Abstract: A signal waveform analysis method includes: determining a trend component of an object signal by applying a zero-phase filter to the object signal; determining an oscillatory component of the object signal by removing the trend component from the object signal; determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component; and determining an oscillation period of the object signal with which the wavelet scalogram indicates a maximum. The signal waveform analysis method is employed to evaluate vehicle dynamic characteristics.

Abstract: A signal waveform analysis method includes: determining a trend component of an object signal by applying a zero-phase filter to the object signal; determining an oscillatory component of the object signal by removing the trend component from the object signal; determining a wavelet scalogram by performing a wavelet analysis on the oscillatory component; and determining an oscillation period of the object signal with which the wavelet scalogram indicates a maximum. The signal waveform analysis method is employed to evaluate vehicle dynamic characteristics.

Abstract: A testing apparatus of a steering system is provided to correctly detect load in a direction in which steering reaction force acts, the load being applied to the steering system. A tie rod connected to a rack of the steering system is connected to a steering-angle vibrating unit via a torque lever, relay links and a drive link. A front link of the drive link and a link disposed parallel to the torque lever are provided in a swingable manner. Both ends of each of the relay links are respectively connected to the torque lever and the link disposed parallel to the torque lever, and the torque lever is swingable with respect to the link in a direction in which road-surface reaction force acts. Transducers are provided at intermediate portions of the relay links, respectively. A vertically-vibrating unit is connected via the torque lever to the rack.