静电悬浮六轴微加速度计单边支承起支控制

Unilateral Suspension Control for the Initial Levitation of a Micromachined Electrostatically Suspended Six-Axis Accelerometer

给出了一种基于微电子机械系统(MEMS)技术的静电悬浮微加速度计(MESA),其主要由上定子、质量块和下定子组成。采用力平衡原理和力矩平衡原理可同时测量三轴线加速度和三轴角加速度,即对质量块实行闭环控制使质量块保持在零位,输出控制电压反映壳体输入加速度的大小。设计出基于混合微制造技术的微加速度计结构和加工工艺,制造出静电悬浮微加速度计原型机,进行静电悬浮六轴微加速度计的控制和检测方案设计,为了克服质量块远离平衡位置的非线性特性,根据非线性的静电力模型设计出无预载电压的单边支承控制器。通过实验结果可以看出,采用无预载电压的单边支承控制器实现起支时,超调量为12%,调节时间为16.6 ms,表现出良好的动态性能和全局稳定性,证明了该控制方法的准确性和有效性。

A micromachined electrostatically suspension accelerometer(MESA)based on the micro-electromechanical system(MEMS)technology was presented,and was mainly composed of the upper stator,proof mass and lower stator.The three-axis linear acceleration and three-axis angular acceleration can be measured simultaneously by using the force balance principle and moment balance principle,i.e.,the proof mass can be kept in the null position by the close-loop control and the output control voltages reflect the input acceleration from the shell.The structure and fabrication process of the micro accelerometer were designed based on the hybrid micro fabrication technology,and the prototype of the MESA was fabricated.The control and detection scheme of the six-axe MESA was designed.In order to overcome the nonlinear characteristics of the proof mass far away from the null position,a unilateral suspension controller without the preload voltage was designed based on the nonlinear electrostatic force model.With the experimental results,it can be seen that as adopting the unilateral suspension controller without the preload voltage,the overshoot for the initial levitation is 12%and the settling time is 16.6 ms,displaying agood dynamic performance and global stability of the system and proving the accuracy and effectiveness of the control method.