Robust stabilization of uncertain time-delay systems containing nonlinear saturating actuators

The robust stabilization problem for a class of uncertain linear time-delay systems containing sector saturating actuator is considered in this paper. The uncertain time-delay systems under consideration are described by state differential equations with time-varying unknown-but-bounded uncertain parameters and delayed state. The delay is assumed to be constant bounded but unknown. The new criterion of delay-dependent robust stabilizability for uncertain time-delay systems is presented and the corresponding robust memoryless state feedback controller is derived in terms of the solutions of several linear matrix inequalities (LMIs). Numerical example is presented to illustrate the obtained results. Project supported by the Natural Science Key Foundation of China (NSFC: 69934030) and the Excellent (Youth) Teacher for Teaching and Research Award Foundation in Institutions of China.     

影响光学读取头致动器动态特性的要素及其检测方法

光学读取头的致动器(Actuator)是光驱组件中精密定位组件,文章结合生产实际验证了改变四弦型致动器MCK模型中的要素对致动器动态特性的影响。     

Resonant frequencies of a piezoelectric drum transducer

This paper presents a piezoelectric-metal structure called a drum transducer. An equation for calculating the resonance frequency of the drum transducer is obtained based on thin plate elastic theory of piezoelectric and metal material combined with the Rayleigh-Ritz method. The finite element method （FEM） was used to predict the excitation frequency of the drum transducer. To verify the theoretical analysis, the input impedance characteristic of the drum transducer was measured using an experimental method. The results obtained from theoretical analysis were in very good agreement with those from the FEM and experimental results. The effect of geometrical changes to the thick-walled steel ring of the drum transducer at the first resonance frequency is also described. The calculated results were found to be in good agreement with the FEM results. The results indicate that the first resonance frequency of the drum decreases with the increasing inner diameter of the thick-walled steel ring.     

二杆柔性臂动力学建模与控制

用Lagrange方程对二杆柔性臂进行了动力学建模，并且研究了压电智能结构的柔性机械臂的控制，以二杆柔性臂为例讨论了压电传感器/作动器的位置、数量、尺寸以及控制增益对智能柔性臂振动控制效果的影响，可以实时、有效地控制系统的弹性振动。     

Pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer

This paper presents the construction of a pneumatic active suspension system for a one-wheel car model using fuzzy reasoning and a disturbance observer. The one-wheel car model can be approximately described as a nonlinear two degrees of freedom system subject to excitation from a road profile. The active control is composed of fuzzy and disturbance controls, and the active control force is constructed by actuating a pneumatic actuator. A phase lead-lag compensator is inserted to counter the performance degradation due to the delay of the pneumatic actuator. The experimental result indicates that the proposed active suspension improves much the vibration suppression of the car model.     

The Reissner-Sagoci problem for transversely isotropic piezoelectric half-space

INTRODUCTION In isotropic elasticity a class of mixed boundary value problems for elastic half-space can be classified as axisymmetric torsion. In this case the elastic field in cylinder components takes a particularly simple form consisting of only one nonzero displacement and two nonzero stress components. For this loading case, Reissner and Sagoci (1944) were possibly the first to examine a mixed boundary problem between the tangential displacement and stress on the half-space surface.…     

致电伸缩材料驱动智能气囊排气装置特征

本利用层叠电致伸缩驱动器设计了智能气囊排气装置，分析了其动态响应特性与缓冲驱动特性，并结合应用的需要进行了控制特性仿真。研究结果表明，该排气装置具有良好的驱动性能，可以满足智能气囊的排气控制要求。     

The 2004 Benjamin Franklin Medal in Engineering presented to Robert E. Newnham

The Franklin Institute, Philadelphia, Pennsylvania, awarded the Benjamin Franklin Medal in Engineering to Robert E. Newnham for his invention of multiphase piezoelectric transducers and their spatial architecture which revolutionized the field of acoustic imaging. The background and significance of his research is presented. Attention is focused on the impact his research prompted in the field of medical imaging, in particular non-invasive, real-time visualization of internal tissue and organs of human body using ultrasound energy. Societal impact of Dr. Newnham's work is also pointed out.     

极大望远镜基于FPGA的大批量位移促动器实时高精度控制的研究

运用现场可编程门阵列(FPGA)并发执行的特点,提出一种并行实时控制方法,其核心在于构建产生位移促动器控制信号的模块.重点介绍了如何使用底层硬件语言构建控制模块,并对它进行功能仿真.对控制系统硬件平台和软件平台的实现也做了一定介绍.     

压电材料的发展与展望

总括了压电材料的发展历程及现今的研究发展方向,简单介绍了各类压电陶瓷的特性及应用领域。详细介绍弛豫铁电单晶体、高居里温度压电陶瓷、压电复合材料,三元及多元系压电陶瓷以及无铅压电陶瓷的发展前景。