【作者】 邵敏强；

【导师】 陈卫东；

【作者基本信息】 南京航空航天大学 ， 工程力学， 2012， 博士

【摘要】 复杂激励作用下的振动控制涉及到结构动力学，控制理论，信号处理，计算机应用等多个交叉学科领域。分布式结构在复杂激励作用下具有复杂的动力学行为，长期以来一直吸引着广大学者的关注。复杂激励会使这类结构产生分叉、混沌等非线性动力学行为。由于这类受控结构具有连续性特点，拥有无穷维数，对其进行理论分析具有相当大的困难。另外，通过计算机或DSP等硬件设施进行控制器设计时，容易引起观测和控制溢出的问题，从而导致系统失稳，这对控制算法的鲁棒性和抗干扰性能提出了更高的要求。因此，研究复杂激励作用下分布式结构的控制问题具有极大的挑战性，同时具有很强的工程应用背景和科学意义。本文以风洞测力模型受跨声速风载作用下的振动控制为背景，研究分布式结构受复杂激励作用下的系统动力学控制问题。论文的主要研究内容和学术贡献如下：1.针对模型参数已知的受控对象，进行输入估计控制方法的研究。为提高系统控制效果，得到更为可靠的控制输入，将未知外扰引入到控制器的设计和求解过程中。研究表明，结合随机游走模型能够将系统转换为不显含系统外扰的状态方程。针对该新方程进行Kalman滤波估计得到系统状态，其中包含未知外扰的估计值。因此，就可以采用线性二次型Gauss方法得到含外扰的控制器表达式。2.研究了滤波器时滞对受控系统稳定性的影响。为消除分布式受控系统输出信号中的高频和噪声干扰，引入抗混滤波器和高阶低通数字滤波器作为信号处理手段。不考虑滤波器过渡带非线性相频的影响，将通带范围内的相频特性近似成线性关系，研究滤波器产生的固定时滞现象。并进一步分析该时滞对控制系统动力学的影响，通过分析得到系统稳定时滞区域。3.研究了系统存在输出时滞情况下的控制方法，提出基于时滞利用和消除的控制器设计方法。在时滞利用方面，根据系统稳定时滞区域内的脉冲响应衰减速度，确定接近最佳控制效果时的时滞量，以此为依据对系统时滞重新设定以提升控制效果。另外，在时滞消除控制方法的研究方面，建立了不显含时滞的离散状态方程，结合LQ控制方法实现基于固定时滞的振动主动控制研究。4.考虑滤波器过渡带非线性相频特性，研究由此产生的可变时滞现象。在处理这一问题过程中采用相位补偿法将原本含有可变时滞的系统转换为固定时滞系统，为进一步研究消除总体时滞建立可靠的输出时间序列。5.进行时间序列预测方法的研究，建立关于系统输出的ARMA模型。通过变换将该模型转换为AR模型，同时采用随机近似方法对其进行求解，得到无时滞的估计输出序列。这一过程从根本上消除了时滞的影响，为不依赖模型的控制算法提供有效的控制器输入。6.根据实际工程应用和试验研究的需求，分别建立工程控制系统和地面试验系统。结合Borland C++软件开发平台编制控制软件，通过对DAQ2206数采卡进行接口和信号传输操作，实现计算机与恒流源、功率放大器等外部设备的通讯。采用多线程技术实现数据接收、输送以及计算机内部运算的同步进行，为控制系统的实时工作提供保障。7.结合地面试验控制系统对文中提出的控制方法进行试验验证，同时将部分控制方法应用于工程控制系统。更多还原

【Abstract】 The active vibration control of structures suffering from complex excitations is aninterdisciplinary subject involving the scientific research fields of structural dynamics, control theory,signal processing, computer application, etc. The kinetic study of distributed structures suffering fromcomplex excitations has long attracted the attention of scholars. However, complex excitationsprovide this type of structure with nonlinear dynamical behaviors such as bifurcation, chaos, etc.These complicated phenomena are induced by the infinite dimensional characteristic of continuousstructures, and it is easy to induce observation and control spillover when discrete time controlalgorithms are applied. This problem will influence the system’s instability. Therefore, the system’srobustness and anti-jamming performance should be further considered. In general, studying problemsinvolving distributed structures suffering from complex excitations is a great challenge, with a strongengineering background and scientific significance.Based on the vibration control of a wind tunnel model suffering from a transonic wind load, thisstudy examines the dynamical phenomena and control methods for a distributed structure sufferingfrom complex excitations. The main research contents and contributions are as follows:1. A control algorithm based on the input estimation method is studied, using a system withdeterminate model parameters. An unknown disturbance is introduced into the controllerdesign to improve control effect. Systems can be converted to a new state equation withoutan explicit disturbance in combination with a random walk model. Thus, it is easy to acquirethe estimated value of the new state equation by using a Kalman filter, which contains theestimated value of the unknown disturbance. Therefore, the estimated value can be used inthe linear quadratic gauss method to express the math of a controller with a disturbance.2. An anti-aliasing filter and high-order low-pass digital filter are introduced to avoid theinfluence of noise induced by the high-order mode of the distributed structures. The linearrelationship is regarded approximately as the phase-to-frequency characteristic in thepass-band of the filters. Considering the invariant time delay induced by the filters, thestability of the controlled system is studied, and the stability regions of the system areconfirmed by the stability switch theory.3. Delay usage and elimination methods are studied to design controllers adapted to the case ofsystems with output time delays. From the aspect of delay usage, an appropriate time delaycan be determined according to the decay rate of the impulse response. The controlled effect can be greatly improved through a time delay reset. From the aspect of delay elimination, adiscrete state equation is constructed without an explicit time delay, and is combined with alinear quadratic control method to obtain a controller with a time delay.4. Considering the nonlinear phase-to-frequency characteristic in the transition bandwidth offilters, the problem induced by a system’s variable time delay is studied. To deal with thisnew problem, the variable time delay system is converted to a fixed one using a phasecompensation method. A credible output time series is established for further study on theelimination of overall delay.5. A time series forecasting method is studied, and an ARMA model is established based on thesystem output. To obtain a serial output without a time delay, the model is transferred to theAR form, and is solved using a stochastic approximation method. This process essentiallyeliminates the influence of time delay and provides an effective controller input for thecontrol algorithm independent of the model parameters.6. Based on an actual engineering application and experimental research, an engineeringcontrol system and ground test system are established. Application software is developed forthe control system based on the Borland C++software development platform. In addition,the connections between a computer and a constant current source, power amplifier, andother peripheral equipment are established by using a data acquisition card (DAQ2206). Toprovide protection for real-time applications, multithreading technology is adopted to ensurecomputer and data transfer synchronization.7. The proposed control methods are validated on the ground test system, and some of them areapplied in the engineering control system.更多还原