Page - 41 - in Integration of Advanced Driver Assistance Systems on Full-Vehicle Level - Parametrization of an Adaptive Cruise Control System Based on Test Drives

3.1. Full-Vehicle Level vehicle. The major advantages of this method are that the real environmental sensor is usedandsafety-critical situations canbecarriedoutwithoutanyrisk. Thedisadvantage is that the subjective evaluation of probands cannot be performed because there will be no accelerations acting on them. One idea to solve this problem might be to couple the chassis dyno with a moving base driving simulator. The most realistic way to asses ADAS is to conduct test drives in real traffic. The disadvantage is that no defined manoeuvres can be performed, but the results are the most realistic that can be generated, [Bre09]. However, critical situations cannot be assessed. The above mentioned tests on the full-vehicle level are usually subjective evaluations of the probands. These are very important because it is the way a customer would evaluate the system. For the development process, it is very important to use objective measures. Examples are given in [Hol12], [SBB+07] and [BHLSE13]. In his diploma thesis [Hol12], Holl defined a list of manoeuvres which are used to evaluate a vehicle equipped with ACC or Stop-and-Go Adaptive Cruise Control (FSRA). The test driver has to provide subjective evaluations of defined criteria. The vehicle is also equipped with a measurement system, which records such data as the longitudinal vehicle speed and acceleration vvx, vax and, if available, the relative distance and speed to the target vehicle, sr, sr˙. The subjective and objective evaluations lead to an overall assessment in the categories of ˆ function, ˆ comfort, ˆ sensor function, ˆ disturbing noise inside the car, ˆ geometric integration of the sensor(s), ˆ operability and ˆ false positives. The term false positives describes situations in which the system performs an unneces- sary intervention. This might occur when the environmental-recognition sensor detects a ghost object and the ADAS begins to decelerate, leading to dangerous situations, which has to be prevented under all circumstances. Holl’s method helps to compare the behaviour of different systems or different parametrizations of systems in the above- mentioned categories. Despite the attempt to asses the systems in an objective way, the feeling of the test driver influences the output and therefore yields a subjective evalu- ation. This method works very well for comparing systems, but it will not work for absolute evaluation of individual systems. Schrauf et al. described in [SS13] a method for objectively evaluating automated and autonomous driving vehicles. In this method, many test drives with probands are con- ducted and recorded, and each of the probands then evaluates the system’s performance. 41