Abstract

This paper describes a multi-degree-of-freedom model of a three-wheeled car,
implemented in Matlab®. The purpose was to investigate the dynamics of the car
(assumed to be rigid on its suspension) during cornering. While the problems
associated with three-wheeled cars are well-known, much of the guidance in the
literature and off-the-software assumes a conventional four-wheeled car.
Consequently, the authors were approached with a battery-electric concept car which
was thought to offer better performance than existing variants, because the use of hub
motors lowered the centre of gravity and hence reduced rollover coefficient. However,
simulation of the vehicle model in cornering shows that the concept is still prone to
instability. Indeed, it suffers greater roll velocities than a comparable three-wheeled car
with internal combustion engine, because the ratio of sprung to unsprung mass is
significantly altered. This paper therefore recommends a programme of further
simulations and model-based design changes to progress the concept to a marketable
performance product.