基于电流变阻尼超精密气浮工作台建模及控制研究

随超精密装备加工精度和生产率的不断提高,直线气浮系统得到广泛重视和研究。为解决直线气浮系统抗干扰能力较差等问题,针对已开发的超精密直线气浮工作台,设计了电流变剪切模式阻尼器;建立了气浮工作台整体模型并基于屈服前后平滑过渡的Eyring连续本构模型通过辨识得出电流变剪切阻尼器类稳态模型;分别对零电场线性及高电场非线性电流变阻尼2种情况下的气浮工作台应用误差积分LQR控制器;为达到综合最优,进一步提出开关及滑模控制器,实验证实这2种控制策略均能同时提高系统的响应速度、减少建立时间,降低跟踪误差及纹波。

A Study on Ultra-precision Gas Bearing Stage Equipped with Electrorheological Damper

With the increasing demands for higher accuracy and higher productivity of the ultra-precision equipments,ultra-precision gas bearing stage systems driven by linear motor become research hotspots.To overcome the demerits such as the low positioning stability due to outer disturbances etc.,an electrorheological shear damper was developed and installed on an established ultra-precision gas bearing stage system.The whole stage model was established.Through an experimental identification,the electrorheological fluid(ERF) damper characteristics under various electric fields were obtained based on an Eyring constitutive model,which has a smooth transition from preyield to postyield region.By comparing the LQR control response of the stage with zero electric filed ERF with that with high field ERF damper,the on-off controller and sliding model controller were developed.The experimental results verify that both controllers can simultaneously improve the stage performances such as response velocity,anti-disturbance capacity and positioning accuracy etc.