Applied Mechanics and Materials Vols. 128-129

Abstract: We usually adopt DSP and ARM to perform signal collection and processing. However, functions of DSP and ARM largely depend on the software. Parameter modulation of the software must account for sampling time partly. Moreover, software can not control complex peripheral logic circuit very well. The above problems render DSP and ARM containing big flaws in high-speed data collection and processing. Field-programmable Gate Array (FPGA) possesses the characteristics of timeliness, controllability and rapid processing speed. The paper designed a new circuit based on FPGA to obtain high-speed signal, and utilized FFT IP core in FPGA to perform spectral analysis with the help of digital signals from the circuit. The paper introduced the design based on FPGA and verified that it possesses good performance according to actual experiments.

Abstract: In this paper, an high altitude air-launched automatic underwater vehicles (AL-AUV) is designed based on the traditional torpedo-like AUV, REMUS. And an additional ex-range gliding wings unit is assembled on the top of AUV, which enable the AUV to be dropped at high altitude and gliding long distance to reach the signed investigating ocean field. The controllable surface on the wings also enhanced the controllability and flexibility of AUV gliding through the air and the ability against the influence of airflow interference. The AUV’s six DOF gliding model is established and a simulation system of AL-AUV is built with Matlab/Simulink. Analyzing the recorded simulation velocity and pitch characteristics of AL-AUV deployed at varying initial velocities and wing area, the optimized wing is selected.

Abstract: To aim at the characteristic of APF subject to external interference and at model uncertainty，a robust controller has been designed for the active power filter model based on the mixed sensitivity method, which is derived from control theory. We carried out several studies which have demonstrated that the controller is independent on the plant mode and the effect from the system uncertainty and disturbance can be greatly eliminated by the controller ，And thus can ensure both the internal stability and the robustness of the system. The digital simulation can prove the performance of the controller by MATLAB.

Abstract: A new sliding mode controller design approach for second-order systems is proposed that varies the switching surface in a nonlinear continuous time-varying fashion. The sliding mode control system, which the slope and intercept of switching surface changes continuously, can improve the system performance in terms of a eliminating in the reaching time process, robustness to parameters uncertainties and disturbance. The computer simulation results show the validity of the method.

Abstract: The theory of sheet model is used to design the elastic cell of pressure sensor. In this model, the elastic cell shapes like a disk; the ratio of diameter to thickness is in the range from 0.01 to 0.2. According to the calculating result, an elastic cell made by 40CrNiMo with diameter 11mm and thickness 1.6mm can test the pressure form 0 to 100MPa. It is similar with features of calculating result and works well in test.

Abstract: It is difficult to finish fully and professional testing about frequency converter sets when it was broken or repaired. Aimed at this problem, monitoring system for frequency converter sets is designed. Its hardware circuit is based on IPC platform and PCI bus and software platform is based on Visual Basic and VI (Virtual instrument) technology. It can finish controlling the work status and checking voltage, power etc. and temperature of key parts real-time about the set. Simultaneously it can give an alarm when the status is abnormal. Its results has characteristics of high reliability, high speed and intuitionistic. So it can improve efficiency of test system maximum and save repair expenditure. The system helps for improving reliability of gas turbo-generator set and power quality.

Abstract: The paper selected reasonable sensitive parameters for detecting and designed environment multi-parameters recorder with MSP430 SCM, which is the core of the recorder. It can realize to test, display, and store data in the Nonvolatile Ferroelectric Random Access Memory FM31256, even if the power of the system is shut off, the data does not lose. Utilizing Multi-parameters recorder, it can measure strength of four kinds of environment parameters, which include temperature, humidity, illumination and the concentration of carbon dioxide at the same time, and also can detect one kind parameter in four kinds of parameters. Using the interface chip CH375 which supported USB host-device mode, it can communicate with flash memory disk or PC, conveniences the using for different people in different situations.

Abstract: In this paper, we develop a transpire freight impact test system based on ASTM D6537 standard. Test object is the transportation packaging of the laptop computer in the process of drop impact test. Data acquisition are handled using low-pass filter via Matlab software, which calculated four test indicators that consist of peak acceleration, the filtered acceleration, velocity change and pulse duration. We use several drop ways, which the drop height is 40cm and 70cm, respectively. Experiments show that the test object can protect the product safety when drop height is 70cm, but the box will be broken.

Abstract: Safety, environmental protection and energy saving are three main measures of development level of modern automotive technology, where safety is in the first place. With people's living standards improvement, more and more users will choose the higher configuration, safer cars. These promote a high-performance automobile airbag system development. Ignition system is a key component of the airbag. Because of reliability, accuracy and other limitations, the existing airbag ignition system doesn’t work well. In this paper, a high-voltage piezoelectric converter used in car airbag ignition systems is discussed. It is the combination of safety and environmental protection, and improves the reliability and accuracy. The solution includes conversion circuit model of piezoelectric ignition system, frequency characteristics of piezoelectric transducer, quantum-based control technology for optimal efficiency of transformation and a starting control design of automobile airbag ignition system on piezoelectric transformer. The experiment results verify the correctness of design.

Abstract: With the constant improvement of the engine enhanced index, the crankshaft working conditions are even more critical. For designing a better dynamic performances of crankshaft, dynamic optimization design of crankshaft is researched. Boundary restrictions and dynamic loading conditions that simulate the actual ones are exerted on the finite element model of the crankshaft and its dynamic responses are calculated. Based on the sensitivity analysis method, the to-be-modified parameters are selected from the parameters which vary the dynamic properties greatly. With this method, the dynamic properties of the modified crankshaft could satisfy the design requirements, and lays a solid foundation of the dynamic optimization designing of complete engine.