FLUIDIC ACTUATOR SYSTEMS AND METHODS FOR MOBILE ROBOTS

An exoskeleton system comprising an inflatable actuator configured to be worn by a user. The inflatable actuator includes a fluid-impermeable member that defines a fluid chamber at least in part by a membrane material and a first and second interface that each define sidewalls, the membrane material is coupled to the sidewalls of the first and second interfaces.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1illustrates an example of an exoskeleton comprising a fluidic actuator coupled about the ankle of a user.

FIG. 2is an example illustration of an embodiment of an exoskeleton system being worn on two legs of a user.

FIG. 3is block diagram of an exoskeleton system.

FIG. 4aillustrates a perspective view of an example embodiment of a fluidic actuator in a first configuration and comprising a first and second interface and a fluid impermeable member.

FIG. 4billustrates a perspective view of the example embodiment of the fluidic actuator ofFIG. 4ain a second inflated configuration.

FIG. 5illustrates an example planar material that is substantially inextensible along one or more plane axes of the planar material while being flexible in other directions.

FIG. 6aillustrates a side view of an example fluidic actuator coupled about the ankle of a user.

FIG. 6billustrates a cross-sectional view of the leg of a user and the fluidic actuator ofFIG. 6a.

FIG. 7illustrates a side cross sectional view of an example construction method of fluidic actuator where a welding tool generates a weld between a membrane material and two interfaces about an external edge of the interfaces.

FIG. 8illustrates a side cross sectional view of an example actuator comprising a plurality of sensors on or about interfaces of the actuator.

FIG. 9is a side view of one example embodiment of an actuator coupled to the leg of a user that includes a load cell integrated into an interface that can be configured to measure the force application of the fluidic actuator through an exoskeleton foot structure into the ground.

FIGS. 10aand 10billustrate an example of a support element that is configured to couple about and support welds between a membrane material and sidewalls of an interface.

FIG. 10cillustrates an example where a weld of an actuator has failed via a portion of membrane material decoupling from the interface.

FIG. 11aillustrates an example embodiment of a fluid-impermeable membrane material and a pair of interfaces.

FIG. 11billustrates a fluidic actuator that can be generated by coupling the fluid-impermeable membrane material and a pair of interfaces ofFIG. 11a.

FIG. 12aillustrates example of four pieces of material of two shapes that can be generated for constructing a fluid impermeable member of a fluidic actuator.

FIG. 12billustrates a side view of a fluid impermeable member generated by the four pieces of material ofFIG. 12a.

FIG. 12cillustrates a side cross-sectional view of a fluid impermeable member generated by the four pieces of material ofFIG. 12a.

FIG. 13aillustrates a side cross-sectional view of a fluidic actuator having first and second opposing parallel interfaces with a membrane material coupled thereto having first and second sides with the first side being shorter than the second side.

FIG. 13billustrates a configuration of the actuator ofFIG. 13awhere the interfaces are in a parallel configuration where the first side has reached a maximum length, whereas the second side has not reached a maximum length.

FIG. 13cillustrates a configuration of the actuator ofFIGS. 13aand 13bwhere both the first and second sides have reached a maximum length such that the interfaces are disposed at an angle relative to each other.

FIG. 14aillustrates an example of a peel weld between a first and second element.

FIG. 14billustrates a lap weld between a first and second element.

FIG. 15illustrates an example embodiment of a fluid impermeable member comprising a first and second portion of membrane material coupled together via welds to define a fluid chamber.

FIGS. 16aand 16billustrate respective configurations of a fluid impermeable member defined by portions of a membrane material coupled together at a plurality of welds to define a fluid chamber having a first and second fluid chamber portion.

FIG. 17aillustrates top view of a fluidic actuator having a trapezoidal interface with a membrane material coupled about an edge of the interface via a weld.

FIG. 17billustrates top view of a fluidic actuator having a rectangular interface with a membrane material coupled about an edge of the interface via a weld.

FIG. 18illustrates an embodiment of a fluidic actuator having a first and second interface where the first interface comprises an inlet nozzle that defines an inlet channel and where the second interface comprises an outlet nozzle that defines an outlet channel.

FIGS. 19aand 19billustrate two configurations of a multi-chamber fluidic actuator coupled to the leg and foot of a user configured to cause rotation about the ankle of the user.

FIG. 20illustrates an example embodiment of a fluidic actuator comprising a first and second interface, where a membrane material extends between the interfaces and is coupled to an external face of the interfaces via a weld.

FIG. 21aillustrates a side cross-sectional view of an example embodiment of an actuator comprising a fluid chamber having a first and second sub-chamber defined by first and second welds with one or more straps can be coupled to portions of membrane material about the first and second welds that can constrain expansion of the fluid chamber.

FIG. 21billustrates a side view of an example embodiment of an actuator comprising straps coupled to and extending between a pair of opposing interfaces, which can constrain expansion of a fluid impermeable member between the interfaces.

DETAILED DESCRIPTION

This application discloses examples of fluidic actuators that can be used in mobile robots such as exoskeletons worn by human users. Methods of making and designing such fluidic actuators are disclosed herein as well along with methods of using such actuators. In some embodiments, fluidic actuators can be small relative to the human body and can be able to reach high pressures (e.g., from 5 psig to 100 psig or more).

Turning toFIG. 1, an example lower-leg exoskeleton100is shown coupled to a user101about the leg102, including the foot103and ankle104. In this example, the lower-leg exoskeleton100is shown coupled about the tarsals105, metatarsals106, heel107and shin108.

The lower-leg exoskeleton100is shown comprising a foot structure110that is coupled to an actuator140at a first actuator end141, and further comprising a shin structure150coupled at a second actuator end142. The foot structure110is shown including sidewalls112and a base114, which define a slot116in which the foot103of the user101can be disposed. A base strap120is illustrated being coupled to the foot structure110and encircling a portion of the foot103. A heel strap130is illustrated being coupled to the foot structure110and encircling a portion of the heel107.

In this example, the sidewalls112define a generally C-shaped portion of the foot structure110with the base114being substantially planar and engaging a bottom portion of the foot103. The foot structure110can be rigid and comprise materials such as plastic, metal or the like. In various embodiments, the base114can provide a load-path contact point forward of the heel107of a user, such as at or forward of the tarsals105or metatarsals106.

In further embodiments, the foot structure110can comprise and/or be defined by inflatable structures that surround portions of the foot103, including the tarsals105and/or metatarsals106. In other words, structures such as the sidewalls112, base114, base strap120, heel strap130, or the like, can comprise an inflatable structure. In one example, inflatable structures can be positioned on the sole of the foot103, which can be configured to spread a load generated while walking evenly across the ground or other surface being walked on.

Although the foot structure110is shown in one example configuration inFIG. 1, it should be clear that various other suitable configurations of a foot structure110are within the scope and spirit of the present disclosure. For example, a rigid superstructure can attach beneath the sole of the foot103and can skirt around the foot103to provide a force transmission platform above the foot103.

In further embodiments, the lower-leg exoskeleton100can be configured to be worn over clothing and/or footwear such as a conventional boot, shoe, or the like. However, in some embodiments, a portion of the lower-leg exoskeleton100can be disposed in, comprise, or be integrally coupled with a boot, shoe, or the like. In other words, some examples provide specialized footwear for use with the lower-leg exoskeleton100, which can incorporate portions of the lower-leg exoskeleton100or otherwise be specifically configured to be used with or coupled with the lower-leg exoskeleton100. For example, structures such as the sidewalls112, base114, base strap120, heel strap130, or the like, can be disposed in or be defined by a portion of a shoe or boot.

In another embodiment, a boot or shoe can comprise a segmented structure that comprises a system of rigid panels connected by a flexible joint (e.g., an elastomer) that allows for in-plane rotation, (e.g., “in the plane” can include where the ankle rotates towards and away from the shin), and/or lateral motion. In a further embodiment, a structure in the heel of a shoe or boot can be configured to provide a load path for a reaction force that acts to lift the heel107of the user101.

FIG. 1illustrates an example composite structure that can act as an ankle actuation and passive support structure for a single-sided, single degree-of-freedom (DOF) ankle actuator. The example configuration shown inFIG. 1comprises an inflatable actuator140coupled with rigid passive components (e.g., the foot structure110and the shin structure150) to transfer torque generated by the actuator140to the user101. Accordingly, in various embodiments, one or more rigid components associated with the sole of the foot103can be of sufficient strength to take the load of the actuator140. In various embodiments as described in further detail herein, the inflatable actuator140can provide a moment about the ankle104of the user101. For example, the foot structure110can be connected via a feature in the sole of a shoe that allows the user101to dorsiflex and/or plantar flex his or her foot103.

Plantarflexion torque can be provided by inflating the actuator140. In this example configuration, the actuator140may only connect to the footwear at a load transmission point, but this should not be construed to limit the many alternative embodiments of the design. Other versions of this system can be integrated in various suitable ways. For example, in some cases, the actuator140and footwear can encompass a single piece of hardware that is designed for a specific user (or for a specific size leg and foot), and thus can be smaller in some embodiments.

In some embodiments the rigid foot structure110comprises: a pair of sidewalls112configured to extend around the foot103of a user101and including first and second sidewall attachment points115, respectively, on the sidewalls112for attachment with a removable base portion117, and a removable flat base portion117configured to reside at the base of the foot of the user that includes first and second base attachment points119configured for removably coupling with the first and second sidewall attachment points, the removable flat base portion117integrally disposed within and extending through the sole of a footwear article109with the first and second base attachment points119disposed on respective external sides of the footwear article109.

In some embodiments, the rigid foot structure110further comprises an inflatable structure121. In some embodiments, an inflatable structure121is positioned at the sole of a foot of a user and configured to evenly spread a load on a surface generated while the user is walking on the surface. In some embodiments, the rigid shin structure further comprises an inflatable structure151.

Accordingly, the inflatable actuator140can provide a moment about the ankle104of the user101due to the difference in expansion of the bladder segments210between the front and rear portions. For example, inflation of the actuator140can generate a moment that forces the shin structure150toward the shin108of the user, and a moment that generates plantar flexion of the foot103. In other words, the shin structure150engaging the shin108opposes the actuator140such that a rotation generated by the actuator140during inflation results in rotation of the foot103.

Although a generally C-shaped inflatable actuator140is illustrated in the example embodiment ofFIG. 1, in further embodiments as discussed in detail herein, other suitable actuators and actuator configurations can be used. For example, in one embodiment, an actuator140can be powered in other suitable ways including via a motor, or the like. Additionally, in another example, an actuator can include elongated segments positioned along the length of the shin108at the front of the foot103, which can be configured to expand and curl lengthwise to generate a moment that causes plantar flexion of the foot103. In a further example, an actuator140can completely surround the foot103. Accordingly, it should be clear that the example actuator140illustrated in this disclosure should not be construed to be limiting on the many alternative actuators that are within the scope and spirit of the present invention.

FIG. 2illustrates an exoskeleton system200that comprises a first and second lower-leg exoskeleton100that are operably connected to an actuation system210that includes a pneumatic system220and a control system230. The pneumatic system220is shown being operably connected to the actuators140and to the control system230. The control system230is illustrated being operably connected to one or more portions of the lower-leg exoskeletons100and to the pneumatic system220.

In various embodiments, the pneumatic system220can be configured to inflate and/or deflate the actuators140with a fluid. For example, in one embodiment, the pneumatic system220can only be configured to actively inflate the actuators140to cause expansion of the actuators140and plantar flexion, where deflation can be generated during contact with the ground during walking and where natural dorsiflexion occurs. In another embodiment, the pneumatic system220can be configured to actively inflate the actuators140to cause expansion of the actuators140and plantar flexion, and can actively generate dorsiflexion by actively evacuating fluid from the actuators140and/or by generating release of fluid from the actuators140.

Alternatively, in some embodiments, the actuators can be configured oppositely. For example, inflation of the actuator140can cause dorsiflexion of the foot103and deflation can cause or be caused by plantar flexion of the foot103. Additionally, although the example of a pneumatic system220is provided, which actuates the actuators140via a gas fluid (e.g., air), in further embodiments, the actuators140can operate via any suitable fluid, including water, oil, or the like.

In some embodiments, inflatable actuators can be positioned in other locations in addition to or alternatively to the inflatable actuator140illustrated inFIGS. 1 and 2. For example, one or more actuators can be positioned about the sole of the foot103, at the heel107, or the like. Such additional or alternative actuators can be configured to generate various types of movement of the foot103, including inversion, eversion, plantar flexion, dorsiflexion, flexion of a toe, extension of a toe, and the like. Additionally, various suitable portions of a lower-leg exoskeleton100can comprise inflatable support structures as discussed herein.

The control system230can be associated with various suitable portions of the lower-leg exoskeleton100and can be associated with one or more suitable sensors. For example, sensors can determine a position, movement, rotation or orientation of the foot103and/or portion of the lower-leg exoskeleton100. Additionally, and alternatively, such sensors can determine an inflation state of an actuator140, a pressure associated with an actuator140, or the like. Additionally, and alternatively, such sensors can measure body and/or environmental conditions such as temperature, moisture, salinity, blood pressure, oxygen saturation, muscle tension, and the like.

In various embodiments, the control system230can sense conditions associated with the lower-leg exoskeletons100and inflate and/or deflate the actuators140in response. In some embodiments, the control system230can generate a walking gait for a user101of the lower-leg exoskeletons100by selective inflation and/or deflation of the actuators140. In other embodiments, the control system230can identify and support movements of a user101associated with the lower-leg exoskeletons100. For example, the control system230can determine that a user101is lifting a heavy object and provide enhancing support to the user101in lifting the object by selective inflation and/or deflation of the actuators140.

Accordingly, the present example embodiment shown inFIGS. 1 and 2should not be construed to be limiting on the wide variety of alternative embodiments that are within the scope and spirit of the present invention. For example, in some embodiments, the control system230can comprise sensors such as ground reaction force sensors embedded in the sole of the shoe along with pressure and angle sensors to measure the effort of the actuation. Muscle activation sensors can also be integrated into footwear to allow for feedback control by the control system230.

FIG. 3is a block diagram of an embodiment of an exoskeleton system200that includes a control system210that is operably connected to a pneumatic system220. The control system210comprises a processor311, a memory312, and at least one sensor313. A plurality of actuators140can be operably coupled to the pneumatic system220via respective pneumatic lines330. The plurality of actuators140include pairs of shoulder-actuators140S, elbow-actuators140E, knee-actuators140, and ankle-actuators140A that are positioned on the right and left side of a body101. For example, as discussed above, the example exomuscle system100D shown inFIG. 3can be part of top and/or bottom suits with the actuators140positioned on respective parts of the body101as discussed herein. For example, the shoulder-actuators140S can be positioned on left and right shoulders; elbow-actuators140E can be positioned on left and right elbows; knee-actuators140K on our about the knee; and ankle actuators140A can be positioned on or about the ankle104.

In various embodiments, the example system ofFIG. 3can be configured to move and/or enhance movement of the user101wearing the exoskeleton system200. For example, the control system210can provide instructions to the pneumatic system220that can selectively inflate and/or deflate the actuators140. Such selective inflation and/or deflation of the actuators140can move the body to generate and/or augment body motions such as walking, running, jumping, climbing, lifting, throwing, squatting, or the like.

In some embodiments, such movements can be controlled and/or programmed by the user101that is wearing the exomuscle system100D or by another person. Movements can be controlled in real-time by a controller, joystick or thought control. Additionally, various movements can be pre-preprogrammed and selectively triggered (e.g., walk forward, sit, crouch) instead of being completely controlled. In some embodiments, movements can be controlled by generalized instructions (e.g. walk from point A to point B, pick up box from shelf A and move to shelf B).

In further embodiments, the exomuscle system100D can be controlled by movement of the user101. For example, the control system210can sense that the user101is walking and carrying a load and can provide a powered assist to the user101via the actuators140to reduce the exertion associated with the load and walking. Accordingly, in various embodiments, the exomuscle system100D can react automatically without direct user interaction.

Some example functions, configurations and uses are described and shown in U.S. Provisional Application 63/030,586, filed May 27, 2020, entitled “POWERED DEVICE FOR IMPROVED USER MOBILITY AND MEDICAL TREATMENT” with attorney docket number 0110496-010PR0 and U.S. Provisional Application 63/058,825, filed Jul. 30, 2020, entitled “POWERED DEVICE TO BENEFIT A WEARER DURING TACTICAL APPLICATIONS” with attorney docket number 0110496-011PR0. As discussed above, the present application claims priority to these provisional applications, and these provisional applications are incorporated herein by reference in their entirety and for all purposes.

In some embodiments, the sensors313can include any suitable type of sensor, and the sensors313can be located at a central location or can be distributed about the exomuscle system200. For example, in some embodiments, the system200can comprise a plurality of accelerometers, force sensors, position sensors, and the like, at various suitable positions, including at the actuators140or any other body location. In some embodiments, the system200can include a global positioning system (GPS), camera, range sensing system, environmental sensors, or the like.

The pneumatic system220can comprise any suitable device or system that is operable to inflate and/or deflate the actuators140. For example, in one embodiment, the pneumatic module can comprise a diaphragm compressor as disclosed in related patent application Ser. No. 14/577,817 filed Dec. 19, 2014.

Turning toFIGS. 4aand 4b, one example embodiment of an actuator140is illustrated that comprises a fluid-impermeable member410disposed between a pair of opposing interfaces420that define first and second ends141,142of the actuator140. The fluid-impermeable member410can define first and second opposing ends411,412and opposing sidewalls413. The fluid-impermeable member410can further define a fluid cavity415, which can be configured to hold a fluid and be inflated and deflated via fluid being removed from and introduced to the cavity415as discussed herein. As shown in the example ofFIGS. 4aand 4b, in some embodiments, the interfaces420can comprise planar plates, with the fluid-impermeable member410being configured to inflate via fluid in the fluid cavity415, which can cause the first end411of the fluid-impermeable member410to expand and elongate more than the second end412of the fluid-impermeable member410.

As discussed herein, interfaces420in some examples can be rigid, semi-rigid, flexible or some combination thereof. In some embodiments, the fluid-impermeable member410may comprise, consist essentially of or consist of inextensible or semi-extensible membrane materials with fluid-impermeable or near-impermeable qualities, such as coated fabrics or a urethane film supported by a fabric, or the like. As discussed in more detail herein, the fluid-impermeable member410can comprise a flexible, yet inextensible, sheet material such as a fabric.

For example, in some embodiments, the impermeable member410can comprise a flexible sheet material such as woven nylon, rubber, polychloroprene, a plastic, latex, a fabric, or the like. Accordingly, in some embodiments, the impermeable member410can be made of a planar material that is substantially inextensible along one or more plane axes of the planar material while being flexible in other directions. For example,FIG. 5illustrates a side view of a planar material500(e.g., a fabric) that is substantially inextensible along axis X that is coincident with the plane of the material500, yet flexible in other directions, including axis Z. In the example ofFIG. 5, the material500is shown flexing upward and downward along axis Z while being inextensible along axis X. In various embodiments, the material500can also be inextensible along an axis Y (not shown) that is also coincident with the plane of the material500like axis X and perpendicular to axis X.FIGS. 13a, 13band 13calso illustrates an example of an impermeable member410that can comprise an inextensible material and how such a material can affect the operation of a fluidic actuator140.

In some embodiments, the impermeable member410can be made of a non-planar woven material that is inextensible along one or more axes of the material. For example, in one embodiment the impermeable member410can comprise a woven fabric tube or loop. Woven fabric material can provide inextensibility along the length of the impermeable member410and in the circumferential direction.

In various embodiments, the impermeable member410can develop its resulting force by using a constrained internal surface length and/or external surface length that are a constrained distance away from each other (e.g., due to an inextensible material as discussed above). In some examples, such a design can allow the actuator140to contract on the impermeable member410, but when pressurized to a certain threshold, the impermeable member410can direct the forces axially by pressing on the interfaces420of the leg actuator unit110because there is no ability for the impermeable member410to expand further in volume otherwise due to being unable to extend its length past a maximum length defined by the body of the impermeable member410.

For example, the impermeable member410can comprise a substantially inextensible textile envelope that defines a fluid cavity415that is made fluid-impermeable by a fluid-impermeable bladder contained in the substantially inextensible textile envelope and/or a fluid-impermeable structure incorporated into the substantially inextensible textile envelope. The substantially inextensible textile envelope can have a predetermined geometry and a non-linear equilibrium state at a displacement that provides a mechanical stop upon pressurization of the chamber to prevent excessive displacement of the substantially inextensible textile actuator.

In some embodiments, the impermeable member410can include an envelope that consists or consists essentially of inextensible textiles (e.g., inextensible knits, woven, non-woven, etc.) that can prescribe various suitable movements as discussed herein. Inextensible impermeable member410can be designed with specific equilibrium states (e.g., end states or shapes where they are stable despite increasing pressure), pressure/stiffness ratios, and motion paths. Inextensible textile impermeable member410in some examples can be configured accurately delivering high forces because inextensible materials can allow greater control over directionality of the forces.

Accordingly, some embodiments of inextensible textile impermeable member410can have a pre-determined geometry that produces displacement mostly via a change in the geometry between the uninflated shape and the pre-determined geometry of its equilibrium state (e.g., fully inflated shape) due to displacement of the textile envelope rather than via stretching of the textile envelope during a relative increase in pressure inside the chamber; in various embodiments, this can be achieved by using inextensible materials in the construction of the envelope of the impermeable member410. As discussed herein, in some examples “inextensible” or “substantially inextensible” can be defined as expansion by no more than 10%, no more than 5%, or no more than 1% in one or more direction.

Returning to the example ofFIG. 4, in some examples, the fluid cavity415can be defined exclusively by the fluid-impermeable member410, or the fluid cavity415can be defined by a combination of the interface components420and fluid-impermeable member410. Accordingly, in various embodiments, the interfaces420can comprise a material that is fluid-impermeable or near fluid-impermeable to store fluid within the fluid cavity415. In various embodiments, the fluid-impermeable member410can comprise a bladder. The quality of impermeability of the fluid cavity415or materials that define the fluid cavity415can refer to the ability to contain a fluid in such a manner as to be able to produce a useful output, (e.g., as a force, position, or contained volume), which can be through the ability of the fluid-impermeable member410to contain the fluid at a desired pressure. When the fluid-impermeable member410is a closed volume, in various embodiments, there will be either no leakage or a very slow leakage of fluid.

Forces, moments and position changes can be produced by changing the pressure and volume of fluid disposed within the fluid cavity415of the fluidic actuator140. The pressure of fluid within the fluid cavity415of fluidic actuator140can be negative, neutral or positive relative to the surrounding environment. The term “pressurized” can include any of these possible fluidic pressure states. In some embodiments, fluid introduced to and/or removed from the fluid cavity415can comprise gases such as air, liquid, liquefied gas, slurries, liquids containing solids, molten solids, or the like.

As discussed herein such fluidic actuators140can be used in a variety of applications, some of which may include but are not limited to controlling positioning between two or more bodies, producing force between two or more bodies, creating a moment about an axis or axes, or propelling a single body, where a body is generalized to any physical object/thing that may be composed of a flexible, semi-rigid, or rigid single body or multiple of such bodies interconnected. For example, elements of a robotic exoskeleton200can be coupled to the interfaces420, and expansion of the fluid cavity415via fluid can apply force the interfaces420. Such a force can move the body101of a user such as the joint of the ankle104, as discussed herein.

The fluidic actuator may apply forces or moments with a specific or generalized direction or directions, whether through the interfaces420themselves, through interaction with the fluid-impermeable member410itself, or any combination therein. These force and positioning abilities can direct application for use in body-worn exoskeleton devices200, such as those that can assist with flexion and/or extension at a human body joint, including the ankle, knee, elbow, hip, neck, and the like.

One or more interfaces420can provide various suitable functions or combinations of functions in some examples, including but not limited to acting as a connection point for the actuator140to another body; acting as a fluid manifold between the impermeable member410(e.g., a bladder) and another fluidic element such as a valve; acting as a manipulator of the impermeable member410to change the geometry of the impermeable member410; and participating as an element through which the force of the impermeable member410can be applied or which can guide the application of that force (such as in direction or magnitude).

Some configurations of a fluidic actuator140have two interface components420as shown in the example ofFIGS. 4aand 4b, but further examples can include any suitable plurality of interfaces420, a single interface420, or interfaces can be specifically absent from a fluidic actuator140. Some configurations of an actuator can have interfaces420located at opposing ends141,142of the fluidic actuator140, but these interfaces420can be located anywhere on the fluidic actuator140in further examples, including but not limited to at the ends, sides, and circumferentially disposed on or about the actuator140. An interface420can be made of a number of different or combination of suitable materials (e.g., polymer, metal, wood, or the like) and can have various suitable geometries. In some embodiments, an interface420can comprise a component that is an integral part of a fluidic actuator140, but may also be shared and integral to other bodies in some examples, including but not limited to other fluidic actuators, structures, exoskeletons, and the like.

One or more interfaces420can take on any suitable geometry. In some embodiments, parameters that influence the geometry of an interface420can include but are not limited to structural properties of the interface420(e.g., strength, stiffness, weight and appearance); any internal or external geometries of the interface that may be required for the interface420to act as a fluid manifold; any constraints such that the interface420can interact with a human user101or other body; an anticipated amount of force applied by or to the interface420during operation; a desired direction or directions of force application by one or more interface420; features that promote the positioning and/or connection of the actuator140to another body or bodies; features of the interface420that support the manufacturability of the impermeable member410, and the like.

In some embodiments, the geometry of one or more interfaces420can be configured to correspond to the shape of portions of the human body, which can be desirable to accommodate the application of forces and moments about various joints. For example,FIGS. 6aand 6billustrate an example of an actuator140having first interface420with a curved cutout portion600defined by an edge of the interface420A, which can be desirable to avoid undesirable physical interaction with the shin of the leg102of the user101when the actuator140acts as part of an exoskeleton100that sits between the foot103and lower leg102, as shown in the example ofFIGS. 6aand 6b. Specifically, as shown inFIG. 6b, the curved cutout portion600of the interface420A can comprise a concave rounded profile that corresponds to the generally rounded portions of the leg102of the user101, where the interface420A can engage. For the purpose of clarity, the cross-sectional perspective ofFIG. 6billustrates the interface420A spaced apart from the leg102of the user101, but it should be clear that the interface420A can engage the leg102of the user101.

In further embodiments, one or more interfaces420of an actuator140can be configured to correspond with the shape of various suitable portions of the body of a user101. For example,FIG. 6aillustrate an example of an actuator140coupled about the ankle140of a user101with a first and second interface420A,420B respectively engaging the foot103and lower portion of the leg102and respectively coupled to a foot portion620and lower leg portion650of an exoskeleton100. In various embodiments, the second interface420B can be shaped to correspond to the top of the foot103where the interface420B is engaging. In further embodiments, one or more interfaces420can be configured to correspond to the shape of toe(s), foot, lower leg, upper leg, torso, finger(s), wrist, forearm, upper arm, shoulder, neck, head, and the like.

The shape and size of one or more interfaces420can also be designed to provide a specific desired application force based on the fluidic pressure and contact surface area between the interface420and another element. The geometry of an interface420can also include features to promote the longevity of a fluidic actuator140, which may include but are not limited to features that reduce failures within or of the impermeable member410(e.g., a bladder), interface, a bladder-to-interface connection, or the like. Some example embodiments of these interface features can include chamfers, fillets, rounded edges, and the elimination of any sharp corners, edges, burrs, or abrupt transitions in the interface geometry at portions the impermeable member410contacts one or more interface420and/or is connected to the one or more interface420, which may reduce failure of the impermeable member410during pressurization due to puncture or tearing of the material of the impermeable member410. Other example embodiments can include the addition of ribs, combinations of different strength and stiff materials, and other features that may be configured to reduce the likelihood of an interface420cracking or breaking when force is applied to the interface420, whether from the fluidic actuator140itself, such as during pressurization, or when force is applied to another external body.

Various embodiments can be configured for manufacturing. For example,FIG. 7illustrates an example actuator140having a first and second interface420in accordance with one embodiment720that comprise an interface plate722with a lip724extending around the perimeter of the interface plate722that defines an interface cavity726. Such a configuration of the interfaces420can allow for welding of a fluid-impermeable membrane material740to external sidewalls of the interface720as shown in the example ofFIG. 7to generate the fluid-impermeable member410of the actuator140. Such a configuration of an interface420having a lip724and interface cavity can be considered to be a planar interface420in various embodiments.

For example,FIG. 7illustrates an actuator140having three welds750that couple the fluid-impermeable membrane material740to external sidewalls of the interface720to generate the fluid-impermeable member410and fluid cavity415defined by the interfaces420and membrane material740.FIG. 7further illustrates a fourth weld being generated at a weld location730via a welding tool710having a first portion712configured to be disposed within the interface cavity726. A second portion714of the welding tool710is shown disposed facing an external face of the membrane material740with a portion of the lip724of the interface720and portion of the membrane material740between the first and second portions712,714of the welding tool710that defines the weld location730. Energy735an can be applied by the welding tool710at the weld location730, which can generate a weld750that couples the fluid-impermeable membrane material740to lip722of the interface720. Various suitable types of welding can be used, including ultrasonic welding, inductive welding, and the like.

One example of such an embodiment can comprise interface plates722with an extended lip724around the perimeter of the plates722which allows for the ability to use the welding machine710to weld a membrane material740circumferentially around the interface720(see e.g., example ofFIGS. 17aand 17b). Such a manufacturing technique can allow in some examples for a fluidic actuator140to be made at a mass manufacturable scale, where the fluidic actuator140comprises two opposing interfaces420surrounded by a fluid-impermeable membrane740to generate a fluid-impermeable member410and fluid cavity415of the actuator140.

Another embodiment of geometry of an interface420that can provide for mass-manufacturing can include the use of features integrated into the interface420that mate with features in a membrane material740, which can increase ease of locating the membrane material740relative to the interface420and/or of holding the membrane material740in place, which can facilitate welding of the membrane material740to one or more interface420. One example of such mating features is screws that are over-molded into an injection molded plastic interface420that can match locating holes in a fluid-impermeable coated fabric that acts as the membrane material740. Another embodiment of an interface420can include interface geometry that allows for membrane material740to pass through the interface420, which can be used to divide the fluid-impermissible member410(e.g., a bladder) into different useful volumes, which can generate a fluid-impermissible member410having a plurality of fluid cavities415.

An interface420can be made of various suitable types of materials including but not limited to metals like aluminum and steels, plastics like polycarbonate, engineered polyurethane and injection molded thermoplastic polyurethanes (TPU), composites like carbon fiber, rubbers, woods, and other materials as well as any combination thereof that may be rigid, semi-rigid or flexible. Some examples of combinations of materials include but are not limited to materials joined by mechanical and chemical bonds, such as a plastic over-molded with a rubber, metal glued to plastic with an adhesive, or metal fixed to a carbon fiber plate with screws. Material selection can be dictated in some embodiments by the amount of force application expected during use or manufacturing, as well as other requirements such as stiffness/flexibility, weight, ease of manufacturability, cost, accessibility, time to acquire, biocompatibility, durability, ability to undergo decontamination, or ability to bond with the fluidic actuator directly. These different combinations of materials can be used in some examples to create variable stiffnesses, strengths, frictions, colors, etc., throughout the interface420, which in turn may have benefits including the ability to change the interface geometry when the fluidic actuator140is pressurized or where a pre-determined failure of a weaker material within the interface420could be utilized as a safety measure against over-pressurization.

Additionally, in various examples, one or more interfaces420can also be used as a manifold to allow for the control of fluidic flow into and out of the fluid cavity415of an actuator140such that the fluid cavity415of the fluid-impermissible member410can be pressurized and depressurized. Embodiments can include but are not limited to one or more fixed open pathways through the interface420such as an inlet and outlet nozzle or through-hole with a face seal, valves integrated into the plate itself, as well as other integrations of fluidic components or pathways. Such fluidic pathways within a manifold may be created in various suitable ways including via additive manufacturing/3D printing or material machining methods which in some examples may require more than one body joined and sealed together to create one or more fluidic pathways. Some example embodiments of valves that can be incorporated into the interface420or manifold of an interface420can include check valves, one-way valves, poppet valves, proportional valves, etc., which may be self-regulating and/or externally controlled through manual, mechanical, electromechanical or other suitable methods. Other fluidic components that can be incorporated into an interface420in accordance with further embodiments can include silencers and/or diffusers which may assist with noise reduction and fluidic fittings (e.g., push-to-connect fittings) that allow for external connections.

For example,FIG. 18illustrates an embodiment of a fluidic actuator140having a first and second interface420A,420B, where the first interface420A comprises an inlet nozzle1830that defines an inlet channel1835and where the second interface comprises an outlet nozzle1850that defines and outlet channel1855. The outlet nozzle1850can comprise an outlet valve1860. In various embodiments, the inlet and outlet nozzles1830,1850can be configured to introduce and remove fluid from the fluid chamber415, which can cause the actuator140to expand and contract as discussed herein. For example, the inlet nozzle1830can be coupled to a pneumatic system220via one or more pneumatic lines330(see, e.g.,FIGS. 2 and 3), which can be configured to introduce fluid into the fluid chamber415of the actuator140via the inlet nozzle1830.

Fluid within the fluid chamber415of the actuator140can be removed or allowed to escape via the outlet nozzle1850. For example, in some embodiments, the outlet valve1860can be opened (e.g., via a control system210and/or pneumatic system220) which can allow fluid within the fluid chamber415of the actuator140to leave the fluid chamber415. In some embodiments, fluid leaving the fluid chamber415via the outlet nozzle can be vented to the external environment or can be vented to a storage location, to another pneumatic actuator140, to a pneumatic system220, one or more pneumatic lines330or the like.

As shown in the example ofFIG. 18, the inlet and outlet nozzles1830,1850can extend from the interfaces420A,420B toward opposing sides of the actuator140or external faces of the respective interfaces420. In some embodiments, the inlet and outlet nozzles1830,1850can be an integral part of the interfaces420such as being manufactured as part of the interfaces via additive manufacturing, injection molding, milling, or the like. Additionally, while the example ofFIG. 18illustrates the inlet and outlet nozzles1830,1850respectively being part of the first and second interfaces420A,420B, in some embodiments, one interface420can comprise both the inlet and outlet nozzles1830,1850with another interface being without the inlet or outlet nozzles1830,1850. In further embodiments, an actuator can have only a single nozzle, which provides for fluid both leaving and being introduced to the fluid chamber415.

One embodiment of a manifold of an interface420can include an interface420that allows membrane material740(e.g., portion of a bladder) to travel or sit through the interface420, where a manifold of the interface420is configured for pinching off some or all of the membrane material740, forming separate fluid cavities415within a fluid-impermeable member410where flow is either completely or partially interrupted between the separate fluid cavities415. In various embodiments a manifold of an interface420can generate one or more fluid cavities415within a fluid-impermeable member410(e.g., within a bladder). Such pinching off of the fluid-impermeable member410can be created in various suitable ways including mechanical, electromechanical, pneumatic, hydraulic, magnetic, or the like. One example embodiment can include an interface420incorporating two mechanical jaws operated by a solenoid, where activating the solenoid closes the jaws onto a bladder, thus creating separate fluid chambers415in the bladder. If the jaws shut completely across the membrane of the bladder, then flow can be completely interrupted between the newly formed fluid chambers415. If such fluid chambers415are not shut completely or are shut completely but in such a way that the fluid chambers415are not fully separate, then flow of fluid between the chambers415can be more restricted than previously between the newly formed chambers415. In some examples, this can allow for the dynamic or static creation of chambers415with different pressurizations, where one chamber415can be held at a constant volume and/or pressure while another is actively being pressurized and changing volume. Various examples can generate chambers415that are pressurizing and changing volume at different rates, and various examples can generate chambers415that are both statically holding a constant volume and/or pressure.

FIGS. 19aand 19billustrate two configurations of a fluidic actuator140coupled to the leg102and foot103of a user101configured to cause rotation about the ankle of104of the user101. As shown in the example ofFIGS. 19aand 19bthe actuator140can comprise a fluid impermeable member410defined at least in part by a membrane material740. The fluid impermeable member410can define a fluid chamber415that can be configured to be separated into a first and second sub-chamber415A,415B via a pinching system1900that comprises a pinching mechanism1910rotatably coupled to a bar1920via a hinge1930. The pinching mechanism1910can be configured to pinch a central portion of the fluid impermeable member410to partially or completely separate the fluid chamber415into the first and second sub-chambers415A,415B. As discussed herein, such a pinching system1910can comprise various suitable structures such as a pair of jaws, pair of bars, a pinching aperture, or the like.

FIG. 19aillustrates a first configuration where the first and second sub-chambers415A,415B are pressurized andFIG. 19billustrates a second configuration where the first sub-chamber415A remains pressurized while the second sub-chamber415B is depressurized or at least pressurized less than the first sub-chamber415A. For example, an outlet valve1860of the second interface420B can open to allow fluid in the second sub-chamber415B to be vented from the second sub-chamber415B while the first sub-chamber415A can remain fully or partially pressurized via complete or partial1910pinching between the first and second sub-chambers415A,415B. As shown inFIG. 19apressurization of both the first and second sub-chambers415A,415B can generate an angle between the leg102and foot103of the user101to be larger than an angle between the leg102and foot103of the user101when the second sub-chamber415B is fully or partially depressurized as shown inFIG. 19b.

Having multiple chambers415can be useful in some embodiments when considering the stroke of a fluidic actuator140and the usage of the pressurized fluid within one or more of the chambers415to create that stroke. One example embodiment can include a fluidic actuator140with an interface240across a mid-plane of the actuator140that can pinch off a bladder of the actuator completely to generate two or more chambers415. Then, a manifold interface to one of the chambers415can allow for the pressure and/or volume to change in that chamber415, while the other chamber415is held constant in volume. Instead of having to empty and refill the entire bladder to achieve a desired range of motion (which can be a subset of the entire range of motion of the actuator410), only the smaller chamber can be emptied and refilled with pressurized fluid in some examples.

One or more interfaces420, in some embodiments, can be used to provide accessibility and the ability for sensing of the state of the fluid-impermissible member410(e.g., a bladder), the state of pressurized fluid within one or more fluid chamber415and/or the state of the interface420itself including but not limited to fluidic pressure, volumetric flow rate of fluid into and out of the fluid-impermissible member410, temperature and/or volume of fluid, mechanical strain of the fluid-impermissible member410, total volume of the fluid-impermissible member410, force applied by the fluid-impermissible member410and/or interface420to another body, mechanical strain on the interface420, vibration of the fluid-impermissible member410and/or interface420, and various other characteristics.

Various suitable sensors can be used to sense these characteristics including but not limited to pressure sensors, force gauges, strain gauges, temperature sensors, accelerometers, flowmeters and other suitable devices. In some embodiments, sensors can be integrated into flow path through the interface420(e.g., temperature sensor to measure flow temperature or anemometer to measure flow velocity), adjacent to the flow path, sometimes with an additional dead volume (e.g., for pressure measurements), on the surface of the interface420, internal to the interface420, through the interface420, or may extend away from the interface420to measure the state of the fluid-impermissible member410, either internal or external of the fluid-impermissible member410, or any combination thereof.

For example,FIG. 8illustrates an example actuator140having a first and second interface420A,420B that each comprise an interface plate722with a lip724extending around the perimeter of the interface plate722that defines an interface cavity726. A fluid-impermeable membrane material740is coupled to external sidewalls of the interfaces720via welds750(see also examples ofFIGS. 17aand 17b), which generates the fluid-impermeable member410and fluid cavity415defined by the interfaces420and membrane material740.

In this example embodiment, the first interface420A comprises a pressure sensor unit810disposed in the interface cavity726that includes a body812defining a dead volume chamber814, which communicates with fluid chamber415of the fluid impermissible member410via pressure-sensor port816defined by the interface plate722of the first interface420A. A first pressure sensor818within the dead volume chamber814can be configured to sense the pressure of fluid within the fluid chamber415via the pressure-sensor port816.

The first interface420A further comprises a flow port830defined by the interface plate722of the first interface420A. As discussed herein, fluid can be introduced to and removed from the fluid chamber415via the flow port830, which can cause the actuator to expand and contract. A temperature sensor835can be disposed within the flow port830, which can be configured to sense the temperature of fluid entering and leaving the fluid chamber415, the temperature of fluid within the fluid chamber415, and the like.

The second interface420B can comprise a second pressure sensor840that can be disposed on the interface plate722of the second interface420B with the second pressure sensor840extending within the fluid chamber415and configured to sense the pressure of fluid within the fluid chamber415. The second interface420B can further comprise a strain gauge845on the interface plate722within the interface cavity726of the second interface420B. The strain gauge845can be configured to sense strain associated with the second interface420B.

In various embodiments, the sensors818,835,840,845can be operably connected to a control system210of an exoskeleton system200, with data from the sensors818,835,840,845being used to control the exoskeleton system200as discussed herein. The example embodiment ofFIG. 8is only provided for purposes of illustration and should not be construed to be limiting on the wide variety of additional embodiments that are within the scope and spirit of the present disclosure. For example, sensors of various suitable types can be disposed in various suitable locations on, in, or about an actuator140.

As shown in the example ofFIG. 9, one example embodiment of sensor integration into the interface420to measure force output includes a load cell950integrated into an interface420of a fluidic actuator140for an ankle exoskeleton100to measure the force application of the fluidic actuator140through an exoskeleton foot structure620into the ground. For example,FIG. 9illustrates a fluidic actuator140coupled about an ankle104of a user101having a first and second interface420A,420B with the second interface420B having a load cell950coupled between the second interface420B and the exoskeleton foot structure620. Another example embodiment of sensor integration into an interface420to measure a state of the interface420itself includes a strain gauge incorporated with a ring (e.g., plastic ring) that encircles the fluid impermeable member410(e.g., a bladder) to measure the strain on the ring interface itself.

In some embodiments, interfaces420can comprise integrated features to help with attachment between the fluidic actuator140and other bodies such as parts of a user101(e.g., leg102, foot103, and the like), parts of an exoskeleton100(e.g., structures120,150,620,650ofFIGS. 1 and 6). In some examples, such parts of an exoskeleton100can be referred to as retaining bodies. Various features, in some examples, can be configured to locate the fluidic actuator140relative to a retaining body. Such features can include but are not limited to molded inserts, snap features, sliding mechanisms, slots, threaded holes, through holes, pins, bosses, debosses, lips, detents, threaded inserts, over-molded screws, magnets, spring-loaded features and the like. When used in conjunction with an exoskeleton100in some embodiments, these attachment features of an interface420can allow for quick connection or disconnection from an exoskeleton structure (e.g., structures120,150,620,650ofFIGS. 1 and 6), which can be useful in various embodiments, including when a fluidic actuator140fails and needs to be replaced, or the like. One example embodiment of such a quick connection/disconnection feature is a female sliding feature on one or more fluidic actuator interfaces420that mates with a male feature on an exoskeleton structure (e.g., structures120,150,620,650ofFIGS. 1 and 6), allowing for the actuator140to be easily slid into and out of the system. Such features can also be used to create more or less secure attachments of the fluidic actuator140with a retaining body like an exoskeleton system. One example embodiment of this is the use of molded inserts that mate with holes in an exoskeleton structure (e.g., structures120,150,620,650ofFIGS. 1 and 6), allowing for locking nuts to be used to secure the fluidic actuator140to the exoskeleton structure.

While some embodiments of interfaces420can be directly bonded to or otherwise in contact with a fluid-impermeable member410(e.g., a bladder, membrane material740, or the like) to allow for interaction with or by the fluidic actuator140, in further embodiments other structures can interact with the interface420. Such structures can be rigid, semi-rigid, flexible, or the like. Such structures may also act to provide for attachment to one or more retaining bodies, which may or may not include one or more retaining bodies with which the interface420also interacts. Such structures may also provide support to the fluidic actuator140to achieve various objectives.

In one embodiment, the support structure can be used to strengthen a bond between a fluid-impermeable member410(e.g., a bladder, membrane material740, or the like) and the support structure; between a fluid-impermeable member410and an interface420, or any combination and multiple thereof. For example, one embodiment can include a membrane material740bonded circumferentially around the sides of an interface420(e.g., welded as shown inFIGS. 7, 8, 17aand17b), and an additional structural element can be used to support that bonding by constraining free membrane material740surrounding a bond between the membrane material740and interface420. This may be done in such a way, in some examples, to constrain the membrane material740during pressurization such that the membrane material740adjacent to the bond does not reach a critical peel angle with the bonded faces of the membrane material740and interface420. Such a critical peel angle can lead to the bond reaching a critical peel state, where the normal component of the tension force, where normal is relative to the bonded faces of the membrane material740and interface420, within the material adjacent to the bond reaches a magnitude that causes the bond to fail in peel.

One example case of this can be where membrane material740adjacent to a bond is perpendicular to the bond faces of the membrane material740and interface420, leading to some or all of the tension force within the membrane material740contributing directly to peel and subsequent failure of the bond at a certain magnitude of tension. Avoiding such a critical angle and subsequent critical peel state can maintain the bond primarily in a shear state where less failure of the bond can be prone to occur, with some exceptions where the bonding method may be weaker in shear, such as with the use of two flat parallel magnetic faces. It should be noted that avoiding this critical peel state and maintaining bonds primarily in a shear state, and in some examples ideally with all bonds occurring as lap welds and all materials nearest the bonds remaining close to parallel with the bond faces, between the interface and the fluid-impermeable member410, as well as within the construction of the fluid-impermeable member410itself, may be advantageous not only at preventing the failure of those bonds, but may also have an advantage that any coated fabrics being used as a fluid-impermeable membrane material740and which participate in any of these bonds may also be loaded primarily in shear nearest the bond.

For example, in various embodiments, the location of shear/lap welds (see e.g.,FIG. 14b) along with the geometry of the fluid-impermeable member410, constraints, and the like, can be configured such that the tension in the membrane material740nearest to the weld never exceeds 45 degrees from parallel to the weld such as when the fluid chamber415is at a maximum inflation state. Further embodiments can be configured such that the membrane material740nearest to shear/lap welds will not exceed 40, 35, 30, 25, 20, 15, 10 or 5 degrees from parallel to the weld.

This can be desirable in some embodiments because some coated fabrics with a fluid-impermeable property can become fluid permeable if the coating and fabric separate, which can occur in some examples from delamination during peel. When a coated fabric participates in a bond, in some examples it can be the coating that is actually directly participating in the bond, then it can be possible for the bond to never reach a critical peel state but for the coating and fabric to still delaminate, creating permeability and failure of the fluid-impermeable member410. This can be mitigated in various embodiments where the bond is held mainly in shear, as the likelihood of delamination between the coating and the fabric can be reduced in such a loading case.

In some example embodiments, a structural bond support element can take the form of a rigid plate that nests atop the interface420and whose sides overlap past the perimeter of the interface420, such that when a membrane material740is bonded around that perimeter (see e.g., example ofFIGS. 17aand 17b) to form the fluid-impermeable member410, the membrane material740nearest the bonds along the sides of the interface420are captured and prevented from reaching the critical peel state. In other embodiments, such structural support element can comprise a feature in a retaining body by which a bladder interface is captured. For example, in one embodiment, such feature could be a recess within the retaining body, such as an exoskeleton device100, which captures the interface420of the fluidic actuator140in such a way as to create a bond-supporting material constraint.

FIGS. 10aand 10billustrate an example of a support element1000that is configured to couple about and support welds750between a membrane material740and sidewalls of an interface420. The support element can comprise a central unit1010configured to reside within the interface cavity726of the interface420with a rim1020on the edges of the support element defining a coupling slot1030along with the central unit1010. The lip724of the interface420along with the welds750and a portion of the membrane material740can be configured to be coupled within the coupling slot1030, which can support the welds750as discussed herein. It should be noted that while the example ofFIG. 10aillustrates elements spaced apart for clarity, in various embodiments, the lip724, welds750and membrane material740, can engage internal faces of the coupling slot1030defined by the central unit1010and rim1020, which can provide a secure friction fit that supports the welds750as discussed herein.

As shown in the example ofFIG. 10b, where the impermeable member410is inflated with pressurized fluid, the membrane material740can expand outward compared to the flat configuration ofFIG. 10a, and a portion of the membrane material740proximate to the weld750can engage an end1022of the rim1020of the support element1000, which can allow the portion of the membrane material740at the weld750to remain parallel to the face of external face of the interface420, which can prevent non-shear forces on the weld750, which could result in failure of the weld750.

For example,FIG. 10cillustrates an example where a weld750has failed with a portion of membrane material740decoupling from the interface420. In contrast toFIG. 10b, where a support element1000supports the weld750, in the example ofFIG. 10c, the inflation of the impermeable member410can cause the membrane material740at the weld750to assume a critical peel state, which can cause the weld750to fail due to peeling, delaminating or other separation of the membrane material740from the sidewall of the interface420.

Other embodiments of a structural bond support element can include but are not limited to an element that has a region where the membrane material740is purposefully unconstrained during inflation of the impermeable member410, such that the impermeable member410does fail at a prescribed condition. One embodiment of a flexible structural feature can include constrained membrane material740near a bond (e.g., a weld750) at lower pressures in order to maintain a primarily shear loading state in the bond, but then flexes at higher pressures to allow the membrane material740to hew towards perpendicular to the bond, leading to the critical peel loading state and subsequent failure as the bond peels apart. Such an embodiment can be desirable in some examples for safety to prevent the impermeable member410from reaching certain undesirable pressures or volumes by providing for failure of a bond to release fluid from the fluid cavity415of the impermeable member410.

Such a prescribed failure mode can have various other potential applications, including but not limited to allowing for near instantaneous collapse of the impermeable member410to allow any body supported by the impermeable member410to also collapse; to allow for a slow leak that allows for a slow collapse over time; for the expulsion of the internal fluid itself to cause a desired effect such as pushing an object away from the impermeable member410or to propel the impermeable member410in a direction, and the like.

In some embodiments, a fluid-impermeable member410, (e.g., a bladder defined at least in part by membrane material740), can be used to constrain a pressurized fluid whose function is to create an applied force or moment or to act as a volume or positioning element. Forces and moments may be transferred through one or more interface420, the fluid-impermeable member410, a supporting structural element, or some combination thereof. The fluid-impermeable member410may also comprise the fluidic actuator140simultaneously, such as in some cases when interfaces420and fluid-impermeable membrane materials740are integrated to form the fluid-impermeable member410, such that if by removing any, all, one or more than one interface420would result in the fluid-impermeable member410no longer being fluid-impermeable. In some embodiments, the fluid-impermeable member410, also called a bladder, can consist of or consist essentially of a fluid-impermeable membrane material740, such as a coated fabric, or the like.

The flexible fluid-impermeable member410(e.g., comprising membrane material740and/or a portion of one or more interfaces720that define a fluid-impermeable fluid cavity715) may take on any suitable geometry with varying lengths, shapes, sizes, orientations of shapes/volumes, combinations of shapes/volumes, segmentation, repetitions of volumes, amorphous geometries, etc. To create such a geometry, a fluid-impermeable membrane material740may be manipulated by a number of different methods, including but not limited to cutting with a blade and/or laser, stamping, folding, stitching, melting, burning, bonding, adhering, stapling, enveloping, tying, etc. Some embodiments of geometries, of which a fluid-impermeable member410(e.g., a bladder) may incorporate one or more combinations or repetitions of, in any orientations, include, but are not limited to, tubes, cylinders, pyramids, ovoids, toruses, toroids, cubes, spheres, bubbles, teardrops, frustums, cones, of various sizes, dimensions, volumes, lengths, variations, asymmetries, etc.

In one embodiment, generating the geometry of the fluid impermeable member410can comprise laser cutting a 2-D pattern onto a flat fluid-impermeable membrane material740, such as a coated fabric, and then using bonding techniques including but not limited to heat welding, sonic welding, RF welding, impulse welding, adhesives, and/or mechanical fasteners, which in some examples can be in conjunction with two hard plastic interfaces420to create a three-dimensional trapezoidal prismatic geometry. This can be achieved in some examples by bonding the fluid-impermeable membrane material740to generate a tube of and then bonding hard interfaces420shaped as trapezoids onto ends of the tube of fluid-impermeable membrane material740. In such an example, the fluid-impermeable membrane material740and interfaces420can form the fluid impermeable member410and the fluidic actuator140simultaneously with portions of the fluid-impermeable membrane material740and interfaces420defining a fluid cavity415of the fluid impermeable member410. For example,FIG. 11aillustrates an example embodiment of a fluid-impermeable membrane material740and a pair of interfaces420that can be coupled together to generate a fluidic actuator as shown inFIG. 11b. As discussed herein the fluid-impermeable membrane material740can be folded into a tube and welded together to generate a weld1100with the interfaces420coupled on opposing ends of the membrane material740to generate a fluid impermeable member410that defines a fluid cavity415. As discussed herein, the term tube or tube configuration should not be construed to be limiting on circular or rounded tubes and such terms should be construed to encompass elongated circumferences (e.g., of fluid-impermeable membrane material740), which may or may not have open ends. The length of such a tube or tube configuration can have a consistent cross-sectional shape and size or can be of varied shape and size. Additionally, in some embodiments, a tube or tube configuration can comprise convolutions or a smooth face.

In further examples,FIGS. 17aand 17billustrate top view of a fluidic actuator140having an interface420with membrane material740coupled about an edge of the interface420via a weld750.FIG. 17aillustrates a trapezoidal interface420andFIG. 17billustrates a rectangular interface420; however, various further embodiments can have interfaces420of any suitable shape and in some examples, the interfaces420can be different shapes or the same shape.

In some embodiments, a fluid impermeable member410can generated by coupling a plurality of stacked sheets of fluid-impermeable membrane material740. For example, as shown in the example ofFIGS. 12a, 12band 12c, a method of one embodiment can include generating (e.g., by laser cutting) multiple copies of a first shape1210with an opening1215in the middle of the first shape1210out of a flat fluid-impermeable membrane material740, such as a coated fabric. A second shape1230can be generated having the same size as the first shape1210, but with the opening1215being absent. An example of two of the first shape1210and two of the second shape1230are shown inFIG. 12a.

A fluid impermeable member410as shown in the example ofFIGS. 12band 12ccan be generated coupling by the four sheets ofFIG. 12atogether. For example, the two first shapes1210can be stacked on top of each other and bonded together along internal edge B1to generate a first coupling1250A between the first shapes1210. A second coupling1250B can be made by bonding one of the second shapes1230to one of the first shapes1210about edge A1and a third coupling1250C can be made by bonding the other one of the second shapes1230to the opposing one of the first shapes1210about edge A2.FIG. 12billustrates a side view andFIG. 12cillustrates a cross-sectional side view of the fluid impermeable member410that can be generated via such couplings andFIG. 12cillustrates that the generated fluid impermeable member410can define an enclosed fluid cavity415. The configuration ofFIGS. 12band 12b, or a portions thereof can be considered to be a “tube” or “tube configuration” as discussed herein. Accordingly, by a combination of bonding around outer edges A1, A2and the middle edges B1of the first shape1210, it is possible to create a multi-segmented fluid impermeable member410, similar to an accordion or bellows. In various embodiments, such a fluid impermeable member410can then be attached to two interfaces420to generate a fluidic actuator140.

The geometry and configuration of a fluidic actuator140, fluid impermeable member410, one or more interfaces420, membrane material740, and the like, can be designed to generate motion and/or force application in one, two, or more directions and/or apply a moment about any axis or combination of axes, including an instantaneous axis, series of instantaneous axes, and infinite axes. Given a pressurized fluid within the fluid cavity415, the fluid impermeable member410(e.g., a bladder) can be designed in some examples to apply a near-constant force application or varying forces dependent upon the inflation/expansion/contraction state of the fluid impermeable member410, the geometry and/or the construction of the interfaces420, and the like. Moments can be created by the actuator140in various ways including but not limited to methods which constrain the expansion/contraction of the fluid impermeable member410such that there is unequal extension/contraction of one face of the fluid impermeable member410relative to another face. This inequality can cause the fluid impermeable member410to rotate about an axis or set of axes (which may include an instantaneous or infinite axis—e.g. linear motion), with the resulting output forces at the ends of the fluid impermeable member410creating a moment about the aforementioned axes.

One embodiment of such a constraint can include the use of an elastic, semi-elastic, inextensible, or some combination thereof, strap or other length constraining element, such as a bungee, string, rope, or cable, to constrain the expansion of one side of the fluid impermeable member410relative to another during pressurization. One example embodiment of the use of a strap includes a strap that connects from one end of an interface420to another opposing interface420and lies across the body of the fluid impermeable member410. This strap can be shorter in length than the longest dimension of the fluid impermeable member in the direction of expansion during inflation. As the fluid impermeable member inflates, this strap can engage prior to maximum inflation, causing the side of the fluid impermeable member410nearest and underneath the strap to resist or stop expansion. Due to this constraint, one side of the fluid impermeable410member can expand more than the other, causing the fluid impermeable member410to expand in an arc. In other embodiments, a strap or combination of straps, can connect from one, two, or more of the interfaces420of the fluidic actuator to one, two, or more of any of the other interfaces420of the fluidic actuator to create such a constraint. In other embodiments, a strap or combination of straps could connect from one or more sub-chambers of the fluid impermeable member410to one or more other sub-chambers of the same fluid impermeable member410to create this constraint. In other embodiments, a strap or combination of straps could connect from one, two or more of the interfaces420of the fluidic actuator140to any other body, such as an exoskeleton structure, to create such a constraint. In other embodiments, a strap or combinations of straps can connect from any part of the fluidic actuator140, including the fluid impermeable member410, to any other part of the fluidic actuator140or other body, such as an exoskeleton structure or one, two or more other fluidic actuators140, to create such a constraint. In other embodiments, a strap or combination of straps connect to themselves while surrounding the fluid impermeable member410to create such a constraint.

For example,FIG. 21aillustrates a side cross-sectional view of an example embodiment of an actuator140comprising a fluid chamber415having a first and second sub-chamber415A,415B defined by first and second welds750A,750B that couple portions of membrane material740at external edges of the fluid impermeable member410. As shown in this example, one or more straps2110can be coupled to portions of membrane material740about the first and second welds750A,750B, which can constrain expansion of the fluid chamber415including the first and second sub-chambers415A,415B.

In another example,FIG. 21billustrates a side view of an example embodiment of an actuator140comprising straps2130coupled to and extending between a pair of opposing interfaces420, which can constrain expansion of a fluid impermeable member410between the interfaces420. Such straps2130can be coupled to various suitable portions of the interfaces420including external top faces, sidewalls, an underside, or the like. In some embodiments, such straps2130can be disposed circumferentially about the some or all of the perimeter of the actuator140.

Additionally, in various embodiments, such straps2110,2130can be different lengths, which may be desirable for constraining different portions of the actuator140. For example, straps of a first length on one side of the actuator140with straps2130of a second longer length on another side of the actuator140can allow differential expansion of the actuator140such that the interfaces420can be disposed at an angle to each other at various inflation states of the fluid impermeable member410. Such differential expansion via straps2130can be in addition to or in place of differential expansion based on different lengths of membrane material740on different portion of the actuator140(see e.g.,FIGS. 13a-c). As discussed herein, such differential expansion can cause the actuator140an arc configuration, curve configuration or the like, at various inflations states including at a maximum inflation state of the actuator140, and the like.

Also, while the example ofFIG. 21bshows vertical straps2130extending between the interfaces420, various embodiments can comprise one or more lateral straps that are looped or wrapped about the fluid impermeable member410as discussed herein. Additionally, various embodiments can comprise any suitable plurality of strapping configurations, so the examples herein showing a single strapping configuration such asFIGS. 21aand 21bshould not be construed as limiting.

One example embodiment of such a constraint can include the use of high-tension strings/cables tying together flaps along one side of a segmented fluid impermeable member410, such that during expansion, the tied side of the segmented fluid impermeable member410is constrained more than the opposing side of the fluid impermeable member410. As the fluid impermeable member410is pressurized, due to the constraint, one side of the fluid impermeable member410can expand more than the other, causing the fluid impermeable member410to expand in an arc.

For example, in some embodiments, a fluid chamber415of the fluid impermeable member410defines a plurality of sub-chambers, including a first and second sub-chamber. Inflation of the fluid chamber415applying a force to a first and second planar interface420can include maintaining the first sub-chamber at a static pressure and dynamically pressurizing the second sub-chamber.

In various embodiments, a multi-chamber fluid chamber415, a fluid chamber415having a plurality of sub-chambers or segments, or the like, can be used pressurized working fluid more efficiently over a dynamically changing large range of motion by keeping one chamber filled to a static pressure and another chamber dynamically pressurized. A fluidic actuator140can include a structure that allows for static or dynamic segmentation of the fluid impermeable member410, such that the fluid flow and pressure within each segment and/or between segments can be controlled, whether independently or dependently.

For example, dynamic segmentation can allows for one segment to be held at a quasi-static pressure and/or controlled dynamically and another or multiple other segments whose pressure can also be held at a quasi-static pressure and/or controlled dynamically, such that the interaction of these segments allows for efficient use of fluid, indicated by minimizing fluid flow into or out of any given segment, of pressurized fluid over a large dynamically changing range of motion of the fluid actuator140where the fluid actuator140may need to act over a small range of motion or a large range of motion, where a small range of motion is defined as less than half of the overall range of motion, and a large range of motion is defined as half or more of the overall range of motion, or any combination thereof. Overall ranges of motion for a fluid actuator140when related to moving two or more bodies relative to each other about an axis or set of axes can be described as varying between an angle of 0 degrees and 360 degrees or more about an axis or about each axis within a set of axes, where the angle is described as the angle formed between any pair of bodies whose motion is influenced by the actuator, where the measurement reference point of each body can be any fixed point relative to the body, such as a center of mass, corner, vertex, or even a point in 3D space fixed relative to each body, and an axis of rotation, and can be measured in either a clockwise or counterclockwise direction about an axis or each axis within the set of axes, and where angles greater than 360 degrees are associated to ranges of motion where a pair of bodies has made more than a single rotation about the axis, with some example overall ranges of motion being 720 degrees, 540 degrees, 360 degrees, 270 degrees, 180 degrees, 150 degrees, 120 degrees, 90 degrees, 60 degrees, 30 degrees, 10 degrees, and 0 degrees and the like. Overall ranges of motion for a fluid actuator140when related to moving two or more bodies relative to each other whose distances are measured from each other linearly, where those distance measurements can be measured from any fixed point relative to each body, such as a center of mass, corner, vertex, or even a point in 3D space fixed relative to each body, can vary from a length of 0 in to 6 ft or more, with some examples being 0.5 in, 1 in, 2 in, 3 in, 4 in, 5 in, 6 in, 6.5 in, 8 in, 10 in, 12 in, 14 in, 24 in and the like. The overall ranges of motion for a fluid actuator140can be described with linear measurements, rotational measurements, or any combination therein.

Other constraint methods can include, but are not limited to, the use of strapping of unequal lengths attached to different sides of a fluid impermeable member410, between different interfaces420, between interfaces and the fluid impermeable member410, between any part of the fluidic actuator140and itself, between parts of the fluidic actuator140and other bodies, and any combination thereof, the geometry of the fluid-impermeable member410itself where one or more sides of the fluid impermeable member410are unequal in dimension, and the like.

One example embodiment where the geometry creates such a constraint can be a fluid impermeable member410that inflates into the shape of a trapezoidal prism. As this fluid impermeable member410inflates, once the short side of the trapezoidal prism is at its max length, it can no longer expand on that side. The opposing longer side of the fluid impermeable member410can continue to expand, causing the ends of the fluid impermeable member410to no longer be parallel and can instead be at an angle with each other. In rotating from parallel to at an angle with each other, the ends of the fluid impermeable member410can create a moment about an axis.

For example,FIGS. 13a, 13band 13cillustrate an example embodiment of a fluidic actuator140having a first and second opposing interface420with a membrane material740coupled thereto, which defines a fluid impermissible member410and a fluid chamber415. The example actuator is shown having first and second sides S1, S2with the first side S1being shorter than the second side S2. As shown inFIG. 13a, the interfaces can be in a parallel configuration where both sides S1, S2are in a collapsed configuration (e.g., due to pressure of fluid within the fluid chamber415, force applied to the interfaces420, or the like), which can cause membrane material740on the sides S1, S2to bulge outward.FIG. 13billustrates a configuration of the actuator140where the interfaces420are in a parallel configuration where the first side S1has reached a maximum length, whereas the second side S2has not reached a maximum length.FIG. 13cillustrates a configuration of the actuator140where both the first and second sides S1, S2have reached a maximum length such that the interfaces420are disposed at an angle A.

In some embodiments the membrane material740can comprise an inextensible yet flexible material (see e.g.,FIG. 5), which allows the membrane material740to be flexible (e.g., S1and S2inFIGS. 13aand S2inFIG. 13b) and become inextensible or substantially inextensible at a maximum length (e.g., S1and S2inFIGS. 13cand S1inFIG. 13b).FIGS. 4aand 4billustrate another example of a fluidic actuator140that can expand differentially based on different lengths or geometries of a membrane material740or fluid impermissible member410.

In various examples, such moment generation by a fluidic actuator140can be useful in applications for body worn devices such as orthotics or exoskeletons100, where assistive torque application about various joints such as the ankle, knee, hip, and elbows can provide useful assistance to the user. Different combinations of length, angle, and size can allow for fine-tuning adjustments and customizations of the desired actuator torque and force direction and magnitude over inflation time.

In some embodiments, force output can be a function of, but not limited to, the contact surface area of the fluid impermissible member410(e.g., a bladder) against a body (upon which the force is being applied such as one or more portion of an exoskeleton or directly to one or more portion of a body of a user); the contact area of the fluid impermissible member410against one or more interface420; the contact area of the fluid impermissible member410against itself, as well as the fluidic pressure at those contact areas. If that contact area can be made to grow or diminish as the actuator140inflates and/or deflates, it can be possible in some examples to alter the force output of the actuator140through in such a way rather than through changing the fluidic pressure in a fluid chamber415alone. Some embodiments can include an interface420with a geometry and construction that can allow for variation in the contact area, which can be accomplished in various suitable ways, including but not limited to one or more interface420flexing as the fluid pressure/volume within the fluid chamber415of the fluid impermissible member410changes, and where such flexing causes a contact area of the interface420with another body to change. Further embodiments can include one or more interface420with sliding elements that can allow the interface420to change contact area by the one or more interface420itself growing or shrinking in surface area, or simply by changing the orientation of the interface420against another body which may allow for a change in the contact surface area.

Some embodiments can include a fluid-impermeable member410with variable cross-sectional area and/or asymmetric shape as well as multiple fluid-impermeable members410with these characteristics that work in series, parallel or any combination thereof. One embodiment can include a contact area with another body that is greater when the fluid-impermeable member410is compressed and reduces as the fluid-impermeable member410expands. The converse can also be present in some embodiments. Such an embodiment in some examples may provide more force during the beginning of inflation rather than the end at a given fluidic pressure which in some examples can be useful in applications where the timing of that force application is useful, such as in a wearable exoskeleton that assists with walking and running gaits. One example embodiment can include fluid-impermeable member410(e.g., a bladder) whose geometry is a cone. When collapsed, such a fluid-impermeable member410can have a contact area with another body equal to or greater than the base of the cone. As the cone expands, if the body is in contact with the pointed end of the cone, the cross-sectional area of the cone in contact with the body can shrinks. Another example embodiment can include a fluidic actuator140comprising of two opposing interfaces420on either end of a fluid-impermeable member410having a geometry of diminishing cross section, such as a conical or pyramidal frustum. A conical or pyramidal frustum can, in general, have one side that is larger in surface area than the opposing side, referred henceforth in this example as base and top, respectively. While the interfaces420can be of the same geometry and dimension, the fluid-impermeable member410can have a larger cross-sectional area at a connection to an interface420at the base of the frustum and a smaller cross sectional area at a top interface420. Regardless of geometry, in some embodiments it is possible in the collapsed state for the cross sectional contact area of the fluid-impermeable member410with the two interfaces420to actually be greater than the maximum created at full inflation of the fluid-impermeable member410, as the fluid-impermeable member410can balloon circumferentially during inflation when the two interfaces420can be close in proximity in the collapsed state due to the flexibility of a fluid-impermeable membrane material740that is part of the fluid-impermeable member410. Expanding in this circumferential direction can lead to increased contact area with the two interfaces420. As the fluid chamber415of the fluid-impermeable member410inflates from a pressurized fluid, the interfaces420can move away from each other and the contact area of the fluid-impermeable member410with the interfaces can reduce. This can create the effect of a variable force output of the fluid-impermeable member410without the need to manipulate the pressure of the working fluid. In the case of the frustum, this variable force output can be a reduction as the fluid-impermeable member410expands, whose reduction can in some examples be controlled by controlling the geometry of the frustum.

Another similar example embodiment can comprise a bladder geometry that resembles two frustums connected at their tops, resulting in an inflated fluid-impermeable member410with a minimum cross sectional area at a mid-plane of the fluid-impermeable member410. In this way, a similar effect can achieved in some examples with a reduction in cross-sectional area during inflation/expansion of the fluidic actuator140, which can results in a reduction of output force at a given pressure in some embodiments.

Such examples can be extrapolated to further embodiments having any suitable segmented fluid-impermeable member410geometry, whether the segments of the fluid-impermeable member410are created by one or more interface420, supporting structural elements, with a fluid-impermeable membrane material740itself, or any combination thereof. In some examples, segmentation of the fluid-impermeable member410can include a variable cross-section within the fluid-impermeable member410(e.g., within a bladder), including a slight or insubstantial change in cross-section, and similar variable force outputs may be achieved in some examples without necessitating the need for manipulating the pressurization of the working fluid.

In various embodiments, a fluid-impermeable member410can comprise membrane materials740such as coated synthetic fabrics, elastomers, urethanes, silicones, rubbers, natural textiles, and the like. Such membrane materials740can be compliant, semi-compliant, or non-compliant engineering materials that have fluid-impermeable or near fluid-impermeable properties. In various embodiments, a fluid-impermeable member410and/or membrane materials740can experience low strain once inflated to full volume and especially at high pressure, meaning that in some examples, the fluid-impermeable member410and/or membrane material740does not stretch significantly at high pressures, giving similar actuator volumes over a range of pressures. This can be in contrast to the example of a rubber party balloon, whose volume can be highly dependent on a fluid volume and pressure and can fail at high pressures due to excessive strain in the material. Accordingly, in some embodiments it can be desirable for a fluid-impermeable member410and/or membrane material740to comprise an inextensible yet flexible material as discussed herein.

In some embodiments, fluid-impermeable member410can be defined at least in part by a membrane material740having a plurality of layers. For example, a membrane material740can comprise an internal first layer that defines a fluid cavity415and can comprise an outer second layer with a third layer disposed between the first and second layers. Throughout this example, the use of the term ‘layer’ to describe the construction of the membrane material740should not be viewed as limiting to the design. The use of ‘layer’ can refer to a variety of designs including but not limited to: a planar material sheet, a wet film, a dry film, a rubberized coating, a co-molded structure, and the like.

In some examples, the internal first layer can comprise a material that is impermeable or semi-permeable to the actuator fluid (e.g., air) and the external second layer can comprise an inextensible yet flexible material as discussed herein. For example, as discussed herein, an impermeable layer can refer to an impermeable or semi-permeable layer and an inextensible layer can refer to an inextensible or a practically inextensible layer.

In some embodiments comprising two or more layers, the internal layer can be slightly oversized compared to an inextensible outer second layer such that the internal forces can be transferred to a high-strength inextensible outer second layer. One embodiment comprises an impermeable member410made with a membrane material740having an impermeable polyurethane polymer film inner first layer and a woven nylon braid as the outer second layer.

An impermeable member410and/or a membrane material740can be constructed in various suitable ways in further embodiments, which can include a single layer design that is constructed of a material that provides both fluid impermeability and that is sufficiently inextensible. Other examples can include a complex bladder assembly that comprises multiple laminated layers that are fixed together into a single structure. In some examples, it can be desirable to limit the deflated stack height of the bladder to maximize the range of motion of the fluidic actuator140. In such an example, it can be desirable to select a low-thickness fabric that meets the other performance needs of the fluidic actuator140.

In yet another embodiment, it can be desirable to reduce friction between the various layers of a membrane material740. In one embodiment, this can include the integration of a third layer that acts as an anti-abrasive and/or low friction intermediate layer between the first and second layers. Other embodiments can reduce the friction between the first and second layers in alternative or additional ways, including but not limited to the use of a wet lubricant, a dry lubricant, or multiple layers of low friction material. Accordingly, while the above example illustrates an embodiment comprising three layers, further embodiments can include any suitable number of layers, including one, two, three, four, five, ten, fifteen, twenty five, and the like.

Such one or more layers can be coupled together along adjoining faces in part or in whole, with some examples defining one or more cavity between layers. In such examples, material such as lubricants or other suitable fluids can be disposed in such cavities or such cavities can be effectively empty. Additionally, as described herein, one or more layers (e.g., the third layer) need not be a sheet or planar material layer as discussed in some examples and can instead comprise a layer defined by a fluid. For example, in some embodiments, the third layer can be defined by a wet lubricant, a dry lubricant, or the like.

The inflated shape of the fluid impermeable member410can be important to the operation of the fluidic actuator140and/or exoskeleton100in some embodiments. For example, the inflated shape of the fluid impermeable member410can be affected through the design of both an impermeable and inextensible portion of the fluid impermeable member410(e.g., the first and second layer). In various embodiments, it can be desirable to construct one or more of the layers of the fluid impermeable member410out of various two-dimensional panels that may not be intuitive in a deflated configuration.

In some embodiments, one or more fluid-impermeable layers can be disposed within the fluid cavity415and/or the fluid impermeable member410can comprise a material that is capable of holding a desired fluid (e.g., a fluid-impermeable first internal layer as discussed herein). The fluid impermeable member410can comprise a flexible, elastic, or deformable material that is operable to expand and contract when the fluid impermeable member410is inflated or deflated as described herein. In some embodiments, the fluid impermeable member410can be biased toward a deflated configuration such that the fluid impermeable member410is elastic and tends to return to the deflated configuration when not inflated.

Additionally, although some embodiments of a fluid impermeable member410shown herein are configured to expand and/or extend when inflated with fluid, in some embodiments, fluid impermeable member410can be configured to shorten and/or retract when inflated with fluid in some examples.

In various embodiments, a fluid-impermeable member410can be constructed of one or more fluid-impermeable membrane materials740and/or one or more fluid-impermeable interfaces420. Such components can be bonded together to define one or more fluid chamber415comprising one or more closed volumes capable of being pressurized with fluid as discussed herein. Any suitable bonding method can be used including but not limited to heat welding, radio-frequency welding, adhesives, epoxies, mechanical bonds, and other joining methods and any combination thereof, including permanent or semi-permanent bonds. Such bonding methods may be assisted with the use of supporting components which can include but are not limited to fixturing jigs, dies, clamps, tapes, adhesives, mechanical fasteners, and the like, which can serve the purpose of: focusing the application of the bonding method; locating materials relative to each other to provide more accurate bonding; acting as a heat sink to cool those bonds that require heating to prevent materials from shifting relative to each other during cooling; applying pressure to bonds during cooling of the bond to create stronger bonds, and the like. Such a bonding process can comprise use of locating features in the components such as the fluid-impermeable member410and/or interface(s)420, including pins, holes, screws, bosses, debosses, slides, tracks, hooks, clips, and other features that can have a male/female relationship that can aid with locating two components relative to each other.

In some embodiments, the fluid-impermeable member410comprises, consists essentially of or consists of two opposing rigid plate interfaces420bonded to a tube of a fluid-impermeable membrane740. In one example embodiment, such bonding can be done partially or entirely with lap joints, which can be configured to maintain loading at the joints primarily in shear rather than peel during pressurization. In another example embodiment, such bonds can include lap and/or peel welds. For example,FIG. 14aillustrates an example of a peel weld750between a first and second element1410,1420andFIG. 14billustrates a lap weld between a first and second element1410,1420. In various embodiments, the first and/or second element can include a membrane material740, interface420, or the like.

In some examples where peel welds are used, such welds can be supported during inflation, especially at high pressure, with support structures as discussed herein, as well as by other suitable structures or methods of preventing the material adjacent to the peel welds from reaching a critical peel angle. This can be accomplished in some examples by controlling the inflation of a fluid impermeable member410in such a way as to hold membrane material740adjacent to a bond close together during inflation fluid impermeable member410, such that tension within the membrane material740can hew closer to parallel with the bond and not reach a critical peel state. For example,FIG. 15illustrates an embodiment of a fluid impermeable member410comprising a first and second portion of membrane material740coupled together via welds750to define a fluid chamber415. By constraining the inflation of the fluid impermeable member410to a maximum width W1, can minimize the normal component of a tension force relative to the welds750, which can minimizes peeling of the peel welds750.

Limiting the inflation volume, bulging, ballooning or lateral expansion of a fluid impermeable member410(e.g., a bladder) can be done with various suitable constraints. Some example embodiments can include the use of straps, ropes, strings, cables or the like, to constrain the geometric expansion of a fluid impermeable member410to create such a constraint. Such straps, ropes, strings, cables, or the like can be wrapped around a fluid impermeable member410creating this constraint. For example, a strap can be helically wrapped around a fluid impermeable member410along a length of a fluid impermeable member410or one or more loops of strapping can be disposed around a length of the a fluid impermeable member410. In further examples, such constraints can be internal to the fluid impermeable member410, such as within a fluid chamber415, and can be attached between two or more faces of the fluid impermeable member410to constrain the faces from moving away from each other during pressurization.

Such constraints can also be used to constrain the fluid chambers415of a multi chambered bladder from expanding too much by restricting the expansion of the entire fluid impermeable member410or between fluid chambers415of the fluid impermeable member410. For example,FIGS. 16aand 16billustrate a fluid impermeable member410defined by portions of a membrane material740coupled together at a plurality of welds750to define a fluid chamber415having a first and second fluid chamber portion415A,415B. In some embodiments, such an impermeable member410having a plurality of fluid chambers415or fluid chamber portions can be constrained via external constraints and/or internal constraints that extend within one or more fluid chambers or portions, or between a plurality of fluid chambers or portions.

Constraints (e.g., external strapping) to limit the volumetric expansion of the fluid chamber415can be configured such that any peel welds (see e.g.,FIGS. 14a,15,16aand16b) never reach their failure state in peel. For example, in some embodiments, constraints can be configured such that the sections membrane material740on opposing sides of a peel weld are prevented from extending away from the weld no more than 45 degrees from each other at maximum inflation of the fluid chamber415, which can be desirable to prevent failure of the peel welds. In further embodiments, constraints can be configured such that the section of membrane material740on opposing sides of a peel weld are prevented from extending away from the weld no more than 40, 35, 30, 25, 20, 15, 10 or 5 degrees from each other at maximum inflation of the fluid chamber415. Such a maximum allowed angle can depend on the bond/weld strength, the strength of a coating bond with a fabric, the like. As discussed herein, such constraint can be desirable for single chamber or multi-chamber fluid chambers415(see, e.g.,FIGS. 15, 16aand16b).

In some embodiments, one or more piece of fluid-impermeable membrane material740may be used to reinforce bonds by overlapping bond sites, (e.g., creating a lap joint where one did not exist before or reinforcing a joint that was already there). Such overlapping membrane material740may also be used to smooth transitions in the fluid-impermeable member410that may be due to the creation of bonds or any other existing geometries or features of the fluid-impermeable member410. In some examples, overlapping membrane material740may also serve to strengthen and/or stiffen sections of a fluid-impermeable member410by adding thickness or through the use of different membrane materials740with different strength and stiffness properties. In some examples, an overlapping membrane material740may assist with avoiding failure of the fluid-impermeable member410at high pressures, protect the fluid-impermeable member410from puncture, increase the life of the fluid-impermeable member410due to pressurization cycling, and the like.

A fluidic actuator140in some examples can comprise components such as one or more fluid-impermeable members410(e.g., defined at least in part by a membrane material740), one or more interfaces420, structural components and the like. Such components can be joined together utilizing various suitable methods including but not limited to one or more of heat welding, radio-frequency welding, adhesives, epoxies, mechanical bonds, mechanical fasteners, sewing, magnets, electromagnets, staples, and other joining methods such as clamping and any combination thereof.

Some embodiments can include strengthening or reinforcing a weld or bond (e.g., between portions of a fluid impermeable membrane material740or between an interface420and a fluid impermeable membrane material740) by sewing stiches along the weld/bond (e.g., on the weld/bond, parallel to the weld/bond, or the like) and then reinforcing the stitches with more membrane material740, adhesive or the like. Such a reinforcement in some examples can be desirable for re-establishing fluid impermeability due to the puncturing of the membrane material740that may have occurred during sewing.

One embodiment of a fluidic actuator140can include rigid interfaces420integrated with an airtight bladder (e.g., a bladder comprising a membrane material740) such that the bladder would not be airtight without the rigid interfaces420. In other words, some embodiments of a fluidic actuator140can comprise an impermeable member410and a fluid cavity415defined by a first and second interface420and a membrane material740. Such an integration, in some examples, can be created such that all or nearly all bonding between the bladder and interfaces420and within the bladder itself are composed of shear welds, where upon inflation of the impermeable member410(e.g., an integrated bladder/interface system), materials at any bond experiences predominantly shear forces. One way to accomplish such shear-bonding in some examples is through the use of lap joints at some or all bonds between surfaces. This can make some embodiments of a fluidic actuator140optimal for reaching and operating at pressures relative to the surrounding atmosphere (referred to as gage pressure) greater than or equal to 5 psi, 10 psi, 20 psi, 30 psi, 50 psi, 75 psi, 100 psi, 150 psi, 200 psi, and the like over a number of cycles of inflation and deflation numbering greater than or equal to 10 cycles, 20 cycles, 30 cycles, 50 cycles, 75 cycles, 100 cycles, 1000 cycles, 5000 cycles, 10,000 cycles, 100,000 cycles, 1 million cycles and the like.

One embodiment of such a shear weld construction can include a fluid cavity created by a section of fluid impermeable membrane material740wrapped into a tube and welded to itself in a lap/shear weld, with a first and second interface420inserted into each end of the tube such that the fluid impermeable membrane material740overhangs the interfaces420on each end. This overhanging fluid impermeable material740can then be welded to the external faces of each interface420and/or to itself where folding of the fluid impermeable material740may be required, which can create the fluid impermeable member410and fluidic actuator140simultaneously. In one example embodiment, when the weld is made between the membrane material740and the edge or near the edge of the external face of the interface420, such a weld can experience predominantly shear forces during inflation of the fluidic actuator140.

For example,FIG. 20illustrates an example embodiment of a fluidic actuator140comprising a first and second interface420, where a membrane material740extends between the interfaces420and is coupled to an external face of the interfaces420via a bond or weld750. In the example ofFIG. 20, the membrane material is coupled to an external face of a lip724that defines an interface cavity726; however, it should be clear that such a coupling is applicable to interfaces420of various suitable embodiments, including interfaces420having a flat external face, rounded external face, without an interface cavity726, or the like.

Additionally, such a coupling on the external face of one or more interface420can contiguous (e.g., a contiguous circumferential weld750about the perimeter of the interface420proximate to an edge), or can comprise a plurality of separate couplings, which may or may not generate a fluid impermissible coupling. For example, such a coupling can comprise a plurality of spot welds, tacking of the membrane material740to the interface420, or the like. Additionally, while examples such asFIGS. 20 and 7, 8, 13a-cand18illustrate bonds, couplings or welds750on either of the sidewalls or external face of the interfaces420, it should be clear that various embodiments can comprise bonds, couplings or welds750on both of the sidewalls or external face of the interfaces420, with one or both of such bonds, couplings or welds750defining a fluid impermissible coupling.

When one or more fluidic actuator140is used to actuate a body-worn exoskeleton100or exoskeleton system200(see e.g.,FIGS. 1, 2 and 3), one embodiment of a fluidic actuator140comprises interfaces140that are integrated into the exoskeleton system200, such that a fluid-impermeable membrane740can be connected to the interfaces420to form the fluidic actuator140and fluid-impermeable member410simultaneously. Another embodiment comprises interfaces420and fluid-impermeable membrane material740forming a fluidic actuator140which is then connected to the exoskeleton100or exoskeleton system200.

In some embodiments, example designs, geometries, construction methods, and embodiments described herein allow for robust small fluidic actuators140capable of reaching and operating at pressures relative to the surrounding atmosphere (referred to as gage pressure) greater than or equal to 5 psi, 10 psi, 20 psi, 30 psi, 50 psi, 75 psi, 100 psi, 150 psi, 200 psi, and the like, without the fluidic actuator failing140(e.g., to failure of welds, a membrane material740, or the like). Current industry methods are incapable of producing small high-pressure fluidic actuators, as may know actuators rely on peel welds throughout their construction which can be prone to failure at high pressures. The high power-to-weight ratio inherent in a small fluidic actuator140of various embodiments that is capable of reaching high-pressures, especially when the working fluid is a gas, can be advantageous in many powered applications, (e.g., body-worn exoskeletons100or exoskeleton systems), where in some examples it can be desirable to minimize distal mass.

The described embodiments are susceptible to various modifications and alternative forms, and specific examples thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the described embodiments are not to be limited to the particular forms or methods disclosed, but to the contrary, the present disclosure is to cover all modifications, equivalents, and alternatives. Additionally, elements of a given embodiment should not be construed to be applicable to only that example embodiment and therefore elements of one example embodiment can be applicable to other embodiments. Additionally, elements that are specifically shown in example embodiments should be construed to cover embodiments that comprise, consist essentially of, or consist of such elements, or such elements can be explicitly absent from further embodiments. Accordingly, the recitation of an element being present in one example should be construed to support some embodiments where such an element is explicitly absent.