Snake-Arm Robot Visual Feedback Control Without Joint Encoders
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Solution Overview
Problem
Conventional snake-arm robots lack closed-loop control due to the absence of rotary encoders, relying on human operators for control and requiring imperfect dynamics models, which introduces uncertainties in operation.
Innovation Solution
A method utilizing real-time image data from optical sensors and preliminary dynamics models to compute desired velocities and movement instructions for snake-arm robots, enabling automatic closed-loop control without the need for encoders, using an image Jacobian and incremental dynamics models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rotary encoders are installed on snake-arm robot joints to enable closed-loop control, then control precision and reliability are improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical encoders with an optical-based control system. A camera captures images of the environment, and image processing algorithms compute the robot's pose and joint angles. This substitution eliminates the need for mechanical encoders on each joint while achieving closed-loop control through visual feedback and computational methods.
Solution Approach 2:
The patent introduces an intermediary computational layer between the camera and the robot joints. Image processing algorithms and dynamics models serve as intermediaries that translate visual information into control commands, enabling closed-loop control without direct mechanical sensing at each joint.
2Device complexity
If human operators manually control snake-arm robots without encoders, then device complexity is reduced, but measurement precision and control accuracy deteriorate
Solution Approach 1:
The patent implements a feedback control system using visual information. The camera continuously captures images of the environment, image processing algorithms compute the robot's current pose, and this information feeds back to adjust control commands. This closed-loop feedback mechanism significantly improves control accuracy compared to open-loop manual control.
Solution Approach 2:
The patent replaces manual operator control with an automated visual feedback system. Instead of relying on human operators to estimate and control joint positions, the system uses camera images and computational algorithms to automatically determine and adjust the robot's pose, achieving higher precision.
3Device complexity
If imperfect dynamics models are used for open-loop control, then device complexity is reduced, but reliability and control performance worsen due to uncertainties
Solution Approach 1:
The patent uses visual feedback to compensate for imperfections in the dynamics model. By continuously measuring the robot's actual pose through image processing and comparing it with the desired pose, the system can correct for model inaccuracies and uncertainties, improving reliability without requiring a perfectly accurate dynamics model.
Solution Approach 2:
The patent introduces an intermediary visual measurement system that acts as a mediator between the imperfect dynamics model and the actual robot behavior. The camera-based pose estimation provides accurate real-time information that compensates for model deficiencies, enabling reliable control despite using simplified dynamics models.
Data Source
AI summary
The present disclosure is related to methods and systems for controlling a snake-arm robot. The method includes receiving real-time image data associated with an operating environment or a location of a workpiece from optical sensor(s) mounted on a robot head of the robot; receiving input data describing a desired pose of the robot head; computing and translating a desired displacement of the robot head; computing a position of each of the links of the snake-arm robot to follow motion of the robot head, a current position of each the links, and data required to move joints connecting the links to move the robot to the desired pose; generating movement instructions; and transmitting the movement instructions to a drive motor associated with an introduction device or controllers associated with servo-motors operably connected to joints connecting the links of the snake-arm causing the robot head to move to the desired pose.