硅压阻式压力传感器测量误差在线补偿方法研究

Research on on-line compensation method for the measurement error of silicon piezoresistive pressure sensor

由于硅压阻式压力传感器的测量精度易受温漂和非线性等因素影响,而现有测量误差数字补偿方法实时性不高,因此提出了一种基于二元插值算法的异频分步在线补偿方法。首先采用三次样条插值算法对传感器输出电压和工作温度插值,抑制温漂;然后利用拉格朗日插值算法对压力和电压进行分段插值,减小非线性误差;同时降低温度的插值频率以减少每个压力插值周期内计算量,克服了传统的插值补偿方法将两个变量在一个插值周期内计算时间长的缺点。通过传感器标定和误差补偿实验验证了该方法的补偿精度在0~60℃的温度范围内满足±0.05%FS的误差要求,并且在设计的采集系统上实现1 kHz的数据输出速率。实验结果表明该方法可以有效地提高硅压阻式压力传感器的测量精度,且具有较高的实时性,能够实现误差在线补偿。在航空发动机试验的气体压力测量中具有一定的工程应用价值。

The measurement accuracy of silicon piezoresistive pressure sensor is subject to the influence of temperature drift,nonlinear error and etc.,existing measurement error numerical compensation methods have low real-time performance.A step-by-step different frequency compensation method based on two element interpolation is proposed.The method is implemented as follows:firstly,the cubic spline interpolation algorithm is used to interpolate the output voltage and working temperature of the sensor,and suppress temperature drift;and then,Lagrange interpolation algorithm is used to interpolate the pressure and voltage piecewisely,and reduce the nonlinear error;meanwhile,the frequency of the temperature interpolation is decreased to reduce the calculation burden in each pressure interpolation period,and overcome the shortcoming that traditional interpolation compensation method calculates two variables in one interpolation period and the calculation is time-consuming.Experiments on sensor calibration and error compensation were conducted,the results verify that the compensation accuracy meets the error requirement of±0.05%FS in the temperature range of 0~60℃,and the data output rate of 1 kHz is achieved in the designed acquisition system;the experiment results indicate that the proposed method can effectively improve the measurement accuracy of silicon piezoresistive pressure sensor,has good real time performance and can realize error on-line compensation.The proposed method possesses a certain engineering value in the gas pressure measurement in aeroengine tests.