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Sun J.-L.,Nanjing University of Aeronautics and Astronautics | Liu C.-S.,Nanjing University of Aeronautics and Astronautics | Lu K.,Nanjing University of Aeronautics and Astronautics | Lu K.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Shi H.-M.,Nanjing University of Aeronautics and Astronautics
Chinese Control Conference, CCC | Year: 2015

The attitude control is the key of the automatic flight for a quad-rotor aircraft. In order to guarantee the robustness of the quad-rotor aircraft for various uncertainties, a new design method of the robust optimal control that integrates the sliding mode control theory with state-dependent Riccati equation (SDRE) is proposed in this paper. First, the whole attitude kinematical model is obtained. By using the SDRE approach, an optimal control law of the attitude for quad-rotor aircraft without uncertainties is obtained. Then, the sliding mode control theory combing with SDRE is applied to improve the robustness of the quad-rotor aircraft. As a result, the system is robust optimal to the parameters variations or extraneous disturbances and the stability is proved. Finally, the validity and robustness of the proposed algorithm are verified by simulation results. © 2015 Technical Committee on Control Theory, Chinese Association of Automation. Source


Song S.,Beihang University | Wang W.,Beihang University | Lu K.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Sun L.,Beihang University
Proceedings of the 2015 27th Chinese Control and Decision Conference, CCDC 2015 | Year: 2015

A tilt-rotor has a rotor on each side of its airframe and each rotor can be tilted to provide lift or thrust. With the tilt on rotors, the model of tilt-rotor has a significant change. Conventional control methods based on linearized model need extensive gain scheduling with the nacelle angle and flight condition. In order to alleviate this requirement, a design of attitude control based on ESO(Extended State Observer) is developed. The kernel of this method is the estimation and compensation of the disturbance on model. The disturbance includes the model error and coupling between different channels. By the compensation of the disturbance, the controller achieves the decoupling of the system and the compensation of model error and other disturbance at the same time. This control architecture is based on the nonlinear model of the aircraft and the parameters of the controller are available in wide ranges. Nonlinear feedback law is designed for outer loop controller to guarantee the dynamic performances. Simulation results in different flight conditions show that the design of attitude control is feasible. © 2015 IEEE. Source


Ke L.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Wang Z.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Yuan S.,Nanjing University of Aeronautics and Astronautics
2014 IEEE Chinese Guidance, Navigation and Control Conference, CGNCC 2014 | Year: 2015

Automated carrier landing of an Unmanned Air Vehicle is a complex process. To successfully complete the task of landing on carrier, firstly the guidance system should give UAV flight control system a proper landing trajectory, then the flight control system according to the instructions given by the guidance system of UAV make the UAV fly on the right track, finally realizing automatic landing on carrier. In this process the guidance system providing correct guidance signal is a key factor in the success of landing on carrier. Now most aircraft carriers have angled deck, so there are great differences to ground-based landing. In view of this situation, a guidance law is designed for UAV landing on carrier, and the simulation of guidance law is carried out. Because of the air flow disturbance behind of the carrier, the requirement of flight control system is robust, so, this paper introduces quantitative feedback robust control design method to design the flight controller, in order to guarantee the robustness of control system. The results show that the guidance law and flight control system designed in this paper could realize the UAV autonomous landing. © 2014 IEEE. Source


Huang S.-L.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Zhao Q.-J.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Zhao Q.-J.,Nanjing University of Aeronautics and Astronautics | Xu G.-H.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Xu G.-H.,Nanjing University of Aeronautics and Astronautics
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2011

An iterative free-wake computational method has been developed for the prediction of aerodynamic interaction characteristics between the twin rotors of a tandem helicopter. In this method, the mutual interaction effects among the rotor and wake as well as the wake and wake are included, and a rotor wake model, blade aerodynamic model and rotor trim model are coupled to solve the aerodynamic force and momentum of twin rotors. A new dual-rotor trim method has been given so as to be suitable for the aerodynamic interaction calculation of tandem twin rotors. By the method, the distribution of velocity and the rotor performance on a tandem twin-rotor at the condition of interactions are calculated, and the comparisons with the available experimental data are also made to show the capability of the present method. Then, the effects of such parameters as the longitudinal spacing and axial spacing between twin rotors are emphatically analyzed. As a result, the performance of both front and rear rotors is slightly worse than that of single rotor in hover. Furthermore, the effects of such parameters as the longitudinal separation and axial separation between twin rotors are emphatically analyzed. The results show that the tandem rotors need 8.5% additional power compared to single rotor when the longitudinal separation is 1.3R, and with the longitudinal separation increases, the additional power are reduced. The additional power is minimum when the longitudinal separation is 1.85R. Source


Wu H.-D.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Tang Z.-F.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Tang M.,Science and Technology on Rotorcraft Aeromechanics Laboratory
American Helicopter Society International - 2nd Asian/Australian Rotorcraft Forum, ARF 2013 and the 4th International Basic Research Conference on Rotorcraft Technology 2013, IBRCRT 2013 | Year: 2013

In this article, a numerical simulation method for the unsteady fanwing flowfield has been established by solving the N-S equations, based on the eccentric vortex exist inside fanwing. The aerodynamic characteristics of funwing under different state have been numerical simulation by using this method. The eccentric vortex inside fanwing have been discussed through the calculation results. Source

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