Programmable Elastomer Robot With 3D Helical Radial Constraint
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Solution Overview
Problem
Current elastomer robots, such as pneumatic elastomer actuators (PEAs), face challenges in behavior tuning, fabrication complexity, and limited ability to tune actuation behaviors for confined space applications, due to issues like radial expansion and manual fabrication errors.
Innovation Solution
A programmable elastomer robot with a 3D printed quad-helical internal structure and a flexible external structure, allowing for tunable stiffness and actuation behavior through directional adjustments and pre-programmed parameters, simplifying fabrication and reducing manual errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If elastomer thickness is increased to improve stiffness and control bending behavior, then bending precision is improved, but radial expansion increases making the robot unsuitable for confined spaces
Solution Approach 1:
The robot is divided into two distinct structures: an internal structure made of stiff material (e.g., 3D-printed plastic) and an external elastomer structure. The internal structure provides the primary bending control with precise geometry, while the external elastomer provides compliance and protection without contributing significantly to radial expansion. This segmentation allows independent optimization of each component's function.
Solution Approach 2:
The robot combines dissimilar materials with complementary properties: a stiff internal structure (e.g., PLA, ABS, or resin 3D-printed materials) and a compliant external elastomer (e.g., silicone rubber). This composite construction allows the stiff internal structure to control bending precision while the elastomer provides safety and compliance, eliminating the trade-off between thickness/stiffness and radial expansion.
2Manufacturing precision
If manual fiber wrapping is used to limit radial strain, then radial constraint is improved, but fabrication complexity and time increase significantly
Solution Approach 1:
The manual mechanical process of wrapping fibers around the elastomer is replaced with an automated 3D printing process. The internal structure is printed directly in the desired helical or spiral configuration, eliminating the need for manual fiber placement, tensioning, and wrapping. This substitution dramatically reduces fabrication complexity while maintaining or improving radial constraint precision.
Solution Approach 2:
The fabrication method transitions from manual fiber wrapping with variable parameters (fiber angle, tension, wrap density) to 3D printing with precisely controllable digital parameters (helix angle, coil density, filament diameter). This parameter standardization eliminates human error and reduces fabrication variability while simplifying the process.
3Ease of operation
If separate axial and radial strain-limiting layers are added to control PEA behavior, then actuation control is improved, but fabrication simplicity is lost
Solution Approach 1:
The functions of axial and radial strain limitation are merged into a single 3D-printed internal structure. The helical or spiral geometry of the internal structure simultaneously provides both radial constraint (preventing elastomer ballooning) and axial strain limitation (controlling extension behavior). This eliminates the need for separate limiting layers and their associated complex multi-step fabrication processes.
Solution Approach 2:
The internal structure serves multiple functions simultaneously: it provides radial constraint, axial strain limitation, bending control, and structural support. This multi-functional design eliminates the need for multiple specialized components, simplifying fabrication while maintaining comprehensive actuation control.
4Manufacturing precision
If fiber helices are wrapped manually to prevent diameter increase, then radial constraint is improved, but fabrication time increases to around 3 hours with human errors
Solution Approach 1:
The time-consuming manual mechanical wrapping process is replaced with automated 3D printing. The internal structure is printed directly in the desired configuration in a single continuous process, reducing fabrication time from hours to minutes while eliminating human errors in fiber placement and tension control.
Solution Approach 2:
The 3D printing process is self-contained and automated, requiring no manual intervention during fabrication. The printer automatically deposits material layer by layer to create the precise internal structure geometry, eliminating the need for human operators to perform repetitive wrapping tasks and reducing fabrication time significantly.
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 precise control over bending and extension behaviors, reducing radial expansion and simplifying fabrication, thereby enhancing the robots' utility in confined spaces and improving their tunability and reliability.
Implementation Method 1
pneumatic elastomer actuators (PEAs)
Implementation Method 2
elastomer thickness tuning is a simple approach to preprogramming bending and extension behavior of PEAs
Data Source
AI summary
An elastomer robot comprises a flexible internal structure comprising a first flexible material, wherein the internal structure is tunable, and a flexible external structure comprising a second flexible material, attached to the internal structure, including an aperture configured to accept a fluid, wherein the external structure is tunable. Methods of use and production are also disclosed.