Robotic actuator
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Solution Overview
Problem
Current bellows-based actuators are limited by their inability to hold high pressures or apply large forces relative to their weight, often requiring excessive elastomeric materials or combining materials with tensile fibers, resulting in poor range of motion, force profiles, and high costs.
Innovation Solution
The development of mass-manufactured bellows with localized bending capabilities, formed from materials with higher strength in at least two axes, and the use of fluidic actuators with controlled pressure and volume changes to achieve force or movement, allowing for a range of motion and strength optimization through geometry and material properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional elastomeric bellows are used to create actuation, then the structure is simple and easy to manufacture, but the actuator cannot hold high pressures or apply large forces relative to its weight
Solution Approach 1:
The bellows is constructed from composite materials including a porous substrate layer and a fluid-impermeable membrane layer, creating a structure that can contain fluid pressure while maintaining lightweight properties. This composite structure enables high force output relative to the actuator's weight by combining the structural integrity of the porous substrate with the pressure-containing capability of the membrane.
Solution Approach 2:
The bellows incorporates localized convolutions or folds at specific regions to enable bending and range of motion while maintaining structural strength in other areas. This localized flexibility allows the actuator to achieve complex dynamic properties without compromising overall structural integrity or requiring excessive material.
2Force
If excessive elastomeric materials are used to carry large forces, then the actuator can apply large forces, but the range of motion becomes poor and the actuator becomes heavier
Solution Approach 1:
The bellows incorporates localized convolutions or folds at specific regions to enable bending and range of motion while maintaining structural strength in other areas. This localized flexibility allows the actuator to achieve complex dynamic properties without compromising overall structural integrity or requiring excessive material.
Solution Approach 2:
The actuator design allows the bellows to dynamically adjust its shape and configuration during operation, transitioning between extended and contracted states with controlled bending. This dynamic capability enables both high force output and substantial range of motion by allowing the structure to adapt its rigidity and flexibility as needed.
3Force
If elastomeric material is combined with tensile fibers to create contractile movement, then the actuator can generate force, but the force profile becomes poor and the cost increases
Solution Approach 1:
The actuator uses pneumatic or hydraulic fluid pressure applied to the porous substrate to generate contractile movement. The fluid pressure causes the porous substrate to expand, which in turn actuates the bellows to contract or extend. This fluidic actuation method provides smooth force profiles and programmable motion characteristics while avoiding the need for complex fiber reinforcement structures.
Solution Approach 2:
The design replaces traditional mechanical fiber-reinforced elastomeric systems with a fluidic actuation system. Instead of relying on tensile fibers to create contractile movement, the system uses fluid pressure applied to the porous substrate to generate motion, simplifying the structure and reducing manufacturing costs while improving force profiles.
4Adaptability or versatility
If fluidic actuators with controlled pressure and volume changes are used, then force and range of motion are improved, but the device complexity increases
Solution Approach 1:
The porous substrate serves multiple functions simultaneously: it contains the fluid pressure, provides structural support, enables bending and range of motion through its flexible nature, and transfers the fluid pressure to the bellows actuation mechanism. This multi-functionality reduces the need for separate components and simplifies the overall device structure while maintaining advanced control capabilities.
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 solution enables the creation of lightweight, cost-effective robotic actuators with improved force profiles and range of motion, capable of complex dynamic properties and versatile applications, including serial manipulators with six degrees of freedom.
Implementation Method 1
The porous substrate allows fluid to pass through it to reach the membrane
Implementation Method 2
The membrane is stretched by fluid pressure to create actuator movement or force
Implementation Method 3
The membrane is stretched by fluid pressure
Data Source
AI summary
A robotic actuator comprises a mass manufactured bellows, wherein the mass manufactured bellows allows a volume change by localized bending, and wherein the mass manufactured bellows is formed from a material that has a higher strength in at least two axes relative to at most one other axis, and an end effector, wherein the end effector is coupled to the manufactured bellows.