MEMS Actuator Structure for Bidirectional Gear Rotation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing microelectromechanical systems (MEMS) are limited to driving a gear in only one direction of rotation, necessitating two separate drive devices to achieve bi-directional rotation, which increases the system's size.
Innovation Solution
A microelectromechanical system with a single actuator comprising a drive module, clutch module, and indexing module, utilizing electrostatic and elastic forces to achieve bi-directional rotation through a movable stop and locking mechanism, allowing independent control of tangential and radial movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate drive devices are used to drive the gear in both directions, then the gear can rotate in two opposite directions, but the system size increases
Solution Approach 1:
The single actuator is designed to perform multiple functions: it can drive the gear in both clockwise and counter-clockwise directions, and it can also engage and disengage from the gear. This is achieved through a movable stop mechanism that can be positioned to enable bidirectional rotation, eliminating the need for separate actuators for each function.
Solution Approach 2:
The stop mechanism is made movable rather than fixed, allowing it to be repositioned to control the actuator's range of motion in different directions. This dynamic adjustment enables the single actuator to achieve bidirectional rotation by changing the mechanical constraints on its movement, rather than requiring multiple fixed actuators.
2Ease of operation
If the elastic restoring force is used to rotate the gear in the opposite direction, then the actuator returns to initial position, but the elastic restoring force decreases as the module approaches initial position making it insufficient to move the gear a full step
Solution Approach 1:
The actuator is designed with preliminary action where the electrostatic force not only drives the gear forward but also pre-positions the actuator and engages the stop mechanism in advance. This preliminary engagement of the stop ensures that when the actuator returns, the elastic restoring force is maintained at sufficient levels throughout the entire return stroke, rather than decreasing to zero.
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 bi-directional rotation of a gear using a single actuator, reducing the system's footprint while maintaining control over both directions of rotation.
Implementation Method 1
a first elementary module for moving the drive tooth in a first direction (radial direction)
Implementation Method 2
a second elementary module for moving the tooth in a second direction (tangential direction) relative to the gear
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a microelectromechanical system (10), comprising a drive module (200) comprising: - a stationary drive part (210), - a movable drive part (220), and - a suspension (230), the movable drive part (220) being capable of being moved with respect to the stationary drive part (210) in a first direction (A) when exposed to an electrostatic force which causes an elastic deformation of the suspension (230), and the movable drive part (220) being capable of being moved with respect to the stationary drive part (210) in a second direction (B), opposite to the first direction (A), when exposed to an elastic return force generated by the suspension (230), the actuator (11) further comprising an abutment (240) which limits the movement of the first movable part (220) in the second direction (B) so that the elastic force generated by the suspension (230) is not cancelled out.