Advanced Materials Research Vols. 503-504

Abstract: The inner surface carbon in the inner grooved copper tube was determined by tube furnace heating-infrared absorption method. Some factors which influenced the determination such as sample preparation and cleaning, flow rate, furnace constants, blank value, calibration constant were tested and optimized. The inner surface carbon of copper tube was released completely while the experiment temperature was chosen as 400~600°C and the flow rate of oxygen was 750 mL/min. And the obtained integral calculus curve was ideal. The method has been applied to the determination of inner surface carbon in the inner grooved copper tube with carbon content of 0.24 mg/dm2. The result of the RSD was 3.7％. And the recovery experiment through joining in synthesize carbon sample was carried on, the recovery was 98～103%.

Abstract: For the problem of that the traditional brushless DC torque motor controller position servo system is difficult to track accurately the complex and varied location information, an improved double closed-loop controller is designed in this paper. A self-adaptive PID algorithm based on RBF neural network is employed to design position loop controller and a feed-forward control algorithm is used in the speed loop controller. The improved double closed-loop controller validated the feasibility of the new method for the design of brushless DC torque motor position servo system

Abstract: This paper applies identification technique to the marine electric propulsion system analysis, adopts the recursive extended least squares (RELS) algorithm to estimate the structure and parameters of the model, employs the variable forgetting factors into the algorithm to improve the tracking characteristic of the parameters, establishes the dynamic model of a simulated electric propulsion unit under the excitation control based on the experiment data, and finally verifies the validity of the method through the consistency between simulation result and experimental result.

Abstract: In order to enhance Electromagnetic Compatibility (EMC) of monitoring system, the EMI distribution should be obtained. But the measurement could not be accomplished perfectly because of underground condition. A novel EMI soft-sensing method was proposed to measure the electromagnetic interference(EMI) indirectly. The wavelet time-frequency analysis was introduced to monitoring system and the EMI source could be ascertained. The startup time, duration and waveform could be detected based on the running records of underground electric equipments. The electrical fast transient/burst (EFT/B), the most outstanding interference, was studied to verify the validity of wavelet analysis. EMI filter was improved in accordance of the EMI gotten from wavelet analysis. Power port immunity was developed obviously. Therefore the EFT/B of data port was restrained markedly with wavelet filtration. Coordinative effect of EMI power and wavelet filter resulted in reduction of false alarms. Results indicate that wavelet analysis and the improved EMI filter have enhanced the EMC of monitoring substations and sensors obviously. It is concluded the wavelet analysis is of guiding significance to measure underground EMI distribution and EMC of the underground monitoring system.

Abstract: According to the transmission pulse requirements of the impulse-GPR which probes the objectives of shallow soil, a transmission circuit is designed and made. On the basis of the transistor avalanche theory, avalanche transistor and RF transistor are used to generate the impulse-GPR transmission pulse as the core transistors. Trigger pulse is the square wave which is produced by FPGA as the trigger of whole system, its duty ratio under 10% and its frequency from 50 kHz to 500 kHz. As the results of simulation and actual measurement shown, single transistor avalanche circuit and four transistors cascade avalanche circuit can produce a narrow pulse with its pulse width from 1.337ns to 42.91ns. The results meet the transmission pulse requirements of impulse-GPR which probes the objectives of shallow soil.

Abstract: The hall sensor based on Hall Effect is in direct proportional to hall voltage produced under different magnetic field intensity, and the measuring probe designed according to principle of Hall Effect is used to measure the thickness of metal halide lamp arc tube quartz bulb shell. It is required to place magnetic steel ball in the bulb, the distance between the magnetic steel ball and probe is the thickness of bulb shell, which is in direct proportional to hall voltage produced by hall sensor in the magnetic field of magnetic steel ball. It is required to make use of single-chip machine, A/D converter, amplifier and others to constitute as a hardware circuit to conduct collection, data processing and value conversion for hall voltage and use LCD to show the thickness value of bulb shell.

Abstract: In order to achieve the automation of Air Traffic Control (ATC), use system to identify the controlled model of flights arrival process which has been already built, using Model Predictive Control (MPC) of the dynamic matrix contro1 (DMC) to control the ATC process. According to DMC algorithm and the features of ATC, the design parameters of this system can be determined by a lot of simulations. It proves that the system design and parameters selection make the system has the required performance and the robustness even if the parameters be changed in a wide range. The experiment on the ATC Simulation System proves that the MPC method is available, conclusion of the study provides a new idea and method for the engineering implementation of the automation of flights arrival process control and some improvement of airspace utilization.

Abstract: This paper introduces an automatic parameter measurement and analysis system of multi-phase electric machines based on Labview, presents the system hardware configuration, designs the various measuring and analysis modules, discusses the algorithm including automatic measurement, data analysis and report generation and implements the multi-channel and high-performance parallel data acquisition. Compared with the old methods, it has many advantages such as more flexible software application, higher measuring accuracy and simpler hardware configuration.

Abstract: The functions and the characteristics of RS-485 bus, I-7188 embedded controller, and SK2001 intellectual weighting controller are introduced briefly in this paper. The communication protocol of weighing controller, design of system hardware and software, and implementation of communication function are also analyzed in detail here. The serial communication between I-7188 and multiple weighing controllers has been implemented by using RS-485. As a result, the centralized control of the distributed equipments, the acquisition and automation upload of the metering data have been accomplished. The results of practical application show that this system has the characteristic of high stability and tolerance; it is easy to be managed and expanded as well.

Abstract: A robust fault detection approach for network-based system is discussed in this paper. The fault detection problem is converted into fault detection filter design. The network-induced delay is assumed to have both the upper bound and the lower bound, which is more general compared with only considering the upper bound. The Lyapunov-Krasovskii functional and the linear matrix inequality (LMI)-based procedure are adopted to design the filter. And the filter can guarantee that the estimation error satisfies the H∞ constraint. Fault detection filter is designed for a flight control system and the effectiveness is verified by the simulation results.