基于趋近律离散滑模控制的柔性梁振动抑制

Vibration Suppression of Flexible Beam Based on Discrete Sliding Mode Control with Reaching Law

研究了基于趋近律的离散滑模控制在智能柔性悬臂梁振动控制中的应用。以压电陶瓷为作动器,电阻应变片为传感器,采用有限元方法和模态截断技术建立结构动力学模型。由于柔性结构系统受到不确定外部扰动和量测噪声的影响以及参数的不确定性,滑模变结构控制可以实现滑动模态与系统的外干扰和参数摄动无关,即滑动模态的不变性。结构振动控制在系统状态由于外部干扰的影响偏离平衡状态,在控制器作用下能使系统趋于零状态。采用趋近律离散滑模控制方法设计状态调节器。由于状态量不能直接测量,故利用离散卡尔曼滤波技术构造状态估计器。采用试验模态测试方法得到结构的前4阶固有频率和阻尼比,与有限元方法的结果比较,说明该模型的正确性。使用dSPACE实时仿真系统和MATLAB/Simulink搭建控制系统,进行了振动主动控制试验。试验结果表明,所设计的控制器能有效抑制结构的振动响应。

Application study of discrete sliding mode control based on reaching law on vibration control of smart flexible cantilever beam is performed.The actuator is piezoceramic patch,the sensor is strain gauge.The finite element method and modal truncation technique are used to obtain the dynamic model of the structure.Because flexible structure system is influenced by uncertain external disturbances and measurement noise,and its parameters are uncertain,sliding mode variable structure control can assure that sliding mode of the system is independent on exogenous disturbances and parameter perturbation,that is,it has invariance of the sliding mode.The purpose of vibration control is that the controller enables the system to be zero state as the system states are away from the equilibrium one due to external disturbances.The discrete sliding mode control approach with reaching law is used to design the state regulator.The discrete Kalman filtering technique is employed to construct state estimator because the state variables cannot be directly measured.The first four natural frequencies and damping ratio are obtained by using experimental modal testing.Comparing with the results obtained by the finite element method,it shows that the model is correct.Using dSPACE real-time simulation system and MATLAB/ Simulink,the control system is built and the active vibration control study is carried out.Experimental results show that the designed estimator is effective and the proposed controller can suppress the vibration response of the structure.