Content deleted Content added
Adding short description: "Approach in control theory to achieve fault-tolerant control for dynamic systems" |
|||
| (4 intermediate revisions by 4 users not shown) | |||
Line 1:
{{Short description|Approach in control theory to achieve fault-tolerant control for dynamic systems}}
'''Control reconfiguration''' is an active approach in [[control theory]] to achieve [[Fault-Tolerant Control|fault-tolerant control]] for [[dynamic systems]].<ref>{{Harv|Blanke|Kinnaert|Lunze|Staroswiecki|2006}}</ref> It is used when severe [[Fault (technology)|faults]], such as actuator or sensor outages, cause a break-up of the [[control loop]], which must be restructured to prevent [[failure]] at the system level. In addition to loop restructuring, the [[Controller (control theory)|controller]] parameters must be adjusted to accommodate changed plant dynamics. Control reconfiguration is a building block toward increasing the [[dependability]] of systems under [[feedback]] control.<ref>{{Harv|Patton|1997}}</ref>
Line 7 ⟶ 8:
=== Fault modelling ===
The figure to the right shows a plant controlled by a controller in a standard control loop.
The nominal linear model of the plant is
Line 19 ⟶ 20:
\mathbf{y}_f & = \mathbf{C}_f\mathbf{x}_f\end{cases}</math>
where the subscript <math>f</math> indicates that the system is faulty. This approach models multiplicative faults by modified system matrices. Specifically, actuator faults are represented by the new input matrix <math>\mathbf{B}_f</math>, sensor faults are represented by the output map <math>\mathbf{C}_f</math>, and internal plant faults are represented by the system matrix <math>\mathbf{A}_f</math>.
The upper part of the figure shows a supervisory loop consisting of ''fault detection and isolation'' (FDI) and ''reconfiguration'' which changes the loop by
Line 43 ⟶ 44:
# State trajectory recovery
# Transient time response recovery
Internal stability of the reconfigured closed loop is usually the minimum requirement. The equilibrium recovery goal (also referred to as weak goal) refers to the steady-state output equilibrium which the reconfigured loop reaches after a given constant input. This equilibrium must equal the nominal equilibrium under the same input (as time tends to infinity). This goal ensures steady-state reference tracking after reconfiguration. The output trajectory recovery goal (also referred to as strong goal) is even stricter. It requires that the dynamic response to an input must equal the nominal response at all times. Further restrictions are imposed by the state trajectory recovery goal, which requires that the state trajectory be restored to the nominal case by the reconfiguration under any input.
Line 54:
=== Fault hiding ===
[[Image:FaultHiding with Goals.png|frame|Fault hiding principle. A reconfiguration block is placed between faulty plant and nominal controller. The
This paradigm aims at keeping the nominal controller in the loop. To this end, a reconfiguration block can be placed between the faulty plant and the nominal controller. Together with the faulty plant, it forms the reconfigured plant. The reconfiguration block has to fulfill the requirement that the behaviour of the reconfigured plant matches the behaviour of the nominal, that is fault-free plant.<ref>{{Harv|Steffen|2005}}</ref>
Line 99:
== Further reading ==
* {{Citation
|
| last3=Lunze | first3=J. | last4=Staroswiecki | first4=M.
| year= 2006 | edition=2nd
Line 112:
| publisher=IFAC | place=Prague, Czech Republic}}
* {{Citation
|
| last3=Steffen | first3=T. | year=2003
| chapter=Control Reconfiguration Demonstrated at a Two-Degrees-of-Freedom Helicopter Model
| title=Proceedings of European Control Conference (ECC) | place=Cambridge, UK.}}
* {{Citation
|
| chapter=MPC Fault-Tolerant Flight Control Case Study: Flight 1862
| title=
| publisher=IFAC | place=Washington D.C., USA | pages=265–276}}
* {{Citation
|
| last3=Zhang | first3=Y. | year= 2003
| title=Active Fault Tolerant Control Systems - Stochastic Analysis and Synthesis
| publisher=Springer}}
* {{Citation
|
| chapter=Bibliographical review on reconfigurable fault-tolerant control systems
| title=
| publisher=IFAC | place=Washington D.C., USA | pages=265–276}}
* {{Citation
Line 145:
| journal=IEEE Control Systems Magazine
| title=Intelligent fault diagnosis and control reconfiguration
| volume=14 | number=3 | pages=6–12 | doi=10.1109/37.291462| s2cid=39931526 }}
* {{Citation
|
| year= 1991 | journal=International Journal of Control
| title=Stability of the pseudo-inverse method for reconfigurable control systems
| volume=53 | number=3 | pages=717–729 | doi=10.1080/00207179108953643}}
* {{Citation
|
| last3=Eterno | first3=J.S. | last4=Barrett | first4=N.M.
| year= 1985 | journal=IEEE Control Systems Magazine
| title=An Automatic Redesign Approach for Restructurable Control Systems|volume=5
| number=2 | pages=16–22 | doi=10.1109/mcs.1985.1104940| s2cid=12684489 }}.
* {{Citation
|
| last3=Yazdanpanah | first3=M. J. | year= 2005
| journal=International Journal of Control
| title=Reconfigurable control system design using eigenstructure assignment: static, dynamic and robust approaches
| volume=78 | number=13 | pages=1005–1016 | doi=10.1080/00207170500241817| s2cid=121350006 }}.
[[Category:Control theory]]
| |||