Advanced Materials Research Vol. 819

Abstract: Based on motion control card, it analyzed the methods and principles of the workpiece coordinate construction used the G54; created the G54 function modules, embedded CNC system of independent research and development and improved the system functions, processing efficiency and quality. The method described in the article can be directly applied to the machine tools controlled by numerical control system based on the card, and had a high practical value to the establish of other CNC machine tool workpiece coordinate system.

Abstract: Magnetic memory test technology is a new nondestructive testing technique, which is able to detect of the stress concentration area and potential fault of low speed and heavy load gear. Because the magnetic memory signals are easy to be disturbed by various sources of noises, a new method based on the intrinsic time-scale decomposition (ITD) is proposed to achieve the extraction of magnetic memory signal. Firstly, the magnetic memory signals are decomposed into several proper rotation components (PRC) and a trend component by ITD. Then reconstruct the first four order PRCs to eliminate the low frequency cyclic composition of magnetic memory signal and magnetic noise. Finally, the magnetic signal strengths of each gear tooth root are extracted using cycle average and local statistic method. The results of Experiments show that the method is suitable to pick up effective ingredients of signal to extract signal feature and has important application value in potential fault diagnosis of low speed and heavy load gearbox.

Abstract: Digital image correlation (DIC) is a kind of non-contact strain measurement method. It could provide deformation information of a specimen by processing two digital images that are captured before and after the deformation. the application of DIC method in performance testing and evaluation of new materials has great superiority over the traditional methods in the aspects that help to explore the features of new materials, such as mechanical performance, deformation mechanism and dynamic and static performance^[1-. Tensile test of 8mm steel plate based on DIC is introduced in this paper, this test is easy operated and high accuracy. It can not only get all the data that traditional method done, but also reflect the full range strain, strain history and strain rate. It can also transform the result among different type strain. The experiments based on DIC method of medium and heavy plate can help to learn the properties of material like this kind much more comprehensively, reduce testing time and promote the wide application of new material in manufacturing.

Abstract: The empirical mode decomposition (EMD) of weak signals submerged in a heavy noise was conducted and a method of stochastic resonance (SR) used for noisy EMD was presented. This method used SR as pre-treatment of EMD to remove noise and detect weak signals. The experiment result prove that this method, compared with that using EMD directly, not only improve SNR, enhance weak signals, but also improve the decomposition performance and reduce the decomposition layers.

Abstract: Attitude control in three-dimensional space for AUV (autonomous underwater vehicle) with x-shaped fins is complicated but advantageous. Yaw, pitch and roll angles of the vehicle are all associated with deflection angle of each fin while navigating underwater. In this paper, a spatial motion mathematic model of the vehicle is built by using theorem of momentum and angular momentum, and the hydrodynamic forces acting on x-shaped fins and three-blade propeller are investigated to clarify complex principle of the vehicle motion. In addition, the nonlinear dynamics equation which indicates the coupling relationship between attitude angles of vehicle and rotation angles of x-shaped fins is derived by detailed deduction. Moreover, a decoupling controller based on artificial neural networks is developed to address the coupling issue exposed in attitude control. The neural networks based controller periodically calculates and outputs deflection angles of fins according to the attitude angles measured with magnetic compass, thus the vehicles orientation can be maintained. By on-line training, twenty four weights in this controller converged according to index function.

Abstract: Proposition of a high-speed switching valve pilot control of two-cylinder two-way electro-hydraulic synchronous drive system, the establishment of a mathematical model of the system, and using fuzzy PID control strategy designed controller, at the same time building a electro-hydraulic synchronization system simulation model based on fuzzy PID controller . Simulation results show that ,when using the fuzzy PID control strategy, slave cylinder of the synchronization system follow the initiative cylinder movement well, the peak-to-average speed of the slave cylinder is 20.3mm / s. Fuzzy PID control process according to the operating conditions change error and error change, by which it has automatic adjustment of PID parameters of the synchronization system. Therefore, fuzzy PID control has better adaptive ability, and the synchronization error is 0.04 mm, achieving high synchronization accuracy. Verifying that high-speed switching valve pilot control of the synchronous drive system and its control strategy is feasible.

Abstract: In modem manufacturing,the various and complex requirement of industry makes the CNC machine tools more and more automatic and networking.While a remote monitoring and intelligent fault diagnosis system is the basic and indispensable unit for automatic and networking machine tools.This paper is focused on open CNC system,the condition monitoring, and fault diagnosis technology are researched of open CNC system. Integration achieved the CNCmachine tools' status remote monitoring and intelligent fault diagnosis, and detailed analysis of the key technologies for the components of the system. Through effectively integration of the computer technology, Fault Tree Analysis method, or other technologies to enhance the automation, networking and intelligent level of the open CNC system. Keywords: open CNC system; remote monitoring; intelligent fault diagnosis ;Fault Tree Analysis Method;

Abstract: The self-tuning fuzzy PID controller of the electro-hydraulic proportion position control system is designed and researched. Compared the self-tuning fuzzy PID control with the traditional PID control through experiments for the track effect on sinusoidal signals, the results show that the self-tuning fuzzy PID controller has higher accuracy and better stability. It is a more excellent performance controller.

Abstract: In order to realize acoustic source localization, we proposed to use microphone array and time delay based on crosscorrelation algorithm,and analyzed the factors to influence the locating accuracy, and established a realtime acoustic source localizationsystem on the NI CompactRIO system. By experiments, cross-correlation algorithm for wideband signal(sweep signal, noise signal) localization is more accurate, for narrowband signal (organ signal) localization is less significant. After analyzed factors to influence the localization accuracy, we improved sound source system, and the factors that affected the organ signal localization is verified by experiment , and improved accuracy of narrowband signal localization .

Abstract: Based on the studying of IEEE145 international standard and achievement of hardware and software of TEDS intelligent sensor, it suggested designing an intelligent unit that wont change the input / output interface of the sensor but enables device plug-and-play. The system still can operate normally when the intelligent unit was removed. The intelligent unit includes various modules or functions, such as the logo of IEEE1415 standard device, humiture measurement, nonlinear data table, unified model as well as MCU achievement, normalized treatment and synthesis of signals, aiming to realize the normalization of sensors output signals and achieve the quick connection of test system as well as plug-and-play.