Applied Mechanics and Materials Vols. 341-342

Abstract: This paper proposes an embedded face recognition system solution. The core of hardware architecture of the system is TMS320DM642 digital signal processor (DSP). The face recognition algorithm of the system mainly comprises improved face detection algorithm which is based on skin color, Gabor wavelet feature extraction algorithm, Principal Component Analysis (PCA) algorithm and nearest neighbor classifier algorithm. The results of testing on recognition efficiency and execution time show that the system can work stably and realize face recognition quickly and accurately.

Abstract: The most basic understanding for a new mechanism is to realize its mobility. But there is little theory about mobility of hybrid mechanism in kinematics. Due to the complexity and particularity of hybrid mechanisms, the mobility of hybrid mechanisms cannot be obtained based on traditional methods. In the paper, the constraint and mobility of a dendritic-hybrid mechanism is analyzed based on screw theory. The complicated loops in the dendritic-hybrid mechanism are regarded as generalized kinematic chains, which can simplify the hybrid mechanism and correctly receive the number and characteristic of mobility.

Abstract: As an important part of the CTCS-3 train control system, the on-board subsystem is a safety critical system, and it plays an important role in assuring the safety of train. In this essay, we choose a hybrid testing method combined with the advantage of black-box and white-box testing method in the test of the Simulation of on-board subsystem of the CTCS-3 train control system. The main idea is to divide the tested system into several functional parts, and then test them step by step. At last, we use an example to show the advantage of this testing method in reducing the number of test cases. 1 Current situation in the testing of train control system at home and abroad Train control system plays an important role in ensuring the operational safety of the train, At home and abroad researchers attach great importance to the testing of the train control system, and also a lot of research has been done. The simulation test makes it easier for the testers to work in the lab instead of the field, so that it reduce the human and material costs, and the test environment can be controlled and repeatable easily. Besides, the special environment of the site can also be simulated. University of Florence in Italy has developed the loop of the ATP / ATC test system based on the simulation technology HIL (Hardware in Loop), it provides an effective solution to the test of ATP speed measurement device. CEDEX LIF laboratory in spain simulation has used the test method of simulation to establish the Eurocab test platform, and developed a number of testing tools, moreover, they have defined test sequence. Test sequence generation and viewing, test management and test result analysis and evaluation function have also achieved. Beijing Jiaotong University in China rail traffic control and security National Key Laboratory of CTCS-3 train Control System has also established simulation test platform, so that simulation test can be performed.

Abstract: Common software synchronous sampling methods have some shortcomings such as sampling synchronization error, sampling interval error accumulation increment and so on, and the impact of this error on the measurement accuracy can not be ignored [1]. In this paper, analysis on synchronization error occurrence reasons was performed, and proposed the synchronization implementation method of asynchronous sampling. This method can track the real-time changes of electrical signal by the zero-cross-over triggering circuit, and reduce the synchronization error by the software method. Simulation analysis of the signal cycle (frequency) and RMS measurement shows that proposed method improves accuracy of the electrical signal parameters measurement based on microprocessor technology.

Abstract: According to the analysis of control structures of the two typical control modes-tilt control and course control, the simplified control rules for the two special control systems are presented. Under the condition of enduring the real-time property and fidelity, the classical control theory is applied to study the control parameters selecting of the flight control system (FCS) based on PC modeling traits. The selecting process of control parameters of lateral control channel is analyzed and the simulation resources are simplified. The simulation model is achieved. The steps are summarized for the simulation modeling of lateral control channel of the flight control system, and the corresponding flow chart based on PC is also given.

Abstract: For low-pass filtering of airborne gravity data processing, elliptic low-pass digital filters were designed and filtering influences of the elliptic filter order, upper limit passband frequency, maximal passband attenuation and minimal stopband attenuation were studied. The results show that the upper limit passband frequency has the greatest effect on filtering among four parameters; the filter order and the maximal passband attenuation have some influence, but instability will increase with larger order; the effect of the minimal stopband attenuation is not obvious when reaching a certain value, which requires a combination of evaluation indicator accuracy to determine the optimal value. The standard deviations of discrepancies between the elliptic filtered gravity anomaly with optimal parameters and the commercial software result are within 1mGal, and the internal accord accuracy along four survey lines after level adjusting is about 0.620mGal.

Abstract: With the wide application of temperature and humidity detection system, the requirements and standards of which in different industries and fields are various. After the analysis of domestic and foreign warehouse intelligent temperature and humidity control, the author has found a series of factors of that, and then puts forward a design of scheme of temperature and humidity detection system based on AT89S51, together with a plurality of digital temperature sensor DS18B20 and the humidity sensor HS1101, temperature and humidity detection system is formed.

Abstract: Traditional analog-controlled DC/DC converter can only employed easy control method and always has complicated hardware structure. Its extremely unfavorable in improving efficiency and reducing the cost of hardware. In this paper, a new full digital control method has been proposed. This method employed an advanced main circuit topology combining with an ARM MCU, it can reduce power supplys volume and cost, improve its efficiency effectively. The Topology of main circuit is reasonable, the design of parameters was right. All the results were consistent well with theory analysis. The power supply can realize leading legs ZVS and lagging legs ZCS in a big load range. The whole system has concise hardware structure, reliable control method and good man-machine interface, so it has high practical value.

Abstract: According to the analysis of mathematical model for permanent magnet synchronous motor (PMSM), direct torque control(DTC) technology is introduced to the control system of PMSM. The paper builds dual-closed loop control system of PMSM, and the outer loop is speed loop, the inner loop is flux and torque loop, at the same time, the paper makes simulation in Matlab/Simulink. The simulation results show that the DTC technology significantly improves the dynamic performances of PMSM, and the control system is no overshoot, and has small flux response comparing with the conventional control methods of PMSM. So the application of DTC technology in PMSM provides a new thoughtful way for PMSM control system designing and debugging in actual application.

Abstract: According to the analysis of mathematical model for permanent magnet synchronous motor (PMSM) in the d-q coordinate system, space vector width modulation (SVPWM) technology is introduced to the design of PMSM control system. The paper builds dual-closed loop control system of SVPWM for PMSM, and the outer loop is speed loop, the inner loop is current loop, at the same time, the paper builds the simulation models and makes simulation in Matlab/Simulink. The simulation results show that the SVPWM technology applied to the control system of PMSM is very successful, and the dynamic performance of control system is very good. So the application of SVPWM technology in PMSM provides a new thoughtful way for PMSM control system designing and debugging in actual application.