Modeling of Hydrogas Unit for Tracked Vehicle Suspension

Abstract

Tracked vehicles equipped with conventional suspension are limited in their ability to achieve high mobility. This limitation is due to the linear characteristics and the consequent poorer ride performance [1-3]. Hydro gas suspension due to their inherent non-linear behavior can provide higher mobility and better ride comfort performance [4]. This paper aims to evaluate the characteristics of hydro-gas suspension system and apply this nonconventional system for the armored fighting carrier BMP-1. To achieve this goal, theoretical and experimental studies were carried out. The theoretical study includes modeling of the hydro gas suspension unit mathematically and validation of the developed model using MATLAB/SIMULINK. The experimental measurements are carried out to validate the results obtained from the model. The force, created inside the hydro gas unit during its action, includes the elastic and damping forces, the variation of such force with displacement and velocity of moving part are recorded (obtained). This variation is used as input parameters in the equation of oscillation of vehicle hull to study its vibration response. The obtained results show that the proposed hydro gas suspension system is more acceptable than the conventional one. Keywords: tracked vehicle suspension, hydrogas suspension system, hedrogas unit. Nomenclature area of orifice, m 2 A o area of floating piston, m 2 A f area of the piston, m 2 A p area of rod, m 2 A r Bulk , s modulus 0f oil, Pa Β discharge coefficient viscous friction coefficient for the piston, Ns/m C d C v viscous friction coefficient for the floating piston, Ns/m Ff mass of floating piston, kg m f mass of piston, kg m p flow rate of oil through the orifices, m 3 /s Q pressure in the lower fluid chamber, pa P 1 pressure in the upper fluid chamber, pa P 2 nitrogen gas pressure in the nitrogen chamber, pa P g initial pressure of nitrogen gas in nitrogen chamber, pa P o volume of lower chamber, m 3 V 1 volume of upper chamber, m 3 V 2 initial volume of nitrogen chamber, m 3 V o volume of nitrogen in nitrogen chamber, m 3 V g displacement of floating piston, m X displacement of the rod, m Z Hydro gas Suspension Unit HSU Paper: ASAT-16-015-HF 1. Introduction As the operating speed of high mobility tracked vehicle increases, the vibration induced by rough road condition also increases and it induces fatigue on crew members and many delicate instruments inside the vehicle. Also, vibration in a gun barrel reduces t…