Longitudinal Dynamic Metrics for Describing and Developing the Deceleration Behavior of Vehicles in the Concept Phase

The brake system is a critical safety component in motor vehicles. Advances in the electrification of the powertrain and the rise of autonomous driving technologies are profoundly influencing the brake system, driving innovative approaches to brake concepts and necessitating the development of new deceleration strategies. A significant technological advancement is the decoupling of the driver from the brake system through Brake-by-Wire technology. A crucial attribute is the attainment of a consistent and concept-independent deceleration behavior and pedal feel. To establish a consistent and OEM-specific deceleration behavior and pedal feel in the early development phase, objective criteria and perceptual thresholds are required, describing the desired subjective braking behavior. Moreover, objective criteria are indispensable for the virtual phase of the vehicle development process. In this article the focus is in deceleration from a straight-ahead drive. To identify objective criteria and perceptual threshold, a testing procedure and a set of potentially robust metrics are first defined based on literature, expert knowledge, and specific driving characteristics related to deceleration. Suitable criteria and perceptual thresholds are then derived from a subjective evaluation study, objective measurements, and subsequent correlation analysis. As a result, objective criteria for stationary deceleration, latency and deceleration build-up were established. A subsequent benchmark of current vehicles demonstrates the applicability of the identified criteria.