变结构PID在微机械陀螺仪闭环驱动电路中的应用

为满足微机械陀螺仪(MMG)闭环驱动电路起振快速、无超调且稳态精度高等要求,提出了一种基于FPGA的数字化变结构PID控制器,并以其为核心构建了微机械陀螺仪的数字化闭环驱动电路.通过构造以控制误差为自变量的比例增益、积分增益和微分增益函数,使变结构PID的结构和参数能够根据瞬时误差的变化而变化,以提高闭环驱动电路的性能.针对某型微机械陀螺仪敏感结构参数,进行了SIMULINK仿真,仿真结果表明以变结构PID为核心的闭环驱动电路是可行的.起振实验结果表明,经典PID构成的闭环驱动电路,其检测电压的幅值超调量达到了75%,稳定时间为2 s;采用变结构PID控制器后闭环驱动检测电压的幅值无超调且稳定时间为0.7 s;1 h的稳定性实验表明,采用经典PID时检测电压幅值的长期稳定性为2.73×10-5V,采用变结构PID时其稳定性为2.68×10-5V,证明变结构PID可以兼顾系统在快速性、超调量和稳态精度等方面的要求.

Application of Variable Structure PID to Closed-Loop Drive Circuit of Micro-Machined Gyroscope

In order to meet the requirements of fast start-up, no over-shoot and high precision in steady-state for micro-machined gyroscope （MMG） closed-loop drive circuit , a digital variable structure PID controller based on FPGA was proposed, and a digital closed-loop drive circuit of MMG was built with the variable structure PID as its core. By constructing the functions of control errors, such as pro- portional gain, integral gain and differential gain, the structure and parameters of the variable structure PID controller can be made to change in real time with input error, so as to improve the performance of closed-loop drive circuit. A simulation model was built in SIMULINK based on the sensitive structural parameters of one type of MMG, and the simulation result shows that the variable structure PID is fea- sible in the closed-loop drive circuit. The start-up experimental result shows that the over-shoot of de- tection voltage was 75% and the stability time was 2 s based on the closed-loop drive circuit of classi- cal PID; while there was no over-shoot and the stability time was 0.7 s based on that of variable struc- ture PID; experiment for 1 h shows that the long-term stability of detection voltage amplitude was 2.73×10^-5 V for classical PID, and 2.68×10^-5 V for variable structure PID,which proves that the vari- able structure PID can take a balance between time, over-shoot and precision in steady-state.