WO2025147307A1

WO2025147307A1 - Systems and methods associated with pressure profiling

Info

Publication number: WO2025147307A1
Application number: PCT/US2024/050172
Authority: WO
Inventors: Casey M. TIMM
Original assignee: Parker Hannifin Corp
Current assignee: Parker Hannifin Corp
Priority date: 2024-01-03
Filing date: 2024-10-07
Publication date: 2025-07-10
Anticipated expiration: 2026-07-03

Abstract

An example method includes receiving sensor information from pressure sensors indicating pressure levels in chambers of a cylinder actuator; determining various time derivatives for the pressure levels in the chambers; and determining based on the time derivatives one or more of a plurality of points in time comprising: (i) a time at which the valve member is shifted, (ii) a time at which pressure level in a supply line connecting the control valve to the first chamber begins to increase, (iii) a time at which the piston begins to move, (iv) a time at which the piston reaches an end of stroke, or (v) a time at which pressure level in the supply line reaches a steady state.

Description

Systems and Methods Associated with Pressure Profiling

CROSS REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63/617,105, filed on January 3, 2024, and U.S. Provisional Patent Application No. 63/561,348, filed on March 5, 2024, the entire contents of all of which are herein incorporated by reference as if fully set forth in this description.

BACKGROUND

[0002] Control valves are commonly used to control one or more actuators (e.g., piston-cylinder actuators) in a pneumatic system, such as operating machinery in a factory, for example. Each movable member (e.g., a piston) in the system is typically controlled by the movement of a valve member, such as a spool, that moves within a valve body to permit, restrict, and/or control the flow of the working fluid (e.g., air) through different fluid passages in the valve body, thereby controlling the movement of the movable member of the actuator.

[0003] A valve bank is an assembly of such control valve(s), which may include a single control valve to operate a single movable member, or may include a plurality of control valves to operate a plurality of movable members. Typically, the valve bank includes a plurality of control valve sections, in which each control valve section is connected to a base that constitutes a fluid manifold through which operating fluid is communicated. This allows the operating fluid to be supplied from a source into the fluid manifold, and fluid can then be supplied to the individual control valves. [0004] An electronic controller can be configured to control the valve bank. The controller can send command signals to control of the control valve via a suitable valve actuator, such as a solenoid actuator.

[0005] It may be desirable to further configure the controller to detect parameters that indicate a health of the valve bank or the system. It is with respect to these and other considerations that the disclosure made herein is presented.

SUMMARY

[0006] The present disclosure describes implementations that relate to systems and methods associated with pressure profiling.

[0007] In a first example implementation, the present disclosure describes a method. The method includes: determining, by a controller, an initial time when a command signal is provided to one or more actuators of a control valve, wherein the control valve has a valve member disposed therein and movable by one or more actuators, wherein the valve member controls fluid flow to and from a cylinder actuator having a cylinder and a piston movable within the cylinder, wherein the piston divides an internal space of the cylinder into a first chamber and a second chamber, and wherein the control valve includes a first pressure sensor that provides sensor information indicative of pressure level in the first chamber, and a second pressure sensor that provides sensor information indicative of pressure level in the second chamber; receiving sensor information from the first pressure sensor and the second pressure sensor; determining a first derivative and a second derivative of pressure level in the first chamber with respect to time, and a respective first derivative and a respective second derivative of pressure level in the second chamber with respect to time; determining, by the controller based on the first derivative, the respective first derivative, the second derivative, and the respective second derivative, a plurality of points in time comprising: (i) a time at which the valve member is shifted, (ii) a time at which pressure level in a supply line connecting the control valve to the first chamber begins to increase, (iii) a time at which the piston begins to move, (iv) a time at which the piston reaches an end of stroke, and (v) a time at which pressure level in the supply line reaches a steady state; and determining, based on the initial time and the plurality of points in time: (i) actuator response time of the one or more actuators, (ii) response time of the piston, and (iii) a stroke time for the piston. [0008] In a second example implementation, the present disclosure describes a system. The system includes: a cylinder actuator having a cylinder and a piston movable within the cylinder, wherein the piston divides an internal space of the cylinder into a first chamber and a second chamber; a control valve having a valve member disposed therein and one or more actuators that move the valve member when commanded, wherein the valve member controls fluid flow to and from the cylinder actuator, wherein the control valve includes a first pressure sensor that provides sensor information indicative of pressure level in the first chamber, and a second pressure sensor that provides sensor information indicative of pressure level in the second chamber; and a controller performing operations of the method of the first example implementation.

[0009] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, implementations, and features described above, further aspects, implementations, and features will become apparent by reference to the figures and the following detailed description.

BRIEF DESCRIPTION OF THE FIGURES

[0010] The novel features believed characteristic of the illustrative examples are set forth in the appended claims. The illustrative examples, however, as well as a preferred mode of use, further objectives and descriptions thereof, will best be understood by reference to the following detailed description of an illustrative example of the present disclosure when read in conjunction with the accompanying Figures.

[0011] Figure 1 illustrates a valve bank, according to an example implementation.

[0012] Figure 2A illustrates a system, according to an example implementation.

[0013] Figure 2B illustrates a graph showing variation of displacement of a load and pressure levels in chambers of a cylinder actuator of the system of Figure 2A, according to an example implementation.

[0014] Figure 3A illustrates a perspective view of a control valve, according to an example implementation.

[0015] Figure 3B illustrates a cross-sectional view of the control valve of Figure 3 A, according to an example implementation.

[0016] Figure 3C illustrates an exploded perspective view of the control valve of Figure 3A, according to an example implementation.

[0017] Figure 4 is a graph showing variation of pressure levels of in chambers of a cylinder actuator, according to an example implementation.

[0018] Figure 5 is a graph showing first derivative of pressure in chambers of a cylinder actuator with respect to time, according to an example implementation. [0019] Figure 6 illustrates pressure levels, first derivative, and second derivative of pressure levels in chambers of a cylinder actuator, according to an example implementation.

[0020] Figure 7 illustrates determining time at which a piston of a cylinder actuator starts to move, according to an example implementation.

[0021] Figure 8 illustrates determining time at which a piston of a cylinder actuator stops moving, according to an example implementation.

[0022] Figure 9 is a flowchart of a method for determining key events during operation of the system of Figure 2, according to an example implementation.

[0023] Figure 10 is a block diagram of a controller, according to an example implementation.

[0024] Figure 11 is a flowchart of a method for determining diagnostic parameters, according to an example implementation.

DETAILED DESCRIPTION

[0025] Within examples, disclosed herein are assemblies, systems, and methods associated with a valve bank having a plurality of control valves. The disclosed systems and assemblies have an onboard electronic controller configured to control operation of the valve bank. Each control valve may include sensors that monitor operation of the control valve. Particularly, an example control valve can include pressure sensors that indicate pressure level in respective chambers of an actuator (e g., a cylinder actuator). The controller is configured to use pressure sensor information from such pressure sensors to determine various parameters, thereby determining a state of the system and provide predictive diagnostic feedback on the system.

[0026] Figure 1 illustrates a valve bank 10, according to an example implementation. The valve bank 10 includes a first end plate 12, a second end plate 14, and a fluid manifold 16. The first end plate 12 has a supply port 18 configured to be fluidly coupled to a source of fluid (e.g., an air compressor), and has an exhaust port 20 for discharging fluid to an environment of the valve bank 10. Similarly, the second end plate 14 has a supply port 22 configured to be fluidly coupled to the source of fluid and an exhaust port 24 for discharging fluid to the environment of the valve bank 10.

[0027] As shown, the end plates 12, 14 are disposed on opposite ends of the valve bank 10, and they are configured to contain the working fluid in the fluid manifold 16. The supply ports 18, 22 of the end plates 12, 14 receive fluid from the source and provide the fluid to the fluid manifold 16, and thus the end plates 12, 14 can be referred to as supply modules.

[0028] The valve bank 10 includes a plurality of valve sections sandwiched or interposed between the end plates 12, 14. For example, the valve bank includes valve section 26, valve section 28, and valve section 30 among other illustrated valve sections. More or fewer valve sections can be used, and the valve bank 10 is configured to be modular such that valve sections can be added or removed based on the application and how many actuators are controlled by the valve bank 10.

[0029] Each valve section of the valve sections 26-30 may be configured as a discrete modular unit of the valve bank 10, in which each valve section 26-30 includes a corresponding control valve or other functional component of the valve bank 10. In the example implementation of Figure 1, the valve bank 10 includes a control valve 32, a control valve 34, a control valve 36, a control valve 38, etc.

[0030] The control valves may have different configurations. For example, the control valves 32, 36 may have a similar configuration, while the control valves 34, 38 may have a different configuration based on the type of actuator controlled by a respective control valve and the features of such actuator.

[0031] As shown in Figure 1, each control valve of the control valves 32-38 or other functional component is mounted to a corresponding valve fluid manifold such as valve fluid manifold 40, valve fluid manifold 42, and valve fluid manifold 44. The valve fluid manifolds 40-44 operate as respective bases for the valve sections 26-30 described above for example.

[0032] Each valve fluid manifold (e.g., the valve fluid manifold 40) is configured to interface with, and operatively couple to, an adjacent valve fluid manifold (e.g., the valve fluid manifold 42). These valve fluid manifolds 40-44 are fluidly coupled together (in a sealed configuration) to form the fluid manifold 16, which operates as an air manifold and provides a continuous fluid flow path across the various valve fluid manifolds 40, 42, 44. etc. for enabling supply of air to each corresponding control valve (e.g., the control valves 32-38 ). In another example, the fluid manifold 16 may be formed from one or more continuous single piece structures on which the control valves 32-38 or other functional components may be mounted. [0033] As shown in Figure 1, each of the valve fluid manifolds 40-44 has respective workports to couple the valve fluid manifold and its control valve to an external fluid operated device, such as a pneumatic piston-cylinder actuator, for example. For instance, the valve fluid manifold 44 has workports 46 that fluidly couple the valve fluid manifold 44 to an external device to provide fluid to and receive fluid from the device. The workports 46 are fluidly connected to workports of the respective control valve as described below.

[0034] The valve bank 10 further includes an onboard electronic controller mounted to the valve bank 10 and configured to receive sensor signals from the control valves and input commands from an operator, and responsively send command signals to valve actuators of the control valves as described below. The controller also provides diagnostics and feedback information as described in further detail below.

[0035] The controller is an on-board electronic controller that can be mounted to or within any of the control valves or the end plates 12, 14. In an example, the controller can be mounted as one of the modules of the valve bank 10. In an example, the controller can be embedded within one or more of the valve sections or control valves, e.g., the control valve 32 and/or the control valve 36.

[0036] Figure 2A illustrates a system 100, according to an example implementation. The system 100 can include the valve bank 10, which includes an onboard electronic controller depicted as controller 101 configured to control one or more control valves such as control valve 102. The control valve 102 represents any of the control valves (e.g., the control valve 32 or the control valve 36) described above with respect to Figure 1, for example.

[0037] As mentioned above, the valve bank 10 is a pneumatic valve bank that uses compressed air as a working fluid for controlling one or more actuators, such as a cylinder actuator 104 shown in Figure 2A, or other fluid-operated devices on a machine (not shown), such as an automation machine in an assembly plant, for example.

[0038] The cylinder actuator 104 has a cylinder 106 and a piston 108 slidably accommodated in the cylinder 106 and configured to move in a linear direction therein. The piston 108 includes a piston head 110 and a rod 112 extending from the piston head 110 along a central longitudinal axis direction of the cylinder 106. The rod 112 is coupled to a load 114. The load 114 represents an implement or movable member of a machine controlled by the valve bank 10, for example.

[0039] The piston head 110 divides the internal space of the cylinder 106 into a first chamber 116 and a second chamber 118. The first chamber 116 can be referred to as head-side chamber as the fluid therein interacts with the piston head 110, and the second chamber 118 can be referred to as rod-side chamber as the rod 112 is disposed partially therein.

[0040] Figure 3 A illustrates a perspective view of the control valve 102, Figure 3B illustrates a cross-sectional view of the control valve 102, and Figure 3C illustrates an exploded perspective view of the control valve 102, according to an example implementation. The control valve 102 includes a valve body 200 having fluid flow passage(s) that define fluid flow paths therein for fluid communication with a source of fluid (e.g., a compressor or source of compressed air) through the respective fluid manifold of the valve bank 10, and also fluid communication with the cylinder actuator 104.

[0041] The control valve 102 includes a valve member 202 (e.g., spool) that is movable in the fluid flow paths and relative to the valve body 200 to control flow of fluid through the valve body 200. The control valve 102 has an inlet port 201 configured to be fluidly coupled to the source of fluid (e.g., via a respective valve fluid manifold). The control valve 102 also has outlet ports 203, which can be fluidly coupled to a respective exhaust port (e.g., the exhaust port 20 or the exhaust port 24), e.g., via the respective valve fluid manifold.

[0042] The above-mentioned onboard electronic controller (the controller 101) is operably or communicatively coupled to at least one valve actuator, such as valve actuator 204 and valve actuator 206 (shown in Figure 3B), which are respectively disposed at the ends of the valve member 202. The valve actuators 204, 206 are configured to control movement of the valve member 202 in response to commands from the controller 101. The valve actuators 204, 206 can be solenoids actuators, for example. The controller 101 can provide command signals to the valve actuators 204, 206 via connector 205 (e.g., IO-link M12 connector).

[0043] Based on direction of movement of the valve member 202, the valve member 202 allows fluid receive at the inlet port 201 to flow to a first workport 207 or second workport 209. The first workport 207 can be fluidly coupled to the first chamber 116 of the cylinder actuator 104, while the second workport 209 can be fluidly coupled to the second chamber 118, for example. The valve member 202 also allows fluid discharged from the cylinder actuator 104 and provided to one of the workports 207, 209 to flow through one of the outlet ports 203, then through a respective valve fluid manifold and an exhaust port (e.g., the exhaust port 20) of the valve bank 10 to the external environment of the valve bank 10.

[0044] The control valve 102 includes a plurality of sensors. For example, as shown in Figure 3C, the control valve 102 can include a position sensor 208 configured to provide sensor information indicative of a position of the valve member 202.

[0045] The control valve 102 also includes a first pressure sensor 210 and a second pressure sensor

212. The first pressure sensor 210 is configured to provide sensor information indicative of pressure level at the first workport 207 of the control valve 102, where the first workport 207 is fluidly coupled to the first chamber 116 of the cylinder actuator 104. As such, the first pressure sensor 210 provides sensor information indicative of pressure level in the first chamber 116 of the cylinder actuator 104.

[0046] Similarly, the second pressure sensor 212 is configured to provide sensor information indicative of pressure level at the second workport 209 of the control valve 102, where the second workport 209 is fluidly coupled to the second chamber 118 of the cylinder actuator 104. As such, the pressure sensor 212 provides sensor information indicative of pressure level in the second chamber 118 of the cylinder actuator 104. The controller 101 can receive sensor feedback/information from the sensors via the connector 205, for example.

[0047] Referring back to Figure 2A, the pressure sensors 210, 212 are represented schematically by first pressure sensor 132 and second pressure sensor 134, respectively. Although the pressure sensors 132, 134 are shown external to the control valve 102, it should be understood that they could be embedded within the control valve 102 as the pressure sensors 210, 212 shown in Figure 3C.

[0048] Referring to Figures 2A and 3B together, if the controller 101 commands one of the valve actuators 204, 206 of the control valve 102, the valve member 202 shifts in its bore within the valve body 200 in a corresponding direction. Shifting the valve member 202 allows pressurized air received at the inlet port 201 of the control valve 102 to flow through the first workport 207 of the control valve 102 to supply line 120, then to the first chamber 116. In this example, the first chamber 116 can be preferred to as a supply chamber as air is being supplied thereto. The air applies a fluid force on the piston 108, which can cause the piston 108 to move (e.g., to the right in Figure 2), moving the load 114 therewith. [0049] As the piston 108 moves, air is discharged from the second chamber 118, which can be referred to as the exhaust chamber in this example. Discharged air flows through exhaust line 122 back to the second workport 209 of the control valve 102, and air can then be provided through a respective valve fluid manifold to an exhaust port of valve bank 10 be exhausted to an external environment of the valve bank 10 (e.g., the atmosphere).

[0050] As the piston 108 and the load 114 move, pressure levels within the chambers 116, 118 change over time. Thus, based on the sensor information from the position sensor 208 and the pressure sensors 210, 212, the controller 101 can capture variation of displacement of the load 114 and pressure levels in the chambers 116, 118 during operation of the control valve 102 and the cylinder actuator 104.

[0051] Figure 2B illustrates a graph 124 showing variation of displacement of the load 114 and pressure levels in the chambers 116, 118, according to an example implementation. Particularly, line 126 shows the displacement of the load 114 over time (e.g., during a full stroke of the piston 108). Travel or displacement is represented in millimeter (mm) on the right y-axis in the graph 124, while time is represented in seconds on the x-axis.

[0052] Line 128 shows the pressure level (supply pressure) in the first chamber 116 as the load 114 moves over time. Pressure level is represented in pounds per square inch (psi) on the left y- axis in the graph 124. Line 130 shows the pressure level (exhaust pressure) in the second chamber 118 as the load 114 moves over time.

[0053] Based on the pressure levels represented by the lines 128, 130, the controller 101 can detect various parameters and events. These parameters and events can be used by the controller 101 for diagnostic purposes, determining a state of the cylinder actuator 104, and providing predictive maintenance recommendations, for example. [0054] Figure 4 is a graph 300 showing variation of pressure levels of in the chambers 1 16, 118, according to an example implementation. Particularly, the graph 300 shows the lines 128, 130 described above with respect to the graph 124. However, pressure is represented on the y-axis in counts as opposed to psi. The counts correlate (e.g., via a scaling factor) to the pressure level in psi, and the controller 101 can thus convert from counts to psi or vice versa.

[0055] An initial parameter that the controller 101 can determine is time TO at which an electrical command signal is sent from the controller 101 to one of the valve actuators 204, 206 to change the state of the system 100 (e.g., to move the load 114 in a given direction). The controller 101 can determine the time TO by monitoring the electrical signal to coils of the valve actuators 204, 206, for instance. Particularly, the controller 101 can determine TO as the time at which voltage provided to the coil Vcoii) of the valve actuator 204 or the valve actuator 206 exceeds a minimum voltage value ( coiimtn). In other words, TO is detected when V_coii > V_coiimin.

[0056] The controller 101 can then determine time T1 at which the valve member 202 (e.g., the spool) of the control valve 102 shifts. Particularly, T1 is the time at which the valve member 202 of the control valve 102 changes state and allows air to flow. As such, the time T1 can be referred to as the “Event Begin” or “Spool Shift” time. The controller 101 can determine time T1 using first derivative (first-order derivative) of pressure levels in the chambers 116, 118 with respective to time. Such first derivative is the rate of change of pressure with respective to time indicating how fast the pressure level is changing.

[0057] Figure 5 is a graph 400 showing first derivative of pressure in the chambers 116, 118 with respect to time, according to an example implementation. Line 402 represents first derivative of CZDS supply pressure (Ps) in the first chamber 116 with respect to time (— ), and line 404 represents d'ps first derivative of exhaust pressure (Pe) in the second chamber 118 with respect to time —)■

[0058] The controller 101 can determine the time T1 as the time at which the time derivative (~~)

exceeds zero (i.e., has a positive sign: > 0), which is also the same time when the time

derivative ( v— ) is less than zero (i.e., has a negative sign: — < 0). Once — > 0 or — < 0, the dt ’ ^v ° ° dt ’ dt dt controller 101 detects T1 and determines that the valve member 202 has shifted.

[0059] The controller 101 can then detect time T2 at which pressure level in the supply line 120 connecting the control valve 102 to the first chamber 116 begins to increase or build up. As such, the time T2 can be referred to as the “tube filled” or “line filled” time. The controller 101 can determine T2 by monitoring the second derivative (second-order derivative) of pressure levels in the chambers 116, 118 with respective to time indicating how fast the rate of change of pressure is changing.

[0060] Figure 6 illustrates pressure levels, first derivative, and second derivative of pressure levels in the chambers 116, 118, according to an example implementation. Particularly, graph 500 depicts variation of pressure level (Pe) in the second chamber 118 (exhaust chamber) over time, graph 502 depicts variation of the first derivative of pressure level in the second chamber 118 over time, and graph 504 depicts variation of the second derivative of pressure level in the second chamber 118 over time. Similarly, graph 506 depicts variation of pressure level (Ps) in the first chamber 116

(supply chamber) over time, graph 508 depicts variation of the first derivative of pressure level in the first chamber 116 over time, and graph 510 depicts variation of the second derivative of pressure level in the first chamber 116 over time. [0061] The controller 101 can determine T2 based on a change in concavity of the second derivative of pressure with respect to time. Particularly, at time T2, the second derivative of pressure in the first chamber 116 turns from positive to negative, representing the brief point in time where a concave slope turns to a convex slope. The second derivative of the pressure level in the second chamber 118 (exhaust side) does the opposite, where the second derivative of pressure in the second chamber 118 turns from negative to positive.

[0062] In other words, the controller 101 monitors the second derivatives where — > dt d²

0 and < 0, where Ps is the supply pressure in the first chamber 116 and Pe is the exhaust pressure in the second chamber 118. The controller 101 then determines the time T2 at which the

signs of the second derivatives switch such that — < 0 and — > 0.

° dt² dt²

[0063] The controller 101 can then detect time T3 at which the piston 108 starts to move. Particularly, T3 is the time at which the fluid force acting on the piston 108 overcomes static friction (e.g., from seals) and inertia of the load 114, and the piston 108 starts to move.

[0064] Figure 7 illustrates determining time at which the piston 108 starts to move, according to an example implementation. The time T3 relates to the maxima at the end of a long rise. The controller 101 detects the largest change in pressure over time to avoid any fault determination by potential interference. This is done by following the sequence shown in Figure 7.

[0065] Particularly, graph 600 depicts variation of pressure level (Ps) in the first chamber 116 (supply chamber) over time, graph 602 depicts variation of the first derivative of pressure level in the first chamber 116 over time, and graph 604 depicts variation of the second derivative of pressure level in the first chamber 116 over time. To determine T3, the controller 101 counts increments of time (e g., the period of time) during which the following conditions are true: dps d²ps

— — > 0 and 0 dt dt²

[0066] Graph 606 illustrates such counting. The controller 101 keeps counting (e.g., determines the duration or period of time) and updating until the criterion above is not met anymore. When this count exceeds the previous maximum value, the controller 101 updates the value for T3 to be that point in time provided that it also corresponds to the maximum overall rise in pressure level to discard false long slopes that does not correspond to the maximum overall rise in pressure level.

[0067] For example, referring to graph 608, the count associated with slope 610 (stair-like sloping counter) is greater than the count of previous maximum of slope 612. However, the overall rise in pressure associated with the slope 610 is less than a respective overall rise associated with the slope 612.

[0068] Particularly, referring to graph 614, line 616 shows pressure level (the Event Rise) and line 617 shows the maximum rise in pressure level (Maximum Event Rise). A first portion 618 of the line 616 is associated with the slope 612 and a second portion 620 of the line 616 is associated with the slope 610. The rise in pressure of the first portion 618 is greater than the rise in pressure of the second portion 620. As such, despite the count associated with the slope 610 being longer, T3 is not updated because the pressure rise of the first portion 618 is larger than the respective pressure rise of the second portion 620 as indicated by the line 617.

[0069] Thus, T3 is the point in time at which the maximum value of the slope 612 is reached, after which the condition above is not met. T3 associated with the slope 610 does not replace the T3 value associated with the slope 612. Rather, T3 remains associated with the slope 612 as indicated by line 613 in the graph 608, which is the same as the line shown in the graph 606. [0070] The controller 101 can then determine a time T4 at which the piston 108 reaches the end state (e.g., the end of the stroke) and stops moving within the cylinder 106. Thus, T4 is the time when the volume of the first chamber 116 stops increasing so pressure level (Ps) starts building up again in the first chamber 116.

[0071] Figure 8 illustrates determining time at which the piston 108 stops moving, according to an example implementation. Graph 700 depicts variation of pressure level (Ps) in the first chamber 116 (supply chamber) over time, graph 702 depicts variation of the first derivative of pressure level in the first chamber 116 over time, and graph 704 depicts variation of the second derivative of pressure level in the first chamber 116 over time.

[0072] To determine T4, the controller 101 determines the point in time when both the first derivative and the second derivative have a positive sign, signifying the increase in pressure level in the first chamber 116: dps d²ps

—— > 0 and , _n > 0 dt dt²

[0073] To be resilient to noise in the system, the controller 101 detects when the condition is met and counts increments during which the condition is met, and then determines the longest period of increase. Every time this count exceeds the previous maximum value, the controller 101 updates the value for T4 to be that point in time. In graph 706, line 708 represents the longest rising slope or rising time counter, and line 710 represents the maximum rises. The time T4 is shown in graph 712.

[0074] The controller 101 can then determine the time T5 at which the system 100 reaches a static or steady state (i.e., the end of an event). Particularly, this is the time when the system 100 reaches steady state pressure on each of the lines (the supply line 120 and the exhaust line 122). For example, T5 is when the pressure level is atmospheric pressure on the exhaust line 122, and a steady state supply pressure (ps = p_steadystate , where p_steadystate is a substantially constant value), is reached in the supply line 120. The term “substantially constant value” indicates that pressure level remains within a threshold value (e.g., within 5% or within sensor noise margins) from a constant pressure value.

[0075] Figure 9 is a flowchart of a method 800 for determining key events during operation of the system 100, according to an example implementation. Particularly, the method 800 illustrates detecting TO, Tl, and T2 in sequence as the associated events occur in sequence. At block 802, the controller 101 detects TO as described above. Then, at block 804, the controller 101 detects Tl as described above. Then, at block 806, the controller 101 detects T2 as described above.

[0076] Then, at block 808 the controller 101 detects, and continually monitors and updates T3 and T4 as more data points (pressure information from the pressure sensors 210, 212) are received. Particularly, at block 810, the controller 101 detects T3 and accordingly resets the value for T4, because detecting T3 as the time at which the piston 108 starts to move indicates that the previous T4 value associated with the end of the stroke of the piston 108 from a previous cycle is going to change. The controller 101 can then detect the updated value of T4 at block 812 as it detects the piston 108 has reached the end of the stroke as mentioned above.

[0077] Prior to detecting T5, T3 and T4 are not locked and can be updated. Then, the controller 101 detects T5 at block 814, which indicates that this cycle (e.g., stroke of the piston 108 or operation) has ended. Once T5 is detected, the time values T3 and T4 are locked. This process can be repeated for each new cycle and the operations of the method 800 are repeated. [0078] Once the values for TO, Tl, T2, T3, T4, and T5 are determined, the controller 101 can determine key parameters for the performance of the system 100. Particularly, the controller 101 can determine actuator (solenoid) response time (e.g., the period between TO and Tl) of the valve actuators 204, 206. The controller 101 can also determine the response time for the cylinder actuator 104 (e.g., the period between TO and T3). The controller 101 can also monitor the stroke time of valve member 202 or the stroke time of the piston 108 (e.g., the time T4 or the period between T3 and T4).

[0079] Further, these times TO, Tl, T2, T3, T4, and T5 and parameters (e.g., actuator response time, the response time for the piston 108 of the cylinder actuator 104, and the stroke time of the piston 108) can be recorded as a benchmark during normal operation of the system 100 (e.g., during initial operating cycles of the system 100). Over the life of the system 100, deviations from benchmark values may indicate deterioration in components of the system 100. For example, a seal may be deteriorating, causing leakage of air, which may be indicated by deviations in pressure values or indicated by pressure decay compared to benchmark normal operation.

[0080] In examples, the controller 101 can further sense load condition (whether the stroke time increased or the piston 108 slowed down, indicated by an increase in T4 compared to normal operation). The controller 101 can also detect that the piston 108 may have jammed (e.g., stopped in the middle of the stroke) by monitoring pressure levels in the chambers 116, 118 and the time T4, for example. As such, the controller 101 can provide predictive maintenance recommendations and information indicative of the operational state of the system 100 to an operator.

[0081] Figure 10 is a block diagram of the controller 101, according to an example implementation. The controller 101 may have processor(s) 900, a communication interface 902, and data storage 904, each connected to a communication bus 906. The controller 101 may also include hardware to enable communication within the controller 101 and between the controller 101 and a communication bus of the valve bank 10, for example. The hardware may include transmitters, receivers, and antennas, for example.

[0082] The communication interface 902 may be a wireless interface and/or one or more wireline interfaces that allow for both short-range communication and long-range communication to one or more networks or to one or more devices (e.g., to allow communication with a communication bus of the valve bank 10). Such wireless interfaces may provide for communication under one or more wireless communication protocols, Bluetooth, Wi-Fi (e.g., an institute of electrical and electronic engineers (IEEE) 402.11 protocol), Long-Term Evolution (LTE), cellular communications, near- field communication (NFC), and/or other wireless communication protocols. Wireline interfaces may include an Ethernet interface, a CAN network interface, a USB interface, or similar interface to communicate via a wire, a twisted pair of wires, a coaxial cable, an optical link, a fiber-optic link, or other physical connection to a wireline network. Thus, the communication interface 902 may be configured to receive input data from the communication bus of the valve bank 10, and may be configured to send output data to the communication bus. In that manner, the communication interface 902 or other communication ways may enable the controller 101 to receive information from the sensors 208-212 and send command signals to the valve actuators 204, 206, for example.

[0083] The data storage 904 may include or take the form of one or more computer-readable storage media that can be read or accessed by the processor(s) 900. The computer-readable storage media can include volatile and/or non-volatile storage components, such as optical, magnetic, organic or other memory or disc storage, which can be integrated in whole or in part with the processor(s) 900. The data storage 904 is considered non-transitory computer readable media. In some examples, the data storage 904 can be implemented using a single physical device (e.g., one optical, magnetic, organic or other memory or disc storage unit), while in other examples, the data storage 904 can be implemented using two or more physical devices.

[0084] The data storage 904 thus is a non-transitory computer readable storage medium, and executable instructions 908 are stored thereon. The executable instructions 908 include computer executable code. When the executable instructions 908 are executed by the processor(s) 900, the processor(s) 900 are caused to perform the operations of the controller 101 described herein.

[0085] The processor(s) 900 may be a general-purpose processor or a special purpose processor (e.g., digital signal processors, application-specific integrated circuits (ASIC), etc.). The processor(s) 900 may receive inputs from the communication interface 902, and process the inputs to generate outputs that are stored in the data storage 904. The processor(s) 900 can be configured to execute the executable instructions 908 (e.g., computer-readable program instructions) that are stored in the data storage 904 and are executable to provide the functionality of the controller 101 described herein.

[0086] Figure 11 is a flowchart of a method 1000 for determining diagnostic parameters, according to an example implementation. The method 1000 can be implemented by the controller 101, for example.

[0087] The method 1000 may include one or more operations, or actions as illustrated by one or more of blocks 1002-1010. Although the blocks are illustrated in a sequential order, these blocks may in some instances be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation. [0088] In addition, for the method 1000 and other processes and operations disclosed herein, the flowchart shows operation of one possible implementation of present examples. In this regard, each block may represent a module, a segment, or a portion of program code, which includes one or more instructions executable by a processor (e.g., the processor(s) 900 of the controller 101) or the controller 101 for implementing specific logical operations or steps in the process. The program code may be stored on any type of computer readable medium or memory, for example, such as a storage device including a disk or hard drive. The computer readable medium may include a non-transitory computer readable medium or memory, for example, such as computer- readable media that stores data for short periods of time like register memory, processor cache and Random Access Memory (RAM). The computer readable medium may also include non-transitory media or memory, such as secondary or persistent long term storage, like read only memory (ROM), optical or magnetic disks, compact-disc read only memory (CD-ROM), for example. The computer readable media may also be any other volatile or non-volatile storage systems. The computer readable medium may be considered a computer readable storage medium, a tangible storage device, or other article of manufacture, for example. In addition, for the method 1000 and other processes and operations disclosed herein, one or more blocks in Figure 11 may represent circuitry or digital logic that is arranged to perform the specific logical operations in the process.

[0089] At block 1002, the method 1000 includes determining, by the controller 101, an initial time (TO) when a command signal is provided a valve actuator (e.g., the valve actuator 204 or the valve actuator 206) of the control valve 102, wherein the control valve 102 has the valve member 202 disposed therein and movable by the valve actuator, wherein the valve member 202 controls fluid flow to and from the cylinder actuator 104 having the cylinder 106 and the piston 108 movable within the cylinder 106, wherein the piston 108 divides an internal space of the cylinder 106 into the first chamber 1 16 and the second chamber 1 18, and wherein the control valve 102 includes the first pressure sensor 210 that provides sensor information indicative of pressure level in the first chamber 116, and the second pressure sensor 212 that provides sensor information indicative of pressure level in the second chamber 118.

[0090] At block 1004, the method 1000 includes receiving, at the controller 101, sensor information from the first pressure sensor 210 and the second pressure sensor 212.

[0091] At block 1006, the method 1000 includes determining a first derivative and a second derivative of pressure level in the first chamber 116 with respect to time, and a respective first derivative and a respective second derivative of pressure level in the second chamber 118 with respect to time.

[0092] At block 1008, the method 1000 includes determining, by the controller 101 based on the first derivative, the respective first derivative, the second derivative, and the respective second derivative, a plurality of points in time comprising: (i) a time (Tl) at which the valve member is shifted, (ii) a time (T2) at which pressure level in the supply line 120 connecting the control valve 102 to the first chamber 116 begins to increase, (iii) a time (T3) at which the piston 108 begins to move, (iv) a time (T4) at which the piston 108 reaches an end of stroke, and (v) a time (T5) at which pressure level in the supply line 120 reaches a steady state.

[0093] At block 1010, the method 1000 includes determining, based on the initial time (TO) and the plurality of points in time (T2-T5): (i) actuator response time of the valve actuator, (ii) response time of the piston 108, and (iii) a stroke time for the piston 108.

[0094] The method 1000 can further include any of the steps performed by the controller 101 and described throughout herein. [0095] The detailed description above describes various features and operations of the disclosed systems with reference to the accompanying figures. The illustrative implementations described herein are not meant to be limiting. Certain aspects of the disclosed systems can be arranged and combined in a wide variety of different configurations, all of which are contemplated herein.

[0096] Further, unless context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed as component aspects of one or more overall implementations, with the understanding that not all illustrated features are necessary for each implementation.

[0097] Additionally, any enumeration of elements, blocks, or steps in this specification or the claims is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order.

[0098] Further, devices or systems may be used or configured to perform actuators presented in the figures. In some instances, components of the devices and/or systems may be configured to perform the actuators such that the components are actually configured and structured (with hardware and/or software) to enable such performance. In other examples, components of the devices and/or systems may be arranged to be adapted to, capable of, or suited for performing the actuators, such as when operated in a specific manner.

[0099] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those skilled in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide. [00100] The arrangements described herein are for purposes of example only. As such, those skilled in the art will appreciate that other arrangements and other elements (e.g., machines, interfaces, operations, orders, and groupings of operations, etc.) can be used instead, and some elements may be omitted altogether according to the desired results. Further, many of the elements that are described are functional entities that may be implemented as discrete or distributed components or in conjunction with other components, in any suitable combination and location.

[00101] While various aspects and implementations have been disclosed herein, other aspects and implementations will be apparent to those skilled in the art. The various aspects and implementations disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope being indicated by the following claims, along with the full scope of equivalents to which such claims are entitled. Also, the terminology used herein is for the purpose of describing particular implementations only, and is not intended to be limiting.

[00102] Embodiments of the present disclosure can thus relate to one of the enumerated example embodiments (EEEs) listed below.

[00103] EEE 1 is a method comprising: determining, by a controller, an initial time when a command signal is provided a valve actuator of a control valve, wherein the control valve has a valve member disposed therein and movable by the valve actuator, wherein the valve member controls fluid flow to and from a cylinder actuator having a cylinder and a piston movable within the cylinder, wherein the piston divides an internal space of the cylinder into a first chamber and a second chamber, and wherein the control valve includes a first pressure sensor that provides sensor information indicative of pressure level in the first chamber, and a second pressure sensor that provides sensor information indicative of pressure level in the second chamber; receiving sensor information from the first pressure sensor and the second pressure sensor; determining a first derivative and a second derivative of pressure level in the first chamber with respect to time, and a respective first derivative and a respective second derivative of pressure level in the second chamber with respect to time; determining, by the controller based on the first derivative, the respective first derivative, the second derivative, and the respective second derivative, a plurality of points in time comprising: (i) a time at which the valve member is shifted, (ii) a time at which pressure level in a supply line connecting the control valve to the first chamber begins to increase, (iii) a time at which the piston begins to move, (iv) a time at which the piston reaches an end of stroke, and (v) a time at which pressure level in the supply line reaches a steady state; and determining, based on the initial time and the plurality of points in time: (i) actuator response time of the valve actuator, (ii) response time of the piston, and (iii) a stroke time for the piston.

[00104] EEE 2 is the method of EEE 1, further comprising: generating, based on the actuator response time, the response time of the piston, and the stroke time for the piston, diagnostic feedback indicative of performance of the control valve and the cylinder actuator and whether maintenance is required.

[00105] EEE 3 is the method of any of EEEs 1-2, wherein determining the time at which the valve member is shifted comprises: determining the time at which the first derivative of pressure level in the first chamber with respect to time exceeds zero.

[00106] EEE 4 is the method of EEE 3, wherein determining the actuator response time comprises: determining a period between the initial time and the time at which the valve member is shifted.

[00107] EEE 5 is the method of any of EEEs 1-4, wherein determining the time at which pressure level in the supply line begins to increase comprises: determining the time at which the second derivative and the respective second derivative switch signs. [00108] EEE 6 is the method of any of EEEs 1 -5, wherein determining the time at which the piston begins to move comprises: determining a period of time during which the first derivative has a positive sign, while the second derivative has a negative sign.

[00109] EEE 7 is the method of EEE 6, wherein determining the response time of the piston comprises: determining a period between the initial time and the time at which the piston begins to move.

[00110] EEE 8 is the method of any of EEEs 1-7, wherein determining the time at which the piston reaches the end of stroke comprises: determining the time at which both the first derivative and the second derivative have a positive sign.

[00111] EEE 9 is the method of EEE 8, wherein determining the stroke time for the piston comprises: determining a period between the time at which the piston begins to move and the time at which the piston reaches the end of the stroke.

[00112] EEE 10 is the method of any of EEEs 1-9, wherein determining the time at which pressure level in the supply line reaches the steady state comprises: determining the time at which pressure level in the supply line reaches a substantially constant value.

[00113] EEE 11 is a system comprising: a cylinder actuator having a cylinder and a piston movable within the cylinder, wherein the piston divides an internal space of the cylinder into a first chamber and a second chamber; a control valve having a valve member disposed therein and a valve actuator that moves the valve member when commanded, wherein the valve member controls fluid flow to and from the cylinder actuator, wherein the control valve includes a first pressure sensor that provides sensor information indicative of pressure level in the first chamber, and a second pressure sensor that provides sensor information indicative of pressure level in the second chamber; and a controller performing the operations or steps of the method of any of EEEs 1 -10. For example, the operations comprise: determining an initial time when a command signal is provided to the valve actuator, receiving sensor information from the first pressure sensor and the second pressure sensor, determining a first derivative and a second derivative of pressure level in the first chamber with respect to time, and a respective first derivative and a respective second derivative of pressure level in the second chamber with respect to time, determining, based on the first derivative, the respective first derivative, the second derivative, and the respective second derivative, a plurality of points in time comprising: (i) a time at which the valve member is shifted, (ii) a time at which pressure level in a supply line connecting the control valve to the first chamber begins to increase, (iii) a time at which the piston begins to move, (iv) a time at which the piston reaches an end of stroke, and (v) a time at which pressure level in the supply line reaches a steady state, and determining, based on the initial time and the plurality of points in time: (i) actuator response time of the valve actuator, (ii) response time of the piston, an (iii) a stroke time for the piston.

[001141 EEE 12 is the system of EEE 11, wherein the operations further comprise: generating, based on the actuator response time, the response time of the piston, and the stroke time for the piston, diagnostic feedback indicative of performance of the control valve and the cylinder actuator and whether maintenance is required.

[00115] EEE 13 is the system of any of EEEs 11-12, wherein determining the time at which the valve member is shifted comprises: determining the time at which the first derivative of pressure level in the first chamber with respect to time exceeds zero.

[00116] EEE 14 is the system of EEE 13, wherein determining the actuator response time comprises: determining a period between the initial time and the time at which the valve member is shifted. [00117] EEE 15 is the system of any of EEEs 11-14, wherein determining the time at which pressure level in the supply line begins to increase comprises: determining the time at which the second derivative and the respective second derivative switch signs.

[00118] EEE 16 is the system of any of EEEs 11-15, wherein determining the time at which the piston begins to move comprises: determining a period of time during which the first derivative has a positive sign, while the second derivative has a negative sign.

[00119] EEE 17 is the system of EEE 16, wherein determining the response time of the piston comprises: determining a period between the initial time and the time at which the piston begins to move.

[00120] EEE 18 is the system of any of EEEs 11-17, wherein determining the time at which the piston reaches the end of stroke comprises: determining the time at which both the first derivative and the second derivative have a positive sign.

[00121] EEE 19 is the system of EEE 18, wherein determining the stroke time for the piston comprises: determining a period between the time at which the piston begins to move and the time at which the piston reaches the end of the stroke.

[00122] EEE 20 is the system of any of EEEs 11-19, wherein determining the time at which pressure level in the supply line reaches the steady state comprises: determining the time at which pressure level in the supply line reaches a substantially constant value.

Claims

CLAIMS What is claimed is:

1. A method comprising: determining, by a controller, an initial time when a command signal is provided a valve actuator of a control valve, wherein the control valve has a valve member disposed therein and movable by the valve actuator, wherein the valve member controls fluid flow to and from a cylinder actuator having a cylinder and a piston movable within the cylinder, wherein the piston divides an internal space of the cylinder into a first chamber and a second chamber, and wherein the control valve includes a first pressure sensor that provides sensor information indicative of pressure level in the first chamber, and a second pressure sensor that provides sensor information indicative of pressure level in the second chamber; receiving sensor information from the first pressure sensor and the second pressure sensor; determining a first derivative and a second derivative of pressure level in the first chamber with respect to time, and a respective first derivative and a respective second derivative of pressure level in the second chamber with respect to time; determining, by the controller based on the first derivative, the respective first derivative, the second derivative, and the respective second derivative, a plurality of points in time comprising: (i) a time at which the valve member is shifted, (ii) a time at which pressure level in a supply line connecting the control valve to the first chamber begins to increase, (iii) a time at which the piston begins to move, (iv) a time at which the piston reaches an end of stroke, and (v) a time at which pressure level in the supply line reaches a steady state; and determining, based on the initial time and the plurality of points in time: (i) actuator response time of the valve actuator, (ii) response time of the piston, and (iii) a stroke time for the piston.

2. The method of claim 1, further comprising: generating, based on the actuator response time, the response time of the piston, and the stroke time for the piston, diagnostic feedback indicative of performance of the control valve and the cylinder actuator and whether maintenance is required.

3. The method of claim 1, wherein determining the time at which the valve member is shifted comprises: determining the time at which the first derivative of pressure level in the first chamber with respect to time exceeds zero.

4. The method of claim 3, wherein determining the actuator response time comprises: determining a period between the initial time and the time at which the valve member is shifted.

5. The method of claim 1, wherein determining the time at which pressure level in the supply line begins to increase comprises: determining the time at which the second derivative and the respective second derivative switch signs.

6. The method of claim 1, wherein determining the time at which the piston begins to move comprises: determining a period of time during which the first derivative has a positive sign, while the second derivative has a negative sign.

7. The method of claim 6, wherein determining the response time of the piston comprises: determining a period between the initial time and the time at which the piston begins to move.

8. The method of claim 1, wherein determining the time at which the piston reaches the end of stroke comprises: determining the time at which both the first derivative and the second derivative have a positive sign.

9. The method of claim 8, wherein determining the stroke time for the piston comprises: determining a period between the time at which the piston begins to move and the time at which the piston reaches the end of the stroke.

10. The method of claim 1, wherein determining the time at which pressure level in the supply line reaches the steady state comprises: determining the time at which pressure level in the supply line reaches a substantially constant value.

11. A system comprising: a cylinder actuator having a cylinder and a piston movable within the cylinder, wherein the piston divides an internal space of the cylinder into a first chamber and a second chamber; a control valve having a valve member disposed therein and a valve actuator that moves the valve member when commanded, wherein the valve member controls fluid flow to and from the cylinder actuator, wherein the control valve includes a first pressure sensor that provides sensor information indicative of pressure level in the first chamber, and a second pressure sensor that provides sensor information indicative of pressure level in the second chamber; and a controller performing operations comprising: determining an initial time when a command signal is provided to the valve actuator, receiving sensor information from the first pressure sensor and the second pressure sensor, determining a first derivative and a second derivative of pressure level in the first chamber with respect to time, and a respective first derivative and a respective second derivative of pressure level in the second chamber with respect to time, determining, based on the first derivative, the respective first derivative, the second derivative, and the respective second derivative, a plurality of points in time comprising: (i) a time at which the valve member is shifted, (ii) a time at which pressure level in a supply line connecting the control valve to the first chamber begins to increase, (iii) a time at which the piston begins to move, (iv) a time at which the piston reaches an end of stroke, and (v) a time at which pressure level in the supply line reaches a steady state, and determining, based on the initial time and the plurality of points in time: (i) actuator response time of the valve actuator, (ii) response time of the piston, an (iii) a stroke time for the piston.

12. The system of claim 11, wherein the operations further comprise: generating, based on the actuator response time, the response time of the piston, and the stroke time for the piston, diagnostic feedback indicative of performance of the control valve and the cylinder actuator and whether maintenance is required.

13. The system of claim 11, wherein determining the time at which the valve member is shifted comprises: determining the time at which the first derivative of pressure level in the first chamber with respect to time exceeds zero.

14. The system of claim 13, wherein determining the actuator response time comprises: determining a period between the initial time and the time at which the valve member is shifted.

15. The system of claim 11, wherein determining the time at which pressure level in the supply line begins to increase comprises: determining the time at which the second derivative and the respective second derivative switch signs.

16. The system of claim 11, wherein determining the time at which the piston begins to move comprises: determining a period of time during which the first derivative has a positive sign, while the second derivative has a negative sign.

17. The system of claim 16, wherein determining the response time of the piston comprises: determining a period between the initial time and the time at which the piston begins to move.

18. The system of claim 11, wherein determining the time at which the piston reaches the end of stroke comprises: determining the time at which both the first derivative and the second derivative have a positive sign.

19. The system of claim 18, wherein determining the stroke time for the piston comprises: determining a period between the time at which the piston begins to move and the time at which the piston reaches the end of the stroke.

20. The system of claim 11, wherein determining the time at which pressure level in the supply line reaches the steady state comprises: determining the time at which pressure level in the supply line reaches a substantially constant value.