有源静电悬浮系统的反馈线性化控制

Feedback linearization of active electrostatic levitation systems

静电轴承需要一套静电悬浮系统将高速旋转的转子稳定地支承在电极球腔中心,被控对象呈现非线性与负刚度特性。在推导静电悬浮系统的高阶静电力模型基础上,应用反馈线性化方法,构造出非线性控制器,能够使得系统在大范围内线性化。将传统的线性控制器与提出的非线性控制方案在三自由度静电悬浮系统上进行了实验比较。实验结果表明,将反馈线性化方法应用于静电悬浮系统,提高了系统的动态性能、稳定裕量和中频支承刚度。

An electrostatic levitation system is required to suspend the rotating rotor of an electrostatic bearing centered in a vacuum cavity. The nonlinearities and negative stiffness characteristics inherent in most types of levitation systems have a significant impact on the control performance. Therefore, a nonlinear controller design based on the dynamic equations for the system model and feedback linearization techniques was utilized to stabilize the levitation system. A three degrees of freedom electrostatic levitation system was designed and constructed to compare the performance of linear and nonlinear digital control schemes in a wellcontrolled experimental environment. The experimental results demonstrate the superiority of nonlinear controllers relative to conventional controllers in terms of performance, stability, and suspension stiffness.