Fault-Tolerant Control of Deterministic Input/Output Automata
Melanie Schuh
Cite this publication as
Melanie Schuh, Fault-Tolerant Control of Deterministic Input/Output Automata (2017), Logos Verlag, Berlin, ISBN: 9783832592844
Descripción / Abstract
This thesis deals with active fault-tolerant control of discrete event systems modeled by deterministic Input/Output (I/O) automata. Active fault-tolerant control realizes three operating modes -- nominal control, fault diagnosis and controller reconfiguration. A new fault-tolerant controller which autonomously ensures the fulfillment of the control aim, both, in the faultless and the faulty case is developed. The control aim is to steer the plant into a desired final state while guaranteeing the avoidance of illegal transitions.
Corresponding to the three operating modes, the proposed integrated fault-tolerant controller consists of a tracking controller, a diagnostic unit and a reconfiguration unit. As long as no fault is present, the tracking controller controls the plant in a feedback loop in order to guarantee the fulfillment of the control aim. At the same time the diagnostic unit detects whether a fault occurred. If a fault is detected, a novel active diagnosis method is used in order to identify the present fault as well as the current state of the faulty plant. The reconfiguration unit uses the diagnostic result provided by the diagnostic unit to reconfigure the tracking controller. As a main result, it is proved that the plant in the fault-tolerant control loop fulfills the control aim in the faultless as well as in the faulty case if the control loop is recoverable. The applicability of the fault-tolerant control method is demonstrated by means of a handling process at the Handling System HANS.
Corresponding to the three operating modes, the proposed integrated fault-tolerant controller consists of a tracking controller, a diagnostic unit and a reconfiguration unit. As long as no fault is present, the tracking controller controls the plant in a feedback loop in order to guarantee the fulfillment of the control aim. At the same time the diagnostic unit detects whether a fault occurred. If a fault is detected, a novel active diagnosis method is used in order to identify the present fault as well as the current state of the faulty plant. The reconfiguration unit uses the diagnostic result provided by the diagnostic unit to reconfigure the tracking controller. As a main result, it is proved that the plant in the fault-tolerant control loop fulfills the control aim in the faultless as well as in the faulty case if the control loop is recoverable. The applicability of the fault-tolerant control method is demonstrated by means of a handling process at the Handling System HANS.
Índice
- BEGINN
- Introduction
- Fault-tolerant control
- Literature on fault-tolerant control of discrete event systems modeled by automata
- Main contributions of the thesis
- Structure of the thesis
- Formalization of the fault-tolerant control problem
- Notation
- Deterministic I/O automata
- Plant models
- Problem statement
- Running example: Automated warehouse
- Tracking control of deterministic I/O automata
- Controllability analysis
- Structure of the tracking controller
- Controller for tracking a reference trajectory
- Planning a reference trajectory
- Fulfillment of the control aim in the closed-loop system
- Complexity of the tracking control method
- Active fault diagnosis
- Consistency-based fault diagnosis settings
- Testing deterministic I/O automata
- Diagnosability analysis
- General approach for the fault diagnosis
- Generation of input sequences for active diagnosis
- Properties of the diagnostic result
- Complexity of the fault diagnosis methods
- Active diagnosis avoiding illegal transitions
- Reconfiguration of the tracking controller
- Reconfiguration setting
- Reconfiguration with unambiguous diagnostic result
- Reconfiguration with ambiguous diagnostic result
- Integrated fault-tolerant control method
- Fault-tolerant control flowchart
- Fault-tolerant control without illegal transitions
- Safe fault-tolerant control
- Example: Fault-tolerant control of a manufacturing process
- Handling system HANS
- Models of the Handling System HANS
- Behavior in the faultless case
- Recoverability analysis
- Fault-tolerant control with unambiguous diagnostic result
- Fault-tolerant control with ambiguous diagnostic result
- Safe fault-tolerant control
- Conclusion
- Summary
- Outlook
- Bibliography
- Appendices
- List of symbols
- Compatibility partitions of the automated warehouse
- Models of Handling System HANS