Abstract
Recent advances in dependable embedded-system technology, as well as continuing demand for improved handling and passive and active safety improvements, have led vehicle manufacturers and suppliers to work to develop computer-controlled, by-wire subsystems with no mechanical link to the driver. These include steer-by-wire and brake-by-wire and are composed of mechanically decoupled sets of actuators and controllers connected through multiplexed in-vehicle computer networks. Actually, the success of such projects is highly dependant on the concurrent design of vehicle mechanics and control architecture and the mechatronic integrated approach is essential feature for the development of effective realisations; therefore, the availability of computer-aided modelling tools is basic requirement to assess beforehand systems behaviour since the first design stages through dynamic simulation and virtual prototyping.
The present paper describes the architecture of a drive-by-wire controller that allows an electric city car to achieve good dynamic performances through a "joystick" human-machine interface; the independent motorization of the front wheels and a full-state sensorisation have been duly exploited to augment the standard capabilities of steer-by-wire vehicles. The referenced city-car has been studied by Tonino Lamborghini G.C. and Carrozzeria Suzzarese in cooperation with the University of Ancona, that developed a 7 d.o.f.s model to assess controllers performances by computer simulation, according to the different required performances or available sensing information.