System and a method for detecting an out-of-operation state of an elevator system

A system for detecting an out-of-operation state of an elevator system includes a monitoring unit and a sensor unit. The sensor unit is configured to: detect at least one event indicating a generation of an elevator call and provide a message indicating the generation of an elevator call to the monitoring unit. The monitoring unit is configured to: initiate a time measuring function in response to receiving the message from the sensor unit, monitor a response of the elevator system to the generated elevator call. A method for detecting an out-of-operation state of an elevator system is also disclosed.

TECHNICAL FIELD

The invention concerns in general the technical field of elevator systems. Especially the invention concerns monitoring of condition of elevator systems.

BACKGROUND

Elevator systems may go out-of-operation, e.g. a movement of an elevator car may be stopped, due to many different reasons, such as due to technical failure, vandalism, etc. To minimize the impact of the out-of-operation of the elevator system on the passengers, a service request needs to be generated as soon as possible in order to send a maintenance technician to the site to fix the elevator system. The detection whether the elevator system has gone out-of-operation or not may be done based on data collected from the elevator system. However, it may be difficult to make an accurate detection whether the elevator system has gone out-of-operation or not, e.g. whether the elevator car is truly stopped or not.

Typically, the condition of the elevator system may be monitored by monitoring fault status and/or operating status of the elevator system directly from an elevator controller, e.g. by reading fault codes. At least one drawback of this may be that the access to monitor the fault/operating status may not be available, e.g. in case of old elevator systems and/or for parties other than manufacturer of the elevator system. Furthermore, it may not be possible to infer availability of the elevator from fault codes at high enough coverage and accuracy over all possible failure situations.

Another typical way to monitor the condition of the elevator system may be monitoring one or more outputs of the elevator system, e.g. movements of the elevator car, movements of one or more doors of the elevator system, open/closed status of one or more doors of the elevator system, vibrations, safety circuit state, elevator car stopping behavior, position of the elevator car inside the elevator shaft, and/or noise, etc., by means of a retrofitted monitoring unit with one or more add-on sensors. However, when the data is collected by the monitoring unit retrofitted to the elevator system, the accuracy of the detection may be lower than when the data is obtained directly from the elevator controller.

Thus, the main drawback of monitoring method by means of the retrofitted monitoring unit with add-on sensor(s) is inaccuracy, because it may be challenging to infer with high accuracy whether the elevator system is out-of-operation or not, which may lead to false positive alerts (which may cause cost of maintenance visit without any problems) and/or false negative alerts, i.e. missing actual failure cases because everything seems normal but elevator is failed. Moreover, at least one drawback of monitoring the outputs of the elevator system is that it only allows detections of condition of the elevator system, when the elevator car is moving and the out-of-operation situations, when the elevator car is standing at a landing cannot be distinguished from the normal operation of the elevator system, because from the monitoring unit point of view the condition of the elevator system may look normal, but the elevator system may still be out-of-operation. Even up to three out of four out-of-operation situations may be such that the elevator car is standing at a landing.

Alternatively, the condition of the elevator system may be monitored by generating remote elevator calls to one or more elevator cars when an unconventional low-usage period is identified and by monitoring response of the elevator car to the remote elevator call. If a movement of the elevator car is not detected in response to the remote elevator call, it indicates that the elevator system may be out-of-operation. However, this causes unnecessary power consumption of the elevator system, movements of the elevator in response to the remote elevator call may irritate the passengers, and this may also cause safety issues since the elevator car may be moving unexpectedly. Moreover, the possibility to generate random remote elevator calls may pose information security issues, e.g. a malicious hacker may be able to generate a huge amount of usage on the elevator system.

Thus, there is need to develop further solutions in order to improve at least partly the reliability of monitoring of condition of an elevator system.

SUMMARY

An objective of the invention is to present a system and a method for detecting an out-of-operation state of an elevator system. Another objective of the invention is that the system and the method for detecting an out-of-operation state of an elevator system enables a simple way to identify out-of-operation state of the elevator system by monitoring elevator call giving attempts.

The objectives of the invention are reached by a system and a method as defined by the respective independent claims.

According to a first aspect, a system for detecting an out-of-operation state of an elevator system is provided, wherein the system comprises: a monitoring unit for monitoring one or more operations of the elevator system and a sensor unit arranged in a vicinity of a landing call device and configured to: detect at least one event indicating a generation of an elevator call and provide a message indicating the generation of an elevator call to the monitoring unit; and wherein the monitoring unit is configured to: initiate a time measuring function in response to receiving the message from the sensor unit, and monitor a response of the elevator system to the generated elevator call.

The monitoring unit may further be configured to generate at least one signal indicating an out-of-operation state of the elevator system to an external computing entity in response to a detection that the elevator system is not responding to the generated elevator call in an expected manner during a predefined delay time after initiating the time measuring function.

Alternatively, the monitoring unit may further be configured to provide the monitored response to the external computing entity, and the external computing entity may be configured to generate an indication that the elevator system is out-of-operation, in response to a detection that the elevator system is not responding to the generated elevator call in an expected manner during a predefined delay time after initiating the time measuring function.

The sensor unit may comprise a first sensor device for detecting a first event indicating the generation of an elevator call within a detection zone of the first sensor device, wherein the first event may be one of the following: motion of an object, gesture of an object, a change in a distance between the sensor unit and a nearest detected object.

The sensor unit may further comprise a second sensor device for detecting a second event within a detection zone of the second sensor device before detection of the first event by the first sensor device, wherein the second event may be a motion of an object or a gesture of an object.

Furthermore, the sensor unit may be configured to wake up from a sleep mode in response to a detection of the second event by the second sensor device and to initiate a monitoring mode of the first sensor device for a predefined monitoring period.

Moreover, if the first event is the change in a distance between the sensor unit and a nearest detected object, the message may further comprise shortest detected distance between the sensor unit and a nearest detected object, wherein the monitoring unit may be configured to initiate the time measuring function, if the received distance corresponds substantially to a reference distance range representing a distance between the sensor unit and the landing call device.

The reference distance range may be adjusted by the monitoring unit by means of a continuous learning during the operation of the system or the reference distance range may be predefined.

The message may be provided to the monitoring unit in response to the detection of the at least one event indicating the generation of an elevator call or after a predefined monitoring period has elapsed.

The sensor unit may be retrofitted to an existing elevator system and independent of the existing elevator system, and/or the monitoring unit may be retrofitted to an existing elevator system and independent of the existing elevator system.

According to a second aspect, a method for detecting an out-of-operation state of an elevator system is provided, wherein the method comprises: detecting, by a sensor unit arranged in a vicinity of a landing call device, at least one event indicating a generation of an elevator call; providing, by the sensor unit, a message indicating the generation of an elevator call to a monitoring unit; initiating, by the monitoring unit, a time measuring function in response to receiving the message from the sensor unit; and monitoring a response of the elevator system to the generated elevator call.

The method may further comprise generating, by the monitoring device, at least one signal indicating an out-of-operation state of the elevator system to an external computing entity in response to a detection that the elevator system is not responding to the generated elevator call in an expected manner during a predefined delay time after initiating the time measuring function.

Alternatively, the method may further comprise: providing, by the monitoring unit, the monitored response to an external computing entity for detecting an out-of-operation state of an elevator system; and generating, by the external computing entity, an indication that the elevator system is out-of-operation, in response to a detection that the elevator system is not responding to the generated elevator call in an expected manner during a predefined delay time after initiating the time measuring function.

The sensor unit may comprise a first sensor device for detecting a first event indicating the generation of an elevator call within a detection zone of the first sensor device, wherein the first event may be one of the following: motion of an object, gesture of an object, a change in a distance between the sensor unit and a nearest detected object.

The sensor unit may further comprise a second sensor device for detecting a second event within a detection zone of the second sensor device before detection of the first event by the first sensor device, wherein the second event may be a motion of an object or a gesture of an object.

The method may further comprise waking up the sensor unit from a sleep mode in response to a detection of the second event by the second sensor device and initiating a monitoring mode of the first sensor device for a predefined monitoring period.

Moreover, if the detected first event is the change in a distance between the sensor unit and a nearest detected object, the message may further comprise shortest detected distance between the sensor unit and a nearest detected object, wherein the method may further comprise initiating, by the monitoring unit, the time measuring function, if the received distance corresponds substantially to a reference distance range representing a distance between the sensor unit and the landing call device.

The reference distance range may be adjusted by the monitoring unit by means of a continuous learning during the operation of the system or the reference distance range may be predefined.

The message may be provided to the monitoring unit in response to the detection of the at least one event indicating the generation of an elevator call or after a predefined monitoring period has elapsed.

DESCRIPTION OF THE EXEMPLIFYING EMBODIMENTS

FIG.1illustrates schematically a simple example of a system100according to the invention for detecting an out-of-operation state of an elevator system. With the term “out-of-operation state of the elevator system”, i.e. out-of-service state of the elevator system, is meant throughout this application any condition of the elevator system, wherein the elevator system is not able to serve its purpose, i.e. the elevator car is not able to serve elevator call(s) generated for said elevator car, e.g. the movement of the elevator car is stopped. The out-of-operation state may be caused e.g. by technical failure, vandalism, etc. The system100comprises a monitoring unit102for monitoring one or more operations of the elevator system200, and a sensor unit104comprising sensor device(s). The system100may further comprise an external computing entity106. The monitoring unit102and the sensor unit104are communicatively coupled to each other. The communication between the monitoring unit102and the sensor unit104may be based on any known wireless technologies. Preferably, the communication between the monitoring unit102and the sensor unit104may be based on one or more medium-range wireless radio frequency technologies, e.g. sub-gigahertz frequency technologies, in order to enable long distance communication through concrete walls and/or floors. One example of the sub-gigahertz frequency technology may be LoRa (Long Range). However, the invention is not limited to that and any other sub-gigahertz frequency technologies may be used.

The external computing entity106may be one of the following: a cloud server, a service center, a data center. The external entity herein means an entity that locates separate from the elevator system200. The implementation of the external computing entity106may be done as a stand-alone entity or as a distributed computing environment between a plurality of stand-alone devices, such as a plurality of servers providing distributed computing resource. The monitoring unit102and the external computing entity106are communicatively coupled to each other. The communication between the monitoring unit102and the external computing unit106may be based on one or more known communication technologies, either wired or wireless.

FIG.2illustrates schematically an example elevator environment wherein the embodiments of the invention may be implemented as will be described. The example elevator environment illustrated inFIG.2is an elevator system200, which may comprise an elevator control system for controlling the operation of the elevator system200, an elevator car202, and a hoisting machine configured to drive the elevator car202along an elevator shaft204between landings206. For sake of clarity the elevator control system and the hoisting machine are not illustrated inFIG.2. Each landing206comprises a landing door210. In the example elevator environment200ofFIG.2the monitoring unit102is arranged to the elevator car202travelling inside the elevator shaft204between the landings206. However, the physical location of the monitoring unit102in the elevator system200is not limited. InFIG.2only a part of the elevator shaft204comprising one landing206is illustrated, but the elevator shaft204may comprise any number of landings. In the example elevator environment200ofFIG.2the sensor unit102is arranged in a vicinity of a landing call device208residing in said landing206. The sensor unit104may be arranged to any landing206of the elevator system200. Preferably, the sensor unit104may be arranged to the landing206having the main entrance. The system100may further comprise more than one sensor unit104arranged to one or more other landings206in order to monitor condition of the elevator system200from more than one landing206of the elevator system200.

The landing call device208, e.g. a landing call panel, comprise one or more elevator user interface buttons, e.g. elevator landing call button, for generating an elevator call, e.g. a landing call, in order to control at least one operation of the elevator system, e.g. for moving the elevator car202to a desired landing206. The generated elevator call may comprise information of the landing206from which the elevator call is generated. Furthermore, the elevator call may comprise information of the direction, i.e. upwards or downwards, to which elevator car202is desired to travel.

The sensor unit104is configured to detect at least one event indicating a generation of an elevator call, e.g. a landing call. In other words, a detection of the at least one event by the sensor unit104indicates that a user, e.g. a passenger, is assumed to give the elevator call or is attempting to give the elevator call via the landing call device208, e.g. by pushing or touching one or more buttons of the landing call device208. The sensor unit104according to the invention is not configured to control the operation of the elevator system200. The actual elevator call generated via the landing call device208is provided to the elevator control system, which is configured to control the operation of the elevator system200. The sensor unit104according to the invention is configured to indicate the generation of elevator call by detecting at least one event indicating the generation of the elevator call for detecting an out-of-operation state of the elevator system200. In response to the detection of the at least one event indicating the generation of the elevator call, the sensor unit104is configured to provide a message indicating the generation of the elevator call to the monitoring unit102. Alternatively, the sensor unit104may be configured to provide the message indicating the generation of an elevator call to the monitoring unit102after a predefined monitoring period has elapsed and at least one event indicating the generation of an elevator call is detected during said monitoring period. The predefined monitoring period may be a fixed duration, e.g. between 30 to 45 seconds. The sensor unit104may be configured to be in a monitoring mode for the predefined monitoring period during which the sensor device(s) of the sensor unit104are configured to monitor, i.e. measure, in order to detect the event indicating the generation of the elevator call. Providing of the message from the sensor unit104to the monitoring unit102only if the at least one event is detected minimizes radio transmissions, i.e. the communication, from the sensor unit104to the monitoring unit102, which in turn reduces power consumption of the sensor unit104.

The monitoring unit102is configured to initiate a time measuring function in response to receiving the message from the sensor unit104. The time measuring function comprises determining, i.e. counting or measuring, time elapsed from the assumed generation of the elevator call via the landing call device208. The time measuring function may be performed by a timer or any other entity of the monitoring unit102. After initiating the time measuring function the monitoring unit102is configured to monitor a response of the elevator system200to the generated elevator call.

According to an embodiment of the invention, in response to a detection that the elevator system200is not responding to the generated elevator call in an expected manner during a predefined delay time after initiating the time measuring function, the monitoring unit102may be configured to generate at least one signal indicating an out-of-operation state of the elevator system200to the external computing entity106. The response of the elevator system200to the generated elevator call in the expected manner may be that the elevator car202arrives at the desired landing206, i.e. the landing206in which the landing call device208resides from which the elevator call is generated. In other words, if the monitoring unit102detects that the elevator car202has not arrived at the desired landing206, i.e. the landing206in which the landing call device208resides from which the elevator call is generated, when the predefined delay time has elapsed after initiating the time measuring function, the monitoring unit102may be configured to generate the at least one signal indicating an out-of-operation state of the elevator system200to the external computing entity106. The monitoring unit102may comprise one or more sensor devices, e.g. accelerometer and/or magnetometer, for detecting the position of the elevator car202inside the elevator shaft204in order to detect whether the elevator car202has arrived at the desired landing206. The monitoring unit102may further comprise one or more other sensor devices, e.g. gyroscope inclinometer, pressure sensor, temperature sensor, microphone, current sensor, etc., for detecting at least one operation of the elevator system200and/or for providing operational data of the elevator system200. In response to receiving the at least one signal indicating the out-of-operation state of the elevator system200, the external computing entity106may be configured to generate an indication that the elevator system200is out of operation to instruct a maintenance personnel to fix, i.e. repair, the elevator system200, for example.

According to an embodiment of the invention, the monitoring unit102may be configured to provide the monitored response of the elevator system200to the external computing entity106. The external computing entity106may then be configured to generate an indication that the elevator system200is out-of-operation, e.g. to instruct a maintenance personnel to fix, i.e. repair, the elevator system200, in response to a detection that the elevator system200is not responding to the generated elevator call in the expected manner during the predefined delay time after initiating the time measuring function. In other words, if the external computing entity106detects from the monitored response received from the monitoring unit102that the elevator car202has not arrived at the desired landing206, i.e. the landing206in which the landing call device208resides from which the elevator call is generated, when the predefined delay time has elapsed after initiating the time measuring function, the external computing entity may be configured to generate the indication that the elevator system200is out-of-operation.

The detection that the elevator system200is not responding to the generated elevator call in the expected manner during the predefined delay time indicates that the elevator system200is in the out-of-operation state. The predefined delay time may be defined based on a typical response time of the elevator system200, e.g. a typical waiting time of the elevator car202to arrive said landing206. The delay time may depend e.g. on the number of landings206of the elevator system200and/or typical utilization rate of the elevator system200. The delay time may be e.g. between 30 to 45 seconds.

The invention enables that the repair of the elevator system200may be expedited in order to improve the availability of the elevator system200, i.e. the time that elevator system200is in operation. According to an example, the out-of-operation indication may be provided directly from the external computing entity106to a mobile terminal, e.g. mobile phone or tablet computer, of the maintenance personnel.

According to an embodiment of the invention, the sensor unit104may comprise a first sensor device302afor detecting a first event indicating the generation of an elevator call within a detection zone304aof said first sensor device302a. According to another embodiment, the sensor unit104may further comprise a second sensor device302bfor detecting a second event within a detection zone304bof the second sensor device302bbefore detection of the first event by the first sensor device. As discussed above the sensor unit104is arranged in the vicinity of the landing call device208, which means that the sensor unit104is arranged so that the detection zone304a,304bof the sensor device302a,302bextends, i.e. covers, at least the landing call device208. Preferably, the sensor unit104may be arranged above the landing call device208so that the detection zone304a,304bof the sensor device302a,302bis directed substantially downwards towards the landing call device208is illustrated inFIGS.3A-3B and4A-4C.

The detection zone304a,304bof the sensor device302a,302bmay be defined by a field of view (FOV) of the sensor device302a,302b. The FOV of the sensor device302a,302bdefines the angle through which the sensor device302a,302bmay receive electromagnetic radiation. The shape of the FOV of the sensor device302a,302bmay be e.g. conical, rectangle or any other shape. The size of the detection zone304a,304bof the sensor device302a,302bmay be defined so that the size of the detection zone304a,304bis as small as possible in order to avoid faulty detections, but so that it still covers at least the call giving device208in order to avoid missing detections.

FIGS.3A and3Billustrate an example operation of the system according to the invention, wherein the sensor unit104comprises the first sensor device302afor detecting the first event indicating the generation of an elevator call within the detection zone304aof said first sensor device302a. In other words, the sensor unit104of the example ofFIGS.3A and3Bcomprises only the first sensor device302afor detecting one event, i.e. the first event, indicating the generation of an elevator call within the detection zone304aof said first sensor device302a. This enables a simple configuration of the sensor unit104. The first sensor device302amay comprise a motion sensor, i.e. occupancy sensor, e.g. a passive infrared sensor (PIR), for detecting an event being a motion of an object306a,306b. Alternatively, the first sensor device302amay comprise a gesture sensor, e.g. infrared based gesture sensor, for detecting an event being a gesture of an object306a,306b. Alternatively, the first sensor device302amay comprise a distance sensor, e.g. a proximity sensor, for detecting an event being a change in a distance between the sensor unit104and a nearest detected object306a,306b. Alternatively, the first sensor device302amay comprise a thermal imaging sensor or an optical imaging device, e.g. a camera, for detecting an event being a motion of an object306a,306b. The object may be a passenger306b, who is attempting to give the elevator call via the landing call device208, e.g. by pushing or touching one or more buttons of the landing call device208.

The sensor unit104may be powered by one or more batteries, capacitors, or solar cells in order to avoid cumbersome powering from mains. However, this may limit the power available for the components of the sensor unit104. Different type sensor devices may have different power consumption characteristics. Typically, the distance sensors, e.g. proximity sensors, consume more power than the motion sensors. For example, the motion sensors may consume e.g. approximately 1 microampere at 3 volts and the distance sensors, e.g. proximity sensors, may consume e.g. approximately few milliamperes at 3 volts. Thus, from the power consumption point of view, the use of the motion sensor as the first sensor device302ainstead of the proximity sensor, may be preferable. However, the different type sensor devices may also have different sized detection zones304a,304b. Typically, the motion sensors may have significantly wider detection zone304a,304bthan the distance sensors, e.g. proximity sensors. Thus, from the detection accuracy point of view, the use of the proximity sensor may be preferable, because motion sensors may not be sufficiently accurate to detect whether the elevator call was generated by the passenger via the landing call device or not. It may be possible that someone only passes by the landing call device208without making the landing call, but when he passes by the landing call device208, he passes through the detection zone304a,304bof the motion sensor causing a false detection of motion within the detection zone304a,304b.

In the example situation ofFIG.3Aa passenger is not within the detection zone of the first sensor device302acausing that none of the above disclosed events is detected by the first sensor device302a. In example situation ofFIG.3Ba passenger306bhas arrived within the detection zone304aof the first sensor device302acausing that the first sensor device302adetects at least one of the above disclosed events depending on the used sensor device302a. The sensor unit104is configured to provide a message indicating the generation of the elevator call to the monitoring unit102and the monitoring unit102is configured to initiate the time measuring function in response to receiving the message from the sensor unit104as discussed above. After initiating the time measuring function the monitoring unit102is configured to monitor the response of the elevator system200to the generated elevator call. In response to a detection that the elevator system200is not responding to the generated elevator call in an expected manner during the predefined delay time after initiating the time measuring function, the monitoring unit102may be configured to generate the at least one signal indicating an out-of-operation state of the elevator system200to the external computing entity106as discussed above. Alternatively, the monitoring unit102may be configured to provide the monitored response of the elevator system200to the external computing entity106and the external computing entity106may be configured to generate an indication that the elevator system200is out-of-operation, in response to the detection that the elevator system200is not responding to the generated elevator call in the expected manner during the predefined delay time after initiating the time measuring function as discussed above.

If the first event detected by the first sensor device302ais the change in a distance between the sensor unit104and a nearest detected object306a,306b, the message may further comprise shortest detected distance between the sensor unit104and the nearest detected object306a,306b. In the example situation ofFIG.3Athe passenger306bis not within the detection zone304aof the first sensor device302acausing that the floor306aat the landing206is the nearest object to the sensor unit104and the distance between the sensor unit104and the nearest object306a,306bthat the first sensor device302adetects is the distance DFbetween the sensor unit104and the floor306a.

In the example situation ofFIG.3Ba passenger306bhas arrived within the detection zone304aof the first sensor device302acausing that the first sensor device302adetects a change, e.g. reduction, in the distance between the between the sensor unit104and the nearest detected object306a,306b. In this case the passenger306bis the nearest object to the sensor unit104and the distance between the sensor unit104and the nearest object306a,306bthat the first sensor device302adetects is the distance DPbetween the sensor unit104and the passenger306b. Thus, in this case the shortest detected distance between the sensor unit104and the nearest detected object306a,306bis the distance DPbetween the sensor unit104and the passenger306b. The change in the distance between the sensor unit104and the nearest detected object indicates that the elevator call is generated or at least the passenger306b, is in the vicinity of the landing call device208attempting to give the elevator call via the landing call device208.

The monitoring unit102may be configured to initiate the time measuring function, if the received distance corresponds substantially to a reference distance range representing a distance between the sensor unit104and the landing call device208, i.e. the received distance is substantially within the reference distance range. After initiating the time measuring function the monitoring unit102is configured to monitor the response of the elevator system200to the generated elevator call. In response to a detection that the elevator system200is not responding to the generated elevator call in an expected manner during the predefined delay time after initiating the time measuring function, the monitoring unit102may be configured to generate the at least one signal indicating an out-of-operation state of the elevator system200to the external computing entity106as discussed above. Alternatively, the monitoring unit102may be configured to provide the monitored response of the elevator system200to the external computing entity106and the external computing entity106may be configured to generate an indication that the elevator system200is out-of-operation, in response to the detection that the elevator system200is not responding to the generated elevator call in the expected manner during the predefined delay time after initiating the time measuring function as discussed above.

The reference distance range may be defined throughout this application as a distance range corresponding substantially the distance between the sensor unit104and the landing call device208. The reference distance range may be defined to be e.g. from the distance between the sensor unit104and a first horizontal edge of the landing call device208being closest to the sensor unit104, e.g. upper edge of the landing call device208, to the distance between the sensor unit104and a second horizontal edge of the landing call device208being furthermost from the sensor unit104, e.g. lower edge of the landing call device. The reference distance range may be adjusted by the monitoring unit102by applying continuous learning during the operation of the system100. In other words, the monitoring unit104may utilize the detected distances to adjust the reference distance range to learn the distance that corresponds to the distance from the sensor unit104to the landing call device208versus the distance from the sensor unit104to the floor306a. Alternatively, the reference distance range may be pre-defined during provisioning of the sensor unit104.

When the detected distance is within the reference distance range, it indicates that a user e.g. the passenger306a, attempts to give the elevator call via the landing call device208, e.g. by pushing or touching one or more buttons of the landing call device208, which causes the reduction, i.e. change, of the detected distance between the sensor unit104and the nearest object306a,306b.

FIGS.4A-4Cillustrate another example operation of the system according to the invention, wherein the sensor unit104comprises further the second sensor device302bfor detecting the second event within the detection zone304bof the second sensor device302bbefore detection of the first event by the first sensor device302a. In other words, the sensor unit104of the example ofFIGS.4A-4Ccomprises the second sensor device302bfor detecting the second event within the detection zone304bof the second sensor device302bbefore detection of the first event by the first sensor device302aand the first sensor device302afor detecting the first event within the detection zone304aof the first sensor device302a. The second detection zone304bmay be wider, i.e. broader, than the first detection zone304a. The use of two sensor devices302a,302bhaving different size detection zones304a,304bimproves the accuracy of the detection of the generation of the elevator call. In the examples ofFIGS.4A-4C, the first sensor device302aand the second sensor device302bare arranged inside a single unit, i.e. the sensor unit104. However, this is just one embodiment of the invention and at least one of the first sensor device302aand the second sensor device302bmay be implemented as external sensor device arranged, i.e. located, physically separately from the sensor unit104.

The sensor unit104may be powered by one or more batteries, capacitors, or solar cells in order to avoid cumbersome powering from mains. However, this may limit the power available for the components of the sensor unit104. Thus, in order to avoid need for large sized and weighed batteries, the sensor unit104may be configured to be mainly in a sleep mode.

The sensor unit104may be configured to wake up from a sleep mode in response to a detection of the second event by the second sensor device302b. In the sleep mode the sensor unit104with the exception of the second sensor device302bmay be arranged in a low power consumption mode or may be turned off. This means that the sensor unit104is mainly in the sleep mode and waits for an interrupt signal from the second sensor device302bindicating the detection of the second event by the second sensor device302b. This allows a reduced power consumption of the full, i.e. whole, sensor unit104. As discussed above, different type sensor devices may have different power consumptions. Typically, the distance sensors, e.g. proximity sensors, consume more power than motion sensors. For example, the motion sensors, e.g. a passive infrared sensor (PIR), may consume e.g. approximately 1 microampere at 3 volts and the distance sensors, e.g. proximity sensors, may consume e.g. approximately few milliamperes at 3 volts. Thus, it may be preferable to use a motion sensor as the second sensor device302band a distance sensor, e.g. proximity sensor, as the first sensor device302a. This enables very low power consumption, i.e. power consumption of the motion sensor, during the sleep mode of the sensor unit104. Moreover, as discussed above, the different type sensor devices may also have different sized detection zones304. Typically, the motion sensors may have significantly wider detection zone304a,304bthan the distance sensors, e.g. proximity sensors. Thus, from the detection accuracy point of view, the use of the proximity sensor as the first sensor device302amay be preferable. According to a non-limiting example the FOV of the proximity sensor may be approximately 10 degrees by 10 degrees conical FOV from a receiver of the proximity sensor. The FOV of the motion sensor may be such that the motion sensor is configured to detect an object closer than approximately one meter to the landing call device208. Alternatively, a gesture sensor, e.g. infrared based gesture sensor; thermal imaging sensor; or optical imaging device, e.g. a camera, may be used as the second sensor device302b. For example, in a simple example implementation of the invention a generic landing area camera arranged to image the landing area may be used as the second sensor device302band the generic landing are camera may be used to detect the second event in order to wake up the rest of the sensor unit104including the first sensor device302a.

In the example situation ofFIG.4Aa passenger306bis not within the detection zone304bof the second sensor device302b. Thus, the sensor unit104is in the sleep mode waiting for the interrupt signal from the second sensor device302b. In the example situation ofFIG.4B, a passenger306bhas arrived within the detection zone304bof the second sensor device302b, i.e. the second sensor device302bdetects a second event within the first detection zone304b. In response to the detection of the second event by the second sensor device302b, the sensor unit104is configured to wake up from the sleep mode. Depending on the type of the second sensor device302bthe second event may be e.g. motion or gesture an object within the detection zone304bof the second sensor device302b.

After the sensor unit104is waked up, the sensor unit104may be configured to initiate a monitoring mode of the first sensor device302afor a predefined monitoring period. The predefined monitoring period may be a fixed duration, e.g. 30 seconds or longer, if the second sensor device302bcontinues to detect the second event within the second detection zone304bafter the waking up the sensor unit104. During the monitoring period the first sensor device302ais configured to monitor, i.e. measure, in order to detect the first event within the first detection zone304a.

In the next chapters the invention is described by using a distance sensor, e.g. a proximity sensor, as the first sensor device302a. However, the invention is not limited to that and any other type of sensor device, e.g. a gesture sensor, e.g. infrared based gesture sensor; thermal imaging sensor; or optical imaging device, e.g. a camera, may be used as the first sensor device302a. In response to detecting the first event indicating a generation of an elevator call by the first sensor device302awithin the detection zone304aof the first sensor device302a, the sensor unit104is configured to provide the message indicating the generation of the elevator call to the monitoring unit104, which is configured to initiate the time measuring function in response to receiving the message from the sensor unit102. After providing the message to the monitoring unit102, the sensor unit104goes back to the sleep mode.

After initiating the time measuring function the monitoring unit102is further configured to monitor the response of the elevator system200to the generated elevator call. In response to a detection that the elevator system200is not responding to the generated elevator call in an expected manner during the predefined delay time after initiating the time measuring function, the monitoring unit102may be configured to generate the at least one signal indicating an out-of-operation state of the elevator system200to the external computing entity106as discussed above. Alternatively, the monitoring unit102may be configured to provide the monitored response of the elevator system200to the external computing entity106and the external computing entity106may be configured to generate an indication that the elevator system200is out-of-operation, in response to the detection that the elevator system200is not responding to the generated elevator call in the expected manner during the predefined delay time after initiating the time measuring function.

When the first sensor device302ais a distance sensor, the first event is a distance between the sensor unit104and a nearest detected object within the detection zone304aof the first sensor device302aand the message indicating the generation of an elevator call provided to the monitoring unit102may further comprise shortest detected distance between the sensor unit104and the nearest detected object306a,306b. After providing the message to the monitoring unit102, the sensor unit104goes back to the sleep mode.

In the example situation ofFIG.4B, the passenger is within the detection zone304bof the second sensor device302b, but not within the detection zone304aof the first sensor device302a. Thus, the floor306aof the landing206is the nearest object306a,306bto the sensor unit104and the distance between the sensor unit104and the nearest object306a,306bthat the first sensor device302adetects is the distance DFbetween the sensor unit104and the floor306a.

In the example situation ofFIG.4C, the passenger306bis within the detection zone304aof the first sensor device302acausing that the first sensor device302adetects a change, e.g. reduction, in the distance between the between the sensor unit104and the nearest detected object306a,306b. In this case the passenger306bis the nearest detected object to the sensor unit104and the distance between the sensor unit104and the nearest object306a,306bthat the first sensor device302adetects is the distance DPbetween the sensor unit104and the passenger306b. Thus, in this case during the predefined monitoring period the shortest detected distance between the sensor unit104and the nearest detected object306a,306bis the distance DPbetween the sensor unit104and the passenger306b. The change in the distance between the sensor unit104and the nearest detected object indicates that the elevator call is generated or at least the passenger306bis in the vicinity of the landing call device208attempting to give the elevator call via the landing call device208.

The monitoring unit102may be configured to initiate the time measuring function, only if the received distance, i.e. the shortest detected distance, corresponds substantially to the reference distance range representing a distance between the sensor unit104and the landing call device208, i.e. the received distance is substantially within the reference distance range as discussed above. After initiating the time measuring function the monitoring unit102may further be configured to monitor the response of the elevator system200to the generated elevator call. In response to the detection that the elevator system200is not responding to the generated elevator call in an expected manner during the predefined delay time after initiating the time measuring function, the monitoring unit102may be configured to generate the at least one signal indicating an out-of-operation state of the elevator system200to the external computing entity106as discussed above. Alternatively, the monitoring unit102may be configured to provide the monitored response of the elevator system200to the external computing entity106and the external computing entity106may be configured to generate an indication that the elevator system200is out-of-operation, in response to the detection that the elevator system200is not responding to the generated elevator call in the expected manner during the predefined delay time after initiating the time measuring function as discussed above.

Above the invention is described relating to the system100according to the invention. Next an example of a method for detecting an out-of-operation state of an elevator system according to the invention is described by referring toFIG.5, which illustrates schematically the invention as a flow chart. At the step510, the sensor unit104detects at least one event indicating a generation of an elevator call. At the step520, the sensor unit104provides a message indicating the generation of an elevator call to the monitoring unit102. The message may be provided to the monitoring unit102in response to the detection of the at least one event indicating the generation of an elevator call. Alternatively, the sensor unit104may provide the message to the monitoring unit102after a predefined monitoring period has elapsed. The predefined monitoring period may be a fixed duration, e.g. between 30 to 45 seconds. The sensor unit104may be in a monitoring mode for the predefined monitoring period during which the sensor device(s) of the sensor unit104are configured to monitor, i.e. measure, in order to detect the at least one event. At the step530, the monitoring unit102initiates a time measuring function in response to receiving the message from the sensor unit104. At the step540, the monitoring unit102monitors the response of the elevator system200to the generated elevator call.

As discussed above relating to the system100, the sensor unit104may comprise the first sensor device302afor detecting a first event indicating the generation of an elevator call within the detection zone304aof the first sensor device302aat the step510. The first event that may be detected with the first sensor device302amay be one of the following: motion of an object, gesture of an object, a change in a distance between the sensor unit and a nearest detected object.

Furthermore, as also discussed above relating to the system100, the sensor unit104may further comprise the second sensor device302bfor detecting the second event within the detection zone304bof the second sensor device302bbefore detection of the first event by the first sensor device302a.FIG.5Billustrates schematically an example of a method according to the invention, wherein the step510of detecting the at least one event comprises detecting first the second event within the detection zone304bof the second sensor device302band then detecting the first event within the detection zone304aof the first sensor device302a. At the step504, the sensor unit104wakes up from a sleep mode and initiates a monitoring mode of the first sensor device302afor the predefined monitoring period in response to the detection of the second event by the second sensor device302bat the step502. The second event may be motion or gesture of the object within the detection zone304bof the second sensor device302b.

In response to the detection of the first event at the step506, wherein the first event indicates a generation of an elevator call by the first sensor device302awithin the detection zone304aof the first sensor device302a, the sensor unit104continues to the step520as discussed above and provides the message indicating the generation of an elevator call to the monitoring unit102, which is initiates at the step530the time measuring function in response to receiving the message. After providing the message to the monitoring unit102, the sensor unit104goes back to the sleep mode.

If the first event is a change in a distance between the sensor unit104and a nearest detected object306a,306bwithin the detection zone304aof the first sensor device302a, the message may comprise shortest detected distance between the sensor unit104and the nearest detected object and the method may comprise initiating, by the monitoring unit102, at the step530the time measuring function, only if the received distance corresponds substantially to the reference distance range representing a distance between the sensor unit104and the landing call device208. This is illustrated with the optional step550inFIG.5A. After providing the message to the monitoring unit102, the sensor unit104goes back to the sleep mode. After the initiating step530the method continues as described above.

Next another example of the method according to the invention is described by referring toFIGS.6A and6Billustrating further embodiments of the invention. In the example ofFIG.6A, after the step530described above at the step620, the monitoring unit102may generate the at least one signal indicating an out-of-operation state of the elevator system to the external computing entity106in response to a detection610that the elevator system200is not responding to the generated elevator call in an expected manner during a predefined delay time after initiating the time measuring function as discussed above. The response of the elevator system200to the generated elevator call in the expected manner may be that the elevator car202arrives at the desired landing206, i.e. the landing206in which the landing call device208resides from which the elevator call is generated. In other words, if the monitoring unit102detects at the step610that the elevator car202has not arrived at the landing206in which the landing call device208resides, when the predefined delay time has elapsed after initiating the time measuring function, the monitoring unit102generates at the step620the at least one signal indicating an out-of-operation state of the elevator system200to the external computing entity106as discussed above.

In the example ofFIG.6B, after the step530described above, at the step630the monitoring unit102may provide the monitored response of the elevator system200to the external computing entity106. At the step640, the external computing entity106may generate an indication that the elevator system200is out-of-operation, in response to a detection at the step640that the elevator system200is not responding to the generated elevator call in the expected manner during the predefined delay time after initiating the time measuring function as discussed above. The response of the elevator system200to the generated elevator call in the expected manner may be that the elevator car202arrives at the desired landing206, i.e. the landing206in which the landing call device208resides from which the elevator call is generated. In other words, if the external computing entity106detects, at the step640, from the received monitored response from the monitoring unit102that the elevator car202has not arrived at the desired landing206, i.e. the landing206in which the landing call device208resides from which the elevator call is generated, when the predefined delay time has elapsed after initiating the time measuring function, the external computing entity106generates at the step650the indication that the elevator system200is out-of-operation as discussed above.

FIG.7illustrates schematically an example of components of the sensor unit104. The sensor unit104may comprise processing unit710comprising one or more processors, a memory unit720comprising one or more memories, a communication unit730, sensor device(s)302,302a,302b, and power supply unit740. The mentioned elements of may be communicatively coupled to each other with e.g. an internal bus. The one or more processors of the processing unit710may be any suitable processor for processing information and control the operation of the monitoring unit102, among other tasks. Preferably, the processing unit710may be implemented as a microcontroller (MCU) with embedded software. The memory unit720may store portions of computer program code725and any other data, and the processing unit710may cause the sensor unit120to operate as described by executing at least some portions of the computer program code725stored in the memory unit720. Furthermore, the one or more memories of the memory unit720may be volatile or non-volatile. Moreover, the one or more memories are 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 invention. The power supply unit740comprises a power source, e.g. one or more batteries or capacitors, for providing power to the components of the sensor unit104. The power supply unit740may further comprise power management controller and/or a power harvester, e.g. one or more solar cells, for providing power to the components of the sensor unit104. The communication unit730provides an interface for communication with any external unit, such as the monitoring unit102, and/or any external systems. The communication unit730may comprise one or more communication devices, e.g. radio transceiver, antenna, etc. The communication unit730may be based on one or more known communication technologies in order to exchange pieces of information as described earlier. As discussed above the communication unit730may be preferably based on one or more medium-range wireless radio frequency technologies, e.g. sub-gigahertz frequency technologies, in order to communicate with the monitoring unit102. The sub-gigahertz frequency technology may be LoRa or any other sub-gigahertz frequency technologies.

The components of the sensor unit104may each be individual component or at least some of the components of the sensor unit104may be integrated on a single substrate or a chip, i.e. a system on a chip (SoC). For example, the microcontroller, the radio transceiver and the power management controller may be integrated in the same system on a chip.

The physical size of the sensor unit104may be substantially small. Preferably, the physical size of the sensor unit104may be such that the components of the sensor unit104may be arranged, i.e. fitted, inside a signalization component, i.e. an indicator element, of the elevator system100without increasing the physical size of the signalization component remarkably. The signalization component may be e.g. a hall lantern unit (such as hall lantern up or hall lantern down) arranged to a landing to instruct a passenger to select a correct elevator car.

FIG.8schematically illustrates an example of components of the monitoring unit102according to the invention. The monitoring unit102may comprise a processing unit810comprising one or more processors, a memory unit820comprising one or more memories, a communication unit830comprising one or more communication devices, one or more sensor devices840and possibly a user interface (UI) unit850. The mentioned elements of may be communicatively coupled to each other with e.g. an internal bus. The one or more processors of the processing unit810may be any suitable processor for processing information and control the operation of the monitoring unit102, among other tasks. The memory unit820may store portions of computer program code825and any other data, and the processing unit810may cause the monitoring unit120to operate as described by executing at least some portions of the computer program code825stored in the memory unit820. Furthermore, the one or more memories of the memory unit820may be volatile or non-volatile. Moreover, the one or more memories are 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 invention. The communication unit830may be based on at least one known communication technologies, either wired or wireless, in order to exchange pieces of information as described earlier. The communication unit830provides an interface for communication with any external unit, such as the sensor unit104, the elevator control system, the external computing entity106, database and/or any external systems. The communication unit830may comprise one or more communication devices, e.g. radio transceiver, antenna, etc. As discussed above the communication unit830may be preferably based on one or more medium-range wireless radio frequency technologies, e.g. sub-gigahertz frequency technologies, in order to communicate with the sensor unit104. The sub-gigahertz frequency technology may be LoRa or any other sub-gigahertz frequency technologies. The one or more sensor devices840may comprise, e.g. accelerometer, magnetometer, gyroscope, inclinometer, pressure sensor, temperature sensor, microphone, current sensor, etc., for detecting at least one operation of the elevator system200and/or for providing the operational data of the elevator system200. The user interface850may comprise I/O devices, such as buttons, keyboard, touch screen, microphone, loudspeaker, display and so on, for receiving input and outputting information. The power for the monitoring unit102may be provided from the mains via a plug or similar. Alternatively or in addition, the monitoring unit102may comprise a rechargeable battery for providing power to enable battery operated monitoring unit, for example in power failure situations.

The sensor unit104and/or the monitoring unit102may be implemented in any elevator system including newly installed elevator systems and already existing, i.e. operating, elevator systems. The sensor unit104may be retrofitted to an existing elevator system and may be completely independent of the existing elevator system. In other words, the sensor unit104may be arranged to already existing elevator system without communicatively coupling the sensor unit104to one or more entities, e.g. control units, of the existing elevator system. The sensor unit104may be only mechanically installed in a physical connection with the elevator system as discussed above. Alternatively or in addition, the monitoring unit102may be retrofitted to an existing elevator system and may be completely independent of the existing elevator system. In other words, the monitoring unit102may be arranged to already existing, i.e. operating, elevator system without communicatively coupling the monitoring unit102to one or more entities, e.g. control units, of the existing elevator system. The monitoring unit102may be only mechanically coupled in physical connection with the elevator system as discussed above. This enables that the system100according to the invention may be implemented in a newly installed elevator system or in already existing elevator system. By implementing the system100according to the invention in already existing elevator system monitoring of condition of already existing elevator system is enabled. Moreover, it enables that the whole system100, the sensor unit104, and/or the monitoring unit102according to the invention do not have any requirements to the elevator system. Because the system100comprising the sensor unit104and/or the monitoring unit102is completely independent of the elevator system, it enables that the system100is substantially easy to install to the elevator system200.

Above the invention is described so that the sensor unit104is used for monitoring the generation of elevator calls by the passengers in order to monitor the condition of the elevator system200. Alternatively or in addition, the sensor unit104according to the invention may be used for monitoring any other activity and/or operation at the landing in which the sensor unit104resides. For example, the sensor unit104may be used for monitoring condition of lighting at said landing206in which the sensor unit104resides.