# US 11,897,129 B2 · Continuum robots with multi-scale motion through equilibrium modulation

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- Number: US 11,897,129 B2
- Document ID: US11897129B2
- Status: Granted
- Kind: B2
- Application number: 17/187,534
- Filed: 2021-02-26
- Published: 2021-07-08
- Granted: 2024-02-13
- Earliest claimed: 2017-09-13
- Assignees: Vanderbilt University
- Applicants: Vanderbilt University
- Inventors: Nabil Simaan; Giuseppe Del Giudice; Long Wang; Karen M. Joos; Jin-Hui Shen
- Web page: https://patentgrep.com/patent/US11897129B2

## CPC

- B25J 9/065: {Snake robots}
- B25J 9/0009: {Constructional details, e.g. manipulator supports, bases}
- B25J 9/104: {with cables, chains or ribbons}
- B25J 9/123: {Linear actuators}
- B25J 9/161: {Hardware, e.g. neural networks, fuzzy logic, interfaces, processor}
- B25J 9/1625: {Truss-manipulator for snake-like motion}
- B25J 9/1635: {flexible-arm control}
- B25J 18/06: flexible
- B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50})

## Abstract

A robotic system, such as a continuum robot, that includes at least one hollow tube backbone and an equilibrium modulation wire at least partially positioned within the backbone. The robotic system is configured to adjust a position of an end effector by bending the hollow tube and to further adjust the position of the robotic device by adjusting a linear insertion position of the equilibrium modulation wire inside the hollow tube, wherein adjusting the linear insertion position of the equilibrium modulation wire changes a flexural rigidity of the hollow tube resulting in a change in the resulting bending angle of the robotic device.

## Claims

### Claim 1

A continuum robot comprising:
a hollow tube,
wherein the hollow tube is rigid and bendable, and
wherein the continuum robot is operable to cause a controllable bending movement of the hollow tube to adjust a pose of the continuum robot; and
an equilibrium modulating wire slidably positioned inside the hollow tube, wherein linear movement of the equilibrium modulating wire relative to the hollow tube controllably alters a flexural rigidity of the hollow tube.

### Claim 2 (depends on 1)

The continuum robot of claim 1, wherein retracting the equilibrium modulating wire from the hollow tube reduces a flexural rigidity of the hollow tube.

### Claim 3 (depends on 1)

The continuum robot of claim 1, wherein a bending force applied to the hollow tube causes a first bending movement when the equilibrium modulating wire is inserted inside the hollow tube, and wherein the same bending force applied to the hollow tube causes a second bending movement when the equilibrium modulating wire is at least partially retracted from the hollow tube, wherein the second bending movement has a greater bending magnitude than the first bending movement.

### Claim 4 (depends on 1)

The continuum robot of claim 1, further comprising a robot actuator configured to
controllably apply a bending force to the hollow tube, and
controllably adjust linear movement of the equilibrium modulating wire.

### Claim 5 (depends on 4)

The continuum robot of claim 4, further comprising an electronic controller configured to control movement of the hollow tube by providing control signals to the robot actuator, wherein the electronic controller is configured to:
determine a target pose for the hollow tube;
determine a target bending force and a target linear position of the equilibrium modulating wire relative to the hollow tube needed to move the hollow tube to the target pose; and
operate the robot actuator to move apply the target bending force to the hollow tube and to move the equilibrium modulating wire to the target linear position.

### Claim 6 (depends on 4)

The continuum robot of claim 4, further comprising an electronic controller configured to control movement of the hollow tube by providing control signals to the robot actuator, wherein the electronic controller is configured to:
operate the robot actuator under macro-scale control by adjusting the bending force applied to the hollow tube until the hollow tube bends to an intermediate position within a threshold distance of a target position; and
operate the robot actuator under micro-scale control by adjusting a linear position of the equilibrium modulating wire until the hollow tube bends from the intermediate position to the target position.

### Claim 7 (depends on 4)

The continuum robot of claim 4, further comprising a bendably articulatable body including the hollow tube, wherein the hollow tube is positioned along at least part of a length of the bendably articulatable body.

### Claim 8 (depends on 7)

The continuum robot of claim 7, wherein the bendably articulatable body further includes a bendable, rigid central backbone, and wherein the robotic actuator is configured to apply the bending force to the hollow tube by controllably adjusting a linear movement of the hollow tube relative to the central backbone.

### Claim 9 (depends on 8)

The continuum robot of claim 8, wherein the bendably articulatable body further includes a control disk, wherein the central backbone is fixedly coupled to a center of the control disk, wherein the hollow tube is fixedly coupled to the control disk at a defined distance from the center of the control disk such that linear movement of the hollow tube relative to a base of the continuum robot causes a bending movement of the bendably articulatable body, and wherein the bendably articulatable body is configured such that the bending movement of the bendably articulable body causes corresponding bending movements of the central backbone and of the hollow tube.

### Claim 10

A system comprising:
a bendably articulatable body including
a control disk,
a bendable, rigid central backbone fixedly coupled to a center of the control disk, and
a secondary backbone fixedly coupled to the control disk at a defined distance from the center of the control disk,
wherein the movement actuator is configured to adjustably apply the bending force to the bendably articulatable body by controllably adjusting a linear position of a proximal end of the secondary backbone relative to a proximal end of the central backbone; and
a movement actuator configured to
controllably adjust a bending movement of the bendably articulatable body through direct actuation by adjustably applying a bending force to the bendably articulatable body, and
controllably adjust the bending movement of the bendably articulatable body through indirect actuation by controllably adjusting a flexural rigidity of the bendably articulatable body.

### Claim 11 (depends on 10)

The system of claim 10, wherein the bendably articulatable body includes
a hollow tube, and
an equilibrium modulating wire slidably positioned inside the hollow tube,
wherein the movement actuator is configured to controllably adjust the flexural rigidity of the bendably articulatable body by controllably adjusting a linear position of the equilibrium modulating wire relative to the hollow tube.

### Claim 12 (depends on 10)

The system of claim 10, wherein the movement actuator is configured to controllably adjust the flexural rigidity of the bendably articulatable body by adjustably applying thermal energy to at least a portion of the bendably articulatable body.

### Claim 13 (depends on 10)

The system of claim 10, wherein the bendably articulatable body includes a hollow tube at least partially filled with a gaseous or fluid medium, and wherein the movement actuator is configured to controllably adjust the flexural rigidity of the bendably articulatable body by controllably adjusting an internal pressure of the gaseous or fluid medium inside the hollow tube.

### Claim 14

A system comprising:
a bendably articulatable body;
a movement actuator configured to
controllably adjust a bending movement of the bendably articulatable body through direct actuation by adjustably applying a bending force to the bendably articulatable body, and
controllably adjust the bending movement of the bendably articulatable body through indirect actuation by controllably adjusting a flexural rigidity of the bendably articulatable body; and
an electronic controller configured to control movement of the bendably articulatable body by providing control signals to the movement actuator, wherein the electronic controller is configured to:
operate the movement actuator under macro-scale control by adjusting the bending force applied to the bendably articulatable body until the bendably articulatable body bends to an intermediate position within a threshold distance of a target position, and
operate the movement actuator under micro-scale control by adjusting the flexural rigidity of the bendably articulatable body until the bendably articulatable body bends from the intermediate position to the target position.

### Claim 15

A method of adjustably controlling a pose of a bendably articulatable body, the method comprising:
controllably adjusting a bending movement of the bendably articulatable body through direct actuation by adjustably applying a bending force to the bendably articulatable body;
controllably adjust the bending movement of the bendably articulatable body through indirect actuation by controllably adjusting a flexural rigidity of the bendably articulatable body, and
wherein the bendably articulatable body includes a hollow tube and an equilibrium modulating wire slidably positioned inside the hollow tube, and
wherein controllably adjusting the flexural rigidity of the bendably articulatable body includes controllably adjusting a linear position of the equilibrium modulating wire relative to the hollow tube.

### Claim 16 (depends on 15)

The method of claim 15, wherein controllably adjusting the flexural rigidity of the bendably articulatable body includes adjustably applying thermal energy to at least a portion of the bendably articulatable body.

### Claim 17 (depends on 15)

The method of claim 15, wherein the bendably articulatable body includes a hollow tube at least partially filled with a gaseous or fluid medium, and wherein controllably adjusting the flexural rigidity of the bendably articulatable body includes controllably adjusting an internal pressure of the gaseous or fluid medium inside the hollow tube.

### Claim 18 (depends on 15)

The method of claim 15, wherein the bendably articulatable body includes a control disk, a bendable rigid central backbone fixedly coupled to a center of the control disk, and a secondary backbone fixedly coupled to the control disk at a defined distance from the center of the control disk,
wherein adjustably applying the bending force to the bendably articulatable body includes controllably adjusting a linear position of a proximal end of the secondary backbone relative to a proximal end of the central backbone.

### Claim 19 (depends on 15)

The method of claim 15, further comprising determining a target position for the bendably articulatable body,
wherein controllably adjusting the bending movement of the bendably articulatable body through direct actuation includes adjusting the bending force applied to the bendably articulatable body until the bendably articulatable body bends to an intermediate position within a threshold distance of a target position, and
wherein controllably adjusting the bending movement of the bendably articulatable body through indirect actuation includes adjusting the flexural rigidity of the bendably articulatable body until the bendably articulatable body bends from the intermediate position to the target position.
