Applied Mechanics and Materials Vol. 150

Abstract: Failure probability of a component is the major project of engineering probability. The reliability of a mechanical system or a structural system is calculated by components in the system. However, statistics data shows that the distribution of test data of components is not according with the distribution by theory as normal distribution. Normal distribution is extensively applied in the component reliability nowadays. Its domain is the field of real numbers, whereas, test data of exper-iments are on a finite field. Consequently, the component reliability used the normal distributions has some limitations. It is necessary to choose a suitable distribution in the calculating method. Comparing the normal distribution density curve and the statistics graph, a new distribution is pre-sented in this paper. The examples by both normal distribution and the new distribution are given, respectively. The results suggest that the new distribution is more accurate than normal distribution in the component reliability.

Abstract: This paper presents a discrete optimization algorithm based on a model of symbiosis, called binary symbiotic multi-species optimizer (BSMSO). BSMSO extends the dynamics of the canonical binary particle swarm algorithm (CBPSO) by adding a significant ingredient, which takes into account symbiotic co evolution between species. The BSMSO algorithm is evaluated on a number of discrete optimization problems for compared with the CBPSO algorithm. The comparisons show that on average, BSMSO outperforms the BPSOs in terms of accuracy and convergence speed on all benchmark functions.

Abstract: Permanent magnet axial bearing axial stiffness analysis is critical in the design process of permanent magnetic bearing. This article establishes the axial magnetic model through the equivalent magnetic charge method, but the equivalent magnetic charge method solving the axial force need work out four complicated quadruple integrals. The calculation cycle the traditional method is too long, and even cannot get analytical solution. On the contrary, the method of through Forcal language programming to approximate computation bearing axial force makes the solving process simplification. The stiffness of the permanent magnet bearing with equivalent magnetic charge method is verified by comparing the simulating result obtained by using the finite element method. The conclusion is that the equivalent magnetic charge method can be used to calculate the axial stiffness of permanent magnet bearings and provide the basis of the axial permanent bearings design.

Abstract: This paper proposes a novel radial hybrid magnetic bearing (RHMB), whose configuration and working principle are introduced, and its mathematical model is built using the equivalent magnetic circuit method. A simple and practical method for calculating leakage coefficients is proposed to improve the accuracy of the equivalent magnetic circuit method. A 3-D finite element model of the RHMB is established by the software ANSYS and the leakage coefficients of control and bias fluxes are calculated, respectively. Based on the obtained leakage coefficients, magnetic forces on the rotor are calculated using the equivalent magnetic circuit method, and the results are compared with those of experiments and the finite element method. It shows that the magnetic forces obtained using the three methods are in agreement with each other, which verifies the correction of the proposed method in the calculation of leakage coefficients.

Abstract: The digital PID controller system for magnetic bearing was described in this paper which combined Matlab technique with simulation of the magnetic bearing control to reach the influence of parameters of digital PID controller for magnetic bearing control system. The application of the expansion coefficient critical proportion for turning parameters of digital PID controller can achieve better results. Finally, provide a simple and efficient method for numerical controller of magnetic bearing.

Abstract: A novel decoupling control method based on neural networks inverse system is presented in this paper for a bearingless synchronous reluctance motor (BSRM) possessing the characteristics of multi-input-multi-output, nonlinearity, and strong coupling. The dynamic mathematical models are built, which are verified to be invertible. A controller based on neural network inverse is designed, which decouples the original nonlinear system to two linear position subsystems and an angular velocity subsystem. Furthermore, the linear control theory is applied to closed-loop synthesis to meet the desired performance. Simulation and experiment results show that the presented neural networks inverse control strategy can realize the dynamic decoupling of BSRM, and that the control system has fine dynamic and static performance.

Abstract: The bearingless synchronous reluctance motor (BSynRM) is a multi-variable, nonlinear and strong-coupled system. To solve the difficult problem of precise decoupling in electric torque and radial suspension force control, the theory of direct torque control of traditional synchronous reluctance motor are applied to the torque control of a BSynRM in this paper. Based on mathematical models of the BSynRM, A direct torque control algorithm based on space vector pulse width modulation (SVM-DTC) is deduced. The SVM-DTC control system is designed and simulated. The simulation results show the control algorithm of SVM-DTC realizes decoupling in electric torque and radial suspension force control. The static and dynamic performance of electric torque, speed and radial suspension force of the BSynRM is excellent.

Abstract: This paper describes the wavelet transform theory, and traveling wave theory. When the power system transmission line fault occurs, the fault signal generated by sampling and analysis, and use a method of one-end fault distance measurement in transmission line. Finally the article gives the ranging devices’ hardware and software design.

Abstract: With the development of bandwidth wireless communication technology, the testing technology has been improved, and the Distributed Remote Integrated Testing Technology has emerged, which covers the network, software, computer, virtual instruments and co-ordinate technology. Base on analyzing the application of the wireless communications testing technology, the paper states the framework key technology and research points. At last, it gives a detailed application example in the real outfield.