Log rotation accuracy has very high impact on the sawing line yield. In studies of rotation with Scandinavian logs, it has been found out that the best and worse rotation may have even 9% difference in yield.
This has also been noticed in practice, when operator run “joy-stick” control or obsolete log scanner has been replaced with modern digital log scanner and real-time log rotation control. As an example of this new development Profi-TC working principle is described.
Real-time log rotation control
Profi-TC HF log rotation real-time control system is based on texture analysis of the log surface.
All log surface color and contrast changes are so called texture. From a picture taken of log surface, the scanner calculates a mathematical model of texture, which can be tracked in following consecutive pictures, thus being able to tell the rotation of the log at any given moment and also being able to tell, when to stop the rotation at the right time.
Profi-TC HF scans and calculates log texture in real-time 180 times/s. The scanner is positioned either in front or inside (integrated) rotation mechanics. The purpose of Profi-TC HF is to rotate the log exactly according to the angle decided by the log scanner.
With the latest mechanics, PLC controls and scanning techniques the average error of log rotation is 0 degrees and standard deviation as low as 3-4 degrees.
Profi-TC HF rotation control compensates automatically any systematic error in log rotation. For example, tilting roller spike wear and tear causes under turning in the long run, which Profi-TC HF will automatically compensate.
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