Interval type-2 TS fuzzy model for angle of attack sensor of the aircraft

Abstract

This paper presents an interval type-2 Takagi Sugeno (TS) fuzzy model of Angle of Attack sensor of the aircraft. The angle of attack signal is used as a gain scheduling variable in flight control computer for governing the flight control laws, hence any failure or malfunction of this sensor can cause catastrophic damage of the aircraft. In this paper angle of attack signal is estimated indirectly by means of interval type-2 TS fuzzy model with the data obtained from aircraft speed, vertical acceleration and pitch angle sensors. The methodology shows its benefits for formulating a data driven standby model of actual angle of attack sensor. The presence of uncertainty in data or measurements can be addressed by type-2 fuzzy logic theory. The concept is demonstrated by using the recorded flight data of VFW-614 ATTAS aircraft operating in quasi-steady stall flight maneuver without any reference to physics of stall hysteresis. The model parameters are obtained using Gustafson and Kessel (G-K) clustering and weighted least square method. The comparative study with other modeling methods and fivefold cross validation test between model estimated data and actual angle of attack sensor data shows well suited modeling capability of proposed interval type-2 TS fuzzy system.