Monitoring device and method for determining operating health of pressure medium operated device

Abstract

A monitoring device and a method for determining operating health of a pressure medium operated device. The monitoring device is configured for processing input measuring data relating to operation of the pressure medium operated device. An operating condition value is determined in the monitoring device, where after the operating condition value is compared to an input reference data in order to determine current operating health. The reference data is determined by utilizing strength analysis, which is executed for a design model of the associated pressure medium operated device.

Claims

1. A monitoring device for determining operating health of a pressure medium operated device, which includes a frame having plural pressure spaces and a cylinder space that includes a piston that moves linearly based on a pressure difference between the pressure spaces, the monitoring device comprising: one or more first sensors arranged to measure pressure from the plurality of pressure spaces; one or more second sensors arranged in the cylinder space to measure at least an amount of movement of the piston; one or more third sensors arranged in the cylinder space to measure a mechanical load of the pressure medium operated device; mounting means for fastening the monitoring device to the frame of the pressure medium operated device; at least one reference data input to the monitoring device, the reference data including one or more reference pressures of the plural pressure spaces, a reference positon of the piston, and a reference mechanical load; and wherein: the monitoring device having one or more processors configured to: store, in a memory device, a plurality of sets of predetermined features, each set of predetermined features identifying an operating style of an operator; receive measuring data from the one or more first, second, and third sensors, the measuring data including at least pressure measurement, piston movement measurements, and mechanical load measurements, the measuring data relates to at least one physical feature of the pressure medium operated device during operation of the pressure medium operated device; filter the received measuring data according to one of a plurality of predetermined control strategies including failure, fatigue, and service schedule, which are indicative of the operating health of the pressure medium operated device, the pressure, piston movement, and mechanical load measuring data being filtered into at least two categories having different importance for the operating health of the pressure medium operated device according to the one predetermined control strategy; process the filtered measuring data for determining at least one operating condition value of a current situation, wherein only one of the at least two categories of the filtered measuring data is used for determining the at least one operating condition value; analyze the filtered measuring data to determine the operating style of a current operator of the pressure medium operated device by identifying one of the sets of predetermined features associated with the determined operating style in the filtered measuring data; classify a use of the pressure medium operated device being monitored based on the one set of predetermined features identified in the filtered measuring data; calculate input reference data using at least a fatigue analysis executed for a design model of the pressure medium operated device; compare the operating condition value with the calculated input reference data in order to determine an operating health of the pressure medium operated device; and generate a warning signal or message including an estimated period of time to failure based on the operating health and the classified use of the pressure medium operated device.

2. The device as claimed in claim 1, wherein the monitoring device comprises: at least one processor for executing at least one monitoring program in the processor and is configured to process the received measuring data to obtain the operating condition value and perform the comparison with the calculated input reference data.

3. The device as claimed in claim 2, wherein the one or more processors is configured to determine the reference data by FE-analysis (Finite Element Analysis).

4. The device as claimed in claim 3, wherein the one or more processors of the at least one monitoring device is configured to determine the operating health of the monitored pressure medium operated device by monitoring an operating life of at least one single component of the monitored pressure medium operated device.

5. The device as claimed in claim 4, wherein the one or more processors determines at least one fatigue limit by performing the fatigue analysis.

6. The device as claimed in claim 5, wherein the input reference data includes a maximum total amount of operating cycles defined for an associated pressure medium operated device or a critical single component of the pressure medium operated device.

7. The device as claimed in claim 2, wherein the pressure medium operated device being monitored is a hydraulic cylinder.

8. The device as claimed in claim 1, wherein the processor is configured to determine the reference data by FE-analysis (Finite Element Analysis).

9. The device as claimed in claim 1, wherein the monitoring device is configured to determine the operating health of the monitored pressure medium operated device based on an operating life of at least one single-component of the monitored pressure medium operated device.

10. The device as claimed in claim 1, wherein the input reference data is determined by fatigue analysis and includes at least one fatigue limit.

11. The device as claimed in claim 1, wherein the at least one reference data input includes a maximum total amount of operating cycles defined for an associated pressure medium operated or a single component of the pressure medium operated device.

12. The device as claimed in claim 1, wherein the pressure medium operated device being monitored is a hydraulic cylinder.

13. The device as claimed in claim 1, wherein the monitoring device is located at the pressure medium operated device being monitored.

14. The device as claimed in claim 1, wherein the monitoring device is located external to the pressure medium operated device being monitored.

15. The device as claimed in claim 1, wherein the one or more second sensors is further arranged in the cylinder space to measure at least a number of operation cycles of the pressure medium operated device.

16. The device as claimed in claim 1, wherein the one or more second sensors is further arranged in the cylinder space to measure movement in seals of the cylinder space.

17. A method for determining operating health of a pressure medium operated device, which includes a frame having plural pressure spaces and a cylinder space that includes a piston that moves linearly based on a pressure difference between the pressure spaces, the monitoring device being mounted to the frame of the pressure medium operated device, the method comprising: measuring, by one or more first sensors arranged in proximity to the plurality of pressure spaces, pressure in at least one of the plurality of pressure spaces; measuring, by one or more second sensors arranged in the cylinder space, at least an amount of movement of the piston; measuring, by one or more third sensors arranged in the cylinder space, a mechanical load of the pressure medium operated device; storing, in a memory device, a plurality of sets of predetermined features, each set of predetermined features identifying an operating style of an operator; receiving, by one or more processors of the at least one monitoring device, measuring data from the one or more first, second, and third sensors, the measuring data including at least pressure measurement, piston movement measurements, and mechanical load measurements, the measuring data relates to at least one physical feature of the pressure medium operated device during operation of the pressure medium operated device; filtering, via the one or more processors of the at least one monitoring device, the received measuring data according to a predetermined control strategy, including failure, fatigue, and service schedule, which are indicative of the operating health of the pressure medium operated device, the pressure, piston movement, and mechanical load measuring data being filtered into at least two categories having different importance for the operating health of the pressure medium operating device, and the filtered measuring data identifying one or more operating cycles according to an effect on importance for the operating health of the pressure medium operated device according to the one predetermined control strategy; determining, via the one or more processors of the at least one monitoring device, at least one operating condition value based on the filtered measuring data, wherein only one of the at least two categories of the filtered measuring data is used for determining the at least one operating condition value; inputting reference data to the one or more processors of the at least one monitoring device; analyzing, via the one or more processors of the at least one monitoring device, the filtered measuring data to determine the operating style of a current operator of the pressure medium operated device during the operation being monitored by identifying one of the sets of predetermined features associated with the determined operating style in the filtered measuring data; classifying, via the one or more processors of the at least one monitoring device, a use of the pressure medium operated device being monitored based on the one set of predetermined features associated with the determined operating style identified in the filtered measuring data; calculating, via the one or more processors of the at least one monitoring device, input reference data using at least a fatigue analysis executed for a design model of the pressure medium operated device; comparing, via the one or more processors of the monitoring device, the operating condition value with the calculated input reference data in order to determine the operating health of the pressure medium operated device; and generating, via the one or more processors of the monitoring device, a warning signal or message including an estimated period of time to failure based on the operating health and the classified use of the pressure medium operated device.

18. The method according to claim 17, comprising comparing the calculated input reference data computed on the basis of the design model, before inputting to the monitoring device, to results of experimental laboratory tests made in a test stand; and adjusting the calculated reference data based on the comparison.

19. The method as claimed in claim 17, further comprising: measuring at least a number of operation cycles of the pressure medium operated device by the one or more second sensors.

20. The method as claimed in claim 17, further comprising: measuring movement in seals of the cylinder space by the one or more second sensors.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Some embodiments are described in more detail in the accompanying drawings, in which

(2) FIG. 1 is a schematic diagram of a monitoring system,

(3) FIG. 2 is a schematic diagram of processing measuring data,

(4) FIG. 3 is schematic side view of a hydraulic device provided with a monitoring device, and

(5) FIG. 4 is a schematic side view of another monitoring system, wherein a hydraulic device is provided with measuring devices and is being monitored by means of an external monitoring device.

(6) For the sake of clarity, the figures show some embodiments of the disclosed solution in a simplified manner. In the figures, like reference numerals identify like elements.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

(7) FIG. 1 shows a system for monitoring operating health of a hydraulic device 1, which may be a hydraulic actuator such as a hydraulic cylinder or hydraulic motor. Further, the hydraulic device may be a hydraulic pump or hydraulic accumulator, for example. The hydraulic device 1 is provided with one or more measuring devices 2 for measuring one or more physical features during the use of the hydraulic device 1. The gathered and produced measuring data 3 is input to a monitoring device 4 by means of input means 5. The monitoring device 4 may be located in connection with the monitored hydraulic device 1, or it may be located external to the hydraulic device 1. The monitoring device 4 may comprise one or more processors 6 for executing one or more monitoring programs 7. The monitoring device 4 may also comprise a filtering program or other type of filtering means 8 in order to determine significance of the input measuring data 3. Alternatively, the measuring device 2 may be provided with suitable filtering means, whereby the measuring data 3, which is input to the monitoring device 4, is already filtered and is classified to be relevant.

(8) Further, at least one reference data 9 is also input to the monitoring device 2 by means of input means 5. The reference data 9 may comprise one or more reference values 9a or a set of several numerical values, or alternatively, or in addition to, one or more reference model 9b, which may be a mathematical model or algorithm. The reference data 9 may be determined already during the design process of the monitored hydraulic device 1. In order to determine the reference data 9 only design data or model 10 of the hydraulic device 1 is needed. The reference data 9 may be generated by executing strength analysis 11 for the design data. Typically a strength analysis program and computer are utilized.

(9) The monitoring device 4 may analyse the input measuring data 3 and may process an operating condition value 12, which indicates current situation of the hydraulic device 1. The operating condition value 12 may indicate cumulated loading, wearing or operating cycles, for example. In order to determine operating health of the hydraulic device 1 the monitoring device 2 compares 13 the determined current operating condition value 12 with the input reference data 9 and indicates the current operating health 14 of the hydraulic device 1. The produced operating health 14 may indicate remaining operating cycles or mechanical loadings, or it may indicate degree of wear, for example. The monitoring device 4 may also comprise a display device 15 or other means for indicating the operating health 14 for service personnel. Alternatively, or in addition to the display device 15 the monitoring device 4 may comprise a data communication device 16 for allowing a data connection between the monitoring device 4 and at least one external device. Thus, the operating health 14 may be indicated visually, or it may be transmitted to a portable terminal device, for example.

(10) FIG. 2 illustrates that the measuring data may be filtered so that only significant measuring results are taken into account when determining operating health of a hydraulic device.

(11) As it is shown in FIG. 3, the hydraulic device 1 may be a hydraulic cylinder. The hydraulic cylinder comprises a frame 17 inside which is at least one pressure space 18a, 18b, which is connected by means of feed means to a hydraulic system 19. The hydraulic cylinder further comprise a piston 20 arranged inside a cylinder space of the frame 17 and is sealed by means of seals 21 against an inner surface of the cylinder space. The piston 20 is arranged to move linearly according to pressure difference between the pressure spaces 18a, 18b. Generated linear movement may be transmitted by means of a piston rod 22 to a desired use.

(12) The hydraulic cylinder may be provided with one or more measuring devices. Pressure sensors 2a or transducers may be arranged in connection with pressure ducts leading to the pressure spaces 18a, 18b, or pressure sensing devices may be arranged to measure pressure directly from the pressure spaces 18a, 18b. Measuring data of the pressure sensors 2a may be used to determine pressures of the pressure spaces and caused mechanical loadings to the construction. The hydraulic cylinder may also comprise one or more position measuring devices 2b, whereby number of operating cycles of the hydraulic cylinder may be detected as well as amount of movement of the piston 20 and the seals 21. The operating cycles may also be recognized by analysing the pressure data and pressure variations. Mechanical loading of the hydraulic cylinder may also be measured by means of one or more load sensors 2c such as strain gauges, piezoelectric sensors or any other type of sensor allowing measurements of mechanical loadings. In addition to the mentioned sensors 2a-2c other type of measuring devices may be used to measure physical features of the hydraulic cylinder. The measuring data may be transmitted from the sensors 2a-2c to a monitoring device 4 mounted to the hydraulic cylinder. Alternatively, one or more sensors may be integrated to the monitoring device whereby they may form a module.

(13) The monitoring device 4 may comprise mounting means 23 for fastening the monitoring device 4 on an outer surface of the frame 17 of the hydraulic cylinder. The mounting means 23 may comprise fast coupling means allowing easy mounting and dismounting of the monitoring device 4. The monitoring device may comprise a body consisting of two halves or several body parts, which may be placed on an outer surface of a hydraulic cylinder and which halves or body parts are connectable to each other by fastening means, such as screws. Alternatively, the mounting means 23 may comprise a fastening band, which may be placed around the frame 17 of the hydraulic cylinder. The mounting means 23 may be designed so that mounting to existing hydraulic devices is easy and requires no modifications to their basic construction. The monitoring device 4 may be positioned so that an indicating device 15 is visible. The monitoring device 4 may transmit the monitoring data and results by means of a data communication unit 16 to an electrical terminal device 24 or to a data network comprising one or more servers or computers.

(14) In FIG. 3 the measuring data may be transmitted from the measuring devices 2a-2c through wired or wireless data transmission to the monitoring device 4. Further, the data communication between the monitoring device 4 and the external devices 24 may also be wired or wireless. The wireless data communication means may utilize Bluetooth, radio signals, WiFi or RFID, for example.

(15) FIG. 4 discloses another monitoring device 4, which is located external to a hydraulic device 1 feeing monitored. The hydraulic device 1 may correspond to the hydraulic cylinder or FIG. 3 and may be provided with one or more several measuring devices 2a-2c. Measuring data of the measuring devices 2a-2c may be transmitted to a data communication device 16, which may transmit the data to the external monitoring device 4. Alternatively, the measuring devices 2a-2c may be provided with data transmission means of their own, whereby measuring data may be transmitted directly from the measuring devices 2a-2c to the monitoring device 4. The data communication may be wired or wireless. The wireless data communication means may utilize Bluetooth, radio signals, WiFi or RFID, for example. Transmission of the measuring data may be done periodically, continuously or according to a separate request.

(16) In FIG. 4 the monitoring device 4 may be a mobile electrical terminal device such as a laptop, tablet computer, smart phone, for example. Alternatively the monitoring device is a server or set or several servers or computers. The monitoring device may also be based on a cloud service. The monitoring device 4 may transmit the monitoring data and results to an electrical terminal device 24 or to a data network comprising one or more servers or computers.

(17) Alternatively, the monitored device disclosed above may be a device operable by means of pressurized gas or other suitable fluid.

(18) The disclosed monitoring and the determined operating health may be utilized at least in the following manner: a) to record load history of a monitored device, b) to determine or estimate number of load cycles to failure of a monitored component, c) to define a preventive maintenance schedule for the device being monitored, d) to provide an estimation of remaining operating life of the pressure medium operated actuator or a specific monitored component i.e. to estimate lifespan, e) to indicate exceed of the predetermined fatigue limit, f) to identify deterioration of a specific component, and g) to predict time to service and the extend of service required.

(19) The drawings and the related description are only intended to illustrate the idea of the invention. In its details, the invention may vary within the scope of the claims.