Controlled load abortion in actuator systems

Abstract

A method for unloading a load on a test article in a test system includes determining a load difference in at least one of a calculated load at a valve of an actuator of the test system and a calculated load on a load sensor coupled to the actuator. When the determined load difference reaches a first level, controlled unloading of the load on the test item is initiated via the system controller. When the determined load difference reaches a second level higher than the first level, the load on the test article is interlocked and unloaded via the valve.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 581,465, filed on September 8, 2023, entitled “CONTROLLED LOAD ABORT IN ANACTUATOR SYSTEM,” the contents of which are incorporated herein by reference in their entirety. Background Art

[0003] The following discussion is provided for general background information only and is not intended to be used as an aid in determining the scope of the claimed subject matter.

[0004] In a test system, the test article being tested is very expensive, and in some cases the load on the test article needs to be reduced quickly and effectively to prevent damage to the test article. Summary of the invention

[0005] The Summary and Abstract of the Invention herein are used to introduce a selection of concepts in a simplified form, which are further explained in the Detailed Description below. The Summary and Abstract are not intended to identify key features or essential features of the claimed subject matter, nor are they intended to be used to help determine the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all of the disadvantages noted in the Background.

[0006] In one aspect, a method for unloading a load on a test article in a test system includes determining a load difference in at least one of a calculated load at a valve of an actuator of the test system and a calculated load on a load sensor coupled to the actuator. When the determined load difference reaches a first level, initiating a controlled unloading of the load on the test article via a system controller. When the determined load difference reaches a second level higher than the first level, interlocking unloading of the load on the test article via the valve.

[0007] In some embodiments, commands to the valves are issued by a system controller.

[0008] The load difference may be determined in a variety of ways, and determining the load difference may include comparing a calculated load at the valve to a calculated load at a load sensor, or determining the load difference may include determining a load value of two outputs of the load sensor and designating the load difference as the difference between the load values ​​of the two outputs of the load sensor, or determining the load difference may include comparing the calculated load at the valve to a commanded load at the valve, or determining the load difference may include comparing a load value output of the load sensor to a commanded load at the valve. In some embodiments, the load difference is determined continuously during a flow mode of the test system.

[0009] In some embodiments, initiating controlled unloading via the system controller may include unloading during a flow mode of the test system to unload the load differential to a benign load differential.

[0010] Performing an interlock unloading may include isolating the valve from a hydraulic power source of a test system; measuring pressure on a piston of an actuator; determining a load differential on opposite sides of a piston of a hydraulic actuator coupled to the valve; and ramping the load differential to a benign load differential using a valve.

[0011] The pressure on the piston may be measured after a predetermined delay time after the isolation valve.

[0012] If desired, the load difference may be ramped over a predetermined period of time, and if still desired, the load difference may be ramped linearly over a predetermined period of time.

[0013] In another aspect, a method for interlocking unloading of a test article in a test system by controlling an actuator with a valve includes: isolating a valve from a hydraulic source of the test system; and determining a load difference on opposite sides of a piston of a hydraulic actuator coupled to the valve. Then, using the valve to ramp the load difference to a good load difference.

[0014] In some embodiments, the method may include delaying a predetermined time between isolation and determining the load difference. If desired, the load difference may be ramped over a predetermined time period, and if desired, the load difference may be linearly ramped over a predetermined time period. The load difference may be determined using any of the above methods.

[0015] In yet another aspect, a system for monitoring and unloading a load on a test article includes a hydraulic assembly and a controller. The hydraulic assembly includes: a control valve configured to control a load in a hydraulic actuator coupled to the test article; a pair of pressure sensors configured to detect and transmit pressure in the hydraulic actuator; and an isolation valve for isolating the control valve from the hydraulic pressure. The controller is configured to determine a load difference in at least one of a calculated load at a control valve of a hydraulic actuator of the test system and a calculated load on a load sensor coupled to the hydraulic actuator. When the determined load difference reaches a first level, a controlled unloading of the load on the test article is initiated via the system controller. When the determined load difference reaches a second level higher than the first level, an interlocked unloading of the load on the test article is performed via the control valve.

[0016] In some test system embodiments, the control valve may further include: a controller for receiving pressure; and valve firmware configured to reduce the load differential on the piston of the hydraulic actuator. The valve firmware may be configured to interlock unloading of the load on the test article by: isolating the control valve from the hydraulic source of the test system; determining the load differential on the piston of the hydraulic actuator coupled to the control valve; and ramping the load differential to a benign load differential using the control valve. The load differential may be determined using any of the above methods.

[0017] The valve firmware may be further configured to delay a predetermined time between isolation and determining the load difference. If desired, the valve firmware is further configured to ramp the load difference over a predetermined time period. If further desired, the valve firmware is configured to linearly ramp the load difference over a predetermined time period.

[0018] In some embodiments, the test system may include an electrical controller coupled between the controller and the hydraulic assembly to control power supplied to the valves and hydraulic assembly, receive and transmit signals indicative of loads on the hydraulic actuators and valves, and receive and transmit commands from the controller.

[0019] In yet another aspect, a hydraulic assembly includes a proportional valve configured to control a hydraulic actuator. The proportional valve has a controller for receiving a pressure indicative of a load on a test article and operates valve firmware configured to reduce a load differential on a piston of the hydraulic actuator.

[0020] In some embodiments, the hydraulic assembly may include a pair of pressure sensors configured to detect pressure at the hydraulic actuator and transmit the pressure to the proportional valve.

[0021] The valve firmware can be configured to interlock unloading of the load differential by isolating the proportional valve from the hydraulic power source to the hydraulic assembly; measuring the pressure on the piston of the actuator; determining the load differential on the piston of the hydraulic actuator; and ramping the load differential to a good load differential using the proportional valve. The load differential can be determined using any of the above methods.

[0022] In some embodiments, the valve firmware is further configured to measure the pressure on the piston after a predetermined delay time after isolating the proportional valve. If desired, the valve firmware is further configured to ramp the load difference over a predetermined time period. If further desired, the valve firmware is configured to linearly ramp the load difference over a predetermined time period.

[0023] The hydraulic assembly may include an isolation valve for isolating the proportional valve from the hydraulic power source.

[0024] This summary is not intended to describe each disclosed embodiment or every implementation of the controlled load suspension as described herein. Numerous other novel advantages, features, and relationships will become apparent as the description proceeds. The following figures and description more particularly illustrate illustrative embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a block diagram of a test system according to an embodiment of the present disclosure;

[0026] Figure 2 is a block diagram of a hydraulic assembly according to an embodiment of the present disclosure;

[0027] Figure 3 is a diagram of a test article undergoing testing according to an embodiment of the present disclosure;

[0028] Figure 4A and Figure 4B is a perspective view of a representative hydraulic assembly;

[0029] Figure 5 is a hydraulic circuit diagram of an embodiment of the present disclosure;

[0030] Figure 6 is a flowchart of a method according to an embodiment of the present disclosure; and

[0031] Figure 7 is a flowchart of a method according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0032] Figure 1A system 100 for monitoring and unloading a load on a test article is shown. In one embodiment, the system 100 includes a hydraulic assembly 110 and a system controller 130. In one embodiment, the hydraulic assembly 110 includes a control valve 112 configured to control a load in a hydraulic actuator 120 coupled to the test article. The hydraulic assembly 110 further includes a pair of pressure sensors 114 configured to detect and transmit pressure in the hydraulic actuator 120. An isolation valve 116 is provided to selectively isolate the control valve 112 from a hydraulic source 140 of hydraulic pressure. In this case, the control valve 112 can then locally reduce the load acting on the test article by the actuator 120 in accordance with instructions executed by a local processor in the control valve without further instruction from the system controller 130.

[0033] In one embodiment, the system controller 130 is configured to determine a load difference in at least one of a calculated load at a control valve 112 of a hydraulic actuator 120 of the test system 100 and a calculated load on a load sensor 122 coupled to the hydraulic actuator. In a first method of unloading the load on the test article through each actuator coupled to the test article, the system controller 130 is further configured to initiate a controlled unloading of the load on the test article via the system controller 130 when the determined load difference reaches a first level. The controlled unloading is performed during a flow mode of the system, that is, when the hydraulic source 140 is coupled to the system 100 and the valve operation of each control valve 112 is controlled by the system controller 130. The first level may be referred to as a stop level. If the stop level controlled unloading does not work, the controller 130 is further configured to interlock the load on the test article by sending a command to each control valve 112 of each actuator 120 that needs to unload the load on the test article when the determined load difference reaches a second level higher than the first level, at which time the load on the test article is unloaded using valve controlled unloading or interlocked unloading.

[0034] In one embodiment, the control valve 112 further includes a valve local controller 113 for receiving pressure from the pressure sensor 114 and valve firmware 115, the valve local controller 113 being operable by the local controller 113 and configured to reduce the load difference on the piston of the hydraulic actuator 120. In one embodiment, unloading the load of the actuator by executing the firmware 115 by the valve local controller 113 to control the operation of its associated actuator 120 is performed without further input from the system controller 130. Figure 2 The control valve 112 is shown in more detail in FIG.

[0035] In one embodiment, the firmware 115 is configured to interlock unload the load on the test article. Generally, in one embodiment, this is accomplished by operating the isolation valve 116 (which may be initiated by the system controller 130, or alternatively, by the local controller 113 executing the firmware 115) to isolate the control valve 112 from the hydraulic source 140, the local controller 113 determines the load difference on the piston 124 of the hydraulic actuator 120 coupled to the control valve 112, and operates the control valve 112 to ramp the load difference to a good load difference using the control valve 112. This is done solely in an interlocked situation by the control valve 112 operating the firmware 115 upon receiving an interlock unload command issued by the system controller 130.

[0036] In one embodiment, system controller 130 is an external controller that runs software to operate testing system 100 based on a testing program in system computer 131 which provides a user interface to a user for configuring, operating and monitoring testing of test articles.

[0037] The firmware 115 of the control valve 112 is designed to operate the control valve 112 independently of the system controller 130 to correctly and safely ramp the load difference on the test article to a benign load difference. The test article may be a very expensive device, worth millions of dollars. As used herein, a "benign load difference" is a load difference applied to the test article by one or more actuators connected to the test article that the test engineer believes will not cause any damage to the test article. Therefore, in the "benign load difference" state, some loads from one or more actuators may act on the test article, but the possibility of damage to the test article is not great. A "benign load difference" can also be a load difference that does not apply any non-representative loading to the test article in the test system.

[0038] In the test system 100, a plurality of control valves 112 may be connected to a plurality of hydraulic actuators 120 that provide loads to different locations or portions of the test article. Figure 3 In the exemplary embodiment shown, a series of eight hydraulic actuators 1201, 1202, ..., 1208 are shown, wherein the hydraulic actuators 1201, 1202, ..., 1208 are controlled by hydraulic assemblies 1101, 1102, ..., 1108, respectively. The load sensor 122 of each hydraulic actuator 120 is configured to provide a load signal to the system controller 130. The pressure sensor 114 and the control valve 112 are also configured to provide a load signal to the system controller 130. Typically, each control valve 112 is provided with an isolation valve 116. When the test article is tested according to the desired test procedure, the system controller 130 controls the operation of each isolation valve 116 and the control valve 112 in the "flow mode".

[0039] In one embodiment, the local firmware 115 of each control valve 112 is further configured to delay a predetermined time between isolating the hydraulic assembly 110 from the hydraulic source 140 and determining the load difference. This is done to allow the pressure after isolation to stabilize. In one embodiment, the local firmware 115 is further configured to ramp the load difference over a predetermined time period. The predetermined time period can be programmed into the firmware 115 of the control valve 112, such as when set. The ramp change time can be adjusted by reprogramming the local firmware 115. In one embodiment, the load difference is linearly ramped over a predetermined time period over a predetermined time period; however, this should not be considered limiting. Rather, unloading via a linear ramp change is only one embodiment, where the local processor 113 can use the measured pressure from the pressure sensor 114 measuring the cylinder pressure on each side of the actuator piston to unload according to a non-linear ramp change based on the operation of each valve 112 by the local firmware 115 of the valve. In one embodiment, the control valve 112 is a proportional valve.

[0040] In one embodiment, the system 100 further includes a power controller 150 coupled between the system controller 130 and the hydraulic assembly 110. The power controller 150 is operable to control the power supplied to each control valve 112 and each isolation valve 116 of each hydraulic assembly 110 that controls each actuator 120, receive and transmit signals indicating the load on each hydraulic actuator 120 and each control valve 112, and receive and transmit commands from the system controller 130 for loading the test article and / or unloading the test article at a controlled stop unloading (under the control of the system controller 130, a command signal is sent to each control valve 112) or at an interlock unloading at each actuator 120 (under the control of the local processor 113 executing the local firmware 115 on the control valve 112). The signals to and from the power controller 150 and the system controller 130 are carried in communication lines 152, which may be wired, wireless, or a combination thereof.

[0041] It should be noted that in different figures, the same or similar elements use the same reference numerals.It should also be understood that the terms used herein are used to describe the purpose of the embodiment, and the term is not intended to be restrictive.Unless otherwise indicated, ordinal numbers (e.g., first, second, third, etc.) are used to distinguish or identify different elements or steps in a group of elements or steps, and do not provide sequence or numerical restrictions for the elements or steps of its embodiments.For example, "first", "second" and "third" elements or steps do not necessarily appear in this order, and its embodiments are not necessarily limited to three elements or steps.It should also be understood that, unless otherwise indicated, any label (such as "left", "right", "front", "back", "top", "bottom", "forward", "reverse", "clockwise", "counterclockwise", "up", "down") or other similar terms (such as "upper", "lower", "back", "front", "vertical", "horizontal", "near side", "distal side", "middle", etc.) are used for convenience, and are not intended to, for example, imply any specific fixed position, orientation or direction.Alternatively, such labels are used to reflect, for example, relative position, orientation or direction. It is also to be understood that the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0042] Now refer to Figure 2 , schematically illustrates a hydraulic assembly 110 that includes a control valve 112 configured to control a hydraulic actuator such as 120. In one embodiment, the control valve 112 is a proportional valve having its own local controller 113 and local firmware 115 loaded therein to control the operation of the control valve 112 during an interlock unloading operation.

[0043] In one embodiment, the hydraulic assembly 110 further includes a pair of pressure sensors 114 (one for each port of the actuator 120) configured to detect pressure on opposite sides of the piston in each actuator and transmit a signal indicative of the measured pressure at the hydraulic actuator 120. The controller 113 of the control valve 112 is configured to receive the measured pressure indicative of the load on the test article. In one embodiment, the control valve 112 operates the valve local firmware 115 as discussed above, which is configured to remove the load difference on the piston of the hydraulic actuator to a benign load difference for each associated actuator 120 in an interlock unload condition.

[0044] As discussed above, in one embodiment, the local firmware 115 is configured to interlock unloading for a load differential that exists across the piston of the associated actuator. In one embodiment, this is performed by isolating the control valve 112 from the hydraulic source 140 that provides hydraulic power to the hydraulic assembly 110. After isolation, the pressure on the piston (e.g., piston 124) of the actuator (e.g., hydraulic actuator 120) is measured, such as by the pressure sensor 114. The load differential on the piston 124 of the hydraulic actuator 120 is determined, and the load differential is ramped to a good load differential using the control valve 112. As already discussed, for interlock unloading, the operation of the control valve 112 is independent and relies on its local controller 113 and firmware 115 to ramp the load differential to a good load differential without initiating the interlock unloading under the supervision or control of the system controller 130.

[0045] As already discussed, in one embodiment, the local firmware 115 is further configured to measure the hydraulic pressure on opposite sides of the piston after a predetermined delay time after isolating the control valve 112. The local firmware 115 is further configured to ramp the load difference present on each associated actuator 120 over a predetermined time, such as a linear ramp. In one embodiment, the hydraulic assembly 110 further includes an isolation valve 116 for isolating the control valve 112 from the hydraulic power source 140. In one embodiment, the isolation valve 116 is a solenoid valve.

[0046] Under normal operating conditions, the test system 100 will have hydraulic pressure provided to the actuator 120 by the hydraulic source 140. The test system 100 may have many hydraulic actuators 120, each coupled to the hydraulic source 140 through a manifold or other hydraulic distribution system. In one embodiment, the test system 100 includes a plurality of test subsystems, each subsystem including a plurality of hydraulic actuators. In one embodiment, each subsystem includes eight hydraulic actuators 120, each hydraulic actuator having an associated control valve 112 and isolation valve 116, and each subsystem having an associated connection through a power controller 150, which contains a power supply for the subsystem and the ability to relay valve and actuator information to the system controller 130. In one embodiment, the system controller 130 is a test system controller, such as the Flex Test 200 controller manufactured by MTS Systems Corporation of Eden Prairie, Minnesota, USA.

[0047] The test system 100 mitigates the risk of non-representative loading or loading that may damage the test article being tested by the test system 100 in a number of ways. The calculated load of the control valve 112 of the subsystem is fed to the system controller 130 through the power controller 150. The system controller 130 determines the potential load difference of one or more actuators 120 that may not operate correctly in various ways, as further described herein. If there is a possible test article load difference, the system controller 130 can initiate a controlled unloading, referred to as a stop level or simply a "stop situation" above. In the stop situation, the system controller 130 controls and uses normal operations in the test system hydraulic system to reduce the load difference while still providing hydraulic power. As is known in the art, the failure of certain components in the test system 100 may trigger a stop or controlled unloading. However, monitoring the calculated load and command load on the pressure sensor and the components of the test system 100, and / or the measured load from the associated load sensor 122, may also cause the system controller 130 to issue a stop command.

[0048] If the stop command is unsuccessful, i.e., the load differential on the test article is not reduced or mitigated, it indicates that there is a potential problem with the integrity of the system controller 130 or the control loop of the test system 100 when executing the stop command. In this case, or if the load differential continues to increase to a higher second level that exceeds the stop level, the system controller 130 commands an interlock to one or more actuators 120, but typically the command is initiated for all actuators 120. In conventional interlocks, non-representative or uneven unloading of the load on the test article may occur, potentially causing damage to the test article. In an embodiment of the present disclosure, the interlock enables controlled (e.g., linear) unloading of the load differential on the test article by using a control valve 112 such as controlled by each local processor 113, and each local processor 113 operates completely on its own after receiving the interlock command under the interlock condition. The local firmware 115 executed by each local processor 113 does not need to use the system controller 130, and typically only needs to initiate an interlock command to each control valve 112 to control the unloading of the load differential to a benign load differential.

[0049] Reference Figure 3, a subsystem of eight hydraulic assemblies 1101, 1102, ..., 1108 is shown. Each hydraulic assembly 1101, 1102, ..., 1108 is coupled to a manifold or the like of a hydraulic source 140, to its own hydraulic actuator 1201, 1202, ..., 1208, and to a power controller 150 via a communication line 152. Load sensors 1221, 1222, ..., 1228 are coupled to each associated actuator 1201, 1202, ..., 1208 and the test article 300 to transmit the load from each actuator 120. It should be noted that each load sensor 1221, 1222, ..., 1228 may provide one or more (e.g., two) signals to the system controller 130 indicative of the measured load thereon. The control valves 112 of the hydraulic assemblies 1101, 1102, ..., 1108 are coupled to the hydraulic source 140 and the electrical controller 150 and receive instructions from the system controller 130 through the electrical controller 150 to perform the desired loading of the test article 300 in normal operation, to perform a stop condition as described above, or to initiate an interlock unloading at each actuator 1201, 1202, ..., 1208 via its associated control valve 112. When interlocked, each valve of the hydraulic assemblies 1101, 1102, ..., 1108 is isolated from the hydraulic source 140 and operates independently according to its local firmware 115 to ramp the load differential on its corresponding load sensor / actuator to a benign load differential.

[0050] Figure 4A and Figure 4B A representative design of a hydraulic assembly 110 configuration is shown in FIG. The hydraulic assembly 110 is configured with a manifold 118 to which hydraulic lines can be connected. In one embodiment, a control valve 112, a pressure sensor 114, and an isolation valve 116 are mounted to the manifold 118. In one embodiment, the isolation valve 116 is activated by a solenoid.

[0051] Figure 5A hydraulic circuit 500 is shown for providing hydraulic power to the control valves 112 and the hydraulic actuators 120. The hydraulic source 140 has a pressure line 142 and a return line 144 for providing hydraulic fluid to each control valve 112 and returning hydraulic fluid from each control valve 112 to the hydraulic source. When the interlock unloading is activated, the isolation valve 116 isolates the pressure line 142, thereby isolating the hydraulic source 140 from the control valve 112, the pressure sensor 114, and the hydraulic actuator 120. In one embodiment, the isolation valve is activated by a solenoid. Once the isolation valve 116 isolates the control valve 112, the sensor 114, and the hydraulic actuator 120, the local firmware 115 executed on the local processor 113 in the control valve 112 determines the load difference present in the associated actuator 120 and operates to ramp the load difference to a good load difference for that actuator 120 without further input from the system controller 130. Check valves 502 , 504 , and 506 help regulate or control pressure in hydraulic system 500 .

[0052] Figure 6 6 shows a method 600 for unloading a load on a test article in a test system. The method 600 includes determining at box 602 whether there is a possible test article load difference in at least one of a calculated load at a valve of an actuator of the test system and a calculated load on a load sensor coupled to the actuator, or determining whether there is other situation that requires a stop condition to be performed by the system controller 130. For an undesirable load on the test article, the method 600 further includes at box 604 initiating a controlled unloading of the load on the test article via the system controller when the determined load difference reaches a first level. The first level may be referred to as a stop level or a stop condition. The stop condition initiates a controlled unloading of the load on the test article using the system controller. However, if the controlled unloading performed via the system controller 130 in the stop condition is deemed unsatisfactory, then at box 606, when the determined load difference reaches a second level higher than the first level, interlocking the load on the test article via each valve of each actuator, and thereafter unloading the load on the test article using valve controlled unloading or interlocking unloading. In one embodiment, commands are issued to each valve via system controller 130 .

[0053] There may be multiple potential load difference determinations for determining the first level of stop and the first level of correction, as well as the second load difference level of interlock. One or more different criteria may be used to determine or ascertain whether there is a potentially undesirable load difference on the test article. In one embodiment, the determination includes comparing the command load (the desired load from the actuator) controlled by the associated valve with the measured load from the associated load sensor. In another embodiment, determining the load difference includes determining whether the load values ​​of the two outputs of the above-mentioned load sensor are different and specifying the determined load difference as the difference between the load values ​​of the two outputs of the load sensor. In another embodiment, determining whether there is a load difference includes comparing the calculated load at the valve with the command load at the valve. In yet another embodiment, determining the load difference includes comparing the load value output of the load sensor with the command load at the valve.

[0054] In one embodiment, load differentials are continuously determined during the flow mode of the test system (i.e., during normal operation of the test system 100) in order to perform the desired test on the test article. Each potential load differential can be monitored, and the load differential in any method reaching a first stop level triggers a controlled unloading stop condition via a command issued by the system controller 130 in response to the determined load differential. When the stop or controlled unloading does not reduce the load differential and the load differential rises to a second level higher than the first level, the system controller 130 commands an interlock unloading. In one embodiment, interlock unloading at each of the one or more actuators 120 (typically all actuators) includes isolating each control valve 112 from the hydraulic power source 140 of the test system and measuring the pressure on opposite sides of the piston of the actuator 120, for example, via a pressure sensor 114 coupled to each port of the actuator 120. The load differential on both sides of the piston is determined, and the load differential is ramped to a good load differential using the control valve 112 under the control of the local processor 113 executing the local firmware 115. In one embodiment, the pressure on the piston is measured after a predetermined delay time after valve isolation so that the load on the test article 300 can be accurately ascertained. In one embodiment, the load differential is ramped over a predetermined period of time, and in one embodiment, the load differential is ramped linearly over a predetermined period of time.

[0055] according to Figure 7The method 700 shown performs an interlock unloading of a test article in a test system. The method 700 involves the operation of each hydraulic circuit 500 in the event that the system controller 130 issues an interlock command. The method includes: at box 702, in one embodiment, isolating the control valve 112 from the hydraulic source 140 of the test system by operating the isolation valve 116; and at box 704, determining the load difference on opposite sides of the piston of the actuator coupled to the valve. At box 706, the load difference is ramped to a good load difference using the valve. The method 700 may further include delaying a predetermined time between isolation and determining the load difference. It should also be noted that, typically, the initial load difference present for each actuator measured by the pressure sensor 114 is stored in the memory of the control valve 112 and used by the local processor 113 executing the local firmware 115. The initial pressure is used to find out the load difference expected during the ramp change to the good load difference. The local processor continuously receives the measured pressure from the pressure sensor 114 so that the control valve 112 is controlled to achieve the desired reduction in the load difference during unloading. As already discussed, the load difference can be ramped over a predetermined time, and the load difference can be linearly ramped, for example, over a predetermined time period. It should be noted that in one embodiment, the predetermined delay and the predetermined time period are substantially the same for all actuators 120 connected to the test article. This is also advantageous for the loads from the actuators 120 to each begin substantially simultaneously and to decrease at a percentage rate in accordance with the unloading instructions stored in the local firmware 115, even if each control valve 112 is operated independently. Therefore, unloading across the entire test article occurs across the test article in a somewhat balanced manner so as to reduce the possibility of damaging the test article during unloading.

[0056] Thus, embodiments of the present disclosure provide methods and systems for controlled unloading of a load differential on a test article in a testing system when the load differential reaches a first stop level, and safe linear interlock unloading if the load differential reaches a second, higher interlock level.

[0057] The subject matter disclosed above should be considered illustrative and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments that fall within the scope of the present disclosure. Therefore, to the maximum extent allowed by law, the scope of the present disclosure will be determined by the broadest permissible interpretation of the appended claims and their equivalents and shall not be restricted or limited to the above detailed description.

Claims

1. A method for unloading a load on a test article in a test system, the method comprising: determining a load difference in at least one of a calculated load at a valve of an actuator of the test system and a calculated load on a load sensor coupled to the actuator; initiating, via a system controller, a controlled unloading of the load on the test article when the determined load differential reaches a first level; as well as When the determined load difference reaches a second level higher than the first level, the load on the test article is interlockedly unloaded via the valve.

2. The method of claim 1, wherein: Commands are issued to the valves by the system controller.

3. The method of claim 1, wherein: Determining the load difference includes comparing a calculated load at the valve to a calculated load at the load sensor.

4. The method of claim 1, wherein: Determining the load difference includes determining load values ​​of two outputs of the load sensor and designating the load difference as a difference between the load values ​​of the two outputs of the load sensor.

5. The method of claim 1, wherein: Determining the load difference includes comparing a calculated load at the valve to a commanded load at the valve.

6. The method of claim 1, wherein: Determining the load difference includes comparing a load value output by the load sensor to a commanded load at the valve.

7. The method according to any one of claims 1 to 6, wherein: The load difference is determined continuously during a flow mode of the test system.

8. The method according to any one of claims 1 to 7, wherein: Initiating the controlled unloading via the system controller includes unloading during a flow mode of the test system to unload the load differential to a benign load differential.

9. The method according to any one of claims 1 to 8, wherein: The interlock unloading comprises: isolating the valve from a hydraulic power source of the test system; measuring the pressure on the piston of the actuator; determining a load differential on opposite sides of a piston of the actuator coupled to the valve; and The load differential is ramped to a good load differential using the valve.

10. The method of claim 9, wherein: The pressure on the piston is measured after a predetermined delay time after isolating the valve.

11. The method of claim 9, wherein: The load difference is ramped over a predetermined period of time.

12. The method of claim 11, wherein: The load difference is linearly ramped over the predetermined period of time.

13. A method for interlocking unloading of a test article in a test system by controlling an actuator with a valve, the method comprising: isolating the valve from a hydraulic source of the test system; determining a load differential on opposite sides of a piston of the actuator coupled to the valve; as well as The load differential is ramped to a good load differential using the valve.

14. The method of claim 13, further comprising delaying a predetermined time between isolating and determining the load difference.

15. The method of claim 13, wherein: The load difference is ramped over a predetermined period of time.

16. The method of claim 15, wherein: The load difference is linearly ramped over the predetermined period of time.

17. A test system for monitoring and unloading a load on a test article, the test system comprising: A hydraulic assembly, the hydraulic assembly comprising: a control valve configured to control a load in a hydraulic actuator coupled to the test article; a pair of pressure sensors configured to detect and transmit pressure in the hydraulic actuator; and an isolation valve, the isolation valve being used to isolate the control valve from the hydraulic pressure; A controller, the controller being configured to: determining a load difference in at least one of a calculated load at a control valve of a hydraulic actuator of the test system and a calculated load on a load sensor coupled to the hydraulic actuator; initiating, via a system controller, a controlled unloading of the load on the test article when the determined load differential reaches a first level; and When the determined load difference reaches a second level higher than the first level, the load on the test article is interlockedly unloaded via the control valve.

18. The test system of claim 17, wherein: The control valve further includes: a controller for receiving the pressure; and valve firmware configured to reduce a load difference on a piston of the hydraulic actuator.

19. The test system of claim 18, wherein: The valve firmware is configured to interlock and unload the load on the test article by: isolating the control valve from a hydraulic source of the test system; determining a load differential on a piston of the hydraulic actuator coupled to the control valve; and The load differential is ramped to a good load differential using the control valve.

20. A hydraulic assembly comprising: A proportional valve configured to control a hydraulic actuator, the proportional valve having a controller for receiving a pressure indicative of a load on a test article, the proportional valve operating valve firmware configured to reduce a load differential on a piston of the hydraulic actuator.

21. The hydraulic assembly of claim 20, further comprising a pair of pressure sensors configured to detect pressure at the hydraulic actuator and transmit the pressure to the proportional valve.

22. A hydraulic assembly as claimed in any one of claims 20 to 21, wherein: The valve firmware is configured to interlock unloading of the load difference by: isolating the proportional valve from a source of hydraulic power to the hydraulic assembly; measuring the pressure on the piston of the actuator; determining a differential load on a piston of the hydraulic actuator; as well as The load difference is ramped to a good load difference using the proportional valve.

23. A hydraulic assembly as claimed in any one of claims 20 to 22, wherein: The valve firmware is further configured to measure the pressure on the piston after a predetermined delay time after isolating the proportional valve or is further configured to ramp the load difference over a predetermined period of time.

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