DYNAMIC ANALYSIS OF VEHICLE SYSTEMS Development of a driving simulator Analysis and design of an automatic transmission for motor-scooters

In this work, two researches in the field of dynamic analysis of vehicle systems are presented. The first part of the thesis deals with the development of a driving simulator. This activity was carried out in the framework of a research project co-funded by the Italian Ministry of Education, Universities and Research (MIUR). It aimed at developing a driving simulator for the analysis of the driving style, in order to identify potentially dangerous conditions coming from a non proper interaction between driver, vehicle and environment, especially those related to low driver’s attention. As core part of the driving simulator, a vehicle simulation model, which reproduces the behaviour of the main vehicle systems, was developed. The simulator is made of a fixed driving platform, a single channel visual system and allows to acquire all driver’s inputs and vehicle motion signals. The system was involved in experimental campaigns which allowed the development of the driving style analysis techniques and demonstrated the reliability and the capability of the system. The second part of the thesis treats the dynamic analysis and design of a high efficiency automatic transmission for motor-scooters and was carried out in the framework of the Italian MUSS project funded by the Italian Ministry of Economic Development. Motor-scooters are currently almost always equipped with CVT transmission with rubber belt. This transmission can be very cheap to manufacture, it has good comfort performance but low mechanical efficiency. An alternative automatic transmission was analysed and different architectures were studied. The system is based on a discrete ratio gear box with mechanical control of the gear shit by means of centrifugal clutches and free wheels. A dynamic model of the transmission was developed and its behaviour was investigated by means of results of simulated manoeuvres, highlighting the positive and negative aspects of the system. Finally, a preliminary design was also carried out with reference to an application of the transmission in a hybrid powertrain.