Control laws that are based on the nonlinear inverse dynamics (NID) of the aircraft offer the potential for providing improved levels of performance over conventional flight control designs. The NID and its application in the flight control during windshear penetration are introduced here. With the employment of a real engineering windshear model and NID, a low‐altitude windshear penetration flight control law is designed. The simulative calculation results indicated that the NID control logic works effectively in the trajectory control of the aircraft during the penetration of windshear.
PurposeThis paper aims to present a theoretical method for analyzing the stability and control of a hingeless helicopter in the presence of windshear.Design/methodology/approachIn this paper, the stability and control of a hingeless helicopter in the presence of windshear are investigated. First, the rotary wing dynamic model considered is the one of flap‐pitch (including the elastic deformation of the control system)‐torsion coupling. The induced velocity nonuniform distribution derived from vortex theory is taken into account. Then, as for atmospheric turbulence, the linear windshear model is used for modeling the variation of wind field. Finally, according to the calculated results of the stability characteristic roots and the control response of the helicopter, the helicopter performance in wind shear field is analyzed, and some conclusions are obtained.FindingsSome useful conclusions are obtained through sample analysis.Research limitations/implicationsAlthough the analyses for stability and control of a hingeless helicopter in the presence of windshear could be obtained using the current method, the model of complex wind field will still be expected in future studies.Practical implicationsA very useful method for analyzing helicopter stability and control.Originality/valueThe proposed method is valid and available for the analysis of helicopter flight dynamics.
Complex weather conditions, especially windshear and icing encounter, have severe effects on aircraft flight safety. The effect of low-altitude windshear and ice accretion on aircraft performance and control has been studied in this paper. With the employment of a windshear model and nonlinear inverse dynamics (NID) method, a low-altitude windshear penetration flight control law is designed. The effect of ice accretion was modeled on the stability and control of an aircraft. Several icing parameters are imported to the small disturbance flight dynamics model to calculate the change of performance, stability and control derivatives between clean and iced aircraft. These derivatives were used to calculate the elevator, the aileron and the rudder step responses to investigate the icing effect.
The simulation results indicate that the NID control logic works effectively in the trajectory control of the aircraft during the penetration of windshear. The method used to study the effect of ice accretion on aircraft is valid and it can provide data for real-time calculation for icing encounter.
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