Sawline Log End Tracking With Camera-Based Position Detection
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Solution Overview
Problem
In sawmills, the use of photo cells for controlling sawline processes is unreliable due to interference from chips and sawdust, leading to inaccurate positioning of blades and rollers, which results in quality defects and system malfunctions, and the proposed solution of increasing the number of photo cells complicates automation and increases costs while reducing reliability.
Innovation Solution
A method and sawline system that uses a camera apparatus to determine the length of the log outside the processing apparatus, combined with a control system that calculates the log's end location within the apparatus, allowing for precise positioning of blades and rollers, thereby reducing the need for multiple photo cells and enhancing automation and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photo cells are placed outside the processing apparatus to avoid interference from chips and sawdust, then reliability of photo cell operation is improved, but the distance between photo cells and blades/rollers increases making precise positioning difficult
Solution Approach 1:
The patent introduces a camera apparatus as an intermediary measurement device that captures images of the log from outside the processing apparatus. The camera is positioned where it is not affected by chips and sawdust, yet can still measure the log's position accurately by capturing visual information and transmitting it to the control unit for processing.
Solution Approach 2:
The patent replaces the mechanical/optical photo cell system with a camera-based visual measurement system. Instead of using photo cells that require direct line-of-sight proximity to detect log position, the system uses a camera to capture images and determine position through image processing, eliminating the constraint of physical proximity while maintaining measurement capability.
2Measurement precision
If multiple photo cells are placed before and after the processing apparatus to accurately determine log end location, then measurement precision is improved, but device complexity and costs increase
Solution Approach 1:
The patent extracts the measurement function from the complex array of multiple photo cells and consolidates it into a single camera apparatus. By taking out the imaging capability and using it to capture the entire log, the system determines the end location from a single image rather than coordinating multiple photo cell signals, thereby simplifying the automation system while maintaining measurement precision.
3Manufacturing precision
If photo cells are used inside the processing apparatus for precise control, then positioning precision is improved, but reliability decreases due to interference from chips and sawdust
Solution Approach 1:
The camera apparatus serves as an intermediary that enables precise positioning control without being physically present in the contaminated environment. The camera captures images from a clean zone outside the processing apparatus, and the control unit processes these images to determine the log's position, thereby achieving precise blade and roller positioning without exposing the measurement device to chips and sawdust interference.
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
The camera-based system accurately determines the log's end location, enabling timely and precise control of processing apparatuses, improving the reliability of the sawline operation and simplifying automation by reducing the number of photo cells required, thus enhancing the quality of sawn wood and reducing costs.
Implementation Method 1
The length of the part of the log outside the processing apparatus is determined with a camera apparatus
Data Source
Figure 1
AI summary
Method for operating a sawline (1) for logs (2), which sawline (1) comprises conveying means (3) for conveying a log (2) in the sawline (1), and a processing apparatus (6, 7) for processing the log (2). In the method, the log (2) is fed into the sawline (1), the log (2) is conveyed onwards in the longitudinal direction in the sawline (1), the overall length of the log (2) is determined, and the log (2) is guided into the processing apparatus (6, 7), with which the log (2) is processed at the same time, when the log (2) is conveyed onwards in the sawline (1). The length of the part of the log that is outside the processing apparatus (6, 7) is determined with a camera apparatus (9), and the location of the end of the log (2) in the processing apparatus (6, 7) is determined on the basis of the overall length of the log (2) and on the basis of the length of the part of the log (2) that is outside the processing apparatus