Stereo Vision Calibration for Power Tool Tracking
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Solution Overview
Problem
Current vision systems for power tools face challenges in accurately calibrating and tracking movements in dynamic assembly line environments, particularly when operating on moving targets with complex access requirements, leading to potential errors in tightening operations.
Innovation Solution
A vision system that integrates with power tools, utilizing a reference plate with multiple LEDs or reflective spheres for 3D tracking and calibration, allowing for automated calibration during operation using the infrared spectrum, enabling precise location and orientation determination of the power tool, and employing a motion monitor for learning proper tool movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a vision system is used to track power tool movements in dynamic assembly line environments, then measurement precision is improved, but device complexity increases due to the moving target and multiple access directions
Solution Approach 1:
A reference plate with known geometry and detectable features (LEDs or reflective spheres) is introduced as an intermediary between the vision system and the power tool. The reference plate provides a stable coordinate system that the vision system can track, simplifying the complexity of directly tracking the moving power tool while maintaining measurement precision.
Solution Approach 2:
The reference plate creates a virtual copy or representation of the tool's position and orientation through its detectable features. Instead of directly measuring the complex power tool movements, the system tracks the simpler reference plate features and mathematically relates them to tool position, reducing system complexity.
2Measurement precision
If manual calibration is performed for the vision system, then measurement precision can be achieved, but loss of time occurs due to manual intervention requirements
Solution Approach 1:
The vision system performs automatic calibration using the reference plate features without requiring manual intervention. The system automatically detects the reference plate, calculates transformation parameters, and updates its coordinate system, eliminating time-consuming manual calibration while maintaining precision through automated image processing algorithms.
Solution Approach 2:
The reference plate is pre-configured with known geometric features and detectable markers (LEDs or reflective spheres) that enable the vision system to automatically perform calibration. The pre-established reference geometry allows the system to quickly compute transformation parameters without manual measurement, reducing calibration time while ensuring accuracy.
3Productivity
If the vision system operates in real-time during power tool movement, then productivity is improved, but measurement precision may deteriorate due to motion blur and dynamic conditions
Solution Approach 1:
The vision system captures images at regular intervals during power tool movement, creating a sequence of periodic measurements. This periodic sampling allows the system to track motion over time while maintaining precision through frame-by-frame analysis, balancing real-time productivity with accurate measurement of dynamic positions.
Solution Approach 2:
The reference plate with high-contrast detectable features (LEDs or reflective spheres) is prepared in advance to provide clear, easily distinguishable markers even during motion. This preliminary configuration ensures that the vision system can accurately detect and track features in real-time images despite motion blur, maintaining measurement precision during productive operation.
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 accurate and efficient tracking and calibration of power tools in real-time, reducing errors in assembly operations by providing precise location and orientation data, and ensuring correct torque and sequence adherence during tightening processes.
Implementation Method 1
A vision system that integrates with power tools, utilizing a reference plate with multiple LEDs or reflective spheres for 3D tracking and calibration
Implementation Method 2
allowing for automated calibration during operation using the infrared spectrum
Data Source
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AI summary
A vision system may include a first camera and a second camera mounted for stereoscopic monitoring of a work environment, a support platform for support of a workpiece in the work environment, a first reference plate operably coupled to the support platform to provide a first frame of reference for three dimensional location of objects in the work environment, a power tool operable in the work environment under control of a tool controller, and a motion monitor operably coupled to the first and second cameras to determine location of the tool in the work environment based on a comparison of a reference point on the tool to a position of reference points on the reference plate. A perspective view of the support platform by the first and second cameras may be changeable, and the system may further include a second reference plate to define a second frame of reference for three dimensional location of objects responsive to the perspective view of the support platform being changed.