Patent Publication Number: US-2015073748-A1

Title: Method and system for measuring traffic flow in a building

Description:
This application is a continuation of PCT International Application No. PCT/EP2012/062490 which has an International filing date of Jun. 27, 2012, the entire contents of which are incorporated herein by reference. 
    
    
     The present invention refers to the determination of traffic flow in the people mover system of a building. Such a people mover system may comprise escalators and/or elevators which are intended to convey passengers and/or goods to their destination in an area, particularly in a building. 
     Such data is important for the optimization of the people mover system, particularly in course of the renovation or replacement of an existing people mover system. The retrieved data about traffic flow can be for example input to a call allocation system of the people mover control so as to optimize per se well known targets in call allocation, e. g. minimization of travelling time or waiting time or optimization of the energy use or maximization of the traffic flow in total. 
     Accordingly, the object of the present invention is to create a method and system for retrieving traffic flow data in a building with minor effort. According to the invention this object is solved with the features of claims  1  and  11 . Preferred embodiments of the invention are subject matter of the corresponding dependent claims. 
     For retrieving traffic flow data monitoring units are temporarily located in the area. Generally, the term “area” stands for any area which may comprise one or several buildings as e.g. a fair location or an airport. Anyway, the term area also may indicate one single building of a part thereof. Hereinafter the term “building” is used as a specific example of an area whereby it shall be understood that the invention may always be applied to larger or smaller areas as well. 
     First, it has to be mentioned that monitoring units are installed temporarily in the building, which means that they are installed only for a time period (monitoring period) which is necessary to retrieve the necessary event data to establish traffic flow information of an area. This may be a few days, one or several weeks or—e.g. in case of large areas with changing traffic as e.g. fairs—one or several months. 
     The temporary installation also means that the monitoring units are mounted at the entrance/exit areas of a people mover system such that they can easily be removed. They can for example be mounted to the entrance exit areas with bolts, with magnet tapes or adhesive tapes. In an elevator system e.g. each monitoring unit is mounted detachably at a car wall or ceiling. The monitoring unit can be mounted with a magnetic plate or with an adhesive tape or with small bolts which do not hamper the appearance of the mounting base after the monitoring unit is detached. By these measures it is ensured that the appearance of the people mover system is not impaired when the monitoring units are removed after the monitoring period. 
     Preferably, a monitoring unit is placed in locations of the building which are adapted to contribute relevant information for the general traffic flow data. Generally, it is assumed that reliable information about traffic flow is obtained when at each entrance and/or exit area of the people mover system a monitoring unit is located, whereby an entrance area can be also an exit area (e.g. an elevator car door area). By this means it is possible to monitor the complete traffic in the people mover system of the area. In an elevator system these areas are preferably the landing doors of each floor and of each elevator. Additionally the entrance lobby of the building may be monitored, if desired. 
     The monitoring units may use currently known types of sensors for monitoring an area on the movement or existence of persons or goods, as e.g. cameras, IR-sensors, optical sensors. 
     The monitoring unit comprises at least one sensor which is able to determine whether or not a passenger has entered an elevator car or an escalator entrance/exit area or whether or not a car door has opened etc. Preferably, this event data is taken or processed into a textual event. With the term “textual event” a data format is meant which does not comprise graphical data but only data about whether or not an event has happened and possibly what kind of event has happened (entrance or exit of a passenger, number of passengers). This is important as graphical data comprises large data volumes which are to be handled and transmitted. The transmission of large data volumes is troublesome so that preferably the event data is processed into textual data already in the monitoring unit, before any transmission of said data may occur. Even if cameras are used as sensors the graphic information obtained by the cameras is preferably immediately processed into textual data. On this behalf the monitoring unit preferably comprises a microprocessor for the immediate processing of the graphic signals of the camera into textual data. 
     The event data may comprise all data relating to any traceable changes in the car interior as passenger entering/leaving the car, door-to-open time, door-to-close time etc. All these parameters can be handled as a corresponding event, e.g. “passenger-entering event”, “passenger-leaving event”, “car-empty event”, “car-full event”, “door-open event”, “door-close event”. Accordingly, the event-data may comprise different parameters—preferably in addition to the time and location of the occurrence of the corresponding event. 
     With camera based-sensors it is further possible to track each passenger when he/she enters and when he/she exits the area monitored by the camera-based sensor, as based on camera data an adapted tracking software is able to detect and trace a passenger as one separate entity apart from others. Hereby it is possible to identify for example the departure floor and destination floor of each passenger. If data of several camera-based sensors are combined (in the recording/processing unit), it is for example possible to identity the whole track of each passenger from the entrance door to the destination floor. This enables the elevator builder to exactly adapt the new people mover system to the detailed needs of the persons in the building. 
     The information taken by the sensors of the monitoring units can be processed in different ways. One alternative is to provide the monitoring units with a wireless communication link which communication link is able to communicate with a corresponding communication link of a reporting unit. The reporting unit is able to record and process all the events communicated from the different monitoring units. In this connection the recording unit and/or the monitoring units preferably have a clock so that the events communicated by the different monitoring units can be correlated to the event time. 
     Preferably each monitoring unit transmits an individual ID to the recording unit—or transmits on a different carrier frequency—which enables the recording unit to correlate the transmitted event data and the event time data to the event location data—the location of the transmitting monitoring unit—which provides a sufficient data set for establishing the traffic flow information for the monitored area via the events caught with the sensors of the monitoring units. The ID can be added to the event data or may be transmitted as separate data in conjunction with the event data. 
     In this connection it is only relevant that the recording unit gathers the event data and all correlated data as event time and event location whereas the processing of the traffic flow from these data can be performed in the recording unit or later on in a separate processing unit. 
     The computed traffic flow can be used later for the control of the people mover system in said area, either during the optimization of an existing control or during a renovation of the people mover system with a modern control system. 
     In case at least one of said monitoring units is located in an elevator car preferably an acceleration sensor or magnetometer is used in said monitoring unit to obtain event location data of the elevator car. In this case it is possible that the monitoring unit does not only provide data about the elevator car in which the monitoring unit is located but also at which stop floor the events happening in entrance/exit area of the elevator car take place. By this means it is not necessary to provide monitoring units at each landing door of each floor of a building. 
     If the monitoring units comprise its own clock for the establishment of the event time data preferably the clocks of all monitoring units are synchronized at the beginning of the monitoring phase. By this measure it can ensured that the event time data taken by the different monitoring units are in synchronization. 
     In very crowded lobbies for example in base floors or ground floors it can be necessary to provide for the monitoring period a fence arrangement which guides the passengers to the entrance/exit area one by one which better enables the monitoring units to catch each passenger separately. This measure therefore increases the reliability and the accuracy of the events caught by the sensors. 
     In a preferred embodiment of the invention it is possible to work without any communication links in the monitoring units if the monitoring units comprise a memory which is detachable. Such a memory can preferably be an SD-card or a USB-stick. In this case preferably the monitoring unit comprises a clock and when the event data and the event time data provided by the clock is stored in a memory also the ID of the monitoring unit is stored together with the event data on the memory card so that it is possible to track the location of the monitoring unit when the data is processed later on, e. g. after the monitoring period. This arrangement is very economic as no efforts for data transmission have to be taken during the monitoring period. Also in this case the monitoring unit may comprise an acceleration sensor or a magnetometer. Then position data from the acceleration sensor or magnetometer can be stored on the detachable memory so that the complete data set with event data, event time and event location is available for processing. 
     A magnetometer is a preferable means to obtain information about the floor of the elevator on which the event data has been established. Thus, at the beginning of the monitoring period at least one test run is made with the elevator car driving from the uppermost to the lowermost floor. Hereby the magnetometer takes up an individual magnetic reference profile of the over the complete shaft height. During the monitoring period the actual car position can always be exactly derived by comparing the current magnetometer data with the magnetic reference profile. 
     It is also possible to provide each monitoring unit with a memory as well as with a communication link. In this case the memory must not be detachable because in this case the stored data can be read out during the monitoring period or afterwards with a reading device communicating with the communication link of the monitoring unit which reading devices can be connected to the recording units to further process the event, event time and event location data. The communication link can be wireless or wire-based. 
     The power supply of the monitoring unit is preferably a battery or an accumulator which keeps the monitoring unit independent of the power supply of the people mover system. 
     Preferably the computed traffic flow data is later on used in a call allocation algorithm of the control of the people mover system, e. g. in an elevator group control. 
     The above mentioned embodiments may be combined with each other arbitrarily as long as there are no technical contradictions occurring in such combination. 
    
    
     
       The invention will be described hereinafter with the aid of the schematic drawing. In this drawing: 
         FIG. 1  shows schematic illustration diagram of an elevator group with three elevators, 
         FIG. 2  shows a diagram of an elevator car comprising a monitoring unit, and 
         FIG. 3  shows a diagram of the components located in a monitoring unit. 
     
    
    
       FIG. 1  shows an elevator group  10  having an elevator shaft  12  in which two passenger elevator cars  14 ,  16  are moving vertically. These passenger cars are configured for passenger transport. Further one load elevator  18  is located in the elevator shaft  12 , which load elevator  18  is configured to transport large groups of passenger or bulky and/or heavy loads. In each of these elevator cars  14 ,  16 ,  18  a monitoring unit  20  is provided having a sensor which scans the car door area. Each monitoring unit  20  communicates wirelessly with a recording unit  22  located at an adapted space in the elevator shaft  12 , preferably on its bottom. 
     The monitoring unit  20  comprises a sensor for scanning the door area, a wireless communication link for the communication with the recording unit  22  as well as an acceleration sensor or magnetometer for obtaining information about the vertical position (floor) of the respective elevator car  14 ,  16 ,  18  in the elevator shaft  12 . 
     Furthermore, each monitoring unit  20  of the cars  14 ,  16 ,  18  preferably transmits a unique ID to the recording unit  22  which is then able to differentiate the incoming signals from the three different monitoring units  20  of the elevator cars  14 ,  16 ,  18 . 
     With that information the recording unit  22  obtains event data from the sensors of the monitoring units  20  as well as event location data via the ID of the monitoring unit as well as the position data retrieved from the acceleration sensor or magnetometer. 
     The monitoring units  20  and/or the recording unit  22  comprises a clock so that each event caught by the sensor of the monitoring units  20  is immediately correlated to the current event time which allows the recording unit to specify the events in time as well as location. 
       FIG. 2  shows an elevator car  14 ,  16 ,  18  of  FIG. 1  in more detail. The elevator car has a car bottom  24  and a car ceiling  26  as well as side walls  28 . In one of the side walls  28  a car door area  30  is provided which is monitored by the monitoring unit  20 . The monitoring unit  20  comprises a casing  32  from which an objective lens  34  of a camera of the monitoring unit  20  protrudes in the direction of the car door  30 . The casing  32  has a magnetic bottom plate  36  so that the monitoring unit  20  can be fastened without any effort to the metal ceiling  26  of the elevator car. 
     A more detailed diagram of the monitoring unit  20  is shown in  FIG. 3 . Accordingly, the monitoring unit  20  comprises a control unit  38  to which a camera  40  with an objective lens  34  is coupled. Furthermore, the monitoring unit  20  comprises its own power supply, preferably an accumulator  44 . Furthermore, the control unit  38  is connected with a wireless communication link  46  for the communication with a recording unit  22  or with a hand-held device for reading out event data stored in a memory unit  48  to which the control unit  38  of the monitoring unit  20  is connected. The memory unit  48  preferably comprises changeable memory devices, such as SD-cards  50  or other types of flash memories. Finally the control unit  38  of the monitoring unit  20  is connected with an acceleration sensor  52 , e. g. a magnetometer to track the position of the elevator car in the elevator shaft. 
     Such kind of monitoring unit  20  is able to store each event data obtained by the camera  40  correlated with the event time obtained by an internal clock of the control unit  38  and with the event location data obtained by an internal ID which is e.g. written into a ROM of the control unit  38  and via the data from the acceleration sensor or magnetometer  52 . 
     In this arrangement the monitoring unit  20  the control unit  38  comprises a microprocessor and is thus able to process the graphic event data of the camera into textual data and to store the correlated event, event time and event location data on the SD-card  50 . Alternatively, the control unit  38  is able to communicate via the communication link  46  with the recording unit  22  to send each event data together with any kind of event location data, as e. g. the monitoring unit ID and information from the acceleration sensor or magnetometer  52 . In this case no memory would be necessary in addition to the RAM of the control unit  38 . 
     The monitoring unit  20  of  FIG. 3  is on the other side able to track and catch all events in said elevator car without any interaction with external devices, e. g. without any interaction with the recording unit  22 . 
     After the end of the monitoring period the SD-card  50  of all monitoring units can be collected and written out by a recording or processing unit. In this recording or processing unit all the necessary calculations can be made for retrieving traffic flow information from the event data, event time data and event location data of all monitoring units  20 . This recording or processing unit can be e.g. located at the elevator company. 
     In case the monitoring unit  20  is only intended for direct interaction with the recording unit  22  it does not need an internal memory  48 ,  50 . On the other hand, if all the event data is to be stored on the memory  48  in connection with the SD-card  50  and to be processed after the monitoring period no communication link  46  is required. The provision of both features enable the operation of the monitoring unit  20  according to the preferred of the above mentioned operation alternatives. 
     The sensor does not need to be a camera  40  with an objective  42  but may also be an infrared sensor or other per se known monitoring sensor for people detection. 
     The memory  48  can also be flash memory or a memory working in connection with USB-sticks and other changeable media which are per se known. 
     The invention is not limited to the embodiment but can be varied within the scope of the enclosed claims.