DEVICE FOR MONITORING THE POSITION OF AN OBJECT BY MEANS OF SOUND WAVES

Abstract

A device for monitoring the local orientation or position of an object by sound waves, with a sensor part positioned at a distance from the object with at least one sound wave emitter, at least one sound wave receiver, and a computing unit. The computing unit controls the at sound wave emitter and the sound wave receiver and determines the distance between the sensor part and the object, based on the echoes of a sound wave emitted by the sound wave emitter in the direction of the object. An identification reflector separate from the sensor part comprises a three-dimensional pattern. The sensor part has an array of sound wave receivers and sound wave emitters, wherein for identifying the identification reflector and for measuring the distance between the sensor part and the identification reflector, a plurality of echoes between different emitter/receiver-combinations is evaluated.

Claims

1. A device for monitoring the position of an object and a distance of the object from a sound wave emitter, by using sound waves, comprising: a sensor comprising an array of a plurality of sound waive receivers and a plurality of sound wave emitters; a computing unit connected to and controlling the plurality of sound wave emitters and the plurality of sound wave receivers, the computing unit configured for determining the distance between the sensor and the object, based on a plurality of echoes of a sound waves emitted by the plurality of sound wave emitters in a direction of the object; and an identification reflector, which is separate from the sensor and which comprises a three-dimensional pattern; wherein in order to identify the identification reflector and to measure the distance between the sensor and the identification reflector, the plurality of echoes between different combinations of the plurality of sound wave emitters and plurality of sound wave receivers is evaluated.

2. The device of claim 1, wherein the computing unit is configured for activating, in a time sequence, different combinations of sound wave emitter and sound waive receiver pairs comprised of the plurality of sound waive emitters and sound wave receivers and evaluate corresponding echoes of the plurality of echoes.

3. The device of claim 1, wherein the three-dimensional pattern comprises a plurality of discrete geometric forms spaced from each other, which have at least one of different cross-sections or different heights.

4. The device of claim 3, wherein the plurality of geometric forms are arranged on a support.

5. The device of claim 3, wherein the plurality of geometric forms comprise at least two bodies.

6. The device of claim 1, wherein the plurality of sound wave emitters and the plurality of sound wave receivers are positioned relative to each other according to a defined arrangement.

7. The device of claim 1, wherein the plurality of sound wave emitters and the plurality of wave receivers are arranged on a circuit board.

8. The device of claim 2, wherein the computing unit is configured for activating, in a temporally offset way, the different combinations of sound wave emitter and sound waive receiver pairs.

9. The device of claim 1, wherein a number of possible different combinations of the plurality of sound wave emitters and the plurality of sound waive receivers is greater than 5.

10. The device of claim 1, wherein the plurality of sound wave receivers and the plurality of sound wave emitters are arranged in substantially a same plane.

11. The device of claim 1, wherein the plurality of sound wave receivers and the plurality of sound wave emitters are arranged in different planes.

12. The device of claim 1, wherein the distance between the sensor and the object is between 0.5 mm and 100 m.

13. The device of claim 1, wherein the identification reflector is mounted inside a sound-permeable, waterproof enclosure.

14. The device of claim 1, wherein the object to be monitored is a movable device.

15. The device of claim 1, wherein the computing unit is configured for activating the plurality of sound wave emitters in a phase-shifted time sequence.

16. A method for monitoring the location of an object by using sound waves, comprising: a generating a plurality of sound waves with a plurality of sound wave emitters; and detecting the plurality of sound waves reflected by an object with a plurality of sound wave receivers in order to measure at least a distance between a sensor and the object based on a plurality of echoes of the sound waves reflected from the object positioning an identification reflector on the object; and evaluating the plurality of echoes between different pairs of the plurality of sound wave emitters and the plurality of sound wave receivers to determine at least a distance between the plurality of sound wave emitters and the object.

17. The method of claim 17, further comprising using the identification reflector, wherein the identification reflector comprises a three-dimensional pattern having two or more discrete geometric forms.

18. The method of claim 17 further comprising recording echoes of different combinations of the plurality of sound wave emitters and the plurality of sound wave receivers, the plurality of sound wave emitters and the plurality of sound wave receivers positioned according to a defined arrangement to each other.

19. The method of claim 17, further comprising, evaluating echoes of different combinations of the plurality of sound wave emitters and the plurality of sound wave receivers in a time sequence.

20. The method of claim 19, further comprising reconstructing the three-dimensional pattern of the identification reflector based on the echoes of the different combinations of the plurality of sound wave emitters and the plurality of sound wave receivers.

21. The method of claim 20, further comprising, comparing the reconstructed pattern of the identification reflector to one or more stored reference patterns.

22. The method of claim 21 further comprising activating an alarm or switching an output of the sensor if a difference between the reconstructed pattern of the identification reflector and the one or more stored reference patterns is detected.

23. The method of claim 16, further comprising modulating the emitted sound waves with an additional signal to perform a noise suppression.

24. The method of claim 16, wherein when the identification reflector is positively detected, processes are validated or performed, comprising at least one of a detection of an empty material stack drawer or a safe identification of a certain automatic material supply within a technical production process.

25. The method of claim 16, further comprising detecting objects or persons within a protection area between the identification reflector and the sensor.

26. The method of claim 1, wherein the sensor comprises a door contact switch of a safety door for protecting an automatically operating technical installation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Exemplary embodiments of the invention are now described in further detail with reference to the following figures. In particular:

[0036] FIG. 1 schematically shows an exemplary embodiment of the invention with a device for monitoring the position of an object with a sensor part and an identification reflector;

[0037] FIG. 2 schematically shows a first exemplary embodiment of the sensor part of FIG. 1 with a control part and an array of sound wave receivers and a single sound wave emitter;

[0038] FIG. 3 schematically shows a first exemplary embodiment of the sensor part of FIG. 1 with a control part and an array of sound wave emitters and a single sound wave receiver;

[0039] FIG. 4 schematically shows a third exemplary embodiment of a circular array of three sound wave receivers and 37 sound wave emitters; FIG. 1 without enclosure;

[0040] FIG. 5 schematically shows a fourth exemplary embodiment of an array of one sound wave receiver and 36 sound wave emitters in a hexagon;

[0041] FIG. 6 schematically shows a fifth exemplary embodiment of an array of a respective equal number of sound wave receivers and sound wave emitters, wherein sound wave emitters and sound wave receivers are respectively positioned in a plane and in a staggered succession;

[0042] FIG. 7 schematically shows an exemplary embodiment of the identification reflector of FIG. 1 without an enclosure;

[0043] FIG. 8 shows the identification reflector of FIG. 7 with an enclosure, which is partially cut out for clarity;

[0044] FIG. 9 shows an illustrative example of the invention with a line-by-line arrangement of four sound wave emitters and one simple identification reflector provided at a distance from the emitter array for explaining the phased-array technology;

[0045] FIG. 10 shows the shortest paths of sound waves of the example of FIG. 9;

[0046] FIG. 11 illustratively shows the inventive evaluation method based on the echo reflected by an identification reflector; and

[0047] FIG. 12 shows an inventive device for monitoring a double door with an emitter part and two sound wave receivers.

DETAILED DESCRIPTION OF THE INVENTION

[0048] FIG. 1 schematically shows an example of an inventive device 11 for monitoring the location or position of an object by using sound waves. The device 11 comprises a computing unit 13 and an array 15 of sound wave emitters 17 and sound wave receivers 19. The computing unit 13 is connected with the individual sound wave emitters 17 and sound wave receivers 19 and may selectively control the same and evaluate the signals recorded by the sound wave receivers 19. The computing unit 13 is provided with an output 21, through which a signal, such as an alarm, may be output. The inventive device 11 also comprises an identification reflector 23, which is positioned at a distance from the sensor part 13 and on an object 25 to be monitored (see FIG. 7). In operation, the sound wave emitters 17 emit sound waves 27, which are partially reflected by the identification reflector 23 and recorded by the sound wave receivers 19.

[0049] Based on the travel time of sound waves 27, it is possible to precisely calculate the distance between emitter 17 and identification reflector 25 with a given medium and corresponding temporal resolution. If the distance between the sensor part 23 and the identification reflector 23 is changed, a signal may be output by output 21.

[0050] As illustratively shown in FIGS. 2 to 6, both the ratio between sound wave emitters and sound wave receivers and their mutual geometric arrangement may be different. It is however to be noted that the resolution of the inventive device is higher and more precise, the larger the number of sound wave emitters and sound wave receivers used.

[0051] The example of FIG. 2 is characterized in that only a single sound wave emitter 17 and a plurality of sound wave receivers 19 are used. The sound wave emitter 17 and the sound wave receivers 19 in the example shown are placed according to a matrix, wherein the only emitter 17 is positioned at the center of the 55 matrix array.

[0052] The exemplary embodiment of FIG. 3 differs from the one of FIG. 2 in that a single sound wave receiver 19 and a plurality of sound wave emitters 17 are provided. The receiver 19 is at the center of the array and the sound wave emitters 17 are grouped around the receiver 19.

[0053] In the example of FIG. 4, the sound wave emitters 17 and sound wave receivers 19 are arranged on three circles around a central sound wave emitter S20. Three sound wave receivers R1 to R3 on the middle circle form the corner points of an imaginary equilateral triangle. A plurality of sound wave emitters is in a circular arrangement.

[0054] In the example of FIG. 5, the sound wave emitters S1 to S37 are arranged according to a hexagon, wherein at the center of the hexagon the sound wave receiver R1 is positioned.

[0055] In the example of FIG. 6, the number of sound wave emitters used and the number of sound wave receivers used is the same, wherein the sound wave emitters S1 to S27 are positioned in a first location 27 and the sound wave receivers R1 to R27 are positioned in a second location 29 behind the sound wave emitters. However, it may also be conceived that sound wave emitters and sound wave receivers are alternatingly and adjacently positioned in the same location.

[0056] In FIG. 7 an identification reflector 23 is shown in greater detail. The identification reflector 23 has a support 31, on which a plurality of geometric bodies or forms 33 are positioned at a distance from each other. At least individual geometric forms 33 have a different height and a different cross-section. According to the example shown, the geometric forms are parallelepipeds, which are positioned on the support 31. The identification reflector 23 may comprise an enclosure 35, which is at least partially transparent to sound waves (FIG. 8). This allows the use of the inventive device also in polluted environments or installations, which have to be washed.

[0057] FIG. 9 shows, as an explanation of the measurement concept, an array of four sound wave emitters U1 to U4 and one identification reflector 23, which is at a distance from the sound wave emitters. The identification reflector 23 is formed by a flat reflector part 37 and a parallelepiped 39, positioned on the left side of the reflector part, which protrudes beyond the reflector part 37 in the direction of the sound wave emitters U1 to U4. The sound wave emitters U1 to U4 are activated, in a time sequence, after a time period t.sub.seq and emit sound waves 40. As shown in FIG. 10, d.sub.1 is the shortest distance between the emitter U.sub.1 and the anterior front face 41 of parallelepiped, d.sub.2 is the shortest distance between the emitter U.sub.2 and the anterior front face 41 of parallelepiped, and d.sub.3 or d.sub.4 are the respective shortest distances between emitters U.sub.3 and U.sub.4 and the reflector part 37.

[0058] Those skilled in the art will recognize that with a corresponding high number of temporally successive echo measurements between different pairs of sound wave emitters and sound wave receivers, the spatial structure of the identification reflector may be resolved, so that a unique association to a certain reflector part is possible. It is also conceivable that the sound waves are additionally modulated for delimitation with respect to other possible interfering noises.

[0059] In FIG. 11 a simple example is shown, where the paths of the sound waves emitted by a single emitter differ from each other, according to which form 33 of the reflector part has reflected the sound wave 27. Thus, the distance of the sound wave emitter 17 from the form having the number 1 and position coordinates (X1, Y1) is 5 cm, from form having number 2 and position coordinates (X2, Y1) 4 cm, from form having number 3 and position coordinates (X1, Y2) 3 cm and from form having number 4 and position coordinates (X2, Y2) 2 cm. In the following table 1, the different distances between the sound wave emitter 17 and the identification reflector 23 are summarized:

TABLE-US-00001 Array X position 1 X position 2 Y position 1 5 cm 4 cm Y position 2 3 cm 2 cm

[0060] In contrast, the distances between an identification reflector 23a, as shown in the upper side on the right, would be as follows:

TABLE-US-00002 Array X position 1 X position 2 Y position 1 3 cm 5 cm Y position 2 5 cm 3 cm

[0061] The corresponding distances between an identification reflector 23b, as shown in the lower part on the right, would be as follows:

TABLE-US-00003 Array X position 1 X position 2 Y position 1 4 cm 3 cm Y position 2 2 cm 5 cm

[0062] Since the measured distances only correspond with the central identification reflector 23 shown on the right side, whose pattern is stored in the memory of the computing unit, the identification reflector 23 is thus univocally identifiable.

[0063] FIG. 12 shows how the inventive device may be used for monitoring an object 25, in this case a double door made of two door wings 43a, 43b, which may be rotated around swing axes 45a, 45b. In this case, a sensor part 11 forms, together with two sound wave receivers 23, a monitoring device for both wings 43a, 43b of the double door. The open position of the door wings is shown by a dashed line in FIG. 12.

[0064] The inventive method may be implemented by any of the arrays of sound wave emitters and sound wave receivers shown in FIGS. 2 to 6. It is only to be noted that the number of sound wave emitters and sound wave receivers and their mutual distances are sufficient, in combination with a certain identification reflector and the distance between the sensor part and the identification reflector, for obtaining the required resolution for a univocal identification of the identification reflector.

[0065] Conclusion: Based on the echo of a plurality of different sound wave emitter/sound wave receiver combinations the pattern of the three-dimensional identification reflector is reconstructed.