Method for measuring the braking distance of an escalator or a moving walkway

Abstract

The invention relates to a method for measuring the braking distance (LB) and to a braking distance measurement device (30) for carrying out the method on an escalator (1) or moving walkway. The braking distance measurement device (30) has at least one triggering device (45) which can be connected to the controller (14) of the escalator (1) or moving walkway, an optical sensor (35) and a scale generator (37) which generates a virtual measuring scale (31) while a measurement is being carried out. In order for the braking distance (LB) to be measured accurately, a relative movement sequence of a marking (53, 55) which can be detected on the transport belt (26) is recorded as an image sequence by the optical sensor (35) and the braking distance (LB) is evaluated by means of the image sequence (60) and the virtual measuring scale (31).

Description

[0001] Method for measuring the braking distance of an escalator or moving walkway

[0002] The invention relates to a method for measuring the braking distance of an escalator or a moving walkway, a braking distance measuring device for carrying out this method, and an escalator or a moving walkway with such a braking distance measuring device.

[0003] Escalators and moving walkways are used to transport people and are used in department stores, shopping malls, train stations, airports, and other applications. They feature a conveyor belt that is arranged in a rotating manner within the escalator or moving walkway and can be driven by a drive motor. Because these systems transport people, they are subject to stringent safety requirements, such as those defined in the European standard EN 115-1 or the US standard ASME A17.1 / CSA B44.

[0004] One of these safety regulations concerns the permissible length of the conveyor belt's braking distance. This braking distance inevitably occurs due to the inertia of the moving parts after the drive motor is disconnected from the power supply and a service brake or safety brake (hereinafter referred to as the unspecified brake) of the escalator or moving walk is activated. Most authorities require operators or companies entrusted with the maintenance of these systems to periodically check the braking distance and to service the brake if the braking performance does not meet the applicable standards. To prevent falls by users, the brake must not be applied too tightly. Therefore, the standards also specify a maximum permissible deceleration during braking. For example, ENI 15-1 specifies this for escalators and moving walks at a given nominal speed of 0.75m / s (operating speed) a standard braking distance of the conveyor belt in the range between 0.4m and 1.5m, with the maximum permissible deceleration of 1m / s. 2 must not be exceeded.

[0005] To measure the standard braking distance of a conveyor belt, JP2008265971A proposes a braking distance measuring device and a method for performing this measurement. A linear measuring scale is attached to the conveyor belt, and an optical sensor is temporarily attached to a fixed part of the escalator or moving walkway and connected to the escalator's control system. The conveyor belt is then brought up to operating speed. As soon as the optical sensor detects the leading end of the measuring scale, a stop signal is sent to the control system, and the conveyor belt is decelerated by the brake. The distance traveled by the optical sensor on the measuring scale corresponds to the standard braking distance. This measuring method therefore precisely complies with the ENI 15-1 standard, which stipulates that the braking distance must be measured from the moment the stop signal appears until the conveyor belt comes to a standstill.Furthermore, the standard recommends keeping the standard braking distance as close to the lower limit of the range as possible (in the example 0.4 m).

[0006] The braking distance measurement method described above has the disadvantage that it also records time periods without braking torque, such as the reaction times of the optical sensor, the controller, and the electromechanical switch (contactor or relay) controlled by the controller, as well as the reaction time of the brake from the interruption of the ventilation current until the braking torque begins to take effect. The braking distance measurement method described therefore does not provide measurement results that reflect the actual braking behavior of the brake (braking distance while the braking torque is applied).

[0007] The object of the present invention is to provide a braking distance measuring method which provides more precise measurement results with regard to the actual braking behavior of the brake.

[0008] This task is solved by the following method for measuring the braking distance of an escalator or a moving walkway and by a braking distance measuring device for carrying out this method.

[0009] The escalator or moving walkway in which such a measurement can be performed comprises a conveyor belt, at least one drive motor for driving the conveyor belt, a brake for decelerating the conveyor belt, and a controller. The drive motor and the brake can be controlled by the controller. The method for measuring the braking distance can be used for all known brake types of escalators and moving walkways. To carry out the method, a braking distance measuring device with an optical sensor is arranged in the area of ​​the conveyor belt. Furthermore, the braking distance measuring device comprises at least one triggering device connectable to the controller.

[0010] The arrangement of the braking distance measuring device, in particular the optical sensor, is "static" with respect to the conveyor belt, for example by temporarily attaching it to static components of the escalator or moving walkway. Depending on the design of the braking distance measuring device, the optical sensor does not necessarily have to be attached, but can also be held in the area of ​​the conveyor belt by a maintenance person during the measurement. The optical sensor can be used to detect a clearly identifiable marking on the conveyor belt, and its relative movement can be recorded in an image sequence as the conveyor belt moves relative to the sensor. Furthermore, the braking distance measuring device has a scale generator that generates a virtual measuring scale while a measurement is being performed.

[0011] The braking distance measurement procedure comprises several steps that can be performed in the following order. However, this order is not mandatory; where appropriate, certain steps can be performed before or after other steps, or additional steps, as described in the following paragraphs, can be inserted between these steps.

[0012] In one process step, the optical sensor records the relative movement of a detectable marking on the conveyor belt as an image sequence. In a further process step, the braking distance is evaluated using the recorded image sequence and the virtual measuring scale.

[0013] The generation of the virtual measuring scale by the scale generator is, as described below, dependent on the spatial position of the optical sensor in relation to the marking or conveyor belt and, if applicable, to a fixed fixed point, such as a fixed, prominent corner of the escalator or moving walkway. If the braking distance measuring device is implemented, for example, in a mobile device (smartphone, tablet) using a dedicated application program, the built-in optical sensors (CMOS, LiDAR), and a built-in, three-axis position sensor, the spatial position of the optical sensor can be determined analogously to the image frequency, i.e., for each image in the image sequence. This is done by recording the associated distances and angles to the conveyor belt and, if applicable, to the fixed point for each image, so that the scale generator can generate a virtual measuring scale that is consistently position-corrected, i.e., for each image.Detecting a fixed point can be useful if the optical sensor is not stationary during the measurement process. However, this is not mandatory, as the calibration routine described below uses two reference points that allow the determination of a unique spatial position of the sensor relative to the conveyor belt (even if the reference points move with each other). If the optical sensor of the braking distance measuring device is stationary, e.g., installed on a tripod, a single determination of the spatial position of the optical sensor relative to the conveyor belt is naturally sufficient to generate a virtual measuring scale for the entire image sequence that is correct for the marking (i.e., arranged and calibrated in the plane of movement of the marking).

[0014] As mentioned, the virtual measuring scale in the scale generator is calibrated by a calibration routine using an optically measured distance between two known reference points and a calibration distance. The two reference points and the distance between them are also detected by the optical sensor and are preferably included in each image of the image sequence. The calibration distance represents the actual distance between the known reference points in a plane containing the virtual measuring scale. The virtual measuring scale is calibrated in a ratio of the optically measured distance to the calibration distance.

[0015] In other words, a plane is provided for the virtual measuring scale, in which the marking also moves during the recording of the image sequence. The virtual measuring scale can be modeled on a ruler or a two-dimensional measuring grid, with its scale preferably extending parallel to the direction of movement of the marking. Since the braking distance of the conveyor belt is to be recorded, this plane is preferably a walkable surface of the conveyor belt on which the marking is also present. The marking and the reference points can be painted onto the conveyor belt, for example. Self-adhesive film can also be used instead of paint. As is well known, a conveyor belt has steps or pallets arranged one behind the other, each with a fine gap between each step. These gaps can be used both as markings and as reference points.They serve as reference points because the exact length of the steps or pallets, and thus the distances between the columns, are known. Using well-known image measurement programs and trigonometric calculations based on the recorded spatial position, a perfectly calibrated virtual scale can be generated for the captured image sequence.

[0016] The calibration distance can be entered manually, for example, or retrieved as a stored value from a data storage device. The calibration distance can also be extracted from a digital twin of the escalator or moving walkway. The digital twin is a three-dimensional, virtual image of the physical escalator or moving walkway and contains the corresponding calibration distance, provided, for example, the gaps between the steps or pallets are used as reference points.

[0017] In one embodiment of the method, the braking distance measuring device has a projector through which the virtual measuring scale of the scale generator is statically projected onto the conveyor belt and recorded in the image sequence together with the moving marker during the recording of the relative movement. In the image sequence of the recorded relative movement, the marker now moves along the statically projected, virtual measuring scale. It is also directly visible to the maintenance personnel present on-site, allowing them to determine whether the braking performed deviates significantly from the standard specifications or whether it could be within the standard. A more detailed evaluation of the braking performed is described below.

[0018] In an alternative embodiment of the method, the virtual measuring scale generated by the scale generator is statically copied into the image sequence. Here, too, the marker moves along the static, virtual measuring scale in the image sequence of the recorded relative movement sequence, allowing the braking process to be assessed based on the recorded image sequence.

[0019] In a further alternative embodiment of the method, the virtual measuring scale generated by the scale generator is used solely to measure the path traveled by the marker between two images of the image sequence of the recorded relative movement sequence, taken at different times. In other words, the virtual measuring scale is not visible on the individual images of an image sequence, but is used only to measure the path traveled by the marker. The image sequence is preferably evaluated using known image recognition methods via a difference image and automated measurement using the virtual measuring scale.

[0020] A further step in measuring a braking distance involves bringing the conveyor belt up to a specified speed. The specified speed usually corresponds to the transport speed in normal operation, which is often referred to as the nominal speed. The specified speed can also be faster or slower than the nominal speed if different operating conditions of the service brake are to be tested. Once the specified speed is reached, a stop signal is sent to the control system via the triggering device. The stop signal can be triggered manually, for example by a manual input into the triggering device. However, it is also possible for the stop signal to be generated automatically by the triggering device, for example if the stop signal in the triggering device is triggered when the specified speed is reached.

[0021] In a further process step, the relative movement sequence is recorded using the optical sensor, at least from the stop signal until the conveyor belt comes to a complete standstill. Furthermore, the braking distance measuring device includes an acoustic sensor that records the braking operation noises of the brake synchronously with the optical recording. These braking operation noises represent the actual braking application in chronological order. Since the relative movement sequence was recorded synchronously, the beginning of the braking operation noises can be clearly assigned to a specific image of the relative movement sequence recorded as an image sequence. To determine the braking distance, a subsequent image from the recorded image sequence of the movement sequence must be selected, which was clearly recorded at a time when braking operation noises were no longer occurring.If the two images are now compared, the braking distance traveled during the actual use of the brake can be determined from the different positions of the marking on the virtual measuring scale.

[0022] The braking distance measured in this way, for example, allows the average deceleration of the brake to be calculated more precisely. It is also possible to record a braking curve (distance / time diagram, where time is defined by the number of frames per second) by evaluating the traveled braking distance step by step from frame to frame, from which the maximum deceleration can be determined. Based on these measurement results, the brake can be adjusted close to the maximum permissible deceleration. This minimizes the actual braking distance without exceeding the specified maximum deceleration value.

[0023] Measuring the braking distance during actual brake application also offers advantages when diagnosing the technical condition of the escalator or moving walkway. For example, the condition of the brake pads and / or their change compared to previous measurements can be assessed more precisely. Furthermore, the time at which the stop signal is triggered can also be recorded, allowing an image from the recorded image sequence to be assigned to it. If the optical recording of the movement sequence begins with the stop signal, it is logically the first image. The reaction time of the braking system until the brake actually applies a braking torque, and the distance traveled in this process, can now be determined by comparing the two recording times of this first image and the image with the start of the braking operation noise.The distance traveled by the marker, referred to as the reaction length, can also be determined using these two images. A reaction time or reaction length that is too long compared to empirical values ​​may indicate that, for example, the contactors mentioned above need to be replaced. As mentioned at the beginning, the ENI 15-1 standard stipulates that the braking distance must be measured from the moment the stop signal is triggered until the conveyor belt comes to a complete standstill. This standard braking distance can be determined by simply adding the reaction length and the braking distance.

[0024] The evaluation can be carried out entirely manually, but this is very time-consuming. In a further development of the method, the recording of the relative movement and the recording of the synchronously recorded braking noises are displayed parallel to one another in the image sequence as a graphically displayed audio track. This makes it much easier to identify the two or three relevant images of an image sequence described above. The images can also be assigned automatically based on the chronological sequence of the braking noises by reading out the recording times. The assignment is achieved, for example, by automatically determining the start and end of braking application based on the level of the recorded braking noises and then marking the corresponding images with a marker based on the chronological assignment.Corresponding program steps can be implemented in the evaluation software of the braking distance measuring system. The steps described below can be performed either manually by the maintenance personnel or automatically using program steps implemented in the evaluation software.

[0025] A starting position of the marker relative to the measuring scale is then extracted from the image sequence using a starting point of the braking noise. Furthermore, an end position of the marker relative to the virtual measuring scale is also extracted from the absence of the braking noise. The image containing the end position can also be defined using a fixed end position, at which braking noise will definitely no longer occur, since once the conveyor belt stops, braking noise no longer exists and all subsequent images in the image sequence look exactly the same.

[0026] In an alternative development of the invention, the determination of the starting position and the end position from the graphically displayed braking noise or the soundtrack can be carried out automatically using an image processing program implemented in the evaluation software. The image processing program uses known image analysis methods and algorithms known from the electronic processing of video sequences. These analysis algorithms are based, for example, on known image processing techniques that are optimized and applied in self-learning processes using artificial intelligence in neural networks. A common image processing technique for generating information from an image is, for example, the calculation of a histogram, which provides information about the statistical brightness distribution in the image.Such a histogram can, for example, serve as a configuration for further image processing steps or as information for a human user of a software. Other calculable information about an image includes its entropy or average brightness. Based on this information, vector analyses can be carried out to determine how individual prominent points shift relative to one another, and from this, conclusions can be drawn about movement scenarios of the marker relative to the measuring scale. Using the aforementioned methods, for example, an image analysis of the audio track visually displayed in the image sequence can be performed. The image in the image sequence containing the starting point of the braking noise and one of the images in the image sequence in which the absence of the braking noise can be clearly identified can be marked in the image sequence.As already mentioned, an analysis of the noise level of the recorded braking operation noise can also be carried out so that the time of the start and end of braking operation can be determined and the corresponding images from the image sequence can be identified via the temporal assignment.

[0027] In a further automation step of the present method, the distance between the start position and the end position is determined by comparing the two correspondingly marked images of the image sequence. This distance corresponds to the braking distance traveled during the application of the brake. The different positions of the marking relative to the virtual measuring scale can be read, for example, by optical character recognition (OCR) of numbers applied to the virtual measuring scale, and the braking distance can be determined by subsequently calculating the difference. Alternatively, the two images of the image sequence can also be superimposed (difference image), and the distance between the two markings depicted thereon can be measured using the virtual measuring scale. In one embodiment of the invention, the triggering device is connected to the controller.The triggering device retrieves operating data from the drive motor from the control system, whereby a stop signal is sent to the control system as soon as the drive motor has reached a speed that corresponds to the specified speed of the conveyor belt.

[0028] In a further embodiment of the invention, the stop signal can be manually input into the triggering device, for example, by pressing a pushbutton or via a keypad on the triggering device. As soon as the stop signal is input, it is transmitted directly from the triggering device to the control system. Further commands can be transmitted to the control system via the keypad, which can also be generated on a touch-sensitive screen on the triggering device. For example, the start command can be entered via the keypad so that the control system sets the conveyor belt in motion. Furthermore, the conveying direction or the direction of movement of the conveyor belt can also be entered via the keypad.It is also possible for the control system to transmit operating data of the escalator or moving walk, such as the current speed, to the triggering device, which can then be displayed on the screen. The control system can also transmit safety-relevant messages to the triggering device, so that, for example, a refusal of the start command and the underlying cause can be displayed on its screen.

[0029] In summary, the braking distance measuring device for carrying out the method described above comprises at least one triggering device connectable to the controller, a scale generator for generating a virtual measuring scale, an optical sensor, and an acoustic sensor. The optical sensor, the acoustic sensor, and the triggering device are preferably part of a smartphone or tablet with a suitable software application (computer program). The software application comprises at least program steps that provide a scale generator for generating a virtual measuring scale and that enable synchronous recording of a relative movement of the arranged or defined marking to the virtual measuring scale and of the braking operation noise. The software application can also contain program sections by means of which the image processing and calculations described above can be carried out.Furthermore, a wired or wireless connection to a control system of an escalator or moving walkway can be temporarily created.

[0030] Optionally, the braking distance measuring device includes a holder for the smartphone or tablet, which can be temporarily mounted on a fixed part of an escalator or moving walkway. This fixed part can be, for example, a balustrade or a balustrade base, or a floor covering of the escalator or moving walkway. If the braking distance measuring device includes a projector device for projecting a virtual measuring scale, the holder can also have a receptacle for the projector device.

[0031] To ensure high-quality recording of braking noise, the optical sensor and the acoustic sensor of the braking distance measuring device are preferably located in the drive area of ​​the escalator or moving walkway. In an escalator, the drive area is typically located in the upper access area, so that the conveyor belt is primarily subjected to tensile forces. Typically, the drive motor, a drive shaft, a gearbox, and the brake are located in the drive area beneath a walkable floor covering. This walkable floor covering allows access to and exit from the escalator's conveyor belt. Moving walkways are designed in a similar manner.

[0032] As already mentioned above, there are various options for arranging the marking or defining it using existing, prominent points on the escalator or moving walkway. The marking can be an existing contour of the conveyor belt, but also a temporarily attachable object such as a sticker, a colored dot, etc. To simplify handling for the maintenance personnel entrusted with the measurement, the marking is preferably predefined by selecting a prominent contour. In this case, the marking could be, for example, a gap between two escalator steps of the escalator's conveyor belt or a gap between two pallets of the conveyor belt of the moving walkway. Of course, a marking that can be temporarily applied to the conveyor belt can also be used, such as a line drawn with a waterproof felt-tip pen that extends perpendicular to the direction of movement of the conveyor belt.

[0033] Embodiments of the invention are described below with reference to the accompanying drawings, whereby neither the drawings nor the description are to be interpreted as limiting the invention. The figures are merely schematic and not to scale. Identical or equivalent features have the same reference numerals. They show:

[0034] Figure 1: schematic sectional side view of an escalator and its main components;

[0035] Figure 2: a three-dimensional partial view of the drive area shown in Figure 1 with a first possible arrangement of a braking distance measuring device;

[0036] Figure 3 : in three-dimensional partial view of the in Figure 1 designated

[0037] Drive area with a second possible arrangement of a braking distance measuring device;

[0038] Figure 4: schematically shows a smartphone with a software application through which the smartphone can be used as a component of the braking distance measuring device and wherein the software application provides a scale generator;

[0039] Figure 5 : an image from an image sequence taken by an optical sensor of a

[0040] braking distance measuring device shown in Figures 1 to 3;

[0041] Figure 6A: a first image from an image sequence recorded by the braking distance measuring device at the time of input of a stop signal;

[0042] Figure 6B: a second image from the same image sequence at the time of a starting point at which parallel recorded braking noises begin; and Figure 6C: a third image from the same image sequence at the time of an end position at which parallel recorded braking noises end.

[0043] Figure 1 shows a schematic, cross-sectional side view of an escalator 1 and its main components. Escalator 1 can be used to transport people, for example, between two levels E1 and E2 of a building.

[0044] The escalator 1 has a conveyor belt 26 with several escalator steps 3 arranged one behind the other and which can be moved in a direction of movement 6 along a travel path using two conveyor chains 5 (only one visible in Figure 1) arranged in a closed ring and arranged parallel to each other. The double arrow of the direction of movement 6 indicates that the escalator 1 can transport users both from level E1 to level E2 and in the opposite direction. Each escalator step 3 is attached to the two conveyor chains 5 between them. In order to be able to move the conveyor chains 5, the escalator 1 has a drive area 13 in which a drive shaft 17, a gear 16, a drive motor 19, and a brake 18 are arranged. The escalator 1 can have various brake types, for example the service brake shown in Figure 1, which is usually designed as a shoe brake or band brake.In addition, the escalator may also have a safety brake, as disclosed, for example, in W02014 / 009227A1.

[0045] The drive area 13 is usually located on the upper level E2 of the structure, while a tensioning station 7 (shown only schematically) with a deflection shaft 15 is located on the lower level E1. The drive shaft 17 and the deflection shaft 15, as well as other load-bearing components of the escalator 1, are held in a supporting structure 2, usually in the form of a truss structure, which is shown only as an outline in Figure 1 for reasons of clarity. The escalator 1 also has two balustrades 8 (only one visible), each of which has a handrail 4 arranged circumferentially.

[0046] During an upward movement direction 6, the escalator steps 3 are moved in the forward travel from a lower access area 10 of the escalator 1 adjacent to the lower level El, via a central inclined area 11, to an upper access area 12 adjacent to the upper level El, and then moved back in the opposite direction during the return travel.

[0047] The drive motor 19 and the brake 18 arranged in the drive area 13 are controlled and regulated by a controller 14. The torque or the rotational movement of the motor shaft (concealed by the gear box) of the drive motor 19 is transmitted to the drive shaft 17 via the gear box 16 (shown as an example is a worm gear and a drive chain). Since two conveyor chains 5 are usually present, between which the escalator steps 3 are arranged, the drive shaft 17 must also have two drive sprockets (not shown in detail), over which the conveyor belt 26 is guided in a motion-transmitting manner. All components of the drive area 13 are also housed in the supporting structure 2 and are spanned by a walkable floor cover 9, which is a component of the upper access area 12.

[0048] Furthermore, a braking distance measuring device 30 for measuring the braking distance is arranged in the drive area 13 of the escalator 1. In the present embodiment, the braking distance measuring device 30 is temporarily installable, meaning it can be installed, used, and removed again as needed. However, a permanent installation of the braking distance measuring device 30 is also conceivable, for example, in a balustrade base 20 of the balustrade 8.

[0049] Figure 2 shows a three-dimensional, enlarged partial view of the drive area 13 designated in Figure 1 with a first possible arrangement of a braking distance measuring device 30 installed there. The braking distance measuring device 30 has a projector 34 for projecting a virtual measuring scale 31 and a smartphone 32 with an optical sensor 35 and an acoustic sensor 36. Furthermore, the braking distance measuring device 30 comprises a holder 33 for the smartphone 32 and the projector 34. A software application 38 is installed in the smartphone 32, which provides a scale generator 37 and evaluation algorithms for image analyses and position calculations, incorporating the smartphone's own hardware. The function of the scale generator 37 is described further below with reference to Figure 3. In the present embodiment, the virtual measuring scale 31 generated by the scale generator 37 is projected onto the conveyor belt 26 by the projector 34.The virtual measuring scale 31 is arranged in the drive area 13, parallel to the direction of movement 6, with respect to its longitudinal extent. The projector 34 projects the virtual measuring scale 31 over more than one escalator step 3 of the conveyor belt 26.

[0050] In the present embodiment, the holder 33 has concealed suction cups that fix the holder 33 to a cladding panel 21 of the balustrade base 20. The smartphone 32 rests on the holder 33, wherein the holder 33 is arranged on the cladding panel 21 in such a way that the optical sensor 35 of the smartphone 32 can detect both the virtual measuring scale 31 and at least two escalator steps 3 of the conveyor belt 26. Since the brake 18 is located below the floor cover 9, this arrangement also ideally positions the acoustic sensor 36 (see Figure 4) of the smartphone 32 for recording braking operating noises 51 (see Figures 6A to 6C).

[0051] Figure 3 shows a three-dimensional, enlarged partial view of the drive area 13 shown in Figure 1 with a second possible arrangement of a braking distance measuring device 30. This is implemented entirely in a smartphone 32. The use of a conventional smartphone 32 is suitable because it has sufficient computing power and storage capacity for storing and processing the software application 38 and has an optical sensor 35, an acoustic sensor 36, and a touch-sensitive screen 39. In the second arrangement, a scale generator 37 is also implemented in the software application 38.

[0052] To carry out the measuring method, a maintenance person holds the smartphone 32 in the drive area 13 such that at least two stages 3 of the conveyor belt 26 can be detected simultaneously by the optical sensor. First, two reference points RI, R2 are determined or defined by, for example, the maintenance person marking the two reference points RI, R2 on the first image of the image sequence 60 by finger pressure via the touch-sensitive screen 39 at the beginning of a recording of an image sequence 60 (see Figures 6A to 6C). Of course, the reference points RI, R2 can also be automatically suggested by program steps of the software application 38 if they are defined therein and the reference points RI, R2 are recognized and determined in the recorded image using image recognition algorithms or at least suggested to the maintenance person for confirmation (see also Figure 5).After the reference points RI, R2 have been determined, the spatial position of the optical sensor 35 is measured using the two vectors VI, V2, taking into account position data from a three-axis position sensor 40 built into the smartphone 32 and the associated angle α (for clarity, only one of the angles required for position determination is shown). A distance Lo between the two reference points RI, R2 is also optically recorded. Using a calibration routine 95 of the scale generator 37, which uses the optically recorded distance Lo and a calibration distance LK for this purpose, the virtual scale 31 can be calibrated to a reference plane BE of the conveyor belt 26. Furthermore, optically recorded dimensions can be scaled on the reference plane BE.In the present exemplary embodiment, the calibration distance LK corresponds to the length of an escalator step 3, since the two reference points RI, R2 were defined on two columns 28 of the conveyor belt 26 and the adjacent balustrade base 20. The calibration distance LK can, for example, be entered manually or retrieved as a stored value from a data storage 88 of the smartphone 32. However, the calibration distance LK can also be extracted from a digital twin 98 (see Figure 4) of the escalator 1 or the moving walkway. The digital twin 98 is a three-dimensional, virtual image of the physical escalator 1 or the physical moving walkway and contains the corresponding calibration distance LK, provided, for example, the columns 28 between the steps 3 or pallets are used as reference points RI, R2.

[0053] The measurement and calibration described above can only be carried out once for the first possible arrangement shown in Figure 2, since the smartphone 32 is fixed stationary to the escalator 1 by the holder 33 and the spatial position relative to the conveyor belt 26 does not change.

[0054] For the second possible arrangement shown in Figure 3, the corresponding measurement and calibration is preferably performed for each image 61, 62, 63 of an image sequence 60 (see Figures 6A to 6C), because the smartphone 32 is held by the maintenance person and the spatial position of the optical sensor 35 relative to the conveyor belt 26 is therefore constantly changing. Since the two reference points RI, R2 are arranged in the reference plane BE of the conveyor belt 26, coordinates K1, K2, K3, K4 for the virtual scale 31 in the specified reference plane BE can also be easily calculated from the data obtained from the measurement.

[0055] In the first arrangement according to Figure 2, the image data for displaying the virtual scale 31 are calculated for the coordinates K1, K2, K3, K4 and sent to the projector 34 via a data connection 49. The projector 34 projects the correctly calibrated virtual scale 31 onto the conveyor belt 26, so that it is optically captured in each image 61, 62, 63 of the image sequence 60.

[0056] In the second arrangement according to Figure 3, the coordinates K1, K2, K3, K4 are used to generate a virtual measuring scale 31 that can be copied into each image of the image sequence. Alternatively, the coordinates K1, K2, K3, K4 can also be used to convert lengths or distances measured from the images 61, 62, 63 into the actual lengths, distances, or distances using an image processing program (not shown) integrated in the software application 38. For example, a difference image can be created from two images of the image sequence 60, the distance traveled by a marking 53 applied or defined on the conveyor belt, as shown in the difference image, can be measured using the image processing program, and the distance actually traveled by the marking 53 can be calculated using the conversion described above.

[0057] Figure 4 schematically shows a smartphone 32 with a software application 38, through which the smartphone 32 can be used as a component of the braking distance measuring device 30. In addition, Figure 4 schematically shows the components drive motor 19, brake 18, and controller 14 of the escalator 1 to illustrate their interactions with the smartphone 32. Furthermore, Figure 4 shows a data cloud 99 (cloud) with a digital twin 98, which is the most complete digital image possible of the associated physical escalator 1. As represented by the double arrow 97, the braking distance measuring device 30 can exchange data with the data cloud 99 or with the digital twin 98 via the communication module 47 described below. Through this data exchange, the braking distance measuring device 30 can query system-specific data, such as the calibration distance LK mentioned above.In return, the braking distance measuring device 30 can transfer the results determined from the measurements performed to the digital twin 98 to update its data. Using a determined braking distance LB, for example, simulations can be performed on the digital twin 98 and the current state of critical components such as the brake 18 and the dynamic loads of a braking application on the conveyor belt 26 can be determined. Furthermore, simulations can be used to calculate the operating parameters of the brake 18 with regard to the permissible deceleration and the permissible braking distance for various load cases, determine optimal setting values, and then adjust them on the physical escalator 1. This largely eliminates the need for complex and cost-intensive, iterative steps for adjusting the brake 18.

[0058] As already mentioned, the smartphone 32 has an optical sensor 35 (symbolically represented as a video camera), an acoustic sensor 36 (symbolically represented as a handheld microphone), and a touch-sensitive screen 39 on which graphic buttons 41, 42, 43, 44 and thus manually operable elements of a triggering device 45 can be generated. Furthermore, the smartphone 32 has a communications module 47 through which a data connection can be established to the control 14 of the escalator 1. Since a so-called tablet has the same components and properties, a tablet can also be used instead of the smartphone 32. Of course, generic components that are to be used instead of the smartphone 32 for the braking distance measuring device 30 can also be combined in a device specifically designed and built for the braking distance measuring device 30.It is even possible to arrange the aforementioned components separately from one another in the drive area 13, whereby a communication connection 47 must be established, at least temporarily, between the triggering device 45, the optical sensor 35, the acoustic sensor 36, and, if applicable, the controller 14. The triggering device 45 can be designed as a handheld device with a pushbutton (not shown) for inputting, for example, a stop signal 46.

[0059] The aforementioned software application 38 for the smartphone 32 comprises at least program steps that enable synchronous recording of a relative movement of a marking 53, 55 to the virtual measuring scale 31 and the braking operating noises 51 of the brake 18 (see Figures 6A to 6C). The software application 38 also comprises program steps that provide a scale generator 37 with the functions mentioned above, in particular the generation of a virtual measuring scale 31 calibrated to a reference plane BE (see Figures 2 and 3). Further explanations of the virtual measuring scale 31 and the aforementioned marking 53, 55 can be found below in the description of Figures 5 and 6A to 6C.

[0060] The software application 38 has program steps by means of which the required graphic buttons 41, 42, 43, 44 and / or graphic representations 48 of operating data can be generated on the screen 39 following the process sequence. In the present exemplary embodiment, a first button 41 serves to set the escalator 1 (see also Figure 1) in motion with a direction of movement 6 from the lower floor E1 to the upper floor E2. With a second button 42, the escalator 1 can be set in motion with a direction of movement 6 from the upper floor E2 to the lower floor E1.

[0061] In a central area of ​​the touch-sensitive screen 39, a graphical representation 48 can be created and displayed through further program steps of the software application 38. The measurement data required for this are transmitted from the controller 14 via the communication module 47 to the smartphone 32 serving as the triggering device 45. The graphical representation 48 of the exemplary embodiment shows the acceleration behavior of the conveyor belt 26 from standstill Vo to the nominal speed VN. As soon as the nominal speed VN is reached, a stop signal 46 can be entered via a third button 43 of the triggering device 45 and sent to the controller 14 of the escalator 1.With the input of the stop signal 46, the optical sensor 35, the acoustic sensor 36 and the scale generator 37 are simultaneously activated to record an image sequence 60 and an associated sound track 65 and to generate a virtual measuring scale 31 (see Figures 5 and 6A to 6C).

[0062] The stop signal 46 is immediately processed by the control 14 so that the

[0063] The drive motor 19 is disconnected from a power supply (not shown), and the brake 18 is activated by switching off a ventilation current. As soon as the brake shoes 18' of the brake 18 engage, a loud braking noise 51 is released with a decreasing tendency, and this continues until the conveyor belt 26 (see Figure 1) comes to a standstill. At this point, it should be noted that the braking noise 51 of a service brake and a safety brake can differ, particularly when the braking noise 51 fades away. However, what all brake types have in common is that the onset of the braking noise 51 is clearly identifiable on the audio track 65. As soon as the conveyor belt 26 comes to a standstill, tapping a fourth button 44 on the triggering device 45 can initiate an evaluation of the measurement results and a determination of a braking distance LB from the measurement performed.The determination of the braking distance LB is shown below using Figures 6A to 6C.

[0064] Figure 5 shows an image 64 from an image sequence 60 recorded by the optical sensor 35 of the braking distance measuring device 30 shown in Figures 1 to 3. Clearly visible is the virtual measuring scale 31 projected onto the escalator steps 3 of the conveyor belt 26 or copied by program steps of the software application 38. Furthermore, the balustrade base 20 is partially visible, in particular a cladding sheet 21 of the balustrade base 20 as well as the floor cover 9 and the comb plate 27.

[0065] As already mentioned above, a marking 53 is defined or, if necessary, a marking 55 is arranged. In the actual arrangement captured in the image, a gap 28 arranged between two escalator steps 3 serves as the marking 53, which moves relative to the fixed, virtual measuring scale 31 as the conveyor belt 26 moves. In other words, the gap 28 is defined as the marking 53. Alternatively, a special marking 55 can also be temporarily applied to the conveyor belt 26, for example the arrow indicated by a broken line, which is preferably applied to one of the escalator steps 3 using a clearly visible color or as a sticker. In order to more precisely determine the optimal triggering time for braking in correlation with the marking 55 passing by the optical sensor 35, several markings 55 can also be applied serially to the conveyor belt 26.It should also be noted that, even in a conveyor belt 26 of a moving walkway, the gap 28 between two pallets can be defined as a marking 53. Due to the very narrow design of pallets, it may be better to provide a temporarily attachable marking 55. Two gaps 28 were also suggested by the software application 38 as reference points RI, R2, since they are very easy to detect visually and the distance between them is known and can be used as the calibration distance LK.

[0066] The method that can be carried out with the braking distance measuring device 30 described above is explained below with reference to Figures 6A to 6C and with the aid of Figures 3 to 5. Figure 6A shows a first image 61 from an image sequence 60 recorded by the braking distance measuring device 30 at the time of input 67 of a stop signal 46. Figure 6B shows a second image 62 from the same image sequence 60 at the time of a starting point 68 at which parallel-recorded braking noises 51 begin. Figure 6C shows a third image 63 from the same image sequence 60 at the time of an end position 69 at which the parallel-recorded braking noise 51 ends.

[0067] The method for measuring the braking distance LB of an escalator 1 or a moving walk comprises, on the one hand, preparatory steps and, on the other hand, measuring and evaluation steps. The preparatory steps include arranging a braking distance measuring device 30 in the drive area 13 above the conveyor belt 26. Possible embodiments of this have already been described above with reference to Figures 2 and 3. Furthermore, the triggering device 45 of the braking distance measuring device 30 is connected to the control system 14 of the escalator 1 in a signal-transmitting manner. The generation of the virtual measuring scale 31 described with reference to Figure 3 can take place before the measuring steps if the optical sensor 35 is arranged stationary, in order to be able to project it onto the conveyor belt 26 with the projector 34 when using a first arrangement according to Figure 2.If no projector 34 is provided and the braking distance measuring method is to be carried out with an arrangement according to Figure 3, the generation of the virtual measuring scale 31 preferably takes place during the execution of the measuring steps described below.

[0068] The measurement steps include the process steps required for recording image sequences 60 and an associated audio track 65 with the braking operation noises 51. Thus, by a manual input on the triggering device 45, the conveyor belt 26 is brought to a predetermined speed Vv, for example, the nominal speed VN. After the predetermined speed Vv is reached, a stop signal 46 is sent to the controller 14 via the triggering device 45. It is also possible for the triggering device 45 to receive operating data from the drive motor 19 from the controller 14 and automatically send a stop signal 46 to the controller 14 as soon as the drive motor 19 has reached a speed that corresponds to the predetermined speed Vv of the conveyor belt 26.

[0069] Upon input of the stop signal 46, the optical sensor 35 begins recording the relative movement sequence between the marking 53 and the displayed or projected virtual measuring scale 31; at least from the stop signal 46 until the conveyor belt 26 comes to a standstill Vo. Synchronously with the optical recording, the audio track 65 with the braking operation noises 51 of the brake 18 is recorded by the acoustic sensor 36 of the braking distance measuring device 30.

[0070] As shown in Figures 6A to 6C, for simpler and clearer evaluation, the recording of the relative movement between the marking 53 and the virtual measuring scale 31 and the synchronously recorded sound track 65 are combined parallel to each other in an image sequence 60.

[0071] The first recorded image 61 of the image sequence 60 can be assigned to the time of input 67 of the stop signal 46. The sound track 65 is not simply a horizontal line, but has a noise level that represents the normal operating noise of the escalator 1 at the rated speed VN. The signal input position 81, shown with a dashed line, at the time of the stop signal 46 can be read and noted on the first image 61 from the position of the marker 53 to the virtual measuring scale 31.

[0072] If, in the present embodiment of Figures 6A to 6C, the sound track 65 is moved with the finger 74 according to the arrow 70 against the fixed mark 75 generated by the software application 38 on the screen 39, the subsequent images of the image sequence 60 are displayed in chronological order on the screen 39.

[0073] As Figures 6A and 6B show, the audio track 65 exhibits a sudden increase in the noise level, which then continuously decreases. This section of the audio track 65 exhibits the braking noise 51. The second image 62 shows the position of the marker 53 relative to the linear measuring scale 31 at a starting point 68 at which the parallel recorded braking noise 51 begins. The second image 62 is displayed when the sudden increase in the noise level coincides with the fixed mark 75. Again, the position of the marker 53 can be read from the virtual measuring scale 31 and recorded as the starting position 82 of the braking noise 51.The distance traveled by the marking 53 between the signal input position 81 and the start position 82 is the reaction length LR, which arises because the control 14 and the components involved in a brake application, such as contactors for interrupting the ventilation current (not shown) and the brake 18 itself, have a certain reaction time.

[0074] The third image 63 of the image sequence 60 shows the position of the marker 53 relative to the linear measuring scale 31 at the time of an end position 69, at which the parallel recorded braking noises 51 end on the audio track 65 and thus the conveyor belt 26 is stationary. The third image 63 is displayed when the noise level of the audio track 65 has dropped to its lowest level. The audio track 65 only has a background noise. Since the conveyor belt 26 is stationary from this point onwards, all subsequent images in the image sequence 60 look exactly the same. Instead of precisely determining the end of the braking noise 51, it is preferable to select an image 63 that reliably reproduces a static state of the conveyor belt 26. This is the case when two images at the end of the image sequence 60 that are separated in time have an identical position of the marker 53 relative to the virtual measuring scale 31.Again, the position of the marking 53 can be read from the virtual measuring scale 31 and recorded as the end position 83.

[0075] However, as Figures 6B and 6C show, the marker 53 defined in Figure 6A disappears when the sound track 65 is moved further with the finger 74 at the lower edge of the image, which is why in Figure 6B the subsequent gap 28 between two escalator steps 3 is alternatively defined as marker 53'. Accordingly, a new starting position 82' is also alternatively read and recorded on the virtual measuring scale 31.

[0076] The distance traveled by the marker 53' between the start position 82' and the end position 83 is the actual braking distance LB during the application of brake 18. As mentioned above, the ENI 15-1 standard stipulates that the braking distance must be measured from the input 67, or from the occurrence of the stop signal 46, until the conveyor belt 26 comes to a complete standstill. This standard braking distance can be determined by simply adding the reaction length LR and the braking distance LB.

[0077] The previously described, primarily manual evaluation of the image sequence 60 can also be carried out automatically using an image processing program by performing an image analysis of the course of the recorded braking noises 51 visually displayed in the image sequence 60 and marking in the image sequence 60 the image of the image sequence 60 containing the starting point 68 of the braking noise 51 and one of the images of the image sequence 60 in which the absence of the braking noise 51 is clearly recognizable. Even in the automated process, the braking distance LB between the starting position 82 and the end position 83 is determined by comparing the two marked images of the image sequence 60. The different positions of the marking 53 relative to the virtual measuring scale 31 are read out, and the braking distance LB is determined by calculating the difference.Of course, this evaluation can also be carried out automatically with comparable steps using the known difference image evaluation using known image processing programs and the virtual measuring scale 31.

[0078] Although escalators are shown in Figures 1 to 3, it is obvious that the braking distance measuring device 30 and the associated method can equally be used for moving walks.

[0079] Finally, it should be noted that terms such as "having," "comprising," etc., do not exclude other elements or steps, and terms such as "a" or "an" do not exclude a plurality. Furthermore, it should be noted that features or steps described with reference to one of the above embodiments may also be used in combination with other features or steps of other embodiments described above. Reference signs in the claims are not to be considered as limitations.

Claims

Patent claims 1. A method for measuring a braking distance (LB) of an escalator (1) or a moving walkway, wherein the escalator (1) or the moving walkway has a conveyor belt (26), at least one drive motor (19) for driving the conveyor belt (26), a brake (18) for braking the conveyor belt (26) and a controller (14), wherein the drive motor (19) and the brake (18) can be controlled by the controller (14) and wherein a braking distance measuring device (30) is arranged at least temporarily in the region of the conveyor belt (26), which comprises at least one triggering device (45) connectable to the controller (14) and an optical sensor (35), characterized in that • that the braking distance measuring device (30) comprises a scale generator (37) which generates a virtual measuring scale (31) while a measurement is being carried out; • that as a result of a movement of the conveyor belt (26), a relative movement sequence of a marking (53, 55) detectable on the conveyor belt (26) is recorded by the optical sensor (35) as an image sequence (60); and • that the braking distance (LB) is evaluated using the image sequence (60) and the virtual measuring scale (31).

2. The method according to claim 1, wherein • the conveyor belt (26) is brought to a predetermined speed (Vv); • after reaching the predetermined speed (Vv) a stop signal (46) is sent to the controller (14) by means of the triggering device (45); • the recording of the relative movement sequence is carried out at least from the stop signal (46) until the conveyor belt (26) comes to a complete standstill by means of the optical sensor (35); and • the braking distance measuring device (30) also comprises an acoustic sensor (36) which records the braking operating noises (51) of the brake (18) synchronously with the optical recording.

3. Method according to claim 1 or 2, wherein in the scale generator (37) the virtual measuring scale (31) is calibrated by a calibration routine (95) by means of an optically detected distance (Lo) between two known reference points (RI, R2) and a calibration distance (LK), wherein the calibration distance (LK) represents the actual distance between the known reference points (RI, R2) in a reference plane (BE) containing the virtual measuring scale (31) and the virtual measuring scale (31) is calibrated in a ratio of the optically detected distance (Lo) to the calibration distance (LK).

4. The method according to claim 3, wherein the calibration distance (LK) is entered manually or the calibration distance (LK) is retrieved as a stored value from a data memory (88) or the calibration distance (LK) is extracted from a digital twin (98) of the staircase (1) or the ascent.

5. Method according to one of claims 1 to 4, wherein the braking distance measuring device (30) comprises a projector (34) by means of which the virtual measuring scale (31) of the scale generator (37) is statically projected onto the conveyor belt (26) and is recorded together with the moving marking (53, 55) during the recording of the relative movement sequence, such that in the image sequence (60) of the recorded relative movement sequence the marking (53, 55) moves along the statically projected, virtual measuring scale (31).

6. Method according to one of claims 1 to 4, wherein the virtual measuring scale (31) generated by the scale generator (37) is statically inserted into the image sequence (60) such that in the image sequence (60) of the recorded relative movement sequence the marking (53, 55) moves along the static, virtual measuring scale (31).

7. Method according to one of claims 1 to 4, wherein the virtual measuring scale (31) generated by the scale generator (37) is used to measure the path traveled by the marking (53, 55) between two images (61, 62, 63) of the image sequence (60) of the recorded relative movement sequence.

8. The method according to one of claims 2 to 7, wherein a start position (82, 82') of the marking (53, 55) relative to the virtual measuring scale (31) is extracted from the image sequence (60) by means of a start point (68) of the braking operation noise (51), and an end position (83) of the marking (53, 55) relative to the virtual measuring scale (31) is extracted from the omission of the braking operation noise (51).

9. The method according to claim 8, wherein the determination of the braking distance (LB) between the starting position (82, 82') and the end position (83) is carried out by means of an image comparison of the image (62) containing the starting position (82, 82') and the image (63) of the image sequence (60) containing the end position (83), by reading out the different positions of the marking (53, 55) relative to the virtual measuring scale (31) and determining the braking distance (LB) by forming the difference.

10. Method according to one of claims 1 to 9, wherein the triggering device (45) is connected to the controller (14) and receives operating data of the drive motor (19) therefrom, wherein a stop signal (46) is sent to the controller (14) as soon as the drive motor (19) has reached a speed which corresponds to the predetermined speed (Vv) of the conveyor belt (26).

11. Method according to one of claims 1 to 9, wherein a stop signal (46) can be manually input into the triggering device (45), which stop signal (46) is transmitted directly from the triggering device (45) to the controller (14).

12. Braking distance measuring device (30) for carrying out the method in an escalator (1) or a moving walkway according to one of claims 1 to 11, characterized in that the braking distance measuring device (30) comprises at least one triggering device (45) connectable to the controller (14), a scale generator (37) for generating a virtual measuring scale (31), an optical sensor (35) and an acoustic sensor (36).

13. Braking distance measuring device (30) according to claim 12, wherein the optical sensor (35), the acoustic sensor (36) and the triggering device (45) are part of a smartphone (32) or tablet with a software application (38), wherein the software application (38) comprises at least program steps which provide a scale generator (37) for generating a virtual measuring scale (31) and enable a synchronous recording of a relative movement of the marking (53, 55) to the virtual measuring scale (31) and of the braking operating noises (51).

14. Braking distance measuring device (30) according to claim 13, wherein it comprises a holder (33) for the smartphone (32) or tablet, which holder (33) can be temporarily arranged on a fixed part of an escalator (1) or a moving walkway.

15. Escalator (1) or moving walkway comprising a braking distance measuring device (30) according to one of claims 12 to 14, wherein a marking (53) detectable by the optical sensor (35) of the braking distance measuring device (30) is a gap (28) between two escalator steps (3) of the conveyor belt (26) of the escalator (1), or a gap (28) between two pallets of the conveyor belt (26) of the moving walkway, or a marking (55) temporarily attachable to the conveyor belt (26).

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