Applied Mechanics and Materials Vol. 389

Abstract: Valve stiction is one of the main reasons which lead to control loop oscillation.However, there is not a mature method to diagnose the stiction.Under the premise of unknown the control system model,this paper put forward a new method based on the process output signal processing to realize control valve stiction of fault diagnosis.The results of the experiment and simulation to show that the method is effective.

Abstract: The operation control of coke oven electric locomotive is an essential component of automatic control of coking manufacture. It is the main problem that coking enterprises should deal with in order to ensure the safety of production. In order to change and improve the actuality of manual driving, low positioning precision, high labor intensity and low producing efficiency, this paper proposes a practical and reliable automatic control scheme of electric locomotive based on successful experiences domestic and oversea.This scheme solves the key problem of electric locomotive automatic control-precision positioning, which containes a three-laser contraposition sensor and a positioning and lightproof piece used to ensure the accuracy of parking position detection, and a segmented deceleration control method used to ensure the automatism of parking brake. According to calculations and analysis, it is shown that the scheme could meet the system precision positioning requirements.

Abstract: The data logger is an important experimental apparatus for any experiments, even could affect the results. Unlike traditional data recorder, a modified portable data logger with advantages of high performance, small size, high storage capacity and easy use for any applications is been provided. This machine based on low power ARM cortex-m3 and no license fee BSD software, includes dual USB disk, small flash memory embedded inside machine for low range data record, a removable SD card for high range data record, a RS232 terminal for engineering function or debug, a simple controllable software filter, a small LCD and three keys as human interface for easy using.

Abstract: Considering abnormal meshing condition of converter tilting mechanism helical gear reducer,creating 3D helical gear models under normal meshing condition and abnormal meshing condition. By using the finite element method to perform a nonlinear contact analysis on helical gear, the results of gear contact stress under different meshing conditions was obtained. It provides a theoretical basis for the accurate analysis of the reasons for the failure, the optimum design and safe use of the gear.

Abstract: In this paper, the state observer design is considered for a class of nonlinear neutral delay system with nonlinear uncertainty based on Lyapunov stability theory. On condition that the nonlinear uncertain functions are gain bounded, a sufficient condition is presented for the existence of a linear feedback from interference input to control output. The less delay-dependent sufficient stability conditions for these systems in terms of linear matrix inequalities (LMI) are derived. By solving a linear matrix inequation, we can obtain the controller and observer of this system.

Abstract: A combined reverse Fourier set-up was presented on Fresnel diffraction theory. The set-up was used to measure particle size distribution with laser. A particle sample is set back of a lens. A first detector array is set in the focus plane of the lens. A second lens and a second detector array are set behind the first detector and the combined focus plane of the two lenses in turn. Thus the measurable size range at on sampling is enlarged. Experimental results on some latex samples by the prototype show that the relative errors are less than 6%.

Abstract: The effects of temperature change on the pull-in behavior and on the capacitance of the RF MEMS clamped-clamped capacitive switch are quite heavy because of the larger slenderness ratio of the MEMS clamped-clamped switch beam. A one-dimensional three-stage static model with temperature change for analyzing the beam was presented based on the small displacement assumptions, in which the clamped-clamped beam was subjected to both the electrostatic forces and the temperature change. First, the model was used to calculate the capacitance of the RF MEMS clamped-clamped capacitive switch in different states. Then , the effects of temperature change on the capacitance of the clamped-clamped capacitive switch for some different geometry dimensions were analyzed. From the analysis the effect of some geometry dimensions, such as the length of the beam, the depth of the beam and so on, at different temperature changes on the capacitance can be understood and some conclusions may be useful to the design of the MEMS clamped-clamped capacitive switch with the temperature change.

Abstract: In the fields of using green energy such as PV system and Wind power system, the step-up DC-DC converter, witch is used to convert the power, is now attracting more and more attention. The response characteristics and stability of one are key points for the performance of the whole system. However, it is complex to analyze the dynamic characteristics and control design. In this paper, the dynamic model of full-bridge DC-DC converter is presented, and transfer functions of the converter are derived by using state-space averaging method. And then the improved PI controller is designed. Finally, a laboratory prototype circuit with input voltage 220V, output voltage 600V is implemented and results are shown to confirm the validity of the designed switching device.

Abstract: Health management is the primary technical approach to ensure the safety and reliablity in aircraft. The degradation process of Mechanical Electrical and Hydraulic Integration (MEHI) systems have the characteristics of the hybrid system. In this paper, we firstly review the research on the hybrid systems in recent years, then based on the hybrid system theory , present the fault diagnosis and prediction for MEHI system in aircraft. Lastly proposes a fusion method for predicting the failure time based on the data-driven and system physical characteristics.

Abstract: Due to the nonlinearity, time-varying and load disturbance in linear servo system, the conventional PID control is hard to get an ideal control effect, this paper deduces the mathematical model of the permanent magnet linear synchronous motor (PMLSM) direct drive system, designs a fuzzy PID controller by combining fuzzy control with conventional PID control, adjust the parameters of PID controller in real time by making use of fuzzy control's ability of adjusting online. Simulation and experimental results show that the fuzzy PID controller is superior to the conventional PID controller in responsiveness, steady performance and dynamic tracking, which can shorten the positioning time, improve the system positioning accuracy.