What Is Fault Detection, Isolation, and Recovery (FDIR)?

Fault detection, isolation, and recovery (FDIR) logic ensures your control system is robust against faults and other abnormal conditions.

FDIR involves:

• Detecting faults, such as a sensor failure or physical component malfunction
• Isolating the source of the anomaly
• Recovering from the fault and mitigating its effect on the system

Model-Based Fault Detection

Model-based fault detection logic within FDIR uses a simplified system model to determine when a fault occurs. The real-time behavior of a specific component is compared against modeled performance. Other techniques include the use of logic that determines when a signal exceeds physical limits.

Isolation

Isolation logic within FDIR diagnoses the specific nature of a detected fault. Isolation techniques include the use of system redundancy to determine which redundant component’s behavior deviates from that of identical components.

Recovery

Recovery logic within FDIR ensures the system does not enter an unsafe state in the presence of a detected fault and attempts to regain correct behavior of the faulted component. Recovery techniques include reversion to a safe operating mode, switching to a backup system, reconfiguring the system, or resetting the faulted component.

FDIR Using Model-Based Design

You can design and test your FDIR logic using Simulink^®. You can model fault detection and isolation logic using Simulink to determine when a fault has occurred. You can use Stateflow^® to implement recovery logic by commanding the system to enter a safe mode.

You can use Simulink Fault Analyzer™ to inject faults on Simulink signals to test your FDIR logic. You can manage faults modeled across multiple domains, such as those modeled using Simulink, Simscape™, and System Composer™.