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1.
密频系统的反馈控制   总被引:7,自引:2,他引:5  
孙涛  林嗣廉  徐博侯 《力学学报》1996,28(6):700-706
研究了如何将结构重频系统设计中的反馈控制律用到含有密频子结构的系统上去,主要解决了如何估计将重频系统控制律用到相应的密频系统对闭环系统的(指数)衰减律的影响,原系统的结构参数有少量变化后的新系统以及原系统是不可控的密频系统的情形.理论和数值算例表明,只要对重频系统设计的反馈律作正确的坐标变换,应用到上述三种情形时,其闭环系统的衰减律的误差只有相应频率分散度的一阶小量  相似文献   

2.
智能结构密频系统振动控制及其摄动分析   总被引:2,自引:0,他引:2  
提出一种智能结构密频控制规律的设计方法。其主要工作为:将密频子空间转化为重频子空间,把密频系统作为重频系统上的摄动;为了解决重频密频子空间相对应的特征向量选取的敏感性问题,通过摄动分析得到与重频密频子空间相对应特征向量的线性组合并利用闭环系统特征值极点配置的方法得到重频密频系统的振动规律;把所设计的振动控制规律作用于原系统和摄动系统上,讨论了结构参数改变后对系统的动态特性的影响;最后通过算例证明该方法的有效性。  相似文献   

3.
针对多飞行器协同拦截机动目标过程中的目标状态估计问题,提出了一种多飞行器对目标加速度的一致性协同估计方法。构建了多飞行器分布式协同估计结构,将扩张状态观测器和一致性理论相结合,设计了分布式协同一致性估计器。利用扩张状态观测器对目标状态进行估计,在此基础上利用一致性理论为各飞行器设计协调控制量,通过局部信息交换使得各飞行器得到一致的估计值,实现对目标加速度的精确估计。利用稳定性判定理论对一致性估计器的误差和收敛性能进行了分析,并将设计的一致性协同估计方法应用到协同拦截系统中进行了仿真验证。仿真结果显示,在不同的目标机动形式下,对目标加速度估计误差始终小于0.5 m/s~2,因此设计的一致性估计方法能够实现对目标加速度的精确估计,且具有较强的鲁棒性。  相似文献   

4.
H∞滤波及其在惯导初始对准中的应用   总被引:4,自引:2,他引:2  
阐述了H∞滤波器的设计过程,并将其运用于惯导系统的初始对准,建立了惯导系统的误差模型,并对其进行了可观性分析,利用H∞滤波方法对可观可测子系统进行了滤波计算,给出了白噪声下失准角的仿真曲线。仿真表明对准时间得到了很大的提高,精度也能够满足工程实际需要。中给出了方位误差角的一种快速估计方法,结果表明该方法是可行的。  相似文献   

5.
基于星敏感器的星载惯性基准误差的实时估计与补偿   总被引:4,自引:0,他引:4  
本文对利用星敏感器修正星载惯性基准误差的方案进行了分析并给出了仿真结果。星敏感器能够提供姿态误差观测值,以卡尔曼滤波为基础,利用这些观测值可以在线估计并补偿陀螺仪的漂移误差,从而达到保证惯性基准精度的目的。  相似文献   

6.
粒子滤波在惯导系统非线性对准中的应用   总被引:9,自引:2,他引:7  
首先介绍了粒子滤波中自举滤波的原理和算法,说明该算法可用于处理非线性系统的状态估计问题。进而列出了捷联惯导系统速度误差方程和姿态误差方程,并将其用于惯导系统非线性对准。最后,通过对仿真结果的分析,指出通过结合粒子滤波和传统的扩展卡尔曼滤波,可以得到一种精度优于卡尔曼滤波,而计算量小于粒子滤波的非线性滤波方法。  相似文献   

7.
在传统的雷达系统误差估计策略中,融合中心对雷达的观测数据进行处理,估计出系统误差并反馈给雷达对观测信息补偿误差。该策略会造成时延误差,不适于误差校准实时应用。为解决这一问题,构建了一种无需雷达观测信息和融合中心双向输入与反馈的雷达网络系统结构,提出了一种以雷达对目标状态估计信息为输入的系统误差协同估计算法。该算法采用扩展卡尔曼滤波对多雷达网络系统误差进行估计和配准。通过数学仿真,该方法对测角系统误差的估计精度达到了99%,目标的位置估计精度在系统误差补偿校正后达到96%,并且快速收敛。说明该方法能有效地估计出雷达的测角系统误差,并可直接校正和补偿雷达得到的状态估计信息,避免数据传输过程中产生的时延误差。  相似文献   

8.
研究了噪声特性和互协方差未知情况下多传感器系统的协方差交叉融合估计问题,其中噪声特性未知是指系统的状态噪声和量测噪声的相关性和真实方差均是未知的。首先,每个子系统根据最新更新时刻的测量信息,选择相应的CKF估计器,从而得到各子系统在每一时刻的一个局部估计。其次,以矩阵加权线性最小方差为最优融合准则,提出了一种快速连续的协方差交叉(SCI)融合策略,将多维优化问题简化到对几个一维非线性代价函数的优化,得到最优融合估计。再次,在子系统的估计中采用误差四元数和误差修正罗德里格斯参数相互切换的方法来避免四元数的规范约束和误差修正罗德里格斯参数奇异的发生。最后,通过一个卫星姿态估计的例子验证了所提方法的有效性。  相似文献   

9.
针对控制系统中由于测量延迟现象导致的不能直接进行状态估计问题,提出在测量方程中引入一不确定因子γ以表明系统存在测量延迟,且由γ的概率来表示系统的延迟量。同时根据U卡尔曼滤波原理,给出带有测量延迟的非线性系统的状态估计计算方法(称其为测量延迟U卡尔曼滤波算法),并将此方法应用到实际非线性测量光电跟踪系统中,与稳态卡尔曼估值器进行性能对比。仿真实验结果证明,在测量方程中引入一不确定因子γ以表明系统存在测量延迟是有效可行的,而且其性能优于卡尔曼估值器。  相似文献   

10.
组合导航系统多重衰减因子自适应估计算法比较研究   总被引:3,自引:0,他引:3  
提出了多重衰减因子自适应估计卡尔曼滤波方法,用该方法对系统每个误差状态估计进行控制,提高滤波器的估计性能。仿真结果表明,新算法在系统噪声特性不准确的情况下,能够抑制卡尔曼滤波估计的发散,GPS/SINS组合导航精度比强跟踪滤波估计的精度高。这种算法推导形式简单,计算量小,适合在线运算。  相似文献   

11.
本文提出了一种非对称矩阵特征值问题的密集模态重分析方法。它将原密集特征值问题表达为与其临近的某一重特征值问题的小摄动,从而密集模态的重分析问题就转化为重频模态的重分析问题。  相似文献   

12.
This paper addresses the problems of observer design and output feedback stabilization for a class of nonlinear multivariable systems, where the nonlinear system dynamics are described by ordinary differential equations (ODEs), and the sensor dynamics are governed by diffusion partial differential equations (PDEs). Based on the Luenberger observer theory, a Luenberger-type PDE-ODE cascaded observer is derived to estimate the state variables of the system. Then, an observer-based output feedback stabilizing controller is developed. The exponential stability of both the observer error system and closed-loop control system is proven via the Lyapunov direct method. Finally, numerical examples are provided to illustrate the effectiveness of the proposed design methods.  相似文献   

13.
In this paper, an output feedback tracking control scheme is put forwarded for a class of stochastic nonlinear systems, whose dynamics involve not only unknown parameters but also unmeasured states multiplied by output nonlinearities. A type of reduced-order observer is first developed. By adding some output related items in the observer, the estimation error realize global asymptotic convergence under disturbance free condition, and global bounded convergence when considering disturbance. Besides, the dimension of the closed-loop system is reduced, and the update law of this observer gain is beneficial for steady tracking. After the observer was established, the controller is constructed by employing the adaptive backstepping approach, and a smooth nonsingular robust item is proposed to handle the influence of stochastic disturbance. All the signals in the closed system is proved to be globally bounded in probability. Moreover the output tracking error converges to an arbitrary small neighborhood of the origin by proper choosing of the design parameters. The simulation results based on current control scheme and the comparison with the previous method illustrate that the proposed output feedback scheme realizes good tracking performance and strong ability on stochastic disturbance attenuation.  相似文献   

14.
In this paper, a new adaptive fuzzy sliding mode (AFSM) observer is proposed which can be used for a class of MIMO nonlinear systems. In the proposed algorithm, the zero-input dynamics of the plant could be unknown. In this method, a fuzzy system is designed to estimate the nonlinear behavior of the observer. The output of fuzzy rules are tuned adaptively, based on the observer error. The output connection matrix is used to combine the observer errors of individual subsystems. A robust term, which is designed based on the sliding mode theory, is added to the observer to compensate the fuzzy estimation error. The estimation error bound is adjusted by an adaptive law. The main advantage of the proposed observer is that, unlike many of the previous works, the measured outputs is not limited to the first entries of a canonical-form state vector. The proposed observer estimates the closed-loop state tracking error asymptotically, provided that the output gain matrix includes Hurwitz coefficients. The chattering is eliminated by using boundary layers around the sliding surfaces and the observer convergence is proved using a Lyapunov-based approach. The proposed method is applied on a real multilink robot manipulator. The performance of the observer shows its effectiveness in the real world.  相似文献   

15.
In this work, we present an output feedback stabilization method for the Inverted Pendulum Cart (IPC) system around its unstable equilibrium point. The pendulum is initialized in the upper-half plane, and the position of the cart and the pendulum angular positions are always available. Our strategy was accomplished introducing a suitable coordinate change to obtain a nonlinear version of the original system, which is affine in the unmeasured velocities state. This fact allows us to adapt an observer based controller devoted to render the closed-loop system to the origin. The proposed observer based controller was designed using the direct Lyapunov method. This allows estimating the corresponding attraction domain for the whole system, which can be as large or as small as desired. While the corresponding closed-loop stability analysis was made using the LaSalle Invariance Theorem. Convincing numerical simulations were included to show the performance of the closed-loop system.  相似文献   

16.
A low-complexity design problem of tracking scheme for uncertain nonholonomic mobile robots is investigated in the presence of unknown time-varying input delay. It is assumed that nonlinearities and parameters of robots and their bounds are unknown. Based on a nonlinear error transformation, a tracking control scheme ensuring preassigned bounds of overshoot, convergence rate, and steady-state values of a tracking error is firstly presented in the absence of input delay, without using any adaptive and function approximation mechanism to estimate unknown nonlinearities and model parameters and computing repeated time derivatives of certain signals. Then, we develop a low-complexity tracking scheme to deal with unknown time-varying input delay of mobile robots where some auxiliary signals and design conditions are derived for the design and stability analysis of the proposed tracking scheme. The boundedness of all signals in the closed-loop system and the guarantee of tracking performance with preassigned bounds are established through Lyapunov stability analysis. The validity of the proposed theoretical result is shown by a simulation example.  相似文献   

17.
The phenomenon of unusual turbulence intensity distributions in closely spaced rod bundles was experimentally studied. Fully developed turbulence intensities in rod-to-wall gap regions, formed by a single rod regularly mounted in a trapezoidal duct, were measured with a hot-wire anemometer. Starting from a rod setting giving a small bottom rod-to-wall gap, a series of gap spacings were achieved by moving the rod upward, resulting in larger bottom gaps and at the same time smaller top gaps. A region of high turbulence kinetic energy occurred first in the bottom gap region corresponding to the small bottom gap spacing and then shifted to the top gap region for the cases of small top gap spacings. There was no evidence of a high kinetic energy patch when the top gap size was extremely small. To unveil the mechanism behind this phenomenon, measurements on secondary velocities and energy spectra were conducted for one rod setting, and these results are described in detail. It was found that the measured secondary flow patterns could not explain the abnormal turbulence intensity distributions. However, energy density spectra revealed certain peak frequencies that support the argument that cross-gap large-scale eddy motion is of importance as both a transport process and production mechanism for subchannels formed by closely spaced rod bundles.  相似文献   

18.
In this paper, a fuzzy adaptive controller is proposed for a single-link flexible-joint robot. Fuzzy logic systems are used to approximate unknown nonlinearities, and then a fuzzy state observer is designed to estimate the immeasurable states. By combining the adaptive backstepping design with dynamic surface control (DSC) technique, a fuzzy adaptive output-feedback backstepping control approach is developed. It is proved that all the signals of the resulting closed-loop system are semiglobally uniformly ultimately bounded (SGUUB), and both the observer and tracking errors converge to a small neighborhood of the origin by appropriate choosing the design parameters. The simulation results are provided to demonstrate the effectiveness of the proposed controller. Two key advantages of our scheme are that (i)?the proposed control method does not require that the link velocity and actuator velocity of single-link flexible-joint robot be measured directly, and (ii)?the problem of ??explosion of complexity?? is avoided.  相似文献   

19.
结构优化半解析灵敏度及误差修正改进算法   总被引:1,自引:0,他引:1  
提出结构半解析灵敏度分析及其针对刚体位移的误差修正方法的改进算法, 构建灵敏度分析与误差修正项可分离形式. 该方法实现简便, 数值精度不受摄动步长与单元数目的影响. 首先从总体角度推得静力问题的误差修正半解析灵敏度分析方法, 提出了位移误差修正灵敏度列式, 并给出算法实施途径; 然后将此思路推广于自振频率、屈曲临界载荷问题, 提出了相应的计算步骤. 随后, 给出梁单元与壳单元误差修正项的具体推导方法, 并分别使用两种单元构建有限元模型进行算例测试. 结果表明, 该方法适用于多种分析类型, 数值精度不受单元数目与摄动步长的影响. 由于灵敏度分析与误差修正项可以分开计算, 该方法支持将误差修正项直接叠加于灵敏度求解结果进行误差修正, 使已有灵敏度分析程序得到充分利用. 尤其对于复杂工程结构的优化设计, 特别是形状优化设计以及尺寸、形状混合优化设计, 相比于原误差修正方法, 实现更为简便, 效率有所提升, 能为半解析灵敏度分析方法及其程序实现提供新的思路.   相似文献   

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