【摘要】 在周期振动的自适应控制中,压电作动器的非线性特性会产生高次谐波,激发高阶模态振动。为抑制压电作动器的高次谐波激励,同时结合自适应振动控制的特点,提出一种新的作动器非线性补偿方法。该方法将作动器的非线性与结构的动态特性部分融合,用正交多项式从输入输出信号中拟合静态非线性及其逆变换,计算过程简单,数值稳定性高。在控制通道中,通过逆变换对控制信号进行预处理,使得补偿后的输入输出具有线性系统的特征,而输入输出之间的相位差完全由自适应算法进行补偿。实验结果表明,所给出的补偿方法能够抑制高次谐波,并改善了振动控制效果。更多还原

【Abstract】 In adaptive control of periodic vibrations,the nonlinear characteristics of piezoelectric actuators can cause higher order harmonics in control forces,which definitely excites higher-frequency vibrations in structures.To suppress the excitation of these harmonics,a new method in combination with the adaptive control algorithm was presented to compensate the output nonlinearity of piezoelectric actuators.Using the method,the actuator’s nonlinearity and the structural dynamic features were combined and represented with a static nonlinear mapping and a pure phase-shift unit,and orthogonal polynomials were employed to identify the static nonlinearity from the input/output signals and to establish an inverse compensation model.The computation in modeling was relatively simple and numerically robust.The control signal was preprocessed with the inverse compensation model to make the control channel act as a linear system,and the phase difference between the input/output signals was compensated completely using the adaptive controller.The experimental results demonstrated that the presented method is able to suppress higher order harmonics and improve the performance of piezoelectric actuators in vibration control.更多还原