An improved automatic control of natural wood routing using ellipse analysis technology to measure grain direction

作者：Hu CS^*; Tanaka C; Ohtani T; Okai R

来源：Forest Products Journal, 2005, 55(4): 46-51.

Under fixed cutting conditions, the surface finish roughness of the workpiece is correlated to the grain angle. Cutting force and acoustic emission (AE) are used to evaluate the grain angle, which is used to control the feed rate to achieve the maximum cutting efficiency and finished surface quality in the online control system of the router. However, the cutting force is affected by its additional inertia and the difference between the latewood and earlywood. Additionally, the linear relationship between AE count rate and surface roughness under every discrete grain angle is complex and the means of determining the grain angle automatically and accurately is still not clear. It is therefore necessary to develop a new technology to accurately determine the grain angle automatically in the control system of the router. In this research, a laser light scattering pattern was used to determine the grain angle. The light scattering pattern image was a quasi-ellipse caused by the grain direction and tracheid effects. A modified Hough transform (MHT) ellipse analysis technology was adopted to determine the ellipse parameters that could be used to determine the grain angle. The results indicated that the measured grain angle by the method proposed here was accurate and effective. Improved automatic control of a wood routing operation using the measured grain angle was developed. In the system developed, the feed rate was optimized to improve the finished machining surface quality by means of the measured grain angle according to the fundamental relationships among grain angle, feed rate, and surface roughness. The experimental results are expected to improve the routing efficiency and the finished surface quality.

• 出版日期2005-4