Dynamic testing system hydraulic actuator speed control

Abstract

To provide methods of controlling a hydraulic actuator of a test station of a dynamic testing system, and a test station configured to practice the methods.SOLUTION: A flow rate control circuit is set in one of a first state and a second state based on a flow rate attenuation signal. A differential signal is delivered to a control valve 132 as an actuator command signal when the flow rate control circuit is in the first state. An attenuated differential signal is delivered to the control valve as the actuator command signal when the flow rate control circuit is in the second state. A flow rate and a direction of the hydraulic fluid flow are controlled based on the actuator command signal. The flow rate corresponding to the attenuated differential signal is less than the flow rate corresponding to the differential signal.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 535,910, filed August 31, 2023, the contents of which are incorporated herein by reference in their entirety.

[0002] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate generally to a test station of a dynamic testing system, and more specifically, to speed control of a hydraulic actuator of the test station. [Background technology]

[0003] Dynamic testing systems, such as those developed by MTS Systems Corporation, include test stations that perform various tests by applying loads and displacements to a test object using hydraulic actuators. Test stations may include, for example, a vehicle test station that applies simulated driving situations to a moving vehicle, or a building test station that applies simulated seismic activity to a building.

[0004] The actuators of the test station are driven by a flow of actuating fluid, and the actuation performed by each actuator is performed using a control valve (e.g., a proportional control valve) that regulates the flow rate and direction of the actuating fluid flow through the actuator.

[0005] For safety reasons, personnel are typically prevented from entering the test station while tests are being performed. An inlet safety valve, which controls the high pressure flow of hydraulic fluid to the test station, may be placed in a low flow state that limits the flow of hydraulic fluid to the test station and its actuators. As a result, when the safety valve is in the low flow state, the speed at which the actuators move is greatly reduced, which may allow personnel to safely enter the test station and, for example, inspect the test operations being performed by the actuators. Summary of the Invention [Problem to be solved by the invention]

[0006] Such inlet safety valves inherently result in pressure drops within the system that must be overcome during normal operation through higher pressurization of the working fluid, resulting in reduced energy efficiency. Moreover, such inlet safety valves typically only provide a single layer of safety from actuators that are driven faster than desired. [Means for solving the problem]

[0007] An embodiment of the disclosure relates to a method of controlling a hydraulic actuator of a test station of a dynamic test system, and a test station configured to perform the method. The method is performed in a test station including a hydraulic actuator configured to drive an actuation under test using a flow of actuating fluid, a control valve, an actuation sensor, a test controller, an actuator controller, and a flow control circuit. In the method, a feedback signal indicative of a parameter of the actuation is generated using the actuation sensor. A reference signal indicative of a desired actuation based on a test program is generated using the test controller. A differential signal based on a difference between the reference signal and the feedback signal is generated using the actuator controller. The flow control circuit is set to one of a first state and a second state based on the flow damping signal. When the flow control circuit is in the first state, the differential signal is sent to the control valve as an actuator command signal. When the flow control circuit is in the second state, the damped differential signal is sent to the control valve as an actuator command signal. A flow rate and a direction of the actuating fluid flow are controlled based on the actuator command signal. A flow rate corresponding to the damped differential signal is less than a flow rate corresponding to the differential signal.

[0008] In some embodiments of the method, the flow rate corresponding to the attenuated differential signal is a non-zero flow rate.

[0009] In some embodiments of the method, the non-zero flow rate is less than about 20% of the flow rate corresponding to the differential signal.

[0010] In some embodiments of the method, the non-zero flow rate limits movement of an actuator rod of a hydraulic actuator driving the actuation to less than about 15 millimeters per second.

[0011] In some embodiments of the method, the flow rate corresponding to the attenuated differential signal is substantially zero, substantially fixing the position of the actuator rod that drives the actuation.

[0012] In some embodiments of the method, the hydraulic actuator includes a cylinder and an actuator rod with a piston housed within the cylinder, and movement of the piston and actuator rod relative to the cylinder drives the actuation.

[0013] In some embodiments, the control valve comprises a valve housing including an inlet port connected to a supply of high pressure actuating fluid, an outlet port connected to a low pressure return reservoir, a first port connected to a first working volume defined by an interior of the cylinder and the piston, and a second port connected to a second working volume defined by an interior of the cylinder and the piston. The control valve may also comprise a valve body contained within the housing, the valve body having a position for directing a flow of actuating fluid received at the inlet port to one of the first port and the second port or to other than the first port and the second port to control a flow rate of the actuating fluid flow, and a valve body driver configured to adjust a position of the valve body based on an actuator command signal.

[0014] In some embodiments of the method, the valve body actuator comprises a servo or a solenoid.

[0015] In some embodiments of the method, the valve body comprises a spool or a piston.

[0016] In some embodiments of the method, the actuation includes movement of the test object, the actuation sensor includes a displacement sensor, and the feedback signal is indicative of the displacement or movement of the test object.

[0017] In some embodiments of the method, the actuation includes a force on the test object, the actuation sensor includes a load cell, and the feedback signal is indicative of the force applied to the test object.

[0018] In some embodiments, the method includes generating the flow decay signal using a test controller.

[0019] In some embodiments, the method includes attenuating the differential signal using a flow control circuit to form an attenuated differential signal.

[0020] One embodiment of the test station includes a hydraulic actuator configured to drive an actuation under test using a flow of actuating fluid, a control valve configured to control the flow rate and direction of the actuating fluid flow and the actuation in response to an actuator command signal, an actuation sensor configured to generate a feedback signal indicative of a parameter of the actuation, a test controller configured to generate a reference signal corresponding to a desired actuation based on a test program, an actuator controller configured to generate a differential signal based on a difference between the reference signal and the feedback signal, and a flow control circuit. The flow control circuit has a first state in which the flow control circuit is configured to send the differential signal as the actuator command signal to the control valve, and a second state in which the flow control circuit is configured to send a damped differential signal as the actuator command signal to the control valve. The flow control circuit transitions from the first state to the second state in response to the flow damped signal. A flow rate corresponding to the damped differential signal is less than a flow rate corresponding to the differential signal.

[0021] In some embodiments of the present test station, the flow rate corresponding to the attenuated differential signal is a non-zero flow rate.

[0022] In some embodiments of the present test station, the non-zero flow rate is less than about 20% of the flow rate corresponding to the differential signal.

[0023] In some embodiments of the present test station, the non-zero flow rate limits the movement of the actuator rod of the hydraulic actuator driving the actuation to less than about 15 millimeters per second.

[0024] In some embodiments of the present test station, the flow rate corresponding to the attenuated differential signal is substantially zero and fixes the position of the actuator rod that drives the actuation.

[0025] In some embodiments of the present testing station, the hydraulic actuator comprises a cylinder and an actuator rod with a piston housed within the cylinder, where movement of the piston and actuator rod drives the actuation.

[0026] In some embodiments, the control valve comprises a valve housing including an inlet port connected to a supply of high pressure actuating fluid, an outlet port connected to a low pressure return reservoir, a first port connected to a first working volume defined by an interior of the cylinder and the piston, and a second port connected to a second working volume defined by an interior of the cylinder and the piston. The control valve may also comprise a valve body contained within the housing, the valve body having a position for directing a flow of actuating fluid received at the inlet port to one of the first port and the second port or to other than the first port and the second port to control a flow rate of the actuating fluid flow, and a valve body driver configured to adjust a position of the valve body based on an actuator command signal.

[0027] In some embodiments of the present test station, the valve body actuator comprises a servo or a solenoid.

[0028] In some embodiments of the present test station, the valve body comprises a spool or piston.

[0029] In some embodiments of the present testing station, the actuation includes movement of the test object, the actuation sensor includes a displacement sensor, and the feedback signal is indicative of the displacement or movement of the test object.

[0030] In some embodiments of the testing station, the actuation includes a force on the test object, the actuation sensor includes a load cell, and the feedback signal is indicative of the force applied to the test object.

[0031] This Summary herein is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all of the shortcomings discussed in the Background. [Brief description of the drawings]

[0032] [Figure 1] 1 is a simplified diagram of an example dynamic testing system according to an embodiment of the present disclosure.

[0033] [Diagram 2] 1 is a schematic diagram of an example test station according to an embodiment of the present disclosure. [Diagram 3] 1 is a schematic diagram of an example test station according to an embodiment of the present disclosure.

[0034] [Figure 4] FIG. 2 is a diagram of an example of a flow control circuit according to an embodiment of the present disclosure.

[0035] [Diagram 5] 2 is a simplified diagram of an example of a differential signal according to an embodiment of the present disclosure.

[0036] [Figure 6]2 is a simplified diagram of an example of an attenuated differential signal, according to an embodiment of the present disclosure. [Figure 7] 2 is a simplified diagram of an example of an attenuated differential signal, according to an embodiment of the present disclosure.

[0037] [Figure 8] 4 is a flow chart illustrating a method of controlling a hydraulic actuator of a test station according to an embodiment of the present disclosure.

[0038] [Figure 9] 2 is a simplified diagram of an example controller according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] The embodiments of the present disclosure are described more fully hereinafter with reference to the accompanying drawings. Elements identified using the same or similar reference numerals refer to the same or similar elements. However, various embodiments of the present disclosure may be embodied in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0040] The functions described herein may be performed by a single controller, multiple controllers, or at least one controller. As used herein, when one or more functions are described as being performed by a "controller", e.g., a particular controller, one or more controllers, or at least one controller, the embodiment includes the performance of the function(s) by a single controller or processor, or multiple controllers or processors, unless otherwise specified. Furthermore, as used herein, when multiple functions are performed by at least one controller, all of the functions may be performed by a single controller, or some functions may be performed by one controller and other functions may be performed by another controller. Thus, the performance of one or more functions by at least one controller does not require that all of the functions be performed by each of the controllers.

[0041] 1 is a simplified diagram of an example dynamic testing system 100 according to an embodiment of the present disclosure. The testing system 100 can include one or more testing stations 102, each of which can be configured to perform a test or situation simulation by applying forces and / or displacements to a test object 103 (e.g., a vehicle, a building, etc.) using a hydraulic actuator 104 driven by a flow of a working fluid 106.

[0042] The stream 106 may be provided based on a working fluid stream 108 generated by one or more fluid power units (HPUs) 110. The system 100 may include an accumulator 116 that stores pressurized working fluid received from the HPUs 110 and delivers a working fluid stream 118 that may be used to form the stream 106 provided to the test station 102. The system 100 may include a distributor 120 that receives the working fluid stream from the HPUs 110 and / or the accumulator 116 and distributes the working fluid stream 106 to the test station 102. Other configurations of the system 100 may be used to provide the requested working fluid stream 106 to the test station 102.

[0043] The system 100 may be a closed system in which the low pressure working fluid flow 106 ′ discharged from the test station 102 returns, for example, as a mixed return flow 124 through the hydraulic distribution system 120 back to the HPU 110 .

[0044] The system controller 126 may operate to control various aspects of the system 100 including the function of the HPU 110, the valving (e.g., the accumulator and / or distributor valving), and / or other aspects of the system 100 to supply the required working fluid flow 106 to the test station 102.

[0045] 2 is a schematic diagram of an example of a test station 102, according to an embodiment of the present disclosure. As described above, the test station 102 includes a number of hydraulic actuators 104, such as hydraulic actuators 104A-104D, configured to apply forces and / or drive motion to a test object 103. Each of the hydraulic actuators 104A-104D is driven by a corresponding flow portion 106A-106D of a working fluid stream 106 generated by one or more of the fluid power units 110 (FIG. 1).

[0046] Each test station 102 may include a test station controller 130 generally configured to perform tests on the test object 103 based on execution of a test program stored, for example, on a non-transitory computer readable medium. The test station controller 130 controls the actuators 104 to apply forces and / or motions to the test object 103 in a conventional manner in response to the execution of the test program through control of the actuating fluid flows 106A-106D using corresponding control valves 132.

[0047] The computing device 134 may be configured to generate a graphical user interface that allows a user to interact with and / or control the test station 102, execute test programs, view data, and / or perform other tasks, such as through a series of communications with the test station controller 130.

[0048] One or more safety inlet valves 136, such as solenoid valves, can control the flow of high pressure actuating fluid flow 106 to the test station 102 in response to a control signal (e.g., an emergency stop) from the test station controller 130, the system controller 126, or another suitable device. Each safety inlet valve 136 has a fully open state that provides a substantially unrestricted path for movement of the actuating fluid flow 106 to the test station 102. The valves 136 also have a closed or substantially closed state in which the valves 136 block or substantially block the actuating fluid flow 106 to the test station 102. The solenoids of the valves 136 can have a default or de-energized state that corresponds to the closed or substantially closed state.

[0049] When the safety inlet valve 136 is in a substantially closed state, an opening in the valve 136 allows the actuating fluid stream 106 to travel to the test station 102. However, the flow rate of the stream 106 is substantially restricted. This limits the flow rate of the actuating fluid 106 to the test station 102 and the actuator 104, regardless of the setting of the control valve 132, thereby limiting the speed at which the actuator 104 can move.

[0050] The safety inlet valve 136 may be set to a substantially closed state by the test station controller 130, the system controller 126, or another controller of the system 100, for example, in response to a detected malfunction or before an operator enters the test area in which the actuator 104 and test subject 103 are located. The one or more safety inlet valves 136 thus provide a level of safety for the test station 102.

[0051] A greater degree of safety at the test station is desirable, such as a safety measure to ensure that the maximum speed at which the actuator moves is below a desired threshold limit when a malfunction is detected or an operator enters the test area. However, providing redundant safety inlet valves 136 in system 100 is generally undesirable because valves 136 introduce a pressure drop in stream 106 that must be overcome through pressurization of the working fluid higher than would be required if valves 136 were not present, thereby adversely affecting the efficiency with which working fluid stream 106 can be generated. It is generally desirable for the safety measures to be implemented without such adverse effects.

[0052] 3 is a simplified diagram of an example of a test station 102, according to an embodiment of the present disclosure. As described above, the test station 102 includes a test station controller 130, and at least one hydraulic actuator 104 and its corresponding control valve 132. Although only a single pair of hydraulic actuators 104 and control valves 132 is shown in FIG. 3 for ease of illustration, it will be understood that the test station 102 may include two or more actuators 104 and corresponding control valves 132, as shown in FIG. 2.

[0053] A control valve 132 for each hydraulic actuator 104 operates to control the flow rate (e.g., gallons per minute) of actuating fluid flow 106 to the actuator 104 received from a high pressure source (e.g., HPU 110) 137 and the discharge of flow 106' to a low pressure reservoir 138 (e.g., back to the reservoir of HPU 110). Additionally, the control valve 132 controls the direction of flow through the hydraulic actuator 104 to control the actuation applied to the test subject 130.

[0054] In one example, the hydraulic actuator 104 includes a cylinder 140 and an actuator rod 142 having a piston 144 housed within the cylinder 140. The cylinder 140 includes a first port 146 and a second port 148 through which a flow of actuating fluid 106 passes. The valve 132 controls the direction of the actuating fluid flow 106 through the first port 146 and the second port 148 to control the direction of movement of the actuator rod 142 and the speed at which the actuator rod 142 moves relative to the cylinder 140 based on the flow rate of the actuating fluid flow 106.

[0055] The control valve 132 may take any suitable form. Examples of the control valve 132 include a servo valve or a solenoid valve configured to provide variable flow and directional control as described above. As shown in FIG. 3, the control valve 103 generally includes electronics 150, a valve body 152, and a valve body actuator 154. The valve body 152 has an adjustable position that controls the direction and flow of the working fluid flow 106. The electronics 150 is configured to control the valve body actuator 154 to adjust the position of the valve body 152 in response to an actuator command signal 156. For example, the valve body 152 may take the form of a spool and the valve body actuator 154 may take the form of a servo. An example of this type of control valve 132 is described in U.S. Patent Application Publication No. 2016 / 0123355.

[0056] In some embodiments, the control valve 132 includes a position sensor 158 configured to detect a position of the valve body 152, for example relative to a housing 160 of the valve 132. The electronics 150 is configured to output a position signal 162 indicative of the detected position of the valve body 152.

[0057] During execution of a test program, the test station controller 130 generates a reference signal 164 related to a desired actuation to be performed by the hydraulic actuators 104 on the test object 103. Each actuator 104 includes an actuation sensor 166 configured to sense a parameter, e.g., displacement and / or force, of the actuation performed by the actuator 104 and generate a feedback signal 168 indicative of the sensed parameter. The actuation sensor 166 may include, for example, a displacement sensor 166A, such as a linear variable differential transformer configured to detect the displacement and / or movement of the actuator rod 142 relative to the cylinder 140 and generate a feedback signal 168A indicative of the detected displacement and / or movement, as shown in FIG. 3, and / or a load cell 166B, for example, configured to detect a force applied by the actuator 104 on the test object 103 and generate a feedback signal 168B indicative of the detected force. Conventional conditioning circuitry may be used to process (e.g., amplify, filter, etc.) the signals 168A and / or 168B to generate the final feedback signal 168.

[0058] The actuator controller 170 is configured to compare the reference signal 164 and the feedback signal 168 corresponding to each actuator 104 and issue a differential signal 172 to the corresponding control valve 132. Although the actuator controller 170 is shown in FIG. 3 as receiving a single reference signal 164 and issuing a single differential signal 172 corresponding to the depicted actuator 104, the actuator controller 170 may be configured to receive multiple reference signals 164 and corresponding feedback signals 168 from the test station controller 130 for each hydraulic actuator 104 of the test station 102 and issue a differential signal 172 to control the corresponding valve 132. In a conventional test station 102, the differential signal 172 acts as the illustrated actuator command signal 156 to the control valve 132 that adjusts the flow rate and / or flow direction of the fluid flow 106 to produce the desired actuation.

[0059] An embodiment of the present disclosure includes a flow control circuit (FRCC) 180 for each valve 132 that receives the differential signal 172 from the actuator controller 170 and outputs the actuator command signal 156 to the control valve 132. Alternatively, a single flow control circuit may be adapted to receive multiple differential signals 172 corresponding to the multiple actuators 104 of the test station 102 and output the actuator command signal 156 to the corresponding control valve 132. For ease of explanation, the flow control circuit 180 will be described with respect to its operation with respect to a single hydraulic actuator 104 and a single valve 132.

[0060] In one example, flow control circuit 180 has a first state in which actuator command signal 156 takes the form of differential signal 172, such as by passing differential signal 172 as actuator command signal 156, and a second state in which actuator command signal 156 takes the form of an attenuated differential signal 182. Flow control circuit 180 can transition between the first and second states in response to a flow attenuation signal 184, which can be generated by test station controller 130, system controller 126, or another device in system 100, such as a user-activated switch.

[0061] The flow rate of actuating fluid flow 106 through control valve 152 corresponding to actuator command signal 156 in the form of attenuated differential signal 182 is lower than the flow rate of actuating fluid flow 106 corresponding to actuator command signal 156 in the form of differential signal 172. Thus, when flow control circuit 180 is in the first state, control valve 152 is essentially controlled in a conventional manner by differential signal 172.

[0062] When the flow control circuit 180 is in the second state, the control valve 132 is controlled to reduce the flow rate of the actuating fluid flow 106 and the speed of the actuation performed by the actuator 104 relative to that dictated by the differential signal 172. As a result, the flow control circuit 180 operates to limit the speed of the actuation performed by the actuator 104 without forcing an additional pressure drop along the path of the actuating fluid flow 106, as would be the case if, for example, adding another safety inlet valve 136 were to be added.

[0063] In some embodiments, the attenuated differential signal 182 indicates a flow rate corresponding to about 50%-95% attenuation (e.g., about 75%-90% attenuation) of the flow rate of the differential signal 172, such that the attenuated differential signal 182 controls the valve 132 to provide the flow 106 having a reduced non-zero flow rate. For example, when the differential signal 172 is configured to drive the valve body 152 to a position corresponding to a flow rate of 20 gallons per minute, the corresponding attenuated differential signal 182 can be configured to drive the valve body 152 to a position corresponding to a reduced non-zero flow rate, such as 2 gallons per minute (e.g., 90% attenuation). In one embodiment, the non-zero flow rate corresponding to the attenuated differential signal 182 is less than about 20% of the flow rate corresponding to the differential signal 172. In one embodiment, the attenuated differential signal 182 limits the maximum velocity of the actuator rod 142 relative to the cylinder 140 to less than 15 millimeters per second, such as less than 10 millimeters per second.

[0064] In one embodiment, the flow control circuit 180 can be configured to provide approximately 100% attenuation of the differential signal 172 when in the second state, such that the control valve 132 substantially stops the actuation fluid flow 106 (e.g., ±0.05 gallons / minute) and substantially stops actuation. Thus, when the flow control circuit 180 is in the second state and provides 100% attenuation of the differential signal 172, the attenuated differential signal 182 drives the valve body 152 to a position that stops the flow 106, thereby fixing the position of the actuator rod 142 in place relative to the cylinder 140.

[0065] The flow control circuit 180 may take any suitable form. Figure 4 is a simplified diagram of an example of a flow control circuit 180, according to an embodiment of the present disclosure. In some embodiments, the circuit 180 includes an attenuation circuit 186 configured to generate an attenuated differential signal 182. The circuit 180 may include switching circuitry 187 for selectively outputting either the differential signal 172 or the attenuated differential signal 182 as the actuator command signal 156 based on an attenuation control signal 184.

[0066] The switching circuitry 187 may take any suitable form, such as a conventional switching circuit. In one example, the switching circuitry 187 comprises a pair of switches 188A and 188B (or equivalent circuitry) operative to pass either the differential signal 172 or the attenuated differential signal 182 as the command signal 156. The attenuation control signal or signals 184 may include a signal 184A operative to enable or disable the switches 188A and 188B, such as by inverting the signal 184A to the switch 188B using an inverter 190. Thus, for example, one signal 184A (e.g., logic 1) may enable the switch 188A and disable the switch 188B, such that the differential signal 172 is output as the command signal 156, and another signal 184A (e.g., logic 0) may disable the switch 188A and enable the switch 188B, such that the attenuated differential signal 182 is output as the command signal 156 (dashed lines).

[0067] The actuator command signal 156, the differential signal 172, and the damped differential signal 182 can take a variety of forms. In one example, each signal can take the form of a sinusoidal signal, with the average value of the sinusoidal signal causing the driver 154 to adjust the position of the valve body 152 which controls the direction and rate of actuating fluid flow 106 through the control valve 132. The direction of the flow 106 as well as the direction of the actuator rod 142 is controlled by whether the average value is positive or negative, and the rate of flow 106 is controlled by the magnitude of the average value.

[0068] 5 is a simplified diagram of an example sinusoidal differential signal 172 having a positive average value 191 relative to a zero axis 192. For example, the positive average value 191 drives the position of the valve body 152 to a position where the working fluid flow 106 flows in a first direction, such as into port 146 and out of port 148 (FIG. 3), while the negative average value 191 drives the position of the valve body 152 to a position where the working fluid flow 106 flows in a second direction, such as out of port 146 and into port 148. The position of the valve body 152 is further adjusted based on a magnitude 193 of the average value 191 such that the flow 106 has a higher flow rate when the magnitude 193 is larger and a lower flow rate when the magnitude 193 is smaller.

[0069] The attenuation circuit 186 may use any suitable technique to provide the attenuated differential signal 182. One example of the attenuated differential signal 182 is shown in Figure 6. In some embodiments, as shown in Figure 4, the generated attenuated differential signal 182 may be based on an attenuation control signal 184B.

[0070] In one example, the damping circuit 186 outputs a predetermined damped differential signal 182A in response to the damping control signal 184, regardless of the differential signal 172. The predetermined damped differential signal 182A can have a predetermined average value 191' (either positive or negative) and a magnitude 193' that commands the valve body driver 154 to move the position of the valve body 152 to a predetermined position, thereby generating a working fluid flow 106 in a predetermined direction and flow rate. In some embodiments, the commanded flow rate of the flow 106 based on the signal 182A is non-zero, for example, to limit the speed of actuation responsive to the flow 106 to less than about 15 millimeters per second, as described above. In other embodiments, the flow rate of the flow 106 based on the signal 182A is substantially zero.

[0071] In another example, the attenuation circuit 186 outputs an attenuated differential signal 182B corresponding to a fixed attenuation of the differential signal 172. Thus, the attenuation circuit 186 uses conventional attenuation circuitry to receive the differential signal 172 and attenuate the differential signal 172 by a fixed percentage to form the attenuated differential signal 182B. Thus, the attenuated differential signal 182B substantially mirrors the differential signal 172 but has a smaller average value 191' and magnitude 193' as shown by the example signal 182 shown in FIG. 6. The fixed attenuation can be selected based on the size of the hydraulic actuator 104 to ensure that the flow rate of the flow 106 and the corresponding actuation speed do not exceed a desired maximum, as described above. The fixed percentage can correspond to a value within the ranges described above to generate a non-zero or substantially zero flow rate of the flow 106.

[0072] In another example, the attenuation circuit 186 outputs an attenuated differential signal 182C corresponding to a variable attenuation of the differential signal 172. Thus, the attenuation circuit 186 receives the differential signal 172 and uses conventional attenuation circuitry to attenuate the differential signal 172 by a variable percentage based on the attenuation control signal 184B to form the attenuated differential signal 182C, which may take the form of the example signal 182 shown in FIG. 6. Thus, the attenuated differential signal 182C substantially mirrors the differential signal 172, but has a smaller average value 191' and magnitude 193'. The variable percentage represented by the signal 184B can be selected based on the size of the hydraulic actuator 104, as described above, to ensure that the flow rate of the flow 106 and the corresponding actuation speed do not exceed a desired maximum value. The variable attenuation can correspond to values ​​within the ranges described above to generate a non-zero or substantially zero flow rate of the flow 106.

[0073] In yet another example, the attenuation circuit 186 outputs an attenuated differential signal 182D corresponding to a predetermined maximum flow rate of the flow 106. FIG. 7 is a simplified diagram of an example of an attenuated differential signal 182D, according to an embodiment of the present disclosure. Here, the attenuation circuit 186 uses conventional attenuation circuitry to receive the differential signal 172 and truncate the differential signal 172 at a predetermined magnitude 196 to form the signal 182D. As a result, the average value 191′ and magnitude 193′ of the signal 182D are reduced from the average value 191 and magnitude 193 of the differential signal 172. The predetermined magnitude 196 can be selected based on the size of the hydraulic actuator 104, as described above, to ensure that the flow rate of the flow 106 and the corresponding actuation speed do not exceed a desired maximum value. The predetermined magnitude 196 can correspond to an attenuation value within the ranges described above to generate a non-zero flow rate of the flow 106.

[0074] 8 is a flow chart illustrating a method of controlling a hydraulic actuator 104 of a test station 102 according to an embodiment of the present disclosure. The test station may be formed in accordance with one or more of the embodiments described above. Although the method is described with respect to a single hydraulic actuator 104 and its control valve 132, it will be understood that the method may be applied to multiple hydraulic actuators 104 of a test station 102, such as actuators 104A-104D of the test station shown in FIG.

[0075] The method is performed using at least one controller (e.g., system controller 126, test station controller 130, etc.) of system 100, e.g., based on execution of program instructions using one or more processors of the controller. This means that a single controller can be used to perform the steps of the method, or multiple controllers can be used to perform the steps of the method. When multiple controllers are used to perform the steps of the method, different controllers can be used to perform different steps of the method. Thus, as used herein, the reference "at least one controller" does not require that each of the controllers perform all steps of the method or to perform all steps of the method.

[0076] In the method 200, the actuation sensors 166 (e.g., displacement sensors 166A and / or load cells 166B) are used to generate a feedback signal 168 indicative of a parameter of actuation by the hydraulic actuator 104. This may occur during the execution of a test on the test object 103 as defined by a test program. As discussed above, the parameter may be a displacement, movement, or load corresponding to the actuation.

[0077] At 202 in the method, a reference signal 164 indicative of a desired actuation is generated using a test controller 130 based on a test program, and at 204, a differential signal 172 is generated using an actuator controller 170 based on the difference between the reference signal 164 and a feedback signal 168.

[0078] The flow control circuit 180 is set to a first state or a second state by a flow damping signal 184. The flow control circuit 180 sends the differential signal 172 as the actuator command signal 156 to the control valve 132 when the flow control circuit 180 is in the first state, as shown at 206 in method. The flow control circuit 180 sends the damped differential signal 182 as the actuator command signal 156 to the control valve 132 when the flow control circuit 180 is in the second state, as shown at 208 in method.

[0079] In method 210, the flow rate and direction of the working fluid flow 106 is controlled by the control valve 132 based on the actuator command signal 156. The flow rate corresponding to the attenuated differential signal 182 is less than the flow rate corresponding to the differential signal 172.

[0080] The degree of damping performed by the flow control circuit 180 may be in accordance with the embodiments described above, such that the damped differential signal 182 indicates a non-zero flow rate, e.g., less than about 20% of the flow rate indicated by the corresponding differential signal 172, or 100% damping, e.g., to fix the actuator rod 142 in place. The non-zero flow rate indicated by the damped differential signal 182 may limit the maximum speed at which the actuator rod 142 can move relative to the cylinder 140 to less than 15 millimeters per second, e.g., less than 10 millimeters per second.

[0081] The controllers of system 100, such as system controller 126, test station controller 130, actuator controller 170, valve electronics 150, etc., may take any suitable form to control the various functions described herein, such as that of example controller 220 shown in Figure 9. Controller 220 may include one or more processors 222 and memory 224. The one or more processors 222 are configured to perform the various functions described herein in response to execution of instructions contained in memory 224, such as, for example, a test program.

[0082] The one or more processors 222 may be components of one or more computer-based systems and may include one or more control circuits, a microprocessor-based engine control system, and / or one or more programmable hardware components, such as a field programmable gate array (FPGA). The memory 224 represents local and / or remote memory or computer-readable media. Such memory 224 may comprise any suitable patent-eligible computer-readable medium and does not include transitory waves or signals. Examples of memory 224 include conventional data storage devices, such as hard disks, CD-ROMs, optical storage devices, magnetic storage devices, and / or other suitable data storage devices. The controller 220 may include circuitry 226 used by the one or more processors 222 to receive input signals 228 (e.g., sensor signals), issue control signals 230 (e.g., signals 164, 172), and / or communicate data 232, for example, in response to the one or more processors 222 executing instructions stored in the memory 224.

[0083] Although embodiments of the present disclosure have been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present disclosure.

Claims

1. 1. A method of controlling a hydraulic actuator of a test station of a dynamic testing system, the test station comprising: a hydraulic actuator configured to drive an actuation of the test object using a flow of actuating fluid; A control valve; An actuation sensor; A test controller; An actuator controller; A flow control circuit; It is equipped with The method comprises: generating a feedback signal indicative of a parameter of the actuation using the actuation sensor; generating a reference signal indicative of a desired operation based on a test program using the test controller; generating a differential signal based on a difference between the reference signal and the feedback signal using the actuator controller; setting the flow control circuit to one of a first state and a second state based on a flow decay signal; sending an actuator command signal to the control valve using the flow control circuit; sending the differential signal as the actuator command signal to the control valve when the flow control circuit is in the first state; sending a damped differential signal as the actuator command signal to the control valve when the flow control circuit is in the second state; and controlling a flow rate and a direction of the working fluid flow based on the actuator command signals; Including, The method, wherein the flow rate corresponding to the attenuated differential signal is less than the flow rate corresponding to the differential signal.

2. 2. The method of claim 1 , wherein the flow rate corresponding to the attenuated differential signal is a non-zero flow rate, and in one embodiment the non-zero flow rate is less than about 20% of the flow rate corresponding to the differential signal, and in a further embodiment the non-zero flow rate limits movement of an actuator rod of the hydraulic actuator driving the actuation to less than about 15 millimeters per second.

3. The method of claim 1 , wherein the flow rate corresponding to the attenuated differential signal is substantially zero, substantially fixing a position of an actuator rod that drives the actuation.

4. The hydraulic actuator includes: A cylinder and an actuator rod having a piston housed within the cylinder; It is equipped with Movement of the piston and actuator rod relative to the cylinder drives the actuation; The control valve is A housing, an inlet port connected to a supply of high pressure working fluid; an outlet port connected to a low pressure return reservoir; a first port connected to a first working volume defined by an interior of the cylinder and the piston; a second port connected to a second working volume defined by an interior of the cylinder and the piston; and a housing including: a valve body contained within the housing, the valve body having a position for directing the working fluid flow received at the inlet port to one of the first port and the second port, or to a port other than the first port and the second port, and controlling a flow rate of the working fluid flow; a valve body actuator configured to adjust a position of the valve body based on the actuator command signal; The method according to any one of claims 1 to 3, comprising:

5. The valve body drive unit includes a servo or a solenoid. The method of claim 4 , wherein the valve body comprises a spool or a piston.

6. said actuation including movement of said test object; the actuation sensor includes a displacement sensor; The method of any one of claims 1 to 5, wherein the feedback signal is indicative of a displacement or movement of the test object.

7. the actuation comprises a force on the test object; the actuation sensor includes a load cell; The method of any one of claims 1 to 5, wherein the feedback signal is indicative of a force applied to the test object.

8. 8. The method of claim 1, further comprising generating the flow attenuated signal using the test controller and / or attenuating the differential signal to form the attenuated differential signal using the flow control circuit.

9. 1. A test station for a dynamic testing system, comprising: a hydraulic actuator configured to drive an actuation of the test object using a flow of actuating fluid; a control valve configured to control the flow rate and direction of the actuation fluid flow and the actuation in response to an actuator command signal; an actuation sensor configured to generate a feedback signal indicative of a parameter of the actuation; a test controller configured to generate a reference signal corresponding to a desired actuation based on a test program; an actuator controller configured to generate a differential signal based on a difference between the reference signal and the feedback signal; a flow control circuit having a first state in which the flow control circuit is configured to send the differential signal as the actuator command signal to the control valve, and a second state in which the flow control circuit is configured to send an attenuated differential signal as the actuator command signal to the control valve; It is equipped with the flow control circuit transitions from the first state to the second state in response to a flow decay signal; The flow rate corresponding to the attenuated differential signal is less than the flow rate corresponding to the differential signal.

10. 10. The test station of claim 9, wherein the flow rate corresponding to the attenuated differential signal is a non-zero flow rate, and in one embodiment the non-zero flow rate is less than about 20% of the flow rate corresponding to the differential signal, and in a further embodiment the non-zero flow rate limits movement of an actuator rod of the hydraulic actuator driving the actuation to less than about 15 millimeters per second.

11. 10. The test station of claim 9, wherein the flow rate corresponding to the attenuated differential signal is substantially zero, fixing a position of an actuator rod that drives the actuation.

12. The hydraulic actuator includes: A cylinder and an actuator rod having a piston housed within the cylinder; It is equipped with Movement of the piston and the actuator rod drives the actuation; The control valve is 1. A valve housing comprising: an inlet port connected to a supply of high pressure working fluid; an outlet port connected to a low pressure return reservoir; a first port connected to a first working volume defined by an interior of the cylinder and the piston; a second port connected to a second working volume defined by an interior of the cylinder and the piston; and a valve housing including: a valve body contained within the valve housing, the valve body having a position for directing the working fluid flow received at the inlet port to one of the first port and the second port, or to a port other than the first port and the second port, and controlling a flow rate of the working fluid flow; a valve body actuator configured to adjust a position of the valve body based on the actuator command signal; A test station according to any one of claims 9 to 11, comprising:

13. The valve body drive unit includes a servo or a solenoid. The test station of claim 12 , wherein the valve body comprises a spool or a piston.

14. said actuation including movement of said test object; the actuation sensor includes a displacement sensor; A test station according to any one of claims 9 to 13, wherein the feedback signal is indicative of a displacement or movement of the test object.

15. the actuation comprises a force on the test object; the actuation sensor includes a load cell; A test station according to any one of claims 9 to 13, wherein the feedback signal is indicative of a force applied to the test object.

Images