Flexure Actuator for Precise Rotary-to-Linear Optical Positioning
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Solution Overview
Problem
Conventional actuators for optical systems, such as those used in telescopes, are complex and heavy due to numerous parts, and there is a need for more precise and easier-to-manufacture solutions that can achieve precise positioning of optical elements over large distances with small increments, such as microns or nanometers.
Innovation Solution
An actuator system featuring a flexure assembly with cross-blade and rotary flexures that convert rotational input into linear motion, utilizing a monolithic design with a stepper motor and harmonic drives to provide high axial and lateral stiffness, eliminating mechanical play and the need for lubricants, and allowing for precise positioning of optical elements like lenses and mirrors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional motor and screw designs are used, then precise positioning of optical elements can be achieved, but the system becomes complex and heavy due to large number of parts
Solution Approach 1:
The patent combines multiple functions into integrated components. The flexure assembly integrates positioning, guiding, and motion conversion functions into a single monolithic structure, eliminating the need for separate motors, screws, and support components. This merging reduces part count and system complexity while maintaining precise positioning capability through the elastic deformation characteristics of the flexure blades.
2Measurement precision
If conventional motor and screw designs are used, then precise positioning can be achieved, but weight increases due to large number of parts
Solution Approach 1:
The flexure assembly merges multiple components into a single monolithic structure made from one piece of material. This integration eliminates the weight of separate motors, screw mechanisms, and support structures, reducing overall actuator weight while maintaining precise positioning through controlled elastic deformation of the flexure blades.
Solution Approach 2:
The patent replaces traditional mechanical screw and motor components with a flexure-based elastic mechanism. This substitution eliminates heavy mechanical parts while achieving precise motion control through the elastic properties of the flexure assembly, significantly reducing actuator weight.
3Ease of manufacture
If flexure assembly with monolithic design is used, then device complexity is reduced and manufacturing is simplified, but achieving high axial and lateral stiffness becomes challenging
Solution Approach 1:
The flexure assembly employs blades with non-uniform cross-sections and varying thicknesses along their length. This local quality variation allows different regions of the same component to provide different mechanical properties - softer regions for flexibility and positioning, while thicker regions provide the necessary axial and lateral stiffness. The oblique angle orientation of blades further optimizes stiffness characteristics in specific directions.
4Reliability
If conventional mechanical components are used, then motion conversion can be achieved, but friction and wear components reduce reliability
Solution Approach 1:
The patent replaces traditional mechanical screw and gear components that generate friction and wear with a flexure-based elastic mechanism. The flexure assembly converts rotational motion to linear motion through controlled bending and twisting of elastic blades, eliminating sliding friction and mechanical wear, thereby significantly improving system reliability and eliminating the need for lubrication.
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 system achieves precise positioning with high axial and lateral stiffness, enabling large distance actuation with fine resolution, reducing mechanical complexity and increasing reliability by eliminating friction and wear components, and allowing for precise control of optical elements in optical systems.
Implementation Method 1
cross-blade flexures operatively connect the carriage to the rotary base, the cross-blade flexures including a plurality of blade flexures and being oriented at an oblique angle to the rotary base and to the axis of the actuator system
Implementation Method 2
The rotary flexure includes a cruciform set of axially extending blades connecting between the rotary base and the frame configured for rotational flexibility in axial twisting and rigidity against bending
Data Source
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AI summary
An actuator system (100) includes a frame (102) configured to remain stationary relative to a carriage (104) within the frame and connected to the frame by a flexure assembly (106) configured to constrain the carriage for only linear motion along an axis of the actuator system. A rotary base is configured to receive rotational input. Cross-blade flexures (108) operatively connect the carriage to the rotary base, the cross-blade flexures including a plurality of blade flexures and being oriented at an oblique angle to the rotary base and to the axis of the actuator system. A rotary flexure operatively connects the rotary base to the frame. The cross-blade flexures and the rotary flexure are configured to convert rotary motion of the rotary base into linear motion of the carriage and to maintain axial and lateral stiffness.