Advanced Materials Research Vols. 706-708

Abstract: According to the requirements of states monitoring and detection to shearer, it is an urgent need to develop a new states signal collection method, which can solve the current problem in signal collection. In this paper we collect shearer’s states signal by using self-developed portable intrinsically safe mining vibration recorder, which has solved the data acquisition problem of vibration-based shearer fault diagnosis research. This has laid the foundation for states monitoring and detection to shearer, and also for remote monitoring and fault diagnosis to shearer. At the same time, this will provide theoretic reference and basis for design improvement and performance improvement of shearer in future through analyzing the data.

Abstract: Because 4×4 omnidirectional platform which designed has some motion disadvantages, this paper analyses the kinematic characteristic of 8×8 omnidirectional platform and builds the dynamic virtual model to get the translation chararteristic by coordinated simulation. By adding the arm shaft, it can climb the grade with 32 degree, climb stairs and achieve omnidirectional motion on the uneven road. It shows 8×8 omnidirectional platform has good motion characteristic by simulation. And it is the foundation for producing the real platform.

Abstract: The modeling method of 3-dimensional garment model form is the key for the 3-dimensional garment design system. The modeling method of model form will directly have effects on the complexity and presentation effects of the latter design of garment styles. It is also closely related to the garment 3-dimensional al imitation and simulation as well as the transformation relation between 3-dimension and 2-dimension. Therefore, the modeling method of 3-dimensional garment model form is much worthy to study and has a good application prospect.

Abstract: During the city sewage treatment process, pH value has the nonlinear control characteristics of pure lag, large inertia and so on. This paper presents the adaptive system control method based on HDP (heuristic dynamic programming) in view of the above features. Three neural networks which are action, model and critic constitute a self-learning system for the approximate dynamic program the optimal performance index function to realize the optimized control on pH value. The emulation experiments show that this method has better control effects comparing with the traditional method PID on steady-state error, overshoot, response speed and anti-jamming ability.

Abstract: In this paper the principle and method of the ultrasonic thickness measurement are introduced, and a kind of thickness measurement system based on single chip microcomputer is set forth, which is used for shield cutters’ wear measurement. besides, the collected data is processed by way of MATLAB software which can display the intuition image of the present situation of the tool wear and provide the reliable guarantee for real-time detection of the cutting tool.

Abstract: Making the best of solar energy is an important way for human beings to solve energy shortage. Although solar energy is the ideal alternative energy source, its disadvantages, such as low density, intermission and no change of space distribution, not only make it difficult to be collected and used, but also give a higher request to the tracking control system. In order to solve the problem of low utilization ratio of solar energy, it is significant to improve the precision and stability of the tracking system. This paper introduces the working principles and characteristics of the open loop, closed-loop and hybrid tracking mode firstly, the design of hybrid tracking control system is presented next. The solar hybrid tracking mode integrates the advantages of open loop and closed-loop tracking mode, and it can solve the problem of sensor tracking mode which cannot work in the cloudy day and the problem of program tracking mode which exists the accumulation error. As a result, it keeps higher precision and stability under all-weather conditions, and has a broad prospect.

Abstract: To ensure the efficiency and safety of the construction, it needs to monitor the real-time work status of single tower crane and between each other. This paper briefly described the basic application of RFID technology. Then it applied RFID technology to the anti-collision system between two tower cranes and wireless communication system of the tower cranes group. As the important part of the perception layer of the Internet of Things, the application of RFID technology in wireless communication system of tower cranes group could improve the efficiency of the construction. It also ensured the safety of the construction. Finally, it built the monitoring system platform of the construction machinery group based on Internet of Things technology.

Abstract: An effective method to improve and self-identify equipment measured precision is the method of error model best estimate of trajectory(EMBET).Under circumstances of several sets of photoelectric, radar equipment involved in measurement, correlation of error model coefficients was enhanced, accuracy of self-identification and orbit determination was dropped because of close arrange station. This paper uses a method of EMBET based on principal components estimate, and a method of screening method of optimal characteristic roots based on function of residual sum of squares to improve the efficiency of the characteristic root screening, the morbid phenomenon of matrix inversion was effectively eliminate, and the accuracy of self-identification and orbit determination was improved.

Abstract: The ocean current and cable will affect the ROV(remotely operated vehicle) when ROV is working under the sea. Current velocity and umbilical cable disturbing are hard to measure by sensors, which has to be estimated by observer. In order to improve the precision of observer, we present reasonable models for ocean current and umbilical cable disturbance, and design a sliding mode observer which has the same robustness as sliding mode controller. An upper bound of estimation error is derived by using Lyapunov stability criterion. Performance of the observer is verified using numerical simulation.Algorithm is very easy to complie,could meet the engineering needs.

Abstract: Hydrogen is an effective fault gas dissolved in transformer oil, and online monitoring its concentration has important meaning on condition assessment and fault diagnosis of power transformer. A facile and simple synthesis method of ultra-sensitive SnO₂ nanofibers through a hydrothermal approach was reported. The crystalline phases and microstructures were performed by X-ray powder diffraction and field-emission scanning electron microscopy. The gas sensor based on prepared SnO2 nanofibers was fabricated by a side-heated preparation, and its gas sensing performances to H₂ were measured. The fabricated sensor exhibits excellent sensing properties to H₂, such as low optimum operating temperature, high gas response, rapid response and recovery time, good stability and repeatability.