Abstract:

Active vibration control of a smart flexible cantilever beam was studied by using mode theory and μ synthesis method. The actuator was piezoceramic patch, the sensor was strain gauge. The finite element method and experimental modal test were applied to obtain the dynamic model of the structure. Meanwhile, the results of comparative analysis of the two methods show there are errors between the finite element model and the actural system. Taking account into uncertainty of the external disturbance and measurement noises, and uncertainty of natural frequency, damping ratio and actuator parameters of the system, a μ synthesis approach was applied to design the vibration controller by selecting mode displacement as evaluation signal and selecting appropriate weighting function according to amplitude and frequency characteristics of the actual signals. First, the effectiveness of the controller was analyzed from a frequency domain point of view. The results show the controller can inhibit the impact of the uncertain disturbances on output strain, and can meet the control requirements in the case of uncertainty. Thus, the controller is robust. Second, the experiments on vibration control were performed. The experimental results show that the proposed controller can suppress the vibration response of the structure effectively.

Key words: smart structure;active vibration control;finite element method;&mu, synthesis;experimental modal test

摘要：

利用模态理论和μ综合方法,对智能柔性悬臂梁进行振动主动控制研究。以压电陶瓷为作动器，电阻应变计为传感器，采用有限元方法和实验模态测试方法建立结构动力学模型,对两种方法所得结果进行比较分析可知有限元模型与实际系统存在误差。考虑外部扰动和量测噪声的不确定性，同时考虑系统固有频率、阻尼比和作动器参数的不确定性，选择模态位移信号为评价量,根据信号的频率特性选择合适的加权函数，利用μ综合方法设计振动控制器。从频域角度分析控制器的有效性，结果表明该控制器能抑制不确定干扰对输出应变的影响，能在系统不确定性情况下满足控制要求,说明控制器具有鲁棒性。进行了振动主动控制实验研究,结果表明,所设计的控制器能有效抑制结构的振动响应。

关键词: 智能结构, 振动主动控制, 有限元法, &mu, 综合, 实验模态测试