On the Experimental Analysis of Integral Sliding Modes for Yaw Rate and Sideslip Control of an Electric Vehicle with Multiple Motors

With the advent of electric vehicles with multiple motors, the steady-state and transient cornering responses can be designed and implemented through the continuous torque control of the individual wheels, i.e., torque-vectoring or direct yaw moment control. The literature includes several papers on sliding mode control theory for torque-vectoring, but the experimental investigation is so far limited. More importantly, to the knowledge of the authors, the experimental comparison of direct yaw moment control based on sliding modes and typical controllers used for stability control in production vehicles is missing. This paper aims to reduce this gap by presenting and analyzing an integral sliding mode controller for concurrent yaw rate and sideslip control. A new driving mode, the Enhanced Sport mode, is proposed, inducing sustained high values of sideslip angle, which can be limited to a specified threshold. The system is experimentally assessed on a four-wheel-drive electric vehicle. The performance of the integral sliding mode controller is compared with that of a linear quadratic regulator during step steer tests. The results show that the integral sliding mode controller significantly enhances the tracking performance and yaw damping compared to the more conventional linear quadratic regulator based on an augmented singletrack vehicle model formulation.     

Italian ports: towards a new governance?

The adoption in 1994 of the law n. 84 introducing the landlord port model marked the starting point of a prime period for the Italian port industry. It contributed to the national port industry renaissance: Italian ports became again the leaders in the Mediterranean basin, both as gateway ports and as transhipment ports. Looking back to its 15 years of enforcement, critical aspects and weaknesses have been observed. The incentive to reflect on the governance structure of ports and on the changes affecting the whole logistics transport chain is driven by the relative and absolute loss of position of Italian ports with respect to their competitors of the North as well as of the South European range (and the ports of Northern Africa which are expected to compete fiercely in the coming future). Considering only the container traffic, from 2003 to 2008 the market share of Italian ports decreased from 20.7% to 15.7% in favor of its main European competitors. The loss of attractiveness of Italian harbors is a clear symptom of the several difficulties national ports face in dealing with the rapid changes affecting the port industry. This paper discusses the bill presented by the Italian Government concerning the ports governance reform.