Vine Robots: Design, Teleoperation, and Deployment for Navigation and Exploration

Motivation

• Pneumatically everting vines grow by turning their flexible tubular body inside out at the tip, enabling lengthening without body-relative motion and offering flexibility for tortuous paths and rigidity to bridge gaps.Vine robots are proposed for constrained-space applications including inspection, search and rescue, medicine, and archaeology; their bodies can deliver payloads and their air-pressure-driven motion avoids ignition risks from electrical failure. They have also traversed sticky, slippery, and sharp environments and grown into structures.Source: BACKGROUND · p. 1

Contributions

• The work presents a complete, portable, steerable vine robot system with a camera that grows to arbitrary length from a compact form, and reports field deployments at a navigation competition and an archaeological site.The competition involved uneven terrain, unstable obstacles, and a small aperture; the archaeological site involved rocks and horizontal and vertical turns.Source: BACKGROUND · pp. 1–2
• A reversible, body-length steering actuator can be heat-sealed, attached with double-sided tape, and manufactured at long lengths.The design improves on actuators in,.Source: BACKGROUND · p. 1
• A compact tip camera mount uses a rigid cap and zipper pocket to manage the camera wire while allowing growth from a compact base to arbitrary length.The design contrasts with bulky, limited-length, and wireless camera approaches,,,,.Source: BACKGROUND · p. 1
• The system controls growth speed by restricting growth with a motor and enables human-in-the-loop teleoperation through a flexible joystick and geometric model-based steering.The growth controller prevents loss of control if motor speed exceeds pressure-driven growth speed; teleoperation adapts devices and pressure mapping from,,.Source: BACKGROUND · pp. 1–2

VINE ROBOT SYSTEM REQUIREMENTS

• The requirements were derived from basic vine-robot functionality, operation in unpredictable environments, and the intended field navigation and exploration deployments.Source: VINE ROBOT SYSTEM REQUIREMENTS · p. 2

Soft Robot Navigation Competition Scenario

• The 9.5 m RoboSoft 2018 course tested traversal of sand, stairs, an aperture, and unstable cylinders, with scoring based on task completion and obstacle handling.Source: Soft Robot Navigation Competition… · p. 2

Archaeological Exploration Scenario

• At Chavin, the robot was invited to explore tight archaeological spaces that people or camera sticks could not readily reach; underground tunnels span about 30–100 cm and can extend hundreds of meters.Exploration could help locate rooms or objects of interest and map tunnel shapes to inform understanding of their purpose or significance.Source: Archaeological Exploration Scenario · p. 2

Summary of Design Requirements

• A pneumatic vine robot body must use flexible, non-stretchable material that can turn inside out at the tip and contain pressurized air.Source: Summary of Design Requirements · p. 2
• Effective teleoperation requires controllable growth and steering, a human-input interface, and a way to observe the robot tip’s position.Source: Summary of Design Requirements · p. 2
• The system must grow to navigation-relevant lengths, pass through small apertures, and support its body weight when moving vertically or over floor gaps.Source: Summary of Design Requirements · p. 2
• Field use requires portability, mechanical and electrical robustness for a competition run or a week of archaeological testing, and practical speed; archaeological exploration also requires data recording.Source: Summary of Design Requirements · p. 2
• Table I summarizes the requirements alongside the design solutions selected for the two deployed robot versions.Source: Summary of Design Requirements · p. 2

SYSTEM OVERVIEW

• The vine robot system is teleoperated using visual feedback from a camera at its tip, is portable, and is not inherently limited in length.The complete system comprises the growing robot portion, base station, and human interface.Source: SYSTEM OVERVIEW · p. 2
• The complete system consists of the growing portion of the robot, a base station, and a human interface for control.Source: SYSTEM OVERVIEW · p. 2
• Table II lists design specifications for two robot versions, which are described alongside the relevant system components.Source: SYSTEM OVERVIEW · p. 2
• Soft robot body material stored on a spool inside the base enables the robot to grow to arbitrary length.The camera cap is pushed along as the body grows.Source: Figure 1 · p. 3
• Series pouch motor soft pneumatic actuators running along the robot body enable reversible steering of the tip.Source: Figure 1 · p. 3
• A rigid cap carries a wired camera at the tip, while a pocket running along the body contains its wires as the robot grows.Source: Figure 1 · p. 3

Soft Robot Body Design

• The soft body uses one flexible, nonstretchable central tube surrounded by three smaller actuator tubes spaced around its circumference.The four tubes are airtight; the actuators attach lengthwise to the central body.Source: Soft Robot Body Design · pp. 3–4
• Pressurizing the main tube while material unrolls from an internal spool makes the body elongate from its tip.The tube is folded inside itself around the spool in a rigid pressure vessel, storing a long body length compactly.Source: Soft Robot Body Design · p. 3, Figure 4 · p. 4
• The competition robot body used thin airtight plastic tubing, while the archaeological exploration robot used thin airtight fabric.The plastic was available in tube form for rapid prototyping and manufacturing; the passage’s explanation for choosing fabric is truncated.Source: Soft Robot Body Design · p. 3
• Three series pouch-motor actuators shorten when pressurized, curving the body toward the active actuator; their design builds on pouch motors and series pneumatic muscles,.The actuators are attached with double-sided tape, and their arrangement is suited to long lengths and easy attachment.Source: Soft Robot Body Design · p. 4, Figure 3 · p. 4

Base Station Design

• A motor-driven spool and encoder control body-material release during growth and assist retraction, while a string attached to the distal end helps pull the body back.The archaeological base had a larger diameter to accommodate thicker body material.Source: Base Station Design · p. 4, Figure 4 · p. 4
• The base station uses four closed-loop pressure regulators, an Arduino-based control system, a portable compressor, and a fail-closed valve for rapid pressure release.High-flow pneumatic components were selected, but the compressor limited the system’s overall maximum flow rate.Source: Figure 2 · p. 3, Base Station Design · p. 5
• Wired connections and no battery-powered components support continuous field operation when power lines are available.The solenoid valve allows quick release of system pressure in an emergency or power failure.Source: Base Station Design · p. 5

Flexible Joystick Design

• The joystick’s long, thin, bendable form mimics the vine robot’s soft body to support intuitive steering.It is made from 3D-printed flexible rubber, and an onboard IMU measures tip orientation.Source: Flexible Joystick Design · p. 5
• An IMU controls steering, while a rotary potentiometer sets main-body pressure and a sliding potentiometer sets motor speed for growth.The joystick also includes an emergency-stop toggle switch.Source: Flexible Joystick Design · p. 5

Camera Mount Design

• A rigid, bullet-shaped cap carried a wide-angle camera and surrounding LED lights, sliding along the robot body as it grew to support exploration and video recording.Its inner diameter was 10.4 cm, and the lens captured approximately 120° of the environment without moving.Source: Camera Mount Design · p. 5, Figure 7 · p. 6
• A wired camera suited underground exploration, with its cable pulled from the robot base through an LDPE pocket that lengthened via a zipper as the body grew.The zipper head was fixed to the camera cap, so the pocket extended with the robot while keeping the wire from directly contacting the environment.Source: Camera Mount Design · p. 5, Figure 7 · p. 6
• The zipper prevented the camera cap from rotating relative to the robot body, simplifying the mapping between camera-image movement and actuator movement.Source: Camera Mount Design · p. 6

• Growth and steering are controlled independently and occur simultaneously.Source: CONTROL · p. 6
• The Arduino maps and scales joystick inputs into motor voltage and four pressures that control the robot body.Source: CONTROL · p. 6
• Without robot-shape sensing, the operator closes the loop through line-of-sight or camera feedback to reach a desired tip position.Source: CONTROL · p. 6

• Main-body pressure is set by a potentiometer and maintained by a closed-loop regulator receiving an analog voltage derived from an Arduino PWM signal.Source: Growth Control · p. 6
• Motor direction and speed are commanded with a direction switch and speed potentiometer, while encoder-based proportional-integral control maintains the desired motor speed.Source: Growth Control · p. 6
• Backdrivable motor restraint preserves tension and controllability by preventing material from unspooling too quickly during growth.Smooth growth requires pressure above the growth threshold and motor-maintained tension; maximum growth pressures were 14 kPa for the competition robot and 21 kPa for the archaeology robot, and maximum observed growth speed was approximately 10 cm/s for both systems.Source: Growth Control · p. 6

Steering Control

• Joystick-tip IMU orientation is converted to curvature and bending direction, then to a matching robot-tip target enacted by three pressure regulators using geometric models,,.Only the distal approximately 1 meter was operator-controllable because of the body’s weight, resulting in approximately the same tip movement at different body lengths.Source: Steering Control · pp. 6–7
• To resolve three-actuator redundancy for two steering degrees of freedom, pressures are iteratively chosen to remain positive while keeping at least one near zero, avoiding unnecessary co-contraction.Maximum steering pressure was 14 kPa for the competition robot and 21 kPa for the archaeology robot.Source: Steering Control · p. 7

Deployment at a Soft Robot Navigation Competition

• The vine robot was the only competition entrant to navigate all four obstacles perfectly on its first attempt and passed the smallest aperture, but finished third after receiving half points on the first three obstacles.The scoring penalized robots that did not move their whole body through each obstacle.Source: Steering Control · p. 7
• In practice, operators completed the course in under three minutes at 6 cm per second and passed a 4 cm aperture despite a 7 cm inflated body diameter.The body shrinking ratio was 0.57:1; smaller apertures caused buckling or wall-sliding. The robot crossed the sandpit without pushing against the ground and grew over stairs, but slid one unstable cylinder aside because it could not make a tight S-curve without environmental support.Source: Steering Control · p. 7
• At competition, a broken regulator required hand control of main-body pressure, while a leak emptied the compressor tank three times; the robot completed the course in 13 minutes and 28 seconds.The leak exceeded the compressor’s maximum flow rate of 470 cubic centimeters per second, requiring pauses in growth while the tank refilled.Source: Steering Control · p. 7

DEPLOYMENT AT AN ARCHAEOLOGICAL SITE

• Three archaeological locations were selected for archaeological interest, difficulty of access by other means, and expected tunnel lengths under 10 m from human-sized entrances.Ease of setting up the robot at the entrance was also a selection consideration.Source: DEPLOYMENT AT AN ARCHAEOLOGICAL SITE · p. 7
• The robot accessed all three tunnels, recording otherwise unavailable video after passing a rock blockage, rounding a 90° turn, and growing up a shaft to approximately 6 m, 5 m, and 3 m, respectively.These movements occurred in Locations 1, 2, and 3, respectively.Source: DEPLOYMENT AT AN ARCHAEOLOGICAL SITE · p. 8
• Deployment exposed slow growth, actuator leaks, a rigid camera cap, inability to retract within tunnels, and poor situational awareness during tip-camera teleoperation.Long, narrow pressure tubing reduced growth speed; repeated use opened actuator heat seals. The camera cap impeded growth along walls and through narrow apertures, while retraction caused buckling. Camera roll and difficulty judging the tip’s distance and direction confused teleoperation.Source: DEPLOYMENT AT AN ARCHAEOLOGICAL SITE · p. 8

• Two versions of the field-ready vine robot system successfully navigated the RoboSoft 2018 competition course and explored an archaeological site in Chavin, Peru.Source: DISCUSSION AND FUTURE WORK · p. 8
• The robot handled obstacles, stairs, and a small aperture well, but growth-based movement incurred a competition scoring penalty and may be unsuitable when leaving the body behind is undesirable.Its body could be useful as a conduit for fluids and electrical signals.Source: DISCUSSION AND FUTURE WORK · p. 8
• At the archaeological site, the robot navigated rocks, curves, vertical shafts, and tortuous tunnels from a compact form, but occlusion made exploration harder than course completion.Transporting sensors without hindering shape change or growth over obstacles remains an open question.Source: DISCUSSION AND FUTURE WORK · p. 8
• Future work includes carrying cameras or other sensors without impeding growth, retracting the robot without buckling, and improving operator awareness when the tip is occluded.Source: DISCUSSION AND FUTURE WORK · pp. 8–9
• Further research could extend navigation into more restricted spaces through burrowing and use the growing robot body as a conduit for transporting material.The authors aim to advance nondestructive exploration of small spaces.Source: DISCUSSION AND FUTURE WORK · p. 9
• To make vine robot designs accessible, the authors created a website with instructions for making pneumatically everting robots without active steering and plan to add other designs and control software.Source: DISCUSSION AND FUTURE WORK · p. 9