TECHNICAL FIELD

The invention concerns in general the technical field of elevator systems. More particularly, the invention concerns safety solution of the elevator systems.

BACKGROUND

Safety in all situations is an essential goal in elevator systems. One field of safety in the elevator systems relates to guaranteeing that no person is present in such an area or space with respect to an operation of the elevator that persons may get hurt and/or the elevator may get damaged. An example of such a space is an elevator shaft in which an elevator car and a counter-weight are arranged to travel during the operation of the elevator. Situations in which there may be persons in the shaft may e.g. be when a technician is performing a maintenance of the elevator, or some unauthorized persons have accessed the shaft by force. Without saying this kinds of situations are extremely risky.

Another aspect is that the development in communication technologies have enabled controlling of the operation of the elevator system remotely e.g. from a data centre. This covers also situations in which the elevator system is operated remotely. Also these kinds of operating modes shall follow the safety requirements at least to guarantee that there are no persons in the shaft when remotely calling the elevator system to operate.

There are known solutions for monitoring the elevator shaft. These are mainly based using specific types of sensors to gather data from the shaft so to decide if there exist persons in the shaft e.g. in a path of the elevator car. The applied sensor technologies in the person detection in the elevator solutions are passive infrared (PIR), Doppler radar sensor, time-of-flight (ToF) camera, ToF low resolution sensor, or digital imaging camera. These types of sensors have drawbacks, such as:

• PIR sensor is not sensitive to persons standing still which makes the technology unreliable for elevator applications. Additionally, warm moving parts might cause false detection.

• Doppler radar sensor, that functions mainly as a movement sensor and does not provide distance information, has a drawback that other moving parts in the shaft, such as counter-weight or swaying ropes cause a lot of false detections.

• Typical digital imaging camera requires enough light in the shaft.

• Many applicable sensors are too expensive for the application field of elevators, such as pulsed radar, frequency modulated continuous wave (FMCW) radars, night vision cameras, or ToF sensors. These would also consume a lot of energy which needs to be addressed in the elevator solutions.

An example of a prior art solution with the PIR sensor is disclosed in a document WO 2009/073001 A1 .

Hence, there is room for novel approaches in the field of monitoring the elevator shaft.

SUMMARY

The following presents a simplified summary in order to provide basic understanding of some aspects of various invention embodiments. The summary is not an extensive overview of the invention. It is neither intended to identify key or critical elements of the invention nor to delineate the scope of the invention. The following summary merely presents some concepts of the invention in a simplified form as a prelude to a more detailed description of exemplifying embodiments of the invention. An object of the invention is to present a measurement system, a method, and a computer program for monitoring a presence of a predefined object in an elevator shaft.

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

According to a first aspect, a measurement system for monitoring a presence of a predefined object in an elevator shaft is provided, the measurement system comprising: a thermal sensor unit implemented with a plurality of sensing elements in a form of floating vacuum thermal transistors, TMOS, positioned to generate measurement data from the elevator shaft, and a local control unit associated with the thermal sensor unit for generating an indication on the presence of the predefined object on a basis of the measurement data received from the thermal sensor unit.

For example, the thermal sensor unit may comprise a first portion of the sensing elements in the form of the floating vacuum thermal transistors, TMOS, configured to be exposed to radiation receivable from the predefined object and a second portion of the sensing elements in the form of floating vacuum thermal resistors, TMOS, configured to be shielded from the radiation. The local control unit may be configured to filter out an effect caused by internal self-heating of the thermal sensor unit by using the measurement data obtained from the second portion of the sensing elements in an evaluation of the measurement data obtained from the first portion of the sensing elements.

Furthermore, the measurement system may further comprise: a battery configured to provide electrical power in the measurement system.

Still further, the measurement system may further comprise: a communication interface for transmitting data from the measurement system.

The local control unit associated to the thermal sensor unit may also be configured to generate the indication on the presence of a person in the elevator shaft as the predefined object.

According to a second aspect, an elevator system is provided, the elevator system comprising: an elevator shaft, and at least one measurement system in accordance with the first aspect as defined above.

For example, the measurement system may be arranged to at least one of the following: an elevator car; a pit of the elevator shaft; a top part of the elevator shaft; a counter-weight.

According to a third aspect, a method for monitoring a presence of a predefined object in an elevator shaft is provided, the method comprising: receiving, by a local control unit of a measurement system, measurement data from a thermal sensor unit implemented with a plurality of sensing elements in a form of floating vacuum thermal transistors, TMOS, positioned to generate measurement data from the elevator shaft, and generating, by the local control unit of the measurement system associated with the thermal sensor unit, an indication on the presence of the predefined object on a basis of the measurement data received from the thermal sensor unit.

The indication may e.g. indicate one of the following: the predefined object is present in the elevator shaft; the predefined object is non-present in the elevator shaft. Furthermore, the method may further comprise, prior to generating the indication, a step of filtering out an effect caused by internal self-heating of the thermal sensor unit by using the measurement data obtained from a second portion of the sensing elements of the thermal sensor unit in an evaluation of the measurement data obtained from a first portion of the sensing elements of the thermal sensor unit.

According to a fourth aspect, a computer program is provided, the computer program comprising instructions to cause a control unit of a measurement system according to the first aspect as defined above to execute the steps of the method according to the second aspect as defined .

The expression "a number of” refers herein to any positive integer starting from one, e.g. to one, two, or three.

The expression "a plurality of” refers herein to any positive integer starting from two, e.g. to two, three, or four.

Various exemplifying and non-limiting embodiments of the invention both as to constructions and to methods of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplifying and non-limiting embodiments when read in connection with the accompanying drawings.

The verbs “to comprise” and “to include” are used in this document as open limitations that neither exclude nor require the existence of unrecited features. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated. Furthermore, it is to be understood that the use of “a” or “an”, i.e. a singular form, throughout this document does not exclude a plurality.

BRIEF DESCRIPTION OF FIGURES

The embodiments of the invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings. Figure 1 illustrates schematically a measurement system according to an example.

Figure 2 illustrates schematically an elevator system according to an example.

Figure 3 illustrates schematically a method according to an example.

DESCRIPTION OF THE EXEMPLIFYING EMBODIMENTS

The specific examples provided in the description given below should not be construed as limiting the scope and/or the applicability of the appended claims. Lists and groups of examples provided in the description given below are not exhaustive unless otherwise explicitly stated.

Figure 1 illustrates schematically at least a part of a measurement system 100 according to an embodiment of the present invention. The measurement system 100 is for monitoring a presence of a predefined object in an elevator shaft in order to improve safety in elevator systems. The measurement system 100 shown in Figure 1 illustrates some components of the measurement system 100 and especially at least a part of a measurement portion of the system 100. The measurement system 100 comprises a thermal sensor unit, TSU, 110 implemented with a plurality of sensing elements 1150 being floating vacuum thermal transistors. Such sensing elements area configured detect object based on their temperature, especially against the temperature in the background. This allows them to be configured to detect a person as the predefined object in the elevator shaft. The sensing elements 115, i.e. the floating vacuum thermal transistors, are a specific type of infrared (IR) sensor implemented as TMOS (Thermal Metal Oxide Semiconductor) structures to detect a presence of an object as well as its movement with high accuracy and low-power consumption. The sensing elements may be arranged in a matrix structure and even connected together to act as a single sensing element. This is naturally dependent on the implementation and how the data is intended to be read from the sensing elements. In accordance with an example embodiment the thermal sensor unit 110 comprises a first portion of the sensing elements 115 being the floating vacuum thermal transistors, TMOS, corresponding to first portion of pixels, which are configured to be exposed to radiation receivable from the object, or at least the monitored space. Such sensing elements 115 are drawn with solid lines in Figure 1. Furthermore, in the embodiment the thermal sensor unit 110 may comprise a second portion of the sensing elements 115 being floating vacuum thermal resistors, TMOS, which are shielded from the radiation for a purpose described in the forthcoming description. Such sensing elements 115 are drawn with dashed lines in Figure 1. The shielding may be arranged with a protecting layer 118 arranged to cover the second portion of the sensing elements 115. The protecting layer 118 may be implemented with any applicable material preventing the radiation to enter the sensing elements underneath it. For example, it may be implemented with a foil attached on a surface of the thermal sensing unit 110 e.g. by gluing or in any similar manner. The protecting layer 118 may also be implemented with an adhesive paper or with a tape as further non-limiting examples.

In addition to the thermal sensor unit 110 the system may comprise a local control unit 120 associated with the thermal sensor unit 110 wherein the thermal sensor unit 110 is configured to generate an indication on the presence of the predefined object on a basis of the measurement data received from the thermal sensor unit 110. In other words, the association between the local control unit 120 and the thermal sensor unit 110 may be arranged so that they are communicatively connected so that the control unit 120 may obtain measurement data from the sensing elements of the thermal sensor unit 110. The control unit 120 may be configured to analyse the received measurement data in a predefined manner so as to generate the indication in a manner as mentioned. In accordance with the invention the local control unit 120 may be configured to detect if the measurement data comprises such data which corresponds to a radiation receivable from the predefined object under monitoring. For example, in some embodiments the aim is to monitor a presence of a person, i.e. a human being, in the shaft. Thus, the indication may be generated in response to a detection of thermal radiation specific to the human being in terms of temperature. The electric power to the mentioned entities, i.e. to the local control unit 120 and to the thermal sensor unit 110, may be brought from external sources, like electric power network, with an applicable wiring. However, in some advantageous embodiments the measurement system 100 may comprise a battery unit 130 configured to provide electrical power to the system 100, and at least to the local control unit 120 and to the thermal sensor unit 110. The size of the battery unit 130 in terms of a capability to store energy may be selected based on desired life-time of the measurement system 100 to perform the detection and/or based on possibilities to charge or replace the battery unit 130. The battery implementation is possible in the measurement system 100 as described herein due to a fact that the thermal sensor unit 110 is implemented with such components which consume very little energy during the operation. In support of this the local control unit 120 may also be implemented with components configured to consume as little energy as possible.

As already mentioned, the measurement system 100, and especially the control unit 120, may be configured to generate an indication on a presence of the predefined object in the operation vicinity of the sensing elements, i.e. in the elevator shaft. In other words, the indication may be given in an output signal of the local control unit 120 and the output may be arranged so that that the output signal has two states, a first state indicating a presence of the predefined object and a second state indicating non-presence of the predefined object. In some example embodiments an information on the indication at a certain instant of time is delivered to an external entity. For such an implementation the measurement system 100 may further comprise a communication interface 140 comprising necessary hardware and software for implementing a selected communication technology. The applied communication technology may be wired, or wireless based and the communication interface 140 is implemented accordingly. Due to the application environment the wireless communication may be preferred because it gives more freedom in a positioning of the system, or at least the measurement portion of it, in an applicable position in order to monitor the elevator shaft. The applied wireless communication technology is advantageously selected so that it consumes little power especially in the implementation in which the measurement system 100 is powered with a battery. In some example embodiments the communication interface 140 may be used for transmitting further data in addition to the information on the indication wherein the further data may comprise the original measurement data in a raw form or processed in a predetermined manner obtained from the sensing elements 115. Hence, the external entity may be configured to perform analysis to the received data. Depending on the implementation the external entity may be another control unit, or device, residing locally in the site the measurement system 100 is implemented to. Such other control unit may e.g. comprise more computing power and resources to conduct more detailed analysis to the data received from the measurement system 100. Alternatively or in addition, at least part of the data may be delivered to a remotely locating entity, such as to a data centre, for further use.

For sake of clarity, it is worthwhile to mention that the local control unit 120 may be implemented with at least one processor (denoted with uP in Figure 1 ) and with at least one memory (denoted with M in Figure 1 ). The at least one memory M may store computer program code (denoted with SW in Figure 1 ). By executing at least portion of the computer program code the at least one processor causes the local control unit 120 to cause an operation of the measurement system 100 as is described herein. The operation may at least comprise obtaining the measurement data from the sensing elements 115 as well as processing of the data so as to generate the indication descriptive on a presence of a predefined object in the monitored space.

Reverting back to the foregoing teaching describing that a second portion of the sensing elements 115 may be shielded from the radiation at least in part. Such an arrangement may be implemented for filtering out an effect caused by internal self-heating of the thermal sensor unit by using the measurement data obtained from the second portion of the sensing elements 115 in an evaluation of the measurement data obtained from the first portion of the sensing elements 115. In other words, the data obtained from the second portion of the sensing elements 115 is considered to represent the internal heating of the thermal sensor unit 110 which needs to be removed from the measurement data of the first portion of the sensing elements 115 in order to improve accuracy of the measurement, and, thus, the detecting a presence of the predefined object(s).

The measurement system 100 may be installed in various positions in an elevator system in order to monitor the elevator shaft. Thus, some aspects of the invention may relate to an elevator system. An example of a portion of the elevator system 200 is schematically illustrated in Figure 2. The elevator system 200 according to the present invention comprises an elevator shaft 210 and at least one measurement system 100 as described in the foregoing description. In the elevator shaft 210 one or more elevator cars 220 may be arranged to travel wherein the elevator car 220 may be connected to a counter-weight 230 over a traction sheave in a known manner. As derivable from Figure 2 the measurement system 100 may be installed to a various positions wherein the elevator car 220; a pit of the elevator shaft 210 (the pit area is referred with 240 in Figure 2); a top part of the elevator shaft 210 (the top part is referred with 250 in Figure 2); a counter-weight 230 are ones of the most efficient positions for the installation. As it comes to the elevator car 220 an optimal position for installing the measurement system 100 may be on top of the elevator car 220, e.g. on roof, but alternatively or in addition the measurement system 100 may be installed at a bottom of the elevator car 220. Correspondingly, the measurement system 100 may be installed on top of the counter-weight 230, but naturally it is possible to mount at the bottom of the counter-weight 230. There may also be executed coordination in the installation positions of the measurement system 100 to the elevator car 220 and to the counter-weight 230, but also with respect to the other positions, so that monitoring can be achieved throughout the elevator shaft 210. Figure 2 also illustrates schematically a person as the object 270 under monitoring.

Some further aspects of the present invention relate to a method for monitoring a presence of a predefined object 270 in an elevator shaft 210. An example of the method is shown in Figure 3. In step 310, measurement data is received from a thermal sensor unit 110 implemented with a plurality of sensing elements 115 in a form of floating vacuum thermal transistors, TMOS, positioned to generate measurement data from the elevator shaft 210. Moreover, in step 320 it is generated, by a local control unit 120 associated to with the thermal sensor unit 110, an indication on the presence of the predefined object 270 on a basis of the measurement data received from the thermal sensor unit 110.

In accordance with the invention the indication may indicate one of the following: the predefined object 270 is present in the elevator shaft 210; the predefined object 270 is non-present in the elevator shaft 210.

The method may further comprise, prior to generating 320 the indication, a step of filtering out an effect caused by internal self-heating of the thermal sensor unit 110 by using the measurement data obtained from a second portion of the sensing elements 115 of the thermal sensor unit 110 in an evaluation of the measurement data obtained from a first portion of the sensing elements 115 of the thermal sensor unit 110.

As derivable from above, some aspects of the present invention may relate to a computer program which, when executed by at least one processor, such as a processor of the local control unit 120, cause an apparatus, such as the measurement system 100 to perform at least some portions of the method as described. For example, the computer program may comprise at least one computer-readable non-transitory medium having the computer program code stored thereon. 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 may comprise a proprietary application, such as computer program code for performing the monitoring a presence of a predefined object in an elevator shaft 210.

The present invention provides a solution for arranging a monitoring of an elevator shaft 210 in a cost-efficient manner. Moreover, the invention applying the measurement system 100 as defined provides a solution for generating information on a possible presence of the object 270 in the elevator shaft 210 in an accurate manner and also so that both stationary and moving objects 270 may be detected. A still further advantage is a low consumption of electrical energy by the measurement system 100 which enables supply of the electrical energy in the measurement system 100 from a battery 130 which, in turn, gives freedom in positioning the measurement system 100 in desired positions in the elevator system 200 in an easy way. Hence, the use of the measurement system 100 as defined in the elevator system 200 provides a plurality of advantages over the known solutions.

The specific examples provided in the description given above should not be construed as limiting the applicability and/or the interpretation of the appended claims. Lists and groups of examples provided in the description given above are not exhaustive unless otherwise explicitly stated.