Functional Demonstrator of a Preventive Pedestrian Protection System

3 Functional Demonstrator of a Preventive Pedestrian Protection System 

A functional demonstrator of a preventive pedestrian system is studied within this thesis. The functions of the vehicle-based system are best explained using the phases of an accident as given in Fig. 1.2 (p. 4). The preventive system is described by an operational model. An operational model describes the relevant functional behavior of system components independently of the precise engineering implementation. The general escalation strategy before a crash is the following  

If a pedestrian is detected by the system, the physically possible trajectories of the vehicle and the pedestrian are calculated during interpretation and evaluation of the situation. The possible future trajectories for the vehicle (depending on current speed, maximum steering angle, friction, and acceleration capabilities) define a spatial region wherein the vehicle can reach every point within a given time span (different methods of calculation are explained in [8]). 

If a Specific collision probability is exceeded, the system decides to act and gives the appropriate feedback. The decision of the system is rule-based. Bases are the prediction of the movements of the two participants and the predicted collision probability. The system can have three different categories of states  

Recognizable by the driver pre-warning, warning or automatic braking. 

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A new approach to evaluation of active safety is then developed in Chap. 3. The process, including information needed, is described, and the prerequisites are defined. In detail, accident scenarios, configuration of a functional demonstrator of a preventive pedestrian protection system, and the simulative technique required are described. An introduction of a metric for the quantification of the change in safety rounds up the method. 

The process chain starts with a reference scenario for the situation in question. For example, in the case of pedestrian protection, the most important scenario is a pedestrian crossing from the right in an urban setting (for Germany and the US). A functional demonstrator of a preventive pedestrian protection system is defined to test the process chain with a measure of active safety. The system detects the pedestrian, warns the driver, preconditions the brake assist, and as a last resort brakes automatically. 

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