This paper proposes an L_(1)adaptive fault tolerant control method for trajectory tracking of tail-sitter aircraft in the state of motor loss fault.The tail-sitter model considers the uncertainties produced by the fea...This paper proposes an L_(1)adaptive fault tolerant control method for trajectory tracking of tail-sitter aircraft in the state of motor loss fault.The tail-sitter model considers the uncertainties produced by the features of nonlinearities and couplings which cause difficulties in control.An L_(1)adaptive controller is designed to reduce the position and attitude error when actuators have faults.A reference trajectory containing large maneuver flight transitions is designed,which makes it even harder for the L_(1)controller to track accurately.Compensators are designed to assist L_(1)adaptive controller tracking of the reference trajectory.The stability of the L_(1)adaptive controller including compensators is proved.Finally,the simulation results are used to analyse the effectiveness of the proposed controller.Compared to the H∞controller,the L_(1)adaptive controller with compensators has better performance in position control and attitude control under fault tolerance state even when the aircraft conducts large maneuver.Besides,as the L_(1)adaptive control method separates feedback control and adaptive law design,the response speed of the whole system is improved.展开更多
The main advantage of tail-sitter unmanned aerial vehicle (UAV) are introduced. Three design solutions of rotor tail-sitter lift system of UAV have been presented and the respective control strategies and characterist...The main advantage of tail-sitter unmanned aerial vehicle (UAV) are introduced. Three design solutions of rotor tail-sitter lift system of UAV have been presented and the respective control strategies and characteristics of three solutions are also analyzed in the paper, through the related experiments the design of twin-rotor lift system is verified, and its feasibility is proved. The characteristics and the applying background of the twin-rotor tail-sitter UAV are described in detail. Some useful conclusions of the lift system for tail-sitter UAV are obtained.展开更多
As an attractive transition approach,the altitude-hold transition is a special type of super-maneuvering and the vertical/horizontal flight mode transition that an agile aircraft conducts at fixed altitude.However,it ...As an attractive transition approach,the altitude-hold transition is a special type of super-maneuvering and the vertical/horizontal flight mode transition that an agile aircraft conducts at fixed altitude.However,it is still challenging to implement an autonomous control of the altitude-hold transition while the existing optimal transition planning methods cannot avoid an evident altitude change during the transition process.This paper proposes a corridor-based flight mode transition strategy and presents a successful flight demonstration of the altitude-hold transition on a small ducted-fan tail-sitter unmanned aerial vehicle.In the proposed corridor-based methodology,we model and analyze the transition corridor,concentrate on the dynamic characteristics of the altitude-hold transition,and emphasize that a valid transition trajectory should be governed by its transition corridor.The identified transition corridor reveals that for a given velocity trajectory,the solution for the corresponding trajectories of pitch angle and thrust is unique.Based on this,the transition trajectory generation problem is addressed simply on the velocity-acceleration plane.Furthermore,a proper flight control scheme is devised to track the generated transition trajectories.Finally,the effectiveness of the proposed method is verified through practical flight tests,in which the altitude change is less than 1.1 m during the entire transition course.展开更多
The main task of this work is to design a control system for a small tail-sitter Unmanned Aerial Vehicle(UAV)during the transition process.Although reasonable control performance can be obtained through a well-tuned s...The main task of this work is to design a control system for a small tail-sitter Unmanned Aerial Vehicle(UAV)during the transition process.Although reasonable control performance can be obtained through a well-tuned single PID or cascade PID control architecture under nominal conditions,large or fast time-varying disturbances and a wide range of changes in the equilibrium point bring nonlinear characteristics to the transition control during the transition process,which leads to control precision degradation.Meanwhile,the PID controller’s tuning method relies on engineering experiences to a certain extent and the controller parameters need to be retuned under different working conditions,which limits the rapid deployment and preliminary validation.Based on the above issues,a novel control architecture of L1 neural network adaptive control associated with PID control is proposed to improve the compensation ability during the transition process and guarantee the security transition.The L1 neural network adaptive control is revised to solve the multi-input and multi-output problem of the tail-sitter UAV system in this study.Finally,the transition characteristics of the time setting difference between the desired transition speed and the desired transition pitch angle are analyzed.展开更多
Research on the transition phase of tail-sitter Unmanned Aerial Vehicles(UAVs)is crucial for trajectory planning and performance analysis.This study focuses on the analysis of the transition characteristics and path o...Research on the transition phase of tail-sitter Unmanned Aerial Vehicles(UAVs)is crucial for trajectory planning and performance analysis.This study focuses on the analysis of the transition characteristics and path of a small dual-rotor tail-sitter UAV,including static and dynamic computations.The system input time delay and actuator dynamics are specifically considered during the dynamic analysis,and these actual physical properties ensure that the computation results are reliable and reasonable.The UAV steady-state limit is obtained through static analysis,which is also adopted to verify the correctness of the dynamic results.In regard to the dynamic analysis,several typical transition approaches are computed based on different initial states and optimization objective functions,and the different computations are applicable under specific task conditions.The off-line dynamic results of the transition path and actuator output sequence could also be adopted as reference values for the transition process during real flight.A comparison of the static and dynamic results illustrates the necessity of combining these two methods for UAV transition characteristic analysis.Furthermore,the UAV conceptual parameters related to the transition path are also studied,and the obtained quantitative characteristics provide feedback for the UAV conceptual design.展开更多
基金supported by the National Natural Science Foundation of China(61873012)。
文摘This paper proposes an L_(1)adaptive fault tolerant control method for trajectory tracking of tail-sitter aircraft in the state of motor loss fault.The tail-sitter model considers the uncertainties produced by the features of nonlinearities and couplings which cause difficulties in control.An L_(1)adaptive controller is designed to reduce the position and attitude error when actuators have faults.A reference trajectory containing large maneuver flight transitions is designed,which makes it even harder for the L_(1)controller to track accurately.Compensators are designed to assist L_(1)adaptive controller tracking of the reference trajectory.The stability of the L_(1)adaptive controller including compensators is proved.Finally,the simulation results are used to analyse the effectiveness of the proposed controller.Compared to the H∞controller,the L_(1)adaptive controller with compensators has better performance in position control and attitude control under fault tolerance state even when the aircraft conducts large maneuver.Besides,as the L_(1)adaptive control method separates feedback control and adaptive law design,the response speed of the whole system is improved.
文摘The main advantage of tail-sitter unmanned aerial vehicle (UAV) are introduced. Three design solutions of rotor tail-sitter lift system of UAV have been presented and the respective control strategies and characteristics of three solutions are also analyzed in the paper, through the related experiments the design of twin-rotor lift system is verified, and its feasibility is proved. The characteristics and the applying background of the twin-rotor tail-sitter UAV are described in detail. Some useful conclusions of the lift system for tail-sitter UAV are obtained.
基金supported by Scientific Instruments Development Program of National Natural Science Foundation of China(No.61527810)the Fundamental Research Funds for the Central Universities,Chinathe Key Laboratory of Autonomous Systems and Networked Control,Ministry of Education and the Unmanned Aerial Vehicle Systems Engineering Technology Research Center of Guangdong(China)for supporting this research.
文摘As an attractive transition approach,the altitude-hold transition is a special type of super-maneuvering and the vertical/horizontal flight mode transition that an agile aircraft conducts at fixed altitude.However,it is still challenging to implement an autonomous control of the altitude-hold transition while the existing optimal transition planning methods cannot avoid an evident altitude change during the transition process.This paper proposes a corridor-based flight mode transition strategy and presents a successful flight demonstration of the altitude-hold transition on a small ducted-fan tail-sitter unmanned aerial vehicle.In the proposed corridor-based methodology,we model and analyze the transition corridor,concentrate on the dynamic characteristics of the altitude-hold transition,and emphasize that a valid transition trajectory should be governed by its transition corridor.The identified transition corridor reveals that for a given velocity trajectory,the solution for the corresponding trajectories of pitch angle and thrust is unique.Based on this,the transition trajectory generation problem is addressed simply on the velocity-acceleration plane.Furthermore,a proper flight control scheme is devised to track the generated transition trajectories.Finally,the effectiveness of the proposed method is verified through practical flight tests,in which the altitude change is less than 1.1 m during the entire transition course.
基金supported by the Natural Science Basic Research Plan in Shaanxi Province,China(No.2021JQ-214)the Fundamental Research Funds for the Central Universities,China(No.300102251101).
文摘The main task of this work is to design a control system for a small tail-sitter Unmanned Aerial Vehicle(UAV)during the transition process.Although reasonable control performance can be obtained through a well-tuned single PID or cascade PID control architecture under nominal conditions,large or fast time-varying disturbances and a wide range of changes in the equilibrium point bring nonlinear characteristics to the transition control during the transition process,which leads to control precision degradation.Meanwhile,the PID controller’s tuning method relies on engineering experiences to a certain extent and the controller parameters need to be retuned under different working conditions,which limits the rapid deployment and preliminary validation.Based on the above issues,a novel control architecture of L1 neural network adaptive control associated with PID control is proposed to improve the compensation ability during the transition process and guarantee the security transition.The L1 neural network adaptive control is revised to solve the multi-input and multi-output problem of the tail-sitter UAV system in this study.Finally,the transition characteristics of the time setting difference between the desired transition speed and the desired transition pitch angle are analyzed.
基金supported by the Natural Science Basic Research Plan in Shaanxi Province of China(No.:2019JQ411)the Fundamental Research Funds for the Central Universities,China(No.:300102259306)。
文摘Research on the transition phase of tail-sitter Unmanned Aerial Vehicles(UAVs)is crucial for trajectory planning and performance analysis.This study focuses on the analysis of the transition characteristics and path of a small dual-rotor tail-sitter UAV,including static and dynamic computations.The system input time delay and actuator dynamics are specifically considered during the dynamic analysis,and these actual physical properties ensure that the computation results are reliable and reasonable.The UAV steady-state limit is obtained through static analysis,which is also adopted to verify the correctness of the dynamic results.In regard to the dynamic analysis,several typical transition approaches are computed based on different initial states and optimization objective functions,and the different computations are applicable under specific task conditions.The off-line dynamic results of the transition path and actuator output sequence could also be adopted as reference values for the transition process during real flight.A comparison of the static and dynamic results illustrates the necessity of combining these two methods for UAV transition characteristic analysis.Furthermore,the UAV conceptual parameters related to the transition path are also studied,and the obtained quantitative characteristics provide feedback for the UAV conceptual design.
