This paper discusses some aspects of function allocation to human and/or machine in the context of collision avoidance. Function allocation determines both the system performance, and the quality of the work situation as experienced by the human operator. Some system design criteria important for the function allocation are: (1) user acceptance; (2) technological constraints; (3) safety aspects; and (4) costs. The paper illustrates how the system design criteria can be specified in more detail by showing an example for the criteria for the acceptance of new systems by the automobile user. The collision avoidance function can be differentiated into various subfunctions. These include for instance: (i) perception of the relevant objects and their characteristics in the scene; and (ii) continuous updating of the effectiveness of both the chosen action(s) and decisions made about the additional or correcting measures. The subfunctions have to be performed independently from the assignment of the collision avoidance function to man and/or machine. Important conclusions are: (a) achieving both improvements of active safety and the user acceptance requires a thorough function allocation process; (b) function allocation must be understood as the prime system engineering task; and (c) sometimes conflicting system design criteria will only allow to find the best compromise.
Abstract