Industrial cost-benefit assessment for fault tolerant control systems

Economic aspects are decisive for industrial acceptance of research concepts including the promising ideas in fault tolerant control. Fault tolerance is the ability of a system to detect, isolate and accommodate a fault, such that simple faults in a subsystem do not develop into failures at a system level. In a design phase for an industrial system, possibilities span from fail safe design where any single point failure is accommodated by hardware, over fault-tolerant design where selected faults are handled without extra hardware, to fault-ignorant design where no extra precaution is taken against failure. The paper describes the assessments needed to find the right path for new industrial designs. The economic decisions in the design phase are discussed: cost of different failures, profits associated with available benefits, investments needed for development and lifetime support. The objective of this paper is to help, in the early product development state, to find the economical most suitable scheme. A salient result is that with increased customer awareness of total cost of ownership, new products can benefit significantly from applying fault tolerant control principles