Compact Gimbal Nested Axis Laser Beam Stabilization
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Solution Overview
Problem
Current small gimbal systems with a diameter of less than 5 inches fail to meet the high pointing accuracy requirements for precision laser marker/designator applications, particularly in UAVs, due to inadequate stabilization and thermal management, leading to jitter and pointing errors.
Innovation Solution
A compact 2-axis gimbal system with additional nested axis subassemblies, incorporating a fast-steering mirror and a Coudé path for the laser beam, which enhances disturbance rejection and thermal management, and utilizes MEMS gyro and beam stabilization circuitry to maintain precise laser beam stabilization and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a two-axis el-over-az gimbal system is used with a diameter of less than 5 inches, then the weight is reduced and the size is compact, but the pointing accuracy and stabilization performance deteriorate and cannot meet the requirements for laser marker/designator applications
Solution Approach 1:
The patent implements a nested axis subassembly where a third axis (stabilization axis) is nested within the existing two-axis el-over-az gimbal structure. This allows the compact two-axis design to be enhanced with additional stabilization capability without proportionally increasing size or weight, achieving 25 μrad RMS laser spot stability through the nested corrective mechanism
2Device complexity
If a two-axis el-over-az gimbal system is used, then the construction is simplified and weight is reduced, but the disturbance rejection capability and stabilization performance worsen
Solution Approach 1:
The patent segments the stabilization function into a separate nested axis subassembly that operates independently from the primary el-over-az positioning axes. This modular segmentation allows the main two-axis gimbal to remain simple while the nested segment provides specialized disturbance rejection, achieving high reliability without proportionally increasing overall complexity
3Volume of moving object
If a high power laser is packaged in a compact gimbal system, then the size is reduced, but thermal management becomes more difficult and pointing accuracy deteriorates due to thermal instability
Solution Approach 1:
The patent introduces thermal management intermediaries including heat sinks and thermally conductive materials between the high power laser and the gimbal structure. These intermediary thermal management components enable compact packaging while maintaining effective heat dissipation and thermal stability, preventing thermal-induced pointing errors
4Measurement precision
If additional nested axis subassemblies are added to improve stabilization, then pointing accuracy is improved, but weight and size increase
Solution Approach 1:
The patent places the third stabilization axis nested within the existing two-axis gimbal structure, allowing the additional stabilization mechanism to share space with the primary axes. This nesting approach achieves 25 μrad RMS laser spot stabilization while minimizing the weight and volume increase that would result from adding a completely separate stabilization subsystem
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 provides improved pointing accuracy and stabilization, enabling the gimbal system to maintain a 25 μrad RMS laser spot on a target, suitable for small UAVs, while reducing weight and size, and actively correcting misalignment and thermal errors.
Implementation Method 1
a fast-steering mirror and a Coudé path for the laser beam
Implementation Method 2
utilizes MEMS gyro and beam stabilization circuitry to maintain precise laser beam stabilization and alignment
Implementation Method 3
beam stabilization circuitry to maintain precise laser beam stabilization and alignment
Implementation Method 4
a Coudé path for the laser beam, which enhances disturbance rejection
Data Source
AI summary
A small form-factor gimbal system that provides for stabilization of payload assets in a manner that provides improved stabilization capability. Such a small form-factor gimbal system provides for precision payload asset steering functionality through integration of an inertially stabilized two-axis gimbal in combination with a beam stabilization mechanism (BSM). In a preferred embodiment, such a small form-factor gimbal system has a gimbal diameter of about 5″ or less and employs a laser assembly having a Coudé path arrangement in which the laser beam passes from the azimuth subassembly to the elevation subassembly along the elevation subassembly rotational axis.