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Qian D.,North China Electrical Power University | Liu X.,North China Electrical Power University | Li L.,China Enfi Engineering Corporation
International Journal of Advanced Mechatronic Systems | Year: 2012

Ball-beam system is one of the most enduringly popular and important laboratory models for teaching control systems engineering. It is very simple to understand as a system, but there exist strong non-linearities and dynamic couplings to illustrate control methods and control concepts. It belongs to a class of second-order under-actuated systems with gravity term and two degrees of freedom. The methodology of hierarchical sliding mode control (SMC) is developed for the class. But it excludes the ball-beam system due to its special dynamic model. In this paper, an adaptive hierarchical SMC law is addressed for the class. By modifying the expression of the hierarchical SMC, the presented method is able to cover the special case. The adaptive law and the control law are deduced from Lyapunov direct method. The asymptotic stability of all the sliding surfaces is proven by Barbalat's lemma and Lasalle's invariance principle. Simulation results show the feasibility of this method by stabilisation control of a ball-beam system. © 2012 Inderscience Enterprises Ltd.

Zhou J.,Central South University | Shi X.-Z.,Central South University | Wang H.-Y.,Central South University | Wang H.-Y.,China Enfi Engineering Corporation
Meitan Xuebao/Journal of the China Coal Society | Year: 2010

Based on the principle of Mahalanobis Distance Discriminant Analysis(DDA), the distance discriminant analysis model to determine the water-bursting source of mine was established. According to the chemical analysis of the aquifer water in underground shafts, six indexes of water-bursting source determination of mine were taken into account to build a forecast DDA model. Linear discriminant functions were obtained through training of thirty-five sets of in situ data. Each of the thirty-five sets of samples was tested by using resubstitution method according to the DDA model, and the correct rate was equal to 97.14% after the DDA model was trained. The other four sets of samples were predicted by using this model to test the discriminant ability of DDA model. Moreover, the proposed method was used to determine water source determination of Wutongzhuang Mine water-bursting. The results show that DDA model classification is good, prediction accuracy is high, misjudge rate of resubstitution is 0.0286.

Yang Z.,Central South University | Yang Z.,China Enfi Engineering Corporation | Rui-Lin M.,Central South University | Wang-Dong N.,Central South University | Hui W.,Central South University
Hydrometallurgy | Year: 2010

A novel hydrometallurgical method was developed to selectively extract base metal values, such as cobalt, zinc, and copper from copper smelter slag at atmospheric pressure. It involves leaching with sulfuric acid and sodium chlorate oxidant and neutralization with calcium hydroxide for better and faster filtration of the precipitate. It significantly decreases or avoids the adverse effects of silica and iron(III) oxides on recycling or extracting target value metals. Four key parameters were explored in this new approach, namely, sulfuric acid consumption, amount of sodium chlorate, reaction temperature and reaction time. Calcium hydroxide was one of most critical factors to precipitate silica and iron(III) oxides before filtration. Once all these four parameters were optimized, the overall extraction and recovery of cobalt, zinc and copper was 98%, 97%, and 89% respectively, while the extraction of silicon and iron was only 3.2% and 0.02%, respectively. This hydrometallurgical process, almost completely recovers the valuable metals of cobalt, copper and zinc from the copper smelting slag without roasting. The proposed leaching method is simple, economical and competitive to operate, so it is readily applicable in industry. © 2010 Elsevier B.V. All rights reserved.

Dou R.,University of Science and Technology Beijing | Wen Z.,Beijing Key Laboratory for Energy Saving and Emission Reduction of Metallurgical Industry | Zhou G.,China Enfi Engineering Corporation
Applied Thermal Engineering | Year: 2016

A 2D axisymmetric inverse heat-conduction model based on the Levenber-Marquardt method was built. The equivalent Nusselt number Nuequ of air jet impinging on a stainless steel plate with finite thickness were obtained. Radiant heat transfer is significant when the temperature of the target plate is high, which induces the nonlinear feature of the inverse heat-conduction problem. The results of the experiments and the inverse analysis provide the following findings. First, the inverse heat-conduction model is accurate. Second, Nuequ maintains a relatively small value before the onset of the air jet. After the air jet starts, however, the values of Nuequ within the stagnation zone (dimensionless radius R/Dn≤&1.0) increase dramatically, reach the peak points in the next 20s, and then remain nearly constant until the end of the experiments. Third, the radial distribution of Nu;bsubesub shows that it decreases rapidly within the region of R/D;bsubesub≤;8.0. When R/Dn exceeds 10, Nuequ appears unaffected by the Reynolds number and R/Dn. Lastly, Nuequ decreases slowly with the increase in time, which indicates that radiant heat-transfer flux decreases with target plate temperature. © 2015 Elsevier Ltd. All rights reserved.

Liao Y.,Xian Jiaotong University | Zhang P.,China Enfi Engineering Corporation
Mechanism and Machine Theory | Year: 2010

The precession behavior of an unbalanced rotor-bearing system with anisotropic supporting stiffness is analyzed. The result shows that the probe-orientation-related problem is still unsolved in the holospectrum technique based rotor balancing method. The deficiency of the balancing object of this method now in use, the Initial Phase Vector (IPV), sometimes makes the description or evaluation of rotor balance state unclear. Necessary modification to this method is made in this paper. A compound balancing object comprised of the magnitude of the major axis and the Initial Phase Angle (IPA) of the precession orbit is presented to replace the IPV as the rotor unbalance response. The amount and angular location of the mass unbalance can be determined precisely by the magnitude of the major axis and the IPA, respectively. Since the isotropic assumption is no longer a prerequisite and the evaluation of the mass unbalance amount is independent of the probe orientation, optimal result then can be ensured. The experiment and real application case verify its capability and feasibility. © 2009 Elsevier Ltd. All rights reserved.

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