Segmented Sub-Reflector Structure for Two-Stage Pose Adjustment
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Solution Overview
Problem
Dual-offset antennas face challenges in precise adjustment of sub-reflectors due to low processing precision, lack of precision adjustment points, and structural instability, leading to reduced antenna efficiency and reliability, especially in large-scale projects like the Square Kilometre Array (SKA) radio telescope.
Innovation Solution
A uniformly-partitioned high-precision sub-reflector device with a two-stage position and pose adjustment function, utilizing a multi-rod parallel mechanism with a single-layer space frame backup structure and panel precise adjustment device, enabling six-degree-of-freedom adjustment and redundant design to enhance stiffness and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an integral sub-reflector made of composite material is used, then manufacturing procedures are simplified, but processing precision decreases due to internal stress and uneven shrinkage
Solution Approach 1:
The sub-reflector is divided into multiple panels instead of using a single integral structure. Each panel can be manufactured separately with controlled precision, avoiding the internal stress and uneven shrinkage problems of large integral composite structures. The panels are then assembled to form the complete sub-reflector surface.
2Ease of manufacture
If an integral sub-reflector structure is used, then manufacturing is simplified, but structural stability decreases due to few supporting points causing deformation during elevation travel
Solution Approach 1:
The sub-reflector is segmented into multiple panels that are independently supported by the backup structure. This segmentation allows for more distributed supporting points across the sub-reflector surface, improving structural stability during elevation travel while maintaining manufacturing simplicity through modular construction.
3Device complexity
If traditional parallel mechanism with three supporting points is used, then structure is simplified, but local stiffness decreases at connection positions of large aperture sub-reflector
Solution Approach 1:
The connection between the sub-reflector and backup structure is segmented into multiple panel-level connections rather than three global connections. This increases the number of supporting points and distributes the load, improving local stiffness at connection positions while keeping each individual connection relatively simple.
Solution Approach 2:
The support structure transitions from a two-dimensional plane (three points on a plane) to a three-dimensional spatial configuration with multiple panels distributed across the sub-reflector surface. This dimensional expansion provides better spatial distribution of supporting points, enhancing local stiffness without significantly increasing overall mechanism complexity.
4Device complexity
If sub-reflector lacks precision adjustment points, then structure is simpler, but position precision cannot be controlled resulting in reduced yield
Solution Approach 1:
Precision adjustment points and mechanisms are pre-installed on the sub-reflector panels during manufacturing. This preliminary action ensures that position precision can be controlled and adjusted after assembly, improving yield without requiring complex post-assembly adjustment systems.
5Ease of operation
If hexapod parallel mechanism with six driving systems is used, then six-degree-of-freedom adjustment is achieved, but reliability decreases when one driver or rod fails
Solution Approach 1:
The hexapod parallel mechanism is segmented into multiple independent driving systems, each controlling specific degrees of freedom. This segmentation allows the system to maintain functionality even when one driver or rod fails, as the remaining segments can continue to operate, thereby improving reliability while preserving six-degree-of-freedom adjustment capability.
Data Source
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AI summary
The present invention discloses a uniformly-partitioned high-precision sub-reflector device with a two-stage position and pose adjustment function, relating to technical fields of communication, measurement and control, radio astronomy etc. The sub-reflector device of the present invention comprises an adjustment device, a sub-reflector, a single-layer space frame backup structure and a panel precise adjustment device. The adjustment device adopts movable and fixed platforms as a multi-rod six-degree-of-freedom sub-reflector adjustment mechanism for a plane truss to realize a primary pose adjustment of the sub-reflector; the sub-reflector is composed of a polygonal panel and several sectorial panels which are uniformly partitioned; the ratio of the number of inner and outer sides of the single-layer space frame backup structure is 1: 2, so as to provide a structural support for the sub-reflector; and the panel precise adjustment device is used for achieving a secondary pose adjustment of the sub-reflector. This device not only realizes a two-stage position and pose adjustment of the sub-reflector, but also improves the integral stiffness and reduces the overall weight of the sub-reflector, while improving the installation and adjustment efficiency and the adjustment precision.