User Evaluation of Passenger Assistance System Concepts on Public Highways

There is ample research on assistance systems for drivers in conventional and automated vehicles. In the past, those systems were developed to increase safety but also to increase driver comfort. Since many common risks have by now been mitigated through such systems, the research and development focus expanded to also include comfort-related assistance. However, the passenger has rarely been taken into account explicitly, although it has been shown that passenger discomfort is a relevant problem. Therefore, this work investigated the potential of passenger assistance systems to reduce such discomfort. Three different passenger assistant system prototypes were tested in a driving study on public highway with N = 19 participants. The systems provided information about parameters related to the performance of the driver and one additionally provided a communicative means of influence. For two passenger assistant systems, it could be shown that they significantly reduced passenger discomfort in at least a subset of the evaluated situations. The majority of participants rated one or multiple of the assistant systems as more comfortable than a ride without assistance. The system providing information about the attentiveness of the driver was most effective in reducing discomfort and was rated as the most helpful system. The results show that explicitly considering the situation of passengers in the design of assistance systems can positively impact their comfort. This can be achieved using information from common systems targeting driver assistance available to the passenger.

Operation of T-Foils and Stern Tabs to Improve Passenger Comfort on High-Speed Ferries

High-speed ferries of around 100 m length cruising at around 40 knots can cause significant passenger discomfort in head waves. This is due to the frequencies of encountering waves, of maximum hull response to encountered waves and of maximum passenger discomfort all falling within a similar range. In this paper, the benefit obtained by fitting active T-foils and stern tabs to control heave and pitch in head waves is considered. Ship motion responses are computed by numerical integration in the time domain including unsteady control actions using a time domain, high-speed strip theory. This obviates the need to identify transfer functions, the computed time responses including nonlinear hull immersion terms. The largest passenger vertical accelerations occur at forward locations and are best controlled by a forward located T-foil acting in combination with active stern tabs. Various feedback control algorithms have been considered and it is found that pitch damping control gives the greatest improvement in passenger comfort at forward positions. Operation in adaptive and nonlinear modes so that the control deflections are maximized under all conditions give the greatest benefit and can reduce passenger motion sickness incidence (MSI) by up to 25% in a 3-m head sea on the basis of International Organization for Standardization (ISO) recommendations for calculation of MSI for a 90-minute seaway passage.

Study of a Half Car Suspension Model

In this paper, a model with four degrees of freedom is studied to assess the discomfort of car passengers due to vibrations. The response of the half car model due to road irregularities is presented in order to attain a control method for the dampers. For the analytical study, the differential equations of the motion were written in order to determine the critical frequencies. The resulted model takes into account both the forced and damped solution for a numerical case, thus giving a more detailed overview of the phenomena. Using this numerical case, a control method can be developed to reduce the passenger discomfort, based on the motion diagrams.