Cylindrical Actuator Flexure Guidance Parasitic Error Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cylindrical actuators with flexure-based mechanisms face challenges in achieving precise linear movement along a specific axis while minimizing parasitic errors such as out-of-plane motion and tilting, which is crucial for applications like autofocus camera modules and endoscopic instruments.
Innovation Solution
A cylindrical actuator subassembly with a flexure-based linear guidance mechanism using a combination of axial and transverse flexures, forming a virtual parallelogram with flexible corners, to restrict movement to a single axis and minimize secondary motion, achieved through a system of ring-shaped levers and flexures with strategically angled connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a lever mechanism is used to amplify movement, then the driving force is amplified, but parasitic errors such as out-of-plane motion and tilting increase
Solution Approach 1:
The patent employs flexures (flexible elements) instead of rigid links in the lever mechanism. These flexures can bend and deform elastically to accommodate the rotational movement while maintaining constraints that prevent parasitic errors. The flexible nature allows the mechanism to amplify force through lever action while the controlled flexibility prevents out-of-plane motion and tilting, thus resolving the contradiction between force amplification and precision maintenance.
2Manufacturing precision
If a guidance mechanism is added to limit transverse movement, then parasitic errors are minimized, but device complexity increases
Solution Approach 1:
The patent integrates the guidance function directly into the lever mechanism itself through the use of flexures. Rather than adding a separate guidance mechanism, the flexural elements are designed to inherently constrain movement to the desired linear path while allowing the necessary rotational amplification. This merging of amplification and guidance functions into a single integrated structure minimizes complexity while achieving precision.
3Manufacturing precision
If multiple separate actuator units are used for paired flexures, then linear displacement is achieved, but the device becomes bulky and complex
Solution Approach 1:
The patent segments the actuator into a modular cylindrical structure with a stack of alternating rigid and flexible elements. Each segment (rigid element followed by flexible element) contributes to the overall linear displacement function. This segmentation allows the complex displacement function to be distributed across multiple simple, repeating units, reducing overall complexity while maintaining precision. The modular nature also reduces the bulk compared to separate actuator units.
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 solution effectively limits transverse movement, ensuring high stiffness and load capacity while minimizing parasitic errors, thereby enhancing the precision and reliability of the actuator system for applications requiring linear displacement along a specific axis.
Implementation Method 1
at least four flexures (22, 27, 27'), each flexure being combined with another flexure and/or a lever to achieve a rotation point by forming an angle that ranges from 0° to 180°
Data Source
AI summary
A cylindrical actuator sub-assembly (100, 200, 300) comprising: an element (14, 24, 34) movable along a longitudinal axis (A), at least one actuating member and a guidance mechanism suitable for guiding the element, wherein aid guidance mechanism includes a first ring-shaped lever (11, 21, 31) and a second ring-shaped lever (11′, 21′, 31′) that are parallel to each other, at least two straight axial flexures (12, 12′; 22, 22′; 32, 32′), at least two flexures (16, 16′; 27, 27′; 36, 36′) and at least two bases (13, 13′; 23, 23′; 33, 33′), a first base carrying the movable element.