System and method for terminal position buffering

Abstract

The invention relates to a system and a method for end-position buffering, in particular to a system (100) comprising a pneumatic actuator (2) with an actuator part (3) and a compressed air supply device (4), wherein the compressed air supply device is configured to load the pneumatic actuator (2) with compressed air to place the actuator part (3) in an actuator part movement (60) towards an end position (61) of the pneumatic actuator (2), wherein the compressed air supply device (4) is further configured to provide end-position buffering for the actuator part movement (60) and, in the end-position buffering, adjust the conductance (C) of an outlet valve (33) according to a conductance characteristic curve (62) related to a driving force (FA) acting on the actuator part, via which the compressed air supply device (4) discharges compressed air from a pressure chamber (9) of the pneumatic actuator (2) that acts in opposition to the actuator part movement.

Description

Technical Field

[0001] The present invention relates to a system comprising a pneumatic actuator having an actuator component. Furthermore, the system comprises a compressed air supply device configured to apply compressed air to the pneumatic actuator in order to cause the actuator component to move toward an end position of the pneumatic actuator. The compressed air supply device is configured to provide end-position damping for the actuator component movement. Background Art

[0002] End position buffering is used to reduce the speed at which the actuator component moves into the end position. The movement of the actuator component into the end position can also be called end position travel. End position buffering should be used to prevent the actuator component from traveling into the end position at too high a speed. In particular, it should be prevented that the actuator component hits the end position stop that defines the end position without braking. The movement of the actuator component into the end position that is not braked or is too little braked can cause shaking in the device and can interfere with or damage the process implemented using the device. In addition, the movement of the actuator component that is not braked or is too little braked can cause higher wear of the pneumatic actuator and, in extreme cases, can cause damage to the pneumatic actuator or other components if necessary.

[0003] In order to have an optimal effect, the end position damping must be adapted to the respective application, in particular to the pneumatic actuator and / or the drive object to be driven by means of the actuator component.

[0004] Conventionally, end position damping is provided by an end position damping mechanism. The properties of such end position damping are mechanically determined and cannot be adapted or can be adapted only to a limited extent. Summary of the Invention

[0005] The object of the present invention is to provide an end position cushioning which can be used flexibly.

[0006] This object is achieved by the system described below. The compressed air supply device includes an outlet valve, via which the compressed air supply device discharges compressed air from a pressure chamber of the pneumatic actuator that counteracts the movement of the actuator part. The compressed air supply device is designed to adjust the conductance of the outlet valve during end position cushioning as a function of a conductance characteristic curve that is dependent on the drive force acting on the actuator part.

[0007] The compressed air supply device thus provides end-position cushioning via the outlet valve and adjusts the outlet valve's conductance according to a conductance characteristic curve that is correlated with the driving force. The driving force can be specifically influenced via the outlet valve's conductance. This creates a feedback loop in which the conductance determines the driving force, and the conductance is adjusted based on the driving force. In particular, the compressed air supply device continuously calculates the driving force (e.g., based on a measured pressure value) and continuously adjusts the conductance based on this driving force. In the case of a low conductance, compressed air is discharged more slowly from the pressure chamber, resulting in a higher pressure acting against the actuator component movement and, as a result, a lower generated driving force, particularly a negative driving force. The drive component is braked more strongly. In the case of a high conductance, compressed air is discharged more quickly from the pressure chamber, resulting in a lower pressure acting against the actuator component movement and a higher generated driving force. The drive component is braked less strongly or even accelerated. The relationship between the driving force and the conductance to be adjusted is described by a conductance characteristic curve. This conductance characteristic curve is stored, for example, electronically in the compressed air supply device, particularly in a control unit.

[0008] The properties of the end-position damping are therefore determined via the conductance characteristic curve and not (as in the prior art) by structural means. The conductance characteristic curve allows the end-position damping to be adapted to different applications and thus to be used flexibly.

[0009] The conductance is proportional to the size of the outlet opening provided by the outlet valve, through which the compressed air is discharged from the pressure chamber to a compressed air outlet, such as the atmosphere. Therefore, adjusting the conductance (via the compressed air supply device) corresponds to adjusting the outlet opening. In supercritical flow, the conductance is the ratio of the compressed air volume flow through the outlet opening to the inlet pressure of the outlet valve. The inlet pressure is the compressed air pressure on the side of the outlet opening facing the pressure chamber.

[0010] According to a preferred embodiment, the relationship between the conductance to be adjusted and the driving force, as described by the conductance characteristic curve, is such that the conductance to be adjusted increases progressively as the driving force decreases. The conductance preferably increases quadratically or at least quadratically (as the driving force decreases). Thus, the rapidly opening outlet opening of the outlet valve reacts to the decreasing driving force of the actuator component. This prevents excessive braking of the actuator component.

[0011] The present invention further relates to a method for end-position damping of an actuator part of a pneumatic actuator, which performs a movement of the actuator part toward an end position. The method comprises the steps of discharging compressed air from a pressure chamber of the pneumatic actuator, which pressure chamber counteracts the movement of the actuator part, via an outlet valve, and regulating the conductance of the outlet valve during the discharge of the compressed air as a function of a conductance characteristic curve that is dependent on the driving force acting on the actuator part.

[0012] According to a preferred development, the method is carried out using the system or is designed based on the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In the following, exemplary details and exemplary embodiments are explained with reference to the accompanying drawings.

[0014] Figure 1 A schematic diagram showing a system with a compressed air supply, a hose assembly, and a pneumatic actuator is shown.

[0015] Figure 2 shows a schematic diagram of a valve device,

[0016] Figure 3 shows a schematic diagram of a pneumatic actuator,

[0017] Figure 4 A graph showing the conductance characteristic curve, and

[0018] Figure 5 A flow chart of the method is shown. DETAILED DESCRIPTION

[0019] Figure 1 The system 100 is shown, which comprises a pneumatic actuator 2 that can be acted upon with compressed air and a compressed air supply device 4. Furthermore, the system 100 comprises, by way of example, a hose assembly 28 that connects the compressed air supply device 4 to the pneumatic actuator 2.

[0020] The pneumatic actuator 2 has an actuator part 3. The compressed air supply device 4 is designed to supply compressed air to the actuator 2 via a hose assembly 28 in order to bring the actuator part 3 into a target position, in particular an end position.

[0021] The system 100 is expediently used in industrial automation, for example, to position a driven object such as a tool, a workpiece, and / or a machine part via an actuator component 3 .

[0022] The compressed air supply device 4 includes a valve assembly 14, through which compressed air for positioning the actuator 2 is provided. Exemplarily, the valve assembly 14 is implemented as a valve island (Ventilinsel, sometimes called a valve group). Alternatively, the valve assembly 14 can also be implemented as a single valve or other valve device.

[0023] There are two pressure outlets 23, 24 at the valve assembly 14 for providing compressed air. Each of the two pressure outlets 23, 24 is pneumatically connected to a corresponding pressure chamber 8, 9 of the pneumatic actuator 2. The valve assembly 14 can supply and exhaust air to the two pressure outlets 23, 24 independently of each other. The valve assembly 14 includes a first discharge valve 32 (at Figure 2 ) to vent the first pressure chamber 8. The first outlet valve 32 is connected between the first pressure outlet 23 and the compressed air reduction part, such as the atmosphere. The valve assembly 14 also includes a second outlet valve 33 (in Figure 2 ) to exhaust the second pressure chamber 9. The second outlet valve 33 is connected between the second pressure outlet 24 and the compressed air reduction part, such as the atmosphere.

[0024] The valve assembly 14 is provided with a pressure sensor assembly 29 (at Figure 2 ), with the aid of the pressure sensors, the pressure at the pressure outlets 23, 24 and / or the pressure in the exhaust port 26 and / or the supply port 27 can be measured. These pressure sensors are expediently arranged at the valve assembly 14, in particular at the valve terminal.

[0025] Exemplarily, the valve assembly 14 includes a plurality of modules, such as a valve module 17 and / or an I / O module 18. The valve assembly 14 also includes a control unit 19, which is preferably also implemented as a module. The valve assembly 14 expediently has a support body 20, in particular a support plate, on which the control unit 19, the valve module 17, and / or the I / O module 18 are arranged.

[0026] The valve assembly 14 is exemplarily implemented as a serial module assembly and can also be referred to as a valve island. The modules are preferably implemented as sheet-shaped serial modules. The valve module 17 is preferably implemented as a valve sheet. The serial modules are preferably connected in series with each other, especially along the longitudinal axis of the valve assembly 14.

[0027] The compressed air supply device 4 exemplarily further comprises a higher-level controller 15 and / or optionally a cloud server 16 and / or a user device 49 .

[0028] The valve assembly 14 is suitably communicatively connected to a superior controller 15 and / or a cloud server 16. Preferably, the valve assembly 14 is connected to the superior controller 15 via a bus 25, in particular a local bus such as a field bus, and / or optionally to the cloud server 16 via a wide area network 22, such as the Internet.

[0029] Valve assembly 14 is communicatively connected to position sensor device 10 of actuator 2, in particular via I / O module 18. Exemplarily, valve assembly 14 is communicatively connected to position sensor device 10 via one or more communication lines 91, 92. The position value acquired by position sensor device 10 is preferably provided to control unit 19, superordinate controller 15, and / or cloud server 16. Furthermore, the pressure values ​​of pressure sensors 43, 44, 45, and 46 are also preferably provided to control unit 19, superordinate controller 15, and / or cloud server 16.

[0030] The pneumatic actuator 2 is exemplarily designed as a drive, in particular as a drive cylinder. The pneumatic actuator 2 exemplarily comprises an actuator body 7, an actuator component 3, and two pressure chambers 8, 9. The two pressure chambers 8, 9 can advantageously be pressurized independently of one another with compressed air. The pneumatic actuator 2 is particularly designed as a double-acting actuator.

[0031] The actuator body 7 is preferably designed as a cylinder and has an internal volume. The actuator part 3 comprises, for example, a piston 5 and / or a piston rod 6. The piston 5 is arranged in the actuator body 7 and divides the internal volume of the actuator body 7 into two pressure chambers 8, 9.

[0032] The pneumatic actuator 2 expediently includes a position sensor device 10. The position sensor device 10 is used, in particular, to detect the position of the actuator component 3. The position sensor device 10 provides a position value that describes the position of the actuator component 3. The position sensor device 10 is preferably designed as an analog position transmitter. The position sensor device 10 is arranged, for example, outside the actuator body 7. The position sensor device 10 includes, for example, two position sensor units 11, 12, which are arranged distributed along the movement path of the actuator component 3. For example, the position sensor units 11, 12 together cover the entire movement path of the actuator component 3.

[0033] Each position sensor unit 11 , 12 may include, for example, one or more sensor elements (not shown in the figures), in particular magnetic sensor elements, such as Hall sensor elements. A magnet, whose magnetic field can be detected by the magnetic sensor elements, is advantageously arranged on the actuator component 3 .

[0034] The position sensor means 10 is expediently designed to detect the position of the actuator part 3 over the entire movement path of the actuator part 3 .

[0035] Expediently, no pressure sensor is present on the pneumatic actuator 2 , in particular no pressure sensor for measuring the pressure in one of the pressure chambers 8 , 9 .

[0036] The system 100 advantageously includes a hose assembly 28, via which the compressed air supply device 4, in particular the valve assembly 14, is pneumatically connected to the pneumatic actuator 2. A first hose 51 pneumatically connects the first pressure outlet 23 to the first pressure chamber 8, and a second hose 52 pneumatically connects the second pressure outlet 24 to the second pressure chamber 9.

[0037] The superordinate controller 15 is exemplarily designed as a programmable logic controller (SPS) and is communicatively connected to the valve assembly 14, in particular to the control unit 19. The superordinate controller 15 is also expediently connected to a cloud server 16, in particular via a wide area network 22, preferably via the Internet. The superordinate controller 15 is expediently designed to provide a target value signal that specifies a target position, for example, an end position to which the actuator component 3 is to be positioned.

[0038] The user device 49 is exemplarily a mobile device, such as a smartphone, tablet computer, and / or laptop computer. Alternatively, the user device 49 may be a desktop computer, such as a PC. The user device 49 is preferably communicatively connected to the control unit 19, the cloud server 16, and / or the higher-level controller 15, in particular via a wide area network 22, such as the Internet. A user interface, such as provided on the cloud server 16, the controller 15, and / or the control unit 19, can be conveniently accessed via the user device 49. The user interface is preferably a website interface. The user interface is particularly used for selecting, activating, and / or loading an application that provides terminal location buffering onto the control unit 19. Furthermore, the user device 49 is preferably configured to operate and / or display the application that provides terminal location buffering.

[0039] The cloud server 16 is preferably located remotely from the valve assembly 14 and / or the pneumatic actuator 2 , in particular at a different geographical location. The cloud server 16 is preferably configured to provide an application that provides for end-position buffering. The application can be loaded from the cloud server 16 onto the superordinate controller 15 and / or the control unit 19 , preferably in response to user input via the user device 49 .

[0040] Figure 2 An exemplary valve device 21 is shown, by means of which each of the two pressure chambers 8 , 9 can be supplied with air and exhausted. The valve device 21 is part of the compressed air supply device 4 , in particular the valve assembly 14 , preferably the valve module 17 .

[0041] The valve device 21 has two pressure outlets 23 and 24. Furthermore, the valve device 21 has an exhaust port 26 connected to an exhaust line and a supply port 27 connected to an air supply line. Preferably, supply pressure is present at the supply port 27. The exhaust port 26 is connected to a compressed air step-down, in particular, the atmosphere. Atmospheric pressure is preferably present at the exhaust port 26.

[0042] The valve device 21 includes four valve units, specifically a first inlet valve 31, a first outlet valve 32, a second outlet valve 33, and a second inlet valve 34. Each of the valve units includes a corresponding valve element 48. Each of the four valve units is designed as a 2 / 2-way valve. Exemplarily, each valve unit is configured as a proportional valve; that is, each valve unit has a valve element 48 that can be positioned in an open position, a closed position, and any intermediate position therebetween. Preferably, the valve units are pilot-controlled valves, each having two pilot valves 41, 42, via which the valve elements 48 can be actuated. Exemplarily, the pilot valves 41, 42 are configured as piezoelectric valves. The position of the respective valve element 48 allows the size of the inlet or outlet opening of the respective valve unit to be adjusted appropriately.

[0043] The valve device 21 is preferably implemented as a full bridge consisting of the four valve units. The first inlet valve 31 is connected between the air supply port 27 and the first pressure outlet 23. The size of the first inlet opening, through which compressed air is supplied from the air supply port 27 to the first pressure outlet 23, can be adjusted via the valve element 48 of the first inlet valve 31. The first outlet valve 32 is connected between the first pressure outlet 23 and the exhaust port 26. The size of the first outlet opening, through which compressed air is discharged from the first pressure outlet 23 to the exhaust port 26, can be adjusted via the valve element 48 of the first outlet valve 32. The second outlet valve 33 is connected between the exhaust port 26 and the second pressure outlet 24. The size of the second outlet opening, through which compressed air is discharged from the second pressure outlet 24 to the exhaust port 26, can be adjusted via the valve element 48 of the second outlet valve 33. The second inlet valve 34 is connected between the second pressure outlet 24 and the air supply port 27. The size of the second inlet opening, through which compressed air is supplied from the air supply port 27 to the second pressure outlet 24, can be adjusted via the valve element 48 of the second inlet valve 34.

[0044] The first pressure outlet 23 can be optionally connected to an exhaust line via a first outlet valve 32 or to an air supply line via a first input valve 31 , and the second pressure outlet 24 can be optionally connected to an exhaust line via a second outlet valve 33 or to an air supply line via a second input valve 34 .

[0045] The valve assembly 14 expediently includes a pressure sensor assembly 29 with one or more pressure sensors for detecting the pressure of the valve assembly 14 , in particular the valve device 21 .

[0046] Exemplarily, the pressure sensor assembly 29 includes a first pressure outlet pressure sensor 45 for acquiring the pressure provided at the first pressure outlet 23 and / or a second pressure outlet pressure sensor 46 for acquiring the pressure provided at the second pressure outlet 24. Suitably, the pressure sensor assembly 29 further includes an intake pressure sensor 44 for acquiring the pressure provided at the supply connection 27 and / or an exhaust pressure sensor 43 for acquiring the pressure provided at the exhaust connection 26.

[0047] The valve assembly 14, in particular the valve means 21, expediently comprises a travel sensor 47 for detecting the position of the valve element 48. The compressed air supply device 4 is designed in particular to determine the size of the inlet opening and the outlet opening by means of the travel sensor 47.

[0048] Figure 3 The pneumatic actuator 2 is shown in a state in which the actuator part 3 carries out an actuator part movement 60 towards an end position 61 of the pneumatic actuator 2 .

[0049] The compressed air supply device 4 is designed to apply compressed air to the pneumatic actuator 2 so that the actuator part 3 is brought into an actuator part movement 60 toward an end position 61 of the pneumatic actuator 2. For example, the higher-level controller 15 outputs a target value signal to the control unit 19, which specifies an end position 64 for the actuator part 3 as a target position. In response to the target value signal, the control unit 19 actuates the valve element 21 so that the valve element 21 vents the first pressure chamber 8 and exhausts the second pressure chamber 9, thereby bringing the actuator part 3 into the actuator part movement 60 toward the end position 61. For example, the control unit 19 of the valve element 21 predetermines a plurality of conductances, as a function of which the position of the valve element 48 is adjusted so that the first pressure chamber 8 is vented and the second pressure chamber 9 is exhausted.

[0050] The end position 61 is also referred to as the first end position 61 . The actuator component movement 60 occurs in a first direction of movement. Exemplarily, the actuator component 3 , in particular the piston rod 6 , moves out of the actuator body 7 during the actuator component movement 60 . The end position 61 is the first end point of the (exemplarily linear) movement path of the actuator component 3 . In the first end position 61 , the actuator 3 abuts against an end position stop, which prevents further movement of the actuator 3 in the first direction of movement. The end position stop is, for example, an end face of the interior volume of the actuator body 7 .

[0051] The actuator component movement 60 comprises, by way of example, a movement phase 64 and a damping phase 65 following the movement phase 64 .

[0052] The movement phase 64 extends exemplarily over at least 50%, in particular at least 75%, of the movement path. In the movement phase 64, the compressed air supply device 4 expediently does not implement end position buffering of the actuator component 3. The movement phase can be implemented, for example, as a throttled travel. The movement path can also be referred to as a stroke. In the movement phase 64, the compressed air supply device 4 supplies air to the first pressure chamber 8 via the first inlet valve 31 and exhausts the second pressure chamber 9 via the second outlet valve 33. Exemplarily, the compressed air supply device 4 obtains the movement phase driving force FB (at Figure 4 (shown in FIG), this motion phase driving force is required to overcome forces acting in opposition to the drive component movement 60, such as friction and / or gravity. Preferably, the compressed air supply device 4 obtains the conductance (also referred to as motion phase conductance CB) of the second outlet valve 33 required for the motion phase driving force FB. For example, the compressed air supply device 4 obtains the motion phase conductance CB based on the position of the valve member 48 of the second outlet valve, which is obtained using the travel sensor 47.

[0053] The movement phase 64 is followed by a damping phase 65. The damping phase 65 expediently follows directly after the movement phase 64. In the damping phase 65, the compressed air supply device brakes the actuator part 3 so that the actuator part 3 moves into the end position 61 at a reduced speed.

[0054] The compressed air supply device 4 is designed to provide end-position damping for the actuator part movement 60 in order to brake the actuator part 3 in a damping phase 65. During end-position damping, the compressed air supply device 4 is designed to adjust the conductance C of the second outlet valve 33 as a function of a conductance characteristic curve 62 that is dependent on the drive force FA. The drive force FA acts on the actuator part 3. The compressed air supply device 4 discharges compressed air from the second pressure chamber 9 via the outlet valve 33. The second pressure chamber 9 counteracts the actuator part movement 60.

[0055] The compressed air supply device 4 is particularly configured to provide a control of the driving force FA by adjusting the conductance C. In particular, the compressed air supply device 4 provides a feedback loop. The driving force FA is varied by the adjusted conductance C. The conductance C is in turn adjusted based on the driving force FA. Advantageously, the compressed air supply device 4 is configured to continuously calculate the driving force FA during the buffer phase and to continuously adjust the conductance C according to the conductance characteristic curve 62 based on the determined driving force FA. In particular, the compressed air supply device 4 is configured to provide a continuous control of the driving force FA during the buffer phase based on the conductance characteristic curve 62. Advantageously, the control of the driving force FA is not based on the position of the actuator component 3. The control of the driving force FA is particularly nonlinear.

[0056] Preferably, the compressed air supply device 4 is designed to block the first pressure chamber 8 in the buffer phase 65 , ie, close the first inlet valve 31 and the first outlet valve 32 , or to vent the first pressure chamber 8 , ie, open the first outlet valve 32 and suitably close the first inlet valve 31 .

[0057] The following should be described in more detail Figure 4 Conductivity characteristic curve 62 is shown in FIG. Actuating force FA is plotted on the x-axis, and conductance C of second outlet valve 33 to be adjusted is plotted on the y-axis.

[0058] Conductivity characteristic curve 62 describes the relationship between the conductance C to be adjusted and the obtained driving force FA. Exemplarily, the relationship between the conductance C to be adjusted and the driving force FA is such that the conductance C to be adjusted increases progressively as the driving force FA decreases. In particular, the relationship between the conductance C to be adjusted and the driving force FA is such that the conductance C to be adjusted increases at least quadratically as the driving force FA decreases. Therefore, conductance characteristic curve 62 preferably includes a polynomial with an order greater than or equal to second. According to a preferred design, the relationship between the conductance C to be adjusted and the driving force FA is quadratic. As the driving force FA decreases, the conductance C to be adjusted increases quadratically.

[0059] Conductivity characteristic curve 62 exemplarily includes a progressive section 66. Starting from a positive driving force threshold value FS, progressive section 66 extends into the region of negative driving force FA, i.e., from the first quadrant of the illustrated diagram into the second quadrant. The conductance C of progressive section 66 increases progressively, in particular at least quadratically, preferably quadratically, as the driving force FA decreases. The conductance C of progressive section 66 is advantageously always positive.

[0060] Conductance characteristic curve 62 also exemplarily includes a constant section 67. Constant section 67 extends from the positive driving force threshold FS in the positive direction of driving force FA. Constant section 67 is located only in the first quadrant. The conductance C of constant section 67 is constant. Preferably, the conductance C of constant section 67 is equal to the reduced conductance CR.

[0061] Exemplarily, the transition from the progressive section 66 to the constant section 67 is continuous.

[0062] The compressed air supply device 4 is suitably configured to compare the driving force FA with a driving force threshold value FS. In response to the driving force FA being less than the driving force threshold value FS, the compressed air supply device 4 adjusts the conductance C of the second outlet valve 33 according to the conductance characteristic curve 62, in particular according to the progressive section 66. The more the driving force FA decreases, the more the outlet opening of the outlet valve 33 opens, thereby preventing or reducing a further decrease in the driving force FA.

[0063] In response to the driving force FA being greater than the driving force threshold FS, the compressed air supply device 4 sets the conductance C of the second outlet valve 33 to a reduced conductance CR (e.g., based on the movement phase conductance CB) and / or maintains the conductance C at the reduced conductance CR (if the conductance C is already set to the reduced conductance CR). In particular, the compressed air supply device 4 is configured to reduce the conductance C by a reduction factor to reduce the conductance C to the reduced conductance CR. Exemplarily, the compressed air supply device 4 is configured to adjust the conductance C to the reduced conductance CR according to the constant section 67 in response to the driving force FA being greater than the driving force threshold FS.

[0064] Therefore, if the driving force FA is greater than the driving force threshold FS, the conductance C is reduced to a reduced conductance CR. This reduction in conductance C typically occurs during the transition from the movement phase 64 to the buffer phase 65. In the movement phase 64, the conductance C is equal to the movement phase conductance C. When entering the buffer phase, the compressed air supply device 4 reduces the conductance C of the second outlet valve 33 from the movement phase conductance CB to the reduced conductance CR (as long as the driving force FA is greater than the driving force threshold FS). The reduction in conductance C reduces the outlet opening of the outlet valve 33, thereby reducing the driving force FA. In particular, the reduction in the outlet opening generates a braking force that counteracts the movement 60 of the actuator component. According to one possible design, the outlet opening can be completely closed.

[0065] The stored conductivity characteristic curve results in a force control of the acting drive force FA, resulting in a braking of the actuator part 3. In addition, it is achieved that reverse oscillations of the actuator part 3 are avoided.

[0066] The compressed air supply device 4 is expediently designed to provide corresponding end-position damping for the second actuator part movement (opposite to the first actuator part movement 60) into the second end position 68. In particular, the compressed air supply device 4 is designed to adjust the conductance of the first outlet valve 32 according to the conductance characteristic curve 62 during the end-position damping of the second actuator part movement.

[0067] The following describes how to activate end position cushioning.

[0068] According to a preferred embodiment, the compressed air supply device 4 is configured to provide end-position cushioning in response to a predetermined activation criterion being met. The predetermined activation criterion is, for example, a predetermined position 63, which the actuator component 3 passes through during the actuator component movement 60. In response to the actuator component 3 reaching the predetermined position 63, the compressed air supply device 4 initiates end-position cushioning. The predetermined position 63 thus marks the transition from the movement phase 64 to the cushioning phase 65. The position of the actuator component 3 is measured, for example, by means of the position sensor device 10 and / or calculated based on the detected compressed air pressure.

[0069] The compressed air supply device 4 can also be configured to use the amount of compressed air supplied as an activation criterion for end-position cushioning. For example, the compressed air supply device 4 is configured to trigger the end-position cushioning in response to the amount of compressed air supplied to the first pressure chamber 8 exceeding a predetermined threshold value.

[0070] The end-position cushioning can be suitably adapted to the system 100, in particular the pneumatic actuator 2. The compressed air supply device 4 is preferably designed to adapt the end-position cushioning based on at least one system parameter. The at least one system parameter includes, for example, the actuator geometry of the actuator 2 and / or the hose geometry of the hose assembly 28. For example, the at least one system parameter includes the cylinder diameter and / or cylinder length of the pneumatic actuator 2. Furthermore, the at least one system parameter may include a mass, in particular a mass moving during the actuator component movement 60. Furthermore, the at least one system parameter may include the hose length of the hose assembly 28. The compressed air supply device 4 is suitably designed to adapt the conductivity characteristic curve 62, the reduction factor, and / or the activation criterion based on the system parameters. In particular, the compressed air supply device 4 is designed to adapt the parameters of the conductivity characteristic curve 62, in particular the progressive section 66, based on the system parameters.

[0071] System 100 also advantageously includes a user interface through which user parameters for adapting the terminal position buffer can be input. The user interface is provided, for example, by user device 49. User parameters are, for example, tuning parameters. User parameters describe, for example, the conductivity characteristic curve 62, a reduction factor, and / or an activation criterion. User parameters can also be the aforementioned system parameters.

[0072] Expediently, the end position buffering is provided by means of a program, in particular an application, executed on the control unit 19 .

[0073] In particular, the calculation of the driving force FA and / or the determination of the conductance C to be adjusted is carried out by the microcontroller of the control unit 19 based on the conductance characteristic curve 62 . The conductance characteristic curve 62 is expediently stored in the control unit 19 , in particular in the microcontroller of the control unit 19 .

[0074] Exemplarily, the compressed air providing device 4 is configured to calculate the driving force FA based on a pressure value of the compressed air obtained, for example, by the pressure sensor assembly 29 .

[0075] In particular, the compressed air supply device 4 is configured to calculate the driving force FA as the difference between a first aerodynamic force FAD acting on the actuator component 3 in a first direction of motion (the direction of motion of the actuator component motion 60) and a second aerodynamic force FLD acting on the actuator component 3 in a second direction of motion (opposite to the first direction of motion). In particular, the compressed air supply device 4 is configured to calculate the first aerodynamic force FAD and / or the second aerodynamic force FLD based on a pressure value of the compressed air.

[0076] For example, the compressed air supply device 4 is configured to calculate the driving force FA in the following manner:

[0077] FA = FAD – FLDFAD is the first aerodynamic force acting in the first direction of motion, which is provided by applying compressed air to the first pressure chamber 8 . For example, FAD is calculated as the product of the pressure p8 in the first pressure chamber 8 and the first active surface A1 of the actuator component 3 on which the pressure p8 acts. Therefore, FAD is calculated as FAD = p8 * A1. The pressure p8 is preferably calculated based on the pressure value of the first pressure outlet 23 acquired using the pressure sensor assembly 29 . According to an alternative design in which a pressure sensor is present on the actuator 2 , the pressure p8 can also be measured directly on the actuator 2 as a pressure value.

[0078] FLD is the second pneumatic force acting in the second direction of motion, which is provided by applying compressed air to the second pressure chamber 9 and / or by the ambient pressure acting on the actuator component 3, in particular, the piston rod 6. For example, FLD comprises the product of the pressure p9 in the second pressure chamber 9 and the second effective surface A2 of the actuator component 3 (on which the pressure p8 acts). Furthermore, FLD exemplarily comprises the product of the ambient pressure pamb, in particular atmospheric pressure, and the third effective surface A3 of the actuator component 3 (on which the ambient pressure pamb acts). Exemplarily, the third effective surface A3 is determined as the difference between the first effective surface A1 and the second effective surface A2. Therefore, FLD is calculated as FLD = p9 * A2 + Pamb * (A1 - A2). Pressure p9 is preferably calculated based on the pressure value of the second pressure outlet 24 acquired using the pressure sensor assembly 29. According to an alternative design in which a pressure sensor is present on the actuator 2, pressure p9 can also be measured directly on the actuator 2 as a pressure value.

[0079] Pressures p8 and p9 in pressure chambers 8 and 9 are calculated, for example, based on the pressure values ​​of pressure outlets 23 and 24 acquired using pressure sensor assembly 29. The pressure values ​​acquired using pressure sensor assembly 29 may also be referred to as measured pressures, and the pressures p8 and p9 calculated based on the measured pressures may also be referred to as calculated pressures. Calculated pressures are, in particular, estimated pressures.

[0080] The compressed air supply device 4 is therefore preferably designed to measure a measured pressure of the compressed air supply device 4 using the pressure sensor assembly 29 and to calculate a calculated pressure based on the measured pressure, which represents the pressure prevailing in the pressure chambers 8, 9 of the pneumatic actuator 2. The compressed air supply device 4 is also designed to calculate the drive force FA based on the calculated pressure.

[0081] The compressed air supply device 4 is preferably configured to use a hose model of the hose assembly 28 to calculate the calculated pressure. The hose model describes the influence of the hose on the pressure. The hose model describes the dependence of the respective pressures in the pressure chambers 8, 9 on the respective pressures at the pressure outlets 23, 24.

[0082] refer to Figure 5 , a method for end position cushioning of the actuator part 3 will be described below.

[0083] The method comprises a first step S1 in which the actuator part 3 is brought into an actuator part movement 60 towards a first end position 61. In step S1, the first pressure chamber 8 is ventilated and the second pressure chamber 9 is exhausted.

[0084] The method continues with step S2 , in which it is checked whether an activation criterion is met. For example, in step S2 , it is checked whether the actuator part 3 has reached the predetermined position 63 .

[0085] In response to the activation criterion being met, the method continues with step S3. In step S3, the movement phase 64 ends and the buffer phase 65 begins. In step S3, the end position buffering of the actuator part 3 is activated. Furthermore, the air supply to the first pressure chamber 8 is expediently terminated in step S3. During the buffer phase, compressed air is (continuously) discharged from the pressure chamber 9, which counteracts the actuator part movement 60, via the outlet valve 33.

[0086] The method continues with step S4 , in which the driving force FA is calculated and a check is performed to determine whether the driving force FA is greater than a driving force threshold value FS.

[0087] In response to the driving force FA being greater than the driving force threshold FS, step S5 is implemented, in which the conductance C of the discharge valve 33 is reduced to the reduced conductance CR. If the conductance C is already equal to the reduced conductance CR, the conductance C is maintained at the reduced conductance CR. The method then returns to step S4.

[0088] In response to the driving force FA not being greater than the driving force threshold FS, the method continues with step S6. In step S6, the conductance of the outlet valve 33 is adjusted in dependence on the driving force FA according to the conductance characteristic curve 62, in particular according to the progressive section 66. The method then returns to step S4.

Claims

1. A system (100) for end position cushioning, comprising a pneumatic actuator (2) with an actuator part (3) and a compressed air supply device (4), wherein the compressed air supply device is configured to load the pneumatic actuator (2) with compressed air in order to bring the actuator part (3) into an actuator part movement (60) towards an end position (61) of the pneumatic actuator (2), wherein: The compressed air supply device (4) is further configured to provide end-position buffering for the movement of the actuator part (60), and in the end-position buffering, the conductance (C) of the outlet valve (33) is adjusted according to a conductance characteristic curve (62) depending on the driving force (FA) acting on the actuator part, wherein the compressed air supply device (4) discharges compressed air from a pressure chamber (9) of the pneumatic actuator (2) that acts in opposition to the movement of the actuator part via the outlet valve (33), wherein the conductance characteristic curve describes the relationship between the driving force and the conductance to be adjusted.

2. The system (100) according to claim 1, characterized in that The compressed air supply device (4) is configured to provide control of the driving force (FA) by adjusting the conductance (C).

3. The system (100) according to claim 1 or 2, characterized in that In this relationship, the conductance (C) to be adjusted increases progressively as the driving force (FA) decreases.

4. The system (100) according to claim 1 or 2, characterized in that In this relationship, the conductance (C) to be adjusted increases at least quadratically when the driving force (FA) decreases.

5. The system (100) according to claim 1 or 2, characterized in that The compressed air providing device (4) is configured to set the conductance (C) to a reduced conductance (CR) and / or maintain it at the reduced conductance (CR) in response to the driving force (FA) being greater than a driving force threshold (FS).

6. The system (100) according to claim 5, characterized in that The compressed air supply device (4) is configured to reduce the conductance (C) by a reduction factor so as to reduce the conductance (C) to the reduced conductance (CR).

7. The system (100) according to claim 1 or 2, characterized in that The compressed air supply device (4) is configured to adjust the conductance (C) according to the conductance characteristic curve (62) in response to the driving force (FA) being less than a driving force threshold (FS).

8. The system (100) according to claim 1 or 2, characterized in that The compressed air supply device (4) is designed to activate the end position cushioning in response to the fulfillment of a predetermined activation criterion.

9. The system (100) according to claim 8, characterized in that The predetermined activation criterion is that the actuator element (3) reaches a predetermined position (63).

10. The system (100) according to claim 1 or 2, characterized in that The compressed air supply device (4) is designed to adapt the end position damping based on system parameters.

11. The system (100) according to claim 10, characterized in that The system parameters are the geometry of the pneumatic actuator (2) and / or the hose geometry of a hose assembly (28) connecting the pneumatic actuator (2) to the compressed air supply device (4).

12. The system (100) according to claim 1 or 2, characterized in that The compressed air supply device (4) is designed to adapt the conductivity characteristic curve (62) based on system parameters.

13. The system (100) according to claim 12, characterized in that The system parameters are the geometry of the pneumatic actuator (2) and / or the hose geometry of a hose assembly (28) connecting the pneumatic actuator (2) to the compressed air supply device (4).

14. The system (100) according to claim 6, characterized in that The compressed air supply device (4) is configured to adapt the reduction factor based on system parameters.

15. The system (100) according to claim 14, characterized in that The system parameters are the geometry of the pneumatic actuator (2) and / or the hose geometry of a hose assembly (28) connecting the pneumatic actuator (2) to the compressed air supply device (4).

16. The system (100) according to claim 8, characterized in that The compressed air supply device (4) is designed to adapt the activation criterion based on system parameters.

17. The system (100) according to claim 16, characterized in that The system parameters are the geometry of the pneumatic actuator (2) and / or the hose geometry of a hose assembly (28) connecting the pneumatic actuator (2) to the compressed air supply device (4).

18. The system (100) according to claim 1 or 2, characterized in that The system further comprises a user interface, via which user parameters can be input for adapting the terminal position buffer.

19. The system (100) according to claim 1 or 2, characterized in that The system further comprises a user interface via which user parameters can be input for adapting the conductivity characteristic curve (62).

20. The system (100) according to claim 6, characterized in that The system further comprises a user interface, via which user parameters can be input for adapting the reduction factor.

21. The system (100) according to claim 8, characterized in that The system further comprises a user interface, via which user parameters can be input for matching the activation criteria.

22. A method for end position damping of an actuator part (3) of a pneumatic actuator (2) for performing an actuator part movement (60) towards an end position (61), the method comprising the following steps: Compressed air is discharged from a pressure chamber (9) of the pneumatic actuator (2) which counteracts the movement (60) of the actuator part via an outlet valve (33), and during the discharge of the compressed air, the conductance of the outlet valve (33) is adjusted as a function of the driving force (FA) acting on the actuator part (3) according to a conductance characteristic curve (62), wherein the conductance characteristic curve describes the relationship between the driving force and the conductance to be adjusted.

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