A design methodology for a self-maintenance machine

Traditional design for reliability is not perfect, because such systems aim at less faults but once a fault happens they hard-fail. To prevent such disasters, one should develop soft-fail machines that can still maintain their functions even if faults happen. The authors propose a framework of a self-maintenance machine (SMM). Two repair strategies are proposed; viz., control type and functional redundancy type that is a strategy to add redundancy to a machine by using potential functions of existing parts. For executing fault diagnosis and repair planning, a model based approach that employs qualitative physics, is proposed. Finally, they illustrate two prototypes of SMM; the control type and the functional redundancy type