On threat assessment and collision avoidance for articulated machinery in low-speed scenarios

This paper investigates the hypothesis that threat assessment algorithms, developed for passenger cars and modified for articulated vehicles in low-speed scenarios, can be used to avoid a majority of the collision accidents in construction environments. The effect of using a collision avoidance system on a Volvo A25 hauler is investigated in several simulated scenarios with stationary obstacles. It is concluded that the safety benefit is severely limited by the relatively low braking capacity of the machine. Due to the limited capacity, braking manoeuvres must be initiated rather early, therefore steering is more efficient in many situations. Moreover, collisions are difficult to avoid when there is an offset between the machine and obstacle which is likely to occur in unstructured environments. The effect of different driving styles is also analysed and adapting the collision avoidance function to the individual driver can increase the number of collisions prevented. Another possible way to increase the safety benefit is to introduce a safety margin around obstacles. Both these options, however, increase the risk for generating false alarms.