基于压电智能结构的振动主动控制算法研究

发布时间：2018-09-10 14:42

【摘要】：现如今导航系统、测试系统等诸多结构对精准度的要求越来越高,但环境或内部的扰动引起结构振动是不可避免的,振动往往会导致结构性能下降甚至结构损坏,为此研究解决实际工程中结构振动问题的方法十分必要。压电智能结构作为一种新兴起的主动结构,因其独特的压电效应、良好的机电耦合性等而被广泛应用到振动控制系统中。压电智能结构在实际应用中受到外部和内部多重不确定扰动,故寻求简单又实时有效的振动主动控制方法成为迫切需要研究的课题之一。本文针对压电智能结构在复杂扰动下的振动,着重研究了基于扰动观测和反馈的复合振动主动控制算法。首先结合实际根据压电智能结构中传感器/作动器的数目配置,将系统分为单输入单输出型、多输入多输出型、多输入单输出型三种情况分别建立状态空间方程。然后针对反馈控制的迟缓性和扰动信号难建模等问题,设计出基于扰动观测和PID控制的复合控制算法,不同模型下的振动控制仿真结果得出:(1)复合算法在不同模型中都具有一定的适用性,在外部扰动激励下,复合控制器对结构振动的抑制效果可以达到70%左右,比单独的反馈控制器效果要好1.2-2倍;(2)控制算法的性能与结构模型相关,对结构进行多模控制时,复合控制算法的独立模态控制可以避免模态之间耦合影响,具有一定的优良性;(3)系统为单输入时,采用两个作动器的控制效果比采用一个作动器的效果要好将近一倍。最后分别考虑系统存在传感器量测噪声和时滞量对复合算法进行了改进,仿真结果表明:(1)复合控制器对高频量测噪声不具有抑制作用,改进后的控制器可以使高频段噪声对系统影响降低40dB以上;(2)在复合控制算法下,系统时滞易引起响应初期幅值增大,且单个振荡周期的时滞量超过40%时系统易发散,加入自适应Smith预估器的改进算法能有效补偿系统时滞且允许存在预估偏差。本文所设计的复合控制算法及其改进补偿结构简单、适用性强,在较全面考虑了结构模型和结构中可能存在的扰动情况下,仿真结果都达到了较满意的效果,对实际的振动主动控制具有一定的指导意义。
[Abstract]:Nowadays, many structures, such as navigation system, test system and so on, require more and more precision, but the vibration caused by the environment or internal disturbance is inevitable. The vibration often leads to the deterioration of the structure performance and even the damage of the structure. Therefore, it is necessary to study the method to solve the structural vibration problem in practical engineering. As a new active structure, piezoelectric intelligent structure is widely used in vibration control system because of its unique piezoelectric effect and good electromechanical coupling. Piezoelectric intelligent structures are subjected to multiple external and internal uncertainties in practical applications. Therefore, it is urgent to seek a simple, real-time and effective active vibration control method. Aiming at the vibration of piezoelectric intelligent structures under complex disturbances, the active control algorithm of composite vibration based on disturbance observation and feedback is studied in this paper. Firstly, according to the number of sensors / actuators in piezoelectric intelligent structure, the system is divided into three types: single input, single output, multiple input and single output. Then, a compound control algorithm based on disturbance observation and PID control is designed to solve the problem of the delay of feedback control and the difficulty of modeling disturbance signal. The simulation results of vibration control under different models show that: (1) the composite algorithm has certain applicability in different models. Under the excitation of external disturbance, the effect of the composite controller on the vibration of the structure can reach about 70%. (2) the performance of the control algorithm is related to the structure model, and the independent modal control of the composite control algorithm can avoid the coupling effect between the modes when the structure is controlled by multiple modes, the performance of the controller is 1.2-2 times better than that of the single feedback controller, and (2) the performance of the control algorithm is related to the structure model. (3) when the system is single input, the control effect of using two actuators is nearly twice as good as that of using one actuator. Finally, the hybrid algorithm is improved by considering the presence of sensor measurement noise and time-delay, respectively. The simulation results show that: (1) the composite controller can not suppress the high-frequency measurement noise. The improved controller can reduce the influence of high frequency noise on the system by more than 40dB. (2) under the compound control algorithm, the initial amplitude of the system is easily increased when the delay of the system is longer than 40, and the system is prone to divergence when the time delay of a single oscillation period exceeds 40. The improved algorithm with adaptive Smith predictor can compensate the delay of the system effectively and allow for the existence of prediction deviation. The compound control algorithm designed in this paper and its improved compensation have simple structure and strong applicability. The simulation results are satisfactory when the structure model and the possible disturbances in the structure are considered comprehensively. It has certain guiding significance for active vibration control.
【学位授予单位】：中北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TP273;TN384

【参考文献】