EPS Assist Control During Idle-Stop Communication Failure

The system divides the control function into two independent parts: the IS controller manages idle-stop operations using its own diagnosis results, while the EPS controller manages steering assist using its own diagnosis results. This segmentation allows each controller to operate independently based on available information, resolving the contradiction by enabling idle-stop to continue even when communication between controllers is interrupted.

Each controller performs self-diagnosis and self-decision making regarding idle-stop operations. The IS controller uses its own diagnosis results to determine whether to permit idle-stop, rather than relying on the EPS controller's diagnosis results or communication with it. This self-service approach ensures idle-stop can continue operating independently even when communication is interrupted.

The diagnosis functions are segmented between two controllers: the EPS controller performs voltage error diagnosis using a low threshold during cranking, while the IS controller performs its own separate diagnosis to determine idle-stop permission. This segmentation prevents the EPS controller's conservative diagnosis from incorrectly prohibiting idle-stop, as the IS controller makes the final decision based on its own diagnosis results.

The IS controller acts as an intermediary that receives and processes diagnosis information independently. Rather than the EPS controller directly prohibiting idle-stop based on its voltage error diagnosis, the IS controller uses its own diagnosis results to make the permission decision, serving as a mediator that prevents incorrect prohibitions while maintaining reliable voltage error detection capability.