Patent Application
20220268268
The present disclosure generally relates to actuators and, more particularly, actuators that can operate two-stage pumps, and provide increased flow rates for multi-stage pumps.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it may be described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present technology.
Control systems can be employed for the actuation and positioning of a remote object or the like, including pneumatic, hydraulic, and electromechanical systems. These control systems can be used to control the movement of a variety of objects, such as autonomous devices, prosthetics, robotics, and inflatable structures. Each of these types of systems has particular advantages under certain conditions. Pneumatic systems can supply force through the delivery of a compressed gas, whereas hydraulic systems rely on minimally compressible liquids. Furthermore, high pressures can be employed which reduces the size of the operating equipment. However, hydraulic fluids are often not fire proof, and hydraulic systems may be susceptible to leakage and high maintenance, particularly in control applications. Electromechanical systems rely on electrically moveable components, and can include combinations of the previous systems (e.g., electro-pneumatic and electro-hydraulic systems).
Hydraulically-amplified, self-healing, electrostatic (HASEL) actuators use electric fields and hydraulic forces to locally displace a liquid dielectric material that is generally enclosed in a soft hydraulic architecture. For example, electrostatic forces between electrode pairs of the actuators (generated upon application of a voltage to the electrode pairs) draws the electrodes in each pair towards each other, displacing the liquid dielectric to drive actuation in various manners. However, losses in speed, pressure, and efficiency associated with transporting fluid through such an architecture may limit certain applications. Accordingly, there remains a need for more robust designs of actuators.
This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.
In various aspects, the present teachings provide a two-stage pump system using electrostatic actuators. The two-stage pump system includes a pair of hydraulically-amplified, self-healing, electrostatic (HASEL) actuators. Each HASEL actuator is in fluid communication with one another, and includes a deformable shell defining a working fluid compartment. A dielectric fluid is disposed in the working fluid compartment. Two electrodes are disposed on opposite sides of the deformable shell. A first transfer conduit is provided, enabling two-way fluid communication between the working fluid compartments of the pair of HASEL actuators. The two-stage pump system also includes a pair of fluid transfer bladders disposed adjacent the respective pair of HASEL actuators. Each fluid transfer bladder is configured for pumping a transfer fluid from an inlet to an outlet, and includes a fluid-impermeable membrane defining a transfer fluid chamber. A biasing member is disposed in the transfer fluid chamber. A second transfer conduit is provided, enabling selective fluid communication between the pair of fluid transfer bladders. When individually actuated in an alternating two-stage pattern, the two electrodes of each respective HASEL actuator move from a neutral position to an attracted position, displacing dielectric fluid through the first transfer conduit and between working fluid compartments, thereby pumping the transfer fluid from the inlet to the outlet.
In other aspects, the present teachings provide a continuous pump system using electrostatic actuators. The continuous pump system includes a plurality of two-stage pumps coupled in a parallel manner to a common fluid conduit. Each two-stage pump includes a pair HASEL actuators. Each HASEL actuator is in fluid communication with one another, and includes a deformable shell defining a working fluid compartment. A dielectric fluid is disposed in the working fluid compartment. Two electrodes are disposed on opposite sides of the deformable shell. A first transfer conduit is provided, enabling two-way fluid communication between the working fluid compartments of the pair of HASEL actuators. The two-stage pump system also includes a pair of fluid transfer bladders disposed adjacent the respective pair of HASEL actuators. Each fluid transfer bladder is configured for pumping a transfer fluid from an inlet to an outlet, and includes a fluid-impermeable membrane defining a transfer fluid chamber. A biasing member is disposed in the transfer fluid chamber. A second transfer conduit is provided, enabling selective fluid communication between the pair of fluid transfer bladders. When individually actuated in an alternating two-stage pattern, the two electrodes of each respective HASEL actuator move from a neutral position to an attracted position, displacing dielectric fluid through the first transfer conduit and between working fluid compartments, thereby pumping the transfer fluid from the inlet to the outlet. Each of the plurality of two stage pumps is configured to alternatingly output fluid to the common fluid conduit.
In still other aspects, the present teachings provide a multi-stage pump system using electrostatic actuators. The multi-stage pump system includes a plurality of two-stage pumps coupled in a stacked series manner and configured to increase a pressure along a common fluid conduit. Each two-stage pump includes a pair HASEL actuators. Each HASEL actuator is in fluid communication with one another, and includes a deformable shell defining a working fluid compartment. A dielectric fluid is disposed in the working fluid compartment. Two electrodes are disposed on opposite sides of the deformable shell. A first transfer conduit is provided, enabling two-way fluid communication between the working fluid compartments of the pair of HASEL actuators. The two-stage pump system also includes a pair of fluid transfer bladders disposed adjacent the respective pair of HASEL actuators. Each fluid transfer bladder is configured for pumping a transfer fluid from an inlet to an outlet, and includes a fluid-impermeable membrane defining a transfer fluid chamber. A biasing member is disposed in the transfer fluid chamber. A second transfer conduit is provided, enabling selective fluid communication between the pair of fluid transfer bladders. When individually actuated in an alternating two-stage pattern, the two electrodes of each respective HASEL actuator move from a neutral position to an attracted position, displacing dielectric fluid through the first transfer conduit and between working fluid compartments, thereby pumping the transfer fluid from the inlet to the outlet. Each of the plurality of two stage pumps is configured to output fluid to the common fluid conduit.
The present teachings will become more fully understood from the detailed description and the accompanying drawings, wherein:
It should be noted that the figures set forth herein are intended to exemplify the general characteristics of the methods, algorithms, and devices among those of the present technology, for the purpose of the description of certain aspects. These figures may not precisely reflect the characteristics of any given aspect, and are not necessarily intended to define or limit specific embodiments within the scope of this technology. Further, certain aspects may incorporate features from a combination of figures.
The various aspects disclosed herein generally relate to a liquid electroactive polymer (EAP) actuator for the operation of soft pumps. In particular, the present teachings provide a soft, two-stage pump system using electrostatic actuators. The two-stage pump system includes a pair of hydraulically-amplified, self-healing, electrostatic (HASEL) actuators. Each HASEL actuator of the pair is in fluid communication with one another, and includes a deformable shell defining a working fluid compartment. A dielectric fluid is disposed in the working fluid compartment. Two electrodes are disposed on opposite sides of each deformable shell. A first transfer conduit is provided, enabling two-way fluid communication between the working fluid compartments of the pair of HASEL actuators. The two-stage pump system also includes a pair of fluid transfer bladders disposed adjacent the respective pair of HASEL actuators. Each fluid transfer bladder is configured for pumping a transfer fluid from an inlet to an outlet, and includes a fluid-impermeable membrane defining a transfer fluid chamber. A biasing member is disposed in the transfer fluid chamber. A second transfer conduit is provided, enabling selective fluid communication between the pair of fluid transfer bladders. When individually actuated in an alternating two-stage pattern, the two electrodes of each respective HASEL actuator move from a neutral position to an attracted position, displacing dielectric fluid through the first transfer conduit and between working fluid compartments, thereby pumping the transfer fluid from the inlet to the outlet. High flow rates can be achieved by using complementary, or multi-stage (a series of at least two), soft pumps for a continuous flow.
As shown in
In various aspects, the controller(s) may be configured to control and operate a plurality of two-stage pumps in different phases, as well as control and operate a plurality of two-stage pumps arranged in a series or stacked series manner in order to successively increase a pressure of the transfer fluid. For example, the conductive electrodes 44 of the actuators 22, 24 have a deactivated state, such that the electrodes 44 do not compress the deformable shells 38. When power is supplied to the electrodes 44, it causes an electrostatic attraction, where the electrodes 44 move toward each other, to have an activated state. When the electrodes 44 move toward one another in the activated state, dielectric fluid 42 is displaced in a lateral direction, out of the working fluid compartment 40 and into an adjacent actuator. When the electrodes 44 move away from one another in the deactivated state (no applied current), the dielectric fluid 42 is returned from the adjacent actuator into the original working fluid compartment 40. Switching between the deactivated and activated states causes a pumping action that moves the transfer fluid. The implementations disclosed herein are described in more detail with reference to the figures herein.
Each of the fluid transfer bladders 26, 28 may be disposed adjacent a respective pair of HASEL actuators 22, 24. For example, the first fluid transfer bladder 26 is shown adjacent to and controlled by the first HASEL actuator 22, and the second fluid transfer bladder 28 is shown adjacent to and controlled by the second HASEL actuator 24. In certain aspects, each fluid transfer bladder 26, 28 may be physically coupled to a respective one of the pair of HASEL actuators 22, 24. The fluid transfer bladders 26, 28 may include a fluid-impermeable membrane 46 that defines a transfer fluid chamber 48 and contains the transfer fluid 30. At least one biasing member 52, 54 may be disposed in each respective fluid transfer bladder 26, 28. In various aspects, one of the biasing members 52 may be a compressive biasing member, such as a spring or the like, having a first spring constant K1, while the other biasing member 54 may be provided to exhibit a tensile biasing force, such as a rubberband or the like, having a second spring constant K2. Different combinations of biasing members may be used depending on the specific design. In most instances, each biasing member 52, 54 will have a different spring constant associated therewith.
A first transfer conduit 56 may be included, providing two-way fluid communication between the respective working fluid compartments 40 of the pair of HASEL actuators 22, 24. Similarly, a second transfer conduit 58 can be including, providing selective fluid communication between the respective transfer fluid chambers 48 of the fluid transfer bladders 26, 28. It should be understood that the specific shapes and sizes of the HASEL actuators 22, 24, the fluid transfer bladders 26, 28, and the fluid transfer conduits 56, 58 may vary, and the shapes and relative dimensions provided in the figures are for illustrative purposes. A number of one-way valves 60, or check valves, may be provided at certain locations. For example, a one way valve 60 may be provided adjacent the inlet 32, adjacent the outlet 34, and adjacent or within the second transfer conduit 58 in order to selectively control the direction of flow, and to prevent backflow of the transfer fluid 30.
Operation of the two-stage pumps 20 can be best understood with reference to the differences in stages between
When alternating from the first stage shown in
When alternating from the second stage shown in
As shown in
The deformable shell 38, as well as portions 38a, 38b thereof, and can include a polymer, an elastomeric polymer (elastomer) or both. In various aspects, the deformable shell 38 includes an electroactive polymer (EAP). The use of a plurality of different encapsulating elastomers and/or polymers of varying degrees of softness and hardness can be employed. The polymers used in the implementations described herein can further include the addition of a plasticizer, such as phthalate esters. The polymers or elastomers may be natural or synthetic. Examples of elastomers usable as part of an external insulating portion can include an insulating elastomer, such as nitrile, ethylene propylene diene monomer (EPDM), fluorosilicone (FVMQ), vinylidene fluoride (VDF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), perfluoromethylvinylether (PMVE), polydimethylsiloxane (PDMS), natural rubber, neoprene, polyurethane, silicone, silicone rubber, or combinations thereof. Any external insulating portion can be described with regard to electrical insulation. The electrical insulation of any external insulating portion can be described in relation to the dielectric constant, or κ value, of said material, such as having a higher or lower dielectric constant. The term “elastomer,” as used herein, means a material which can be stretched by an external force at room temperature to at least twice its original length, and then upon immediate release of the external force, can return to its original length. Room temperature can generally refer to a temperature in a range of from about 20° C. to about 25° C. Elastomers, as used herein, can include a thermoplastic, and may be cross-linked or thermosetarious aspects, the conducting electrodes 44, or portions thereof, are conductive to electrical current, such that the conducting portion creates an electric field. In certain aspects, conducting portions can include hydrogels, and can further include a polymer, an elastomeric polymer (elastomer) or both. Examples of elastomers usable as part of the conducting portions can include nitrile, EPDM, fluorosilicone (FVMQ), vinylidene fluoride (VDF), hexafluoropropylene (HFP), tetrafluoroethylene (TFE), perfluoromethylvinylether (PMVE), polydimethylsiloxane (PDMS), natural rubber, neoprene, polyurethane, silicone, or combinations thereof. The conducting portions can be composed or further include a conductive material, such as an electrically conductive dopant. Electrically conductive dopants can include silver, gold, platinum, copper, aluminum, or others. In further implementations, the conducting portions can include inks and adhesives, for the purpose of flexibility and/or conductivity.
The dielectric fluid 42 can be a fluid that is resistant to electrical breakdown and/or provides insulation. In one or more implementations, the dielectric fluid 42 can prevent arcing between one or more opposing layers or portions of the deformable shell 38. The dielectric fluid 42 can be a lipid based fluid, such as a vegetable oil-based dielectric fluid. In one implementation, the dielectric fluid 42 can be ethylene glycol. The dielectric fluid 42 can be selected based on desired dielectric constant, or κ value.
Materials suitable for use as an electroactive polymer (EAP), in the one or more implementations described herein, can include any insulating polymer or rubber (or a combination thereof) that deforms in response to an electrostatic force or whose deformation results in a change in electric field. Exemplary materials suitable for use as an electroactive polymer can include silicone elastomers, acrylic elastomers, polyurethanes, thermoplastic elastomers, copolymers comprising PVDF, pressure-sensitive adhesives, fluoroelastomers, polymers comprising silicone and acrylic moieties, and the like. Polymers, such as those including silicone and acrylic moieties, can include copolymers having silicone and acrylic moieties, polymer blends having a silicone elastomer and an acrylic elastomer, or others. Combinations of some of these materials may also be used. Materials used as an electroactive polymer can be selected based on one or more material properties. Material properties used for selection can include a high electrical breakdown strength, a low modulus of elasticity (such as for controlling the level of deformation), or others.
In the description above, certain specific details are outlined in order to provide a thorough understanding of various implementations. However, one skilled in the art will understand that the invention may be practiced without these details. In other instances, well-known structures have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the implementations. Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limited to.” Further, headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed invention.
Reference throughout this specification to “one or more implementations” or “an implementation” means that a particular feature, structure or characteristic described in connection with the implementation is included in at least one or more implementations. Thus, the appearances of the phrases “in one or more implementations” or “in an implementation” in various places throughout this specification are not necessarily all referring to the same implementation. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations. Also, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
Detailed implementations are disclosed herein. However, it is to be understood that the disclosed implementations are intended only as examples. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the aspects herein in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of possible implementations. Various implementations are shown in
The flowcharts and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, devices, and computer program products according to various implementations. In this regard, each block in the flowcharts or block diagrams can represent a module, segment, or portion of code, which can include one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in some alternative implementations, the functions noted in the block can occur out of the order noted in the figures. For example, two blocks shown in succession can, in fact, be executed substantially concurrently, or the blocks can sometimes be executed in the reverse order, depending upon the functionality involved.
The systems, components and/or methods described above can be realized in hardware or a combination of hardware and software and can be realized in a centralized fashion in one processing system or in a distributed fashion where different elements are spread across several interconnected processing systems. Any kind of processing system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software can be a processing system with computer-usable program code that, when being loaded and executed, controls the processing system such that it carries out the methods described herein. The systems, components and/or methods also can be embedded in a computer-readable storage, such as a computer program product or other data programs storage device, readable by a machine, tangibly embodying a program of instructions executable by the machine to perform methods and methods described herein. These elements also can be embedded in an application product which can include all the features enabling the implementation of the methods described herein and, which when loaded in a processing system, can carry out these methods.
The headings (such as “Background” and “Summary”) and sub-headings used herein are intended only for general organization of topics within the present disclosure and are not intended to limit the disclosure of the technology or any aspect thereof. The recitation of multiple implementations having stated features is not intended to exclude other implementations having additional features, or other implementations incorporating different combinations of the stated features. As used herein, the terms “comprise” and “include” and their variants are intended to be non-limiting, such that recitation of items in succession or a list is not to the exclusion of other like items that may also be useful in the devices and methods of this technology. Similarly, the terms “can” and “may” and their variants are intended to be non-limiting, such that recitation that an implementation can or may comprise certain elements or features does not exclude other implementations of the present technology that do not contain those elements or features.
The broad teachings of the present disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the specification and the following claims. Reference herein to one aspect, or various aspects means that a particular feature, structure, or characteristic described in connection with an implementation or particular system is included in at least one or more implementations or aspect. The appearances of the phrase “in one aspect” (or variations thereof) are not necessarily referring to the same aspect or implementation. It should also be understood that the various method steps discussed herein do not have to be carried out in the same order as depicted, and not each method step is required in each aspect or implementation.
The terms “a” and “an,” as used herein, are defined as one as or more than one. The term “plurality,” as used herein, is defined as two or more than two. The term “another,” as used herein, is defined as at least a second or more. The terms “including” and/or “having,” as used herein, are defined as including (i.e., open language). The phrase “at least one of . . . and . . . ” as used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. As an example, the phrase “at least one of A, B and C” includes A only, B only, C only, or any combination thereof (e.g., AB, AC, BC or ABC).
The preceding description of the implementations has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular implementation are generally not limited to that particular implementation, but, where applicable, are interchangeable and can be used in a selected implementation, even if not specifically shown or described. The same may also be varied in many ways. Such variations should not be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
While the preceding is directed to implementations of the disclosed devices, systems, and methods, other and further implementations of the disclosed devices, systems, and methods can be devised without departing from the basic scope thereof. The scope thereof is determined by the claims that follow.
