Applied Mechanics and Materials Vols. 670-671

Abstract: This paper presents a method of measuring the volumetric tool wear by use of the image processing technique. A single CCD camera based stereo vision system is built to acquire the image pair. The crater wear’s boundary of the cutting tool is then detected, and then the 3D volumetric shape of the worn region on the rake face is reconstructed through the developed image matching algorithms, and the crater’s volume and depth is estimated. A Matlab software system is developed to perform image acquisition, calibration, image rectification, image adjustment, stereo matching, crater’s depth estimation, and the representation of the volumetric tool wear. The feasibility of the proposed method is verified through experiments.

Abstract: Aiming at the condition of the strong background noise, many interference sources and unknown the number of sources in the actual industrial field, a method based on multi-scale multi-structure close-open average combination morphological filtering(C-OACMF) and sparse component analysis (SCA) was proposed to deal with the blind source separation problem of rotation machines. First, the C-OACMF was used to filter out background noise signals and extract the characteristic signal of observation signals, then using the simulated annealing genetic algorithm of fuzzy C-average clustering algorithm estimates the mixing matrix, the linear programming is finally used to estimate the source signals. Through the actual environment composite rolling bearing fault vibration signal extraction experiments verify the effectiveness and accuracy of the proposed algorithm.

Abstract: This paper presents a PXI-based biomedical electrical impedance tomography (BEIT) system and interprets how to build up a practical BEIT system quickly. The hardware platform of the system is composed of signal source module, switch module, signal conditioner module and PXI-6251 data acquisition card supplied by National Instruments (NI), which simplify the system structure as well as improving the stability and accuracy of the system. Different from the traditional BEIT systems, the electrodes selection, the switch pattern, the programmable gain amplifier (PGA) gain selection are realized by code programming in LabVIEW instead of electrical components design. The composition of the proposed system and the specialized software package developed in LabVIEW are introduced in detail in the paper, and experiments are undertaken to verify the feasibility of the system. The imaging results verify that the PXI-based BEIT system has prominent performance in flexibility, reliability and scalability.

Abstract: The indoor air quality is very important at any workplace. The air quality accidents and problems are analyzed. Based on the air quality standard and benchmarks, the test and monitor data can be compared. So the air condition system operation status can be evaluated based on the data, the potential causes can be drawn, and the improvement actions and suggestions can be recommended in the paper.

Abstract: Based on the working principle of the capacitive sensor, according to the requirements of deep hole diameter measuring, a capacitance probe sensor was designed, and then the design and type-selection of probe structure, cable inner structure to the capacitance probe sensor were done. At the same time, in order to overcome the measurement error caused by eccentricity, the capacitance sensor probe and inner hole of the corresponding fastener both are designed to a taper, taper positioning is relatively accurate positioning way. The design is to avoid the measurement position offset, and ensures the coaxality on the mechanical structure. The equipotential ring technology effectively overcomes the problem of edge effect of capacitance sensor, and makes the probe’s effective measurement electrode under the condition of limited long, can effectively guarantee the measure precision. By moving the capacitance probe in the hole to the different position, we will realize the deep hole diameter measurement in different cross section.

Abstract: This paper considers the application of flexibility sensors and wearable technologies on smart textiles to enhance the functionality of clothing and protective textiles for the benefit of people, especially older people. By introducing flexibility sensors based strain sensors, we can find its potential of the flexibility science in developed clothing and protective textiles. It has promising application on smart textile products and services appropriate to the needs and aspirations of active users. It shows us how the appropriate design of flexibility sensors has the potential to promote independence and wellbeing, and may enable participation in healthy exercise in the everyday lives of the active ageing.

Abstract: As a relative locating method, machine vision is generally used for automatic navigation of cotton cultivator or cotton insecticide sprayer. However, it is difficult to achieve reliable and stable recognition of crop row with monocular stereo vision system, because it neither can access directly to the depth information of the image, which leads to massive time-consuming calculation, nor possess high-accuracy recognition or a good anti-noise property. This paper presents an algorithm for cotton row detection based on binocular stereo vision to be used for automatic navigation of cotton cultivator. The Zhang's plane calibration is used to obtain the internal and external parameters of the binocular stereo vision. Preprocessing means are applied to distinguish the cotton from soil, stereoscopic match is conducted according to the SIFT operators after the preprocessing of images, after which cotton space three-dimensional coordinates are acquired by parallax distance measuring method, with the elevation information combination of Hough transform, cotton lines are finally detected. The detection results indicate that this method has an accuracy higher than 90%, which primarily meets the need of automatic navigation for cotton cultivator.

Abstract: On-line monitoring device for SF₆ humidity based on ZigBee was composed of processors, signal conditioning units (SCU), data-collection devices, ZigBee wireless network communication technology, control equipment of ventilation and alarm and powering circuits. Data information of humidity, temperature and pressure of SF₆ gas can be monitored by the device. The application of information blending technique decreased the error of measuring, and achieved auto-calibration of measurement systems, compensation of measured data and signal output control, and improved precision of the reliability of measurement, and extended the service life.

Abstract: Transducer with large directivity and high transmitting sensitivity is designed and fabricated. It is a sandwich transducer with composite horn and it has a finite baffle. A novel model considering the dimension of baffle is deduced, the directivity of transducers are calculated under different conditions. The computations of models agree with the experimental data well. The maximum transmitting voltage response level of the sandwich transducer is 143dB (1V/μPa) and the directivity is up to 99°(-3dB) at the resonance frequency of 75.6kHz.

Abstract: Large rotating machinery is widely used in industrial production process. With the computer network technology, system testing technology, signal analysis and fault diagnosis technology, large motor based on high speed wire rod production line as the object, the online monitoring method of large motor is present. Based on it, the signal processing approach of large motor under complex circumstance is proposed, and the software of on-line monitoring system for large motor is developed. Through monitoring the key parameters of the distributed signals of temperature, pressure, current and so on, the developed system can accurately analyze and locate critical faults of equipments, reduce faults rate, extend the service life and increase productivity of the motor equipment.