Advanced Materials Research Vols. 542-543

Abstract: The power average (PA) operator and power generalized mean (PGM) operator, proposed by Yager [15], are the nonlinear weighted aggregation tools whose weighting vectors depend on input arguments. In this paper, we study the power generalized mean (PGM) operator and its weighted form, and develop a power ordered weighted generalized mean (POWGM) operator, and study some properties of these operators. The relationship between the PGM operator and other existing operators is also discussed. Moreover, we utilize the weighted PGM operator to develop an approach to group decision making.

Abstract: This paper proposed a control strategy for rotor side PWM converter based on the stator voltage orientation. First, the mathematical models of Doubly-fed Induction Generator (DFIG) in a synchronous rotating coordinate system is derived .Then designed the control scheme for rotor side PWM converter. Finally, experimental platform for double-fed wind power generation system based on Infineon's XC2785 microcontrollers is established. The experimental results verify the feasibility and correctness of the control strategy.

Abstract: The paper analyzes the working principle and the advantages and disadvantages of synchronous access and asynchronous access in OPC standard. Take the traction motor performance test and control system as example. It used Visual Basic development OPC client and used PC Access as an OPC Server. The performance test bed for traction motor realize the measurement and control system efficient, stable and reliable operation. According to the characteristics of different parameters, the system chooses the methods of Subscription and Synchronous Write which used the advantages of synchronous access and asynchronous access.

Abstract: A hardware and software designing program of temperature monitoring system is proposed in this paper, which takes DS18B20 and single chip microcomputer as the core components. The system measures the real-time temperature, and supports the LCD display. The measured data is transferred to the host computer through RS232 bus. LabVIEW based PC software has data display and storage functions etc. It is verified that the system measurement error is within ±0.5°C. In the practice, the system can meet the needs of granary temperature measurement.

Abstract: The Sampling flow will be decreased because the permeability weakness of filterable membrane after the dust sampler working for a period of time. It seriously affects the accuracy of measurement, so we should keep the dust sampler working under the constant gas flow. The stable, rapidness and accuracy constant sampling can be achieved based on the application of fuzzy-PID algorithm and the adoption of PWM technique. It has carried on design to the dust sampler control system from selecting the hardware and designing the software to data processing and errors analysis, and discussing the preferable performance of the dust sample control system.

Abstract: The active disturbance rejection control (ADRC) design based on the sensitivity function is studied for the linear time-invariant SISO minimum-phase system with unknown order and uncertain relative degree. It is proved that ADRC can reject the disturbance and guarantee the close-loop stability provided that the relative degree of such plant is bounded.

Abstract: To diagnose the mechanical fault diagnosis from the rotation records, FFT and all-phase FFT (apFFT) are introduced to estimate the individual harmonics’ frequency, amplitude and phase of fault signal. Through introducing with synthesized FFT/apFFT correcting method of phase difference, the frequency and amplitude estimation can be obtained by utilizing these two spectral analysis results at the position of peak spectral line. Moreover, for apFFT possess the merit of phase invariance, the phase value at main spectral position can be directly taken as the original phase without any correcting operations, thus, waveform reconstruction is realized. Simulation experiment proves that fault information can be intuitively reflected by the quality of reconstructed waveform, and the corresponding type of mechanical fault based on parameters estimation can be identified.

Abstract: This paper applies the empirical mode decomposition (EMD) methods to gearbox vibration signal analysis capture from vibrating acceleration sensor for gearbox fault diagnosis. The original modulation fault vibration signals are firstly decomposed into a number of intrinsic mode function (IMF) by the EMD method. Then the fault information diagnosis of the gearbox vibration signals can be extracted from the coefficient-energy value of intrinsic mode function. Experiment result has shown the feasibility and efficiency of the EMD algorithms and energy characteristic method in fault diagnosis and fault message abstraction. It is significant for the monitor operating state of gearbox and detects incipient faults as soon as possible.

Abstract: Gearbox is vital components in a wide range of industrial and transport applications. It is very important how to monitor operating state of automobile gearbox and detect incipient faults. This paper applies the empirical mode decomposition (EMD) and Hilbert spectrum methods to gearbox vibration signal analysis capture from vibrating acceleration sensor for gearbox fault diagnosis. The original modulation fault vibration signals are firstly decomposed into a number of intrinsic mode function (IMF) by the EMD method. Then Hilbert spectrum of intrinsic mode function at different fault characteristic frequencies is obtained by Hilbert transform. Finally, the time-frequency fault characteristics of gearbox are analyzed by the Hilbert spectrum value of intrinsic mode function. Experiment result has shown the feasibility and efficiency of the EMD algorithms and Hilbert spectrum characteristic method in fault diagnosis and fault message abstraction.

Abstract: This paper aims at A-C axis dual rotary working table five-axis CNC system, does some research about the calculating method of space tool compensation vector in five-axis CNC machine. The algorithm of post-process of five-axis CNC machine has been analyzed. The special postprocessor based on five-axis cutter location source file(CLSF) which generated from UG NX 6.0 software has been developed and applied, and there are space tool compensation vectors in the five-axis NC code. Taking blade as machined part for example, NC code machined simulation is verified in Vericut7.0 software, and space tool compensation vector for graphic simulation is analyzed. The actual calculating results indicate that the proposed method is correct and feasible.