Antenna Pointing System With Flexible Universal Joint
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Solution Overview
Problem
Existing steerable antenna systems for spacecraft are hindered by high profile, heavy mass, structural inefficiency, high cost, low accuracy, low resolution, low reliability, and reduced RF performance, particularly when requiring small scan angles.
Innovation Solution
A pointing system utilizing two rotary actuators with connecting rods and a flexible universal joint mounting structure, allowing for lower profile, reduced mass, and improved RF performance, eliminating the need for hold-down mechanisms and moving harnesses, with the ability to select a stowed position at launch and providing higher accuracy and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two rotary actuators are assembled in a sequential chain holding the payload, then the antenna can achieve steerable tracking capability, but the system becomes heavy and has high profile
Solution Approach 1:
The system divides the payload into multiple segments (antenna reflector, hub, connecting rods) that can be independently positioned and secured. The payload is segmented into components that can be stowed separately during launch and deployed independently in orbit, reducing the need for heavy structural support throughout the entire assembly.
Solution Approach 2:
The patent employs dynamic positioning mechanisms where the payload can be moved to different stowed positions along the boom structure. The system transitions from a static heavy support structure to a dynamic configuration where components can be repositioned and secured at optimal locations, reducing overall system mass while maintaining tracking capability.
2Reliability
If two rotary actuators are assembled in a sequential chain holding the payload, then the antenna can achieve steerable tracking capability, but the structural efficiency is reduced
Solution Approach 1:
The patent transitions from a sequential chain arrangement (one-dimensional linkage) to a distributed spatial configuration where actuators and payload components are positioned at different locations along the boom structure. This dimensional redistribution allows for more efficient load paths and better structural utilization, improving strength-to-weight ratio while maintaining tracking capability.
3Reliability
If hold down and release mechanisms are used, then the payload can be secured during launch, but the device complexity increases
Solution Approach 1:
The payload positioning system is designed to be self-securing through gravity and structural constraints. When the payload is positioned at the desired stowed location along the boom, its own weight and the structural geometry naturally secure it in place, eliminating the need for additional active hold-down mechanisms. The system uses passive mechanical constraints rather than active locking mechanisms.
4Device complexity
If fixed predetermined stowed position is required for launch, then the structure can be simplified, but the adaptability is reduced
Solution Approach 1:
The system provides dynamic adaptability by allowing the payload to be positioned at multiple discrete stowed locations along the boom structure. The actuators can place the payload at different positions depending on mission requirements, launch vehicle constraints, or operational needs. This dynamic reconfigurability is achieved through a relatively simple mechanism that allows incremental positioning along the boom length.
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 a lower profile, reduced mass, higher accuracy, and improved RF performance while eliminating the need for hold-down mechanisms and moving harnesses, enabling last-minute stowed position selection and enhanced reliability.
Implementation Method 1
a flexible mounting structure for movably attaching the payload to the mounting surface. Conveniently, the flexible mounting structure is a universal joint
Data Source
AI summary
An antenna pointing system for selectively moving a payload relative to a mounting surface includes at least one rotary actuator having a moving part movable relative to a fixed part mounted on the surface. A connecting rod movably connects to the moving part and to the payload. A flexible mounting structure movably attaches the payload to the mounting surface.