Applied Mechanics and Materials Vol. 459

Abstract: In order to analysis wave characteristic of drainage wire, considering the shortcoming of existed measuring systems, including lack of accuracy and heavy load of data transmission, and combining with the PDR system which has been widely used in absolute position of a pedestrian, the on-line monitoring method for drainage wire galloping is proposed, which is based on accelerometer and gyroscope. Min-vector of angular velocity is applied to capture the onset/end of each gallop. ZUPT algorithm is implemented to correct the galloping velocity at onset when errors existed. Cluster sampling and quadratic integral are used to measure Galloping parameters accurately. The galloping orbit is also displayed dynamically. Finally, practical experiments are carried out. The feasibility and availability of the on-line monitoring method based on PDR system are demonstrated. The method can measure wave amplitude, wave speed and wave trajectory precisely, and offer technical support for in-depth research of drainage wire galloping.

Abstract: Large scale wind power integration into the Inner Mongolia grid has brought new problems to the wind power accommodation in the present time. Key factors of the accommodation were summarized from which impact on wind power integration, including system voltage, transient and frequency stability, power relay protection, short circuit of wind power plants, power dispatch, etc. Based on the analysis of the wind power developmental characteristics in Inner Mongolia, some measures are proposed to improve the wind power accommodation ability, including the applications of distributed energy system and energy storage system to make better friendliness of wind power integration, as well as the enforcement of grid-connected operation characteristics of wind turbine and wind power dispatch levels to strengthen the security of the wind power integration.

Abstract: With economic development, power load is continuing to grow, power scale and install capacity have somewhat expanded. While there are some uncertain factors which lead to the power insufficient, and bring great losses to the development of national economy. This paper base on equivalent continuous load curve and curve fitting theory, establish mathematical model, and research the reasonable power reserve capacity and reserve rate.

Abstract: This paper presents an effective approach for stabilizing nonlinear multiple time-delay (NMTD) interconnected systems via a composite of genetic algorithm (GA) and fuzzy controllers. First, a neural-network (NN) model is employed to approximate each subsystem with multiple time delays. Then, the dynamics of the NN model is converted into a linear differential inclusion (LDI) state-space representation. Next, in terms of Lyapunov's direct method, a delay-dependent stability criterion is derived to guarantee the exponential stability of the NMTD interconnected system. Subsequently, the stability condition of this criterion is reformulated into a linear matrix inequality (LMI). Due to the capability of GA in a random search for global optimization, the lower and upper bounds of the search space can be set so that the GA will seek better feedback gains of fuzzy controllers in order to stabilize more quickly the NMTD interconnected system based on the feedback gains via LMI-based approach. According to the Improved genetic algorithm (IGA), which is demonstrated to have better performance than that of a traditional GA, a robustness design of fuzzy control is synthesized not only to stabilize the NMTD interconnected system but also to achieve optimal H performance by minimizing the disturbance attenuation level.

Abstract: In the design of inter-satellite laser communication terminal, the diffraction effects are raised in the optical system, when we operate at the wavelength of 1550nm. This is because of the line of sight stabilization in space domain. In this paper, we designed various cassgrains which operates at aforementioned wavelength to overcome those effects. In addition, we analyzed the design as a linear beam expander to obtain a magnified beam for a long haul free space transmission. Then the beam quality is evaluated through Point Spread Function (PSF), Modulation Transfer Function (MTF), Wave front, Distortion, Energy plots & third order aberrations. Finally, we study the designs of Schmidt and Houghton type cassgrains out of which one is opted for Inter-satellite Laser communication.

Abstract: This paper proposes a wireless control system for a 3D Microscope which is designed to move in two directions - polar and azimuth angle. Both angles are controlled with electric motors based on the users joystick command and the pechan prism motor is controlled to compensate image rotation whiling moving in polar angle. Since 3D microscope can be used for arbitrary rotation in azimuth angle, wireless control system is proposed to avoid twisting of power and signal wires. The validity of our system is shown through experimental works.

Abstract: This paper proposed an efficient method based on theoretical equations to solve the dynamic interaction problem between the Timoshenko beam and maglev vehicles. A systematic PI numerical scheme is developed for the control system of the maglev train. The major advantage is that only one simple equation required in the control calculation, although the original control system is fairly complicated. Numerical simulations indicate that a large time step length can be used in the proposed method to obtain stable and accurate results.

Abstract: For the problem needed to solve during the process of steel cycle power generation, a set of pressure regulating system driven by step motor was designed based on direct-drive volume control (DDVC). An incremental fuzzy PID controller was developed for this system. Then the dynamic characteristics were simulated in Matlab/simulink. The results show that: compared with the simulation curve controlled by traditional PID, this regulating system can achieve better performance by fuzzy PID.

Abstract: Study about the performance of the service brakes and the retardation systems of commercial vehicles during the descending speed control on roads with long length steep inclination in Brazil. Mathematical models, based in the equations of the energy balance during the vehicle braking process are used. The thermal performance of the service braking system, of the engine cooling system, and of retarders, are verified for the established maximum safety speeds for a vehicle traveling downhill. The simulations are performed with programs elaborated in the Matlab-Simulink platform and with the vehicles as per the European norm ECE R13 requirements (test type II A) and the Brazilian norm requirement (NBR 10967) for the downhill functional test (test type III). The obtained results show that it is possible to have a forecast of the dissipated power in the engine and the retarder, of the capacity of dissipated heat of the radiator, and other parameters to guarantee the effective speed control of the vehicle, as per the requirements of the norms, even before the road test are performed.

Abstract: With advancement of technology, package sizes and products are becoming smaller due to miniaturization. Separate light-emitting diode (LED) chips and control integrated circuits with through silicon via (TSV) structurescan be combined to achieve reduced size. LED chipswithFlip Chip structureare capable of higher optical efficiency and heat dissipation. Analysis of LED chip structure after heat-related destruction of the chip indicated that the chip suffered stress from heating and cooling. The material used for TSV structures is copper, sincethis provides good electrical conductivity and high thermal conductivity. However, the thermal expansion coefficient of copper is higher than for other materials and can result in thermal expansion coefficient mismatch. Hence, the use of this material is likely to cause stress concentration and thus cause damage. In this study, molybdenum and tungsten were tested as replacements for copper in TSV, and the modified TSV was subjected to simulation analysis.The results indicate that replacement of TSV materials can reduce thermal expansion coefficient mismatch and consequent stress fracture and that the performance of different materials can be simulated by Fatigue Analysis and Load.