Fault tolerance design for computers used in humanoid robots

Although the performance of humanoid robots is rapidly improving, very few dependability schemes suitable for humanoid robots have been presented thus far. In the future, various tasks ranging from daily chores to safety-related tasks will be carried out by individual humanoid robots. If the importance of the tasks is different, the required dependability will also vary accordingly. Therefore, for mobile humanoid robots operating under power constraints, fault tolerance that dynamically changes based on the importance of the tasks is desirable because fault-tolerant designs involving hardware redundancy are power intensive. This paper proposes a task-based dynamic fault tolerance scheme and a duplex computer system that is characterized by performing safety failover when the standby computer unit is in a cold standby state. Moreover, this paper presents the hardware design of the redundancy controller in which the safety failover subsystem is implemented.