Layer Jamming Gripper With Rigid Inserts for Irregular Workpieces
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Solution Overview
Problem
Mechanized grippers face limitations in adapting to complex and irregularly shaped workpieces due to their inherent rigidity and inability to accommodate non-flat datum surfaces, especially with the increasing complexity of shapes from additive manufacturing processes.
Innovation Solution
A layer jamming structure with a membrane and overlapping material layers that transitions from a compliant to a rigid state using a pressure system, assisted by rigid features and blocks, to conform to and securely grip workpieces with complex geometries, providing datum fixturing surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a mechanized gripper uses rigid mechanical structures for gripping, then the structural strength and stability are improved, but the adaptability to complex and irregular workpiece shapes deteriorates
Solution Approach 1:
The gripper structure transitions from a static rigid state to a dynamic state that can adapt its shape. The membrane structure with internal pressure control allows the gripper to dynamically change its geometry to match complex workpiece surfaces, resolving the contradiction between structural strength and shape adaptability.
Solution Approach 2:
The physical state of the gripper structure is changed by modifying internal pressure parameters. By controlling the pressure within the membrane structure, the gripper can transition between compliant and rigid states, enabling both adaptability to complex shapes and sufficient gripping strength when needed.
2Manufacturing precision
If a mechanized gripper uses fixed geometry structures, then the manufacturing precision and rigidity are improved, but the ability to conform to complex workpiece geometries deteriorates
Solution Approach 1:
The gripper employs a membrane structure that acts as a flexible shell, allowing it to conform to complex workpiece geometries while maintaining structural integrity. This flexible membrane enables the gripper to adapt to irregular shapes without sacrificing the rigidity needed for precise gripping when activated.
Solution Approach 2:
The structure transitions from a compliant flexible state to a rigid locked state through controlled activation. This dynamic transformation allows the gripper to first conform to the workpiece geometry in a flexible state, then lock into a rigid state for secure holding, resolving the contradiction between conformability and rigidity.
3Adaptability or versatility
If a gripper structure is made compliant to accommodate complex shapes, then the adaptability to workpiece geometry is improved, but the structural stability and gripping force deteriorates
Solution Approach 1:
The structural stability is controlled by changing the internal pressure parameter of the membrane structure. When high gripping force and stability are needed, the pressure is increased to lock the structure into a rigid state, while lower pressure allows compliance for shape adaptation, thus resolving the contradiction between adaptability and stability.
Solution Approach 2:
The gripper structure dynamically transitions between compliant and rigid states based on operational requirements. This dynamic state change allows the structure to be compliant during approach and conforming, then become stable and rigid during gripping, resolving the contradiction between adaptability and structural stability.
4Ease of manufacture
If conventional planar gripping surfaces are used, then the ease of manufacture is improved, but the ability to grip complex shapes without datum surfaces deteriorates
Solution Approach 1:
The membrane structure serves as a flexible shell that can be manufactured with simple geometry but achieves complex conforming capability through pressure control. This approach maintains ease of manufacture while dramatically improving the ability to grip complex shapes without requiring complex pre-formed gripping surfaces.
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
Enables secure gripping and holding of complex, irregularly shaped workpieces by conforming to their geometry and presenting stable fixturing surfaces, expanding the scope of shapes that can be handled and improving adaptability beyond conventional mechanical limitations.
Implementation Method 1
A pressure system includes a pump coupled with the internal cavity. The pressure system, with operation of the pump, changes a pressure in the internal cavity to transform the layer jamming structure from the inactivated conformable state to an activated rigid state
Implementation Method 2
The rigid structures help conform the layer jamming structure to the workpiece during transformation to the activated rigid state
Data Source
AI summary
Systems and methods are provided for gripping of a workpiece with a layer jamming structure having rigid datum structures. A system includes a layer jamming structure configurable in an inactivated conformable state, with a membrane defining an internal cavity containing a number of overlapping material layers. The rigid structures engage the layer jamming structure. A pressure system includes a pump coupled with the internal cavity to change a pressure therein to transform the layer jamming structure from the inactivated conformable state to an activated rigid state disposed around the workpiece. The rigid structures help conform the layer jamming structure to the workpiece during transformation to the activated rigid state and to present datum fixturing surfaces in the activated rigid state.