Force Sensor Characterization Under Sinusoidal Excitations
The aim in the current work is the development of a method to characterize force sensors under sinusoidal excitations using a primary standard as the source of traceability. During this work the influence factors have been studied and a method to minimise their contributions, as well as the corrections to be performed under dynamic conditions have been established. These results will allow the realization of an adequate characterization of force sensors under sinusoidal excitations, which will be essential for its further proper use under dynamic conditions. The traceability of the sensor characterization is based in the direct definition of force as mass multiplied by acceleration. To do so, the sensor is loaded with different calibrated loads and is maintained under different sinusoidal accelerations by means of a vibration shaker system that is able to generate accelerations up to 100 m/s2 with frequencies from 5 Hz up to 2400 Hz. The acceleration is measured by means of a laser vibrometer with traceability to the units of time and length. A multiple channel data acquisition system is also required to simultaneously acquire the electrical output signals of the involved instrument in real time.
Primary accelerometer calibration problems due to vibration exciters
Abstract The purpose of this paper is to review and discuss the main problems that occur in primary accelerometer calibration due to the use of imperfect vibration exciters. These problems include low moving element stiffness, heating of the accelerometer under calibration, rocking and transverse motion, resonances, harmonic distortion and noise. Methods undertaken to minimize the effects of such problems are discussed and some calibration results are presented herein.
The application of Bessel function methods on high-frequency vibration calibration
Bessel function methods are used on high-frequency vibration calibration. In this paper, a general principle, devices, methods and uncertainty evaluations will be introduced. There are four methods based on Bessel function, which include J0 minimum-point method, J1 minimum-point method, J1 ratio method and J1/J2 ratio method. About this calibration system, the frequency range is 2 ~ 50) kHz and the displacement range is (0.002~0.2) μm. At the same time, two important things will be described, one is a frequency-adjustable piezoelectricity vibrator which is good for high-frequency vibration calibration on account of almost no equilibrium excursion, and the other is double-holes method used in evaluating the linearity of laser interferometer which is important for calibration.