Miniaturized hydraulic valve and application thereof in robot system

Abstract

An electro-hydraulic valve includes a valve housing having a common chamber and a metering port in communication with the common chamber. The valve housing is coupled to a valve manifold having an inlet port and an outlet port. A first nozzle in fluid communication with the inlet port has a first orifice. A second nozzle in fluid communication with the outlet port has a second orifice. A first valve disposed within the common chamber is operable to move the first valve between a closed position in which the first valve closes the first orifice and an open position in which the first valve opens the first orifice. A second valve disposed within the common chamber is operable to move the second valve between a closed position in which the second valve closes the second orifice and an open position in which the second valve opens the second orifice.

Description

[0001] Cross - reference to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 428,997, filed on November 30, 2022, the content of which is incorporated herein by reference.

[0003] Field

[0004] The present system, apparatus, and method generally relate to hydraulic valves, and more particularly to miniaturized hydraulic valves for hydraulically actuated robotic components.

[0005] Background

[0006] A robot is a machine that can assist or replace humans. Robots can be used in a variety of applications, including construction, manufacturing, monitoring, exploration, learning, and entertainment. For example, robots can be used in hazardous or uninhabitable environments.

[0007] Some robots require user input and can be operated by humans. Other robots have a degree of autonomy and can operate, at least in some cases, without human intervention. Some autonomous robots are designed to mimic human behavior. Autonomous robots can be particularly useful in applications where the robot is required to work for long periods without operator intervention, navigate in its operating environment, and / or adapt to a changing environment.

[0008] Hydraulics is a technology that involves the mechanical properties and use of liquids, and it is based on the theoretical foundation provided by fluid mechanics. In fluid power applications, hydraulics can be used for the generation, control, transmission, and distribution of power. In robotic applications, hydraulic components can be used alone or in combination with electric motors and other power sources to distribute power to the components of a robot, such as actuators.

[0009] A hydraulic system can include one or more hydraulic valves. Hydraulic valves can control the flow of hydraulic fluid in a hydraulic system. Some hydraulic valves control the flow of hydraulic fluid by opening or closing the valve. Some hydraulic valves control the flow rate of hydraulic fluid by continuously regulating the flow. Hydraulic valves can be actuated, for example, by a handle, knob, or cam, or can be solenoid - operated or pilot - operated.

[0010] A direction control valve can pause and restart the flow of hydraulic fluid and / or change the direction of flow. An example of a direction control valve is a two - way directional control valve that includes two ports known as an inlet and an outlet.

[0011] A pressure control valve can regulate the pressure of hydraulic fluid in a hydraulic system, for example, by releasing excessive pressure.

[0012] A flow control valve can be used to improve the performance of a hydraulic system by regulating the flow rate of hydraulic fluid through the hydraulic system.

[0013] Overview

[0014] In a representative example, a miniaturized hydraulic valve can include: a valve body having an inlet and an outlet; a fluid path through the valve body that hydraulically couples the inlet to the outlet, the fluid path including a nozzle with a diameter in a first range of 600 to 700 micrometers; a plunger positioned in the fluid path near the nozzle; and a piezoelectric material mechanically coupled to the plunger, the position of the plunger relative to the nozzle depending on at least one dimension of the piezoelectric material, the at least one dimension of the piezoelectric material responding to one or more electrical signals from an electrical system. When the electrical system does not supply power to the piezoelectric material during operation, the plunger is pushed against the nozzle to interrupt the flow of hydraulic fluid along the fluid path, the push being sufficient to interrupt the flow at a fluid pressure of at least 700 pounds per square inch (psi). When the electrical system supplies power to the piezoelectric material during operation, the plunger is displaced from the nozzle to form a gap between the plunger and the nozzle to allow hydraulic fluid to flow along the fluid path, the gap being proportional to the power supplied to the piezoelectric material, the plunger displacement being in a second range of 40 to 70 micrometers, the gap being sufficient to accommodate a flow rate of hydraulic fluid up to 0.5 liters per minute (lpm).

[0015] In another representative example, a hydraulic system can include a miniaturized hydraulic valve that includes: a valve body that includes an inlet and an outlet; a fluid path through the valve body that hydraulically communicatively couples the inlet to the outlet, the fluid path including a nozzle having a diameter in a first range of 600 microns to 700 microns; a plunger positioned in the fluid path proximate the nozzle; and a piezoelectric material mechanically communicatively coupled to the plunger. The hydraulic system can also include an electrical system electrically coupled to the piezoelectric material, at least one dimension of the piezoelectric material responsive to one or more electrical signals from the electrical system, and the position of the plunger relative to the nozzle depending on at least one dimension of the piezoelectric material. When the electrical system does not supply power to the piezoelectric material during operation, the plunger is urged against the nozzle to interrupt the flow of hydraulic fluid along the fluid path, the urging being sufficient to interrupt the flow at a fluid pressure of at least 700 pounds per square inch (psi). When the electrical system supplies power to the piezoelectric material during operation, the plunger is displaced from the nozzle to form a gap between the plunger and the nozzle to allow hydraulic fluid to flow along the fluid path, the gap being proportional to the power supplied to the piezoelectric material, the plunger displacement being in a second range of 40 microns to 70 microns, the gap being sufficient to accommodate a flow rate of hydraulic fluid up to 0.5 liters per minute (lpm).

[0016] In another representative example, a robotic arm can include a hydraulic control system physically coupled to a robotic body, a hydraulic actuation component physically coupled to the robotic body, and a hydraulic assembly, the hydraulic actuation component operable to cause movement of at least a portion of the robot, the hydraulic assembly including a miniaturized hydraulic valve that can include: a valve body that includes an inlet and an outlet; a fluid path through the valve body that hydraulically couples the inlet to the outlet, the fluid path including a nozzle having a diameter in a first range of 600 microns to 700 microns; a plunger positioned in the fluid path proximate the nozzle; and a piezoelectric material mechanically communicatively coupled to the plunger. The hydraulic assembly can also include an electrical system electrically coupled to the piezoelectric material, at least one dimension of the piezoelectric material responsive to one or more electrical signals from the electrical system, and the position of the plunger relative to the nozzle depending on at least one dimension of the piezoelectric material. When the electrical system does not supply power to the piezoelectric material during operation, the plunger is urged against the nozzle to interrupt the flow of hydraulic fluid along the fluid path, the urging being sufficient to interrupt the flow at a fluid pressure of at least 700 pounds per square inch (psi). When the electrical system supplies power to the piezoelectric material during operation, the plunger is displaced from the nozzle to form a gap between the plunger and the nozzle to allow hydraulic fluid to flow along the fluid path, the gap being proportional to the power supplied to the piezoelectric material, the plunger displacement being in a second range of 40 microns to 70 microns, the gap being sufficient to accommodate a flow rate of hydraulic fluid up to 0.5 liters per minute (lpm).

[0017] In another representative example, a robot may include a robot body, a hydraulic control system physically coupled to the robot body, a hydraulic actuating component physically coupled to the robot body, and a hydraulic assembly. The hydraulic actuating component is operable to cause movement of at least a portion of the robot. The hydraulic assembly includes a miniaturized hydraulic valve, and the miniaturized hydraulic valve may include: a valve body including an inlet and an outlet; a fluid path through the valve body that hydraulically couples the inlet to the outlet, the fluid path including a nozzle having a diameter in a first range of 600 microns to 700 microns; a plunger positioned in the fluid path proximate to the nozzle; and a piezoelectric material mechanically coupled to the plunger. The hydraulic assembly may further include an electrical system electrically coupled to the piezoelectric material. At least one dimension of the piezoelectric material responds to one or more electrical signals from the electrical system, and the position of the plunger relative to the nozzle depends on at least one dimension of the piezoelectric material. When the electrical system does not supply power to the piezoelectric material during operation, the plunger is pushed against the nozzle to interrupt the flow of hydraulic fluid along the fluid path, and the push is sufficient to interrupt the flow at a fluid pressure of at least 700 pounds per square inch (psi). When the electrical system supplies power to the piezoelectric material during operation, the plunger is displaced from the nozzle to form a gap between the plunger and the nozzle to allow the hydraulic fluid to flow along the fluid path, the gap being proportional to the power supplied to the piezoelectric material, the plunger displacement being in a second range of 40 microns to 70 microns, and the gap being sufficient to accommodate a flow rate of hydraulic fluid up to 0.5 liters per minute (LPM).

[0018] In another representative example, an electrohydraulic valve includes: a valve manifold having an inlet port and an outlet port; a valve housing having a common chamber defined therein, a metering port in communication with the common chamber, and a first end coupled to the valve manifold; a first nozzle in fluid communication with the inlet port, the first nozzle having a first nozzle tip portion disposed within the common chamber, the first nozzle tip portion including a first orifice; a second nozzle in fluid communication with the outlet port, the second nozzle having a second nozzle tip portion disposed within the common chamber, the second nozzle tip portion including a second orifice; a first valve plug disposed within the common chamber and positioned in opposition to the first orifice; a first valve actuator coupled to the first valve plug and operable to move the first valve plug between a closed position and an open position, in the closed position, the first valve plug contacts the first nozzle tip portion and closes the first orifice, in the open position, the first valve plug is offset from the first nozzle tip portion and creates a first gap between the first valve plug and the first orifice for allowing fluid to flow from the first orifice through to the common chamber; a second valve plug disposed within the common chamber and positioned in opposition to the second orifice; and a second valve actuator coupled to the second valve plug and operable to move the second valve plug between a closed position and an open position, in the closed position, the second valve plug contacts the second nozzle tip portion and closes the second orifice, in the open position, the second valve plug is offset from the second nozzle tip portion and creates a second gap between the second valve plug and the second orifice for allowing fluid to flow from the common chamber through to the second orifice.

[0019] In another representative example, a method of operating a hydraulic actuator includes: applying an electric field to a first valve actuator disposed within a common chamber of a valve unit to axially displace a first valve plug disposed within the common chamber from a first orifice connected to an inlet port of a valve manifold and form a first communication path between the inlet port and the common chamber through the first orifice; conveying fluid from a fluid source connected to the inlet port to the common chamber through the first communication path; conveying fluid from the common chamber to the hydraulic actuator through a metering port of the valve unit; removing the electric field from the first valve actuator to bias the first valve plug against the first orifice and close the first communication path; applying an electric field to a second valve actuator disposed within the common chamber of the valve unit to axially displace a second valve plug disposed within the common chamber from a second orifice connected to an outlet port of the valve manifold and form a second communication path between the outlet port and the common chamber through the second orifice; and discharging fluid from the common chamber to a fluid return connected to the outlet port through the second communication path. Brief Description of the Drawings

[0021] The various elements and actions depicted in the drawings are provided for illustrative purposes to support the detailed description. Unless a particular context requires otherwise, the sizes, shapes, and relative positions of the elements and actions shown are not necessarily drawn to scale and are not necessarily intended to convey any information or limitations. In general, like reference numerals are used to identify like elements or actions.

[0022] Figure 1 is a perspective view of an exemplary embodiment of a direct piezoelectric hydraulic valve according to the present system, apparatus, and method.

[0023] Figure 2A is according to the present system, apparatus, and method Figure 1 of a cross-sectional view of a direct piezoelectric hydraulic valve.

[0024] Figure 2B is according to the present system, apparatus, and method Figure 1 of a cross-sectional view of a portion of a direct piezoelectric hydraulic valve.

[0025] Figure 3A is a cross-sectional view of a portion of another exemplary embodiment of a direct piezoelectric hydraulic valve according to the present system, apparatus, and method.

[0026] Figure 3B is according to the present system, apparatus, and method Figure 3A of a perspective view of a cross-sectional direct piezoelectric hydraulic valve.

[0027] Figure 4A is a cross-sectional view of an exemplary embodiment of an enlarged piezoelectric hydraulic valve according to the present system, apparatus, and method.

[0028] Figure 4B is according to the present system, apparatus, and method Figure 4A of a perspective view of a cross-sectional enlarged piezoelectric hydraulic valve.

[0029] Figure 5 is according to the present system, apparatus, and method Figure 4A and Figure 4B of a perspective view of an enlarged piezoelectric hydraulic valve.

[0030] Figure 6A is a cross-sectional view of another exemplary embodiment of an enlarged piezoelectric hydraulic valve according to the present system, apparatus, and method.

[0031] Figure 6B is according to the present system, apparatus, and method Figure 6A of a perspective view of a cross-sectional enlarged piezoelectric hydraulic valve.

[0032] Figure 7 is according to the present system, apparatus, and method Figure 6A and Figure 6BPerspective view of an amplified piezoelectric hydraulic valve.

[0033] Figure 8 Schematic diagram of an exemplary embodiment of a hydraulic-powered robot having a miniaturized hydraulic valve integrated with the arm of a robot, according to the present system, apparatus, and method.

[0034] Figure 9 A robot according to the present system, apparatus, and method (e.g., Figure 8 of the robot) of a schematic diagram of an exemplary embodiment of a portion of the hydraulic system in the forearm, wrist, and hand.

[0035] Figure 10 Screenshot of an exemplary CFD simulation showing the flow path in an exemplary embodiment of an amplified piezoelectric hydraulic valve (e.g., Figure 4A , Figure 4B and Figure 5 of the amplified piezoelectric hydraulic valve), according to the present system, apparatus, and method.

[0036] Figure 11 Is the same as Figure 10 Screenshot of an exemplary CFD simulation showing the static pressure adjacent to and above the nozzle of an amplified hydraulic valve (e.g., Figure 4A , Figure 4B and Figure 5 of the amplified piezoelectric hydraulic valve), according to the present system, apparatus, and method.

[0037] Figure 12A Perspective view of an electrohydraulic valve including one valve unit.

[0038] Figure 12B - Figure 12C Is Figure 12A Cross-sectional view of the electrohydraulic valve.

[0039] Figure 12D - Figure 12F Is Figure 12A Cross-sectional view of the electrohydraulic valve showing the valves in different positions in the valve unit.

[0040] Figure 12G Is Figure 12A Cross-sectional view of the electrohydraulic valve showing the electrical feedthrough and pressure transducer attached to the cap of the valve unit.

[0041] Figure 12H Is Figure 12A Cross-sectional view of the electrohydraulic valve showing the metering port formed in the cap of the valve unit.

[0042] Figure 13 Is using Figure 12AThe circuit diagram of a hydraulic system that uses an electro-hydraulic valve to operate a single-acting hydraulic cylinder.

[0043] Figure 14A is a perspective view of an electro-hydraulic valve that includes two valve units.

[0044] Figure 14B is Figure 14A the cross-sectional view of the electro-hydraulic valve.

[0045] Figure 14C is an electro-hydraulic valve that includes multiple Figure 14A perspective view of a valve pack of the electro-hydraulic valve.

[0046] Figure 15 is a circuit diagram of a hydraulic system that uses Figure 14A the electro-hydraulic valve to operate a double-acting hydraulic cylinder.

[0047] Detailed description

[0048] The following description sets forth specific details in order to provide an understanding of the various embodiments and examples of the systems, devices, and methods of the present invention. Those skilled in the art will understand that some of the specific details described herein may be omitted or modified in alternative embodiments and examples, and that the various embodiments and examples described herein may be combined with each other and / or with other methods, components, materials, etc. in order to produce additional embodiments and examples.

[0049] In some instances, well-known structures and / or processes associated with computer systems and data processing are not shown or provided in detail in order to avoid unnecessarily complicating or obscuring the description of the embodiments and examples.

[0050] Unless the specific context otherwise requires, throughout this specification and the appended claims, the term “comprise” and its variants (e.g., “comprises” and “comprising”) are used in an open, inclusive sense, to mean “including, but not limited to.”

[0051] Unless the context requires otherwise, throughout this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents. For example, references to "an embodiment" and "the embodiment" respectively include "embodiments" and "the embodiments," and references to "an implementation" and "the implementation" respectively include "implementations" and "the implementations." Also, unless the context clearly dictates otherwise, the term "or" is generally employed in its broadest sense to mean "and / or."

[0052] The title and abstract of this disclosure are provided for convenience only and are not intended to and should not be construed as limiting the scope or meaning of the inventive systems, devices, and methods.

[0053] The technologies described in this application include systems, devices, and methods for a hydraulically powered robot. In particular, this application describes a hydraulic valve suitable for use in a hydraulic system (e.g., a hydraulic system used in a hydraulically powered robot). The hydraulic valve can be a miniaturized hydraulic valve.

[0054] Generally, in some applications of a robotic system, particularly in a humanoid robot, it may be desirable for the end effector to have sufficient power and precision while being assembled in a specific form factor. It may also be desirable for the connectors (e.g., cables, hoses, wires, etc.) between the end effector and other components of the robotic system to be at least partially within the robot. External connectors can be unsightly and may increase the external size of the robot, making it more difficult for the robot to operate in a confined space. External connectors can also be a hazard and may cause damage to the robot or its environment, e.g., if the connector catches on an object in the robot's environment.

[0055] The technologies described in this application include a hydraulic valve for hydraulic applications, which include but are not limited to hydraulic systems that provide power in a robotic system. For example, the valve can be used in a hydraulic system that provides power to the end effector of a robotic system (e.g., the hand of a humanoid robot), where some or all of the hydraulic system is adapted and / or miniaturized to be at least partially assembled within the robot (e.g., within the robot arm).

[0056] In some embodiments, at least a portion of a hydraulic system (e.g., at least one hydraulic hose) is routed through a pivot joint (e.g., the shoulder, elbow, forearm, wrist, and / or joints of a robotic arm). The pivot joint can be an example of a confined space. For example, the confined space can be volumetrically restricted. The confined space may include moving components that may interfere with the hydraulic hose(s) in the space and / or the hydraulic hose(s) traversing the space, as well as other hydraulic fittings and components in or traversing the space. The confined space can have a volume and / or shape that can change during operation (e.g., when the robot is in motion or performing a task). Generally in a confined space, and where the confined space is, for example, a pivot joint, it may be advantageous for the hydraulic fittings to be more compact. It may also be advantageous for the hydraulic hose and fittings (e.g., hydraulic valves) to have a smaller size in the confined space.

[0057] The techniques described in this application include miniaturized hydraulic valves for a hydraulic system. In some embodiments, the hydraulic system is used to control the actuation of various degrees of freedom (DOF) of a robotic hand of a robot. As described above, it may be desirable to miniaturize components of the hydraulic system (e.g., hydraulic valves) such that at least some components can be assembled within the internal volume of the robot and external hydraulic hoses can be eliminated or at least reduced.

[0058] The techniques described in this application include novel embodiments of a miniaturized piezoelectric lift valve. The lift valve can be used to control the timing and amount of hydraulic fluid flowing to a hydraulic device in a hydraulic system. The lift valve generally includes a) a nozzle having an aperture, and b) a plunger that is pressed against the nozzle (or pressed into the aperture) to close the valve and stop or at least reduce the flow of hydraulic fluid through the valve. Conventionally, a spring and / or solenoid is used to accomplish closing the valve. Conventionally, opening the valve is achieved by compressing the spring or solenoid to push or pull the plunger away from the aperture to allow fluid to flow through the nozzle.

[0059] This technique includes replacing the spring and / or solenoid with a piezoelectric material and using electro - controlled activation (expansion or contraction) of the piezoelectric material to open the aperture.

[0060] The performance of a hydraulic valve can vary with the viscosity of the hydraulic fluid flowing through the hydraulic valve. In some embodiments, the hydraulic fluid is oil. In some embodiments, the viscosity of peanut oil is in the range of 60 centistokes to 80 centistokes.

[0061] In operation, a higher fluid pressure in the hydraulic fluid of a hydraulic system can provide a greater force to an end effector of a robotic system (e.g., a robotic hand of a humanoid robot). In some embodiments, it may be desirable for the fluid pressure in the hydraulic system to be at least 700 pounds per square inch (psi). In one embodiment, the fluid pressure is 800 psi. The higher fluid pressure causes greater strain on the components of the hydraulic system (e.g., hydraulic valves). The present technology can accommodate fluid pressures that support embodiments in robotic systems.

[0062] In operation, the flow rate of the hydraulic fluid in a hydraulic system can at least partially determine the speed at which an end effector can move. A higher flow rate generally means a faster movement of the end effector. A higher flow rate may be more difficult to control. The present technology can accommodate flow rates of the fluid that support embodiments in robotic systems. In some embodiments, the fluid flow rate is less than 0.5 liters per minute (lpm). In one exemplary embodiment, the fluid flow rate is 0.2 lpm.

[0063] In some applications, it may be desirable for a hydraulic valve to operate efficiently at high pressure and low flow rate. For example, in some robotic systems, the fluid pressure in the hydraulic system of the robot is greater than 700 psi (pounds per square inch), and the flow rate of the hydraulic fluid in the hydraulic system of the robot is less than 0.4 lpm (liters per minute).

[0064] The miniaturized hydraulic valve described below is referred to in this application as a "high pressure, low flow rate" valve. The present technology combines operation at high fluid pressure (e.g., greater than 700 psi) with operation at low fluid flow rate (e.g., less than 0.5 lpm).

[0065] In some embodiments, there are approximately forty hydraulic valves located in the internal volume of each robotic arm. In some embodiments of the prior art, the size of the hydraulic valve is approximately 2 cm × 2 cm × 2 cm, which makes it challenging to assemble forty hydraulic valves in the internal volume of each robotic arm. In some embodiments of the present technology, the hydraulic valve is approximately 1 cm × 1 cm × 1 cm, and the hydraulic valves are arranged in a 2 cm × 2 cm × 10 cm rectangular block inside the forearm of each robotic arm.

[0066] It may be desirable for the hydraulic valve to consume less power than the prior art. It may also be desirable for the hydraulic valve to operate more cycles than the prior art. It may further be desirable for the hydraulic valve to consume no power in the closed state.

[0067] When an object or shape has an appearance or characteristics similar to that of a human, it is defined as humanoid. For example, a humanoid robot is a robot that has an appearance or characteristics similar to that of a human. A humanoid robot can be "humanoid" as a whole, or can have humanoid components (e.g., a torso, head, arms, and hands) attached to non-humanoid components (e.g., a wheeled base). Although the following description mainly focuses on hydraulically powered humanoid robots, those skilled in the art will understand that the hydraulic systems according to the present technology can be used to control hands, feet, tails, heads, or any applicable end effectors or actuators in humanoid or non-humanoid robots.

[0068] It may be advantageous to use hydraulics to drive a robotic arm and / or end effector for the following reasons:

[0069] Hydraulics can provide high speed and high strength within a humanoid envelope of a certain shape and size.

[0070] To accommodate humanoid envelope constraints, components (e.g., motors) can be located outside the envelope, or at least outside regions where the volume is constrained, and hydraulically coupled to components inside the envelope. Components are said to be hydraulically coupled if they are connected by a hydraulic fluid.

[0071] Hydraulics can provide high power density, especially when the motors are outside the constrained volume.

[0072] Hydraulics can at least reduce motion hysteresis. Hysteresis can manifest as twitchiness in the movement of the robot. Since the hydraulic fluid can be substantially incompressible, little or no potential energy is released when the static coefficient of friction is exceeded.

[0073] Hydraulics can provide concentrated power, thus applying all the power to a single degree of freedom (DOF).

[0074] Hydraulics can provide high-fidelity control of the robot, i.e., high-precision movement of the robot.

[0075] A hydraulic system includes hydraulic hoses for providing hydraulic coupling and hydraulic fittings for fixing the hydraulic hoses to other hydraulic components (e.g., pumps, valves, and actuator pistons).

[0076] Figure 1 is a perspective view of an exemplary embodiment of a hydraulic system 100 including a direct piezoelectric hydraulic valve 102 according to the present system, apparatus, and method. The hydraulic valve 102 includes a valve body 104. The valve body 104 includes three sections - an upper body 106, a central body 108, and a lower body 110.

[0077] The upper body 106 includes openings 112 and 114, fittings 116 and 118, and electrical pins 120 and 122. The electrical pins 120 and 122 provide an electrical communication link between the piezoelectric hydraulic valve 102 and the electrical system 124 via wires 126 and 128. As described below with reference to Figure 2A and Figure 2B The electrical system 124 is operable to provide an electrical signal to control the expansion of the piezoelectric material in the piezoelectric hydraulic valve 102. The electrical system 124 may include a controller.

[0078] The lower body 110 includes a port 130. The port 130 may be an inlet or an outlet. In some embodiments, the valve body 104 includes a manifold ( Figure 1 not shown), which has various additional ports that can be used as inlets, outlets, bleed lines, vents, electrical conduits, etc.

[0079] Figure 2A is of the present system, device, and method Figure 1 Cross-sectional view of the direct piezoelectric hydraulic valve 102. The direct piezoelectric hydraulic valve 102 includes a spring 202. The spring 202 is mechanically coupled to a T-fitting 204. The T-fitting 204 is mechanically coupled to the upper end of the piezoelectric sleeve 206. The T-fitting 204 covers the upper end of the piezoelectric sleeve 206 and extends downward through the internal volume of the piezoelectric sleeve 206. In operation, the spring 202 is pushed against the upper surface of the T-fitting 204.

[0080] The piezoelectric sleeve 206 includes a length of tubular piezoelectric material. The piezoelectric sleeve 206 may include lead zirconate titanate (PZT), for example, in a stack of one or more PZTs. The piezoelectric sleeve 206 is housed in a hollow cylinder 208. The piezoelectric sleeve 206 extends from the T-fitting 204 to the plunger 210, and the T-fitting 204 is mechanically coupled to the plunger 210 via the piezoelectric sleeve 206. The plunger 210 includes a washer 212.

[0081] The nozzle 214 is hydraulically coupled to the port 130. In some embodiments, the nozzle 214 has a diameter in the range of 600 micrometers (μm) to 700 μm.

[0082] The following refers to Figure 2B Describe the portion 216 of the direct piezoelectric hydraulic valve 102.

[0083] Figure 2B is of the present system, device, and method Figure 1 Cross-sectional view of the portion 216 of the direct piezoelectric hydraulic valve 102. The portion 216 is atFigure 2A In the identification. Portion 216 includes a central body 108, a lower body 110, a port 130, a lower end portion of the piezoelectric sleeve 206, a plunger 210, and a washer 212.

[0084] Reference Figure 1 、 Figure 2A and Figure 2B and, hydraulic fluid enters through port 130 in the lower body 110 of the hydraulic valve 102. The hydraulic fluid travels upward through the nozzle 214 toward the washer 212. The nozzle 214 includes a narrow channel extending along the longitudinal axis of the lower body 110.

[0085] The washer 212 is held in place by the plunger 210. In some embodiments, the washer 212 includes a polytetrafluoroethylene (PTFE) material. As described above, the plunger 210 is mechanically coupled to the piezoelectric sleeve 206. The piezoelectric sleeve 206 is pushed toward the nozzle 214 by the spring 202 and the T-shaped fitting 204 at the upper end of the piezoelectric sleeve 206.

[0086] An electrical system ( Figure 2A and Figure 2B not shown in) can be communicatively coupled to the piezoelectric sleeve 216. At least one dimension of the piezoelectric sleeve 216 can respond to one or more electrical signals from the electrical system. For example, the length of the piezoelectric sleeve 206 along the longitudinal axis of the hydraulic valve 102 can respond to an electrical signal from the electrical system. For example, the electrical signal can cause the length of the piezoelectric sleeve 206 to increase (i.e., to cause the piezoelectric sleeve 206 to expand). The position of the plunger 210 relative to the nozzle 214 can depend on this at least one dimension of the piezoelectric sleeve 206, e.g., the length of the piezoelectric sleeve 206.

[0087] In operation, when no electric field (E-field) is applied to the piezoelectric sleeve 206, the spring 202 pushes the piezoelectric sleeve 206 against the plunger 210 to hold the washer 212 against the upper opening of the nozzle 214. In this state, the direct piezoelectric hydraulic valve 102 is closed.

[0088] When an E-field is applied to the piezoelectric sleeve 206, the piezoelectric sleeve 206 expands longitudinally and pushes the T-shaped fitting 204 against the spring 202, causing the washer 212 to be pulled upward and away from the upper opening of the nozzle 214. In this case, the direct piezoelectric hydraulic valve 102 opens and hydraulic fluid can flow through the nozzle 214. The hydraulic fluid can flow into the volume around the washer 212 and can leave the direct piezoelectric hydraulic valve 102 via an outlet port ( Figure 2B not shown in).

[0089] In some embodiments, the hydraulic fluid flowing from port 130 (the inlet) of the direct piezoelectric hydraulic valve 102 to the outlet port is oil, such as peanut oil or mineral oil.

[0090] A hydraulic hose ( Figure 1 not shown) can be attached at port 130 using a suitable hydraulic fitting. Similarly, another hydraulic hose (also not shown Figure 1 ) can be attached at the outlet port of the direct piezoelectric hydraulic valve 102. The outlet port will be described and explained below with reference to Figure 3A and Figure 3B the direct piezoelectric hydraulic valve 300.

[0091] The length of the piezoelectric hydraulic valve 102 can be driven at least in part by the desired flow rate at the nozzle 214. In one embodiment, the piezoelectric hydraulic valve 102 described with reference to Figure 1 , Figure 2A and Figure 2B is approximately 6 cm long. In an example embodiment with a desired flow rate of 0.2 lpm, the washer 212 can move within the range of 40 micrometers (μm) to 70 μm. Generally, it is desirable for the pressure exerted by the spring 202 on the washer 212 to match the hydraulic fluid pressure in the piezoelectric valve 102 through appropriate longitudinal expansion of the piezoelectric sleeve 206. In one embodiment, the hydraulic fluid pressure in the piezoelectric valve 102 is approximately 800 psi, and the appropriate longitudinal expansion of the piezoelectric sleeve 206 is achieved by making the length of the piezoelectric sleeve 206 40 mm.

[0092] In some applications, it may be desirable for the length of the piezoelectric hydraulic valve to be less than 6 cm. An example application where further miniaturization is beneficial is an application where a large number of piezoelectric hydraulic valves (e.g., 40 piezoelectric hydraulic valves) are located within a confined space (e.g., the forearm of a hydraulically powered humanoid robot).

[0093] Figure 3A is a cross-sectional view that is part of another example embodiment of the direct piezoelectric hydraulic valve 300 according to the present system, device, and method. The direct piezoelectric hydraulic valve 300 includes a central body 302, a lower body 304, a piezoelectric sleeve 306 located within the inner cylindrical volume 308 of the central body 302, a plunger 310, a washer 312, a nozzle 314, an inlet 316, and an outlet 318.

[0094] In operation, when the direct piezoelectric hydraulic valve 300 is open, hydraulic fluid can flow from the inlet 316 through the direct piezoelectric hydraulic valve 300 to the outlet 318 in the directions indicated by arrows A, B, C, D, and F.

[0095] Figure 3B is according to the present system, device, and method Figure 3APerspective view of a cross-section of a direct piezoelectric hydraulic valve 300.

[0096] Figure 4A is a cross-sectional view of an exemplary embodiment of an amplified piezoelectric hydraulic valve 400 according to the present system, apparatus, and method. The amplified piezoelectric hydraulic valve 400 is more compact than the Figure 1 and Figure 2A direct piezoelectric hydraulic valve 102.

[0097] The amplified piezoelectric hydraulic valve 400 includes an upper body 402, a central body 404, and a lower body 406. In some embodiments, the valve body 402 comprises or is made of aluminum. The upper body 402 includes a central port 408 and two side ports 410a and 410b.

[0098] The central body 404 includes a housing 412 that encloses a chamber 414. The chamber 414 contains a piezoelectric block 416. The piezoelectric block 416 is mechanically coupled to a plunger 418. The plunger 418 includes a washer 420. In the amplified piezoelectric hydraulic valve 400, Figure 1 、 Figure 2A and Figure 2B the piezoelectric sleeve 206 of the direct piezoelectric hydraulic valve 102 is replaced by the piezoelectric block 416. An electric field (E-field) applied to the piezoelectric block 416 can cause the piezoelectric block 416 to contract in size. The contraction of the piezoelectric block 416 is at least partially amplified because the piezoelectric block 416 is an ellipsoid.

[0099] The lower body 406 includes a nozzle 422. In some embodiments, the nozzle 422 has a diameter in the range of 600 micrometers (μm) to 700 μm. In operation, when the amplified piezoelectric hydraulic valve 400 is closed, the piezoelectric block 416 pushes the plunger 418 and the washer 420 against the nozzle 422 to stop or at least reduce the flow of hydraulic fluid through the amplified piezoelectric hydraulic valve 400.

[0100] An electrical system ( Figure 4A not shown in

[0101] ) can be communicatively coupled to the piezoelectric block 416. At least one dimension of the piezoelectric block 416 can respond to one or more electrical signals from the electrical system. The position of the plunger 418 relative to the nozzle 422 can depend on at least one dimension of the piezoelectric block 416. For example, when the piezoelectric block 416 is an ellipsoid, the minor axis of the ellipsoid can respond to an electrical signal from the electrical system.

[0102] When an E-field is applied to the piezoelectric block 416, the piezoelectric block 416 contracts sufficiently to open the amplified piezoelectric hydraulic valve 400 and allow hydraulic fluid to flow through the amplified piezoelectric hydraulic valve 400.

[0103] In some embodiments, the contraction of the piezoelectric block 416 is sufficient to create a gap in the range of 40 μm to 70 μm between the washer 420 and the nozzle 422. In these embodiments, the flow rate of the hydraulic fluid through the amplified piezoelectric hydraulic valve 400 can be about 0.2 lpm, and the physical size of the amplified piezoelectric hydraulic valve 400 can be about 1 cm × 1 cm × 1 cm.

[0104] In some embodiments, the gap between the washer 420 and the nozzle 422 is proportional to the electrical power of the E-field applied to the piezoelectric block 416. The proportionality of the amplified piezoelectric hydraulic valve 400 is one of its advantages. In operation, the amplified piezoelectric hydraulic valve 400 is capable of adjusting the flow rate of the hydraulic fluid through the amplified piezoelectric hydraulic valve 400 to a value within the range of zero to a predetermined upper limit with very high resolution. The predetermined upper limit can be less than the design limit of the piezoelectric hydraulic valve 400.

[0105] In an exemplary embodiment, the resolution is 0.00006 of this range. In the same exemplary embodiment, when the predetermined upper limit of the flow rate of the hydraulic fluid through the amplified piezoelectric hydraulic valve 400 is 0.4 lpm, the amplified piezoelectric hydraulic valve 400 is capable of adjusting the flow rate of the hydraulic fluid through the amplified piezoelectric hydraulic valve 400 in increments of 0.000024 lpm.

[0106] The lower body 406 also includes an inlet 424, an inlet chamber 426, and an outlet chamber 428. In operation, when the amplified piezoelectric hydraulic valve 400 is open, the hydraulic fluid can flow from the inlet 424 through the amplified piezoelectric hydraulic valve 400 to the outlet chamber 428 in the directions indicated by arrows A, B, C, D, E, and F.

[0107] Figure 4B is according to the present system, apparatus, and method Figure 4A Perspective view of a cross-section of the amplified piezoelectric hydraulic valve 400. The amplified piezoelectric hydraulic valve 400 includes an outlet 430 fluidly coupled to the outlet chamber 428.

[0108] Figure 5 is according to the present system, apparatus, and method Figure 4A and Figure 4B Perspective view of a cross-section of the amplified piezoelectric hydraulic valve 400.

[0109] Figure 6A Cross-sectional view of another exemplary embodiment of the amplified piezoelectric hydraulic valve 600 according to the present system, apparatus, and method. The amplified piezoelectric hydraulic valve 600 is Figure 4A 、 Figure 4B andFigure 5 Variant of the amplified piezoelectric hydraulic valve 400. The amplified piezoelectric hydraulic valve 600 is more miniaturized than Figure 4A , Figure 4B and Figure 5 the amplified piezoelectric hydraulic valve 400.

[0110] The amplified piezoelectric hydraulic valve 600 includes an upper body 602, a central body 604, and a lower body 606. In some embodiments, the valve body 602 includes or is made of aluminum. The upper body 602 includes a central port 608 and two side ports 610a and 610b.

[0111] The central body 604 includes a housing 612 that encloses a chamber 614. The chamber 614 contains a piezoelectric block 616. The piezoelectric block 616 is mechanically coupled to a washer 618. An electric field (E-field) applied to the piezoelectric block 616 can cause the piezoelectric block to contract (i.e., decrease in size).

[0112] The lower body 606 includes a nozzle 620. In some embodiments, the nozzle 620 has a diameter in the range of 600 micrometers (μm) to 700 μm. In operation, when the amplified piezoelectric hydraulic valve 600 is closed, the piezoelectric block 616 pushes the washer 618 against the nozzle 620 to prevent or at least reduce the flow of hydraulic fluid through the amplified piezoelectric hydraulic valve 600. When an E-field is applied to the piezoelectric block 616, the piezoelectric block 616 contracts sufficiently to open the amplified piezoelectric hydraulic valve 600 and allow hydraulic fluid to flow through the amplified piezoelectric hydraulic valve 600.

[0113] In some embodiments, the contraction of the piezoelectric block 616 is sufficient to create a gap in the range of 40 μm to 70 μm between the washer 618 and the nozzle 620. In these embodiments, the flow rate of the hydraulic fluid through the amplified piezoelectric hydraulic valve 600 can be about 0.2 lpm, and the physical size of the amplified piezoelectric hydraulic valve 600 can be less than about 1 cm × 1 cm × 1 cm.

[0114] The lower body 606 also includes an inlet 622, an inlet chamber 624, and an outlet chamber 626. In operation, when the amplified piezoelectric hydraulic valve 600 is open, hydraulic fluid can flow from the inlet 622 through the amplified piezoelectric hydraulic valve 600 to the outlet chamber 626.

[0115] Figure 6B is according to the present system, device, and method Figure 6A Perspective view of a cross-section of the amplified piezoelectric hydraulic valve 600. The amplified piezoelectric hydraulic valve 600 includes an outlet 628 ( Figure 6A shown in Figure 7 ) fluidly coupled to the outlet chamber 626 (

[0116] Figure 7is according to the present system, apparatus, and method Figure 6A and Figure 6B A perspective view of a cross-sectionally enlarged piezoelectric hydraulic valve 600.

[0117] Figure 8 is a schematic diagram of an exemplary embodiment of a hydraulic-powered robot 800 having a hydraulic pump 802 integrated with an arm 804a of the robot 800. A hose is also referred to as a hydraulic hose in this application.

[0118] The robot 800 includes a base 806 and a humanoid upper body 808. The base 806 includes a pelvic region 810 and two legs 812a and 812b (collectively referred to as legs 812). Figure 8 Only an upper portion of the legs 812 is shown. In other exemplary embodiments, the base 806 may include a bracket and (optionally) one or more wheels.

[0119] The upper body 808 includes a torso 814, a head 816, a right arm 804a and a left arm 804b (collectively referred to as arms 804), and a right hand 818a and a left hand 818b (collectively referred to as hands 818). The arms 804 of the robot 800 are also referred to as robot arms in this application. The arms 804 of the robot 800 are humanoid arms. In other embodiments, the arms 804 have a form factor different from that of humanoid arms.

[0120] The hands 818 are also referred to as end effectors in this application. In other embodiments, the hands 818 have a form factor different from that of humanoid hands. Each hand 818 includes one or more finger-like members, such as finger 820 of hand 818a. The finger-like members may include fingers, thumbs, or similar structures of the hand or end effector.

[0121] In some embodiments, for example, the base 804 and / or the torso 814 of the upper body 808 houses a hydraulic control system. In some embodiments, alternatively, components of the hydraulic control system may be located outside the robot, for example, on a wheeled unit that rolls with the robot as it moves around, or in a fixed station to which the robot is tethered.

[0122] The hydraulic control system of the robot 800 includes a hydraulic pump 802 housed in the arm 804a, a reservoir 822, and an accumulator 824. A hose 826 provides a hydraulic connection between the accumulator 824 and a pressure valve 828 of the hydraulic control system. A hose 830 provides a hydraulic connection between a discharge valve 832 of the hydraulic control system and the reservoir 822.

[0123] The pressure valve 828 is hydraulically connected to the actuating piston 834 via a hose 836. The actuating piston 834 is hydraulically connected to the discharge valve 832 via a hose 838. Hoses 826 and 836 and the pressure valve 828 provide a forward path to the actuating piston 834. Hoses 830 and 838 and the discharge valve 832 provide a return path to the actuating piston 834. The pressure valve 828 and the discharge valve 832 can control the actuating piston 834 and can move the actuating piston 834, which can cause corresponding movement of at least a portion of the hand 818a (e.g., the finger 820).

[0124] In some embodiments, the pressure valve 828 and the discharge valve 832 are electrohydraulic servo valves controlled by a controller ( Figure 8 not shown in the figures). The electrohydraulic servo valve is also referred to in this application as a servo valve and a servo control valve. The controller can be implemented by any suitable combination of hardware, software, and / or firmware. The controller can include, for example, one or more application specific integrated circuits, standard integrated circuits, and / or computer programs executed by any number of computers, microcontrollers, and / or processors (including, for example, microprocessors, central processing units). In other embodiments, other suitable types of valves can be used.

[0125] In other embodiments, the hydraulic drive mechanism includes a motor and a drive piston. The drive piston can be linearly advanced by a lead screw, which can be coupled to the motor via a flexible shaft coupling. The drive piston can be hydraulically connected to a hose containing hydraulic fluid. The hose can extend from the drive piston to an actuating piston located elsewhere on the robot 800, e.g., in the hand 818a. When the drive piston is driven by the motor, the actuating piston can be forced to move, which can cause corresponding movement of at least a portion of the robot 800.

[0126] In some embodiments, Figure 8 the hydraulic fluid in the hydraulic hoses (including hoses 826, 830, 836, and 838) is oil, such as peanut oil or mineral oil.

[0127] Each hand 818 can have more than one degree of freedom (DOF). In some embodiments, each hand has up to eighteen (18) degrees of freedom. Each DOF can be driven by a corresponding actuating piston (e.g., the actuating piston 834). For clarity of illustration, only one actuating piston is shown in Figure 8 the figures. Each actuating piston can be located in the hand 818.

[0128] A single-action piston can use a spring to provide a return action for the piston. The DOF can be double-acting to achieve push-pull motion, meaning there are corresponding hoses connected to each side of the actuating piston. In one embodiment, there are two double-acting DOFs, and thus twenty (20) hoses extend to each hand 818 to control the eighteen (18) DOFs of each hand. In some embodiments, Figure 8 At least some of the hoses shown (e.g., hoses 826, 830, 836, and 838) belong to a hose bundle that can accommodate twenty (20) one-eighth inch (1 / 8 inch) hoses.

[0129] In some embodiments, a robot with an integrated hydraulic system (such as Figure 8 robot 800) may incorporate any or all of the teachings of U.S. Provisional Patent Application No. 63 / 191,732, filed on May 21, 2021, and titled "Systems, Devices, and Methods for A Hydraulic Robot Arm", which is hereby incorporated by reference in its entirety.

[0130] Although Figure 8 the example embodiments are of a hydraulically powered robot having only a single hydraulic system, those skilled in the art will understand that a hydraulically powered robot can include multiple hydraulic systems. In some embodiments, at least some of the multiple hydraulic systems are hydraulically isolated from each other. In some embodiments, at least some of the multiple hydraulic systems share a common hydraulic pump.

[0131] For a hydraulically powered robot, having multiple hydraulically isolated hydraulic systems can be beneficial. For example, a hydraulically powered robot can have multiple components or devices that include hydraulic actuators. A single hydraulic system operable to control the hydraulic actuators of multiple components or devices can be too large, too complex, or too expensive for a practical implementation. For example, it can be difficult to route hydraulic hoses from a single shared pump to multiple components or devices located in different areas of the robot (especially internally, as in robot 800). Hydraulic systems dedicated to a single component or device or to a subset of multiple components or devices can be more localized and more easily adapted to fit within a desired form factor.

[0132] Figure 1 , Figure 2A and Figure 2B the direct piezoelectric hydraulic valve 102, Figure 4A , Figure 4B and Figure 5The amplified piezoelectric hydraulic valve 400, and / or Figure 6A 、 Figure 6B and Figure 7 The amplified piezoelectric hydraulic valve 600 can be used in the hydraulic control system of the robot 800 to control the flow of hydraulic fluid in the hydraulic control system. Figure 1 、 Figure 2A and Figure 2B The direct piezoelectric hydraulic valve 102, Figure 4A 、 Figure 4B and Figure 5 The amplified piezoelectric hydraulic valve 400, and / or Figure 6A 、 Figure 6B and Figure 7 The amplified piezoelectric hydraulic valve 600 can be used, for example, in the pressure valve 828 and / or the discharge valve 832.

[0133] In some embodiments, the pressure valve 828 and the discharge valve 832 can be replaced by a single hydraulic valve having two channels. The two-channel hydraulic valve can be used to control the pressure and discharge flow into and out of the actuator piston.

[0134] Figure 1 、 Figure 2A and Figure 2B The direct piezoelectric hydraulic valve 102, Figure 4A 、 Figure 4B and Figure 5 The amplified piezoelectric hydraulic valve 400, and / or Figure 6A 、 Figure 6B and Figure 7 The amplified piezoelectric hydraulic valve 600 can be more compact than other types of hydraulic valves and can be advantageously deployed in confined spaces and / or in situations where a large number of hydraulic connections are to be made.

[0135] Figure 9 is a schematic diagram of an exemplary embodiment of a part 900 of the hydraulic system in the forearm 902, wrist 904, and hand 906 of a robot (e.g., Figure 8 the robot 800) according to the present system, device, and method. The hand 906 includes finger members 908.

[0136] The forearm 902 includes a set of valves 910 integrated with the forearm 902. The valves 910 include valve 910-1. (Only one valve is separately labeled for clarity.) The valves 910 can include pressure valves and discharge valves. The valves 910 can include electrohydraulic servo valves and can be operated by a controller ( Figure 9 not shown in

[0137] The finger members 908 include actuator pistons 912 integrated with the finger members 908. The actuator pistons 912 are hydraulically coupled to the valves 910 via pressure hoses 914 and discharge hoses 916.

[0138] The pressure hose 914 and the drain hose 916 pass through the wrist 904. The wrist 904 can be a confined space (as described above), and although the diameters of the hoses 914 and 916 may typically need to be large enough to meet the pressure / force requirements of part 900 of the hydraulic system, in the region of the wrist 904, the respective diameters of each of the hoses 914 and 916 are small enough and each of the hoses 914 and 916 is flexible enough to navigate the wrist 904, which can be advantageous.

[0139] Figure 1 、 Figure 2A and Figure 2B the direct piezoelectric hydraulic valve 102 of Figure 4A 、 Figure 4B and Figure 5 the amplified piezoelectric hydraulic valve 400 of Figure 6A 、 Figure 6B and Figure 7 the amplified piezoelectric hydraulic valve 600 of Figure 9 can be used in part 900 of a hydraulic control system of Figure 1 、 Figure 2A and Figure 2B the direct piezoelectric hydraulic valve 102 of Figure 4A 、 Figure 4B and Figure 5 the amplified piezoelectric hydraulic valve 400 of Figure 6A 、 Figure 6B and Figure 7 the amplified piezoelectric hydraulic valve 600 of Figure 1 、 Figure 2A and Figure 2B the direct piezoelectric hydraulic valve 102 of Figure 4A 、 Figure 4B and Figure 5 the amplified piezoelectric hydraulic valve 400 of Figure 6A 、 Figure 6B and Figure 7 the amplified piezoelectric hydraulic valve 600 of

[0140] such as Figure 9As shown, the forearm 902, wrist 904, and hand 906 can be restricted spaces, and there can be a large number of hydraulic connections to be made (e.g., to valve 910). In one embodiment, there are two double-acting DOFs, and thus twenty (20) hoses extend to the hand 906 to control the eighteen (18) DOFs of each hand. In some embodiments, there are twenty (20) one-eighth inch (1 / 8 inch) hoses to be accommodated in the forearm 902, wrist 904, and hand 906.

[0141] As described above, it may be desirable for a hydraulic valve to operate efficiently at high pressures and low flow rates. The miniaturized hydraulic valve described above is referred to herein as a "high pressure, low flow rate" valve. For example, the miniaturized hydraulic valve described in this application can combine operation at high fluid pressures (e.g., greater than about 700 psi) with operation at low fluid flow rates (e.g., less than about 0.5 lpm).

[0142] For example, in a robotic application, the fluid pressure and fluid flow rate in a hydraulic valve for operating elements of a robotic hand can be related to the desired performance of the robotic hand as well as the desired physical size and form factor of the hydraulic valve. One aspect of the present technology is that the nozzle size and stroke of a hydraulic valve can be determined at least in part based on the desired performance of the hydraulic valve as well as the desired physical size and form factor of the hydraulic valve. Determining the nozzle size and stroke of a hydraulic valve can include analysis and / or simulation, such as computational fluid dynamics (CFD) simulation.

[0143] Figure 10 is a screen shot 1000 of an example CFD simulation, which shows the flow path in an example embodiment of a magnified piezoelectric hydraulic valve (e.g., Figure 4A , Figure 4B and Figure 5 's magnified piezoelectric hydraulic valve 400) according to the present system, device, and method.

[0144] The screen shot 1000 includes an inlet 1002, an outlet 1004, and flow paths 1006 (e.g., flow paths 1006-1 and 1006-2). The screen shot 1000 shows the CFD simulation results for an example stroke of 40 μm of the magnified piezoelectric hydraulic valve. The CFD simulation results shown in the screen shot 1000 show that, for illustrative purposes, a desired upper limit of fluid flow rate can be achieved with an example stroke of 40 μm. Other embodiments of the present technology may have different strokes.

[0145] Figure 11 is the screen shot 1100 of the same example CFD simulation as Figure 10 which shows a magnified hydraulic valve (e.g., Figure 4A , Figure 4B andFigure 5 The static pressure of the nozzle of the amplified piezoelectric hydraulic valve 400) is adjacent to and above it.

[0146] Screenshot 1100 includes a nozzle 1102 having a channel 1104. Screenshot 1100 shows the static pressure at the upper end of the channel 1104 where the channel 1104 exits the nozzle 1102. Figure 11 The example CFD simulation results shown are for an amplified piezoelectric hydraulic valve, where, for illustrative purposes, there is a 40 μm gap between the upper end of the channel 1104 of the nozzle 1102 and the gasket (e.g., Figure 4A , Figure 4B and Figure 5 the gasket 420) of the amplified piezoelectric hydraulic valve 400.

[0147] The CFD simulation results shown in screenshot 1100 indicate that, for the example 40 μm stroke and example nozzle dimensions used in the CFD simulation, the desired fluid pressure can be achieved. Other embodiments of the present technology may use different strokes and / or nozzle dimensions.

[0148] Figure 12A - Figure 12C An exemplary electro - hydraulic valve 1200 including a valve unit 1201 is shown. The valve unit 1201 is disposed on a first side of a valve manifold 1202 having an inlet port 1218 and an outlet port 1220. The valve unit 1201 includes a common chamber 1208 that contains a first valve 1203 operable to open or close an inlet orifice 1210 and a second valve 1205 operable to open or close an outlet orifice 1214. The inlet orifice 1210 is fluidly connected to the inlet port 1218 of the valve manifold 1202, and the outlet orifice 1214 is fluidly connected to the outlet port 1220 of the valve manifold 1202. The valve unit 1201 includes a metering port 1222 fluidly connected to the common chamber 1208. The metering port 1222 may be connected to a hydraulic actuator (e.g., a single - acting hydraulic cylinder). The valve unit 1201 may include a pressure transducer 1225 to measure the pressure within the common chamber 1208.

[0149] Figure 13 is a simplified circuit diagram of an example hydraulic system 1300 including the electro - hydraulic valve 1200. The valve manifold inlet port 1218 (see Figure 12B - Figure 12C) can be fluidly connected to the accumulator 1302 through the main manifold 1318. The accumulator 1302 receives pressurized fluid (e.g., oil) from the pump 1304, which has a suction end fluidly connected to the reservoir 1314. The hydraulic fluid pumped from the pump 1304 to the accumulator 1302 can pass through the direction valve 1316, the high-pressure filter 1306, the check valve 1308, and the main manifold 1318. The hydraulic system 1300 can include a pressure relief valve 1310 fluidly connected to the reservoir 1314. When the hydraulic system 1300 is shut down, the pressure relief valve 1310 can relieve the pressure in the accumulator 1302. The valve unit metering port 1222 (see Figure 12B - Figure 12C ) can be connected to the hydraulic actuator 1312 via the hydraulic line 1320. The valve manifold outlet port 1220 can be fluidly connected to the reservoir 1314.

[0150] The hydraulic system 1300 can operate in various modes. In the first mode, the first valve 1203 is open while the second valve 1205 is closed. In this mode, the pressurized fluid from the accumulator 1302 can flow into the common chamber 1208 through the inlet port 1218 and through the inlet gap formed by the open first valve 1203. The pressurized fluid in the common chamber 1208 can be delivered to the hydraulic actuator 1312 through the metering port 1222 and the hydraulic line 1320. The flow rate of the hydraulic fluid flowing into the common chamber 1208 can be controlled based on the power requirements of the hydraulic actuator 1312. The pressure transducer 1225 can be used to determine the power applied at the hydraulic actuator 1312 based on the pressure measurement in the common chamber 1208. In the second mode, the first valve 1203 can be closed while the second valve 1205 is open. In this mode, the fluid in the common chamber 1208 can be discharged to the reservoir 1314 through the outlet gap formed by the open second valve 1205 and through the outlet port 1220. In the third mode, the first valve 1203 and the second valve 1205 can be open. In this mode, the fluid can circulate through the common chamber 1208, from the inlet port 1218, through the inlet gap formed by the open first valve 1203, through the outlet gap formed by the open second valve 1205, and to the outlet port 1220.

[0151] Reference Figure 12B and Figure 12C, the valve unit 1200 may include a valve housing 1231 having a valve body 1232 and a valve cover 1234. The valve cover 1234 may be attached to the first end of the valve body 1232 or integrally formed with the first end of the valve body 1232. The second end of the valve body 1232 may be positioned or mounted on the first side of a manifold block 1236 of the valve manifold 1202 such that the valve cover 1234 is in a relative relationship with the first side of the manifold block 1236. The valve housing 1231 may be fixed to the manifold block 1236 using any suitable method (e.g., using bolts 1238 that extend through holes in the valve cover 1234 and the valve body 1232 into holes in the manifold block 1236).

[0152] A common chamber 1208 is defined within the valve body 1232 and extends between the opposite valve cover 1234 and the first side of the manifold block 1236. One or more sealing members (or gaskets) 1240 may be disposed at the interface between the valve body 1232 and the valve cover 1234 to prevent leakage of the common chamber fluid through this interface. One or more sealing members (or gaskets) 1242 may be disposed at the interface between the manifold block 1236 and the valve body 1232 to prevent leakage of the common chamber fluid from this interface.

[0153] The manifold block 1236 includes an inlet port 1218 and an outlet port 1220 of the valve manifold 1202. The manifold block 1236 may include a first bore 1244 that extends into a first portion 1208a of the common chamber 1208 and is connected to the inlet port 1218. The manifold block 1236 may include a second bore 1246 that extends into a second portion 1208b of the common chamber 1208 and is connected to the outlet port 1220.

[0154] The manifold block 1236 includes the inlet port 1218. The manifold block 1236 may include a first bore 1244 that is connected to the inlet port 1218 and extends into a first portion 1208a of the common chamber 1208. The valve unit 1201 may include an inlet nozzle 1212 having a distal portion that includes an inlet orifice 1210. The inlet nozzle 1212 may be mounted in the first bore 1244, wherein the distal portion of the inlet nozzle 1212 includes the inlet orifice 1210 that extends into the chamber portion 1208a. One or more sealing members (or gaskets) 1248 may be disposed at the interface between the inlet nozzle 1212 and the wall of the first bore 1244 to prevent leakage of the common chamber fluid from this interface.

[0155] The manifold block 1236 includes an outlet port 1220. The manifold block may include a second hole 1246 that is connected to the outlet port 1220 and extends to a second portion 1208b of the common chamber 1208. The valve unit 1201 may include an outlet nozzle 1216 having a distal portion that includes an outlet orifice 1214. The outlet nozzle 1216 may be installed in the second hole 1246, wherein the distal portion of the outlet nozzle 1246 includes the outlet orifice 1214 that extends into the chamber portion 1208b. One or more sealing members (or gaskets) 1250 may be disposed at the junction between the outlet nozzle 1216 and the wall of the second hole 1246 to prevent leakage of the common chamber fluid from the junction.

[0156] The manifold block 1236 may include a third hole 1245 and a fourth hole 1247 that are respectively opposite to the first hole 1244 and the second hole 1246. When two valve units are disposed on opposite sides of the manifold block 1236 (see Figure 14B ), the third hole 1245 and the fourth hole 1247 may accommodate additional inlet nozzles and outlet nozzles. When the third hole 1245 and the fourth hole 1247 are not in use, end caps 1249 may be installed to close the third hole 1245 and the fourth hole 1247 and prevent fluid from gushing out of the valve manifold through the third hole 1245 and the fourth hole 1247.

[0157] The first valve 1203 disposed within the chamber portion 1208a includes a first valve plug 1204 (or first valve plunger) that is movable to close or open the inlet orifice 1210. When the inlet orifice 1210 is open, a fluid communication path is formed that extends from the inlet port 1218 through the inlet orifice 1210 to the common chamber 1208. The first valve 1203 includes a first valve actuator 1226 that is coupled to the first valve plug 1204 and is operable to move the first valve plug 1204 between a closed position and an open position.

[0158] The second valve 1205 disposed within the chamber portion 1208b includes a second valve plug 1206 that is movable to close or open the outlet orifice 1214. When the outlet orifice 1214 is open, a fluid communication path is formed that extends from the common chamber 1208 through the outlet orifice 1214 to the outlet port 1220. The second valve 1205 includes a second valve actuator 1228 that is coupled to the second valve plug 1206 and is operable to move the second valve plug 1206 between a closed position and an open position.

[0159] The first valve plug 1204 is disposed in the chamber portion 1208a in a relationship opposite to the inlet orifice 1210. The first valve plug 1204 may be axially aligned with the inlet nozzle 1212 (e.g., along the axial axis L1). The first valve plug 1204 may include a retainer 1252 and a gasket 1254 fitted within an opening of the retainer 1252. The retainer 1252 may be coupled to the first valve actuator 1226 (e.g., by a threaded pin 1256). The gasket 1254 is exposed at the distal end of the first valve plug 1204 and is positioned in a relationship opposite to the inlet orifice 1210. For example, the gasket 1254 may have a flat disc shape. The size (e.g., diameter) of the gasket 1254 is larger than the size of the inlet orifice 1210 such that when the first valve plug 1204 is biased against the end portion of the inlet nozzle 1212, the gasket 1254 can cover the inlet orifice 1210. In some examples, the inlet orifice 1210 may have a diameter in the range of 600 microns to 700 microns. The gasket 1254 may be made of a material (e.g., PTFE) that can form a seal against the end portion of the inlet nozzle 1212.

[0160] The second valve plug 1206 is disposed in the chamber portion 1208b in a relationship opposite to the outlet orifice 1214. The second valve plug 1206 may be axially aligned with the outlet nozzle 1216 (e.g., along the axial axis L2, and the axial axis L2 may be parallel to the axial axis L1). The second valve plug 1206 may include a retainer 1280 and a gasket 1282 fitted within an opening of the retainer 1280. The retainer 1280 may be coupled to the second valve actuator 1228 (e.g., by a threaded pin 1284). The gasket 1282 is exposed at the distal end of the second valve plug 1206 and is positioned in a relationship opposite to the outlet orifice 1214. For example, the gasket 1282 may have a flat disc shape. The size (e.g., diameter) of the gasket 1282 is larger than the diameter of the outlet orifice 1214 such that when the second valve plug 1206 is biased against the end portion of the outlet nozzle 1216, the gasket 1282 can cover the outlet orifice 1214. In some examples, the outlet orifice 1214 may have a diameter in the range of 600 microns to 900 microns. The gasket 1282 may be made of a material (e.g., PTFE) that can form a seal against the end portion of the outlet nozzle 1216.

[0161] In some examples, the first valve actuator 1226 may include a piezoelectric actuator 1258 (or more than one piezoelectric actuator) that axially deforms in response to an applied electric field (e.g., an applied voltage or current). The axial deformation of the piezoelectric actuator 1258 may be translated into axial movement of the first valve plug 1204 within the chamber portion 1208a. In one example, the piezoelectric actuator 1258 may be a magnified piezoelectric actuator that includes a piezoelectric element 1260 mounted within a flexure housing 1262. The first valve plug 1204 may be coupled (e.g., via a threaded pin 1256) to the flexure housing 1262. When an electric field is applied to the piezoelectric actuator 1258, the piezoelectric element 1260 elongates laterally (e.g., in a direction transverse to the axial axis L1), causing the flexure housing 1262 to shorten axially (e.g., in a direction parallel to the axial axis L1). The amount of shortening of the flexure housing 1262 is proportional to the applied electric field and determines the axial displacement of the first valve plug 1204 in a direction parallel to the axial axis L1.

[0162] In some examples, the second valve actuator 1228 may include one or more piezoelectric actuators. In the illustrated example, the second valve actuator 1228 includes two piezoelectric actuators 1288a, 1288b. Each piezoelectric actuator 1288a, 1288b may axially deform in response to an applied electric field (e.g., an applied voltage or current). The combined axial deformation of the piezoelectric actuators 1288a, 1288b may be translated into axial movement of the second valve plug 1206 within the chamber portion 1208b. In one example, each piezoelectric actuator 1288a, 1288b may be a magnified piezoelectric actuator that includes a piezoelectric element 1290a, 1290b mounted within respective flexure housings 1292a, 1292b. The flexure housings 1292a, 1292b may be coupled together (e.g., using a threaded pin 1294). The second valve plug 1206 may be coupled (e.g., using a threaded pin 1284) to the adjacent piezoelectric actuator 1288a.

[0163] When an electric field is applied to each of the piezoelectric actuators 1288a, 1288b, the respective piezoelectric actuators 1288a, 1288b elongate laterally (e.g., in a direction transverse to the axial axis L2), causing the respective flexure housings 1292a, 1292b to shorten axially (e.g., in a direction parallel to the axial axis L2). The amount of shortening of each flexure housing 1292a, 1292b is proportional to the electric field applied to the respective piezoelectric actuator 1288a, 1288b. The axial displacement of the second valve plug 1228 in a direction parallel to the axial axis L2 is determined by the combination of the amounts of axial shortening of the flexure housings 1292, 1292.

[0164] Compared with a single piezoelectric actuator, two piezoelectric actuators 1288a, 1288b can provide a higher stroke, which can help discharge fluid from the common chamber 1208 through the outlet orifice 1214 to the outlet port 1220. In some examples, the second valve actuator 1228 can have a single piezoelectric actuator configured to provide sufficient stroke to discharge fluid from the common chamber 1208 to the outlet port 1220. In some examples, a combination of a single piezoelectric actuator and a relatively large outlet orifice 1214 can be used to discharge fluid from the chamber 1208 to the outlet port 1220.

[0165] In some examples, the valve cover 1234 can include an electrical feedthrough 1229 (see Figure 12G and Figure 12H ) that extends into the common chamber 1208 and is connected to the valve actuators 1226, 1228. The electrical feedthrough 1229 can be used to supply power to the piezoelectric elements of the piezoelectric actuators 1258, 1288a, 1288b.

[0166] The first valve 1203 can have a closed position in which the first valve plug 1204 is biased against the end portion of the inlet nozzle 1212 and the inlet orifice 1210 is closed or sealed (e.g., the gasket 1254 covers the inlet orifice 1210). The first valve 1203 can have an open position (or a series of open positions) in which the first valve plug 1204 is lifted from the end portion of the inlet nozzle 1212 and the inlet orifice 1210 is opened (e.g., exposed to the common chamber 1208). When the first valve 1203 is in the open position, an inlet gap G1 (as Figure 12D shown) is formed between the first valve plug 1204 and the inlet orifice 1210. The size of the inlet gap G1 and the pressure of the fluid at the inlet port 1218 determine the rate at which the fluid can flow into the common chamber 1208 through the inlet orifice 1210. The closed position of the first valve 1203 can correspond to a state where no electric field is applied to the piezoelectric actuator 1258.

[0167] The second valve 1205 can have a closed position in which the second valve plug 1206 is biased against the end portion of the outlet nozzle 1216 and the outlet orifice 1214 is closed or sealed (e.g., the gasket 1282 covers the outlet orifice). The second valve 1205 can have an open position (or a series of open positions) in which the second valve plug 1206 is lifted from the end portion of the outlet nozzle 126 and the outlet orifice 1214 is opened (e.g., exposed to the common chamber 1208). When the second valve 1205 is in the open position, an outlet gap G2 is formed between the second valve plug 1206 and the outlet orifice 1214. The size of the outlet gap G2 and the pressure of the fluid in the common chamber 1208 determine the rate at which the fluid can flow through the outlet orifice 1214 to the outlet port 1220. The closed position of the second valve 1205 can correspond to a state in which no electric field is applied to either of the piezoelectric actuators 1288a, 1288b.

[0168] Reference Figure 12C , the first valve 1203 can include a stroke adjustment 1264 that can be used to adjust the position of the first valve plug 1204 after the valve unit 1201 is assembled to the valve manifold 1202. For example, the position of the first valve plug 1204 can be adjusted such that when no electric field is applied to the piezoelectric actuator 1258, the first valve plug 1204 contacts the end portion of the inlet nozzle 1212 to close the inlet orifice 1210.

[0169] The valve cover 1234 can include a first hole 1268 that can be axially aligned with a first hole 1244 in the manifold block 1236. The stroke adjustment 1264 can include an adjustment head 1266 received in the first hole 1268. The adjustment head 1266 is coupled to the piezoelectric actuator 1258 (e.g., the adjustment head 1266 can be coupled to the flexure housing 1262 of the piezoelectric actuator 1258 by a threaded pin 1270). A sealing member (or washer) 1272 can be disposed between the adjustment head 1266 and the wall of the first hole 1268 to prevent leakage of the chamber fluid through the path between the hole 1268 and the adjustment head 1266.

[0170] The stroke adjustment device 1264 may include an adjustment screw 1274 that extends through an opening 1276 in the valve cover 1234 into a first hole 1268 and further into a threaded opening 1278 in the adjustment head 1266. The adjustment screw 1274 is supported by supports 1277, 1279 for free rotation relative to the first hole 1268 and is axially restricted by a nut 1284 screwed onto the screw. When the adjustment screw 1274 rotates, the adjustment head 1266 may travel axially along the adjustment screw 1274 using the thread engagement between the threaded opening 1278 and the adjustment screw 1274. The adjustment screw 1274 may be rotated until stopped by contact between the first valve plug 1204 and the end portion of the inlet nozzle 1212.

[0171] The second valve 1205 may include a stroke adjustment device 1293 that can be used to adjust the position of the second valve plug 1206 after the valve unit 1201 is assembled onto the valve manifold 1202. For example, the position of the second valve plug 1206 may be adjusted such that when no electric field is applied to the piezoelectric actuators 1288a, 1288b, the second valve plug 1206 contacts the end portion of the outlet nozzle 1216 to close the outlet orifice 1214.

[0172] The valve cover 1234 may include a second hole 1294 that may be axially aligned with a second hole 1246 in the manifold block 1236. The stroke adjustment device 1293 may include an adjustment head 1295 received in the second hole 1293. The adjustment head 1295 is coupled to the piezoelectric actuator 1288b (e.g., the adjustment head 1295 may be coupled to the flexure housing 1292b using a threaded pin 1296). A seal member (or washer) 1297 may be disposed between the adjustment head 1295 and the wall of the second hole 1294 to prevent leakage of chamber fluid through the path between the hole 1292 and the adjustment head 1295.

[0173] The stroke adjustment device 1293 may include an adjustment screw 1298 that extends through an opening 1299 in the valve cover 1234 into the second hole 1294 and further into a threaded opening 1281 in the adjustment head 1295. The adjustment screw 1298 is supported by supports 1283, 1285 for free rotation relative to the second hole 1294 and is axially restricted by a nut 1287 screwed onto the screw. When the adjustment screw 1298 rotates, the adjustment head 1295 may travel axially along the adjustment screw 1298 using the thread engagement between the threaded opening 1281 and the adjustment screw 1298. The adjustment screw 1298 may be rotated until stopped by contact between the second valve plug 1206 and the end portion of the outlet nozzle 1216.

[0174] As Figure 12FAs shown, when the valve 1200 is initially assembled, the valve plugs 1204, 1206 can be offset (or axially displaced) from the respective end portions of the nozzles 1212, 1216 while no electric field is applied to the piezoelectric actuators 1258, 1288a, 1288b, such that the inlet orifice 1210 and the outlet orifice 1214 are open to the common chamber 1208. The inlet port 1218 can be connected to a fluid supply source (e.g., Figure 13 the reservoir 1302 in Figure 13 ), and the outlet port 1218 can be connected to a fluid circuit (e.g.,

[0175] the reservoir 1314 in

[0176] ). The pressurized fluid received at the inlet port 1218 can enter the chamber 1208 through the inlet orifice 1210 and fill the chamber 1208. Since the second valve plug 1206 is offset from the outlet nozzle 1216 at this stage, the fluid can be discharged from the chamber 1208 through the outlet orifice 1214 into the outlet port 1220. The filling rate of the chamber 1208 can be faster than the rate at which the fluid is discharged from the chamber 1208. After filling the chamber 1208 with fluid from the inlet port 1218, when no electric field is applied to the piezoelectric actuator 1258, the stroke adjustment device 1264 can be operated to move the first valve plug 1204 to a position where the first valve plug 1204 contacts the end portion of the inlet nozzle 1212 and seals or closes the inlet orifice 1210. When no electric field is applied to the piezoelectric actuators 1288a, 1288b, the stroke adjustment device 1293 can be operated to move the second valve plug 1206 to a position where the second valve plug 1206 contacts the end portion of the outlet nozzle 1216 and seals or closes the outlet orifice 1214. After these adjustments, an electric field can be selectively applied to the piezoelectric actuators 1258, 1288a, 1288b to displace the valve plugs 1204, 1206 from the respective nozzles 1212, 1216 and open the respective orifices 1210, 1214.

[0177] The intake stroke of valve unit 1201 can include opening the inlet orifice 1210 (e.g., controlling the first valve 1203 to an open position) and closing the outlet orifice 1214 (e.g., controlling the second valve 1205 to a closed position) to allow pressurized fluid received at the inlet port 1218 of the valve manifold to enter the common chamber 1208 and fill the chamber 1208 (see Figure 12D ). The rate at which fluid enters chamber 1208 will depend on the size of the inlet gap G1 between the first valve plug 1204 and the end portion of the inlet nozzle 1212 (or inlet orifice 1210) and the pressure of the fluid. The amount of electric field applied to the piezoelectric actuator 1258 determines the size of the inlet gap G1. In some examples, the inlet gap can be in the range of 65 to 70 microns. The fluid received in the common chamber 1208 can leave the common chamber 1208 through the metering port 1222. In some examples, the inlet gap can support a flow rate of up to 0.29 LPM at the metering port.

[0178] The discharge stroke of valve unit 1201 can include closing the inlet orifice 1210 (e.g., controlling the first valve 1203 to a closed position) and opening the outlet orifice 1214 (e.g., controlling the second valve 1205 to an open position). For example, the inlet orifice 1210 can be closed by turning off the electric field applied to the piezoelectric actuator 1258 such that the first valve plug 1204 returns to its position where it contacts the end portion of the inlet nozzle 1212 and seals the inlet orifice 1210. The second orifice 1214 can be opened by applying an electric field to piezoelectric actuators 1288a, 1288b to axially displace the second valve plug 1206 from the outlet nozzle 1216, thereby creating an outlet gap G2 between the second valve plug 1206 and the end portion of the outlet nozzle 1216 (or outlet orifice 1214). The amount of electric field applied to piezoelectric actuators 1288a, 1288b determines the size of the outlet gap G2. In some examples, the outlet gap can be in the range of 130 to 140 microns. The fluid in the common chamber 1208 can flow through the outlet gap and the outlet orifice 1214 to the outlet port 1220.

[0179] Refer to Figure 12G and Figure 12H , in some examples, the metering port 1222 can be an opening in the valve cover 1234 that extends into the common chamber 1208 and is fitted with a fitting 1223. A hydraulic line (e.g., a hose) for a hydraulic actuator can be connected to the fitting 1223. In some examples, a pressure transducer 1225 and an associated measurement circuit can be mounted on the valve cover 1234. The valve cover 1234 can include a passage 1230 that extends from the pressure transducer 1225 to the common chamber 1208 and allows the pressure transducer 1225 to sense pressure changes in the common chamber 1208.

[0180] The pressure transducer 1225, together with the piezoelectric actuators 1258, 1288a, 1288b, can achieve impedance control of the force applied to a hydraulic actuator fluidly connected to the metering port 1222. For example, the pressure measurement performed by the pressure transducer 1225 indicates the pressure in the common chamber 1208, which is the same as the pressure in the fluid line (e.g., Figure 13 the fluid line 1320 in) that connects the hydraulic actuator to the metering port 1222. Using the pressure measurement, the force applied at the output of the hydraulic actuator can be determined and used for impedance control. The valve unit 1201 serves as a proportional valve because the inlet gap G1 between the inlet orifice 1210 and the first valve plug 1204 can be slightly varied by controlling the electric field applied to the piezoelectric actuator 1258.

[0181] In some examples, as Figure 14A and Figure 14B shown, the electrohydraulic valve 1400 can include two valve units 1401a and 1401b disposed on opposite sides of a valve manifold 1402. Each of the valve units 1401a, 1401b can have any of the features and functions described for the valve unit 1201 ( Figure 12A - Figure 12H ). The valve manifold 1402 can have any of the features and functions described for the valve manifold 1202 ( Figure 12A - Figure 12H ). For example, each of the valve units 1401a, 1401b can include common chambers 1408a, 1408b that contain a first valve 1403a, 1403b operable to open or close the inlet orifices 1410a, 1410b and a second valve 1405a, 1405b operable to open or close the outlet orifices 1414a, 1414b. Each valve unit 1401a, 1401b can include metering ports 1422a, 1422b fluidly connected to the respective common chambers 1408a, 1408b. Each of the metering ports 1422a, 1422b can be connected to a respective hydraulic actuator (e.g., a single-acting hydraulic cylinder), or both of the metering ports 1422a, 1422b can be connected to the same hydraulic actuator (e.g., a double-acting hydraulic cylinder). Each valve unit 1401a, 1401b can have a pressure transducer 1425a, 1425b for pressure measurement in the respective common chambers 1408a, 1408b. Each valve unit 1401a, 1401b can have an electrical feedthrough for a valve actuator, a stroke adjustment device, and have other features and functions described for the valve unit 1201. The valve manifold 1402 can have an inlet port 1418 fluidly connected to the inlet orifices 1410a, 1410b and an outlet port 1420 fluidly connected to the outlet orifices 1414a, 1414b.

[0182] Figure 14C The valve bank 1499 is shown including a plurality of electrohydraulic valves 1400 connected in series together. Three electrohydraulic valves 1400 are shown. However, the number of electrohydraulic valves 1400 that may be included in the valve bank 1500 is not limited to three. Generally, the number of electrohydraulic valves 1400 that may be included in the valve bank may depend on the number and type of hydraulic actuators to be connected to the valve bank. For example, a valve bank may be configured with a sufficient number of electrohydraulic valve assemblies to operate a robotic hand ( Figure 9 906 in) that may include a combination of single-acting and double-acting hydraulic cylinders associated with the degrees of freedom of the robotic hand. The electrohydraulic valves 1400 may be connected together using the flange member 1437 of the valve manifold 1402.

[0183] Figure 15 is a simplified circuit diagram of an exemplary hydraulic system 1500 that uses electrohydraulic valves 1400 to deliver fluid to a double-acting hydraulic cylinder 1512. The valve manifold inlet port 1418 (which is fluidly connected to the inlet orifices 1410a, 1410b, as Figure 14B shown) may be fluidly connected to the accumulator 1502 through the main manifold 1518. The accumulator 1502 receives pressurized fluid (e.g., oil) from a pump 1504 that has a suction end fluidly connected to a reservoir 1514. The hydraulic fluid from the pump 1504 to the accumulator 1502 may pass through a direction valve 1516, a high-pressure filter 1506, a check valve 1508, and the main manifold 1518. The hydraulic system 1500 may include a pressure relief valve 1510 fluidly connected to the reservoir 1514. When the hydraulic system is shut down, the pressure relief valve 1510 may bleed the pressure in the accumulator 1302. The metering port 1422a of the valve unit 1401a may be connected to one side of the hydraulic cylinder 1512 via a hydraulic line 1520a, and the metering port 1422b of the valve unit 1401b may be connected to the other side of the hydraulic cylinder 1512 via a hydraulic line 1520b. The valve manifold outlet port 1420 (which is fluidly connected to the outlet orifices 1414a, 1414b, as Figure 14B shown) may be fluidly connected to the reservoir 1514.

[0184] The various embodiments described herein may include or incorporate any or all of the systems, devices, and methods described in the following documents: U.S. patent application Ser. No. 16 / 940,566 (published as US2021-0031383A1), U.S. patent application Ser. No. 17 / 023,929 (published as US2021-0090201A1), U.S. patent application Ser. No. 17 / 061,187 (published as US2021-0122035A1), U.S. patent application Ser. No. 17 / 098,716 (published as US2021-0146553A1), U.S. patent application Ser. No. 17 / 111,789 (published as US2021-0170607A1), U.S. patent application Ser. No. 17 / 158,244 (published as US2021-0234997A1), U.S. non-provisional patent application Ser. No. 17 / 217,650 (published as US2021-0307170A1) and / or U.S. non-provisional patent application Ser. No. 17 / 386,877, and U.S. non-provisional patent application Ser. No. 17 / 749,536, U.S. non-provisional patent application Ser. No. 17 / 833,998, U.S. non-provisional patent application Ser. No. 17 / 863,333, U.S. non-provisional patent application Ser. No. 17 / 867,056, U.S. non-provisional patent application Ser. No. 17 / 871,801, U.S. non-provisional patent application Ser. No. 17 / 976,665 and / or U.S. provisional patent application Ser. No. 63 / 342,414, each of which is incorporated herein by reference in its entirety.

[0185] Throughout this specification and the appended claims, infinitive verb forms are frequently used. Examples include, but are not limited to: "to provide", "to control", etc. Unless the specific context otherwise requires, such infinitive verb forms are used in an open, inclusive sense, i.e., as "to, at least, provide", "to, at least, control", etc.

[0186] This specification (including the drawings and abstract) is not intended to be an exhaustive or restrictive description of all embodiments and examples of the systems, devices, and methods. Those skilled in the art will understand that various descriptions and drawings provided can be modified without departing from the spirit and scope of the disclosure. In particular, the teachings herein are not intended to be limited to or by the illustrative examples of the robotic systems and hydraulic circuits provided.

[0187] The claims of the present disclosure are appended. The present disclosure is intended to support, implement, and illustrate the claims, but is not intended to limit the scope of the claims to any specific embodiment or example. Generally, the claims should be construed to include all possible embodiments and examples together with the full scope of equivalents to which these claims are entitled.

[0188] Another example

[0189] Additional examples based on the principles described herein are listed below. Additional examples falling within the scope of the subject matter can be configured by, for example, separately adopting one feature of an example, adopting more than one feature of an example in combination, or combining one or more features of one example with one or more features of one or more other examples.

[0190] Example 1: A miniaturized hydraulic valve, comprising: a valve body including an inlet and an outlet; a fluid path passing through the valve body, the fluid path being hydraulically communicatively connectable to connect the inlet to the outlet, the fluid path including a nozzle having a diameter within a first range of 600 microns to 700 microns; a plunger positioned in the fluid path near the nozzle; and a piezoelectric material mechanically communicatively connected to the plunger, the position of the plunger relative to the nozzle depending on at least one dimension of the piezoelectric material, the at least one dimension of the piezoelectric material responding to one or more electrical signals from an electrical system, wherein: when in operation the electrical system does not supply power to the piezoelectric material, the plunger is pushed against the nozzle to interrupt the flow of hydraulic fluid along the fluid path, the push being sufficient to interrupt the flow at a fluid pressure of at least 700 pounds per square inch (psi); and when in operation the electrical system supplies power to the piezoelectric material, the plunger is displaced from the nozzle to form a gap between the plunger and the nozzle to allow hydraulic fluid to flow along the fluid path, the gap being proportional to the power supplied to the piezoelectric material, the plunger displacement being within a second range of 40 microns to 70 microns, the gap being sufficient to accommodate a flow rate of hydraulic fluid up to 0.5 liters per minute (lpm).

[0191] Example 2: The miniaturized hydraulic valve according to Example 1, wherein the valve body comprises aluminum or is made of aluminum.

[0192] Example 3: The miniaturized hydraulic valve according to Example 1, wherein the shape of the valve body is cylindrical.

[0193] Example 4: The miniaturized hydraulic valve according to Example 3, wherein at least a portion of the volume of the piezoelectric material is a cylindrical sleeve.

[0194] Example 5: The miniaturized hydraulic valve according to Example 1, wherein at least a portion of the valve body is formed by one of assembling, casting, molding, 3D printing, or machining from a solid cylinder, of a plurality of elements.

[0195] Example 6: The miniaturized hydraulic valve according to Example 1, wherein the hydraulic fluid is oil.

[0196] Example 7: The miniaturized hydraulic valve according to Example 6, wherein the oil is peanut oil having a viscosity in the range of 60 centistokes to 80 centistokes.

[0197] Example 8: The miniaturized hydraulic valve according to Example 1, wherein each of the inlet and the outlet includes a respective through-hole capable of receiving a respective hydraulic fitting, the hydraulic fitting being fluidly connectable to a hydraulic hose.

[0198] Example 9: The miniaturized hydraulic valve according to Example 1, wherein the plunger includes a washer, and wherein the pushing of the plunger against the nozzle to interrupt the flow of hydraulic fluid along the fluid path includes the pushing of the washer against the nozzle.

[0199] Example 10: The miniaturized hydraulic valve according to Example 9, wherein the washer includes polytetrafluoroethylene (PTFE).

[0200] Example 11: The miniaturized hydraulic valve according to Example 1, wherein the electrical system is operable to receive an electrical signal to cause electro-controlled activation of the piezoelectric material to open the pores.

[0201] Example 12: The miniaturized hydraulic valve according to Example 11, wherein the electro-controlled activation of the piezoelectric material includes expansion of the piezoelectric material.

[0202] Example 13: The miniaturized hydraulic valve according to Example 11, wherein the electro-controlled activation of the piezoelectric material includes contraction of the piezoelectric material.

[0203] Example 14: The miniaturized hydraulic valve according to Example 13, wherein the contraction of the piezoelectric material is amplified.

[0204] Example 15: The miniaturized hydraulic valve according to Example 14, wherein the piezoelectric material is an ellipsoid.

[0205] Example 16: The miniaturized hydraulic valve according to Example 1, wherein the piezoelectric material includes lead zirconate titanate.

[0206] Example 17: A hydraulic system includes a miniaturized hydraulic valve and an electrical system. The miniaturized hydraulic valve includes: a valve body that includes an inlet and an outlet; a fluid path through the valve body that hydraulically and communicatively couples the inlet to the outlet, the fluid path including a nozzle having a diameter in a first range of 600 to 700 microns; a plunger positioned in the fluid path adjacent to the nozzle; and a piezoelectric material mechanically communicatively coupled to the plunger, the electrical system communicatively coupled to the piezoelectric material, at least one dimension of the piezoelectric material responsive to one or more electrical signals from the electrical system, and the position of the plunger relative to the nozzle depending on the at least one dimension of the piezoelectric material, wherein: when the electrical system does not supply power to the piezoelectric material during operation, the plunger is pushed against the nozzle to interrupt the flow of hydraulic fluid along the fluid path, the push being sufficient to interrupt the flow at a fluid pressure of at least 700 pounds per square inch (psi); and when the electrical system supplies power to the piezoelectric material during operation, the plunger is displaced from the nozzle to form a gap between the plunger and the nozzle to allow hydraulic fluid to flow along the fluid path, the gap being proportional to the power supplied to the piezoelectric material, the plunger displacement being in a second range of 40 to 70 microns, the gap being sufficient to accommodate a flow rate of hydraulic fluid up to 0.5 liters per minute (lpm).

[0207] Example 18: The hydraulic system according to Example 17 further includes a hydraulic pump, a reservoir, a storage tank, and at least one hydraulic hose.

[0208] Example 19: The hydraulic system according to Example 17, wherein the valve body includes or is made of aluminum.

[0209] Example 20: The hydraulic system according to Example 17, wherein the shape of the valve body is cylindrical.

[0210] Example 21: The hydraulic system according to Example 20, wherein at least a portion of the volume of the piezoelectric material is a cylindrical sleeve.

[0211] Example 22: The hydraulic system according to Example 17, wherein at least a portion of the valve body is formed by one of assembling from a plurality of elements, casting, molding, 3D printing, or machining from a solid cylinder.

[0212] Example 23: The hydraulic system according to Example 17, wherein the hydraulic fluid is oil.

[0213] Example 24: The hydraulic system according to Example 23, wherein the oil is peanut oil having a viscosity in the range of 60 to 80 centistokes.

[0214] Example 25: The hydraulic system according to Example 17, wherein each of the inlet and the outlet includes a respective through-hole capable of receiving a respective hydraulic fitting, and the hydraulic fitting is fluidly connectable to a hydraulic hose.

[0215] Example 26: The hydraulic system according to Example 17, wherein the plunger includes a washer, and wherein the pushing of the plunger against the nozzle to interrupt the flow of hydraulic fluid along the fluid path includes the pushing of the washer against the nozzle.

[0216] Example 27: The hydraulic system according to Example 26, wherein the washer includes polytetrafluoroethylene (PTFE).

[0217] Example 28: The hydraulic system according to Example 17, wherein the electrical system is operable to receive an electrical signal to cause electro-controlled activation of the piezoelectric material to open the pores.

[0218] Example 29: The hydraulic system according to Example 28, wherein the electro-controlled activation of the piezoelectric material includes expansion of the piezoelectric material.

[0219] Example 30: The hydraulic system according to Example 28, wherein the electro-controlled activation of the piezoelectric material includes contraction of the piezoelectric material.

[0220] Example 31: The hydraulic system according to Example 30, wherein the contraction of the piezoelectric material is amplified.

[0221] Example 32: The hydraulic system according to Example 31, wherein the piezoelectric material is an ellipsoid.

[0222] Example 33: The hydraulic system according to Example 17, wherein the piezoelectric material includes lead zirconate titanate.

[0223] Example 34: A robotic arm includes a hydraulic control system physically coupled to a robot body, a hydraulic actuating component physically coupled to the robot body, and a hydraulic assembly. The hydraulic actuating component is operable to cause movement of at least a portion of the robot. The hydraulic assembly includes a miniaturized hydraulic valve and an electrical system. The miniaturized hydraulic valve includes: a valve body that includes an inlet and an outlet; a fluid path through the valve body that hydraulically communicatively couples the inlet to the outlet, the fluid path including a nozzle having a diameter in a first range of 600 microns to 700 microns; a plunger positioned in the fluid path proximate the nozzle; and a piezoelectric material mechanically communicatively coupled to the plunger. The electrical system is communicatively electrically coupled to the piezoelectric material. At least one dimension of the piezoelectric material responds to one or more electrical signals from the electrical system, and the position of the plunger relative to the nozzle depends on the at least one dimension of the piezoelectric material. Wherein: when in operation the electrical system does not supply power to the piezoelectric material, the plunger is urged against the nozzle to interrupt the flow of hydraulic fluid along the fluid path, the urging being sufficient to interrupt the flow at a fluid pressure of at least 700 pounds per square inch (psi); and when in operation the electrical system supplies power to the piezoelectric material, the plunger is displaced from the nozzle to form a gap between the plunger and the nozzle to allow hydraulic fluid to flow along the fluid path, the gap being proportional to the power supplied to the piezoelectric material, the plunger displacement being in a second range of 40 microns to 70 microns, and the gap being sufficient to accommodate a flow rate of hydraulic fluid up to 0.5 liters per minute (lpm).

[0224] Example 35: The robotic arm according to Example 34, wherein the valve body comprises or is made of aluminum.

[0225] Example 36: The robotic arm according to Example 34, wherein the shape of the valve body is cylindrical.

[0226] Example 37: The robotic arm according to Example 36, wherein at least a portion of the volume of the piezoelectric material is a cylindrical sleeve.

[0227] Example 38: The robotic arm according to Example 34, wherein at least a portion of the valve body is formed by one of assembling from a plurality of elements, casting, molding, 3D printing, or machining from a solid cylinder.

[0228] Example 39: The robotic arm according to Example 34, wherein the hydraulic fluid is oil.

[0229] Example 40: The robotic arm according to Example 39, wherein the oil is peanut oil having a viscosity in the range of 60 centistokes to 80 centistokes.

[0230] Example 41: The robotic arm according to Example 34, wherein each of the inlet and the outlet includes a respective through-hole capable of receiving a respective hydraulic fitting, and the hydraulic fitting is capable of being fluidly coupled to a hydraulic hose.

[0231] Example 42: The robotic arm according to Example 34, wherein the plunger includes a gasket, and wherein the pushing of the plunger against the nozzle to interrupt the flow of hydraulic fluid along the fluid path includes the pushing of the gasket against the nozzle.

[0232] Example 43: The robotic arm according to Example 42, wherein the gasket includes polytetrafluoroethylene (PTFE).

[0233] Example 44: The robotic arm according to Example 34, wherein the electrical system is operable to receive an electrical signal to cause electrically controlled activation of the piezoelectric material to open the pores.

[0234] Example 45: The robotic arm according to Example 44, wherein the electrically controlled activation of the piezoelectric material includes expansion of the piezoelectric material.

[0235] Example 46: The robotic arm according to Example 44, wherein the electrically controlled activation of the piezoelectric material includes contraction of the piezoelectric material.

[0236] Example 47: The robotic arm according to Example 46, wherein the contraction of the piezoelectric material is amplified.

[0237] Example 48: The robotic arm according to Example 47, wherein the piezoelectric material is an ellipsoid.

[0238] Example 49: The robotic arm according to Example 34, wherein the piezoelectric material includes lead zirconate titanate.

[0239] Example 50: A robot, comprising a robot main body, a hydraulic control system physically coupled to the robot main body, a hydraulic actuating component physically coupled to the robot main body, and a hydraulic component. The hydraulic actuating component is operable to cause movement of at least a portion of the robot. The hydraulic component includes a miniaturized hydraulic valve and an electrical system. The miniaturized hydraulic valve includes: a valve body including an inlet and an outlet; a fluid path through the valve body that hydraulically communicatively couples the inlet to the outlet. The fluid path includes a nozzle having a diameter in a first range of 600 microns to 700 microns; a plunger positioned in the fluid path proximate to the nozzle; and a piezoelectric material mechanically communicatively coupled to the plunger. The electrical system is communicatively coupled to the piezoelectric material. At least one dimension of the piezoelectric material responds to one or more electrical signals from the electrical system, and the position of the plunger relative to the nozzle depends on the at least one dimension of the piezoelectric material. Wherein: when in operation the electrical system does not supply power to the piezoelectric material, the plunger is pushed against the nozzle to interrupt the flow of hydraulic fluid along the fluid path, and the push is sufficient to interrupt the flow at a fluid pressure of at least 700 pounds per square inch (psi); and when in operation the electrical system supplies power to the piezoelectric material, the plunger is displaced from the nozzle to form a gap between the plunger and the nozzle to allow the hydraulic fluid to flow along the fluid path, and the gap is proportional to the power supplied to the piezoelectric material. The plunger displacement is in a second range of 40 microns to 70 microns, and the gap is sufficient to accommodate a flow rate of hydraulic fluid up to 0.5 liters per minute (lpm).

[0240] Example 51: The robot according to Example 50, wherein the valve body comprises or is made of aluminum.

[0241] Example 52: The robot according to Example 50, wherein the shape of the valve body is cylindrical.

[0242] Example 53: The robot according to Example 52, wherein at least a portion of the volume of the piezoelectric material is a cylindrical sleeve.

[0243] Example 54: The robot according to Example 50, wherein at least a portion of the valve body is formed by one of assembling, casting, molding, 3D printing, or machining from a solid cylinder by a plurality of elements.

[0244] Example 55: The robot according to Example 50, wherein the hydraulic fluid is oil.

[0245] Example 56: The robot according to Example 55, wherein the oil is peanut oil having a viscosity in the range of 60 centistokes to 80 centistokes.

[0246] Example 57: The robot according to Example 50, wherein each of the inlet and the outlet includes a respective through hole capable of receiving a respective hydraulic fitting, and the hydraulic fitting is capable of being fluidly coupled to a hydraulic hose.

[0247] Example 58: The robot according to Example 50, wherein the plunger includes a gasket, and wherein the pushing of the plunger against the nozzle to interrupt the flow of hydraulic fluid along the fluid path includes the pushing of the gasket against the nozzle.

[0248] Example 59: The robot according to Example 58, wherein the gasket includes polytetrafluoroethylene (PTFE).

[0249] Example 60: The robot according to Example 50, wherein the electrical system is operable to receive an electrical signal to cause electrically controlled activation of the piezoelectric material to open the pores.

[0250] Example 61: The robot according to Example 60, wherein the electrically controlled activation of the piezoelectric material includes expansion of the piezoelectric material.

[0251] Example 62: The robot according to Example 60, wherein the electrically controlled activation of the piezoelectric material includes contraction of the piezoelectric material.

[0252] Example 63: The robot according to Example 62, wherein the contraction of the piezoelectric material is amplified.

[0253] Example 64: The robot according to Example 63, wherein the piezoelectric material is an ellipsoid.

[0254] Example 65: The robot according to Example 50, wherein the piezoelectric material includes lead zirconate titanate.

[0255] Example 66: An electrohydraulic valve, comprising: a valve manifold having an inlet port and an outlet port; a valve housing having a common chamber defined therein, a metering port communicating with the common chamber, and a first end coupled to the valve manifold; a first nozzle in fluid communication with the inlet port, the first nozzle having a first nozzle end portion disposed within the common chamber, the first nozzle end portion including a first orifice; a second nozzle in fluid communication with the outlet port, the second nozzle having a second nozzle end portion disposed within the common chamber, the second nozzle end portion including a second orifice; a first valve plug disposed within the common chamber and positioned in a relative relationship with the first orifice; a first valve actuator coupled to the first valve plug and operable to move the first valve plug between a closed position and an open position, in the closed position of the first valve plug, the first valve plug contacts the first nozzle end portion and closes the first orifice, in the open position of the first valve plug, the first valve plug is offset from the first nozzle end portion, and a first gap is created between the first valve plug and the first orifice for allowing fluid to flow from the first orifice into the common chamber; a second valve plug disposed within the common chamber and positioned in a relative relationship with the second orifice; and a second valve actuator coupled to the second valve plug and operable to move the second valve plug between a closed position and an open position, in the closed position of the second valve plug, the second valve plug contacts the second nozzle end portion and closes the second orifice, in the open position of the second valve plug, the second valve plug is offset from the second nozzle end portion, and a second gap is created between the second valve plug and the second orifice for allowing fluid to flow from the common chamber into the second orifice.

[0256] Example 67: The electrohydraulic valve according to Example 66, wherein the first valve actuator includes a first piezoelectric actuator having a first piezoelectric element and a first flexure element, and wherein the first flexure element is coupled to the first valve plug.

[0257] Example 68: The electrohydraulic valve according to Example 67, wherein the second valve actuator includes a second piezoelectric actuator having a second piezoelectric element and a second flexure element, and wherein the second flexure element is coupled to the second valve plug.

[0258] Example 69: The electrohydraulic valve according to Example 68, wherein the second valve actuator includes a third piezoelectric actuator having a third piezoelectric element and a third flexure element, and wherein the third flexure element is coupled to the second flexure element.

[0259] Example 70: The electrohydraulic valve according to Example 66, wherein the valve housing includes a valve body portion and a valve cover portion, the common chamber is defined in the valve body portion, and the valve cover portion encloses one end of the common chamber.

[0260] Example 71: The electrohydraulic valve according to Example 70, further comprising: a first stroke adjustment device, the first stroke adjustment device being coupled to the first valve plug and operable to adjust the position of the first valve plug relative to the first nozzle end portion; and a second stroke adjustment device, the second stroke adjustment device being coupled to the second valve plug and operable to adjust the position of the second valve plug relative to the second nozzle end portion.

[0261] Example 72: The electrohydraulic valve according to Example 71, wherein the first stroke adjustment device includes a first adjustment head coupled to the first valve plug and a first adjustment screw threadedly coupled to the first adjustment head, and wherein rotation of the first adjustment screw causes translation of the first adjustment head along the first adjustment screw.

[0262] Example 73: The electrohydraulic valve according to Example 72, wherein the first adjustment screw is rotatably coupled to the valve cover and axially restricted relative to the valve cover.

[0263] Example 74: The electrohydraulic valve according to Example 72, wherein the first valve actuator includes a first piezoelectric actuator having a first piezoelectric element and a first flexure element, and wherein the first flexure element is coupled to the first valve plug at a first end and to the first adjustment head at a second end.

[0264] Example 75: The electrohydraulic valve according to Example 72, wherein the second stroke adjustment device includes a second adjustment head coupled to the second valve plug and a second adjustment screw threadedly coupled to the second adjustment head, and wherein rotation of the second adjustment screw causes translation of the second adjustment head along the second adjustment screw.

[0265] Example 76: The electrohydraulic valve according to Example 75, wherein the second adjustment screw is rotatably coupled to the valve cover and axially restricted relative to the valve cover.

[0266] Example 77: The electrohydraulic valve according to Example 75, wherein the second valve actuator includes at least one piezoelectric actuator having a piezoelectric element and a flexure element, wherein the flexure element is coupled to the second valve plug at a first side and to the second adjustment head at a second side.

[0267] Example 78: The electrohydraulic valve according to Example 75, wherein the second valve actuator includes a first piezoelectric actuator having a first piezoelectric element and a first flexure element, wherein the second valve actuator includes a second piezoelectric actuator having a second piezoelectric element and a second flexure element, wherein the first flexure element is coupled to the second valve plug at a first side and to a first side of the second flexure element at a second side, and wherein the second flexure element is coupled to the second adjusting head at a second side.

[0268] Example 79: The electrohydraulic valve according to Example 75, wherein the first adjusting head is received within a first bore formed in the valve cover portion and is axially movable within the first bore in response to rotation of the first adjusting screw, and wherein the second adjusting head is received within a second bore formed in the valve cover portion and is axially movable within the second bore in response to rotation of the first adjusting screw.

[0269] Example 80: The electrohydraulic valve according to Example 70, further comprising a pressure transducer coupled to the valve cover portion and an opening in the valve cover portion that forms a pressure communication path between the pressure transducer and the common chamber.

[0270] Example 81: The electrohydraulic valve according to Example 70, further comprising an electrical feedthrough that is coupled to the valve cover portion and is electrically connected within the common chamber to the first valve actuator and the second valve actuator.

[0271] Example 82: The electrohydraulic valve according to Example 81, wherein the metering port is formed in the valve cover portion and includes a fitting for connecting a hydraulic fluid line.

[0272] Example 83: The electrohydraulic valve according to Example 66, wherein the valve manifold includes a first bore connected to the inlet port and a second bore connected to the outlet port, wherein the first nozzle is mounted within the first bore, wherein a first nozzle end portion projects into the common chamber, and wherein the second nozzle is mounted within the second bore, wherein a second nozzle end portion projects into the common chamber.

[0273] Example 84: The electrohydraulic valve according to Example 66, wherein a portion of the first valve plug positioned in a relative relationship with the first orifice includes a first sealing member, and wherein a portion of the second valve plug positioned in a relative relationship with the second orifice includes a second sealing member.

[0274] Example 85: A method of operating a hydraulic actuator, comprising: applying an electric field to a first valve actuator disposed in a common chamber of a valve unit to axially displace a first valve plug disposed in the common chamber from a first orifice connected to an inlet port of a valve manifold and form a first communication path between the inlet port and the common chamber through the first orifice; conveying fluid from a fluid source connected to the inlet port to the common chamber through the first communication path; conveying the fluid from the common chamber to the hydraulic actuator through a metering port of the valve unit; removing the electric field from the first valve actuator to bias the first valve plug against the first orifice and close the first communication path; applying an electric field to a second valve actuator disposed in the common chamber of the valve unit to axially displace a second valve plug disposed in the common chamber from a second orifice connected to an outlet port of the valve manifold and form a second communication path between the outlet port and the common chamber through the second orifice; and discharging the fluid from the common chamber to a fluid circuit connected to the outlet port through the second communication path.

Claims

1. An electro-hydraulic valve, comprising: A valve manifold having an inlet port and an outlet port; A valve housing having a common chamber defined therein, a metering port in communication with the common chamber, and a first end coupled to the valve manifold; A first nozzle in fluid communication with the inlet port, the first nozzle having a first nozzle end portion disposed within the common chamber, the first nozzle end portion including a first orifice; A second nozzle in fluid communication with the outlet port, the second nozzle having a second nozzle end portion disposed within the common chamber, the second nozzle end portion including a second orifice; A first valve plug disposed within the common chamber and positioned in a relative relationship with the first orifice; A first valve actuator coupled to the first valve plug and operable to move the first valve plug between a closed position and an open position, in the closed position of the first valve plug, the first valve plug contacts the first nozzle end portion and closes the first orifice, in the open position of the first valve plug, the first valve plug is offset from the first nozzle end portion, and a first gap is created between the first valve plug and the first orifice for allowing fluid to flow from the first orifice into the common chamber; A second valve plug disposed within the common chamber and positioned in a relative relationship with the second orifice; And A second valve actuator coupled to the second valve plug and operable to move the second valve plug between a closed position and an open position, in the closed position of the second valve plug, the second valve plug contacts the second nozzle end portion and closes the second orifice, in the open position of the second valve plug, the second valve plug is offset from the second nozzle end portion, and a second gap is created between the second valve plug and the second orifice for allowing fluid to flow from the common chamber into the second orifice.

2. The electro-hydraulic valve according to claim 1, wherein, The first valve actuator includes a first piezoelectric actuator having a first piezoelectric element and a first flexure element, and wherein the first flexure element is coupled to the first valve plug.

3. The electro-hydraulic valve according to claim 2, wherein, The second valve actuator includes a second piezoelectric actuator having a second piezoelectric element and a second flexure element, and wherein the second flexure element is coupled to the second valve plug.

4. The electro-hydraulic valve according to claim 3, wherein, The second valve actuator includes a third piezoelectric actuator having a third piezoelectric element and a third flexure element, and wherein the third flexure element is coupled to the second flexure element.

5. The electro-hydraulic valve according to claim 1, wherein, The valve housing includes a valve body portion and a valve cover portion, the common chamber is defined in the valve body portion, and the valve cover portion encapsulates one end of the common chamber.

6. The electro-hydraulic valve according to claim 5, further comprising: A first stroke adjustment device coupled to the first valve plug and operable to adjust the position of the first valve plug relative to the first nozzle end portion; And A second stroke adjustment device, the second stroke adjustment device being coupled to the second valve plug and operable to adjust the position of the second valve plug relative to the second nozzle end portion.

7. The electro-hydraulic valve according to claim 6, wherein, The first stroke adjustment device includes a first adjustment head coupled to the first valve plug and a first adjustment screw threadedly coupled to the first adjustment head, and wherein rotation of the first adjustment screw causes translation of the first adjustment head along the first adjustment screw.

8. The electro-hydraulic valve according to claim 7, wherein, The first adjustment screw is rotatably coupled to the valve cover and is axially restricted relative to the valve cover.

9. The electro-hydraulic valve according to claim 7, wherein, The first valve actuator includes a first piezoelectric actuator having a first piezoelectric element and a first flexure element, and wherein the first flexure element is coupled to the first valve plug at a first end and to the first adjustment head at a second end.

10. The electro-hydraulic valve according to claim 7, wherein, The second stroke adjustment device includes a second adjustment head coupled to the second valve plug and a second adjustment screw threadedly coupled to the second adjustment head, and wherein rotation of the second adjustment screw causes translation of the second adjustment head along the second adjustment screw.

11. The electro-hydraulic valve according to claim 10, wherein, The second adjustment screw is rotatably coupled to the valve cover and is axially restricted relative to the valve cover.

12. The electro-hydraulic valve according to claim 10, wherein, The second valve actuator includes at least one piezoelectric actuator having a piezoelectric element and a flexure element, wherein the flexure element is coupled to the second valve plug at a first side and to the second adjustment head at a second side.

13. The electro-hydraulic valve according to claim 10, wherein, The second valve actuator includes a first piezoelectric actuator having a first piezoelectric element and a first flexure element, wherein the second valve actuator includes a second piezoelectric actuator having a second piezoelectric element and a second flexure element, wherein the first flexure element is coupled to the second valve plug at a first side and to a first side of the second flexure element at a second side, and wherein the second flexure element is coupled to the second adjustment head at a second side.

14. The electro-hydraulic valve according to claim 10, wherein, The first adjustment head is received within a first hole formed in the valve cover portion and is axially movable within the first hole in response to rotation of the first adjustment screw, and wherein the second adjustment head is received within a second hole formed in the valve cover portion and is axially movable within the second hole in response to rotation of the first adjustment screw.

15. The electro-hydraulic valve according to claim 5, further comprising a pressure transducer coupled to the valve cover portion and an opening in the valve cover portion, the opening forming a pressure communication path between the pressure transducer and the common chamber.

16. The electro-hydraulic valve according to claim 5, further comprising an electrical feedthrough coupled to the valve cover portion and electrically connected within the common chamber to the first valve actuator and the second valve actuator.

17. The electro-hydraulic valve according to claim 16, wherein, The metering port is formed in the valve cover portion and includes a fitting for connecting a hydraulic fluid line.

18. The electro-hydraulic valve according to claim 1, wherein, The valve manifold includes a first orifice connected to the inlet port and a second orifice connected to the outlet port, wherein the first nozzle is mounted within the first orifice, wherein an end portion of the first nozzle protrudes into the common chamber, and wherein the second nozzle is mounted within the second orifice, wherein an end portion of the second nozzle protrudes into the common chamber.

19. The electro-hydraulic valve according to claim 1, wherein, A portion of the first valve plug positioned in a relative relationship with the first orifice includes a first sealing member, and wherein, a portion of the second valve plug positioned in a relative relationship with the second orifice includes a second sealing member.

20. A method of operating a hydraulic actuator, comprising: Applying an electric field to a first valve actuator disposed within a common chamber of a valve unit to axially displace a first valve plug disposed within the common chamber from a first orifice connected to an inlet port of a valve manifold and form a first communication path between the inlet port and the common chamber through the first orifice; Conveying fluid from a fluid source connected to the inlet port through the first communication path to the common chamber; Conveying the fluid from the common chamber to a hydraulic actuator through a metering port of the valve unit; Removing the electric field from the first valve actuator to bias the first valve plug against the first orifice and close the first communication path; Applying an electric field to a second valve actuator disposed within the common chamber of the valve unit to axially displace a second valve plug disposed within the common chamber from a second orifice connected to an outlet port of the valve manifold and form a second communication path between the outlet port and the common chamber through the second orifice; and Discharging fluid from the common chamber through the second communication path to a fluid circuit connected to the outlet port.

Images