Optical Closed-Loop Control for Snake-Arm Robot Positioning
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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 the control process.
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 to translate visual feedback into motor control commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotary encoders are installed on the snake-arm robot body, then closed-loop control precision is improved, but device cost and complexity increase
Solution Approach 1:
The patent replaces the mechanical encoder system with an optical-based visual feedback system. Instead of using rotary encoders to directly measure joint positions, the system uses optical sensors (cameras) to capture images of the workspace and workpiece, then processes these images to determine robot pose and guide control decisions, thereby avoiding the need for expensive encoders while maintaining control capability
Solution Approach 2:
The patent introduces an image processing intermediary system that acts as a mediator between the optical sensors and the control system. The image processor extracts feature data from images and converts it into control-relevant information, serving as an intermediary that translates visual information into actionable control signals without requiring direct mechanical measurement devices
2Productivity
If human operators manually control the snake-arm robot, then operational flexibility is maintained, but productivity and response speed decrease
Solution Approach 1:
The patent implements a closed-loop feedback control system where optical sensors continuously capture images of the workspace, the image processor analyzes these images to determine the current robot pose and workpiece location, and this information is fed back to automatically adjust robot movements. This feedback mechanism enables automatic control while maintaining adaptability to changing conditions
Solution Approach 2:
The robot system performs self-guided operation by using its own optical sensors to observe the workspace and automatically adjust its movements based on image processing results. The system serves itself by extracting control information from visual feedback without requiring continuous human intervention, thereby increasing productivity and automation level
3Loss of information
If visual sensors are added to provide feedback, then control information is improved, but device cost and complexity increase
Solution Approach 1:
The patent makes the optical sensor system multi-functional by using the same cameras and image processing hardware for multiple purposes: determining robot pose, locating workpieces, guiding tool positioning, and providing operational feedback. This universal use of visual information reduces the need for separate specialized sensors for each function, thereby limiting the increase in device complexity while maximizing information utility
Data Source
AI summary
Methods and systems for controlling a snake-arm robot. In an embodiment, a server computer receives real-time image data associated with at least one of an operating environment and a location of a workpiece from an optical sensor mounted on a robot head of a snake-arm robot, and receives, input data describing a desired pose of the robot head from a user device. The server computer then computes a desired velocity of the robot head using an image Jacobian, translates the desired velocity of the robot head into incremental displacement data and rotation data within a control cycle, computes a position of each of a plurality of links comprising a snake-arm of the snake-arm robot to follow motion of the robot head, computes a current position of each of the plurality of links utilizing a forward dynamics model, and computes force and torque data required to move at least one of a plurality of joints connecting the links to move the snake-arm robot to the desired pose. The method also includes generating movement instructions based on the force and torque data, and transmitting the movement instructions to at least one of a drive motor associated with an introduction device and a plurality of 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.