Riassunto analitico
Ensuring safety is a primary concern for automobiles, but for super-sport vehicles the performance and the fun-to-drive element are mandatory prerequisites. One way to reach this target is to increase the maneuverability of the vehicle. A better handling and stability gives the driver a better control of the car when at the limit of the adherence, which could occur either during an emergency maneuver or when driving around a racetrack. A very effective way to enhance maneuverability is to exploit a torque vectoring strategy, which makes possible to manage the traction on the four wheels efficiently and so enlarge the driving area.
In this work, a TV strategy based on a direct yaw moment controller (DYC) has been proposed for RWD and AWD vehicles. It has been designed for vehicles with independent torque actuation, considering possible both driving and braking actuations. The optimal torque distribution is calculated according to a DYC strategy that splits the torque between right side and left side according to the deviation of the vehicle yaw velocity from a reference yaw velocity. Additionally, for the 4WD vehicle a longitudinal torque distribution is done, based on vertical tire forces and yaw velocity error. A new Traction Control Systems, that exploits the friction ellipse formulation, has been proposed to partner with the TV system to ensure that the calculated distribution respects the tires adherence limit. Finally, the control algorithm has been tested through computer simulations and using a driving simulator.
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