A Study on Development and Applications of Feedforward Adaptive Control

前馈控制通过有效地利用可达信号，可以大大提高控制性能。由于它依赖于被控系统模型的精度，因此需要开发具有保证稳定性和收敛特性的自适应方法。主要研究成果如下：(1)提出了一种新的适用于一般多通道有源噪声控制(ANC)和多通道声复制(SRP)的直接自适应方法。为了降低抵消或重构误差，引入了两种虚拟误差，并通过在线调整三个自适应FIR滤波器矩阵来强迫它们为零，从而使实际抵消误差在目标点收敛到零。与其他传统方法不同，该算法可以直接给出逆控制器，而不需要显式地识别次级路径信道，并且不需要任何抖动信号…提出了一种新的用于补偿高功率放大器(HPA)非线性的时域自适应预失真方案。提出了一种带记忆的幂级数模型(PSMWM)，用来近似描述具有动力学特性的高功率放大器的非线性输入输出关系。利用PSMWM实时计算HPA的补偿输入，使得即使在HPA的非线性输入输出关系不确定和变化的情况下，也能实现从预失真器输入到HPA输出的线性化。通过对64QAM--ofdm系统的数值仿真，验证了所提出的自适应补偿方案的有效性。(3)磁流变阻尼器是一种很有前途的半主动结构振动控制装置。给出了一个具有少量模型参数的简单的磁流变液阻尼器的数学模型，用以描述磁流变液的非线性动态摩擦机构的迟滞行为。提出了一种能够估计不确定模型参数和内部状态变量的自适应辨识算法。该模型的优点在于，通过其逆模型，我们可以解析地确定磁流变阻尼器所需的输入电压，以便以自适应的方式将期望的阻尼力添加到结构中。实验结果验证了所提出的自适应建模与控制方案在三层结构隔振中的有效性。较少

The feedforward control can much improve control performance by effectively using accessible signals. Since it depends on accuracy of the model of controlled systems, adaptive approaches with assured stability and convergence should be developed. The research results are summarized as follows :(1)A new direct adaptive approach is proposed for general multichannel active noise control(ANC) and multichannel sound reproduction (SRP) when all of the path channels are uncertain and changeable. To reduce the canceling or reconstruction errors, two kinds of virtual errors are introduced and are forced into zero by adjusting three adaptive FIR filter matrices in an on-line manner, by which the convergence of the actual canceling errors to zero can be attained at the objective points. Unlike other conventional approaches, the proposed algorithm can give an inverse controller directly without need of explicit identification of the secondary path channels, and requires neither any dither signals … More nor the PE property of the source signals, which is a great advantage of the proposed approach.(2)A new time-domain adaptive predistortion scheme has been developed for compensating nonlinearity of high power amplifiers (HPA) in OFDM systems. A power series model with memory(PSMWM) is proposed to approximately describe the nonlinear input-output relation of HPA with dynamics. By using the PSMWM, the compensation input to HPA is calculated in a real-time manner so that the linearization from the predistortor input to the HPA output can be attained even if the nonlinear input-output relation of HPA is uncertain and changeable. The effectiveness of the proposed adaptive compensation scheme is validated by numerical simulation for 64QAM--OFDM systems.(3)Magnetorheological(MR) damper is a promising semi-active device for vibration control of structures. A simple mathematical model of MR damper with a small number of model parameters has been given to express its hysteresis behavior of nonlinear dynamic friction mechanism of the MR fluid. The adaptive identification algorithm is also proposed in which the uncertain model parameters and internal state variable can be estimated. The proposed model has an advantage that by using its inverse model we can analytically determine the necessary input voltage to the MR damper so that the desirable damper force can be added to the structure in an adaptive manner. Experimental results validate the proposed adaptive modeling and control schemes in vibration isolation of three story structure. Less