Two Axes Electro-hydraulic Platform for Generating Stochastic Vibrations

From the point of view of the oscillatory comfort of cars, it is very important to study the transmission of vibrations through the human body and their influence on the psychophysical characteristics of men. In most cases of interest there are stochastic vibrations of the frequency band 1Hz-30Hz, but previous research in this field has shown that human beings are very sensitive to the frequencies less than 1Hz, such as 0.1Hz or even less (to about 0.05Hz). This paper presents the practical realization of a two-axis electro-hydraulic platform and corresponding control system for generating stochastic vibrations in order to examine the oscillatory comfort of truck seats. The control system is based on monitoring narrowband and broadband reference waveforms generated by the method of direct digital synthesis (DDS). The realized two-axis electro-hydraulic system can also be used for vibration testing of other loads up to 200kg in the frequency range 0.1-30Hz. The verification of the realized system was confirmed by the experimental results given at the end of the paper. The presented system was realized at the Faculty of Engineering, University of Kragujevac at the Department for Motor Vehicles and Motors.