The UN Regulation No. 79 is going to be amended to allow automatically commanded steering functions (ACSF) at speeds above 10 km/h. Hence, requirements concerning the approval of automatically performed steering manoeuvres have to be set in order to allow safe use of automatic steering on public roads as well as improve overall road safety for the driver and the surroundings.
By order of the German Federal Ministry of Transport and Digital Infrastructure (BMVI), BASt developed and verified physical test procedures for automatic steering to be implemented in UN Regulation No. 79. The usability of currently available test tools was examined. The paper at hand describes these test procedures and presents results from verification tests.
The designated tests are divided in three sections: functionality tests, verifications for the transition of control and emergency tests. System functionality tests are automatic lane keeping, automatic lane change and an automatic abort of an initiated lane change due to traffic. Those tests check if the vehicle remains in its lane (under normal operating conditions), is able to perform safe automatic lane change manoeuvres and if it considers other road users during its manoeuvres. Transition tests examine the vehicle's behaviour when the driver fails to monitor the system and in situations when the system has to hand over the steering control back to the driver. For instance these tests provoke driver-in-the-loop requests by approaching system boundary limitations, like missing lane markings, surpassing maximum lateral acceleration in a bend or even a major system failure. Even further the driver and his inputs are monitored and if the system detects that he is overriding system actions or contrary want to quit the driving task and unfastens the seat belt, it has to shut down and put the human back into manually control and the responsibility of driving. The last series of test consists of two emergency situations in which the system has to react to a time critical event: A hard decelerating vehicle and a stationary vehicle in front both with no lane change possibility for the ACSF vehicle.
Some of the tests, especially the emergency manoeuvres, require special target vehicles and propulsion systems. Since no fully automatic steering vehicles are available, a current Mercedes E-Class with Mercedes' ‘drive pilot’ system was used. It was shown that the vehicle is automatically able to brake to a full stop towards a static Euro NCAP target from partial-automatic driving at 90 km/h, that it could brake towards a rapidly decelerating lead vehicle when travelling at 70 km/h, that it was able during partially automatic driving to remain in its lane in normal operation conditions and to perform a automatic (driver initiated) lane change while surveilling the driver’s activities.