Medical Manipulator Arm Alignment via Optical Locus Feedback
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Solution Overview
Problem
Medical manipulators face challenges in accurately initializing their arm portions within the body cavity, leading to potential misalignment and reduced intuitive operation due to manufacturing errors and image processing inaccuracies, which affects the precision and efficiency of medical procedures.
Innovation Solution
A medical manipulator system that includes a light irradiation section, imaging section, and initialization control unit to acquire and converge the locus of an optical image, allowing for precise alignment of the arm portion with the reference axial line through a series of control steps, including locus acquisition, convergence determination, and driving amount correction, even in the presence of redundant joints and offset amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manufacturing errors and image processing inaccuracies are present, then the arm portion may be misaligned, but the system can still achieve accurate alignment through locus convergence control
Solution Approach 1:
The system uses feedback control by continuously monitoring the locus of the optical image and adjusting the driving amount of bending joints based on the convergence determination amount calculation. The initialization control unit repeatedly performs locus acquisition and driving amount correction until the locus converges, ensuring accurate alignment despite manufacturing errors or image processing inaccuracies.
Solution Approach 2:
The system performs preliminary alignment actions by acquiring the locus of the optical image before final positioning. The initialization process includes preliminary steps of locus acquisition, convergence determination amount calculation, and driving amount correction to prepare the arm portion for accurate alignment before the actual medical procedure begins.
2Measurement precision
If an encoder is added for positioning, then positioning accuracy improves, but the joint configuration becomes more complex
Solution Approach 1:
The system replaces mechanical positioning systems (encoders) with an optical field-based positioning method. Instead of using mechanical encoders to detect joint positions, the system uses a light irradiation section to project optical fields and an imaging section to capture the locus of these fields, substituting mechanical measurement with optical measurement to simplify the joint configuration.
Solution Approach 2:
The system introduces an optical field as an intermediary between the arm portion and the positioning system. The light irradiation section projects optical fields that interact with the arm portion, and the imaging section captures the resulting locus, using the optical field as a mediator to achieve positioning without direct mechanical sensors on the joints.
3Productivity
If the arm portion is misaligned, then procedural efficiency decreases, but the initialization control ensures accurate alignment
Solution Approach 1:
The system performs preliminary alignment actions through the initialization control unit that acquires the locus of the optical image and corrects driving amounts before the actual medical procedure begins. This preliminary alignment ensures that the arm portion is properly aligned with the reference axial line, preventing misalignment during the procedure and maintaining high procedural efficiency.
Solution Approach 2:
The system performs self-alignment through the initialization process where the arm portion automatically adjusts its position based on the locus convergence feedback. The initialization control unit autonomously calculates the convergence determination amount and corrects driving amounts without external intervention, enabling the system to self-correct alignment issues and ensure procedural efficiency.
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 intuitive and precise operation of the medical manipulator by ensuring the arm portion is accurately aligned with the reference axial line, improving procedural efficiency and reducing the risk of misalignment, even without an encoder for positioning, thus simplifying the joint configuration.
Implementation Method 1
a light irradiation section irradiating a luminous flux having an optical axis parallel to an axial line of the arm from an irradiation port disposed at an arm
Implementation Method 2
an imaging section provided at the distal end part of the insertion portion or the support portion and images a locus of an optical image based on the luminous flux
Data Source
AI summary
A medical manipulator includes an insertion portion, an arm portion, a light irradiation section irradiating a luminous flux having an optical axis parallel to an arm axial line, an imaging section imaging a locus of an optical image, a rotational movement portion rotating the arm portion around a reference axial line, and an initialization control unit performing initialization control to aligning the arm portion with the reference axial line, in which the initialization control unit includes: a locus acquisition control section controlling the light irradiation section, the rotational movement portion, and the imaging section to acquire a locus of the luminous flux, a convergence determination section computing a diameter of the locus and determines whether or not the diameter of the locus has converged, a driving amount correction section obtaining a driving amount of the first redundant joint and performs driving, and a convergence operation control section.