Continuum Robot Control Device for Twist Compensation

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Solution Overview

Problem

Continuum robots experience a decrease in accuracy of drive control when twisted during insertion or extraction, particularly in narrow spaces like pipes or body cavities, due to a deviation in the correspondence between driving displacement of wires and orientation, which existing techniques do not adequately address.

Innovation Solution

A control apparatus and method for continuum robots that calculates and adjusts the driving displacement amounts of wires based on image information to maintain accurate orientation control, even when twisted, by using a kinematic model and torsional amount acquisition to set the driving displacement amounts of the wires, ensuring precise control and smooth movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the continuum robot is inserted into a narrow space such as a pipe or body cavity, then the robot can reach and operate in confined areas, but the robot may come into contact with the inner wall and become twisted, causing deviation in the correspondence relationship between wire driving displacement and robot orientation

Engineering Contradiction:
Improveability to operate in narrow spacesVSAvoidaccuracy of drive control
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent employs feedback mechanisms by acquiring image information from the inspection target and comparing it with stored reference images to detect the robot's orientation. This feedback loop allows the system to monitor and correct deviations caused by twisting, maintaining accurate control despite the robot's flexible structure and narrow space operations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces direct mechanical control of wire displacement with image-based orientation detection and calculation. Instead of relying solely on mechanical feedback from wire tension or position sensors, the system uses visual information processing to determine robot orientation and calculate corresponding wire driving amounts, substituting mechanical measurement with optical sensing and computational analysis

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If the correspondence relationship between wire driving displacement and robot orientation deviates from design values due to twisting, then control accuracy decreases, but maintaining the original control method would require complex compensation mechanisms

Engineering Contradiction:
Improvesimplicity of control methodVSAvoidorientation control accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces image information as an intermediary element between the robot's physical state and the control system. By capturing images from the inspection target and comparing them with reference images, the system obtains orientation information without direct mechanical measurement, serving as a mediator that bridges the gap between robot position and control commands

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the control parameter from direct wire displacement control to image-based orientation control. By storing reference images at known orientations and comparing real-time images against these references, the system transforms the control parameter from mechanical displacement to visual orientation data, allowing dynamic adjustment of wire driving amounts based on detected orientation

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3714763B1Control device for continuum robot, control method for same, and program
Publication Date: 2024.08.07 CANON KK
  • EP3714763B1 patent drawingFigure 1
  • EP3714763B1 patent drawingFigure 2
  • EP3714763B1 patent drawingFigure 3

AI summary

A control apparatus 200 for a continuum robot 100 including a curved portion that is curved by driving a wire with a driving mechanism includes an image DB/torsional-amount acquisition unit 210 that obtains the torsional amount of the continuum robot 100 and a kinematic operation unit 230 that sets the driving displacement amount of the wire driven by the driving mechanism on the basis of the torsional amount obtained by the image DB/torsional-amount acquisition unit 210.