Applied Mechanics and Materials Vol. 472

Abstract: Control valve is a kind of essential terminal control component controlling the parameters of fluid such as flow and pressure in process-control. However it is a complex nonlinear, multi-input and single-output (MISO) system that is hard to model by traditional methodologies. To establish the pressure model of control valve, this paper presents a Hammerstein modeling method based on the least squares support vector machines (LS-SVM). The linear model parameters and the static nonlinearity of Hammerstein model can be obtained simultaneously by solving a set of linear equations followed by the singular value decomposition (SVD). As an example, a set of actual production data from a controlling system of chlorine in the salt chemistry industry were applied. The simulation results demonstrate that the obtained LS-SVM Hammerstein model can efficiently approximate the pressure of a control valve. Furthermore, the proposed LS-SVM Hammerstein model can be used in artificial intelligent control and the default diagnosis.

Abstract: Bioprocess automation is developing fast for the reasons of quality control, production cost reduction et. al.. Bioreactor is the central equipment of bioprocess. Construction of computer controlled bioreactor is need for bioprocess automation. In this research, a two level hierarchical structure computer control bioreactor system is designed and constructed. The lower level plays the major role of set-point feedback control of process variables and the higher level plays the major role of graphical human interface and biological mathematical model solution. This control system has advantages of high reliability and flexibility than the single level digital control system, and has plenty of functions and high practicality compared with a normal commercial one.

Abstract: To improve the accuracy of detection and classification of egg with cracks, this paper is to add Support Vector Machine to neural network to automatically identify and classify the eggs with cracks. Firstly process the egg images with light-transmitting were obtained by the computer vision device including denoising, threshold segmentation. Five characteristic parameters of crack areas and noise areas were acquired. Secondly train SVM Neural Network and identify the eggs with cracks by five parameters data as the sample data. The correct discerning rate of grading table eggs is 98.07%. It proves better than traditional method in terms of prediction accuracy and robustness. The generalization ability of SVM Neural Network is strengthened.

Abstract: In paper dryer section of the paper machine, paper dehydration is small, but the steam consumption for the process of dehydration is very large, this steam consumption has a great influence to the total steam consumption of the whole papermaking process. A method optimization of the dryer section based on genetic algorithm is proposed to reduce the dryer section steam consumption, which can reduce the total steam consumption of the papermaking process. After analyzing steam consumption of the whole drying process, the result is that the temperature of dryer section air is the key factor that influences the steam consumption. The model of paper machine dryer section is build with supply air temperature as a variable and steam consumption as the objective function, then using the genetic algorithm to optimize the supply air temperature. Simulation results show that after optimizing air temperature by genetic algorithm steam consumption of papermaking process is further reduced.

Abstract: Flying wing configuration is a promising candidate for various kinds of unmanned aerial vehicles. However, this kind of configuration eliminates conventional vertical tail and rudder, thus existing severe problems on yawing control. To make the flying wing configuration into practical use, it is especially necessary to gain a deep understanding on the control characteristics of yawing control devices. To the innovative yawing control device: split-drag-rudder, which is most widely used on flying wing configuration, the paper introduced its current research and mechanical feature, then carefully analyzed its yawing control characteristics, three-axis control coupling effect, also influencing regularities on aerodynamics and stabilities. The conclusions can help to provide basis on engineering application for split-drag-rudder, and to some extent, help to solve the yawing control problem for the flying wing configuration.

Abstract: The cooling process of unsteady temperature field in the automobile passenger compartment is simulated , making use of computational fluid dynamics software FLUENT and the algorithm of PBCS ,and two equation model is replaced with the three-dimensional turbulence model. And then the workflow is established, which includes DOE, optimization algorithm, approximate model and the numerical simulation. Numerical simulations uses experimental design method to collect data for analysis into the relations and trends of the supply-air direction and the cooling efficiency.The sample points train approximation model, using radial basis function (RBF) neural network approximation model instead of the high cost of the simulation calculation. Multi-island GA is chosen to optimize the supply-air direction. The supply-air direction optimized and the supply-air direction vertical surface of inlet tuyere are calculated by simulation software respectively.Results show that the optimized direction making the car chamber cooling effect is remarkable, by the analysis of the heat flow value and temperature contours of before and after optimization.

Abstract: Efficiency of Photovoltaic (PV) array is affected by surface temperature, solar irradiance, shadow and shape of the PV array. Under partially shaded conditions, the maximum power point tracking method will be hardly controlled since the output power characteristic of the PV array is complex with many spikes. In the present study, characteristics of PV array were therefore established under partially shaded conditions by using Matlab/Simulink. The output characteristics of the PV array under partially shaded conditions were calculated and analyzed. These output characteristics significantly depend on the solar irradiance, surface temperatures, cases of shadows, configurations of the PV array, and numbers of PV modules under partial shadow. The present results are good to designate a PV power generation system by using the power point tracking method.

Abstract: Linear Interpolation methods for predicting the I-V characteristics for c-Si PV modules in outdoor conditions have been used by various groups of researchers. This is essential for minimizing the uncertainty in predicting essential photovoltaic parameters of interpolated I-V characteristics. A near optimum value of empirical co-efficient used in Tsunos model has been investigated under typical Eastern Indian Climatic conditions.

Abstract: This paper presents analysis of impact of synchronous machine based distributed generation (DG) in distribution networks at various penetration levels. Higher DG penetration level raises important issues about distribution system operation. Therefore, new techniques are needed to determine the maximum amount of DG that may be installed without requiring major changes in the existing electric power system. In this paper, DG is placed at the terminal points of the lateral one at a time and both real and reactive power is injected at power factor ranging from unity to zero. Limiting factor for maximum penetration primarily taken is load bus voltage at upper voltage limit of 1.05 pu. Variation in substation voltage is taken as another important constraint. System under consideration for studies is the radial distribution network originating from Chaumala Substation that is situated in Kailali district of Nepal. This paper reveals that maximum allowable voltage rise perspective is recommendable if substation voltage is regulated at 1.05 pu but if substation voltage is kept at 1.00 pu, highly utopist scenario of penetration occurs. So, conductor ampacity or line loading perspective shall be suitable. Further, if DG is injected taking substation voltage at 1.05pu, there is a chance of under voltage at bus that is situated at the end of the critical branch. On contrary, if substation voltage is taken to be 1.00pu, voltage dip is severe at the bus situated very close to substation.Lastly, if the DG is placed closer to the substation, its penetration level should be increased and vice versa.

Abstract: Renewable Energy especially wind energy integration has attained profound growth across the worldwide power system. Wind energy integration at large scale comes up with the challenge on voltages and reactive power management at power system level. The research work presented in this paper has analyzed the impact of wind energy on reactive power reserve with special reference to Hebei Southern Power System. The maximum wind power integration capacity is calculated, and the effect of increasing wind power integration on voltage profiles is studied. Possible controls from system sides and its effects on wind power integration are explored. Study shows that with the increase of the wind power integration capacity, the intermittency and variation will bring more serious problems to the system frequency regulation, reserve service and voltage control. These problems also become the limiting factors for further increase of large-scale wind power integration. In order to make a better use of wind power resources in Heibei province and maintain system safety at the same time, further research should be performed on exploring the reactive and active power regulation and control of the wind farm and the methods to decrease the variability of wind farm outputs.