SOFT ROBOTIC TOOLS WITH SEQUENTIALLY UNDERACTUATED MAGNETORHEOLOGICAL FLUIDIC JOINTS

A soft robotic tool may include a plurality of rigid links, a plurality of magnetorheological fluid soft joints, and a plurality of tendons. The rigid links may be disposed in series. Each magnetorheological fluid soft joint may be disposed between a pair of the rigid links. Each magnetorheological fluid soft joint may include a capsule containing a magnetorheological fluid, and an inductive coil disposed around the capsule. The tendons may extend along a length of the soft robotic tool. Each tendon may be attached to each of the rigid links.

FIELD OF THE DISCLOSURE

The present disclosure relates generally to robotics and more particularly to soft robotic tools with sequentially underactuated magnetorheological fluidic joints.

BACKGROUND OF THE DISCLOSURE

Robotic tools may be used in various applications for performing certain tasks or procedures either autonomously or under the guidance of a human operator. For example, in the medical field, a trained clinician may use robotic tools to perform a medical procedure, such as minimally invasive surgery (MIS). In recent years, MIS techniques have become increasingly popular in view of benefits including, for example, smaller incisions, reduced recovery time, lower medical costs, and reduced infection risks. A robotic platform for MIS typically may include one or more surgical tools, navigation systems, and imaging systems configured for performing a desired procedure. An MIS procedure generally may include inserting a flexible tube mounted with one or more tools into the body of a patient and navigating an anatomical pathway to reach buried, diseased, or injured tissue. In some instances, the anatomical pathway may be complex, including non-linear portions, multiple branches, and/or changes in diameter that must be navigated to reach the target tissue. Challenges in navigating such a complex pathway often may necessitate repeated re-insertion and re-positioning of the flexible tube and associated tools, which takes time away from immediately treating the target tissue and potentially may damage tissue along the pathway.

Certain soft robotic tools have utilized shape memory alloys to manipulate the shape of the tool and facilitate navigation of complex pathways. However, such tools generally may not be ideal for use in surgical applications due to low repeatability, slow response, and relatively high temperatures required for changing from one shape to another through material memory (i.e., transitioning the shape memory alloys from the martensite phase to the austenite phase). Other soft robotic tools have used dielectric actuators for manipulating the shape of the tool. Deformation of dielectric actuators, however, generally may require relatively high voltages that are not suitable for a surgical tool. Still other soft robotic tools have implemented granular jamming mechanisms to manipulate the shape of the tool and provide variable stiffness. However, granular jamming mechanisms generally may be bulky and noisy and may have low force density, making such mechanisms undesirable for use in surgical applications.

A need therefore remains for improved soft robotic tools for navigating complex pathways, such as complex anatomical pathways in MIS applications, which allow the tool to be manipulated to reach a target location simply, quickly, and in one smooth motion.

SUMMARY OF THE DISCLOSURE

The present disclosure provides soft robotic tools, robotic systems, and related methods for using such tools and systems to navigate complex pathways. In one aspect, a soft robotic tool is provided. In one embodiment, a soft robotic tool may include a plurality of rigid links, a plurality of magnetorheological fluid soft joints, and a plurality of tendons. The rigid links may be disposed in series. Each magnetorheological fluid soft joint may be disposed between a pair of the rigid links. Each magnetorheological fluid soft joint may include a capsule containing a magnetorheological fluid, and an inductive coil disposed around the capsule. The tendons may extend along a length of the soft robotic tool. Each tendon may be attached to each of the rigid links.

In some embodiments, each magnetorheological fluid soft joint may be configured to assume an off state when no magnetic field is generated by the inductive coil and to assume an on state when a magnetic field is generated by the inductive coil. In some embodiments, each magnetorheological fluid soft joint may be configured to allow articulation of the soft robotic tool about the magnetorheological fluid soft joint when the magnetorheological fluid soft joint is in the off state, and each magnetorheological fluid soft joint may be configured to inhibit articulation of the soft robotic tool about the magnetorheological fluid soft joint when the magnetorheological fluid soft joint is in the on state.

In some embodiments, the rigid links may be formed of a polymeric material. In some embodiments, the polymeric material of the rigid links may include acrylonitrile butadiene styrene or polylactic acid. In some embodiments, the rigid links may be formed of a metallic material. In some embodiments, the rigid links may be formed of a ceramic material. In some embodiments, the capsule may be formed of a polymeric material. In some embodiments, the polymeric material of the capsule may include silicone. In some embodiments, the magnetorheological fluid may include a dispersion of magnetic particles in a non-conductive, non-magnetic carrier fluid. In some embodiments, the magnetic particles may include iron particles, and the carrier fluid may include silicone oil. In some embodiments, the magnetorheological fluid also may include one or more surfactants. In some embodiments, the one or more surfactants may include an alkanethiol or a mercaptosilane. In some embodiments, the inductive coil may be encapsulated in a biocompatible polymer. In some embodiments, the tendons may include wires.

In some embodiments, the plurality of tendons may include a first tendon and a second tendon. In some embodiments, the first tendon and the second tendon may extend parallel to one another. In some embodiments, the rigid links may define a first tendon routing pathway and a second tendon routing pathway, with the first tendon extending along the first tendon routing pathway, and with the second tendon extending along the second tendon routing pathway. In some embodiments, the plurality of rigid links may include a first rigid link and a second rigid link, with the first rigid link defining a first portion of the first tendon routing pathway and a first portion of the second tendon routing pathway, and with the second rigid link defining a second portion of the first tendon routing pathway and a second portion of the second tendon routing pathway. In some embodiments, the first portion of the first tendon routing pathway may extend in a linear manner along a length of the first rigid link, and the first portion of the second tendon routing pathway may extend in a linear manner along the length of the first rigid link. In some embodiments, the first portion of the first tendon routing pathway may extend parallel to a longitudinal axis of the first rigid link, and the first portion of the second tendon routing pathway may extend parallel to the longitudinal axis of the first rigid link. In some embodiments, the second portion of the first tendon routing pathway may extend in a linear or non-linear manner along a length of the second rigid link, and the second portion of the second tendon routing pathway may extend in a linear or non-linear manner along the length of the second rigid link. In some embodiments, the second portion of the first tendon routing pathway may be curved along the length of the second rigid link such that a first end of the second portion of the first tendon routing pathway is circumferentially offset from a second end of the second portion of the first tendon routing pathway with respect to a longitudinal axis of the second rigid link, and the second portion of the second tendon routing pathway may be curved along the length of the second rigid link such that a first end of the second portion of the second tendon routing pathway is circumferentially offset from a second end of the second portion of the second tendon routing pathway with respect to the longitudinal axis of the second rigid link. In some embodiments, the first end of the second portion of the first tendon routing pathway may be circumferentially offset from the second end of the second portion of the first tendon routing pathway by 90 degrees, and the first end of the second portion of the second tendon routing pathway may be circumferentially offset from the second end of the second portion of the second tendon routing pathway by 90 degrees. In some embodiments, the plurality of rigid links also may include a third rigid link, with the third rigid link defining a third portion of the first tendon routing pathway and a third portion of the second tendon routing pathway. In some embodiments, the plurality of tendons also includes a third tendon.

In some embodiments, the plurality of magnetorheological fluid soft joints may include a first magnetorheological fluid soft joint and a second magnetorheological fluid soft joint, with the first tendon and the second tendon being configured to bend the first magnetorheological fluid soft joint in a first bending plane, and with the first tendon and the second tendon being configured to bend the second magnetorheological fluid soft joint in a second bending plane transverse to the first bending plane. In some embodiments, the second bending plane may be orthogonal to the first bending plane. In some embodiments, the plurality of rigid links may include a first rigid link, with the first magnetorheological fluid soft joint being connected to a first end of the first rigid link, and with the second magnetorheological fluid soft joint being connected to a second end of the first rigid link. In some embodiments, the plurality of magnetorheological fluid soft joints may include a first magnetorheological fluid soft joint and a second magnetorheological fluid soft joint, with the first tendon and the second tendon being configured to bend the first magnetorheological fluid soft joint in a bending plane, and with the first tendon and the second tendon being configured to bend the second magnetorheological fluid soft joint in the bending plane. In some embodiments, the plurality of magnetorheological fluid soft joints may include a first magnetorheological fluid soft joint, a second magnetorheological fluid soft joint, and a third magnetorheological fluid soft joint. In some embodiments, the plurality of rigid links may include a first rigid link, a second rigid link, and a third rigid link, with each tendon being movably attached to each of the first rigid link and the second rigid link, and with each tendon being fixedly attached to the third rigid link. In some embodiments, the first rigid link may be disposed at a proximal end of the soft robotic tool, the third rigid link may be disposed at a distal end of the soft robotic tool, and the second rigid link may be disposed between the first rigid link and the third rigid link. In some embodiments, each tendon may be movably attached to each of the first rigid link and the second rigid link by passing through respective apertures defined by the first rigid link and the second rigid link.

In another aspect, a soft robotic tool is provided. In one embodiment, a soft robotic tool may include a first rigid link, a second rigid link, a magnetorheological fluid soft joint, a first tendon, and a second tendon. The magnetorheological fluid soft joint may be disposed between the first rigid link and the second rigid link. The magnetorheological fluid soft joint may include a capsule containing a magnetorheological fluid, and an inductive coil disposed around the capsule. The first tendon may be attached to the first rigid link and the second rigid link. The second tendon may be attached to the first rigid link and the second rigid link.

In some embodiments, the magnetorheological fluid soft joint may be configured to assume an off state when no magnetic field is generated by the inductive coil and to assume an on state when a magnetic field is generated by the inductive coil. In some embodiments, the magnetorheological fluid soft joint may be configured to allow articulation of the soft robotic tool about the magnetorheological fluid soft joint when the magnetorheological fluid soft joint is in the off state, and the magnetorheological fluid soft joint may be configured to inhibit articulation of the soft robotic tool about the magnetorheological fluid soft joint when the magnetorheological fluid soft joint is in the on state. In some embodiments, a first end of the magnetorheological fluid soft joint may be connected to the first rigid link, and a second end of the magnetorheological fluid soft joint may be connected to the second rigid link. In some embodiments, the first rigid link may define a first portion of a first tendon routing pathway and a first portion of a second tendon routing pathway, the second rigid link may define a second portion of the first tendon routing pathway and a second portion of the second tendon routing pathway, the first tendon may extend along the first tendon routing pathway, and the second tendon may extend along the second tendon routing pathway. In some embodiments, the first tendon may be movably attached to the first rigid link and fixedly attached to the second rigid link, and the second tendon may be movably attached to the first rigid link and fixedly attached to the second rigid link. In some embodiments, the second rigid link may be disposed at a distal end of the soft robotic tool. In some embodiments, the first tendon may be movably attached to the first rigid link by passing through a first aperture defined by the first rigid link, and the second tendon may be movably attached to the first rigid link by passing through a second aperture defined by the first rigid link.

In still another aspect, a robotic system is provided. In one embodiment, a robotic system may include a soft robotic tool and an actuation module. The soft robotic tool may include a plurality of rigid links, a plurality of magnetorheological fluid soft joints, and a plurality of tendons. The rigid links may be disposed in series. Each magnetorheological fluid soft joint may be disposed between a pair of the rigid links. Each magnetorheological fluid soft joint may include a capsule containing a magnetorheological fluid, and an inductive coil disposed around the capsule. The tendons may extend along a length of the soft robotic tool. Each tendon may be attached to each of the rigid links. The actuation module may include a motor and a plurality of actuators. The motor may be configured to advance and retract the soft robotic tool relative to the actuation module. The actuators may be configured to drive the tendons. Each actuator may be coupled to one of the tendons.

In some embodiments, each magnetorheological fluid soft joint may be configured to assume an off state when no magnetic field is generated by the inductive coil and to assume an on state when a magnetic field is generated by the inductive coil. In some embodiments, each magnetorheological fluid soft joint may be configured to allow articulation of the soft robotic tool about the magnetorheological fluid soft joint when the magnetorheological fluid soft joint is in the off state, and each magnetorheological fluid soft joint may be configured to inhibit articulation of the soft robotic tool about the magnetorheological fluid soft joint when the magnetorheological fluid soft joint is in the on state.

In some embodiments, the actuation module also may include a motor controller configured to control activation of the motor for advancing and retracting the soft robotic tool. In some embodiments, the actuation module also may include an actuator controller configured to control activation of the actuators for driving the tendons to articulate the soft robotic tool about the magnetorheological fluid soft joints. In some embodiments, the actuator controller may be configured to cause only one of the tendons to be pulled while a remainder of the tendons are maintained in a slack state. In some embodiments, the actuation module also includes a plurality of current controllers in communication with the inductive coils of the magnetorheological fluid soft joints, with each current controller being configured to control a strength of a magnetic field generated by one of the inductive coils. In some embodiments, the current controllers may be configured to cause only one of the magnetorheological fluid soft joints to assume the off state while a remainder of the magnetorheological fluid soft joints assume the on state. In some embodiments, the robotic system also may include one or more surgical tools mounted to the soft robotic tool. In some embodiments, the one or more surgical tools may include a camera, a cautery head, or an electrode. In some embodiments, the plurality of rigid links may include a first rigid link, a second rigid link, and a third rigid link, the plurality of tendons may include a first tendon and a second tendon, the first tendon may be movably attached to each of the first rigid link and the second rigid link, the first tendon may be fixedly attached to the third rigid link, the second tendon may be movably attached to each of the first rigid link and the second rigid link, and the second tendon may be fixedly attached to the third rigid link. In some embodiments, the first rigid link may be disposed at a proximal end of the soft robotic tool, the third rigid link may be disposed at a distal end of the soft robotic tool, and the second rigid link may be disposed between the first rigid link and the third rigid link. In some embodiments, the first tendon may be movably attached to each of the first rigid link and the second rigid link by passing through respective apertures defined by the first rigid link and the second rigid link, and the second tendon may be movably attached to each of the first rigid link and the second rigid link by passing through respective apertures defined by the first rigid link and the second rigid link.

In another aspect, a soft robotic tool is provided. In one embodiment, a soft robotic tool may include a plurality of rigid links, and a plurality of magnetorheological fluid soft joints. The rigid links may be disposed in series. Each magnetorheological fluid soft joint may be disposed between a pair of the rigid links. Each magnetorheological fluid soft joint may include a capsule containing a magnetorheological fluid, and an inductive coil disposed around the capsule.

In some embodiments, each magnetorheological fluid soft joint may be configured to assume an off state when no magnetic field is generated by the inductive coil and to assume an on state when a magnetic field is generated by the inductive coil. In some embodiments, each magnetorheological fluid soft joint may be configured to allow articulation of the soft robotic tool about the magnetorheological fluid soft joint when the magnetorheological fluid soft joint is in the off state, and each magnetorheological fluid soft joint may be configured to inhibit articulation of the soft robotic tool about the magnetorheological fluid soft joint when the magnetorheological fluid soft joint is in the on state.

In some embodiments, the rigid links may be formed of a polymeric material. In some embodiments, the polymeric material of the rigid links may include acrylonitrile butadiene styrene or polylactic acid. In some embodiments, the rigid links may be formed of a metallic material. In some embodiments, the rigid links may be formed of a ceramic material. In some embodiments, the capsule may be formed of a polymeric material. In some embodiments, the polymeric material of the capsule may include silicone. In some embodiments, the magnetorheological fluid may include a dispersion of magnetic particles in a non-conductive, non-magnetic carrier fluid. In some embodiments, the magnetic particles may include iron particles, and the carrier fluid may include silicone oil. In some embodiments, the magnetorheological fluid also may include one or more surfactants. In some embodiments, the one or more surfactants may include an alkanethiol or a mercaptosilane. In some embodiments, the inductive coil may be encapsulated in a biocompatible polymer.

The detailed description is set forth with reference to the accompanying drawings. The drawings are provided for purposes of illustration only and merely depict example embodiments of the disclosure. The drawings are provided to facilitate understanding of the disclosure and shall not be deemed to limit the breadth, scope, or applicability of the disclosure. The use of the same reference numerals indicates similar, but not necessarily the same or identical components. Different reference numerals may be used to identify similar components. Various embodiments may utilize elements or components other than those illustrated in the drawings, and some elements and/or components may not be present in various embodiments. The use of singular terminology to describe a component or element may, depending on the context, encompass a plural number of such components or elements and vice versa.

DETAILED DESCRIPTION OF THE DISCLOSURE

In the following description, specific details are set forth describing some embodiments consistent with the present disclosure. Numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art that some embodiments may be practiced without some or all of these specific details. The specific embodiments disclosed herein are meant to be illustrative but not limiting. One skilled in the art may realize other elements that, although not specifically described here, are within the scope and the spirit of this disclosure. In addition, to avoid unnecessary repetition, one or more features shown and described in association with one embodiment may be incorporated into other embodiments unless specifically described otherwise or if the one or more features would make an embodiment non-functional. In some instances, well known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

Embodiments of soft robotic tools, robotic systems, and related methods for using such tools and systems to navigate complex pathways are provided. As described herein, the soft robotic tools advantageously may be well suited for navigating complex anatomical pathways in MIS applications. In one embodiment, a soft robotic tool may include a plurality of rigid links disposed in series, a plurality of magnetorheological fluid soft joints each disposed between a pair of the rigid links, and a plurality of tendons each attached to each of the rigid links. Each magnetorheological fluid soft joint may include a capsule containing a magnetorheological fluid, and an inductive coil disposed around the capsule. When no magnetic field is generated by the inductive coil, the magnetorheological fluid soft joint may assume an unlocked or off state in which the soft robotic tool may be articulated about the magnetorheological fluid soft joint. For example, one of the tendons may be pulled to bend the magnetorheological fluid soft joint in a predefined bending plane. When a magnetic field is generated by the inductive coil, the magnetorheological fluid soft joint may assume a locked or on state in which the soft robotic tool is inhibited from articulating about the magnetorheological fluid soft joint. During use of the soft robotic tool, one of the magnetorheological fluid soft joints may be unlocked while a remainder of the magnetorheological fluid soft joints are locked, such that one of the tendons may be pulled to articulate the soft robotic tool about the unlocked magnetorheological fluid soft joint. The magnetorheological fluid soft joints may be sequentially unlocked and locked, and the tendons may be selectively pulled to bend, aim, and orient the soft robotic tool as desired to facilitate navigation of complex pathways. In this manner, the magnetorheological fluid soft joints may function as an embedded switching mechanism, with the magnetorheological fluid controlling mobility of the magnetorheological fluid soft joints, while the tendons control motion actuation of the soft robotic tool. Ultimately, the soft robotic tool described herein may overcome the above-described limitations associated with use of existing soft robotic tools to navigate complex anatomical pathways. In particular, the magnetorheological fluid soft joints may provide a compact, responsive means for enabling and disabling mobility of the respective joints, while the tendons provide an accurate, repeatable means for precisely controlling motion actuation of the soft robotic tool.

Although the soft robotic tools, robotic systems, and related methods provided herein may be described as being particularly useful for surgical applications, it will be appreciated that the use of such tools, systems, and methods is not limited to surgical applications. To the contrary, the soft robotic tools, robotic systems, and related methods described herein advantageously may be used in various non-surgical and non-medical applications in which navigation of complex pathways including non-linear portions, multiple branches, and/or changes in diameter, such as changes from relatively large diameters to relatively small diameters, is desirable.

Referring now toFIG. 1A, a soft robotic tool100(also referred to herein as a “robotic surgical tool,” a “robotic tool” or simply a “tool”) in accordance with one or more embodiments of the disclosure is depicted. The soft robotic tool100is configured for navigating complex pathways. For example, the soft robotic tool100may be used for navigating complex anatomical pathways, such as in MIS applications. The soft robotic tool100may be formed as an elongated structure having a proximal end102and a distal end104disposed opposite one another along a longitudinal axis of the tool100. Although the soft robotic tool100is depicted in a linear configuration inFIG. 1A, the tool100may be articulated from the linear configuration into various non-linear configurations, as described below with respect toFIGS. 1B-1D. As shown inFIG. 1A, the soft robotic tool100may include a plurality of rigid links110, a plurality of magnetorheological fluid soft joints120, and a plurality of tendons130.

The rigid links110(also referred to herein as “links”) may be disposed in series along the length of the soft robotic tool100. In some embodiments, as shown, the rigid links110may include a first rigid link110a,a second rigid link110b,and a third rigid link110c.In other embodiments, any number of the rigid links110may be used, such as four or more rigid links110, depending on the intended use and desired length of the soft robotic tool100. The rigid links110may be formed as rigid members that do not deform, elastically or plastically, during use of the soft robotic tool100for its intended purpose. In some embodiments, the rigid links110may be formed of a polymeric material, a metallic material, or a ceramic material, although other suitable biocompatible materials may be used for the links110. In some embodiments the polymeric material of the rigid links110may include acrylonitrile butadiene styrene (ABS) or polylactic acid (PIA), although other suitable biocompatible polymeric materials may be used for the links110. The rigid links110may have various regular or irregular shapes. In some embodiments, the rigid links110each may have a cylindrical shape with a circular cross-sectional shape, although other suitable shapes may be used for the links110. The rigid links110each may have a length in the direction of the longitudinal axis of the soft robotic tool100and a width (i.e., a diameter when the links110have a circular cross-sectional shape) in the direction orthogonal to the longitudinal axis of the tool100. In some embodiments, for each of the rigid links110, the length of the link110may be greater than the width of the link110In other embodiments, for each of the rigid links110, the length of the link110may be less than or equal to the width of the link110. In some embodiments, all of the rigid links110may have the same shape and dimensions. In other embodiments, one or more of the rigid links110may have a shape and/or dimension that is different from the shape and/or dimension of one or more of the other rigid links110.

The magnetorheological fluid soft joints120(also referred to herein as “magnetorheological fluidic joints,” “magnetorheological joints,” or simply “joints”) may be disposed in series along the length of the soft robotic tool100and interspersed among the rigid links110. As shown, each magnetorheological fluid soft joint120may be disposed between and connected to a consecutive pair of the rigid links110. In some embodiments, as shown, the magnetorheological fluid soft joints120may include a first magnetorheological fluid soft joint120aand a second magnetorheological fluid soft joint120b.The first magnetorheological fluid soft joint120amay be connected to a distal end of the first rigid link110aand a proximal end of the second rigid link110b.The second magnetorheological fluid soft joint120bmay be connected to a distal end of the second rigid link110band a proximal end of the third rigid link110c.In other embodiments, any number of the magnetorheological fluid soft joints120may be used, such as three or more magnetorheological fluid soft joints120, depending on the intended use and desired length of the soft robotic tool100.

As shown, each magnetorheological fluid soft joint120may include a capsule122containing a magnetorheological fluid124therein, and an inductive coil126disposed around the capsule122. The capsule122may be formed as a flexible container that allows the magnetorheological fluid soft joint120to bend in a bending plane when the joint120is in an unlocked or off state, as described below. In some embodiments, the capsule122may be formed of a polymeric material, although other suitable biocompatible materials may be used for the capsule122. In some embodiments the polymeric material of the capsule122may include silicone, although other suitable biocompatible polymeric materials may be used for the capsule122. The capsules122may have various regular or irregular shapes when the capsule122is in a natural state (i.e., absent external forces acting on the capsule122), although the capsule122may be elastically deformed to various other shapes during use of the soft robotic tool100. In some embodiments, the capsules122each may have a cylindrical shape with a circular cross-sectional shape, although other suitable shapes may be used for the capsules122. The capsules122. each may have a length in the direction of the longitudinal axis of the soft robotic tool100and a width (i.e., a diameter when the capsules122have a circular cross-sectional shape) in the direction orthogonal to the longitudinal axis of the tool100. In some embodiments, for each of the capsules122, the length of the capsule122may be greater than the width of the capsule122. In other embodiments, for each of the capsules122, the length of the capsule122may be less than or equal to the width of the capsule122. In some embodiments, all of the capsules122may have the same shape and dimensions. In other embodiments, one or more of the capsules122may have a shape and/or dimension that is different from the shape and/or dimension of one or more of the other capsules122. In some embodiments, the length of the capsules122may be greater than the length of the rigid links110. In other embodiments, the length of the capsules122may be less than or equal to the length of the rigid links110.

For each magnetorheological fluid soft joint120, the magnetorheological fluid124may include a dispersion of magnetic particles in a non-conductive, non-magnetic carrier fluid. In some embodiments, the magnetic particles may include iron particles, although other suitable magnetic particles may be used for the magnetorheological fluid124. In some embodiments, the carrier fluid may include silicone oil or mineral oil, although other suitable carrier fluids may be used for the magnetorheological fluid124. The magnetorheological fluid124may be configured to transition between an on or magnetized state and an off or un-magnetized state, based on the application of a magnetic field or absence of a magnetic field. When in the off state, the magnetorheological fluid124may exhibit similar fluid behavior to the carrier fluid, which may be generally similar in viscosity to the carrier fluid and Newtonian or slightly shear thinning. When in the on state, the magnetic particles in the magnetorheological fluid124may align with the magnetic field and form chains, with such alignment restricting bulk fluid flow and typically changing the fluid rheological properties to that of a Bingham plastic. In this manner, the magnetorheological fluid124may show a critical yield stress rather than a continuous relationship between stress and strain. For the magnetorheological fluid124, the magnetized viscosity below the yield stress may be significantly higher than that of the non-magnetized fluid. Above the yield stress, the viscosity of the magnetorheological fluid124may be significantly lower and may be expected to be Newtonian or shear thinning. The magnetorheological fluid124may be optimized to have a low non-magnetized viscosity and a high yield stress by adjusting the formulation of the magnetorheological fluid124and/or varying the magnetic field applied during use of the soft robotic tool100. Variables in determining the formulation of the magnetorheological fluid124include the chemistry and viscosity of the carrier fluid, the chemistry, shape, size, and concentration of the magnetic particles, and the addition of additives, if any. In some embodiments, the magnetorheological fluid124may include one or more surfactants, for example, for mitigating potential settling of the magnetic particles. In some embodiments, the one or more surfactants may include an alkanethiol or a mercaptosilane.

For each magnetorheological fluid soft joint120, the inductive coil126may be disposed around the capsule122. The inductive coil126may include a wire formed of a conductive, metallic material. In some embodiments, the inductive coil126may be encapsulated in a thin layer of biocompatible polymer for inhibiting any negative interactions with biological fluids and resisting corrosion. As shown, the inductive coil126may be wound around the capsule122. Although the inductive coil126illustrated inFIG. 1Aincludes three turns, the inductive coil126may include any number of turns as needed to provide a desired strength of the magnetic field without substantially altering the stiffness of the capsule122.

The tendons130(also referred to herein as “driving tendons” or “wires”) may extend along the length of the soft robotic tool100. In some embodiments, as shown, the tendons130may include a first tendon130aand a second tendon130beach extending along the length of soft robotic tool100. In some embodiments, the first tendon130aand the second tendon130bmay extend parallel to one another along at least a portion of the length of the soft robotic tool100. For example, the first tendon130aand the second tendon130bmay extend parallel to one another along at least the distalmost magnetorheological fluid soft joint120. In some embodiments, the first tendon130aand the second tendon130bmay extend along opposite sides of the soft robotic tool100. For example, the first tendon130aand the second tendon130bmay be circumferentially spaced apart from one another by 180 degrees with respect to the longitudinal axis of the tool100. Alternatively, the first tendon130aand the second tendon130bmay be spaced apart from one another by a circumferential offset other than 180 degrees. In some embodiments, more than two tendons130may be used. For example, three, four, five, six, seven, eight, or more tendons130may be used, with the tendons130being equally or unequally spaced apart from one another in a circumferential array with respect to the longitudinal axis of the tool100. In some embodiments, the number of tendons130used may depend on the overall diameter of the tool100. As shown, each tendon130may be attached to each of the rigid links110. In some embodiments, each tendon130may be fixedly attached to the distalmost rigid link110and movably attached to the remainder of the rigid links110. For example, according to the embodiment illustrated inFIG. 1A, the first tendon130aand the second tendon130beach may be fixedly attached to the third rigid link110c,and the first tendon130aand the second tendon130beach may be movably attached to each of the first rigid link110aand the second rigid link110b. In some embodiments, the tendons130may be fixedly attached to the distalmost rigid link110by adhesive, fasteners, or other means for mechanically fixing the tendons130to the distalmost rigid link110. In some embodiments, the tendons130may be attached to the remainder of the rigid links110by passing through respective portions of tendon routing pathways defined by the rigid links110. For example, each rigid link110may define a portion of a first tendon routing pathway for the first tendon130a,and each rigid link110may define a portion of a second tendon routing pathway for the second tendon130b.The respective portions of the tendon routing pathways may be formed as apertures, channels, or other suitable features for receiving a portion of the respective tendon130therethrough. Other suitable means and configurations for attaching the tendons130to the rigid links110may be used in other embodiments. As shown, each tendon130may be unattached with respect to the magnetorheological fluid soft joints120. The tendons130may be formed as elongated, flexible members for controlling motion actuation of the soft robotic tool100. In some embodiments, each tendon130may include a single wire or a plurality of wires. In some embodiments, the tendons130may be formed of a polymeric material, although other suitable biocompatible materials may be used for the tendons130.

FIGS. 1B-1Dillustrate an example of how the soil robotic tool100may be articulated during use of the tool100, for example in navigating a complex pathway.FIG. 1Bshows the soft robotic tool100in a first configuration in which the tool100has a linear shape. In the first configuration, the first and second magnetorheological fluid soft joints120a,120bare in an unlocked or off state (i.e., the magnetorheological fluid124is in the off state due to an absence of a magnetic field applied by the inductive coils126of the joints120a,120b), and the first and second tendons130a,130bare in a slack state. As used herein with respect to a tendon, the term “slack state” refers to a state in which the tendon is not being pulled taut. Further, in the first configuration, the longitudinal axes of the rigid links110a,110b,110care coaxial with one another. The first configuration may be used when the soft robotic tool100is advanced along a linear portion of the complex pathway.

As the distal end104of the soft surgical tool100approaches a first non-linear or branched portion of the complex pathway, the tool100may be moved to a second configuration in which the tool100has a non-linear shape, as shown inFIG. 1C. To transition from the first configuration to the second configuration, the second magnetorheological fluid soft joint120bmay be switched from the unlocked state to a locked or on state (i.e., the magnetorheological fluid124is switched from the off state to the on state due to a magnetic field applied by the inductive coil126of the second joint120b), and the second tendon130bmay be pulled proximally, while the first magnetorheological fluid soft joint120ais maintained in the unlocked state and the first tendon130ais maintained in the slack state. As a result, the pulling of the second tendon130bmay cause the first magnetorheological fluid soft joint120ato bend while the second magnetorheological fluid soft joint120bremains locked. In this manner, the bending of the first magnetorheological fluid soft joint120amay cause the longitudinal axes of the first and second rigid links110a,110bto be angled with respect to one another, while the longitudinal axes of the second and third rigid links110b,110cremain coaxial with one another.

As the distal end104of the soft surgical tool100approaches a second non-linear or branched portion of the complex pathway extending in a direction different from the first non-linear or branched portion, the tool100may be moved to a third configuration in which the tool100has a different non-linear shape, as shown inFIG. 1D. To transition from the second configuration to the third configuration, the first magnetorheological fluid soft joint120amay be switched from the unlocked state to the locked state (i.e., the magnetorheological fluid124is switched from the off state to the on state due to a magnetic field applied by the inductive coil126of the first joint120a), the second magnetorheological fluid soft joint120bmay be switched from the locked state to the unlocked state (i.e., the magnetorheological fluid124is switched. from the on state to the off state due to an absence of a magnetic field applied by the inductive coil126of the second joint120b), and the first tendon130amay be pulled proximally, while the second tendon130bis transitioned to the slack state. As a result, the pulling of the first tendon130amay cause the second magnetorheological fluid soft joint120bto bend while the first magnetorheological fluid soft joint120aremains locked. In this manner, the bending of the second magnetorheological fluid soft joint120bmay cause the longitudinal axes of the second and third rigid links110b,110cto be angled with respect to one another, while the existing angle between the longitudinal axes of the first and second rigid links110a,110bis maintained.

It will be appreciated that the configurations of the soft robotic tool100shown inFIGS. 1B-1Dare merely a few examples of how the tool100may be articulated. For example, the degree of angulation between consecutive rigid links110provided by bending of the magnetorheological fluid soft joints120may be varied, as needed, to navigate a complex pathway. Further, although the illustrated example shows the magnetorheological fluid soft joints120bending in a common bending plane, in other embodiments, the joints may bend in different bending planes that are transverse to one another, as described below. Additionally, as the soft robotic tool100is advanced along a complex pathway, the entire tool100may be rotated within the pathway to facilitate navigation in multiple planes. Further, as described above, the soft robotic tool100may include more than two magnetorheological fluid soft joints120to provide additional degrees of freedom for articulating the tool100. Finally, the soft robotic tool100may include more than two tendons130to facilitate articulation of the tool100in additional bending planes.

FIGS. 2A-2Cdepict a soft robotic tool200(also referred to herein as a “robotic surgical tool,” a “robotic tool” or simply a “tool”) in accordance with one or more embodiments of the disclosure. It will be appreciated that the soft robotic tool200generally may be configured in a manner similar to the soft robotic tool100, although certain differences are described herein. The soft robotic tool200is configured for navigating complex pathways. For example, the soft robotic tool200may be used for navigating complex anatomical pathways, such as in MIS applications. The soft robotic tool200may be formed as an elongated structure having a proximal end202and a distal end204disposed opposite one another along a longitudinal axis of the tool200. Although the soft robotic tool200is depicted in a linear configuration inFIG. 2A, the tool200may be articulated from the linear configuration into various non-linear configurations, as described below. As shown inFIG. 2A, the soft robotic tool200may include a plurality of rigid links210, a plurality of magnetorheological fluid soft joints220, and a plurality of tendons230.

The rigid links210(also referred to herein as “links”) may be disposed in series along the length of the soft robotic tool200. In some embodiments, as shown, the rigid links210may include a first rigid link210a,a second rigid link210b,a third rigid link210c,a fourth rigid link210d,a fifth rigid link210e,and a sixth rigid link210f.In other embodiments, any number of the rigid links210may be used, such as seven or more rigid links210, depending on the intended use and desired length of the soft robotic tool200. The rigid links210may be formed as rigid members that do not deform, elastically or plastically, during use of the soft robotic tool200for its intended purpose. In some embodiments, the rigid links210may be formed of a polymeric material, a metallic material, or a ceramic material, although other suitable biocompatible materials may be used for the links210. In some embodiments the polymeric material of the rigid links210may include acrylonitrile butadiene styrene (ABS) or polylactic acid (PLA), although other suitable biocompatible polymeric materials may be used for the links210. The rigid links210may have various regular or irregular shapes. In some embodiments, the rigid links210each may have a cylindrical shape with a circular cross-sectional shape, although other suitable shapes may be used for the links210. The rigid links210each may have a length in the direction of the longitudinal axis of the soft robotic tool200and a width (i.e., a diameter when the links210have a circular cross-sectional shape) in the direction orthogonal to the longitudinal axis of the tool200. In some embodiments, for each of the rigid links210, the length of the link210may be greater than the width of the link210In other embodiments, for each of the rigid links210, the length of the link210may be less than or equal to the width of the link210. In some embodiments, all of the rigid links210may have the same shape and dimensions. In other embodiments, one or more of the rigid links210may have a shape and/or dimension that is different from the shape and/or dimension of one or more of the other rigid links210.

The magnetorheological fluid soft joints220(also referred to herein as “magnetorheological fluidic joints,” “magnetorheological joints,” or simply “joints”) may be disposed in series along the length of the soft robotic tool200and interspersed among the rigid links210. As shown, each magnetorheological fluid soft joint220may be disposed between and connected to a consecutive pair of the rigid links210. In some embodiments, as shown, the magnetorheological fluid soft joints220may include a first magnetorheological fluid soft joint220a,a second magnetorheological fluid soft joint220b,a third magnetorheological fluid soft joint220c,a fourth magnetorheological fluid soft joint220d,and a fifth magnetorheological fluid soft joint220e.The first magnetorheological fluid soft joint220amay be connected to a distal end of the first rigid link210aand a proximal end of the second rigid link210b.The second magnetorheological fluid soft joint220bmay be connected to a distal end of the second rigid link210band a proximal end of the third rigid link210c.The third magnetorheological fluid soft joint220cmay be connected to a distal end of the third rigid link210cand a proximal end of the fourth rigid link210d.The fourth magnetorheological fluid soft joint220dmay be connected to a distal end of the fourth rigid link210dand a proximal end of the fifth rigid link210e.The fifth magnetorheological fluid soft joint220emay be connected to a distal end of the fifth rigid link210eand a proximal end of the sixth rigid link210f.In other embodiments, any number of the magnetorheological fluid soft joints220may be used, such as six or more magnetorheological fluid soft joints220, depending on the intended use and desired length of the soft robotic tool200.

As shown, each magnetorheological fluid soft joint220may include a capsule222containing a magnetorheological fluid224therein. Each magnetorheological fluid soft joint220also may include an inductive coil (not shown inFIGS. 2A-2C) disposed around the capsule222. The capsule222may be formed as a flexible container that allows the magnetorheological fluid soft joint220to bend in a bending plane when the joint220is in an unlocked or off state, as described below. In some embodiments, the capsule222may be formed of a polymeric material, although other suitable biocompatible materials may be used for the capsule222. In some embodiments the polymeric material of the capsule222may include silicone, although other suitable biocompatible polymeric materials may be used for the capsule222. The capsules222may have various regular or irregular shapes when the capsule222is in a natural state (i.e., absent external forces acting on the capsule222), although the capsule222may be elastically deformed to various other shapes during use of the soft robotic tool200. In some embodiments, the capsules222each may have a cylindrical shape with a circular cross-sectional shape, although other suitable shapes may be used for the capsules222. The capsules222each may have a length in the direction of the longitudinal axis of the soft robotic tool200and a width (i.e., a diameter when the capsules222have a circular cross-sectional shape) in the direction orthogonal to the longitudinal axis of the tool200. In some embodiments, for each of the capsules222, the length of the capsule222may be greater than the width of the capsule222. In other embodiments, for each of the capsules222, the length of the capsule222may be less than or equal to the width of the capsule222. In some embodiments, all of the capsules222may have the same shape and dimensions. In other embodiments, one or more of the capsules222may have a shape and/or dimension that is different from the shape and/or dimension of one or more of the other capsules222. In some embodiments, the length of the capsules222may be greater than the length of the rigid links210. In other embodiments, the length of the capsules222may be less than or equal to the length of the rigid links210.

For each magnetorheological fluid soft joint220, the magnetorheological fluid224may include a dispersion of magnetic particles in a non-conductive, non-magnetic carrier fluid. In some embodiments, the magnetic particles may include iron particles, although other suitable magnetic particles may be used for the magnetorheological fluid224. In some embodiments, the carrier fluid may include silicone oil or mineral oil, although other suitable carrier fluids may be used for the magnetorheological fluid224. The magnetorheological fluid224may be configured to transition between an on or magnetized state and an off or un-magnetized state, based on the application of a magnetic field or absence of a magnetic field. When in the off state, the magnetorheological fluid224may exhibit similar fluid behavior to the carrier fluid, which may be generally similar in viscosity to the carrier fluid and Newtonian or slightly shear thinning. When in the on state, the magnetic particles in the magnetorheological fluid224may align with the magnetic field and form chains, with such alignment restricting bulk fluid flow and typically changing the fluid rheological properties to that of a Bingham plastic. In this manner, the magnetorheological fluid224may show a critical yield stress rather than a continuous relationship between stress and strain. For the magnetorheological fluid224, the magnetized viscosity below the yield stress may be significantly higher than that of the non-magnetized fluid. Above the yield stress, the viscosity of the magnetorheological fluid224may be significantly lower and may be expected to be Newtonian or shear thinning. The magnetorheological fluid224may be optimized to have a low non-magnetized viscosity and a high yield stress by adjusting the formulation of the magnetorheological fluid224and/or varying the magnetic field applied during use of the soft robotic tool200. Variables in determining the formulation of the magnetorheological fluid224include the chemistry and viscosity of the carrier fluid, the chemistry, shape, size, and concentration of the magnetic particles, and the addition of additives, if any. In some embodiments, the magnetorheological fluid224may include one or more surfactants, for example, for mitigating potential settling of the magnetic particles. In some embodiments, the one or more surfactants may include an alkanethiol or a mercaptosilane.

For each magnetorheological fluid soft joint220, the inductive coil may be disposed around the capsule222. The inductive coil may include a wire formed of a conductive, metallic material. In some embodiments, the inductive coil may be encapsulated in a thin layer of biocompatible polymer for inhibiting any negative interactions with biological fluids and resisting corrosion. The inductive coil may be configured in a manner similar to the inductive coil126described above and shown inFIG. 1A, with the inductive coil wound around the capsule222. The inductive coil may include any number of turns as needed to provide a desired strength of the magnetic field without substantially altering the stiffness of the capsule222.

The tendons230(also referred to herein as “driving tendons” or “wires”) may extend along the length of the soft robotic tool200. In some embodiments, as shown, the tendons230may include a first tendon230aand a second tendon230beach extending along the length of soft robotic tool200. In some embodiments, the first tendon230aand the second tendon230bmay extend parallel to one another along at least a portion of the length of the soft robotic tool200. For example, the first tendon230aand the second tendon230bmay extend parallel to one another along at least the distalmost magnetorheological fluid soft joint220. In some embodiments, the first tendon230aand the second tendon230bmay extend along opposite sides of the soft robotic tool200. For example, the first tendon230aand the second tendon230bmay be circumferentially spaced apart from one another by 180 degrees with respect to the longitudinal axis of the tool200over at least a portion of the length of the tool200. Alternatively, the first tendon230aand the second tendon230bmay be spaced apart from one another by a circumferential offset other than 180 degrees. In some embodiments, more than two tendons230may be used. For example, three, four, five, six, seven, eight, or more tendons230may be used, with the tendons230being equally or unequally spaced apart from one another in a circumferential array with respect to the longitudinal axis of the tool200over at least a portion of the length of the tool200. In some embodiments, the number of tendons230used may depend on the overall diameter of the tool200. As shown, each tendon230may be attached to each of the rigid links210. In some embodiments, each tendon230may be fixedly attached to the distalmost rigid link210and movably attached to the remainder of the rigid links210. For example, according to the embodiment illustrated inFIGS. 2A-2C, the first tendon230aand the second tendon230beach may be fixedly attached to the sixth rigid link210f,and the first tendon230aand the second tendon230beach may be movably attached to each of the first rigid link210a,the second rigid link210b,the third rigid link210c,the fourth rigid link210d,and the fifth rigid link210e.In some embodiments, the tendons230may be fixedly attached to the distalmost rigid link210by adhesive, fasteners, or other means for mechanically fixing the tendons230to the distalmost rigid link210. In some embodiments, the tendons230may be attached to the remainder of the rigid links210by passing through respective portions of tendon routing pathways defined by the rigid links210. For example, in the illustrated embodiment, each rigid link210may define a portion of a first tendon routing pathway for the first tendon230a,and each rigid link210may define a portion of a second tendon routing pathway for the second tendon230b.The respective portions of the tendon routing pathways may be formed as apertures, channels, or other suitable features for receiving a portion of the respective tendon230therethrough. Other suitable means and configurations for attaching the tendons230to the rigid links210may be used in other embodiments. As shown, each tendon230may be unattached with respect to the magnetorheological fluid soft joints220. The tendons230may be formed as elongated, flexible members for controlling motion actuation of the soft robotic tool200. In some embodiments, each tendon230may include a single wire or a plurality of wires. In some embodiments, the tendons230may be formed of a polymeric material, although other suitable biocompatible materials may be used for the tendons230.

FIGS. 2B and 2Cprovide detailed views showing example portions of the first tendon routing pathway and the second tendon routing pathway defined by the rigid links210.FIG. 2Bshows the second rigid link210band the portions of the first tendon routing pathway and the second tendon routing pathway defined by the second rigid link210b,with the first tendon230aand the second tendon230bextending along the respective portions of the tendon routing pathways. As shown, the portion of the first tendon routing pathway defined by the second rigid link210bmay extend in a linear manner along the length of the second rigid link210b,and the portion of the second tendon routing pathway defined by the second rigid link210bmay extend in a linear manner along the length of the second rigid link210b.In some embodiments, as shown, the portion of the first tendon routing pathway defined by the second rigid link210band the portion of the second tendon routing pathway defined by the second rigid link210beach may extend parallel to the longitudinal axis of the second rigid link210b. In this manner, along the length of the second rigid link210b,the first tendon230aand the second tendon230beach may extend in a linear manner and parallel to the longitudinal axis of the second rigid link210b.

FIG. 2Cshows the third rigid link210cand the portions of the first tendon routing pathway and the second tendon routing pathway defined by the third rigid link210c,with the first tendon230aand the second tendon230bextending along the respective portions of the tendon routing pathways. As shown, the portion of the first tendon routing pathway defined by the third rigid link210cmay extend in a non-linear manner along the length of the third rigid link210c,and the portion of the second tendon routing pathway defined by the third rigid link210cmay extend in a non-linear manner along the length of the third rigid link210c.In some embodiments, as shown, the portion of the first tendon routing pathway defined by the third rigid link210cmay be curved along the length of the third rigid link210csuch that a proximal end of the portion of the first tendon routing pathway is circumferentially offset from a distal end of the portion of the first tendon routing pathway with respect to the longitudinal axis of the third rigid link210c.For example, the proximal end and the distal end of the portion of the first tendon routing pathway defined by the third rigid link210cmay be circumferentially offset from one another by 90 degrees, as shown. Similarly, the portion of the second tendon routing pathway defined by the third rigid link210cmay be curved along the length of the third rigid link210csuch that a proximal end of the portion of the second tendon routing pathway is circumferentially offset from a distal end of the portion of the second tendon routing pathway with respect to the longitudinal axis of the third rigid link210c.For example, the proximal end and the distal end of the portion of the second tendon routing pathway defined by the third rigid link210cmay be circumferentially offset from one another by 90 degrees, as shown.

The configurations of the first tendon routing pathway and the second tendon routing pathway shown inFIGS. 2A-2Cmay facilitate bending of different magnetorheological fluid soft joints220in different bending planes or the same bending plane. According to the illustrated configurations, the tendons230a,230bmay be configured to bend the first magnetorheological fluid soft joint220a,the second magnetorheological fluid soft joint220b,and the fifth magnetorheological fluid soft joint220ein a first bending plane, and the tendons230a,230bmay be configured to bend the third magnetorheological fluid soft joint220cand the fourth magnetorheological fluid soft joint220din a second bending plane that is transverse to the first bending plane. For example, the second bending plane may be orthogonal to the first bending plane, although other transverse orientations may be used. In this manner, the tendon routing pathways may allow the tendons230to bend the magnetorheological fluid soft joints220in multiple bending planes to achieve various articulated configurations of the soft robotic tool200. It will be appreciated that the configurations of tendon routing pathways of the soft robotic tool200shown inFIGS. 2A-2Care merely one example, and that other configurations may be used for bending the magnetorheological fluid soft joints220in two, three, or more different bending plans.

During use, the soft robotic tool200may be articulated in various configurations, in a manner similar to the soft robotic tool100described above with reference toFIGS. 1B-1D, for navigating a complex pathway. In particular, the magnetorheological fluid soft joints220may be sequentially switched from a locked or on state (i.e., in which the magnetorheological fluid224is in the on state due to magnetic fields applied by the inductive coils of the joints220) to an unlocked or off state (i.e., in which the magnetorheological fluid224is in the off state due to an absence of a magnetic field applied by the inductive coils of the joints220), and one of the tendons230may be pulled while the other tendon230is in a slack state to bend the unlocked magnetorheological fluid soft joint220. In this manner, the soft robotic tool200may be transitioned from one configuration to another to facilitate navigation of the complex pathway.

FIG. 3depicts a robotic system300(also referred to herein as a “soft robotic system,” a “robot,” or simply a “system”) in accordance with one or more embodiments of the disclosure. The robotic system300may be configured for navigating complex pathways and performing a procedure. For example, the robotic system300may be configured for navigating anatomical complex pathways and performing a surgical procedure, such as an MIS procedure. As shown inFIG. 3, the robotic system300may include the soft robotic tool200described above and an actuation module310configured to guide and articulate the soft robotic tool200for navigating a complex pathway and performing a procedure.

As shown, the actuation module310may include one or more motor(s)312, one or more actuator(s)314, one or more current generator(s)316, and one or more control unit(s)320. The motor(s)312may be configured to advance and retract the soft robotic tool200relative to the actuation module310. In this manner, during use of the robotic system300, the motor(s)312may be used to advance the soft robotic tool200along a complex pathway, such as a complex anatomical pathway within the body of a patient, for carrying out a procedure, and to retract the tool200after completion of the procedure. In some embodiments, a plurality of motors312may be used, for example, with one motor312for advancing the soft robotic tool200and another motor312for retracting the tool200. In other embodiments, a single motor312may be used for advancing and retracting the soft robotic tool200.

The actuator(s)314may be configured to drive the tendons230of the soft robotic tool200. In this manner, during use of the robotic system300, the actuator(s)314may be used to pull one of the tendons230while allowing a remainder of the tendons230to assume the slack state, thereby causing the soft robotic tool200to articulate to assume various non-linear configurations as needed to navigate a complex pathway. In some embodiments, a plurality of actuators314may be used, for example, with the number of actuators314corresponding to the number of tendons230. In this manner, each actuator314may be mechanically coupled to and configured to drive only one of the tendons230. In other embodiments, a single actuator314may be used in conjunction with a mechanism for switching which tendon230is pulled at a particular time during a procedure.

The current generator(s)316may be configured to generate current for magnetizing the inductive coils of the magnetorheological fluid soft joints220of the soft robotic tool200. In this manner, during use of the robotic system300, the current generator(s)316may be used to selectively direct current to the inductive coils to switch the respective magnetorheological fluid soft joints220between the locked state and the unlocked state for allowing articulation of the soft robotic tool200about the unlocked magnetorheological fluid soft joint220. In some embodiments, a plurality of current generators316may be used, for example, with the number of current generators316corresponding to the number of magnetorheological fluid soft joints220. In this manner, each current generator316may be in electrical communication with and configured to magnetize the inductive coil of only one of the magnetorheological fluid soft joints220. In other embodiments, a single current generator316may be used in conjunction with a mechanism for distributing current to the desired inductive coils of the magnetorheological fluid soft joints220at a particular time during a procedure.

The control unit(s)320may be configured to control operation of the motor(s)312, the actuator(s)314, and the current generator(s)316to facilitate desired movement and articulation of the soft robotic tool200. In this manner, during use of the robotic system300, the control unit(s)320may be used to selectively activate the motor(s)312for advancing and retracting the soft robotic tool200, to selectively actuate the actuator(s)314for driving the tendons230of the tool200, and to selectively cause the current generator(s)316to magnetize the inductive coils of the magnetorheological fluid soft joints220of the tool200. In some embodiments, the control unit320may include a plurality of controllers for controlling operation of the motor(s)312, the actuator(s)314, and the current generator(s)316. As shown, the control unit320may include one or more motor controller(s)322, one or more actuator controller(s)324, and one or more current controller(s)326. The motor controller(s)322may be configured to control activation of the motor(s)312for advancing and retracting the soft robotic tool200. The actuator controller(s)324may be configured to control actuation of the actuator(s)314for driving the tendons230of the soft robotic tool200. In some embodiments, the actuator controller(s)324may be configured to cause only one of the tendons230to be pulled while a remainder of the tendons230are maintained in the slack state. The current controller(s)326may be configured to control the current generated by the current generator(s)316for magnetizing the inductive coils of the magnetorheological fluid soft joints220of the soft robotic tool200. In this manner, the current controller(s)326may control a strength of a magnetic field generated by the respective inductive coils of the magnetorheological fluid soft joints220. In some embodiments, the current controller(s)326may be configured to cause only one of the magnetorheological fluid soft joints220to assume the off state while a remainder of the joints220assume the on state. In some embodiments, the motor controller(s)322, the actuator controller(s324, and the current controller(s)326may be provided as separate, discrete controllers. In other embodiments, the motor controller(s)322, the actuator controller(s)324, and the current controller(s)326may be provided as portions or modules of a single controller. It will be appreciated that various configurations of the control unit320may be used to achieve the functions described above.