Shape Memory Polymer Adhesive Gripper for Reversible Pick-and-Place
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Solution Overview
Problem
Existing robotic grippers face limitations in effectively adhering to and releasing objects across diverse surfaces, including smooth, rough, dry, wet, and porous materials, with issues such as low adhesion strength, damage risk, and complex manufacturing.
Innovation Solution
A gripper utilizing a shape memory polymer (SMP) dry adhesive with a dual structure and a rigid backing layer, capable of transitioning between rubbery and glassy states for reversible adhesion, combined with a release mechanism for easy detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electrostatic grippers are used for quick pick-and-place, then response speed is improved, but adhesion strength becomes relatively low unless voltage is very high which may damage electronic parts
Solution Approach 1:
The patent applies parameter changes by utilizing temperature as a control parameter to switch the adhesive state of the SMP material. By heating above Tg, the material becomes rubbery and releaseable; by cooling below Tg, it becomes glassy and adhesive. This temperature-based parameter change enables both fast response and strong adhesion without the need for high voltages that could damage electronic components.
Solution Approach 2:
The patent exploits phase transitions of the shape memory polymer between rubbery and glassy states through temperature changes. The phase transition at the glass transition temperature (Tg) allows the material to switch between adhesive and non-adhesive states, enabling quick pick-and-place operations with strong adhesion when needed, without requiring damagingly high electrostatic voltages.
2Force
If vacuum grippers are used to lift heavy objects, then lifting capability is improved, but effectiveness is reduced in vacuum or with porous objects
Solution Approach 1:
The patent achieves universality by using a SMP-based adhesive mechanism that works effectively across diverse surface types including smooth, rough, dry, wet, and porous surfaces. The temperature-controlled adhesive state allows the same gripper to handle various object types without requiring different mechanisms for different environments, including vacuum conditions.
Solution Approach 2:
The patent employs composite material structures combining SMP adhesive layers with supporting substrates to create a gripper that achieves both strong adhesion and mechanical strength. The composite construction allows effective gripping of heavy objects in vacuum or with porous surfaces by combining the adhesive properties of SMP with the structural integrity of the substrate.
3Strength
If gecko grippers are used for dry surfaces, then adhesion is achieved, but adhesion strength is limited and manufacturing is complicated
Solution Approach 1:
The patent replaces the complex mechanical microstructure of gecko grippers with a temperature-controlled polymer adhesive system. Instead of relying on complicated micro-setae structures that are difficult to manufacture, the invention uses a SMP material that achieves adhesion through controllable phase transitions, significantly simplifying the manufacturing process while maintaining or improving adhesion strength.
Solution Approach 2:
The patent uses parameter changes in temperature to control the adhesive state of the SMP material, replacing the structural complexity of gecko grippers with a simple thermal control mechanism. This allows strong adhesion on dry surfaces through temperature-controlled polymer phase transitions rather than through complicated microstructural designs.
4Ease of operation
If finger or soft grippers are used, then simplicity or human-like performance is improved, but they require target objects with multiple surfaces with acceptable dimensions
Solution Approach 1:
The patent applies parameter changes in temperature to control the adhesive properties of the SMP material, enabling the gripper to adapt to various surface geometries. By switching between rubbery and glassy states, the material can conform to different surface shapes and sizes, overcoming the limitation of traditional grippers that require specific geometric features for gripping.
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 SMP gripper achieves strong, material-independent adhesion and release on various surfaces, including smooth and rough, dry and wet, with enhanced adhesion strength and reduced peeling force, suitable for pick-and-place operations.
Implementation Method 1
heating the SMP dry adhesive of the at least one foot above a glass transition temperature thereof, thereby transitioning the shape memory polymer to a rubbery state
Implementation Method 2
a SMP dry adhesive having a dual structure comprising a first shape memory polymer having a first stiffness and a second shape memory polymer having a second stiffness
Data Source
AI summary
An adhesive gripper for pick-and-place maneuvers comprises one or more legs, where each leg terminates in a foot rotatably connected to the respective leg. Each foot includes a SMP dry adhesive comprising a shape memory polymer, and a rigid backing layer attached to a back side of the SMP dry adhesive, such that a front side of the SMP dry adhesive is available for attachment and release of objects. The adhesive gripper further includes a handle portion connected to the one or more legs, a release mechanism comprising a release ring within the handle portion, and one or more releasing rods integrated with the one or more legs for release of an object onto a substrate.