DE102023112419A1 - Inspection of elevator systems based on distance measurements - Google Patents

Abstract

A method for checking an elevator system with a rotatably mounted traction sheave comprises at least the following steps: operating the elevator system (10) according to a predefined operating sequence, wherein at least one movable element (12, 14, 16) of the elevator system (10) is moved by driving the traction sheave (18); detecting a plurality of distance values (32) while the movable element (12, 14, 16) is moved, wherein the distance values each represent a distance (30) between the movable element (12, 14, 16) and a stationary element (31, 33, 29) of the elevator system (10); and determining at least one test parameter (40) on the basis of the plurality of distance values (32), wherein the test parameter represents the driving ability of the traction sheave (18).

Description

The present invention relates to a method for checking elevator systems, in particular rope elevator systems.

Operators of elevator systems are obliged to regularly check operational safety. In particular, it must be checked regularly whether the elevator system meets the specification for which the elevator system is approved. In the case of a rope elevator, for example, it must be ensured that the elevator system can reliably move and hold the maximum transport weight in the elevator car without the support element slipping on the traction sheave, which is critical to safety. For this purpose, the so-called traction capacity is determined, which must be checked regularly in accordance with the relevant regulations, in particular the technical rules for operational safety (TRBS 1201-4).

The traction capability generally represents the slip resistance of one or more support elements (e.g. support ropes or straps) on the traction sheave. It can be determined using known methods by first loading the car with a nominal load plus an additional load for a safety margin. The loaded car is then moved by the traction sheave in various operating situations, preferably in a downward direction, and strongly decelerated in order to determine whether or not the support element slips.

In practice, the described test procedure is very complex to carry out, as defined test loads have to be loaded into the elevator and then removed again after the test has been completed and, if necessary, taken to the next test location. The test also requires several people who need special training, which increases the effort required for the test accordingly.

Against the background described, the object of the present invention is to provide a method of the type mentioned at the outset and a testing device for a rope elevator system, which allows a simpler and more reliable testing of the driving ability of elevator systems.

The object is achieved according to a first aspect by a method having the features of claim 1. The method comprises at least the following steps: operating the elevator system according to a predefined operating sequence, wherein at least one movable element of the elevator system is moved by driving the traction sheave; detecting a plurality of distance values while the movable element is being moved, wherein the distance values each represent a distance between the movable element and a stationary element of the elevator system; and determining at least one test parameter on the basis of the plurality of distance values, wherein the test parameter represents the driving ability of the traction sheave.

The method is based on measuring distance values between a moving element and a stationary element of the elevator system. Distance values offer the advantage over other measured variables that they can be recorded with high accuracy and speed and that several compact and reliable sensor types are available for this purpose. The distance values can also be used to determine other measured variables such as the speed or acceleration of the moving element, which in turn can be used to determine the traction capability.

The moving element can be, for example, the elevator car, a counterweight or another element that performs at least a qualitatively similar movement during operation. On the basis of the distance values, a simple yet reliable determination and verification of the driving ability is possible.

Embodiments of the invention are disclosed in the dependent claims, the description and the figures.

According to one embodiment, the method includes determining whether the test parameter violates a predetermined test criterion. This step can be carried out by a person trained to check elevator systems, who evaluates the test parameter based on prior knowledge. However, the step, like determining the test parameter, is preferably carried out as a computer-implemented method step. For example, it can be determined with the aid of a computer whether the test parameter exceeds or falls below one or more safety-relevant threshold values, which can be formed by reference values of the traction capability.

According to one embodiment, the elevator system is formed by a cable elevator system. In this case, the movable element is usually formed by a first load element (eg the elevator car) which is connected to a second load element of the elevator system (eg a counterweight) via at least one support means. The support means is diverted and driven between the first load element and the second load element by means of a rotatably mounted traction sheave in order to move the first load element and the second load element simultaneously. In operation, the support means is diverted and driven between the first load element and the second load element by means of a rotatably mounted traction sheave in order to move the first load element and the second load element simultaneously. The support means wraps around the traction sheave along its circumference with a contact surface that is decisive for the static friction between the support means and the traction sheave. The resulting static friction therefore defines the driving ability of the traction sheave.

A support means can generally be formed by a rope or a belt. Other types of rope-like connecting elements are also conceivable.

According to a further embodiment, a mass is determined for at least one section of the suspension element, which is used to determine the test parameter. For example, the proportional cable mass that is added to the effective total weight on one cable side of the traction sheave, e.g. the elevator car side, can be included in the determination of the test parameter. Taking the proportional suspension element mass into account makes it possible to determine the traction capability with greater accuracy.

According to a further embodiment, the movable element is formed on a speed limiter or a shaft copy of the elevator system. These elements are generally easily accessible so that, for example, a mobile test or sensor device for carrying out the method can be selectively mounted there.

According to a further embodiment, the distance values are recorded with at least one sensor device, in particular a mobile sensor device. The sensor device can be arranged on the movable element or on the stationary element of the elevator system. Two-part sensor devices are also possible, whereby, for example, an optoelectronic transmitter can be arranged on the movable element and an optoelectronic receiver on the stationary element. The transmitter and receiver are communicatively connected to one another in order to determine the distance values from a pulse transit time between the transmitter and receiver. In the case of a mobile sensor device, this is preferably designed as one piece with a housing. It can optionally be arranged flexibly on the elevator system in order to record the distance values and, if necessary, other measured values that are used to determine the traction capability.

To increase the test accuracy, the distance values can be recorded by several sensor devices arranged on the elevator system. These can be of the same type or different, e.g. based on different sensor types. The distance values can then be advantageously adjusted for measurement errors that can occur, for example, in the form of outliers. For example, the distance values can be measured redundantly by different sensor types and the measurement inaccuracies of the individual sensor types can be compensated.

It has proven particularly advantageous to determine the distance of the movable element using both a sensor of a mobile sensor device and an internal distance sensor of the support means. Alternatively, it is possible to determine the distances and/or acceleration values of the movable element using several distance sensors integrated in the sensor device.

According to a further embodiment, the distance values are detected using at least one sensor device that has a transmitter for transmitting a transmission signal and a receiver for receiving a reception signal. In this case, the detection of the distance values comprises at least the following steps: operating the transmitter for transmitting a transmission signal between the movable element and the stationary element; operating the receiver for receiving a reception signal; and comparing the transmission signal and the reception signal.

The transmission signal preferably has a laser beam, which enables precise and reliable distance measurement under variable environmental conditions. The sensor device can thus generally be based on a laser and in particular have a LIDAR module (Light Detection And Ranging). Alternatively or additionally, the sensor device can determine distance values based on acoustic transmission signals, the frequency of which is preferably in the ultrasound range. However, other frequency ranges are conceivable.

According to a further embodiment, the distance values are recorded with a sensor device that has an optical image sensor. The image sensor is aligned on the elevator system in such a way that the image data generated by the sensor depict the respective distance between the movable and the stationary element. In this case, it is preferably not important in which Operating situation of the elevator system, i.e. the image data is suitable for distance measurement regardless of the position of the elevator car.

The image data serves as the basis for determining the distance values. For this purpose, automatic image data processing methods are preferably used, which can be based on deterministic evaluation rules and/or statistical models, in particular machine learning. The image data can be pre-processed to increase the evaluation accuracy by first detecting the image area of the moving and/or stationary element and then determining the distance value solely based on the detected image areas. Preferably, an image sensor is used in combination with a laser-based sensor in order to determine the distance values with even greater accuracy.

The test procedure described can be extended by determining additional measured values for a measured quantity that differs from the distance between the movable element and the stationary element. The additional measured values can be included in the determination of the test parameter in order to further increase its accuracy.

As an example of another measurement variable, an acoustic signal can be recorded on the elevator system while the moving element is being moved. For example, the vibrations caused by the support element (e.g. rope vibrations) can be measured, which can have a connection with the driving ability of the traction sheave. The test parameter can therefore advantageously be determined depending on the acoustic signal.

According to a further embodiment, the distance values and/or other measured values that are related to the driving ability are recorded using at least one mobile test device. The test device can be designed as a compact terminal device, so that it can be carried by a person responsible for the test like a smartphone or comparable terminal device and can be easily arranged on the elevator system to be tested. The test can be carried out particularly flexibly in this way. A further advantage is that the mobile test device can be moved while the distance values and/or other measured values are being recorded, for example if it is arranged on the elevator car or another moving part. However, it is also conceivable to arrange the test device in a fixed location, for example on a shaft floor of the elevator system. The test device can have one of the above-mentioned sensor devices for recording the distance values.

In a further embodiment, the measured values for determining the test parameter are evaluated depending on reference measured values. These can be based, for example, on a learning operation of the elevator system. Additionally or alternatively, reference measured values based on predetermined specification data of the elevator system can be included in the determination of the test parameter. The specification data include, for example, data provided by a manufacturer of the elevator system or a component of the elevator system (e.g. by a sensor manufacturer). The data contains information about an expected and operationally safe behavior of the underlying component. A comparison of the current measured data with the expected reference data can therefore indicate safety risks and be used for a reliable inspection of the elevator system.

The measured values can be compared with the reference values in various ways. Preferably, a predetermined mathematical relationship is formed between the current measured values and the reference values, for example a correlation function (e.g. in the form of a cross-correlation or convolution function). Additionally or alternatively, a statistical machine learning model can be used, which also forms mathematical relationships between the measured values, e.g. by applying kernel functions. However, simpler function types can also be used, e.g. a large number of threshold comparisons in a neural network or a regression model.

The distance values are recorded while the elevator system is being operated according to a predefined operating sequence. On the one hand, this operating sequence can be specified by a regular operating sequence programmed into the elevator system, for example an elevator ride between two levels. Additionally or alternatively, a safety operating sequence can be provided, in particular an emergency stop, in which the preferably empty elevator car is braked with maximum braking acceleration in the upward direction (travel towards the elevator shaft ceiling).

According to a further embodiment, the distance values are processed depending on predetermined tolerance ranges. For example, a subset of the distance values can be excluded from the determination of the test parameter or modified according to a predetermined filter function if the distance values of the subset have an associated tolerance range violate, ie exceed or fall below the corresponding threshold values. For example, distance values that exceed the height of the elevator shaft can be excluded from further processing due to a lack of plausibility. The reliability of the method can be significantly increased in this way; on the one hand because outliers in the measured values cannot influence the test result; on the other hand because the test model does not have to be designed to compensate for outliers. Measured values contaminated with noise or other measurement uncertainties can therefore also be used to check the elevator system.

According to a further embodiment, the method can be carried out at least partially on a central server which receives the measured values via a data network and determines the test parameter.

In a further embodiment, the method is at least partially embodied by a computer program in the form of instructions which, when the program is executed by a computer, cause the computer to carry out the method according to one of the described embodiments. In particular, the test parameter can be determined by a computer program.

The computer program is preferably stored as application software, in particular as an app on a mobile testing device or sensor unit that can be used to implement the method. For this purpose, the testing device can be equipped with a non-volatile memory and a processor unit for interpreting and executing the commands stored in the memory.

A further aspect of the invention relates to a mobile testing device for testing an elevator system, which can be designed in particular as a cable elevator system with a rotatably mounted traction sheave. The testing device is designed in accordance with the method aspects described above to record several distance values, each of which represents a distance between the movable element and the stationary element of the elevator system. The distance values can be recorded via sensors permanently mounted on the elevator system and/or via a sensor unit arranged on the testing device.

The test device preferably also comprises an evaluation unit for determining the test parameter on the basis of the distance values recorded by the sensor unit or the other sensors. One or more of the method aspects described above can be implemented here.

• 1 eine schematische Ansicht von Teilen einer Aufzugsanlage;
• 2 ein schematisches Blockschaltbild von Aspekten eines Verfahrens zur Überprüfung einer Aufzugsanlage; und
• 3 ein schematisches Blockschaltbild von weiteren Aspekten des Verfahrens zur Überprüfung einer Aufzugsanlage.

The described aspects of the invention are described below, purely by way of example, with reference to the drawings, in which:

• 1 a schematic view of parts of an elevator system;
• 2 a schematic block diagram of aspects of a method for checking an elevator installation; and
• 3 a schematic block diagram of further aspects of the procedure for checking an elevator system.

1 shows schematically components of a cable lift system 10 comprising a car 12 designed as a passenger cabin, which is connected to a counterweight 14 via one or more support means 16. The support means 16 can be designed as a rope or belt, for example, and is guided over a rotatably mounted traction sheave 18 and a deflection roller 20 that is also rotatably mounted. By driving the traction sheave 18 by means of an electric motor (not shown), the car 12 can be moved either vertically up or down in order to transport people or other payloads in the car 12 within the indicated elevator shaft 31 between predefined stopping positions, as is generally known in elevator systems.

Depending on the design of the elevator system 10, it is conceivable to dispense with the deflection pulley 20. Furthermore, it is conceivable that the drive of the elevator system 10 with the traction sheave 18 and any deflection devices is not as in 1 shown above the elevator shaft 31, but can be arranged at any height of the elevator shaft 31 (e.g. in the area of any floor).

Aspects of a method for checking the traction capability of the traction sheave 18 are described below.

First, the traction sheave 18 is driven to move the car 12 up or down in the vertical direction within the elevator shaft 31. To determine the distance values relevant for the test, the car 12 is moved in the upward direction (towards the ceiling of the elevator shaft 31) and decelerated to a standstill by activating the emergency stop.

During the upward movement of the car 12 and the activation of the emergency stop, a large number of distance values are measured. Distance values represent the spatial distance 30 between the elevator car 12 and a ceiling section 33 of the elevator shaft 31 (see dashed line in 1 ).

The distance values are measured at regular time intervals, with the distance values gradually reducing more slowly due to the deceleration of the elevator car 12 until it comes to a standstill. Alternatively or additionally, further distance values can be recorded which represent a spatial distance 27 between the counterweight 14 and a floor section 29 of the elevator shaft 31. The relevant distance values will also gradually reduce more slowly when the elevator car 12 moves upwards, i.e. in the direction away from the floor section 29, during the emergency stop.

To measure the first distance values (distance 30), a first mobile test device 24 is used, which is arranged on the roof of the elevator car 12 and has several sensors (not shown). On the one hand, a distance sensor is provided which emits a laser beam to the ceiling section 33 and determines the distance 30 by measuring the travel time until the reflected laser beam is received. On the other hand, the first test device 24 is equipped with a microphone which measures the acoustic emissions of the elevator system 10. In this way, acoustic vibrations can be measured which arise on the support element section 22 and provide conclusions about the driving ability of the traction sheave 18.

In addition, a second mobile testing device 28 is provided, which is arranged on the counterweight 14 and records the second distance values for measuring the distance 27. The second testing device 28 is connected via a wireless communication link to the first testing device 24, in which all measured values are brought together.

The distance values are stored and evaluated in an evaluation unit of the first test device 24, taking into account the associated time intervals between the individual measurements. In particular, the respective acceleration of the elevator car 12 and the counterweight 14 is determined from the distance values.

The distance values are also used to determine the length of the support element section 22, which extends between the traction sheave 18 and the elevator car 12, as well as the length of the support element section extending between the deflection pulley 20 and the counterweight 14 (see reference number 16). For this purpose, the fixed geometric conditions of the elevator system 10 are used, in particular the distance between the ceiling section 33 and the floor section 29 (height of the elevator shaft 31) as well as the distances of the traction sheave 18 and the deflection pulley 20 to the ceiling section 33.

In addition to the above-mentioned measured values, which are recorded directly by sensors of the test devices 24 and 28 or derived from the measured distance values, further measured values are recorded. These are measured by means of sensors permanently installed on the elevator system 10 and transmitted by a control device of the elevator system 10 to the first test device 24 via a wireless communication interface (in 1 not shown). This includes the current mass of the car 12 as well as other constant technical properties of the elevator system 10, in particular the mass of the counterweight 14, the total length and the mass of the support means 16.

The measured values are processed in the test device 24 in order to obtain a reliable estimate of the driving ability of the traction sheave 18. A corresponding method is described below with reference to 2 described in more detail. On the one hand, measured values 32 are used which are recorded directly by the test devices 24 and/or 28. These include in particular the distance values for the distances 30 and/or 27. On the other hand, measured values 34 are used which are read out by the elevator system 10 as described above and transmitted to the first test device 24.

The measurement value groups 32 and 34 are first subjected to preprocessing 36 in which the measurement values are compared with predefined threshold values. A portion of the measurement values that violate one or more threshold values are excluded from further processing. The measurement values are cleaned in this way. Furthermore, the measurement values 32, 34 are standardized.

In the following step 38, the measured values 32, 34 are processed with a machine-learned model that outputs the test parameter 40. The model was previously determined on the basis of a large number of training data, by specifying reference measured values that represent a desired operating behavior. Alternatively or additionally, the model can have a fixed calculation rule for the driving ability, which can be specified as follows: $$\frac{F1}{F2}=\frac{\text{G}\left(\text{G}+\ddot{\text{x}}\right)}{\text{F}\left(\text{G}-\ddot{\text{x}}\right)}$$

Here, x denotes the time-dependent distance travelled during the predetermined operating period run of the elevator car 12 or the support means 16 and the counterweight 14. Accordingly, ẍ denotes twice the time derivative of the distance, which corresponds to the acceleration of the elevator car 12 or the counterweight 14. The variable G denotes the mass of the counterweight 14, the variable F the mass of the elevator car 12 and g the acceleration due to gravity. It is possible to determine separate distances and separate acceleration values for the elevator car 12 and the counterweight 14 from the distance values recorded by the test devices 24 and 28. Separate acceleration values can therefore be used for the elevator car 12 and the counterweight 14. These can therefore also differ in terms of their magnitude. The distances are each determined as a difference between two successive distance values.

The test parameter is calculated depending on the described sizes as a ratio between F1 and F2, where F1 is the load-bearing element force on the side of the counterweight 14 and F2 is the load-bearing element force on the side of the car 12. Optionally, the proportional load-bearing element masses, which vary depending on the respective route position, can be added to the respective mass of the car 12 or the counterweight 14. This leads to greater accuracy because, for example, the measured mass of the car 12 also includes the mass of the load-bearing element section 22. The proportional load-bearing element masses can be determined by multiplying the proportional load-bearing element lengths by the previously known load-bearing element mass per unit length.

With reference to 3 Further aspects of the procedure of 2 described, which can be optionally implemented. In step 56, current measured values are recorded. These can generally be measured values that are recorded by means of a sensor unit or test device 54 arranged on the car 12 during operation of the elevator system 10. In particular, the values associated with 2 The measured values 32 and 34 described above were used.

In step 58, reference measurement values are recorded that were determined as part of a learning operation of the elevator system 10. In step 60, manufacturer measurement values are used that were determined in advance independently of the specific elevator system 10. The data used in steps 58 and 60 are preferably stored on a central server ("cloud") so that they are stored in a secure location and are quickly available and can be centrally maintained, for example in the event that the test procedure needs to be adapted.

The measured values recorded in steps 58 and 60 are then combined in step 62 to form a reference signal. The reference signal serves as a signal-based reference for an intrusive check of the elevator system 10.

In step 64, a relation signal is formed on the basis of the current measured values recorded in step 56 and the reference signal formed in step 62, which relates the current measured values and the reference signal to one another and represents agreements or deviations between the data groups involved. For example, the relation signal can be formed as a correlation signal.

In step 66, the relation signal is evaluated and examined for correspondences between the reference signal and the current measured values. A machine learning model is preferably used for this purpose, such as a neural network or a comparable model. In step 68, the evaluation result obtained in step 66 is evaluated. In particular, the 2 described test parameters 40 in order to draw conclusions about the operational safety of the elevator system 10. All of the 2 and 3 The data processing steps described can be carried out by the evaluation unit of the first test device 24. The test of the driving ability can thus be carried out particularly quickly and at the same time very reliably.

LIST OF REFERENCE SYMBOLS

10

Elevator system

12

Car

14

Counterweight

16

Carrying means

18

Traction sheave

20

Deflection pulley

22

Suspension section

24

Test device

27

Distance

28

Test device

29

Floor section

30

Distance

31

Elevator shaft

32

Measurement values of the sensor unit

33

Ceiling section

34

Measurement values of the elevator system

36

Filtering the measured values

38

Determining the test parameter

40

Test parameters

54

Test device

56

Recording of current measured values

58

Recording of reference measurements

60

Entering manufacturer measurements

62

Creating a reference signal

64

Forming a relation signal

66

Evaluating the relation signal

68

Evaluating the evaluation results

Claims (14)

Method for checking an elevator system with a rotatably mounted traction sheave, comprising: - operating the elevator system (10) according to a predefined operating sequence, wherein at least one movable element (12, 14, 16) of the elevator system (10) is moved by driving the traction sheave (18); - detecting a plurality of distance values (32) while the movable element (12, 14, 16) is moved, wherein the distance values each represent a distance (30) between the movable element (12, 14, 16) and a stationary element (31, 33, 29) of the elevator system (10); and - determining at least one test parameter (40) on the basis of the plurality of distance values (32), wherein the test parameter represents the driving ability of the traction sheave (18). Procedure according to Claim 1 , wherein the movable element (12, 14, 16) is formed by a first load element (12) which is connected to a second load element (14) of the elevator installation (10) via at least one support means (16), wherein the support means (16) is deflected and driven between the first load element (12) and the second load element (14) by means of the drive pulley (18) in order to move the first load element (12) and the second load element (14) simultaneously. Procedure according to Claim 2 , further comprising: - determining at least one mass of a section length (22) of the support means (16), wherein the test parameter (40) is determined as a function of the at least one determined mass. Method according to at least one of the preceding claims, wherein the movable element (12, 14, 16) is formed on a speed limiter or a shaft copy of the elevator installation (10). Method according to at least one of the preceding claims, wherein the distance values (32) are detected with at least one sensor device (24, 28), in particular a mobile sensor device, and wherein the sensor device (24, 28) is arranged on the movable element (12, 14, 16) or on the stationary element (31, 33, 29) of the elevator installation (10). Method according to at least one of the preceding claims, wherein the distance values (32) are detected by several sensor devices (24, 28) arranged on the elevator installation (10), and wherein the detected distance values (32) are corrected. Method according to at least one of the preceding claims, wherein at least one sensor device (24, 28) for detecting the distance values (32) has a transmitter for transmitting a transmission signal and a receiver for receiving a reception signal, wherein the detection of at least one of the distance values (32) comprises: - operating the transmitter to transmit a transmission signal between the movable element (12, 14, 16) and the stationary element (31, 33, 29); - operating the receiver to receive a reception signal; and - comparing the transmission signal and the reception signal. Procedure according to Claim 7 , wherein the transmission signal comprises a laser beam, in particular wherein the sensor device (24, 28) comprises a LIDAR module; or wherein the transmission signal comprises an ultrasonic signal. Method according to at least one of the preceding claims, wherein at least one sensor device (24, 28) for detecting the distance values (32) has an optical image sensor, and wherein image data representing a distance (27, 30) between the movable element (12, 14, 16) and the stationary element (31, 33, 29) is generated with the image sensor and at least one of the distance values (32) is detected as a function of the image data. Method according to at least one of the preceding claims, further comprising: - detecting measured values (34, 56) for a measured variable which differs from the distance (27, 30) between the movable element (12, 14, 16) and the stationary element (29, 33), and wherein the test parameter (40) is determined on the basis of the measured values (34, 56). Method according to at least one of the preceding claims, further comprising: - detecting an acoustic signal at the elevator installation (10) while the movable element (12, 14, 16) is moved, and wherein the test parameter (40) is determined as a function of the acoustic signal. Method according to at least one of the preceding claims, wherein the distance values (32) and/or further measured values are recorded by means of at least one mobile testing device (24, 28), in particular wherein the mobile testing device (24, 28) is moved during the recording of the distance values (32) and/or further measured values. Computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out at least one step of the method according to one of the preceding claims. Mobile testing device (24, 28) for an elevator system with a rotatably mounted traction sheave (18), comprising a sensor unit for detecting a plurality of distance values (32) on the elevator system (10) and an evaluation unit which is designed to determine at least one test parameter (40) which represents the driving ability of the traction sheave (18) on the basis of distance values (32) detected using the sensor unit on the elevator system (10).

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