Model Validity in Observers: When to Increase the Complexity of Your Model?

Model validity is key to the accurate and safe behavior of autonomous vehicles. Using invalid vehicle models in different plan and control vehicle frameworks puts the stability of the vehicle and, thus, its safety at stake. In this work, we analyze the validity of several popular vehicle models used in the literature with respect to a real vehicle and we prove that serious accuracy issues are encountered beyond a specific lateral acceleration point. We set a clear lateral acceleration domain, in which the used models are an accurate representation of the behavior of the vehicle. We then target the necessity of using learned methods to model the vehicle’s behavior. The effects of model validity on state observers are investigated. The performance of model-based observers is compared to learning-based ones. Overall, this work emphasizes the validity of vehicle models and presents clear operational domains in which models could be used safely.