Variable Stiffness Robotic Gripper Using Layer Jamming
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Solution Overview
Problem
Conventional robotic grippers face challenges in grasping irregular and fragile objects due to their rigid nature, which can lead to damage and require complex hardware and software for precise control, while compliant grippers lack sufficient load capacity and precision.
Innovation Solution
The development of variable stiffness robotic grippers based on layer jamming technology, featuring a flexible backbone with interlocked jamming layers and a membrane bag, which can be stiffened by applying negative pressure to increase friction and load capacity, allowing for adaptable grasping of various objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid grippers are used, then load capacity and precision are improved, but adaptability and safety to environment deteriorate
Solution Approach 1:
The gripper employs variable stiffness joints that can dynamically transition between rigid and compliant states. This allows the system to adapt its mechanical properties in real-time, providing high load capacity when needed while maintaining adaptability for different object geometries, thus resolving the contradiction between strength and adaptability
Solution Approach 2:
The invention changes the stiffness parameter of the gripper joints on-demand. By adjusting the stiffness parameter, the system can optimize performance for specific tasks - maintaining high stiffness for precision and load-bearing, and reducing stiffness for adaptability and safety, thereby resolving the contradiction between these opposing requirements
2Adaptability or versatility
If compliant grippers are used, then adaptability and safety are improved, but load capacity and precision deteriorate
Solution Approach 1:
The variable stiffness joints enable the compliant gripper to dynamically increase stiffness when load capacity is required. This dynamic adjustment allows the system to maintain adaptability during approach and grasping, while providing sufficient strength and precision during manipulation, resolving the contradiction between adaptability and load capacity
3Measurement precision
If multi-finger rigid grippers are used, then precision and control are improved, but device complexity deteriorates
Solution Approach 1:
The variable stiffness joints serve multiple functions: they provide precision control, enable adaptability to different objects, and ensure safety. This multi-functionality reduces the need for separate components like force sensors and complex control systems, thereby reducing hardware complexity while maintaining or improving control precision
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 grippers achieve a significant 180-fold increase in stiffness and a 30-fold increase in load capacity, enabling safe and precise handling of irregular and fragile objects with improved adaptability and reduced complexity.
Implementation Method 1
which can be stiffened by applying negative pressure to increase friction and load capacity
Data Source
AI summary
A finger for a robotic gripper may include a flexible backbone, a plurality of jamming layers, and a membrane bag. The backbone may have a first side, a second side, a third side, and a fourth side. The backbone may include a flexible beam, and a plurality of branches attached to the flexible beam and spaced apart from one another. Each branch may include a first end surface extending along the first side, and a second end surface extending along the second side. The first end surfaces may collectively extend along a majority of the first side, and the second end surfaces may collectively extend along a majority of the second side. The jamming layers may be positioned along the third side or the fourth side. The membrane bag may be positioned over the jamming layers.