Ting Yue

Longitudinal Linear Parameter Varying Modeling and Simulation of Morphing Aircraft

The purpose of this paper is to present linear parameter varying modeling and simulation of a folding-wing morphing aircraft in the wing-folding process. Morphing aircraft can alter the shape to adapt to mission environment changing. When the wing shape is varying, the dynamic responses of the morphing aircraft will be dependent on the time-varying aerodynamic forces and moments, which will be a function of the wing shape change by the morphing command. The folding-wing morphing aircraft is regarded as a variable geometry rigid body, and the six-degree-of-freedom nonlinear dynamic model in the wing-folding process is founded. The decoupled longitudinal dynamic equation of the morphing process is deduced by simplification, and the longitudinal dynamic responses of the wing morphing process are numerically simulated by the quasi-steady aerodynamic assumption. Furthermore, using the Jacobian linearization approach, the longitudinal nonlinear dynamics equations of morphing aircraft are linearized, and the lon...

Multibody Dynamic Modeling and Simulation of a Tailless Folding Wing Morphing Aircraft

The purpose of this paper is to model and simulate a tailless folding wing morphing aircraft in wing folding process. The wing area and other parameters of morphing aircraft largely change when morphing, which will affect the aerodynamic force acting on the aircraft and lead to a variation of movements in the morphing process. The dynamic model of tailless folding wing morphing aircraft in wing folding process was founded and the six-DOF nonlinear equation was deduced. Furthermore, the decoupled longitudinal dynamic equation of morphing process was presented by simplifying. And the result of numeric simulation of aerodynamic force in wing folding process shows that the aerodynamic force is approximate to the steady state. The longitudinal response of morphing process in different wing fold angular velocities was numerically simulated by quasi-steady aerodynamic assumption when taking no account of the unsteady aerodynamic effect in small wing fold angular velocities. And the key factors which affect the dynamical characteristics of morphing process of the tailless folding wing morphing aircraft were investigated by quantity. The research results can be as great reference for the flight control system design in morphing and evaluating the morphing flight safety at low altitude of morphing aircraft.

Flight Performance Characteristics of a Tailless Folding Wing Morphing Aircraft

Morphing aircraft can automatically alter the shape to adapt mission requirement, so that to optimize the flight performance in different flight states. The lift and drag characteristics of a tailless folding wing morphing aircraft in different aerodynamic configurations were analyzed, including unfold, transitional and fold configurations. The typical flight performance of the tailless folding wing morphing aircraft in the three configurations were investigated comparatively, including level flight, climb, cruise, dive, and level turning performances. The superior and inferior of flight performance of the tailless folding wing morphing aircraft in different flight tasks were compared. And the match relationship between optimal aerodynamic configuration and flight tasks was summed up. The results show that the optimal flight performances of morphing aircraft are corresponding to different configurations in different flight tasks. Usually the unfold configuration is adopted in low speed and fold configuration is adopted in high speed. The research results can provide reference to manage the flight performance and improve the fight efficiency of morphing aircraft.

An nonlinear feedback control for radial constrained force of flying boom after contact with receiver

After contact with receiver aircraft, the nozzle of flying boom is locked into the receptacle of receiver which may generate a dangerous radial constrained force (RCF) with disturbance from environment. This paper presents a novel control method to eliminate the RCF. Based on the existing altitude dynamic function, the unloading dynamic model can be achieved by putting the RCF into the existing dynamic function. However the resulting dynamic function is an algebraic equation which has no derivative of the RCF and cannot be used to design unloading controller directly. In order to eliminate the RCF, nonlinear feedback control method is used to obtain the state equation and to design the unloading controller. Due to the particularity of the dynamic function after contact, the Barbalats lemma is used to prove that the control law is asymptotically stable. Finally, the simulation result verifies the effectiveness of the unloading controller.

Attitude control design for flying boom during air-to-air refuelling

Compared with hose-and-drogue refuelling, flying boom refuelling has attracted increasing interest due to its high flow rates and easy contact operation. Aided by a flying boom attitude controller, the boom operator navigates the flying boom into contact with the receptacle of the receiver aircraft. However, disturbances, including tanker wake and atmospheric turbulence, can disturb the motion of the flying boom. In addition, the boom operator requires that the flying boom has good handling qualities to accomplish aerial boom refuelling. To solve the first challenge, a novel back-stepping control approach – back-stepping control driven by a sliding mode disturbance observer – was adopted for attitude control to improve robustness and performance. To address the second challenge, the command filter, which affects the handling qualities, was designed in the attitude control to protect the flying boom from damage. To achieve the desired handling qualities, a mission-oriented method was implemented to determine the filter parameters. Finally, three manoeuvres – yaw tracking, pitch tracking and attitude hold – were calculated to simulate real aerial boom refuelling. The results demonstrate the proposed attitude controller’s effectiveness and robustness.

Dynamic characteristics analysis for oblique wing aircraft

The movement characteristics and control responses of oblique wing aircraft (OWA) are highly coupled between the lonitudinal and lateral-directional axis and presents obvious nonlinearity. This article investigates the dynamic modeling of an OWA, and analyzes its dynamic characteristics. The calculations and simulations show that, OWA can be trimmed by rolling a bank angle and deflecting the triaxial control surfaces in a coordinated way. The oblique wing greatly affects the longitudinal motion. The short-period mode is highly coupled between longitudinal and lateral motion, and the bank angle also occurs in the phugoid mode. However, the effects of oblique wing on the lateral mode shape are relatively small. For the inherent control characteristics, symmetric deflection of horizontal tail will generate not only longitudinal motions but also a large rolling rate. Rolling moment and pitching moment caused by the aileron deflection will reinforce the motion coupling, but the deflection of rudder has relatively little effect on longitudinal motion.

Design of flying boom controller before and after docking

An increasing interest over the last decades in developing aerial boom refueling technology has prompted research into controller design of flying boom. During air-to-air refueling, there are two task for flying boom controller divided by docking respectively: attitude control and unloading control. Under some assumptions, the dynamic models before and after docking are built. Based on the dynamic model before docking, the sliding mode disturbance observer based back-stepping adaptive controller is used in attitude control after dividing the dynamic model into two subsystems. Then, the unloading controller is designed to eliminate the radial constraint force. After designing, the asymptotical stability of unload controller is proved by Barbalats lemma. The effectiveness and adaptability is shown in the results of simulations with complex circumstance of flying boom.