高精密定位平台驱动波纹管迟滞的建模与验证

Hysteresis Modeling and Verification of Pneumatic Bellows in High-precision Positioning Stage

为了提高精密定位平台的精度和行程,设计了一种新型的气动伺服定位平台。以金属波纹管为独立执行机构,采用有限元法设计了气浮导轨。以气浮导轨支撑,研究无摩擦条件下的较大行程的精密控制。对波纹管的机械特性进行分析,结合实验数据形成的迟滞初载曲线,进行参数辨识,确定基本迟滞算子的阈值和权值,建立了基于PI模型的系统迟滞模型,并对模型进行了验证。结合建立的系统迟滞模型,采用变化速率为0.5 V/s和5 V/s的锯齿波进行实验,结果表明:系统的迟滞模型输出很好地逼近了系统输出;开环情况下,实际逼近误差慢速信号输入逼近小于10%m,快速信号输入逼近小于20%m,其性能上能够满足高精密定位平台的精度要求。

In order to improve the accuracy and stroke of a precision positioning stage,a new precision pneumatic servo positioning stage was designed. The metal bellows were used as an independent driving device in this system,and the air bearing sliders were designed by finite element method( FEM). The motion stage was supported by air bearing slider,and the high precision with large stroke was studied under the condition of without friction. The mechanical characteristics of bellows were analyzed,and the system parameters were identified in connection with the experimental data to establish the hysteresis curves of preloading. The threshold and power values of basic hysteresis operators were determined,and the system hysteresis model based on PI model was established,and the model was verified. Saw-toothed wave on the changing rate of 0. 5 V / s and 5 V / s were used in the experiments in connection with the established model. The experimental results show that the system hysteresis model is a very good approximation to the system output. In the case of open-loop,errors between the model output and the system output are less than 10 %m on the slow rate signal input,and are no more than 20 %m on the fast signal input. Its performance can reach the accuracy requirements of the high-precision positioning stage.