Soft Robotic Spiral Gripper with Embedded Fiber Optic Sensor
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Solution Overview
Problem
Existing soft robotic grippers require a large operation space to access target objects, and there is a lack of effective sensors for accurate pneumatic control and external disturbance detection, which limits their functionality in confined environments.
Innovation Solution
A pneumatic soft robotic spiral gripper with an embedded high-birefringence fiber optic sensor that mimics the twining motion of plants, allowing for precise sensing of twining angle and target diameter, and using a harder elastic spine to minimize operation space and prevent delamination, enabling secure gripping in confined areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a soft robotic gripper uses soft and elastic materials to mimic complex motions, then adaptability and versatility are improved, but device complexity increases
Solution Approach 1:
The gripper employs a soft elastic body made of silicone rubber that serves as both the structural framework and the actuating element. The spiral pneumatic channel is embedded within this flexible shell, allowing the soft material to deform and twist in response to pneumatic pressure while maintaining structural integrity. This approach enables complex mimetic motions without requiring additional rigid components or complex mechanisms.
Solution Approach 2:
The invention uses a spiral pneumatic channel that winds through the soft elastic body. When pneumatic pressure is applied, the channel expands and causes the entire gripper structure to twist and deform in a controlled manner. This pneumatic actuation mechanism provides simple yet effective control over complex motions, avoiding the need for motors, linkages, or other complex mechanical systems.
2Adaptability or versatility
If existing soft robotic grippers are designed for general applications, then adaptability is improved, but operation space requirement increases
Solution Approach 1:
The gripper features a spiral pneumatic channel that winds in a helical pattern through the soft elastic body. This curved, spiral geometry allows the gripper to compact its structure while maintaining the ability to expand and grasp objects of various sizes. The spiral configuration enables the gripper to access confined spaces and wrap around objects efficiently, reducing the required operation space compared to linear or rigid gripper designs.
3Device complexity
If no sensor is embedded in the soft robotic gripper, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The invention replaces traditional mechanical sensors with an optical sensing system based on fiber optic technology. A fiber optic sensor is embedded within the soft elastic body, utilizing optical principles to detect the twisting angle and deformation of the gripper. This substitution eliminates the need for complex mechanical linkages, gears, or contact-based sensors that would compromise the softness and flexibility of the gripper, while providing precise measurement capabilities.
Solution Approach 2:
The gripper integrates multiple materials with complementary properties: the soft elastic body made of silicone rubber provides flexibility and deformability, while the embedded fiber optic sensor material provides sensing capability. This composite structure allows the sensor to be seamlessly integrated into the soft material, maintaining the gripper's overall softness while enabling precise optical measurements of deformation and twisting angle.
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 gripper can securely grip objects as small as 1 mm in diameter and detect external perturbations, achieving high repeatability and accuracy with minimal operation space, thanks to the embedded sensor and optimized material properties.
Implementation Method 1
The embedded fiber optic sensor can be a high-birefringence (HB) fiber optic sensor
Implementation Method 2
pneumatic spiral channel twining around the elastic spine, the pneumatic channel formed in a soft gripping material surrounding the elastic spine
Data Source
AI summary
Various examples are provided related to pneumatic soft robotic spiral grippers. A fiber optic sensor can enable spiral-gripper sensing of, e.g., atwining angle and target cylinder diameter. In one example, a pneumatic soft robotic spiral gripper includes an elastic spine with an embedded fiber optic sensor and a pneumatic spiral channel twining around the elastic spine. The pneumatic spiral channel can be formed in a soft gripping material surrounding the elastic spine. In another example, a method fabrication of a pneumatic soft robotic spiral gripper includes providing a gripper mold with an outer mold wall and a spiral shaped rod positioned within the outer mold wall. An elastic spine can be inserted through the spiral shaped rod and the gripper mold filled with gripping material that can be cured to form a soft gripping material surrounding the elastic spine.