Hyper Redundant Manipulator Error Compensation for Confined Space Inspection
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Solution Overview
Problem
Hyper redundant manipulators, such as 'snake arm' and 'elephant trunk' robots, face challenges in navigating confined spaces due to their coiled configuration, which causes positional and orientational errors when uncoiled for tasks like inspecting or repairing gas turbine engines, requiring significant external space for linear tracks or mobile platforms.
Innovation Solution
A method and apparatus for controlling hyper redundant manipulators that involve determining and compensating for positional and orientational errors caused by the coiled configuration by forming S-bend profiles, using a tip following algorithm, and storing coiled and uncoiling profiles to accurately position the manipulator along a trajectory, allowing for compact deployment and precise movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hyper redundant manipulator is mounted on a linear track or mobile platform to move the free end within the gas turbine engine, then the manipulator can perform inspection and repair activities, but it requires a significant amount of space outside the article which may be undesirable or prohibit use in certain instances
Solution Approach 1:
The manipulator sections are coiled within a compact base structure, nesting the long manipulator arms inside a small footprint base. This allows the manipulator to achieve long reach for inspection and repair tasks while maintaining a minimal external footprint when not in use, eliminating the need for large linear tracks or mobile platforms.
Solution Approach 2:
The manipulator transitions dynamically between coiled and uncoiled states. The base rotates to uncoil sections for task execution, then recoils them for compact storage. This dynamic configuration allows the system to adapt its physical footprint based on operational requirements, providing full functionality without requiring permanent large-scale support infrastructure.
2Area of stationary object
If the hyper redundant manipulator is coiled in a base to reduce space requirements, then the area occupied outside the article is minimized, but positional and orientational errors occur when uncoiled making it difficult to perform tasks accurately
Solution Approach 1:
The control system continuously monitors the actual position and orientation of manipulator sections during uncoiling and movement, comparing them against the desired trajectory. Error signals are generated and used to adjust actuator commands in real-time, compensating for deviations caused by the coiled configuration and ensuring accurate positioning for inspection and repair tasks.
Solution Approach 2:
The system pre-calculates and stores coiled and uncoiling profiles that account for expected positional and orientational errors. Before executing a task, the control system determines the appropriate profile based on the desired end position, allowing the manipulator to proactively compensate for coiling-induced errors and achieve accurate positioning without real-time trial and error.
3Area of stationary object
If the hyper redundant manipulator uses a coiled configuration to maintain compact form, then space constraints are overcome, but error compensation and trajectory alignment become complex requiring advanced control algorithms
Solution Approach 1:
Coiled and uncoiling profiles are pre-calculated and stored in memory before operation. These profiles contain predetermined section positions and orientations for various stages of deployment. During operation, the control system simply retrieves and executes the appropriate profile, dramatically simplifying real-time control while still achieving accurate trajectory following despite the complex coiled configuration.
Solution Approach 2:
The manipulator is divided into discrete sections that can be independently controlled. Each section has its own position and orientation parameters, allowing the control system to manage complexity by treating each segment separately rather than as a monolithic structure. This segmentation enables modular control strategies and simplifies the overall control algorithm.
Data Source
AI summary
Methods of controlling a hyper redundant manipulator, the hyper redundant manipulator including: a plurality of sections comprising a first free end section and a second end section; and a base arranged to receive the plurality of sections in a coiled configuration, the base being coupled to the second end section of the plurality of sections, the method comprising: receiving a trajectory for movement of the plurality of sections; determining an error in position and/or orientation relative to the trajectory for one or more sections of the plurality of sections, the error being caused at least in part by the coiled configuration; and controlling movement of the one or more sections using the determined error to compensate for the error in position and/or orientation of the one or more sections.