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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.


Pan Z.,Beihang University | Wang W.,Beihang University | Xiong S.,Beihang University | Lu K.,Science and Technology on Rotorcraft Aeromechanics Laboratory
Proceedings of the 28th Chinese Control and Decision Conference, CCDC 2016 | Year: 2016

To control a slide to turn (STT) missile which attacks a ground moving target in the presence of input saturation, a three dimensional (3D) integrated guidance and control (IGC) law based on dynamic surface control and linear extended state observer (LESO) techniques is developed. Firstly, a novel 3D IGC model is built without assuming that the angle between line of sight (LOS) and missile velocity is small or almost constant. Then, to analyze the effect of input saturation, a Nussbaum function, a smooth tangent function, and an auxiliary system are introduced. The modeling error, acceleration of target and aerodynamic parameters perturbation are viewed as the overall system uncertainty which three linear extended state observers are designed to estimate. With the signal generated by the auxiliary system and uncertainty estimated from LESO, a robust controller utilizing dynamic surface control technique is designed to track the target. Besides, the stability of system is proved. Simulation results demonstrate the effectiveness of the law. © 2016 IEEE.


Lu K.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Lu K.,Nanjing University of Aeronautics and Astronautics | Liu C.,Nanjing University of Aeronautics and Astronautics | Wang Z.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Wang W.,Beihang University
Proceedings of the 28th Chinese Control and Decision Conference, CCDC 2016 | Year: 2016

In this paper, a flight dynamics model of a tiltrotor aircraft is developed used basic equations of motion. This model focuses on control aspect of tiltrotor and is able to show inherent tiltrotor characteristics; then a flight control system is designed used novel L1 adaptive control theory. The XV-15 tilt rotor aircraft is taken as an example to verify this modeling method and flight control system; finally, numerical simulations are presented to show the performance and robustness of the proposed controller. © 2016 IEEE.


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.


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.


Ke L.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Ke L.,Nanjing University of Aeronautics and Astronautics | Liu C.-S.,Nanjing University of Aeronautics and Astronautics | Wang Z.-Z.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Cheng Q.-Y.,Science and Technology on Rotorcraft Aeromechanics Laboratory
Proceedings of the 2015 27th Chinese Control and Decision Conference, CCDC 2015 | Year: 2015

For the problem of attitude control during UAV envelope flight, the parameter uncertainty in full envelope flight was treated as a model uncertainty robustness problem. This paper select the UAV pitch angle as the control object. In order to guarantee the robust performance of the control system, height from 500m to 1000m and speed from 80m/s to 220m/s, we chose 18 trim points, so we have 18 transfer functions of the pitch channel. Next we design a flight controller for all transfer functions. To make the closed loop transfer function meet all the desired performance requirements, the composite bounds on the Nichols chart were generated with the frequency domain specifications converted from desired time domain specifications of flight control system and the design of the pre-filter and the controller was performed by loop shaping. Simulation shows that the controller has a good robust performance. © 2015 IEEE.


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.


Huang S.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Lin Y.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Fan F.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Liu Z.,Science and Technology on Rotorcraft Aeromechanics Laboratory
Transactions of Nanjing University of Aeronautics and Astronautics | Year: 2015

An iterative free-wake computational method is developed for the prediction of aerodynamic interaction characteristics between the twin rotors of a tandem helicopter. Here the mutual interaction effects between twin rotors are included, as well as those between the rotor and wake. A rotor wake model, blade aerodynamic model and rotor trim model are coupled during the process of solution. A new dual-rotor trim approach is presented to fit for the aerodynamic interaction calculations between tandem twin rotors. By the present method, the blade aerodynamic loads and rotor performance for the twin rotors under the interactional condition are calculated, and the comparisons with available experimental data are also made to indicate the capability of the proposed method. Then, the effects of such parameters as the longitudinal separation and axial separation between twin rotors on the aerodynamic interaction characteristics are analyzed. Based on the investigation, the conclusions are obtained to be of benefit to the configuration design of tandem rotors. Furthermore, the performance comparison between the tandem rotors and a single rotor is conducted. It is shown that the strongest interaction does not appear in a hover state, but in a low-speed forward flight state. ©, 2015, Nanjing University of Aeronautics an Astronautics. All right reserved.


Huang S.-L.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Lin Y.-F.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Huang J.-P.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Li M.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Liu P.-A.,Science and Technology on Rotorcraft Aeromechanics Laboratory
Kongqi Donglixue Xuebao/Acta Aerodynamica Sinica | Year: 2012

The current rotor rig for single rotor test is modified for the experiment of tandem twin rotors. By the PIV technique, the measurements on the rotor blade-tip vortices for tandem rotors in both hover and forward flight have been carried out. The interactions between the twin rotors and their influences on blade-tip vortices are investigated by altering the longitudinal and axial distances between the twin rotors and thus changing the overlapping area. It is shown that the axial displacement of the tip vortex gradually increases with the longitudinal distances between the two rotors in hover, but the change of radial displacement of the tip vortex is not the same, and it reaches the minimum value when the longitudinal distance is about equal to 1.8R. On the other hand, when the axial distance between the two rotors is modified, the tip-vortex displacement in axial and radial directions are also changed, but the changs are smaller.


Guo J.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Song Y.,Science and Technology on Rotorcraft Aeromechanics Laboratory | Xia P.,Science and Technology on Rotorcraft Aeromechanics Laboratory
Nanjing Hangkong Hangtian Daxue Xuebao/Journal of Nanjing University of Aeronautics and Astronautics | Year: 2011

The dynamical mathematical flight model of unmanned tilt rotor aircraft is established. The model fusion concept is adopted and the all equinoctial points responses are obtained by using the nonlinear method based on the limited trim points linear model. Therefore, the resolution of the tilt rotor flight dynamics and a multi-model sets are obtained. Furthermore, the study of the rate decouple of MIMO system based on the normalized coprime factorization and H-infinity loop shaping approach, the H-infinity controller is designed for different flight modes, respectively. Finally, the control law is soft-switched by using the weighted sums of the controlled quantity. The simulation results demonstrate that the presented control system is effective by the robust controller.

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