Force Estimation for Flexible Tubular Instruments via Deformation Modeling
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Solution Overview
Problem
Current force measurement systems for flexible tubular medical instruments, such as endoscopes, face challenges in accurately estimating forces applied at multiple positions along the instrument's length, particularly in deformable regions, which affects precise manipulation and minimizes the need for direct force sensors.
Innovation Solution
A force estimation system that calculates force information by measuring deformation states and mechanical characteristics at various longitudinal positions, using sensors to detect positions and shapes, and applying bending moment calculations to determine applied forces, allowing for real-time feedback and reduced sensor requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct force sensors are installed at multiple positions along the flexible tubular instrument, then force measurement accuracy is improved, but device complexity and instrument diameter increase
Solution Approach 1:
The patent replaces direct mechanical force sensors with an indirect measurement system that uses deformation sensors (such as strain gauges or optical fibers) to detect shape changes, combined with mechanical modeling to calculate forces. This substitution eliminates the need for complex force sensor arrays while maintaining measurement capability through computational methods.
Solution Approach 2:
The patent introduces deformation state measurements as an intermediary between the applied forces and the final force calculation. By measuring intermediate parameters (deformation, curvature, shape changes) and using mechanical models to bridge these measurements to force values, the system achieves force measurement without direct force sensors at each position.
2Measurement precision
If direct force sensors are installed at multiple positions along the flexible tubular instrument, then force measurement accuracy is improved, but instrument diameter increases
Solution Approach 1:
The patent replaces bulky direct force sensors with thin deformation sensors (such as optical fibers or strain gauges) that can be embedded within the instrument wall. This substitution significantly reduces the instrument diameter while maintaining the ability to measure forces through indirect deformation measurement and computational calculation.
Solution Approach 2:
The patent utilizes the flexible tubular structure itself and thin-film deformation sensors embedded within it to detect forces. The thin-film sensors conform to the instrument's flexible structure without adding significant diameter, enabling force measurement in a minimally invasive manner.
3Measurement precision
If deformation sensors are distributed along the flexible tubular portion, then force estimation accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the distributed deformation sensors serve multiple functions: they detect shape changes, provide positional information, and enable force calculation through mechanical modeling. This multi-functionality reduces the need for separate sensor systems and simplifies the overall device architecture while maintaining high measurement accuracy.
Solution Approach 2:
The patent enables the sensor system to automatically calculate forces from deformation measurements using pre-stored mechanical characteristics. The system self-calibrates and processes data without requiring complex external measurement equipment or manual calibration procedures, reducing operational complexity.
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
Enables accurate force estimation along flexible tubular instruments without the need for direct force sensors, enhancing precision and reducing instrument diameter, while facilitating real-time processing and improved operational safety.
Implementation Method 1
measuring or estimating coordinates and shapes at a plurality of longitudinal positions of the flexible tubular portion
Implementation Method 2
obtaining bending moments at the plurality of positions from the shapes obtained in the first step and a prestored bending stiffness at the plurality of positions
Data Source
AI summary
A force estimation system for calculating force information regarding forces applied to one or more positions of a flexible tubular portion having flexibility through an arithmetic operation, the force estimation system comprising: a processor configured to input the deformation state and the mechanical property at a plurality of longitudinal positions of the flexible tubular portion, and calculates the force information of the force applied to the individual positions of the flexible tubular portion based on the deformed state and the mechanical property.