Method for operating a valve device, valve device and data storage medium with a computer program

Abstract

A method for operating a valve device for supplying compressed air to compressed air consumer includes the steps of: determination of a first fluid pressure in a first section of a fluid passage of a valve assembly, which extends between an inlet port, and a valve element, determination of a second fluid pressure in a second section of the fluid passage of the valve assembly, which extends between the valve element and an outlet port, determination of a flow value for the valve element from the two fluid pressures and of a flow function, relating of the flow value with a presettable volumetric fluid flow rate or mass fluid flow rate for the pressurised fluid, which flow rate is provided for flow through the fluid passage, to a guide value and determination of a required actuating energy for an actuating device, and provision of the actuating energy to the actuating device.

Claims

1. A method for operating a valve device for supplying compressed air to compressed air consumer, the method comprising the steps of: determination of a first fluid pressure in a first section of a fluid passage of a valve assembly, which extends between an inlet port which is provided for a fluidically communicating connection to a fluid source or a fluid sink, and a valve element, determination of a second fluid pressure in a second section of the fluid passage of the valve assembly, which extends between the valve element and an outlet port which is provided for a fluidically communicating connection to a compressed air consumer, determination of a flow value for the valve element from the two fluid pressures and of a flow function, relating of the flow value with a presettable volumetric fluid flow rate or mass fluid flow rate for the pressurised fluid, which flow rate is provided for flow through the fluid passage, to a guide value and determination of a required actuating energy for an actuating device which is designed for an actuation of the valve element, provision of the actuating energy to the actuating device for adjusting the presettable volumetric fluid flow rate or mass fluid flow rate, wherein the flow value is determined from the flow function set in relation to a quotient of the first fluid pressure and the second fluid pressure, and wherein the actuating energy is determined on the basis of the guide value and of a valve characteristic.

2. The method according to claim 1, wherein two independently controllable valve assemblies are provided, their respective second sections of the respective fluid passages being connected to a common outlet port and their inlet ports being connected to different fluid sources or fluid sinks, wherein one of the two valve assemblies is selectively controlled as a function of a pressure differential between the respective inlet port and the common outlet port and of the presettable volumetric fluid flow rate or mass fluid flow rate.

3. The method according to claim 2, wherein the compressed air consumer has two fluidically separated, kinematically coupled operating chambers, and wherein and that each of the operating chambers is assigned two independently controllable valve assemblies, their respective second sections of the respective fluid passages being connected to a common outlet port and their respective inlet ports being connected to different fluid sources or fluid sinks, and wherein the two operating chambers are synchronously supplied with compressed air with presettable volumetric fluid flow rates by selective control of the respective valve assemblies.

4. The method according to claim 3, wherein a first volumetric fluid flow rate or mass fluid flow rate is preset for a first operating chamber of the compressed air consumer and a second volumetric fluid flow rate or mass fluid flow rate is preset for a second operating chamber of the compressed air consumer in order to obtain a movement profile for the connected compressed air consumer, and/or wherein a first pressure pattern profile is preset for the first operating chamber and a second pressure pattern profile is preset for the second operating chamber.

5. A valve device for operating a compressed air consumer, with a valve assembly in which a fluid passage is formed between an inlet port for a fluidically communicating connection to a fluid source or fluid sink and an outlet port for a fluidically communicating connection to a compressed air consumer, and with a valve element which is located movably in the fluid passage for influencing a cross-section of the fluid passage and which is assigned an actuating device for changing a functional position, and with a processing device for a provision of actuating energy to the actuating device, wherein a first pressure sensor is assigned to a first section of the fluid passage between the inlet port and the valve element and a second pressure sensor is assigned to a second section of the fluid passage between the valve element and the output port and wherein the processing device is designed for an execution of the following steps: determination of a first fluid pressure in the first section of the fluid passage, determination of a second fluid pressure in the second section, determination of a flow value for the valve element from the two fluid pressures and of a flow function, relating of the flow value with a presettable volumetric fluid flow rate or mass fluid flow rate for the pressurised fluid to a guide value and determination of a required actuating energy for an actuating device which is designed for an actuation of the valve element, provision of the actuating energy to the actuating device for adjusting the presettable volumetric fluid flow rate or mass fluid flow rate and wherein the processing device is designed for a determination of the flow value from the flow function set in relation to a quotient of the first fluid pressure and the second fluid pressure and for a determination of the actuating energy on the basis of the guide value and of a valve characteristic.

6. The valve device according to claim 5, wherein two independently controllable valve assemblies are provided, their respective second sections of the respective fluid passages being connected to a common outlet port and their inlet ports being connected to different fluid sources or fluid sinks, and wherein the processing device is designed for a selective controlled of one of the two valve assemblies as a function of a pressure differential between the respective inlet port and the common outlet port and of the presettable volumetric fluid flow rate or mass fluid flow rate.

7. The valve device according to claim 6, wherein the valve device is designed as a proportional valve.

8. The valve device according to claim 7, wherein the valve device is designed as a fluidically pilot-controlled proportional valve.

9. The valve device according to claim 5, wherein the processing device is connected to two pairs of two independently controllable valve assemblies each, the second section of each of the respective fluid passages being connected in pairs to a common outlet port and a first inlet port of each pair being connected to a fluid source and a second inlet port of each pair being connected to a fluid sink, and wherein the processing device is designed for a synchronous compressed air supply of the two operating chambers with presettable volumetric fluid flow rates by optional control of the respective valve assemblies.

10. A data storage medium with a computer program designed for storage in a processing device of a valve device and, if executed in a processor of the processing device, inducing a method comprising the steps of: determination of a first fluid pressure in a first section of a fluid passage of a valve assembly, which extends between an inlet port which is provided for a fluidically communicating connection to a fluid source or a fluid sink, and a valve element, determination of a second fluid pressure in a second section of the fluid passage of the valve assembly, which extends between the valve element and an outlet port which is provided for a fluidically communicating connection to a compressed air consumer, determination of a flow value for the valve element from the two fluid pressures and of a flow function, relating of the flow value with a presettable volumetric fluid flow rate or mass fluid flow rate for the pressurised fluid, which flow rate is provided for flow through the fluid passage, to a guide value and determination of a required actuating energy for an actuating device which is designed for an actuation of the valve element, provision of the actuating energy to the actuating device for adjusting the presettable volumetric fluid flow rate or mass fluid flow rate, wherein the flow value is determined from the flow function set in relation to a quotient of the first fluid pressure and the second fluid pressure, wherein the actuating energy is determined on the basis of the guide value and of a valve characteristic.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Advantageous embodiments of the invention are illustrated in the drawing, of which:

(2) FIG. 1 is a diagrammatic representation of a first embodiment of a fluidic system with a valve device and a compressed air consumer having two kinematically coupled operating chambers,

(3) FIG. 2 is a diagrammatic representation of a second embodiment of a fluidic system with a valve device comprising a valve element and with a compressed air consumer having one operating chamber, and

(4) FIG. 3 is a diagrammatic representation of a third embodiment of a fluidic system with a valve device comprising two valve elements and with a compressed air consumer having one operating chamber.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(5) The fluidic system 1 shown in FIG. 1 is, merely by way of example, designed for providing a linear movement and for this purpose comprises a valve device 2 and a compressed air consumer 3. In the illustrated embodiment, the valve device 2 is implemented as a pneumatic full-bridge circuit with a total of four valve elements 4, 5, 6 and 7 designed as 2/2-way proportional valves, each of the valve elements 4, 5, 6 and 7, merely by way of example, being designed as a solenoid valve with a solenoid drive 8, 9, 10 and 11 as actuating device. In an alternative embodiment not shown in detail, the actuating device can be designed as a piezoelectric, magnetostriction or otherwise suitable drive.

(6) Each of the valve elements 4, 5, 6 and 7 can be switched between two functional positions, in particular a closed-centre position and an open position, if electric energy is suitably applied to the associated solenoid drives 8, 9, 10 and 11. For this purpose, the solenoid drives 8, 9, 10 and 11 are electrically connected via control lines 15, 16, 17 and 18 to a processing device 19, which forms a part of the valve device 2 and comprises a microprocessor or microcontroller by way of example.

(7) Each of the valve elements 4, 5, 6 and 7 is connected to fluidic nodes 28 to 31 via associated fluid lines 20 to 27, forming a valve assembly not designated in detail together with the fluid lines 20 to 27, which are assigned in pairs. The fluid lines 20 to 23 are in each case described as the first section of a fluid passage of the respective valve element 4, 5, 6 and 7. The fluid lines 24 to 27 are, on the other hand, described as the second section of a fluid passage of the respective valve element 4, 5, 6 and 7. The fluid lines 20 and 21 jointly terminate at a fluidic node 28, the fluid lines 22 and 23 jointly terminate at a fluidic node 30, the fluid lines 24 and 25 jointly terminate at a fluidic node 29, and the fluid lines 26 and 27 jointly terminate at a fluidic node 31.

(8) Merely by way of example, the fluidic node 28 is connected to a fluid source 32 via a supply line 36, while the fluidic node 30 is connected via an exhaust air line 37 to a fluid outlet to which a silencer 33 is assigned. The fluidic node 29 forms a first operating port of the valve device 2 and is connected to a fluid port 39 of the compressed air consumer 3 via a first connecting line 38, while the fluidic node 31 forms a second operating port of the valve device 2 and is connected to a fluid port 41 of the compressed air consumer 3 via a second connecting line 40.

(9) Merely by way of example, it is provided that a pressure sensor 42 to 45 designed in each case for a detection of the respective fluid pressure in the associated line 36, 37, 38 and 40 and for a provision of a pressure-dependent sensor signal to the processing device 19 via an associated sensor line 46 to 49 is assigned to the supply line 36, the exhaust air line 37, the first connecting line 38 and the second connecting line 40. In an embodiment not shown in detail, at least one of the pressure sensors is located in a housing for a valve device or outside such a housing.

(10) Merely by way of example, the compressed air consumer 3 is designed as a double-acting pneumatic cylinder in which there is accommodated in a cylinder recess 51 of a cylinder housing 52 an operating piston 50also described as a movable wallcapable of linear movement and separating a first variable-size operating chamber 53 from a second variable-size operating chamber 54. In the illustrated embodiment, the operating piston 50 is connected to a piston rod 55, which passes through the end face of the cylinder housing 52 and, together with the operating piston 50, can be displaced relative to the cylinder housing 52 along a straight path.

(11) Merely by way of example, it will be described below which steps are required in the fluidic system 1 in order to induce a movement of the operating piston 50 together with the coupled piston rod 55 in accordance with a presettable movement profile. In this example, the operating piston 50 is to be moved, starting from the position shown in FIG. 1, in such a way that an end face of the operating piston 50 comes into contact with an inner surface 58 of the cylinder housing 52, which is located opposite. In this example, the presettable movement profile is designed such that it starts with a constant acceleration of the operating piston 50 to a presettable target speed, followed by a constant movement of the operating piston while maintaining the target speed and finally a deceleration of the operating piston 50 to vanishingly low speed.

(12) For the planned movement of the operating piston 50, a supply of pressurised fluid to the operating chamber 54 is required, while a discharge of fluid from the operating chamber 53 has to be provided. In order to obtain the desired movement profile, the provision of presettable volumetric fluid flow rates is expedient, because this allows the speed of movement for the operating piston to be adjusted precisely. Accordingly, a control of the valve element 4 and the valve element 6 has to be provided for, wherein a fluidically communicating connection between the fluid source 32, the fluidic node 29 and the second fluid port 39 is established via the valve element 4 and a fluidically communicating connection between the first fluid port 41, the fluidic node 31 and the fluid outlet with the silencer 33 is established via the valve element 6.

(13) In order to be able to move the operating piston 50 in accordance with the movement profile described above, the processing device 19 first identifies the sensor signals of the pressure sensors 42 to 45 in order to be able to calculate the pressure ratios across the two valve elements 4 and 6. Using these pressure ratios, a flow value can be determined in a following step in the processing device 19 for each of the valve elements 4, 6 from the two fluid pressures and a flow function. The respectively determined flow value is then related to a presettable volumetric fluid flow rate or mass fluid flow rate which has to be provided to the respective operating chamber 53, 54 in order to obtain the desired movement of the operating piston 50 in accordance with the movement profile. The result of this relation is described as guide value and is required for determining a required actuating energy for the respective solenoid drive 8, 10. The actuating energy for each solenoid drive 8, 10 is determined by relating the guide value to a valve characteristic which is determined experimentally in particular. The actuating energy is then made available to the respective solenoid drives 8, 10 and there results in a movement of the respective valve spools (not designated in detail) of the respective valve elements 4, 6 and thus enables a fluidically communicating connection between the respective fluidic nodes 28 and 29 and/or 31 and 30.

(14) The control of the respective valve elements 4, 6 results in a volumetric fluid flow rate or mass fluid flow rate between the fluid source 32 and the operating chamber 54 and between the operating chamber 53 and the silencer 33 which goes along with a change of the pressures in the respective fluid lines 20 to 27. By means of a cyclically repeated determination of the sensor signals of the pressure sensors 42 to 45 and the subsequent processing of the pressure ratios in accordance with the above procedure, the processing unit 19 can adjust the volumetric fluid flow rates for the two operating chambers 53, 54 of the compressed air consumer 3 in such a way that the desired movement profile for the operating piston 50 is maintained.

(15) The embodiments of fluidic systems 61 and 91 shown in FIGS. 2 and 3 differ from the fluidic system 1 according to FIG. 1 in that the compressed air consumer 63 ismerely by way of exampledesigned as a single-acting pneumatic cylinder, so that only one operating chamber 65 is formed in the respective cylinder housing 64.

(16) In the embodiment according to FIG. 2, the valve device 62 is by way of example designed as a proportional 3/3-way valve in which, in the switching position shown, which can also be described as inoperative or neutral position, fluidically communicating connections between a fluid source 66, an operating port 67 and a fluid outlet 68 with silencer are blocked. The valve spool 69 of the valve device 62 can be moved into two different functional positions with the aid of the associated solenoid drives 70, 71. In the first functional position, a fluidically communicating connection is established between the fluid source 66 and the operating chamber 65. In the second functional position, a fluidically communicating connection is established between the operating chamber 65 and the fluid outlet 68. The processing device 72 is designed in the same way as the processing device 19 of FIG. 1 and thus facilitates, using sensor signals of the pressure sensors 73, 74, 75, a provision of presettable volumetric fluid flow rates into and out of the operating chamber 65.

(17) In the embodiment according to FIG. 3, the valve devices 92 are designed as proportional 2/2-way valves 100, 101 with valve spools 99 as valve elements and can be controlled individually by the associated processing device 102 for an optional provision of pressurised fluid from the fluid source 66 into the operating chamber 65 or from the operating chamber 65 to the fluid outlet 68. The processing device 102 is designed in the same way as the processing device 19 of FIG. 1 and thus facilitates, using sensor signals of the pressure sensors 103, 104, 105, a provision of presettable fluid flow rates into and out of the operating chamber 65.