Method for determining an opening point position value and valve device

Abstract

A method for determining an opening point position value (39) of a valve device (16) having a valve unit (1) designed as a piezo valve unit, wherein the opening point position value (39) describes the position of a valve member (6) of the valve unit (1) at which the valve member (6) transitions from a closed state to an open state, wherein the method comprises the steps of: - providing a drive variable signal curve (51), in particular a drive variable ramp, in order to drive the valve member (6) with a drive variable, namely an electrical voltage, so that the valve member (6) is moved from the closed state to the open state and / or from the open state to the closed state, - while providing the drive variable signal curve (51), recording a position characteristic curve (36) of the valve member (6) as a function of the drive variable, - based on the recorded position characteristic curve (36),Determining the opening point position value (39), wherein the valve device (16) performs a position control of the valve member (6) using the opening point position value (39).

Description

[0001] The invention relates to a method for determining an opening point position value of a valve device having a valve unit designed as a piezo valve unit, wherein the opening point position value describes the position of a valve member of the valve unit at which the valve member changes from a closed state to an open state.

[0002] EP 0 794 373 A1 relates to a method and a device for determining the response point of a safety valve.

[0003] EP 3 368 775 B1 relates to a fluid control device and a method for operating a fluid control device.

[0004] DE 10 2016 206 822 A1 relates to a method for supplying compressed air to a compressed air consumer.

[0005] An object of the invention is to provide a reliable method for determining the opening point position value.

[0006] The object is achieved by a method according to claim 1. The method comprises the steps: - Providing a drive variable signal curve, in particular a drive variable ramp, to drive the valve member with a drive variable, namely an electrical voltage, so that the valve member is moved from the closed state to the open state and / or from the open state to the closed state, - while providing the actuator size signal curve, recording a position characteristic of the valve element as a function of the actuator size and - Based on the recorded position characteristic, determining the opening point position value. The valve device performs position control of the valve element using the opening point position value.

[0007] Based on the recorded position characteristic curve, the position of the valve element at which it changes from the closed state to the open state can be identified. This enables a reliable determination of the opening point position value.

[0008] Providing the drive variable signal curve, recording the position characteristic curve, and determining the opening point position value shall collectively be referred to as the opening point determination procedure. Preferably, the valve device performs the opening point determination procedure repeatedly, for example, periodically, in order to determine a current opening point position value.

[0009] Aging of a flexible sealing element (e.g., a sealing pad), temperature influences in the measuring system, the mounting of the valve to the measuring board, and / or a floating bearing of the valve element in the valve unit can all lead to a change in the actual opening point position value. An opening point variable is conveniently stored in the valve device to represent the actual opening point position value and is conveniently used for control implemented with the valve unit. If the actual opening point position value changes over time and no longer matches the opening point variable, this can impair the control, particularly by reducing the control quality.For example, it is possible that a control system executing the control assumes the closed state even though the valve unit is actually still in the open state, or that the valve unit is still in the closed state even though the control system already requests a slight valve opening—i.e., the open state. Furthermore, if the opening point variable deviates from the actual opening point position value, it is possible that the actual flow rate through the valve unit differs from the set flow rate. The opening point determination procedure explained above makes it possible to adapt the opening point variable to the actual opening point position value, thereby avoiding the problems mentioned.

[0010] Advantageous further training is the subject of the subclaims.

[0011] The invention further relates to a method according to claim 4 and a method according to claim 7.

[0012] The invention further relates to a valve device according to claim 11.The valve device has a valve unit which is designed as a piezo valve unit and has a valve member which can be moved from a closed state to an open state by means of a drive variable, namely an electrical voltage, wherein the valve device is designed to provide a drive variable signal curve, in particular a drive variable ramp, in order to drive the valve member so that the valve member is moved from the closed state to the open state and / or from the open state to the closed state, to provide a position characteristic curve of the valve member as a function of the drive variable while providing the drive variable signal curve and to determine an opening point position value on the basis of the recorded position characteristic curve, wherein the opening point position value describes the position of the valve member at which the valve member changes from the closed state to the open state.The valve device is designed to perform position control of the valve member using the opening point position value.

[0013] Further exemplary details and exemplary embodiments are explained below with reference to the figures. Fig. 1 a schematic representation of a valve unit, Fig. 2 a schematic representation of a valve device, Fig. 3 a block diagram of a control loop, Fig. 4 a position characteristic of a valve element as well as a rotated position characteristic and Fig. 5 a time course of a drive variable with a drive variable signal curve.

[0014] The Fig. 1 shows a valve unit 1, which is embodied as a piezo valve unit. The valve unit 1 has a valve unit housing 2, which exemplifies the outer housing of the valve unit 1. The valve unit 1 has a fluid channel 3, which runs particularly within the valve unit housing 2, for example from a first fluid port 4 to a second fluid port 5 of the valve unit 1. The first fluid port 4 and the second fluid port 5 are expediently arranged on the outside of the valve unit housing 2.

[0015] The valve unit 1 has a valve member 6, which can expediently be placed either in a closed state or an open state. The valve unit 1 is preferably a proportional valve. In the closed state, the valve member 6 interrupts the fluid channel 3, so that in the closed state, fluid is prevented from flowing via the fluid channel 3 from the first fluid port 4 to the second fluid port 5. In the open state, the valve member 6 releases the fluid channel 3, so that in the open state, fluid can flow via the fluid channel 3 from the first fluid port 4 to the second fluid port 5. The valve member 6 is exemplified as a piezo bending actuator. According to an alternative embodiment, the valve member is a fluidically, in particular pneumatically, actuated valve member.

[0016] In the Fig. 1, the valve member 6 is shown in the closed state. By providing a drive variable, for example an electrical voltage, the valve member 6 can be moved from the closed state to the open state. In the example of Fig. 1, the valve member 6 moves in the direction of the arrow marked with the reference numeral 7 by applying a corresponding electrical voltage in order to assume the open state.

[0017] The valve unit 1 preferably has an elastic sealing element 8. In the closed state, the valve member 6 rests against the elastic sealing element 8. Expediently, the valve member 6 does not rest against the elastic sealing element 8 in the open state. In particular, in the closed state, the valve member 6 rests against the elastic sealing element 8 with a closure section 9 (of the valve member 6), and in the open state, the closure section 9 does not rest against the elastic sealing element 8. The closure section 9 is expediently arranged at an end of the valve member 6 located in the longitudinal direction of the valve member 6 and, in the closed state, expediently interrupts the fluid channel 3. The elastic sealing element 8 is expediently designed with a higher elasticity than the valve member 6 and / or the valve member housing 2. By way of example, the elastic sealing element 8 has a sealing element opening 10 through which the fluid channel 3 runs.In the closed state, the valve member 6 closes the sealing element opening 10, and in the open state, the valve member 6 releases the sealing element opening 10. For example, the elastic sealing element 8 is designed as a valve seat and / or sealing pad.

[0018] The valve unit 1 further comprises, by way of example, a spring element 11 which acts on the valve member 6 and expediently exerts a force on the valve member 6 in the direction towards the closed state.

[0019] The valve unit 1 expediently also has a computer unit 12, for example a microcontroller, which is expediently arranged in the valve unit housing 2. For example, the computer unit 12 is arranged on a printed circuit board 13.

[0020] The valve unit 1 expediently has a position sensor 14 for detecting the position of the valve member 6. The position sensor 14 is particularly designed to directly detect the position of the valve member 6. For example, the position sensor 14 is designed as a magnetic field sensor, for example, a Hall sensor. For example, a magnet 15 is arranged on the valve member 6, in particular on the closure section 9, whose magnetic field is detected by the magnetic field sensor. Purely for the sake of example, the position sensor 14 is arranged on the circuit board 13.

[0021] The Fig. 2 shows a valve device 16. The valve device 16 comprises the valve unit 1. By way of example, the valve device 16 comprises a plurality of valve units 1, which are expediently each designed like the valve unit 1 explained above. Purely by way of example, the valve device 16 comprises four valve units 1, namely a first valve unit 1A, a second valve unit 1B, a third valve unit 1C and a fourth valve unit 1D. The valve units 1 are connected, by way of example, as a bridge, in particular as a full bridge. By way of example, the first valve unit 1A and the second valve unit 1B together form a first half-bridge. By way of example, the third valve unit 1C and the fourth valve unit 1D together form a second half-bridge.

[0022] The valve device 16 comprises, by way of example, a fluid source 17, which is particularly designed as a compressed air source. The valve device 16 further comprises, by way of example, a fluid sink 18, which is particularly designed as a compressed air sink.

[0023] The valve device 16 expediently has a first working outlet 19 and / or a second working outlet 20. The first valve unit 1A is fluidically connected between the fluid source 17 and the first working outlet 19, so that a fluidic connection between the fluid source 17 and the first working outlet 19 can be selectively established or interrupted via the first valve unit 1A. The second valve unit 1B is fluidically connected between the fluid sink 18 and the first working outlet 19, so that a fluidic connection between the fluid sink 18 and the first working outlet 19 can be selectively established or interrupted via the second valve unit 1B.The third valve unit 1C is fluidically connected between the fluid source 17 and the second working outlet 20, so that a fluidic connection between the fluid source 17 and the second working outlet 20 can be selectively established or interrupted via the third valve unit 1C. The fourth valve unit 1D is fluidically connected between the fluid sink 18 and the second working outlet 20, so that a fluidic connection between the fluid sink 18 and the second working outlet 20 can be selectively established or interrupted via the fourth valve unit 1D.

[0024] The valve device 16 expediently also has a fluidic actuator 21, which is designed, for example, as a fluidic drive, in particular as a pneumatic drive. For example, the fluidic actuator 21 is, in particular, a pneumatic drive cylinder or a particularly pneumatic valve drive. The fluidic actuator 21 has, for example, a first pressure chamber 22 and preferably a second pressure chamber 23. The first pressure chamber 22 is, for example, fluidically connected to the first working outlet 19. For example, the first pressure chamber is connected to the first working outlet 19 via a first fluidic line 24, for example, a first hose. The second pressure chamber 23 is, for example, fluidically connected to the second working outlet 20. For example, the second pressure chamber is connected to the second working outlet 20 via a second fluidic line 25, for example, a second hose.

[0025] By placing the first valve unit 1A in the open state (and expediently the second valve unit 1B in the closed state), pressurized fluid can be supplied to the first pressure chamber 22. By placing the second valve unit 1B in the open state (and expediently the first valve unit 1A in the closed state), pressurized fluid can be discharged from the first pressure chamber 22. By placing the third valve unit 1C in the open state (and expediently the fourth valve unit 1D in the closed state), pressurized fluid can be supplied to the second pressure chamber 23. By placing the fourth valve unit 1D in the open state (and expediently the third valve unit 1C in the closed state), pressurized fluid can be discharged from the first pressure chamber 22.

[0026] The Fig. Figure 3 shows a control loop 26, which includes, by way of example, a position controller 27, an adaptation algorithm 28, a drive variable controller 29, and a controlled system 30. The drive variable controller 29 is, by way of example, a voltage regulator.

[0027] Each valve unit 1 expediently provides such a control loop 26. For example, each valve unit 1 provides a respective position controller 27, a respective adaptation algorithm 28, and / or a respective drive variable controller 29 on its computer unit 12. The position controller 27, the adaptation algorithm 28, and / or the drive variable controller 29 of each valve unit 1 are expediently implemented as software. Each valve unit 1 expediently comprises a respective control system 30, which expediently comprises the respective valve element 6.

[0028] The following explanations apply expediently to each of the valve units 1 - in particular to the respective control circuit 26 of each valve unit 1.

[0029] The position controller 27 expediently receives a position setpoint signal 31, for example from a controller 50 of the valve device 16 (in particular present in addition to the valve units 1). Furthermore, the position controller 27 receives an actual position signal 32 (determined in particular using the position sensor 14), which represents the position of the valve member 6. Based on the position setpoint signal 31 and the actual position signal 32, the position controller 27 calculates a drive variable setpoint signal 33, in particular in such a way as to cause the actual position signal 32 to change toward the position setpoint signal 31. The drive variable setpoint signal 33 is preferably fed to the adaptation algorithm 28 and / or the drive variable controller 29. For example, the adaptation algorithm 28 forwards the drive variable setpoint signal 33 to the drive variable controller 29.Furthermore, the adaptation algorithm 28 (in particular instead of the drive variable setpoint signal 33) can supply a drive variable signal profile signal 43 to the drive variable controller, in particular during an opening point determination procedure. The drive variable signal profile signal 43 is in particular a drive variable ramp signal.

[0030] The drive variable controller 29 receives the drive variable setpoint signal 33 (or the drive variable signal profile signal 43) and expediently a drive variable actual value signal 34 and expediently calculates a drive variable control value signal 35 for controlling the controlled system 30, in particular for controlling the valve member 6, in particular in such a way as to cause the drive variable actual value signal 34 to change towards the drive variable setpoint signal 33 (or the drive variable signal profile signal 43). The drive variable setpoint signal 33 is, for example, a voltage setpoint signal, the drive variable actual value signal 34 is, for example, a voltage actual value signal, the control variable signal profile signal is, for example, a voltage signal profile signal and the drive variable control value signal is, for example, an electrical voltage signal with which the control system 30, in particular the valve element 6, is controlled.The voltage waveform signal is in particular a voltage ramp signal.

[0031] For example, the drive variable actual value signal 34 and / or the position actual value signal 32 is fed to the adaptation algorithm 28.

[0032] In the following, it will be discussed in more detail how an opening point position value 39 (exemplarily in Fig. 4). The following explanations expediently apply to each of the valve units 1 of the valve device 16. Expediently, the respective opening point position value is determined for each of the valve units 1 of the valve device in the manner explained below.

[0033] The opening point position value 39 describes the position of the valve member 6 of the valve unit 1 at which the valve member 6 transitions from the closed state to the open state. The opening point position value 39 describes, in particular, the position of the valve member 6 at which, starting from the closed state, the fluid channel 3, in particular the sealing element opening 10, begins to open and / or a flow, in particular a mass flow, of a pressurized fluid through the fluid channel 3, in particular the sealing element opening 10, is established and / or begins to flow.

[0034] A drive variable, in particular an electrical voltage or pressure, is used to drive the valve member 6. The value of the drive variable at which the valve member 6 transitions from the closed state to the open state shall be referred to as the drive variable opening value 38.

[0035] The opening point position value is determined in particular within the framework of an opening point determination procedure, which is preferably carried out by each of the valve units 1, in particular by the respective adaptation algorithm 28. The respective opening point determination procedure runs in particular as explained below: The valve device 16, in particular the valve unit 1 (exemplarily the computer unit 12), provides a drive variable signal curve 51 (exemplarily in the Fig. 5) to drive the valve member 6, so that the valve member 6 is moved from the closed state to the open state and / or from the open state to the closed state. The drive variable signal curve 51 is a signal section of the drive variable (in particular predetermined in terms of time and / or its signal curve), which is provided in particular specifically for determining the opening point position value. The drive variable signal curve can also be referred to as a drive variable signal section. The drive variable signal curve 51 is, for example, rising and / or falling, in particular monotonically rising or monotonically falling. The drive variable signal curve 51 is, in particular, a drive variable ramp.By way of example, the drive variable signal waveform 51 (in particular as the drive variable control value signal 35) is provided by the drive variable controller 29, in particular in response to the adaptation algorithm 28 supplying the drive variable signal waveform signal 43 to the drive variable controller 29.

[0036] The Fig. 5 shows a time course of the drive variable with the drive variable signal curve 51. In the Fig. In the diagram shown in Figure 5, time is plotted on the horizontal axis and the drive variable is plotted on the vertical axis. The drive variable signal curve 51, in particular the drive variable ramp, is expediently a monotonically, in particular strictly monotonically, increasing section of the temporal curve of the drive variable. For example, the drive variable signal curve, in particular the drive variable ramp, has the shape of a straight line with a positive gradient. The drive variable signal curve 51, in particular the drive variable ramp, expediently begins with an initial value 37 (exemplarily at a first time 52) and ends with an end value 40 (exemplarily at a second time 53). The drive variable signal curve 51 is preferably a signal curve of an electrical voltage. The drive variable ramp is preferably an electrical voltage ramp.

[0037] For example, the initial value 37 of the drive variable signal curve 51 is smaller than a value of the drive variable present immediately before the start (and / or after the end) of the drive variable signal curve. In particular, the initial value 37 of the drive variable signal curve 51 is smaller than a closed state value 54 of the drive variable that the valve unit 1 uses (in particular outside the opening point determination procedure, for example, within the scope of an application) to place the valve member 6 into the closed state.

[0038] During the provision of the drive variable signal curve 51, the valve device 16, in particular the valve unit 1 (for example the computer unit 12), draws a position characteristic curve 36 (exemplarily in the Fig. 4) of the valve member 6 as a function of the drive variable. By way of example, the adaptation algorithm 28 records the position characteristic curve 36, specifically based in particular on the drive variable actual value signal 34 and / or the position actual value signal 32. For example, the adaptation algorithm records the position actual value signal 32 as the position characteristic curve 36 as a function of the drive variable actual value signal 34.

[0039] To record the position characteristic curve 36, the valve device 16 detects the position of the valve member 6, preferably using the magnetic field sensor and the magnet 15 present on the valve member 6.

[0040] The valve device 16, in particular the valve unit 1 (exemplarily the computer unit 12), determines the opening point position value 39 on the basis of the recorded position characteristic curve 36. For example, the adaptation algorithm 28 calculates the opening point position value 39 on the basis of the recorded position characteristic curve 36.

[0041] The Fig. 4 shows an exemplary position characteristic curve 36 of the valve member 6 as a function of the drive variable (for example, an electrical voltage). The drive variable is plotted on the horizontal axis, and the position of the valve member 6 is plotted on the vertical axis. The position characteristic curve 36 begins at the initial value 37 (of the drive variable). The initial value 37 is, for example, an initial voltage value with which the valve member 6 is controlled at the beginning of the position characteristic curve 36. The position characteristic curve 36 comprises a first characteristic curve section 41, which is assigned to (in particular depicts) a first movement phase of the valve member 6, in which the valve member 6 is in the closed state. Preferably, the position characteristic curve 36 further comprises a second characteristic curve section 42, which is assigned to (in particular depicts) a second movement phase of the valve member 6, in which the valve member 6 is in the open state.The first characteristic curve section 41 begins at the initial value 37 and ends at the actuator size opening value 38. At the actuator size opening value 38, the valve member 6 assumes the opening position corresponding to the opening point position value 39. The second characteristic curve section 42 begins at the actuator size opening value 38 and ends at the final value 40 (the actuator size).

[0042] The valve device 16 has the elastic sealing element 8, against which the valve member 6 rests in the closed state. Preferably, the valve member 6 is pressed into the elastic sealing element 8 by the initial value 37 of the drive variable signal curve 51, so that the valve member 6, while the drive variable signal curve 51 is being provided, goes through the first movement phase in which the valve member moves toward the open state, while the valve member continues to rest against the elastic sealing element and is in the closed state. While the drive variable signal curve is being provided, the valve member 6 further goes through the second movement phase following the first movement phase, in which the valve member 6 is in the open state.

[0043] By way of example, the position characteristic curve 36 has a different gradient for the first movement phase (i.e. in the first characteristic curve section 41) than for the second movement phase (i.e. in the second characteristic curve section 42). The gradient of the first movement phase is, for example, the difference quotient of the first characteristic curve section 41, and the gradient of the second movement phase is, for example, the difference quotient of the second characteristic curve section 42. Purely by way of example, the gradient of the position characteristic curve 36 is constant in both the first movement phase and the second movement phase. By way of example, the gradient of the position characteristic curve 36 in the first movement phase is smaller than the gradient of the position characteristic curve 36 in the second movement phase. By way of example, the elastic sealing element 8 exerts a sealing element force (caused in particular by an elastic deformation of the sealing element 8) on the valve member 6 in the first movement phase (i.e. in the closed state).Conveniently, the elastic sealing element 8 does not exert the sealing element force on the valve member 6 in the second movement phase (i.e., in the open state). Accordingly, different forces act on the valve member 6 in the first movement phase than in the second movement phase, so that the position of the valve member 6 changes differently (here, for example, less strongly) depending on the drive variable in the first movement phase than in the second movement phase.

[0044] The gradient of the position characteristic curve 36 depends in particular on the stiffness of the sealing element 8 (in particular, designed as a sealing pad) in the first movement phase. The opening position 39 depends in particular on the force of the spring element 11 and a differential pressure acting on the valve member 6. The gradient of the position characteristic curve 36 depends in particular on the stiffness of the valve member 6 and the spring element 11 in the second movement phase.

[0045] The transition from the first characteristic curve section 41 to the second characteristic curve section 42 is, for example, a kink 44—that is, in particular, a discontinuous point in the first derivative of the position characteristic curve 36 (with respect to the drive variable). The valve device 16 (in particular, the valve unit 1, preferably the adaptation algorithm 28) expediently determines a position value of the valve member 6 at this kink 44 (that is, in particular, at the discontinuous point) as the opening point position value 39.

[0046] Preferably, the valve device 16 (in particular the valve unit 1, preferably the adaptation algorithm 28) performs a first rotation of the recorded position characteristic curve 36 (for example, by a predetermined first angle) by means of a mathematical operation in order to obtain a rotated position characteristic curve 47. The mathematical operation is, for example, a multiplication of the position characteristic curve 36 by a rotation matrix. The first rotation is indicated by the arrow provided with the reference number 45 in the Fig. 4. Preferably, the valve device 16 (in particular the valve unit 1, preferably the adaptation algorithm 28) determines the opening point position value 39 by detecting a minimum 46 of the rotated position characteristic curve 47.

[0047] Preferably, the valve device 16 (in particular the valve unit 1, preferably the adaptation algorithm 28) performs a second rotation of the minimum 46 opposite to the first rotation to determine the opening point position value 39 (for example, by a predetermined second angle, the magnitude of which is expediently equal to the magnitude of the first angle). The second rotation is indicated by the arrow provided with the reference number 48 in the Fig. 4. Conveniently, the valve device 16 (in particular the valve unit 1, preferably the adaptation algorithm 28) determines the position value of the valve member 6 at the minimum 46 rotated by the second rotation as the opening point position value 39. Optionally, the valve device 16 determines the value of the drive variable at the minimum 46 rotated by the second rotation as the drive variable opening value 38.

[0048] The first angle and / or the second angle are preferably calculated in advance, for example, based on how the stiffness effective for the valve member 6 changes from the first movement phase to the second movement phase. For example, the position characteristic curve 36 is rotated during the first rotation until the absolute value of the gradient of the first characteristic curve section 41 is equal to the absolute value of the gradient of the second characteristic curve section 42. Preferably, the valve device 16, in particular the adaptation algorithm 28, iteratively searches for the minimum 46 of the rotated position characteristic curve 47.

[0049] The opening point position value 39 - i.e. the position value of the valve member 6 at the transition or kink 44 between the first characteristic curve section 41 and the second characteristic curve section - can also be found in another way, in particular without rotating the position characteristic curve 36. For example, the opening point position value 39 can be determined using a recursive determination of a reference line, in particular based on the fact that an error between the position characteristic curve 36 and the reference line increases significantly (for example, exceeds a threshold value) as soon as the opening point position value 39 is exceeded.

[0050] Conveniently, the valve device 16, in particular the adaptation algorithm 28, terminates the opening point determination procedure in response to the opening point position value 39 having been determined. Upon completion of the opening point determination procedure, the adaptation algorithm terminates the output of the drive variable signal 43 and instead outputs the drive variable setpoint signal 33 (from the position controller 27) to the drive variable controller 29. For example, the valve device 16, in particular the valve unit 1, sets the drive variable to the closed state value 54 immediately after the completion of the opening point determination procedure.

[0051] The valve device 16, in particular the adaptation algorithm 28, expediently stores the determined opening point position value 39, for example, as the opening point variable. The valve device 16 preferably performs position control of the valve member 6 using the opening point position value 39. For example, the valve device 16 uses the opening point position value 39 during position control as a reference value, as an offset, and / or for calibration.

[0052] The valve device 16, in particular the adaptation algorithm 28, expediently compares the determined opening point position value 39 with a reference opening point (which was determined, for example, during a calibration of the respective valve unit 1). Preferably, the valve device 16, in particular the adaptation algorithm 28, stores the deviation between the determined opening point position value 39 and the reference opening point as a deviation value and expediently uses this deviation value in the position control.

[0053] Preferably, the valve device 16 provides the drive variable signal curve 51 while the valve device 16 executes an application. The application comprises, for example, the position control of the valve unit 1 and / or a control of the fluidic actuator 21, for example, a pressure control of the fluidic actuator and / or a position control of an actuator element 49 (for example, a piston) of the fluidic actuator 21. For example, the valve device 16 has the controller 50, which executes the application. The controller 50 is, for example, separate from the valve units 1 and is expediently communicatively connected to the valve units 1. In particular, the controller 50 provides a respective position setpoint signal 31 for each valve unit 1 within the scope of the application.

[0054] Preferably, the valve device 16, in particular the adaptation algorithm 28, checks whether one or more criteria for the opening point determination procedure are met and, in response thereto, begins the opening point determination procedure and expediently causes the provision of the drive variable signal curve 51. The criterion or the multiple criteria include, for example, that the valve unit 1 for which the opening point determination procedure is to be carried out is not currently required (in particular by the application) and / or does not currently have to assume the open state (within the scope of the application).

[0055] The valve device 16 preferably provides the drive variable signal waveform 51 when the application specifies the closed state for the valve member 6. When the drive variable signal waveform 51 is provided, the valve member 6 is expediently set to the open state briefly enough so that the application (which requires the closed state at this time) is not impaired. The valve device 16 expediently sets the valve member 6 to the closed state immediately after the drive variable signal waveform has been completed. For example, the adaptation algorithm 28 (particularly during the application) supplies the drive variable signal waveform signal 43 to the drive variable controller 29 instead of the drive variable setpoint signal 33 (which is particularly determined by the application).Expediently, immediately after the completion of the drive variable signal curve, the adaptation algorithm 28 again feeds the drive variable setpoint signal 33 to the drive variable controller 29 and no longer the drive variable signal curve signal 43.

[0056] By way of example, the valve device 16 comprises the first valve unit 1A and the second valve unit 1B (which is expediently designed identically to the first valve unit 1A). The second valve unit 1B is assigned to the same working outlet—exemplarily the first working outlet 19—as the first valve unit 1A. Expediently, the valve device 16 provides the drive variable signal curve 51 (which causes the valve member 6 of the first valve unit 1A to move from the closed state to the open state) when the valve member of the second valve unit 1B is in the open state. For example, the valve device 16 provides the drive variable signal curve 51 for the first valve unit 1A when pressurized fluid is discharged from the first working outlet via the second valve unit 1B (exemplarily into the fluid sink 18).Conveniently, the valve device 16 provides the drive variable signal waveform 51 (which causes the valve member 6 of the second valve unit 1B to move from the closed state to the open state) when the valve member of the first valve unit 1A is in the open state. For example, the valve device 16 provides the drive variable signal waveform 51 for the second valve unit 1B when pressurized fluid is supplied to the first working outlet 19 via the first valve unit 1A (exemplarily from the fluid source 17).

[0057] In particular, the valve device 16 detects that the first valve unit 1A is in the open state and, in response thereto, provides the drive quantity signal waveform 51 for the second valve unit 1B and / or detects that the second valve unit 1B is in the open state and, in response thereto, provides the drive quantity signal waveform 51 for the first valve unit 1A.

[0058] The first valve unit 1A and the second valve unit 1B are fluidically connected to the first pressure chamber 22 via the first working outlet 19. For example, pressurized fluid is admitted into the first pressure chamber 22 via the first valve unit 1A, and pressurized fluid is discharged from the first pressure chamber 22 via the second valve unit 1B. According to an alternative embodiment, compressed air is discharged from the first pressure chamber via the first valve unit, and compressed air is admitted into the first pressure chamber via the second valve unit.

[0059] During the application, for example, a pressure in a volume—for example, the first pressure chamber 22—is regulated. For this purpose, the first valve unit 1A functions, for example, as a venting valve and the second valve unit 1B as a venting valve. Expediently, during the application, only one of the two valve units 1A, 1B—i.e., either the first valve unit 1A or the second valve unit 1B—is in the open position, and the other valve unit is in the closed position. Preferably, the valve device 16 performs the respective opening point determination procedure for the valve unit 1 that is currently in the closed state.

Claims

[1] Method for determining an opening point position value (39) of a valve device (16) with a valve unit (1) which is designed as a piezo valve unit, wherein the opening point position value (39) describes the position of a valve member (6) of the valve unit (1) at which the valve member (6) changes from a closed state to an open state, the method comprising the steps: - Providing a drive variable signal curve (51), in particular a drive variable ramp, in order to drive the valve member (6) with a drive variable, namely an electrical voltage, so that the valve member (6) is moved from the closed state to the open state and / or from the open state to the closed state, - while providing the drive variable signal curve (51), recording a position characteristic curve (36) of the valve member (6) as a function of the drive variable, - on the basis of the recorded position characteristic curve (36), determining the opening point position value (39), wherein the valve device (16) carries out a position control of the valve member (6) using the opening point position value (39). [2] Method according to claim 1, wherein the valve device (16) has an elastic sealing element (8) against which the valve member (6) rests in the closed state, and wherein the valve member (6) is pressed into the elastic sealing element (8) by an initial value (37) of the drive variable signal curve (51), so that the valve member (6) undergoes a first movement phase during the provision of the drive variable signal curve (51), in which the valve member (6) moves in the direction of the open state, while the valve member (6) continues to rest against the elastic sealing element (8) and is in the closed state, and a second movement phase following the first movement phase, in which the valve member (6) is in the open state. [3] Method according to claim 2, wherein the position characteristic curve (36) has a first characteristic curve section (41) which is assigned to the first movement phase, and a second characteristic curve section (42) which is assigned to the second movement phase, and the valve device (16) determines a position value of the valve member (6) at a kink (44) between the first characteristic curve section (41) and the second characteristic curve section (42) as the opening point position value (39). [4] Method for determining an opening point position value (39) of a valve device (16) with a valve unit (1), in particular a piezo valve unit, wherein the opening point position value (39) describes the position of a valve member (6) of the valve unit (1) at which the valve member (6) changes from a closed state to an open state, the method comprising the steps: - Providing a drive variable signal curve (51), in particular a drive variable ramp, in order to drive the valve member (6) with a drive variable, in particular an electrical voltage or a pressure, so that the valve member (6) is moved from the closed state to the open state and / or from the open state to the closed state, - while providing the drive variable signal curve (51), recording a position characteristic curve (36) of the valve member (6) as a function of the drive variable, - on the basis of the recorded position characteristic curve (36), determining the opening point position value (39), wherein the valve device (16) carries out a first rotation of the recorded position characteristic curve (36) by means of a mathematical operation in order to obtain a rotated position characteristic curve (47), and determines the opening point position value (39) by detecting a minimum (46) of the rotated position characteristic curve (47). [5] Method according to claim 4, wherein the valve device (16) performs a second rotation of the minimum (46) opposite to the first rotation in order to determine the opening point position value (39). [6] Method according to claim 4, wherein the valve device (16) performs a position control of the valve member (6) using the opening point position value (39). [7] Method for determining an opening point position value (39) of a valve device (16) with a valve unit (1), in particular a piezo valve unit, wherein the opening point position value (39) describes the position of a valve member (6) of the valve unit (1) at which the valve member (6) changes from a closed state to an open state, the method comprising the steps: - Providing a drive variable signal curve (51), in particular a drive variable ramp, in order to drive the valve member (6) with a drive variable, in particular an electrical voltage or a pressure, so that the valve member (6) is moved from the closed state to the open state and / or from the open state to the closed state, - while providing the drive variable signal curve (51), recording a position characteristic curve (36) of the valve member (6) as a function of the drive variable, - on the basis of the recorded position characteristic curve (36), determining the opening point position value (39), wherein the drive variable signal curve (51) is provided while the valve device (16) is executing an application, wherein the drive variable signal curve (51) is provided when the application specifies the closed state for the valve member (6). [8] Method according to any preceding claim, wherein the valve unit (1) is a first valve unit (1A) and the valve device (16) comprises a second valve unit (1B) which is assigned to the same working output (19) as the first valve unit (1A), and the valve device (16) provides the drive variable signal curve (51) for the first valve unit (1A) when a valve member (6) of the second valve unit (1B) is in an open state. [9] Method according to claim 8, wherein the first valve unit (1A) and the second valve unit (1B) are pneumatically connected to a pressure chamber (22) via the working outlet (19), and wherein pressure fluid is admitted into the pressure chamber (22) via the first valve unit (1A) and pressure fluid is discharged from the pressure chamber (22) via the second valve unit, or wherein pressure fluid is discharged from the pressure chamber (22) via the first valve unit and pressure fluid is admitted into the pressure chamber (22) via the second valve unit (1B). [10] Method according to any preceding claim, wherein the valve device (16) for recording the position characteristic curve (36) detects the position of the valve member (6) using a magnetic field sensor and a magnet (15) present on the valve member (6). [11] Valve device (16) with a valve unit (1) designed as a piezo valve unit and having a valve member (6) that can be moved from a closed state to an open state by means of a drive variable, namely an electrical voltage, wherein the valve device (16) is designed to provide a drive variable signal curve (51) to drive the valve member (6) so that the valve member (6) is moved from the closed state to the open state and / or from the open state to the closed state, while providing the drive variable signal curve (51), to record a position characteristic curve (36) of the valve member (6) as a function of the drive variable, and to determine an opening point position value (39) on the basis of the recorded position characteristic curve (36), wherein the opening point position value (39) describes the position of the valve member (6) at which the valve member (6) transitions from the closed state to the open state,wherein the valve device (16) is designed to perform a position control of the valve member (6) using the opening point position value (39). [12] Valve device (16) according to claim 11, wherein the valve device (16) is designed to carry out a method according to one of claims 1 to 3.

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