Kalman滤波器在单运动目标自动跟踪中的应用

在系列帧图像中对运动目标以直方图为模型的模板方法进行匹配,由于模板匹配计算量非常大,要想在整幅图像中对目标进行搜索匹配,同时又要达到实时是不可能的。我们对目标状态进行可靠的估计,可以在相对较小的区域内完成对模板的搜索,Kalman滤波器就是一个对动态系统的状态序列进行线形最小方差估计的算法。通过以动态的状态方程和观测方程来描述系统,它可以将任意一点作为起点开始观测,采用递归滤波的方法计算。该算法具有计算量小、可实时计算的特点。     

光电检测系统的微弱信号检测研究

针对当前光电检测系统微弱信号检测存在的检测误差大、抗噪能力差等不足,设计了小波分析和最小二乘支持向量机相结合的光电检测系统微弱信号检测方法。首先采用小波分析对光电检测系统微弱信号进行处理,消除微弱信号中的噪声,抑制噪声对微弱信号检测结果的干扰,然后引入混沌分析算法对光电检测系统微弱信号进行重构,并采用最小二乘支持向量机建立光电检测系统微弱信号检测模型,最后进行了光电检测系统微弱信号检测的仿真对比测试。结果表明,本文方法可以实现高精度的光电检测系统微弱信号检测,检测速度和检测精度均优于当前其它光电检测系统微弱信号检测方法,具有更高的实际应用价值。     

Duffing振子检测微弱正弦信号的新方法

针对Duffing振子检测微弱正弦信号时,振子系统相变判别困难、计算机难以自动识别的难题,提出一种简单、利于计算机实现的相变判别方法,并根据逆向相变(由大周期状态跃迁到混沌状态)和振子阵列的原理提出一种基于Duffing振子检测微弱正弦信号的新方法,仿真分析表明,该方法对系统相变的判别准确,对微弱正弦信号检测能力强,具有工程应用潜力。     

基于简易变形蔡氏电路的混沌仿真

对变形蔡氏电路进行了稳定性分析,给出了平衡点的性质。并通过计算机仿真实验研究了系统的混沌现象和性质。仿真结果表明当初始值固定,系统参数取不同值得时候,随着参数的变化,系统的混沌吸引子也会有不同的变化。     

含-χ~5+χ~7项Duffing方程的Lyapunov指数计算

本文主要是利用非重正交化的RHR算法计算含(-χ5+χ7)项Duffing方程的Lyapunov指数,并利用四阶Runge-Kutta法求出Lyapunov指数与参数之间的变化关系,从而确定了系统由混沌状态进入周期状态的阈值。     

含-X5＋X7项Duffing方程的Lyapunov指数计算

本文主要是利用非重正交化的RHR算法计算含（-x5＋x7）项Duffing方程的Lyapunov指数,并利用四阶Runge-Kutta法求出Lyapunov指数与参数Y之间的变化关系,从而确定了系统由混沌状态进入周期状态的阈值。     

基于混沌动力学的知识创新演化规律分析

 知识创新是一个复杂的、隐含规律与秩序的演化过程,文中运用混沌理论进行了知识创新的演化趋势和规律探讨。将知识创新系统看作复杂系统,分析知识创新的混沌特性,建立基于创新能力的知识创新的混沌动力学模型。在模型建立的基础上,进行知识创新的模拟和动态演变规律的分析,以创新的状态和系统的演化为依据,将知识创新分为非时间连续的四类阶段：创新匮乏阶段、初步创新阶段、规律创新阶段和混沌创新阶段,与渐进性创新和突破性创新进行了对应分析,并基于本文的模型从知识创新角度分析了知识创新系统中渐进性创新与突破性创新的统一。     

强迫Duffing—Van der Pol振子的混沌行为

用Melnikov-Holmes方法对如下强迫Duffing-Van der Pol振子进行了分析:给出其同宿轨道的Melnikov函数及系统产生混沌的阈值.通过数值计算,运用运动轨线的直接观察,相图分析和FFT功率谱分析方法,考察系统的周期和混沌行为.并着重研究了反馈周期驱动对系统混沌行为的影响.在小参数范围内,数值结果与理论结果符合较好.本文的研究结果将为解决非线性系统的噪声干扰问题以及获得在统计分析和Monte Carlo方法中极为有用的具有给定分布的随机信号等提供途径.     

一种混沌同步系统及其在保密通信中的应用

混沌信号的非周期性连续宽带频谱,类似噪声的特性,使它具有天然的隐蔽性,因此近年来混沌同步及在保密通信中的应用受到了广泛的关注。混沌在保密通信中的应用具有强大的生命力,其关键技术是实现混沌的同步。本文论述了基于无刷式直流电机的混沌模型,同时利用状态观测器实现了发送端与接收端的同步;最后提出了基于无刷式直流电机的混沌同步保密通信系统模型,并通过仿真证明了该模型的有效性。     

爹数不确定统一混沌系统的最优控制

文章讨论了参数不确定统一混沌系统的最优控制问题。文章给出了系统的平衡点且分析了平衡点的稳定性,根据Pontryagin极小值原理为混沌系统设计一个状态反馈最优控制器,理论分析说明该控制器能将不稳定的平衡点镇定。通过对参数不确定统一混沌系统的数值模拟表明了该方法的有效性。     

Stabilization of periodic oscillations with transient delayed feedback control

Transient delayed feedback control is proposed by applying the transient control technique to the original delayed feedback control, with the aim of enlarging the stable region of the stabilized periodic oscillation, where the stable region is a subset of the parameter space of feedback gains for which the periodic oscillation is stabilized. The control signal is activated when the system is in a certain subset (the controlling area) of the state space, and inactivated otherwise, which is different from the standard control signal of the original delayed feedback control. The specific control performances of the transient delayed feedback control are investigated through case studies. The relationship between the stable region of the stabilized periodic oscillation and the controlling area is obtained by calculating the maximum Lyapunov exponent, which is a function of the feedback gain. It is shown that the stable region varies non-smoothly with the change of the controlling area. When the controlling area is properly chosen, the stable region with transient delayed feedback control is much larger than the stable region with original delayed feedback control.     

Circuit state analysis using chaotic signal excitation

A new testing method for analog circuit is proposed in this paper. A low-pass Butterworth filter is taken as the typical system under test (SUT) since the analog circuits in different types of electronic systems can be regarded as the low-, band- or high-pass active (passive) filters. The chaotic signal, which is generated by an improved Chua's circuit, is employed as the excitation signal of SUT. The SUT is a “narrowband” system compared with the bandwidth of input signal, whose state is analyzed with an error-tracking approach. The experimental result depicts that this testing method can efficiently detect the change of the circuit parameter. Besides, another eight features are extracted from the output signal of SUT for analyzing the SUT states. A discussion is made for comparing the effectiveness of each feature according to the testing results.     

基于CPLD技术的瞬态信号采集系统

冲击信号是一种瞬态信号,对其进行采集和分析需要提供完善的信号触发控制、采样频率自动设置及采样点数自动控制等功能。本文在分析了实现冲击信号采集特点及原理的基础上,研究并设计了基于CPLD(复杂可编程器件)的硬件功能模块。文中在生成系统时钟上采用了基于有限状态机的方法,完全在CPLD芯片中实现分频,取代了常见的使用8254可编程芯片的做法。此外,在模块中设计了采样频率设置、采样点数自动计点等功能,同时还可以用硬件实现多通道信号自动触发的功能,可以实现超前触发、滞后触发、电平触发、沿触发、触发电平自动设置等功能。所有的触发逻辑都使用verilog硬件描述语言在CPLD芯片中实现。通过和A/D电路配合工作,硬件模块可以实现采样的自动化。     

Probability of outlier analysis in weak GPS signal acquisition

In this paper, global positioning system (GPS) signal acquisition is investigated under weak signal conditions, when a catastrophic deterioration in performance begins to occur causing outliers to happen in range estimation. The paper compares conventional detection techniques in GPS signal acquisition. The theoretical probability of outlier is derived for GPS Gold code and compared to the probability of outlier using Monte Carlo simulation. In addition, the theoretical probability of outlier for coherent detection technique is also derived. A novel binary hypothesis test is introduced which is used to generate a new set of curves to analyze the performance of detectors in weak signal conditions.     

基于景气状态测度的国家科技创新景气指数研究——以中美日法德为例

随着区域创新系统概念成为制订区域创新政策的基础分析框架,学术界和政府加大了对区域创新指数的测度研究。但是目前的创新指数主要是基于创新能力和创新绩效的指数测度,这类指数指标之间缺乏时序性、指数的动态时效性也不足、无预警功能,指标越来越宽泛、不能反映科技创新景气状态,对科技创新政策指导性较弱。本文从景气状态的视角,基于创新周期波动的理论,提出并构建了国家科技创新景气指数,对中国等五国进行了实证研究,并构建了国家科技创新景气状态的预警信号系统。     

Sensitivity reduction in modal control systems

The conventional modal control theory is concerned with the problem of determining a state feedback matrix-valued gain which drives the system eigenvalues to prescribed positions. When the parameters of the open-loop system involve certain variations, the closed-loop eigenvalues, obtained by using a feedback gain determined as above, also contain variations. In the present paper the problem of choosing an additional state feedback gain such as to reduce the closed-loop eigenvalue variations as much as desired is solved. Specifically, upon the assumption that a nominal set of parameter values is given, and that a feedback modal control law which drives the eigenvalues of the nominal closed-loop system to the desired positions is known, two alternative expressions for the required additional reduced eigenvalue sensitivity feedback controller are derived. Both cases of known and unknown system state vector are considered. The theory is illustrated by several examples.     

Event triggered model predictive control: A less conservative result

This paper studies the event-triggered model predictive control (MPC) of a stabilizable linear continuous-time system. The optimization problem associated with the proposed MPC strategy is formulated exploiting newly designed control constraints. Compared with the conventional tube-based MPC, where the constant tightened control constraints are employed, the proposed MPC strategy exploits the time-varying control constraints, which allows the control signal to take larger values in the beginning along the prediction horizon, resulting in potentially improved system performance. The re-computation of the control signal is triggered by the deviation of the predicted system state and the real system state. Furthermore, conditions are derived based on which the design parameters can be tuned to ensure the recursive feasibility of the optimization and the stability of the closed-loop system. Finally, the effectiveness of the proposed MPC strategy is verified using a numerical example.     

大传动比减速器动力学建模及分析

重视机械结构系统的动力学问题,研究机械系统在实际工作状态下的受力变化、运动情况及其动态行为,以满足机械结构静、动态特性及低振动、低噪声的要求。因此,有必要对所设计的减速器系统进行扭振动力学分析,找到影响动态特性的薄弱环节,从而为进一步动态结构优化设计、提高减速器的动态性能提供了理论依据。     

考虑行业增长与兼容性的技术标准竞争

使用演化博弈研究方法解释技术标准演化的动态过程,预测市场均衡将会到达什么状态以及如何到达。研究结论如下:(1)技术标准的兼容性越强,产品让渡价值在竞争中的作用就越大;兼容性越弱,网络效用在竞争中的作用就越大。(2)引起市场演化的总效应可以分为增长效应与竞争效应,在市场增长阶段,增长效应起主导作用;在市场饱和阶段,竞争效应起主导作用。(3)当两种技术的让渡价值相差很大且兼容性很强时,具有较大让渡价值的技术总是抢夺竞争对手的用户,不论市场的初始状态如何,具有较大让渡价值的技术都将会占领市场。(4)当两种技术的让渡价值相差不大而兼容性较弱时,初始状态占优的技术会抢夺竞争对手的用户,初始状态的优劣由让渡价值与兼容性共同决定。     

Disturbance observer-based neural adaptive stochastic control for a class of kinetic kill vehicle subject to unmeasured states and full state constraints

This paper proposes a disturbance observer-based neural adaptive stochastic control approach for the attitude control system of a class of Kinetic Kill Vehicles (KKVs) with unmeasured states and full state constraints. First, a one-one mapping is applied to transform the attitude control system with state constraints into a nonlinear novel system without any constraint. As a result, the control objective is changed into the boundness of the novel system states. Furthermore, the disturbances existing in the system are effectively estimated and eliminated by the nonlinear disturbance observer as well as the radial basis function neural networks (RBFNNs). Moreover, due to the dynamic signal, the dynamic uncertainty induced by the unmeasured states with an unknown dynamic is compensated appropriately. Utilizing the stochastic Lyapunov process, the boundness of all the signals in the system can be proven and the state constraints are satisfied. Finally, two groups of simulations are conducted, which demonstrate the remarkable performance of the proposed algorithm under different working conditions and highlight the advantages compared with existing studies.