压电宏纤维致动器的双极性非对称迟滞建模及补偿控制

提出了一种双极性非对称改进PI(Bipolar Asymmetric Improved PI,BAIPI)模型描述压电宏纤维(Marco Fiber Composite,MFC)的迟滞特性,BAIPI模型利用经典Prandtl-Ishlinskii(PI)迟滞模型Play算子加权叠加描述MFC的对称迟滞特性,然后叠加一系列不同权重、不同阈值的双边死区算子描述MFC的双极性非对称特性。实验辨识结果表明:BAIPI模型对MFC致动器的建模误差从PI迟滞模型的16.8%降为4.2%。在基于BAIPI逆模型的前馈补偿下,MFC致动的柔性梁构件跟踪等幅、变幅三角波轨迹的实测位移与期望跟踪位移基本重合,补偿后等幅三角波实测位移与理想位移之间的线性度为2.36%。因此,所提出BAIPI迟滞模型及补偿方法显著提高了MFC致动器的定位驱动和跟踪精度。

Modeling and feedforward comprehension control on the bipolar asymmetric hysteresis of marco fiber composite(MFC)actuators

Macro fiber composite(MFC)affords notable advantages of good flexibility,high deform ability and large actuation ability,and has been widely used in the precision engineering and active deformation control,etc.However,the actuation and positioning accuracies of the MFC actuators are reduced due to their asymmetric hysteresis nonlinearity.A Bipolar Asymmetric Improved PI(BAIPI)hysteresis model is proposed to describe the hysteresis nonlinearity of MFC actuators.The BAIPI model is composed of two parts:the weighted superposition of the play hysteresis operators based on the classical PI hysteresis model is introduced to deal with the symmetric hysteresis nonlinearity.And the asymmetric bipolar phenomenon is described by the linear superposition of many double-sides dead-zone operators with different threshold and weight values.Experimental identification results show that the hysteresis modeling error of the MFC-actuated cantilever system reduces to 4.2%using the proposed BAIPI model,while that of the PI model is 16.8%.With the feedforward compensation method based on the inverse BAIPI model,the measured tracking trajectories of the triangular wave with consistent and random amplitudes are in good agreement with the desired trajectories,and the linearity between the desired and compensated trajectories achieves 2.36%.As a result,the effectiveness and feasibility of the proposed BAIPI hysteresis model and feedforward compensation method is demonstrated.