Title: Hybrid vine robot with internal Steering-Reeling Mechanism enhances system-level capabilities
Continuum robots have high degrees of freedom and the ability to safely move in constrained environments. One class of soft continuum robot is the “vine” robot. This type of robot extends from its tip by everting or unfurling new material, driven by internal body pressure. Most vine robot examples store new body material in a reel at their base, passing it through the core of the robot to the tip, and like many continuum robots, steer by selectively lengthening or shortening one side of the body. While this approach to steering and material storage lends itself to a fully soft device, it has three key limitations: (i) internal friction of material passing through the core of the robot limits its length in tortuous paths, (ii) body buckling as the robot's body material is re-spooled at the base can prevent retraction, and (iii) constant curvature steering limits the robot's poses and object approach angles in a given workspace. This letter presents a hybrid soft-rigid robotic system comprising a soft vine robot body and a rigid, mobile, internal steering-reeling mechanism (SRM); this SRM is equipped with a reel for material storage, a bending actuator for steering, and is capable of actuating the robot at any point along its length. This hybrid configuration increases reach along tortuous paths, allows retraction, and increases the workspace. We describe the motivation for the device, generate its mathematical models, present its methods of operation, and verify experimentally the models we developed and the performance improvements over previous vine robots.  more » « less
Award ID(s):
1944816
PAR ID:
10294805
Author(s) / Creator(s):
; ;
Date Published:
Journal Name:
IEEE Robotics and Automation Letters
ISSN:
2377-3774
Page Range / eLocation ID:
1 to 1
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. null (Ed.)
    Soft, tip-extending "vine" robots offer a unique mode of inspection and manipulation in highly constrained environments. For practicality, it is desirable that the distal end of the robot can be manipulated freely, while the body remains stationary. However, in previous vine robots, either the shape of the body was fixed after growth with no ability to manipulate the distal end, or the whole body moved together with the tip. Here, we present a concept for shape-locking that enables a vine robot to move only its distal tip, while the body is locked in place. This is achieved using two inextensible, pressurized, tip-extending, chambers that "grow" along the sides of the robot body, preserving curvature in the section where they have been deployed. The length of the locked and free sections can be varied by controlling the extension and retraction of these chambers. We present models describing this shape-locking mechanism and workspace of the robot in both free and constrained environments. We experimentally validate these models, showing an increased dexterous workspace compared to previous vine robots. Our shape-locking concept allows improved performance for vine robots, advancing the field of soft robotics for inspection and manipulation in highly constrained environments. 
    more » « less
  2. null (Ed.)
    Soft, tip-extending, pneumatic “vine robots” that grow via eversion are well suited for navigating cluttered environments. Two key mechanisms that add to the robot’s functionality are a tip-mounted retraction device that allows the growth process to be reversed, and a tip-mounted camera that enables vision. However, previous designs used rigid, relatively heavy electromechanical retraction devices and external camera mounts, which reduce some advantages of these robots. These designs prevent the robot from squeezing through tight gaps, make it challenging to lift the robot tip against gravity, and require the robot to drag components against the environment. To address these limitations, we present a soft, pneumatically driven retraction device and an internal camera mount that are both lightweight and smaller than the diameter of the robot. The retraction device is composed of a soft, extending pneumatic actuator and a pair of soft clamping actuators that work together in an inch-worming motion. The camera mount sits inside the robot body and is kept at the tip of the robot by two low-friction interlocking components. We present characterizations of our retraction device and demonstrations that the robot can grow and retract through turns, tight gaps, and sticky environments while transmitting live video from the tip. Our designs advance the ability of everting vine robots to navigate difficult terrain while collecting data. 
    more » « less
  3. null (Ed.)
    The field of soft robotics is grounded on the idea that, due to their inherent compliance, soft robots can safely interact with the environment. Thus, the development of effective planning and control pipelines for soft robots should incorporate reliable robot-environment interaction models. This strategy enables soft robots to effectively exploit contacts to autonomously navigate and accomplish tasks in the environment. However, for a class of soft robots, namely vine-inspired, tip-extending or "vine" robots, such interaction models and the resulting planning and control strategies do not exist. In this paper, we analyze the behavior of vine robots interacting with their environment and propose an obstacle-interaction model that characterizes the bending and wrinkling deformation induced by the environment. Starting from this, we devise a novel obstacle-interaction planning method for these robots. We show how obstacle interactions can be effectively leveraged to enlarge the set of reachable workspace for the robot tip, and verify our findings with both simulated and real experiments. Our work improves the capabilities of this new class of soft robot, helping to advance the field of soft robotics. 
    more » « less
  4. Soft robots excel in adaptability, and rigid robots in precise, forceful actuation, yet each faces limitations that reduce performance in cluttered or constrained settings. We address these gaps by enabling physical coupling between a soft Vine robot and centimeter-scale RESCUE roller robots, allowing heterogeneous teams to work cooperatively to leverage each other’s strengths. Our approach improves mobility, enables power sharing, and communication through mechanical interfaces, modular chain formation, and high-speed recharging and data transfer via electrical contact using magnetic connectors. RESCUE rollers can form chains for collaborative locomotion and load distribution, and seamlessly integrate with the Vine robot to extend its workspace. In return, the Vine robot serves as a mobile power and communication hub, recharging rollers and relaying data to extend operational time. Experimental validation includes measurements of pushing and pulling strength in roller chains (Section III-A), Vine robot buckling under load (Section III-B), and demonstrations of Vine robot and RESCUE rollers interactions in a cluttered environment (Section IV-A), tight turning of the Vine robot using rollers (Section IV-B), and in-field recharging of RESCUE rollers (Section IV-C). This work advances cooperative strategies for heterogeneous robotic systems, enabling adaptable and resilient performance in challenging environments. 
    more » « less
  5. Rehabilitation of aging pipes requires accurate condition assessment and mapping far into the pipe interiors. Soft growing vine robot systems are particularly promising for navigating confined, sinuous paths such as in pipes, but are currently limited by complex subsystems and a lack of validation in real-world industrial settings. In this paper, we introduce the concept and implementation of a hermetic and transparent vine robot system for visual condition assessment and mapping within non-branching pipes. This design encloses all mechanical and electrical components within the vine robot’s soft, airtight, and transparent body, protecting them from environmental interference while enabling visual sensing. Because this approach requires an enclosed mechanism for transporting sensors, we developed, modeled, and tested a passively adapting enclosed tip mount. Finally, we validated the hermetic and transparent vine robot system concept through a real-world condition assessment and mapping task in a wastewater pipe. This work advances the use of soft-growing vine robots in pipe inspection by developing and demonstrating a robust, streamlined, field-validated system suitable for continued development and deployment. 
    more » « less