Designing a controller for the docking maneuver in Probe-Drogue Refueling(PDR) is an important but challenging task, due to the complex system model and the high precision requirement.In order to overcome the disadvan...Designing a controller for the docking maneuver in Probe-Drogue Refueling(PDR) is an important but challenging task, due to the complex system model and the high precision requirement.In order to overcome the disadvantage of only feedback control, a feedforward control scheme known as Iterative Learning Control(ILC) is adopted in this paper.First, Additive State Decomposition(ASD) is used to address the tight coupling of input saturation, nonlinearity and the property of Non Minimum Phase(NMP) by separating these features into two subsystems(a primary system and a secondary system).After system decomposition, an adjoint-type ILC is applied to the Linear Time-Invariant(LTI) primary system with NMP to achieve entire output trajectory tracking, whereas state feedback is used to stabilize the secondary system with input saturation.The two controllers designed for the two subsystems can be combined to achieve the original control goal of the PDR system.Furthermore, to compensate for the receiverindependent uncertainties, a correction action is proposed by using the terminal docking error,which can lead to a smaller docking error at the docking moment.Simulation tests have been carried out to demonstrate the performance of the proposed control method, which has some advantages over the traditional derivative-type ILC and adjoint-type ILC in the docking control of PDR.展开更多
针对重复运行的未知非最小相位系统的轨迹跟踪问题,结合时域稳定逆特点,提出了一种新的基函数型自适应迭代学习控制(Basis function based adaptive iterative learning control,BFAILC)算法.该算法在迭代控制过程中应用自适应迭代学习...针对重复运行的未知非最小相位系统的轨迹跟踪问题,结合时域稳定逆特点,提出了一种新的基函数型自适应迭代学习控制(Basis function based adaptive iterative learning control,BFAILC)算法.该算法在迭代控制过程中应用自适应迭代学习辨识算法估计基函数模型,采用伪逆型学习律逼近系统的稳定逆,保证了迭代学习控制的收敛性和鲁棒性.以傅里叶基函数为例,通过在非最小相位系统上的控制仿真,验证了算法的有效性.展开更多
Underwater gliders are highly efficient,buoyancy-driven,and winged autonomous underwater vehicles.Their dynamics are multivariable nonlinear systems with unstable internal dynamics and thus their motion control is a s...Underwater gliders are highly efficient,buoyancy-driven,and winged autonomous underwater vehicles.Their dynamics are multivariable nonlinear systems with unstable internal dynamics and thus their motion control is a significant challenge.To improve the inherent efficiency and enhance the behavior of the underwater glider over a wide operating regime,a nonlinear feedforward and feedback controller was developed.The nonlinear feedforward control design is based on a new stable inversion technique which determines a causal and bounded solution for the unstable internal dynamics.The feedback control law was designed by a quadratic optimal control method.Simulation results show that the derived control system is able to deal with nonminimum phase system and successfully achieves the tracking of planned output trajectories from initial to final conditions.Furthermore,the control effort is very low,which means the glider with limited power storage has longer range and higher endurance.展开更多
The ill-conditioned stable inversion is studied for slightly nonminimum phase systems whose zero dynam- ics is singularly perturbed, that is, the relative degree is ill-defined. For these systems, we show that there e...The ill-conditioned stable inversion is studied for slightly nonminimum phase systems whose zero dynam- ics is singularly perturbed, that is, the relative degree is ill-defined. For these systems, we show that there exists an inherent limitation in the bandwidth of a reference trajectory to be tracked when a well-conditioned feedforward input via stable inversion is sought. We assert that, when the violation of this limitation occurs, the so-called reference trajectory redesign is called for. Our analysis results can provide an explicit assessment as well as useful guidance for the reference trajectory redesign if needed.展开更多
Use stable inversion to accomplish precise decoupling tracking of airspeed and altitude for conventional takeoff and landing of unmanned aerial vehicles (UAVs) is in essence a non-minimum phase output tracking problem...Use stable inversion to accomplish precise decoupling tracking of airspeed and altitude for conventional takeoff and landing of unmanned aerial vehicles (UAVs) is in essence a non-minimum phase output tracking problem. The main contribution of this article is that a new method to calculate the causal solution of stable inversion is proposed by introducing a well defined perturbed signal to the system’s unstable internal dynamics. It is helpful to overcome the pitfalls resulting from non-causality in existin...展开更多
基金supported by the National Natural Science Foundation of China(No.61473012)。
文摘Designing a controller for the docking maneuver in Probe-Drogue Refueling(PDR) is an important but challenging task, due to the complex system model and the high precision requirement.In order to overcome the disadvantage of only feedback control, a feedforward control scheme known as Iterative Learning Control(ILC) is adopted in this paper.First, Additive State Decomposition(ASD) is used to address the tight coupling of input saturation, nonlinearity and the property of Non Minimum Phase(NMP) by separating these features into two subsystems(a primary system and a secondary system).After system decomposition, an adjoint-type ILC is applied to the Linear Time-Invariant(LTI) primary system with NMP to achieve entire output trajectory tracking, whereas state feedback is used to stabilize the secondary system with input saturation.The two controllers designed for the two subsystems can be combined to achieve the original control goal of the PDR system.Furthermore, to compensate for the receiverindependent uncertainties, a correction action is proposed by using the terminal docking error,which can lead to a smaller docking error at the docking moment.Simulation tests have been carried out to demonstrate the performance of the proposed control method, which has some advantages over the traditional derivative-type ILC and adjoint-type ILC in the docking control of PDR.
文摘针对重复运行的未知非最小相位系统的轨迹跟踪问题,结合时域稳定逆特点,提出了一种新的基函数型自适应迭代学习控制(Basis function based adaptive iterative learning control,BFAILC)算法.该算法在迭代控制过程中应用自适应迭代学习辨识算法估计基函数模型,采用伪逆型学习律逼近系统的稳定逆,保证了迭代学习控制的收敛性和鲁棒性.以傅里叶基函数为例,通过在非最小相位系统上的控制仿真,验证了算法的有效性.
基金the National Natural Science Foundation of China(No. 50979058)the Special Research Fund for the Doctoral Program of Higher Education(No. 20090073110012)
文摘Underwater gliders are highly efficient,buoyancy-driven,and winged autonomous underwater vehicles.Their dynamics are multivariable nonlinear systems with unstable internal dynamics and thus their motion control is a significant challenge.To improve the inherent efficiency and enhance the behavior of the underwater glider over a wide operating regime,a nonlinear feedforward and feedback controller was developed.The nonlinear feedforward control design is based on a new stable inversion technique which determines a causal and bounded solution for the unstable internal dynamics.The feedback control law was designed by a quadratic optimal control method.Simulation results show that the derived control system is able to deal with nonminimum phase system and successfully achieves the tracking of planned output trajectories from initial to final conditions.Furthermore,the control effort is very low,which means the glider with limited power storage has longer range and higher endurance.
基金the National Natural Science Foundation of China (No.60473120)the Natural Science Foundation of Guangdong(No.6023190)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry of China.
文摘The ill-conditioned stable inversion is studied for slightly nonminimum phase systems whose zero dynam- ics is singularly perturbed, that is, the relative degree is ill-defined. For these systems, we show that there exists an inherent limitation in the bandwidth of a reference trajectory to be tracked when a well-conditioned feedforward input via stable inversion is sought. We assert that, when the violation of this limitation occurs, the so-called reference trajectory redesign is called for. Our analysis results can provide an explicit assessment as well as useful guidance for the reference trajectory redesign if needed.
基金Weapons Equipment Pre-research Foundation of China (9140 A25040106HK0118)
文摘Use stable inversion to accomplish precise decoupling tracking of airspeed and altitude for conventional takeoff and landing of unmanned aerial vehicles (UAVs) is in essence a non-minimum phase output tracking problem. The main contribution of this article is that a new method to calculate the causal solution of stable inversion is proposed by introducing a well defined perturbed signal to the system’s unstable internal dynamics. It is helpful to overcome the pitfalls resulting from non-causality in existin...
