基于自适应滤波算法的超声波气体流量计

Ultrasonic Gas Flowmeter Based on Adaptive Filtering Algorithm

针对超声波气体流量计在使用过程中普遍存在的测量精度不高、稳定性差等问题,提出并实现了基于时差法和新型自适应滤波算法的超声波气体流量计。该流量计硬件部分由STM32F103主控芯片、高精度计时芯片TDC-GP22等组成,保证了系统的计量精度;软件部分采用了一种改进型卡尔曼滤波算法,在保证滤波效果的同时有效提高响应速率,并且将其与算术平均滤波相结合,根据流体渡越时间差的变化率提出了新型自适应数据滤波算法。通过实验对比发现,该新型滤波算法有效降低了系统的测量误差,在0.25~40 m^(3)/h流量范围内,系统的最大测量误差为1.08%,满足1.5级精度标准,同时使得系统零漂减小为原来的一半,大大提高了系统的稳定性,满足了实际工程应用的需要。

Aiming at the problems of low measurement accuracy and poor stability in the use of ultrasonic gas flowmeter,ultrasonic gas flowmeter based on time-difference method and new adaptive filtering algorithm was proposed and implemented.The hardware part of the flowmeter was composed of STM32F103 main control chip and TDC-GP22 high precision timing chip,which ensured the measurement accuracy of the system.An improved Kalman filtering algorithm was used in the software part,which can ensure the filtering effect and effectively improve the response rate,and combined with the arithmetic average filtering,a new adaptive data filtering algorithm was proposed according to the change rate of fluid transit time difference.Through experimental comparison,it is found that the new filtering algorithm can effectively reduce the measurement error of the system,and the maximum measurement error of the system is 1.08%in the flow range of 0.25~40 m^(3)/h,which meets the 1.5 level accuracy standard.At the same time,the zero drift of the system is reduced to half of the original,which greatly improves the stability of the system and meets the needs of practical engineering applications.