Bendable Instrument Shape Determination via Control Element Slack Removal
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Solution Overview
Problem
Current techniques lack effective methods for accurately determining the shape of bendable instruments, such as catheters and endoscopes, which is crucial for precise maneuvering during surgical or exploratory procedures.
Innovation Solution
A system that involves moving and measuring the amounts of control elements without bending the instrument, using a method that includes removing slack from the control elements and employing sensors to determine the instrument's shape through calculated position deltas and kinematic relationships, allowing for precise shape determination independent of the force used and tortuosity of the control wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If control elements are moved to determine instrument shape, then shape information is obtained, but slack in control elements causes measurement inaccuracies
Solution Approach 1:
The system performs preliminary slack removal from control elements before shape determination measurements are taken. A pre-shaping command is sent to actuators to tension the control elements, eliminating slack that would otherwise cause measurement errors. This preliminary action ensures that subsequent shape measurements are accurate and reliable.
Solution Approach 2:
The system uses feedback from force sensors to monitor tension in control elements during measurement. The feedback mechanism detects when slack has been removed and when proper tension is achieved, allowing the system to confirm measurement validity and adjust if necessary.
2Measurement precision
If force is applied to remove slack from control elements, then measurement accuracy improves, but instrument position may change
Solution Approach 1:
The system applies force locally to specific control elements that require slack removal, rather than applying force to the entire instrument. By targeting only the necessary control elements and applying minimal necessary force, the system removes slack without causing unwanted instrument position changes.
Solution Approach 2:
The system carefully controls the parameters of force application, using force limits and controlled duration to remove slack while preventing excessive force that would move the instrument. The parameters are adjusted based on the specific measurement requirements and control element characteristics.
3Measurement precision
If multiple control elements are measured simultaneously, then shape determination is more accurate, but measurement complexity increases
Solution Approach 1:
The system segments the measurement process into distinct phases: slack removal for each control element, followed by measurement of that element. By breaking down the simultaneous measurement into sequential segments with proper timing, the system maintains measurement accuracy while managing complexity through structured organization.
Solution Approach 2:
The system uses a universal measurement approach where the same actuators and sensors serve dual functions: they both remove slack and perform measurements. This multi-functionality reduces the need for separate dedicated components, thereby reducing overall system complexity while maintaining the capability to measure multiple control elements.
Data Source
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AI summary
Embodiments of the invention relate to systems and methods for positioning a bendable instrument by moving at least two control elements first and second amounts to bend the instrument to a position; measuring the first and second amounts; and determining the position, shape or configuration of the instrument from the first and second amounts.