To calibrate the accelerometer, relate the voltage signal from the accelerometer to a know acceleration. Use the forced response of the apparatus to produce a known acceleration.
The solution to the differential equation that governs the forced response of the apparatus is:
(1)
(For more information on the forced response solution see: Forced Vib Eqn Solution.)
The acceleration is determined by differentiating Equation 1 with respect to time twice and is represented by:
(2) .
By forcing the apparatus at different driving frequencies, we can calculate the acceleration at the peaks from:
(3) .
By measuring the peak-to-peak voltage or the RMS voltage of both the accelerometer and a displacement measurement device (e.g., LVDT) the acceleration of the beam can be related to the accelerometer signal.
The slope of the acceleration versus voltage graph is the Accelerometer's sensitivity. Make sure you compare the measured sensitivity to the manufacturer's stated sensitivity on the Accelerometer data sheet.
Tip: Recall that the piezoelectric accelerometer is only sensitive to fluctuating accelerations. AC couple the accelerometer signal because the DC signal tends to drift.
