The tyre-soil effects on the manoeuvrability of a city-car

Eco-compatibility aims at drastic changes of people transportation means and, to grant proper mobility levels, the electrically-powered city-car concept provides effective solutions. This quite obviously leads to distributed actuation, with separately driven wheels, and inconsistencies appear unless redundancy and tyre/road interaction are properly mastered. The paper deals with the dynamics of such kind of vehicle moving from the behaviour of driven wheels (with compliant tyre and varying soil interactions); then a twin powered axle or train are investigated as basic reference to describe the dynamics of a four wheels platform, driven by redundant actuation on varying friction soils. On these premises, a city car manoeuvre stability can be stated for low speed tasks over urban roads. Results are obtained, after modelling the wheel dynamics, with resort to computer simulation, based on the SIMULINK package; the kinematics constraints are introduced and the varying tyre-soil coupling conditions are related with the driving torque options.