Elevator tension member elongation and stiffness monitoring system

Abstract

The invention discloses an elevator tension member elongation and stiffness monitoring system. A monitoring system is provided for an elevator system in which an elevator car and counterweight attached to a tension member travel in opposite directions through a hoistway. In one embodiment, a monitoring system includes a controller to travel an elevator car to a predefined location in a hoistway; a sensor for sensing a position of the counterweight when the elevator car is stopped at a predefined position and for generating data corresponding to the sensing result; and a processor operably coupled to the sensor and configured to analyze the data and configured to calculate an elongation of the tension member based on a result of the analysis.

Description

Background Art

[0001] The present disclosure relates to elevator systems, and in particular to an elevator tension member elongation and stiffness monitoring system.

[0002] In an elevator system, a hoistway is built into a building, and the elevator car travels up and down along the hoistway to reach the landing doors of different floors of the building. The elevator car is attached to the suspension belt at one of the suspension belts. The counterweight is attached to the other end of the lower suspension. The movement of the elevator car is driven by a machine, which is controlled by a controller according to instructions received from users of the elevator system. When those instructions command that the elevator car should move up through the hoistway, the machine rotates in one direction, so that the elevator car moves up and the counterweight moves down. Conversely, when the instructions command that the elevator car should move down through the hoistway, the machine rotates in the opposite direction, so that the elevator car moves down and the counterweight moves up. Summary of the invention

[0003] According to one aspect of the present disclosure, there is provided a monitoring system for an elevator system in which an elevator car and a counterweight attached to a tension member travel in opposite directions through a hoistway. The monitoring system comprises: a controller for causing the elevator car to travel to a predefined position in the hoistway; a sensor for sensing the position of the counterweight when the elevator car stops at the predefined position and for generating data corresponding to the sensed result; and a processor operably coupled to the sensor and configured to analyze the data and to calculate the elongation of the tension member based on the analysis result.

[0004] According to additional or alternative embodiments, the controller is configured to cause the elevator car to travel to a predefined position in response to an instruction to initiate the tension member monitoring control mode.

[0005] According to additional or alternative embodiments, the processor is further configured to estimate the tension member life based on the elongation.

[0006] According to additional or alternative embodiments, the processor is further configured to shut down the elevator system if the tension member life is less than a shutdown limit, and the processor is further configured to issue an alarm if the tension member life is less than an alarm limit but not less than a shutdown limit.

[0007] According to additional or alternative embodiments, at least one of the following items: the sensor is mounted on the elevator car and has a field of view (FOV) covering at least a portion of the counterweight when the elevator car is stopped at a predefined position; and the sensor is mounted remote from the elevator car and has a field of view (FOV) covering at least a portion of the counterweight when the elevator car is stopped at a predefined position.

[0008] According to an additional or alternative embodiment, the sensor is a LiDAR sensor.

[0009] According to additional or alternative embodiments, the sensor is a millimeter wave RADAR sensor.

[0010] According to an additional or alternative embodiment, the sensor is an RGBD camera.

[0011] According to additional or alternative embodiments, the sensor is one of a LiDAR sensor, a RADAR sensor or a camera.

[0012] According to one aspect of the present disclosure, there is provided a monitoring method for use in an elevator system in which an elevator car and a counterweight attached to a tension member travel in opposite directions through a hoistway. The monitoring method comprises: traveling the elevator car to a predefined position in the hoistway; sensing the position of the counterweight with the elevator car stopped at the predefined position; generating data corresponding to the sensed result; analyzing the data; and calculating the elongation of the tension member based on the analyzed result.

[0013] According to additional or alternative embodiments, the method further includes receiving an instruction to initiate a tension member monitoring control mode, and causing the elevator car to travel to a predefined position in response to receiving the instruction to initiate the tension member monitoring control mode.

[0014] According to additional or alternative embodiments, the method further comprises estimating the tension member life based on the elongation.

[0015] According to additional or alternative embodiments, the method further comprises shutting down the elevator system if the tension member life is less than a shutdown limit; and issuing an alarm if the tension member life is less than an alarm limit but not less than the shutdown limit.

[0016] According to additional or alternative embodiments, at least one of the following items: sensing is performed by a sensor, which is mounted on the elevator car and has a field of view (FOV) covering at least a portion of the counterweight when the elevator car is stopped at a predefined position; and sensing is performed by a sensor, which is mounted remote from the elevator car and has a field of view (FOV) covering at least a portion of the counterweight when the elevator car is stopped at a predefined position.

[0017] According to one aspect of the present disclosure, a monitoring method is provided for use in an elevator system in which an elevator car and a counterweight are attached to a tension belt around a pulley and travel in opposite directions through a hoistway. The monitoring method includes: recording a baseline weight of the elevator car; recording a baseline angular position of the pulley at a known position of the elevator car in the hoistway and with the baseline weight at an initial time, recording a current angular position of the pulley at a known position of the elevator car in the hoistway and with the baseline weight at a later time; and converting the difference between the baseline angular position and the current angular position into a stiffness measurement of the tension belt for use in determining the life of the tension belt.

[0018] According to additional or alternative embodiments, the stiffness measurement is directly proportional to the difference between the baseline angular position and the current angular position.

[0019] According to additional or alternative embodiments, the known location is a sensed location.

[0020] According to additional or alternative embodiments, the method further comprises: measuring a current weight of the elevator car; and recording at a later time a modified current angular position of the pulley at a known position of the elevator car in the hoistway and at the current weight; and the transforming comprises taking into account the difference between the baseline weight and the current weight in calculating the stiffness measurement result.

[0021] According to additional or alternative embodiments, the method further comprises using a characteristic sag-and-bounce change over time of the elevator car to confirm the stiffness measurement.

[0022] According to additional or alternative embodiments, the characteristic droop-and-bounce is established based on data generated at multiple instances of an elevator car becoming occupied.

[0023] According to one aspect of the present disclosure, a monitoring method for an elevator system is provided in which an elevator car and a counterweight are attached to a tension belt around a pulley and travel inversely through a hoistway. The monitoring method includes: recording a first data point at an initial time, the first data point including a first angular position and a second angular position of the pulley at a known position of the elevator car in the hoistway and at a first elevator car weight and a second elevator car weight, respectively; calculating an initial tension belt spring force based on the first data point; recording a second data point at a later time, the second data point including a first current angular position and a second current angular position of the pulley at a known position of the elevator car in the hoistway and at a first current elevator car weight and a second current elevator car weight, respectively; calculating a current tension belt spring force based on the second data point; and determining a tension belt life based on a difference between the initial tension belt spring force and the current tension belt spring force.

[0024] According to additional or alternative embodiments, calculating the initial tension band force based on the first data point includes calculating the ratio of the difference between the first elevator car weight and the second elevator car weight to the difference between the first angular position and the second angular position, and calculating the current tension band force based on the second data point includes calculating the ratio of the difference between the first current elevator car weight and the second current elevator car weight to the difference between the first current angular position and the second current angular position.

[0025] According to additional or alternative embodiments, the known location is a sensed location.

[0026] According to additional or alternative embodiments, the second elevator car weight is the sum of the first elevator car weight and the additional weight, and the second current elevator car weight is the sum of the first current elevator car weight and the additional weight.

[0027] According to additional or alternative embodiments, the additional weight includes at least one of a passenger weight and a load weight sensed by a load load cell.

[0028] According to additional or alternative embodiments, the additional weight is determined based on a change in motor torque.

[0029] 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 description and to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] 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:

[0031] Figure 1 is a perspective view of an elevator system according to an embodiment;

[0032] Figure 2 is a side view of an elevator car with a sensor according to an embodiment;

[0033] Figure 3 is a side view of an elevator car with a remote sensor according to an embodiment;

[0034] Figure 4 is a schematic diagram of a processor according to an embodiment;

[0035] Figure 5A and Figure 5B is a graphical diagram illustrating point cloud data generated by a sensor according to an embodiment;

[0036] Figure 6is a flow chart illustrating a monitoring method for use with an elevator system according to an embodiment;

[0037] Figure 7 is a graphical diagram illustrating the operation of a stiffness-based monitoring method according to an embodiment;

[0038] Figure 8 is a flow chart illustrating a stiffness-based monitoring method for use with an elevator system according to an embodiment;

[0039] Fig. 9 is a flow chart illustrating a monitoring method for use with an elevator system according to an embodiment; and

[0040] Fig.10 is a flow chart illustrating a monitoring method for use with an elevator system according to an embodiment. DETAILED DESCRIPTION

[0041] In the elevator industry, suspension components including coated steel strips (CSBs) need to be monitored for various properties, including but not limited to their residual load carrying capacity and stiffness. Elevator tension members in the form of CSBs can often use changes in resistance due to mechanical wear of their cords as a measure of remaining life for tension member life prediction. But some rope designs do not exhibit much wear, so a new non-resistance-based measure is needed. In addition, since ropes are significantly grounded as they interact with various metal components in the elevator system, resistance monitoring of ropes is not always a robust solution.

[0042] However, CSB test data has shown that suspension belt elongation tracks the suspension belt load carrying capacity and therefore can meet monitoring requirements. Several concepts have been proposed for this purpose and those concepts generally involve adding sensors and switches in the hoistway or on the counterweight (CWT), requiring time to install the devices and most importantly time and cost to install the required power and communication lines.

[0043] As will be described below, a sensor (such as a LiDAR sensor) is set on the elevator car or in the machine room of the elevator system to view the CWT when the elevator car is landed at a position in the hoistway. For example, a 2D LiDAR sensor can then scan across the hoistway to measure the location of the CWT. Changes in the relative position of the CWT (i.e., relative to the elevator car) can be used to monitor the elongation of the tension members over time. That is, as the tension members age and elongate, changes in the relative position of the CWT can be correlated to changes in the elongation of the tension members and used as a determining condition for the load carrying capacity of the tension members. Preliminary test data indicates that 0.1% elongation is a possible detection threshold, which is well within the resolution capabilities of low-cost 2D LiDAR sensors.

[0044] Additionally, as will be discussed below, a system and method for measuring suspension strap stiffness is provided. The system and method incorporates readings from various components of a processing system and an elevator system for determining tension member stiffness from those various readings.

[0045] refer to Figure 1 , which is a perspective view of an elevator system 101, which includes an elevator car 103, a counterweight 105, a tension member or tension members 107, guide rails 109, a machine 111, a position reference system 113, and a controller 115. The elevator car 103 and the counterweight 105 are interconnected by the tension member 107. The tension member 107 can include or be configured as, for example, a rope, a coated rope, a steel cable, and / or a coated steel belt. The counterweight 105 is configured to balance the load of the elevator car 103 and is configured to facilitate the movement of the elevator car 103 within the hoistway 117 and along the guide rails 109 relative to the counterweight 105 simultaneously and in opposite directions.

[0046] The tension member 107 engages a machine 111 that is part of the overhead structure of the elevator system 101. The machine 111 is configured to control movement between the elevator car 103 and the counterweight 105. The position reference system 113 can be mounted on a fixed portion at the top of the hoistway 117, such as on a support or rail, and can be configured to provide a position signal related to the position of the elevator car 103 within the hoistway 117. In other embodiments, the position reference system 113 can be mounted directly to the moving components of the machine 111, or can be located in other locations and / or configurations as known in the art. As known in the art, the position reference system 113 can be any device or mechanism for monitoring the position of the elevator car and / or counterweight. For example, but not limited to, the position reference system 113 can be an encoder, a sensor, or other system, and can include speed sensing, absolute position sensing, etc. (as will be appreciated by those skilled in the art).

[0047] As shown, the controller 115 can be located in a controller room 121 of the hoistway 117 and is configured to control the operation of the elevator system 101, and in particular the operation of the elevator car 103. It is to be appreciated that the controller 115 need not be in the controller room 121, but can be in other locations in the hoistway or elevator system. For example, the controller 115 can provide a drive signal to the machine 111 to control the acceleration, deceleration, leveling, stopping, etc. of the elevator car 103. The controller 115 can also be configured to receive a position signal from the position reference system 113 or any other desired position reference device. When moving up or down in the hoistway 117 along the guide rail 109, the elevator car 103 can stop at one or more landings 125 as controlled by the controller 115. Although shown in the controller room 121, those skilled in the art will appreciate that the controller 115 can be located and / or configured in other places or locations within the elevator system 101. In one embodiment, the controller 115 can be remotely located or located in a distributed computing network (e.g., a cloud computing architecture). The controller 115 may be implemented using a processor-based machine, such as a personal computer, a server, a distributed computing network, or the like.

[0048] The machine 111 may include a motor or similar drive mechanism. According to an embodiment of the present disclosure, the machine 111 is configured to include an electric drive motor. The power source for the motor may be any power source, including an electrical grid, which, in combination with other components, is supplied to the motor. The machine 111 may include a traction sheave that applies force to the tension member 107 to move the elevator car 103 within the hoistway 117.

[0049] The elevator system 101 also includes one or more elevator doors 104. The elevator doors 104 may be integrally attached to the elevator car 103, or the elevator doors 104 may be located on a landing 125 of the elevator system 101, or both. The embodiments disclosed herein may be applicable to elevator doors 104 integrally attached to the elevator car 103, or elevator doors 104 located on a landing 125 of the elevator system 101, or both. The elevator doors 104 open to allow passengers to enter and exit the elevator car 103.

[0050] Continue to refer Figure 1 And additional reference Figure 2 and Figure 3 as well as Figure 4 , provides an elevator system (such as Figure 1The monitoring system 201 includes a controller (such as the controller 115) configured to control the machine 111 to cause the elevator car 103 to travel to a predefined position in the hoistway 117 (i.e., the landing 125 or the intermediate hatch position). In this case, the controller 115 can be configured to cause the elevator car 103 to travel to the predefined position in response to the instruction for initiating the tension member monitoring control mode being received by the controller 115. The monitoring system 201 also includes: a sensor 210 (see Figure 2 ), sensor 310 (see Figure 3 ), to sense the position of the counterweight 105 when the elevator car 103 stops at a predefined position and to generate data corresponding to the sensed result; and a processor 401. The processor 401 is operably coupled to the sensors 210, 310, and is configured to analyze the data and is configured to calculate the elongation of the tension member 107 based on the analysis result. The processor 401 may also be configured to estimate the tension member life based on the elongation of the tension member 107. In addition, the processor 401 may also be configured to shut down the elevator system 101 if it is determined that the tension member life is less than the shutdown limit. Alternatively, the processor 401 may also be configured to issue an alarm if the tension member life is less than the alarm limit but not less than the shutdown limit.

[0051] like Figure 2 , the sensor 210 can be mounted on the elevator car 103 in such a manner that the field of view (FOV) of the sensor 210 covers at least a portion of the counterweight 105 when the elevator car 103 stops at a predefined position. For example, the sensor 210 can be mounted to the ceiling of the elevator car 103 and pointed downwardly toward the counterweight 105 when the elevator car 103 stops at a landing and the counterweight 105 is deployed to partially overlap the elevator car 103 in the height dimension.

[0052] Alternatively, Figure 3 , the sensor 310 can be mounted away from the elevator car 103 in such a way that the FOV of the sensor 310 covers at least a portion of the counterweight 105 when the elevator car 103 stops at a predefined position. For example, in a situation where the elevator car 103 stops at an elevator pit and the counterweight 105 is near the ceiling of the hoistway 117, the sensor 310 can be mounted at or near the ceiling of the hoistway 117 and pointed downwardly at the counterweight 105.

[0053] like Figure 4 As shown in FIG. 1 , the processor 401 includes a processing unit, a memory, and an input / output (I / O) unit, through which the processor 401 communicates with the sensors 210, 310 and at least the controller 115 (see FIG. 1 ). Figure 1 ) communication. The memory has executable instructions stored thereon, which are readable and executable by the processing unit. When the processing unit reads and executes the executable instructions, the executable instructions cause the processor to operate as described herein. According to an embodiment, the executable instructions may include a machine learning algorithm that improves certain operations of the processing unit over time. The processor 401 may be remote from the sensor 210, 310 or locally. In the former case, the processor 401 may be operably coupled to the sensor 210, 310 via a wired connection or via a wireless connection. In the latter case, the processor 401 may be built into the sensor 210, 310, or provided as a component separate from the sensor 210, 310 and operably coupled to the sensor 210, 310 via a wired connection or via a wireless connection.

[0054] According to an embodiment, the sensor 210, 310 may include or be provided as one or more of the following devices: 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 further embodiments, the sensor 210, 310 may be provided as one or more of the following devices: a 2D LiDAR sensor, a millimeter wave RADAR sensor and / or a red, green, blue depth (RGBD) camera. According to still further embodiments, the sensor 210, 310 may be provided as a plurality of sensors, including a combination of one or more sensor types listed herein.

[0055] Continue to refer Figure 1-4 And additional reference Figure 5A and Figure 5B In the exemplary case where the sensor 210, 310 is a 2D LiDAR sensor, the sensor 210, 310 is configured to Figure 2 and Figure 3 In these or other cases, the sensor 210, 310 is configured to generate data as point cloud data 501 using a single scan for image processing, multiple scans for image processing, and / or multiple sequential or continuous scans for video processing, and the processor 401 is configured to analyze the point cloud data 501 and to determine whether the point cloud data 501 is indicative of the counterweight 105 as determined by Figure 5A The point cloud data 501 shows that in plane P, Figure 5B The point cloud data 501 indicates that at least a portion of is outside the plane P.

[0056] It will be appreciated that the elongation of the tension member 107 will cause a corresponding sag in the positioning of the counterweight 105. This sag will appear as Figure 2The change in the relative distance between the counterweight 105 and the elevator car 103 in the embodiment of Figure 3 The distance between the fixed element in the shaft 117 and the counterweight 105 in the shaft 117 is changed in the embodiment of Figure 5A The processor 401 can recognize that the counterweight 105 is at a certain position relative to the elevator car 103 or in the hoistway 117 and that the certain position is not evidence of elongation of the tension member 107, however, for Figure 5B Based on the point cloud data 501 , the processor 401 can recognize that the counterweight 105 is at a certain position relative to the elevator car 103 or in the hoistway 117 and that the certain position is evidence of elongation of the tension member 107 .

[0057] refer to Figure 6 , provides an elevator system (such as Figure 1 Elevator system 101) and / or Figure 2-5B Monitoring method 600 used by monitoring system 201. Figure 6 As shown in FIG. 6 , the monitoring method 600 includes: initially receiving an instruction for initiating a tension member monitoring control mode (601); in response to the instruction being received, causing the elevator car to travel to a predefined position in the hoistway (602); sensing the position of the counterweight when the elevator car stops at the predefined position (603); and generating data corresponding to the sensed result, analyzing the data, and calculating the elongation of the tension member based on the analyzed result (604). As described above, the sensing of 603 can be performed by a sensor (such as a 2D LiDAR sensor) installed on or away from the elevator car. The monitoring method 600 may also include estimating the life of the tension member based on the elongation (605) and shutting down the elevator system (606) when the life of the tension member is less than the shutdown limit or issuing an alarm (607) when the life of the tension member is less than the alarm limit but not less than the shutdown limit.

[0058] While the description provided above relates to using elongation as a way to determine belt life, the following description will relate to using belt stiffness for a similar purpose.

[0059] refer to Figure 1 and the accompanying text and additional references Figure 7 , illustrates the operation of a stiffness-based tension member health monitoring system. Figure 7As shown in , when the elevator car is at a landing and before it is unloaded, the initial drive pulley position and the initial elevator car position along with the drive parking torque can be recorded. After the elevator car is loaded but before take-off, the current drive pulley position and the current elevator car position can be recorded so that the change in length of the tension member can be measured and the effective stiffness of the tension member can be determined. When the elevator car takes off, the drive holding torque can be used to calculate the actual load weight of the elevator car, and this load weight can then be used to update the estimate of the tension member stiffness.

[0060] Thus, it can be seen that there are certain input functional elements (i.e., sensed states) required for a "stiffness-based" tension member health monitoring system. However, it should be noted that the use of motor torque to estimate changes in load state can also be accomplished through specialized sensors commonly used in elevator systems called "load weight" sensors. This sensed state can be obtained through one or more of the following: (a) platform load weighing using under-car load sensors to detect the load in the car, (b) tension member tension measurement instruments that sense their tension, such as through the three pronged strain gage approach we commonly use on CSB-equipped elevators, and / or (c) termination load cells installed at the end termination of a 2:1 tension member elevator system.

[0061] refer to Figure 8 , a method 800 for monitoring the health of tension members based on stiffness is provided for elevator systems (such as Figure 1 Elevator system 101) and Figure 7 The stiffness-based health monitoring system for tension members is used. Figure 8 As shown in FIG. 8 , the monitoring method 800 includes: calculating a calculated load weight of an elevator car (801); generating an estimated load weight of the elevator car based on at least the estimate of the stiffness of the tension member at a load estimator that receives an estimate of the stiffness of the tension member (802); and determining an estimate of the stiffness of the tension member based on a difference between the calculated load weight and the estimated load weight (803).

[0062] According to an embodiment, one enabling feature of the "stiffness-based" tension member life monitoring method 800 is that the change in load in the elevator while parked and before subsequent departure is measured (via direct sensors) or calculated (as shown in this specific embodiment using the change in tension member length based on the difference between the drive pulley position and the car position).

[0063] Depending on the embodiment, the calculation of the calculated load weight of 801 can be based on the parking and holding torque or based on the load weight sensor reading. In addition, the load estimator can accept an estimate of the stiffness of the tension member and one or more of the following items: the elevator car parking location, the elevator car position, and the pulley position, and in these or other cases, the load estimator generates an estimated load weight of the elevator car based on at least the estimate of the stiffness of the tension member and one or more of the following items: the elevator car parking location, the elevator car position, and the pulley position. Notably, Figure 8 The feedback loop in can be used as part of a learning algorithm to self-calibrate the rope stiffness estimator in a time-adjusting mode.

[0064] refer to Fig. 9 According to another embodiment, a monitoring method 900 is provided for an elevator system (such as Figure 1 Elevator system 101) and / or Figure 2-5B The monitoring system 201 is used. Fig. 9 , the monitoring method 900 includes: recording a baseline weight of an elevator car (block 901); recording a baseline angular position of a pulley at a known position of the elevator car in a hoistway and under the baseline weight at an initial time (block 902); recording a current angular position of the pulley at a known position of the elevator car in the hoistway and under the baseline weight at a later time (block 903); and converting the difference between the baseline angular position and the current angular position into a stiffness measurement of the tension belt for use in determining the tension belt life (block 904). The known position of the elevator car can be the sensed position and can be provided by any of the sensors described above. Thus, the stiffness measurement can be directly proportional to the difference between the baseline angular position and the current angular position (i.e., where the difference between the baseline angular position and the current angular position is a percentage of the total angular rotation of the pulley required to move the elevator car from an initial location in the hoistway to the known position).

[0065] According to further embodiments, method 900 may be modified for situations in which the weight of the known elevator car changes over time. In these or other situations, method 900 may include measuring the current weight of the elevator car (block 905), and recording at a later time the modified current angular position of the pulley at the known position of the elevator car in the hoistway and at the current weight (block 906). Here, the transformation of block 904 may include accounting for the difference between the baseline weight and the current weight in calculating the stiffness measurement (block 9041). In addition, the method may include confirming the stiffness measurement using the change in the characteristic sag-and-bounce of the elevator car over time (block 907), which may be established based on data generated at multiple instances of the elevator car becoming occupied (i.e., by a person of known weight or by an unknown weight that must be determined and considered in determining the characteristic sag-and-bounce of the elevator car).

[0066] refer to Fig.10 According to another embodiment, a monitoring method 1000 is provided for an elevator system (such as Figure 1 Elevator system 101) and / or Figure 2-5B The monitoring system 201 is used. Fig.10 As shown in FIG. 1 , the monitoring method 1000 includes: recording a first data point at an initial time, which includes a first angular position and a second angular position of a pulley at a known position of an elevator car in a shaft (i.e., a sensed position) and at a first elevator car weight and a second elevator car weight, respectively (box 1001); calculating an initial tension band force based on the first data point (box 1002); recording a second data point at a later time, which includes a first current angular position and a second current angular position of the pulley at a known position of the elevator car in the shaft and at a first current elevator car weight and a second current elevator car weight, respectively (box 1003); calculating a current tension band force based on the second data point (box 1004); and determining a tension band life based on a difference between the initial tension band force and the current tension band force (box 1005).

[0067] According to further embodiments, the calculating of the initial tension band force according to the first data point of block 1002 includes calculating the ratio of the difference between the first elevator car weight and the second elevator car weight to the difference between the first angular position and the second angular position (block 10021), and the calculating of the current tension band force according to the second data point of block 1004 includes calculating the ratio of the difference between the first current elevator car weight and the second current elevator car weight to the difference between the first current angular position and the second current angular position (block 10041). In addition, the second elevator car weight may be the sum of the first elevator car weight and the additional weight, and the second current elevator car weight may be the sum of the first current elevator car weight and the additional weight. The additional weight may include at least one of the passenger weight and the load weight sensed by the load load cell, or the additional weight may be determined based on the change in motor torque when the weight is brought on and off the elevator car.

[0068] The technical effect and benefit of the present disclosure is to provide a low-cost sensor (such as a 2D LiDAR sensor) on the elevator car or another part of the hoistway, and does not require any additional markers or switches in the hoistway or powered sensors on the CWT itself. The relatively low resolution requirement for 0.1% belt elongation is well within the capabilities of LiDAR sensing. Therefore, the present disclosure provides a monitoring solution that reduces complexity and cost.

[0069] An additional technical effect and benefit of the present disclosure is to provide a system and method for measuring tension member stiffness using readings from various elevator system components. This allows belt stiffness to be determined using components already present in the elevator system and therefore presents a cost effective solution.

[0070] It will be appreciated that the use of elongation and stiffness to monitor belt health as described herein may be used alone or (in some cases) in combination to provide a robust estimate of tension belt life.

[0071] The corresponding structures, materials, actions and equivalents of all parts or steps plus functional elements in the claims below 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 is not intended to be exhaustive or limited to the technical concepts of the disclosed form. Without departing from the scope and spirit of the present disclosure, many modifications and variations will be apparent to those skilled in the art. The embodiments are selected and described 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 as suitable for the specific use contemplated.

[0072] Although preferred embodiments of the present disclosure have been described, it will be appreciated that those skilled in the art (present or future) may make various improvements and enhancements that fall within the scope of the appended claims. These claims should be construed to maintain the proper protection for the present disclosure first described.

Claims

1. A monitoring system for an elevator system in which an elevator car and a counterweight attached to a tension member travel in opposite directions through a hoistway, the monitoring system comprising: a controller for causing the elevator car to travel to a predefined position in the hoistway; a sensor for sensing a position of the counterweight when the elevator car stops at the predefined position and for generating data corresponding to a result of the sensing; as well as A processor is operably coupled to the sensor and is configured to analyze the data and to calculate an elongation of the tension member based on the analysis results.

2. The monitoring system according to claim 1, wherein: The controller is configured to cause the elevator car to travel to the predefined position in response to an instruction to initiate a tension member monitoring control mode.

3. The monitoring system according to claim 1, wherein: The processor is further configured to estimate a tension member life based on the elongation.

4. The monitoring system according to claim 3, wherein: The processor is further configured to shut down the elevator system if the tension member life is less than a shutdown limit, and The processor is further configured to issue an alarm if the tension member life is less than an alarm limit but not less than the shutdown limit.

5. The monitoring system according to claim 1, wherein: At least one of the following: The sensor is mounted on the elevator car and has a field of view (FOV) covering at least a portion of the counterweight when the elevator car is stopped at the predefined position, and The sensor is mounted remote from the elevator car and has a field of view (FOV) covering at least a portion of the counterweight when the elevator car is stopped at the predefined position.

6. The monitoring system according to claim 1, wherein: The sensor is a LiDAR sensor.

7. The monitoring system according to claim 1, wherein: The sensor is a millimeter wave RADAR sensor.

8. The monitoring system according to claim 1, wherein: The sensor is an RGBD camera.

9. The monitoring system according to claim 1, wherein: The sensor is one of a LiDAR sensor, a RADAR sensor or a camera.

10. A monitoring method for use in an elevator system in which an elevator car and a counterweight attached to a tension member travel in opposite directions through a hoistway, the monitoring method comprising: causing the elevator car to travel to a predefined position in the hoistway; sensing a position of the counterweight with the elevator car stopped at the predefined position; generating data corresponding to the sensing result; analyzing the data; as well as The elongation of the tension member is calculated based on the results of the analysis.

11. The method of claim 10, further comprising receiving an instruction for initiating a tension member monitoring control mode, in, Said causing the elevator car to travel to the predefined position is responsive to said receiving the instruction to initiate the tension member monitoring control mode.

12. The method of claim 10, further comprising estimating a tension member life based on the elongation.

13. The method according to claim 12, further comprising: shutting down the elevator system when the life of the tension member is less than a shutdown limit; as well as An alarm is issued in the event that the tension member life is less than an alarm limit but not less than the shutdown limit.

14. The method according to claim 10, wherein: At least one of the following: The sensing is performed by a sensor mounted on the elevator car having a field of view (FOV) covering at least a portion of the counterweight when the elevator car is stopped at the predefined position, and The sensing is performed by a sensor mounted remote from the elevator car having a field of view (FOV) covering at least a portion of the counterweight in case the elevator car is stopped at the predefined position.

15. A monitoring method for an elevator system in which an elevator car and a counterweight are attached to a tension belt around a pulley and travel in opposition through a hoistway, the monitoring method comprising: recording a first data point at an initial time, the first data point comprising a first angular position and a second angular position of the pulley at a known position of the elevator car in the hoistway and at a first elevator car weight and a second elevator car weight, respectively; Calculate the initial tension band elastic force according to the first data point; recording a second data point at a later time, the second data point comprising a first current angular position and a second current angular position of the pulley at the known position of the elevator car in the hoistway and at a first current elevator car weight and a second current elevator car weight, respectively; Calculate the current tension band elastic force according to the second data point; as well as The tension band life is determined based on the difference between the initial tension band force and the current tension band force.

16. The monitoring method according to claim 15, wherein: Calculating the initial tension band force based on the first data point includes calculating a ratio of a difference between the first elevator car weight and the second elevator car weight to a difference between the first angular position and the second angular position, and Calculating the current tension band force based on the second data point includes calculating a ratio of a difference between the first current elevator car weight and the second current elevator car weight to a difference between the first current angular position and the second current angular position.

17. The monitoring method according to claim 15, wherein: The known position is a sensed position.

18. The monitoring method according to claim 15, wherein: The second elevator car weight is the sum of the first elevator car weight and an additional weight; and The second current elevator car weight is the sum of the first current elevator car weight and an additional weight.

19. The monitoring method according to claim 18, wherein: The additional weight includes at least one of a passenger weight and a load weight sensed by a load load cell.

20. The monitoring method according to claim 18, wherein: The additional weight is determined based on a change in motor torque.

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