Advanced Materials Research Vols. 291-294

Abstract: Three main technical problems on heavy equipments fault diagnosis are all solved in the following three aspects. Firstly, build fault trees with the help of reachability matrix. This fault tree building method is helpful to short the labor and time for building fault tree; secondly, design a rule-based reasoning algorithm on the fault tree to avoid the shortcomings of traditional minimal cut sets (MCS) solution; thirdly, design out a new knowledge database structure for fault trees and rules storage. This structure could meet the need of the algorithm; so that the algorithm could be run well with this knowledge database .At the end demonstrate advantages of the fault tree based diagnostic intelligent system with an example.

Abstract: WEDM as a special processing method is widely used in the manufacturing. Focused on the hardware and control strategy of servo control system deficiencies, a new design plan is proposed for WEDM servo control system based on DSP. Author takes TMS320LF2407A DSP chip as core processor for the system, development of the servo feed control system. In the designing, depend on detection circuit output signal which reflect discharge gap state load, the normal spark discharge and short circuit, and be processed by the corresponding module of DSP, the principle is that get the best spark rate.

Abstract: This paper presents a proposed energy saving system for street lamps based on single-chip microcomputer. In this case, light control timer, smart sensor, wireless transceiver, microcontroller smart regulator and other related techniques are utilized to fullfil a ‘green lighting project’. It can not only automatically turn on or off the master switch according to the local sunrise and sunset, and sooner or later, sunny day, rainy days or the actual brightness of the different lamps, but also control each single lamp intelligently. The system can be widely used in road and tunnel lighting, building lighting, and other fields as well as a variety of energy-saving control dimming voltage based intelligent control areas.

Abstract: Torsion test is an important means of determination engineering materials mechanical properties, a high accuracy twist angle measurement method is designed. The twist angle signal is acquired through grating and infrared photocell by Moiré fringe, then interpolation twist angle signal with high-frequency pulses, so as to convert it to pulses, the twist angle is received by processing pulses. This measurement system combined with FPGA and SCM, the function of FPGA are generating pulses、interpolating twist angle signal and counting the pulses, the result of count is processed by SCM. The twist angle accuracy is 0.002°.According to the experiment results, and the main errors of this system are received, they are signal processing error、electric conversion error and concentricity error. The errors sources are analysed, disposal methods for the errors sources are presented.

Abstract: A set of plasma cutting tracking device for spiral SAW pipe was designed. This system is consist of two speed sensors, DC servo motor, gear retarder, a vehicle with plasma torch drove by double screw and nut, speed proportion regulating circuit for vehicle and steel belt based on single chip microprocessor. Tracking and controlling soft ware was programmed in STC12C2052AD.

Abstract: Drainage system is one of the important sub-systems of coal mine integrative control platform[1], and is used to guarantee the safety of mining and auxiliary transportation under the ground. The functions of drainage system are defined, the network framework is designed, the start and stop procedures of the pump engine under the manual control mode and automatic control mode are described, and the determining methods based on liquid level to control several pumps in automatic mode are analyzed. By using Simense PLC module, power source module, digital module, analog module and touch screen hardware, the drainage system control platform is set up, which is connected to the control computer on the ground by using Simense communication module and industrial ring Ethernet[4], and achieved the purpose of remote control.

Abstract: The rotating ramjet is a new conceptive engine based on the ram-compressed technology rely on high-speed rotating rotor, the engine’s core component is an internal combustion rotor, which has the functions of compressing air, combusting and doing work by exhausting. In order to predict the combusting flow field in Ram-compressed Rotor chamber, the model of Ram-compressed Rotor was set up. The fuel composition was defined in software prePDF. Realizable was used for the gas phase turbulence. Fuel particles phase makes use of stochastic tracking model. The Structure characteristics of the combusting flow field and temperature field were found out by numerical simulation. The numerical simulation results show that the combusting flow field in the Ram-compressed Rotor Chamber has simple inlet and outlet is well, and offer the references to the design of combustion chamber especially the contour design of the scramjet nozzle.

Abstract: Electromechanical control CVT (EM-CVT) is a new type of continuously variable transmission, and its ratio quality is an important parameter validated the performance of vehicle. In order to study the dynamical coupling technology between EM-CVT and engine under the running state of vehicle, the special character of two working models is obtained by engine experiment; according to the principle of the EM-CVT, the relation between vehicle speed and ration is theoretically analyzed. Based on the basic theory of PID control, the improved PID control algorithm is proposed for the speed ratio control of the EM-CVT, and experimental verification is made. The experimental results show that there is a significant effect on the system with this algorithm.

Abstract: In this thesis, a model of water injector is established, which can prevent water from splashing when high-velocity flow pours into a container. With the periodic boundary, the 1/18 calculation domain model is built. Then two-phase flow numerical simulation research is done on the device with the steady VOF model. The influencing factors of water injector's performance and the variation laws under different working conditions are obtained. The reliability of the results is improved by comparing the results from different calculation methods with that from steady-state VOF method. And through the experimental researches on the splash-proof water injector, the accuracy of the numerical simulation results is validated.

Abstract: In direct torque control system for induction motor, the system has big torque ripple and strong noise caused by torque ripple. In indirect stator-quantities control, a slip frequency controller, based on power frequency exponent integration reaching law sliding model, is adopted by using practical measure velocity and calculation torque of motor flux model. The slip frequency error is fast convergent and stable in the nearby zero value, the method reduces torque ripple and improve dynamic and stable performance. The stability analysis of the scheme is given by using Lyapunov method. The simulation results verify the effectiveness and correctness of the method.