Reconfigurable Fault-Tolerant Dynamic Control Allocation Against Multiple Effectors Impairment

Abstract There are several fault-tolerant flight controllers (FTFC) to prevent accidents resulting from loss-of-control in-flight (LOC-I). In this work, the State-Dependent Riccati Equation (SDRE) algorithm is utilized as a passive FTFC, whereas the reconfigurable control allocation (CA) method as an active FTFC. The process of CA reconfiguration is thoroughly investigated and introduced for multiple control surface issues. For instance, with moderate turbulence, the left engine fails, the right aileron becomes locked at 20 degrees, and the upper rudder is damaged at the same time. If only weight matrices ( $$W_v$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>W</mml:mi> <mml:mi>v</mml:mi> </mml:msub> </mml:math> , $$W_1$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>W</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:math> , and $$W_2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>W</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:math> ) or steady distribution matrix ( S ) is changed, multiple control surface issues result in loss-of-control in flight. Therefore, in contrast to previous research on the subject, a thorough method of fault-tree-like logic for the reconfiguration is presented for different control surface problems. In this method, weight matrix ( $$W_v$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>W</mml:mi> <mml:mi>v</mml:mi> </mml:msub> </mml:math> ), control effectiveness matrix ( $$B_{ca}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mrow> <mml:mi>ca</mml:mi> </mml:mrow> </mml:msub> </mml:math> ), and steady distribution matrix ( S ) are reconfigured in relation to various types of emergencies. To tune these parts, other weight matrices ( $$W_1$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>W</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:math> and $$W_2$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>W</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:math> ) are also considered. There is a strong relationship between these matrices concerning multiple emergencies. A thorough description of how to modify dynamic control allocation is provided. The proposed system is tested with moderate turbulence. The robustness of the SDRE controller is evaluated with the help of the deteriorated $$B_{ca}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mrow> <mml:mi>ca</mml:mi> </mml:mrow> </mml:msub> </mml:math> matrix. Up to $$50\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>50</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> erroneous parameters for $$B_{ca}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mrow> <mml:mi>ca</mml:mi> </mml:mrow> </mml:msub> </mml:math> , SDRE controller can compensate error. Detailed analyses are given to show the effectiveness of the proposed control architecture for the NASA GTM T-2.