基于正弦激励的压电加速度计模型参数辨识

Calibration of Piezoelectric Accelerometer’s Dynamic Characteristics using Primary Vibration Calibration

针对压电加速度计常规校准无法完全满足实际机械动态量测量要求的问题,采用基于加速度计模型参数校准的方法。参数未知的线性二阶微分方程用来表示加速度计动态特性,利用绝对法振动校准加速度计频率响应数据,采用最小二乘算法确定了未知的参数的值,同时利用蒙特卡罗法确定了参数值的不确定度。最后对加速度计进行了瞬态冲击加速度校准,计算辨识所得模型在相同冲击激励下的预测输出。结果表明:瞬态冲击加速度校准与计算辨识模型结果相差不超过1%。

A novel approach was proposed for calibration of accelerometers by model-based parameter identification,aimed for the problem that mostly used method for accelerometer s calibration can t satisfy requirements for dynamic mechanical quantity in reality.The model consisted of a linear,second-order differential equation with unknown coefficients.It was proposed to estimate these model parameters from primary vibration calibration,and an estimation procedure based on linear least-squares was presented.The uncertainties associated with the estimated results were determined utilizing a Monte Carlo simulation technique.The model obtained was used to predict the accelerometer s behavior for shock acceleration,measured and predicted results were consistent with difference below 1%,which confirmed the validity of the method.