A Method for Synchronous Shock Calibration of Triaxial High-g Accelerometers Based on Modified Hopkinson Bar Technique
Qinghua Wang, Kangbo Yuan, Meng Gao, Feng Xu, Weiguo Guo
Abstract
Since the width of the excitation pulse is generally in the order of microseconds to milliseconds, the key technique in the shock calibration of triaxial high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}$ </tex-math></inline-formula> accelerometer is how to achieve the synchronous loadings with high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}$ </tex-math></inline-formula> amplitude along the three orthogonal axes. Given this background, this article developed a synchronous calibration method for the triaxial high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}$ </tex-math></inline-formula> accelerometers by modifying the conventional Hopkinson bar method. Using this newly developed method, 3-D reference acceleration pulses with an amplitude range of 104–105 and a width range of 101– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$102 \mu \text{s}$ </tex-math></inline-formula> can be generated and imposed on the triaxial high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}$ </tex-math></inline-formula> accelerometers synchronously. Then, calibration experiments on a typical triaxial high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}$ </tex-math></inline-formula> accelerometer were carried out by using both the synchronous calibration method and the conventional Hopkinson bar method. The sensitivity of the triaxial accelerometer was characterized by a matrix, the so-called sensitivity matrix, containing three main sensitivity coefficients and six transverse sensitivity coefficients. A least squares method (LSM) was used to calculate the sensitivity matrix. A generalization error was employed to evaluate the measurement accuracy of the accelerometer. The results show that the measurement accuracy of the triaxial high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}$ </tex-math></inline-formula> accelerometer calibrated by the synchronous method is higher than that calibrated by the conventional asynchronous method. Therefore, the developed synchronous method is recommended to ensure and improve the measurement accuracy of the triaxial high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${g}$ </tex-math></inline-formula> accelerometers. Finally, the validity and calibration ability of the newly developed method were numerically investigated and discussed in detail.