Patent Description:
Soft robotic actuators have recently been employed in contexts in which traditional hard actuators may be inappropriate or may suffer from deficiencies. For example, in food handling, it may be advantageous to use soft robotic actuators because of their improved ability to conform to the article being grasped, thus preventing the food from becoming marred or bruised. For similar reasons, soft actuators may be used in medical settings.

Whether a hard robotic actuator or a soft robotic actuator is employed, the handling of certain biological or chemical materials may pose unique problems. Hard and soft robotic systems may include numerous crevices, surface roughness, indentations, fasteners, and other areas where the biological or chemical materials may accumulate and breed bacteria or spread potentially poisonous matter to other products. Traditionally, it may be difficult to remove accumulated biological or chemical materials, thus creating a contamination hazard.

<CIT> relates to an object gripping device for gripping an object with a soft touch like a human hand when gripping an object in a hand part of an industrial robot or other interacting mechanical part.

<CIT> relates to a finger for a robot hand comprising a tubular body of a flexible material which can be bent by internal pressure.

The invention provides a soft actuator as set out in the accompanying claims. The present application addresses improvements in robotic systems to reduce biological or chemical harborage points on the systems. Exemplary embodiments relate to improvements in robotic actuators, grippers, hubs for connecting the actuators or grippers to a robotic arm, entire robotic systems, and other components. According to exemplary embodiments, fasteners and mounting points may be moved to internal locations on actuators and hubs, so as to present a smooth, flat surface without corners, crevices, or other points for biological or chemical materials to accumulate. Attachment points may be configured to use twist-interlock systems having rounded interlocking pieces that are easier to clean than sharp corners. Distances between adjacent components (e.g., accordion extensions on actuators) may be increased, and curves added or increased in size, to reduce harborage points. Similarly, specially-configured coverings may be employed to present a flat surface on which biological or chemical materials will exhibit reduced accumulation or which may be readily cleaned; in some embodiments, the coverings may be disposable.

Moreover, some embodiments provide actuators having improved designs for handling food, biological materials such as tissue, and other delicate or easily bruised or deformed materials.

Although exemplary embodiments are described in connection with soft robotic actuators, similar techniques may be employed with more traditional hard robotic systems.

Exemplary embodiments relate to robotic systems that are designed or configured to reduce biological or chemical harborage points on the systems. For example, in exemplary embodiments, robotic actuators, hubs, or entire robotic systems may be configured to allow crevices along joints or near fasteners to be reduced or eliminated, hard corners to be replaced with rounded edges, certain components or harborage points to be eliminated, shapes to be reconfigured to be smoother or flat, and/or or surfaces to be reconfigurable for simpler cleaning. Improved actuator designs for handling certain types of biological or chemical materials are also disclosed.

Exemplary embodiments may be advantageously employed in conjunction with soft robotic actuators. Soft robotic actuators are relatively non-rigid actuators that may be actuated by, for example, by filling the actuator with a fluid such as air or water. The soft actuator may be configured so that, by varying the pressure of the fluid in the actuator, the shape of the actuator changes. Accordingly, the actuator can be made to, for instance, wrap around an object. Because the soft actuator is relatively non-rigid, the actuator may better conform to the surface of the grasped object, allowing the actuator to gain a better hold on the object or more gently hold fragile objects.

A brief overview of soft robotic actuators and grippers will first be provided, followed by a detailed description of various aspects of exemplary embodiments. Unless otherwise noted, it is contemplated that each of the described embodiments may be used in any combination with each other.

Conventional robotic grippers or actuators may be expensive and incapable of operating in certain environments where the uncertainty and variety in the weight, size and shape of the object being handled has prevented automated solutions from working in the past. The present application describes applications of novel soft robotic actuators that are adaptive, inexpensive, lightweight, customizable, and simple to use.

Soft robotic actuators may be formed of elastomeric materials, such as rubber, or thin walls of plastic arranged in an accordion structure that is configured to unfold, stretch, twist and/or bend under pressure, or other suitable relatively soft materials. They may be created, for example, by molding one or more pieces of the elastomeric material into a desired shape. Soft robotic actuators may include a hollow interior that can be filled with a fluid, such as air, water, or saline to pressurize, inflate, and/or actuate the actuator. Upon actuation, the shape or profile of the actuator changes. In the case of an accordion-style actuator (described in more detail below), actuation may cause the actuator to curve or straighten into a predetermined target shape. One or more intermediate target shapes between a fully unactuated shape and a fully actuated shape may be achieved by partially inflating the actuator. Alternatively or in addition, the actuator may be actuated using a vacuum to remove inflation fluid from the actuator and thereby change the degree to which the actuator bends, twists, and/or extends.

Actuation may also allow the actuator to exert a force on an object, such as an object being grasped or pushed. However, unlike traditional hard robotic actuators, soft actuators maintain adaptive properties when actuated such that the soft actuator can partially or fully conform to the shape of the object being grasped. They can also deflect upon collision with an object, which may be particularly relevant when picking an object off of a pile or out of a bin, since the actuator is likely to collide with neighboring objects in the pile that are not the grasp target, or the sides of the bin. Furthermore, the amount of force applied can be spread out over a larger surface area in a controlled manner because the material can easily deform. In this way, soft robotic actuators can grip objects without damaging them.

Moreover, soft robotic actuators allow for types of motions or combinations of motions (including bending, twisting, extending, and contracting) that can be difficult to achieve with traditional hard robotic actuators.

<FIG> depict exemplary soft robotic actuators. More specifically, <FIG> depicts a side view of a portion of a soft robotic actuator. <FIG> depicts the portion from <FIG> from the top. <FIG> depicts a side view of a portion of the soft robotic actuator including a pump that may be manipulated by a user. <FIG> depicts an alternative embodiment for the portion depicted in <FIG>.

An actuator may be a soft robotic actuator <NUM>, as depicted in <FIG>, which is inflatable with an inflation fluid such as air, water, or saline. The inflation fluid may be provided via an inflation device <NUM> through a fluidic connection <NUM>.

The actuator <NUM> may be in an uninflated state in which a limited amount of inflation fluid is present in the actuator <NUM> at substantially the same pressure as the ambient environment. The actuator <NUM> may also be in a fully inflated state in which a predetermined amount of inflation fluid is present in the actuator <NUM> (the predetermined amount corresponding to a predetermined maximum force to be applied by the actuator <NUM> or a predetermined maximum pressure applied by the inflation fluid on the actuator <NUM>). The actuator <NUM> may also be in a full vacuum state, in which all fluid is removed from the actuator <NUM>, or a partial vacuum state, in which some fluid is present in the actuator <NUM> but at a pressure that is less than the ambient pressure. Furthermore, the actuator <NUM> may be in a partially inflated state in which the actuator <NUM> contains less than the predetermined amount of inflation fluid that is present in the fully inflated state, but more than no (or very limited) inflation fluid.

In the inflated state, the actuator <NUM> may exhibit a tendency to curve around a central axis as shown in <FIG>. For ease of discussion, several directions are defined herein. An axial direction passes through the central axis around which the actuator <NUM> curves, as shown in <FIG>. A radial direction extends in a direction perpendicular to the axial direction, in the direction of the radius of the partial circle formed by the inflated actuator <NUM>. A circumferential direction extends along a circumference of the inflated actuator <NUM>.

In the inflated state, the actuator <NUM> may exert a force in the radial direction along the inner circumferential edge of the actuator <NUM>. For example, the inner side of the distal tip of the actuator <NUM> exerts a force inward, toward the central axis, which may be leveraged to allow the actuator <NUM> to grasp an object (potentially in conjunction with one or more additional actuators <NUM>). The soft robotic actuator <NUM> may remain relatively conformal when inflated, due to the materials used and the general construction of the actuator <NUM>.

The actuator <NUM> may be made of one or more elastomeric materials that allow for a relatively soft or conformal construction. Depending on the application, the elastomeric materials may be selected from a group of food-safe, biocompatible, or medically safe, FDA-approved materials. The elastomeric materials may also be a fluoropolymer elastomer for chemical resistance. The actuator <NUM> may be manufactured in a Good Manufacturing Process ("GMP")-capable facility.

The actuator <NUM> may include a base <NUM> that is substantially flat (although various amendments or appendages may be added to the base <NUM> in order to improve the actuator's gripping and/or bending capabilities). The base <NUM> may form a gripping surface that grasps a target object.

The actuator <NUM> may include one or more accordion extensions <NUM>. The accordion extensions <NUM> allow the actuator <NUM> to bend or flex when inflated, and help to define the shape of the actuator <NUM> when in an inflated state. The accordion extensions <NUM> include a series of ridges <NUM> and troughs <NUM>. The size of the accordion extensions <NUM> and the placement of the ridges <NUM> and troughs <NUM> can be varied to obtain different shapes or extension profiles.

Although the exemplary actuator of <FIG> is depicted in a "C" or oval shape when deployed, one of ordinary skill in the art will recognize that the present invention is not so limited. By changing the shape of the body of the actuator <NUM>, or the size, position, or configuration of the accordion extensions <NUM>, different sizes, shapes, and configurations may be achieved. Moreover, varying the amount of inflation fluid provided to the actuator <NUM> allows the actuator <NUM> to take on one or more intermediate sizes or shapes between the uninflated state and the inflated state. Thus, an individual actuator <NUM> can be scalable in size and shape by varying inflation amount, and an actuator can be further scalable in size and shape by replacing one actuator <NUM> with another actuator <NUM> having a different size, shape, or configuration.

The actuator <NUM> extends from a proximal end <NUM> to a distal end <NUM>. The proximal end <NUM> connects to an interface <NUM>. The interface <NUM> allows the actuator <NUM> to be releasably coupled to other parts of a robotic system. The interface <NUM> may be made of a medically safe material, such as polyethylene, polypropylene, polycarbonate, polyetheretherketone, acrylonitrile-butadiene-styrene ("ABS"), or acetal homopolymer. The interface <NUM> may be releasably coupled to one or both of the actuator <NUM> and the flexible tubing <NUM>. The interface <NUM> may have a port for connecting to the actuator <NUM>. Different interfaces <NUM> may have different sizes, numbers, or configurations of actuator ports, in order to accommodate larger or smaller actuators, different numbers of actuators, or actuators in different configurations.

The actuator <NUM> may be inflated with an inflation fluid supplied from an inflation device <NUM> through a fluidic connection such as flexible tubing <NUM>. The interface <NUM> may include or may be attached to a valve <NUM> for allowing fluid to enter the actuator <NUM> but preventing the fluid from exiting the actuator (unless the valve is opened). The flexible tubing <NUM> may also or alternatively attach to an inflator valve <NUM> at the inflation device <NUM> for regulating the supply of inflation fluid at the location of the inflation device <NUM>.

The flexible tubing <NUM> may also include an actuator connection interface <NUM> for releasably connecting to the interface <NUM> at one end and the inflation device <NUM> at the other end. By separating the two parts of the actuator connection interface <NUM>, different inflation devices <NUM> may be connected to different interfaces <NUM> and/or actuators <NUM>.

The inflation fluid may be, for example, air or saline. In the case of air, the inflation device <NUM> may include a hand-operated bulb or bellows for supplying ambient air. In the case of saline, the inflation device <NUM> may include a syringe or other appropriate fluid delivery system. Alternatively or in addition, the inflation device <NUM> may include a compressor or pump for supplying the inflation fluid.

The inflation device <NUM> may include a fluid supply <NUM> for supplying an inflation fluid. For example, the fluid supply <NUM> may be a reservoir for storing compressed air, liquefied or compressed carbon dioxide, liquefied or compressed nitrogen or saline, or may be a vent for supplying ambient air to the flexible tubing <NUM>.

The inflation device <NUM> further includes a fluid delivery device <NUM>, such as a pump or compressor, for supplying inflation fluid from the fluid supply <NUM> to the actuator <NUM> through the flexible tubing <NUM>. The fluid delivery device <NUM> may be capable of supplying fluid to the actuator <NUM> or withdrawing the fluid from the actuator <NUM>. The fluid delivery device <NUM> may be powered by electricity. To supply the electricity, the inflation device <NUM> may include a power supply <NUM>, such as a battery or an interface to an electrical outlet.

The power supply <NUM> may also supply power to a control device <NUM>. The control device <NUM> may allow a user to control the inflation or deflation of the actuator, e.g. through one or more actuation buttons <NUM> (or alternative devices, such as a switch). The control device <NUM> may include a controller <NUM> for sending a control signal to the fluid delivery device <NUM> to cause the fluid delivery device <NUM> to supply inflation fluid to, or withdraw inflation fluid from, the actuator <NUM>.

As used herein, an actuator typically refers to a single component resembling the actuator <NUM>. When multiple actuators are employed together to form a gripping system that grips a target, such a system is generally referred to as a gripper (although some grippers may consist of a single actuator that grips a target in isolation).

Actuators or grippers may be mounted to a robotic arm (for example) either directly or through a separate interface such as a hub. Problematically, the connection between various components may include crevices or corners that accumulate materials and may be difficult to clean.

It is noted that actuators, grippers, and robotic systems may be cleaned in-place or out-of-place. In-place cleaning generally refers to cleaning some or all of a robotic system while the various parts of the system are still connected, without disassembly. For example, in-place cleaning may involve scrubbing an actuator and gripper assembly while the assembly remains mounted to a robotic arm. Out-of-place cleaning generally involves disassembling the assembly to clean the parts individually and/or access internal areas of the parts. Exemplary embodiments provide hubs and mounting locations having fewer or smaller harborage points (thus collecting less bacterial, biological, or chemical material). Moreover, exemplary embodiments are easier to clean in-place or disassemble for out-of-place cleaning, as described below.

<FIG> depict examples of internal attachment mechanisms for affixing an actuator to a hub according to an exemplary embodiment. <FIG> depicts an internal cross-sectional view of a configuration for an attachment point for an actuator <NUM> that includes several harborage points.

The actuator <NUM> has a wall <NUM> made of an elastomeric material that surrounds an internal void <NUM> configured to be filled with an inflation fluid. At the proximal end of the actuator <NUM>, a flared section <NUM> is placed flush with a mounting surface <NUM>, which may be (for example) an interface to a gripper to be mounted on a robotic arm. A collar <NUM> may be snapped around the flared section <NUM> and secured to the mounting surface <NUM>. For example, the collar <NUM> may be fixed to the mounting surface <NUM> using a fastening mechanism, such as screws or bolts. An inflation fluid supply path <NUM> extends through the mounting surface <NUM>, the collar <NUM>, and into the void <NUM> to supply inflation fluid to the actuator <NUM>.

At various locations in this configuration, harborage points <NUM> exist where chemical or biological material may accumulate and encourage bacterial growth. For example, harborage points <NUM> exist at the interface between the actuator <NUM> and the collar <NUM>, where sharp corners and crevices allow biological or chemical matter to accumulate. Similarly, harborage points <NUM> exist at the base of the collar <NUM>, where the collar <NUM> meets the mounting surface <NUM>.

Furthermore, the actuator <NUM> is configured to bend when inflated, deflated, or subjected to vacuum. As the actuator <NUM> bends (e.g., to the left or right in <FIG>), a gap forms between the internal face of the collar <NUM> and the external face of the flared section <NUM> (and any other portion of the actuator <NUM> surrounded by the collar <NUM>). This gap can quickly become filled with biological or chemical material and may include a number of harborage points. Moreover, this gap is difficult to access with cleaning tools while the actuator <NUM> is affixed to the mounting surface <NUM>, making in-place cleaning difficult or impossible.

An improved actuator configuration is depicted in <FIG>. In this exemplary embodiment, the actuator <NUM> is secured to the mounting surface <NUM> using a securing mechanism <NUM>. The securing mechanism <NUM> includes a central body <NUM> and one or more extensions <NUM> extending from the central body <NUM>. The extensions <NUM> are positioned above one or more ledges <NUM> formed in the wall <NUM> of the actuator <NUM>, with a gap existing to allow a fastening mechanism <NUM> (e.g., a bolt or screw) to be inserted through the mounting surface <NUM> and into a corresponding hole in the body <NUM> of the securing mechanism <NUM>. When the fastening mechanism <NUM> is tightened, the extensions <NUM> are drawn into the ledges <NUM> and compress the elastomeric material, forming a fluid-tight gasket and a circumferential seal with the mounting surface <NUM> around the proximal end of the actuator <NUM>. Preferably, the extensions <NUM> extend as far as possible in order to provide increased surface area for forming the gasket.

The securing mechanism <NUM> may be made of any suitable material, such as plastic or metal.

As can be seen in <FIG>, due to the absence of a collar the number of harborage points is reduced. In some embodiments, the portion of the flared section <NUM> that contacts the mounting surface <NUM> extends at substantially a <NUM>° angle away from the mounting surface <NUM>. As a result, the force exerted by the securing mechanism <NUM> pushes the flared portion <NUM> downward, which forms a relatively strong seal with the mounting surface <NUM> and reduces the area of the gap between the actuator <NUM> and the mounting surface <NUM>. Thus, harborage points are reduced in the system.

In some cases, if bacteria should accumulate at the interface between the actuator <NUM> and the mounting surface <NUM>, the actuator <NUM> may be removed from the mounting surface <NUM> by removing the fastening mechanism <NUM>, and the actuator <NUM> may be cleaned (e.g., in a dishwasher or an autoclave, if made of suitable materials). Because the mounting surface is typically flat, it is also relatively easy to clean.

In some embodiments, the securing mechanism <NUM> may include an inflation fluid passage allowing inflation fluid to pass through the securing mechanism. The inflation fluid passage may pass through the central body <NUM> along with the fastening mechanism <NUM>, or the inflation fluid passage and the fastening mechanism may be provided on different parts of the securing mechanism <NUM>, as shown in the configuration depicted in <FIG>. In this example, the inflation fluid passage <NUM> extends through the body <NUM> of the securing mechanism <NUM>. The securing mechanism <NUM> is provided with holes in the extensions <NUM> for receiving fastening mechanisms <NUM>. The ledges <NUM> in this example include a lower ledge situated below the extensions <NUM> and an upper ledge provided above the extensions <NUM>.

The fastening mechanisms <NUM> are inserted through the mounting surface <NUM> and through a hole in the lower ledge. The fastening mechanisms <NUM> then extend through the corresponding hole in the extensions <NUM>. In some embodiments, the fastening mechanisms <NUM> terminate in the extensions <NUM>; in others, the fastening mechanisms <NUM> penetrate the extensions <NUM> and extend into hardware overmolded into the upper ledge. When the fastening mechanisms are tightened, the lower ledge (and the upper ledge, if the fastening mechanism extends into it) is drawn tight with the extensions <NUM>, creating a fluid-tight gasket. Inflation fluid is supplied to the void <NUM> through the inflation fluid supply passage <NUM>. <FIG> depicts the securing mechanism <NUM> of this embodiment in more detail.

The securing mechanism <NUM> may be separate from the actuator <NUM>, or may be integral with the actuator <NUM>. For example, the securing mechanism <NUM> may be fabricated and then overmolded into the actuator <NUM> at the time of actuator fabrication.

<FIG> depicts an exemplary overmolded insert. In this case, the extensions <NUM> are provided between optional upper and lower ledges <NUM> (if the ledges <NUM> are not present, the securing mechanism <NUM> may be secured to the actuator wall <NUM> using, for example, surface treatments). The securing mechanism <NUM> receives the fastening mechanisms <NUM>, which pull the securing mechanism <NUM> towards the mounting surface <NUM>. Advantageously, an o-ring <NUM> may be provided around the outer bottom edge of the securing mechanism <NUM>. As the securing mechanism <NUM> is pulled tight against the o-ring <NUM>, the o-ring <NUM> provides a strong seal, reducing the gap between the securing mechanism <NUM> and the mounting surface <NUM>.

Furthermore, because of the shape of the relatively hard (as compared to the o-ring <NUM>) securing mechanism <NUM>, the securing mechanism <NUM> provides a hard stop for the fastening mechanism <NUM>. For example, the o-ring <NUM> may be silicon or an elastomer such as a flouropolymer elastomer, whereas the securing mechanism <NUM> may be food-safe plastic (e.g., PETE, delrin, polyethelene, or polypropylene) or metal (e.g., stainless steel with a grade of <NUM>, <NUM>, or <NUM>, or hard anodized aluminum). Because of the relatively hard or rigid nature of the securing mechanism <NUM>, there comes a point during the tightening of the fastening mechanisms <NUM> when the securing mechanism <NUM> cannot be drawn further towards the mounting surface <NUM>. This prevents the o-ring <NUM> from becoming over- or under-compressed and allows the securing mechanism <NUM> to be tuned (by varying the shape of the securing mechanism <NUM>, particularly the size and configuration of the gap which seats the o-ring <NUM>) to put a predetermined amount of force on the o-ring <NUM>.

Traditionally, external screws or bolts are used to fix an actuator or actuator assembly to a mounting surface <NUM>. These external fastening mechanisms create harborage points; the embodiments of <FIG> eliminate the external fastening mechanisms and replace them with internal fastening mechanisms to thereby reduce or eliminate these harborage points. Moreover, the interface between the actuator <NUM> and the mounting surface <NUM> may be held tight by the application of the fastening mechanisms <NUM>, reducing the gap between the actuator <NUM> and the mounting surface <NUM> and thereby reducing harborage points.

<FIG> depict further examples of hub and base assemblies for affixing a robotic gripper to a robotic arm without using external fastening mechanisms like bolts or screws. These assemblies may be used in conjunction with, or as an alternative to, the assemblies of <FIG>.

<FIG> depict the "twist-to-lock" nature of the hub/base assembly. The assembly includes one or more actuators <NUM> mounted into an actuator holder <NUM>, which may be formed of any suitable material such as plastic or metal. An overmolded elastomer layer <NUM> holds the actuators <NUM> on the actuator holder <NUM> and covers crevices, corners, and other features of the actuators <NUM> that could serve as harborage points. For example, as shown in <FIG>, the overmolded elastomer layer <NUM> may cover the proximal end of the actuator <NUM> up to the ridge on the most-proximal accordion extension. A gripper base <NUM> includes an inflation fluid chamber <NUM> for distributing inflation fluid to the actuators <NUM>. The gripper base <NUM> may be affixed or may be affixable to a robotic arm.

The actuator holder <NUM> is provided with one or more grooves <NUM> configured to mate with, and interlock with, corresponding extensions <NUM> on the gripper base <NUM>. As shown in <FIG>, the gripper assembly including the actuators <NUM>, the overmolded elastomer layer <NUM>, and the actuator holder <NUM> may be placed over the gripper base <NUM> and twisted to mate the extensions <NUM> into the grooves <NUM>. It should be noted that the interlocking mechanism may be reversed (e.g., with grooves <NUM> on the gripper base <NUM> and extensions <NUM> on the actuator holder <NUM>).

The use of an interlocking system allows for a screwless assembly, thereby removing potential harborage points. Moreover, this configuration allows the actuator holder <NUM> (along with the actuators <NUM> and the overmolded elastomer layer <NUM>) to be easily removed from the base <NUM> so that the base <NUM> may be easily cleaned out-of-place (i.e., when the base <NUM> has been removed from the robotic assembly).

<FIG> shows a close up exterior view of the assembled gripper system. As shown in <FIG>, the interface <NUM> at which the gripper base <NUM> mates to the actuator holder <NUM> includes smooth, curved surfaces. Thus, both the gripper base <NUM> and the actuator holder <NUM> do not require sharp corners at the interface <NUM>, which reduces harborage points and allows for simpler cleaning. Moreover, surfaces that may come into contact with chemical or biological material may have a smoothness value of at least <NUM> microinch, more preferably at least <NUM> microinches, and more preferably at least <NUM> microinches.

In general, throughout the application, and particularly in the case of internal angles, the angle between two surfaces may be at least <NUM>°. By making these internal angles relatively open, it is easier to clean these internal surfaces (e.g., with a brush or other tool). Similarly, when a curve is used, such as in the case of the interface <NUM>, the radius of the curve may be at least <NUM>/<NUM>", or more preferably <NUM>/<NUM>", or more preferably ¼", depending on the application.

<FIG> shows an internal view of the various components of the gripper system. An inflation fluid chamber <NUM> is provided in the gripper base <NUM> for supplying inflation fluid to the actuators <NUM>. An inflation fluid supply line <NUM> extends through the actuator holder <NUM>, through the overmolded elastomer <NUM>, and into the void <NUM> of the actuator <NUM>. Multiple inflation fluid supply lines <NUM> may be provided (e.g., one for each actuator <NUM> in the gripper assembly). The inflation fluid supply line <NUM> may be configured to mate with a corresponding interface on the inflation fluid chamber <NUM>, or may simply extend to a large opening on the inflation fluid chamber <NUM>. Because most of the opening of the chamber <NUM> will be covered by the actuator holder <NUM>, the only place for inflation fluid to escape will be into the inflation fluid supply lines <NUM> and into the actuators <NUM>.

As shown in <FIG>, the lower walls <NUM> inflation fluid chamber <NUM> have a curved shape and relatively wide openings. Moreover, the internal surfaces of the inflation fluid chamber <NUM> are relatively smooth (e.g., having a smoothness value of <NUM> microinches or more. These features reduce harborage points, allows cleaning fluid to drain out of the base after cleaning, more readily allows access by cleaning tools such as brushes, and provide for easier visual inspection to ensure that the inflation fluid chamber <NUM> has been sufficiently cleaned.

<FIG> depict a further example of a hub according to exemplary embodiments.

<FIG> depict a hub having an external fixturing mechanism <NUM>. As shown in <FIG>, a number of actuators <NUM> are secured together to form a gripper. The actuators <NUM> are inserted into a plate <NUM>, and the plate <NUM> is affixed to a robotic base <NUM> (e.g., a robotic arm or another structure to be fixed to a robotic arm). The plate <NUM> is secured to the robotic base <NUM> using a fixturing mechanism <NUM> (e.g., a screw or bolt), as shown in the closeup in <FIG>. The protruding fixturing mechanism <NUM> provides a number of harborage points for the gripper system.

In contrast, <FIG> depicts a perspective view of a hub having an internal fixturing mechanism. As can be seen in this example, the plate <NUM> presents a flat surface with no external screws. As shown in the cross-sectional view of <FIG>, an internal fixturing mechanism <NUM> is routed through an inflation fluid supply path <NUM>, and secures the plate <NUM> from the bottom.

Using the above-described hub assemblies (individually or in any combination), harborage points can be reduced or eliminated from the interconnections between the actuators/actuator holders and other parts of the system. Other harborage points may exist elsewhere, however. For example, inflation fluid may be supplied to a hub or other part of the system through an inflation fluid supply line such as a pneumatic fitting. <FIG> depict an example of a twist-lock inflation fluid supply line for reducing harborage points, according to an exemplary embodiment.

<FIG> provides a perspective view of a gripper including four actuators <NUM> connected to an actuator holder <NUM>. The actuator holder <NUM> may be mounted to a robotic arm.

As shown in the close-up of <FIG>, the actuator holder <NUM> includes a port <NUM> for receiving a fitting <NUM> for an inflation fluid supply line. The port <NUM> is configured to interconnect with the fitting <NUM> through a twist interlock system. In this example, the port <NUM> includes one or more fingers <NUM> that mate to one or more filleted slots <NUM> on the fitting <NUM>. The filleted slots <NUM> may be relatively wide or thick to allow for easy cleaning (thus more easily receiving a brush or other cleaning device as compared, for example, to screw threads). The internal bend <NUM> in the fingers <NUM> may may have a curved or teardrop cross-sectional profile, with a curve radius of at least <NUM>/<NUM>", or more preferably <NUM>/<NUM>", or more preferably ¼", in order to grip the filleted slots <NUM> while also remaining relatively easy to clean (as e.g., enabling easier access with a cleaning tools such as a brush).

One or more grooves <NUM> in the fitting <NUM>, each groove corresponding to a finger <NUM>, provide clearance allow the fitting <NUM> to be pushed onto the port <NUM> between the fingers <NUM>, as shown in <FIG>.

Once inserted onto the port <NUM>, the fitting <NUM> may be twisted to lock the fitting <NUM> into place, as shown in <FIG>. In an exemplary embodiment, the fitting <NUM> may be twisted about <NUM>° to allow for relatively simple assembly, although other degrees of twist (e.g., <NUM>° or <NUM>°) are also possible. In order to accommodate this amount of twisting, the grooves <NUM> may be shaped and configured to allow for a <NUM>° twist. Moreover, the grooves <NUM> may be shaped with an upward curve so that, as the fitting <NUM> is twisted, the fitting <NUM> undergoes linear displacement towards the hub <NUM>, thus pressing the fitting <NUM> into place against the hub and creating a fluid-tight seal.

<FIG> depict the twisting action in more detail. <FIG> depicts an external view of an unlocked fitting <NUM> from the front, while <FIG> depicts an internal cross-sectional view of the unlocked fitting <NUM> from the side. Note that, in the unlocked configuration, a gap <NUM> exists between the bottom of the fitting <NUM> and the hub <NUM>.

<FIG> depicts an external view of a locked port <NUM> (after twisting the port <NUM> to lock it in place) from the front, while <FIG> is an internal view of the locked port <NUM> from the side. By comparing <FIG> to Figure SH, it can be seen that twisting the port <NUM> results in an amount of linear displacement J which brings the bottom of the port <NUM> into contact with the hub <NUM>.

Alternatively or in addition, magnets may be used to secure an inflation fluid supply line to a hub. <FIG> depicts a magnetic attachment for an inflation fluid supply line, according to an exemplary embodiment. In this example, a hub <NUM> supports two actuators <NUM>. The hub <NUM> is provided with a first annular magnet <NUM> surrounding an inflation fluid supply path <NUM>. An inflation fluid supply line <NUM> for providing inflation fluid to the hub <NUM> includes a fitting <NUM> that incorporates a second annular magnet <NUM>. The first annular magnet <NUM> and the second annular magnet <NUM> may have opposite polarities so that, when brought into close proximity with one another, the first annular magnet <NUM> mates with the second annular magnet <NUM> and forms a fluid-tight seal. Because the magnets <NUM>, <NUM> are annular, inflation fluid flows through the hole in the magnets <NUM>, <NUM> and into the hub <NUM>, from which it can be distributed to the actuators <NUM>.

Next, innovations in actuator design and application for handling biological or chemical materials is discussed.

<FIG> depict an example of an actuator having reduced harborage points, according to an exemplary embodiment. <FIG> depicts a first actuator <NUM>, in which the ridges <NUM> of adjacent accordion extensions <NUM> are separated by relatively large distances r, and the troughs <NUM> are relatively deep (represented by the distance t). Both the ridges <NUM> and the troughs <NUM> have relatively sharp curves or sharp corners. Particularly in the case of the troughs <NUM>, which have interior angles into which it may be difficult to place a brush or cleaning mechanism, these curves and corners create a number of harborage points <NUM>.

<FIG> depicts a modified actuator <NUM>. In this example, the ridges <NUM> of adjacent accordion extensions are further apart (separated by a relatively larger distance r'), while the troughs <NUM> are more shallow (represented by the distance t', which is less than t). The ridges <NUM> and the troughs <NUM> have more rounded edges, with gentler curves.

As a result, edges on the actuator <NUM> are smoothed, reducing bacterial harborage points. Moreover, clearings on the actuator <NUM> are expanded, which makes it easier to clean the actuator <NUM> with a brush, pad, solution, etc. to remove bacteria and food debris from the actuator <NUM>.

To further reduce harborage points, the accordion extensions <NUM> may be covered entirely so that the non-gripping side of the actuator presents a smooth or flat surface. <FIG> depict an accordion cover for a soft actuator, according to an exemplary embodiment.

<FIG> depicts an actuator <NUM> having a plurality of accordion extensions <NUM>. A most-proximal accordion extension includes a starting ridge <NUM>, and a most-distal accordion extension includes an ending ridge <NUM>.

To eliminate or reduce harborage points between or on the accordion extensions <NUM>, the accordion extensions <NUM> may be covered with an accordion cover <NUM>, as shown in <FIG>. The accordion cover <NUM> may be formed of a highly extensible elastomer configured to readily flex when the actuator <NUM> is inflated with inflation fluid or subjected to a vacuum. Thus, the accordion cover <NUM> does not hinder the expansion or contraction of the actuator <NUM>.

The accordion cover <NUM> may be removable, or may be integrated with the actuator <NUM>. For example, the accordion cover <NUM> may be an elastomer that fully encases the accordion extensions <NUM> and fills in the areas between the accordion extensions <NUM>.

As shown in the internal cross-sectional view of <FIG>, the accordion cover <NUM> may extend from the starting ridge <NUM> to the ending ridge <NUM>. In other embodiments, the accordion cover <NUM> may extend beyond the starting ridge <NUM> and/or the ending ridge <NUM>. Alternatively or in addition, the accordion cover <NUM> may cover some, but not all, of the accordion extensions <NUM>.

The gripping surface of the actuator <NUM> may also be supplemented. For example, <FIG> depicts an example of an overmolded soft gripping pad <NUM>, according to an exemplary embodiment. The soft gripping pad <NUM> is provided on at least a portion of the gripping surface of the actuator <NUM>. The soft gripping pad <NUM> may be integral with the actuator <NUM>, or may be a separate part that is affixed to the actuator <NUM> (e.g., using elastomeric bands), allowing the pad <NUM> to be removed for separate cleaning.

The soft gripping pad <NUM> may be formed of a soft elastomeric material (e.g., an elastomeric material that is relatively more flexible, pliable, or yielding to a force than the elastomeric material from which the actuator <NUM> is formed) and may allow the actuator <NUM> to manipulate delicate objects, such as tomatoes, without bruising the objects' surface.

An interface <NUM> between the gripping pad <NUM> and the base <NUM> of the actuator <NUM> is curved to reduce or eliminate a potential harborage point.

According to the invention, the gripping surface of the actuator <NUM> is provided with other types of texturing that are readily cleaned. <FIG> depict cross-sectional side views of actuators having inflatable texturing surfaces, according to the invention.

<FIG> depicts an actuator <NUM> in an uninflated state. The actuator <NUM> includes a wall <NUM> surrounding a void <NUM> into which inflation fluid may be supplied. On the base <NUM> of the actuator, the thickness of the wall <NUM> varies between alternating thick-walled portions <NUM> and thin-walled portions <NUM>. The thin-walled portions <NUM> have a thickness that is relatively smaller than the thick-walled portions <NUM>.

In the uninflated state, the base <NUM> of the actuator <NUM> is flat. Thus, when not inflated, the actuator exhibits fewer or no harborage points on the base <NUM> that forms the gripping surface, and can be readily cleaned.

However, when inflated (as shown in <FIG>), the inflation fluid enters the void <NUM> and presses against the external walls <NUM> of the actuator. Because the thin-walled portions <NUM> are less rigid or resistant to inflation than the thick-walled portions <NUM>, the thin-walled portions <NUM> may bow out, creating a textured base <NUM>. Thus, the actuator <NUM> may more readily grip an object. When the inflation fluid is removed, the thin-walled portions <NUM> return to their flat configuration and the base <NUM> becomes smooth again, for easy cleaning.

Note that <FIG> depicts the base <NUM> in a textured configuration (implying the presence of inflation fluid in the void <NUM>), although the actuator <NUM> is in an unbent configuration. In real-world scenarios, applying inflation fluid would typically cause the actuator <NUM> to bend, as shown in <FIG>; the bending is not shown in <FIG> for ease of understanding.

Instead of the thin-walled portions <NUM> and the thick-walled portions <NUM>, the base <NUM> may be formed of alternating materials of different types that are more or less resistant to expansion upon inflation. When inflated, the portions of the base <NUM> with less resistant materials will expand more than the portions of the base <NUM> with more resistant materials, creating a textured surface.

Moreover, a similar effect may be achieved by applying a vacuum instead of inflation fluid. For example, the thin-walled portions <NUM> may be configured to be in an extended configuration by default. Upon application of a vacuum, the thin-walled portions <NUM> may bow inwards, creating a flat surface.

<FIG> depicts an alternate configuration in which the texturing of the base may be applied independently of inflation of the actuator <NUM>. In this example, an internal wall <NUM> separates the void <NUM> into two chambers. A first chamber <NUM> exists in the area adjacent to the base <NUM>, while a second chamber <NUM> fills the remainder of the actuator <NUM>. The two chambers <NUM>, <NUM> may be inflated independently of one another. When the first chamber <NUM> is filled, the thin-walled portions <NUM> bow outwards, creating a textured surface on the base <NUM>. When the second chamber <NUM> is filled, the actuator <NUM> bends according to its inflation profile in order to grasp a target.

In addition to providing systems that reduce harborage points, it may also be useful when working with biological or chemical materials to use special purpose actuators well-suited to contexts in which these materials are often handled.

For example, <FIG> depict an exemplary tapered soft actuator <NUM> comprising a taper according to the invention. <FIG> depicts a perspective view of the tapered actuator <NUM>, while <FIG> depict side, front, and bottom views, respectively. As shown in these Figures, the actuator <NUM> tapers both in thickness (t) and in breadth (b) from the proximal end <NUM> to the distal end <NUM>.

It is noted that the tapered actuator <NUM> need not necessarily taper uniformly across or along the actuator <NUM>. For example, different effects may be achieved by utilizing different relative degrees of taper along the width, length, or wall thickness of the actuator, or by tapering the amplitude of respective accordions, resulting in an alteration of lateral actuator stability, axial finger stability, gradient changes in expansion when actuated, or gradient changes in curvature response when actuated, respectively.

A tapered actuator <NUM> is exceptionally stable in torsion, has a large surface area for friction-dominated grasp, maintains small and dexterous finger tips for manipulation of small items, and delivers relatively higher grasping force per the same pressure as compared to an actuator having a homogeneous cross-section. This allows tapered actuators <NUM> to be deployed in tandem with each other, for example in a circular or rectangular pattern, for precision handling of a range of object sizes and weights. Moreover, tapered actuators <NUM> are particularly well-suited to manipulating wet, slippery, oddly/irregularly shaped, and cluttered food items (e.g., food items in a heap or in form fitting packaging).

Moreover, a tapered actuator <NUM> may be better able to navigate cluttered environments as compared to a non-tapered actuator (e.g., bushels of unstructured fruit or produce).

For example, <FIG> depict an exemplary spherically enveloping gripper employing skewed actuators <NUM>. These leaf-shaped skewed actuators <NUM> are well-suited to fully enclosing fragile objects. <FIG> depicts a perspective view of a gripper employing four skewed actuators <NUM>, whereas <FIG> depict front, side, and bottom views of the a single actuator <NUM>, respectively.

As can be seen in <FIG> (bottom view), the skewed actuator <NUM> includes a plurality of skewed internal chambers <NUM> for receiving inflation fluid. The skewed chambers <NUM> have a teardrop or other skewed shape that expands from a relatively narrow region r<NUM> to a relatively wider region r<NUM>. The relatively narrow r<NUM> region may be disposed close to the center of the skewed actuator <NUM> (e.g., the portion of the internal chamber <NUM> that is closest to the centerline A-A, as shown in <FIG>), whereas the relatively wider region r<NUM> may be disposed towards the external edge of the skewed actuator <NUM>, away from the centerline A-A.

The skewed actuators <NUM> have a number of characteristics.

First, each skewed actuator <NUM> has multiple degrees of freedom when actuated. In other words, the skewed actuators <NUM> bend about its major axis (e.g., around the central axis to curve in the circumferential direction as depicted in <FIG>) as well as across its minor axis (in the axial direction of <FIG>).

Second, the skewed actuator <NUM> has a relatively broad leaf-like shape which tends to form a completely enclosing sphere when matched with other tapered actuators <NUM> in a circularly- or rectangularly- patterned layout.

Third, the tapered design of the skewed actuator <NUM> improves stability and increases grasping force. These properties make such an actuator well-suited to manipulating, for example, many types of roughly round fruits and vegetables. Because the skewed actuator <NUM> encompasses an object (referred to herein as providing a "caging" grip), the skewed actuator <NUM> may allow the skewed actuator <NUM> to, for example, pick delicate fruit from a tree (e.g., apples) or vine (e.g., tomatoes or grapes). A task such as fruit picking may require a stronger grip than, for example, simply moving picked fruit from one location to another. Because a stronger grip is required, if the grip is focused in a few locations (e.g., at the fingertips of the actuators), then the fruit can be bruised or damaged. By applying a caging grip, this force may be distributed over a larger surface area, which improves the chances of picking the fruit without bruising it.

Objects may be fully encompassed or encapsulated by other methods as well. For example, <FIG> depict webbing <NUM> applied between actuators <NUM> in order to allow the actuators <NUM> to fully encapsulate objects. The webbing <NUM> may be formed of relatively extensible elastomeric material to allow the webbing to expand while the actuators <NUM> are in an open state (<FIG>), while maintaining a reasonable amount of tension when the actuators <NUM> are in a closed state (<FIG>), so as to maintain the grasped object within the webbing <NUM>. The use of webbing <NUM> allows for increased surface area contact between a gripper and an object.

In some cases, an object to be grasped may be located deep within a container, such as a bin, where the object may be difficult to reach. <FIG> depict exemplary extend-and-grasp actuators suitable for these and other applications.

<FIG> depicts an inflated extensible actuator <NUM>, while <FIG> depicts an uninflated extensible actuator <NUM>. The extensible actuator <NUM> includes a number of accordion extensions <NUM> divided into two sections. A full accordion section <NUM> includes accordion extensions <NUM> that extend around a full diameter of the extensible actuator <NUM>. A partial accordion section <NUM> includes accordion extensions <NUM> that extend only part way around the diameter of the extensible actuator <NUM>. The full accordion section <NUM> may include accordion extensions <NUM> at a higher frequency or rate than the partial accordion section <NUM>.

As a result, when the extensible actuator <NUM> is inflated, at a relatively low inflation pressure the full accordion section <NUM> begins to extend (under a relatively small amount of force). This causes the extensible actuator <NUM> to extend linearly, with a relatively small degree of curvature at the distal end, which allows the extensible actuator <NUM> to (for example) reach into a bin or container that might otherwise be blocked by the actuator's hub assembly <NUM>. At relatively high inflation pressure, the partial accordion section <NUM> exhibits increasing degrees of curvature, allowing the extended actuator to grasp an object.

In further embodiments, an actuator may employ a special geometry in order to better grasp particular targets. For example, <FIG> depict an actuator incorporating a hook, according to an exemplary embodiment.

As shown in <FIG>, the hooked actuator <NUM> includes a curved protrusion <NUM> at its distal end in the shape of a hook. Accordingly, when the hooked actuator <NUM> is inflated in order to grasp an object (<FIG>, showing varying degrees of inflation pressure), the curved protrusion <NUM> of the hooked actuator <NUM> extends underneath the object to be grasped (<FIG>), subsequently pulling the object inward (<FIG>). This allows for greater contact with the gripping surface of the hooked actuator <NUM>, and improves the stability of the object while it is being moved or manipulated.

Regardless of the type of actuator used, it may be helpful in some scenarios to increase the opening between actuators prior to grasping a target. For example, when grasping a large object, a relatively large opening angle may be called for. When grasping a small object, a relatively small opening angle may be called for.

To achieve different degrees of opening, vacuum may be applied to the actuator (e.g., instead of filling the actuator with an inflation fluid, ambient fluid in the actuator may be removed from the actuator). For instance, <FIG> depict examples of different degrees of vacuum applied to actuators <NUM> to modify the actuators' opening profile. <FIG> depicts a relatively large opening angle achieved by applying a relatively large amount of vacuum to the actuators <NUM>. <FIG> depicts a relatively small opening angle achieved by applying a relatively smaller (or no) amount of vacuum.

In some embodiments, a robotic system is configured to provide a precise, predetermined amount of vacuum to one or more actuators <NUM>. The predetermined amount may be selected in an amount that accommodates the environment in which the actuator <NUM> is intended to operate and the size or configuration of the object that the actuator <NUM> is intended to grasp. For example, if too little vacuum is applied, the actuator <NUM> will not open sufficiently to grasp the target. On the other hand, if too much vacuum is applied, the actuator <NUM> will open more widely than is necessary, which may cause the actuator <NUM> to collide with the container holding the target object and/or other objects near the target object. This is especially true in cluttered environments. By providing a predetermined amount of vacuum, the actuator <NUM> can be opened enough to allow the target object to be grasped while still providing sufficient space between the actuator and adjacent objects or containers.

In a further embodiment, the system may be made easier to clean by applying a food-safe or medically-safe wrapping around some or all of a robotic system. For example, <FIG> depict an exemplary disposable wrapping for a robotic system <NUM>.

As shown in <FIG>, the robotic system <NUM> includes a robotic arm <NUM> to which a hub <NUM> is mounted. Actuators <NUM> are connected to the hub <NUM>. A disposable wrapping <NUM>, which is sized and shaped to correspond to the robotic system <NUM>, is provided around the robotic system <NUM>.

The disposable wrapping <NUM> is sized and shaped to be relatively loose when the actuators <NUM> are in an uninflated state (<FIG>) and relatively tighter (without risking breakage of the disposable wrapping <NUM>) when the actuators <NUM> are in an inflated state (<FIG>). For example, the size and shape of the bag may be selected so as to provide a predetermined amount of slack when the actuators <NUM> are uninflated. When the actuators <NUM> are inflated, the slack is reduced and the actuators <NUM> may grip a target object. Alternatively or in addition, the disposable wrapping <NUM> may be formed of elastic materials in order to allow the disposable wrapping <NUM> to compensate for inflation of the actuators <NUM>.

It is noted that the wrapping <NUM> need not necessarily be disposable. In some embodiments, the wrapping <NUM> may be capable of removal for cleaning, and may be re-used once cleaned.

Claim 1:
A soft actuator (<NUM>) comprising:
an elastomeric body that extends from a proximal end (<NUM>) to a distal end (<NUM>), the elastomeric body:
surrounding a void (<NUM>) configured to receive an inflation fluid,
comprising a plurality of accordion extensions (<NUM>), and
being tapered from the proximal end (<NUM>) to the distal end (<NUM>) in a breadth direction and a thickness direction; wherein
the soft actuator (<NUM>) comprises a gripping surface on a base (<NUM>) of the soft actuator (<NUM>), characterized in that the gripping surface is configured to extend to create a textured surface on the base (<NUM>) when the actuator (<NUM>) is in an inflated state, and configured to retract to create a smooth surface when the actuator (<NUM>) is not in an inflated state.