Vehicle sideslip angle is a key state for lateral vehicle dynamics, but measuring it is expensive and unpractical. Still, knowledge of this state would be really valuable for vehicle safety systems aimed at enhancing vehicle safety, to help to reduce worldwide fatal car accidents. This has motivated the research community to investigate techniques to estimate vehicle sideslip angle, which is still a challenging problem. One of the major issues is the need for accurate tyre model parameters, which are difficult to characterise and subject to change during vehicle operation. This paper proposes a new method for estimating vehicle sideslip angle using an Extended Kalman Filter. The main novelties are: i) the tyre behaviour is described using a Rational tyre model whose parameters are estimated and updated online to account for their variation due to e.g. tyre wear and environmental conditions affecting the tyre behaviour; ii) the proposed technique is compared with two other methods available in the literature by means of experimental tests on a heavy-duty vehicle. Results show that: i) the proposed method effectively estimates vehicle sideslip angle with an error limited to 0.5 deg in standard driving conditions, and less than 1 deg for a high-speed run; ii) the tyre parameters are successfully updated online, contributing to outclassing estimation methods based on tyre models that are either excessively simple or with non-varying parameters.

The interest in high-altitude pseudo-satellites (HAPSs) has significantly increased in recent years due to the great versatility of these platforms, which allows them to be employed in a wide variety of applications in civilian and military fields. This study focuses on the design of an innovative hybrid airship vertical tail. The empennage proposed is internally sustained with a light-weight structure and coated with a thin film, avoiding any leakage that would occur with inflated structural elements. The design of the vertical tail and its structural analysis through a detailed finite element (FE) model are presented to show its overall behavior subjected to the aerodynamic loads.