Designing a controller to stabilize maneuvering hovercrafts is an important challenge in amphibious vehicles.Hovercrafts are implemented in several applications,such as military missions,transportation,and scientific ...Designing a controller to stabilize maneuvering hovercrafts is an important challenge in amphibious vehicles.Hovercrafts are implemented in several applications,such as military missions,transportation,and scientific tasks.Thus.to improve their performance,it is crucial to control the system and compensate uncertainties and disruptions.In this paper,both classic and intelligent approaches are combined to design an observer-based controller.The system is assumed to be both controllable and observable.An adaptive neural network observer with guaranteed stability is derived for the nonlinear dynamics of a hovercraft,which is controlled via a nonsingular super-twisting terminal sliding-mode method.The main merits of the proposed method are as follows:(1) the Lyapunov stability of the overall closed-loop system,(2) the convergence of the tracking and observer errors to zero,(3) the robustness against uncertainties and disturbances,and(4) the reduction of the chattering phenomena.The simulation results validate the excellent performance of the derived method.展开更多
The course-keeping control of underactuated hovercraft with two aft propellers was considered. The control of the heading error and cross-track error was accomplished by the yaw torque merely in this case. The hovercr...The course-keeping control of underactuated hovercraft with two aft propellers was considered. The control of the heading error and cross-track error was accomplished by the yaw torque merely in this case. The hovercraft dynamic model is nonlinear and underactuated. At first the Controllability of course-keeping control for hovercraft was proved, then a course-keeping control law was derived that keeps hovercraft heading constant as well as minimizes the lateral movement of hovercraft. The proposed law guarantees heading error and sway error all converge to zero exponentially. Simulation tests were carried out to illustrate the effectiveness of the proposed control law. For further research, the disturbance influence would be considered in the dynamic equations.展开更多
The efficient and precise application of agricultural materials such as fertilizer or herbicide can be greatly facilitated by autonomous operation.This is especially important under difficult conditions at remote site...The efficient and precise application of agricultural materials such as fertilizer or herbicide can be greatly facilitated by autonomous operation.This is especially important under difficult conditions at remote sites.The purpose of this work is to develop an accurate nonlinear controller using a direct Lyapunov approach to ensure stability of an unmanned hovercraft prototype used for the execution of these agricultural tasks.Such a craft constitutes an underactuated system which has fewer actuators than degrees of freedom.The proposed closed loop system is simulated to demonstrate that a control law can stabilize both the actuated and unactuated degrees of freedom of the hovercraft.It is shown that the position and orientation of the hovercraft achieve high dynamic and steady performance.展开更多
Fractional terminal and super-twisting as two types of fractional sliding mode controller are addressed in the present paper.The proposed methodologies are planned for both the nonlinear fractional-order chaotic syste...Fractional terminal and super-twisting as two types of fractional sliding mode controller are addressed in the present paper.The proposed methodologies are planned for both the nonlinear fractional-order chaotic systems and the nonlinear factional model of Hovercraft.The suggested procedure guarantees the asymptotic stability of fractional-order chaotic systems based on Lyapunov stability theorem,by presenting a set of fractional-order laws.Compared to the previous studies that concentrate on sliding mode controllers with unwanted chattering phenomena,the proposed methodologies deal with chattering reduction of terminal sliding mode controller/super twisting to converge to desired value in finite time,consequently.The main advantages of the offered controllers are 1)closed-loop system stability,2)robustness against external disturbances and uncertainties,3)finite time zero-convergence of the output tracking error,and 4)chattering phenomena reduction.Finally,the simulation results show the performance of the approaches both on the chaotic and Hovercraft models.展开更多
文摘Designing a controller to stabilize maneuvering hovercrafts is an important challenge in amphibious vehicles.Hovercrafts are implemented in several applications,such as military missions,transportation,and scientific tasks.Thus.to improve their performance,it is crucial to control the system and compensate uncertainties and disruptions.In this paper,both classic and intelligent approaches are combined to design an observer-based controller.The system is assumed to be both controllable and observable.An adaptive neural network observer with guaranteed stability is derived for the nonlinear dynamics of a hovercraft,which is controlled via a nonsingular super-twisting terminal sliding-mode method.The main merits of the proposed method are as follows:(1) the Lyapunov stability of the overall closed-loop system,(2) the convergence of the tracking and observer errors to zero,(3) the robustness against uncertainties and disturbances,and(4) the reduction of the chattering phenomena.The simulation results validate the excellent performance of the derived method.
文摘The course-keeping control of underactuated hovercraft with two aft propellers was considered. The control of the heading error and cross-track error was accomplished by the yaw torque merely in this case. The hovercraft dynamic model is nonlinear and underactuated. At first the Controllability of course-keeping control for hovercraft was proved, then a course-keeping control law was derived that keeps hovercraft heading constant as well as minimizes the lateral movement of hovercraft. The proposed law guarantees heading error and sway error all converge to zero exponentially. Simulation tests were carried out to illustrate the effectiveness of the proposed control law. For further research, the disturbance influence would be considered in the dynamic equations.
文摘The efficient and precise application of agricultural materials such as fertilizer or herbicide can be greatly facilitated by autonomous operation.This is especially important under difficult conditions at remote sites.The purpose of this work is to develop an accurate nonlinear controller using a direct Lyapunov approach to ensure stability of an unmanned hovercraft prototype used for the execution of these agricultural tasks.Such a craft constitutes an underactuated system which has fewer actuators than degrees of freedom.The proposed closed loop system is simulated to demonstrate that a control law can stabilize both the actuated and unactuated degrees of freedom of the hovercraft.It is shown that the position and orientation of the hovercraft achieve high dynamic and steady performance.
文摘Fractional terminal and super-twisting as two types of fractional sliding mode controller are addressed in the present paper.The proposed methodologies are planned for both the nonlinear fractional-order chaotic systems and the nonlinear factional model of Hovercraft.The suggested procedure guarantees the asymptotic stability of fractional-order chaotic systems based on Lyapunov stability theorem,by presenting a set of fractional-order laws.Compared to the previous studies that concentrate on sliding mode controllers with unwanted chattering phenomena,the proposed methodologies deal with chattering reduction of terminal sliding mode controller/super twisting to converge to desired value in finite time,consequently.The main advantages of the offered controllers are 1)closed-loop system stability,2)robustness against external disturbances and uncertainties,3)finite time zero-convergence of the output tracking error,and 4)chattering phenomena reduction.Finally,the simulation results show the performance of the approaches both on the chaotic and Hovercraft models.
