Fault detection device for a hydraulic system

Abstract

The present embodiments relate to a fault detection device (200) for a hydraulic system (100), a hydraulic system (10) capable of detecting a fault and a method of operating a fault detection device (200). The fault detection device (200) comprises a monitoring and fault detection unit (240) receiving first and second pressure values from a first pressure sensor (210) and a second pressure sensor (220); and a fault detection unit (260) detecting a fault of at least one hydraulically operated device (130) when one of a plurality of pairs (341, 342, 343, 344, 345) is within a first predetermined tolerance range (310) of relative pressure values and outside a second predetermined tolerance range (320), and wherein the fault detection unit (260) detects a fault of a pump (160) when one of the plurality of pairs is outside the first predetermined tolerance range (310) of relative pressure values.

Description

TECHNICAL FIELD

[0001] The present embodiments relate to a fault detection device, and more particularly to a fault detection device for a hydraulic system. Embodiments of the invention also relate to a hydraulic system capable of detecting a fault with such a fault detection device, and to a method of operating such a fault detection device to detect a fault in a hydraulic system. BACKGROUND

[0002] In many technical applications using hydraulic power as their primary or backup power source, it is of utmost importance for safety and economic reasons that the required hydraulic power has the highest possible level of reliability.

[0003] Therefore, the health of a hydraulic system is usually observed by monitoring different parameters including pressure, leakage, temperature, vibration, etc. Changes in one or more of these parameters usually indicate a developing fault in the associated hydraulic system.

[0004] Generally, known fault detection devices for hydraulic systems define a health identifier from the monitored parameters. In addition to the measured and processed parameters, such a health identifier is usually composed of calculated and / or simulated parameters.

[0005] During operation of a hydraulic system, conventional fault detection devices usually observe such a health identifier using a dedicated monitoring algorithm for detecting a developing fault in the hydraulic system. In some applications, the monitoring algorithm is implemented as software in the hydraulic system to enable online real-time fault monitoring. Alternatively, the monitoring algorithm is implemented as remote software for offline post-operation analysis.

[0006] Common methods for monitoring a hydraulic system for fault detection purposes include, for example, US 2017 / 0184138 A1, DE 10 2008 035 954 A1, EP 1 674 365 A1, DE 103 34 817 A1, EP 1 988 287 B1, FR 3087 887 B1, JP 4 542 819 B2, US 5,563,351 A, US 8,437,922 B2, US2021088058 and WO2013 / 063262 A1.

[0007] However, the above-mentioned methods for monitoring a hydraulic system all use dependencies between different types of parameters to define an identifier of the health of the hydraulic system. The above-mentioned methods also often rely on extremely complex measuring devices.

[0008] Document US 7,082,758 B2 describes a hydraulic machine in which a hydraulic pump failure is detected and the pump lifetime is estimated before the pump failure occurs. The discharge pressure, the oil temperature and the discharge filter differential pressure are measured, the correlation between the filter differential pressure and the discharge pressure is determined and a representative filter differential pressure is calculated from this correlation. Using the oil temperature - differential pressure correlation function, the representative differential pressure value is corrected so that the variable component caused by the oil temperature is eliminated therefrom. The long term trend and the short term trend of the corrected differential pressure increase over time are calculated. The pump failure is predicted or the pump lifetime is estimated based on the degree of deviation between the long term trend and the short term trend.

[0009] However, the described method requires the presence of a filter to measure the discharge filter differential pressure. Moreover, the definition of the indicator of the hydraulic pump health is determined by a linear correlation with the data measured on-line, i.e. during the operation of the hydraulic system. This correlation is then used to define the representative differential pressure. The representative differential pressure is then monitored over time and compared with a predetermined differential pressure. In other words, the differential pressure is the health indicator. In addition, the described method detects only the failure of the hydraulic pump, but not the failure of the associated hydraulic system. Moreover, the described method requires a temperature sensor to determine the oil temperature. SUMMARY

[0010] Therefore, it is a first object to provide a new failure detection device for a hydraulic system. The new failure detection device should be able to detect the failure of the hydraulic pump and the failure of the associated hydraulic system. Moreover, the new failure detection device should be able to distinguish between the failure of the hydraulic pump and the failure of the associated hydraulic system. Furthermore, it is a second object to provide a new hydraulic system capable of detecting a failure, which comprises such a new failure detection device, and a third object to provide a method of operating such a new failure detection device.

[0011] The first object is achieved by a failure detection device for a hydraulic system, comprising the features as claimed in claim 1.

[0012] More specifically, a fault detection apparatus for a hydraulic system, comprising: a first pressure sensor that senses a first pressure value of hydraulic fluid in a supply line; a second pressure sensor that senses a second pressure value of hydraulic fluid in a tank drain line; and a monitoring and fault detection unit that receives the first and second pressure values from the first and second pressure sensors and that comprises a monitoring unit that monitors the first and second pressure values from the first and second pressure sensors during operation of a plurality of hydraulically operated devices, and a fault detection unit that memorizes a plurality of pairs of the first and second pressure values, wherein the fault detection unit detects a fault in at least one of the plurality of hydraulically operated devices when one of the plurality of pairs is within a first predetermined tolerance range of a relative pressure value and outside a second predetermined tolerance range of the relative pressure value, and wherein the fault detection unit detects a fault in the pump when the pair is outside the first predetermined tolerance range of the relative pressure value. The hydraulic system comprises: a tank containing hydraulic fluid; a plurality of hydraulically operated devices; a supply line; a pump that carries hydraulic fluid from the tank to the plurality of hydraulically operated devices via the supply line; and a tank drain line for pumping hydraulic fluid back to the tank from the pump.

[0013] As one example, the hydraulic system can comprise a variable displacement pump driven by an external mechanical source. The hydraulic pump can carry hydraulic fluid from the tank to a plurality of hydraulically operated devices (e.g., valves, actuators, and other consumers of hydraulic fluid) via a supply line, and back to the tank via a drain line. The first pressure sensor can be installed in the supply line (e.g., between a filter and the plurality of hydraulically operated devices).

[0014] The hydraulic pump can send hydraulic fluid back to the tank via a tank drain line. The second pressure sensor can be installed in the tank drain line.

[0015] The first software program can run on a computer that combines the signals of the first and second pressure sensors into a defined ratio by a first algorithm during a unique initial calibration before normal operation mode, before starting the hydraulic system.

[0016] Outside of this unique initial calibration, the second software program can calculate and memorize a reference curve based on supply pressure and tank drain pressure by a second algorithm. The reference curve comprises a safety region (also called a tolerance) that covers statistical scatter of measurements within an acceptable amplitude, and additional thresholds for accurately detecting degradation of the hydraulic system. Such a safety region and such thresholds are defined for predetermined parameters.

[0017] The third software program can calculate and memorize the pressure signals obtained during certain operating conditions of the hydraulic system in a normal operating mode into time-stamped pressure profiles by means of a third algorithm.

[0018] The fourth software program based on a fourth algorithm can compare the obtained pressure signals with the determined threshold value and indicate a deviation from the determined threshold value. If desired, the fourth software program can monitor the trend of the obtained pressure signals with respect to a reference curve.

[0019] The fifth software program based on a fifth algorithm can determine whether any deviation of the pressure profiles obtained during normal system operation originates from a fault of the hydraulic pump or a fault of the remaining hydraulic system components, for example by monitoring whether a measured point of a certain measured condition exceeds a threshold value around a predetermined tolerance of a reference curve.

[0020] The sixth software program based on a sixth algorithm can memorize the outputs of the fourth and fifth software programs and optionally inform an operator.

[0021] If desired, a temperature sensor can be connected to the tank to improve the robustness of monitoring temperature changes.

[0022] Thus, the number of pressure sensors is reduced to a minimum of two. In fact, in addition to the pressure sensor in the supply line, only one additional pressure sensor is required in the housing discharge line. The presence of a pressure sensor and a temperature sensor in the pressure supply line is considered to be given for most hydraulic systems.

[0023] The software programs feature several specific but not complex algorithms to process the pressure signals and enable the detection of the development of a fault in the hydraulic pump or the remaining hydraulic system components based on the concept of a damage indicating curve (DIC), which is sometimes also referred to as a fault-free operating curve.

[0024] In addition, the software programs allow a robust and reliable design of the health monitoring system that meets the safety operation and economic constraints. Moreover, due to its simple structure and robustness, the fault detection device can be used in real time and in post-processing applications for mobile and stationary hydraulic systems.

[0025] According to one aspect, the fault detection unit determines a trend based on a plurality of binary tuples, and wherein the fault detection unit detects at least one of a fault of at least one of the plurality of hydraulically operated devices and a fault of the pump based on the trend.

[0026] According to an aspect, the fault detection device further comprises a temperature sensor that senses a current temperature value of the hydraulic fluid in the tank and provides the current temperature value to the monitoring and fault detection unit, and wherein the fault detection unit adjusts the first predetermined tolerance range of the relative pressure value and the second predetermined tolerance range of the relative pressure value based on the current temperature value of the hydraulic fluid.

[0027] According to an aspect, the monitoring and fault detection unit further comprises a calibration unit that determines the first predetermined tolerance range of the relative pressure value and the second predetermined tolerance range of the relative pressure value based on the first pressure value and the second pressure value received from the first pressure sensor and the second pressure sensor during an initial calibration of the hydraulic system prior to operation of the plurality of hydraulically operated devices.

[0028] According to an aspect, the calibration unit determines the first predetermined tolerance range and the second predetermined tolerance range of the relative pressure value based on predetermined operating conditions of the pump.

[0029] According to an aspect, the monitoring and fault detection unit further comprises an output device that outputs at least one of the monitored first pressure value and the second pressure value of the hydraulic fluid, a detected fault of at least one of the plurality of hydraulically operated devices, or a detected fault of the pump.

[0030] Further, the second object is achieved by a hydraulic system capable of detecting a fault comprising the features of claim 7.

[0031] More specifically, a hydraulic system capable of detecting a fault comprises the above described fault detection device, and a hydraulic system comprising: a tank containing a hydraulic fluid; a plurality of hydraulically operated devices; a supply line; a pump that carries the hydraulic fluid from the tank to the plurality of hydraulically operated devices via the supply line; a return line for returning the hydraulic fluid from the plurality of hydraulically operated devices to the tank; and a housing drain line for returning the hydraulic fluid from the pump to the tank.

[0032] According to an aspect, the hydraulic system further comprises a filter located in the supply line between the pump and the plurality of hydraulically operated devices.

[0033] According to an aspect, the hydraulic system further comprises a drive mechanism that drives the pump.

[0034] Further, the third object is achieved by a method of operating the above described fault detection device comprising the features of claim 10.

[0035] More specifically, the method of the above described operational fault detection apparatus includes the operations of: sensing, with a first pressure sensor, a first pressure value of hydraulic fluid in a supply line; sensing, with a second pressure sensor, a second pressure value of hydraulic fluid in a housing drain line; receiving, with a monitoring and fault detection unit, the first and second pressure values from the first and second pressure sensors; monitoring, with a monitoring unit in the monitoring and fault detection unit, the first and second pressure values from the first and second pressure sensors when the hydraulic system is in a normal operating mode; memorizing, with a fault detection unit in the monitoring and fault detection unit, a plurality of pairs of the first and second pressure values in the normal operating mode; detecting, with the fault detection unit in the monitoring and fault detection unit, a fault of at least one of the plurality of hydraulically operated devices when one of the plurality of pairs is within a first predetermined tolerance range of the relative pressure values and outside a second predetermined tolerance range of the relative pressure values; and detecting, with the fault detection unit, a fault of the pump when said one of the plurality of pairs is outside the first predetermined tolerance range of the relative pressure values.

[0036] According to an aspect, the method further includes generating, with the monitoring and fault detection unit, a fault-free operation curve based on an extrapolation of the first and second pressure values received by the monitoring and fault detection unit when the hydraulic system is in a calibration mode.

[0037] According to an aspect, the method further includes determining, with the monitoring and fault detection unit, the first predetermined tolerance range of the relative pressure values and the second predetermined tolerance range of the relative pressure values based on the fault-free operation curve.

[0038] According to an aspect, the method further includes determining, with the monitoring and fault detection unit, a trend based on the plurality of pairs; and detecting at least one of the fault of at least one of the plurality of hydraulically operated devices and the fault of the pump based on the trend.

[0039] According to an aspect, the method further includes generating and providing statistics on the first and second pressure values of the hydraulic fluid based on the plurality of pairs at different time stamps.

[0040] According to an aspect, the method further includes notifying an operator of the hydraulic system of the detected fault in response to detecting the fault of at least one of the plurality of hydraulically operated devices or in response to detecting the fault of the pump. BRIEF DESCRIPTION OF DRAWINGS

[0041] The preferred embodiments are outlined in the following description with reference to the accompanying drawings, by way of example only. In the drawings, like or functionally similar components and elements are marked with the same reference numerals and characters, and are therefore described only once in the following description.

[0042] FIG. 1 is a diagram of an illustrative hydraulic system capable of detecting faults including a hydraulic system and a fault detection device according to some embodiments.

[0043] FIG. 2 is a diagram of an illustrative no-fault operation curve and associated predetermined tolerance range of relative pressure values of a hydraulic system according to some embodiments.

[0044] FIG. 3A is a diagram of an illustrative trend monitoring indicating a pump fault according to some embodiments.

[0045] FIG. 3B is a diagram of an illustrative trend monitoring indicating a device fault of a hydraulic operated device according to some embodiments.

[0046] FIG. 3C is a diagram of an illustrative trend monitoring indicating a device fault of a hydraulic operated device immediately followed by a pump fault according to some embodiments; and

[0047] FIG. 4 is a flowchart showing an illustrative operation of a fault detection device for operating a hydraulic system according to some embodiments. DETAILED DESCRIPTION

[0048] Exemplary embodiments of the fault detection device can be used with any hydraulic system. Examples of devices having a hydraulic system can include excavators, bulldozers, backhoes, log splitters, shovels, loaders, cranes, hydraulic brakes, power steering systems, automatic transmissions, garbage trucks, aircraft flight control systems, elevators, industrial machinery, etc.

[0049] FIG. 1 is a diagram of a hydraulic system 10 capable of detecting faults including a hydraulic system 100 and a fault detection device 200 coupled to the hydraulic system 100.

[0050] Illustratively, the hydraulic system 100 can include a tank 110. The tank 110 can be open and operate at atmospheric pressure. Alternatively, the tank 110 can be closed and pressurized.

[0051] The tank 110 can be filled with a hydraulic fluid 120. The hydraulic fluid 120 can be any fluid suitable for use in a hydraulic system. For example, the hydraulic fluid can be based on mineral oil and / or water.

[0052] For example, the hydraulic system can include a plurality of hydraulically operated devices 130. The hydraulically operated devices 130 can include hydraulic motors, hydraulic cylinders or other hydraulic actuators, control valves, pipes, hoses, and / or other consumptions of hydraulic fluid, to name a few.

[0053] The hydraulic system 100 can include a supply line 140 and a pump 160 that transports the hydraulic fluid 120 from the tank 110 to the plurality of hydraulically operated devices 130 via the supply line 140. If desired, the pump 160 can be implemented as a variable displacement type of piston pump. The pump 160 can supply the hydraulic fluid 120 to the hydraulically operated devices 130 at a given rate.

[0054] Illustratively, the hydraulic system 100 can include a drive mechanism 190. The drive mechanism 190 can drive the pump 160. If desired, the drive mechanism 190 can include an external mechanical actuator and / or an electric motor.

[0055] Illustratively, the hydraulic system 100 can include a return line 170 for returning the hydraulic fluid 120 from the plurality of hydraulically operated devices 130 to the tank 110, and a housing drain line 150 for returning the hydraulic fluid 120 from the pump 160 to the tank 110.

[0056] If desired, the hydraulic system 100 can include a filter 180. The filter 180 can be used to remove impurities from the hydraulic fluid 120. Illustratively, the filter 180 can be a high pressure filter located in the supply line 140. As one example, the filter 180 can be located in the supply line 140 between the pump 160 and the plurality of hydraulically operated devices 130.

[0057] Illustratively, the fault detection apparatus 200 can include a first pressure sensor 210 and a second pressure sensor 220. The first pressure sensor 210 can sense a first pressure value of the hydraulic fluid 120 in the supply line 140, and the second pressure sensor 220 can sense a second pressure value of the hydraulic fluid 120 in the housing drain line 150.

[0058] If desired, the fault detection apparatus 200 can include a temperature sensor 230. The temperature sensor 230 can sense a current temperature value of the hydraulic fluid 120 in the tank 110.

[0059] For example, the fault detection apparatus 200 can include a monitoring and fault detection unit 240. The monitoring and fault detection unit 240 can receive the first pressure value and the second pressure value from the first pressure sensor 210 and the second pressure sensor 220.

[0060] Illustratively, the monitoring and fault detection unit 240 can include a monitoring unit 250 and a fault detection unit 260. The monitoring unit 250 can monitor the first pressure values and the second pressure values from the first pressure sensor 210 and the second pressure sensor 220 during operation of the plurality of hydraulically operated devices 130.

[0061] For example, the fault detection unit 260 can memorize a plurality of pairs of the first pressure values and the second pressure values. When one of the plurality of pairs is within a first predetermined tolerance range of the relative pressure values and outside a second predetermined tolerance range of the relative pressure values, the fault detection unit 260 can detect a fault of at least one of the plurality of hydraulically operated devices 130. When the one of the plurality of pairs is outside the first predetermined tolerance range of the relative pressure values, the fault detection unit 260 can detect a fault of the pump 160.

[0062] Illustratively, the fault detection unit 260 can adjust the first predetermined tolerance range of the relative pressure values and the second predetermined tolerance range of the relative pressure values based on a current temperature value of the hydraulic fluid 120 measured by the temperature sensor 230.

[0063] If desired, the monitoring and fault detection unit 240 can include an output device 280. The output device 280 can output at least one of the following: the monitored first pressure values and the second pressure values of the hydraulic fluid 120, the detected fault of at least one of the plurality of hydraulically operated devices 130, or the detected fault of the pump 160.

[0064] As FIG. 1 illustrated, the monitoring and fault detection unit 240 can include a calibration unit 270. Prior to operation of the plurality of hydraulically operated devices 130, during an initial calibration of the hydraulic system 100, the calibration unit 270 can determine the first predetermined tolerance range of the relative pressure values and the second predetermined tolerance range of the relative pressure values based on the first pressure values and the second pressure values received from the first pressure sensor 210 and the second pressure sensor 220.

[0065] Illustratively, the calibration unit 270 can determine the first predetermined tolerance range and the second predetermined tolerance range of the relative pressure values based on predetermined operating conditions of the pump 160.

[0066] FIG. 2 is an illustrative fault-free operating curve 390 of a hydraulic system (e.g., the hydraulic system 100 of FIG. 1 ) and associated predetermined tolerance ranges 310, 320 of relative pressure values. During an initial calibration of the hydraulic system, the fault-free operating curve 390 can be determined using a calibration unit (e.g., the calibration unit 270 of FIG. 1 ).

[0067] Illustratively, during initial calibration of the hydraulic system, the calibration unit (e.g., the calibration unit 270 of the hydraulic system 100) can receive first and second pressure values of the hydraulic fluid in the supply line and the housing drain line from the first and second sensors, respectively. The first and second sensors can provide the first and second pressure values for a predetermined operating condition of the plurality of hydraulically operated devices and / or a predetermined operating condition of the pump during the initial calibration. FIG. 1

[0068] The calibration unit can define calibration points 330, 331, 332, 333, 334, 335 based on the first and second pressure values. The number of calibration points can depend on the number of predetermined operating conditions of the plurality of hydraulically operated devices and / or the number of predetermined operating conditions of the pump. Thus, there can be any number of calibration points. For simplicity and clarity, the number of calibration points has been limited to 6 in the example of FIG. 3. However, any number greater than 1 can be used if desired. FIG. 2

[0069] The calibration points 330, 331, 332, 333, 334, 335 can be represented in a two- dimensional Cartesian coordinate system 300 having the second pressure value of the hydraulic fluid 120 in the housing drain line 150 (i.e., measured by the second pressure sensor 220 of the hydraulic system 100) as the ordinate and the first pressure value of the hydraulic fluid 120 in the supply line 140 (i.e., measured by the first pressure sensor 210 of the hydraulic system 100) as the abscissa. Thus, the calibration points 330-335 are represented as a pair of supply pressure and housing pressure. FIG. 1 FIG. 1 The calibration points 330, 331, 332, 333, 334, 335 can be represented in a two- dimensional Cartesian coordinate system 300 having the second pressure value of the hydraulic fluid 120 in the housing drain line 150 (i.e., measured by the second pressure sensor 220 of the hydraulic system 100) as the ordinate and the first pressure value of the hydraulic fluid 120 in the supply line 140 (i.e., measured by the first pressure sensor 210 of the hydraulic system 100) as the abscissa. Thus, the calibration points 330-335 are represented as a pair of supply pressure and housing pressure.

[0070] Illustratively, the calibration unit can determine a fault-free operating curve 390 based on the calibration points 330-335. For example, the calibration unit can perform a regression analysis on the calibration points 330-335 to determine the fault-free operating curve 390.

[0071] As one example, the calibration unit can perform a linear regression to determine the fault-free operating curve 390 as having a linear dependence between the housing pressure 301 and the supply pressure 302. As another example, the calibration unit can perform a non-linear regression to determine the fault-free operating curve 390 as having a non-linear dependence between the housing pressure 301 and the supply pressure 302.

[0072] ​​​For example, the calibration unit can determine the first predetermined tolerance range 310 of relative pressure values and the second predetermined tolerance range 320 of relative pressure values based on first pressure values and second pressure values received from the first pressure sensor and the second pressure sensor during an initial calibration of the hydraulic system prior to operation of the plurality of hydraulically operated devices.

[0073] For example, the calibration unit can determine the first predetermined tolerance range 310 of relative pressure values and the second predetermined tolerance range 320 based on predetermined operating conditions of the pump and / or based on predetermined working conditions of the plurality of hydraulically operated devices.

[0074] As one example, the calibration unit can determine the first predetermined tolerance range 310 of relative pressure values as an absolute or relative distance from the fault-free operating curve 390. As another example, the calibration unit can determine the second predetermined tolerance range 320 of relative pressure values based on a minimum value and a maximum value on the fault-free operating curve 390 containing all calibration points.

[0075] If desired, the first predetermined tolerance range 310 of relative pressure values and the second predetermined tolerance range 320 can form a tube around the fault-free operating curve 390 in a two-dimensional Cartesian coordinate system 300 having a longitudinal coordinate of the housing pressure 301 and a transverse coordinate of the supply pressure 302. In scenarios where the calibration unit defines the fault-free operating curve 390 as a straight line (e.g., by linear regression), the first predetermined tolerance range 310 of relative pressure values and the second predetermined tolerance range 320 can form a rectangle in the two-dimensional Cartesian coordinate system 300.

[0076] During normal operation of the plurality of hydraulically operated devices, the monitoring and fault detection unit (e.g., FIG. 1 of the calibration unit 240) can receive first pressure values and second pressure values from the first pressure sensor and the second pressure sensor. For example, the monitoring and fault detection unit can receive first pressure values and second pressure values from the first pressure sensor and the second pressure sensor at different timestamps.

[0077] As one example, the monitoring and fault detection unit can receive a first pair 341 of first pressure values and second pressure values at a first timestamp, a second pair 342 of first pressure values and second pressure values at a second timestamp, a third pair 343 of first pressure values and second pressure values at a third timestamp, a fourth pair 344 of first pressure values and second pressure values at a fourth timestamp, a fifth pair 345 of first pressure values and second pressure values at a fifth timestamp, etc.

[0078] The monitoring and fault detection unit can include a monitoring unit that monitors the first pressure values and the second pressure values (e.g., FIG. 1The monitoring unit 250), and the fault detection unit (e.g., the monitoring unit 250) that stores multiple pairs of first and second pressure values ​​341, 342, 343, 344, 345. FIG. 1 (Fault detection unit 260).

[0079] When one of the multiple binary pairs 341, 342, 343, 344, and 345 is within a first predetermined tolerance range 310 of the relative pressure value and outside a second predetermined tolerance range 320 of the relative pressure value, the fault detection unit can detect a fault in at least one of the multiple hydraulically operated devices. When the binary pairs 341, 342, 343, 344, and 345 are outside the first predetermined tolerance range 310 of the relative pressure value, the fault detection unit can detect a pump fault.

[0080] like FIG. 2 As shown, all pairs 341 to 345 of the first and second pressure values ​​recorded during normal operation of the hydraulic system are within a first predetermined tolerance range 310 of the relative pressure values. Therefore, no pump failure in the hydraulic system was detected.

[0081] Similarly, FIG. 2 As shown, all pairs 341 to 345 of the first and second pressure values ​​recorded during normal operation of the hydraulic system are within the second predetermined tolerance range 320 of the relative pressure values. Therefore, no malfunction of the hydraulically operated equipment in the multiple hydraulically operated devices of the hydraulic system was detected.

[0082] Illustratively, fault detection devices (e.g., FIG. 1 The fault detection device 200 can determine the fault of one of the hydraulically operated devices and / or the pump by determining the trend of multiple binary pairs 341, 342, 343, 344, 345 over time.

[0083] FIG. 3A This is an illustrative trend chart indicating pump failure monitored by 350. (As shown...) FIG. 3A As shown, the fault detection unit (e.g., FIG. 1 The fault detection unit 260) stores 341 to 345 pairs of first and second pressure values ​​recorded at different timestamps during normal operation of the hydraulic system (e.g., a pair of supply pressure and housing pressure).

[0084] As an example, consider a scenario where a pair of first and second pressure values ​​is recorded over consecutive timestamps. In this scenario, the pairs 341 and 342 of the first two recorded first and second pressure values ​​are within a first predetermined tolerance range 310 and a second predetermined tolerance range 320 relative to the pressure values.

[0085] However, the consecutively recorded pairs 343, 344, 345 of first pressure values and second pressure values lie outside the first predetermined tolerance range 310 of relative pressure values and the second predetermined tolerance range 320 of relative pressure values. In fact, the fault detection unit can determine a trend 350 based on the plurality of pairs 341-345.

[0086] The trend 350 shows that the consecutively pairs 341-345 of first pressure values and second pressure values mainly point in a direction away from the no-fault operation curve 390. As FIG. 3A indicated, the casing pressure values increase proportionally compared to the supply pressure values. The trend 350 can indicate a pump fault, and thus the fault detection unit can detect a fault of the pump based on the trend 350.

[0087] FIG. 3B is a diagram of an illustrative trend monitoring 360 indicating a fault of a hydraulically operated device. As FIG. 3B indicated in the diagram, the fault detection unit (e.g., the fault detection unit 260 of FIG. 1 memorizes pairs 341-345 of first pressure values and second pressure values (e.g., pairs of supply pressure and casing pressure) recorded at different timestamps during normal operation of the hydraulic system.

[0088] As one example, consider a scenario in which pairs of first pressure values and second pressure values are recorded during consecutive timestamps. In this scenario, the first two recorded pairs 341 and 342 of first pressure values and second pressure values lie within the first predetermined tolerance range 310 and the second predetermined tolerance range 320 of relative pressure values.

[0089] However, the consecutively recorded pairs 343, 344, 345 of first pressure values and second pressure values lie within the first predetermined tolerance range 310 of relative pressure values and outside the second predetermined tolerance range 320 of relative pressure values. In fact, the fault detection unit can determine a trend 360 based on the plurality of pairs 341-345.

[0090] The trend 360 shows that the consecutively pairs 341-345 of first pressure values and second pressure values mainly point in a direction parallel to the no-fault operation curve 390. As FIG. 3B indicated, the casing pressure values increase proportionally compared to the supply pressure values in the same proportion as the pairs of the no-fault operation curve 390. The trend 360 can indicate a fault of a hydraulically operated device, and thus the fault detection unit can detect a fault of at least one of the plurality of hydraulically operated devices of the hydraulic system based on the trend 360.

[0091] FIG. 3Cis a graph indicative of an illustrative trend monitoring of a device fault of a hydraulic operation immediately followed by a pump fault. Illustratively, the fault detection unit (e.g., the fault detection unit 260 of FIG. 1 records pairs 341-345 of first and second pressure values (e.g., pairs of supply and case pressure) recorded at consecutive time stamps during normal operation of the hydraulic system.

[0092] As shown in FIG. 3C , the first recorded pair 341 of first and second pressure values lies within the first and second predetermined tolerance ranges 310, 320 of relative pressure values. At that time, no pump fault is detected, and no fault of at least one hydraulically operated device is detected.

[0093] However, the consecutively recorded pairs 342, 343, 344, 345 of first and second pressure values lie outside the first and / or second predetermined tolerance ranges 310, 320 of relative pressure values. In fact, the fault detection unit can determine a first trend 360 based on the plurality of pairs 341-343.

[0094] The first trend 360 shows that the consecutive pairs 341-343 of first and second pressure values are mainly directed in a direction parallel to the no-fault operation curve 390. As shown in FIG. 3C , the case pressure values increase at the same proportion as the pairs of the no-fault operation curve 390 compared to the supply pressure values. The first trend 360 can be indicative of a device fault of a hydraulic operation, and thus, the fault detection unit can detect a fault of at least one hydraulically operated device of the plurality of hydraulically operated devices of the hydraulic system based on the first trend 360.

[0095] Subsequently, the fault detection unit can determine a second trend 350 based on the pairs 343-345.

[0096] The second trend 350 shows that the consecutive pairs 343-345 of first and second pressure values are mainly directed in a direction away from the no-fault operation curve 390. As shown in FIG. 3C , the case pressure values increase, while the supply pressure values decrease. The trend 350 can be indicative of a pump fault, and thus, the fault detection unit can detect a fault of the pump based on the trend 350.

[0097] FIG. 4 is a flowchart 400 illustrating an illustrative operation for operating a fault detection apparatus (e.g., the fault detection apparatus 200). FIG. 1

[0098] During operation 410, the fault detection apparatus can sense, with a first pressure sensor, a first pressure value of a hydraulic fluid in a supply line.​

[0099] For example, FIG. 1 The first pressure sensor 210 of the fault detection device 200 can sense a first pressure value of the hydraulic fluid 120 in the supply line 140.

[0100] During operation 420, the fault detection device can sense, with the second pressure sensor, a second pressure value of the hydraulic fluid in the housing drain line.

[0101] For example, FIG. 1 The second pressure sensor 220 of the fault detection device 200 can sense a second pressure value of the hydraulic fluid 120 in the housing drain line 150.

[0102] During operation 430, the fault detection device can receive, with the monitoring and fault detection unit, the first pressure value and the second pressure value from the first pressure sensor and the second pressure sensor.

[0103] For example, FIG. 1 The monitoring and fault detection unit 240 in the fault detection device 200 can receive the first pressure value and the second pressure value from the first pressure sensor 210 and the second pressure sensor 220.

[0104] During operation 440, the fault detection device can monitor, with the monitoring unit of the monitoring and fault detection unit, the first pressure value and the second pressure value from the first pressure sensor and the second pressure sensor when the hydraulic system is in a normal operation mode.

[0105] For example, when the hydraulic system 100 is in a normal operation mode, FIG. 1 The monitoring unit 250 of the monitoring and fault detection unit 240 of the fault detection device 200 can monitor the first pressure value and the second pressure value from the first pressure sensor 210 and the second pressure sensor 220.

[0106] During operation 450, the fault detection device can memorize, with the fault detection unit of the monitoring and fault detection unit, a plurality of pairs of the first pressure value and the second pressure value in the normal operation mode.

[0107] For example, in the normal operation mode, FIG. 1 The fault detection unit 260 of the monitoring and fault detection unit 240 of the fault detection device 200 can memorize a plurality of pairs of the first pressure value and the second pressure value (e.g., pairs 341, 342, 343, 344, 345 of FIG. 2 to FIG. 3C ).

[0108] During operation 460, when one of the multiple pairs of pairs is within a first predetermined tolerance range of the relative pressure value and outside a second predetermined tolerance range of the relative pressure value, the fault detection device can use the fault detection unit of the monitoring and fault detection unit to detect a fault in at least one of the multiple hydraulically operated devices.

[0109] For example, when FIG. 2 to FIG. 3C When one of the multiple pairs 341, 342, 343, 344, and 345 is within a first predetermined tolerance range 310 of the relative pressure value and outside a second predetermined tolerance range 320 of the relative pressure value, FIG. 1 The fault detection unit 260 of the monitoring and fault detection unit 240 of the fault detection device 200 can detect faults in at least one of the multiple hydraulically operated devices 130.

[0110] During operation 470, when one of the multiple pairs is outside a first predetermined tolerance range of the relative pressure value, the fault detection device can use the fault detection unit to detect a pump fault.

[0111] For example, when FIG. 2 to FIG. 3C When the plurality of pairs 341, 342, 343, 344, and 345 are outside the first predetermined tolerance range 310 of the relative pressure value, FIG. 1 The fault detection unit 260 of the fault detection device 200 can detect faults in the pump 160.

[0112] After successful calibration in calibration mode, the hydraulic system can operate in normal operating mode. During calibration preparation, all components of the hydraulic system are verified for any defects.

[0113] Then, in response to verifying that there are no defects in the components of the hydraulic system, the fault detection device can use the monitoring unit of the monitoring and fault detection unit to monitor the first pressure value and the second pressure value from the first pressure sensor and the second pressure sensor, and use the fault detection unit of the monitoring and fault detection unit to memorize multiple pairs of the first pressure value and the second pressure value.

[0114] For example, FIG. 1 The monitoring unit 250 of the fault detection device 200 and the fault detection unit 240 can monitor the first pressure value and the second pressure value from the first pressure sensor 210 and the second pressure sensor 220, and FIG. 1 The fault detection unit 260 of the fault detection device 200 and the monitoring and fault detection unit 240 can memorize multiple pairs of first pressure values ​​and second pressure values ​​(e.g., FIG. 2 to FIG. 3C The pairs 341, 342, 343, 344, and 345.

[0115] Illustratively, the fault detection device can utilize a monitoring and fault detection unit to generate a fault-free operating curve (e.g., based on extrapolation of the first and second pressure values ​​received by the monitoring and fault detection unit when the hydraulic system is in calibration mode) based on multiple pairs of memorized first and second pressure values. FIG. 2 to FIG. 3C The fault-free operation curve 390).

[0116] For example, a fault detection device can use a monitoring and fault detection unit to determine a first predetermined tolerance range for the relative pressure value based on a fault-free operating curve (e.g., FIG. 2 to FIG. 3C The predetermined tolerance range 310 of the relative pressure value) and the second predetermined tolerance range of the relative pressure value (e.g., FIG. 2 to FIG. 3C The predetermined tolerance range for the relative pressure value is 320.

[0117] Illustratively, the fault detection device can utilize monitoring and fault detection units based on multiple binary pairs (e.g., FIG. 2 to FIG. 3C The pairs 341, 342, 343, 344, 345 are used to determine the trend (e.g., FIG. 2 to FIG. 3C The trend 350 and / or trend 360) and based on the trend, detect at least one of the faults of the hydraulically operated equipment and the pump in a plurality of hydraulically operated equipment.

[0118] For example, a fault detection device can be based on multiple tuples at different timestamps (e.g., FIG. 2 to FIG. 3C The tuples 341, 342, 343, 344, and 345 are used to generate and provide statistics on the first and second pressure values ​​of the hydraulic fluid.

[0119] Illustratively, the fault detection device may notify the operator of the hydraulic system of a detected fault in response to the detection of a fault in at least one of a plurality of hydraulically operated devices or in response to the detection of a pump fault.

[0120] It should be noted that modifications to the above embodiments are within the scope of common knowledge of those skilled in the art and are therefore also considered part of the present invention.

[0121] For example, FIG. 2 to FIG. 3C The predetermined tolerance range 310 of the relative pressure value is shown as having a constant distance from the fault-free operation curve 390. However, if desired, the predetermined tolerance range 310 of the relative pressure value may have a distance from the fault-free operation curve 390 that increases with increasing supply pressure and / or housing pressure.

[0122] Similarly,FIG. 2 to FIG. 3C The predetermined tolerance range 320 of the relative pressure value is shown as having a constant width independent of the housing pressure 301. However, if desired, the predetermined tolerance range 320 of the relative pressure value can increase in width as the housing pressure increases.

[0123] In addition, FIG. 2 to FIG. 3C The two-dimensional Cartesian coordinate system 300 shows the housing pressure 301 as the ordinate and the supply pressure 302 as the abscissa. However, if desired, ​ The two-dimensional Cartesian coordinate system 300 can have the supply pressure 302 as the ordinate and the housing pressure 301 as the abscissa.

[0124] List of reference signs

[0125] 10 Hydraulic system capable of detecting a fault

[0126] 100 Hydraulic system

[0127] 110 Tank

[0128] 120 Hydraulic fluid

[0129] 130 Hydraulically operated device

[0130] 140 Supply line

[0131] 150 Housing discharge line

[0132] 160 Pump

[0133] 170 Return line

[0134] 180 Filter

[0135] 190 Drive mechanism

[0136] 200 Fault detection device

[0137] 210, 220 Pressure sensor

[0138] 230 Temperature sensor

[0139] 240 Monitoring and fault detection unit

[0140] 250 Monitoring unit

[0141] 260 Fault detection unit

[0142] 270 Calibration unit

[0143] 280 Output device

[0144] 300 Two-dimensional Cartesian coordinate system

[0145] 301 casing pressure

[0146] 302 supply pressure

[0147] 310, 320 predetermined tolerance range of relative pressure values

[0148] 330, 331, 332, 333, 334, 335 calibration points

[0149] 341 pair of supply pressure and casing pressure at a first timestamp

[0150] 342 pair of supply pressure and casing pressure at a second timestamp

[0151] 343 pair of supply pressure and casing pressure at a third timestamp

[0152] 344 pair of supply pressure and casing pressure at a fourth timestamp

[0153] 345 pair of supply pressure and casing pressure at an n-th timestamp

[0154] 350 trend monitoring indicative of a pump failure

[0155] 360 trend monitoring indicative of a device failure of a hydraulically operated device

[0156] 390 failure-free operation curve

[0157] 400 method

[0158] 410, 420, 430, 440, 450, 460, 470 operation

Claims

1. A fault detection device (200) for a hydraulic system (100), the hydraulic system (100) comprising: a tank (110) with hydraulic fluid (120); a plurality of hydraulically operated devices (130); a supply line (140); a pump (160) carrying the hydraulic fluid (120) from the tank (110) to the plurality of hydraulically operated devices (130) via the supply line (140); and a housing drain line (150) for sending hydraulic fluid (120) from the pump (160) back to the tank (110), wherein the fault detection device (200) comprises: a first pressure sensor (210) sensing a first pressure value of the hydraulic fluid (120) in the supply line (140); a second pressure sensor (220) sensing a second pressure value of the hydraulic fluid (120) in the housing drain line (150); and a monitoring and fault detection unit (240) receiving the first and second pressure values from the first and second pressure sensors (210, 220) and comprising: a monitoring unit (250) monitoring the first and second pressure values from the first and second pressure sensors (210, 220) during operation of the plurality of hydraulically operated devices (130); and a fault detection unit (260) memorizing a plurality of pairs (341, 342, 343, 344, 345) of the first and second pressure values, wherein a first predetermined tolerance range of relative pressure values (310) and a second predetermined tolerance range of relative pressure values (320) are set, and wherein the fault detection unit (260) detects a fault of at least one of the plurality of hydraulically operated devices (130) when one of the plurality of pairs (341, 342, 343, 344, 345) is within the first predetermined tolerance range of relative pressure values (310) and outside the second predetermined tolerance range of relative pressure values (320), and wherein the fault detection unit (260) detects a fault of the pump (160) when the pair of the plurality of pairs (341, 342, 343, 344, 345) is outside the first predetermined tolerance range of relative pressure values (310); wherein the monitoring and fault detection unit (240) generates a fault-free operating curve (390) based on extrapolation of the first and second pressure values received by the monitoring and fault detection unit (240) when the hydraulic system (100) is in a calibration mode; wherein the monitoring and fault detection unit (240) determines the first predetermined tolerance range of relative pressure values (310) and the second predetermined tolerance range of relative pressure values (320) based on the fault-free operating curve (390).

2. The fault detection device (200) according to claim 1, wherein The fault detection unit (260) determines a trend (350, 360) based on the plurality of pairs (341, 342, 343, 344, 345), and wherein the fault detection unit (260) detects at least one of a fault of at least one of the plurality of hydraulically operated devices (130) and a fault of the pump (160) based on the trend (350, 360).

3. The fault detection apparatus (200) of claim 1, further comprising: a temperature sensor (230) that senses a current temperature value of the hydraulic fluid (120) in the tank (110) and provides the current temperature value to the monitoring and fault detection unit (240), and wherein the fault detection unit (260) adjusts the first predetermined tolerance range (310) of the relative pressure values and the second predetermined tolerance range (320) of the relative pressure values based on the current temperature value of the hydraulic fluid (120).

4. The fault detection device (200) of claim 1, wherein, The monitoring and fault detection unit (240) further comprises: a calibration unit (270) that determines the first predetermined tolerance range (310) of the relative pressure values and the second predetermined tolerance range (320) of the relative pressure values based on the first pressure values and the second pressure values received from the first pressure sensor (210) and the second pressure sensor (220) during an initial calibration of the hydraulic system (100) prior to operation of the plurality of hydraulically operated devices (130).

5. The fault detection device (200) according to claim 4, wherein The calibration unit (270) determines the first predetermined tolerance range (310) of the relative pressure values and the second predetermined tolerance range (320) of the relative pressure values based on predetermined operating conditions of the pump (160).

6. The fault detection apparatus (200) of claim 2, further comprising: a temperature sensor (230) that senses a current temperature value of the hydraulic fluid (120) in the tank (110) and provides the current temperature value to the monitoring and fault detection unit (240), and wherein the fault detection unit (260) adjusts the first predetermined tolerance range (310) of the relative pressure values and the second predetermined tolerance range (320) of the relative pressure values based on the current temperature value of the hydraulic fluid (120).

7. The fault detection device (200) according to any of the preceding claims, wherein The monitoring and fault detection unit (240) further comprises: an output device (280) that outputs at least one of the monitored first pressure values and second pressure values of the hydraulic fluid (120), a detected fault of at least one of the plurality of hydraulically operated devices (130), or a detected fault of the pump (160).

8. A hydraulic system (10) capable of detecting faults, comprising: a hydraulic system (100) comprising: a tank (110) having a hydraulic fluid (120); a plurality of hydraulically operated devices (130); a supply line (140); a pump (160) that is in fluid communication with the tank (110) and the plurality of hydraulically operated devices (130) via the supply line (140); and a first pressure sensor (210) and a second pressure sensor (220) that are in fluid communication with the supply line (140) and the tank (110) and that are configured to sense a first pressure value and a second pressure value of the hydraulic fluid (120) in the tank (110), respectively, and to provide the first pressure value and the second pressure value to a monitoring and fault detection unit (240). a pump (160) to transport the hydraulic fluid (120) from the tank (110) to the plurality of hydraulically operated devices (130) via the supply line (140); a return line (170) to return the hydraulic fluid (120) from the plurality of hydraulically operated devices (130) to the tank (110); and a housing drain line (150) to return hydraulic fluid (120) from the pump (160) to the tank (110); and a fault detection device (200) according to any of the preceding claims.

9. The fault detectable hydraulic system (10) according to claim 8, wherein, The hydraulic system (100) further comprises: a filter (180) in the supply line (140) between the pump (160) and the plurality of hydraulically operated devices (130).

10. The fault detectable hydraulic system (10) of claim 8, wherein, The hydraulic system (100) further comprises: a drive mechanism (190) to drive the pump (160).

11. A method of operating a fault detection device (200) according to any of claims 1 to 7, comprising: sensing, with the first pressure sensor (210), the first pressure value of the hydraulic fluid (120) in the supply line (140); sensing, with the second pressure sensor (220), the second pressure value of the hydraulic fluid (120) in the housing drain line (150); receiving, with the monitoring and fault detection unit (240), the first and second pressure values from the first and second pressure sensors (210, 220); monitoring, with the monitoring unit (250) in the monitoring and fault detection unit (240), the first and second pressure values from the first and second pressure sensors (210, 220) when the hydraulic system (100) is in a normal operating mode; memorizing, with the fault detection unit (260) in the monitoring and fault detection unit (240), the plurality of pairs (341, 342, 343, 344, 345) of the first and second pressure values in the normal operating mode; detecting, with the fault detection unit (260) in the monitoring and fault detection unit (240), a fault of the at least one of the plurality of hydraulically operated devices (130) when the pair of the plurality of pairs (341, 342, 343, 344, 345) is within a first predetermined tolerance range (310) of the relative pressure value and outside a second predetermined tolerance range (320) of the relative pressure value; and detecting, with the fault detection unit (260), a fault of the pump (160) when the pair of the plurality of pairs (341, 342, 343, 344, 345) is outside the first predetermined tolerance range (310) of the relative pressure value.

12. The method according to claim 11, further comprising: determining, with the monitoring and fault detection unit (240), a trend (350, 360) based on the plurality of tuples (341, 342, 343, 344, 345); and detecting, based on the trend (350, 360), at least one of a fault of at least one of the plurality of hydraulically operated devices (130) and a fault of the pump (160).

13. The method of claim 12, further comprising: generating and providing, based on the plurality of tuples (341, 342, 343, 344, 345) at different timestamps, statistical figures regarding the first pressure value and the second pressure value of the hydraulic fluid (120).

14. The method of claim 13, further comprising: in response to detecting the fault of the at least one of the plurality of hydraulically operated devices (130) or in response to detecting the fault of the pump (160), notifying an operator of the hydraulic system (100) of the detected fault.

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