头戴式有源噪声控制系统的分区域优化控制方法研究

本文提出了一种适用于头戴式有源噪声控制系统的有源降噪方法,结合虚拟传声器技术,并通过将水平面划分为多个子区域,实现人耳处对不同方向噪声的有效控制。初级声场传递函数的实际值与其估计值的偏差是影响头戴式有源噪声控制系统降噪量的主要因素,因此需要优化一定角度范围内的初级声场传递函数,本文提出一种基于最大化该区域最小降噪量的优化设计方法。最后,将水平面划分为不同子区域,每个子区域分别使用对应的优化初级声场传递函数进行噪声控制。实验结果验证了该噪声控制方法的有效性。      

New endless polarization control method using three fiber squeezers

In a polarization control system using two fiber squeezers of limited range, the reset causes momentary signal loss. To prevent this loss, an extra squeezer is required and a special controlling algorithm must be developed. A theoretical approach to the problem is presented resulting in such an algorithm. The presence of angular misalignment between the fiber squeezers is also discussed     

Impedance control of an active suspension system

A novel control system is developed to control dynamic behavior of a vehicle subject to road disturbances. The novelty of this paper is to apply the impedance control on an active vehicle suspension system operated by a hydraulic actuator. A relation between the passenger comfort and vehicle handling is derived using the impedance parameters. The impedance control law is simple, free of model and can be applied for a broad range of road conditions including a flat road. Impedance control is achieved through two interior loops which are force control of the actuator by feedback linearization and fuzzy control loop to track a desired body displacement provided by the impedance rule. The system stability is analyzed. A quarter-car model of suspension system and a nonlinear model of hydraulic actuator are used to simulate the control system.     

A new control system with a control delay compensation for a current-source active power filter

In this paper, a new control system for the current-source active power filter is presented. The harmonic current compensation is realized using combined feedforward control of the load currents and closed-loop control of the supply currents. The control system includes a simple method for compensating the sampling and calculation delays of the digital control system. The compensation in the proposed method is achieved using the regular LC filter of the active power filter as an energy storage for load currents, and no additional components is needed in the main circuit. Furthermore, the calculation power demand of the compensation method is very low and is, therefore, suitable for single-chip microcontroller implementations. The proposed control system is realized using a 32-bit Motorola MPC555 microcontroller. The simulation and experimental results show effective filtering performance also for higher order harmonics of the distorted load currents.     

A helmet mounted display system with active gaze control for visual telepresence

The objective of a Visual Telepresence System is to provide the operator with a high fidelity image from a remote stereo camera pair linked to a pan/tilt device such that the operator may reorient the camera position by use of head movement. Systems such as these which utilise virtual reality style helmet mounted displays have a number of limitations. The geometry of the camera positions and of the displays is generally fixed and is most suitable only for viewing elements of a scene at a particular distance. To address such limitations, a prototype system has been developed where the geometry of the displays and cameras is dynamically controlled by the eye movement of the operator. This paper explores why it is necessary to actively adjust the display system as well as the cameras and justifies the use of mechanical adjustment of the displays as an alternative to adjustment by electronic or image processing methods. The electronic and mechanical design is described including optical arrangements and control algorithms. The performance and accuracy of the system is assessed with respect to eye movement.     

Fuzzy control for active suspensions

A methodology for the design of active car suspension systems is presented. The goal is to minimize vertical car body acceleration, for passenger comfort, and to avoid hitting suspension limits, for component lifetime preservation. A controller consisting of two control loops is proposed to attain this goal. The inner loop controls a nonlinear hydraulic actuator to achieve tracking of a desired actuation force. The outer loop implements a fuzzy logic controller which interpolates linear locally optimal controllers to provide the desired actuation force. Final controller parameters are computed via genetic algorithm-based optimization. A numerical example illustrates the design methodology.     

基于高效MPC的活性污泥水处理系统控制

针对具多胞描述不确定性的污水处理控制系统,基于高效预测控制策略（EMPC）设计保性能的控制器。首先给出变参数活性污泥系统的状态空间模型,根据工况特点将其转化为多胞不确定模型,然后结合二次性能指标,通过在线求解凸规划问题,导出保证系统鲁棒渐近稳定的反馈控制律,最后以污水处理厂的处理能力为例,对设计的控制器进行仿真,结果表明,控制器能够保证系统闭环稳定,具有良好的控制效果。     

The behavior of a multiple channel active control system

The convergence behavior of an adaptive feedforward active control system is studied. This adjusts the outputs of a number of secondary sources to minimize a cost function comprising a combination of the sum of mean-square signals from a number of error sensors (the control error) and the sum of the mean-square signals fed to the secondary sources (the control effect). A steepest descent algorithm which performs this function is derived and analyzed. It is shown that some modes not only converge slowly but also require an excessive control effort for complete convergence. This ill-conditioned behavior can be controlled by the proper choice of the cost function minimized. Laboratory experiments using a 16-loudspeaker 32-microphone control system to control the harmonic sound in an enclosure are presented. The behavior of the practical system is accurately predicted from the theoretical analysis of the adaptive algorithm. The effect of errors in the assumed transfer matrix used by the steepest descent algorithm is briefly discussed     

远光灯主动预防控制系统研究

文章从远光灯滥用现象的根源着手,设计开发了一种基于红外测距激光阵的远光灯控制系统。仿真模拟的结果表明该系统优良,能准确地做出判断,并能及时给予提醒和自动切换远光灯为近光灯,达到实现远光灯的主动预防控制的目的。     

Sliding mode control for an active magnetic bearing system subject to base motion

This paper describes the application of an active magnetic bearing (AMB) system to levitate the elevation axis of an electro-optical sight mounted on a moving vehicle. In this type of system, it is desirable to retain the elevation axis in an air–gap between magnetic bearing stators while the vehicle is moving. A sliding mode control is applied to increase robustness to model uncertainties and to reduce disturbance responses. To ensure the authority of sliding mode control, model parameter uncertainties of AMB systems are analysed and reachability to sliding surface has been verified. The sliding surfaces are designed such that the poles of the closed-loop system locate at desired locations. The proposed control is applied to a 2-DOF active magnetic bearing system subject to base motion. The feasibility of the proposed technique is verified with experimental results.     

基于单周控制的电铁有源电力滤波器的研究

补偿电流的控制方法是实现有源电力滤波器功能的核心环节,本文采用单周控制的双向互补控制策略的单相有源电力滤波器能对电铁系统中的谐渡电流起到很好的补偿作用,并建立了以双向互补控制策略为补偿电流控制方法的仿真模型,仿真结果表明单用控制技术可以用于电铁供电系统的有源电力滤波器的电流控制中,并且还能有效地滤除电力机车中的绝大部分...     

Analysis and design of a multiple-loop control system for a hybrid active filter

This paper investigates the control of a hybrid active filter consisting of a single tuned resonant branch and an active element. This filter is capable of suppressing multiple harmonics using a multiple-loop control system. Linear continuous-time models are first developed in the dq reference frame. This results in a two-input/two-output system with cross coupling. The continuous model is discretized and the design of a multiple-loop discrete-time controller is examined. Wideband current feedback loops are shown to affect the coupling between the d- and q-axis controllers and provide a resistance-like damping effect. Variations in stability with processing delay times are examined. Finally, this work is extended to include narrowband harmonic specific controls. The results of the control study are confirmed by simulation and experimental results.     

一种基于系统动作的非确定不干扰模型

 本文提出一种基于系统动作的非确定不干扰模型,把不干扰关系拓展到系统动作之间,并表明信息流的产生同时依赖于发起者和观察者的动作,可通过允许发起者动作而阻止观察者动作的方法避免信息流动.最后设计了一个多级安全系统,并为排除隐蔽信道提供了一种新的方法.     

基于电子技术的主动式传感器物联网控制系统设计

针对传统主动式传感器物联网控制系统受到动态节点影响,导致其出现反应时间长、控制效果差的问题,提出了基于电子技术的主动式传感器物联网控制系统设计.通过设置控制系统和物联网之间的通信协议栈,配置外围扩展模块来构建系统的硬件结构.利用时间驱动控制节点来计算系统的反应时间,生成模糊规则矩阵,控制数据向量对应的主动式传感器执行任务,由此完成系统软件设计.实验结果表明,该系统的反应时间为0.6 s,系统输出电压变化范围为0.95～1.05 V,与实际的1.0 V电压相差较小,故系统输出电压与实际电压最为接近.     

Interfacing Software Libraries from Nondeterministic Prototypes

Modeling software systems is one of the most obvious uses of a formal specification language. A software prototype, automatically generated from the specification, enables the developer to validate the system in a real environment. However, real software systems are seldom developed from scratch, but rather built using existing libraries. In this paper, we show how a program based on existing software libraries is modeled in the Concurrent Object-Oriented Petri Net specification language, and how a prototype code is generated from the specification. In particular, we study the interface between nondeterminist synchronous prototypes and determinist asynchronous software libraries. We take into account, problems related with nonreversibility of actions and the transactional semantics of the specification language that is kept in the prototypes. A convenient delayed execution mechanism is proposed for the library linking part of the generated code.     

On the detection of load active currents for active filter control

The control of current source converters used as active filters can be based on either the current active components detection or the instantaneous imaginary power detection from which all or only a part can be used. The authors study the conditions in which this second method is equivalent to the first one and propose an improvement for the cases when it is not so     

Adaptive MIMO pole placement control for commissioning of a rotor system with active magnetic bearings

Active magnetic bearing (AMB) supported rotor systems require advanced control strategies to meet the increased performance requirements of more and more demanding applications. To meet the particular requirements for the performance under changing dynamics, an adaptive control structure is a task worth pursuing. This paper studies adaptive multi-input multi-output (MIMO) pole placement applied to the control commissioning of an AMB-supported rotor system. The control tuning approach is based on a rigid body model, and the parameter estimation is carried out with a recursive extended least squares (RELS) based algorithm for the MIMO system. The proposed approach is studied by simulations and validated with both a 2-degree-of-freedom (2-DOF) and a 4-DOF AMB system.     

A flexible active and reactive power control strategy for avariable speed constant frequency generating system

Variable-speed constant-frequency generating systems are used in wind power, hydroelectric power, aerospace, and naval power generation applications to enhance efficiency and reduce friction. In these applications, an attractive candidate is the slip power recovery system comprising a doubly excited induction machine or doubly excited brushless reluctance machine and PWM power converters with a DC link. In this paper, a flexible active and reactive power control strategy is developed, such that the optimal torque-speed profile of the turbine can be followed and overall reactive power can be controlled, while the machine copper losses have been minimized. At the same time, harmonics injected into the power network have also been minimized. In this manner, the system can function as both a highly-efficient power generator and a flexible reactive power compensator     

Rugged all-fibre endless polarisation controller

A polarisation controller comprising four lengths of PM fibre wound onto piezoelectric cylinders has been produced. It is mechanically rugged, has an insertion loss of 1.5 dB, and is capable of endless control between two arbitrary time-varying states of polarisation. Polarisation control has been successfully demonstrated for the first time in a coherent optical transmission system over installed fibre     

PCF-multimode/endless fiber sensor for respiratory rate monitoring

A respiratory monitoring system was proposed based on optical fiber. The sensor consists of photonic crystal fiber (PCF) spliced with multimode fiber (MMF) to fabricate Michelson interferometer. The sensor is inserted into an oxygen mask tube and then put on the nose and mouth to monitor the respiratory rate (RR) for different cases. The results showed that when breathing increased, the intensity of light decreased. The intensity of light in the sleeping case of breathing was more intense than that when the intensity of working sport was measured. The working sport case was a higher transmittance than that of sleeping. The sensitivity of the sensor was also measured to be 231.9 pm/RH.