Piezoelectric Manipulator for TEM Sample Holder Rotation
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Solution Overview
Problem
Existing manipulators for rotating and translating sample holders in precise applications like Scanning Probe Microscopes and Transmission Electron Microscopes have limited rotational stroke and are prone to slippage, requiring repositioning of driving surfaces, which restricts movement accuracy and fragility.
Innovation Solution
A manipulator design using linear piezoelectric actuators with driving surfaces that move in opposite directions to achieve over 360 degrees of rotation without repositioning, and a tapered cylinder form to reduce vibrational sensitivity, allowing for precise translation and rotation without slippage and maintaining sample holder accessibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the manipulator uses a limited number of actuators with fixed driving surfaces, then the device complexity is reduced, but the rotational stroke is very limited (less than +/- 1 degree)
Solution Approach 1:
The patent applies dynamics by making the driving surfaces movable relative to the actuators. The driving surfaces can slide along the actuators' travel path, allowing the contact points to be repositioned dynamically. This enables the manipulator to achieve large rotational strokes (>360 degrees) without increasing the number of actuators or complexifying the overall structure, as the same actuators can contact the sample holder at different positions during rotation.
2Reliability
If the manipulator operates with static friction to maintain driving surface position, then the driving surfaces remain on the same position on the sample holder, but the movement produces stick/slip effects and irregularity
Solution Approach 1:
The patent replaces the static friction-based mechanical contact system with a rolling contact system. The sample holder rolls over the driving surfaces during rotation and translation, eliminating stick/slip effects. This substitution of the contact mechanism maintains reliable positioning while achieving smooth, accurate movement without the irregularities caused by static friction.
3Device complexity
If the manipulator uses conventional actuators with fixed contact points, then the structure is simple, but the rotational stroke is limited and requires repositioning of driving surfaces
Solution Approach 1:
The patent introduces an additional degree of freedom by allowing the driving surfaces to move not only with the actuators but also independently along the actuator direction. This dimensional freedom enables the driving surfaces to traverse the entire circumference of the sample holder during rotation, achieving >360 degrees rotational stroke without requiring multiple actuators or complex repositioning mechanisms.
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 precise and reliable movement of sample holders with extended rotational range and reduced sensitivity to vibrations, ensuring accurate positioning in high-precision instruments like TEMs and SPMs without the need for lubricants or fragile components.
Implementation Method 1
two sets of three piezoelectric actuators, each actuator pointing inwards from the base
Data Source
AI summary
A manipulator for use in e.g. a Transmission Electron Microscope (TEM) is described, said manipulator capable of rotating and translating a sample holder (4). The manipulator clasps the round sample holder between two members (3A, 3B), said members mounted on actuators (2A, 2B). Moving the actuators in the same direction results in a translation of the sample holder, while moving the actuators in opposite directions results in a rotation of the sample holder.