DE102021200204A1 - Fluidic actuator, system and method - Google Patents

Abstract

The invention relates to a fluidic adjusting device (10) for providing an adjusting movement (2), with a housing (12) on which a moving element (14) is arranged, the moving element (14) being arranged along an adjusting axis (1) relative to the housing ( 12); , a sensor arrangement (22) arranged on the housing (12) for detecting the magnetic field, the sensor arrangement (22) having a counting sensor unit (26) which is provided for a counting process of the characteristic magnetic field points (20) during the positioning movement, the counting sensor unit (26) together with the magnet unit (16) forms a domain wall generator (29).

Description

The invention relates to a fluidic actuating device for providing an actuating movement, having a housing on which a moving member is arranged, the moving member being positionable along an adjusting axis relative to the housing, a magnet unit providing a magnetic field, which is arranged on the moving member, the magnetic field has characteristic magnetic field points spaced apart from one another along the adjustment axis, and a sensor arrangement arranged on the housing for detecting the magnetic field.

One object of the invention is to provide a fluidic actuating device that enables a reliable determination of a position of the moving member.

The object is achieved by a fluidic control device according to claim 1. Advantageous developments are specified in the dependent claims.

In the case of the fluidic actuating device, the sensor arrangement has a counting sensor unit which is designed to determine a counting value by counting the characteristic magnetic field points during the actuating movement. Together with the magnet unit, the counting sensor unit forms a domain wall generator.

The counting process can preferably be carried out with the domain wall generator in particular in the electrically voltage-free state of an evaluation device. By using the domain wall generator, the position of the moving element can be determined even though the fluidic actuating device, the sensor arrangement and/or the evaluation device are electrically voltage-free. The voltage-free state is established, for example, when a connection to a voltage source is interrupted. If the moving element is moved, for example by hand, along the actuating axis when the fluidic actuating device, the sensor arrangement and/or the evaluation device is in a voltage-free state, the domain wall generator can advantageously continue the counting process and after the electrical voltage has been restored, the position can be determined by the evaluation device will. Thanks to the domain wall generator, the counting process can be continued without gaps despite an interruption in the power supply.

The sensor arrangement advantageously has an increment sensor unit, by means of which an increment between a characteristic magnetic field point and the increment sensor unit can be determined in order to determine the increment of the position of the moving element. The increment can be understood to mean a distance, in which case in particular the distance can be understood starting from a characteristic magnetic field point.

The increment can be determined by two magnetic sensors offset by 90° from one another and integrated in the increment sensor unit, so that two signals originating from the increment sensor unit are obtained, which stand for a sine component or a cosine component of the magnetic field. The sine components and cosine components can be evaluated by the evaluation device using a calculation based on arctan2.

The increment sensor unit preferably measures an increment starting from a characteristic magnetic field point, it being possible for the increment to be smaller than or not larger than a distance formed between two adjacent characteristic magnetic field points. The increment can be measured using a magnetic field curve between two adjacent characteristic magnetic field locations.

A particular embodiment can include that the counting sensor unit has a giant magnetoresistive layer stack, which together with the magnet unit form the domain wall generator. The layer stack can have a linear, helical, meandering, wavy and/or spiral structure, which can be obtained in particular by micromechanical technologies. The layer stack can preferably be integrated in the counting sensor unit. The magnetic field of the magnet unit can interact with the layer stack and generate a domain wall in the layer stack that is formed in accordance with the actuating movement.

This domain wall generated in the layer stack can be generated in particular when the actuating device, the sensor arrangement and/or the evaluation device are in an electrically voltage-free state. As a result, the counting process with the domain wall generator can be carried out in the electrically voltage-free state of the evaluation device.

In an advantageous development, the magnetic unit can be designed as a magnetic tape which is arranged on a longitudinal section of the moving element aligned along the adjustment axis, with the counting sensor unit being able to be assigned a fixed counting reference point on the magnetic unit. The adjusting axis is designed in particular in such a way that a linear adjusting movement is carried out by the Movement member is running. The longitudinal section performs an adjustment movement relative to the sensor arrangement. The counting reference point represents a reference point from which the counting process of the counting sensor unit can be started. For example, the counting process can start at the count value=0, with the count value being increased by a whole number for each characteristic magnetic field point counted during an increasing movement aligned along the adjustment axis. During the increase movement, the count value is increased by the evaluation unit and/or the sensor arrangement, independently of the initial value.

In the case of a decrease movement, which is aligned in the opposite direction to the increase movement with respect to the adjustment axis, the count value for each characteristic magnetic field point counted is reduced by a whole number by the evaluation unit and/or the sensor arrangement. In this way, the positioning of the moving element along the adjustment axis can be determined unambiguously. The adjustment movement can be represented by the increase movement or the decrease movement. In the fluidic actuating device according to the invention, there is no need for a multiple design of the magnet unit, so that a single-track magnet unit is sufficient to obtain an absolute position value of the moving element through the evaluation with the evaluation device.

For example, the fluidic actuating device can be designed as a fluid actuator, wherein the housing can be a fluid cylinder housing, the moving element can be a fluid piston and/or the longitudinal section can be a piston rod. The piston rod extends along the adjustment axis and has the magnet unit, which is preferably designed as a magnetic strip. The fluid cylinder housing contains the sensor arrangement and a preferably wired connection to the evaluation device. Furthermore, the fluid cylinder housing has fluid lines that can be connected to a valve device, so that the fluidic actuating device can be acted upon by a pressure medium. The pressure medium is preferably compressed air and the fluid actuator is a pneumatic cylinder. The fluidic adjusting device is in particular a pneumatic drive cylinder.

Preferably, the distances between two adjacent characteristic magnetic field points can be the same in each case. The equally large distances preferably result from a periodic magnetic field profile along the adjustment axis. The magnet assembly may have oppositely polarized magnetic poles equidistant from each other on a surface providing a magnetic field. The magnetic poles are referred to as north poles and south poles and produce a magnetic flux which exemplarily exits the north poles and enters the south poles. This results in a local magnetic field profile which, outside the magnet unit, has a magnetic field direction running from the north pole to the south pole. A maximum of a magnetic field line of the magnetic field profile is thus formed outside the magnet unit between the north poles and south poles. A minimum of such a magnetic field line is formed at each of the magnetic poles. Such a periodic magnetic field can preferably have a wave-shaped magnetic field profile.

The minima and/or the maxima can be used as characteristic magnetic field locations. Here, the characteristic magnetic field points can be indexed with an integer value.

The counting sensor unit and the incremental sensor unit can preferably be adjacent to one another in the direction of the adjustment axis. The distance between the counting sensor unit and the incremental sensor unit along the adjustment axis can be compensated for by the evaluation device, in particular by an algorithm. In an alternative embodiment of the sensor arrangement, the counting sensor unit and the incremental sensor unit can be positioned at the same height with respect to the adjustment axis. The counting sensor unit can be arranged on a first side and the incremental sensor unit on a second side next to the adjustment axis at the same height, with the first and the second side being arranged on different sides with respect to the adjustment axis. In a further alternative, the counting sensor unit and the incremental sensor unit can be arranged one above the other in the radial direction with respect to the adjustment axis. Due to the advantageous arrangement of the counting sensor unit and the incremental sensor unit, the entire sensor arrangement can be brought very close to the magnetic field, so that only low magnetic field strengths are necessary for an unambiguous detection of the magnetic field.

The sensor arrangement can be arranged on a printed circuit board, with at least the counting sensor unit and the incremental sensor unit being mounted on the printed circuit board. The sensor assembly may be fixedly attached to a housing inner surface immediately opposite a mover outer surface on which the magnet assembly is located. The inner surface of the housing is arranged on an inner side of the housing of the actuating device. A recess in which the sensor arrangement is arranged is formed in a wall of the housing. The recess extends from a housing outer surface to the housing inner surface. The mover outer surface faces proximate the housing inner surface so that the sensor assembly faces directly the mover outer surface. This ensures that the magnetic field can be detected accurately and robustly. The mover outer surface extends along the adjustment axis on the longitudinal section. In a fluid actuator, the mover outer surface is the outer peripheral surface of the piston rod.

The invention also relates to a system with a fluidic actuating device according to the invention, the sensor arrangement being connected to an evaluation device, the evaluation device being designed to determine a position of the moving element using sensor signals from the sensor arrangement.

In order to use the sensor arrangement to determine a position of the moving member relative to the housing that is assumed by the adjusting movement, a method can be carried out which carries out a counting process. During the counting process, the characteristic magnetic field points of the magnetic field are counted, with the counting process taking place starting from the counting reference point during the positioning movement. Furthermore, an increment determination is carried out to determine the position of the mover between two adjacent characteristic magnetic field locations. From the sensor signals of the counting process and the determination of the increment, the absolute position value is determined by an evaluation step by the evaluation device. The absolute position value relates to the counting reference point of the moving element. The determination of the absolute position value may be calculated using a microprocessor in conjunction with a memory and an algorithmic calculation based on the count and the increment.

A preferred development includes the advantageous calculation of the absolute position value by multiplying the counted value by the distance between adjacent characteristic magnetic field points. The increment can be added to or subtracted from the product obtained from the multiplication. Here, the increment is measured starting from the characteristic magnetic field points last counted.

The distance between two characteristic magnetic field points can be stored in the memory of the evaluation device. Saving the distance is particularly useful when each distance between adjacent characteristic magnetic field points is identical. Alternatively, the distance can be measured by the incremental sensor unit, preferably during the adjustment movement, with this alternative proving to be particularly advantageous when the distances between characteristic magnetic field points are at least partially different in size.

According to the method, the count value can be obtained from the counting process when the fluidic actuating device is in an electrically voltage-free state, so that the position of the actuating device can be reliably determined in the event of power failures.

Advantageously, the correction of the absolute position value is carried out by a main controller, which in particular contains the evaluation device. In the main controller, the actual absolute position value is compared with a desired position value, with a preferably fluidic driver device being activated if the absolute position value deviates from the desired position value. Due to the activation of the driver device, the moving element executes an actuating movement, so that the difference between the absolute position value and the position setpoint is corrected. The driver device can in particular be a valve device.

• 1 einen Längsschnitt durch eine fluidische Stellvorrichtung entlang einer Stellachse,
• 2 eine schematische Darstellung eines Magnetfeldverlaufs einer Magneteinheit der fluidischen Stellvorrichtung,
• 3 einen schematischen Schaltplan eines fluidischen Systems mit der fluidischen Stellvorrichtung und einer Ventileinrichtung, und
• 4 ein schematisches Ablaufdiagramm eines durch die Stellvorrichtung ausgeführten Verfahrens.

The invention is explained in more detail below with reference to the accompanying drawings. These show in

• 1 a longitudinal section through a fluidic actuating device along an actuating axis,
• 2 a schematic representation of a magnetic field profile of a magnet unit of the fluidic actuating device,
• 3 a schematic circuit diagram of a fluidic system with the fluidic actuating device and a valve device, and
• 4 a schematic flowchart of a method executed by the actuating device.

In 1 shows a longitudinal section through a fluidic actuating device 10 along an actuating axis 1, which is used to provide an actuating movement 2. The fluidic actuating device 10 has a housing 12 on which a moving member 14 is arranged, with the moving member 14 preferably being movably mounted within the housing 12 . The movement member 14 can be positioned along the adjustment axis 1 relative to the housing 12 by the adjustment movement 2 . A magnet unit 16 providing a magnetic field 15 is attached to the movement transmission member 14 arranged. A magnetic field curve of the magnetic field 15 is in 2 shown.

The magnetic unit 16 is preferably designed as a magnetic strip 17 which is arranged on a longitudinal section 32 extending along the adjustment axis 1 . The magnetic tape 17 extends parallel to the adjustment axis 1.

At a according 1 In the exemplary embodiment shown, the fluidic actuating device 10 can be designed as a fluid actuator 33 . The fluid actuator 33 has a housing 12 which includes a housing cylinder 13 . The housing cylinder 13 has a cavity 35 in which the moving member 14 is located. The moving element comprises a fluid piston 19 and the longitudinal section 32 designed as a piston rod 37. The piston rod 37 extends along the actuating axis 1.

At one axial end of the housing cylinder 13 there is a closing arrangement 31 through which the piston rod 37 is guided out of the cavity 35 . The actuating movement 2 allows the piston rod 37 to be moved out of the fluid cylinder housing 13 and retracted. The fluid actuator 33 is operated by a pressure medium, which is preferably compressed air, the fluid actuator 33 being in particular a pneumatic cylinder.

The closure assembly 31 includes a seal 39 bearing on a housing inner surface 34 which bears on a mover outer surface 36 . The cavity 35 is sealed off in a fluid-tight manner from the environment of the fluid actuator 33 by the seal 39 .

The magnet unit 16 embodied as a magnetic tape 17 , for example, can be arranged in an elongate magnet receptacle formed parallel to the actuating axis 1 on the outer surface 36 of the moving member. An elongate cover 43 is arranged on the magnetic tape 17 arranged in the magnet receptacle and is flush with the rest of the mover outer surface 36 . The magnet unit 16 is preferably attached to the moving member 14 in a stationary manner.

A sensor arrangement 22 which is used to detect the magnetic field 15 is arranged on the housing 12 . The sensor arrangement 22 is connected to an evaluation device 24 . The evaluation device 24 is used to determine an absolute position of the moving element 14 with respect to the housing 12 using sensor signals from the sensor arrangement 22 .

The sensor arrangement 22 is arranged in a recess 11 in a wall of the housing 12 by means of a sensor seal 23 . The recess 11 extends from an outer surface of the housing of the fluidic actuating device 10 to the inner surface 34 of the housing, with part of the recess 11 being formed in the closing arrangement 31 . The sensor seal 23 seals the recess 11 in a fluid-tight manner from the environment. The recess 11 opens out on the inner surface 34 of the housing, with the sensor arrangement 22 inserted in the recess 11 protruding through the recess 11 into the cavity 35 .

The mover outer surface 36 faces the housing inner surface 34 directly. The sensor array 22 is aimed directly at the mover outer surface 36 so that the sensor array 22 can directly detect the magnetic field 15 . Only the cover 43 permeable to the magnetic field is arranged between the sensor arrangement 22 and the magnet unit 16 . The moving member outer surface 36 extending along the longitudinal section 32 represents the outer peripheral surface of the piston rod 37 in a fluid actuator 33.

The sensor arrangement 22 is preferably attached to the housing 12 in a stationary manner. The movement element 14 executes an adjustment movement 2 along the adjustment axis 1 relative to the sensor arrangement 22 . The adjusting movement 2 can be carried out as an increasing movement 3 along the adjusting axis 1 , with the moving member 14 being extended out of the housing 12 during the increasing movement 3 . A decrease movement 4 aligned opposite to the increase movement 3 causes the moving member 14 to be retracted into the housing 12 . In an exemplary fluid actuator 33, the piston rod 37 moves out of the cavity 35 of the fluid cylinder housing 13 during the increase movement 3, while the piston rod 37 moves into the fluid cylinder housing 13 during a decrease movement 3. The adjustment movement 2 is represented by the increase movement 3 and/or the decrease movement 4 .

The sensor arrangement 22 has a counting sensor unit 26 and an increment sensor unit 28 . The sensor assembly 22 may be mounted on a circuit board. The circuit board is located within the housing 12 with the count sensor unit 26 and the increment sensor unit 28 mounted on the circuit board so that they face the mover outer surface 36 with their sensitive portions.

The counting sensor unit 26 and the incremental sensor unit 28 are, for example, adjacent in the direction of the adjustment axis 1 on the inner top of the housing surface 34 arranged. The mover outer surface 36 is moved past the counting sensor unit 26 and the increment sensor unit 28 simultaneously during actuation movement 2 . The radial distance of the counting sensor unit 26 and the incremental sensor unit 28 to the moving element outer surface 36 is preferably the same in each case, the radial distance being aligned in a radial direction 5 with respect to the adjustment axis 1 . The counting sensor unit 26 is at a distance from the incremental sensor unit 28 along the adjustment axis 1, it being possible for the distance between the counting sensor unit 26 and the incremental sensor unit 28 to be compensated algorithmically by the evaluation device 24.

In a further exemplary alternative, the counting sensor unit 26 and the incremental sensor unit 28 can be arranged at approximately the same height on the housing inner surface 34 with respect to the adjustment axis 1 . In this case, the counting sensor unit 26 and the incremental sensor unit 28 are not spaced apart from one another along the adjustment axis 1 . In this exemplary alternative, the counting sensor unit 26 and the incremental sensor unit 28 can be arranged next to one another in a direction transverse to the adjustment axis 1 .

In 2 a schematic magnetic field course is shown, which originates from the magnet unit 16 . The magnet unit 16 is designed as a magnetic tape 17 in which magnetic poles 21 are contained. The direction of polarization between two opposite magnetic poles 21 forming a pair of poles is oriented perpendicularly to the adjustment axis 1 . A plurality of pole pairs consisting of a magnetic north and south pole are arranged in the magnetic tape 17 along the adjustment axis 1 . The pairs of poles are spaced apart from one another along the adjustment axis 1 by distances D of identical size. Adjacent pairs of poles have opposite polarization directions.

The magnetic field 15 generated by the magnet unit 16 is in 2 shown as an example as a wave-shaped magnetic field curve. The exemplary minima of the magnetic field profile represent the locations at which the magnet unit 16 has its magnet poles 21 and the magnetic field 15 enters and exits the magnet unit 16 . A maximum of the magnetic field profile is arranged between the minima, which are spaced apart from the surface of the magnetic tape 17 in the radial direction 5 . By way of example, a minimum of the magnetic field profile is assigned to the magnetic north poles and south poles. Neighboring magnetic poles 21 each have a minimum of the magnetic field profile. Due to the periodic course of the magnetic field, the minima each have the same distance D. The magnetic poles 21 also have the same distance D from one another along the adjustment axis 1 .

By way of example, the minima represent characteristic magnetic field points 20 which are spaced apart by the distance D from one another. In an embodiment not shown in the figures, the characteristic magnetic field points 20 could also be shown by maxima. The counting sensor unit 26 is used for a counting process 38 of the characteristic magnetic field points 20 during the positioning movement 2 . Here, the characteristic magnetic field points 20 can be indexed with an integer value Z, regardless of whether it is a maximum or a minimum. The indexing of the corresponding characteristic magnetic field points 20 can be determined in a memory of the evaluation device 24, in terms of circuitry by the sensor arrangement 22 and/or by the structure of the counting sensor unit 26.

A characteristic magnetic field point 20 is preferably selected as the counting reference point 30 . If the magnetic unit 16 is designed as a magnetic tape 17 , a fixed counting reference point 30 on the magnetic tape 17 can be assigned to the counting sensor unit 26 . The count reference point 30 can be understood as a reference point. The numerical value Z of the characteristic magnetic field point 20, which is assigned to the counting reference point 30, can be Z=0, for example.

The evaluation unit 24 can, in particular in conjunction with the counting sensor unit 26, carry out a counting process 38 which preferably relates to the counting reference point 30. The counting process 38 can be started by the counting sensor unit 26 . In particular, the counting process 38 starts at the count value Z=0. The counting process 38 increases the count value Z by a whole number for each characteristic magnetic field point 20 during the increase movement 3 along the setting axis 1 . The count value Z is increased by the evaluation unit 24 and/or sensor arrangement 22. The count value Z can assume values such as Z=0, Z=1, Z=2, Z=3, etc. Actuating movement 2 can start from a counter value Z that is higher than Z=0, so that during increment movement 3 the counter value Z is increased independently of the initial value.

During the decrease movement 4, the count value Z for each characteristic magnetic field point 20 is reduced by an integer. If, for example, the count value Z is increased to Z=4 by an increasing movement 3, the count value Z can be reduced by a decreasing movement 4 by two characteristic magnetic field points 20 to a count value Z=2. The reduction of the count Z is carried out by evaluation unit 24 and/or sensor arrangement 22.

The counting sensor unit 26 can have a giant magnetoresistive layer stack 45 which forms a domain wall generator 29 together with the magnet unit 16 . The layer stack can, for example, have a linear, helical, meandering, wavy and/or spiral structure, which can be obtained in particular by micromechanical production methods. In this case, the counting sensor unit 26 can be shorter, longer or of the same length as the magnet unit 16 along the adjustment axis 1 . The layer stack 45 can preferably extend along the adjustment axis 1 corresponding to the length of the counting sensor unit 26 . The layer stack 45 is preferably integrated in the counting sensor unit 26, so that in particular a monolithic electrical component is formed.

The magnetic field 15 of the magnet unit 16 interacts with the layer stack 45 so that a domain wall formed in accordance with the actuating movement 2 is generated in the layer stack 45 . This domain wall is generated in particular when the fluidic actuating device 10, the sensor arrangement 22 and/or the evaluation device 24 are in a voltage-free state. The voltage-free state is established, for example, when a connection to a voltage source is interrupted. The creation of the domain wall does not require any energy supplied from the outside, but is merely produced by the actuating movement 2 , the magnetic field 15 and the layer stack 45 .

The counting process 38 can be carried out by means of the domain wall generator 29 independently of a voltage state of the fluidic actuating device 10 , the sensor arrangement 22 and/or the evaluation device 24 . In this case, the domain wall generator 29 counts the numerical value Z, with the layer stack 45 being able to be connected up in terms of circuitry in such a way that an unambiguous count value Z, which is preferably related to the count reference point 30, is obtained.

The increment sensor unit 28 is used to determine an increment I. Starting from the characteristic magnetic field point 20, the increment I is measured preferably continuously along the magnetic course of the magnetic field 15. The increment I can be measured in the direction of the increasing movement 3 and/or in the direction of the decreasing movement 4, starting from a characteristic magnetic field point 20 . The increment I is located within the distance D between two characteristic magnetic field locations 20 . The increment I is preferably smaller or not larger than the distance D between two characteristic magnetic field points 20.

By measuring the increment sensor unit 28, an increment determination 41 of the position of the moving element 14 between two adjacent characteristic magnetic field points 20 is carried out. The increment determination 41 can be carried out by two magnetic sensors offset by 90° and integrated in the increment sensor unit 28 so that two signals originating from the increment sensor unit 28 are obtained which stand for a sine component or a cosine component of the magnetic field 15 . The sine component and cosine components can be evaluated by the evaluation device 24 using a calculation based on arctan2.

The absolute position value A is calculated by multiplying the counter value Z by the distance D and adding or subtracting the increment I to the value resulting from the multiplication of the counter value Z by the distance D. The increment I is measured starting from the characteristic magnetic field point 20 to which the count value Z determined last is assigned.

If, for example, an increase movement 3 from the count reference point 30 increases the count value Z to Z=4 starting with Z=0 and the increase movement 3 is not continued up to the count value Z=5, so that the sensor arrangement 22 is between the count values Z=4 and Z=5 comes to rest at the end of the increasing movement 3, then the increment I is measured starting from the characteristic magnetic field point 20 with the count value Z=4. The increment I has a positive sign and is added to the value measured between the count reference point 30 and the characteristic magnetic field point 20 with the count value Z=4.

In a decrease movement 4, the increment I is measured starting from the characteristic magnetic field point 20 with a higher count value Z in the direction of a characteristic magnetic field point 20 with a lower count value. The increment I from the measurement taken in the decrement movement has a negative sign because it must be subtracted from the higher count characteristic magnetic field location 20 to determine the correct position. In this case, for example, the counter value Z=4 is reduced by two characteristic magnetic field points 20 to a counter value Z=2. If the sensor arrangement 22 comes to rest between the characteristic magnetic field points 20 with the count values Z=1 and Z=2, then, starting from the characteristic magnetic field point 20 with the count value Z=2, the increment I in the direction of the next with a low be measured at the characteristic magnetic field point 20 provided with a lower counter value Z=1. The increment I thus obtained is subtracted from the value measured between Z=0 and Z=2 because of its negative sign.

The distance D between two characteristic magnetic field points 20 is preferably stored in a memory of the evaluation device 24 . Alternatively or additionally, the distance D can be measured in each case by the incremental sensor unit 28 , preferably during the positioning movement 2 .

The absolute position value A is calculated from the counter value Z, the distance D and the increment I according to the following formula, whereby the increment I can have a positive or a negative value depending on the positioning movement 3, 4: $$\text{A}=\text{Z}*\text{D}+\text{I}$$

In a preferred exemplary embodiment, a sensor system including sensor assembly 22 may be used. A software program stored in a memory and executed by a microprocessor can be provided with which the sensor signals are processed in such a way that the absolute position value A is obtained. The signals of the incremental sensor unit 26 and the counting sensor unit 26 generated by the sensor arrangement 22 can be executed by the microprocessor in order to determine the absolute position value A by multiplication, subtraction and addition of the sensor signals. The memory for the software program can be part of the evaluation device 24 .

the 3 shows a system 100 which has the fluidic actuating device 10 , a main control 49 and a driver device 40 . The main controller 49 is connected to the sensor assembly 22 through a signal line. The driver device 40 is connected to the main controller 49 via a control connection. The driver device 40 is connected to the actuating device 10 by a power line.

The adjusting device 10 can be a fluid actuator 33, which is designed in particular as a pneumatic cylinder. The main controller 49 can be a central controller that is part of a programmable logic controller, for example. The evaluation device 24 can be part of the main controller 49 . Alternatively or additionally, at least part of the main control 49 can be arranged directly on the actuating device 10 . The driver device 40 can in particular be a fluidic driver device 40 which is preferably embodied as a valve device 25 . The control connection can be a control line that transmits electrical control signals. The energy line can be formed by fluid channels that conduct a pressure medium to the fluid actuator 33 . The fluidic driver device 40 is connected to a pressure source and a pressure sink. The pressure medium can be compressed air. The entire system 100 is connected to an electrical voltage source.

The fluidic actuating device 10 has the domain wall generator 29 which is formed by the magnet unit 16 and the counting sensor unit 26 . The counting sensor unit 26 and the incremental sensor unit 28 are each aimed directly at the magnet unit 16 with a magnetically sensitive section. A position setpoint can be programmed into the main controller 49 . The actual absolute position value A, which is determined by the sensor arrangement 22 in conjunction with the evaluation device 24, is compared by the evaluation device 24 and/or the main controller 49 with the programmed desired position value. If there is a difference between the desired position value and the absolute position value A, the evaluation device 24 and/or the main controller 49 outputs a control command to the driver device 40 via the control connection. According to the control command, the driver device 40 causes the control device to carry out a positioning movement 2 that corrects the absolute position value A, so that after the correcting positioning movement 2 the absolute position value A matches the programmed desired position value.

In the case of a fluid actuator 33, the fluidic driver device 40 directs a pressure medium from the pressure source to the fluid actuator 33 and away from the fluid actuator 33 to the pressure sink. As a result, the fluid actuator 33 can perform a corrective actuating movement 2 and adapt its absolute position value A to the specified position setpoint.

A according 4 The flow chart shown for a method, which is provided for determining the absolute position value A, includes as a first step the counting process 38 of the characteristic magnetic field points 20 of the magnetic field 15 of the magnet unit 16 attached to the moving element 14. The counting process 38 starts from the counting reference point 30.

In a second step, the increment determination 41 of the increment I of the moving element 14 is carried out between two adjacent characteristic magnetic field points 20, the increment determination 41 being carried out during the actuating movement 2 is running. A continuous measurement by the sensor arrangement 22 is thereby generated. Alternatively or additionally, the increment determination 41 can be carried out after the moving element 14 has come to a standstill.

In a third step, sensor signals are generated 42 from the counting process 38 and the increment determination 41 , which are transmitted to the evaluation device 24 . The increment sensor unit 28 and the counting sensor unit 26 generate a respective increment sensor signal and a respective counting sensor signal during the positioning movement 2 , which signals are transmitted to the evaluation device 24 .

In a fourth step, the sensor signals are evaluated 44, whereby the absolute position value A is determined. The determination of the absolute position value A can be carried out by a microprocessor in connection with a memory.

Claims (14)

Fluidic actuating device (10), in particular a pneumatic drive cylinder, for providing an actuating movement (2), with a housing (12) on which a moving element (14) is arranged, the moving element (14) moving along an actuating axis (1) relative to the housing (12) can be positioned, a magnet unit (16) providing a magnetic field (15), which is arranged on the moving member (14), the magnetic field (15) having characteristic magnetic field points (20) spaced apart from one another along the adjustment axis (1), one The sensor arrangement (22) arranged on the housing (12) for detecting the magnetic field (15), the sensor arrangement (22) having a counting sensor unit (26) which is used to determine a counting value (Z) by a counting process (38) of the characteristic magnetic field points ( 20) is formed during the positioning movement (2), the counting sensor unit (26) forming a domain wall generator (29) together with the magnet unit (16). Fluidic adjusting device (10) after claim 1 , characterized in that the sensor arrangement (22) has an increment sensor unit (28) by means of which an increment (I) between a characteristic magnetic field point (20) and the increment sensor unit (28) can be determined in order to determine the position of the moving element (14). Fluidic adjusting device (10) after claim 2 , the counting process (38) with the domain wall generator (29) being executable when the evaluation device (24) is electrically voltage-free. Fluidic control device (10) according to one of the preceding claims, characterized in that the counting sensor unit (26) has a giant magnetoresistance layer stack (45) which, together with the magnet unit (16), forms the domain wall generator. Fluidic actuating device (10) according to one of the preceding claims, characterized in that the magnet unit (16) is designed as a magnetic strip which is arranged on a longitudinal section (32) of the moving element (14) aligned along the actuating axis (1), the Counting sensor unit (26) is assigned a fixed counting reference point (30) on the magnet unit (16). Fluidic adjusting device (10) after claim 5 , characterized in that the housing (12) is a fluid cylinder housing (13), the moving member (14) is a fluid piston (19) and/or the longitudinal section (32) is a piston rod (37). Fluidic control device (10) according to one of the preceding claims, characterized in that a distance (D) between adjacent characteristic magnetic field points (20) is identical in each case and preferably results from a periodic magnetic field profile along the control axis (1). Fluidic adjusting device (10) according to one of the preceding claims, characterized in that the counting sensor unit (26) and the incremental sensor unit (28) are adjacent in the direction of the adjusting axis (1). Fluidic control device (10) according to one of the preceding claims, characterized in that the sensor arrangement (22) with the counting sensor unit (26) and the incremental sensor unit (28) is mounted on a printed circuit board, with at least the sensor arrangement (22) being stationary on a housing inner surface ( 34) immediately opposite a mover outer surface (36) on which the magnet unit (16) is mounted. System (100) with a fluidic actuating device (10) according to one of the preceding claims, wherein the sensor arrangement (22) is connected to an evaluation device (24), the evaluation device (24) for determining a position of the moving element (14) using sensor signals the sensor arrangement (22) is formed. Method for determining a position of a moving member (14) assumed by an adjusting movement (2) of a fluidic adjusting device (10) with respect to an on the moving member arranged housing (12) by means of a sensor arrangement (22), in particular according to one of the preceding claims, which is connected to an evaluation device (24), characterized by a counting process (38) of characteristic magnetic field points (20) of a magnetic field (15), the counting process (38) starting from a count reference point (30) during the positioning movement (2), an incremental determination (41) of the position of the moving member (14) between two adjacent characteristic magnetic field points (20) during the positioning movement (2), a generation (42) of sensor signals from the counting process (38) and the increment determination (41), an evaluation (44) of the sensor signals so that, starting from the counting reference point (30), an absolute position value (A) of the moving element (14) with respect to the housing (12) is obtained. procedure after claim 11 , characterized in that the evaluation (44) is multiplied by a counting value (Z) resulting from the counting process (38) by a distance (D) between adjacent characteristic magnetic field points (20), and a from the increment determination (41) resulting from the last counted characteristic magnetic field point (20) starting increment (I) is added to it, so that starting from the counting reference point (30) the absolute position value (A) of the moving element (14) with respect to the housing (12) is obtained. procedure after claim 11 or 12 , characterized in that the counting process (38) takes place during an actuating movement (2) of the moving member (14) independently of an electrical voltage at the evaluation device (24). Procedure according to one of Claims 11 until 13 , characterized in that the absolute position value (A) is compared with a nominal position value by a main controller (49), which contains in particular the evaluation device (24), with a preferably fluidic driver device (40 ), which is in particular a valve device (25), controlled by the main controller (49) in such a way that the moving member (14) performs an actuating movement (2) and the absolute position value (A) is corrected.

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