Search

A design method of superconducting synchronous generator for wave energy conversion is proposed to obtain better output performance than the traditional permanent magnet synchronous generator. The generator has a strong magnetic field by the strong magnetic field capture ability of the superconducting bulk magnets. The output performance of superconducting synchronous generator, such as induced voltage, power density and efficiency, is superior to the permanent magnet synchronous generator. The generator model is analyzed by the finite element method to verify the correctness and rationality of the generator design.

In this paper, a design method of superconducting synchronous generator applied to wave power generation is proposed to obtain better output performance than permanent magnet synchronous generator. A strong magnetic field density is obtained by the strong magnetic field capturing ability of the superconducting material. The generator uses a fractional slot concentrated winding. By increasing the number of pole pairs, the generator can still obtain a larger electrical angle at a lower speed, thereby increasing the output voltage, which is beneficial to the improvement of the generator efficiency. The output performance of superconducting synchronous generators, such as induced voltage and efficiency, is superior to permanent magnet synchronous generators. Finite-element analysis method is applied to verify the results using Maxwell.

Structural heterogeneity in the vadose zone can significantly influence the dynamics of surface and subsurface distribution of water. It is one important reason for the patterned crops in fields. GPR as a non-invasive tool facilitates the quick investigation of subsurface structures and associated soil water contents of agricultural lands. A field study site with patterned wheat was surveyed at 1.5 m line spacing using 400 MHz multichannel GPR. Through time-lapse snapshots of the ground with multi-channel GPR and surface TDR measurements after a heavy rainfall event, we (i) determine the subsurface 3D architecture, (ii) simultaneously measure the depth-averaged soil water content, and (iii) assess the influence of the structural heterogeneity on the surface and subsurface soil water redistribution. Through investigating the field-scale soil water dynamics, we discuss the relationship between soil architecture and the patterned crops in hydrological perspective. Results demonstrate that multi-channel GPR allows the collection of valuable information about the subsurface structure and soil water dynamics at site-specific land.

In order to realize the real-time state data monitor of the electromechanical actuator(EMA), the EMA and other subsystem establish a ground half physical experiment simulation platform based on the CAN bus. The CANoe software decodes the received EMA CAN data and showes the result in the image window. The decoding data contains the EMA current, motor operation state, EMA angle and etc. Through these real-time display data, the EMA operation state could be monitored and the EMA failure could be located fastly.

In order to realize the digital of Electromechanical Actuator(EMA) control system, the CAN Bus, which has efficient reliable performance and flexible network modes, works as data interface. The EMA test scheme is designed based on the CAN Bus. First of all, the microcontroller DSP with the CAN Bus works as the core of the EMA control system circuit boards. Then the CAN Bus test network is established with the EMA, Ground Test System and Autopilot computer. The function and self-check of the EMA canbe conveniently tested by the network and the result of the test canbe easily displayed in the PC. Finally, the CAN Bus test network is established with the EMA, the Frequency Characteristics Scanner and etc. The purpose is to test the performance of the EMA. The result of the test can be intuitively showed on the Frequency Characteristics Scanner. In a word,the application of the CAN bus provides a new method to test the EMA and reference to engineering the digital EMA, which has vital significance.

In order to rapidly develop the control system code of the Electromachanical Actuator (EMA), the DSP development platform is established mostly based on the MATLAB, and the development metheod is researched. First, the DSP development platform archtecture in the environment of MATLAB is briefly introduced. And the principle of data exchange is showed. Then, the EMA hardware structure is necessarily explained, which one is for the developer to conveniently configure the system. Finally, the developer reasonably configures the DSP models used in the simulink and constitutes them to speed and position closed loop control system of the EMA, by using the RTDX and the MATLAB GUI. The EMA control system code will be debuged rapidly through this platform. The executed DSP code will be generated automatically. And the result of degugging would be showed on the MATLAB GUI. For generlly speaking, the difficulties of the EMA control system code development method is reduced and the development cycle is shortened through the MATLAB model. This system development method is fast and effective.

Under conditions of high temperature and high humidity, the moisture absorbing behavior of epoxy resin SUR-2 casting matrix for composite core was investigated, and the variation of the mechanical properties and the heat deformation temperature with hygrothermal aging were researched, The results show that the moisture-absorption behavior of the casting resin followed the Fick law. The mechanical properties and heat deformation temperature decreased with aging, but the behaviors recovered partly after drying.

In order to apply the electromechanical actuator to tactical mini-missiles, this paper researches on the key technology such as load-bearing ability, rapidity and miniaturization of the micro-electromechanical actuator power system based on the ball screw. First, according to specific technical indexes, the power, electromechanical time constant and the size of the motors are screened originally through theoretical analysis. Finally, based on the characteristics of ball screw transmission, load locus of the micro-electromechanical actuator dynamic system is theoretically analyzed and the optimum speed ratio is determined through parameter optimization. The results of the double closed loop controlled test on the principle prototype show: the system can operate normally with 2.5N·m hinge moment; the system bandwidth can reach 25.3Hz on the condition of no load and 23.4Hz on the condition of load; maximum rotational speed of output shafts is greater than 250°/s. Test results basically correspond to the requirement of technical indexes. It is proved that this analysis and design method is congruent with the design of micro-electromechanical actuators, thus the method is feasible.

A mathematical model of seeker opto-electronic platform is the basis for researching performance, designing a servo control system and simulating. Focusing on high frequencies of mechanical resonant, restriction of gimbaled axis rotation, a new model identification method was proposed under the pseudo-random invert-M-sequences. The testing signal, data acquisition, the calculating of frequency response, and least square identification were investigated. The realized steps are explicitly illustrated, and the testing example is given in this paper, the results confirm that the proposed method is effective and practical.