Monolithic Soft Actuator via Rotational Casting
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Solution Overview
Problem
Current soft robot actuator devices are limited by their inability to withstand high pressures and delamination issues, making them unreliable for applications requiring large forces and multiple actuation cycles, such as prosthetics and surgical tools.
Innovation Solution
The use of rotational casting to fabricate monolithic pneumatically powered soft actuator devices without gluing or lamination, allowing them to withstand higher pressures and apply larger forces, and enabling mass production through gravity-driven molds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional soft actuator devices use gluing or lamination to construct multi-layer structures, then device complexity is reduced and ease of manufacture is improved, but reliability deteriorates due to delamination under high pressure and repeated actuation cycles
Solution Approach 1:
The patent merges multiple layers into a single monolithic elastomeric structure fabricated by rotational casting. This eliminates the need for separate layers that would require gluing or lamination, thereby removing the delamination failure mode while maintaining structural integrity under high pressure and repeated actuation cycles.
Solution Approach 2:
The patent employs composite materials by embedding reinforcing fibers (such as nylon or Kevlar) within the elastomeric matrix during rotational casting. This creates a fiber-reinforced composite structure that provides both the flexibility of elastomers and the strength to withstand high pressures without requiring multiple laminated layers.
2Force
If soft actuator devices are designed to withstand high pressures to apply larger forces, then force output is improved, but reliability worsens due to increased risk of delamination in multi-layer structures
Solution Approach 1:
By combining all structural layers into a single monolithic elastomeric component fabricated through rotational casting, the invention eliminates delamination risks that would otherwise limit pressure承受能力. The unified structure allows the actuator to withstand high pressures (30-50 psi) necessary for generating large forces while maintaining reliability over millions of actuation cycles.
Solution Approach 2:
The fiber-reinforced elastomeric composite enables the actuator to withstand high pressures required for large force output. The embedded fibers provide tensile strength and structural support within the elastomeric matrix, allowing the device to operate at high pressures without failure while maintaining the soft, compliant characteristics needed for reliable operation.
3Reliability
If rotational casting is used to fabricate monolithic actuator devices, then reliability is improved by eliminating delamination, but manufacturing complexity increases compared to conventional methods
Solution Approach 1:
The rotational casting process utilizes fluid dynamics and centrifugal forces to evenly distribute and embed reinforcing fibers within the elastomeric precursor material during rotation. This pneumatic-hydraulic approach enables automated, scalable production of complex monolithic structures with embedded reinforcement patterns, reducing manual fabrication complexity while maintaining high 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
The solution results in actuator devices that can tolerate pressures up to 30-50 psi and survive millions of cycles without failing, while applying significant force, thus addressing the reliability and durability issues of existing devices.
Implementation Method 1
rotational casting is used to disperse the elastomeric precursor within the cavity of the mold
Implementation Method 2
rotational casting involves a hollow mold which is filled with material. The mold is then slowly rotated
Implementation Method 3
At step 210, the soft actuator device is constructed... the elastomeric precursor and the fibers
Data Source
AI summary
By rotationally casting soft robots, no bonding of different material layers is required. Soft robots including one or more integrated enclosed compartments are constructed from fibers that are embedded directly into the mold prior to adding elastomeric precursors.