MEMS Bidirectional Actuator Using Elastic Return and Stop Constraint
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Solution Overview
Problem
Existing microelectromechanical systems (MEMS) for driving toothed wheels can only rotate in one direction due to insufficient elastic return forces, limiting their application in horology and other fields where bidirectional rotation is required, and using two separate driving devices increases mechanical bulk.
Innovation Solution
A microelectromechanical system with a single actuator that utilizes electrostatic and elastic forces to achieve bidirectional movement by incorporating a stop mechanism to maintain non-zero elastic return forces, allowing the drive tooth to move in both directions without increasing the system's bulk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single actuator with elastic return forces is used to drive the toothed wheel, then the device complexity is reduced, but the toothed wheel cannot rotate in the second rotation direction because the elastic return forces are insufficient
Solution Approach 1:
The patent introduces a stop mechanism that changes the positional parameter of the movable drive portion, preventing it from returning to the initial position where elastic forces would be nil. This parameter change maintains non-zero elastic return forces throughout the operation cycle, enabling bidirectional rotation capability while using a single actuator.
2Adaptability or versatility
If two distinct driving devices are provided to enable bidirectional rotation, then the rotation direction capability is improved, but the device bulk increases
Solution Approach 1:
The single actuator is designed to perform multiple functions: driving the toothed wheel in the first rotation direction using electrostatic forces, and driving it in the second rotation direction using elastic return forces. The stop mechanism enables this multi-functionality by ensuring elastic forces remain available for reverse direction driving, eliminating the need for a second dedicated actuator and thus reducing system bulk.
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 the toothed wheel to be driven in both rotation directions using a single actuator, reducing mechanical complexity and size while maintaining effective movement capabilities.
Implementation Method 1
the movable drive portion being adapted to be moved relative the fixed drive portion in a first direction, as a result of an electrostatic force generated by the application of a nonzero voltage between the fixed drive portion and the movable drive portion
Implementation Method 2
the movable drive portion being able to be moved relative to the fixed drive portion in a second direction, opposite to the first direction, when the applied voltage decreases as a result of an elastic return force generated by the suspension having been deformed elastically
Data Source
AI summary
The invention relates to a microelectromechanical system (10) comprising a drive module (200) comprising:a fixed drive portion (210),a movable drive portion (220), anda suspension (230),the movable drive portion (220) being able to be moved relative to the fixed drive portion (210) in a first direction (A), as a result of an electrostatic force, which causes an elastic deformation of the suspension (230), and the movable drive portion (220) being able to be moved relative to the fixed drive portion (210) in a second direction (B), opposite to the first direction (A), as a result of an elastic return force generated by the suspension (230),the actuator (11) also comprising a stop (24) limiting the movement of the first movable portion (220) in the second direction (B) so that the elastic force generated by the suspension (230) is not cancelled.