有源静电轴承起支过程的非线性控制

Nonlinear control of active electrostatic bearings for initial levitation

静电球轴承起支过程中,双边支承下的非线性与轴间耦合较强,必须配置支承垫才能实现任意姿态起支。为了解决静电球轴承无支承垫时的任意姿态起支问题,研究了基于无预载电压偏置的单边支承控制方法。根据非线性的静电力模型,应用反馈线性化方法构造出非线性控制器,使得系统在大范围内精确线性化,然后应用线性系统理论进行设计。实验结果表明,结合单边支承方案与非线性控制方法能够实现静电轴承在任意姿态下的平稳起支,无需配置支承垫,大大简化了对支承电极的工艺要求。

For electrostatically suspended spherical bearings, conventional linear control via a fixed bias voltage necessitates supporting lands to achieve a steady rotor levitation over the entire bearing orientations due to the highly nonlinear and coupled equations describing the electrostatic bearings. A suspension control without voltage bias was developed that achieves steady rotor levitation in any orientation for a class of electrostatic bearings without supporting lands. A nonlinear controller was designed using the nonlinear electrostatic force model and linearized using feedback linearization to precisely linearize the whole system with a linear controller then designed for the linearized system. The experimental results demonstrate that the nonlinear suspension control system without voltage bias achieves smooth bearing rotor levitation for various initial orientations without supporting lands with a significantly simplified housing design.