Elevator system having a laser distance-measuring device

Abstract

The invention relates to an elevator system having a laser distance-measuring device. Said elevator system has an elevator car, which can be moved in a shaft, and a position-determining unit for sensing a current position of the elevator car in the shaft. The position-determining unit has a laser which is fastened to the elevator car and which is designed to emit a laser beam, a laser distance-measuring device which is fastened to the elevator car and which is provided for sensing the distance of a point irradiated by the laser beam, a mirror which is fastened to the elevator car and which is designed to deflect the laser beam, and a fixed point which is located on the elevator car. The mirror can be adjusted between a position-measuring mirror configuration and a checking mirror configuration. In the position-measuring mirror configuration the mirror is configured to direct the laser beam at a first measurement point in the shaft, such that the sensed distance of the first measurement point is indicative of the current position of the elevator car in the shaft, and in the checking mirror configuration the mirror is configured to direct the laser beam at a fixed point.

Description

[0001] 2023P00389WÖ

[0002] - 1 -

[0003] Lifting system with a laser distance measuring device

[0004] The invention relates to an elevator system with a laser distance measuring device.

[0005] It is already known that in an elevator system, an elevator car is moved along a vertical travel path to transport passengers between different floors of a building. This is achieved using a drive motor controlled by an elevator control system. During operation, it is necessary to know the current position of the elevator car as precisely as possible so that the elevator control system can move the car to a desired position with appropriate control of the drive motor. For example, the elevator car might be moved to a specific floor of the building and positioned there so that its floor is flush with the floor of that floor.

[0006] Furthermore, it is known that the position and speed of the elevator car are monitored for the safe operation of the elevator system. Conventionally, an elevator system has several switches for this purpose, which detect the car's position at specific points and, if necessary, initiate measures to ensure safety. For example, a shaft limit switch can be installed at each end of the shaft, which opens a safety circuit of the elevator system as soon as the car reaches it. A mechanical speed limiter is conventionally used to monitor the speed. As an alternative to switches for determining the position, the car's position can also be determined using a position detection unit. As is known, the car's speed can also be calculated from its position, or from several position measurements. Thus, the position detection unit can determine the 2023P00389WÖ

[0007] - 2 -

[0008] The position monitoring unit can perform the function of a position monitor and / or speed limiter. For this purpose, the position detection unit can, for example, interrupt the safety circuit of the elevator system, control brake actuators, and / or electronically influence the elevator control system to ensure safety. Such position detection units and / or control systems are well known from the prior art; see, for example, WO 2016 / 062686 A1, EP 1 602 610 A1, EP 2 022 742 A1, EP 2 594 519 A1, or DE 10 2011 054 590 A1. The concepts described therein can also be combined.

[0009] It is already known to measure the current position of an elevator car using a laser distance measuring device and to transmit the current position of the elevator car to the elevator control system so that it can control the drive machine as necessary.

[0010] A lift system is known from WO 2020 / 126429 A1, which includes a lift car and a laser distance measuring device. The lift car of the lift system travels along a path that is bounded above by an upper limit and below by a lower limit. The laser distance measuring device is configured to emit a laser beam and determine the distance to the point where the laser beam intersects an object. The laser distance measuring device is mounted on the lift car and configured such that the laser beam can be directed upwards to the upper limit in one configuration and downwards to the lower limit in a second configuration. This allows the current position of the lift car to be determined redundantly.Furthermore, in a third configuration, lateral distances to boundary markers can be measured in order to provide and read out information encoded by the boundary markers. The boundary markers can be implemented, for example, using metal plates mounted on a side wall of the elevator shaft. The laser distance measuring device has a mirror located between 2023P00389WÖ.

[0011] - 3 - can be moved to a first mirror position, a second mirror position and a third mirror position to align the laser beam in the first, second or third configuration.

[0012] The object of the invention is to provide an elevator system in which the accuracy and / or reliability of determining the position of the elevator car is increased.

[0013] This problem is solved by an elevator system with the features specified in claim 1. This elevator system comprises an elevator car movable in a shaft and a position determination unit for detecting the current position of the elevator car in the shaft.The positioning unit comprises a laser designed to emit a laser beam, attached to the elevator car; a laser distance measuring device attached to the elevator car for measuring the distance to a point illuminated by the laser beam; a mirror attached to the elevator car designed to deflect the laser beam; and a fixed point arranged on the elevator car, wherein the mirror is adjustable between a position measuring mirror configuration and a verification mirror configuration, and wherein the mirror in the position measuring mirror configuration is configured to direct the laser beam to a first measuring point in the shaft such that the measured distance of the first measuring point is indicative of the current position of the elevator car in the shaft, and wherein the mirror in the verification mirror configuration is configured to direct the laser beam to the fixed point.

[0014] Such an elevator system increases the accuracy and / or reliability of detecting the current position of the elevator car in the shaft, since it allows the orientation of the emitted laser beam to be continuously readjusted and / or checked during operation by activating the verification mirror configuration. The frequency of activation of the verification mirror configuration is freely adjustable. 2023P00389WÖ

[0015] - 4 -

[0016] For example, the elevator system's operating program can be programmed such that the adjustable mirror is first automatically moved into the inspection mirror configuration, where a measurement process determines any deviations from a normal state. Subsequently, in position measurement mode, the elevator car's position is determined by adjusting the mirror to an initial position. Any deviations from the target state detected in the inspection mirror configuration are taken into account. In this procedure, the elevator car's position is determined, for example, by measuring its distance from an upper boundary in the elevator shaft. The accuracy of this position determination is optimized by prior measurement of the laser's distance from the fixed point in the inspection mirror configuration.Furthermore, or alternatively to improve the accuracy of the measurement, an error in the laser distance measuring device can be detected in the verification mirror configuration if the distance between the laser and the fixed point changes to an unacceptable degree.

[0017] According to one embodiment of the invention, in the inspection mirror configuration, the mirror and the fixed point are at a fixed distance from the laser, with both the mirror and the laser being rigidly connected to the elevator car. Preferably, the laser and the mirror are rigidly connected to the top of the elevator car.

[0018] According to one embodiment, in the inspection mirror configuration, a measured value for the determined distance is evaluated by the laser distance measuring device.

[0019] According to one embodiment, the adjustable mirror in the position-measuring mirror configuration can be directed upwards in a first mirror position up to an upper limit in order to determine the distance of the elevator car from the upper limit. 2023P00389WÖ

[0020] - 5 -

[0021] According to one embodiment, the adjustable mirror can be directed downwards in a second mirror position up to a lower limit in order to determine the distance of the elevator car from the lower limit.

[0022] According to one embodiment, the adjustable mirror can be directed towards a lateral boundary in a fourth mirror position, whereby this lateral boundary is not fixedly connected to the elevator car.

[0023] According to one embodiment, the lateral boundary is a side wall of the elevator system provided outside the elevator car, wherein in the fourth mirror position a measurement of the distance of the elevator car from the side wall of the elevator system can be carried out.

[0024] According to one embodiment, the laser distance measuring device is designed to detect errors by summing or subtracting the values.

[0025] According to one embodiment, if an incorrect alignment of the emitted laser beam is detected, the alignment of the emitted laser beam is corrected, preferably automatically.

[0026] The aforementioned embodiments can be used individually or – provided they are not mutually exclusive – also together.

[0027] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. It shows

[0028] Figure 1 shows a block diagram of an elevator system which includes a laser distance measuring device.

[0029] Figure 2 is a block diagram showing the laser and the mirror in a first mirror position of the position measuring mirror configuration, 2023P00389WÖ

[0030] - 6 -

[0031] Figure 3 shows a block diagram in which the laser and the mirror are shown in a second mirror position of the position measuring mirror configuration.

[0032] Figure 4a shows a first block diagram in which the laser and the mirror are shown in a verification mirror configuration,

[0033] Figure 4b shows a second block diagram in which the laser and the mirror are shown in a verification mirror configuration, and

[0034] Figure 5 is a block diagram showing the laser and the mirror in a third mirror position.

[0035] Figure 1 shows an elevator system 1 which has a laser distance measuring device 8.

[0036] This elevator system 1 comprises a movable elevator car 2 arranged in an elevator shaft 7 and a position determination unit for recording the current position of the elevator car 2 in the elevator shaft 7. The elevator car 2 is controlled by an elevator control unit 3 via a drive motor 4.

[0037] The elevator car 2 is movable between an upper limit 11 and a lower limit 13, both located in the elevator shaft 7. This movement of the elevator car 2 is effected by the drive motor 4 via belt-shaped support elements, which are not shown in detail in Figure 1. The upper limit 11 and the lower limit 13 are arranged vertically above one another and are used to determine the current position of the elevator car 2. Alternatively, other support elements such as ropes, in particular wire ropes, or other drive concepts such as hydraulic drives or linear motors can be used. 2023P00389WÖ

[0038] - 7 -

[0039] A laser 6 is attached to the elevator car 2 and is designed to emit a laser beam 5. The laser 6 is connected to the laser distance measuring device 8, which is designed to detect the current position of the elevator car 2 in the elevator shaft 7. For this purpose, the laser distance measuring device 8 determines the distance from the laser to a point illuminated by the laser.

[0040] The laser 6 and the laser distance measuring device 8 are typically arranged in a common housing; the following description assumes this configuration. The components for evaluating the measurement performed by the laser distance measuring device 8, in particular a processor, memory, and other electrical components necessary for evaluating the measurement, can also be arranged in a separate housing, which does not necessarily have to be mounted on the elevator car. The sensor of the laser distance measuring device 8 could also be mounted independently of the laser 8 on the elevator car 2.

[0041] The laser beam 5 emitted by the laser 6 strikes an adjustable mirror 9, which is also attached to the elevator car 2. This mirror 9 is movable and adjustable between at least one position-measuring mirror configuration and a verification mirror configuration, as will be explained in more detail below with reference to Figures 2-5. Preferably, the adjustable mirror can assume at least two position-measuring mirror configurations.

[0042] By means of this mirror 9, a laser beam 5 emitted by the laser 6 can be deflected, so that in a first mirror position the laser beam is deflected vertically upwards by the mirror 9, strikes the upper boundary 11 at a first measuring point, is reflected vertically downwards from there, is deflected again by the mirror 9 and then returns to the laser 6 or the laser distance measuring device 8. 2023P00389WÖ

[0043] - 8 -

[0044] Furthermore, by means of this mirror 9, a deflection of the laser beam 5 emitted by the laser 6 can be carried out in such a way that in a second mirror position the laser beam is deflected vertically downwards at the mirror 9, hits the lower boundary 13 at a second measuring point, is reflected vertically upwards again from there, is deflected again at the mirror 9 and then reaches the laser 6 or the laser distance measuring device 8 again.

[0045] Position signals are determined in the laser distance measuring device 8 from the travel times of the laser beam reflected back to the laser 6. These position signals are indicative of the current position of the elevator car 2 in the elevator shaft 7. These position signals are transmitted to the elevator control unit 3. The elevator control unit generates, for example, control signals for the drive control unit 4 from the position signals, which in turn drives the elevator car 2 as required.

[0046] Furthermore, the position signals can be used to monitor the safety of the elevator system, and the elevator system can be brought into a safe state if necessary, for example by opening a safety circuit not shown in the figures. This can be triggered, for example, by the laser distance measuring device 8 itself or by a safety module provided in the elevator control unit 3. Other possibilities are known to those skilled in the art.

[0047] Mirror 9 is also adjustable to a third mirror position. This third mirror position is a verification mirror configuration in which the laser 6, and thus the emitted laser beam, is checked. In this verification mirror configuration, the laser beam is directed onto a fixed point. The fixed point is located at a fixed or constant distance from the laser. 2023P00389WÖ

[0048] - 9 -

[0049] In the illustrated embodiment, the laser beam is directed to the fixed point when the emitted laser beam is shone directly onto the mirror 9 without any angular adjustment of the mirror 9, is reflected back from the mirror 9, and is then reflected directly onto the laser 6. Since, in this inspection mirror configuration, both the laser 6 and the mirror 9 are fixedly mounted on or to the elevator car 2, the emitted laser beam is not deflected by the mirror 9, but rather emitted directly to a fixed point and reflected directly from there to the laser 6. This allows for a measurement of the laser beam's transit time over a known, predetermined distance.This allows the emitted laser beam to be checked in such a way that the accuracy and / or reliability of subsequent measurements of the transit times in the position measuring mirror configurations, in which the emitted laser beam 5 is deflected by means of the mirror 9, is increased and / or ensured. The fixed point is therefore formed by the mirror itself.

[0050] The verification process can include calibration, for example, to correct measurement fluctuations caused by temperature variations. Other fluctuations in environmental conditions, such as humidity, can also lead to measurement variations.

[0051] Alternatively, the inspection can include detecting a malfunction of the positioning unit. Since the laser and the fixed point are attached to the elevator car—and thus also located within the elevator car—their relative positions do not change in the inspection mirror configuration. Therefore, any change in distance measurement should only occur within a range that can be explained by fluctuations inherent in the measuring principle. If the distance measurement falls outside this range and has thus changed to an impermissible extent, a fault in the laser and / or the laser distance measuring device can be inferred. 2023P00389WÖ

[0052] - 10 -

[0053] In the event of a fault, the position measurement performed by the positioning unit is no longer reliable and therefore must no longer be used for the safe operation of the elevator system. Typically, safety in the event of a fault is ensured by the elevator system being shut down by the control system.

[0054] Alternatively, the inspection mirror configuration can also be implemented by deflecting the emitted laser beam at mirror 9 so that it is directed towards a fixed point located at a predetermined fixed location within the elevator car. From there, it is reflected back to the mirror and then sent back to the laser 6 or the laser distance measuring device 8. In this case as well, the travel time of the laser beam over a known, predetermined distance is measured, since both the laser and the predetermined fixed location within the elevator car are at a predetermined distance from each other.

[0055] Alternatively, the inspection mirror configuration can also be implemented by swiveling mirror 9 out of the laser beam so that the laser beam hits the fixed point directly. The fixed point, in turn, has a fixed distance to laser 6, regardless of the position of elevator car 2 in shaft 7.

[0056] Furthermore, the mirror 9 can also be directed into one or more additional mirror positions. For example, in a fourth mirror position, the mirror 9 can be directed towards a lateral boundary, whereby this lateral boundary is not rigidly connected to the elevator car 2, but is, for example, a side wall 15 of the elevator system 1 located outside the elevator car 2, on which markings are attached at different heights, for example, marking plates. In this fourth mirror position, a measurement of the distance of the elevator car 2 from the side wall 15 of the elevator system 1 can be carried out. This makes it possible to determine the distance of the elevator car 2 from the side wall of the elevator system 1 during operation of the elevator system.

[0057] - 11 - monitor and take appropriate countermeasures in the event of an emergency. Such an emergency occurs, for example, when the distance between the side wall 15 of the elevator system 1 and the side wall of the elevator car 2 becomes increasingly smaller, so that a side wall of the elevator car 2 first rubs against the side wall 15 of the elevator system 1 and then an unintended blockage of the transport of the elevator car 2 occurs.

[0058] Figure 2 shows a block diagram in which the laser 6 and the mirror 9 are shown in a first mirror position 10 of the position-measuring mirror configuration. This block diagram shows that the laser beam emitted by the laser is emitted to the mirror 9, is deflected vertically upwards by the mirror 9 in the first mirror position 10, is reflected from the upper boundary 11, is deflected again by the mirror 9 in the first mirror position 10, and returns to the laser 6 or the laser distance measuring device 8.

[0059] Figure 3 shows a block diagram in which the laser 6 and the mirror 9 are shown in a second mirror position 12 of the position measuring mirror configuration. This block diagram shows that the laser beam emitted by the laser is emitted to the mirror 9, is deflected vertically downwards by the mirror 9 in its second mirror position 12, is reflected from the lower boundary 13, is deflected again by the mirror 9 in its second mirror position 12, and returns to the laser 6 or laser distance measuring device 8.

[0060] Figure 4a shows a first block diagram in which the laser 6 and the mirror 9 are shown in the inspection mirror configuration in a third (inspection) mirror position 18. From this block diagram, it can be seen that the laser beam emitted by the laser 6 is emitted to the mirror 9, is deflected at the mirror 9, which is in the third mirror position 18, such that it strikes a fixed point located on the elevator car 2, and from there to the mirror 9, which is in mirror position 18. 2023P00389WÖ

[0061] - 12 - is reflected and then returns to the laser 6 or laser distance measuring device 8. Since the fixed point, the mirror 9 and the laser are each rigidly connected to the elevator car 2, the fixed point has a defined distance to the laser.

[0062] Figure 4b shows a second block diagram in which the laser 6 and the mirror 9 are arranged in a verification mirror configuration. This block diagram illustrates that the laser beam emitted by the laser 6 strikes the mirror, is not deflected by it, but reflected, and the reflected laser beam is sent back to the laser 6 or the laser distance measuring device 8. In this case, the fixed point is the mirror itself. Since the mirror and the laser are each rigidly connected to the elevator car 2, the fixed point has a defined distance to the laser.

[0063] Figure 5 shows a block diagram in which the laser 6 and the mirror are shown in a fourth (shaft wall) mirror position 17, or shaft wall mirror configuration. This block diagram shows that the laser beam emitted by the laser 6 is not deflected by the mirror in position 17 and then strikes a measuring point located outside the elevator car 2 on a shaft side wall 15 of the elevator shaft 7. This shaft side wall forms a lateral boundary 16 of the elevator shaft 7. From this measuring point, the emitted laser beam is reflected back to the laser 6, as can be seen in Figure 5. In this way, a distance between the side wall 15 of the elevator shaft and the elevator car 2 can be determined, as is known, for example, from WO 2020 / 126429 A1.

[0064] This measurement of the lateral distance can alternatively or additionally enable the provision and reading of information encoded by boundary markers attached to the shaft side wall 15. The boundary markers can be, for example, constructed using structures (e.g., metal sheets) 2023P00389WÖ

[0065] - 13 - are implemented, which are mounted on the shaft side wall 15 of the elevator shaft.

[0066] Aspects of the invention described above, in particular the calibration mirror configuration, offer a multitude of advantages.

[0067] The invention described above has a multitude of advantages.

[0068] Many known elevator systems use several additional sensors to determine the current position of the elevator car, such as accelerometers, car door sensors, and door proximity sensors. This additional use of sensors is necessary to meet existing safety requirements. This entails considerable effort regarding the elevator design and aspects of reliable fault detection and prevention. In contrast, the present invention provides a solution that uses only a single laser designed to measure the operating states of the elevator system by enabling measurements in different directions to redundantly address required safety aspects. The advantages of the invention are particularly enhanced by the use of an adjustable mirror.This mirror alters the angle of a laser beam emitted by a laser such that signals reflected by a reflector located at the bottom of the elevator shaft, signals reflected by a reflector located at the top of the elevator shaft, and / or signals reflected at other locations within the elevator shaft can be measured and evaluated. To increase the accuracy and / or reliability of all measurements, a verification mirror configuration is adjustable according to the invention, in which the emitted laser beam is directed onto a fixed point.

[0069] The mirror can be adjusted, for example, using stepper motors. 2023P00389WÖ

[0070] - 14 -

[0071] Among other things, the following checks can be carried out using the features specified in the patent claims to ensure that the position determination unit of the elevator system delivers accurate and reliable results:

[0072] It can be verified whether, after completion of a learning phase in the operation of the elevator system, the sum of the measured distance of the elevator car from the lower limit and the measured distance of the elevator car from the upper limit of the travel path always yields identical results.

[0073] It can be verified whether the measurement, which is carried out as part of the verification mirror configuration, always delivers consistent results.

[0074] It can be checked whether the measurement results indicate a blockage of the elevator car.

[0075] It can be checked whether the laser is currently working correctly or not. For example, it will not work correctly if no position signals are provided.

[0076] These criteria can be used to check whether the laser operates reliably within specified tolerances. If this is not the case, an error signal can be output.

[0077] The present invention reduces, among other things, the complexity of the required safety devices for an elevator system, since, for example, a second laser for redundant position measurement can be dispensed with. 2023P00389WÖ

[0078] - 15 -

[0079] In an elevator system with the features according to the invention, the beam alignment can be self-adjusted to the reflectors used. Thanks to the reduced complexity of an elevator system according to the invention, development and testing efforts are reduced. Furthermore, material costs are reduced.

[0080] Advantages of the invention also include the fact that the reliability of an elevator system with the features of the patent claims is improved, since fewer sensors are needed, the failure of which would lead to malfunctions of the elevator system.

[0081] 2023P00389WÖ

[0082] - 16 -

[0083] List of reference signs

[0084] 1 elevator system

[0085] 2 elevator cabins

[0086] 3 Elevator control

[0087] 4 drive machine

[0088] 5 Laser beam

[0089] 6 lasers

[0090] 7 Shaft

[0091] 8 Laser distance measuring device

[0092] 9 mirrors

[0093] 10 first mirror position

[0094] 11 upper limit

[0095] 12 second mirror position

[0096] 13 lower limit

[0097] 14 third mirror position

[0098] 15 Side wall of the elevator system

[0099] 16 lateral boundary

[0100] 17 fourth mirror position

[0101] 18 third mirror position

Claims

2023P00389WÖ - 17 - Patent claims 1. Elevator system (1) comprising an elevator car (2) movable in a shaft (7) and a position determination unit for detecting the current position of the elevator car (2) in the shaft (7), wherein the position determination unit comprises: a laser (6) attached to the elevator car (2) and designed to emit a laser beam (5); a laser distance measuring device (8) attached to the elevator car for detecting the distance to a point illuminated by the laser beam; and a deflection device attached to the elevator car (2) for deflecting the laser beam. (5) formed mirror (9); a fixed point arranged on the elevator car (2), wherein the mirror is adjustable by the laser distance measuring device (8) such that it is adjustable between a position measuring mirror configuration and a verification mirror configuration, wherein the mirror in the position measuring mirror configuration is configured to direct the laser beam to a first measuring point in the shaft such that the detected distance of the first measuring point is indicative of the current position of the elevator car (2) in the shaft (7), and the mirror in the verification mirror configuration is configured to direct the laser beam to the fixed point.

2. Elevator system according to claim 1, in which the mirror and the fixed point in the inspection mirror configuration have a fixed predetermined distance from the laser (6).

3. Elevator system according to claim 1 or 2, in which a measured value for the determined distance is evaluated by the laser distance measuring device in the inspection mirror configuration.

4. Lifting system according to one of the preceding claims, in which the adjustable mirror (9) in the position measuring mirror configuration can be directed upwards in a first mirror position (10) up to an upper limit (11). 2023P00389WÖ - 18 - 5. Lifting system according to one of the preceding claims, in which the adjustable mirror (9) in the position measuring mirror configuration can be directed downwards to a lower limit (13) in a second mirror position (12).

6. Elevator system according to one of the preceding claims, in which the adjustable mirror (9) in the inspection mirror configuration can be directed into a third mirror position.

7. Elevator system according to claim 6, in which the adjustable mirror (9) can be directed towards a lateral boundary (16) in a fourth mirror position (17).

8. Elevator system according to claim 7, wherein the lateral boundary (16) is a side wall (15) of the elevator system (1) provided outside the elevator car (2).

9. Elevator system according to claim 8, in which in the fourth mirror position (17) a measurement of the distance of the elevator car (2) from the side wall (15) of the elevator system (1) can be carried out.

10. Elevator system according to one of claims 3 - 9, in which the laser distance measuring device (8) is designed to detect errors by summing or subtracting.

11. Elevator system according to claim 10, in which, upon detection of an incorrect alignment of the emitted laser beam (5), the alignment of the emitted laser beam is corrected.

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