A nonlinear optimal(H-infinity)control method is developed for a wind power unit that comprises twin turbines,permanent magnet synchronous generators(PMSGs)and AC/DC converters.By proving differential flatness propert...A nonlinear optimal(H-infinity)control method is developed for a wind power unit that comprises twin turbines,permanent magnet synchronous generators(PMSGs)and AC/DC converters.By proving differential flatness properties for this system the associated setpoints definition problem is solved.The dynamic model of the wind power unit being initially expressed in a nonlinear and multivariable state-space form,undergoes approximate linearisation around a temporary operating point that is recomputed at each time-step of the control method.The linearisation relies on first-order Taylor series expansion and on the computation of the associated Jacobian matrices.For the linearised state-space model of the wind power unit,a stabilising optimal(H-infinity)feedback controller is designed.This controller stands for the solution to the nonlinear optimal control problem of the wind power unit under model uncertainty and external perturbations.To compute the controller's feedback gains an algebraic Riccati equation is repetitively solved at each iteration of the control algorithm.The global stability properties of the control method are proven through Lyapunov analysis.Finally,to implement state estimationbased control of the wind power unit,without the need to measure its entire state vector,the H-infinity Kalman Filter is used as a robust state estimator.展开更多
The control problem for the multivariable and nonlinear dynamics of unmanned aerial vehicles and micro-satellites is solved with the use of a flatness-based control approach which is implemented in successive loops.Th...The control problem for the multivariable and nonlinear dynamics of unmanned aerial vehicles and micro-satellites is solved with the use of a flatness-based control approach which is implemented in successive loops.The state-space model of(i)unmanned aerial vehicles and(ii)micro-satellites is separated into two subsystems,which are connected between them in cascading loops.Each one of these subsystems can be viewed independently as a differentially flat system and control about it can be performed with inversion of its dynamics as in the case of input–output linearized flat systems.The state variables of the second subsystem become virtual control inputs for the first subsystem.In turn,exogenous control inputs are applied to the first subsystem.The whole control method is implemented in two successive loops and its global stability properties are also proven through Lyapunov stability analysis.The validity of the control method is confirmed in two case studies:(a)control and trajectories tracking for the autonomous octocopter,(ii)control of the attitude dynamics of micro-satellites.展开更多
The overuse and misuse of antibiotics has become a major problem for public health.People become resistant to antibiotics and because of this the anticipated therapeutic effect is never reached.In-hospital infections ...The overuse and misuse of antibiotics has become a major problem for public health.People become resistant to antibiotics and because of this the anticipated therapeutic effect is never reached.In-hospital infections are often aggravated and large amounts of money are spent for treating complications in the patients'condition.In this paper a nonlinear optimal(H-infinity)control method is developed for the dynamic model of bacterial infections exhibiting resistance to antibiotics.First,differential flatness properties are proven for the associated state-space model.Next,the state-space description undergoes approximate linearization with the use of first-order Taylor series expansion and through the computation of the associated Jacobian matrices.The linearization process takes place at each sampling instance around a time-varying operating point which is defined by the present value of the system's state vector and by the last sampled value of the control inputs vector.For the approximately linearized model of the system a stabilizing H-infinity feedback controller is designed.To compute the controller's gains an algebraic Riccati equation has to be repetitively solved at each time-step of the control algorithm.The global stability properties of the control scheme are proven through Lyapunov analysis.The proposed method achieves stabilization and remedy for the bacterial infection under moderate use of antibiotics.展开更多
文摘A nonlinear optimal(H-infinity)control method is developed for a wind power unit that comprises twin turbines,permanent magnet synchronous generators(PMSGs)and AC/DC converters.By proving differential flatness properties for this system the associated setpoints definition problem is solved.The dynamic model of the wind power unit being initially expressed in a nonlinear and multivariable state-space form,undergoes approximate linearisation around a temporary operating point that is recomputed at each time-step of the control method.The linearisation relies on first-order Taylor series expansion and on the computation of the associated Jacobian matrices.For the linearised state-space model of the wind power unit,a stabilising optimal(H-infinity)feedback controller is designed.This controller stands for the solution to the nonlinear optimal control problem of the wind power unit under model uncertainty and external perturbations.To compute the controller's feedback gains an algebraic Riccati equation is repetitively solved at each iteration of the control algorithm.The global stability properties of the control method are proven through Lyapunov analysis.Finally,to implement state estimationbased control of the wind power unit,without the need to measure its entire state vector,the H-infinity Kalman Filter is used as a robust state estimator.
文摘The control problem for the multivariable and nonlinear dynamics of unmanned aerial vehicles and micro-satellites is solved with the use of a flatness-based control approach which is implemented in successive loops.The state-space model of(i)unmanned aerial vehicles and(ii)micro-satellites is separated into two subsystems,which are connected between them in cascading loops.Each one of these subsystems can be viewed independently as a differentially flat system and control about it can be performed with inversion of its dynamics as in the case of input–output linearized flat systems.The state variables of the second subsystem become virtual control inputs for the first subsystem.In turn,exogenous control inputs are applied to the first subsystem.The whole control method is implemented in two successive loops and its global stability properties are also proven through Lyapunov stability analysis.The validity of the control method is confirmed in two case studies:(a)control and trajectories tracking for the autonomous octocopter,(ii)control of the attitude dynamics of micro-satellites.
基金supported by the Unit of Industrial AutomationIndustrial Systems Institute under Grant No.Ref.301022,Greece and RSP2024R150 of King Saud University,Riyadh,Saudi Arabia。
文摘The overuse and misuse of antibiotics has become a major problem for public health.People become resistant to antibiotics and because of this the anticipated therapeutic effect is never reached.In-hospital infections are often aggravated and large amounts of money are spent for treating complications in the patients'condition.In this paper a nonlinear optimal(H-infinity)control method is developed for the dynamic model of bacterial infections exhibiting resistance to antibiotics.First,differential flatness properties are proven for the associated state-space model.Next,the state-space description undergoes approximate linearization with the use of first-order Taylor series expansion and through the computation of the associated Jacobian matrices.The linearization process takes place at each sampling instance around a time-varying operating point which is defined by the present value of the system's state vector and by the last sampled value of the control inputs vector.For the approximately linearized model of the system a stabilizing H-infinity feedback controller is designed.To compute the controller's gains an algebraic Riccati equation has to be repetitively solved at each time-step of the control algorithm.The global stability properties of the control scheme are proven through Lyapunov analysis.The proposed method achieves stabilization and remedy for the bacterial infection under moderate use of antibiotics.
