LIGHT GRID WITH DISTANCE MEASUREMENT

Description

[0001] The invention relates to a light grid for object detection.

[0002] Light grids are known from the prior art. These comprise a transmitter strip and a receiver strip, forming a grid of light beams for object detection between them. In particular, one or both strips of the light grid can be attached to the sliding door(s) of an elevator car to detect the passage of an object through the open door area. CN 111 273 371 A describes a detection system with a light grid.

[0003] The object of the invention is to provide a light grid that enables more differentiated monitoring at low cost.

[0004] This object is achieved, starting from a light grid of the type mentioned above, by a light grid according to claim 1. Advantageous embodiments are specified in the further dependent claims.

[0005] The light grid according to the invention is a light grid for determining the distance between transmitter and receiver bars, comprising a transmitter bar with one or more transmitter elements which emit radiation with a specific intensity, a receiver bar with one or more receiver elements which receive the radiation of an associated transmitter element, and a control device for controlling the transmitter elements and / or the receiver elements and for evaluating the receiver elements, wherein the transmitter element and the receiver element or at least one of the transmitter elements and / or at least one of the receiver elements are designed as qualified transmitter and receiver elements, wherein the qualified transmitter element or the qualified transmitter elements are designed to emit different intensities and / or the qualified receiver element or the qualified receiver elements are designed toto apply different amplifications and to output an intensity value for the received and amplified radiation, and the control device is designed to control different combinations of intensities and amplifications of the qualified transmitter and / or receiver elements and to determine a distance value depending on the sum of the resulting intensity values ​​of the controlled combinations.

[0006] This can offer the advantage of determining the distance between the transmitter and receiver bars. At the same time, dynamic processes can be easily tracked and analyzed. The grid, in turn, does not compromise any safety requirements.

[0007] Preferably, the light grid, in particular the transmitter and receiver strip, has at least one or more further transmitter and receiver elements, which are each designed as simple transmitter elements and simple receiver elements and which are each designed as a light barrier and which preferably do not contribute to the combinations and / or from which the distance value is not determined, and / or which are used for object detection, and / or whose simple transmitter elements emit at least one intensity like the qualified transmitter elements and whose receiver elements have at least one amplification like the qualified receiver elements.

[0008] This can provide the advantage that the light grid can be used for object detection. This can provide the advantage that not all transmitter and receiver elements need to be designed with high-quality components, thus reducing the complexity of the light grid and saving costs. However, such an embodiment of the invention also enables a compromise between precise object detection and a cost advantage, which arises from the fact that not all transmitter and receiver elements need to be equipped with the same functions; rather, individual elements can be equipped with fewer functions at lower cost.

[0009] According to the invention, the control device is designed to control the combinations sequentially in a sequence and, in particular, to repeat the sequence periodically and, in particular, to determine the sum of the controlled combinations of a sequence and, in particular, to determine a distance value for each sequence. Preferably, the control device is designed to control all different combinations of intensities and amplifications of the qualified transmitter and / or receiver elements, in particular, however, without using the highest intensity of the qualified transmitter elements for the combinations, and / or to use those intensities and amplifications of the qualified transmitter and receiver elements for object detection that correspond to the intensities and amplifications of simple (unqualified) transmitter and / or receiver elements.

[0010] This can offer the advantages of a fixed time period after which the distance value is available, of the distance value being determined repeatedly and quasi-continuously, and of the distance value being available dynamically in a temporal sequence. This can offer the advantages of calculating the distance value quickly and easily. This can offer the advantage of achieving maximum resolution or accuracy for the distance value. This can offer the advantage that the number of transmitter and receiver elements required for object detection does not need to be increased by the qualified transmitter and receiver elements.

[0011] Preferably, the one or more qualified transmitter elements are designed to each individually emit a plurality of different intensities, and / or to emit intensities that are different from one another, and / or to each emit the same intensity, which is in particular the highest intensity and in particular corresponds to the intensity of the non-qualified transmitter elements.

[0012] This can offer the advantage of providing optimized intensities for different distance ranges, increasing the resolution of the distance value, and ensuring that the resolution of the distance value remains consistently constant across the entire distance range. This can also offer the advantage that the qualified transmitter elements can also be used for object detection.

[0013] Preferably, the one or more qualified receiver elements are designed to each individually apply a plurality of different amplifications, and / or to apply the same different amplifications, and / or to each apply an identical amplification, which is in particular the highest and in particular corresponds to the amplification of the unqualified, ie simple, receiver elements.

[0014] This can provide the advantage of optimized gains for different distance ranges, increasing the resolution of the distance value, and ensuring that the resolution of the distance value remains consistently constant across the entire distance range. This can also provide the advantage that the qualified receiver elements can also be used for object detection.

[0015] The light grid preferably has three qualified transmitter and receiver elements each, as well as further simple transmitter and receiver elements which do not contribute to the combinations and / or from which the distance value is not determined. The one or more qualified transmitter elements are preferably designed to each emit three intensities, wherein one intensity is the same as the intensity of the unqualified, i.e. simple, transmitter elements which are provided for object detection, and wherein two intensities lower than the one are the same and each differ from all other intensities. The one or more qualified receiver elements are preferably designed to each apply the same two different amplifications, wherein the higher amplification corresponds to the amplification of the unqualified, i.e. simple, receiver elements which are provided for object detection.Preferably, the control device is configured to form twelve combinations of the three qualified transmitter and receiver elements, the two overall different, lower intensities of the qualified transmitter elements, and the two different, each identical, gains of the receiver elements. Preferably, the control device is configured to use those intensities and gains of the qualified transmitter and receiver elements for object detection that correspond to the intensities and gains of unqualified, i.e., simple transmitter and / or receiver elements.

[0016] This can have the advantage of providing a very fine resolution for the distance value.

[0017] Preferably, the light grid has a transmitting device which is designed to transmit the distance value wirelessly.

[0018] This can have the advantage that the behavior of the car door can be transmitted and evaluated without interfering with the elevator's control and electronics.

[0019] Further features of the invention are set forth in the drawings.

[0020] The advantages mentioned can also be realized for combinations of features in which they are not mentioned. Overview of the drawings:

[0021] Embodiments of the invention are illustrated in the drawings and explained in more detail below. Like reference numerals in the individual figures denote corresponding elements. They show: Fig. 1 Light grid Fig. 2a Opened double sliding door of an elevator car with light grid Fig. 2b Half-open double sliding door like Fig. 2a Fig. 2c Closed double sliding door like Fig. 2a Fig. 3 Diagram of a measurement curve Fig. 4 Diagram with all measurement curves Fig. 5 Distance value diagram Detailed description of the drawings:

[0022] Fig. 1shows a light grid 20 according to the invention with the transmitter strip 21 and the receiver strip 22. The transmitter strip 21 has three qualified transmitter elements 31 and further non-qualified transmitter elements 33, which can emit IR radiation with a specific intensity. The receiver strip 22 has three qualified receiver elements 32 and further non-qualified receiver elements 34. The transmitter strip and receiver strip are each arranged perpendicularly and parallel to one another and opposite one another at the same height. Each qualified transmitter element 31 is assigned a qualified receiver element 32 at the same height, and together they form a horizontal transmitter beam 30. The light grid 20 also has a control device 35.

[0023] Fig. 2a to 2c show the light grid 20 of the Fig. 1on a double sliding door 10 of an elevator car. The transmitter bar 31 is attached to one wing of the double sliding door, and the receiver bar 32 is attached to the opposite wing of the double sliding door. The remaining arrangement is as shown in Fig. 1 The transmitter bar 31 and receiver bar move with the double sliding doors, remaining parallel and level with each other, so that the light beams remain horizontal and directed to the corresponding qualified transmitter and receiver elements. They decrease their distance with the doors when the doors close, and they increase their distance with the doors when the doors open. The distance between the transmitter and receiver bars corresponds to the distance between the two leaves of the double sliding door, up to a constant factor. Fig. 2a shows the open door. Fig. 2b shows the half-closed door. Fig. 2c shows the closed door.

[0024] The unqualified transmitter elements transmit with the intensity Tx:High, and the unqualified receiver elements have the two gains Rx:High and Rx:Low. Rx:Low is lower than Rx:High. The gains are applied simultaneously and evaluated separately.

[0025] The first qualified transmitter element T1 can transmit the intensity T1:Low1, T1:Mid1, or T1:High. The second qualified transmitter element T2 can transmit the intensity T2:Low2, T2:Mid2, or T3:High. The third qualified transmitter element T3 can transmit the intensity T3:Low3, T3:Mid3, or T3:High. The intensities Tx:High, T1:High, T2:High, and T3:High are equal. All other intensities are lower. The sequence of intensities is ascending: T1:Low1 < T2:Low2 < T3:Low3 < Mid1 < Mid2 < Mid3 < Tx:High. The three qualified receiver elements R1, R2, and R3 can each apply the amplification Rx:Low or Rx:High.

[0026] The control device controls the unqualified transmitter and receiver elements in such a way that Rx:High is applied for distances above 1 m and Rx:Low is applied for distances below 1 m, the latter in order to avoid reflection.

[0027] The control unit controls a sequence of combinations of different intensities and gains and evaluates them to obtain a distance value. The highest intensity, Tx:High, is not used for this purpose. The combinations are each controlled and evaluated separately. The combinations are: T1:Low1+R1:Low, T1:Mid1+R1:Low, T1:Low1+R1:High, T1:Mid1+R1:High, T2:Low2+R2:Low, T2:Mid2+R2:Low, T2:Low2+R2:High, T2:Mid1+R2:High, T3:Low3+R3:Low, T3:Mid3+R3:Low, T3:Low3+R3:High, T3:Mid1+R2:High

[0028] These are 12 combinations.

[0029] Fig. 3is a diagram 40 for intensity versus distance and shows the measurement curve of a combination. The x-axis 41 shows the distance from the transmitter bar to the receiver bar. Point 42 shows the minimum distance, and point 43 shows the maximum evaluable distance. The y-axis 44 shows the intensity value output by a qualified receiver element for a specific combination.

[0030] Measurement curve 51 shows, as an example, a combination with medium intensity of the qualified transmitter element and medium gain of the qualified receiver element. Measurement curve 51 exhibits a very steep gradient at medium distances, saturates at shorter distances, and has no signal at longer distances. The measurement curve therefore only reproduces a small distance range with good resolution.

[0031] Fig. 4 is a diagram 40 according to Fig. 3and shows an overlay of all twelve measurement curves 52 for the twelve combinations.

[0032] The different intensities and the amplification Rx:Low are selected so that a largely uniform sequence of the steep courses of the measurement curves over the distance is achieved.

[0033] Fig. 5 shows a diagram for the sum of the intensity values ​​of all twelve combinations. The x-axis is analogous to the Fig. 3 The Y-axis shows the sum 71 of the intensity values ​​of all twelve combinations of Fig. 4 The sum shows a largely linear trend over the entire distance.

[0034] The control unit adds the measured and amplified intensity values ​​of the twelve combinations of a sequence and outputs a distance value based on the sum. The control unit repeats the sequence periodically and outputs the distance value periodically.

[0035] The light curtain according to the invention can be used to measure the opening movement of an elevator car door. Likewise, the distance from movable barriers of a passage monitored by a light curtain can be measured by the light curtain itself.

[0036] The light grid according to the invention can have a transmitter device that wirelessly transmits the distance value, particularly to a web cloud. This makes the data available for evaluation or stores it for extended periods to provide information about process sequences, like a black box. In particular, this allows an elevator door to be monitored independently of the elevator control system. List of reference symbols:

[0037] 10Cabin door 20Light grid 21Transmitter bar 22Receiver bar 30Light beams 31Qualified transmitter elements 32Qualified receiver elements 33Simple transmitter elements 34Simple receiver elements 35Control device 40Diagram of intensity versus distance 41X-axis: Distance between transmitter and receiver bar 42Minimum distance 43Maximum distance 44Y-axis: Received and amplified intensity 45No detection 46Saturation 51Measurement curve for one intensity and one gain 5212 measurement curves from 6 intensities and 2 gains 60Diagram of the sum of the 12 received measurement curves 64Y-axis: sum of the amplified intensities 71Sum of the 12 measurement curves of 6 intensities and 2 amplifications

Claims

1. Light grid (20) for determining the distance between transmitter strip and receiver strip, having a transmitter strip (21) with one or more transmitter elements that emit radiation with a specific intensity, having a receiver strip (22) with one or more receiver elements that receive the radiation from an associated transmitter element and having a control device (35) for driving the transmitter elements and / or the receiver elements and for evaluating the receiver elements, wherein in each case the transmitter element and the receiver element or in each case at least one of the transmitter elements or at least one of the receiver elements are designed as qualified transmitter and receiver elements, wherein the qualified transmitter element (31) or the qualified transmitter elements are designed to transmit different intensities and / or the qualified receiver element (32) or the qualified receiver elements are designed to apply different gains and output an intensity value for the received and amplified radiation, and the control device is designed to drive different combinations of intensities and gains of the qualified transmitter or receiver elements and ascertain a distance value on the basis of the sum of the resultant intensity values of the driven combinations, characterized in that the control device is designed to drive the combinations successively in a sequence and repeat the sequence periodically and ascertain the sum of the driven combinations of a sequence and ascertain a distance value for each sequence.

2. Light grid according to Claim 1, characterized in that the light grid, in particular the transmitter and receiver strips, furthermore comprises at least one or more further transmitter and receiver elements, which are each designed as non-qualified transmitter elements (33) and non-qualified receiver elements (34) and which are each designed as a light curtain and which preferably do not contribute to the combinations or from which the distance value is not ascertained, or which are used for object detection, or whose non-qualified transmitter elements emit at least one intensity like the qualified transmitter elements and whose receiver elements have at least one gain like the qualified receiver elements.

3. Light grid according to Claim 2, characterized in that all different combinations of intensities and gains of the qualified transmitter or receiver elements are driven, without however the highest intensity of the qualified transmitter elements being used for the combinations, or those intensities and gains of the qualified transmitter and receiver elements that correspond to the intensities and gains of non-qualified transmitter and / or receiver elements are used for object recognition.

4. Light grid according to either of Claims 2 and 3, characterized in that the one or more qualified transmitter elements are designed to each emit a plurality of different intensities on an individual basis or emit mutually different intensities or each emit an identical intensity, the latter in particular being the highest intensity and in particular corresponding to the intensity of the non-qualified transmitter elements.

5. Light grid according to any of Claims 2-4, characterized in that the one or more qualified receiver elements are designed to each apply a plurality of different gains on an individual basis or apply the same different gains or each apply an identical gain, the latter in particular being the highest and corresponding to the gain of the simple receiver elements.

6. Light grid according to any of Claims 2 to 5, characterized in that the light grid in each case comprises three qualified transmitter and receiver elements and furthermore comprises simple transmitter and receiver elements that do not contribute to the combinations and / or from which the distance value is not ascertained, the one or more qualified transmitter elements are designed to emit three intensities in each case, wherein one intensity is equal to the intensity of the simple transmitter elements that are provided for object recognition, and wherein two intensities are lower than the identical intensity and in each case differ from all other intensities, and the one or more qualified receiver elements are designed to apply the same two different gains in each case, wherein the higher gain corresponds to the gain of the simple receiver elements that are provided for object recognition, and the control device is designed to form twelve combinations from the three qualified transmitter and receiver elements, the two altogether different, lower intensities of the qualified transmitter elements and the two different, in each case identical gains of the receiver elements and use those intensities and gains of the qualified transmitter and receiver elements that correspond to the intensities and gains of simple transmitter and / or receiver elements for object recognition.

7. Light grid according to any of Claims 1 to 6, characterized in that the light grid comprises a transmission device that is designed to send the distance value wirelessly.