Advanced Materials Research Vols. 694-697

Abstract: In the double-fed wind power system, gird voltage sags would result in some serious problems such as a fluctuation of the DC-link voltage, an instantaneous energy feedback from turbine side to grid side, which affected the steady performance of the wind power system. According to these problems, a dynamic feed forward control strategy based on the traditional feed forward control was studied, with an inhibition of above disturbances. MATLAB simulation and DSP experiments verify the effectiveness of the improved control strategy.

Abstract: With the continuous development of LED technology, LED is more and more applied to different fields such as lighting, control. In view of today's ential safety hazard brought by illegal driving, drunk driving and driver’s fatigue driving which lead to the occurrence of automobile rear-end collision and other problems, it put forward a economic, practical treatment and control system, and gave the reasonable design of intelligent vehicle control system based on LED technology and solutions. The system used SCM Atmega16 as the core, combined with LED and communication technology to realize all functions. After tested, it works well.

Abstract: In this paper, we introduce a stochastic predator-pray system with Markov switching. We establish the necessary conditions of near-optimal control for this system. The proof of the main results are based on Ito's formula, Ekeland's variational principle and some estimates on the state and the adjoint process with respect to the control variable.

Abstract: A nonlinear model of a liquid level process is obtained on the analysis of its nonlinear characteristics. Then a practical nonlinear system control strategy of the liquid level process based on single chip computer is presented. By measuring the liquid level and flow rate, two key parameters of the liquid level process, the amplification coefficient and time constant under different load are calculated. Then the control signal is calculated according to the selected control method and the automatic control of the nonlinear system is realized. The test results are given and it shows that the nonlinear control strategy is better then the linear control strategy. The nonlinear control strategy can improve control quality considerably.

Abstract: Underwater oil storage is a new offshore oil drilling technique developed in recent years. Because of the high pour point, crude oil condensation will affect its storage and transportation. In order to solve this problem, a set of thermal insulation control system for underwater oil storage was designed in this paper. Flexible isolation cloth with low thermal conductivity and insulation coatings on the inwall of oil tanks are applied to reduce temperature loss, while mamdani fuzzy controller was used to control the heating of hot water and to solve nonlinear and large time delay and inertia of the object so as to maintain the stable oil temperature.

Abstract: Chaos synchronization between two different fractional order hyperchaotic systems is presented. By using feedback controlmethod, the synchronization between two different fractional orderhyperchaotic systems is achieved based on Laplace transformation theory. Numerical simulations illustrate the effectiveness of the proposed theory.

Abstract: The variable frequency speed control is one of the most important issues for fan filter unit (FFU) system. A novel digital variable frequency control system for FFU motors were proposed and developed to decrease running losses, and improve the speed control effect and accuracy. The system uses high-performance digital signal processor (DSP) TMS320F2812 as the control core, which adopts a dedicated motor pulse width modulation (PWM) control module to achieve the FFU motors real-time online digital variable frequency control. The composition and working principle of control system were illustrated, the hardware and software design were illustrated in detail. Finally, the experimental results on control system prototype were given, which confirm the effectiveness and validity of the control strategy, and demonstrate that the proposed method can achieve accurate variable frequency speed control of FFU motors.

Abstract: The remote control system based on DTMF transmission was discussed. It used a SCM (Single-chip microcomputer) and voice chip to realize remote communication control, which voice prompts can point out and feedback state information of the controlled side for different operations. Using this method, users in the outdoor can use any a DTMF phone including mobile, fixed telephone, according to the voice prompt, to carry out remote control of the switching and timing functions of the various home appliances. The system is practical, reliable, and can be widely used in household appliances or other places of various control devices. It will be the promising future technology products.

Abstract: For a blow-off tunnel running, there is the large delay and lag issues. We build a mathematical model of the wind tunnel Mach number control by the test modeling method, then analyse the pros and cons of various control methods based on BP neural network control algorithm. Put forward genetic algorithm optimization neural network adaptive control method to solve the large inertia of the wind tunnel system, and large delay. A large number of simulation studies, run a variety of operating conditions for the wind tunnel simulation proved that the improved adaptive neural network PID control method is reasonable and effective.

Abstract: In order to against the uncertain disturbance of AC linear servo system, an H mixed sensitivity control method based on adaptive fuzzy control was putted forward in the paper. The controller is comprised of an adaptive fuzzy controller and a H robust controller, the adaptive fuzzy controller is used to approximate this ideal control law, H robust controller is designed for attenuating the approximation errors and the influence of the external disturbance. The experimental results show that this control strategy not only has a strong robustness to uncertainties of the linear system, but also has a good tracking performance, furthermore the control greatly improves the robust tracking precision of the direct drive linear servo system.