DEVELOPMENT OF A FLAT-SURFACE TEST STAND FOR INVESTIGATIONS ON DRIVING DYNAMICS

Abstract

Road-test research on braking dynamics led to the knowledge of global and local system behaviour and to the wish to investigate local effects under defined and repeatable, but still real conditions. To meet all these requirements the quarter-car flat-surface test stand 'EFA' with the ability to simulate vehicle dynamics of a quarter-car three-dimensionally was developed and built by the Institute of Automotive Engineering (f z d) of the Technical University of Darmstadt (THD). Based on the principle of kinematic inversion a flexible power-drive belt made of polyamide coated with elastomer simulates the moving road surface with a μ-slip characteristic like dry asphalt up to a maximum speed of 100 km/h. Realistic vertical excitation of the quarter-car with real suspension, body mass and ABS is possible by moving the wheel support under the belt with frequencies up to 2.5 Hz and amplitudes up to 40 mm. This concept enables to measure dynamic wheel load up to 15.000 N directly in the road. The research work presented here shows the necessity and advantage of a fiat-surface test stand for investigations on braking dynamics under real conditions and describes the concept for these investigations for the future.