Soft Growing Robot Retraction Mechanism Prevents Buckling
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Solution Overview
Problem
Existing soft growing robots face challenges in controlling the motion and forces during retraction, as the soft robot body tends to buckle, especially after growing to long lengths or into curved shapes.
Innovation Solution
A double-walled flexible tubular robot with a retraction device located at the folded tip, featuring a routing aperture and a retraction mechanism, such as motor-driven rollers or a grasping mechanism, to controllably retract the inside wall and prevent buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the soft robot body grows to long lengths or into curved shapes, then the robot's length and navigation capability are improved, but the robot body becomes prone to buckling during retraction
Solution Approach 1:
The robot body is divided into two separate walls: an inside wall and an outside wall. During retraction, the inside wall is independently pulled back through the retraction device, while the outside wall remains stationary or moves differently. This segmentation allows differential motion between the two walls, preventing the buckling that occurs when a single unified body is retracted as a whole.
2Length of moving object
If retraction force is applied to shorten the robot, then the robot's length is reduced, but uncontrollable bending and buckling occur
Solution Approach 1:
A retraction device is introduced as an intermediary mechanism between the inside wall and the pulling force. This device includes a routing aperture and retraction mechanism that guides and controls the motion of the inside wall during retraction. The intermediary device ensures that the inside wall is pulled back in a controlled manner, preventing uncontrolled bending and buckling of the robot body.
3Length of moving object
If the inside wall is pulled back during retraction, then the robot shortens, but the outside wall cannot maintain its shape
Solution Approach 1:
The robot body is divided into two separate walls: an inside wall and an outside wall. During retraction, the inside wall is independently pulled back through the retraction device, while the outside wall remains stationary or moves differently. This segmentation allows differential motion between the two walls, preventing the buckling that occurs when a single unified body is retracted as a whole.
Solution Approach 2:
The robot employs flexible wall structures that can accommodate differential motion between the inside and outside walls during retraction. The flexibility of these shell structures allows them to deform appropriately as the inside wall is pulled back, maintaining structural integrity and preventing buckling while enabling length reduction.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables controlled retraction of soft growing robots without buckling, allowing for precise navigation and interaction, and enabling the removal of the robot without damaging the environment.
Implementation Method 1
two parallel aligned motor-driven rollers with sufficient spacing for the inside wall, and wherein the parallel aligned motor-driven rollers retract the inside wall by rolling in opposite directions from each other and as such squeezing the inside wall as it is passed between the parallel aligned motor-driven rollers
Data Source
AI summary
Technology is provided for controlling the motion of soft growing robots during retraction to prevent uncontrollable buckling or bending. A double walled flexible tubular robot is provided with an inside wall, an outside wall, and a folded tip. A retraction device located at the folded tip has a routing aperture sized to encompass the inside wall and for routing the inside wall through the retraction device. The retraction device further has a retraction mechanism inside the retraction device to controllably retract material of the inside wall through the routing aperture in the direction away from the folded tip, thereby decreasing the outside wall, creating more inside wall, and as such shortening the length of the flexible robot. This technology enables behaviors, such as (1) growing in one direction, and then retracting and growing in a different direction, and (2) retracting through a confined space without applying force to the environment.