Digital Projection System for Truss Assembly Alignment
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Solution Overview
Problem
Existing truss-layout systems face issues with flicker and eye strain due to over-bright laser spots, and have limited calibration precision due to a limited number of reflective fiducial features, making it difficult to achieve accurate and efficient assembly.
Innovation Solution
A digital projection system that uses calibrated light projection to guide assembly, identifies multiple witness points in 3D space without additional fiducial marks, and adjusts images dynamically across multiple projectors to ensure accurate alignment and calibration, while providing real-time feedback and instructions to operators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If laser imaging systems are used for truss assembly guidance, then assembly alignment can be achieved, but eye strain and flicker occur due to over-bright laser spots
Solution Approach 1:
The patent removes the harmful laser component from the projection system while retaining the useful image projection function. Digital projectors replace laser imaging systems, eliminating over-bright spots and flicker that cause eye strain, while still providing accurate assembly guidance through projected images
Solution Approach 2:
The patent uses standard digital projectors instead of specialized laser imaging systems. These commercial off-the-shelf projectors are less expensive, more reliable, and eliminate the harmful effects of laser radiation while providing sufficient precision for truss assembly alignment
2Ease of manufacture
If a limited number of reflective fiducial features are used for calibration, then calibration can be performed, but calibration precision is limited
Solution Approach 1:
The patent divides the calibration process into multiple measurement points distributed across the work surface. By using numerous witness points instead of few fiducial features, the system achieves higher calibration precision through statistical averaging and better spatial coverage
Solution Approach 2:
The patent uses digital copies of calibration data stored in memory. The controller stores coordinates of multiple witness points and uses this digital information to calculate transformation parameters, replacing the need for physical fiducial features and enabling more precise calibration
3Area of stationary object
If multiple projectors are used to cover large assembly areas, then coverage is improved, but image alignment and calibration across projectors becomes complex
Solution Approach 1:
The patent merges multiple projector images into a unified coordinate system. The controller calculates transformation parameters that align all projector images with the work surface coordinate system, enabling seamless multi-projector operation without manual alignment complexity
Solution Approach 2:
The patent implements a feedback-based calibration process. The controller measures actual positions of witness points using cameras, compares them with expected positions, and adjusts transformation parameters accordingly. This closed-loop approach automatically aligns multiple projectors without manual intervention
Data Source
AI summary
A method and apparatus for assembling components of a workpiece. Some embodiments include a work surface; a first digital projector that projects an image of at least some features of the workpiece onto the work surface, wherein the image includes a plurality of line indicators that have visually discernible different markings such as colors or line types; a camera that obtains input images of the work surface and the components of the workpiece; and a first controller configured to receive the input images from the camera and to control the first digital projector to project the first output digital image on the work surface for assembly of the components to form the workpiece, wherein the first controller is further configured to store distortion-correction parameters and to use the stored distortion-correction parameters to adjust the first projected output digital image. In some embodiments, the workpiece is a lumber truss.