OUT-OF-THE-LOOP PERFORMANCE PROBLEMS AND THE USE OF INTERMEDIATE LEVELS OF AUTOMATION FOR IMPROVED CONTROL-SYSTEM FUNCTIONING AND SAFETY

Human supervisory control and monitoring of automated systems, as well as, passive system(s) information processing can all be classified as forms of out-of-the-loop (OOTL) performance. Whether the operator's t ask to decide if process control intervention is necessary, detect a c ritical system event, or accept or reject the actions of a computer co ntroller, he or she is removed from direct, real-time control of the s ystem. OOTL performance is a critical issue in overall automated syste ms functioning because it is associated with numerous negative consequ ences including: (a) operator failure to observe system parameter chan ges and intervene when necessary (vigilance decrements); (b) human ove r-trust in computer controllers (complacency); (c) operator loss of sy stem or situation awareness; and (c) operator direct/manual control sk ill decay. These consequences have been found to impact human performa nce under both normal operating conditions and system failure modes, w ith a greater effect on the latter [15] leading to serious problems in operator ability to perform their assigned tasks when working with au tomated systems. Level of automation (LOA), has been put forth as an a pproach to ameliorating OOTL performance problems. It is intended to d etermine the optimal assignment of control between a human operator an d computer in order to keep both involved in system operations. LOA co nsiders the capabilities and capacities of both the human and computer controller in determining their optimal coupling. It constitutes a sy stems approach to resolving OOTL performance problems by minimizing th e negative consequences associated with the removal of the operator fr om active system control, and allows for the strengths of both human d ecision making and computer processing to be realized. When compared t o a technological approach that assesses only the capabilities of the computer in allocating as much responsibility to the machine as possib le, and assigning the remaining tasks to the human operator the advant ages can be considerable. A LOA taxonomy will be presented along with research examining its utility in a dynamic control task. Using LOA to identify optimal combinations of human and computer control was found to produce improvements in system performance under intermediate leve ls. These levels involve joint human and computer control of various s ystem functions, such as monitoring, planning, and option selection an d implementation. Results indicated decreases in the number of system processes/tasks overlooked by operators. These improvements may transl ate into cost reductions due to improved operational safety and are an ticipated to be applicable to process control operations.