A nonlinear controller based on an extended second-order disturbance observer is presented to track desired position for an electro-hydraulic single-rod actuator in the presence of both external disturbances and param...A nonlinear controller based on an extended second-order disturbance observer is presented to track desired position for an electro-hydraulic single-rod actuator in the presence of both external disturbances and parameter uncertainties. The proposed extended second-order disturbance observer deals with not only the external perturbations, but also parameter uncertainties which are commonly regarded as lumped disturbances in previous researches. Besides, the outer position tracking loop is designed with cylinder load pressure as output; and the inner pressure control loop provides the hydraulic actuator the characteristic of a force generator. The stability of the closed-loop system is provided based on Lyapunov theory. The performance of the controller is verified through simulations and experiments. The results demonstrate that the proposed nonlinear position tracking controller, together with the extended second-order disturbance observer, gives an excellent tracking performance in the presence of parameter uncertainties and external disturbance.展开更多
A path following controller is proposed to force an underactuated surface ship which is suffering from disturbance to follow a predefined path.The controller is based on analytic model predictive control and unscented...A path following controller is proposed to force an underactuated surface ship which is suffering from disturbance to follow a predefined path.The controller is based on analytic model predictive control and unscented Kalman filter(UKF) techniques.The analytic model predictive control provides a systematic method to get appropriate controller parameters to guarantee the stability of the closed-loop system,and the well-defined relative degree is guaranteed by introducing output-redefinition.The UKF is used to estimate the states and uncertain parameters due to time-varying added mass matrices.With help of the proposed UKF-based controller,the underactuated ship with time-varying parameters can follow a desired straight path.Simulation results are presented to demonstrate the effectiveness of the proposed controller.展开更多
基金Project(51221004)supported by the Science Fund for Creative Research Groups of National Natural Science Foundation of ChinaProject(2012AA041801)supproted by the High-tech Research and Development Program of China
文摘A nonlinear controller based on an extended second-order disturbance observer is presented to track desired position for an electro-hydraulic single-rod actuator in the presence of both external disturbances and parameter uncertainties. The proposed extended second-order disturbance observer deals with not only the external perturbations, but also parameter uncertainties which are commonly regarded as lumped disturbances in previous researches. Besides, the outer position tracking loop is designed with cylinder load pressure as output; and the inner pressure control loop provides the hydraulic actuator the characteristic of a force generator. The stability of the closed-loop system is provided based on Lyapunov theory. The performance of the controller is verified through simulations and experiments. The results demonstrate that the proposed nonlinear position tracking controller, together with the extended second-order disturbance observer, gives an excellent tracking performance in the presence of parameter uncertainties and external disturbance.
基金the National Natural Science Foundation of China (No. 50779033)the National High Technology Research and Development Program (863) of China (No. 2007AA11Z250)
文摘A path following controller is proposed to force an underactuated surface ship which is suffering from disturbance to follow a predefined path.The controller is based on analytic model predictive control and unscented Kalman filter(UKF) techniques.The analytic model predictive control provides a systematic method to get appropriate controller parameters to guarantee the stability of the closed-loop system,and the well-defined relative degree is guaranteed by introducing output-redefinition.The UKF is used to estimate the states and uncertain parameters due to time-varying added mass matrices.With help of the proposed UKF-based controller,the underactuated ship with time-varying parameters can follow a desired straight path.Simulation results are presented to demonstrate the effectiveness of the proposed controller.
