DE102020208411A1 - Method for determining a relative position P and system - Google Patents

Abstract

The method (10) according to the invention for determining a relative position P of a first object (100, 100a, 100b) with respect to at least one reference object (200, 200a, 200b) comprises: - Generating at least three directional magnetic fields with distinguishable modulation frequencies by means of a reference object (200 , 200a, 200b) associated magnetic field generating device (202), wherein the magnetic field generating device (202) comprises at least three emitter coils which alternately have a defined arrangement relative to one another,- detecting magnetic field strengths and modulation frequencies of the magnetic fields by means of a magnetic field detecting device (112, 112a) of the first object ( 100, 100a, 100b), - determining the relative position P of the first object (100, 100a, 100b) with respect to the at least one reference object (200, 200a, 200b) by means of an evaluation device (302) from the detected modulation frequencies directed magnetic fields possible magnetic field strengths. A system comprising a first object, at least one reference object (200, 200a, 200b) and an evaluation device (302) is also proposed, the system being set up to carry out the method (10) according to the invention.

Description

The invention relates to a method for determining a relative position P of a first object in relation to at least one reference object. Furthermore, the invention relates to a system comprising a first object, at least one reference object and an evaluation device, the system being set up to carry out the method according to the invention.

State of the art

The precise position determination of objects, especially of autonomous systems such as drones or robots, is challenging. The essential criteria include a high degree of precision in determining the location, usually in x, y and z coordinates, and the alignment of the object. In addition, costs, size and power consumption of system components play an important role in the implementation of such systems. For example, robot lawn mowers require accuracies of less than 5 cm in an area with a radius of 20 m in order to be able to rely on the installation of a boundary wire as a means of determining position in the future, cf. DE 102017214314 A1 to be able to do without.

Inexpensive satellite-based navigation systems enable positioning accuracies of a few meters to less than 50 cm (ideally with reference signals of less than 2 cm), depending on the environment in which the system is used. The application is limited to outdoor areas. Radar, video or lidar-based positioning systems, which allow position determination by evaluating information captured from the environment, require either expensive sensor systems and/or high demands on computing power within the system.

A comparatively simple alternative to such positioning systems are systems that make it possible to determine a relative position, ie in particular a position and/or an orientation, of an object with respect to a magnetic field transmitter using magnetic fields. Such systems are known, for example, from US 4,737,794 A1 .

Disclosure of Invention

• - Erzeugen zumindest dreier gerichteter Magnetfelder B1, B2, B3 mit unterscheidbaren Modulationsfrequenzen f1, f2, f3 mittels einer dem Referenzgegenstand zugeordneten Magnetfelderzeugungsvorrichtung, wobei die Magnetfelderzeugungsvorrichtung zumindest drei Emitterspulen Tx1, Tx2, Tx3 umfasst, die wechselweise eine definierte Anordnung zueinander aufweisen,
• - Erfassen von Magnetfeldstärken |Bx(P)|, |By(P)|, |Bz(P)| und Modulationsfrequenzen f1, f2, f3 der Magnetfelder B1, B2, B3 mittels einer Magnetfelderfassungsvorrichtung des ersten Gegenstands,
• - Ermitteln der relativen Position P des ersten Gegenstands bezüglich des zumindest einen Referenzgegenstands mittels einer Auswertevorrichtung aus den erfassten, über die erfassten Modulationsfrequenzen f1, f2, f3 den gerichteten Magnetfeldern B1, B2, B3 zuordenbaren Magnetfeldstärken |Bx(P)|, |By(P)|, |Bz(P)|.

In a first aspect of the invention, a method for determining a relative position P of a first object with respect to at least one reference object is proposed. The procedure includes:

• - generating at least three directional magnetic fields B1, B2, B3 with distinguishable modulation frequencies f1, f2, f3 by means of a magnetic field generating device assigned to the reference object, wherein the magnetic field generating device comprises at least three emitter coils Tx1, Tx2, Tx3, which alternately have a defined arrangement in relation to one another,
• - Detection of magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| and modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3 by means of a magnetic field detection device of the first object,
• - Determining the relative position P of the first object with respect to the at least one reference object by means of an evaluation device from the detected magnetic field strengths |Bx(P)|, |By( P)|, |Bz(P)|.

The recorded magnetic field strengths in detailed notation represent magnetic field components |Bx ^1,2,3 (P)|, |By ^1,2,3 (P)|, |Bz ^1,2,3 ( P)| represent.

The relative position P of the first object with respect to the at least one reference object relates to its relative location, for example specified by three coordinates x, y and z with respect to three in particular orthogonal coordinate axes X, Y, Z, and/or its relative alignment, for example specified by three angles of rotation φ, θ, ρ, especially around these three axes X, Y, Z.

The relative position is derived from the detection of magnetic fields B1, B2, B3, which are generated and emitted by a magnetic field generating device. A magnetic field is to be understood in particular as an electromagnetic alternating field, with the proportion of the electrical alternating field not being discussed in this document. The magnetic field generating device serves to generate at least three directional magnetic fields B1, B2, B3, all of which act at every point in space. For this purpose, the magnetic field generating device includes all components required for generating and emitting the magnetic fields, such as a control device, a signal generator, a power supply, etc.

The magnetic fields can, in particular when generated in parallel, overlap in direction and magnetic field strength, so that a three-dimensional magnetic field composed of the at least three magnetic fields B1, B2, B3 is generated at least in an environment of the magnetic field generating device. Alternatively, the magnetic fields can be generated sequentially, so that only one magnetic field B1 or B2 or B3 acts at any point in space at a time. In this way it is possible to achieve a greater range of a position that can be determined with a higher transmission power of each individually emitted magnetic field, while at the same time limiting values in an emission power can be kept low.

The magnetic fields B1, B2, B3 are generated by means of at least three emitter coils Tx1, Tx2, Tx3, which alternately have a defined arrangement with respect to one another. RF coils, for example, are conceivable as emitter coils. In particular, the three emitter coils Tx1, Tx2, Tx3 are mutually orthogonally aligned, so that the magnetic fields B1, B2, B3 generated by the emitter coils Tx1, Tx2, Tx3 are also mutually orthogonally aligned (ie a mutually orthogonally arranged characteristic, for example symmetry, or shape exhibit). Alternatively, other angles between the emitter coils Tx1, Tx2, Tx3 can be chosen. Due to the fixed relationship between the magnetic fields B1, B2, B3, the magnetic fields B1, B2, B3 can be understood as directed, i.e. there is no fundamentally random course of the magnetic fields B1, B2, B3 (apart from the influence of interference fields, see below) . The magnetic fields B1, B2, B3 can be described with magnetic field vectors with respective components in the x, y and z directions, ie |B1 ^xyz |, |B2 ^xyz |, |B3 ^xyz |. In the present method, the magnetic field vector at a given point in space is evaluated separately for the field of the Tx1, Tx2 and Tx3 emitter coil.

In one embodiment of the method for determining a relative position, a transmission level when generating the magnetic fields B1, B2, B3 is dependent on a magnetic field strength |Bx(P)|, |By(P)|, detected by the magnetic field detection device at a point in space. |Bz(P)| controlled, in particular regulated, of each magnetic field B1, B2 and B3. In this way, situational detection of the magnetic field strength can be used to adapt the transmission power of the magnetic fields B1, B2, B3. For this purpose, the first object can comprise, for example, a communication device for realizing a, in particular wireless, communication connection with a communication device of the reference object, the control being made possible via the communication connection. Furthermore, a rough distance measurement can already take place by evaluating a reception level of the communication link. Furthermore, the transmission power can also be adjusted on the basis of information that is situationally detected by means of additional sensors. For example, information about an environment, in particular about a distance, of the first object and the reference object can be detected using a radar and/or using camera-based sensors, on the basis of which the transmission power is adapted depending on the situation. In this way it is possible, for example, to operate a transmission level as low as possible, for example only 10 dB above the noise of the magnetic field detection device, and in this way to minimize energy and the potential for interference.

The magnetic field generating device is set up to generate the magnetic fields B1, B2, B3 with distinguishable modulation frequencies f1, f2, f3, in particular to emit them by means of the emitter coils Tx1, Tx2, Tx3. The modulation frequencies refer to frequencies of, in particular, low-frequency signals that are modulated onto the magnetic fields B1, B2, B3. In particular, the modulation causes the intensity (magnetic field strength) of a respective magnetic field to vary, in particular to vary between “on” and “off”. The modulation frequencies f1, f2, f3 differ in each case. If the magnetic field B1 is emitted over a period of one second, for example, then this magnetic field can be the carrier of a modulation signal f1, which is emitted during the emission of the magnetic field B1 with its emission. Sufficient differentiation of the modulation frequencies f1, f2, f3 is determined by the resolution of a receiver, here the magnetic field detection device. In an exemplary embodiment of the method, the modulation frequency f1, f2, f3 of the magnetic fields is greater than 30 kHz and/or less than 150 kHz. In particular, modulation frequencies restricted in this way allow influences from the earth's magnetic field and/or interference signals, for example from the radio spectrum, to be avoided.

The magnetic field generating device is assigned to the reference object, i.e. it has a fixed spatial relationship to it. In this way it can be realized that a relative position P, which is determined with respect to the magnetic field generating device, can at least be converted into a relative position with respect to the reference object. In one embodiment, the magnetic field generating device is designed as a component part of the reference object and is thus stationarily connected to it. In particular, the reference object can also be realized by the magnetic field generating device.

The magnetic fields B1, B2, B3 acting at a point in space are detected by the magnetic field detection device. The magnetic field detection device is assigned to the first object, in particular integrated into it or represents this first object The detection device is used to detect the at least three directional magnetic fields B1, B2, B3 at the location of the magnetic field detection device. The magnetic field detection device is set up to detect the effective magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| - or the effective magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| and associated magnetic field directions (for example by means of a vector magnetometer) - and to detect the modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3. Using the detected modulation frequency f1, f2 or f3, a detected magnetic field strength can be unambiguously assigned to a magnetic field B1, B2 or B3 emitted by the magnetic field generating device. In this way, the magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| of each magnetic field B1, B2 and B3 are differentiated from one another and evaluated separately in this way (also denoted as |B1 ^x,y,z |, |B2 ^x,y,z |, |B3 ^x,y,z |). The relative position P in the emitted magnetic field B1, B2, B3—ie relative to the magnetic field generating device and thus relative to the reference object—can be determined (via an overdetermined system of equations) on the basis of the nine measured values that can be recorded in this way. For the precise derivation of the position from the detected magnetic field strengths, reference is made to the prior art cited at the outset.

The magnetic field detection device includes all of the signals for detecting the effective magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| and modulation frequencies f1, f2, f3 required components, for example a control device, an electrical receiving circuit, a power supply, etc. In one embodiment of the method for determining a relative position, the magnetic field detection device comprises at least one magnetic field sensor, in particular three magnetic field sensors, from a list of magnetic field sensors, where the list includes at least quantum sensors, TMR sensors, GMR sensors, receiving coils (e.g. pickup coils), fluxgate sensors and Hall sensors. Such a magnetic field sensor is suitable for detecting effective magnetic field strengths—possibly also effective magnetic field strengths and associated magnetic field directions—as well as modulation frequencies of magnetic fields. The detection of a magnetic field strength conceptually also includes the detection of a magnetic flux density, i.e. the signal amplitude of a magnetic field sensor.

In one embodiment of the method for determining a relative position, the magnetic field detection device comprises at least one magnetic field sensor, which is implemented as a color center-based magnetic field sensor, in particular as a quantum sensor based on color centers (nitrogen vacancies) in diamond. In particular, color center-based magnetic field sensors, as are known in principle from the prior art (e.g. from DE 102014219550 A1 ), enable a three-dimensional, direction-dependent measurement of the magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| with only one magnetic field sensor. The sensitivity of such sensors can be significantly higher than conventional magnetic field sensors such as Hall sensors, TMR sensors, fluxgate sensors, pickup coils or the like (e.g. with a resolution of less than 1 pT/√(Hz) over a large measuring range of more than 1 Tesla), so that in principle a larger working range or functional range of the method for determining a relative position can be implemented. Furthermore, requirements for a required installation space for accommodating the magnetic field sensor can advantageously be reduced (with up to a few cubic centimeters of installation space; for example in comparison to receiver coils, which can easily have a diameter of around ten centimeters). In addition, a color center-based magnetic field sensor is in principle also suitable for vector magnetometry, ie a simultaneous determination of the direction of the detected magnetic fields. In one exemplary embodiment, the method is operated with modulation frequencies in the range between 10 Hz and 50 Hz in order to advantageously utilize a high sensor sensitivity of the color center-based magnetic field sensor. The modulation frequencies f1, f2, f3 can each differ by 3 Hz, for example.

In one embodiment of the method, the magnetic field detection device has three magnetic field sensors of the type described, which alternately have a defined, in particular orthogonal, arrangement and consequently an alternately defined, in particular orthogonally aligned, sensitivity to one another. A respective magnetic field sensor detects the effective magnetic field strengths |Bx(P)| or |By(P)| or |Bz(P)| and the modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3.

In one embodiment of the method for determining a relative position, the magnetic field detection device comprises at least one magnetic field sensor, which is implemented as a receiver coil, in particular an RF coil. The method can be implemented in a particularly simple manner using a magnetic field detection device that includes at least three receiver coils, in particular RF coils. The three receiver coils alternately have a defined arrangement relative to one another, in particular an alternately orthogonal arrangement relative to one another. Each of the three receiver coils - labeled Rx, Ry, Rz - detects the effective magnetic field strengths of the magnetic fields B1, B2, B3 and their modulation frequencies f1, f2, f3.

In one embodiment of the method, in particular for use in domestic interiors, at least one coil of an induction hob and/or at least one coil of an inductive charging station is used as at least one emitter coil Tx1, Tx2, Tx3 of the magnetic field generating device. In this case, a coil—located below the cooking surface of the induction hob in the first case—is operated in such a way that a corresponding magnetic field is generated and emitted. In particular, it is conceivable that switching on and/or switching off and/or configuring an operation (for example with regard to magnetic field strength or modulation frequency) of the coil takes place using a control device that operates the coil. In particular, it is conceivable that for this purpose the control device, in particular of the cooker or the inductive charging station, communicates with the reference object via a communication interface. In particular, this embodiment is suitable for robots used indoors at home, for example robot vacuum cleaners or the like. In this way, already existing components can be used, so that the method can be operated with fewer separately required emitter coils.

In one embodiment of the method for determining a relative position, an energy store of the first object is inductively charged, at least temporarily, by means of at least one emitter coil Tx1, Tx2, Tx3 of the magnetic field generating device. In this way, a further functionality based on at least one emitter coil of the system can be provided. In one embodiment, the reference object can be implemented as a kind of docking station for the first object, with the first object being inductively charged by an emitter coil of the reference object as soon as it is in the docking station.

The relative position P of the first object with respect to the at least one reference object is determined using an evaluation device from the detected magnetic field strengths |Bx(P)|, |By( P)|, |Bz(P)|, determined. The evaluation device is specially set up to carry out the corresponding method steps for determining the relative position. Corresponding method steps can be implemented, at least in part, in the form of software, in particular in the form of a computer-implemented method, or in a mixture of software and hardware. For example, the evaluation device can be implemented in the form of an electrical circuit and, in particular, can include a bandpass filter and/or an amplifier. In particular, the evaluation device includes a processor device for carrying out corresponding method steps. It is conceivable for the evaluation device to be assigned to the first object, to the reference object or also to be implemented separately from these, for example in a cloud, on a separate computer or the like. In this case, the evaluation device can have control electronics, which in particular also includes means for communication with other components, for example the magnetic field detection device, the magnetic field generating device, etc. Furthermore, the processor device can access at least one memory device in which algorithms are stored, at least in part, as a machine-readable computer program. The computer program contains instructions which, when executed by the processor device of the evaluation device, cause the processor device to determine the relative position P of the first object with respect to the at least one reference object from the detected magnetic field strengths |Bx(P)|, |By(P)|, |Bz( P)| to determine.

In one embodiment of the method for determining a relative position, the modulation frequencies f1, f2, f3 are transmitted from the magnetic field generating device to the magnetic field detection device and/or to the evaluation device in a further method step, with the transmitted modulation frequencies f1, f2, f3 being used to improve a signal-to-noise Ratio when determining the relative position P are used. For example, the transmitted modulation frequencies can be used for more precise detection of the modulation frequencies, in particular for determining the modulation frequencies from a time profile of the detected magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)|. In particular, knowledge of the phase relationship between the magnetic field generation device (ie the emitter coils Tx1, Tx2, Tx3) and the magnetic field detection device can be used to improve accuracy when carrying out the method, in particular when determining the relative position. In one embodiment of the method for determining a relative position, the modulation frequencies f1, f2, f3 are transmitted using a radio link. For example, a LoRa, a WLAN, a Bluetooth radio connection or the like are suitable for the radio connection. In one embodiment, the modulation frequencies can be in the range of 30 kHz, while the modulation frequencies f1, f2, f3, in particular synchronization with the modulation frequencies f1, f2, f3, are transmitted by a radio link - in particular as a carrier signal - that has a 30 MHz signal. Alternatively or additionally, via the radio link Synchronization pulse and / or a multiple of the frequencies f1, f2, f3 are transmitted.

In one embodiment of the method for determining a relative position, the transmitted modulation frequencies are used as a reference signal of a lock-in amplifier of the magnetic field detection device and/or the evaluation device. In this way, even with large distances between the magnetic field generation device and the magnetic field detection device, which cause a poor signal-to-noise ratio, a respective detected magnetic field B1, B2, B3 can be identified or assigned via its modulation frequency in a particularly simple manner by specifying the frequencies in that the recorded magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| the corresponding modulation frequencies can be filtered out and thus detected via the synchronized lock-in amplifier.

In one embodiment of the method for determining a relative position, the relative position P of the first object is determined, in particular optionally, with respect to a plurality of reference objects, each reference object comprising an associated magnetic field generating device. In this way it is possible in particular to switch between directional magnetic fields B1, B2, B3, which are generated by different magnetic field generating devices with different frequencies. A determination of a relative position is possible with regard to different reference objects. All statements made with regard to the magnetic field generating device of the at least one reference object apply to the magnetic field generating devices of the reference objects. In particular, it is conceivable to determine relative positions P in parallel or successively or also as an average with respect to a number of references. It is conceivable to determine the relative position with respect to two, three or more reference objects. For example, in the case of a drone that is intended to deliver packages, it can be provided, in particular optionally, to determine a relative position with respect to the ground (e.g. with regard to a landing position) and with respect to the package, in particular a top side of the package.

In particular, the mutual relative positions of the plurality of reference objects can also be determined from the determined relative positions of the first object with respect to the plurality of reference objects (determination P1 between reference object 1 and first object, determination P2 between reference object 2 and first object, from this P3 (= P1 + P2) between reference object 1 and reference object 2 can be determined).

In an alternative, in particular analogous, embodiment of the method for determining a relative position, the relative position P of a reference object is determined, in particular selectively, with respect to a plurality of first objects, each reference object comprising an associated magnetic field generating device and each first object comprising an associated magnetic field detection device. In this embodiment, the relative position P of a plurality of first objects is determined, in particular optionally, in relation to at least one reference object. Since the magnetic field generation device and the magnetic field detection device are simply exchanged, this embodiment is considered to be analogous.

In one embodiment of the method for determining a relative position, each modulation frequency f1, f2, f3 of the magnetic fields B1, B2, B3 encodes system information and/or all modulation frequencies f1, f2, f3 jointly encode system information. In particular, it is conceivable to provide the first object and/or the evaluation device with further information about the reference object and/or about other properties relating to the system (e.g. location, identification number or the like) via the modulation frequencies. In this way, in addition to the relative position, at least one piece of additional information can be transmitted to the first object and/or the evaluation device and made available in this way. For example, an assignment or distinguishability of relative positions that are determined for different reference objects can be achieved via the coding (coding, for example, via an ID assigned to each reference object).

In one embodiment of the method for determining a relative position, an influence of an interference field is detected and a detected magnetic field strength |Bx(P)|, |By(P)|, |Bz(P)| corrected by the evaluation device for the influence of the interference field and/or the influence of the interference field by controlling and/or regulating an electromagnetic superposition field emitted by means of at least one compensation coil when detecting the magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| compensated. In this way it is possible to determine a relative position more precisely. Alternatively or additionally, a requirement for the sensitivity of the magnetic field detection device can advantageously be reduced. In particular, magnetic interference fields located at the location of the first object can be advantageously compensated for in this way. In particular, such interference with an electrical Capture and compensate compensation circuit. In this case, the compensation circuit can also include receiving coils, amplifiers, etc. in addition to at least one compensation coil. The receiving coil(s) and/or compensation coil(s) is/are located as close as possible to the magnetic field detection device. It is also conceivable to minimize, in particular to prevent and/or compensate and/or measure an influence acting at least during a period in which the magnetic fields B1, B2, B3 are detected and to compensate later in an evaluation. A control device and/or evaluation device that carries out the method can be set up to compensate for an influence. The method can be implemented, at least in part, in the form of software or in a mixture of software and hardware. In particular, it is conceivable that the influence can be measured using an essentially temporally parallel detection of the magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| carried out reference measurement is determined. In particular, it is conceivable that the influence during the detection of the magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| is actively compensated as a function of the determined influence, for example by controlling and/or regulating and/or adjusting an electromagnetic superposition field that is generated using the at least one compensation coil. Alternatively or additionally, it is conceivable that the influence is avoided and/or compensated by using the data recorded on the influence of an interference field to determine a point in time at which the influence is relatively small, in particular negligible, with the Detection of the magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| carried out at this time.

In one embodiment of the method for determining a relative position, when determining the relative position P, further position data, in particular further position data from a further internal and/or external sensor device, are included to increase the precision and/or to determine an absolute position. In this context, “include” is also to be understood in particular as merging or correlating. The additional position data can represent relative or absolute position data, for example. Relative position data can be, for example, position data from acceleration sensors, yaw rate sensors, odometry data or the like. Absolute position data can be GPS or GNSS data, for example. Radar, lidar or video sensors can also be used to determine a position. In one embodiment of the method, the additional position data is recorded as absolute position data, with the relative position P being determined relative to this absolute position data. Using absolute position data, an absolute position can thus be determined from the determined relative position. Furthermore, by means of such a sensor fusion, a plausibility check and/or correction of the relative position can be carried out and the relative positions obtained can be made more robust in this way. Furthermore, it is conceivable to dynamically detect distortions in the detected magnetic fields, which affect errors in the determined relative position, via a sensor fusion with other sensor data. In particular, such a fusion of position data can be used to detect magnetic field distortions (e.g. induced by interference fields) in the magnetic fields B1, B2, B3 and, with this knowledge, position-dependent correction data can be derived and, for example, stored in a magnetic field map, which can then be used when the relative position is determined again or further are taken into account. Furthermore, such errors can be used, for example, via a machine learning algorithm to improve the positioning accuracy. As a result, the occurrence of magnetic objects and associated interference fields (magnetic field distortions) can be detected during operation of the method and the method for determining a relative position can be corrected dynamically. In particular, correction data can be continuously updated, so that temporary magnetic field distortions can also be recognized quickly and corresponding correction data can be determined, which are available for subsequent determinations of a relative position.

• - Erzeugen zumindest dreier gerichteter Magnetfelder B1', B2', B3' unterscheidbarer Modulationsfrequenzen f1', f2', f3' mittels einer dem weiteren Referenzgegenstand zugeordneten weiteren Magnetfelderzeugungsvorrichtung, wobei die weitere Magnetfelderzeugungsvorrichtung zumindest drei Emitterspulen Tx1', Tx2', Tx3' umfasst, die wechselweise eine definierte Anordnung zueinander aufweisen,
• - Erfassen von Magnetfeldstärken |Bx'(P')|. |By'(P')|, |Bz'(P')| und Modulationsfrequenzen f1', f2', f3' der Magnetfelder B1', B2', B3' mittels einer Magnetfelderfassungsvorrichtung des Referenzgegenstands,
• - Ermitteln der relativen Position P' des Referenzgegenstands bezüglich des zumindest einen weiteren Referenzgegenstands mittels einer Auswertevorrichtung aus den erfassten, über die erfassten Modulationsfrequenzen f1', f2', f3' den gerichteten Magnetfeldern B1', B2', B3' zuordenbaren Magnetfeldstärken |Bx'(P')|, |By'(P')|, |Bz'(P')|.

In one embodiment of the method for determining a relative position, a relative position P' of the at least one reference object with respect to at least one further reference object is determined, comprising:

• - generating at least three directed magnetic fields B1', B2', B3' of distinguishable modulation frequencies f1', f2', f3' by means of a further magnetic field generating device assigned to the further reference object, wherein the further magnetic field generating device comprises at least three emitter coils Tx1', Tx2', Tx3', which alternately have a defined arrangement to one another,
• - Detection of magnetic field strengths |Bx'(P')|. |By'(P')|, |Bz'(P')| and modulation frequencies f1', f2', f3' of the magnetic fields B1', B2', B3' by means of a magnetic field detection device of the reference object,
• - Determination of the relative position P' of the reference object with respect to the at least one further reference object by means of an evaluation device from the detected, via the detected modulation frequencies f1', f2', f3' the directed magnetic fields B1', B2', B3' assignable magnetic field strengths |Bx'(P')|, |By'(P')|, |Bz'(P')|.

In particular, it is also conceivable to operate several reference objects in a staggered manner, with each "intermediate" reference object having at least one magnetic field generating device and a magnetic field detection device, so that this reference object can detect both magnetic fields to determine its own relative position and magnetic fields to determine the relative position of a subsequent first one Object and / or reference object can generate. In particular, entire chains of staggered reference objects are conceivable (reference object 1-reference object 2-reference object 3-first object). In particular, in this way each "intermediate" reference object serves as a first object whose relative position P with respect to the preceding reference object is determined. It should be noted that the magnetic field detection device and the magnetic field generating device can also be implemented as a single component that is used both as a magnetic field detection device and as a magnetic field generating device (for example as a coil system that is operated in a receiving mode and in a transmitting mode).

Advantageously staggered relative positions can be determined in this way. Application examples for this can be, for example, robots navigating in a robot swarm, with the position of each robot being determined relative to the other robots, i.e. the robots are localized among themselves. If the relative positions of the robots are also exchanged, joint path planning (swarm intelligence) is possible. This could, for example, be used specifically to extend a range or the like. In addition, the method can also be transferred to the control of robot arms, etc., in which case, for example, a relative position of each individually movable part of the robot arm can be determined relative to each other movable part of the robot arm. All the features listed in this document also apply to the at least one further reference object, for example that in a further method step the modulation frequencies f1', f2', f3' are transmitted from the further magnetic field generating device assigned to the further reference object to the magnetic field detection device of the reference object and/or to the evaluation device , wherein the transmitted modulation frequencies f1', f2', f3' are also used to improve a signal-to-noise ratio when determining the relative position P'.

In one embodiment of the method for determining a relative position P, magnetic field strengths |Bx _i (P)|, |By _i (P)|, |Bz _i (P)| and modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3 are detected, with a relation of the magnetic field strengths |Bx _i (P)| and |Bx(P)| to each other and/or |By _i (P)| and |By(P)| to each other and/or |Bz _i (P)| and |Bz(P)| to each other is determined. A defined arrangement means, in particular, a defined distance and a defined alignment of the magnetic field detection devices i to one another. in particular, the relation is expressed as a component-wise relation of the magnetic field strengths |Bx _i (P)| and |Bx(P)| to each other and/or |By _i (P)| and |By(P)| to each other and/or |Bz _i (P)| and |Bz(P)| identified to each other. A relation is to be understood as meaning any mathematical relationship in which the magnetic field strengths can be compared, in particular component-by-component, or can be related to one another. In particular, a difference, a quotient, a larger/smaller ratio or the like is conceivable. In one embodiment of the method for determining a relative position P, the relation, in particular in the form of a magnetic field gradient, is determined as a difference |Bx _i (P)| - |Bx(P)|, |By _i (P)| - |By(P)| or |Bz _i (P)| - |Bz(P)| determined. In this way, a particularly simple relation can be specified, with the magnetic field gradient being determined as a difference formed in pairs. Alternatively or additionally, a relative position P could also be used as a quotient |Bx _i (P)| / |Bx(P)|, |By _i (P)| / |By(P)| or |Bz _i (P)| / |Bz(P)| be determined. Furthermore, an accuracy in the determination of the relative position P can also be increased by using the relation.

In one embodiment of the method for determining a relative position P, in which the relation is determined as a difference, the relative position P, which in particular is otherwise possibly ambiguous (particularly ambiguous), is uniquely identified using a sign of the relation. In an alternative embodiment of the method, in which the relation is determined as a quotient, a comparison of the relation with the value 1 is used to carry out a clear identification of the relative position P, which in particular may otherwise be ambiguous (particularly ambiguous). In this case, a relative position can initially have an ambiguity, in particular due to a symmetrical course of the magnetic fields B1, B2, B3 generated by the magnetic field generating device. A magnetic field generated by an emitter coil has regions of the magnet in the direction perpendicular to the winding plane field where the magnetic field strength is minimal (possibly 0 T). On both sides of this axis of mirror symmetry (corresponding to the normal to the winding plane of the emitter coil) and mirror-symmetrical to the winding plane of the emitter coil are regions of identical magnetic field strength, so that an (ideal, undisturbed) magnetic field basically comprises four areas of equal magnetic field strength (located in four quadrants with which emitter coil in the center). According to the invention, a suitable measure can be specified using the relation in order to assign the relative position to a quadrant despite these ambiguities. In particular, a transition between each two adjacent quadrants can be detected using the method according to the invention. For this purpose, the relationships of the detected magnetic field strengths are continuously evaluated and in this way continuously determined magnetic field gradients. In a method implementation in which the relation is determined as a difference, the sign of the relation (the difference) reverses as soon as a transition between two quadrants has taken place. In a method implementation in which the relation is determined as a quotient, the quotient changes from a value greater than one to a value less than one as soon as a transition between two quadrants has taken place. Thus, transitions of the first object between different quadrants can be determined. Consequently, the relative position P of the first object, which is otherwise possibly ambiguous (particularly ambiguous), can also be clearly assigned to one of the four quadrants, in particular assuming that at the beginning of a movement of the first object the starting position is one of the Can be assigned to a quadrant (e.g. because the base station is located there). For example, if a first object, which is conceivable as a robot, moves, then relations can be determined continuously. If this relation then changes the sign (or from a value greater than one to a value less than one (or vice versa)), a transition between two adjacent quadrants can be derived.

• - magnetfeldsensitive Sensoren wie beispielsweise Kompass, Magnetfeldsensor, Fluxgate-Magnetometer und Hall-Sensor;
• - kapazitive Sensoren;
• - positionssensitive und/oder lagesensitive Sensoren wie beispielsweise GPS, Positionssensor, Odometriesensor und Einschlagwinkelsensor für ein Lenkrad oder Steuerrad;
• - geschwindigkeitssensitive und/oder beschleunigungssensitive Sensoren wie beispielsweise Gyroskop, Inertialsensorik und Beschleunigungssensoren;
• - abstandssensitive Sensoren wie beispielsweise Laserentfernungsmesser, Ultraschallsensoren und Radar, ...
• - drucksensitive Sensoren,
• - optische Sensoren,
• - spannungssensitive und/oder stromsensitive Sensoren

oder eine Kombination derer.In one embodiment of the method for determining a relative position P, a change in direction of movement, in particular a reversal of direction of movement by 180°, of the first object is detected by means of a rotation-sensitive sensor device, with a change in direction of movement of the first object, in particular by more than 90°, a sign reversal the relation or an inversion of the relation (change in value from less than one to greater than one (or vice versa) by forming the reciprocal value) is taken into account, in particular carried out. In this way, it can also be ruled out that a change in the direction of movement, in particular a change in direction of movement by 180°, leads to an (unnoticed or unexpected) change in the relation, which is otherwise generated by a quadrant transition. “Take into account” means in particular that such a change in value is corrected or compensated for mathematically in an evaluation. A rotation-sensitive sensor device is to be understood in particular as a sensor device that is sensitive to a spatial rotation and/or change in direction of the first object (for example implemented by acceleration sensors, cameras or the like). In principle, all sensors are suitable for this, by means of which information about a direction of movement of the first object can be derived. For example

• - Sensors sensitive to magnetic fields such as compasses, magnetic field sensors, fluxgate magnetometers and Hall sensors;
• - capacitive sensors;
• - Position-sensitive and / or situation-sensitive sensors such as GPS, position sensor, odometry sensor and steering angle sensor for a steering wheel or steering wheel;
• - speed-sensitive and/or acceleration-sensitive sensors such as gyroscopes, inertial sensors and acceleration sensors;
• - Distance-sensitive sensors such as laser range finders, ultrasonic sensors and radar, ...
• - pressure-sensitive sensors,
• - optical sensors,
• - voltage-sensitive and/or current-sensitive sensors

or a combination of those.

It should be noted that an orientation (and thus the direction of movement of the first object) can in principle also be determined via the existing magnetic field detection device by evaluating a DC component in the measurement signals of the detected magnetic field. This has the advantage that no additional angular rate sensor or compass has to be provided.

Alternatively or additionally, it is conceivable to measure a phase position of the magnetic fields B1, B2, B3 by means of a sensor in order to determine a clear identification of the relative position P of the first object with respect to the reference object, which in particular may otherwise be ambiguous.

Furthermore, interference fields, such as those generated by metal objects such as vehicles or buried objects, can be detected particularly efficiently in this way. In one embodiment of the method for determining a relative position P, deviations in the relation from expected desired relations according to the defined arrangement of the magnetic field detection device and the at least one further magnetic field detection device i are evaluated, in particular identified, to detect magnetic field distortions. In other words—since the distance and angle of the magnetic field sensors to one another are known—the values of the detected magnetic fields of the individual magnetic field detection devices can be used for a comparison with values expected on the basis of the arrangement. This can be evaluated in particular during a movement of the first object and such unexpected interference fields, ie magnetic field distortion, can be detected and recorded. In particular, such deviations can be detected in a particularly simple manner and interference fields can be inferred therefrom.

In one embodiment of the method for determining a relative position P, detected magnetic field distortions or interference fields are stored, in particular updated and/or merged, in a magnetic field map, in particular a two-dimensional or three-dimensional magnetic field map. “Fuse” is to be understood in particular as “overwriting”, “averaging”, “interpolating”, “extrapolating”, “correlating” or the like with other sensor data. In this way, detected magnetic field inhomogeneities and/or interference fields can be taken into account when carrying out the method for determining a relative position.

In one embodiment of the method for determining a relative position P, two further magnetic field detection devices i are used. In particular, the three magnetic field detection devices i have an arrangement relative to one another that forms a triangle. In this way, the relationships, in particular magnetic field gradients, can be determined in a simple manner in 2 independent directions, in particular two orthogonal directions.

In one embodiment of the method for determining a relative position P, the presence of at least one magnetic field BSQ of an external radiation source, in particular a magnetic field generating device not assigned to the reference object, is detected in a further method step. In this way it can be detected whether other magnetic fields, for example interference fields from other magnetic field sources or magnetic fields from other reference objects, are present in addition to the magnetic fields B1, B2, B3 generated to carry out the method for determining a relative position. In particular, this detection can be carried out repeatedly, in particular regularly repeated, for example quasi-continuously or continuously. According to the invention, this information can be used to adapt or improve the method for determining a relative position P.

In one embodiment of the method for determining a relative position P, the presence of the at least one magnetic field BSQ is detected using the magnetic field detection device of the first object and/or using the magnetic field generating device assigned to the reference object and/or using at least one additional receiver. In particular, it is conceivable that the magnetic field detection device is used to detect the presence of the at least one magnetic field BSQ by means of a "reception spectrum" that has changed due to the magnetic field BSQ in terms of the expected magnetic fields B1, B2, B3 and their associated modulation frequencies f1, f2, f3. It is also conceivable that the presence of the at least one magnetic field BSQ is detected by the magnetic field generating device by operating it in a receive mode. This receiving mode can be implemented, for example, by briefly connecting an emitter coil or several emitter coils to receiving electronics during a pause in transmission of the magnetic field generating device. An additional receiver can be implemented as a magnetic field sensor of basically any configuration, for example as a Hall sensor or the like.

In one embodiment of the method for determining a relative position P, the modulation frequencies f1, f2, f3 are selected, in particular modified, depending on the presence of the at least one magnetic field BSQ. In an alternative or additional embodiment of the method for determining a relative position P, pause times in the modulation t1, t2, t3 of the magnetic fields B1, B2, B3 are selected, in particular modified, depending on the presence of the at least one magnetic field BSQ. In another alternative or additional embodiment of the method for determining a relative position P, pause times in the generation T1, T2, T3 of the magnetic fields B1, B2, B3 are selected, in particular modified, depending on the presence of the at least one magnetic field BSQ. In particular, the modulation frequencies f1, f2, f3 and/or pause times in the modulation t1, t2, t3 and/or pause times in the generation T1, T2, T3 can be modified or selected in such a way that one on the External radiation source adapted generation of the same takes place. Alternatively or additionally, the presence of the at least one magnetic field BSQ can also be output to a user of the method for determining a relative position P.

In one embodiment of the method for determining a relative position P, the detection of the presence of at least one magnetic field BSQ of an external radiation source includes at least one determination of a modulation frequency fSQ of the at least one magnetic field BSQ. The modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3 can advantageously be chosen to be different from the modulation frequency fSQ. In this way, the frequency range of the magnetic field BSQ can be explicitly excluded, so that the modulation frequencies f1, f2, f3 used can be distinguished, i.e. in particular far enough away from fSQ in the frequency band. In this case, the distances in the frequency band can be selected depending on a quality in the detection of the magnetic fields B1, B2, B3, so that these distances can turn out to be smaller with high quality (and consequently already quite precise determination of the relative position P).

In one embodiment of the method for determining a relative position P, the detection includes determining pause times in the modulation tSQ and/or pause times in the generation TSQ of the at least one magnetic field BSQ. The pause times in the modulation t1, t2, t3 or the pause times in the generation T1, T2, T3 of the magnetic fields B1, B2, B3 can advantageously be selected in such a way that the modulation of the magnetic fields B1, B2, B3 in the pause times in the modulation tSQ or the generation of the magnetic fields B1, B2, B3 takes place in the pause times in the generation TSQ of the at least one magnetic field BSQ. In this way, specific pause times in the external magnetic field BSQ - in its modulation and/or in its generation, ie emission - can be used explicitly when generating the magnetic fields B1, B2, B3 by generating the modulation with the modulation frequency f1 in these pause times , f2, f3 takes place or the generation of the magnetic fields B1, B2, B3 per se takes place in these pause times. Furthermore, time intervals--between the generation of the magnetic fields or between the modulations of the magnetic fields--can be chosen in such a way that detection of the magnetic fields B1, B2, B3 that is as free of interference and free of overlap as possible is ensured.

In one embodiment of the method for determining a relative position P, the magnetic field BSQ of the external radiation source, in particular the magnetic field generating device not assigned to the reference object, is used to increase the range of the method for determining the relative position P of the first object. It is conceivable that at the maximum range distance of the first reference object (i.e. at a distance in which a magnetic field B1, B2, B3 can still be detected) further "satellite reference objects" are installed, which, for example, transmit on other frequencies during the transmission breaks. In principle, however, the "satellite reference objects" can also transmit on the same frequencies f1, f2, f3 if a different frequency sequence - for example f2, f1, f3 - is used and monitored.

In one embodiment of the method for determining a relative position P, the magnetic field BSQ of the external radiation source, in particular the magnetic field generating device not assigned to the reference object, originates from a method according to one of the preceding claims operated in parallel. This makes it possible to operate a number of methods for determining a relative position P—equivalent to a number of systems that implement the method—in parallel with one another. For example, several autonomous lawn mowers can be operated in parallel using the method according to the invention, as can be the case in a neighborhood. In this case, pause times of a robot system (comprising a reference object and a first object integrated in the robot) are determined, with the further robot system then placing its own transmission activities in previously determined pause times. In particular, the other robot systems then transmit on other frequencies and/or during the pause times of the other robot systems. Furthermore, the above-mentioned swarm of robots can also be implemented using this embodiment of the method.

In one embodiment of the method for determining a relative position P, the first object is implemented as a hand-held electrical device, in particular a laser range finder, a hand-held power tool, a gaming controller or the like, and a function, in particular the hand-held one, is implemented depending on the relative position P electrical device controlled. The reference object can be positioned stationary in space. The implementation of the method serves to determine the position, in particular three-dimensionally, of the electrical device in space. The electrical device can be realized, for example, as a laser range finder, a further measurement functionality, in particular a measurement of indirect distances, being made possible as a function of a relative position of the laser range finder, as is the case for example point in DE 102016211742.4 A1 or in DE 102018201692.5 A1 is revealed. An implementation of the method for spatial tracking of the relative position (here relative position and orientation) of a locating device can also be used, so that a spatial progression of locating objects, which are hidden in a wall, for example, can be detected in three dimensions and depending on the position. The data, including location information and relative position, can then be used for documentation and further planning in digital models (cf. "Building Information Modeling").

In contrast to inertial sensors, as is often used in the prior art, the method according to the invention can also advantageously be used to determine a relative position of a vibrating machine, for example a percussion drill. In the case of a drilling machine, for example, depending on a user specification, for example "execution of a horizontal hole", based on the determined relative position of the drilling machine, the user can be informed of how the target alignment is achieved and when the target alignment is achieved. Furthermore, in particular the accuracy in determining the position can be significantly increased compared to inertial sensors. Electrical entertainment electronics devices such as AR glasses, game controllers or the like are also conceivable, the relative position of which is determined using the method according to the invention.

In one embodiment of the method for determining a relative position P, the first object is implemented as a robot, in particular an autonomous robot, in particular a robotic vehicle such as a logistics robot, a vacuum cleaner or lawnmower or the like, and depending on the relative position P, a function, in particular the Robotic vehicle controlled. A robot, in particular an autonomous robot, is to be understood to mean, in particular, an at least partially automatic mobile device which performs work, for example processing a surface, at least partially automatically. In addition, a device is to be understood in particular that moves at least automatically and/or moves autonomously in a predetermined area, in particular in a work area or in a processing area. Typical areas of application of such robotic vehicles include a wide range of activities such as sweeping, vacuuming, cleaning, mowing the lawn, collecting (collecting), sorting, watering, fertilizing, mapping or the like. The reference object can, for example, be stationarily positioned as a docking station (base station) of the robot, for example as a docking station for an autonomous lawnmower in the garden. Docking maneuvers (for example to the docking station) can be carried out particularly precisely when this method is implemented. Furthermore, the relative position can be determined in a large area—advantageously without a boundary wire, as is used in the prior art, cf. DE 102014226077.9 A1 - Take place with high precision, in particular by being able to dispense with complex and inaccurate sensors such as odometry sensors (which is susceptible to slippage of the drive means). For robots working indoors, it is conceivable to use a coil of an induction hob and/or a coil of an inductive charging station (e.g. the docking station) as at least one emitter coil Tx1, Tx2, Tx3 of the magnetic field generating device.

In one embodiment of the method for determining a relative position P, the first object is implemented as a flying object, in particular as a drone, and depending on the relative position P, a function, in particular of the flying object, particularly the drone, is controlled.

In one embodiment of the method for determining a relative position P, a boundary of a work area, in particular a work area of a robot, is determined using the first object by guiding the first object along at least one boundary of the work area and successively determined relative positions P are recorded and /or be evaluated. In particular, the reference object can already be placed at a place of use, the work area then being localized with the first object—which is designed, for example, as a hand-held rod—by guiding the rod along the boundary of the work area. The trajectory recorded in this way can be digitized and then used to carry out further processes, for example navigation processes of the robot. In this way, the method according to the invention can be used for teaching (teach-in) a robot with regard to an activity area—for example an autonomous lawnmower with regard to an area to be mowed in the garden. Due to the high precision in determining the relative position, the method allows a particularly fine resolution of the boundaries of the working area, which, for example, cannot be achieved with a boundary wire (see prior art above) or can only be achieved with great effort.

In one embodiment of the method for determining a relative position P, a distance, ins in particular a distance or length of a path between a first point and a second point is determined by guiding the first object, in particular along the path, from the first point to the second point and successively determining relative positions P are recorded and/or evaluated will. Furthermore, the evaluation of a trajectory covered by the first object—for example between two points—allows a distance between these points along the trajectory to be determined. The first object can also be implemented in the form of a hand-held stick.

In one embodiment of the method for determining a relative position P, at least the first object is assigned to a robot arm, in particular the reference object is also assigned to the robot arm, and using successively determined relative positions P, a movement and/or a function, in particular of the robot arm, is controlled . For example, a fully integrated robot arm can be realized in this way, which can evaluate and consequently control an exact position of each movable part of the robot arm at any time without additional complex sensors (such as inertial sensors, protractors, distance meters or the like). For example, the reference object can be assigned to a fuel filler neck of a vehicle, so that an autonomously acting refueling robot can automatically align its filling pistol, which is equipped with the first object, and consequently can refuel the vehicle automatically.

In one embodiment of the method for determining a relative position P, the reference object is assigned to a surveillance system, in particular a smoke detector or fire detector, and a relative position P of a person equipped with the first object is detected. For example, the reference object can be integrated into the smoke detector. In this way, movement profiles of people relative to the smoke detector can be advantageously detected, which can be used, for example, in the context of fire brigade operations to coordinate and protect the firefighters deployed. It is conceivable that each person carries a first object assigned to the body, the relative position of which is determined. It is also conceivable that the frequencies f1, f2, f3 are used to encode further information - for example with regard to a room size, a position of the smoke detector in the room, dangerous goods in the room, a room name or the like - and transmitted to the first object in such a way that a further processing or output of the information can take place.

Furthermore, a system is proposed, comprising a first object, at least one reference object and an evaluation device, wherein the system, in particular the evaluation device, is set up to carry out the method according to the invention. All of the above statements regarding the method and the components used in the method, in particular the magnetic field detection device, the magnetic field generating device, the evaluation device, etc., also apply as disclosed for the system.

A first object and/or a reference object is also proposed for use in a system according to the invention or for use in a method according to the invention. In particular, a first object is proposed which is implemented as a hand-held electrical device, in particular a laser range finder, a hand-held power tool, a gaming controller or the like, as a robot, in particular an autonomous robot, in particular a robotic vehicle such as a vacuum cleaner or lawn mower or the like, as a a flying object, in particular as a drone, as a hand-held stick and/or as part of a robot arm. In particular, a reference object realized as a docking station or as a smoke detector is proposed.

character list

The invention is explained in more detail in the following description on the basis of exemplary embodiments illustrated in the drawings. The drawing, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into further meaningful combinations. The same reference symbols in the figures designate the same elements.

• 1 ein Ausführungsbeispiel eines erfindungsgemäßen Systems umfassend einen ersten Gegenstand und einen Referenzgegenstand;
• 2 ein zweites Ausführungsbeispiel eines erfindungsgemäßen Systems umfassend einen ersten Gegenstand und einen Referenzgegenstand
• 3 ein Verfahrensdiagramm zu einer exemplarischen Ausführungsform des erfindungsgemäßen Verfahrens zum Ermitteln einer relativen Position;
• 4 ein exemplarisches Magnetfeld, wie es beispielhaft von einer Magnetfelderzeugungsvorrichtung eines Referenzgegenstands erzeugt wird;
• 5a-5f unterschiedliche Szenarien, wie das erfindungsgemäße Verfahren angewandt werden kann;
• 6 zeitabhängige Verläufe von Magnetfeldsignalen (a) zu einem beispielhaften System (b).

Show it:

• 1 an embodiment of a system according to the invention comprising a first object and a reference object;
• 2 a second embodiment of a system according to the invention comprising a first object and a reference object
• 3 a process diagram for an exemplary embodiment of the method according to the invention for determining a relative position;
• 4 an exemplary magnetic field exemplarily generated by a magnetic field generating device of a reference object;
• 5a-5f different scenarios of how the method according to the invention can be applied;
• 6 time-dependent curves of magnetic field signals (a) to an exemplary system (b).

Description of the exemplary embodiments

The method according to the invention relates to determining a relative position P of a first object 100 with respect to at least one reference object 200. In 1 and 2 two exemplary systems 300a, 300b are shown, each comprising a first object 100a, 100b, at least one reference object 200a, 200b and an evaluation device 302. The evaluation device 302 is set up to carry out the method 10 according to the invention, cf. 3 , to execute.

This in 1 The system 300, 300a shown shows a perspective view of a first object 100, 100a, which is implemented as a hand-held electrical device, here as a laser range finder. The laser range finder has a housing, a display 104 and actuating elements 106 for switching the laser range finder on and off and for starting or configuring a measuring process. During a measurement process, the laser range finder emits laser radiation 110. Such laser range finders are known from the prior art. The position of the first object 100, 100a in three-dimensional space - indicated here by the bidirectional arrow, which represents free mobility of the laser range finder - is determined according to the method 10 according to the invention as a relative position P with respect to at least one reference object 200, 200a. The reference object 200, 200a is stationary, for example placed on the floor of the room to be measured. The reference object 200, 200a comprises a magnetic field generating device 202 for generating at least three directional magnetic fields B1, B2, B3 (cf. 3 , method step 16 as well as 4 , reference numeral 210) with distinguishable modulation frequencies f1, f2, f3. The magnetic field generating device 202 comprises three emitter coils Tx1, Tx2, Tx3 with reference numbers 204a, 204b, 204c, which are mutually orthogonally aligned. The first object 100, 100a has a magnetic field detection device 112 for detecting magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| and modulation frequencies f1, f2, f3 of the three magnetic fields B1, B2, B3. The magnetic field detection device 112 includes three magnetic field sensors 114a, 114b, 114c, which are embodied here as Hall sensors, each having a sensitivity that is aligned orthogonally to one another. Furthermore, the system 300, 300a, here the first object 100, 100a, has an evaluation device 302 which, in order to determine the relative position P of the first object 100, 100a with respect to the reference object 200, 200a, includes the method step of determining the relative position P (cf . 3 , method step 24) executes. Depending on the determined relative position P, a function of the laser range finder is controlled, for example the implementation and/or allocation of a range measurement.

This in 2 The system 300, 300b shown shows a perspective view of a first object 100, 100b, which is implemented as a robot, here an autonomous lawn mower or an autonomous vacuum cleaner. The autonomous lawn mower has a housing 102 . Such autonomous lawn mowers are known from the prior art. The position of the first object 100, 100a in three-dimensional space - also indicated here by the bidirectional arrow, which represents free mobility of the autonomous lawnmower - is determined according to the method 10 according to the invention as a relative position P with respect to at least one reference object 200, 200b. The reference object 200, 200b is implemented as a docking station (base station) of the autonomous lawn mower and is placed in a fixed position on the floor of the work area to be worked on. The reference object 200, 200b includes a magnetic field generating device 202 for generating at least three directional magnetic fields B1, B2, B3 (cf. 3 , method step 16 as well as 4 , reference numeral 210) with distinguishable modulation frequencies f1, f2, f3. The magnetic field generation with distinguishable modulation frequencies f1, f2, f3. For this purpose, the magnetic field generating device 202 comprises three emitter coils Tx1, Tx2, Tx3 (reference numerals 204a, 204b, 204c), which are mutually orthogonally aligned. The first object 100, 100b has three magnetic field detection devices 112a, 112b, 112c. Each of the three magnetic field detection devices i - reference numbers 112a, 112b, 112c - is for detecting magnetic field strengths |Bx _i (P)|, |By _i (P)|, |Bz _i (P)| and modulation frequencies f1, f2, f3 of the three magnetic fields B1, B2, B3 and comprises three receiver coils, not shown here, which are implemented as RF coils. The three magnetic field detection devices 112a, 112b, 112c, in particular the receiver coils contained therein, each have a defined arrangement relative to one another. Here, three receiver coils are aligned in parallel in pairs, with the three pairs of three each being aligned orthogonally to one another are If the robot is in the immediate vicinity of the docking station, it is charged using at least one emitter coil (here, for example 204b) of magnetic field generating device 202, in that energy is inductively transmitted from the emitter coil to at least one receiver coil, thereby inductively charging an energy storage device of the robot will. Furthermore, the first object 100, 100b also has a wireless communication device 116, which is used for communication between the first object 100, 100b and the evaluation device 302. In this system 300, 300b, the evaluation device 302 is implemented in a separate unit, for example in a cloud, which, to determine the relative position P of the first object 100, 100b with respect to the reference object 200, 200b, at least includes the method step of determining the relative position P (see. 3 , method step 24) executes. The evaluation device 302 is also set up for wireless communication (cf. radio symbol on the box) with the first object 100, 100b and the reference object 200, 200b. Furthermore, the first object 100, 100b has an odometry sensor 120a as a further internal sensor device 120, which detects a movement of the wheels 118 and from this determines further position data to increase the precision (cf. 3 , method step 24a). The odometry sensor 120a also serves as a rotation-sensitive sensor device 122, by means of which a change in the direction of movement, in particular a reversal of the direction of movement by 180°, of the first object 100, 100b can be detected. The reference object 200, 200b also has a further position sensor designed as a GPS sensor, which is not shown in detail here. Depending on the determined relative position P, a function of the robot is controlled, for example the navigation of the robot or the processing of the work area to be processed.

3 shows an exemplary embodiment of the method 10 according to the invention. The method 10 is used to determine a relative position P of a first object 100, 100a, 100b--for example the in 1 laser range finder shown or the in 2 shown robot - to be determined with respect to at least one reference object 200, 200a, 200b.

In a first optional method step 12, the presence of at least one magnetic field BSQ of an external radiation source, in particular a magnetic field generating device 202 not assigned to the reference object 200, 200a, 200b, is first detected. The presence of the first object 100, 100a, 100b by means of the magnetic field detection device 202 and/or by means of the magnetic field generating device 202 assigned to the reference object 200, 200a, 200b is detected. The detection includes the determination of a modulation frequency fSQ of the magnetic field BSQ and the detection of pause times in the generation TSQ of the magnetic field BSQ. Depending on this determined modulation frequency(s) fSQ and pause times in the generation TSQ of the magnetic field BSQ, both the modulation frequencies f1, f2, f3 and pause times in the generation T1, T2, T3 of the magnetic fields B1, B2, B3 are adjusted. The pause times in the generation T1, T2, T3 of the magnetic fields B1, B2, B3 are selected such that the magnetic fields B1, B2, B3 are generated during the pause times in the generation TSQ of the magnetic field BSQ. Furthermore, the frequencies f1, f2, f3 are selected in such a way that they are different from the modulation frequency fSQ.

Furthermore, in the first optional method step 12, an influence of an interference field on the first object 100, 100a, 100b is detected (which can later be used in method step 16 to compensate for the interference field).

In a further optional method step 14, the modulation frequencies f1, f2, f3 (possibly selected or modified in method step 12) are transmitted from the magnetic field generating device 202 of the reference object 200, 200a, 200b to the magnetic field detection device 112 of the first object 100, 100a, 100b by means of the wireless Communication link (implemented here as a radio link) and used as a reference signal of a lock-in amplifier (not shown here) of the magnetic field detection device 112, so that in method step 20 there is a significant improvement in a signal-to-noise ratio when determining the magnetic field strengths |Bx(P) |, |By(P)|, |Bz(P)| and consequently the relative position P is realizable.

In method step 16, three directional magnetic fields B1, B2, B3 (cf. 4 , reference numeral 210) with the (possibly previously modified) distinguishable modulation frequencies f1, f2, f3 using the magnetic field generating device 202 of the reference object 200, 200a, 200b and transmitted.

In optional method step 18, the influence of the interference field previously determined in optional method step 12 is used to compensate for this by controlling and/or regulating an electromagnetic superimposed field emitted by at least one compensation coil (not shown). In particular, the emission of the heterodyne field during the detection of the magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| maintained in step 20.

In method step 20, magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| and modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3 are detected at the point in space where the first object 100, 100a, 100b is located at that time.

In optional method step 22, magnetic field strengths |Bx _2.3 (P)|, |By _2.3 (P)|, |Bz _2.3 (P)| and modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3 are detected, which can later be used in the optional sub-method step 24b for evaluation.

In method step 24, the relative position P of the first object 100, 100a, 100b with respect to the at least one reference object 200, 200a, 200b is determined by means of the evaluation device 302 of the system 300, 300a, 300b from the detected modulation frequencies f1, f2, f3 magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)|, which can be assigned to the directed magnetic fields B1, B2, B3. This can be done on the one hand by mathematical calculation, on the other hand by comparing the detected magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| with a magnetic card. In this exemplary embodiment, a combination of both variants is used to increase the precision. The expected magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| deposited. This magnetic field map can, for example, have been created initially and can be continuously updated (cf. sub-method step 24c) in order to be able to take into account the effects of temporary interference fields in particular. The determination of the relative position in method step 24 also includes the transmission of the required measurement data to the evaluation device 302.

In the optional sub-method step 24a, when determining the relative position P, further position data are recorded, such as those recorded with the internal sensor device 120 in the form of the odometry sensor 120a (cf. 2 ), included to increase the precision by using this additional position data for a comparison of the relative positions obtained by the method according to the invention. In this case, for example, a method for detecting outliers can be used, as is shown in DE 102017213577.8 A1 is known. Furthermore, in the embodiment of 2 the reference object 200, 200b in the form of the docking station has a GPS sensor, by means of which the determined relative position of the first object 100, 100b can be converted into an absolute position.

In the optional sub-method step 24b, a relation of the magnetic field strengths in the form of a magnetic field gradient as a component-by-component difference |Bx _i (P)| - |Bx(P)|, |By _i (P)| - |By(P)| or |Bz _i (P)| - |Bz(P)| determined, where i=2.3 characterizes the values of the further magnetic field detection device 112, 112b, 112c. The values that are provided by receiver coils aligned in parallel are subtracted in each case. In this case, an unambiguous identification of the relative position P to a quadrant of the magnetic field is carried out on the basis of a sign of the relation. At the same time, a change in the direction of movement, in particular a reversal of the direction of movement by 180°, of the first object 100, 100b is detected by means of the rotation-sensitive sensor device 122 in the form of the odometry sensor 120a “ multiplied).

In the optional sub-method step 24c, when the first object 100, 100b is moved to detect magnetic field distortions, deviations in the relation from the expected target according to the defined arrangement of the magnetic field detection device 112, 112a and the two additional magnetic field detection devices 112, 112b, 112c (i=2, 3). -Relations evaluated. These deviations indicate corresponding magnetic field distortions or the influence of interference fields. If detected, these magnetic field distortions are stored in the magnetic field map by updating it or by merging the values already contained with the new ones.

In optional sub-method step 24d, system information encoded jointly in each modulation frequency f1, f2, f3 of the magnetic fields B1, B2, B3 and/or in all of the modulation frequencies f1, f2, f3 is then decoded by the evaluation device 302.

Finally, in method step 26, at least the determined relative position P, optionally the absolute position calculated therefrom and optionally the decoded system information are provided at an output of the evaluation device 302 for further use or processing.

In 4 An exemplary magnetic field 210 is shown, as is generated in one plane by two mutually orthogonal emitter coils 204a, 204c of a magnetic field generating device 202 of a reference object 200, 200a, 200b. The magnetic field is divided into four quadrants Q1, Q2, Q3, Q4, in each of which - neglecting magnetic field distortions - symmetrically equal magnetic field strengths are present, for example at the four points 206 drawn as examples. In order to enable a one-to-one assignment of the relative position P to one of the quadrants, the first item 100, 100b - here the robot in the form of the autonomous lawn mower 2 - three magnetic field detection devices 112a, 112b, 112c, which are arranged under a defined arrangement to each other. Here the connecting lines of the two rear magnetic field detection devices 112b, 112c are perpendicular to the connecting lines of the two magnetic field detection devices 112a, 112c, the latter connecting line being parallel or collinear to the direction of travel of the robot (represented by an arrow). For simplification, it is assumed that the magnetic field amount of the magnetic field is considered as an example for the magnetic field B1 (here, for example, generated by the emitter coil 204a)—whereby all other fields are blanked out. All three magnetic field detection devices 112a, 112b, 112c measure the x, y and z components of this magnetic field B1 (denoted by |Bx _i ^B1 (P)|, |By _i ^B1 (P)|, |Bz _i ^B1 ( P) | and i=1,2,3), from which the amount of the magnetic field acting at the respective location of the magnetic field detection device 112a, 112b, 112c is formed. If the robot now moves in the direction of a quadrant boundary 208, the detected magnetic field strength |Bx(P)| drops (of the magnetic field B1) first on the first magnetic field detection device 112a, followed by the two further magnetic field detection devices 112b, 112c. We have |Bx ₂ ^B1 (P)| - |Bx ^B1 (P)| > 0, |Bx ₃ ^B1 (P)| - |Bx ^B1 (P)| > 0, where the subscripts 2, 3 stand for the two magnetic field detection devices 112b, 112c (the subscript for i=1 has been omitted).

If the robot now moves beyond the quadrant boundary 208, the detected magnetic field strength initially increases at the first magnetic field detection device 112a, while the magnetic field strength detected by the two further magnetic field detection devices 112b, 112c continues to decrease. From a certain point |Bx ₂ ^B1 (P)| holds - |Bx(P)| < 0, |Bx ₃ ^B1 (P)| - |Bx(P)| < 0, so that by reversing the sign of the relations |Bx ₂ ^B1 (P)| - |Bx(P)| or |Bx ₃ ^B1 (P)| - |Bx(P)| a transition into another quadrant can be concluded. If the starting position of the first object 100, 100b is known, a clear assignment of the relative position P can always be achieved despite the ambiguity of the magnetic field 210. A change in the direction of movement, in particular a reversal of the direction of movement by 180°, of the robot is also detected by means of the rotation-sensitive sensor. If the robot reverses its direction of movement, the sign reversal of the relations is taken into account by the fact that the relation |Bx ₂ ^B1 (P)| - |Bx(P)| or |Bx ₃ ^B1 (P)| - |Bx(P)| is multiplied by "-1".

Magnetic field distortions can also be detected remotely using the three magnetic field detection devices 112a, 112b, 112c. Due to the known alignment, in particular also the known distances, of the magnetic field detection device 112a, 112b, 112c, a comparison of the relation of expected target relations according to the defined arrangement of the magnetic field detection devices 112a, 112b, 112c can be evaluated. If the measured and expected values deviate from one another, a magnetic field distortion can be concluded. As described, such detected magnetic field distortions can be stored in the magnetic field map (cf. 3 optional sub-process step 24c).

In 5a until 5f different scenarios are shown how the method 10 according to the invention can be applied. In 5a will - by analogy with 1 or 2 - A relative position P of a first object 100 with respect to a reference object 200 is determined. The first object 100 is freely movable, the reference object 200 is stationary. In 5b will - analogous to 5a - only the relative relation (of the position P) reversed. A relative position P of the reference object 200 with respect to the first object 100 is determined here. In this case, the first object 100 is stationary, while the reference object 200 is freely movable. Furthermore, it is also possible to keep the first object 100 freely movable while the reference object 200 is stationary. In 5c the relative position P of the first object 100 is determined, in particular optionally, with respect to a plurality of reference objects 200. In this case, each reference object 200 has an associated magnetic field generating device 202 . In 5d on the other hand, a relative position P of a plurality of first objects 100 is determined, in particular optionally, with respect to at least one reference object 200. In 5e a sequential determination of relative positions is proposed. In analogy to 5a a relative position of a first object 100 with respect to a reference object 200 is determined. Furthermore, a relative position P′ of the reference object 200 with respect to at least one further reference object 200 is determined. Nested constellations are also conceivable, as shown in 5f is shown. Here, the relative positions P of two first objects 100 with respect to two further first objects 100 are determined, with all first objects 100 also being reference objects 200 at the same time. In this way, relative positions P′ of at least two first objects are in turn related to a further one Reference object 200c determined. In this way, for example, a swarm of robots can navigate autonomously, in that each robot can generate and receive a magnetic field itself. This enables the robots to be localized relative to one another. This localization can be used as a basis for joint path planning.

Depending on previously determined magnetic fields BSQ - which are given here by the magnetic fields of the other robots - the modulation frequencies f1, f2, f3 and pause times in the generation T1, T2, T3 of the magnetic fields B1, B2, B3 are adjusted (cf. 3 , optional process step 12). In particular, the modulation frequencies f1, f2, f3 of each reference object 200 are selected in such a way that they differ sufficiently from the modulation frequencies fSQ of the other reference objects 200—here the other robots. Furthermore, the pause times in the generation T1, T2, T3 of the magnetic fields B1, B2, B3 are selected in such a way that the generation of the magnetic fields B1, B2, B3 in the respective pause times in the generation TSQ of the magnetic fields (TSQ = set of all other pause times of the remaining magnetic fields) of the remaining reference objects 200 takes place. In this way, on the one hand, the range of the method for determining the relative position P of the first object 100 can be increased and, on the other hand, parallel operation of several methods according to the invention can be made possible.

For the constellation of 6b (compare to 5f) is in 6a shown how the frequencies f1 to f15 and pause times in the generation of the magnetic fields, here TDS (= docking station), TR1 to TR4, are adapted to one another in such a way that no frequencies occur twice and that each reference object 200 has pause times for the other reference objects 200 sends.

QUOTES INCLUDED IN DESCRIPTION

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

Patent Literature Cited

• DE 102017214314 A1 [0002]
• US 4737794 A1 [0004]
• DE 102014219550 A1 [0016]
• DE 102016211742 A1 [0048]
• DE 102018201692 A1 [0048]
• DE 102014226077 A1 [0050]
• DE 102017213577 A1 [0072]

Claims (10)

Method (10) for determining a relative position P of a first object (100, 100a, 100b) with respect to at least one reference object (200, 200a, 200b), comprising: • Generation of at least three directional magnetic fields B1, B2, B3 with distinguishable modulation frequencies f1, f2, f3 by means of a magnetic field generating device (202) assigned to the reference object (200, 200a, 200b), the magnetic field generating device (202) having at least three emitter coils Tx1, Tx2, Tx3 includes, which alternately have a defined arrangement to each other, • Detection of magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)| and modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3 by means of a magnetic field detection device (112, 112a) of the first object (100, 100a, 100b), • Determination of the relative position P of the first object (100, 100a, 100b) with respect to the at least one reference object (200, 200a, 200b) by means of an evaluation device (302) from the detected magnetic fields detected via the detected modulation frequencies f1, f2, f3 B1, B2, B3 assignable magnetic field strengths |Bx(P)|, |By(P)|, |Bz(P)|. Method (10) according to claim 1 , wherein in a further method step the presence of at least one magnetic field BSQ of an external radiation source, in particular a magnetic field generating device (202) not assigned to the reference object (200, 200a, 200b), is detected. Method (10) according to claim 2 , wherein the presence of the at least one magnetic field BSQ is detected by means of the magnetic field detection device (112, 112a) of the first object (100, 100a, 100b) and/or by means of the magnetic field generation device (202) assigned to the reference object (200, 200a, 200b) and/or by means at least one additional receiver is detected. Method (10) according to any one of claims 2 - 3 , the modulation frequencies f1, f2, f3 and/or pause times in the modulation T1, T2, T3 and/or pause times in the generation T1, T2, T3 of the magnetic fields B1, B2, B3 being selected depending on the presence of the at least one magnetic field BSQ , modified in particular, are. Method (10) according to claim 4 , wherein the detection comprises determining a modulation frequency fSQ of the at least one magnetic field BSQ and wherein the modulation frequencies f1, f2, f3 of the magnetic fields B1, B2, B3 are chosen to be different from the modulation frequency fSQ. Method (10) according to any one of Claims 4 - 5 , wherein the detection comprises a determination of pause times in the modulation tSQ and/or pause times in the generation TSQ of the at least one magnetic field BSQ and wherein the pause times in the modulation T1, T2, T3 and/or the pause times in the generation T1, T2, T3 of the magnetic fields B1, B2, B3 are selected in such a way that the modulation of the magnetic fields B1, B2, B3 in the pause times in the modulation tSQ and/or the generation of the magnetic fields B1, B2, B3 in the pause times in the generation TSQ of the at least a magnetic field BSQ takes place. Method (10) according to any one of claims 2 - 6 , wherein the magnetic field BSQ of the external radiation source, in particular the magnetic field generating device (202) not assigned to the reference object (200, 200a, 200b), is used to extend the range of the method for determining the relative position P of the first object (100, 100a, 100b ) to enlarge. Method (10) according to any one of claims 2 - 7 , wherein the magnetic field BSQ of the external radiation source, in particular of the magnetic field generating device (202) not assigned to the reference object (200, 200a, 200b), originates from a parallel-operated method (10) according to one of the preceding claims. System comprising a first object (100, 100a, 100b), at least one reference object (200, 200a, 200b) and an evaluation device (302), characterized in that the system, in particular the evaluation device (302), is set up to use a method (10) according to any of the preceding Claims 1 until 8th to execute. First item (100, 100a, 100b) and/or reference item (200, 200a, 200b) for use in a system according to claim 9 .

Images