Method for determining a position in process automation

Abstract

The present invention relates to a method (400) for determining the position of an object by means of a sensor, comprising: a step (402) of setting a local sensor coordinate system; a step (404) of setting a global target coordinate system; a step (406) of determining transformation parameters for transforming coordinates in the local sensor coordinate system into coordinates in the global target coordinate system; a step (408) of acquiring local coordinates of the position of the object; and a step (410) of transforming the position of the object into coordinates in the global target coordinate system.

Description

Technical Field

[0001] The present invention relates to a method for determining the position of an object by means of a sensor, a computing unit, a sensor, a system having a computing unit and a sensor, and the use of the computing unit in a process automation, factory automation system or in a multi-sensor environment having a plurality of position-variable sensors. Background Art

[0002] Two-dimensional measurement radar systems can be used for global monitoring in the field of safety or automation technology. In addition, line-scan two-dimensional radar systems for conveyor belts are known, which detect the amount of loose material transported on the conveyor belt. The common feature of the above systems is that the position of objects in the monitoring area is determined based on their distance and their angular position relative to the sensor itself, which is also sufficient to solve a large number of problems. Three-dimensional measurement systems, especially for level measurement technology, are also known. In such a system, a radar signal is applied to a layer of loose material in a container or on a heap of loose material stored outdoors, and the topology of the surface of the loose material is calculated based on the reflection of the radar signal on the medium. Through known transformations, the volume of the loose material can be accurately determined from this topology, and in the case of a known density, the mass of the loose material can also be accurately determined.

[0003] For example, sensors for process or factory automation determine the distance and angular position related to the respective position of the corresponding sensor. Thus, a radar sensor, for example, determines the distance to the filling material as the distance between a reference point (zero point) located in the sensor and the surface of the filling material. In addition to the distance value, sensors for process and factory automation can also determine the angle value between the sensor and the corresponding reflector. These angle values are also specified in a manner related to an existing plane or mark ("sensor reference plane") on the sensor itself. The disadvantage of the above method is that service technicians cannot know the position or orientation of the filling material or object from the outside. Summary of the Invention

[0004] The object of the present invention is to provide a method and a system that overcome this defect.

[0005] The described embodiments similarly relate to a method for determining the position of an object by means of a sensor, a computing unit, a sensor, a system having a computing unit and a sensor, and the use of the computing unit in a process automation or factory automation system or in a multi-sensor environment having a plurality of position-variable sensors. Synergistic effects can be produced by various combinations of the embodiments, although they may not be described in detail.

[0006] Those skilled in the art can understand and implement other variations of the disclosed embodiments when studying the drawings, the disclosure, and the appended claims in practicing the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single processor or other unit can implement the functions of multiple subjects or steps recited in the claims. The fact that specific measures are recited in mutually dependent claims does not mean that combinations of these measures cannot be used advantageously.

[0007] According to a first aspect, there is provided a method for determining the position of an object by a sensor. The method includes the following steps: setting (i.e., specifying) a local sensor coordinate system; setting a global target coordinate system; determining transformation parameters for transforming coordinates in the local sensor coordinate system into coordinates in the global target coordinate system; obtaining local coordinates of the position of the object; and transforming the position of the object into coordinates in the global target coordinate system.

[0008] Therefore, a method is proposed in which a multi-dimensional measurement sensor such as a radar sensor detects, for example, the direction relative to an object and the distance from the object, and is given a position in the global coordinate system. Thus, the service technician can know the position where the object is located without knowing the orientation of the sensor.

[0009] The term "sensor" is known, for example, to those skilled in the art of process automation. Depending on the type and design, such a sensor may, for example, include an antenna, a detector for measuring variables, electronics for mirror amplification, processing, and possibly digitization of the detected signals, a power supply unit, an interface for the outside, and an energy storage. The listed components should only be understood as examples. A sensor is usually mounted in a housing. Thus, other units (e.g., other sensors) can also be integrated into the sensor. To distinguish these other sensors (e.g., acceleration sensors) mentioned in the present invention, these other sensors are referred to as "additional sensors".

[0010] The "object" is, for example, an undesired material accumulation on the container wall, or, for example, a loose material for which its distribution in the container should be determined and observed. Since, for example, from the perspective of a radar sensor, radar waves are reflected on the object, in the examples of the present invention, the term "reflection point" generally refers to the object, or more precisely, to the position of the object. In addition, the object should also be understood as, for example, a loose material that has a topology detectable by a sensor due to being placed in a container.

[0011] The term "position" generally refers to complete coordinates, while the term "orientation" generally describes a direction or an orientation. Depending on the context, the orientation can be the orientation of an object or the orientation relative to the sensor orientation in space. For example, the position of an object can be determined in a spherical coordinate system by adding a distance to the orientation information associated with the spherical coordinate system.

[0012] The term "local" refers to the sensor. On the other hand, the term "global" refers to a potentially large but still limited area, such as typically an industrial facility. In some embodiments, the defining component of the global coordinate system is the direction of gravity. Thus, if the origin of the coordinate system is not the intersection of different gravity directions (e.g., the geocentric coordinate system), the geographical extent of the area should be limited to the range within which the direction of gravity can still be considered "the same" for the purposes of the present invention. Otherwise, for example, the global geodetic coordinate system can be used as the global coordinate system.

[0013] The orientation is initially related to the local sensor coordinate system, which will be described in more detail in the following embodiments. For example, the local sensor coordinate system is not always known to the service technician. If, for example, the position in the local coordinate system is communicated to the technician, it must also be ensured that the position does not change, for example, due to movement, before the technician arrives. Especially in a system with a large number of sensors, the technician still needs to reorient each sensor. By remotely transmitting the coordinates of an object in the global target coordinate system, the position of the object can be provided to the technician at a remote service center or at a remote location, for example, in the form of a graphical representation on a smartphone, a computing device, or a paper printout, and can also be displayed on-site. Thereby, the service is significantly easier, faster, and less error-prone, and thus also more economical. Here, the evaluation of the coordinates in the unified transmission system is not complicated.

[0014] The target coordinate system is not necessarily the final coordinate system. The object coordinates can continue to be transformed into one or more other coordinate systems.

[0015] According to one embodiment, the local coordinate system is a spherical coordinate system or a Cartesian coordinate system, and the step of setting the local coordinate system includes defining the sensor plane as the equatorial plane or the xy plane, defining the center of the sensor plane as the origin of the coordinate system, and defining a reference point outside the sensor plane as the reference direction or as the direction in which one of the axes in the sensor plane points from the origin towards the reference point.

[0016] Thus, the local sensor coordinate system is, for example, a spherical coordinate system, whose polar axis is the main direction, for example, the central transmitting and receiving direction of the antenna of the radar sensor. The polar axis is, for example, perpendicular to the lower side or lower surface of the sensor. Here, the lower side or lower surface is, for example, parallel to the surface of the container where the sensor is mounted. This surface (also referred to as the sensor plane in the present invention) can serve as the equatorial plane. The origin or center point of the coordinate system is, for example, the center point of the sensor plane restricted to the area of the sensor. The reference direction of the azimuth angle can be, for example, a mark on the sensor plane or the outlet point of the cable in the sensor plane. For example, in the case of a Cartesian sensor coordinate system, if the origin is the same, the azimuth reference direction will correspond to the x-axis, and the pole direction will correspond to the z-axis, and the y-direction will be derived accordingly. The basic sensor coordinate system is advantageously selected according to the characteristics of the sensor. If the sensor is, for example, a radar sensor for measuring distance and direction, it is preferably a spherical coordinate system. Since from the perspective of those skilled in the art, the transformation from the local spherical coordinate system to the corresponding Cartesian coordinate system is an insignificant issue, and further methods do not need to distinguish between them, the specific naming of the two coordinate systems is basically omitted hereinafter. Therefore, by specifying information such as elevation, azimuth, and distance, in the case of these corresponding local coordinate systems, those skilled in the art can read the Cartesian equivalents, such as the slopes in the x and y directions and / or the xyz coordinates, etc.

[0017] According to one embodiment, the step of obtaining the local coordinates of the position of the object includes determining the elevation angle and the azimuth angle with respect to the reference direction of the local sensor coordinate system. The elevation angle is the inclination with respect to the equatorial plane of the sensor spherical coordinate system, and the azimuth angle is the rotation with respect to the reference direction. The distance is also necessary for position determination. The distance is measured by the sensor itself and is thus easily determined. If the local sensor coordinate system and the global target coordinate system have the same origin, the distance remains unchanged and thus no translation is required. To transform to the target coordinate system, it is first advantageous to transform the spherical coordinates into the Cartesian coordinates of the local Cartesian coordinate system.

[0018] According to another embodiment, the global target coordinate system is a Cartesian coordinate system or a geodetic coordinate system. The orientation of one of the axes of the Cartesian coordinate system is in the compass direction, and the orientation of the other axis is in the gravity direction. Preferably, the compass direction is, for example, the south or north direction. By selecting the gravity direction as one of the axes, it allows the use of sensors based on gravity and other methods described below. The advantage of a geodetic coordinate system such as WGS84 is that it is not locally restricted and some satellite navigation systems use this system. However, this conversion is relatively complex.

[0019] According to another embodiment, the plane determined by the direction of gravity as the normal is located at a height associated with the container. In other words, the direction of gravity as the normal vector defines a set of planes. One of the planes is selected, and this plane is located at a suitably chosen height of the container, for example, at or near the bottom of the container.

[0020] According to another embodiment, the transformation parameter is the elevation angle, and the elevation angle is obtained by one or more of the following methods: The first method includes detecting the elevation angle by a protractor or by an elevation angle measurement sensor of a smartphone. The second method includes detecting the elevation angle by an inclination and / or acceleration sensor in the sensor. The third method includes detecting the falling direction of the loose material during the filling process as the direction of gravity and determining the elevation angle based on the direction of gravity. The fourth method includes detecting the direction of the flat surface of the container wall as the direction of gravity and determining the elevation angle based on the direction of gravity. Here, the flat surface refers to, for example, the vertical wall of a rectangular or cylindrical container. If the local coordinate system is a spherical coordinate system, the transformation can be performed as described above, that is, transformed into the local Cartesian coordinate system in an intermediate step and then transformed into the Cartesian target coordinate system accordingly. However, the elevation angle mentioned in this embodiment should not be confused with the elevation angle of an object relative to the local sensor spherical coordinate system. The elevation angle of this embodiment refers to the relationship between the local sensor system and the global coordinate system to determine the value of the transformation parameter elevation angle, such as the inclination of the pole direction relative to the direction of gravity. Here, the orientation of the sensor or the local coordinate system is related to the global coordinate system. The orientation of the sensor can be determined by an additional sensor in the sensor that can be used to detect the inclination relative to the direction of gravity, or can be determined by an additional sensor located in the smartphone when the smartphone is tilted according to the orientation or pole direction of the sensor or the local sensor spherical coordinate system. The elevation angle can also be determined optically, for example, by the falling direction of a medium such as loose material.

[0021] According to one embodiment, another transformation parameter is the azimuth angle or azimuth, and at least one of the transformation parameters elevation angle and azimuth angle is obtained by one or more of the following methods: In the first method, an image of the sensor and the markings of the sensor is taken with a smartphone or a smartphone camera, and based on this, the reference direction of the local coordinate system is determined; and the compass direction is determined by measuring the Earth's magnetic field with a smartphone compass, and finally the azimuth angle is determined based on the compass direction and the reference direction. In the second method, the smartphone has additional sensors that can measure tilt (i.e., the elevation angle relative to the direction of gravity) and additional sensors that can measure the azimuth angle. For example, the additional sensor (e.g., a gyroscope) can detect how many degrees the smartphone has rotated in order to move from the marked direction to the south direction. In this case, the smartphone does not have to actively rotate, but can include a function to automatically determine the offset of, for example, the south direction relative to the current orientation. Another method is to detect the container shape by scanning the container and use the facility layout plans (Anlageplans) for displaying the container orientation and the container shape to determine the elevation angle and the azimuth angle. Thus, an external (i.e., global) reference is obtained here via the facility layout plan. For example, the facility layout plan can be stored in a database or memory so that it can be automatically accessed and used.

[0022] In other words, according to this embodiment, the azimuth angle is determined individually, or the azimuth angle and the elevation angle are determined simultaneously. For the azimuth angle, for example, the magnetic orientation of, for example, a compass needle can be optically compared or measured with the line from the origin to the marking or the key point (i.e., the reference direction).

[0023] According to one embodiment, the additional sensors in the sensor are one or more of the following devices: a compass, a satellite navigation receiver, an acceleration sensor, an astronomical observation unit including at least an optical detection unit, a date detection unit, and a time detection unit. The global orientation can also be determined by the antenna device of a GPS receiver or by an acceleration sensor. Another possible method is based on the astronomical observation unit. For example, the position of the sun can be determined. For example, the position of the sun at sunset at a specific date and specific time can be calculated, and the azimuth angle can be obtained from the simple difference between this position and the reference direction of the local terrestrial coordinate system.

[0024] According to one embodiment, the coordinates in the target coordinate system are further transformed into a user-defined coordinate system by user-defined translation parameters. For example, the axes have the same orientation, but the origin is set, for example, at a point such as the center of the bottom plane of a container. Thus, the user-defined coordinate system can be another sensor-specific coordinate system with the global coordinate system orientation. Thus, the service technician can immediately identify the container with the container information or the sensor ID and also identify the position of the object. In this case, he does not have to determine the container or the sensor by global coordinates, for example, according to the layout plan.

[0025] According to one embodiment, the origin of the user-defined coordinate system is at the bottom of the container, for example at the center of the bottom plane. However, the origin can also be defined at a corner point or a top point. Another suitable point is the origin of the local coordinate system. If the origin of the target coordinate system is not set at another point in space, this will correspond to a translation of 0. In this case, the target coordinate system and the user-defined coordinate system are the same.

[0026] According to one embodiment, the method further includes the step of transmitting the coordinates of the object in the target coordinate system or the user-defined coordinate system to the data acquisition unit via an interface.

[0027] The coordinates can be stored locally and transmitted on-site to a smartphone, tablet, or service device, for example, via NFC (Near Field Communication). However, these coordinates can also be transmitted to a server, evaluation unit, or cloud via a wired or wireless connection using a fieldbus, an Ethernet / Internet connection, or a mobile radio connection.

[0028] Furthermore, measured, determined, and / or configured values, parameters, and data such as transformation parameters, image data, GPS data, radar sensor measurement data, geometric data of the facility or container, etc. can be sent to the server, evaluation unit, or cloud so that these steps can be partially or fully executed in the sensor, server, evaluation unit, and / or cloud service. The corresponding wireless or wired transmission paths (especially the transmission paths for process automation) and the corresponding interfaces are known to those skilled in the art and will not be further explained here.

[0029] According to another aspect, there is provided a computing unit that includes a program element for instructing the computing unit to perform the steps of the method. For example, the computing unit can be arranged in a server or an evaluation unit, and / or as a server in the cloud. This means that the computing unit can also be a logical unit physically distributed over multiple units (e.g., different hardware units).

[0030] According to another aspect, there is provided a sensor having such a computing unit. The sensor is, for example, a radar sensor, a laser sensor, an ultrasonic sensor, or a similar sensor that can be used to measure distance and direction. Here, "sensor" can also be understood as a sensor group, and the sensor group interacts with each other as one such sensor. In this case, for example, one sensor in the sensor group can be used as the sensor that serves as a reference for the local coordinate system.

[0031] According to another aspect, a system is provided that includes a computing unit and a sensor for determining the position of an object in a local coordinate system. As described above, the sensor can also be a sensor group. The computing unit can be the processing unit as described above, which transforms the determined position or coordinates in the local coordinate system into coordinates in a global or user-defined coordinate system.

[0032] Therefore, a multi-dimensional measurement radar system is proposed that provides at least two spatial coordinates respectively characterizing the reflection points. Here, the spatial coordinates are fixedly related to a globally fixed point and / or a user-specified fixed point.

[0033] According to another aspect, the use of the computing unit in process automation, factory automation, or a multi-sensor environment with multiple position-variable sensors is provided.

[0034] Therefore, by using the system and method described above, the multi-dimensional measurement radar system can provide the azimuths of a large number of reflection points to the outside. Therefore, the data set for describing the multiple reflection points can be transmitted and applied to remote facilities such as a control room or the cloud effectively, either wired or wirelessly. In order to be able to display, evaluate, and correctly interpret the transmitted data of a large number of measurement points in a unified form, the positions of the transmitted reflection points can be associated with a globally determinable reference position independent of the sensor installation position, and / or refer to it. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Exemplary embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The description and the drawings should not be construed as limiting the present invention.

[0036] Figure 1 A schematic diagram of a system with a container and a sensor in a two-dimensional coordinate system is shown.

[0037] Figure 2 A schematic diagram of a system with a container and a sensor in a three-dimensional coordinate system according to an embodiment is shown.

[0038] Figure 3 A schematic diagram of a system with multiple containers and sensors in a three-dimensional coordinate system according to an embodiment is shown.

[0039] Figure 4 A flowchart of a method according to an embodiment is shown.

[0040] Figure 5 A block diagram of a system according to an embodiment is shown.

[0041] The drawings are only schematic and are not drawn to scale. In principle, the same or similar components are provided with the same reference numerals. DETAILED DESCRIPTION

[0042] Figure 1 First, a one-dimensional measuring radar sensor 101 is shown. In particular, the sensor 101 determines the distance d1 105 between its sensor reference plane 102 or its internal zero point 102 and the surface 103 of the medium 104 to be measured according to the time-of-flight method (Laufzeitverfahren). In the shown arrangement, the determined measured value d1 105 is independent of the possibly torsionally performed installation 106 of the sensor. In other words, the measurement is independent of the installation torsion angle 106 of the sensor. However, it is possible for the user to adjust the sensor reference point 102 by specifying a constant correction term for application. In particular, it is possible for the user to set the measured value output by the measuring device 101 in a way related to a freely selectable reference point 108, and the reference point 108 usually corresponds to the elevation of the container bottom 109. By additionally specifying the container height h 110, the sensor 101 can continuously provide the filling level l 111, or in other words, can continuously provide the elevation of the surface 103 of the medium 104 relative to the reference height B 108 as a derived value as the measured value.

[0043] The inclination of the sensor 101, in particular the inclination of the sensor reference plane 102, can be automatically determined by a position sensor integrated in the sensor, and by using trigonometric functions, the vertical distance between the surface 103 and the sensor 101 can be automatically determined from the determined inclined distance. Even in the case of an inclined installation, the torsion 106 of the sensor 101 in its axial direction has no influence on the measured value and is therefore not evaluated either.

[0044] Figure 2 An example of a multi-dimensional measuring device or sensor 201 is shown, here an example of a three-dimensional radar sensor 201 for detecting the topology of the surface 202 of a bulk material. In one

[0045] example, the sensor is also designed to externally provide the positions of the individual reflection points 203 in the container 204. Referring Figure 1 to the embodiment, the multi-dimensional measuring radar sensor 201 includes a sensor reference plane 205 or an internal zero point 205, and the distance values d 206 from the sensor reference plane 205 or the internal zero point 205 to the individual reflectors 203 within the detection range of the sensor 201 are determined. In the case of a two-dimensional radar sensor, the orientation of the reflector 203 is also characterized by a first angular offset phi 207 with respect to the surface normal of the plane E, and the plane E is defined by the sensor reference plane 205 (e.g., the mounting flange). Without limiting generality, it can be assumed here that the 0° direction of the first angular position 207 is defined as perpendicular to the reference plane 205. However, other initial directions can also be selected. [[ID=!7]]

[0046] In this example of a three-dimensional radar sensor, a second angular offset theta perpendicular to the first offset angle phi 207 is typically identified as being parallel to the plane E 205, and by specifying spherical coordinates with the origin of the spherical coordinates located at the center of the sensor reference plane 205, the second angular offset, together with the other coordinates, characterizes the position of the reflector 203. The definition of the second offset angle theta 208 requires setting the 0° direction within the sensor 201, where, at this point, for example, the direction 208 in which the connecting cable 209 exits the sensor housing can be used. However, other settings for the theta = 0° direction are also possible and can be made externally visible, for example, by means of a graphic marking on the sensor housing.

[0047] In a typical processing step, the identified polar or spherical coordinates are transformed into Cartesian sensor coordinates 210, thereby clearly defining the orientation of each reflector 203 relative to the sensor 203. It is particularly advantageous but by no means restrictive to assume in the following that the transformation takes place in such a way that the plane spanned by the coordinate axes Xs 211 and Ys 212 is parallel to or identical to the sensor reference plane 205, and the Xs axis extends in the direction of theta = 0°.

[0048] In the next useful method step, the positions of the individual reflectors 203 can be transformed into a coordinate system 213 that can be specified by the respective user. Here, the coordinate system 213 can be freely chosen by the user to a large extent. In a large number of applications, the directions of the axes XR, YR, ZR, 214, 215, 216 correspond to the directions of our normal overall perception, i.e., the plane spanned by the axes XR 214 and YR 215 corresponds to the horizontal plane, and the ZR axis 216 extends along the direction of gravity as the surface normal of the horizontal plane. The origin 217 of the coordinate system is usually a point defined near or at the center of the container 204, the elevation of which corresponds to the elevation of the surface of the filling material in a container that is almost completely emptied (see also Figure 1 ).

[0049] If the coordinate system 213 (herein referred to as the "global coordinate system") is selected to output the positions of the respective reflectors 203, and the origin of this coordinate system 213 can also be located, for example, at the elevation of the sensor 201 and at the center of the reference plane 205 in the delivered state of the sensor, then when the tilt angles of the sensor 201 caused by its mounting position in two directions are available, the transformation of the coordinates of this point from the coordinate system 210 of the sensor 201 can be carried out largely automatically. In one embodiment, after installation is completed, the tilt of the reference plane 205 can be measured with a measuring device (e.g., a protractor or a smartphone) and communicated to the sensor 201 via an interface. Alternatively, at least one tilt angle of the reference plane 205 (which corresponds to the planes Xs 211, Ys 212) relative to the horizontal plane or relative to the vertical can also be automatically detected by a tilt sensor or an acceleration sensor integrated in the sensor 201. During operation of the sensor 201, the vertical can also be detected based on the falling direction of the loose material during the filling process, or the direction of a flat surface such as usually defined by the container wall can be interpreted as the vertical.

[0050] However, the previous embodiments and disclosures are not sufficient to reliably transform the sensor coordinates 210 of the reflector 203 into easily interpretable global coordinates 213. By using the tilt angle of the reference plane 205 provided in the sensor 201 according to one of the above exemplary embodiments, the sensor coordinate system 210 and all the coordinates of each reflector determined thereby can be made "horizontal and vertical", that is, it can be achieved that the plane spanned by the transformed coordinate axes Xs' and Ys' is parallel to the planes XR 214 and YR 215 of the finally to be achieved global coordinate system 213. Since only the tilt of the reference plane 205 is considered and not the torsion 218 of the sensor 201 relative to the container 204 and thus also relative to the global coordinate system 213, significant defects will occur here. Therefore, in addition to the tilt of the reference plane 205, the torsion 218 of the sensor 201 relative to a globally determinable fixed point located outside the sensor 201 can be made known and thus evaluable in the sensor 201 itself. Thus, in one embodiment, when the sensor 201 is put into operation, the determination of the torsion 218 relative to the fixed coordinate system can be provided by user input. However, the disadvantage of this solution is that during the transportation of the container 204, this torsion may change, especially relative to the fixed reference direction outside the container 204, between the individual measurement cycles. Therefore, the torsion 218 can also be detected by an external measuring device and transmitted to the sensor 201 via a known communication channel. In particular, the sensor 218 can be photographed with a smartphone, and the deviation of the 0° direction 208 of the sensor 201 relative to a globally available reference point (e.g., the South Pole) can be determined by using, for example, a compass integrated in the smartphone and the corresponding image processing performed for locating the marking or the cable outlet 209. It is also conceivable that the smartphone can be oriented by means of a corresponding marking attached to the sensor 201, so that the smartphone can determine the tilt and the torsion 218 of the plane 205 and transmit them to the sensor 201. In a particularly advantageous embodiment, the torsion 218 and / or the tilt of the sensor 201 relative to a globally available fixed point can also be automatically determined, in particular by a fixed point determination device integrated in the sensor 201, which is, for example, a compass, a GPS, an acceleration sensor, an astronomical observation unit (e.g., a camera for detecting sunrise and sunset with time and date), or, in the case of adding a layout plan for indicating the orientation and shape of the container, by a container scan for detecting the shape of the container, and used to transform the coordinates of a specific reflection point 203 from the sensor coordinate system 210 to the global coordinate system 213.

[0051] For example, the global coordinate system 213 used by the user can always be oriented such that the XR axis 214 faces south. However, other orientations more suitable for the corresponding application can also be selected. However, it should be noted at this point that the selection of different orientations represents a static transformation from the global coordinate system 213 to another user coordinate system Bx, which can be performed by specifying a fixed offset in the translation direction and / or the rotation direction once according to a known method.

[0052] Figure 3 This again illustrates the special advantages of the present invention when operating a large number of sensors in the system. The containers 301, 302 belonging to the system and the open-air loose material pile 303 are each equipped with multi-dimensional measurement radar sensors 304, 305, 306. The sensors 304, 305, 306 are significantly different from each other not only in terms of the inclination of their respective sensor reference planes (e.g., mounting flanges), but also in terms of their respective torsions 218 at their respective measurement points 301, 302, 303. Therefore, the coordinate systems 307, 308, 309 of the sensors themselves are also significantly different from each other. If the basic idea of the present invention is not applied, the positions of the individual reflectors 203, 310 or the orientation of the topology of the loose material surface 311 can only be determined relative to their own sensor electronics in these sensors. If these values are transmitted to the central evaluation and visualization device, no conclusion can be drawn about, for example, on which container wall in the containers 301, 302 the caking 203, 310 occurs without knowing exactly the respective installation conditions of the sensors (i.e., the inclination angle of the reference plane, the torsion angle, and, if necessary, the installation height). Therefore, a basic effect of the present invention is to achieve unified processing of coordinates regardless of the respective installation positions of the sensors 201. For this purpose, in an exemplary embodiment, the coordinates of at least one determined reflection point related to the sensor coordinate systems 307, 308, 309 are transformed into a sensor-independent global coordinate system 312, 213 in consideration of the pre-determinable and / or independently determinable information about the installation conditions (i.e., the inclination angle of the reference plane, the torsion angle, and, if necessary, the installation height). For example, the XR axis of the coordinate system 312 can be oriented in the south direction, and the ZR axis can be oriented along the vertical direction, based on which these two directions can be determined at any point in the world.

[0053] The zero point (i.e., the origin of the coordinate system 312) can also be globally and clearly defined. For example, similar to according to Figure 1In the known process of sensor 106, the zero point of coordinate system 312 is directly defined at the center of the reference plane of the respective sensors 304, 305, 306. However, a uniform altitude reference (e.g., sea level) independent of the respective applications can also be used. The determination of the absolute altitude of the sensors relative to the uniform, globally available elevation can be globalized by user input or automatically by sensors integrated in the sensors (referred to as additional sensors in the present invention) and / or external additional sensors communicatively connected to the sensors.

[0054] The most important element of the transformation from sensor coordinates 210 to global coordinates 213 is that the torsion and / or inclination of sensors 304, 305, 306 can be eliminated by this first transformation, so that the values provided by the sensors are unambiguous with respect to the orientation of the coordinate axes XR, YR, ZR and independent of their respective installation conditions.

[0055] In an optional further or combined method step, similar to Figure 1 the process, for example, by inputting the container height and / or specifying the offsets on the X-axis and Y-axis, the user can change the origin of the global coordinate system 312 used by each sensor for the sensor to output values according to his needs. In this way, user-defined coordinate systems B1, 313; B2, 314; B3, 315 are created for each of the containers 301, 302, 303. In most cases, the coordinate systems B1, 313; B2, 314; B3, 315 are determined such that the origin of each coordinate system is located at the bottom center of each container, and at the same time, the X-axis is oriented, for example, in the south direction, and the Z-axis is oriented along the vertical line. If the caking at point P with defined Xp, Yp and Zp coordinates is now output by the respective sensors as measurement values related to the user-specified coordinate system, the service technician on the container site can very easily and unambiguously obtain the position of the corresponding reflection point by using a compass or a smart phone. Especially when the orientation of the existing containers with respect to the compass direction is known from the facility layout plan, it is now also possible to simply and uniformly perform parallel display and joint evaluation of the topology of a large number of loose materials in a facility with a large number of different containers and orientations.

[0056] Figure 4 Method 400 for determining the position of an object by means of sensors is shown. In a first step 402, a local sensor coordinate system is set. In a second step 404, which can also occur before or simultaneously with step 402, a global target coordinate system is set. In a further step 406, transformation parameters for transforming the coordinates in the local sensor coordinate system into the coordinates in the global target coordinate system are determined. In the next step 408, the local coordinates of the position of the object are acquired, and in step 410, the position of the object is transformed into the coordinates in the global target coordinate system.

[0057] Figure 5 A block diagram of system 500 is shown, which includes sensor 201 described herein and computational unit 502 that performs transformations described herein. System 500 or computational unit 502, for example, has an interface for cloud 504. Cloud 504 can include, for example, servers and / or storage units that cache coordinates. In this example, data acquisition unit 506 can obtain data or coordinates from the server, further graphically process them, for example, and provide them to the service technician in a suitable form. Here, the coordinates of objects 203, 310, 311 are also transmitted, for example, in the same target coordinate systems 213, 312 to other sensors 201' in system 500, or in user-defined coordinate systems (313, 314, 315) to each sensor 201, 201'.

[0058] The above exemplary embodiments relate to applications from the field of process automation. However, the principles and embodiments of the present invention can also be applied in an obvious manner to those skilled in the art to sensors in the fields of factory automation or safety technology for general monitoring of areas with a large number of sensors and a large number of installation situations. It may also be particularly advantageous here not to provide the orientation of each reflector related to the installation situation of the sensor, but to provide (at least partially) the position related to a globally determinable fixed point.

[0059] It should also be considered in the context of the present invention that the transformation of the coordinates determined by the sensor to global coordinates can be performed in the sensor itself or in the evaluation unit or in the cloud. In addition to the measurement data, the sensor can also output information about its installation situation (for example, the tilt angle, rotation angle of the reference plane, and optionally the installation height). The evaluation unit or the cloud system can also obtain this information from a database or an installation situation detection unit (for example, a camera on site).

[0060] The exemplary embodiments shown above mainly use the Cartesian coordinate system. In the context of the present invention, in an obvious manner to those skilled in the art, other coordinate systems such as polar coordinate systems or spherical coordinate systems can also be used to implement the present invention. In particular, a system with geographical longitude and latitude information can also be used.

Claims

1. A method (400) for determining the position of an object (203, 310, 311) in a container by sensors (201, 304, 305, 306), comprising: a step (402) of setting a local sensor coordinate system (210, 307, 308, 309); a step (404) of setting a global target coordinate system (213, 312); a step (406) of determining transformation parameters for transforming coordinates in the local sensor coordinate system (210, 307, 308, 309) into coordinates in the global target coordinate system (213, 312); a step (408) of obtaining local coordinates of the position of the object (203, 310, 311); a step (410) of transforming the position of the object (203, 310, 311) into coordinates in the global target coordinate system (213, 312); wherein, the local sensor coordinate system (210, 307, 308, 309) is a spherical coordinate system or a Cartesian coordinate system, and wherein the step (402) of setting the local sensor coordinate system (210, 307, 308, 309) includes defining a sensor plane (205) as an equatorial plane or an xy plane, defining the center of the sensor plane (205) restricted within the area of the sensor as the origin of the local sensor coordinate system (210, 307, 308, 309), and defining a reference point outside the sensor plane (205) restricted within the area of the sensor as a reference direction or as the direction of one of the axes in the sensor plane (205) from the origin towards the reference point; the step (408) of obtaining local coordinates of the position of the object includes: determining an elevation angle and an azimuth angle with respect to the reference direction of the local sensor coordinate system (210, 307, 308, 309); and wherein the transformation parameter is an elevation angle, and the elevation angle is obtained by one or more of the following methods: detecting the elevation angle by a protractor outside the sensor or by an additional sensor for elevation angle measurement of a smartphone outside the sensor; detecting the elevation angle by an inclination and / or acceleration sensor in the sensor; if the container is filled with loose material, detecting the falling direction of the loose material during the filling process as the direction of gravity by an additional sensor, and determining the elevation angle based on the direction of gravity; detecting the direction of the surface of the container wall as the direction of gravity, and determining the elevation angle based on the direction of gravity.

2. The method (400) according to claim 1, wherein The global target coordinate system (213, 312) is a Cartesian coordinate system or a geodetic coordinate system, and the orientation of one of the axes of the Cartesian coordinate system is in the compass direction, and the orientation of one of its other axes is in the direction of gravity.

3. The method (400) according to claim 1, wherein, The xy plane determined by the direction of gravity as the normal of the global target coordinate system (213, 312) is at a height related to the container.

4. The method (400) according to claim 1, wherein Another of the transformation parameters is the azimuth angle, and at least one of the elevation angle and the azimuth angle as the transformation parameter is obtained by one or more of the following methods: Taking an image of the sensor (201, 304, 305, 306) and the marker of the sensor with a smartphone, determining the reference direction based on the image, determining the compass direction by measuring the earth's magnetic field with the smartphone compass, and determining the azimuth angle based on the compass direction and the reference direction; Aligning the smartphone with the corresponding marker attached to the sensor, and detecting the elevation angle and the azimuth angle with an additional sensor of the smartphone; Detecting the shape of the container by scanning the container, and using a facility layout diagram showing the orientation of the container and the shape of the container to determine the elevation angle and the azimuth angle.

5. The method (400) according to claim 4, wherein, The additional sensor in the sensor (201, 304, 305, 306) is one or more of the following devices: a compass, a GPS receiver, an acceleration sensor, and an astronomical observation unit including at least one of an optical detection unit, a date detection unit, and a time detection unit.

6. The method (400) according to claim 1, wherein, Further transforming the coordinates in the global target coordinate system (213, 312) to the user-defined coordinate system (313, 314, 315) by a user-defined translation parameter.

7. The method (400) according to claim 6, wherein, The origin of the user-defined coordinate system (313, 314, 315) is located at the bottom of the container (301, 302, 303).

8. The method (400) according to claim 6, wherein, The method (400) further includes the following steps: Transmitting the coordinates of the object (203, 310, 311) in the global target coordinate system (213, 312) or the user-defined coordinate system (313, 314, 315) to the data acquisition unit (506) via an interface.

9. A computing unit (502) including program elements, the program elements instructing the computing unit (502) to perform the steps in the method (400) according to any one of claims 1 to 8.

10. A sensor (201, 304, 305, 306) including the computing unit (502) according to claim 9.

11. A system (500) including the computing unit (502) according to claim 9 and a sensor (201, 304, 305, 306) for determining the position of an object (203, 310, 311) in a container in a local sensor coordinate system (201, 307, 308, 309).

12. The system according to claim 11, further including a smartphone external to the sensor and / or a protractor external to the sensor having an additional sensor for elevation angle measurement, which is arranged to detect the elevation angle by the additional sensor of the smartphone or the protractor.

13. Use of the computing unit (502) according to claim 9 in the system (500) according to claim 11 in process automation or factory automation or in a multi-sensor environment with multiple position-variable sensors.

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