ELECTRIC POWER STEERING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an electric power steering device capable of smoothly reducing the assist force while effectively providing it even during the fail-safe shift as an abnormality occurs in the system. SOLUTION: A microcomputer 11 comprises a system abnormality detection unit 31 to detect occurrence of a system abnormality, and a DUTY limit value operation unit 32 to operate the DUTY limit valueαto limit the DUTY indicated value Dx when the system abnormality occurs. The DUTY limit value operation unit 32 reduces the DUTY limit valueαas the time is elapsed from the occurrence of the system abnormality. A DUTY indicated value operation unit 23 limits the DUTY indicated value Dx so as to be within a limit range to be regulated by the DUTY limit valueαwith the value of the DUTY ratio corresponding to the grounding electric potential as a reference. COPYRIGHT: (C)2006,JPO&NCIPI