Escalator clamping detection system

Abstract

An escalator system is provided and includes a comb plate; a moving step, the moving step being drivable to move in a conveying direction along the comb plate to pass through the comb plate at a step-comb plate interface; and a pinch monitoring and detection system. The pinch monitoring and detection system includes: a sensor disposed at the step-comb plate interface and configured to sense a presence of an object at the step-comb plate interface; and a processor configured to determine whether the sensor senses that the object is present at the step-comb plate interface for a predetermined time.

Description

Technical Field

[0001] The present disclosure relates to escalator systems, and more particularly to systems and methods that provide LiDAR-based traffic monitoring and entrapment detection. Background Art

[0002] People conveying devices such as escalators and moving walkways generally include: a conveyor belt that moves between opposite landing areas with people standing on it; a drive machine that drives the movement of the conveyor belt and comb plates. The conveyor belt extends and moves between opposite landing areas and has a surface that generally includes a cleat and a groove. The comb plates are arranged at the opposite landing areas. Each comb plate includes teeth that extend into the grooves of the surface of the conveyor belt when the conveyor belt moves relative to each comb plate, and the cleat moves along each tooth.

[0003] Foreign objects (such as wiring, human body parts and bent splints) getting caught at the comb plates can cause operational problems and damage.Therefore, there is a need for a system and method that provides traffic monitoring and entrapment detection for comb plates to allow reliable detection of entrapment events. Summary of the invention

[0004] According to one aspect of the present disclosure, an escalator system is provided and includes: a comb plate; a moving step that is drivable to move along the comb plate in a conveying direction to pass through the comb plate at a step-comb plate interface; and a clamping monitoring and detection system. The clamping monitoring and detection system includes: a sensor that is disposed at the step-comb plate interface and is configured to sense the presence of an object at the step-comb plate interface; and a processor that is configured to determine whether the sensor senses the presence of the object at the step-comb plate interface for a predetermined time.

[0005] According to an additional or alternative embodiment, the comb plate comprises teeth and the movable step comprises alternating grooves and clamps, and the movable step is drivable to move along the comb plate in the conveying direction so that the teeth pass through the grooves at the step-comb plate interface.

[0006] According to an additional or alternative embodiment, the sensor is a LiDAR sensor.

[0007] According to an additional or alternative embodiment, the sensor is a RADAR sensor.

[0008] According to additional or alternative embodiments, the sensor is a camera.

[0009] According to additional or alternative embodiments, the sensor is one or more of a LiDAR sensor, a RADAR sensor, or a camera.

[0010] According to additional or alternative embodiments, the sensor is configured to perform periodic sensing and is further configured to generate a signal during the periodic sensing that is receivable and readable by the processor.

[0011] According to additional or alternative embodiments, when no object is present at the step-comb plate interface, the signal is a first signal and reflects the width of the moving step; when an object is present at the step-comb plate interface for less than the predetermined time, the signal deviates from the first signal and lasts for less than the predetermined time; and when an object is present at the step-comb plate interface for at least the predetermined time, the signal deviates from the first signal and lasts for at least the predetermined time.

[0012] According to additional or alternative embodiments, the processor is further configured to determine that the entrapment event is valid based on a positive determination that the sensor senses the object is present at the step-comb plate interface for the predetermined time, and take mitigation actions accordingly; and the mitigation actions include at least one or more of braking or slowing down the escalator system, causing an alarm, and adjusting the comb plate.

[0013] According to one aspect of the present disclosure, an escalator system is provided and includes a comb plate, a moving step, and a clamping monitoring and detection system. The comb plate includes teeth. Each moving step includes alternating grooves and clamps, and can be driven to move along the comb plate in a conveying direction to pass through the comb plate so that the teeth pass through the grooves at the step-comb plate interface. The clamping monitoring and detection system includes: a sensor, which is arranged at the step-comb plate interface and is configured to sense the presence of an object at the step-comb plate interface; and a processor. The processor is configured to determine whether the sensor senses the presence of the object at the step-comb plate interface for a predetermined time, so as to judge that the clamping event is valid and take mitigation actions accordingly based on the positive determination that the sensor senses the presence of the object at the step-comb plate interface for the predetermined time.

[0014] According to an additional or alternative embodiment, the sensor is a LiDAR sensor.

[0015] According to an additional or alternative embodiment, the sensor is a RADAR sensor.

[0016] According to additional or alternative embodiments, the sensor is a camera.

[0017] According to additional or alternative embodiments, the sensor is one or more of a LiDAR sensor, a RADAR sensor, or a camera.

[0018] According to additional or alternative embodiments, the sensor is configured to perform periodic sensing and is further configured to generate a signal during the periodic sensing that is receivable and readable by the processor.

[0019] According to additional or alternative embodiments, when no object is present at the step-comb plate interface, the signal is a first signal and reflects the width of the moving step; when an object is present at the step-comb plate interface for less than the predetermined time, the signal deviates from the first signal and lasts for less than the predetermined time; and when an object is present at the step-comb plate interface for at least the predetermined time, the signal deviates from the first signal and lasts for at least the predetermined time.

[0020] According to additional or alternative embodiments, the sensor is configured to be a sensor respectively arranged at multiple positions at or near the step-comb plate interface and configured to sense the presence of an object at the multiple positions at or near the step-comb plate interface; and the processor is configured to determine whether the sensor senses the presence of the object at the multiple positions at or near the step-comb plate interface.

[0021] According to one aspect of the present disclosure, there is provided a method of operating a clamping monitoring and detection system for an escalator system, wherein a moving step passes a comb plate at a step-comb plate interface. The method comprises: scanning the step-comb plate interface; determining whether the result of the scanning indicates that an object is at the step-comb plate interface; determining whether the result of the scanning indicates that the object is at the step-comb plate interface for a predetermined time; and judging that clamping is valid based on the result of the scanning indicating that the object is at the step-comb plate interface and for the predetermined time.

[0022] According to additional or alternative embodiments, the method further includes determining escalator traffic by counting the total number of times an object persists at the step-comb plate interface for less than the predetermined time and the number of times an object persists at the step-comb plate interface for at least the predetermined time.

[0023] According to additional or alternative embodiments, the method further includes taking mitigating action to resolve the entrapment, the mitigating action including at least one or more of braking or slowing the escalator system, sounding an alarm, and adjusting the comb plate.

[0024] Additional features and advantages are achieved through the technology of the present disclosure. Other embodiments and aspects of the present disclosure are described in detail herein and are considered to be part of the claimed technical concept. In order to better understand the present disclosure with the advantages and features, reference is made to the specification and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in conjunction with the accompanying drawings and detailed description, wherein like reference numerals represent like parts:

[0026] Figure 1 is a perspective view of an escalator system according to an embodiment;

[0027] Figure 2 According to the embodiment Figure 1 An enlarged perspective view of a landing of an elevator system;

[0028] Figure 3 is a side view of components of an escalator system having an entrapment monitoring and detection system according to an embodiment;

[0029] Figure 4A According to the embodiment Figure 3 An enlarged side view of the step-comb plate interface of an escalator system and a sensor of a clamping monitoring and detection system;

[0030] Figure 4B According to the embodiment Figure 4A A top view of the step-comb plate interface;

[0031] Figure 5 Yes Figure 3 and a graphical depiction of the operation of an escalator system having an entrapment monitoring and detection system of FIG. 4 ; and

[0032] Figure 6 is a flow chart illustrating a method of operating an entrapment monitoring and detection system for an escalator system according to an embodiment. DETAILED DESCRIPTION

[0033] In escalator technology, passenger safety risks are associated with riding an escalator. These include overcrowding, which can cause passengers to trip and personal items (such as shoes, shoelaces or clothing) to become caught at the interface of the moving steps and the comb plates.

[0034] Therefore, as will be described below, a method and system are provided to monitor and identify both types of risks. A light detection and ranging (LiDAR) sensor, or another similar type of sensor, is mounted at the step-comb plate interface. The sensor emits a light beam that effectively detects the nearest object in its path. When no passengers are present, the sensor returns a signal reflecting the width of the escalator (i.e., the distance to the opposite wall). When an object is at the step-comb plate interface for a certain period of time, the object obscures the sensor. The sensor then returns a signal reflecting the distance to the object, and the system infers a entrapment event. Reference Figure 1 , an escalator 10 is provided. In the subsequent description, it should become clear that the present invention is applicable to other passenger conveyor systems, such as moving walkways. The escalator 10 generally includes a truss 12 extending between a lower landing 14 and an upper landing 16. A plurality of sequentially connected steps or pallets 18 are connected to a step chain 20 and travel through a closed loop path within the truss 12. A pair of handrails 22 are provided on either side of the escalator 10, wherein each handrail 22 includes a moving handrail 24. A drive machine 26 or drive system is generally located in a machine space 28 below the upper landing 16. An additional machine space 28' may be located below the lower landing 14. The drive machine 26 is configured to drive the pallets 18 and / or handrails 24 through the step chain 20. Under normal operating conditions, the drive machine 26 operates to move the pallets 18 in a selected direction at a desired speed.

[0035] The step 18 makes a 180 degree course change in a turnaround area 19 located below the lower landing 14 and the upper landing 16. The step 18 is pivotally attached to a step chain 20 and runs along the closed loop path of the step chain 20 from one landing to another and back again.

[0036] The drive machine 26 includes a first drive member 32 (e.g., a motor output pulley) connected to a drive motor 34 via a belt reduction assembly 36, which includes a second drive member 38 (e.g., an output pulley) driven by a tension member 39 (e.g., an output belt). In some embodiments, the first drive member 32 is an active driving member and the second drive member 38 is a passive driving member.

[0037] As used herein, in various embodiments, the first drive member 32 and / or the second drive member 38 can be any type of rotating device, such as a pulley, a pulley, a gear, a wheel, a sprocket, a gear, a pinion, etc. In various embodiments, the tension member 39 can be configured as a chain, a belt, a cable, a strap, a ribbon, a bar, or any other similar device that operatively connects two elements to provide a driving force from one element to another. For example, the tension member 39 can be any type of interconnecting member that extends between the first drive member 32 and the second drive member 38 and operatively connects them. In some embodiments, as Figure 1 As shown in , the first drive member 32 and the second drive member can provide belt reduction. For example, the diameter of the first drive member 32 can be about 75 mm (2.95 inches), while the diameter of the second drive member 38 can be about 750 mm (29.53 inches). For example, the belt reduction allows the pulley to be replaced to change the speed of 50 or 60 Hz power supply power application, or different stepping speeds. However, in other embodiments, the second drive member 38 can be substantially similar to the first drive member 32.

[0038] As described, the first drive member 32 is driven by the drive motor 34 and is therefore configured to drive the tension member 39 and the second drive member 38. In some embodiments, the second drive member 38 may be an idler gear or similar device that is driven by the operative connection between the first drive member 32 and the second drive member 38 by means of the tension member 39. The tension member 39 travels around a loop set by the first drive member 32 and the second drive member 38, which may be referred to as a small loop hereinafter. The small loop is provided for driving a larger loop consisting of the step chain 20 and is driven, for example, by the output pulley 40. Under normal operating conditions, based on the movement speed of the first drive member 32 as driven by the drive motor 34, the tension member 39 and the step chain 20 move in unison.

[0039] The escalator 10 also includes a controller 115 in electronic communication with the drive motor 34. As shown, the controller 115 can be located in the machine space 28 of the escalator 10 and is configured to control the operation of the escalator 10. For example, the controller 115 can provide a drive signal to the drive motor 34 to control the acceleration, deceleration, stop, etc. of the pedal 18 through the step chain 20. The controller 115 can be an electronic controller including a processor and an associated memory, wherein the associated memory includes computer executable instructions that, when executed by the processor, cause the processor to perform various operations. The processor can be, but is not limited to, a single processor or a multi-processor system of any one of a variety of possible architectures, including a field programmable gate array (FPGA), a central processing unit (CPU), an application specific integrated circuit (ASIC), a digital signal processor (DSP), or a graphics processing unit (GPU) hardware arranged homogeneously or heterogeneously. The memory can be, but is not limited to, a random access memory (RAM), a read-only memory (ROM), or other electronic, optical, magnetic, or any other computer-readable medium.

[0040] Although described herein as a particular escalator drive system and particular components, this is merely exemplary, and those skilled in the art will appreciate that other escalator system configurations may also operate with the invention disclosed herein.

[0041] refer to Figure 2 , Figure 1 The pedal 18 may be provided as a plurality of steps, and Figure 1 The lower station 14 and the upper station 16 of the conveyor belt conveyor may include a floor plate 201. The upper surface of each step (i.e., the tread plate 18) may be provided with a plurality of alternating grooves 202 and cleats 203 extending in the conveying direction C. A comb plate 210 is arranged immediately adjacent to the floor plate 201 on a side of the floor plate 201 facing the steps. The comb plate 210 includes a plurality of teeth 211 extending parallel to the conveying direction C. The teeth 211 are arranged in a staggered relationship with the cleats 203 of the steps and extend into the grooves 202.

[0042] Reference Figure 3-Figure 5 , an escalator system 301 is provided. The escalator system 301 includes a comb plate 410 (see FIG. 4 ), a moving step 320 and a clamping monitoring and detection system 330 .

[0043] The comb plate 410 includes teeth 411 arranged along an edge 412 of the comb plate 410 in the transverse dimension W of the moving step 320. Each of the moving steps 320 includes alternating grooves 321 and clamps 322. Each of the moving steps 320 is drivable to move in a conveying direction C perpendicular to the transverse dimension W, thereby passing through the comb plate 410 at the step-comb plate interface 420. As the moving steps 320 move in the conveying direction C, the teeth 411 pass through the corresponding grooves 321 of each moving step 320 at the step-comb plate interface 420. The clamping monitoring and detection system 330 includes a sensor 331 and a processor 332. The sensor 331 is disposed at or near the step-comb plate interface 420 and is configured to sense the presence of an object at the step-comb plate interface 420 at any point along the transverse dimension W.

[0044] The processor 332 is operably coupled to the sensor 331 and includes a processing unit, a networking unit, and a memory, the processing unit communicating with the sensor 331 and an external device through the networking unit. The memory has executable instructions stored thereon, which, when executed, cause the processing unit to operate as described herein. The following description will generally refer to the processor 332.

[0045] The processor 332 is configured to determine whether the sensor 331 senses the presence of an object at the step-comb plate interface 420 for a predetermined time. In addition, the processor 332 is further configured to determine that the entrapment event is valid based on the positive determination that the sensor 331 senses the presence of an object at the step-comb plate interface 420 for a predetermined time, and take mitigation actions accordingly. According to one or more alternative embodiments, the mitigation actions may include braking or slowing down the escalator system 301, sounding an alarm, and adjusting the comb plate 410 (see Figure 6 ) at least one or more.

[0046] According to an embodiment, sensor 331 may include or be configured as one or more of a light detection and ranging or laser imaging, detection and ranging (LiDAR) sensor, a radio detection and ranging (RADAR) sensor, and / or a camera. According to another embodiment, sensor 310 may be configured as one or more of a 2D LiDAR sensor, a millimeter wave RADAR sensor, and / or a red, green, blue, depth (RGBD) camera. According to still other embodiments, sensor 310 may be configured as a plurality of sensors, including a combination of one or more sensor types listed herein.

[0047] According to Figure 5In another embodiment shown in , the sensor 331 can be configured as a plurality of sensors 331 that sense or scan at similar or different wavelengths at or near the step-comb plate interface 420. In these or other cases, the plurality of sensors 331 can be arranged on the same side of the step-comb plate interface 420 and / or at opposite sides of the step-comb plate interface 420. In the former example, the plurality of sensors 331 arranged on the same side of the step-comb plate interface 420 can be configured to sense or scan in substantially the same or similar directions. In contrast, in the latter case, the plurality of sensors 331 arranged on opposite sides of the step-comb plate interface 420 can be arranged in a coaxial or staggered manner and can be configured to sense or scan in substantially opposite directions.

[0048] The plurality of sensors 331 may be used for redundancy, confirmation of sensing results, and traffic monitoring and detection where an object on the escalator that may not be sensed by one sensor 331 may be sensed by another sensor 331. The plurality of sensors 331 may also be used to infer relative motion of objects, or to assess movement of objects occurring between groups of the plurality of sensors 331. That is, if a foot is placed on the moving step 320, there will be a time delay between an upstream sensor in the plurality of sensors 331 and a downstream sensor in the plurality of sensors 331.

[0049] Also like Figure 5 As shown in FIG. 4A and FIG. 4B (which illustrates data that can be generated by the sensor 331, particularly when the sensor 331 is a LiDAR sensor), the sensor 331 can be configured to perform periodic sensing, and can be further configured to generate data during the periodic sensing as signals S. These signals S can be received and read by the processor 332. When no object is present at the step-comb plate interface 420, the signal S is a first signal S1 and reflects the width W of each moving step in the moving steps 320, which is unchangeable. When an object is present at the step-comb plate interface 420 for less than a predetermined time (which can be any time in the range of a few milliseconds to a few seconds or longer), the signal S deviates from the first signal S1 and continues as a second signal S2 for less than a predetermined time. When an object is present at the step-comb plate interface 420 for at least a predetermined time, the signal S deviates from the first signal S1 and continues as a third signal S3 for at least a predetermined time. As used herein, deviations of the second and third signals S2 and S3 from the first signal S1 appear as data points that reflect not the width W of the moving step 320 , but rather the shorter and variable distance between the sensor 331 and an object present at the step-comb plate interface 420 .

[0050] The processor 332 can be trained or otherwise programmed to use various types of training scenarios and modeling to identify the width W and corresponding distance reflected by the first signal S1, the second signal S2, and the third signal S3. In particular, the processor 332 can be trained or programmed to distinguish the third signal S3 from the first signal S1 and the second signal S2 to determine that the entrapment event is valid based on the third signal S3 and then take mitigation actions.

[0051] It is to be understood that the training of the processor 332 includes training the processor 332 to recognize that certain signal groups will be read together with certain continuity, while other signal groups may not qualify to be read together. This can be achieved by defining a maximum distance between discrete signals and recognizing that discrete signals that are separated from each other by a distance exceeding the maximum distance will not be read together.

[0052] According to additional embodiments, the escalator system 301 may also be configured for traffic monitoring to sense overcrowding of the escalator. In these or other cases, the persistence of the detected object may provide an indication of traffic volume even if the persistence is less than a predetermined time. An object (e.g., a normal step) may persist for 0-250 milliseconds, while an object that persists for more than 250 milliseconds may be considered to indicate a clamping. Therefore, the sensor 331 and the processor 332 may collaboratively monitor traffic volume by counting the number of objects that persist for less than a predetermined time without triggering a mitigation action.

[0053] Reference Figure 6 , a method of operating a clamping monitoring and detection system for an escalator system as described above is provided. The method includes scanning a step-comb plate interface (box 601), determining whether the result of the scan indicates that an object is at the step-comb plate interface (box 602), determining whether the result of the scan indicates that the object is at the step-comb plate interface for a predetermined time (box 603), and judging that a clamping is valid based on the result of the scan indicating that the object is at the step-comb plate interface and for a predetermined time (box 603). In addition, the method may also include taking mitigation actions to resolve the clamping (box 604), such as by braking or slowing the escalator system, causing an alarm, and adjusting the comb plate. According to additional embodiments, the method may further include counting persistence signals (i.e., those signals indicating that the object is at the step-comb plate interface for less than a predetermined time) and clamping (i.e., those signals indicating that the object is at the step-comb plate interface for at least a predetermined time) for the purpose of traffic volume determination (box 606).

[0054] The technical effect and benefit of the present disclosure is to provide a fast-response, retrofittable detection system capable of monitoring and detecting escalator overcrowding and entrapment at the step-comb plate interface at the escalator entrance or exit. The output of the system can be used to count the volume of traffic on the escalator and / or trigger safety-related actions, such as deploying traditional escalator safety brakes or other new safety devices, such as comb plate releases.

[0055] The corresponding structures, materials, actions and equivalents of all parts or steps plus functional elements in the following claims are intended to include any structure, material or action for performing functions in combination with other claimed elements as specifically claimed. For the purpose of illustration and description, the description of the present disclosure has been presented, but it is not intended to be exhaustive or limited to the technical concepts in the disclosed form. Without departing from the scope and spirit of the present disclosure, many modifications and variations will be apparent to those of ordinary skill in the art. The embodiments are selected and described in order to best explain the principles and practical applications of the present disclosure, and to enable other persons of ordinary skill in the art to understand the disclosure of various embodiments with various modifications such as those suitable for the specific purposes contemplated.

[0056] While the preferred embodiment of the disclosure has been described, it will be understood that those skilled in the art, both now and in the future, may make various improvements and enhancements which fall within the scope of the appended claims. These claims should be construed to maintain the proper protection for the disclosure first described.

Claims

1. An escalator system, comprising: Comb plate; a moving step drivable to move along the comb plate in a conveying direction to pass the comb plate at a step-comb plate interface; as well as Entrainment monitoring and detection system, including: a sensor disposed at the step-comb plate interface and configured to sense the presence of an object at the step-comb plate interface; as well as A processor is configured to determine whether the sensor senses the object is present at the step-comb plate interface for a predetermined time.

2. The escalator system according to claim 1, wherein: The comb plate includes teeth, and the moving steps include alternating grooves and cleats; and The moving step is drivable to move along the comb plate in the conveying direction such that the teeth pass through the grooves at the step-comb plate interface.

3. The escalator system according to claim 1, wherein: The sensor is a LiDAR sensor.

4. The escalator system according to claim 1, wherein: The sensor is a RADAR sensor.

5. The escalator system according to claim 1, wherein: The sensor is a camera.

6. The escalator system according to claim 1, wherein: The sensor is one or more of a LiDAR sensor, a RADAR sensor, or a camera.

7. The escalator system according to claim 1, wherein: The sensor is configured to perform periodic sensing and is further configured to generate a signal during the periodic sensing that is receivable and readable by the processor.

8. The escalator system according to claim 7, wherein: When no object is present at the step-comb plate interface, the signal is a first signal and reflects the width of the moving step; When an object is present at the step-comb plate interface for less than the predetermined time, the signal deviates from the first signal for less than the predetermined time; as well as When an object is present at the step-comb plate interface for at least the predetermined time, the signal deviates from the first signal for at least the predetermined time.

9. The escalator system according to claim 1, wherein: The processor is further configured to determine that a entrapment event is valid based on a positive determination by the sensor that the object is present at the step-comb plate interface for the predetermined time, and take mitigation actions accordingly; and The mitigating action includes at least one or more of braking or slowing the escalator system, sounding an alarm, and adjusting the comb plates.

10. An escalator system, comprising: a comb plate including teeth; moving steps each including alternating grooves and clamping plates and drivable to move along the comb plate in a conveying direction past the comb plate such that the teeth pass through the grooves at the step-comb plate interface; as well as Entrainment monitoring and detection system, including: a sensor disposed at the step-comb plate interface and configured to sense the presence of an object at the step-comb plate interface; as well as A processor is configured to determine whether the sensor senses the presence of the object at the step-comb plate interface for a predetermined time, so as to judge that the clamping event is valid and take mitigation actions accordingly based on the affirmative determination that the sensor senses the presence of the object at the step-comb plate interface for the predetermined time.

11. The escalator system according to claim 10, wherein: The sensor is a LiDAR sensor.

12. The escalator system according to claim 10, wherein: The sensor is a RADAR sensor.

13. The escalator system according to claim 10, wherein: The sensor is a camera.

14. The escalator system according to claim 10, wherein: The sensor is one or more of a LiDAR sensor, a RADAR sensor, or a camera.

15. The escalator system according to claim 10, wherein: The sensor is configured to perform periodic sensing and is further configured to generate a signal during the periodic sensing that is receivable and readable by the processor.

16. The escalator system according to claim 10, wherein: When no object is present at the step-comb plate interface, the signal is a first signal and reflects the width of the moving step; When an object is present at the step-comb plate interface for less than the predetermined time, the signal deviates from the first signal for less than the predetermined time; as well as When an object is present at the step-comb plate interface for at least the predetermined time, the signal deviates from the first signal for at least the predetermined time.

17. The escalator system according to claim 10, wherein: The sensors are arranged at a plurality of locations respectively disposed at or near the step-comb plate interface and configured to sense the presence of an object at the plurality of locations at or near the step-comb plate interface; and The processor is configured to determine whether the sensor senses the object's presence at the plurality of locations at or near the step-comb plate interface.

18. A method of operating an entrapment monitoring and detection system for an escalator system wherein a moving step passes a comb plate at a step-comb plate interface, the method comprising: Scanning the step-comb plate interface; determining whether a result of the scanning indicates that an object is at the step-comb plate interface; determining whether the results of the scanning indicate that the object persists at the step-comb plate interface for a predetermined time; as well as The clamping is determined to be effective based on the result of the scanning indicating that the object is at the step-comb plate interface and lasts for the predetermined time.

19. The method of claim 18, further comprising determining escalator traffic by counting the total number of times an object persists at the step-comb plate interface for less than the predetermined time and the number of times an object persists at the step-comb plate interface for at least the predetermined time.

20. The method of claim 18, further comprising taking mitigating action to resolve the entrapment, the mitigating action comprising at least one or more of braking or slowing the escalator system, sounding an alarm, and adjusting the comb plate.

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