Medical Manipulator Bending Control via Auxiliary Traction Mechanisms
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Solution Overview
Problem
Existing medical manipulators with gear mechanisms require significant external force to bend and maintain the shape of the inserted portion, and when a traction mechanism fails, the bending portion loses controllability, making it difficult to conform to body tissues and maintain a stable angle.
Innovation Solution
A manipulator design featuring a bending portion with main and auxiliary bending mechanisms, where the auxiliary mechanisms can take over in case of a traction mechanism failure, allowing for continued control of the bending angle and smooth extraction, without the need for a large-diameter clutch mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gear mechanism is employed to precisely control the bending angle, then the bending angle control precision is improved, but the device complexity increases due to the need for large-diameter clutch mechanisms and complex switching structures
Solution Approach 1:
The manipulator divides the bending control function into multiple independent bending mechanisms (first, second, third, and fourth bending mechanisms) arranged at different positions along the inserted portion. Each mechanism independently controls bending at its specific location, eliminating the need for a single complex clutch mechanism while maintaining precise angular control through distributed simple mechanisms
Solution Approach 2:
The patent transitions from a single-point bending control mechanism to a multi-point distributed bending control system. By arranging bending mechanisms at multiple positions (proximal and distal ends of different sections) and controlling them independently, the system achieves precise overall bending angle control without requiring large-diameter clutch components at any single location
2Adaptability or versatility
If a clutch mechanism is used to switch between rigid and flexible states, then the adaptability is improved, but the device complexity and diameter increase
Solution Approach 1:
The manipulator employs multiple independently controllable bending mechanisms that can be dynamically activated or deactivated based on operational requirements. By selectively controlling which bending mechanisms are engaged, the system achieves dynamic switching between rigid and flexible states without requiring physical clutch mechanisms, maintaining adaptability while reducing structural complexity and diameter
Solution Approach 2:
Each bending mechanism serves multiple functions: it can be independently activated or deactivated to provide both rigid structural support and flexible bending capability. The same bending mechanism structure provides both states through control switching, eliminating the need for separate clutch mechanisms and reducing overall device complexity
3Stability of the object's composition
If a large external force is applied to maintain bending shape stability, then the stability is improved, but the ease of operation deteriorates when traction mechanism failure occurs
Solution Approach 1:
The manipulator segments the bending control into multiple independent mechanisms distributed along its length. When one mechanism fails, the other segments remain functional and can be controlled to maintain overall bending shape stability. This segmentation allows continued operation and smooth extraction even after failure, as the remaining mechanisms can compensate and maintain structural integrity without requiring large external forces
4Length of moving object
If the manipulator maintains a small-diameter structure, then the ease of insertion is improved, but the ability to maintain stable bending angle against external force deteriorates
Solution Approach 1:
The manipulator uses multiple small-diameter bending mechanisms distributed along its length instead of a single large-diameter mechanism. Each individual mechanism maintains a small diameter for easy insertion, but collectively they provide sufficient force resistance through distributed positioning and independent control, allowing the manipulator to maintain stable bending angles against external forces while preserving easy insertability
Data Source
AI summary
A manipulator includes an elongated main unit, a bending portion, and a distal end portion that are disposed in this order from a basal end; a plurality of main bending mechanisms having main linear members that extend from the distal end portion to the main unit, main motive-power generating portions), and main motive-power transmitting portions that transmit motive powers generated by the main motive-power generating portions to the main linear members in the form of linear motions in the longitudinal direction; a plurality of auxiliary bending mechanisms that are provided so as to form pairs with the respective main bending mechanisms and parallel thereto and that exert a pressing force and a tensile force on the distal end portion; and switching portions that selectively actuate either the main bending mechanisms or the auxiliary bending mechanisms, which are paired.