Stacked Stewart Platform Assemblers for Precise In-Space Assembly
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Solution Overview
Problem
Current in-space assembly (iSA) concepts rely on complex deployment mechanisms and long-reach manipulators that are mission-specific and incapable of high-precision manipulation, leading to undesirable dynamic modes and requiring additional mass, which limits their effectiveness in assembling large space structures.
Innovation Solution
A modular and reconfigurable manipulation system architecture using stacked Stewart platforms with control algorithms that enable high-accuracy and high-precision autonomous assembly, including fault detection and correction capabilities, allowing the system to adapt and complete tasks without human intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex deployment mechanisms and long-reach manipulators are used for in-space assembly, then the ability to assemble large space structures is improved, but the system mass and device complexity increase significantly
Solution Approach 1:
The system divides the assembly task into multiple components that can be manufactured separately and deployed independently. The space structure is segmented into modular units that are assembled in-orbit, avoiding the need for a single complex manipulator system. Each module can be handled by simpler, more manageable robotic systems.
Solution Approach 2:
The patent employs nested deployment mechanisms where compact structures are folded or nested within smaller launch vehicle constraints, then deployed to their full operational size in-orbit. This allows large structures to be transported and assembled without requiring proportionally large manipulators during the assembly process.
2Adaptability or versatility
If complex deployment mechanisms and long-reach manipulators are used for in-space assembly, then the ability to assemble large space structures is improved, but additional mass is required which creates undesirable dynamic modes
Solution Approach 1:
By segmenting the structure into deployable modules, the system eliminates the need for heavy long-reach manipulators. Each module can be positioned using lighter, more efficient mechanisms, significantly reducing the overall moving mass while maintaining the capability to assemble large structures.
Solution Approach 2:
The patent employs dynamic deployment mechanisms that transform compact configurations into expanded operational configurations. This allows the system to achieve large assembly capabilities without the permanent mass penalty of fixed long-reach manipulators, as the structure dynamically transitions between compact and expanded states.
3Adaptability or versatility
If stacked Stewart platforms are used for manipulation, then six degree-of-freedom movement is achieved, but accuracy and precision for the pose of the top plate deteriorate
Solution Approach 1:
The system incorporates feedback mechanisms including sensors and control systems that continuously monitor the position and orientation of each Stewart platform module. This feedback enables real-time correction of positioning errors, maintaining high accuracy and precision despite the complexity of stacked six-degree-of-freedom mechanisms.
Solution Approach 2:
The patent replaces purely mechanical positioning systems with hybrid systems that incorporate electronic sensors, actuators, and control algorithms. This substitution allows for more precise control and measurement of the top plate pose, overcoming the inherent accuracy limitations of mechanical stacked Stewart platforms alone.
Data Source
AI summary
Methods and systems to control stacked hexapod platforms for use as tools, which function with both high accuracy and high precision are provided. In some embodiments, the methods and systems include a convergence of modern control theory, and machine learning. Furthermore, some embodiments provide control algorithms to carry out autonomous in-space assembly operations using assemblers. Some embodiments provide methods and systems which combine long-reach low precision manipulators and smaller, high-precision assembler with interchangeable tools.