ROLL CENTER AND CENTRODES OF AN EIGHT-BAR SUSPENSION SYSTEM

This paper deals with the roll motion analysis of vehicles which are provided of two double wishbone independent suspension mechanisms on the front side. According to a planar car model and supposing that both front wheels are rotating about their fixed revolute joints, the position analysis of an eight-bar mechanism is formulated, in order to determine the position of the roll center, along with the fixed and moving centrodes. In particular, all instantaneous centers of rotations have been determined by devoting particular attention to the roll center and to those of each wheel with respect to the vehicle chassis, according to the kinematic characteristics of the double wishbone independent suspension mechanism. Moreover, a suitable mechanism with 18 members and 1 d.o.f. is proposed to generate mechanically or by using any CAD-software, both centrodes, according to the direct and inverse planar motion of the chassis with respect to the ground and vice versa. Finally, a first curvature analysis is carried out by using the Euler-Savary equation and the inflection circle, in order to determine the center of curvature of the mass center trajectory for the chassis roll motion. The proposed formulation has been implemented in a Matlab program and several examples allowed its validation in different mechanism configurations. © 2023 American Society of Mechanical Engineers (ASME)