Pneumatic Soft Actuators with Tunable Force-Displacement via Symmetrical Folds
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Solution Overview
Problem
Conventional pneumatic soft actuators face limitations in modifying their mechanical characteristics once constructed, with the connection geometry between the pouch and mechanical components being a potential point of failure and limiting the actuator's performance and range of motion.
Innovation Solution
A pneumatic soft actuator with an inflatable pouch featuring symmetrical folds at its ends, allowing for active modification of the end geometry through a branched tendon and spool mechanism, enabling adjustment of the force-strain relationship and range of motion without altering the pouch's composition or structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the connection geometry between the pouch and mechanical components is fixed during construction, then the actuator structure is simple and manufacturing is easy, but the mechanical characteristics and range of motion cannot be modified after construction
Solution Approach 1:
The patent implements a dynamic end geometry modification mechanism where the connection geometry between the pouch and mechanical components can be actively changed after construction. This is achieved through a system that allows the end geometry to be modified from a fixed state to a variable state, enabling the actuator to adapt its mechanical characteristics and range of motion based on operational requirements without requiring complete redesign or replacement of the actuator structure.
2Reliability
If the pouch material is made non-stretchable with woven reinforcement fibers to maintain constant surface area, then the actuator provides reliable force transmission, but the connection points become concentration points of tension and potential failure
Solution Approach 1:
The patent applies local quality by creating folds in the pouch material at the connection regions. These folds locally alter the stress distribution by redistributing the tension that would otherwise concentrate at the connection points. The folded structure provides a gradual transition zone that reduces peak stresses while maintaining the overall non-stretchable characteristic of the pouch material, thereby strengthening the connection points without compromising force transmission reliability.
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
This approach allows for precise control and modification of the actuator's mechanical characteristics, enhancing its performance and durability by altering the connection geometry between the pouch and mechanical components, thereby improving the actuator's ability to handle delicate tasks and navigate complex environments.
Implementation Method 1
Pneumatic soft actuators are linear actuators powered by air pressure to extend and/or contract along some longitudinal direction
Implementation Method 2
The pouch is typically composed of some flexible, non-stretchable material such that it retains a constant surface area as its shape changes when inflated
Implementation Method 3
Inflatable pouches with symmetrical folds at their ends enable active modification of the end geometry
Data Source
AI summary
Pneumatic soft actuators, and methods and machines capable of modifying their performance and mechanical characteristics. Such a pneumatic soft actuator can be used to connect mechanical components and include an inflatable pouch formed by an airtight, flexible, non-stretchable membrane. The inflatable pouch has oppositely-disposed ends adapted to couple to the mechanical components, and has two lateral edges in which symmetrical folds are formed and define end geometries at the ends of the inflatable pouch. Inflation and deflation of the inflatable pouch increases and decreases, respectively, a distance between the ends of the inflatable pouch to induce relative motion between the mechanical components coupled to the ends of the inflatable pouch.