Minimizing the uncertainty in the calibration of accelerometers by the reciprocity method requires minimizing the cross-axis component of the induced motion, and the distortion of its waveform. Minimizing the uncertainty in the calibration of accelerometers by the laser interferometric fringe-counting method requires minimizing the mechanical coupling between the moving element of the shaker and the optical components of the interferometer. The design of the new shaker provides for minimal distortion and cross-axis motion in combination with a very large mechanical impedance between the moving element of the shaker and the optical components of the interferometer. The shaker is equipped with dual coils and two retractable magnets to provide for reciprocity measurements without having to attach a secondary source of vibration located external to the moving element. This paper presents a comparison of calibration results obtained using the two methods and describes the shaker and calibration systems.
Pub Type: Journals
accelorometers, calibration, exciters, fringe counting, laser interferometer, reciprocity shakers, uncertainty