Applied Mechanics and Materials Vols. 380-384

Abstract: With the improvement of precision in various fields, we present a new method for the measurement of the absolute distance of a remote target based on the laser interferometry technique. In this paper, we obtain the interference fringes change information (the distance information) with the help of laser scanning with different frequency. It does not require the target to move in the direction of measurement. We have done experiments to compare this new methods results with the results of RENISHAW interferometer. Its improved that the accuracy of distance measurement is 10^-4~10^-5 relatively.

Abstract: [Purpose] Smartphones video cameras can be used to detect the photoplethysmograph (PPG) signal.The pulse wave signal detected by smartphone always mixed mass noise because of finger moving, unevenness of pressure and outer light interference. Previous studies limit to the filtering algorithm that denoising signals, without considering characteristics information of pulse wave itself. [Method] In this paper, we propose an algorithm based on wavelet to detect qualified PPG, which captures three critical characteristic quantities through wavelet high frequency coefficient. [Results] Experiment illustrates that the detected PPG signal contain dicrotic wave, and whats more, further experiment on artery elasticity indexes indicates good robust of the algorithm. [Conclusions] Wavelet Based Measurement on Photoplethysmography by Smartphone Imaging can be used for the calculation of cardiovascular parameter such as angiosclerosis, arrhythmia, and vascular resistance.

Abstract: In the virtual scene of robot assisted virtual surgery simulation system, the surgical instruments achieve complex motion following the haptic devices and the soft tissue deforms continuously under interaction forces. In order to meet the rapidity of collision detection, an algorithm based on changeable direction hull bounding volume hierarchy is proposed. Strategy of combining surface model with body model is developed for soft tissue deformation. Skeleton sphere model of soft tissue is built. Deformation can be achieved based on mass-spring theory after matching collision information with the skeleton sphere model. The experiments show that the proposed collision detection method implements faster speed compared with fixed direction hull algorithm and soft tissue deforms through combination of collision information with sphere model.

Abstract: According to the high fault rate and the great difficulty of diagnosis for the automobile engine, an automobile engine faults detection system was designed. Because the vibration signal of the engine could reflect the faults types to a great extent, a fault detection method was proposed based on the extraction of the vibration signal correlation dimension. The collected vibration signal which was from different type of automobile engines was processed and analyzed. The correlation dimension was extracted and an improved correlation algorithm was proposed in the system, the computational accuracy was improved, and the standard deviation of the improved algorithm lowers about 50% in comparison with the traditional algorithm, the classification performance is raised variously, the excellent detection performance was showed in the system. The detection result shows that the correlation dimension feature extraction method that this paper proposed can detect and diagnose different types of automobile engine faults such as start subsystem fault, ignition subsystem fault, fuel supply subsystem, etc. The detection conclusion was stable and the simulation result has much great application performance.

Abstract: The existing traffic flow monitoring system has some defects, including dispersed data collection, difficult to accurate and real-time monitor the vehicle motion process, low degree of all types of vehicle identification and limited monitoring performance. In order to solve all the problems above, this paper designs traffic flow monitoring system bases on Internet of Things. Using the core data collected by ZigBee wireless communication technique, the system adopts optimal scheduling algorithm to design the system. Simulation experiments are carried out on the basis of real-time collected by the system. The results show that the system achieves high efficiency and performance monitoring of the vehicle types, real-time classification, vehicle coordinate real-time positioning while operation, automatically receive real-time traffic data, and efficient scheduling.

Abstract: According to some bottleneck problems of the communication network bandwidth in wireless video transmission, a design scheme of real-time traffic video monitoring system based on 3G network is put forward in this paper. The design of hardware and the software realization of the system process are mainly introduced. TMS320DM8168 is selected to build the hardware platform in this system. H.264 video encoder is integrated internally. The real-time transmission of video data is sent to the remote monitoring center through the 3G network to improve the video transmission quality. The system meets the requirements of video transmission applied in automobiles.

Abstract: In order to meet the flexibility and real-time of the remote ECG monitoring system and other application requirements, a design proposal of a remote real-time ECG monitoring system based on 3G chip is presented in this paper. ARM9-based embedded control chip S3C2440 is chosen as the core and 3G module SIM5218 embedded TCP / IP protocol stack is used to transmit ECG data of the system which has functions of displaying the real-time ECG waveform and alarming. Thus, the real-time transmission of the large ECG data from the user to the monitoring center has been accomplished in this system. The research of the system provides convenience for the timely rescue of patients with cardiovascular disease.

Abstract: The thickness measurement and monitoring of all kinds of equipment and parts, especially making general investigations on the thickness of boiler, pressure vessel and pipelines regularly, monitoring their thinning after corrosion in the process of using, and ensuring the safety production have attracted more and more attention among the companies. Based on the thickness measurement principle of pulse reflection type ultrasonic, the measurement method of the steel plate thickness was studied, and AVR Atmega16 single chip microcomputer as control chip was used. The analysis and comparison of ultrasonic transmitting circuit, receiving circuit, amplifying circuit, LCD display circuit, keyboard circuit, communication circuit, counter 232 AVR Atmega16 line were also included. The performance of this system regarding the steel plate as sample was tested, and then the data and the causes of measurement error were presented.

Abstract: Aiming at the status of domestic CNC machine tool's low stability of accuracy, stability of accuracy test of 5-axis machining center VMC0656e is done. The concrete scheme of test is presented. The laser interferometer is used to test accuracy of every link and the influence of loading test to accuracy is mastered. Finally, the results are analyzed and the measures to improving machine tool's stability of accuracy are presented.

Abstract: In order to solve the nonlinear output/input problem of the capacitance method measuring the moisture content of green sand, a nonlinear compensation is added into the measurement system and the neural network is used for nonlinear rectification. Based on introducing the principle of non-linear compensation, a functional link artificial network with multi-input and single-output is constructed. In the network, the output voltage of capacitance moisture sensor is taken as the input and the moisture content of green sand is taken as the output. The data samples obtained in laboratory are used to train the network, and the dynamic rectification model is got. The experimental results show that the maximum difference and relative error of the moisture content are ±0.09% and ±1.85% after nonlinear rectification by the functional link neural network, and it is significantly better than those of the least square method.