Theory And Technology Of Detecting Inner-Defects In Wood With A Probing Drill Device

Wood nondestructive-like detection technology is a new kind of recent developed detection technology which has been successfully applied in wood production, environmental protection and many other fields. The nondestructive-like detection technique inside timber was discussed in this paper. For different kinds of timber defect has different density, for example, density of empty is little but that of section is higher, rotary probe was pushed into timber and draw different density characteristic information of different position in the course of pushing the probe. The performance of wavelet theory to differentiate faint signal were used to extract and analyze the similar signal of molder. So the similar signal of holes caused by worm and erosion was extracted and analyzed by this method. The detection results were printed through intellectual expert diagnose method and output device.There are many kinds of timber and each kind has its own density characteristic. Density of characteristic in the position with defect are various. Through measuring density inside and in the position with defect, it was discovered that density of defect in timber has corresponding relation to the pressure signal extracted by probe. Mechanism of the mechanical pressure deterred to measure defect in timber was set up.This wood nondestructive-like detection technology is to solve the difficulty which are the extraction way of density characteristic and technology analyzing, de-noising and judging the signal, which can be divided into the following aspects. First, the theoretical foundation of this wood nondestructive-like detection technology -Different timber density reflect different pressure test signal was studied. It is illuminated that this wood nondestructive-like detection technology applied to detect internal defect in timber is feasible and the wood nondestructive-like detecting device was designed; Second, because the pressure of the timber to probe is faint while frictional force, rotation vibrations strength, probe whirling distortion strength is very strong in the course of pushing probe. The key of the detection technique is how to extract characteristic signal from strong interfering noise. So it is the theoretical foundation of analysis and processing the characteristic signal throughthe wavelet theory, which was explained with engineering. The mother wavelet function suitable for testing and analyzing signal was educed by analyzing the concrete performance index; Third, Experimental results show that wavelet can successfully extract the detection characteristic signal and defect signal and has the un-comparable advantage in faint signal analysis aspect. Fourth, wavelet and wavelet packet analysis theory were used to de-noise the actual characteristic signal and succeed in practical application, which guaranteed the testing signal stabile and undistorted and obtained ideal result; Fifth, the controlling and relevant communication system software in the wood nondestructive-like detection technology was researched and designed. Finally, intellectual expert diagnose system used to analyze and research the defected characteristic signal from wood nondestructive-like detection technology device, which successfully discriminate t characteristic information distinguished difficultly, such as cavity, moribund, worm's eyes and crackle. Through setting the course of pre-analysis, characteristic amount extraction, characteristic amount contrast, theory judgment, experience confirm, defect timber can analyzed by intelligent diagnose system.In this paper, wood nondestructive-like detection mechanism of the mechanical pressure deterred to measure defect in timber was discussed systematically. It is the first time to apply wavelet theory to wood detection successfully and study and manufacture wood nondestructive-like detection device of the mechanical pressure deterred to measure defect in timber with intelligent diagnose system.After tested, all the technological index and detection performance of the device are super to tha...