In this paper, a disturbance observer-based safe tracking control scheme is proposed for a medium-scale unmanned helicopter with rotor flapping dynamics in the presence of partial state constraints and unknown externa...In this paper, a disturbance observer-based safe tracking control scheme is proposed for a medium-scale unmanned helicopter with rotor flapping dynamics in the presence of partial state constraints and unknown external disturbances. A safety protection algorithm is proposed to keep the constrained states within the given safe-set. A second-order disturbance observer technique is utilized to estimate the external disturbances. It is shown that the desired tracking performance of the controlled unmanned helicopter can be achieved with the application of the backstepping approach, dynamic surface control technique, and Lyapunov method. Finally, the availability of the proposed control scheme has been shown by simulation results.展开更多
Adaptive flight control technology, feedback linearization, model inversion theory are reviewed and the error dynamic characteristics are analyzed, and an adaptive on-line neural network attitude control system is pre...Adaptive flight control technology, feedback linearization, model inversion theory are reviewed and the error dynamic characteristics are analyzed, and an adaptive on-line neural network attitude control system is presented. The model inversion is under the hover condition. And the adaptive control law based on the neural network is designed to guarantee the boundedness of tracking error and control signals. Simulation results demonstrate that the nonlinear neural network augmented model inversion can self-adapt to the uncertainty and modeling errors of unmanned helicopters. Results are compared while the parameters of PD controller and robustness items are changed.展开更多
A robust anti-swing control method based on the error transformation function is proposed,and the problem is handled for the unmanned helicopter slung-load system(HSLS)deviating from the equilibrium state due to the d...A robust anti-swing control method based on the error transformation function is proposed,and the problem is handled for the unmanned helicopter slung-load system(HSLS)deviating from the equilibrium state due to the disturbances in the lifting process.First,the nonlinear model of unmanned HSLS is established.Second,the errors of swing angles are constructed by using the two ideal swing angle values and the actual swing angle values for the unmanned HSLS under flat flight,and the error transformation functions are investigated to guarantee that the errors of swing angles satisfy the prescribed performance.Third,the nonlinear disturbance observers are introduced to estimate the bounded disturbances,and the robust controllers of the unmanned HSLS,the velocity and the attitude subsystems are designed based on the prescribed performance method,the output of disturbance observer and the sliding mode backstepping strategy,respectively.Fourth,the Lyapunov function is developed to prove the stability of the closed-loop system.Finally,the simulation studies are shown to demonstrate the effectiveness of the control strategy.展开更多
Due to potential wide applications,the problem of utilizing an unmanned helicopter to track a ground target has become one of the most active research directions in related areas.However,in most cases,it is possible f...Due to potential wide applications,the problem of utilizing an unmanned helicopter to track a ground target has become one of the most active research directions in related areas.However,in most cases,it is possible for a dynamic target to implement evasive actions with strong maneuverability,such as a sudden turn during high-speed movement,to flee from the tracker,which then brings much difficulty for the design of tracking control systems.Currently,most research on this field focuses on utilizing a ground mobile robot to track a high-speed target.Unfortunately,it is very difficult to extend those developed methods to airborne applications due to much more complex dynamices of UAV-target relative motion.This study investiages thoroughly for the problem of using an unmanned helicopter to track a ground target,with particular emphasis on the avoidance of tracking failure caused by the evasive maneuvers of dynamic targets.Specifically,a novel control scheme,which consists of an innovative target tracking controller and a classical flight controller,is proposed for the helicopter-target tracking problem.Wherein,the tracking controller,whose design is the focus of the paper,aims to utilize the motion information of the helicopter and the dynamic target to construct a suitable trajectory for the helicopter,so that when it flies along this trajectory,the relative pose between the helicopter and the dynamic target will be kept consant.When designing the target tracking controller,a novel coordinate transformation is firstly introduced to convert the tracking system into a more compact form convenient for control law design,the desired velocities for the helicopter is then proposed with consideration of the dynamic constraint.The stability of the closed-loop system is finally analyzed by Lyapunov techniques.Based on Matlab/Simulink environment,two groups of simulation are conducted for the helicopter-target tracking control system where the target moves along a linear path and takes a sudden turn during high-speed movement,respectively.As shown by the simulation results,both the distance error and the pointing error are bounded during the tracking process,and they are convergent to zero when the target moves straightly.Moreover,the tracking performance can be adjusted properly to avoid tracking failure due to evasive maneuvers of the target,so as to guarantee superior tracking performance for all kinds of dynamic targets.展开更多
Quadrotor unmanned helicopter is a new popular research platform for unmanned aerial vehicle(UAV),thanks to its simple construction,vertical take-off and landing(VTOL)capability.Here a nonlinear intelligent flight con...Quadrotor unmanned helicopter is a new popular research platform for unmanned aerial vehicle(UAV),thanks to its simple construction,vertical take-off and landing(VTOL)capability.Here a nonlinear intelligent flight control system is developed for quadrotor unmanned helicopter,including trajectory control loop composed of co-controller and state estimator,and attitude control loop composed of brain emotional learning(BEL)intelligent controller.BEL intelligent controller based on mammalian middle brain is characterized as self-learning capability,model-free and robustness.Simulation results of a small quadrotor unmanned helicopter show that the BEL intelligent controller-based flight control system has faster dynamical responses with higher precision than the traditional controller-based system.展开更多
It is devoted to the development of an autonomous flight control system for small size unmanned helicopter based on dynamical model. At first, the mathematical model of a small size helicopter is described. After that...It is devoted to the development of an autonomous flight control system for small size unmanned helicopter based on dynamical model. At first, the mathematical model of a small size helicopter is described. After that simple but effective MTCV control algorithm was proposed. The whole flight control algorithm is composed of two parts: orientation controller based on the model for rotation dynamics and a robust position controller for a double integrator. The MTCV block is also used to achieve translation velocity control. To demonstrate the performance of the presented algorithm, simulation results and results achieved in real flight experiments were presented.展开更多
A new landing region selection algorithm for an unmanned helicopter is proposed based on an attention model.Different from the original attention model,some properties of the possible safe landing regions（e.g.,depth,...A new landing region selection algorithm for an unmanned helicopter is proposed based on an attention model.Different from the original attention model,some properties of the possible safe landing regions（e.g.,depth,regional color and motion features）are included in the selection algorithm.Furthermore,regional color and motion features are fused directly into the saliency map because these features do not have the ＂central-peripheral＂property.Experimental results validate the feasibility and efficiency of this approach.展开更多
Attitude identification method for unmanned helicopter based on fuzzy model at hovering is presented. The dynamical attitude model is considered as basis for attitude control and it is very complex. To reduce the comp...Attitude identification method for unmanned helicopter based on fuzzy model at hovering is presented. The dynamical attitude model is considered as basis for attitude control and it is very complex. To reduce the complexity of model, nonlinear model of unmanned helicopter with unknown parameters are to be determined by fuzzy system first and then derivative based gradient method is used to identify unknown parameters of model. Gradient method is used due to ability that fuzzy system is not necessarily to be linear in parameters, therefore all fuzzy sets for input and output can be adjusted. The validity of the proposed model was verified using experimental data obtained by the commercially available flight simulator X-Plane. The simulation results showed high accuracy of the modeling method and attitude dynamics data matched well with experimental data.展开更多
Spinsonde is a chute-free vertical retardation technique specifically developed for fixed-wing unmanned aircraft to acquire accurate measurement of vertical wind speed profile for meteorological applications. Key adva...Spinsonde is a chute-free vertical retardation technique specifically developed for fixed-wing unmanned aircraft to acquire accurate measurement of vertical wind speed profile for meteorological applications. Key advantages of spinsonde over the expendable chute-operated dropsondes are the ability to acquire multi-cycle measurement, efficient use of payload capacity and cost-effectiveness. This work proposes the concept of “rotosonde”, which is the spinsonde equivalent for unmanned helicopters. Computer simulations are carried out to evaluate the performance of the rotosonde and results indicate that the measured speed generally correlates with the wind speed to within ±3 km·h﹣1 even for intensities in excess of 180 km·h﹣1. The profound implication of this work is that unmanned helicopters can now be considered for important field of studies such as cyclogenesis given their reliability to operate in gusty wind conditions in remote oceans, particularly during docking and launching from carriers.展开更多
Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging terrains.This study presents a novel cable-driven legged landing gear(CLG)with...Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging terrains.This study presents a novel cable-driven legged landing gear(CLG)with differential transmission for unmanned helicopters in complex landing environments.To obtain the preferred configuration of the legged mechanism,a multi-objective optimization framework for the CLG is constructed by concurrently considering terrain adaptability,landing stability and reasonable linkage of internal forces.The non-dominated sorting genetic algorithmⅡis employed to numerically acquire the optimal scale parameters that guide the mechanical design of the CLG.An unmanned helicopter prototype equipped with the devised CLG is developed with key performance assessment.Experimental results show that the devised CLG can provide energy-efficient support over uneven terrains(totally driven torque demand less than 0.1 N m)in quasi-static landing tests,and favorable terrain adaptability(posture fluctuation of the fuselage less than±1°)in unknown slope landing tests.These exhibited merits give the proposed CLG the potential to enhance the landing performance of future aircraft in extreme environments.展开更多
This work studies the trajectory tracking control for unmanned aerial helicopter(UAH)system under both matched disturbance and mismatched ones.Initially,to tackle the strong coupling,an input-output feedback lineariza...This work studies the trajectory tracking control for unmanned aerial helicopter(UAH)system under both matched disturbance and mismatched ones.Initially,to tackle the strong coupling,an input-output feedback linearization method is utilized to simplify the nonlinear UAH system.Secondly,a set of finite-time disturbance observers(FTDOs)are proposed to estimate mismatched disturbances with their successive derivatives,which are utilized to design the feedforward controller via backstepping.Thirdly,as for matched disturbance,by defining the disturbance characterization index(DCI)to determine whether the disturbance is harmful or not for the UAH system,a feedback controller is proposed and a sufficient condition is established to ensure the convergence of the tracking error.Finally,some numerical simulations and comparisons illustrate the validity and advantages of our control scheme.展开更多
基金supported in part by the National Natural ScienceFoundation of China (U2013201)the National Science Fund for Distinguished Young Scholars (61825302)the Postgraduate Research&Practice Innovation Program of Jiangsu Province (KYCX20_0208)。
文摘In this paper, a disturbance observer-based safe tracking control scheme is proposed for a medium-scale unmanned helicopter with rotor flapping dynamics in the presence of partial state constraints and unknown external disturbances. A safety protection algorithm is proposed to keep the constrained states within the given safe-set. A second-order disturbance observer technique is utilized to estimate the external disturbances. It is shown that the desired tracking performance of the controlled unmanned helicopter can be achieved with the application of the backstepping approach, dynamic surface control technique, and Lyapunov method. Finally, the availability of the proposed control scheme has been shown by simulation results.
文摘Adaptive flight control technology, feedback linearization, model inversion theory are reviewed and the error dynamic characteristics are analyzed, and an adaptive on-line neural network attitude control system is presented. The model inversion is under the hover condition. And the adaptive control law based on the neural network is designed to guarantee the boundedness of tracking error and control signals. Simulation results demonstrate that the nonlinear neural network augmented model inversion can self-adapt to the uncertainty and modeling errors of unmanned helicopters. Results are compared while the parameters of PD controller and robustness items are changed.
基金This work was supported in part by the National Natural Science Foundation of China(No.62003163)the National Science Fund for the Key R&D projects(Social Development)in Jiangsu Province of China(No.BE2020704)+3 种基金the Aeronautical Science Foundation of China(Nos.201957052001,20200007052001)the Jiangsu Province“333”project(No.BRA2019051)the Postdoctoral Research Foundation of Jiangsu Province(No.2020Z112)the Natural Science Foundation of Jiangsu Province for Young Scholars(No.BK20200415)。
文摘A robust anti-swing control method based on the error transformation function is proposed,and the problem is handled for the unmanned helicopter slung-load system(HSLS)deviating from the equilibrium state due to the disturbances in the lifting process.First,the nonlinear model of unmanned HSLS is established.Second,the errors of swing angles are constructed by using the two ideal swing angle values and the actual swing angle values for the unmanned HSLS under flat flight,and the error transformation functions are investigated to guarantee that the errors of swing angles satisfy the prescribed performance.Third,the nonlinear disturbance observers are introduced to estimate the bounded disturbances,and the robust controllers of the unmanned HSLS,the velocity and the attitude subsystems are designed based on the prescribed performance method,the output of disturbance observer and the sliding mode backstepping strategy,respectively.Fourth,the Lyapunov function is developed to prove the stability of the closed-loop system.Finally,the simulation studies are shown to demonstrate the effectiveness of the control strategy.
基金supported by National Natural Science Foundation of China (Grant No. 60875055)Opening Project of State Key Laboratory of Robotics,China (Grant No. RLO200814)
文摘Due to potential wide applications,the problem of utilizing an unmanned helicopter to track a ground target has become one of the most active research directions in related areas.However,in most cases,it is possible for a dynamic target to implement evasive actions with strong maneuverability,such as a sudden turn during high-speed movement,to flee from the tracker,which then brings much difficulty for the design of tracking control systems.Currently,most research on this field focuses on utilizing a ground mobile robot to track a high-speed target.Unfortunately,it is very difficult to extend those developed methods to airborne applications due to much more complex dynamices of UAV-target relative motion.This study investiages thoroughly for the problem of using an unmanned helicopter to track a ground target,with particular emphasis on the avoidance of tracking failure caused by the evasive maneuvers of dynamic targets.Specifically,a novel control scheme,which consists of an innovative target tracking controller and a classical flight controller,is proposed for the helicopter-target tracking problem.Wherein,the tracking controller,whose design is the focus of the paper,aims to utilize the motion information of the helicopter and the dynamic target to construct a suitable trajectory for the helicopter,so that when it flies along this trajectory,the relative pose between the helicopter and the dynamic target will be kept consant.When designing the target tracking controller,a novel coordinate transformation is firstly introduced to convert the tracking system into a more compact form convenient for control law design,the desired velocities for the helicopter is then proposed with consideration of the dynamic constraint.The stability of the closed-loop system is finally analyzed by Lyapunov techniques.Based on Matlab/Simulink environment,two groups of simulation are conducted for the helicopter-target tracking control system where the target moves along a linear path and takes a sudden turn during high-speed movement,respectively.As shown by the simulation results,both the distance error and the pointing error are bounded during the tracking process,and they are convergent to zero when the target moves straightly.Moreover,the tracking performance can be adjusted properly to avoid tracking failure due to evasive maneuvers of the target,so as to guarantee superior tracking performance for all kinds of dynamic targets.
基金supported in part by the National Natural Science Foundation of China(No.61304223)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20123218120015)+1 种基金the Fundamental Research Funds for the Central Universities(No.NZ2015206)the Aeronautical Science Foundation of China(No.2010ZA52002)
文摘Quadrotor unmanned helicopter is a new popular research platform for unmanned aerial vehicle(UAV),thanks to its simple construction,vertical take-off and landing(VTOL)capability.Here a nonlinear intelligent flight control system is developed for quadrotor unmanned helicopter,including trajectory control loop composed of co-controller and state estimator,and attitude control loop composed of brain emotional learning(BEL)intelligent controller.BEL intelligent controller based on mammalian middle brain is characterized as self-learning capability,model-free and robustness.Simulation results of a small quadrotor unmanned helicopter show that the BEL intelligent controller-based flight control system has faster dynamical responses with higher precision than the traditional controller-based system.
基金The National Natural Science Foundation of China(No60475039)
文摘It is devoted to the development of an autonomous flight control system for small size unmanned helicopter based on dynamical model. At first, the mathematical model of a small size helicopter is described. After that simple but effective MTCV control algorithm was proposed. The whole flight control algorithm is composed of two parts: orientation controller based on the model for rotation dynamics and a robust position controller for a double integrator. The MTCV block is also used to achieve translation velocity control. To demonstrate the performance of the presented algorithm, simulation results and results achieved in real flight experiments were presented.
基金Supported by Aeronautical Science Foundation of China(20130542025)
文摘A new landing region selection algorithm for an unmanned helicopter is proposed based on an attention model.Different from the original attention model,some properties of the possible safe landing regions（e.g.,depth,regional color and motion features）are included in the selection algorithm.Furthermore,regional color and motion features are fused directly into the saliency map because these features do not have the ＂central-peripheral＂property.Experimental results validate the feasibility and efficiency of this approach.
文摘Attitude identification method for unmanned helicopter based on fuzzy model at hovering is presented. The dynamical attitude model is considered as basis for attitude control and it is very complex. To reduce the complexity of model, nonlinear model of unmanned helicopter with unknown parameters are to be determined by fuzzy system first and then derivative based gradient method is used to identify unknown parameters of model. Gradient method is used due to ability that fuzzy system is not necessarily to be linear in parameters, therefore all fuzzy sets for input and output can be adjusted. The validity of the proposed model was verified using experimental data obtained by the commercially available flight simulator X-Plane. The simulation results showed high accuracy of the modeling method and attitude dynamics data matched well with experimental data.
文摘Spinsonde is a chute-free vertical retardation technique specifically developed for fixed-wing unmanned aircraft to acquire accurate measurement of vertical wind speed profile for meteorological applications. Key advantages of spinsonde over the expendable chute-operated dropsondes are the ability to acquire multi-cycle measurement, efficient use of payload capacity and cost-effectiveness. This work proposes the concept of “rotosonde”, which is the spinsonde equivalent for unmanned helicopters. Computer simulations are carried out to evaluate the performance of the rotosonde and results indicate that the measured speed generally correlates with the wind speed to within ±3 km·h﹣1 even for intensities in excess of 180 km·h﹣1. The profound implication of this work is that unmanned helicopters can now be considered for important field of studies such as cyclogenesis given their reliability to operate in gusty wind conditions in remote oceans, particularly during docking and launching from carriers.
基金supported by the National Natural Science Foundation of China(Grant No.52175011)。
文摘Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging terrains.This study presents a novel cable-driven legged landing gear(CLG)with differential transmission for unmanned helicopters in complex landing environments.To obtain the preferred configuration of the legged mechanism,a multi-objective optimization framework for the CLG is constructed by concurrently considering terrain adaptability,landing stability and reasonable linkage of internal forces.The non-dominated sorting genetic algorithmⅡis employed to numerically acquire the optimal scale parameters that guide the mechanical design of the CLG.An unmanned helicopter prototype equipped with the devised CLG is developed with key performance assessment.Experimental results show that the devised CLG can provide energy-efficient support over uneven terrains(totally driven torque demand less than 0.1 N m)in quasi-static landing tests,and favorable terrain adaptability(posture fluctuation of the fuselage less than±1°)in unknown slope landing tests.These exhibited merits give the proposed CLG the potential to enhance the landing performance of future aircraft in extreme environments.
基金This work was supported by National Natural Science Foundations of China(Nos.62073164,61873127,61922042)the Foundation of Equipment Pre-research Project of Key Laboratory(No.61422200306).
文摘This work studies the trajectory tracking control for unmanned aerial helicopter(UAH)system under both matched disturbance and mismatched ones.Initially,to tackle the strong coupling,an input-output feedback linearization method is utilized to simplify the nonlinear UAH system.Secondly,a set of finite-time disturbance observers(FTDOs)are proposed to estimate mismatched disturbances with their successive derivatives,which are utilized to design the feedforward controller via backstepping.Thirdly,as for matched disturbance,by defining the disturbance characterization index(DCI)to determine whether the disturbance is harmful or not for the UAH system,a feedback controller is proposed and a sufficient condition is established to ensure the convergence of the tracking error.Finally,some numerical simulations and comparisons illustrate the validity and advantages of our control scheme.
