Segmented Wing Aircraft Lateral Directional Flight Control Design With Minimum Drag Constraints

Author(s):  
Frank R. Chavez ◽  
Jerry Vogel

Following the current trend for developing biologically inspired flight configurations, flight control system for a transport type aircraft with no vertical tail and segmented main wing is to be developed. The transport configuration is inspired by the fact that birds do not have vertical tails and their wings have various trailing edge feathers that serve to form independent wing segments for roll and yaw control. An aerodynamic model for a generic transport aircraft, modeled after the Boeing 747, is obtained using NASA’s PMARC software. The aircraft is modeled with no vertical tail and the main wing has several independently controlled trailing edge segments. A flight control design will be carried out to satisfy roll and yaw moment commands. These moment commands might come from desired roll or yaw rate commands from the pilot. In addition, for increased performance, it is desirable to maintain a minimum drag configuration. This will result in a reduction in fuel usage for maximum range, endurance, or maximum flight speed. The final controller will provide main wing segment deflection commands designed to meet desired roll and yaw moment commands while attaining a minimum drag configuration.

Author(s):  
Ziyang Zhen ◽  
Ju Jiang ◽  
Xinhua Wang ◽  
Kangwei Li

This paper addresses the problems of modeling, control design, and influence analysis of the steam catapult-assisted take-off process of the carrier-based aircrafts. The mathematical models of the carrier-based aircraft, steam catapult, landing gears, and the environmental factors including deck motion and bow airflow have been established to express the aircraft dynamics in the take-off process. An engineering method based automatic flight control system has been designed, which is divided into the longitudinal channel and lateral channel. The influences of the preset control surface, ship deck motion, ship bow airflow, and automatic flight control system system are tested by a series of simulations. The simulation results show that the elevator angle preset is necessary in the stage of accelerated running on the ship deck and the deck motion is the most important factor for safe take-off, while the ship bow airflow is beneficial for climbing up of the aircraft. The automatic flight control system gives the guarantee of safety and performance in the take-off process of the carrier-based aircraft.


1997 ◽  
Vol 119 (3) ◽  
pp. 588-590
Author(s):  
Wen-Hua Chen

This Technical Brief addresses the problem of robust pole assignment for uncertain dynamic systems. A control design methodology is proposed to determine a fixed controller assigning all poles of uncertain systems in a pre-specified disk. The robust pole assignment problem is reduced to a convex optimization problem. The proposed method is applied in design of a flight control system for a small aircraft successfully.


Author(s):  
Vincenzo Muscarello ◽  
Giuseppe Quaranta

This paper investigates structural coupling problems for tiltrotors, considering not only the interaction of the flight control system with the flexible structure but also the potentially adverse effects on the aeroservoelastic stability that may be caused by the pilot's involuntary, high-frequency, biodynamic response. The investigation is focused on the analysis of the side effects that could appear at high speed in the airplane flight regime, where the whirl flutter boundaries may be significantly reduced. A detailed tiltrotor model, representative of the Bell XV-15 and of a flight control system has been built and joined with a pilot biodynamic model acting on the power-lever and on the center stick, available in the literature. Additionally, a modified version of the XV-15 using differential collective pitch for yaw control in airplane mode instead of rudder has been investigated to show the effect of different yaw control designs.The stability analyses presented demonstrate that the structural coupling analysis and the flutter boundaries for tiltrotors must be evaluated not only considering the closed loop created by the flight control system but also the effect of involuntary pilot response. Sensitivity analyses examine the most critical parameters impacting tiltrotor aeroservoelastic stability. Finally, the employment of notch filters as a means of prevention is discussed.


2018 ◽  
Vol 71 (5) ◽  
pp. 1231-1246 ◽  
Author(s):  
Chen Lu ◽  
Rong-Bing Li ◽  
Jian-Ye Liu ◽  
Ting-Wan Lei

A novel synthetic air data estimation method without using air data sensors is presented, and the method only relies on the information from the Navigation System (NS) and Flight Control System (FCS). The aircraft's aerodynamic model is also required to make a connection between the FCS control parameters and the NS measurements. The airspeed, angle of attack and sideslip, angular velocity and wind speed are defined as state vectors, and state equations are established through the aircraft's aerodynamic model and dynamics. Linear velocity and angular velocity provided by the navigation system are considered as the measurement vector. To deal with variable wind fields, a novel Initialised Three-step Extended Kalman Filter (ITEKF), which considers the wind speed as an unknown input, is developed to track the variation of wind speed. Simulation results based on a Generic Hypersonic Vehicle (GHV) model are presented and compared with an existing method. Factors affecting the method's accuracy include the navigation system accuracy and the aerodynamic model error, are also discussed.


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