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1.
本文把一种单变量系统广义预测自适应控制的直接方法推广到多变量系统中,对其闭环稳定性和收敛性作了分析,并通过一个仿真实例表明了该算法的有效性。  相似文献   

2.
本文对一类多变量双线性系统,用修改量小二乘辨识方法,建立了自适应解耦控制逄法,分析了该算法的收敛性和稳定性。  相似文献   

3.
王平  王知人 《工程数学学报》2002,19(1):68-74,54
对无限维系统的自适应控制器的设计进行了研究,并为提高具有边界控制输出的稳定性指标的自适应控制器的设计,介绍了一个具有驱动装置的混杂系统,对运用频域特性构造的混杂系统,研究了它的初始可观性及近似可控性。  相似文献   

4.
提出了基于频域的多变量广义预测控制(MIMO-GPC)稳定性分析方法,推导了MIMO-GPC的闭环反馈结构,给出了基于闭环特征多项式的MIMO-GPC的稳定性判据和奈奎斯特稳定性判据。这些判据可作为MIMO-GPC控制器参数设计的重要依据。  相似文献   

5.
激光陀螺的工作中心频率作为激光陀螺的工作计量基准,其频率的稳定性对激光陀螺的测量精度有着直接的影响.稳定激光陀螺工作中心频率最为有效的方法就是采用主动腔长补偿控制.在对腔长控制原理和方法介绍的基础上,提出了将激光陀螺输出光强信号进行交直流分量分离独立控制的方法,并给出了系统的硬件设计框图,最后介绍了软件设计流程.测试结果表明漂移均方差在0.4°·h-1以内,满足系统的使用要求.  相似文献   

6.
赵亮  朱敏 《声学技术》2007,26(3):472-476
自适应均衡器是水声通信克服信道多径衰退、消除码间干扰(ISI)的主要手段。为了在不减少数据传输速率的情况下,有效提高系统的抗多径能力,提出了一种用于水声多载波通信系统的多通道频域自适应均衡算法。利用频域LMS算法,按照最小化频域均方误差的准则调节均衡器,从而获得最优的频域权系数。该算法一方面解决了在频域求得估计误差的问题,另一方面,和采用信道编码的方式相比,在不降低数据传输速率的情况下,有效提高了系统的性能,通过仿真试验和湖试对其性能进行了验证。  相似文献   

7.
提出了智能天线多载波CDMA系统中一种空域和频域联合的盲多用户自适应检测算法,它是将空域波束形成和频域合并检测合二为一,使得检测器在空域和频域两维上同时优化,从而提高了系统的检测性能.对这种空频联合检测算法的误码性能进行了分析,并与先自适应波束形成然后再进行频域合并的分步算法进行了仿真比较,仿真结果表明,提出的空频联合盲多用户自适应检测算法的检测性能优于分步检测算法.  相似文献   

8.
为解决车辆在真实道路中的材料摩擦异响测试精度及稳定性问题,开发车用材料摩擦异响试验台系统,基于此系统对其随机振动功率谱密度再现控制方法展开研究。采用变步长频域-X滤波LMS自适应逆控制模型来实时修正系统阻抗函数,实现功率谱密度的高精度再现。采用NI Compact RIO控制器完成数据采集及实时数据处理,对系统振动加速度进行闭环控制,从而实现功率谱密度的实时再现。试验结果表明,采用频域-X滤波LMS自适应逆控制方法可以高精度再现设定功率谱密度,再现误差小于10%,满足实际工程精度要求和实时性要求。  相似文献   

9.
基于Zarnike多项式的概念,提出了三自由度模式变形反射镜激光谐空象差的自适应校正原理,分析了系统开环传递函数和系统稳定性,闭环系统计算机模拟结果表明,该系统在频率为10Hz以下的外界相位扰动的情况下,能校正90%以上的动态象差。  相似文献   

10.
通过对有约束的Harley域自适应算法,频域自适应算法及时域自适应降噪系统的计算机仿真研究,认为在自适应通信降噪中采用基于Hartley变换的自适应算法在域自适应算法及时域自适应算法性能更优,降噪效果更好,并在高速信号处理器TMS320C30上开发实现了该算法,实验结果表明,该Hartley域适应算法应用于通信降噪系统,方法实际可行。  相似文献   

11.
Conclusions The computations and experimental investigations thus carried out show that the use of an external resonator as a frequency discriminator of a laser provides it with a low-inertia automatic frequency control system. The design developed for a high-Q optical resonator provides it with a long-term frequency stability. The application of this model in a laser automatic frequency control system serves to obtain under complex conditions a short-term laser frequency stability better than 1·10–8 and a long-term stability not worse than 4·10–8 for 15 min.  相似文献   

12.
Precision ranger for measuring large mechanical components   总被引:3,自引:0,他引:3  
Zhou ZF  Zhang T  Huang W  Guo LD  Huang J 《Applied optics》2004,43(25):4816-4820
We present a precision laser ranger system for the measurement of large manufactured components and structures. The system was developed based on a beat-wave interferometry principle. The light source of this system is a frequency-stabilized laser with a frequency stability of 1 x 10(-7) (in open air) or 10(-8) (in the laboratory). The laser operates in two longitudinal modes, and the two modes are generated in common resonator; therefore the two beams are naturally coaxial. The precision ranger system does not need a long guide or any heavy machinery. In this system an adaptive filter and a wavelet-transform program are used to improve the measurement accuracy. The system described here has a measuring range of 0-20 m and a measuring uncertainty of 30 microm/10 m.  相似文献   

13.
The spatial shaping of laser beams is a subject of research in modern optics. Recently the introduction of diffractive elements in laser resonators has offered an alternative to external beam-shaping optics by mode shaping within the resonator. We describe the specification of the laser resonator mirrors to obtain by means of internal mode shaping a desired beam outside the resonator. Modal discrimination of the modified resonator and the mirror alignment sensitivity is discussed. Basic features of resonator-originated and external beam shaping are compared.  相似文献   

14.
Optical Q factor measurements are performed on a whispering gallery mode (WGM) disk resonator using a microwave frequency domain approach instead of using an optical domain approach. An absence of hysteretic behavior and a better linearity are obtained when performing linewidth measurements by using a microwave modulation for scanning the resonances instead of the piezoelectric-based frequency tuning capability of the laser. The WGM resonator is then used to stabilize a microwave optoelectronic oscillator. The microwave output of this system generates a 12.48 GHz signal with -94 dBc/Hz phase noise at 10 kHz offset.  相似文献   

15.
高能激光与应用光学的几个问题   总被引:4,自引:0,他引:4  
高能激光的产生、传输和应用是现代激光技术和光学工程的一个重要发展方向。它不仅涉及到一系列物理问题,还有赖于多项要求极高的工程技术问题。文章提出了8个与高能激光有关的应用光学问题,包括高能激光器、高质量光学元器件、先进的自适应光学技术、非线性光学相共轭技术、变频技术及光束相干合成技术等。着重阐明对它们的要求和可能的发展方向。  相似文献   

16.
Adaptive optics and ground-to-space laser communications   总被引:1,自引:0,他引:1  
Tyson RK 《Applied optics》1996,35(19):3640-3646
The relationships between laser communication system parameters and adaptive optics system parameters are addressed. Improvement in optical signal propagation between space-based receivers and ground-based transmitters is possible with adaptive optics systems that compensate for a few degrees of freedom. Beginning with the relationship between optical signal fade and surge and the atmospheric log-amplitude variance and coupling to expressions that combine adaptive optics systems performance with the reduction in log-amplitude variance, system level examinations of the effects of adaptive optics can be done. Examples are given that show the advantageous reduction in signal fade and surge when adaptive optics are built into the optical system.  相似文献   

17.
Ellerbroek BL 《Applied optics》1997,36(36):9456-9467
Mellin transform techniques are applied to evaluate the covariance of the integrated turbulence-induced phase distortions along a pair of ray paths through the atmosphere from two points in a telescope aperture to a pair of sources at finite or infinite range. The derivation is for the case of a finite outer scale and a von Karman turbulence spectrum. The Taylor hypothesis is assumed if the two phase distortions are evaluated at two different times and amplitude scintillation effects are neglected. The resulting formula for the covariance is a power series in one variable for the case of a fixed atmospheric wind velocity profile and a power series in two variables for a fixed wind-speed profile with a random and uniformly distributed wind direction. These formulas are computationally efficient and can be easily integrated into computer codes for the numerical evaluation of adaptive optics system performance. Sample numerical results are presented to illustrate the effect of a finite outer scale on the performance of natural and laser guide star adaptive optics systems for an 8-m astronomical telescope. A hypothetical outer scale of 10 m significantly reduces the magnitude of tilt anisoplanatism, thereby improving the performance of a laser guide star adaptive optics system if the auxiliary natural star used for full-aperture tip/tilt sensing is offset from the science field. The reduction in higher-order anisoplanatism that is due to a 10-m outer scale is smaller, and the off-axis performance of a natural guide star adaptive optics system is not significantly improved.  相似文献   

18.
The quantum-cascade laser can be used as an infrared source for a small portable photoacoustic trace gas detector. The device that we describe uses a quantum-cascade laser without collimating optics mounted inside an acoustic resonator. The laser is positioned in the center of a longitudinal resonator at a pressure antinode and emits radiation along the length of the resonator exciting an axially symmetric longitudinal acoustic mode of an open-ended cylindrical resonator. Experiments are reported with an 8-microm, quasi-cw-modulated, room-temperature laser used to detect N2O.  相似文献   

19.
Pinto JF  Esterowitz L 《Applied optics》1998,37(15):3272-3275
The performance of a flash-lamp-pumped Cr:LiSAF unstable laser resonator utilizing a fourth-order super-Gaussian variable reflectivity mirror as an output coupler is described. The super-Gaussian mirror results in a smooth, flattop transverse beam profile in the near field that is advantageous for nonlinear frequency-conversion applications. Long-pulse and Q-switched operation of the Cr:LiSAF unstable laser resonator are described and compared with stable resonator operation. We obtained tunable ultraviolet radiation extending from 267 to 290 nm by frequency mixing theQ-switched Cr:LiSAF laser output with lithium triborate and beta-barium borate nonlinear crystals.  相似文献   

20.
Adaptive optics is now a standard feature for the current ultra high intensity lasers facilities. Aberration induced by both the optical components and the thermal effects in the amplification stages can be corrected with an adaptive optics system to reach both maximum peak energy and fluence. In this article, we present the development of a new technology of deformable mirror. These mirrors are designed taking into account the needs and specificities of ultra intense laser applications. They provide exceptional stability, optical quality and innovative features like scalability and maintenance of the reflective surface.  相似文献   

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