In this paper, a neural network based adaptive prescribed performance control scheme is proposed for the altitude and attitude tracking system of the unmanned helicopter in the presence of state and output constraints...In this paper, a neural network based adaptive prescribed performance control scheme is proposed for the altitude and attitude tracking system of the unmanned helicopter in the presence of state and output constraints. For handling the state constraints, the barrier Lyapunov function and the saturation function are employed. And, the prescribed performance method is used to deal with the flapping angle constraints for the unmanned helicopter. It is proved that the proposed control approach can ensure that all the signals of the resulting closed-loop system are bounded, and the tracking errors are within the prescribed performance bounds for all time. The numerical simulation is given to illustrate the performance of the proposed scheme.展开更多
This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance system...This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance systems of missiles is challenging.As our contribution,the velocity control channel is designed to deal with the intractable velocity problem and improve tracking accuracy.The global prescribed performance function,which guarantees the tracking error within the set range and the global convergence of the tracking guidance system,is first proposed based on the traditional PPF.Then,a tracking guidance strategy is derived using the integral sliding mode control techniques to make the sliding manifold and tracking errors converge to zero and avoid singularities.Meanwhile,an improved switching control law is introduced into the designed tracking guidance algorithm to deal with the chattering problem.A back propagation neural network(BPNN)extended state observer(BPNNESO)is employed in the inner loop to identify disturbances.The obtained results indicate that the proposed tracking guidance approach achieves the trajectory tracking guidance objective without and with disturbances and outperforms the existing tracking guidance schemes with the lowest tracking errors,convergence times,and overshoots.展开更多
A prescribed performance adaptive control(PPAC)is proposed for Hammerstein system where nonlinearity is described by backlash-like hysteresis.In order to simplify the controller design as well as guarantee the precisi...A prescribed performance adaptive control(PPAC)is proposed for Hammerstein system where nonlinearity is described by backlash-like hysteresis.In order to simplify the controller design as well as guarantee the precision of the controlled system,the tracking error is transformed into performance error by two steps.The first step is to transform the tracking error into scalar error,but it magnifies the tracking error decreasing the accuracy of the controlled system.Therefore,a new S(z)is proposed for prescribed performance function(PPF)and the second step is transforming the scalar error into performance error by the proposed PPF,which guarantees the scalar error converges to a prescribed bound to improve the control accuracy.Finally,Lambert W function is introduced for the Lyapunov function candidate to guarantee the closed-loop system bounded and the tracking error converged.Simulations demonstrate the effectiveness of the proposed approaches.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 61573184, 61751210)Aeronautical Science Foundation of China (No. 20165752049)the Fundamental Research Funds for the Central Universities of China (No. NE2016101)
文摘In this paper, a neural network based adaptive prescribed performance control scheme is proposed for the altitude and attitude tracking system of the unmanned helicopter in the presence of state and output constraints. For handling the state constraints, the barrier Lyapunov function and the saturation function are employed. And, the prescribed performance method is used to deal with the flapping angle constraints for the unmanned helicopter. It is proved that the proposed control approach can ensure that all the signals of the resulting closed-loop system are bounded, and the tracking errors are within the prescribed performance bounds for all time. The numerical simulation is given to illustrate the performance of the proposed scheme.
基金the National Natural Science Foundation of China(Grant No.12072090).
文摘This paper investigates interception missiles’trajectory tracking guidance problem under wind field and external disturbances in the boost phase.Indeed,the velocity control in such trajectory tracking guidance systems of missiles is challenging.As our contribution,the velocity control channel is designed to deal with the intractable velocity problem and improve tracking accuracy.The global prescribed performance function,which guarantees the tracking error within the set range and the global convergence of the tracking guidance system,is first proposed based on the traditional PPF.Then,a tracking guidance strategy is derived using the integral sliding mode control techniques to make the sliding manifold and tracking errors converge to zero and avoid singularities.Meanwhile,an improved switching control law is introduced into the designed tracking guidance algorithm to deal with the chattering problem.A back propagation neural network(BPNN)extended state observer(BPNNESO)is employed in the inner loop to identify disturbances.The obtained results indicate that the proposed tracking guidance approach achieves the trajectory tracking guidance objective without and with disturbances and outperforms the existing tracking guidance schemes with the lowest tracking errors,convergence times,and overshoots.
基金supported by Shandong Natural Science Foundation of China under Grant No.ZR2017MF048the National Natural Science Foundation of China under Grant No.61433003+3 种基金Shandong Key Research and Development Programme under Grant No.2016GGX105013Shandong Science and Technology Program of Higher Education under Grant No.J17KA214Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents under Grant No.2016RCJJ035Tai’an Science and Technology Development Program under Grant No.2017GX0017
文摘A prescribed performance adaptive control(PPAC)is proposed for Hammerstein system where nonlinearity is described by backlash-like hysteresis.In order to simplify the controller design as well as guarantee the precision of the controlled system,the tracking error is transformed into performance error by two steps.The first step is to transform the tracking error into scalar error,but it magnifies the tracking error decreasing the accuracy of the controlled system.Therefore,a new S(z)is proposed for prescribed performance function(PPF)and the second step is transforming the scalar error into performance error by the proposed PPF,which guarantees the scalar error converges to a prescribed bound to improve the control accuracy.Finally,Lambert W function is introduced for the Lyapunov function candidate to guarantee the closed-loop system bounded and the tracking error converged.Simulations demonstrate the effectiveness of the proposed approaches.
