Advanced Materials Research Vols. 383-390

Abstract: Library construction is a fundamental work in Cadence Allegro’s schematic and PCB (printed circuit board) constructing process. Existing part libraries are normally organized in directory structure. With the increment of the amount of library files, part management becomes slow and error-prone which is carried out on manual basis. A new method is given by designing part management software through applying the SKILL technology to aid Cadence Allegro part management. Application results show that the new method is effective in the library construction.

Abstract: In order to improve the control quality of the water level for steam generator, a fuzzy level controller for steam generator is designed based on the fuzzy logic principle. The fuzzy logic toolbox and Simulink module of Matlab software are used for the modeling of the water level control system of steam generator. The operating condition of reducing load is calculated. Simulation result shows that the fuzzy control has such virtues as smaller overshoot, shorter regulating time and stronger robustness than the conventional three-element PID control. Fuzzy control is especially effective for nonlinear system like steam generator with multivariable, large time lagged and strong coupling. It is a very effective control method with widely application prospect.

Abstract: In this paper, chaos synchronization is studied. Two schemes are proposed to synchronizing Chen chaotic system with all the system parameters unknown. Especially in the last two schemes, only one state variable is contained in the controller. Also, numerical simulations are given to illustrate the effectiveness of the methods.

Abstract: This paper discusses the design of the temperature and humidity monitoring system. It designs from software and hardware aspects in detail. The system included the three modules such as PC, FPGA and some peripheral circuit. Thereinto emphasis is laid on the introduction of hardware and software of communication interfaces of PC and FPGA. FPGA is core controller; PC is used to manage data acquisition and analysis. It introduces the data acquisition based on PXI bus and NI software LabVIEW. The system has the following advantages: its interface is friendly, its circuit is simple, its function is strong and its hardware system is integrated highly. The system realizes the monitoring the multi-humiture storehouses.

Abstract: Accurate analysis and modeling of DC side short circuit transient is important for design of DC traction power supply system and assessment of the suitability of protection arrangement. In recent years, the overshoot and swing in short-circuit fault current profiles of subway traction power supply system can not be correct explained by the existing subway traction power supply system fault model. The second-order transient model on subway traction power supply system is presented by analyzing short-circuit fault current recorder, the commissioning test waveform and electrical parameters of subway train. Using this model, the simulation results are consistent with the fault recorder and the commissioning test current profiles. Also the origin of the overshoot and swing on the waveform is explained.

Abstract: Due to steelwork defects, there is undesired vibration of hoist cage in operation which will influence safety of hoist system. In this paper, 6 degrees of freedom vibration model of hoist cage excited by steelwork defects was established first. Then horizontal and vertical vibration characteristics under different defects as well as relationship between vibration amplitude and hoist load, defect size and hoisting velocity were analyzed through simulation. Finally, simulation model was verified by experiment.

Abstract: A new method is proposed to calibrate the installation errors of SINS. According to the method, the installation errors of the gyro and accelerometer can be calibrated simultaneously, which not depend on latitude, gravity, scale factor and earth's rotation rate. By the multi-position combinations, the installation errors of the gyro and accelerometer are modulated into the sine and cosine functions, which can be identified respectively based on the least squares. In order to verify the correctness of the theoretical analysis, the SINS is experimented by a three-axis turntable, and the installation errors of the gyro and accelerometer are identified respectively according to the proposed method. After the compensation of the installation error, the accuracy of the SINS is improved significantly.

Abstract: It’s of great significance for safe and reliable operation of fan to research on the stall characteristics of the airfoil. The 2D non-compressible Reynolds-Averaged Navier-Stokes equations was built to simulate the flow around the airfoil of G4-73No.8D centrifugal fan, a detailed numerical simulation under different angles has been carried out which based on the Realizable turbulence model with Fluent. The numerical results show that the smaller of the flow rate, the bigger incidence angle is, when the incidence angle is bigger than the critical incidence angle, the suction side stall appears. According simulation the airfoil stall appears when the incidence angle is -28°, with the increasing of the negative incidence angle, the separation point gradually moves to the leading edge. There is a strong vortex which locates at suction side =0.5,the alternating stress on the blade which caused by vortex will make the blade fatigue. If the incidence angle is less than -20°,there is no flow separation, therefore, to ensure the safe operation of the fan, the incidence angle should be less than -20°.

Abstract: This paper designed a set of counter system to hand flat knitting machine based on single-chip microcomputer, for the inconvenient of counter of traditional ones. It used a shading photoelectric switch sensor converted the output of the sensor into standard electrical signal of single-chip microcomputer with converter, then dealed with single-chip microcomputer, and the count value was output by speech at the end . The hardware simulation results show that the design is practical, achieving the schemed requirements.

Abstract: Air conditioning refrigerant leakage is often in the course of one fault occurs, the event of leakage, in a very short period of time cooling system will be unable to function properly. In order to realize the reign of air pipelines leak detection, this article is brought forth new ideas that pipe leak detection of air conditioning is achieved by the stress wave technology and by programming in the development environment of LabVIEW. Experimental results show that this new method is quick, accurate and reliable to detect and to locate the leak source occurred, the system measures the absolute positioning error is less than 0.3% and the relative error is better than 1.5%.