Self-Propelled Tubular Apparatus

This application claims the benefit of priority to U.S. Provisional Application No. 63/641,141, filed May 1, 2024, and to U.S. Provisional Application No. 63/743,462, filed Jan. 9, 2025, each of which applications is incorporated herein by reference in its entirety.

This invention was made with government support under 1850168 and 2047330 awarded by the National Science Foundation; and DE-AR0001854 awarded by the Department of Energy. The government has certain rights in the invention.

This disclosure relates to a self-propelled tubular apparatus, systems, and methods for moving a peristaltic actuator system through a medium.

Undergrounding is the process by which electrical power or telecommunications cables are run underground within protective conduits rather than as overhead cables. Running cables overhead is currently significantly less expensive and faster than undergrounding but is much more susceptible to being damaged due to weather or other events. Current methods for undergrounding are labor-intensive, slow, expensive, and unsafe and need to be improved or replaced. For example, the two most common methods for undergrounding are open trenching and horizontal directional drilling (HDD). Open trenching involves a complete excavation for a trench of the length and depth needed to install new conduit. This trenching process is especially labor-intensive in urban environments due to the extensive planning needed to ensure other existing underground systems (such as water, sewer, communications, etc.) are not damaged during excavation and installation of new conduit. Sometimes accurate underground maps of old buried infrastructures don't exist and even with careful planning and accurate maps it is not uncommon for existing infrastructures to be damaged during the trenching process which adds additional labor time and costs for repairs. HDD can install new conduit by drilling new tunnels underground without major disruption to surfaces. HDD utilizes a series of connected metal drill pipes with a slightly steerable drill bit at the end that is all pushed by a directional drill machine on the surface. Drilling fluid is pumped through the drill pipes to the drill bit to hydraulically power the drill bit, remove cuttings from the soil that are pushed back to the surface, and to provide structural support for the new borehole. While HDD is a slightly steerable process and is generally suitable for drilling new holes in well documented and mapped existing underground infrastructures, the HDD drill bit can unintentionally hit an existing piece of infrastructure and cause damage.

This description relates to self-propelled tubular structures, such as peristaltic actuating apparatuses, systems and methods.

A described example relates to an apparatus that includes a plurality of axially spaced apart rings defining a radially inner surface that defines a hollow central lumen extending longitudinally through the apparatus. Respective actuators are coupled to at least some of the rings outside of the central lumen. An elongated expandable tubular structure extends over the rings and the actuators, in which the actuators are adapted to change a span and/or diameter of the expandable tubular structure at respective locations along the length of the expandable tubular structure, whereby peristaltic movement of the apparatus is provided.

Another example relates to a peristaltic actuating system that can include an elongated body that includes an arrangement of substantially tubular body segments, in which each of the body segments has a radially inner sidewall portion that is elastically deformable in an axial direction and defines a lumen that is coaxial with lumens of the other body segments to define a central body lumen extending longitudinally through the elongated body. The central body lumen can be configured to carry an elongated tubular apparatus therein and/or can itself define a tubular body structure that can carry one or more structures therein. Each of the body segments includes a flexible outer sidewall portion configured to expand radially and provide a radially outward force responsive to axial contraction of the respective body segment and to contract radially responsive to axial elongation of the respective body segment.

Another example relates to a locomotion system that includes an elongated body having a central body lumen extending longitudinally through the elongated body, the central body lumen defines or is configured to carry an elongated tubular apparatus therein. The system includes a first body segment at a first location along the elongated body and a second body segment at a second location along the elongated body, which is spaced axially apart from the first body segment. Each of the first and second body segments is configured to independently actuate radially and/or axially with respect to the elongated body and the other body segment to provide peristaltic motion of the body segments and corresponding longitudinal motion of the elongated body and respective segments through a surrounding media.

This disclosure relates to apparatuses, systems, and methods for moving through media based on peristaltic locomotion.

As an example, a self-propelled tubular apparatus (e.g., peristaltic actuating apparatus or a peristaltic sleeve robot) can include an elongated body that extends between distal and proximal ends. The body of the apparatus can include an elongated expandable outer structure (e.g., a water resistant, pliant fabric) that surrounds a hollow interior space defining a central lumen that extends through the body and adapted to support an elongated tubular structure therein. In some examples, a conduit (or other flexible tubular structure) can extend through the lumen and defines a radially inner surface adapted to support one or more elongated tubular structures therein. The apparatus also includes one or more actuators that are configured to change a span and/or or diameter of the expandable outer structure at respective locations along the length of the body to provide for peristaltic movement of the apparatus and any one or more structures (e.g., conduit and/or cables) that may be disposed with the interior space thereof the apparatus.

As another example, a peristaltic actuating apparatus (e.g., a peristaltic or worm-like robot) includes a plurality of axially spaced apart rings. The rings can be formed of rigid materials and adjacent pairs of rings can be coupled together by flexible interconnects (e.g., flexible arches) to define an inner sidewall of the apparatus. For example, the radially inner sidewall surfaces of the rings are arranged and configured to support a length of an elongated tubular structure (e.g., a flexible conduit, pipe, or duct) within the tubular sidewall thereof. For example, the rings can be configured to slide along and/or attach to an outer sidewall surface of an elongated tubular structure (e.g., a flexible conduit), which is to be transported by the apparatus through a medium. The apparatus also includes respective actuators coupled to at least some of the rings. An elongated expandable tubular outer structure (e.g., a skin or covering of a flexible fabric or other material) can extend over a number of the rings, flexible interconnects, and actuators to define a radially outer sidewall of the apparatus. A volume between the outer sidewall (defined by the tubular covering) and the inner sidewall (defined by the rings and interconnects) can define a fluid chamber (e.g., a sealed chamber) that is filled with fluid. The actuators can be configured to change a span (axial length) and/or diameter of the expandable tubular outer structure at respective locations along the length of the apparatus to implement peristaltic movement thereof.

In some examples, the elongated body includes an arrangement of substantially tubular body segments. The elongated body thus can define a multi-segmented worm-like robot, in which respective body segments are configured to actuate in a pattern to implement peristaltic locomotion of the elongated body. Each of the body segments has a radially inner sidewall portion that defines a lumen thereof and is deformable in an axial direction. The lumens of the body segments can be coaxial with respect to each other to define a central body lumen extending longitudinally through the elongated body. In one example, the central body lumen is hollow and configured to carry (e.g., transport) an elongated flexible tubular apparatus (e.g., a conduit) therein through a medium (e.g., underground). In another example, the central body lumen defines a flexible tubular sidewall that contains one or more cables (e.g., electrically conductive wires, optical fibers or the like) that are to be transported through the medium (e.g., underground) by the apparatus.

As a further example, each of the body segments includes a radially flexible outer covering (e.g., an outer membrane). For example, each of the body segments can include a number of rings spaced axially apart by flexible interconnects to define an inner sidewall thereof and the flexible outer covering over the rings and interconnects to define an outer sidewall of the respective body segment. The flexible outer covering can be configured to expand radially and provide a radially outward force responsive to axial contraction of the body segment and to contract radially responsive to axial elongation of the body segment. The radially outward forces can sufficiently radially expand into a surrounding media (e.g., soil) while supporting the forces necessary for advancement of a distal end (e.g., drilling head). One or more actuators can be coupled at least some of the body segments and configured to cause the axial contraction and/or the axial elongation of the at least one of the body segments responsive to a control signal from a controller, which can be implemented on the tubular body or remotely located and coupled to the tubular body through a communications link (e.g., physical or wireless link). As described herein, actuators can be implemented as fluidic (e.g., pneumatic or hydraulic) powered peristaltic actuators. Also, or alternatively, one or more actuators can be implemented as electromotor powered peristaltic actuators (e.g., rotary motors, linear motors, or the like). Other types of actuators can be used in other examples.

In some examples herein, a distal (e.g., front) end of the elongated body can include a tool, such as a drill head tool or other mechanism configured to drill, dig, bore, and/or pierce through the medium (e.g., soil). The distal end can also include an arrangement of sensors (e.g., contact sensors, force sensors, spatial positioning sensors, cameras, and the like) for providing feedback for controlling operation of the apparatus. Removed soil cuttings and other debris can be conveyed from the distal end tool (e.g., drill head) and be deposited into the inside of the tubular body, such as within the main central lumen or a separate lumen (e.g., within or alongside the central lumen) adapted for transporting debris through the tubular body. An industrial vacuum can be located above ground (e.g., in a truck, trailer or other container) and be fluidly coupled to a proximal end of the tubular body conduit. The industrial vacuum can be configured to vacuum out the soil cuttings and debris from within tubular body.

is a schematic diagramillustrating an example use scenario that can be implemented by a peristaltic actuating apparatus(also referred to herein as a peristaltic sleeve), such as according to any of the example embodiments described herein. The apparatusincludes an elongated tubular bodyextending longitudinally between spaced apart proximal and distal endsandthat is adapted to carry a structure within a hollow interior space thereof. In examples described herein, the hollow interior space can define one or more lumensthat extend from the distal endlongitudinally through the tubular body. As shown in, an elongated tubular structure (e.g., a flexible conduit)can be positioned within the lumen, which can be transported within the apparatusduring burrowing through a medium (e.g., earth, such as soil, rocks, water, or the like). Also, or alternatively, one or more elongated tubular structures can be inserted into and through the lumenafter the apparatushas reached its desired destination.

The apparatusincludes a plurality of axially spaced apart ringsarranged along a length of the tubular body. An inner surface of the rings can be configured according to configuration of the conduitand be adapted to support a length of the conduittherein. The rings(at least some of the rings) can be configured to slide along and/or attach to an outer surface of the conduit. One or more actuatorscan be coupled to at least some of the rings. As described herein, various types and configurations of actuators can be implemented.

The apparatusfurther can include an elongated expandable flexible coveringover the ringsand the actuators. As described herein, the coveringcan include a flexible tubular membrane or shell formed of one or more layers of flexible material (e.g., fabrics, polymers, etc.). The flexible coveringcan expand and contract radially responsive to changing an axial distance between two more of the rings. The mechanism to change the axial distance between rings depends on the type and arrangement of actuators implemented in the apparatus. More than one type of actuators can be implemented in the apparatus for providing peristaltic movement of the apparatus. In the example of, one or more flexible connecting elementscan be coupled between adjacent ringsand to one or more actuators. For example, the actuatoris configured to change the length of the connecting elementsand thereby cause a corresponding change in an axial distance between two more of the rings. In response to axial contraction (e.g., shortening) of the connecting element(s)the axial distance between ringsdecreases and the flexible coveringcan expand radially outwardly, such as shown in regionof the elongated tubular body. Such radial expansion in the flexible coveringcan thus provide a radially outward force into surrounding ground, which can fix the regionwith respect to the surrounding medium. While the regionis fixed, one or more other regions, which can be distal or proximal or distal to the fixed region, can axially elongate (e.g., by increasing the distance between two or more adjacent rings) to provide for peristaltic movement of the apparatusthrough the medium. Also, responsive to the axial elongation between adjacent rings in the other region, which can be actively controlled or passively allowed, the flexible coveringin such other region(s) contracts radially facilitating the peristaltic movement of the apparatus. In the example of, the apparatus includes drill toolat the distal end. The radially outward forces applied to the surrounding medium by the expanded regioncan be sufficient to support the region to enable the drill tool to advance the distal regionof the elongated tubular bodyfurther into the medium. Also, or alternatively, the radially outward forces applied to the surrounding medium by the expanded regioncan be sufficient to enable the drill toolto implement turning of the distal end in a desired direction.

As a further example,depicts a diagramof a peristaltic waveform that can be implemented by a peristaltic apparatus(e.g., a worm-like robot carrying a conduit) described herein. As shown in, the apparatusincludes a plurality of segmentsA,B,C,D,E,F,G, andH extending between ends thereofand. A conduitthat can be carried by the apparatusis shown with dashed lines. A boundary of the surrounding medium is shown at. In the diagram, hollow circles represent features coupled to the conduitand asterisks represent features coupled to the robotic segments (e.g., actuators) of the apparatus. The left side of the segmentH is shown rigidly attached to the conduitto define a first anchoring point. Given the first anchoring point any other suitable locations for anchoring onto the conduit are shown by their asterisk not moving within their corresponding hollow circle throughout the entire peristaltic motion shown in. For example, the right side of the segmentD and the right side of the eighth segmentG are shown as suitable anchoring locations. Various mechanisms can be utilized to anchor part of a segment to the conduit, which can remain fixed during peristaltic motion or can attach and release through the motion process. Also, or alternatively, some segments of a given apparatus (e.g., one or more segments near a drill head or other distal tool) can be free to slide along the length of the conduit without including any anchoring. As shown in, each of the segmentsA,B,C,D,E,F,G, andH can be configured to implement radial expansion and axial elongation based on a peristaltic waveform applied to the respective segments by controlling respective actuators of the apparatus. In some examples, segments can be controlled together in certain groups, which groups can be configured so that the peristaltic waveform will be in the same position for each worm segment within a given group (e.g., all actuators within a given group will actuate in unison). In an example, segmentsA andE can define a first group, segmentsB andF can define a second group, segmentsC andG can define a third group, and segmentsD andH can define a fourth group. Other numbers and arrangements of groups can be used in other examples.

depict an example embodiment of an electromotor peristaltic actuating apparatus, in which the same reference numbers are used to refer to respective parts and features throughout the various views. The peristaltic actuating apparatusis an example of the apparatus ofand can be controlled to implement a peristaltic waveform, such as described herein (e.g.,). Accordingly, reference can be made to certain aspects ofas well as other figures herein in the description of.

is a perspective view andis a side view of the example peristaltic actuating apparatus. The apparatusincludes an elongated bodyextending longitudinally between spaced apart endsand. The apparatusincludes a plurality of body segmentsarranged along a length of the body. While eight body segmentsas shown in this example, there can be any number of body segmentsdepending on the axial length of respective segments and desired length of the apparatus. The bodyof the apparatuscan have a hollow interior, which is configured to hold and/or carry an elongated flexible tubular structure (e.g., a flexible conduit). In other examples, the hollow interior (e.g., the inner periphery) of the apparatuscan itself define an elongated tubular structure into which cables can be fed and/or pulled through.

Each of the body segmentsat respective endsandcan define end segments that can be coupled to an outer surface of flexible tubular structure (conduit)by anchor couplingsandat respective end locations. The apparatuscan also include one or more segment-to-segment anchor couplingsat intermediate locations along the bodyof the apparatus. Each segment-to-segment anchor couplingis configured to attach the bodyto the conduit.

is an exploded view showing an example of an end anchor coupling. The anchor coupling can include multiple portions (e.g., separable halves)andthat are bolted together at the respective flangesand. The anchor couplings,,can be configured to clamp down on the conduit tightly without causing non-superficial damage. A segment connecting bar further connects the anchor to the body segment. There can be a second segment connecting bar (not shown) underneath the conduit and behind the end anchor. Segment connecting bars(see, e.g.,) can also be used for connecting two adjacent segments together when there is not an anchor in between such segments. Anchor shrouds further can slide over and interlock with the end anchor couplings,to prevent soil debris from entering the interior of the body.

are views of example end anchor and actuator segments, in whichis a cross-sectional view of. Similarly,are views of the example end anchor and actuator sections of, respectively, rotated 90 degrees about a central axis, and in whichis a cross-sectional view of.

As shown in the cross-sectional views of, a central lumenextends longitudinally through the plurality of body segmentsof the elongated body. The lumendefines a hollow tubular volume that can hold the conduit, as described herein. Additionally, each of the body segmentscan include a plurality of substantially rigid annular rings. The ringscan be axially spaced apart along a length of a respective body segmentbetween a proximal end ring and a distal end ring of the respective segment. The ringscan be arranged orthogonal with respect to a central axisthat extends through the central lumenthe respective segment. A radially inner periphery of each ringcan be configured to slide along an outer surface of the conduit, such as during axial elongation or axial contraction of the respective segment. In some examples, radially inner surfaces of the rings and connecting elements define a portion of the central lumenassociated with the respective body segment or one or more layers of material can be coupled to the radially inner surfaces of the rings to define the lumen.

Each of the body segmentscan include an arrangement of flexible connecting elements. The flexible connecting elementscan be configured to enable relative axial movement between the adjacent pair of rings(e.g., to increase or decrease the axial distance between opposing edges of adjacent rings). For example, the flexible connecting elementscan be in the form of respective curved arches (or other shapes of interconnects) coupled between adjacent pairs of the rings, such as at radially outer ends thereof. In an example, the flexible connecting elementsfor a respective body segmentcan be in the form of a cylindrical sheet of flexible material that is revolved about central lumenand coupled to the radially outer ends of the rings. The ringsand the flexible connecting elementscan define an inner sidewall for the respective body segment.

Each of the body segmentsfurther can include an elongated expandable tubular outer structure, which can define a radially outer sidewall of the apparatus. The tubular outer structurethus can be revolved around the central axissuch as spaced radially outwardly from and substantially coextensive with the inner sidewall defined by the ringsand elements. For example, the tubular outer structurethus can include one or more layers of a flexible skin or covering (e.g., fabric or other flexible material). In an example, proximal and distal ends of the tubular outer structurecan be coupled to respective proximal and distal ends of the inner flexible connecting elements, such as by respective end caps or other mounting structures. Such mounting structures can be configured to mount the tubular outer structurearound the inner sidewall to define a volume between the outer sidewall (defined by the tubular covering) and the inner sidewall (defined by the rings and elements). As described herein, the volume can define a fluid chamber(e.g., a sealed chamber) that is filled with fluid. In other examples, more than one fluidic chamber can be provided between the tubular outer structureand the inner sidewall structure. The sealed fluidic chamber(s) can be adapted to emulate a constant volume constraint similar to that found on biological earthworm segments. In some examples, each body segment can include a valve coupled with the volume within the chamber, which can be used to set a pressure of the fluid within the volume depending on application requirements.

The apparatusfurther can include an arrangement of elongated protective sleeves configured to carry electrical wires, which can provide power and control signals for controlling respective electromotors, as described herein. The protective sleeves can extend through the central lumen(e.g., along the inner periphery thereof). Also, or alternatively, one or more protective sleeves can define one or more other lumens (e.g. tubular members) that extend along the sidewall of the bodyradially outwardly from the sidewall of the central lumen, which can be axially aligned and connected with respective sleeves in other body segments.

is an exploded view of an example segment-to-segment anchor coupling. The segment-to-segment couplingcan be composed of two separable halves that can be fastened together at the shown flanges (e.g., by bolts or other fasteners). The segment-to-segment couplingcan also be configured to clamp down on the conduittightly without causing non-superficial damage. For example, anchor segment connecting barscan be used to connect the couplingto each of the adjacent body segments. Anchor shrouds can slide over and interlock with the end anchor to prevent soil and other debris from entering the lumen of the body.

are views of another example segment-to-segment anchor coupling, in whichis a cross-sectional view of.are views of the example segment-to-segment anchor section of, respectively, rotated about 90 degrees about the central axis, and in whichis a cross-sectional view of.

demonstrate an example of actuating hardware (also referred to herein as an actuator)for a respective body segment. As shown in the examples of, the actuatorfor a respective body segmentcan include a motor section(e.g., one or more electric servomotors) located at one end of the body segment. The electric actuators in this example can be referred to as electromotor peristaltic actuators (EMPA). As described herein, one or more types of actuators (e.g., rotary actuators or linear actuators) can be utilized to implement the actuating hardwarefor the body segment. Associated non-motor hardware sectioncan be located at the opposite end of the body segment. Advantageously, the central lumennot only extends through a central expandable and/or retractable region of the body segmentbut completely through the segment, including through the motor sectionand non-motor hardware sectionat the ends of the segment.

is a perspective view of a body segmentandare cross-sectional views of the example body segment of. For completeness, the example ofalso shows some hidden features. As shown in the cross-sectional views of, the actuatorin combination with connecting elements and pulleys running from chambers of the motor sectionto the mounting flanges can be configured to perform axial contraction of the body segment. As shown in the example of, a path of a connecting element(e.g., braided polyethylene wire or cable) is shown as extending between the motor sectionand the non-motor hardware section, such as through the volume (e.g., between the inner and sidewalls of the segment). The connecting element can traverse through the volume one or more times. For example, one end (e.g., a starting end) of the connecting elementcan connect to a pulley connected to a drive shaft of the motor. An opposite end of the connecting elementcan be terminated by a knot (e.g., or other coupling or fastener) in the non-motor hardware section. One or more other motors (not shown) can implement a similar respective path for its connecting element through the body segment. Those skilled in the art will appreciate various arrangements of one or more connecting elements that can traverse through the body segment, partially and wholly, for changing the length of the body segment. For example, while the arrangement ofis implemented to provide for axial contraction of the body segment, other configurations and arrangements could be implemented to provide for axial elongation or a combination of contraction and elongation.

are perspective views of the body segment showing the motor sectionin an exploded condition. As shown in, the motor section includes two electromotorsand. Other numbers of motors can be used in other examples. The electromotorsandcan be assembled within a ring-like frame prior to being attached to the body segmentusing an arrangement of fasteners (e.g., bolts). In some examples, a valve(e.g., a Schrader air valve or other type of valve) can be communicatively coupled with sealed fluidic chamberto allow gas or other fluid to be removed or added to the volume within the chamber. By way of example, gas or other fluid can be added to further increase the starting pressure of the sealed fluidic chamber, increasing the stiffness of the structure, allowing higher radial forces to be achieved during actuation at the cost of requiring higher actuating forces from the motors. Also, or alternatively, during fabrication, by pumping into the valveany gas leaks in the structure can be identified and repaired (e.g., using a simple soapy water or other leak detection method). An air valve access cover can be provided to help to prevent soil debris from entering or otherwise interfering with the valve. Various fluidic media can be used in the sealed fluidic chamber, such as air, water, oils, gels, etc., and as the incompatibility of the fluidic media increases, greater radial forces are able to be transferred to the surrounding medium (e.g., tunnel walls).

are perspective views of an example body segmentshowing the non-motor side of the segment with the non-motor sectionin an exploded condition. The non-motor sectioncan be in the form of a ring-like frame that can be assembled prior to being attached to the body segment using an arrangement of fasteners (e.g., bolts). In the example of, two of the ring-like parts of the frame can include internal channels which can guide the connecting element(s)that are actuated by the motorsand(e.g., one motor for each side).

shows a partial sectional view of a respective body segmentof the example peristaltic actuator apparatusin a plurality of different deformation conditions, shown at,, and. In the examples of, the body segmentis demonstrated as including the rings, connecting element, and the tubular outer structure, which define the fluidic chamber. The body segment is also shown with a flexible conduitextending through the lumenthereof. Also, in the example of, the body segmentis within an inner periphery of a tunnel (e.g., borehole), such as can result from drilling through a medium (e.g., ground) with the peristaltic actuator apparatusor otherwise forming the tunnel and moving the peristaltic actuator apparatus therethrough by peristaltic motion.

By way of example, the body segmentof the example peristaltic actuator apparatusis shown in a resting or initial position at. The body segmentof the example peristaltic actuator apparatus, is shown at, as the segment begins undergoing axial contraction and radial expansion responsive to an axial compressive force from the electromotors being applied to the sealed fluidic chamber. For example, axial contraction can be implemented based on activation of one or more electromotorsandto shorten the length of connecting elementsthrough the body segment. As shown at, the body segmentof the actuator apparatusis undergoing further axial contraction during actuation, which causes the flexible tubular outer structureto contact the tunnel wallsurrounding the apparatus. As the sealed chamberis driven to have a shorter axial length by the electromotorsand, the sealed chamber inherently seeks to increase in diameter or expand radially, which occurs as the outer sidewallof the sealed chamber(e.g., formed of a flexible skin or membrane) contacts the tunnel wall, as shown at. Because the sealed chamberis sealed, the flexible tubular outer structuremakes conforming contact with the tunnel wall. Furthermore, significant radial force acting on the tunnel wall can be transmitted via the sealed fluidic chamber due to the forces from axial contraction. Having large tunnel wall radial forces can be important in undergrounding applications because significant radial grip would be needed to support the drill bit thrust and torques required. Current simulations indicate that the use of simply atmospheric pressure air in the sealed chamber would be more than sufficient to provide these desired radial forces. As the electromotors release tension in the cables, the inherent stiffness of the design will encourage it to return to its original shape (shown at), with aid from additional spring-like elements, which can be coupled between some or all the rings.

depict an example embodiment of a fluidic powered peristaltic actuating apparatus, in which the same reference numbers are used to refer to respective parts and features throughout the various views. The peristaltic actuating apparatusprovides an example of the apparatusofand can be controlled to implement a peristaltic waveform to move the apparatus through a medium, such as described herein (see, e.g.,). Accordingly, reference can be made to certain aspects ofas well as other figures herein in the description of.

is a perspective view andis a side view of the example peristaltic actuating apparatus. The apparatusincludes an elongated bodyextending longitudinally between spaced apart endsand. The apparatusincludes a plurality of body segmentsarranged along a length of the body. While eight segmentsas shown in this example, there can be any number of body segmentsdepending on the axial length of respective segments and desired length of the apparatus. The bodyof the apparatuscan have a hollow interior, which is configured to hold and/or carry an elongated flexible tubular structure (e.g., a flexible conduit). In other examples, the hollow interior (e.g., the inner periphery) of the apparatuscan itself define an elongated tubular structure into which cables can be fed and/or pulled through.

Each of the segmentsat respective endsandcan define end segments that can be coupled to an outer surface of flexible tubular structure (conduit)by end anchor couplingsandat respective end locations. The apparatuscan also include one or more segment-to-segment anchor couplingsat intermediate locations along the body. Each segment-to-segment anchor couplingis configured to attach the bodyto the conduit.

is a perspective view of part of the actuating of apparatusshowing an enlarged exploded view of an example end anchor coupling. For example, the end anchor couplingcan include two separable semi-cylindrical halvesandthat can be connected together at respective flangesand(e.g., by bolts or other fasteners). Fasteners (e.g., bolts) are used to connect the anchor to the body segment. Anchor shrouds can slide over and interlock with the end anchor to prevent soil debris from entering the machine. The anchor couplingincludes a number of slotsthat provide passages for fluid conduits (e.g., tubing)to pass through. The fluid conduitscan carry fluid for actuating respective fluidic powered actuators within one or more of the body segments. The anchor couplings,andare designed to clamp down on the conduittightly without causing non-superficial damage to the conduit.is a partial perspective view of an end of body segmentshowing a plurality of fluid conduits (e.g., tubing) extending into a respective slotof end anchor coupling. The maximum number of fluid conduits for a given slot can depend on the size of the slot relative to the size of the respective fluid conduits.

is a perspective view showing an exploded view of example segment-to-segment anchor couplingbetween an adjacent pair of body segments. For example, the segment-to-segment anchor couplingcan include two separable semi-cylindrical halvesandthat can be connected together at respective flangesand(e.g., by bolts or other fasteners). The segment-to-segment anchor couplingcan be arranged and configured to clamp down on the conduittightly without causing non-superficial damage. The segment-to-segment anchor couplingcan be connected to the end of the respective body segmentby fasteners. Anchor shrouds further can slide over and interlock with the end anchor in order to prevent soil debris from entering the fluidic actuator of the adjacent segments. The segment-to-segment anchor couplingfurther can include one or more slotsarranged and configured for the tubingto pass through the coupling between adjacent segments.

is a cross-sectional view of an example body segmentof the apparatus(taken along line-in) including a fluidic powered actuator. The apparatusthus includes a plurality of such body segmentsarranged in series along the length of the body, in which at least some of (e.g., less than all or all of) the body segments include respective fluidic powered actuators to implement peristaltic movement of the apparatus, such as described herein.

The body segmentincludes an inner periphery that defines a central lumenextending longitudinally through the plurality of body segmentsof the elongated body. The lumencan be dimensioned and configured to receive the conduitin the lumen. The conduitcan be anchored with respect to a number of segmentsof the apparatus through anchor couplings,,, as described herein.

The body segmentincludes at least first and second fluidic chambersandthat form part of the fluidic powered actuator. For example, the first and second fluidic chambersandcan be revolved around a central axisextending longitudinally through the central lumen. The first fluidic chambercan include (or define) one or more sealed chambers filled with a volume of fluid (e.g., gas or liquid). The first fluidic chamber(s)can be adapted to emulate a constant volume constraint similar to that found on biological earthworm segments to facilitate peristaltic movement of the apparatus, as described herein. In some examples, each body segmentcan include a valve coupled with the fluidic chamber, which can be used to set a pressure of the fluid within the volume such as described herein.

The second chamberdefines an actuating fluidic chamber configured to receive a change in pressure for implementing a corresponding change in axial and radial dimensions. For example, the actuating fluidic chamberis designed to be at rest or unactuated, such as shown in(e.g., corresponding to zero gauge pressure). The actuating fluidic chambercan then either receive increase or decrease in gauge pressure. In response to receiving a decrease in pressure, the actuating fluidic chambercontracts axially and expands radially, thereby causing a corresponding axial contraction and radial expansion of the respective body segment. In response to receiving an increase in pressure, the actuating fluidic chamberelongates axially and contracts radially, thereby causing a corresponding axial elongation and radial contraction of the respective body segment.

As a further example, the first fluidic chambercan include an expandable tubular outer sidewallspaced radially outwardly from a tubular inner sidewall. The tubular outer sidewalland inner sidewallof the chambercan be coupled together and spaced radially apart by respective end caps or other mounting structures, shown atand, at respective proximal and distal ends of the segment. The tubular outer sidewallthus can define a radially outer cylindrical sidewall of each body segmentof the apparatus. For example, the tubular outer structurecan include one or more layers of a flexible skin or covering (e.g., fabric or other flexible material impervious to fluid flow).

The inner sidewallof the chamberis configured to implement axial elongation and contraction. In the example of, the inner sidewallof the chamberincludes a plurality of rigid ringsthat are axially spaced apart along the length the body segmentby flexible connecting elements. The ringscan be arranged coaxially with respect to the central axis. For example, the flexible connecting elementscan be in the form of respective curved arches (or other shapes of interconnects) coupled between adjacent pairs of the rings, such as at radially outer ends thereof. The flexible connecting elementsfor a respective segmentcan be in the form of a cylindrical sheet that extends over the radially outer edge of the respective ringsand radially inwardly, forming respective arches (e.g., U-shaped elements), between adjacent pairs of rings.

As a further example, the actuating fluidic chambercan include an outer sidewall defined by the inner sidewallof the first fluidic chamberspaced radially outwardly from a second tubular inner sidewall. The inner sidewallcan be implemented as a concentric cylindrical sidewall having the same construction as the outer sidewall. For example, the inner sidewall includes a plurality of rigid ringsthat are axially spaced apart along the length the body segmentby flexible connecting elements. The flexible connecting elementscan be implemented by a substantially cylindrical sheet of flexible material that extends over the radially inner edges of the respective ringsand extends radially outwardly towards the chamber, such as forming respective arches (e.g., U-shaped elements), between adjacent pairs of rings. Proximal and distal ends of the respective sidewallsandcan be coupled together by respective end caps or other mounting structures, shown atand. In the example ofthe fluid conduitextends through the fluid chamber and the end mounting structuresand. The mounting structuresandcan be integrated with or be separate from the mounting structuresand.

By way of example, the rigid ringsandin conjunction with the flexible connecting elements (e.g., arches)andcan be configured to restrict the actuating motion of the respective sidewallsandto be the axial direction. In response to a pressure decrease within the actuating fluidic chamber, the ringsandare pulled closer together as the axial length shrinks. In response to a pressure increase within the actuating fluidic chamber, the flexible connecting elements (e.g., arches)andtend toward a flattened condition due to the pressure increase and resulting axial elongation. The rigid end arches sweep to increase the area for pressure to act towards the end caps, further promoting axial motion.

As a further example, the apparatusincludes one or more sources of pressurized fluid (e.g., positive or negative pressure) in fluid communication with the actuating fluidic chamber of at least the respective body segments. The actuator for the segment can include one or more valves coupled between the source and the actuating fluidic chamber. In the example of, in which fluid conduitsextends through the actuating fluidic chambereach fluid conduit can include one or more valves (e.g., solenoid valves) extending through the sidewall of the fluid conduitto enable an increase or decrease of pressure within the chamber responsive to activation of the valve based on a control signal. Also, or alternatively, the rigid end capsandcan include interfaces or ports for fluidic control of the actuating fluidic chamber.

A controller can be coupled to the valve(s) and configured to actuate the valve(s) to control flow of the fluid between the source and the actuating fluidic chamberto change the pressure within the actuating fluidic chamber and thereby change an axial length of the respective body segment. For example, the controller can include a microcontroller control system and pneumatic circuitry configured for controlling respective valves to switch between positive and negative pressures within the actuating fluidic chamber through selective activation of the respective valves. The controller further can coordinate the activation of the valves to implement a peristaltic waveform among respective groups of the body segments, such as described herein (see, e.g.,). In some examples, the valve includes an electromechanically operated valve (e.g., a solenoid valve) and the controller is configured to control the valve in a first state to increase pressure within the actuating fluidic chamber and cause an increase in the axial length of the respective body segment. The controller can further be configured to control the same or a different valve in a second state to decrease pressure within the actuating fluidic chamber and cause a reduction in the axial length of the respective body segment.