We Claim:
[Claim 1] A substitution device comprising:
a substitution preparation unit to generate a control value for controlling an output value of a control target device based on an input value, and when a fault occurs in an information processing circuit that outputs the control value generated to the control target device, perform preparation for substituting for the information processing circuit; and
a substitution unit to generate, upon completion of the preparation, an output plan of a control value such that a difference between an actual output value of the control target device and an output value in a scheduled temporal transition gradually decreases, based on the scheduled temporal transition that is a temporal transition of an output value of the control target device, which is scheduled before occurrence of the fault in the information processing circuit, a difference between an actual output value of the control target device upon completion of the preparation and an output value in the scheduled temporal transition, and an input value and a control value before occurrence of the fault in the information processing circuit, and output a control value to the control target device instead of the information processing circuit according to the output plan generated.
[Claim 2] The substitution device according to claim 1, wherein the substitution
unit generates the output plan based on a difference between an actual output value of the control target device at a time when the preparation is completed and an output value in the scheduled temporal transition, which is generated as a result of absence of output of a control value during a period after occurrence of the fault in the information processing circuit until completion of the preparation. [Claim 3] The substitution device according to claim 1, wherein the substitution
unit generates the output plan based on an input value and a control value immediately before occurrence of the fault in the information processing circuit. [Claim 4] An information processing system comprising:
an information processing circuit to generate a control value for controlling an output value of a control target device based on an input value, and outputs the control value generated to the control target device; and
a substitution device to perform preparation for substituting for the information processing circuit when a fault occurs in the information processing circuit, and upon completion of the preparation, generate an output plan of a control value such that a difference between an actual output value of the control target device and an output value in a scheduled temporal transition gradually decreases, based on the scheduled temporal transition that is a temporal transition of an output value of the control target device, which is scheduled before occurrence of the fault in the information processing circuit, a difference between an actual output value of the control target device upon completion of the preparation and an output value in the scheduled temporal transition, and an input value and a control value before occurrence of the fault in the information processing circuit, and output a control value to the control target device instead of the information processing circuit according to the output plan generated. [Claim 5] The information processing system according to claim 4, wherein the
information processing circuit monitors the substitution device for detecting a fault in the substitution device. [Claim 6] A substitution method comprising:
generating a control value for controlling an output value of a control target device based on an input value, and when a fault occurs in an information processing circuit that outputs the control value generated to the control target device, performing
preparation for substituting for the information processing circuit, by a substitution device that substitutes for the information processing circuit; and
upon completion of the preparation, by the substitution device, generating an output plan of a control value such that a difference between an actual output value of
5 the control target device and an output value in a scheduled temporal transition gradually decreases, based on the scheduled temporal transition that is a temporal transition of an output value of the control target device, which is scheduled before occurrence of the fault in the information processing circuit, a difference between an actual output value of the control target device upon completion of the preparation and
) an output value in the scheduled temporal transition, and an input value and a control value before occurrence of the fault in the information processing circuit, and outputting a control value to the control target device instead of the information processing circuit according to the output plan generated.