3D Eye-to-Hand Coordination for Robotic Positioning
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Solution Overview
Problem
Achieving high accuracy in 3D eye-to-hand coordination for robotic systems is challenging due to positioning and movement errors from robotic arms, measurement errors in 3D vision, and errors in calibration targets, which limit the operating accuracy of robotic systems, especially in six-axis robots.
Innovation Solution
A robotic system that uses a machine-vision module with cameras and structured-light projectors to capture images, generate 3D point clouds, and compare surflet pairs with CAD models, while a robotic controller moves the end-effector in small steps based on visual feedback to improve positioning accuracy, and a coordinate-transformation module transforms poses from camera-centered to robot-centered coordinates using a transformation matrix derived during calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the robotic arm moves the component in large steps to reduce movement time, then productivity is improved, but positioning accuracy deteriorates due to accumulation of errors in transformation matrix and 3D vision measurement
Solution Approach 1:
The patent divides the movement from initial pose to target pose into multiple small steps, where each step's displacement is less than or equal to a predetermined maximum displacement value. This segmentation allows the system to maintain high positioning accuracy at each step while still achieving the overall movement goal, resolving the contradiction between movement speed and positioning accuracy by making many small precise movements rather than fewer large imprecise movements
Solution Approach 2:
The patent dynamically adjusts the movement strategy by determining the next step based on the current pose and target pose, with each step size adaptively constrained by the maximum displacement value. This dynamic approach allows the system to optimize the balance between productivity and precision during the movement process, rather than using a fixed step size
2Adaptability or versatility
If the robotic system uses 3D vision and transformation matrices to achieve flexible positioning, then adaptability is improved, but measurement precision deteriorates due to errors in 3D vision, transformation matrix, and calibration target
Solution Approach 1:
The patent implements feedback by determining the current pose of the component at each step using the 3D vision system, then using this feedback information to determine the next step. This closed-loop feedback mechanism allows the system to compensate for measurement errors and transformation matrix inaccuracies in real-time, maintaining adaptability while improving actual positioning precision through continuous correction
Solution Approach 2:
The patent performs preliminary calibration to obtain the transformation matrix before actual operation, and uses this pre-established transformation relationship to guide subsequent movements. This preliminary action establishes a reference framework that enables flexible positioning while the system later compensates for its inherent errors through feedback during operation
3Adaptability or versatility
If the robotic arm operates across the entire working space to maximize coverage, then adaptability is improved, but positioning accuracy deteriorates due to significant variation in accuracy across different workspace regions
Solution Approach 1:
The patent dynamically adjusts the step size and movement strategy based on the current position and target position within the workspace. By constraining each step to be within the maximum displacement value and determining next steps adaptively, the system maintains consistent positioning accuracy across the entire workspace coverage, resolving the issue of accuracy variation in different regions
Data Source
AI summary
One embodiment can provide a robotic system. The system can include a machine-vision module, a robotic arm comprising an end-effector, and a robotic controller configured to control movements of the robotic arm to move a component held by the end-effector from an initial pose to a target pose. While controlling the movements of the robotic arm, the robotic controller can be configured to move the component in a plurality of steps. Displacement of the component in each step is less than or equal to a predetermined maximum displacement value.