VCO电调特性的线性校正技术综述

VCO电调特性的线性校正技术是决定线性调频连续波雷达系统性能的关键技术之一。给出了VCO电调线性度的基本定义。VCO电调特性的线性校正技术主要包括电抗补偿线性校正、开环线性校正和闭环线性校正三种基本校正方案。详细分析了各种校正方案的基本原理,并对各种校正方案的优缺点进行了对比分析;同时,详细介绍了VCO线性校正技术的最新研究进展。     

Disturbance Attenuation in Hyperbolic 2D-systems

We consider disturbed linear 2D-systems of Fornasini–Marchesini type in the continuous time case. These systems are also named Goursat-type systems. Conditions for unique solvability of the disturbed optimal control problem with a quadratic cost functional are obtained. The disturbed or worst case optimal control guarantees to minimize the cost functional for any unknown disturbance input. In a second part then we consider a disturbance attenuation by boundary controls, i.e., by using the Goursat-data as control functions. In the 2D-case this results in two control functions acting independently on the system. We study a cooperative and a non-cooperative situation. In the cooperative situation we again obtain a disturbed optimal control problem and get conditions for existence and uniqueness of such a disturbed optimal control problem. If the action of the agents is non-cooperative we assume that it is agreed that they act on an open-loop Nash/worst-case equilibrium strategy. Sufficient conditions for the existence of such an equilibrium are obtained. Published online: April 2006     

复合控制算法在榴弹螺旋装药中的应用

榴弹螺旋装药的压药压力控制系统中,采用开环补偿控制和闭环控制结合的复合控制.开环补偿控制根据扰动量直接产生相应的补偿,以抵消其影响.而闭环反馈控制则用于克服各种干扰和对控制效果最终检验.其PID控制采用位置算法,并对控制量输出和积分增量限幅.该算法在具体的项目中得到成功的应用.     

A sliding mode control proposal for open-loop unstable processes

This papers presents a sliding mode controller based on a first-order-plus-dead-time model of the process for controlling open-loop unstable systems. The proposed controller has a simple and fixed structure with a set of tuning equations as a function of the desired performance. Both linear and nonlinear models were used to study the controller performance by computer simulations.     

Multiobjective planning of open-loop MV distribution networks using ComGIS network analysis and MOGA

An advanced method for optimal planning of open-loop medium voltage (MV) distribution network is proposed in this paper. The multiobjective planning model of open-loop MV distribution network is formulated, and an outage cost calculating method applicable for open-loop MV distribution networks is proposed. To solve the optimization problem, a special Multiobjective Genetic Algorithm (MOGA) is designed based on the network dataset built by Component Geographical Information Systems (ComGIS). The network analysis function of the ComGIS is embedded in the overall optimization process of the MOGA to find single-loop optimal paths. Crossover and mutation operator are designed according to characteristics of the coding. The evolutionary orientation is directed by the fitness function based on the Pareto order of individuals. The Pareto Optimal Set (POS) including several candidate planning schemes is obtained through the MOGA, from which the recommended scheme is selected. The practicability of the method is tested by its application to a real distribution system.     

MRAS-based sensorless control of a vector controlled five-phase induction motor drive

Multi-phase ac motor drives are nowadays considered for various applications, due to numerous advantages that they offer when compared to their three-phase counterparts. In principle, control methods for multi-phase machines are the same as for three-phase machines. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information of the rotor speed is extracted from measured stator currents and voltages at motor terminals. Vector controlled drives require estimating the magnitude and spatial orientation of the fundamental magnetic flux waves in the stator or in the rotor. Open-loop estimators and closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an open-loop and model reference adaptive system (MRAS)-based sensorless control of vector controlled five-phase induction machine with current control in the stationary reference frame. The MRAS-based sensorless operation of a three-phase induction machine is well established and the same principle is extended in this paper for an IRFOC five-phase induction machine. Performance, obtainable with hysteresis current control, is illustrated for a number of operating conditions on the basis of simulation results. Full decoupling of rotor flux control and torque control is realised. Dynamics, achievable with a five-phase vector controlled induction machine, are shown to be essentially identical to those obtainable with a three-phase induction machine. Experimental verification is also provided.     

开环式氡析出率连续测量中抽气流率的影响

应用MATLAB对开环式氡析出率测量过程中不同抽气流率下集氡罩内氡浓度随时间的变化规律进行模拟计算,并用实验对计算结果进行了验证。结果表明,在氡析出率测量时保持集氡罩参数不变的情况下,随着抽气流率的增大,集氡罩内平衡氡浓度值减小,达到平衡氡浓度的时间也缩短。实验表明,集氡罩内的平衡氡浓度的减小可最大限度地减小泄露与反扩散的影响;抽气流率的变大使集氡罩内达到平衡氡浓度时间缩短以及集氡罩内的充气均匀性愈好。通过本次实验,获得的抽气流率为1.94-3.0 L·min~(-1),集氡罩底面积为299 cm~2,体积为1.79×10~(-3)m~3。     

有源补偿器的理论分析及 PSHCE 仿真研究

该文对有源补偿器进行了理论分析和仿真研究。研究了有源补偿器的主电路构成,工作原理及其对控制系统的要求;推导出有源补偿器主电路的PSHCE模型,并对其开环系统和闭环系统进行了仿真研究,且对仿真波形进行了分析,以验证理论研究的正确性。     

Minimizing the distance to one evader while chasing another

To approach a simple game Δ² of P and E = {E₁, E₂} with no a priori evaders' role assignment and the payoff equal to the distance to one evader at an instant of catching another, we introduce a concept of casting and study the games Δ_1,2 and Δ_2,1 for preassigned and Δ_p² for open-loop casting procedures. Since Δ_p² is reduced to Δ_1,2 or Δ_2,1 which, in turn, are distinguished only by their notations, we focus attention mainly on Δ_1,2. According to the tenet of transition, Δ_1,2 is divided into a concatenation of Δ_1,2^b (basic) and Δ_1,2^a (auxiliary) games that model the problem before and after the first instant of E₁ capture. The games Δ_1,2^a, Δ_1,2^b, Δ_1,2 are studied one after another with use of the Isaacs' approach extended by Berkowitz, Breakwell, Bernhard et al.