Advanced robots for the nuclear power plant maintenance are increasing the complexity in comparison with industrial robots, and severe in condition of use, and are increasing the importance of safety and reliability.
In this paper, as a high reliability technology for Advanced Robot, Functional Failsafe control (FFC) is described.
FFC isolates the faults, and keeps the minimum function of robot, using the remained potential redundancy of robot, with minimizing of additional parts to robot, at the occurrence of faults.
We suggest the three reliability evaluation principles for Advanced robot, then define the FFC in these principles.
In the proposed FFC, the method of using an amplifier between two servosystems in common, and the method of stucking the degrees of freedom of robot arm are studied and proved by experiments on the design of FFC. And, a new design method is showed, based on not only the reliability of time, but also the reliability of amount of working.
So, we clarified some remained subjects to develop for the FFC.