Road Vehicle Dynamics
Research focus
The Peer review has evaluated this group as Excellent
The Research Group acquired a several year experience in utilizing commercial multi-body programs to simulate vehicle passive behaviour and to optimize both vehicle handling and ride comfort. A 14 degrees of freedom car-vehicle model was developed in cooperation with Pirelli Tyres; the vehicle model was developed in Matlab/Simulink environment which is particularly suitable for the implementation of control logics; with this approach the model can be easily used for optimization procedures and transferred on real-time boards to be used in Hardware-In-the-Loop simulations. The model, carried out inside the EC project VERTEC, has been validated through a series of experimental tests and has been used as reference model for a driving simulator developed by VTI. A race driver model has also been developed in order to evaluate the handling performance of a vehicle at its limit. A cooperation with Fiat Auto and TRW lead respectively to development of accurate models of the powertrain and steering systems, both introduced in the 14 d.o.f model. A motorcycle model and experimental tests were carried out to evaluate the driver+vehicle response. As far as heavy vehicle is concerned multi-body models of trucks and agricultural vehicle were developed on the basis of indoor and outdoor experimental tests. Important experimental campaigns were carried out on different trucks instrumented with a series of accelerometers and strain gauges on both the chassis and the suspensions’ elements, allowing to acquire data relevant to vehicle dynamics and to define the components load spectra. Wind tunnel tests have been performed within the WEATHER European Project in order to characterize the aerodynamic properties of several heavy vehicles simulating different atmospheric boundary layer conditions and scenarios (viaduct, flat ground, embankment, etc.). The research group gained a profound experience in the use and developing of tyres model. A cooperation with Centro Ricerche Fiat led to the identification of the so called “scaling factors” of MFTyre model on the basis of an extensive series of experimental tests. A rigid ring tyre model has been developed over the last years in cooperation with Pirelli Tyres for both comfort and handling analysis; during the EC founded project TROWS, focused on tyre wear, a very refined model of the contact patch dynamics was completed and a wear model was included thus allowing to predict tyre wear considering the tread pattern design; good results were obtained comparing the model outputs with the experimental results collected in TROWS. Several analysis concerning the influence of tyre and vehicle parameters on tread compound wear were carried out. The tyre model is being currently with the introduction of belt flexibility. Active control systems development relies upon the models previously described and used to simulate the behaviour of the tyres, the vehicle and its components. The Research group developed a series of techniques to estimate quantities not measured on board but which can provide important information for active control systems such as tyres cornering stiffness and vehicle sideslip angle. Moreover a cooperation with Pirelli Tyres led to the definition of patented algorithm for the estimation of contact forces starting from sensors introduced in the tyres or from strain gauges mounted on the rim . An HIL test bench has also been set-up to analyse the behaviour of the ABS controller; models for ABS and VDC were set-up starting from this experience. In cooperation with CRF, Fiat Auto and Ferrari Auto, the Research Group has led a large research activity on active control. An example of the obtained results, is a semi-active electronic differential for a 2WD vehicle that equips the F430 Modena. The possibility of using the brakes torque in order to increase the vehicle performance has been analysed and a control strategy has been set up. In the field of active/semi-active suspensions the Research Group started both a numerical (actuators modelling) and experimental activity. Several kinds of control strategies have been investigated: semi-active dampers (cooperation with Ferrari S.p.A.), active control of suspensions’ kinematics, in particular of camber angle (cooperation with Bridgestone). During the last year a hybrid Fiat Punto was set-up thanks to a Lombardia Region founded project. The experience gained in this research area allowed to design and build the FSAE race car of Politecnico di Milano.
Dipartimento di afferenza
Docenti afferenti
Full Professors
Federico Cheli
Ferruccio Resta
Associate Professors
Roberto Corradi
Assistant Professors
Francesco Braghin
Stefano Melzi
Gisella Tomasini