Method for monitoring characteristics of a door motion procedure of an elevator door using a smart mobile device

Abstract

A method and a device for monitoring characteristics of an elevator door motion procedure use a smart mobile device including multiple sensors. The method includes: (i) determining a time window, within which a door motion is assumed to occur, including a time interval enclosed by a start time limit and an end time limit and wherein at least one of the start time limit and the end time limit is determined based on first measurement values acquired by a first sensor in the smart mobile device; and (ii) detecting characteristics of the procedure based on second measurement values acquired during the time window by a second sensor in the smart mobile device. Using the method, door motion characteristics can be reliably monitored using a passenger's smart mobile phone while substantially limiting sensing and processing capacities required by the smart mobile phone as well as avoiding compromising passenger privacy requirements.

Claims

1. A method for monitoring characteristics of a door motion procedure of an elevator door using a smart mobile device including multiple sensors, the method comprising the steps of: determining a time window within which a door motion of the elevator door is assumed to occur including a start time limit and an end time limit enclosing a time interval of the time window and wherein at least one of the start time limit and the end time limit is determined based on first measurement values acquired by at least one first sensor of the multiple sensors of the smart mobile device; and detecting the characteristics of the door motion procedure of the elevator door based on second measurement values acquired during the time window by a second sensor of the multiple sensors of the smart mobile device.

2. The method according to claim 1 further comprising: wherein the door motion procedure includes a first door motion of a closing of the elevator door and a second door motion of a subsequent re-opening of the elevator door; wherein a start time limit of the first door motion and an end time limit of the second door motion form outer time extent limits and an end time limit of the first door motion and a start time limit of the second door motion form inner extent time limits; wherein the at least one first sensor includes a first type first sensor and a second type first sensor; determining the outer extent time limits based on the first measurement values acquired by the first type first sensor; and determining the inner extent time limits on the first measurement values acquired by the second type first sensor.

3. The method according to claim 1 including filtering the first measurement values acquired by the at least one first sensor and looking for characteristic signatures typical of a trip of an elevator car in the first measurement values.

4. The method according to claim 1 wherein each of the at least one first sensor and the second sensor is a sensor other than a camera and a microphone.

5. The method according to claim 1 wherein the at least one first sensor is one of a beacon signal receiver sensor, a light sensor, an acceleration sensor, a gyroscope sensor and a barometer sensor.

6. The method according to claim 1 wherein the second sensor is a magnetometer sensor.

7. The method according to claim 1 wherein the at least one first sensor is a beacon signal receiver sensor and wherein at least one of the start time limit and the end time limit of the time interval is determined based on detecting a beacon signal obtained by the beacon signal receiver sensor.

8. The method according to claim 1 wherein the at least one first sensor is a light sensor and wherein at least one of the start time limit and the end time limit of the time interval is determined based on detecting a change in a light sensor signal obtained by the light sensor, the change in the light sensor signal exceeding one of a predetermined threshold light intensity variation value and a predetermined threshold light intensity variation rate value.

9. The method according to claim 1 wherein the at least one first sensor is an acceleration sensor and wherein at least one of the start time limit and the end time limit of the time interval is determined based on detecting a predetermined profile in an acceleration sensor signal obtained by the acceleration sensor.

10. The method according to claim 1 wherein the at least one first sensor is a gyroscope sensor and wherein at least one of the start time limit and the end time limit of the time interval is determined based on detecting a predetermined profile in a gyroscopic signal obtained by the gyroscope sensor.

11. The method according to claim 1 wherein the at least one first sensor is a barometer sensor and wherein at least one of the start time limit and the end time limit of the time interval is determined based on detecting a change in a barometer pressure signal obtained by the barometer sensor, the change in the barometer pressure signal exceeding one of a predetermined threshold barometer pressure variation value and a predetermined threshold barometer pressure variation rate value.

12. The method according to claim 1 wherein the second sensor is a magnetometer sensor and wherein the characteristics of the door motion procedure are determined based on detecting a predetermined profile in a magnetometer sensor signal obtained by the magnetometer sensor.

13. The method according to claim 1 wherein at least one of the start time limit and the end time limit is determined based on various types of the first measurement values acquired by various types of the first sensors of the multiple sensors of the smart mobile device.

14. A device including a smart mobile device having multiple sensors and being adapted to at least one of execute and control the method according to claim 1.

15. A device including a smart mobile device and a remote monitoring device in communication and being adapted to execute and control the method according to claim 1.

16. The device according to claim 15 wherein the smart mobile device includes an interface for transmitting data or signals to the remote monitoring device.

17. A computer program product comprising non-transitory computer readable instructions which, when the instructions are performed by a processor, instruct the processor to perform the method according to claim 1.

18. A non-transitory computer readable medium comprising the computer program product according to claim 17 stored thereon.

Description

DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a device and its environment in an elevator for executing a monitoring method according to an embodiment of the present invention.

(2) FIG. 2 shows time-dependent sensor signals analyzed in a monitoring method according to an embodiment of the present invention.

(3) FIG. 3 shows a definition of a narrowest time window during a monitoring method according to an embodiment of the present invention.

(4) The figures are only schematic and not to scale. Same reference signs refer to same or similar features.

DETAILED DESCRIPTION

(5) FIG. 1 shows an elevator 1 comprising an elevator car 3 to be displaced vertically along an elevator shaft 5. The elevator car 3 comprises an elevator door 7. The elevator door 7 may be opened and closed in door motion procedures such as to free or block, respectively, an access to the elevator car 3. Upon the elevator door 7 being opened, a passenger 9 may enter the elevator car 3. Subsequently, the elevator door 7 may be closed and the elevator car 3 may be displaced towards another floor.

(6) The passenger 9 may carry a smart mobile device 11 such as a smart phone. The smart mobile device 11 comprises a multiplicity of sensors 13. The sensors 13 include multiple first sensors 29 and at least one second sensor 31. The first sensors 29 may include various different types of sensors 13 such as a beacon signal receiver sensor 45, a light sensor 47, an acceleration sensor 49, a gyroscope sensor 51 and a barometer sensor 53. The second sensor 31 may be a magnetometer sensor 55. Furthermore, the smart mobile device 11 comprises a processor 15 for processing sensor signals from the sensors 13. Additionally, the smart mobile device 11 comprises a memory 17 for storing data derived from the sensor signals. Finally, the smart mobile device 11 comprises an interface 19 for transmitting data or signals from the smart mobile device 11 to a remote monitoring device 21.

(7) A problem which may be solved with the monitoring method described herein is to use a smart mobile device 11 such as the passenger's smart mobile phone, this smart mobile device 11 serving as a sensor box, wherein the smart mobile device 11 is used for detecting and/or monitoring characteristics of a door motion procedure of the elevator door 7 by non-permanently, opportunistically activating the sensor box. Therein, the smart mobile device 11 may use several of its sensors 13 for providing sensor signals based on which the characteristics of the door motion procedure may be derived. However, it is preferable to not use sensor signals provided by a camera or by a microphone of the smart mobile device 11 as analyzing signal data from such sensors may pose privacy concerns. Other sensors 13 such as an IMU (inertial measurement unit) including the acceleration sensor 49 or alternative sensors 13 such as the light sensor 47, the gyroscope sensor 51, the barometer sensor 53 or the beacon signal receiver sensor 45 do not elicit strong privacy concerns. However, signal variety from different orientations and/or placements of the passenger's smart mobile device 11 may have to be overcome, as the smart mobile device 11 may be for example held in the passenger's hand while reading information from its display, may be stored in a pocket or inside a purse, etc.

(8) In order to solve the mentioned problem, a two-step approach is suggested. Details of such approach will now be explained with reference to FIGS. 2 and 3. Therein, FIG. 2 shows an exemplary time-line along two subsequent elevator car trips of several sensor signals such as the acceleration sensor signal 59, the light sensor signal 61 and the magnetometer sensor signal 63. Each elevator trip begins with a first door motion 41 of closing the elevator door 7 and ends with a second door motion 43 of opening the elevator door 7. The various sensor signals provided by first sensors 29 including e.g. the beacon signal receiver sensor 45, the light sensor 47, the acceleration sensor 49, the gyroscope sensor 51 or the barometer sensor 53 form first measurement values 37. The sensor signals provided by the second sensor 31 including the magnetometer sensor 55 form second measurement values 39. FIG. 3 visualizes a process of determining a narrowest time window 23 based on various sensor signals.

(9) In a first step of the suggested two-step approach, the time window 23 in which a door motion is assumed to occur is defined. Such defining of the time window 23 generally includes defining of a start time limit 25 and an end time limit 27 which enclose a time interval 26 of the time window 23. The start time limit 25 and the end time limit 27 are both determined based on first measurement values 37 acquired by one or more first sensors 29 of the smart mobile device 11.

(10) In a second step, characteristics of the door motion procedure are then detected based on second measurements 39 acquired by the second sensor 31 of the smart mobile device 11, those second measurements 39 being acquired mainly or exclusively within the previously defined time window 23.

(11) Assumptions underlying embodiments of the present invention are that it is possible to tie sensor data to the elevator installation that induced the data, e.g. via a Bluetooth beacon, Android Fused Location Provider using Wi-Fi, cell triangulation, GPS or similar localization data sources. Furthermore, offline processing of data should be possible, i.e. streaming data may be uploaded to a centralized server and/or analyzed periodically in batches.

(12) In possible embodiments, the proposed monitoring method may include a filtering step, a segmentation step and a step of detecting door motion procedures. A goal is to generate narrowest possible extents in time, which is referred to herein as the “time window” 23, in which a door motion procedure could lie within a data stream. Specifically, the monitoring method may include, first, a trip filtering, then a segmentation of door motion procedures or events and, finally, a door motion procedure recognition.

(13) In more detail, the monitoring method may begin with the step of trip filtering. As sensors 13 in a smart mobile device 11 may be recorded at any time without being near an elevator 1, it may be looked for characteristic acceleration and/or deceleration signatures which are unique to forces experienced by the smart mobile device 11 upon taking the elevator 1. For example, an L2-norm of 3-axis acceleration signals provided by an accelerations sensor 49 may be approximated by two Gaussian curves. A goodness of a fit could filter signals for further processing. A “fingerprint” of an acceleration typically occurring upon accelerating and/or decelerating the elevator car 3 at the beginning and/or the end of an elevator trip, respectively, may be represented by a predetermined typical profile 57 in the acceleration sensor signal 59 (see FIG. 2).

(14) Subsequently, in the segmentation step, door motion procedures are to be detected. In other words, the goal of the segmentation phase is to determine time segments in which door motion events may lie. For such purpose, as exemplarily visualized in FIG. 3, start time limits 25 and end time limits 27, or, in an alternative interpretation, outer time extent limits 33 and inner time extent limits 35, may be determined for each elevator car trip based on various first measurement signals 37a, 37b, 37c obtained from different types of first sensors 29.

(15) For example, beacon signal emitters may be provided at or close to elevator doors 7. Accordingly, a beacon signal receiver sensor 45 comprised in the smart mobile device 11 may detect a presence or absence of an emitted beacon signal when coming into a proximity of a beacon signal emitter. As the presence of the beacon signal is typically detected just before the elevator door 7 closes and the absence of the beacon signal is detected after the elevator door 7 opened again, this information may be used as first measurement values 37a for setting outer time extent limits 33, i.e. for setting a start time limit 25 before the closing door motion procedure and an end time limit 27 after the re-opening door motion procedure.

(16) In some cases, significant changes in light intensity as sensed by the light sensor 47 and represented by first measurement values 37c may indicate that a passenger with his smart mobile device 11 has entered in or exited from the elevator car 3. Similar to the presence or absence of the first measurement signal 37a of the beacon signal, first measurement values 37c relating to significant light changes may be taken for setting outer time extent limits 33 for segmenting signals in order to narrow the time window 23, i.e. in order to shorten the time interval 26, thereby narrowing the search for door motion procedures.

(17) Furthermore, due to e.g. a turning movement of the passenger 9 after having entered the elevator car 3 in order to face the elevator door 7 once inside the elevator car 3, a characteristic peak may occur in a gyroscopic signal (not shown) provided by the gyroscope sensor 51. The peak may be characteristic in angle and/or angular velocity. Accordingly, such information may be taken for setting outer time extent limits 33 or for verifying outer time extent limits 33 which were set based on other sensor signals.

(18) If a barometer sensor 53 is available, a segment in which there is a non-zero first derivative in ambient pressure may be taken for setting inner time extent limits 35. In other words, a vertical displacement of the elevator car 3 is generally started just after the elevator door 7 has closed and ends just before the elevator door 7 opens again. As, during such vertical displacement, the ambient air pressure significantly changes, the measured barometer pressure variation (not shown) may be compared with a predetermined threshold barometer pressure variation value and/or the measured barometer pressure variation rate may be compared with a predetermined barometer pressure variation rate value in order to define the inner time extent limits 35.

(19) As a further measure, first measurement values 37b corresponding to the acceleration sensor signal 59 from the acceleration sensor 49 may be used for setting the inner time extent limits 35. As elevator car deceleration generally precedes an elevator door opening motion and elevator car acceleration generally follows an elevator door closing motion, typical profiles in an acceleration sensor signal 59 may indicate corresponding start time limits 25 and end time limits 27.

(20) Additionally, if available, activity recognition hardware onboard of modern smart mobile devices 11 may provide direct outputs such as “standing”, “sitting” or “walking”. For example, “standing” detection may be used directly as candidate segments.

(21) Given the set of outer and inner time extent limits 33, 35 and/or corresponding start and end time limits 25, 27, the time window 23 defined by the enclosed time interval 26 may be set to the narrowest possible extent in which a door motion procedure is assumed to occur.

(22) Finally, the door motion recognition may be implemented based on second measurement values 39 based on magnetometer sensor signals 63 obtained from the magnetometer sensor 55. Having segmented the narrowest possible time window 23 in which a door motion procedure lies, characteristic patterns or profiles in the magnetometer sensor signals 63 may be used to recognize and measure for example a duration of a door motion procedure. For example, peak shapes in a norm of the magnetometer sensor signals 63 may characterize the movement of a metallic elevator door 7 being positioned near the smart mobile device 11.

(23) It is possible that single second measurement values 39 obtained by the smart mobile device 11 do not detect elevator door procedures correctly, for example due to the passenger 9 with his mobile device 11 standing at the back of the elevator car 3 where the magnetometer sensor 55 may not reliably sense magnetic field changes caused by an elevator door motion. However, upon receiving repeated second measurements 39 of the same equipment from many passengers' smart mobile devices 11, door motion procedures may be opportunistically spotted. Accordingly, a likelihood of successful door motion procedure detection may increase with increased usage of the method.

(24) Overall, embodiments of the method presented herein provide a clearly-defined approach to tackle specific issues of door motion procedures from crowd-generated data. Need for hardware, connectivity and/or maintenance may be eliminated to a great degree. Furthermore, an objective third party installation insight and usage patterns may be provided.

(25) Finally, it should be noted that the term “comprising” does not exclude other elements or steps and the “a” or “an” does not exclude a plurality. Also, elements described in association with different embodiments may be combined.

(26) In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope.