No abstract

Electric vehicles are spreading in automotive industry pushed by the need of reducing greenhouse gas. However, the use of multiple electric motors, i.e., one per wheel, allows to redefine the vehicle powertrain layout with great benefits on vehicle dynamics. Electric motors braking torque is in general not enough to produce high decelerations. Hydraulic friction brakes are still necessary for safety reasons and to avoid oversized motors. This paper presents a control strategy for distributed electric motors (EM), one per wheel, to maximize the regenerative braking. The controller handles cooperative braking among EMs and hydraulic brakes, which are still necessary to guarantee top braking performance of the car. The proposed algorithm considers the driver requested braking torque as well as the required yaw moment by stability control system. Motor efficiency map and wheel normal load are considered to optimally distribute the torques. With respect to conventional distribution strategies, the presented algorithm improves performance, maximizing the regenerative braking power.

No abstract

<div class="section abstract"><div class="htmlview paragraph">Multi-purpose agricultural tractors are vehicles that are usually used in rough paths and on off-road situations characterized by strong slope variations. The main feature of this kind of vehicles is the stability in working conditions to avoid overturning while it is on duty. This characteristic is given by the interaction between the suspension system and the vehicle frame. Due to the limited size of this kind of vehicle, the stability feature could be given by chassis deformation or using a two-piece frame connected by a spherical joint. This paper presents the validation of a numerical lumped-parameters model able to reproduce the vertical dynamics of a multi-purpose tractor featured by a yielding chassis. The unknown model parameters have been estimated firstly with static tests to study the vertical tire and suspension stiffnesses. The dynamic tests using a four-post-test rig have been performed to tune the unknown dynamic parameters. Finally, the model has been validated with some in-field acquisition to reproduce the real vehicle working conditions.</div></div>