Advanced brake assist systems can avoid road accidents since the vehicles impact speed can be significantly reduced. To this end, different autonomous emergency braking systems are designed for recent vehicles on the market. This paper presents a pneumo-hydraulic Emergency Braking System (EBS) for autonomous racing vehicles. The purpose of the system is safely stopping the vehicle in case of any failures during autonomous driving. Failures can be detected both by the autonomous system itself and by human supervisors. The actuation system involves passive energy storage of compressed air to directly activate the hydraulic braking lines through pneumo-hydraulic pressure intensifiers. The coupling component between failures detection and actuation is a normally-open solenoid valve. The system is designed to respect deceleration and actuation time requirements, together with packaging constraints due to integration in an existing racing prototype. Specifically, the system requirements are specified by the racing competition rules: the overall reaction time of the retained EBS must be lower than 0.2 s, and the actuated mean deceleration must be greater than 8 m/s² on a dry track surface while keeping stable driving conditions. The validation and tuning of the system is performed in a simulated environment. Therefore, an extensive experimental validation of the system is required in the real applications.

The electrification trend characterizing the current automotive industry creates opportunities for the implementation of innovative functionalities, enhancing aspects of energy efficiency and vehicle dynamics. Active vehicle suspensions are an important subsystem in this process. To enable proper suspension control, vehicle sensors can be used to measure the system’s response and, in some cases, preview the road conditions and the presence of possible obstacles. When assessing the performance of a suspension system, the speed bump crossing represents a challenging maneuver. A suitable trade-off between comfort and road holding must be found through different phases of the profile. The proposed work uses a fixed-gain observer obtained from Kalman filtering to identify road unevenness and adapt the control strategy when the vehicle travels through a bump. To this end, the obstacle is identified through the use of affordable sensors available in high-end vehicles: accelerometers, inertial measurement units, and stroke sensors. The proposed technique is also affordable from the computational point of view, thus enabling its use in common microprocessors tailored for the automotive field. The bump identification technique is validated through experimental data captured in a vehicle demonstrator. Subsequently, numerical results show that the proposed technique is able to enhance comfort while keeping road holding and attenuating the transient after taking the bump.

The development of chassis technologies has pushed significant focus towards electrification for enhanced vehicle efficiency, flexibility, safety, and performance. In this context, the suspension represents a key system, as it strongly influences both vehicle dynamics and comfort. The trend is to replace the usual hydraulic damper with mechatronic actuators. Rotary electromagnetic shock absorbers are among these solutions, featuring a rotary electric machine and a proper rotary-to-linear transmission stage. Far from being ideal force sources, these actuators may introduce inertial, compliance, and friction phenomena to the suspension. This paper proposes a generalized equivalent model to reproduce the mechanical behavior of electromagnetic shock absorbers. The formulation of this tool helps compare different shock absorber technologies in terms of their dynamic response. Furthermore, it can be used to synthesize control strategies that account for intrinsic limitations of chassis actuators.

Active suspension systems are gaining growing attention in the automotive industry. This trend aligns with vehicle electrification and X-by-wire technologies adoption, also answering to the increasingly stringent requirements for passenger comfort and safety. Among the possible solutions, electromechanical actuators represent a valid alternative to traditional shock absorbers, integrating an electric machine that can be easily controlled to deliver the desired forces in both active and passive operations. The present work aims at developing an innovative transmission compound for a rotary electromagnetic active suspension system that is able to obtain high level NVH and safety performances. Two different proposed systems are analyzed. The first one couples a cycloidal transmission stage to a polymeric planetary one, while the second one couples the same cycloidal stage to a concentric magnetic gearbox. Both of them are expected to improve the NVH performances of the shock absorber, thanks to the high efficiency of the cycloidal reducer and to the properties of plastic materials and of magnetic coupling. The proposed systems are analyzed analytically and in simulation environment, providing promising results in terms of efficiency and torque density.