Constrained Active Fault Tolerant Control Based on Active Fault Diagnosis and Interpolation Optimization

Area of Science:

• Control Engineering
• System Safety
• Fault Diagnosis

Background:

• Component and actuator faults pose significant risks to system performance and safety.
• Existing fault tolerant control (FTC) methods often struggle with state and input constraints, leading to computational burdens.
• The need for efficient and robust fault diagnosis and control reconfiguration is critical for complex systems.

Purpose of the Study:

• To propose a new active fault tolerant control (FTC) scheme that effectively addresses component/actuator faults in systems with state and input constraints.
• To enhance diagnostic efficiency through an active fault diagnosis approach using a single activated observer.
• To reduce computational effort compared to traditional constrained predictive FTC methods.

Main Methods:

• Active fault diagnosis using offline-designed diagnostic observers, auxiliary signals, and separation hyperplanes.
• Online fault detection and isolation using a single activated diagnostic observer.
• Active fault tolerant control comprising offline-determined inner FTC, online-determined outer FTC, and a linear-programming-based interpolation algorithm.
• Integrated design of inner FTC and diagnostic observers to mitigate estimation and control error interactions.
• Soft constraint method for handling constraint violations.

Main Results:

• The proposed scheme achieves efficient fault detection and isolation with reduced diagnostic overhead.
• Online control reconfiguration is enabled through an interpolation algorithm that optimizes the combination of inner and outer FTC.
• The method significantly reduces computational requirements compared to conventional constrained predictive FTC.
• Integrated design successfully suppresses robust interaction influences between estimation and control errors.
• Validation through a case study on a wastewater treatment plant model demonstrates effectiveness.

Conclusions:

• The developed active fault tolerant control scheme provides an efficient and computationally reduced solution for systems with constraints and component/actuator faults.
• The integrated active fault diagnosis and FTC approach enhances system safety and reliability.
• The method's effectiveness is confirmed in practical applications, such as wastewater treatment plants.