Stabilization and regulator design for a one‐dimensional unstable wave equation with input harmonic disturbance

This paper considers the parameter estimation and stabilization of a one‐dimensional wave equation with instability suffered at one end and uncertainty of harmonic disturbance at the controlled end. The backstepping method for infinite‐dimensional system is adopted in the design of the adaptive regulator. It is shown that the resulting closed‐loop system is asymptotically stable. Meanwhile, the estimated parameter is shown to be convergent to the unknown parameter as time goes to infinity. Copyright © 2011 John Wiley & Sons, Ltd.     

Parameter estimation and stabilization for a wave equation with boundary output harmonic disturbance and non‐collocated control

This paper is concerned with the parameter estimation and stabilization of a one‐dimensional wave equation with harmonic disturbance suffered by boundary observation at one end and the non‐collocated control at the other end. An adaptive observer is designed in terms of measured velocity corrupted by harmonic disturbance with unknown magnitude. The backstepping method for infinite‐dimensional system is adopted in the design of the feedback law. It is shown that the resulting closed‐loop system is asymptotically stable. Meanwhile, the estimated parameter is shown to be convergent to the unknown parameter as time goes to infinity. Copyright © 2010 John Wiley & Sons, Ltd.     

蚁群算法在系统辨识中的应用

将传统用于离散空间问题求解的蚁群算法引入连续空间内的系统参数辨识问题求解, 定义了各智能单蚁的信息量分布函数和相应的系统辨识求解算法,并在线性系统参数辨识的实 例仿真中得到了很好的结果,显示了蚁群算法在连续空间优化问题中的应用前景.最后,对蚁群 算法在连续空间优化领域中的适用特征作了总结,并指出了今后进一步工作的方向.     

自检式冲击波参量检测系统设计

针对冲击波参量检测与系统可靠性问题,设计了一种带自检功能的冲击波参量检测系统。传感头采用自发光式光纤镀膜探针,光纤探针在冲击高压下发光,并通过高速光电转换与示波器记录冲击响应信号,实现对冲击波参量检测。将激光脉冲耦合入传感光路,通过检测激光脉冲在镀膜光纤探针端面镀膜层的反射脉冲信号实现系统自检。详细介绍了镀膜光纤探针、高速光电转换电路及半导体激光器脉冲驱动源的设计与实现。进行了TNT爆轰驱动条件下冲击波到达时间的测量,实验结果表明：整系统的冲击波响应信号前沿小于5ns,测量不确定度小于3ns,为爆轰物理和冲击波物理实验中冲击波参量检测提供了一种可靠有效的测试手段。     

Adaptive model predictive control for a class of constrained linear systems based on the comparison model

This paper proposes an adaptive model predictive control (MPC) algorithm for a class of constrained linear systems, which estimates system parameters on-line and produces the control input satisfying input/state constraints for possible parameter estimation errors. The key idea is to combine the robust MPC method based on the comparison model with an adaptive parameter estimation method suitable for MPC. To this end, first, a new parameter update method based on the moving horizon estimation is proposed, which allows to predict an estimation error bound over the prediction horizon. Second, an adaptive MPC algorithm is developed by combining the on-line parameter estimation with an MPC method based on the comparison model, suitably modified to cope with the time-varying case. This method guarantees feasibility and stability of the closed-loop system in the presence of state/input constraints. A numerical example is given to demonstrate its effectiveness.     

Robust space time processing based on bi-iterative scheme of secondary data selection and PSWF method

Prolate spheroidal wave function (PSWF) method could improve the target detection performance for space-time adaptive processing (STAP) in nonhomogeneous environment. However, it may be ineffective with system parameter error. In this paper, we correct the system parameter with clutter spectrum analysis. Since contaminated samples contained in the secondary data set have detrimental impact on this spectrum analysis, the traditional sample selection method of generalized inner production (GIP) is combined with PSWF method, and then a bi-iterative scheme is proposed. Firstly, the system parameter for PSWF is estimated via the analysis of spectrum image, which is constructed with the secondary data set. Then, the covariance matrix is derived by PSWF method with the estimated parameter. Thirdly, the GIP sample selection technique is implemented with the PSWF covariance matrix, and the secondary data set would be updated. Repeat these steps until a stable parameter is obtained. Several vital issues such as how to estimate the parameter with real data and why the precision of covariance matrix could be improved during the iteration are analyzed. In the end, the validity of the proposed algorithm is substantiated by practical and simulation results.     

基于反馈教学优化算法的混沌系统参数辨识

针对传统智能优化算法对混沌系统参数辨识精度低、速度慢的问题,提出一种基于反馈教学优化算法的混沌系统参数辨识的新方法.该方法以教学优化算法为基础,在教授-学习阶段之后加入反馈阶段,同时将参数辨识问题转化为参数空间上的函数优化问题.分别以三维二次自治广义Lorenz系统、Jerk系统和Sprott-J系统为待辨识模型,对粒子群优化算法、量子粒子群优化算法、教学优化算法及反馈教学优化算法进行了对比实验,反馈教学优化算法辨识误差为零,搜索次数明显减少.仿真结果表明,反馈教学优化算法明显提高了混沌系统参数辨识精度和速度,验证了该算法的可行性和有效性.     

基于BES7456芯片的OSD的应用平台设计

重点介绍了北京市嵌入式系统重点实验室自主研发的OSD产生芯片BES7456的组成和原理,并给出应用该芯片的具体方法和实现效果.阐述了OSD原理及芯片设计的原理,接着给出根据具体要求需要的外围设计方案,给出了系统软硬件的设计步骤,最后给出实测结果.     

基于模糊规则的非线性系统建模方法

提出了一种基于模糊聚类自调整的模糊建模方法,基于模糊聚类通过自适应模糊推理来调整模糊系统,一种在线辨识算法的是通过非线笥系统参数的在线性估计来进行的,为了证明了所提出方法的适用性,给出了几个实例的仿真结果。     

D-P算法的改进及其在飞行轨迹回放中的应用

飞行参数记录了飞行器飞过的位置、姿态和飞行状态,飞行结束后,对飞行参数进行可视化回放,无论是实际的飞行训练中,还是飞行仿真中都是必不可少的,但在回放时,如果逐点显示这些数据,将会消耗大量的系统资源.本文提出一种基于限定俯仰角和航向角变化率的道格拉斯—普克(Douglas-Poiker,D-P)压缩算法对将要显示的轨迹点进行压缩,并对算法进行了验证,效果良好.     

基于DSP的机器人末端力控制系统设计

工业机器人的运动分为自由运动和受力约束运动两种不同的运动类型;受力约束运动不仅要进行精确的位置控制,而且要对接触力进行精确控制;文章对机械臂的末端力控制系统进行了研究;采用了高精度电动滑台作为力控制系统的执行机构,在电动滑台末端增加了柔性单元,从而克服了系统柔性不足的缺点,并且依据Lyapunov稳定性理论确定系统的二阶参数,使用Narendra提出的稳定自适应设计方法构建了电动滑台的数学模型;对机械臂末端柔顺系统的系统设计及算法进行了研究,消除了外界噪声对系统的干扰,解决了力控制的基本控制策略问题,优化了力控制时系统的响应特性。     

网络拥塞控制的稳定性研究

针对网络拥塞控制存在的系统参数设置反应过于敏感造成的系统稳定性差的问题,建立时滞反馈控制模型,找出反馈控制中参数之间的联系,确定系统稳定性的条件。通过对主动队列管理三种算法的仿真实验,证明:RED算法在满足稳定性条件后,网络的性能有了很大改善,获得了较满意的效果。     

汽车发动机与传动系优化匹配的仿真研究

如何设计传动系参数以达到与汽车发动机的合理匹配是汽车设计中一个重要的组成部分.文中以汽车主减速比和各档传动比为设计变量,综合汽车动力性评价指标和经济性评价指标作为目标函数,建立了优化模型,应用优化规划理论对汽车传动系参数进行优化设计,开发出了一套汽车传动系参数优化设计的仿真软件,实现了汽车发动机与传动系的最佳匹配.文章最后以某载货汽车为例,利用该优化仿真软件进行了设计计算,仿真结果表明,该设计方法是可行的.     

ENVISAT-1 ASAR成像系统的设计和实现

针对ENVISAT-1卫星,研究了ASAR数据成像关键算法,给出一种提高系统多普勒估计稳定性的渐进策略。文章详细论述了系统的设计和实现方法,并给出了成像系统的实际处理结果。     

单相PWM整流器电压环的优化设计与仿真

为了改进单相电压型脉宽调制（PWM）整流器电压环的动态设计,提出了1种双零点典型Ⅱ型系统设计法,用于该整流器系统电压外环的调节器结构与参数优化设计,以取代目前广泛采用的典型Ⅱ型系统设计法。然后对按照这2种不同方法设计的系统进行了Simulink建模和仿真。仿真结果表明,采用提出的新方法设计的整流器系统时域性能指标更好。     

非线性混沌时序预测研究及应用

混沌是一种普遍存在的非线性动力学行为，针对混沌时间序列的难以预测和控制的问题，提出了基于趋势的混沌预测模型，利用混沌系统的初值、参数敏感性来微调和控制系统扰动。并用改进的最优化方法来估计模型的参数，在其相空间中对时序的未来值进行预测，算例表明。选取最佳的模型阶数能增加预测的准确程度，它不仅克服了仅用延迟嵌入技术的弊端，也降低了直接使用预测误差决定输入模式的盲目性．预测效果比其它时序方法要好．     

生化分离用离子交换填料评估系统

填料评估是填料选择的前提。本文从制备色谱实际出发，以产率为最终目标，讨论了影响目标的主要因素，构建了评估预选指标集，在此基础上，根据实际获取数据的可能性，设计了综合评估系统，并介绍了系统的特点，评估系统已由Ｖｉｓｕａｌ Ｂａｓｉｃ５程序化。     

基于Linux的代理服务器的设计与实现

论述了Linux平台上的代理服务器的设计与实现过程。介绍了代理服务器的工作原理,并对其参数设置、安全性、日志分析和计费系统分别进行了探讨,最后给出了代理服务器的流量监测方法。     

Inverse cartesian trajectory control and stabilization of a three-axis flexible manipulator

This article treats the question of end point trajectory control of a flexible manipulator based on the nonlinear inversion technique. The manipulator has two rigid links and the third link is elastic. A parameterization of the Cartesian coordinates of a point close to the end effector position is suggested. Using these coordinates as output variables, an inverse feedback control law is derived for tracking reference Cartesian trajectories. The stability of the zero dynamics associated with the end point motion control is examined. It is shown that inverse control of the end point causes divergent oscillatory flexible modes. In addition, for regulating the end point to a fixed position, a linear stabilizer is designed to damp the elastic vibration. Simulation results are presented to show that in the closed-loop system, reference end point trajectories can be accurately followed in spite of the parameter uncertainty in the arm dynamic model. © 1994 John Wiley & Sons, Inc.     

Trajectory Tracking Control of an Underactuated Underwater Vehicle Redundant Manipulator System

The purpose of this study is to control the position of an underactuated underwater vehicle manipulator system (U‐UVMS). It is possible to control the end‐effector using a regular 6‐DOF manipulator despite the undesired displacements of the underactuated vehicle within a certain range. However, in this study an 8‐DOF redundant manipulator is used in order to increase the positioning accuracy of the end‐effector. The redundancy is resolved according to the criterion of minimal vehicle and joint motions. The underactuated underwater vehicle redundant manipulator system is modeled including the hydrodynamic forces for the manipulator in addition to those for the autonomous underwater vehicle (AUV). The shadowing effects of the bodies on each other are also taken into account when computing the hydrodynamic forces. The Newton‐Euler formulation is used to derive the system equations of motion including the thruster dynamics. In order to establish the end‐effector trajectory tracking control of the system, an inverse dynamics control law is formulated. The effectiveness of the control law even in the presence of parameter uncertainties and disturbing ocean currents is illustrated by simulations.