Advanced Materials Research Vols. 694-697

Abstract: Momentum wheel is a key actuator of the attitude controlling system of the satellite. Thus, it is very meaningful to accomplish its fault diagnosability to maintain the working order of the satellite. Therefore, the operator must be timely to judge change-trend in momentum wheel, figure out the reasons for changing conditions and adjust it promptly. However, the working environment of the momentum wheel is very complicated, targeting on the problems of complex fault mechanisms and uncertainty between fault type and fault symptoms, this paper puts forward a Bayesian network structure based on the FMEA (Failure Modes and Effects Analysis) Bayesian diagnostic network. This method will provide theoretical basis for momentum wheel fault diagnosis and the simulation shows it can detect the fault by detecting multi-fault variables effectively.

Abstract: Diesel spray characteristic s is affected by nozzle geometry and then influences the subsequent combustion and emission, so it's important to get the detail nozzle geometry dimensions. In this paper, the X-Ray phase contrast imaging technique was proposed to measure the nozzle geometry. With X-microtomography technique and three-dimension reconstruction technique, the internal structure of nozzle is constructed. The non-destructive measurement was performed and the detail structure of nozzle was got.

Abstract: Nowadays, it's difficult to stably measure sucrose supersaturation through an online instrument directly. This paper is Nowadays, it's difficult to stably measure sucrose supersaturation through an online instrument directly. This paper is based on the soft measurement principle，extracting the principal component of auxiliary variables in sucrose supersaturation soft measuring with the method of kernel partial least squares, and eliminating the multiple nonlinear correlation among the auxiliary variables and noise interference, building an online soft measurement of sucrose supersaturation and offline soft measurement model，and improving the accuracy of soft measurement . The paper develops the system of sucrose supersaturation soft measurement by using VC + +6.0.

Abstract: A novel method to detect ferroresonance was proposed based on the drastic characteristics of the electromagnetic voltage transformer (PT) current rate. This scheme takes current rate which is greater than a threshold value as starting signal and judges the occurrence of resonance by detecting duty ratio of the peaks and interval angles. Then, it identifies the periods and patterns established on the interval time of spikes. Through simulation testing of MATLAB, it can distinguish the occurrence and types of ferroresonance accurately, which verifies the validity of the detection method.

Abstract: Transient stability control of power system is a non-linear optimization problem which contains many constraints. Considering the cost of preventive control, emergency control and the following restorative control synthetically, a model of preventive control and emergency control based on DSR(Dynamic Security Region) and probabilistic insecurity measurement is proposed in the paper, and the optimal operating point of the system was obtained by using the improved genetic algorithm. In the end, the feasibility of the model and optimization strategy are verified by the case of the IEEE 4-generators 11-nodes system. Simulation show that the cost of comprehensive control of prevention and emergency is 13.2% less than the case that without the consideration of the random factors of the fault.

Abstract: As the characteristic of the indoor, Environment monitoring system is not suitable for wiring, It be designed an indoor environment detection system based on RFD5800 which is wireless transmission module in this paper, and completed the hardware and software design of the system. The hardware system consists of the main control module, the detection module, display module, wireless transmission module and control module. Software includes acquisition program and transfer procedures, and application of fuzzy control algorithm for data integration to improve the measurement accuracy. The system achieved the purpose of real-time monitoring of the indoor environment by detecting

Abstract: Considering the characteristic of fault diagnosis of large steam turbine unit for performance monitoring, a method for performance monitoring and fault diagnosis was designed based on versatile logical form. The logical form was proposed according to fault tree analysis. The diagnostic program can implement the entire process of fault analysis and diagnosis depending on the logical form. This method has characteristics of easy operation and good universality. Design idea and working process of the method were introduced by means of low feedwater temperature.

Abstract: To solve the problem that the workload of measuring complex and large components of platforms is large during offshore platforms constructing, this paper puts forward 3d photogrammetry. With the help of the matlab calibration software tooibox_calib, we calibrate the intrinsic and extrinsic parameters of camera. Then through the measurement of intersected binocular vision, we reconstruct the 3d model of the curved surface.

Abstract: The paper proposes an efficient system to inspect the automotive piston rings. The width of end gap and the degree of light leakage are two significant parameters of the piston ring that must be controlled in a certain range. Due to the small size of automotive piston rings and the large quantity, the paper uses the vision system and image processing tools to detect the piston rings with 80.5mm diameter. The uncertainty of inspecting end gap and light leakage can reach 0.01mm and 2° respectively. In order to improve the inspection efficiency, the paper uses three-position and parallel system, end gap and light leakage are inspected at the same time, it can detect 10 pieces/min.

Abstract: Quick analysis of chemical composition is very important for process control and quality assessment in metallurgical industry, especially in steelmaking process. A prototype equipment for online analysis of molten steel composition was developed based on laser-induced breakdown spectroscopy. The effect of steel temperature on different spectral line intensities was studied, and calibration curves of Cr, Ni, Si and Mn were built. Results show that most line intensities are greatly enhanced when steel temperature is higher than 1200°C, and the detection capability of minor elements in molten steel is higher than in normal solid steel. Line intensity, however, is easier saturated in molten steel, leading to narrow linear ranges of calibration curves for molten steel. Furthermore, for online analysis, by using a median filter the abnormal points were inhibited and the changing compositional concentrations were successfully monitored.