QFT application for headphone's active noise cancellation

A quantitative feedback theory design for attenuation of acoustic noise in earphones and headphones is described. Identification including uncertainty is measured for several ears and device location in the ear neighbourhood. Theoretical limitations are discussed. Copyright © 2002 John Wiley & Sons, Ltd.     

QFT design of multi‐loop nonlinear control systems

In control practice, one of the fundamental limitations of feedback is given by the sensor noise effect. This problem is still more important in uncertain nonlinear control systems. This work extends the previous multi‐loop QFT technique, specifically designed to accommodate bandwidth limitation, to the nonlinear case. Copyright © 2000 John Wiley & Sons, Ltd.     

Multi-input,multi-output flight control system design for the YF-16 using nonlinear QFT and pilot compensation

Nonlinear quantitative feedback theory (QFT) and pilot compensation techniques are used to design a 2 × 2 flight control system for the YF-16 aircraft over a large range of plant uncertainty. The design is based on numerical input-output time histories generated with a FORTRAN implemented nonlinear simulation of the YF-16. The first step of the design process is the generation of a set of equivalent linear time-invariant (LTI) plant models to represent the actual nonlinear plant. It has been proven that the solution to the equivalent plant problem is guaranteed to solve the original nonlinear problem. Standard QFT techniques are then used in the design synthesis based on the equivalent plant models. A detailed mathematical development of the method used to develop these equivalent LTI plant models is provided. After this inner-loop design, pilot compensation is developed to reduce the pilot's workload. This outer-loop design is also based on a set of equivalent LTI plant models. This is accomplished by modelling the pilot with parameters that result in good handling qualities ratings, and developing the necessary compensation to force the desired system responses.     

Pre‐filter design for tracking error specifications in QFT

This note shows how the pre‐filter may be designed in quantitative feedback design of single‐input, single‐output systems with tracking error specifications (Eitelberg, Automatica, 2000; 36(2):319). The method uses gain and phase information for the pre‐filter design. The design is conveniently performed on the log polar complex plane using standard CAD tools. Copyright © 2003 John Wiley & Sons, Ltd.     

QFT在高速线性电机直接驱动平面运动定位控制系统中的应用

研究定量反馈理论(QFT)在高速直线电机直接驱动平面运动定位系统控制中的应用问题.该系统采用三闭环(即电流,速度,位置)串级反馈控制加前馈补偿结构.基于8台不同机器上实际测得的频域特性,所设计的QFT高阶鲁棒控制器可以大大降低该系统在大加速度运动状态下所呈现的谐振不确定性.同时,该控制器对传感器噪声和干扰也具有较好的抑制能力.在最大加速度达到6.8g的给定运动轨迹条件下,通过在批量生产的打线机(用于半导体封装)平面运动定位系统的实验结果证实了该方法的有效性.     

弹性飞机的QFT控制器设计

以某弹性飞机纵向模型为例,考虑模型的不确定性及外部扰动,应用定量反馈理论设计了其俯仰姿态保持系统.仿真结果表明,利用该理论方法设计的控制器能很好地抑制弹性飞机的结构弹性变形,具有良好的鲁棒性,并取得了满意的控制效果,证明了该方法在弹性飞机控制律设计中的有效性和实用性.     

压电定位系统的自抗扰控制设计

纳米定位系统中广泛采用的压电驱动器因存在非线性、多映射的迟滞特性而严重影响了纳米定位系统的定位精度.为消除迟滞对定位精度的影响,将其视为干扰,设计不基于迟滞及定位系统精确数学模型的自抗扰控制算法,利用扩张状态观测器实时估计迟滞,进而补偿其对定位精度的影响,获得了良好的定化系统控制仿真效果.仿真结果表明,自抗扰控制器能够仃效消除迟滞、提高纳米定位系统的定位精度.     

Globally linearized control system design of a constrained multivariable distillation column

The goal of this paper is to develop a discrete-time multivariable globally linearized control (GLC) algorithm, which provides low computational requirements with constraint handling ability. The control strategy is constructed with four elements: a transformer that accounts for process nonlinearities; an estimator, which observes the required unmeasured states; a variable constraint mapping optimizer that transforms the input constraints of the nonlinear process into constraints on the manipulated inputs of the globally linearized system and a quadratic dynamic matrix controller (QDMC) that provides constraints handling ability. The effectiveness of the designed controller has been tested on a multi-input multi-output (MIMO) nonlinear distillation column through extensive numerical simulations. The control law showed a high quality performance for set point tracking and disturbance rejection in presence of parametric uncertainty. The effect of unmeasured disturbance also has been studied through the simulation experiment. In the comparative study, the proposed GLC-QDMC control technique outperformed the GLC-DMC control law.     

基于反馈线性化控制的航空气动伺服系统

提出了一种非线性跟踪控制器的设计方法并应用在某型号航空气动伺服系统中.由于该系统的连接孔和伺服阀组成了一个双约束子系统,因此其气缸内腔压力很难控制.设计了一个改进的反馈线性化控制器用来消除双约束造成的奇点,线性矩阵不等式方法用于确保跟踪误差的稳定性,仿真结果表明该控制器具有良好的动态特性及抗干扰能力.     

气动位置伺服系统的非对称模糊PID控制

对于有杆气缸的非对称物理及摩擦力特性,提出了采用非对称模糊策略的模糊PID控制算法,较好地解决了有杆气缸由于左右两腔物理结构和摩擦力特性的不对称而造成运动过程中压力变化复杂的问题,改善了系统的动态响应性能.实验证明,采用非对称模糊策略的模糊PID控制可以明显地提高气动位置伺服系统的动态响应性能,系统具有较小的超调量和过渡过程时间,并获得了满意的重复稳态精度.     

微小气动机器人系统的模糊自适应PID控制

基于尺蠖的移动机理,研制了一种具有柔性移动机构的微小气动机器人内窥镜诊疗系统。描述了微机器人系统的本体结构和运动机理,并通过分析机器人系统的驱动力学特性和机器人的移动控制特性,给出了基于模糊自适应PID的气压-位置伺服控制方法,计算机仿真实验结果表明基于模糊自适应PID算法可实现机器人系统的有效控制。     

Robust dynamic ship positioning control system design and applications

This paper describes the robust control system design for a ship dynamic positioning system. The control design is based on an approximate linear model derived from the nonlinear hydrodynamic equations governing the horizontal motions of the ship. The nonlinear models of the ship, seawaves, current, wind and thrusters are derived and simulated for control design verification. The H_∞ control design technique is employed to design the controller. The control problem is formulated in state‐space form and the design specifications are translated into requirements on the weighting functions of the error signal and the thrusters input. A tuning procedure is proposed based on the wind and wave disturbances. The controller is initially tested on the nonlinear ship model and simulation results are presented to demonstrate the robustness of the H_∞ controller. Tank tests results are then presented to assess the controller performance. Copyright © 2001 John Wiley & Sons, Ltd.     

Adaptive positioning control of an ultrasonic linear motor system

A 3PRR parallel precision positioning system, driven by three ultrasonic linear motors, was designed for use as the object stage of a scanning electron microscope (SEM). To improve the tracking accuracy of the parallel platform, the positioning control algorithms for the drive joints needed to be studied. The dead-zone phenomenon caused by static friction reduces the trajectory tracking accuracy significantly. Linear control algorithms such as PID (Proportion Integration Differentiation) are unable to compensate effectively for the dead-zone nonlinearity. To address this problem, two types of feedforward compensation control algorithms have been investigated. One is constant feedforward with the integral separation PID; the other is adaptive feedback and feedforward based on the model reference adaptive control (MRAC). Simulations and experiments were conducted using these two control algorithms. The results demonstrated that the constant feedforward with integral separation PID algorithm can compensate for the time-invariant system after identifying the dead-zone depth, while the adaptive feedback and feedforward algorithm is more suitable for the time-varying system. The experimental results show good agreement with the simulation results for these two control algorithms. For the dead-zone nonlinearity caused by the static friction, the adaptive feedback and feedforward algorithm can effectively improve the trajectory tracking accuracy.     

气动垃圾回收系统阀门控制策略研究

为实现气动垃圾回收系统的实际应用,阀门控制策略方案的设计与验证十分重要。分析系统运行过程,抽象出系统运行参数并建立数学模型,确定系统“自下而上”的基本控制逻辑。设计分析了以单层循环式排空策略为代表的三种控制方案,确定单元式阀门控制为最优选择,并以数值模拟的方式对研究内容进行了验证。该方案使得系统执行排空动作时阀门开启次数较少,系统设备成本降低,安全性提高。     

考虑事件触发输入的船舶自适应动力定位控制

为解决实际海况下全驱动船舶的动力定位控制任务存在参数不确定、模型结构不确定和通信资源限制等问题,本文提出一种具有事件触发输入的鲁棒自适应动力定位控制算法.该算法采用径向基函数神经网络对系统模型不确定进行逼近,同时针对通信带宽受限问题,设计了一种具有事件触发机制的执行器输入,降低了控制器和执行器之间的信道占用.此外,该算法还解决了状态变量与执行器增益不确定性之间的强耦合问题,并且设计了在线更新的自适应参数去补偿执行器增益不确定,以确保船舶能够稳定执行动力定位任务.利用Lyapunov稳定性理论证明了闭环控制系统中所有误差变量都满足半全局一致最终有界收敛.通过对比仿真实验验证了所提出算法的有效性.     

Robust adaptive fault‐tolerant control of dynamic positioning vessel with position reference system faults using backstepping design

This paper presents a solution to guarantee a fault‐tolerant control (FTC) of dynamic positioning (DP) vessel in the presence of the position reference system (PRS) faults by using the backstepping technique. The faults modes of PRS are modeled as an additive uncertainty in the feedback loop of the DP control system, and the bounds of the additive uncertainty are unknown. Through estimating online the unknown bounds on the basis of the designed adaptive mechanism, the robust adaptive fault‐tolerant controller (RAFTC), which takes the faulty PRS measurements as the inputs, is proposed rather than detecting and isolating them. Moreover, the developed RAFTC is proved by applying Lyapunov stability theory that the closed‐loop DP control system is uniformly bounded and the tracking error can be converged to zero asymptotically despite of the PRS failures. A simulation scenario on an offshore supply vessel model is provided to validate the effectiveness of the designed RAFTC, and the results show that the RAFTC has better performance and robustness compared with the ordinary fine‐tuned adaptive backstepping controller.     

UWB定位系统FPGA基带处理设计

基于到达时间差(TDOA)算法,设计了一个脉冲超宽带(IR-UWB)室内定位系统的原理验证样机。主要介绍传感器捕捉标签发送的IR-UWB窄脉冲,进而测出窄脉冲到达传感器时刻的方法。利用FPGA中数字时钟管理器(DCM)的相移器功能模块(PS)构成延迟锁相环(DLL),测得到达传感器的窄脉冲相对于同步时钟的时刻。原理验证系统定位精度优于40cm,达到设计要求。     

磁悬浮微驱动器的定位控制系统设计

针对磁场同步跟随式磁悬浮微驱动器,构建了新型的集驱动、测量和控制于一体的磁悬浮微驱动器定位系统。设计了一套以DSP为核心的硬件控制板的运行软件。采用LabVIEW软件实现了上位机的数据采集、显示、分析及保存等功能。以(1.231,1.227)mm、(1.529,1.516)mm两点为目标进行了定位实验。实验结果证明这种定位控制系统的误差在0.001~0.009 mm之间,该定位控制系统具有较好的控制精度。     

具有输入延时的锚泊自动定位系统保性能控制

从半潜式平台定位系统的经济性及安全性角度出发,提出基于锚链切换控制的自动锚泊定位系统新方案.针对方案中具有输入延时及不确定性的特点,设计了带有输入延时的保性能控制器,以产生抵抗环境扰动所需的控制输入.基于LMI方法给出控制器存在的充分条件,通过求解相应的线性矩阵不等式得到系统的保性能控制律.仿真结果表明,所设计的控制器能有效解决锚泊自动定位系统的参数不确定性及输入延时问题,从而提高系统的精度和性能.