• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    Device and method for detecting malfunctions of at least one hydraulic actuator for operating a functional element. A number of sensors are provided on the actuator for detecting operating parameters, the signals of which can be read out via an evaluation unit. At least two acceleration sensors are arranged at a distance from each other. The evaluation unit is arranged to correlate acceleration signals from the acceleration sensors and to determine a correct function or a functional failure from the deviation of the signals.
    公开号:NL2022338A
    申请号:NL2022338
    申请日:2019-01-03
    公开日:2019-07-10
    发明作者:Caspers Leo
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:


    Netherlands Patent Office
    Θ 2022338 © A PATENT APPLICATION (2 ) Application number: 2022338
    Application submitted: January 3, 2019
    Int. Cl .:
    F15B 15/20 (2019.01)
    (30) Priority: 0 Applicant (s): January 4, 2018 DE DE 10 2018 200 066.2 ROBERT BOSCH GMBH in Stuttgart,Federal Republic of Germany, DE. © Application registered:July 10, 2019 0 Inventor (s):Leo Caspers in Eindhoven. 0 Request published:July 10, 2019 © Authorized representative:ir. C.M. Jansen et al. In The Hague.
    54) Device and method for detecting malfunctions of a hydraulic actuator.
    57) Device and method for detecting malfunctions of at least one hydraulic actuator for operating a functional element. A number of sensors are provided on the actuator for detecting operating parameters, the signals of which can be read out via an evaluation unit. At least two acceleration sensors are arranged at a distance from each other. The evaluation unit is arranged to correlate acceleration signals from the acceleration sensors and to determine a correct function or a malfunction from the deviation of the signals.
    NL A 2022338
    This publication corresponds to the documents originally submitted.
    Device and method for detecting functional failures of a hydraulic actuator
    Description
    The invention relates to a device and method for detecting malfunctions, such as a stick-slip effect of a hydraulic actuator.
    From WO 2016/096548 A1 of the applicant it is known to design a hydraulic actuator, for example a hydraulic cylinder with several sensors, with which the operating conditions of the hydraulic cylinder can be determined. Such sensors may for example be designed as an acceleration sensor, as a pressure sensor or the like. In the method described in the solution implemented in WO 2016/096548 A1, these sensors are integrated in the hydraulic cylinder.
    In EP 2138744 B1, a device is disclosed in which sensors are integrated in a sealing arrangement in which the wear of the seals can be detected.
    A problem with, in particular, hydraulic cylinders is the so-called stick-slip effect - also referred to as an adhesion-sliding effect - which involves a jerky sliding of fixed parts moving relative to each other. Such a stick-slip effect occurs, for example, with rattling windshield wipers or creaking doors. With pneumatics and hydraulics, this effect mainly occurs if the static friction is greater than the sliding friction. In this connection, adhesion frictional forces which are considerably higher than sliding frictional forces can occur, particularly in the area of seals on the piston rod and the piston of a hydraulic cylinder, so that the stick-slip effect occurs in particular at the beginning of the piston movement, which can lead to undesired vibrations of the system and therefore premature material fatigue or premature wear.
    On the other hand, it is an object of the invention to provide a device and method for detecting failure of hydraulic actuators, whereby the stick-slip effect can be reliably detected, so that appropriate countermeasures can be taken on the basis of this evaluation.
    This object is achieved with respect to the device by the feature combination of claim 1 and with respect to the method by the feature combination of the independent claim 9.
    Advantageous embodiments of the invention are the subject of the dependent claims.
    The inventive device for detecting malfunctions of at least one hydraulic actuator has a number of sensors for detecting operating parameters whose signals can be read out via a gateway, hereinafter referred to as the evaluation unit. As sensors, at least two acceleration sensors are arranged at a distance from each other, the signals of which are evaluated by the evaluation unit. This is designed to correlate the acceleration signals from the sensors and to determine a good function or functional failure from the deviation of the signals - for example from a predetermined threshold value.
    According to the invention, therefore, the vibrations are recorded with the pre-installed acceleration sensors at or in the actuator remote positions. From a comparison of these and possibly other measurement signals, for example measured by pressure sensors, it can then be determined whether these vibrations relate to malfunctions based on the stick-slip effect, or whether these vibrations result as a result of correct operation of the actuator.
    By pre-installation of the sensors according to the invention and the evaluation / transmission unit, any malfunctions occurring during use can be quickly detected and corresponding countermeasures initiated. In this way, standstill times of the actuator can be avoided, whereby the analysis of the malfunction functions can be performed in a simple manner, without having to have experts at the location.
    In a particularly preferred embodiment, the actuator is designed as a hydraulic cylinder with a cylinder housing and a piston guided therein, which has at least one piston rod. An acceleration sensor is arranged on the head side, that is to say on the end portion of the cylinder housing located on the piston side. At least a further acceleration sensor is then arranged on the underside or in between on the cylinder housing. In the case where the hydraulic cylinder is designed as a synchronous cylinder, the final acceleration sensor can also be arranged in the central area of the cylinder housing or at the outlet of the further piston rod.
    The measurement accuracy can be further improved if a further acceleration sensor is arranged on the piston rod side.
    In applications in which a hydraulic cylinder is pivotally mounted via a cylinder hinge and / or the piston rod engages a functional element driven by the actuator via a hinge, a further acceleration sensor can be arranged on the cylinder hinge and / or around the latter hinge.
    For detecting the frictional forces, the hydraulic actuator can be designed with at least one further pressure sensor. The evaluation unit is accordingly designed in such an embodiment to determine the forces acting on the actuators from the pressure signals of the pressure sensors. In addition, it is preferable if the pressure signals are correlated with the signals from the acceleration sensors.
    The acceleration sensors can be arranged in a radial or axial direction with respect to the cylinder housing.
    The device according to the invention can also be designed with two or more actuators arranged in parallel, each of which can be designed in the manner described above with pressure and / or acceleration sensors. The evaluation unit is then designed to correlate the corresponding signals from both actuators for evaluation.
    In a particularly preferred embodiment, the actuator is provided for operating a gate of a barrier.
    The claimed method for detecting malfunctions of an actuator has the following steps accordingly:
    Detecting vibrations by remote control, on the actuator for installed acceleration sensors, comparing / correlating the detected vibrations and determining a malfunction when the detected signals from the acceleration sensors have deviations that exceed a threshold value.
    This threshold value can be set separately for each application.
    As explained above, these malfunctions are preferably based on stick-slip effects.
    The monitoring of the sensor signals is preferably performed continuously, so that malfunctions are quickly detected.
    In one embodiment, the evaluation may include cross-correlation of the signals, with pressure and acceleration signals being correlated.
    Preferred embodiments of the invention are explained in more detail below with reference to schematic drawings. It shows:
    Figure 1 is a schematic diagram of a device for detecting function 20 faults;
    Figure 2 shows a concrete embodiment of a barrier,
    Figure 3 shows measurement signals of two accelerometers of a hydraulic cylinder of a barrier according to Figure 2;
    Figure 4 is an enlarged detailed view of the measurement signals according to Figure 3;
    Figures 5, 6 a statistical analysis of the signals according to figures 3 and 4 after the cross-correlation;
    Figure 7 further statistical analysis of signals obtained on different strokes of the hydraulic cylinder of a barrier according to Figure 2, and
    Figure 8, the basic principle of calculating the forces on the cylinder on the basis of detected signals by means of pressure sensors.
    Figure 1 shows the basic principle of a device 1 for detecting malfunctions, in particular stick-slip effects that occur with a hydraulic cylinder 2. In a known manner, the hydraulic cylinder 2 has a cylinder housing 4, in which a piston is guided axially slidably. 6 The hydraulic cylinder 2 is designed as a differential cylinder, whereby the piston 6 accordingly has a piston rod 8, which is created on one side of the cylinder housing. The piston 6 divides the interior of the hydraulic cylinder 2 into an annular chamber 10 on the piston rod side and a lower pressure chamber 12. In the illustrated embodiment, for example, the cylinder housing 4 is hinged to a foundation by means of a cylindrical hinge 14 of such. The piston rod 8 engages on a hinge 16 on a functional element to be operated.
    As indicated in Figure 1, in the region of this hinge 16, in the area of the cylindrical hinge 14 or in the area of a bottom 18 and at the location of a cylinder head 20 of the cylinder housing 4, there are in each case an acceleration sensor 22, 24 and 26, via which vibrations can be detected during operation of the hydraulic cylinder. In the illustrated embodiment, pressure sensors 28, 30 and 15 are further shown, through which the pressure in the annular space 10 and in the pressure chamber 12 can be detected.
    The signals from the sensors 22, 24, 26, 28, 30 are, as in Figure 1, fed via signal lines to a gateway arranged on the hydraulic cylinders 2. This gateway may, for example, be in the form of a signal reservoir with a data transfer device with a central evaluation unit, or even as an evaluation unit 32, via which the detected signals are stored and processed. This edited information can be passed on via an integrated interface for evaluation / processing at a central station or directly read out.
    By evaluating the signals from the acceleration sensors 22, 24, 26 and the pressure sensors 28, 30, a functional failure can be detected with relatively little effort, in particular vibrations obtained as a result of the stick-slip effect.
    This can be particularly advantageous in applications implemented with very large hydraulic cylinders 2, such as used in for example weirs / dams, which are provided with gates that are opened or closed by means of the hydraulic cylinder 2. Such a solution is indicated in Figure 2. In this barrier (sea barrier) 33, at least one hydraulic cylinder 2 of the type described above is rotatably mounted on a foundation 34 via the cylinder connection 14. The piston rod 8, which is approximately in the vertical direction and is extendable and extendable, engages via hinge 16 on a console 36 of a gate 38, which closes a flow. The water level is indicated by the reference numeral 40. To open the barrier 33, the door 38 can be adjusted upwards (view of figure 2) by withdrawing the piston rod 8 to the dotted line, with a bottom 42 then above the water level (see dotted view in figure 2) is indicated. Due to the slightly curved configuration of the door 38, the hydraulic cylinder 2 performs a slight pivotal movement around the cylinder joint 14 during this opening movement. The closing of the door 38 is then performed again by sliding the piston rod.
    In the exemplary embodiment shown in Figure 2, an acceleration sensor 24 is accordingly arranged in the area of the cylinder connection 14. Another acceleration sensor 44, not shown in Figure 1, is arranged on the cylinder housing 4 and the acceleration sensor 26 on the cylinder head. A fourth acceleration sensor 22 is then - as explained in Figure 1 - arranged on the hinge 16 via which the piston rod 8 is connected to the bracket 36. The pressure in the hydraulic cylinder 2 is detected by the pressure sensors 28, 30 not shown in Figure 2. .
    When detecting stick-slip effect, it is preferable if the acceleration sensors 24, 26, 44 are respectively arranged in the axial direction of the cylinder. The acceleration sensor 16 piston rod side is in the longitudinal direction of the piston rod 8 and therefore also oriented in the axial direction of the hydraulic cylinder. 2
    In principle, the cylinder side sensors can be arranged in a radial direction - however, it appears that in such a mutual positioning the stick-slip effects cannot be determined as well as in a device in the axial direction.
    Stark schematically and by way of example, signals are detected with the acceleration sensors 26 (cylinder head) 24 (cylinder hinge) and 44 (cylinder jacket) in figures 3 and 4, the acceleration (m / s 2 ) being recorded over time. It can be seen that the amplitude of the vibrations detected by the sensor 26 is considerably greater than that of the accelerations detected by the sensors 24 and 44. The period of the vibrations is about the same. Because these measurement signals are superimposed with interfering signals, statistical methods are used to facilitate the evaluation.
    Figure 5 shows a cross-correlation of the acceleration values detected via the sensors 44 (cylinder housing) and 26 (cylinder head). In a cross-correlation of this type, a signal from an acceleration sensor that is displaced by a value T is multiplied by that of the other sensor and the result is integrated to simplify matters. If both signals are basically the same but have shifted over time with the value ΔΤ, the correlation function has a maximum at ΔΤ.
    Figure 5 shows such a cross-correlation over the entire time range from -5 to +5 seconds. Figure 6 shows the area highlighted in Figure 5 in a highly enlarged detailed view, showing a time range of about -5 to +5 milliseconds (ms). In this representation it can be seen that the time shift ΔΤ described above is approximately 0.2 ms. This means that the vibration on the cylinder housing (signal from the acceleration sensor 44) is slightly ahead of the vibration on the cylinder head 20 (acceleration sensor 26). As can be seen in particular from the illustration according to figure 5, the correlation sharply decreases in the range of times removed from 0.
    Figure 7 now shows cross-correlations that correspond to Figure 6 for different strokes of the piston rods. In this display it can be seen that the signal shift ΔΤ changes with increasing stroke to the negative. From this it can be deduced that the resulting vibrations and the associated stick-slip effects are dependent on the stroke of the piston.
    If the main cause of malfunctions in the area of the cylinder head 20 were to occur, then this time shift ΔΤ represented by the peak of the curves according to Figs. 6 and 7 would be more or less constant and have a negative value . In other words, it can be easily deduced from the hub-time change of time shift that the stick-slip effect results from the interior of the hydraulic cylinder, in particular the configuration of the piston. This is less a classic stick-slip phenomenon, but rather vibration due to extreme dynamic friction and / or high adhesion in the area of the piston to the cylinder housing.
    This high dynamic friction can also be minimized by a suitable choice of pressure medium.
    Finally, Figure 8 shows yet how the forces acting in the hydraulic cylinder 2 can be determined from the signals of the pressure sensors 28, 30. The pressure p, z are detected in the pressure chamber 12 and the pressure P s in the annular space 10 via the two sensors 28, 30. The forces in the opening direction F o and in the closing direction F s can then be easily calculated from the pressure and the active surfaces A (bottom surface) and Ar (ring area) of the piston 6. The load carried by the piston rod 8 must be F grav corresponds to the weight of the door 38 which occurs due to gravity. This weight force contributes to the force F o and acts in opposition to the force F s acting in the closing direction. The friction force F R is then calculated from the difference between the force FO and Fs divided by 2 (Fr = (F o - Fs) / 2).
    This force due to friction can therefore be used in the evaluation of the measurement results. For example, if it appears that the frictional force increases during the service life of the hydraulic cylinder 2, then a problem in the area of the connection, or an increase in the roughness of the cylinder liner or the piston 6 / the piston rod 8 due to a premature suspect wear.
    The solution according to the invention makes it possible to detect malfunctions of a hydraulic actuator, for example a hydraulic cylinder, without major effort, and to intervene in time.
    It is preferable that the aforementioned forces be absorbed in a condition of the device in which external influences on the frictional forces, for example the sliding of a sealing lip on the foundation or the like, are minimal.
    In such a barrier 33, due to the high weight of the door 38, two or more hydraulic cylinders 2 can be used for operation. In this case, each of the hydraulic cylinder 2 is then preferably equipped with a sensor device according to the above, so that in operation the individual, mutually corresponding sensor signals of the parallel-operating hydraulic cylinder 2 can be compared to draw conclusions about function malfunctions, such as leading. from a hydraulic cylinder or the like.
    Described are a device and a method for detecting malfunctions of at least one hydraulic actuator, wherein vibrations of the actuator are detected and compared with each other via a number of acceleration sensors.
    权利要求:
    Claims (12)
    [1]
    Conclusions
    An apparatus for detecting function malfunctions of at least one hydraulic actuator for operating a functional element, wherein on the actuator a
    A plurality of sensors are provided for detecting operating parameters whose signals can be read out via an evaluation unit (32), wherein at least two acceleration sensors (22, 24, 26, 44) are arranged remotely from each other and wherein the evaluation unit (32) is arranged to correlate acceleration signals from the acceleration sensors (22, 24, 26, 44) and to derive a correct
    10 function or a functional failure.
    [2]
    Device as claimed in claim 1, wherein the actuator is a hydraulic cylinder (2) with a cylinder housing (4) and a piston (6) guided therein with at least one piston rod (8), wherein an acceleration sensor (26) on the cylinder head side is a further acceleration
    15 is arranged on the housing side and / or an acceleration sensor (24) on the underside of the cylinder housing (4).
    [3]
    Device according to claim 1 or 2, with an acceleration sensor (22) on the piston rod side.
    [4]
    Device as claimed in any of the foregoing claims, wherein the hydraulic cylinder (2) is pivotally arranged via a cylinder hinge (14) and / or the piston rod (8) engages the functional element via a hinge (16), wherein an acceleration sensor (24) on the cylinder hinge (14) and / or an acceleration sensor (22) on the hinge (16)
    25 furnished.
    [5]
    Device as claimed in any of the foregoing claims, with a pressure sensor (28, 30) in at least one pressure chamber (10, 12) of the actuator, wherein the evaluation unit (32) is adapted to exert forces acting from the pressure signals in the actuator determine where
    30 preferably pressure signals are correlated with the signals from the acceleration sensors.
    [6]
    Device according to one of the preceding claims, in which the acceleration sensors (22, 24, 26, 44) are arranged in axial direction with respect to the cylinder housing (4).
    [7]
    Device as claimed in any of the foregoing claims, wherein it has two or more actuators, each of which is equipped with acceleration sensors (22, 24, 26, 44) according to any one of the preceding claims, wherein the evaluation unit (32) is arranged to receive the signals of the two actuators.
    [8]
    Device as claimed in any of the foregoing claims, wherein the actuator is provided for operating a barrier (33).
    [9]
    9. Method for detecting malfunctions of an actuator, comprising the steps of:
    - detecting vibrations by means of spaced, preferably pre-installed, acceleration sensors (22, 24, 26, 44),
    - comparing the detected vibrations and
    - recognizing a malfunction if the detected signals show deviations above a threshold value.
    [10]
    The method of claim 9, wherein the malfunctions are stick-slip effects.
    [11]
    11. Method as claimed in claim 9 or 10, wherein the evaluation comprises a cross-correlation of the signals.
    [12]
    A method according to any of claims 9-11, wherein the acceleration sensors (22, 24, 26, 44) are installed on the actuator and permanently attached.
    1/5
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    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
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