Mitigation of motion sickness in automated vehicles

This dissertation addresses the pressing challenge of motion sickness in automated vehicles, emphasising the development of motion planning and control strategies to enhance passenger comfort. With the advent of autonomous driving, vehicles are no longer controlled by a driver who can intuitively adjust manoeuvres based on passenger comfort, making the issue of motion sickness more prominent. Automated driving offers numerous benefits and can lead to unpredictable vehicle dynamics from a passenger’s perspective, resulting in a heightened incidence of discomfort and motion sickness. This dissertation investigates methods to mitigate these effects to improve user experience and support wider acceptance of autonomous vehicle technology. The research begins by exploring the phenomenon of motion sickness and examining its causes, symptoms, and physiological impacts on passengers. Various theories are reviewed to explain why motion sickness occurs, including sensory conflict, postural instability, and subjective vertical mismatch theories, each offering insight into how human perception and control systems respond to unpredictable or sustained vehicle motion. The dissertation delves into methods for evaluating motion sickness, discussing different models, questionnaires, and indexes that quantify the likelihood or severity of motion sickness in various driving scenarios. Furthermore, it examines existing mitigation methods, categorising them into three broad approaches: behavioural practices, medical and supplementary solutions, and technological interventions related to vehicle design and control. This comprehensive understanding of motion sickness forms the foundation for the control and planning strategies proposed later in the dissertation. A central focus of the research is motion planning for comfort, identifying the significance of designing trajectories that reduce abrupt changes in speed and direction. Motion planning is positioned as one of the most promising methods for mitigating motion sickness, as it allows for pre-emptive control of vehicle dynamics to maintain smooth and predictable motion. The dissertation evaluates several planning algorithms and methodologies, illustrating how strategic trajectory design can contribute to reducing the lateral and longitudinal forces that typically lead to discomfort. By emphasising smooth, predictable movements, motion planning significantly enhances passenger comfort, supporting the hypothesis that a tailored approach to trajectory design can minimise motion sickness. In addition to motion planning, the dissertation explores nonlinear model predictive control (NMPC) algorithms, which are particularly suited to handling the complex, nonlinear dynamics involved in automated driving. Several NMPC strategies are discussed, including traction control, torque vectoring, and active suspension systems. Through simulations and experiments, the NMPC strategies demonstrate their capacity for precisely modulating vehicle dynamics, paving the way for further investigation of their efficiency in counteracting the potential sources of motion sickness by keeping movements within comfortable bounds. This combination of motion planning and NMPC strategies could offer a holistic approach to enhancing passenger comfort in autonomous vehicles. The findings illustrate that by integrating smooth trajectory planning with advanced control algorithms, it is possible to create an automated driving experience that prioritises comfort and reduces the risk of motion sickness. Concluding the dissertation, the research points to future directions that could build on these results, such as refining motion sickness modelling, developing more adaptive control systems, and validating the methods in real-world driving scenarios. Through its in-depth investigation of motion sickness and its proposed mitigation methods, this dissertation contributes valuable insights to the field of autonomous vehicle design, aiming to make autonomous driving more comfortable and appealing for passengers.