Abstract

Introduction of automated driving increases complexity of automotive systems. As a result, architecture design becomes a major concern for ensuring non-functional requirements such as safety, and modifiability. In the ISO 26262 standard, architecture patterns are recommended for system development. However, the existing architecture patterns may not be able to answer requirements of automated driving completely. When applying these patterns in the automated driving context, modification and analysis of these patterns are needed. In this paper, we present a novel architecture pattern for safety critical automated driving functions. In addition, we propose a generic approach to compare our pattern with a number of existing ones. The comparison results can be used as a basis for project specific architectural decisions. Our Safety Channel pattern is validated by its implementation for a real-life truck platooning application.

Abstract

This paper presents a method for trajectory control, based on feedback linearization to guide an Automatic Guided Vehicle (AGV). The novelty of this work, is the adaptation of a reference trajectory with respect to a desired velocity in real-time to avoid collisions using a time-scaling mechanism. Employing this mechanism, collision avoidance by braking is implemented. Implementation and experimental evaluation of the integrated design of trajectory control, time-scaling and collision avoidance is performed on a real AGV platform.

Abstract

This paper addresses safety indicators for truck platooning at short inter-vehicle distances (with a time gap of 0.5 s). The aim of a safety indicator is to determine the correct moment for initiating a Collision Avoidance brake action to prevent a collision with the preceding truck in threatening situations. Three safety indicators are selected for an evaluation: the intended acceleration of the preceding truck, which is shared via Vehicle-to-Vehicle (V2V) communication, the Brake Threat Number (BTN — based on simple vehicle models and an emergency brake assumption of the lead), and the Time-To-Collision (TTC — based on a constant velocity assumption). The latter two do not rely on V2V communication, but are obtained via on-board signals. Requirements for the amount of false negatives (missing a threatening situation) and the false positives (identifying a safe situation as threatening) are derived from a functional safety perspective. To find thresholds for the safety indicators that minimize the false negative rate, emergency brake tests are used. To evaluate the number of false positives, a set of data of two trucks driving in a platoon at 0.5 s at mixed-traffic highways in Belgium and the Netherlands, collected during 8 hours of automated driving in a platoon, is used. The results indicate that the communicated intended acceleration of the preceding truck might be able to distinguish safe and threatening situations in a vehicle platoon. Furthermore, for situations without V2V, both the BTN and the TTC are not capable to distinguish between threatening and safe situations. The amount of false positives found in the safe driving data-set does not fulfill the requirements derived from functional safety perspective.