Method for preventive maintenance of an elevator and an elevator system
11753275 · 2023-09-12
Assignee
Inventors
- Matti MUSTONEN (Helsinki, FI)
- Arttu Leppäkoski (Helsinki, FI)
- Ari Jussila (Helsinki, FI)
- Juha-Matti Aitamurto (Helsinki, FI)
Cpc classification
B66B5/0087
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A method for preventive maintenance of an elevator speed sensor system includes at least a first and a second sensor, which are independent of each other. The method includes: determining a reference distance for an elevator car travel between a first door zone and a second door zone, during the elevator car travel, defining continuously a first elevator car speed information from the first sensor and a second elevator car speed information from the second sensor, calculating a cumulative sensor system error by integrating the difference between the first elevator car speed information and the second elevator car speed information, and dividing the cumulative sensor system error with the reference distance to obtain a sensor system performance indicator.
Claims
1. A method for preventive maintenance of an elevator speed sensor system comprising at least a first and a second sensor, which are independent of each other, the method comprising: determining a reference distance for an elevator car travel between a first door zone and a second door zone; during an elevator car travel between the first door zone and the second door zone, defining continuously first elevator car speed information from the first sensor and second elevator car speed information from the second sensor; calculating a cumulative sensor system error by integrating a difference between the first elevator car speed information and the second elevator car speed information; and dividing the cumulative sensor system error with the reference distance to obtain a sensor system performance indicator.
2. The method according to claim 1, comprising: obtaining supply frequency of an elevator hoisting motor during the elevator car travel continuously from a motor controller of a hoisting machine of the elevator car and defining third elevator car speed information therefrom; comparing the first elevator car speed information and the second elevator car speed information with the third elevator car speed information; and based on the comparison, adding a sensor identification to the sensor system performance indicator.
3. The method according to claim 1, comprising: transmitting the sensor system performance indicator to a maintenance server; in the maintenance server, establishing a service request based on a sensor system performance indicator or on a sequence of sensor system performance indicators, the service request being established before the speed sensor system is considered as defective; and transmitting the service request to a maintenance service unit.
4. The method according to claim 1, comprising: calculating statistics information from a set of performance indicators; transmitting the statistics information to a maintenance server; in the maintenance server, establishing a service request based on the statistics information, the service request being established before the speed sensor system is considered as defective; and transmitting the service request to a maintenance service unit.
5. The method according to claim 1, wherein the first sensor is a first pulse sensor unit providing pulse position information of a traction sheave of a hoisting machine of the elevator car, the first pulse sensor unit comprising: at least one magnetic sensor measuring magnetic field variation from a rotating magnet ring arranged in the traction sheave of the hoisting machine.
6. The method according to claim 1, wherein the second sensor is a pulse sensor unit providing pulse position information of the elevator car, the pulse sensor unit comprising: at least one quadrature sensor measuring incremental pulses from a rotating magnet ring arranged in an overspeed governor arranged in an elevator shaft.
7. The method according to claim 1, wherein a floor number, identification code, magnet type, and a linear position of the elevator car within a door zone of the first and second door zones is obtained from at least one door zone sensor unit comprising at least one Hall sensor or a RFID reader.
8. The method according to claim 7, wherein calculating a reference distance for an elevator car travel between a first door zone and a second door zone comprises: obtaining and storing a pre-information about at least one door zone magnet at a door zone of each floor of an elevator shaft during a setup run, the pre-information comprising the following: floor number, identification code, magnet type, pulse position information, linear position information; and calculating the reference distance between the door zones by using the pre-information.
9. An elevator system comprising: an elevator car; a hoisting machine with a hoisting motor to drive the elevator car; a speed sensor system comprising at least a first sensor and a second sensor for measuring movement of the elevator car; and an elevator control apparatus, wherein the elevator control apparatus is connected to the first sensor and the second sensor, wherein the elevator control apparatus has a remote connection interface to a maintenance server, and wherein the elevator control apparatus is configured to perform the method according to claim 1 for preventive maintenance of the elevator system.
10. The method according to claim 2, comprising: transmitting the sensor system performance indicator to a maintenance server; in the maintenance server, establishing a service request based on a sensor system performance indicator or on a sequence of sensor system performance indicators, the service request being established before the speed sensor system is considered as defective; and transmitting the service request to a maintenance service unit.
11. The method according to claim 2, comprising: calculating statistics information from a set of performance indicators; transmitting the statistics information to a maintenance server; in the maintenance server, establishing a service request based on the statistics information, the service request being established before the speed sensor system is considered as defective; and transmitting the service request to a maintenance service unit.
12. The method according to claim 3, comprising: calculating statistics information from a set of performance indicators; transmitting the statistics information to a maintenance server; in the maintenance server, establishing a service request based on the statistics information, the service request being established before the speed sensor system is considered as defective; and transmitting the service request to a maintenance service unit.
13. The method according to claim 2, wherein the first sensor is a first pulse sensor unit providing pulse position information of a traction sheave of the hoisting machine of the elevator car, the first pulse sensor unit comprising: at least one magnetic sensor measuring magnetic field variation from a rotating magnet ring arranged in the traction sheave of the hoisting machine.
14. The method according to claim 3, wherein the first sensor is a first pulse sensor unit providing pulse position information of a traction sheave of a hoisting machine of the elevator car, the first pulse sensor unit comprising: at least one magnetic sensor measuring magnetic field variation from a rotating magnet ring arranged in the traction sheave of the hoisting machine.
15. The method according to claim 4, wherein the first sensor is a first pulse sensor unit providing pulse position information of a traction sheave of a hoisting machine of the elevator car, the first pulse sensor unit comprising: at least one magnetic sensor measuring magnetic field variation from a rotating magnet ring arranged in the traction sheave of the hoisting machine.
16. The method according to claim 2, wherein the second sensor is a pulse sensor unit providing pulse position information of the elevator car, the pulse sensor unit comprising: at least one quadrature sensor measuring incremental pulses from a rotating magnet ring arranged in an overspeed governor arranged in a elevator shaft.
17. The method according to claim 3, wherein the second sensor is a pulse sensor unit providing pulse position information of the elevator car, the pulse sensor unit comprising: at least one quadrature sensor measuring incremental pulses from a rotating magnet ring arranged in an overspeed governor arranged in a elevator shaft.
18. The method according to claim 4, wherein the second sensor is a pulse sensor unit providing pulse position information of the elevator car, the pulse sensor unit comprising: at least one quadrature sensor measuring incremental pulses from a rotating magnet ring arranged in an overspeed governor arranged in a elevator shaft.
19. The method according to claim 5, wherein the second sensor is a second pulse sensor unit providing pulse position information of the elevator car, the second pulse sensor unit comprising: at least one quadrature sensor measuring incremental pulses from a rotating magnet ring arranged in an overspeed governor arranged in a elevator shaft.
20. The method according to claim 2, wherein a floor number, identification code, magnet type, and a linear position of the elevator car within a door zone of the first and second door zones is obtained from at least one door zone sensor unit comprising at least one Hall sensor or a RFID reader.
Description
BRIEF DESCRIPTION OF FIGURES
(1) The embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings.
(2)
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DESCRIPTION OF SOME EMBODIMENTS
(9)
(10) Furthermore, the elevator system 100 comprises at least one door zone magnet 114a-114n at a door zone of each floor of the elevator shaft. The at least one door zone magnet 114a-114n is fixed to the elevator shaft. Preferably, the at least one magnet 114a-114n may be fixed to a landing door frame in the elevator shaft. The door zone may be defined as a zone extending from a lower limit below floor level 116a-116n to an upper limit above the floor level 116a-116n in which the landing and car door equipment are in mesh and operable. The door zone may be determined to be from −400 mm to +400 mm for example. Preferably, the door zone may be from −150 mm to +150 mm. Alternatively or in addition, the elevator system 100 according to the invention may comprise at least one terminal magnet at least at one terminal floor of the elevator shaft. The at least one terminal floor may be the top or the bottom floor. Each magnet may comprise at least one passive RFID tag. The at least one RFID tag comprises unique identification code (UID) and type code of the magnet.
(11) Additionally, for safety reasons elevator system may comprise an overspeed governor (OSG) 112 arranged in the elevator shaft to stop the movement of the elevator car 102, if the elevator car 102 speed meets a predefined speed limit. The OSG 112 may comprise a sheave 113 rotated by a governor rope (not shown in
(12) A schematic example of the safety control unit 104 according to the invention is disclosed in
(13) The processor 402 of the safety control unit 104 is at least configured to implement at least some method steps as described. The implementation of the method may be achieved by arranging the at least one processor 402 to execute at least some portion of computer program code 405a-405n stored in the memory 404 causing the one processor 402, and thus the safety control unit 104, to implement one or more method steps as described. The processor 402 is thus arranged to access the memory 404 and retrieve and store any information therefrom and thereto. For sake of clarity, the processor 402 herein refers to any unit suitable for processing information and control the operation of the safety control unit 104, among other tasks. The operations may also be implemented with a microcontroller solution with embedded software. Similarly, the memory 404 is not limited to a certain type of memory only, but any memory type suitable for storing the described pieces of information may be applied in the context of the present invention.
(14) As described the pulse position information of the elevator car 102 may be obtained from the pulse sensor unit 108. A schematic example of the pulse sensor unit 108 according to the invention is disclosed in
(15) The processor 501 of the pulse sensor unit 108 is at least configured to obtain the quadrature signal from the at least one quadrature sensor, define the pulse position information based on the quadrature signals and to store the defined pulse position information into the memory 503. The processor 502 is thus arranged to access the memory 504 and retrieve and store any information therefrom and thereto. For sake of clarity, the processor 501 herein refers to any unit suitable for processing information and control the operation of the pulse sensor unit 108, among other tasks. The operations may also be implemented with a microcontroller solution with embedded software. Similarly, the memory 503 is not limited to a certain type of memory only, but any memory type suitable for storing the described pieces of information may be applied in the context of the present invention. The pulse sensor unit 108 may be a separate unit communicatively coupled to the safety control unit 104. Alternatively, the pulse sensor unit 108 may be implemented as part of the safety control unit 104 or the pulse sensor unit may be implemented as an additional circuit board operating as an interface between the at least one quadrature sensor 504 and the safety control unit 104.
(16) As described at least the linear position information of the elevator car 102 may be obtained from at least one door zone sensor unit 106. Preferably, one door zone sensor unit 106 may be provided for each elevator car door. A schematic example of the at least one door zone sensor unit 106 according to the invention is disclosed in
(17) The processor 602 of the door zone sensor unit 106 is at least configured to provide at least the following door zone information within the door zone of each floor: floor number, magnet type, identification code of the magnet, linear position of the elevator car, speed of the elevator car. The at least one Hall sensor 610 of the door zone sensor unit 106 is configured to obtain the strength of magnetic field as the elevator car 102 bypassing the at least one door zone magnet 114a-114n at the door zone. Based on the obtained magnetic field strength at least the linear position and the speed of the elevator car 102 within the door zone may be defined. For example, the speed of the elevator car 102 may be defined from a rate of change of the linear position of the elevator car 102 defined from the obtained strength of magnetic field as the elevator car 102 bypasses the at least one door zone magnet 114a-114n at the door zone. The number of Hall sensors 610 may be determined based on the number of the door zone magnets 114a-114n at the door zone of each floor 116a-116n. The RFID reader 612 of the door zone sensor unit 106 is configured to obtain at least the floor number, magnet type and identification code of the magnet from the RFID tag of the at least one door zone magnet 114a-114n. The door zone information may be obtained only within the door zone of each floor of the elevator shaft.
(18) The processor 602 is arranged to access the memory 604 and retrieve and store any information therefrom and thereto. For sake of clarity, the processor 602 herein refers to any unit suitable for processing information and control the operation of the door zone sensor unit 106, among other tasks. The operations may also be implemented with a microcontroller solution with embedded software. Similarly, the memory 604 is not limited to a certain type of memory only, but any memory type suitable for storing the described pieces of information may be applied in the context of the present invention.
(19) The absolute position information of the elevator car 102 may be defined substantially accurately by means of the method, safety control unit and elevator system as described above. Alternatively or in addition, the absolute position information of the elevator car 102 may be defined at two channels in order to certainly meet the SIL3 level accuracy requirements. In order to define two-channel absolute position information the pulse position information and door zone information may be obtained at two channels. The two-channel pulse position information may be obtained from of the pulse sensor unit 108 comprising one quadrature sensor and at least one processor at each channel. Furthermore, the two-channel door zone information may be obtained from the door zone sensor unit 106 comprising at least one Hall sensor and at least one processor at each channel. The above presented method safety control unit, and elevator system may be implemented for two channels similarly as described above for one channel.
(20) Turning to
(21) The first sensor is a pulse sensor unit 121 providing a pulse position information of the traction sheave of the hoisting machine 120 of the elevator car. The pulse sensor unit 121 comprises a magnetic sensor 122 measuring magnetic field variation from a rotating magnet ring 123 arranged in the traction sheave of the hoisting machine.
(22) The first sensor 121 and the second sensor 108 are independent of each other, which means that failure of one sensor does not directly affect the other sensor. Thus, a reciprocal comparison of sensor readings of the separate sensors 121, 108 may provide information about operating condition of the sensor(s) 121, 108.
(23) The elevator system 100 further comprises a drive unit 125, which is configured to supply electric power to the hoisting motor to drive elevator car 102. The elevator system 100 also has an elevator control unit 124, which is responsible of receiving car calls from elevator passengers and which also commands drive unit 124 such that elevator car can serve the generated car calls. Therefore elevator control unit 124 also monitors elevator car movement in elevator shaft. Accordingly, elevator control unit is connected to the pulse sensor units 108, 121.
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(25) Further, data received from the pulse sensor units 108, 121, it processed and memorized in the elevator control unit 124 for maintenance purposes. As pictured in
(26) As mentioned above, elevator control unit 124 receives pulse position information during elevator travel continuously from the pulse sensor units 108, 121. A reference distance xref for an elevator car travel between different door zones is calculated and memorized during setup run. The setup run is performed before the elevator car 102 may be taken into actual operation. During the setup run the elevator car 102 may be configured to drive first either at the top floor or at the bottom floor and then the elevator car 102 is configured to drive the elevator shaft from one end to the other end. The setup run may comprise obtaining and storing pre-information about the at least one door zone magnet 114a-114n at the door zone of each floor of the elevator shaft. The pre-information may be stored in a non-volatile memory of the safety control unit. The pre-information may comprise at least the following: floor number, identification code, magnet type, pulse position information, linear position information. The linear position information of the elevator car within the door zone, the floor number, identification code, and magnet type may be obtained from the door zone sensor unit 106 comprising at least one Hall sensor and RFID reader as will be described later. The pulse position information may be obtained from the pulse sensor unit 108 as will be described later. The pulse position information and linear position information may be obtained at mid-point of each door zone magnet.
(27) The reference distance xref is calculated from the pre-information as a distance between consecutive door zones in the shaft.
(28) During an elevator car travel between a first and a second selected door zones, a first elevator car speed information v1 is determined continuously from the pulse position information of the first pulse sensor unit 121 and a second elevator car speed information v2 is determined continuously from the pulse position information of the second pulse sensor unit 108. This may be done by measuring number of pulses in a certain time interval or by measuring time difference between consecutive pulses, for example.
(29) A cumulative sensor system error is calculated by integrating the difference between the first elevator car speed information v1 and the second elevator car speed information v2. This cumulative sensor system error is further divided with the reference distance xref to obtain a sensor system performance indicator Kp as a relative value, which is easier to process in the data analytics in the maintenance server 127. The sensor system performance indicator Kp calculation process may be represented with an equation as follows:
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(31) In first embodiment, the calculated sensor system performance indicators Kp are first memorized in the elevator control unit 124. In selected time intervals, e.g. once a day, the performance indicators Kp are transferred to the maintenance server 127. In the maintenance server, a sequence of consequent performance indicators is processed to identify e.g. growing trends which would give an indication of maintenance need of the pulse sensor system 108, 121. When maintenance need is determined, service request is established in the maintenance server 127, preferably already before the pulse sensor system is considered as defective. The service request scheduled and transmitted to a suitable maintenance unit (having required knowledge and a corresponding geographical location) such that maintenance can be done before the pulse sensor system fails.
(32) In a second embodiment, statistics information is calculated in the elevator control unit 124 from the sensor system performance indicators Kp before they are sent to the maintenance server 127. In the maintenance server, the statistics information is then used instead of (or in addition to) the separate performance indicators to determine maintenance need. This may be advantageous such that non-relevant variation between separate sensor system performance indicators Kp may be omitted.
(33) In some refinements, elevator control unit 124 also reads during elevator car travel continuously the supply frequency of the elevator hoisting motor of the hoisting machine 120 from the drive unit 125 and defines a third elevator car speed information therefrom. By comparing the first elevator car speed information v1 from the first pulse sensor unit 121 and the second elevator car speed information v2 from the second pulse sensor unit 108 with the third elevator car speed information, it is possible to define which sensor 108, 121 is defective and add this sensor identification information to the sensor system performance indicator Kp.
(34) The present invention as hereby described provides great advantages over the prior art solutions. For example, the present invention improves at least partly the safety of the elevators. The present invention enables implementation of diagnosis and preventive maintenance of an absolute positioning by using already existing door zone sensor unit, elevator control unit and safety control unit together with additional substantially inexpensive components, such as magnet ring in OSG, and a pulse sensor unit comprising at least one quadrature sensor. The total costs of the additional components may be substantially less than the total costs of the prior art solutions. Moreover, in the present invention the travelling height is not limited, because the absolute position information may be defined continuously regardless of the place of the elevator car in the elevator shaft without any expensive magnetic tape or similar extending from end to end of the elevator shaft. Furthermore, the present invention enables two-channel absolute positioning for SIL3 safety integrity level that may be required for many safety functions in an elevator system.
(35) The verb “meet” in context of an SIL3 level is used in this patent application to mean that a predefined condition is fulfilled. For example, the predefined condition may be that the SIL3 level accuracy limit is reached and/or exceeded.
(36) This invention is also useful for many different kind of elevators, such as counterweightless elevators, multicar elevators, high-rise elevators, elevators propelled with linear motors, et cetera.
(37) The specific examples provided in the description given above should not be construed as limiting the applicability and/or the interpretation of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.