Primary Mirror Support Structure for Telescope Deformation Control
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Solution Overview
Problem
Large telescopes with segmented primary mirrors face self-weight deformation issues due to orientation changes, leading to curvature deformation and compromised mirror accuracy, especially when the elevation axis is positioned high, increasing the telescope's height and complexity.
Innovation Solution
A primary mirror support structure comprising arc-shaped members, a truss structure frame, and multiple support members that connect to the circumference of the primary mirror, distributing the weight to prevent curvature deformation by rotating the primary mirror about the elevation axis and supporting it through a double truss structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the primary mirror support structure has a large height to reduce self-weight deformation, then the mirror accuracy is improved, but the telescope height increases and the dome size becomes larger
Solution Approach 1:
The patent employs arc-shaped members instead of straight support structures. These curved members provide structural rigidity while maintaining a compact footprint, allowing the support structure to resist deformation without increasing the telescope's height. The curvature geometry distributes loads more efficiently compared to linear arrangements.
Solution Approach 2:
The patent transitions from a vertical height-based support solution to a horizontal spread-based solution using arc-shaped members that extend laterally. By utilizing the horizontal dimension more effectively, the structure achieves the necessary stiffness without proportionally increasing the vertical height, thus reducing the dome size requirement.
2Length of moving object
If the EL rotation structure is provided on either side of the primary mirror support structure, then the telescope height is reduced, but the primary mirror surface sags significantly in the center due to self-weight deformation
Solution Approach 1:
The patent divides the support structure into multiple discrete support members distributed across the primary mirror surface. Instead of a few long support members that would sag, multiple shorter support members are arranged to provide distributed support, preventing central sagging while maintaining a compact overall structure.
Solution Approach 2:
The patent varies the distribution and configuration of support members based on local requirements. Support members are strategically positioned to provide enhanced support where needed (such as under the center of the mirror) while maintaining the compact horizontal footprint. The arc-shaped members are configured with specific curvature radii optimized for local structural performance.
3Manufacturing precision
If actuators are utilized to correct the deflected mirror surface, then the mirror accuracy is improved, but the correction is not perfect due to restriction on stroke
Solution Approach 1:
The patent implements preliminary anti-action by designing the support structure itself to prevent deformation before it occurs. The arc-shaped members and distributed support members are configured to maintain the primary mirror surface within acceptable tolerances under all operating conditions, reducing or eliminating the need for active actuator correction. This passive prevention approach avoids the limitations of actuator stroke.
Data Source
AI summary
The primary mirror support structure comprises an EL rotation structure including two arc-shaped members, a truss structure frame, and a primary mirror support structure. The arc-shaped members face each other via the EL axis and supporting the primary mirror, each of which rotates about the EL axis along an outer surface so as to rotate the primary mirror about the EL axis. The truss structure frame is connected to either one of the arc-shaped members at the ends. The primary mirror support structure includes multiple support members connecting multiple points on the circumference of the primary mirror provided above the truss structure frame to the truss structure frame. At least the support members nearest to the arc-shaped members are connected to the truss structure frame at parts different from the ends at which the truss structure frame is connected to the arc-shaped members.