Advanced Materials Research Vols. 1044-1045

Abstract: For the different operation mode of micro-grid, an improved droop control method and a parallel inverter was proposed depending on the study of micro-grid inverter. Grid-connected interface contains a series inverter and a parallel inverter, and can be switched to select different work mode. The parallel inverter can eliminate harmonic, compensate three-phase imbalanced current to improve the quality of the power delivered to the utility grid. In islanding operation mode, the improved droop control strategy was applied, where an integral controller was introduced. So it can reduce the inverter output voltage amplitude. Thereby it can restrain circulation and realize the power of self-distribution. The effectiveness and feasibility are verified by the simulation result.

Abstract: As for a vector control of a permanent magnet synchronous motor, this paper analyzed the influence of dead-time effect of three-phase bridge inverters on output voltage and current in details. A novel on-line method was proposed for dead-time effect compensation based on disturbance observer. At last, the method is simulated using MATLAB and the simulation results proves the effectiveness and feasibility of the method presented.

Abstract: BP neural network has been successfully used in the gas well productivity prediction, but as a result of neural network is sensitive to the number of input parameters, we had to ignore some factors that is less important to the gas well productivity. In addition, the existing various productivity prediction method cannot consider the influence of some important qualitative factors. This article integrated the advantages of fuzzy comprehensive evaluation and BP neural network, fuzzy comprehensive evaluation method is used to construct the BP neural network's input matrix, and BP neural network learning function is used to solve the connection weights, so as to achieve the aim of predicting gas production. This method not only can consider as many factors influence on gas well production, ut also can consider qualitative factors, so the forecast results of the new model are more realistically close to the actual production situation of reservoirs.

Abstract: To obtain a prediction model of the equivalent parameters of rolling guide's joint, an F-P-KC prediction model was established based on force, pressure and equivalent parameters. Firstly, according to the linear assumption of physical parameters within the rated range, an F-P model was established in the consideration of the loads, types and installing modes of guide’s slider group; secondly, a P-KC model was established in terms of the result of the media condition of joint surface; finally, the prediction model was successfully applied in the project, and the feasibility was verified. A new effective way for solving the similar problem is opened up by the model and it also lays a theoretical foundation for the following study of dynamic characteristics.

Abstract: The accuracy of calibration is a critical link which affects the accuracy of the machine vision system. Several factors affecting the accuracy of the binocular vision calibration were analyzed. To construct a reprojection error was as a cost function. Deference controllable factors were set to getting intrinsic parameters. And then reprojection error was depicted utilizing a variety of graphical form, such as 2D coordinate drawings, line charts and cross-hatched map. The correlation between parameters which were paid attention in calibration process was analyzed clearly and directly. The selection of optional parameters is described based visualization. The selection basis of optional parameters was offered by experiments.

Abstract: We present defect detection of polyethylene (PE) pipes by using active infrared thermography technique. A finite element model was built to mimic the transient heat transfer in PE pipes, in which constant heat flux boundary condition was applied to the inner surface of the PE pipes. Various defects with different diameters and depths were simulated in PE pipes and they would affect the thermal distributions from which the relation between thermal images and defect sizes and locations would be established. An electrical heating bar, as the novel thermal excitation source, was employed in active infrared thermography experimental system. The finite element simulation results are well agreed with the one obtained from the infrared imaging experiments and it demonstrated that finite element numerical method can be an effective method to analyze infrared imaging. Furthermore, defects in heat fusion joints of PE pipes were fabricated and detected by the developed active infrared thermography. The experiment showed that active infrared thermography based on an electrical heating bar could provide a novel tool for nondestructive evaluation of PE pipes.

Abstract: In this paper, a camera ranging method for agricultural robot localization in arable farming is described. Three calibration objects in different directions in the field are set. The distances between the robot are calculated, and the calibration objects are used the camera to obtain the robot position. The benchmarking procedure in Matlab includes image binarization of the calibration object and the curve fitting method was used to establish the relationship between the pixels number of the calibration object and the actual distance. The verification results show that the relative error of ranging is less than 1.5%. Furthermore, the camera ranging method for agricultural robot localization is proved to be easy and feasible.

Abstract: This paper introduces the working principle of anti-lock braking control system and detailed classification method, points out that the car special anti-lock control system, and mainly illustrates the anti-lock control system structure and function, at the same time provides several common fault repair methods for reference.

Abstract: In view of biomass gasify process which has nonlinear, non-minimum- phase, big delay and strong load interference characteristics, a fuzzy neural network control algorithm for biomass gasifier is presented. Gasified process of biomass gasifier has been researched, and intelligent control of temperature and primary air flow for biomass gasifier has been designed. The control objects are gasifier temperature and flue gas oxygen content , the regulation objects are the material feed flow and primary air flow. Simulation results show that, this system has better control effect than the traditional fuzzy control system.

Abstract: PCR-SSCP is a technology based on the combination of PCR and SSCP, widely used in such research fields as microorganism identification and microorganism flora. In this paper, the application of PCR-SSCP in bacterial detection and microbial community monitoring is briefly introduced.