Vehicle Dynamics Control System Actuating an Active Differential

In the last years automotive industry has shown a growing interest in exploring the field of actively controlled differentials due to the promising expectations of their application for the improvement of handling performances. The differential here considered has two clutches, which connect each driveshaft with a second part that, through a gear, always rotates faster. This device allows the control system to transfer torque from one wheel to the other one, almost independently from their relative velocity. The results of this preliminary modeling phase are shown in the first part of the paper. The control algorithms development has been carried out using a vehicle model that can precisely simulate the handling response, the powertrain dynamics and the actuation system behavior. To obtain a representative powertrain response, the development of a customized library in Simulink has been required. Applying a methodology commonly shared among car manufacturers, for this research a two-steps approach has been adopted: firstly an intensive simulation campaign has been executed to design and tune the controller in the virtual environment; secondly the logic has been tested using HIL techniques. The second part of the paper introduces the general structure of control system developed and its main algorithms. Vehicle performance improvements, evaluated through simulation and HIL tests, are underlined.