Patent Description:
Elevator cars traveling in a shaft comprise a number of doors to increase safety by not allowing passengers to access the shaft e.g. during a travel. An operation of the elevator car doors is controlled with high accuracy and a status of the door are constantly monitored. For example, the elevator car should not start the travel unless the doors are closed and, hence, the status of the car doors is linked to other entities in the elevator system with an aim of maintaining and improving the safety of using the elevator system.

In prior art solutions the monitoring of the status of the elevator car doors is based on obtaining measurement data from one or more sensors coupled to a door frame or to the elevator door so as to generate measurement data on the position of the door leaf, or door leaves, with respect to the frame. The sensors applied in prior art solutions are based on detections generated in response to an electrical contact or detections generated in response to a photoelectric phenomenon (cf. infra-red sensors).

In documents <CIT>, <CIT>, and <CIT> it is disclosed various monitoring solutions applied in elevator systems based on different types of sensors.

Drawbacks of the existing solutions are that the sensors may get dirty and their operation may get disturbed. Further, the sensors of the described type are coupled to moving parts of the elevator car doors wherein a mechanical stress experienced by the sensors may break the sensors and, hence, cause challenges to the whole elevator system. Further, in the existing solutions the sensors belong to a safety chain of the elevator system, which does not necessary allow access to the sensor data by external entities.

Hence, there is need to introduce novel approaches for monitoring an operation of the elevator car doors, which at least in part mitigate the drawbacks of the prior art solutions.

An object of the invention is to present an apparatus, a method, a computer program product and an elevator system for detecting a state of an elevator door.

The objects of the invention are reached by an apparatus, a method, a computer program product, and an elevator system as defined by the respective independent claims.

According to a first aspect of the present invention, an apparatus for detecting a state of an elevator door is provided, the apparatus comprising at least one processor; at least one memory including computer program code; communication means; I/O components; the at least one processor, the at least one memory, the communication means and the I/O components communicatively coupled to each other via a bus, wherein the at least one memory and the computer program code configured to, with the at least one processor, cause the apparatus to perform: determine, on a basis of a pressure data, at least one indicator value indicative of a change in a pressure by applying a statistical analysis to the pressure data over a predefined time window; compare the at least one indicator value to a respective reference value; and set, in accordance with a comparison between the at least one indicator value and the respective reference value, a detection result to express one of the following: (i) the elevator door is open, (ii) the elevator door is closed.

For example, the apparatus may be configured to perform the statistical analysis by a determination of a variance over the predefined time window for determining the at least one indicator value indicative of the change in the pressure. Also, the apparatus may be configured to perform the determination of the variance by at least one of: on a first order representing a noise level of the pressure data, on a second order representing a variability of the noise level, on a third order representing an acceleration of the noise level.

The apparatus may further be configured to: generate, in response to the detection result expressing that the elevator door is open, a control signal for calibrating an operation to at least one of: a positioning system of an elevator car in the elevator shaft; an accelerometer associated to the elevator car. Moreover, the apparatus may be at least one of: a measurement device coupled to the elevator car; an elevator controller; a server device residing in a communication network.

The apparatus may also be arranged to receive the pressure data from at least one pressure sensor configured to measure the pressure from at least one of: an elevator shaft; in the elevator car. For example, the apparatus may be configured to receive the pressure data representing the pressure in the elevator shaft from at least one pressure sensor arranged in at least one of following manner: on a roof of the elevator car; on a wall of the elevator shaft; air vent arranged to transfer air between the elevator car and the elevator shaft.

According to a second aspect of the present invention, a method for detecting a state of an elevator door is provided, the method, performed by an apparatus comprises: determining, on a basis of a pressure data, at least one indicator value indicative of a change in a pressure by applying a statistical analysis to the pressure data over a predefined time window; compare the at least one indicator value to a respective reference value; and set, in accordance with a comparison between the at least one indicator value and the respective reference value, a detection result to express one of the following: (i) the elevator door is open, (ii) the elevator door is closed.

For example, the statistical analysis may comprise a determination of a variance over the predefined time window for determining the at least one indicator value indicative of the change in the pressure. Also, the determination of the variance may be performed by at least one of: on a first order representing a noise level of the pressure data, on a second order representing a variability of the noise level, on a third order representing an acceleration of the noise level.

Still further, the method may also comprise: generating, in response to the detection result expressing that the elevator door is open, a control signal for calibrating an operation to at least one of: a positioning system of an elevator car in the elevator shaft; an accelerometer associated to the elevator car.

The method may also further comprise: receiving the pressure data from at least one pressure sensor configured to measure the pressure from at least one of: an elevator shaft; in the elevator car. The pressure data representing the pressure in the elevator shaft may e.g. received from at least one pressure sensor arranged in at least one of following manner: on a roof of the elevator car; on a wall of the elevator shaft; air vent arranged to transfer air between the elevator car and the elevator shaft.

According to a third aspect of the present invention, a computer program product for detecting a state of an elevator door according to claim <NUM> is provided.

According to a fourth aspect of the present invention, an elevator system is provided, the elevator system comprising: at least one elevator car, and an apparatus according to the first aspect as defined in the foregoing description.

The features recited in dependent claims are mutually freely combinable within the scope of the appended claims unless otherwise explicitly stated.

Some aspects of the present invention are described in the following by referring to an example schematically illustrated in <FIG> wherein it is illustrated some elevator entities as well as other entities of an elevator system. In accordance with the example an elevator car <NUM> comprising a number of elevator doors <NUM> is provided. The elevator doors <NUM> in the context of <FIG> shall be understood to cover at least one of the following: an elevator car door, a landing door. In case there are both doors installed, the door system may be implemented so that the elevator doors <NUM> are controlled to open and close in a synchronous manner e.g. by utilizing so-called door coupler solution for connecting the doors together when operated.

Further, the elevator system comprises a measurement device <NUM> associated with the elevator car <NUM>, e.g. by coupling the measurement device <NUM> on a roof of the elevator car <NUM>, so that the measurement device <NUM> may travel along the elevator car <NUM> in the travel path, such as in the shaft. The measurement device <NUM> may comprise at least one sensor <NUM> being suitable for measure pressure of an environment. An applicable sensor <NUM> may be a pressure sensor like a barometer. The at least one pressure sensor <NUM> may be housed in the measurement device <NUM> or it may be external to the housing of the measurement device <NUM> but communicatively connected in a wired or in a wireless manner to the measurement device <NUM>. Hence, the measurement device <NUM> may comprise a communication interface to communicate with the pressure sensor <NUM>, but also with other entities, such as an elevator controller <NUM> or an entity, such as a server device <NUM>, residing in a cloud computing environment, but serving at least the measurement device <NUM> in a manner as is described in the forthcoming description. In a selection of the location of the pressure sensor <NUM> an implementation of the elevator door is advantageously taken into account. The selection may e.g. be done so that it is arranged in a position wherein the pressure may be measured, and possible detections in a change of the pressure may be performed, in accordance with a state of the elevator doors. Applicable locations may e.g. be inside the elevator car <NUM>, or on an external surface of the elevator car <NUM>, such as on a roof of the elevator car <NUM> as schematically illustrated in <FIG>. In some examples, the pressure sensor <NUM> may be arranged in the elevator shaft, e.g. in a vicinity of opening of the elevator shaft to the floors e.g. covered by the landing door, and the respective pressure sensors <NUM> may be arranged to communication e.g. in a wireless manner with e.g. the measurement device <NUM> for delivering the data representing the pressure experienced in the location of the pressure sensor <NUM> in question.

As derivable also from <FIG> the communication to the elevator controller <NUM> and/or the server device <NUM> residing in a communication network and the measurement device <NUM> may be performed in a wired manner or in a wireless manner. The wireless implementation to the server device <NUM> may be implemented at least in part by utilizing a wireless communication resources provided by a mobile communication network providing service in an area in which the elevator system and, hence, the measurement device <NUM> is arranged to operate. For sake of clarity it is worthwhile to mention that in some examples the measurement device <NUM> may be arranged to perform its task without communicative connection to the server device <NUM> or to the elevator controller <NUM> at least in a direct manner. Further, in some examples the communication of the measurement device <NUM> to the server device <NUM> may be arranged to be performed through the elevator controller <NUM>. Still further, in addition to the pressure sensor <NUM> the measurement device <NUM> may be configured to receive measurement data from other types of sensors, such as from accelerometers and position sensors, which may at least in part be implemented in the housing of the measurement device <NUM>.

Depending on the implementation a processing of the measurement data obtained from the pressure sensor <NUM> may be performed by the measurement device <NUM>, or raw measurement data may be transmitted by the measurement device <NUM> to another entity, such as the elevator controller <NUM> or the server device <NUM>, for processing. The entity performing the processing of data is now called as an apparatus when describing an example of a method as schematically illustrated in <FIG>.

<FIG> illustrates a non-limiting example on a processing of data for determining a state of an elevator door. The elevator door, as already mentioned, herein corresponds to at least one of: the elevator car door, the landing door and wherein an opening of the respective door, or doors, causes airflow at least between the space in question, such as the shaft or the elevator car <NUM> or even both, and a hall at the landing. In other words, the position of the at least one pressure sensor <NUM> may be selected in accordance with the implementation of the elevator door so as to allow a detection of the pressure in the measurement position, and variations therein in accordance with the state of the elevator door. For example, if the pressure sensor <NUM> resides in the shaft side, e.g. on the roof of the elevator car <NUM> or on the shaft wall, it is necessary that at least the landing door is opened for enabling any detection due to an establishment of a path for air flow between the shaft and the hall. Similarly, if the pressure sensor <NUM> resides inside the elevator car <NUM>, the elevator doors arranged between the volume of the elevator car <NUM> and the hall needs to be opened for performing any detections representing the state of the door due to an establishment of a path for air flow between the elevator car <NUM> and the hall. Still further, the pressure sensor <NUM> may also be arranged in an air vent arranged to transfer air between the elevator car <NUM> and the elevator shaft wherein the pressure sensor <NUM> may receive data representing a state in the pressure at least in the shaft. As derivable from the foregoing description, the at least one pressure sensor <NUM> is configured to collect pressure data in the elevator environment and the apparatus is arranged to determine <NUM>, on a basis of the pressure data, an indicator value indicative of a change in the pressure in the elevator environment, such as in the elevator shaft. The indicator value may be any applicable mathematical parameter derivable from the measurement data, i.e. from the raw measurement data, containing consecutive pressure values received at a sampling frequency of the measurement system. In an advantageous example, the indicator value may be determined so that it reacts rapidly on the changes in the measurement data. In some example, the change may be determined between two consecutive data values, but such an implementation may not necessary be optimal in a sense of reliability of the solution. Hence, a more sophisticated solution is based on a determination the indicator value by applying a statistical analysis to the pressure data over a predefined window. The predefined window may be defined over a time which corresponds to a predefined number of data values since the sampling rate may be dependent on the applied system i.e. on at least the pressure sensor <NUM> capability as well as the communication channel and the processing resources in the apparatus <NUM>.

According to at least some advantageous examples, the statistical analysis may be performed so that an indicator value representing a variance of the data values over the predefined time window is determined. The determination of the variance may be performed by applying a rolling method in the determination of the variance, i.e. a rolling variance, so that the variance is determined for measured pressure data values over consecutive time windows enabling to detect disturbances that are due to environment change comprising at least pressure change during a respective time window. The determination of the rolling variance may be performed for the consecutive time windows e.g. so that at least some of the pressure data values are present in the consecutive time windows. In other words, the time windows are overlapping at least in part. In accordance with some examples, the determination of the variance may advantageously be performed by calculating a variance of a certain order from the pressure data values, such as a first order, a second order or a third order. These orders may be considered in the context of the present solution in such a manner that the first order represents the noise level in the raw data, i.e. in the measurement data values, the second order represents a variability of the noise level (cf. speed) and the variance of the third order represents an acceleration of the noise level. An advantage of using the variance of a selected order in the method in the described manner is that any deviations in the measured pressure data may be detected easier than from the raw data.

In response to a determination <NUM> of the indicator value the apparatus <NUM> may be arranged to compare <NUM> the indicator value to a reference value. The reference value is advantageously defined in advance, e.g. as a fixed value e.g. obtained through trial-error method, and it defines a reference value allowing to perform the comparison so that a conclusion may be made with an acceptable accuracy. For example, the reference value may define a value for the change in a predefined time window so that if the indicator value exceeds the reference value, it may be concluded that the elevator door <NUM> is open. In some examples, the reference value may be defined dynamically e.g. based on previous measurement results received from the at least one pressure sensor <NUM>. In other words, the reference value is not necessarily fixed but may be defined dynamically e.g. so that it is relative to a regular noise level learned from previous samples derived from the previous time windows. As is clear from the context, the at least one reference value is to be selected and/or defined in accordance with the representation of the indicator value, i.e. in accordance with how the indicator value is calculated.

Finally, in step <NUM> the apparatus <NUM> may perform a conclusion, in accordance with the comparison between the indicator value and the reference value, by setting a detection result to express one of the following: (i) the elevator door <NUM> is open, (ii) the elevator door <NUM> is closed. The apparatus <NUM> may be arranged to deliver the detection result to at least one other entity, such as to the elevator controller <NUM>, for further use.

Still further, in some embodiments it is possible to implement the method so that a plurality of indicator values is determined from the raw data, such as variances of a first and a second order. Further, for both of these it is defined respective reference values. As a result, both indicator values are compared to their respective reference values and, the conclusion may be performed based on the comparisons. It is also worthwhile to mention that in case a plurality of indicator values is determined, the respective indicator values need not necessarily be determined from the same set of raw data, but the time window, and, hence, a number of samples may be different for determining the respective indicator values. For example, the conclusion that the elevator door <NUM> is open may e.g. made if both indicator values exceeds their respective reference values. Naturally, other rules for the decision-making may be defined. This kind of implementation which combines a plurality of comparison paths may be advantageous if an improved accuracy is necessary.

In accordance with the example, in case the apparatus <NUM> generates an expression that the elevator door <NUM> is open on the basis of the measurement data obtained from the at least one pressure sensor <NUM> the apparatus <NUM>, or any other entity received the information on that the elevator door <NUM> is open, may be configured to generate a control signal to at least one other entity belonging the elevator system. The generation of the control signal may cause a calibration of the at least one other entity wherein the other entity may be one generating information on a state of the elevator system, or the elevator car <NUM>. This is possible because the detection that the elevator door <NUM> is open confirms that the elevator car <NUM> resides at a landing and that information may e.g. be used for calibrating a positioning system of an elevator car in the elevator shaft or an accelerometer associated to the elevator car. The positioning system may e.g. be such that it generates position information of the elevator car <NUM> in the shaft based on detections of magnetic sensors mounted in the shaft at known intervals.

<FIG> illustrates schematically, as graphs, examples of determining variances of different orders from pressure data values received from a pressure sensor <NUM> (<FIG>). In other words, <FIG> illustrates schematically a magnitude of the pressure data values received from the pressure sensor <NUM> over the time. By applying the rolling variance on a first order or on a second order generates clear deviations in the graph, and based on at least one of these it may be concluded that the elevator door <NUM> is opened. <FIG> illustrates schematically the variance of the first order and <FIG> illustrates schematically the variance of the second order both derived from the measurement data as shown in <FIG>. For sake of clarity it is worthwhile to mention that the x axis in the <FIG> represents time and the y axis represents an intensity of the respective signal. However, the intensities of the signals in the <FIG> are not necessarily in the same scale. Still further, as shown in <FIG> there may be defined respective reference values for the parameter in question. In <FIG> the reference values are labelled with Ref1 (for the variance of the first order; cf. <FIG>) and with Ref2 (for the variance of the second order, <FIG>). Further, the instant of time at which the detection may be made is referred with Td, which is drawn common for all the graphs in <FIG>.

For example, the apparatus may refer to a computing device, such as a server device, a laptop computer, a PC, or any similar data processing device, as schematically illustrated in <FIG> illustrates schematically as a block diagram the apparatus applicable to perform the method in cooperation with other entities, such as with sensors. The apparatus may thus be e.g. the measurement device <NUM>, the elevator controller <NUM>, or the server device <NUM> as discussed in the foregoing description. For sake of clarity, it is worthwhile to mention that the block diagram of <FIG> depicts some components of a device that may be employed to implement an operation of the apparatus. The apparatus comprises a processor <NUM> and a memory <NUM>. The memory <NUM> stores data and computer program code <NUM>. The apparatus further comprises communication means <NUM> for wired and/or wireless communication with other entities, such as with the at least one pressure sensor <NUM>, and other sensors, but also with other entities. Furthermore, I/O (input/output) components <NUM> are arranged, together with the processor <NUM> and a portion of the computer program code <NUM>, to provide a user interface for receiving input from a user, such as from a technician of the elevator system, and/or providing output to the user of the system when necessary. In particular, the user I/O components may include user input means, such as one or more keys or buttons, a keyboard, a touchscreen, or a touchpad, etc. The user I/O components may include output means, such as a display or a touchscreen. The components of the apparatus are communicatively coupled to each other via a bus <NUM> that enables transfer of data and control information between the components.

The memory <NUM> and a portion of the computer program code <NUM> stored therein may be further arranged, with the processor <NUM>, to cause the apparatus, i.e. the device, to perform a method as described in the foregoing de-scription. The processor <NUM> may be configured to read from and write to the memory <NUM>. Although the processor <NUM> is depicted as a respective single component, it may be implemented as respective one or more separate pro-cessing components. Similarly, although the memory <NUM> is depicted as a respective single component, it may be implemented as respective one or more separate components, some or all of which may be integrated/removable and/or may provide permanent / semi-permanent / dynamic / cached storage.

The computer program code <NUM> may comprise computer-executable instructions that implement functions that correspond to steps of the method when loaded into the processor <NUM>. As an example, the computer program code <NUM> may include a computer program consisting of one or more sequences of one or more instructions. The processor <NUM> is able to load and execute the computer program by reading the one or more sequences of one or more instructions included therein from the memory <NUM>. The one or more sequences of one or more instructions may be configured to, when executed by the processor <NUM>, cause the apparatus to perform the method be described. Hence, the apparatus may comprise at least one processor <NUM> and at least one memory <NUM> including the computer program code <NUM> for one or more programs, the at least one memory <NUM> and the computer program code <NUM> configured to, with the at least one processor <NUM>, cause the apparatus to perform the method as described.

The computer program code <NUM> may be provided e.g. a computer program product comprising at least one computer-readable non-transitory medium having the computer program code <NUM> stored thereon, which computer program code <NUM>, when executed by the processor <NUM> causes the apparatus to perform the method. The computer-readable non-transitory medium may comprise a memory device or a record medium such as a CD-ROM, a DVD, a Blu-ray disc, or another article of manufacture that tangibly embodies the computer program. As another example, the computer program may be provided as a signal configured to reliably transfer the computer program.

Still further, the computer program code <NUM> may comprise a proprietary application, such as computer program code for causing an execution of the method in the manner as described.

Any of the programmed functions mentioned may also be performed in firm-ware or hardware adapted to or programmed to perform the necessary tasks.

Moreover, as mentioned a functionality of the apparatus may be shared between a plurality of devices as a distributed computing environment. For example, the distributed computing environment may comprise a plurality of devices as schematically illustrated in <FIG> arranged to implement the method in cooperation with each other in a predetermined manner. For example, each device may be arranged to perform one or more method steps and in response to a finalization of its dedicated step it may hand a continuation of the process to the next device. The devices may e.g. be the measurement device <NUM>, the elevator controller <NUM>, and the server device <NUM>, or any combination of these as long as the measurement data from the at least one pressure sensor <NUM> may be conveyed to the respective entities.

Hence, in accordance with some aspects an elevator is provided wherein the elevator system comprises an apparatus to perform the method as described.

In some examples, the detection result obtained with the method may be confirmed with information from other systems. For example, in some embodiments the detection result is confirmed by obtaining measurement data from an accelerometer and by detecting, based on the measurement data from the accelerometer, that the elevator car stands still at the same time when the pressure data indicates that the elevator door <NUM> is open, it may be concluded that the expression on the state of the elevator door <NUM> is correct. The position information may be utilized in the same manner to confirm the outcome of the method as described.

In case the apparatus is implemented as a stand-alone device it may be associated with an elevator car <NUM> as an independent unit to provide information on a status of the elevator system, and especially on a state of the elevator door <NUM>, to an external entities, such as to a server device residing in a communication network. This kind of implementation may be advantageous if the elevator system is old and there are no possibilities to integrate monitoring devices in the elevator system itself, but only introducing those in the elevator system as independent units. In this manner it is possible to generate data for monitoring purposes of the elevator system in question.

The solution as described in the foregoing description are applied in contexts wherein there is need to understand a state of the elevator door, and use that information for any further use. For example, the information on the state of the elevator door derivable in the described manner may be used for detecting that an elevator car has entered to a floor level, as a non-limiting example.

Claim 1:
An apparatus (<NUM>, <NUM>, <NUM>) for detecting a state of an elevator door, the apparatus (<NUM>, <NUM>, <NUM>) comprising:
at least one processor (<NUM>);
at least one memory (<NUM>) including computer program code (<NUM>);
communication means (<NUM>);
I/O components (<NUM>);
the at least one processor (<NUM>), the at least one memory (<NUM>), the communication means (<NUM>) and the I/O components (<NUM>) communicatively coupled to each other via a bus (<NUM>);
wherein the at least one memory (<NUM>) and the computer program code (<NUM>) configured to, with the at least one processor (<NUM>), cause the apparatus (<NUM>, <NUM>, <NUM>) to perform:
determine (<NUM>), on a basis of a pressure data, at least one indicator value indicative of a change in a pressure by applying a statistical analysis to the pressure data over a predefined time window;
compare (<NUM>) the at least one indicator value to a respective reference value; and
set (<NUM>), in accordance with a comparison between the at least one indicator value and the respective reference value, a detection result to express one of the following: (i) the elevator door is open, (ii) the elevator door is closed.