HK1111670A - Condition monitoring system - Google Patents

Description

Condition monitoring system

Technical Field

The present invention relates to elevator systems. More particularly, the present invention relates to a system for monitoring the operating conditions of an elevator.

Background

Elevator systems are electromechanical combinations of devices that include many movable and rotating parts that are subject to wear and failure during operation of the elevator system. Also, during long periods of operation of the elevator system, the actuators (actuators) controlling the movable and rotating parts, as well as the electronic components and sensors connected to said actuators, are subject to wear and failure. A fault may also be caused by unexpected external factors, such as e.g. a violent impact against the elevator door, or the consequence of damage to the elevator. It is, however, of primary importance for the operation of an elevator system that the elevator system should work safely and correctly in all operating situations in the first place. Therefore, the elevator system is maintained regularly to ensure safe operation and sufficient ride comfort. If the elevator is not maintained in time, the elevator may malfunction such that passengers cannot use the elevator at all or the operation quality of the elevator is significantly deteriorated. Before an actual failure, the elevator may become noisy, the elevator car may have an annoying sway, the stopping accuracy of the elevator car may deteriorate upon landing, or some other corresponding characteristic of the elevator operation may be impaired, indicating a future failure in advance. The scheduling of elevator maintenance has traditionally been achieved via regular maintenance according to fixed schedule based scheduling, and/or based on the density of elevator operation (operation history). The density of the operation is again dependent on the installation location of the elevator, resulting in individual demands regarding maintenance schedules. If the need for maintenance is not detected until one of the actuators controlling the operation of the elevator suddenly fails and prevents the preparation of the elevator, this may lead to a repair recommendation by the customer, resulting in an extra cost to the party responsible for the operation of the elevator. One way of eliminating or at least reducing the number of unscheduled maintenance visits is to equip the elevator with a condition monitoring system. The function of the condition monitoring system is to observe the operation of the elevator and to generate a parameter indicative of its operating condition, on the basis of which the current operating condition of the elevator can be estimated and its future operating condition predicted, so that the need for preventive maintenance can be planned. The condition monitoring system is usually connected to signals representing the operation of the elevator, on the basis of which the system calculates parameters describing the operating conditions of the elevator. A trend of change or a sufficiently large deviation of the parameter with respect to a defined reference value generates a specific warning about a sharp or predictable failure. The warning information is usually sent from the condition monitoring system to a maintenance center in charge of maintenance of the elevator system, where decisions are made regarding the required maintenance operations and their scheduling. For example, the system disclosed in U.S. Pat. No. 4,512,442 to Moore et al keeps counting how many times a door has been opened and closed and sends the count to a maintenance center for maintenance scheduling. The scheduling based on the operation density can be made more accurately by considering the type of the building. Some more advanced prior art systems additionally use the operational history data of the elevator for condition monitoring.

The prior art condition monitoring systems have considerable disadvantages and drawbacks. The signals representing the operation of the elevator are often difficult to obtain, which is why it is difficult and time-consuming to install and connect a condition monitoring system to the elevator system. Some of the signals required in condition monitoring may be located at a long distance from each other, e.g. in the control panel in the elevator machine room, while some other signals are located in the elevator car. In this case, it is necessary to have an additional car cable between the elevator car and the machine room to provide the required wiring of the signals to the condition monitoring system, involving a drastic increase in installation costs and time. In prior-art solutions, making a connection to the signal to be measured usually requires a galvanic (galvanic) connection between the condition monitoring system and the elevator control system and also often changes the cabling in the elevator, causing unnecessary installation work and additional costs. This current connection method involves the risk of causing disturbances in the operation of the elevator system signals for condition monitoring, thus creating a safety hazard. For this reason, elevators often have to be approved by supervising elevator safety authorities after installation of the condition monitoring system to check the operation of the safety equipment.

Further problems with prior art solutions are: elevator systems differ significantly from each other in electrical and functional aspects. The condition monitoring system has to take into account, among other things, the current and voltage levels of the signals used in the elevator being monitored, the timing of the signals and other elevator-specific circumstances. Condition monitoring systems implemented according to prior art are therefore generally applicable only in connection with certain elevator types, and it may not be possible to install them in old elevators, or the required installation, modification and configuration work may become a significant cost factor.

OBJECT OF THE INVENTION

The object of the present invention is to overcome some of the above-mentioned drawbacks and deficiencies encountered in prior-art solutions and to achieve a completely new type of solution for monitoring the condition of elevators. It is a further object of the present invention to achieve one or more of the following objectives:

a condition monitoring system which can be easily and quickly installed in new elevators and existing elevators,

-installation without additional car cables,

-automatically determining threshold values and setting parameters in connection with the operation and/or test run of the elevator,

reduction of damage to improve safety of travel,

-improving the comfort of the ride and,

storing data about the elevator system for later use, e.g. in preparing trend analysis to provide more accurate information about the operating conditions.

Disclosure of Invention

The condition monitoring system of the invention is characterized by what is disclosed in the characterization part of claim 1. Other embodiments of the invention are characterized by what is disclosed in the other claims. Inventive embodiments are also presented in the description part and drawings of the present application. The inventive content disclosed in the application can also be defined in other ways than is done in the claims. The inventive content may also consist of several separate inventions, especially if the invention is considered in the light of explicit or implicit sub-tasks or with respect to advantages or sets of advantages achieved. In this case, some of the attributes contained in the claims below may be superfluous from the point of view of separate inventive concepts. Within the framework of the basic idea of the invention, features of different embodiments of the invention can be applied in conjunction with other embodiments.

The following are definitions of the meanings of certain terms used in the text:

-maintenance needs: defining the actions of repairing the detected faults and/or quality defects and their urgency.

-elevator operation data: including information about the use of the elevator, the trip completed by the elevator, and/or other corresponding circumstances associated with the operation of the elevator over a known period of time;

-an elevator drive machine: including the equipment needed to move the elevator car in the hoistway (draft). The apparatus comprises: a drive motor, a set of hoisting ropes, a motor brake (brake) or motor brakes for preventing movement of the car, guide rails and guide grooves (guide shoe) for guiding the elevator car in the elevator shaft;

-threshold and setting parameters: the term refers to all of these parameters: settings, tolerance values and measurement reference values, which are determined based on a separate installation or some other corresponding context, and which can be configured in the condition monitoring system. The threshold values and setting parameters are used to observe changes in the derived and/or resulting quantities to detect fault conditions and/or the need for preventive maintenance.

The invention relates to an elevator condition monitoring system comprising at least one control unit and a sensor arrangement connected to the control unit. The elevator comprises: an elevator car, an elevator drive machine and a control system including a required safety circuit and a brake. According to the invention, the control unit of the condition monitoring system and the sensor arrangement connected to the control unit are fitted in conjunction with the elevator car and the sensor arrangement comprises at least a sensor measuring the current of the elevator safety circuit, which sensor is galvanically separated from the elevator safety circuit (galvanoshelly) and is connected to the safety circuit without interfering with the safety circuit wiring. The control unit and the sensor arrangement are preferably mounted on the roof of the elevator car.

In an embodiment of the invention, the sensor arrangement connected to the control system comprises, in addition to the sensor measuring the safety circuit current, one or more of the following sensors:

-an acceleration sensor as a means for measuring the acceleration of the car door;

-a current sensor as a means of measuring the current of the door operator motor;

-an acceleration sensor as a means for measuring the acceleration of the elevator car;

-a microphone as a means of measuring elevator door noise and/or elevator travel noise;

-a current sensor as a means of measuring the current of the elevator car lighting;

-a proximity sensor as a detector of the door zone and the door zone edge; and

a temperature sensor as a means of measuring the temperature of the elevator car and/or the elevator shaft,

one or more of the aforementioned sensors are galvanically separated from the control system of the elevator.

In an embodiment of the invention, the condition monitoring system generates one or more of the following derived quantities:

-a gate noise component during gate operation;

-a travel noise component when the elevator is moving between floors;

-a door motion component during door operation;

-door status data;

-a door motor current component during door operation;

-a car motion component when the elevator moves between floors;

-elevator car status data;

-safety circuit status data;

-stopping accuracy of the elevator car at landing; and

-current component of the cabin lighting.

In an embodiment of the invention, using derived quantities, the condition monitoring system determines one or more outcome quantities indicative of:

-operating conditions of cabin lighting; and/or

-operating conditions of the door machine; and/or

-operating conditions of the elevator drive machine; and/or

-an operating condition of the safety circuit; and/or

-the performance of the elevator; and/or

-the operating history of the elevator.

In an embodiment of the invention, the condition monitoring system comprises a memory device for storing the derived quantity and/or the resulting quantity for later use.

In an embodiment of the invention the condition monitoring system comprises a data transmission connection for transmitting the derived quantity and/or the resulting quantity and/or an alarm indicating the operating condition of the elevator to the remote monitoring system.

In an embodiment of the invention, the condition monitoring system has been installed to transmit information stored on the memory device to the remote monitoring system at a predetermined point in time.

In an embodiment of the invention, the condition monitoring system comprises a memory device having one or more derived quantity thresholds stored thereon for detecting a fault condition and/or for preventing the need for maintenance.

In an embodiment of the invention, one or more threshold values and/or setting parameters have been determined by performing at least one test run of the elevator.

In an embodiment of the invention, the condition monitoring system has been installed to determine threshold values and/or setting parameters based on statistical and/or other corresponding analysis.

The condition monitoring system of the invention has several advantages compared to prior art solutions. The condition monitoring system is easy and quick to install because its control unit and the sensors connected thereto are placed in conjunction with the elevator car. No additional car cables are required between the elevator car and the elevator control system in order to connect the sensors. The sensors required in condition monitoring are also easy to install as retrofit in conjunction with the elevator car, since they are almost freely selectable in conjunction with the placement of the elevator car and the existing cables of the elevator car do not have to be modified. The system of the invention does not pose a safety risk for the operation of the elevator system when it uses sensors galvanically separated from the control unit of the elevator system. In particular making a connection to the safety circuit of the elevator system involves no problems because the connection does not form a galvanic connection between the condition monitoring system and the elevator safety circuit and does not require interrupting the safety circuit (e.g. disconnecting the safety circuit conductor from the connector), thus also avoiding additional checks by authorities after installation of the system. To allow faster installation, the configuration of the system can be performed automatically. Using the system of the invention it is also possible to collect information about the use of the elevator system and to measure the performance of the elevator system. The data produced by the system can be communicated to a remote maintenance system for statistical preparation and other corresponding analysis relating to, for example, the operational condition, use and/or performance of the elevator system.

Drawings

Fig. 1 presents an arrangement according to the invention in an elevator system;

FIG. 2 shows a block diagram of the system of the present invention; and

fig. 3 shows the elevator safety circuit connection.

Detailed Description

Fig. 1 presents by way of example an arrangement according to the invention in an elevator system. Reference numeral 100 denotes an elevator car, which includes a car door 102 and a door operator 103 that controls opening and closing of the car door 102. At the top of the elevator car is placed a control unit 104 of a condition monitoring system, which measures and analyses signals indicative of the operating conditions of the elevator via a sensor arrangement (not shown in fig. 1) mounted in connection with the car. In the hoistway 107, the elevator car is moved between floors A, B and C by drive machine 109. Each floor level is provided with a landing door 12 which, together with the car door, is opened and closed when the elevator car is at said landing. An elevator control system 110 is placed in the machine room 108, from where the control system communicates with the elevator car via a car cable 111 for transmitting the required control signals and power between the elevator car and the elevator control system. The elevator control system also comprises several actuators, such as e.g. elevator call panels and display units and cables (not shown in fig. 1) connecting these.

Fig. 2 shows, by way of example, a block diagram of a condition monitoring system of the present invention. The control unit 104 of the condition monitoring system is for example a computer unit equipped with a processor, a memory and required interfaces and software. The control unit comprises a signal receiving and processing unit 200, wherein signals 250 measured from the elevator system are received and processed to produce derived quantities. Derived quantities in this context refer to quantities derived from the measurement signal 250 used in the monitoring of the operating conditions of the elevator, such as e.g. the effective value, the frequency spectrum, the divergence (or mean value) of the signal, or some other corresponding quantity reflecting the behavior of the signal, as well as to status data of the system or actuator to be monitored that can be determined on the basis of the measured signal. The derived quantities generated are transmitted to the analysis unit 220. At least some of the derived quantities generated are stored on the memory device 210 for later utilization. The function of the analysis unit is to observe the operating conditions of the elevator on the basis of the derived quantities produced and to produce specific warnings about detected defects and preventive maintenance needs to be communicated to the remote monitoring system 272 of the maintenance center 270. In order to estimate the operating conditions, the memory device 230 of the analysis unit comprises several threshold values and setting parameters and if the signal still remains below or exceeds the threshold values or setting parameters, an alarm is generated regarding the need for malfunction or preventive maintenance. The aforementioned threshold values and other required setting parameters are e.g. determined by performing one or more test runs of the elevator, in conjunction with a commissioning (committing) of the elevator system, or are formed from statistical properties of said quantities and derived quantities during normal operation. Reference numeral 240 indicates a data transfer means for forming a data transfer connection 280 between the control unit 104 and the remote supervision system 272. The data transmission connection may be any data transmission connection applicable for this purpose, preferably a wireless data transmission connection.

In fig. 2, reference numeral 260 denotes a device for measuring the current I flowing in the elevator safety circuit_safetyThe current sensor of (1). The safety circuit of an elevator typically consists of safety contacts and switches, which are connected in series in the circuit 300 presented in fig. 3. SC310 represents the static circuit of the safety circuit, while switch CD315 represents the car door switch and switch nld 320 represents the landing door switch. N is the number of floor levels depending on how many floors the elevator comprises. The switch MC340 corresponds to a main contactor (main contactor) of the elevator. Total current I of safety circuit_safetyDetermined by the states of the switches SC, CD, LD and MC and the corresponding partial currents i1, i2, i3 and i 4. Thus, the condition monitoring system can be based on the total current I_safetyThe state of the safety circuit is inferred at each moment. Table 1 below includes definitions of possible states of the safety circuit as shown in fig. 3:

safety circuit current at point P	State of the switch	Safety circuitFunctional state of
			i＝0	SC is 0, CD is not visible, MC is 0	The static circuit is opened, the door state is invisible, and the main contactor is powered off
i＝i1	SC is 0, CD is 0, LD is invisible, MC is 0	Static circuit switch, open carriage door, invisible landing door, power failure of main contactor
			i＝i1+i2	SC＝0，CD＝1，LD＝0，MC＝0	Static circuit switch, carriage door switch, landing door open, main contactor power off
i＝i1+i2+i3	SC＝1，CD＝1，LD＝1，MC＝0	Static circuit, carriage door and landing door, main contactor cut-off
			i＝i1+i2+i3+i4	SC＝1，CD＝1，LD＝1，MC＝1	Static circuit, carriage door and landing door, main contactor being energized

TABLE 1

By determining the state of the safety circuit in the manner described above in different operating situations of the elevator, the condition monitoring system is able to determine the operating state of the elevator safety circuit and the actuators affecting the state of the safety circuit.

The car door, landing door and door operator mounted on the car form a door mechanical system, the condition of which depends on the acceleration a attached to the car door leaf for measuring the horizontal movement of the door leaf_doorIs monitored by the acceleration sensor. In order to obtain a more accurate determination of the operating condition of the door mechanical system, it is also possible to measure the door leaf acceleration perpendicular to the aforementioned movement. Acceleration a_doorAs a means of observing the motion components of the door leaf during door operation, such as for example the instantaneous acceleration, velocity, position and/or vibration spectrum of the door leaf. From the door leaf movement component, door state data (states and their mutual timing) can also be deduced. The possible gate states are: closed, opening, open, closing, reopening, nudging. In the solution illustrated in fig. 2, the door operator current I_ddorAs measured by current sensor 263. The motor current indicates the torque of the motor and thus the force (e.g., friction) resisting the opening and closing of the door. Changes in the door motion component and/or changes in the current of the door operator motor and/or changes in the status data indicate wear or soiling (soil) and/or electrical or mechanical failure of the door mechanical system. The condition of the door mechanical system can also be determined by means of a microphone 264 mounted on the elevator car by analyzing the noise N generated during door operation_carSpectrum monitoring. An increase in the noise amplitude at the considered frequency is indicative of a change occurring in the door mechanical system, such as for example wear. In order to monitor the condition of the drive machine of an elevator, the elevator is provided with a device mounted on the car for measuring the vertical acceleration a of the elevator car_carThe acceleration sensor 62. In order to obtain a more accurate determination of the operating conditions, the acceleration of the car perpendicular to the vertical movement may also be measured. The vertical direction movement component of the elevator car, such as e.g. the position in the elevator shaft, the instantaneous acceleration, the velocity and/or the vibration spectrum, is derived from the acceleration a by known mathematical methods_carAnd (4) calculating. From the car motion component, car state data may also be inferred. The car state may be one of the following: stationary (standing), accelerating, constant speed, decelerating, slowing (cruise), re-leveling(leveling). Changes in the motion components and/or condition data of the elevator car indicate wear, soiling and/or electrical or mechanical failure of the drive machine. The condition of the drive machine can also be determined by means of the microphone 264 mounted on the elevator car by analysing the noise N generated during the various states of elevator operation_carIs monitored. An increase in the noise amplitude at the considered frequency indicates a change occurring in the drive machine, such as, for example, wear.

The condition of the drive machine can also be monitored by means of door zone sensors 266 mounted on the elevator car. The sensor detects the detection range (field) of the reference entry/exit sensor installed at each floor level when the elevator is moving in the elevator shaft. Detecting data P by combining door zone references_dzoneAnd from the acceleration a of the elevator car_carThe derived position data allows to determine the exact stopping distance of the elevator car with respect to the detected reference edge, thus monitoring the stopping accuracy of the elevator car at different landings. A change in the stopping accuracy of the car indicates a change in the elevator drive machine, such as e.g. the brake of the drive machine.

In fig. 2, reference numeral 267 indicates a device for measuring the internal and/or external temperature T of the elevator car_carThe temperature sensor of (1). The respective values indicative of the amount of operation of the drive machine may change, for example, as a result of a change in the viscosity (viscocity) of the lubricant of the drive machine when the temperature changes. By taking into account the temperature T prevailing in the elevator car and/or in the elevator shaft_carThe (inquiry) changes in question can be compensated for, thus improving the accuracy of the quantity indicating the operating condition of the elevator. The temperature measurement can also be used for monitoring the operating conditions of a possible air conditioning system of the elevator car and/or for detecting a fire occurring in the building.

To monitor the lighting of the elevator car, the condition monitoring system measures the current I consumed by the lighting by means of the current sensor 264_light. When the illumination current decreases relative to the reference value of the current, the number of defective light sources can be inferred. If the current becomes in a jump or jump,this indicates a future failure of the light source.

In addition to the above-mentioned data associated with condition monitoring of elevators, the system also produces information concerning the use and performance of the elevators. Using the measured signals and the status data derived from the signals, the number of activities and the number of actions of the various actuators comprised in the elevator can be determined, such as e.g. the number of door operations, the duration of the door operation phases, the number of departures and stops of the elevator at each floor, the number of travels of the elevator between different floors. The system is thus able to generate information for calculating the performance and the operating history of the elevator.

The data collected on the memory device 210 is transferred from the control unit to the remote monitoring system 105 over the data transmission connection 106 during a period of a defined time interval. The data received in the remote monitoring system are stored in a database 271, where the data can be further used for calculation, statistical analysis of the run density of the elevator (operation history of the elevator) and/or the performance of the elevator.

The sensor arrangement 250 is made up of several sensors, one or more of which are galvanically separated from the elevator control system. The elevator car must be equipped (retrofit) with sensors unless it is already equipped with sensors ready to be connected to a remote monitoring system. "sensor" also refers to a measurement point (e.g., a connector) that is already present in conjunction with the elevator car and to which the condition monitoring system can be directly connected through the connector. In this case the sensor producing the signal to be measured can also be placed elsewhere in the elevator system than in the elevator car, wherein the sensor signal has been wired as an implementation comprised in the elevator system. The current sensor for current measurement is, for example, an inductance-based iron core sensor, the core structure of which can be opened in order to allow threading (thread) of the current conductor to be monitored into the channel formed by the sensor core without damaging the conductor. In combination with these sensors, it is advantageous to compensate the frequency response and/or the temperature drift (cruise) of the sensors by using suitable compensation connections to improve the measured acceleration and the measurement accuracy. For detecting the door area reference, the elevator car is equipped with a proximity sensor (proximity sensor)266, which may be any contactless proximity sensor suitable for the purpose, such as e.g. an inductive, optical or capacitive proximity sensor. The proximity sensor identifies a reference, such as a bar-shaped object made of magnetic material or a luminous elongated sticker (packer), mounted at each landing.

In order to determine the setting parameters and thresholds used by the condition monitoring system, one or more test runs are performed on the elevator after installation of the system. Based on the information collected during the test run, the condition monitoring system automatically determines at least some threshold and/or set parameter values. During operation of the elevator system, the condition monitoring system collects data about the elevator system and updates the aforementioned values with known statistical methods. The condition monitoring system is therefore self-learning and is able to adapt itself automatically to changing conditions.

In the case of an elevator system having multi-deck elevators in which two or more elevator cars have been installed in the same car frame, one or more condition monitoring systems are installed to monitor the operating conditions of the elevators.

It will be apparent to those skilled in the art that: the invention is not limited to the embodiments described above, in which the invention has been described by way of example, but different embodiments of the invention are possible within the scope of the inventive concept defined in the claims.

Claims (10)

1. A system for condition monitoring of an elevator, which system comprises at least a control unit 104 and a sensor arrangement 250 connected to the control unit 104, and which elevator comprises an elevator car 100, an elevator drive machine 109 and an elevator control system 110 comprising the required safety circuit and brakes, characterized in that the control unit 104 of the system and the sensor arrangement 250 connected to the control unit have been installed in connection with the elevator car, and that the sensor arrangement 250 comprises at least a sensor 260, which measures the current of the safety circuit and is galvanically separated from the elevator safety circuit and connected to the safety circuit 300 without interfering with the safety circuit wiring.

2. The system according to the preceding claim, characterized in that the sensor arrangement 250 comprises, in addition to the safety circuit sensor 260, one or more of the following sensors:

an acceleration sensor 261 as a device that measures the acceleration of the door 102;

a current sensor 263 as a device for measuring the motor current of the door operator 103;

an acceleration sensor 262 as a device that measures the acceleration of the elevator car 100;

a microphone 265 as a device for measuring the door noise of the elevator and/or the travel noise of the elevator;

a current sensor 264 as a means of measuring the lighting current of the elevator car;

proximity sensors 266 as detectors of the door zone and the door zone edges; and

a temperature sensor 267 as a means of measuring the temperature of the elevator car 100 and/or the temperature of the hoistway 107,

one or more of the aforementioned sensors are clearly separated from the control system of the elevator.

3. A system according to any of claims 1 to 2, characterized in that the system generates one or more of the following derived quantities:

-a gate noise component during gate operation;

-a travel noise component when the elevator is moving between floors;

-a door motion component during door operation;

-door status data;

-a door motor current component during door operation;

-a car motion component when the elevator moves between floors;

-elevator car status data;

-safety circuit status data;

-stopping accuracy of the elevator car at landing; and

-current component of the cabin lighting.

4. A system according to any one of claims 1 to 3, characterized in that using derived quantities, the system calculates one or more resulting quantities indicative of:

-operating conditions of cabin lighting; and/or

-an operational condition of the door mechanical system; and/or

-operating conditions of the elevator drive machine; and/or

-the operating condition of the safety circuit of the elevator; and/or

-the performance of the elevator; and/or

-the operating history of the elevator.

5. A system according to any of claims 1 to 4, characterized in that the system further comprises a memory device 210 for storing derived quantities and/or resulting quantities for later use.

6. System according to any of claims 1-5, characterized in that the system further comprises a data transmission connection 106 for transmitting derived quantities and/or result quantities and/or warnings indicating the operating conditions of the elevator to a remote monitoring system.

7. The system of claim 6, wherein: the condition monitoring system has been installed to transmit the information stored on the memory device 210 to the remote monitoring system 272 at a predetermined point in time.

8. A system according to any one of claims 1 to 7, characterized in that the system further comprises a memory device 230 on which one or more threshold values and/or setting parameters for detecting a fault situation, and/or for preventing maintenance needs, are stored.

9. System according to any one of claims 1-8, characterized in that one or more threshold values and/or setting parameters have been determined by performing at least one test run of the elevator.

10. System according to any of claims 1 to 9, characterized in that the system has been installed for determining threshold values and/or setting parameters on the basis of statistical and/or other corresponding analyses.