Abstract
The authors have been developing a vibration characteristic estimation method using the accurate small vibrator. In this method, acceleration responses excited by the accurate small vibrator are measured with accelerometers and converted to displacement time series. The displacement time series and the force function of accurate small vibrater are described by an ARX (Auto-Regressive eXogeneous) model. The frequency transfer function and vibration characteristics are estimated by solving the ARX equations with least-squares method.
In this research, We apply the prototype system to a road sign and estimate the vibration characteristics. In this experiment, a weight of 1.5kg is fixed to the road sign and the change of eigen frequency of the mode with the largest amplitude is accurately determined. However the eigen frequency of the mode with second largest amplitude is less accurately estimated. The estimation accuracy is verified by analyzing a simulation data of two degree of freedom system and an experimental data obtained in a laboratory scale vibration test using a steel simple beam.
