Cylindrical Flexible Body Bend Detection with Torsional Sheathing
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Solution Overview
Problem
Conventional cylindrical flexible body apparatuses, such as endoscopes, face challenges in accurately detecting and calculating the bend shape of flexible sections due to limitations in precision and susceptibility to twisting, which affects the reliability and accuracy of bend detection.
Innovation Solution
A shape measuring cylindrical flexible body apparatus incorporating a bend detection sensor with a curvature detection optical fiber, a light source unit, and a light detection unit, along with a cylindrical sheathing member that provides torsional rigidity and reduces friction, allowing for precise calculation of bend shapes by varying light characteristics based on curvature and direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a bend detection sensor with optical fiber is incorporated in the cylindrical flexible body, then bend shape detection capability is improved, but twisting occurs affecting measurement accuracy
Solution Approach 1:
A cylindrical sheathing member is introduced as an intermediary component between the optical fiber and the flexible body structure. This sheathing member provides torsional rigidity to prevent twisting of the optical fiber while maintaining the flexibility of the cylindrical body, thereby resolving the contradiction between bend detection capability and twisting prevention
Solution Approach 2:
The cylindrical sheathing member is constructed as a composite structure combining materials with different properties - an inner layer providing flexibility and an outer layer providing torsional rigidity. This composite construction allows the simultaneous achievement of flexibility for bend detection and torsional resistance to prevent twisting
2Ease of operation
If the cylindrical flexible body is made more flexible to improve insertion capability, then ease of insertion is improved, but torsional rigidity decreases causing twisting
Solution Approach 1:
The cylindrical flexible body is segmented into multiple functional layers with distinct roles: an inner flexible layer for ease of insertion and movement, and an outer sheathing layer for providing torsional rigidity. This segmentation allows each layer to optimize its specific function without compromising the other
Solution Approach 2:
Different regions of the cylindrical structure are assigned different mechanical properties - the inner core region is designed for flexibility to facilitate insertion and navigation, while the outer sheathing region is designed for torsional rigidity to prevent twisting of the optical fiber
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 apparatus achieves higher precision in calculating bend shapes and reduces the occurrence of twisting, thereby enhancing the accuracy and reliability of bend detection in cylindrical flexible bodies.
Implementation Method 1
an optical fiber extending along a longitudinal direction of the cylindrical flexible body and configured to guide the detection light radiated from the light source unit
Implementation Method 2
at least one detection target provided in the optical fiber and configured to vary characteristics of the detection light in accordance with a curvature of the optical fiber
Data Source
AI summary
A shape measuring apparatus includes a cylindrical flexible body and a bend detection sensor. The sensor includes an optical fiber extending along the flexible body, a detection target to vary characteristics of detection light guided through the optical fiber in accordance with a curvature of the optical fiber, and a light detection unit to detect the detection light. The shape measuring apparatus also includes a shape calculating device to calculate a bend shape of the flexible body, based on the variation of the characteristics of the detection light, a cylindrical sheathing member sheathing a part of the optical fiber in the flexible body, and a hard distal member provided at a distal end of the flexible body and holding a distal end of the sheathing member.