大功率四极管调制器的嵌入式控制设计

提出了一种大功率四极管调制器的嵌入式反馈控制系统的设计方法。该系统以DSP为控制核心,采用闭环反馈控制,开发了大功率四极管的高压端控制器,并在系统反馈信号传输中采用一种新的改进型VF光纤隔离传输方案,提高了反馈信号的传输速度。实验结果表明,该嵌入式反馈控制系统简化了HL-2A装置原有的系统,极大地提高了系统响应速度,改善了四极管输出性能,且工作可靠稳定。     

Where is the rudder of a fish？： the mechanism of swimming and control of self-propelled fish school

Numerical simulation and control of self- propelled swimming of two- and three-dimensional biomimetic fish school in a viscous flow are investigated. With a parallel computational fluid dynamics package for the two- and three-dimensional moving boundary problem, which combines the adaptive multi-grid finite volume method and the methods of immersed boundary and volume of fluid, it is found that due to the interactions of vortices in the wakes, without proper control, a fish school swim with a given flap- ping rule can not keep the fixed shape of a queue. In order to understand the secret of fish swimming, a new feedback con- trol strategy of fish motion is proposed for the first time, i,e., the locomotion speed is adjusted by the flapping frequency of the caudal, and the direction of swimming is controlled by the swinging of the head of a fish. Results show that with this feedback control strategy, a fish school can keep the good order of a queue in cruising, turning or swimming around circles. This new control strategy, which separates the speed control and direction control, is important in the construction of biomimetic robot fish, with which it greatly simplifies the control devices of a biomimetic robot fish.     

R台装置搜索两个坏硬币的一个最优过程

通过对测试集的巧妙选取,给出了用ｒ台装置搜索两个坏硬币的本性理想模型Ｂｒｅ的一个最优测试过程。     

A feedback linearization design for the control of vehicle’s lateral dynamics

In this paper, the feedback linearization scheme is applied to the control of vehicle’s lateral dynamics. Based on the assumption of constant driving speed, a second-order nonlinear lateral dynamical model is adopted for controller design. It was observed in (Liaw, D.C., Chung, W.-C. in 2006 IEEE International Conference on Systems, Man, and Cybernetics, 2006) that the saddle-node bifurcation would appear in vehicle dynamics with respect to the variation of the front wheel steering angle, which might result in spin and/or system instability. The vehicle dynamics at the saddle node bifurcation point is derived and then decomposed as an affine nominal model plus the remaining term of the overall system dynamics. Feedback linearization scheme is employed to construct the stabilizing control laws for the nominal model. The stability of the overall vehicle dynamics at the saddle-node bifurcation is then guaranteed by applying Lyapunov stability criteria. Since the remaining term of the vehicle dynamics contains the steering control input, which might change system equilibrium except the designed one. Parametric analysis of system equilibrium for an example vehicle model is also obtained to classify the regime of control gains for potential behavior of vehicle’s dynamical behavior.     

On an exact control problem for a semilinear wave equation with an unknown source

The exact controllability of a semilinear wave equation, with Dirichlet boundary control on a part of the boundary and an unknown source, is shown. The nonlinear term has at most a linear growth, the initial and target spaces are L²(Ω)×H⁻¹(Ω).     

Eliminating chaos in the Belousov–Zhabotinsky reaction by no-delay feedback and delayed feedback

We present numerical simulations of the three-variable model of the Belousov–Zhabotinsky reaction developed by Gyorgyi and Field, where chaos can occur in the free-running system. As the rate of in-flow in the continuous-flow stirred-tank reactor is controlled by the concentration of one of the reactor species through a feedback loop, we find two simple ways to bring the chaotic behavior to periodic behavior. One is to modify the feedback strength without time delay in the feedback loop, and the other is to modify the delay time of the feedback at constant feedback strength. The possible mechanisms for the two ways are discussed.     

Optimal feedback control policies for stochastic,distributed-parameter systems

This paper considers optimal feedback control policies for a class of discrete stochastic distributed-parameter systems. The class under consideration has the property that the random variable in the dynamic systems depends only on the time and possesses the Markovian property with stationary transition probabilities. A necessary condition for optimality of a feedback control policy, which has form similar to the Hamiltonian form in the deterministic case, is derived via a dynamic programming approach.     

HL－1M装置等离子体的平衡和控制

ＨＬ－１Ｍ是ＨＬ－１的改进装置，去掉铜壳后，对极向场线圈和电源都做了必要的修改。此外，还增加了四个快垂直场线圈，并采用可控环流四象限晶闸管交流器供电。对装置调试和运行结果表明．反馈控制系统能很好地维持等离子体平衡。放电一直持续到铁芯变压器的伏秒数用完为止，最长达１０４０ｍｓ。在多数放电的平顶段，等离子体位置都被控制在±４ｍｍ之内．     

基于听觉掩蔽效应的自适应反馈抵消

摘要当系统输入信号是有色信号时，传统的自适应反馈抵消算法会由于系统的输出和输入信号存在相关性而造成辨识反馈路径存在偏差，从而导致反馈抵消性能的降低。为了减小反馈路径的辨识偏差，本文提出在系统输出信号中加入被掩蔽噪声来降低系统的输入信号和输出信号的相关性的方法，噪声的能量由频域掩蔽阈值控制。这种基于听觉频域掩蔽效应的自适应反馈抵消算法改善了自适应反馈抵消的性能，同时加入的噪声是被掩蔽不可听的，输出语音的质量没有受到损害。