the priority of a mover depends on a weight of the mover, in particular on a load of the mover, wherein in particular the more the weight of the mover with load, the higher the priority. The mass of the mover with load influences the possibility of changing the travel path. The higher the mass of the mover, the slower a travel path may be changed. In addition, the power consumption when changing a travel path is higher for a mover with a larger mass than for a mover with a smaller mass. In addition, the priority of the mover may depend on the type of load. For example, a liquid load has a higher priority than a solid load. In addition, a toxic load may have a higher priority than a non-toxic load.

In a further embodiment, the smaller a maximum acceleration of a mover is, the higher is the priority of the mover. The smaller the maximum acceleration is, the slower is the reaction time for changing a travel path.

In another embodiment, the priority of a mover depends on an operational state or a characteristic of a sector on which the mover is located. This allows conditions of the sectors to be taken into account in order to make an optimal selection for priority.

In an embodiment, the priority of the mover depends on a temperature of the sector on which the mover is located, with the priority increasing with increasing temperature. It may be advantageous to prevent overheating of the sectors. Thus, it is advantageous to prevent supplying power which would be required to change the path of the mover to sectors where temperatures are high.

In an embodiment, the priority of the mover depends on a power consumption of the sector. It may be advantageous to limit the power consumption of a sector to a predefinable value, e.g. to prevent overheating of the sectors.

In another embodiment, each mover is assigned an individual identifier, with the priority being determined on the basis of the mover identifier. In this way, a ranking of the priorities of the movers is unambiguously defined in a simple manner.

A method for preventing a collision when determining travel paths for at least two movers on a drive surface is proposed, each mover comprising at least a second magnetic field generator, the device comprising a plurality of sectors, the sectors comprising magnetic field generators for generating magnetic fields, the sectors forming the drive surface, wherein path planning is performed for at least two movers, wherein a priority is assigned to at least the two movers, wherein the priorities of the movers are taken into account in the path planning of the travel paths of the movers in such a way that a travel path of a mover with a higher priority has priority over a travel path of a mover with a lower priority, so that a collision of the movers is prevented.

In an embodiment, the magnetic field generators of the sectors are actuated with current in such a way that the movers are moved over the drive surface along the determined travel paths.

In another embodiment, a first mover has a higher priority than a second mover, and the second mover is not taken into account when planning a travel path for the first mover.

In another embodiment, when a second travel path for the second mover is planned, the second travel path is planned such that the second travel path does not result in a collision with the first travel path.

In an embodiment, a third mover is provided, wherein the third mover has a lower priority than the second mover, wherein the third mover is not taken into account in the path planning of the first travel path for the first mover, wherein the third mover is not taken into account in the path planning of the second travel path for the second mover, wherein the third travel path is planned in the path planning of a third travel path for the third mover in such a way that the third travel path does not lead to a collision with the first and the second travel path.

In another embodiment, the priority of the mover depends on an operational state or property of the mover.

In a further embodiment, the priority of a mover depends on a speed of the mover, with the priority increasing with increasing speed, and/or with the priority of the mover increasing with a decrease in distance to a target point of the mover, and/or with the priority of a mover being the higher, the larger a minimum possible curve radius of the mover is, and/or wherein the priority of a mover depends on a weight of the mover, in particular on a load of the mover, wherein the priority is the higher, the higher the weight of the mover with the load is, and/or wherein the priority of the mover is the higher, the smaller a maximum possible acceleration of the mover is.

In an embodiment, the priority of a mover depends on an operational state or property of a sector on which the mover is located.

In an embodiment, the priority of the mover depends on a temperature of the sector on which the mover is located, wherein the priority increases with the height of the temperature, and/or wherein the priority of the mover depends on a power consumption of the sector.

A control unit is proposed which is embodied to carry out one of the described methods.

A computer program is proposed with instructions that, when run on a computer, carry out one of the described methods.

DETAILED DESCRIPTION

The present invention relates to further developments of the planar drive systems disclosed in the publications WO 2013/059934 A1, WO 2015/017933 A1, WO 2015/179962 A1, WO 2015/184553 A1, WO 2015/188281 A1 and WO 2017/004716 A1. The disclosure content of the aforementioned publications is made the additional subject matter of the present description in its entirety by reference.

Furthermore, the invention relates to further developments of the planar drive systems disclosed in German patent applications 10 2017 131 304.4, 10 2017 131 314.1, and 10 2017 131 321.4, filed with the German Patent and Trademark Office on 27 Dec. 2017. The disclosure content of the German patent applications 10 2017 131 304.4, 10 2017 131 314.1, and 10 2017 131 321.4 is made the additional subject matter of the present description in its entirety by reference.

FIG.1shows a device for driving at least one mover200on a drive surface in the form of a planar drive system1comprising a stator module10and a rotor formed by the mover200.

The stator module10includes a module housing19and a stator assembly100. The stator module10has a top side8and a bottom side9opposite the top side8. The stator assembly100is arranged in a vertical direction15oriented from the bottom side9to the top side8above the module housing19and at the top side8of the stator module10. The stator assembly100is formed as a planar stator and has a flat, i.e. planar, stator surface11on the upper side8of the stator module10. At the same time, the stator surface11forms a surface of the stator module10.

The stator surface11is oriented perpendicular to a vertical direction15and extends across the entire top surface8of the stator assembly100and the stator module10along directions12and14. The stator assembly100includes at least one conductor strip125on the stator surface11, to which a drive current may be applied. As shown, the stator assembly100may include a plurality of the conductor strips125on the stator surface11. A drive current may be applied to each of the conductor strips125by a control unit506. With the drive currents in the conductor strips125, a magnetic field may be generated that drives the mover200in interaction with drive magnets of the mover200. The mover200and the stator assembly100with the current-carrying conductor strips125form an electromagnetic planar motor. The conductor strips125form coil conductors of the stator assembly100and may also be referred to as coil conductors or as magnetic field generators.

During operation, the mover200is movably arranged above the stator surface11of the stator module10and, when operated, may be driven in a first direction12as well as in a second direction14. The first direction12and the second direction14are linearly independent. In particular, the first direction12and the second direction14may be oriented perpendicularly with regard to each other, as shown inFIG.1. The first direction12and the second direction14are each oriented in parallel to the stator surface11and perpendicular to the vertical direction15. By driving the mover200in both the first direction12and the second direction14, the mover200may be driven in any direction above the stator surface11. In operation, the mover200may be held floating above the stator surface11, e.g. by magnetic interaction between the drive magnets and suitable drive currents in the conductor strips125. In addition to driving the mover200in the first and/or second directions12,14, it is also possible to drive it in the third, vertical direction15. Furthermore, the mover200may also be rotated about its axis. The conductor strips represent conductor paths.

The stator surface11is rectangular in shape. In particular, the stator surface11may be square in shape, as shown. The stator surface11is limited by four respective straight outer edges30. In each case, two mutually opposite outer edges30are oriented in parallel to the first direction12and two mutually opposite further outer edges30are oriented in parallel to the second direction14.

An extension of the stator assembly100in the vertical direction15is smaller than an extension of the stator assembly100in the first and second directions12,14. Therefore, the stator assembly100forms a flat cuboid extending in the first and second directions12,14or a plate extending in the first and second directions12,14.

Further components may be arranged at the module housing19or at the stator module10on the bottom side9of the stator module10or on the bottom side of the module housing19. These further components extend at most to the outer edges30of the stator assembly100in the first direction12or in the second direction14, so that the further components do not project beyond the outer edges30of the stator assembly100in the first or the second direction12,14.

Connections for connecting the stator module10to a plurality of connecting lines18are arranged on the bottom side of the module housing19. The connecting lines18may e.g. comprise an input line of a data network, an output line of the data network, and a power supply line for supplying electrical power to the stator module10. In addition, a control unit506may be connected to a connecting line18. In particular, electrical power may be supplied to the stator module10via the power supply line to generate the drive currents. Via the data network, the stator module10may be connected to a control unit of the planar drive system, wherein the control unit of the planar drive system may be the control unit506. With the data network, for example, control data for controlling the mover200or for controlling the targeted application of suitable drive currents to the conductor strips may be exchanged with the control unit506.

In the first direction12, the stator surface11may have an extension of between 100 mm and 500 mm, in particular between 120 mm and 350 mm, in particular of 240 mm. In the second direction12, the stator surface11may have an extension of between 100 mm and 500 mm, in particular of between 120 mm and 350 mm, in particular of 240 mm. In the vertical direction15, the stator module10may have an extension of between 10 mm and 100 mm, in particular of between 15 mm and 60 mm, in particular of 30 mm. In the vertical direction15, the module housing19may have an extension of between 8 mm and 80 mm, in particular of between 13 mm and 55 mm, in particular of 26.6 mm. The module housing19may have the same extension in the first and/or second direction12,14as the stator surface11.

Multiple specimens of the stator module10may be arranged adjacent to each other in such a way that the outer edges30of adjacent stator modules10adjoin on one another and the stator surfaces11of the stator modules10form a continuous drive surface over which the mover200may be moved without interruption, as shown inFIG.2. Since the side surfaces of the stator module10are flush with the stator surface11at the outer edges30, the stator surfaces11of two adjacent stator modules10may be arranged almost seamlessly adjoining each other by arranging the stator modules10with adjoining side surfaces of the stator assemblies100or adjoining outer edges30of the stator surfaces11.

Adjacent stator modules10are each arranged adjacent to each other such that the outer edges30of the stator surfaces11of adjacent stator modules10adjoin on one another. As a result, the stator surfaces11of the stator modules10form a continuous, planar drive surface for the mover200. The mover200may be moved seamlessly from the stator surface11of one of the stator modules10onto or over the stator surface11of the adjacent stator module10. Control signals and/or power may be supplied to each of the stator modules10via respective associated connecting lines18. Alternative embodiments of the stator modules10may also include electrical connecting elements by which control signals and/or electrical power may be transmitted from one stator module10to the adjacent stator module10. Such connecting elements may e.g. be arranged on the side surfaces of the stator modules10. The connecting elements may be embodied as connectors or as contact surfaces that may be arranged adjoining one another.

In alternative embodiments, the stator modules10may also be connected to a central power supply device and/or a central control unit in a star configuration, each via their own connecting lines.

FIG.3shows the rotor, i.e. the mover200, in a view from below onto a bottom side of the mover200. The mover200comprises a magnet arrangement201on the bottom side. The magnet arrangement201is rectangular, in particular square, in shape and comprises a plurality of magnets. The bottom side of the mover200is flat or planar, in particular in the area of the magnets of the magnet arrangement201. In operation, the bottom side of the mover200comprising the magnet arrangement201is essentially oriented in parallel to the stator surface11and is arranged facing the stator surface11.

The magnet arrangement201includes a first magnet unit210, a second magnet unit220, a third magnet unit230, and a fourth magnet unit240. The first magnet unit210and the third magnet unit230each comprise drive magnets211extending in an elongated manner in a first rotor direction206and arranged side by side along a second rotor direction208oriented perpendicularly with regard to the first rotor direction206. In particular, the first and third magnet units210,230may each have three drive magnets211. The second magnet unit220and the fourth magnet unit240each have further drive magnets221arranged side by side in the first rotor direction206and extending in an elongated manner along the second rotor direction208. In operation, the first and third magnet units210,230serve to drive the mover200in the second rotor direction208, and the second and fourth magnet units220,240serve to drive the mover200in the first rotor direction206. The drive magnets211of the first and third magnet units210,230and the further drive magnets221of the second and fourth magnet units220,240are respectively magnetized perpendicular with regard to the first and second rotor directions206,208.

The drive magnets211and/or further drive magnets221represent second magnetic field generators250. The second magnetic field generators250may also have other materials, functional principles and/or shapes.

FIG.4shows the stator module10of the planar drive system1in a perspective view without the mover200. The stator assembly100of the stator module10comprises a first stator sector110, a second stator sector112, a third stator sector113, and a fourth stator sector114. The stator sectors110,112,113,114each in turn comprise a portion of conductor strips125disposed on the stator surface11of the stator assembly100. Each of the conductor strips125on the stator surface11is arranged entirely within one of the stator sectors110,112,113,114. The stator sectors110,112,113,114are rectangular in shape. In particular, the stator sectors110,112,113,114may be square in shape such that an extension of the stator sectors110,112,113,114in the first direction12corresponds to an extension of the stator sectors110,112,113,114in the second direction14.

The stator sectors110,112,113,114each comprise a quarter of the area, i.e., a quadrant, of the stator assembly100.

Within the stator sectors110,112,113,114, the conductor strips125are arranged in a plurality of stator layers or stator planes arranged on top of one another, each of the stator layers comprising only conductor strips125either essentially extending in an elongated manner along either the first direction12or essentially along the second direction14. Apart from the extension of the conductor strips125, and unless differences are described in the following, the stator sectors110,112,113,114are formed identically on the different stator layers. In the stator assembly100of the stator module10shown inFIG.4, the stator layer on the stator surface11comprises only conductor strips125, which extend in an elongated manner along the first direction12and are arranged side by side and adjoining one another along the second direction14.

The stator layer visible inFIG.4at the stator surface11forms a first stator layer of the stator assembly100. In the vertical direction15below the first stator layer, the stator assembly100comprises at least one more second stator layer.

FIG.5shows a schematic perspective depiction of an exploded view of the stator assembly100with the individual stator layers.

In the vertical direction15, the stator assembly100comprises a second stator layer105below the first stator layer104arranged on the stator surface11, a third stator layer106below the second stator layer105, and a fourth stator layer107below the third stator layer106. Unless differences are described in the following, the second, third, and fourth stator layers105,106,107are formed like the first stator layer104on the stator surface11of the stator assembly100shown inFIG.4.

In the third stator layer106, as in the first stator layer104, the first to fourth stator sectors110,112,113,114comprise conductor strips125extending in an elongated manner along the first direction12and arranged side by side and adjoining one another in the second direction14. In the second stator layer105and in the fourth stator layer107, the first to fourth stator sectors110,112,113,114comprise further conductor strips126. Unless differences are described in the following, the further conductor strips126are formed like the conductor strips125in the first stator layer104and in the third stator layer106. Unlike the conductor strips125of the first and third stator layers104,106, the further conductor strips126of the second and fourth stator layers105,107extend in an elongated manner along the second direction14and are arranged side by side and adjoining one another in the first direction12.

In the first and third stator layers104,106, the first to fourth stator sectors110,112,113,114exclusively comprise the conductor strips125extending in an elongated manner along the first direction12and not additionally the further conductor strips126extending in an elongated manner along the second direction14. Similarly, in the second and fourth stator layers105,107, the first to fourth stator sectors110,112,113,114exclusively comprise the further conductor strips126extending in an elongated manner along the second direction14and not additionally the conductor strips125extending in an elongated manner along the first direction12.

The first to fourth stator sectors110,112,113,114each have the same dimensions in all first to fourth stator layers104,105,106,107. In particular, the first to fourth stator sectors110,112,113,114each have the same dimensions in all first to fourth stator layers104,105,106,107in the first direction12and in the second direction14.

The conductor strips125and the further conductor strips126of first to fourth stator layers104,105,106,107arranged on top of one another are each embodied to be electrically insulated from one another. For example, the first to fourth stator layers104,105,106,107may each be formed as mutually insulated conductor path layers of a multi-layer printed circuit board.

The first to fourth stator sectors110,112,113,114are embodied to be energizable independently from one another. In particular, the conductor strips125and the further conductor strips126of the first to fourth stator sectors110,112,113,114are embodied on the stator assembly100to be electrically insulated from one another.

While the conductor strips125and the further conductor strips126of the individual first to fourth stator sectors110,112,113,114on the stator assembly100are each embodied to be electrically isolated from the conductor strips125and the further conductor strips126of the remaining first to fourth stator sectors110,112,113,114, the conductor strips125and further conductor strips126within the individual first to fourth stator sectors110,112,113,114may each be electrically conductively connected to one another. In particular, within each of the first to fourth stator sectors110,112,113,114, stacked conductor strips125of the first stator layer104and the third stator layer106may be electroconductively connected to one another. For example, respective conductor strips125of the first to fourth stator sectors110,112,113,114arranged on top of one another may be connected in series. Similarly, within each of the first to fourth stator sectors110,112,113,114, further conductor strips126of the second stator layer105and the fourth stator layer107may be electrically conductively interconnected. For example, further conductor strips126of the first to fourth stator sectors110,112,113,114arranged on top of one another may be connected in series.

Alternative embodiments of the stator assembly100may comprise further stator layers arranged one below the other between the second and third stator layers105,106in the vertical direction15. In this context, the stator assembly100may in the vertical direction15in each case comprise alternating stator layers having conductor strips125essentially extending in an elongated manner along the first direction12and stator layers with further conductor strips126essentially extending in an elongated manner along the second direction14. In an alternative embodiment, the stator assembly100may in the vertical direction15comprise respective stator layers having conductor strips125essentially extending in an elongated manner along the first direction12and stator layers having further conductor strips126essentially extending in an elongated manner along the second direction14, wherein the sum of the stator layers having conductor strips125essentially extending in an elongated manner along the first direction12and the sum of the stator layers having further conductor strips126essentially extending in an elongated manner along the second direction14have an equal mean distance from the stator surface11. Furthermore, in alternative embodiments of the stator assembly100, further stator layers with conductor strips125extending in an elongated manner along the first direction12or with further conductor strips126extending in an elongated manner along the second direction14may be arranged between the first and the second stator layers104,105and/or between the third and the fourth stator layers106,107.

The conductor strips125,126of the first through fourth stator sectors110,112,113,114are respectively combined into stator segments within the first through fourth stator layers104,105,106,107.

FIG.6shows a schematic depiction of the first to fourth stator layers104,105,106,107of the first stator sector110with the individual stator segments.

The conductor strips125and further conductor strips126of the first stator sector110are combined into stator segments120,121within each of the first to fourth stator layers104,105,106,107. In each of the first to fourth stator layers104,105,106,107, the first stator sector110comprises three stator segments120,121arranged side by side and adjoining one another. Each of the stator segments120,121comprises six conductor strips125or further conductor strips126arranged side by side. The first stator sector110comprises three first stator segments120in each of the first and third stator layers104,106and three second stator segments121in each of the second and fourth stator layers105,107. The first stator segments120each comprise six adjacent ones of the conductor strips125arranged side by side along the second direction14and extending in an elongated manner along the first direction12, and the second stator segments121each comprise six adjacent ones of the further conductor strips126arranged side-by-side along the first direction12and extending in an elongated manner along the second direction14.

Thus, in the first stator layer104and in the third stator layer106, the first stator sector110of the stator assembly100exclusively comprises conductor strips125in an elongated manner along the first direction12, and, in the second stator layer105and in the fourth stator layer107, exclusively further conductor strips126in an elongated manner along the second direction14.

The first and second stator segments120,121have identical dimensions except for their orientation. In particular, the dimensions of the first stator segments120in the first direction12correspond to the dimensions of the second stator segments121in the second direction14, and the dimensions of the first stator segments120in the second direction14correspond to the dimensions of the second stator segments121in the first direction12.

The stator segments120,121are arranged on top of one another in such a way that each of the first stator segments120of the first and third stator layers104,106of the first stator sector110extends in the first direction12over the three second stator segments121of the second and fourth stator layers105,107of the first stator sector110that are arranged side by side to one another in the first direction12. Further, the second stator segments121of the second and fourth stator layers105,107of the first stator sector110extend in the second direction14over all of the first stator segments120of the first and third stator layers104,106of the first stator sector110that are arranged side by side to one another in the second direction14.

The arrangement of the conductor strips125and further conductor strips126in the first to fourth stator layers104,105,106,107of the second stator sector112, the third stator sector113and the fourth stator sector114corresponds to the arrangement of the conductor strips125and further conductor strips126in the first to fourth stator layers104,105,106,107of the first stator sector110shown inFIG.6.

When operating the planar drive system1, the mover200may be aligned over the stator assembly100such that the first rotor direction206is oriented along the first direction12and the second rotor direction208is oriented along the second direction14. In operation, the first magnet unit210and the third magnet unit230may interact with the magnetic field generated by the conductor strips125of the first stator segments120to drive the mover200along the second direction14. The second magnet unit220and the fourth magnet unit240may in operation interact with the magnetic field generated by the further conductor strips126of the second stator segments121to drive the mover200along the first direction12.

Alternatively, other than shown inFIG.6, the mover200may be oriented such that the first rotor direction206is oriented along the second direction14and the second rotor direction208is oriented along the first direction12. In this case, the first and third magnetic units210,230interact with the magnetic field of the second stator segments121to drive the mover200in the first direction12and the second and fourth magnetic units220,240interact with the magnetic field of the first stator segments120to drive the mover200in the second direction14.

The conductor strips125or further conductor strips126of the individual first or second stator segments120,121may each be supplied with the drive currents independently of the conductor strips125or further conductor strips126of the remaining first or second stator segments120,121. In particular, the drive currents in one of the first or second stator segments120,121do not necessarily depend on drive currents in one of the other first or second stator segments120,121. Furthermore, the conductor strips125or further conductor strips126of one of the first or second stator segments120,121may be energized with drive currents while the conductor strips125or further conductor strips126of another, for example an adjacent, first or second stator segment120,121are without current. The conductor strips125or further conductor strips126of the individual first or second stator segments120,121are electrically isolated from the conductor strips125or further conductor strips126of the remaining first or second stator segments120,121on the stator assembly100. The conductor strips125or further conductor strips126of different first or second stator segments120,121may e.g. be supplied with the drive currents from respective separate power modules or from separate power generation units or output stages of a power module of the stator module10.

The conductor strips125or further conductor strips126in the individual first to fourth stator sectors110,112,113,114may each be interconnected to form multi-phase systems with a shared neutral point. The neutral point may be formed on the stator assembly100. In particular, the conductor strips125or further conductor strips126may be interconnected to form three-phase systems with a shared neutral point. The three-phase systems may each comprise six adjacent conductor strips125or six adjacent further conductor strips126. The number of adjacent conductor strips125or further conductor strips126in one of the three-phase systems may also be three, twelve or another multiple of three in each case.

The multiphase systems may be contactable on the stator assembly100in such a way that each of the multiphase systems may be supplied with a drive current independently of the other multiphase systems. Alternatively, two or more of the multiphase systems may each be connected to one another on the stator assembly100such that a common drive current is jointly applied to each of the connected multiphase systems. For example, the connected multiphase systems on the stator assembly100may be connected in series or in parallel.

If the conductor strips125or further conductor strips126are interconnected to form multiphase systems, fewer contacts are required for energizing the conductor strips125or further conductor strips126than when separately energizing the individual conductor strips125or further conductor strips126. This reduces the amount of hardware required for energizing the conductor strips125or further conductor strips126, in particular the number of power-generating units required for energization.

The first to fourth stator sectors110,112,113,114may each include eighteen conductor strips125or further conductor strips126in each of the first through fourth stator layers104,105,106,107, as shown inFIGS.4and5. Six adjacent conductor strips125or further conductor strips126may each be interconnected to form a three-phase system, and the first to fourth stator sectors110,112,113,114may each comprise three three-phase systems side by side in the first direction12and three three-phase systems arranged side by side in the second direction14. In this regard, conductor strips125or further conductor strips126, which are essentially extended in the same direction12,14and are positioned on top of one another in the first to fourth stator layers104,105,106,107, may be connected in series to form a common three-phase system. The conductor strips125or further conductor strips126may thereby be connected in such a way that conductor strips125or further conductor strips126positioned on top of one another in the vertical direction15are each supplied with the same drive current. The three-phase systems thus have three phases which are interconnected through conductor strips125or further conductor strips126positioned on top of one another in the first to fourth stator layers104,105,106,107.

For example, in each of the individual first to fourth stator layers104,105,106,107, all conductor strips125or further conductor strips126positioned on top of one another and aligned in parallel may be connected in series. In particular, the conductor strips125of three-phase systems positioned on top of one another in the first stator layer104and in the third stator layer106, and the further conductor strips126of three-phase systems positioned on top of one another in the second stator layer105and in the fourth stator layer107may each be connected in series to form a shared three-phase system. Thereby, all conductor strips125or further conductor strips126of the first and third stator layers104,106and of the second and fourth stator layers105,107which are positioned on top of one another in the vertical direction15and oriented in parallel may be connected in series.

In particular, in the stator assembly100within the individual stator segments120, the conductor strips125extending in an elongated manner along the first direction12are each connected to form multiphase systems with a shared neutral point. In this case, the individual multiphase systems of different stator segments120may each be energized independently of one another. Similarly, all further conductor strips126of the individual further stator segments121are each connected to form further multiphase systems. The individual further multiphase systems of the further stator segments121may each be supplied with current independently of one another and independently of the multiphase systems of the stator segments120. In particular, the conductor strips125of the stator segments120and the further conductor strips126of the further stator segments121are each connected to form three-phase systems. A three-phase drive current may be applied to each of the conductor strips125and the further conductor strips126. The drive currents comprise a first phase U, a second phase V and a third phase W, each having a phase offset of 120° with regard to one another.

The conductor strips125are spatially offset in the second direction14by in each case one third of the effective wavelength of the drive magnets211of the first and third magnet units210,230interacting with the conductor strips125. The further conductor strips126are arranged spatially offset in the first direction12by in each case one third of the effective further wavelength of the further drive magnets221of the second and fourth magnet units220,240interacting with the further conductor strips126.

The conductor strips125and the further conductor strips126represent magnetic field generators127. The magnetic field generators127may also comprise other materials, functional principles and/or forms.

The mover represents the movable element, i.e. the rotor of the device and comprises elements for generating a magnetic field, in particular magnets or permanent magnets, referred to as second magnetic field generator. The magnetic field of the mover, together with the variable magnetic field of the stator assembly generated by the magnetic field generator127, ensures that the mover is moved over the stator assembly so that, in particular, an air gap is formed between the stator assembly and the mover.

FIG.7shows a schematic view of a section of a drive surface510in a top view. The drive surface510may be formed by a plurality of stator modules10of the planar drive system described inFIGS.1to6. However, other embodiments of planar drive systems that use magnetic fields to move a mover200on a drive surface510may be used, as well. Four sectors501are shown, wherein each sector501may be formed by a stator module10ofFIGS.1to6. In the embodiment example, the four sectors501have the shape of squares. Depending on the chosen embodiment, the sectors501may also have other shapes, such as rectangles or triangles, etc. For example, a sector501may have a size in the range of 150 mm×150 mm up to 240 mm×240 mm. Depending on the chosen embodiment, a sector501may also have other sizes. In addition, sectors501may also have different sizes.

In addition, a first mover200, a second mover513and a third mover514are arranged on the drive surface510. Unless a distinction is made in the following between the individual first, second or third movers200,513,514, the statements made for the first mover200, the second mover513and/or the third mover514apply in an analogous manner. Accordingly, at the corresponding locations in the following, reference will only be made to movers having the shared reference numeral5. The first mover200e.g. embodied as a rotor, as described inFIGS.1to3. The first mover200may have a square, round or rectangular shape or other shapes. For example, the first mover200may have a size in the range of 100 mm×100 mm up to 200 mm×200 mm. The first mover200may have a thickness in the range of 8 mm to 20 mm. The drive surface510, i.e. the stator module10, and the first mover200may be embodied to move the first mover200at a speed of e.g. 1 m/s to 6 m/s. The drive surface510, i.e. the stator module10, and the first mover200may be embodied to move the first mover200with an acceleration of up to 30 m/s2or more. Furthermore, the first mover200may be embodied to carry a load of up to 1.5 kg or more. In addition, the first mover200may be embodied to move at a distance from the drive surface510of up to 6 mm or more. The second mover513and/or the third mover514may be embodied identically to the first mover200.

Furthermore, a static obstacle509is additionally arranged on the drive surface510. The control unit506is connected to a data memory512and is directly or indirectly connected to the magnetic field generators of the sectors501. In addition, the control unit506is connected to sensors560of the drive surface510, which e.g. detect a current position of the movers5, a current speed of the movers5, a current acceleration of the movers5and/or a current direction of movement of the movers5and/or a load of the movers with load material5and transmit them to the control unit506.

In addition, the control unit506may have stored in the data memory512information about planned or calculated positions of the movers5, calculated values for speeds of the movers5, calculated values for accelerations of the movers5, and/or calculated values for directions of movement of the movers5, and/or a loading condition of the movers5, and/or a weight of the load of the movers5, and/or a weight of the mover5, and/or values for maximum accelerations of the movers5.

Furthermore, a priority may be stored in the data memory512for each mover5. The priority of a mover5may e.g. depend on an operational state or characteristic of the mover5. For example, the priority of a mover5may depend on a speed of the mover5, with the priority increasing as the speed increases. Further, the priority of the mover5may increase as a distance to a target point508,516of the mover5decreases. Furthermore, the priority of a mover5may be the higher, the larger a minimum possible radius of curvature of the mover5is. Furthermore, the priority of a mover5may depend on a weight of the mover5, in particular on a loading of the mover5with a load, the priority being the higher, the higher the weight of the load is. In addition, the priority of the mover5may depend on the type of load. For example, a mover5with a liquid load may have a higher priority than a mover5with a solid load. Furthermore, the smaller a maximum acceleration of the mover5is, the higher the priority of the mover5may be.

Further, the priority of a mover5may depend on an operational state or a property of a sector501on which the mover5is located. For example, the priority of the mover5may depend on a temperature of the sector501on which the mover5is located, with the priority increasing as the temperature increases. In addition, the priority of the mover5may depend on a power consumption of the sector501. Further, the properties of the sector may be how fast a magnetic field may be established and/or what magnetic field strength may be established by the sector501. Moreover, each mover5may be assigned a fixed priority that e.g. depends on an individual identifier, e.g. a number, of the mover5. The identifier is e.g. stored in the data memory512. Each identifier exists only once. Thus, the identifiers may be used to easily define a clear ranking of the priorities of the movers5.

The priority of a mover5may be determined by the control unit506according to predetermined rules. The rules may be stored in the data memory512. Moreover, the priority of a mover5or the rule for determining the priority of a mover5may be changed by an operator by a corresponding input to the control unit506.

The control unit506is embodied to determine travel paths for the movers5from the respective starting points of the movers5to the respective target points of the movers5depending on predefined boundary conditions. For this purpose, the control unit506first checks the priorities of the movers5. The priorities of the movers5may be permanently stored in the data memory512or may be determined currently prior to determining the travel paths depending on further parameters.

In the following, only three movers200,513,514are considered. The criteria for determining priorities are chosen such that the priority relation of the movers200,513,514is transitive and thus an unambiguous ranking of priorities is determined for multiple movers200,513,514. Consequently, if a first mover200has a higher priority than a second mover513, and the second mover513has a higher priority than a third mover514, the first mover200thus also has a higher priority than the third mover514.

In an embodiment, the control unit506first determines a first mover200with the highest priority. Then, the control unit506determines the first travel path503for the first mover200from the first starting point507of the first mover200to the first target point508of the first mover200depending on predetermined boundary conditions. In this context, the movers5having a lower priority and their possible travel paths are not taken into account in the path planning of the first mover200. The travel path comprises a path and information on when the first mover200should be at which position of the path.

Then, the control unit506determines a second mover513having the second highest priority. Then, the control unit506determines a second travel path from the second starting point515of the second mover513to the second target point516depending on predetermined boundary conditions. In this case, the first mover200which has a higher priority than the second mover513, and the first travel path503are taken into account in such a way that the second mover513avoids the first mover200and no collision occurs as a result. When planning the travel path for the second travel path, other movers5,514that have a lower priority than the second mover513and their travel paths are not taken into account. In an analogous manner, the travel paths are determined for all movers5. The control unit506performs dynamic planning and controls the corresponding magnetic field generators of the sectors501in such a way that the movers5are moved according to the determined travel paths.

In another embodiment, the travel paths of the movers may also be determined as follows:The control unit506determines a first travel path503for the first mover200from a first starting point507to a first target point508depending on predetermined boundary conditions.

In addition, the control unit506determines a second travel path517for the second mover513starting from a second starting point515to a second target point516. The first travel path503comprises a first path and information on when the first mover200should be at which position of the first path. The second travel path517comprises a second path and information on when the second mover513should be at which position of the second path. For a simplified illustration, the first travel path503is indicated as a dotted line with an arrowhead in the direction of the first target point508, which reflects the first path. In addition, for a simplified depiction of the second travel path517, the second travel path517is shown as a dotted line with an arrowhead in the direction of the second target point516, representing the second path.

After the first and second travel paths503,517have been determined by the control unit506or while the first and second travel paths are being determined, the control unit506checks whether there is a risk of collision between the first and second movers200,513. The danger of a collision exists if the first mover200and the second mover513would collide during a departure of the first mover200on the first travel path503and a departure of the second mover513on the second travel path517. If the check shows that no collision is to be expected, the control unit506performs a dynamic planning and controls the corresponding magnetic field generators127of the sectors501in such a way that the first mover200is moved according to the first travel path503and the second mover513is moved according to the second travel path517.

However, if the check reveals that a collision would occur between the first and second movers200,513, the priority of the first mover200is compared to the priority of the second mover513. The first or second mover200,513having the higher priority has priority in planning the travel path503,517, so that the first or second mover200,513with the higher priority maintains the determined travel path503,517. For the first or second mover200,513with the lower priority, the travel path503,517is changed accordingly so that no collision will occur and the target is still reached as far as possible according to the specified boundary conditions. For example, the change of the first or second travel path503,517due to a lower priority may consist of the first or second mover200,513moving more slowly or the first or second mover200,513using a different path and thus preventing a collision between the first and second movers200,513.

If, for example, the first mover200has a higher priority than the second mover513, the second travel path517of the second mover513is changed accordingly so that a collision is prevented. Depending on the chosen embodiment, the priority may in each case be determined by the control unit506according to predetermined rules before the first or second travel paths503,517are determined, or predetermined priorities are read out from the data memory512by the control unit506.

The priorities of the movers5are read from the data memory512by the control unit506or determined as follows:In a simple embodiment of the method, the priorities of the movers5are unambiguously defined and are e.g. determined by the identifiers assigned to the movers5, e.g. as numbers. In this embodiment, e.g. the first or second mover200,513with a smaller number has a higher priority than a first or second mover200,513with a higher number.

In another embodiment, the priorities of the movers5may depend on several parameters and may be determined by the control unit506as follows.

For example, with a focus on preventing high temperatures in sectors501, the priorities of the movers5may be determined as follows:The mover5that is located on a sector501with a higher temperature or on a sector501with a temperature above a predetermined critical temperature has the higher priority. If at least two movers5, i.e. the first mover200, the second mover513and/or the third mover514are located on a sector501with the same high temperature or on a sector501with a temperature above the predetermined critical temperature, it is checked which mover5moves with a higher speed. The mover5with the higher speed has the higher priority. If at least two movers5have an equal current speed, then another parameter may be checked. The further parameter may e.g. be that the mover5having a shorter distance to its target point508,516has the higher priority. If, for example, at least movers5have the same distance to their respective target point508,516, a further parameter may be checked.

For example, the further parameter may be the identifier of the mover5. Thus, the mover5with the smaller identifier has the higher priority. Depending on the chosen embodiment, the mover5with the higher identifier may also have the higher priority.

In a further procedure in which the more inert mover5is prioritized in the path planning, the priority may be determined according to the following procedure: First, it is checked which of the movers5has to drive a larger minimum curve radius. The minimum curve radius depends on the current speed, the current weight of the mover5including the load, and the available force by means of which the magnetic field generators of the sectors501may act on the mover5. The mover5that may drive a smaller curve radius has the lower priority. If at least two movers5are able to drive an equal minimum curve radius, another parameter may be checked.

The other parameter is, for example, the lower possible maximum acceleration. Thus, it is determined that the mover5which may be accelerated with a lower maximum acceleration has the higher priority. The lower possible maximum acceleration may e.g. depend on the type of mover5, the weight of the mover5, the possible maximum magnetic field of the sector501on which the mover5is located, etc. If at least two movers5may be accelerated with the same possible maximum acceleration, another parameter may be checked. The further parameter may be the distance to the respective target point508,516of the respective mover5. For example, the mover5with the shorter distance to the respective target point508,516has the higher priority. If at least two movers5have the same distance to the respective target point508,516, a further parameter may be checked. The further parameter may be the identifier of the mover5. The mover5with the smaller identifier is assigned the higher priority. Depending on the chosen embodiment, the mover5with the larger identifier may also be assigned the higher priority. Thus, an order of priority between the movers5is clearly defined for this method, as well.

Another approach to prioritizing may be to prioritize depending on the type of payload. A possible reason for prioritizing different payloads in a different manner may e.g. be that liquids as payloads are less suitable to be subjected to high accelerations and high lateral forces. Thus, it may be advantageous to give higher priority to movers5with a liquid payload than to solid payloads, so that movers5with liquid payloads may be moved more undisturbed than movers5with solid payloads.

In this context, the mover5with the higher prioritized payload is assigned the higher priority. For example, 512 rankings for the payloads and their priorities are stored in the data memory. For example, a product B may have a higher priority as a payload than a product A. In addition, product A has a higher priority as a payload than another product C. If the check shows that at least two movers5carry an equally highly prioritized payload, a further parameter is checked. The further parameter may be the shorter distance to the target point508,516of the respective mover5. If the distances of the at least two movers5to the target points508,516are identical, a further parameter is checked. The further parameter may lie in the identifier of the movers5. The mover5with the smaller identifier is assigned the higher priority. Depending on the chosen embodiment, the mover5with the larger identifier may also be assigned a higher priority.

Depending on the chosen embodiment, the control unit506may e.g. ignore the travel paths517of other movers5, for example the second mover513or the third mover514, which have a lower priority than the first mover200, when planning the travel path for the first mover200. Thus, the first travel path503of the first mover200does not need to be adjusted because the travel paths of the second and/or third movers513,514do not need to be considered in the travel path planning for the first mover200.

In addition, movers200,513,514having a higher priority may in path planning be considered as dynamic obstacles519. However, in the path planning for the second mover513, the first travel path of the first mover200is then taken into account in such a way that the second travel path517is adapted so that the first mover200may travel unhindered along the first travel path503due to its higher priority. In general, it may be said that the movers5or the travel path plans of the movers5with a higher priority are thus always taken into account in the travel path planning of movers5with a lower priority, and the control unit506selects a travel path503,517for a mover5with a lower priority in order to avoid the other movers5with a higher priority.

Depending on the chosen embodiment, it is possible to switch between different priority setting methods depending on operating states of the sectors501.

Depending on the chosen embodiment, the control unit506when planning the travel path of a mover5only considers priorities of movers5that are in a predetermined fixed environment with regard to the mover5for which the travel path planning is performed. The fixed environment may e.g. be a specified radial distance from the mover5. In addition, the defined environment may be selected in such a way that a collision with other movers5outside the defined environment may be excluded within a predefined time horizon. This saves computational effort for the control unit506. Thus, for a plurality of movers5, the control unit506may comprise different local priority lists for the respective environments of the movers55. Thus, it is not necessary that a global unique priority list is stored for all movers5.

Moreover, depending on the chosen embodiment, the respective path planning for the individual movers5may be repeated at fixed time intervals, i.e. in a predetermined cycle. Moreover, the respective path planning for the different movers5may be executed by different control units506, in particular by different cores of a multi-core system. Due to the unambiguous priorities of the movers5, potential conflicts are unambiguously resolved.

By only considering the movers5that are within a specified environment and/or only the movers5that have a higher priority, path planning for multiple movers5is significantly simplified.

The positions of the movers5, the speeds of the movers5, and/or the accelerations of the movers5may be determined using sensors560associated with the sectors501. For example, the sensors560may be magnetic field sensors, in particular Hall sensors. In addition, the position of the movers5, the speeds of the movers5, and/or the accelerations of the movers5may be estimated based on the actuation of the magnetic field generators127of the sectors501.

After creating the travel paths503,517for the movers5, the control unit506performs dynamic planning and determines by means of which magnetic fields, by means of which magnetic field generators127the movers5must be moved at which times and at which locations in order to maintain the respective determined travel path503,517. Subsequently, the control unit506supplies power to the corresponding magnetic field generators127of the sectors501according to dynamic planning in order to realize the desired travel paths503,517of the movers5.

With the described method, the amount of data that must be taken into account in path planning is significantly reduced. This allows for a better scalability of the system even for a larger number of movers5.

This invention has been described with respect to exemplary embodiments. 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 embodiments that fall within the scope of the claims.