基于FPGA的硅微陀螺数字测控和温补技术研究

Research on Digital Measurement and Control and Temperature Compensation Technology of Silicon Micro Gyro Based on FPGA

硅微陀螺仪由陀螺结构和测控电路组成,随着模拟接口电路的日臻完善,陀螺仪性能的提升主要靠数字电路中的测控和补偿算法;目前硅微陀螺测控电路正在向芯片化方向发展,为了加速硅微陀螺测控电路芯片化进程,用Verilog硬件描述语言设计了AGC和PLL对陀螺幅度和相位进行闭环控制,科氏力平衡进行闭环检测;对因加工造成的正交误差,设计了正交校正闭环;根据温度对陀螺仪的影响,对标度因数进行线性补偿,对零偏进行了BP神经网络补偿;实验结果表明,该控制系统下AGC相对稳定性为124 ppm,PLL相对稳定性为79.1 ppm,常温零偏稳定性为2.9°/h;在0~65℃内补偿前零偏稳定性为17.7°/h,补偿后零偏稳定性为9.1°/h,标度因数温度灵敏度降低1个数量级,不仅提升了硅微陀螺仪的性能,也为陀螺ASIC设计奠定了良好基础。

A silicon micro gyroscope consists of a gyroscope structure,and measurement and control circuit.With the improvement of analog interface circuits,the improvement of gyroscope performance mainly relies on the measurement and control and compensation algorithms in digital circuits.At present,the measurement and control circuits of silicon micro gyroscopes are developing in the direction of chip technology.In order to accelerate the process of chip-based measurement and control circuits of silicon micro gyroscopes,Verilog HDL is used to design AGC and PLL for the closed-loop control of gyroscope amplitude and phase,and Coriolis force balance for the closed-loop detection.An orthogonal correction closed-loop was designed to address the orthogonal errors caused by processing.Based on the influence of temperature on the gyroscope,linear compensation was applied to the scale factor,and BP neural network compensation to the zero bias.The experimental results show that after this control system is applied,the relative stability of AGC is reached by 124 ppm,the relative stability of PLL by 79.1 ppm,and the zero bias stability of normal temperature conditions by 2.9°/h;The zero bias stability before compensation is reached by 17.7°/h within the temperature range of 0℃to 65℃,and the zero bias stability after compensation by 9.1°/h.The temperature sensitivity of the scaling factor is reduced by one order of magnitude.The research results not only improve the performance of silicon micro gyroscopes,but also lay a good foundation for gyro ASIC design.