scholarly journals Neural Networks Approximator Based Robust Adaptive Controller Design of Hypersonic Flight Vehicles Systems Coupled with Stochastic Disturbance and Dynamic Uncertainties

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Guoqiang Zhu ◽  
Lingfang Sun ◽  
Xiuyu Zhang
Keyword(s):  
Controller Design ◽  
Tracking Error ◽  
Adaptive Controller ◽  
Stochastic Disturbance ◽  
Hypersonic Flight ◽  
Flight Vehicles ◽  
Uncertain Dynamics ◽  
Robust Adaptive ◽  
And Performance ◽  
Dynamic Uncertainties

A neural network robust control is proposed for a class of generic hypersonic flight vehicles with uncertain dynamics and stochastic disturbance. Compared with the present schemes of dealing with dynamic uncertainties and stochastic disturbance, the outstanding feature of the proposed scheme is that only one parameter needs to be estimated at each design step, so that the computational burden can be greatly reduced and the designed controller is much simpler. Moreover, by introducing a performance function in controller design, the prespecified transient and performance of tracking error can be guaranteed. It is proved that all signals of closed-loop system are uniformly ultimately bounded. The simulation results are carried out to illustrate effectiveness of the proposed control algorithm.

A Non-Conservative Approach for the Estimation of the Region of Operation of Uncertain Adaptive Control Systems

2015 ◽  
Author(s):  
Mario Luca Fravolini ◽  
Tansel Yucelen ◽  
Antonio Moschitta ◽  
Benjamin Gruenwald
Keyword(s):  
Adaptive Control ◽  
Control Systems ◽  
Lyapunov Functions ◽  
Controller Design ◽  
Tracking Error ◽  
Adaptive Controller ◽  
Adaptive Control Systems ◽  
Short Period ◽  
Conservative Estimation ◽  
And Performance

A challenging problem for Model Reference Adaptive Control Systems is the accurate characterization of the transient response in the presence of large uncertainties. Early prior research by the authors has demonstrated that using a projection mechanism for parameters adaptation the tracking error dynamics behaves as a linear system perturbed by bounded uncertainties. This brings the benefit that the stability analysis can be cast in terms of a convex optimization problem with LMI constraints so that efficient numerical tools can be used for the adaptive controller design. A possible limitation of the approach is that the design is restricted to quadratic control Lyapunov functions that could produce a conservative estimation of the regions of operation for the actual uncertain adaptive system. In this paper this approach is extended to arbitrary high degree polynomial Lyapunov functions by translating the design and performance requirements in terms of Sum of Square (SOS) inequalities and then using SOS optimization tools for the design. In this effort the new SOS approach is introduced and compared with the previous one. A numerical example based on the short period longitudinal dynamics of the F16 aircraft is used to demonstrate the efficacy of the novel method.

Bilateral Adaptive Control of Nonlinear Teleoperation Systems With Uncertain Dynamics and Dead-Zone

2018 ◽  
Vol 140 (12) ◽  
Author(s):  
Xia Liu ◽  
Mahdi Tavakoli
Keyword(s):  
Adaptive Control ◽  
Function Analysis ◽  
Dead Zone ◽  
Adaptive Controller ◽  
Bilateral Control ◽  
Uncertain Dynamics ◽  
Teleoperation System ◽  
Control Scheme ◽  
Teleoperation Systems ◽  
Dynamic Uncertainties

Dead-zone is one of the most common hard nonlinearities ubiquitous in master–slave teleoperation systems, particularly in the slave robot joints. However, adaptive control techniques applied in teleoperation systems usually deal with dynamic uncertainty but ignore the presence of dead-zone. Dead-zone has the potential to remarkably deteriorate the transparency of a teleoperation system in the sense of position and force tracking performance or even destabilizing the system if not compensated for in the control scheme. In this paper, an adaptive bilateral control scheme is proposed for nonlinear teleoperation systems in the presence of both uncertain dynamics and dead-zone. An adaptive controller is designed for the master robot with dynamic uncertainties and the other is developed for the slave robot with both dynamic uncertainties and unknown dead-zone. The two controllers are incorporated into the four-channel bilateral teleoperation control framework to achieve transparency. The transparency and stability of the closed-loop teleoperation system is studied via a Lyapunov function analysis. Comparisons with the conventional adaptive control which merely deal with dynamic uncertainties in the simulations demonstrate the validity of the proposed approach.

scholarly journals Prescribed Performance Tracking Control for Hypersonic Flight Vehicles with Model Uncertainties

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Siyuan Zhao ◽  
Xiaobing Li ◽  
Xiangwei Bu ◽  
Dongyang Zhang
Keyword(s):  
Tracking Control ◽  
Tracking Error ◽  
Longitudinal Motion ◽  
Model Uncertainties ◽  
Prescribed Performance ◽  
Hypersonic Flight ◽  
Flight Vehicles ◽  
Performance Tracking ◽  
Control Objective ◽  
Proportional Integral Controller

This paper proposes a novel prescribed performance tracking control for a hypersonic flight vehicle (HFV) with model uncertainties. Firstly, a HFV longitudinal motion model is decomposed into a velocity subsystem and an altitude subsystem. Meanwhile, considering the uncertainties of the model, the velocity subsystem and altitude subsystem are directly expressed as the forms with unknown nonaffine functions. Secondly, a novel performance function without initial error is proposed for limiting the tracking error into a prescribed range. Then, for the altitude subsystem, the control objective is changed by model transformation and the prescribed performance backstepping controller is designed. For the velocity subsystem, a prescribed performance proportional-integral controller is proposed which has better engineering practicability. The designed controller is not only simple in form but also has few calculating parameters. Finally, the simulation results show that the proposed controller has good practicability.

scholarly journals Direct Adaptive Tracking Control for a Class of Pure-Feedback Stochastic Nonlinear Systems Based on Fuzzy-Approximation

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Huanqing Wang ◽  
Xiaoping Liu ◽  
Qi Zhou ◽  
Hamid Reza Karimi
Keyword(s):  
Nonlinear Systems ◽  
Tracking Control ◽  
Controller Design ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Adaptive Controller ◽  
Stochastic Nonlinear Systems ◽  
Fuzzy Logic Systems ◽  
Adaptive Tracking Control ◽  
Adaptive Tracking

The problem of fuzzy-based direct adaptive tracking control is considered for a class of pure-feedback stochastic nonlinear systems. During the controller design, fuzzy logic systems are used to approximate the packaged unknown nonlinearities, and then a novel direct adaptive controller is constructed via backstepping technique. It is shown that the proposed controller guarantees that all the signals in the closed-loop system are bounded in probability and the tracking error eventually converges to a small neighborhood around the origin in the sense of mean quartic value. The main advantages lie in that the proposed controller structure is simpler and only one adaptive parameter needs to be updated online. Simulation results are used to illustrate the effectiveness of the proposed approach.

Strictly-lower-convex-function-constructing disturbance observer based adaptive back stepping control for hypersonic flight vehicles

2017 ◽  
Vol 232 (13) ◽  
pp. 2552-2564
Author(s):  
Jingxing Zuo ◽  
Yunjie Wu ◽  
Lianghua Sun
Keyword(s):  
Convex Function ◽  
Flight Control ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Tracking Error ◽  
Small Region ◽  
Control Laws ◽  
Hypersonic Flight ◽  
Flight Vehicles ◽  
Adaptive Laws

This study concerns with the attitude and velocity tracking control problem for the longitudinal model of hypersonic flight vehicles, which is nonlinear in aerodynamics with model uncertainties and external disturbances. By employing back stepping sliding mode method and the strictly-lower-convex-function-constructing nonlinear disturbance observer (SNDOB), a novel composite controller is proposed to guarantee the system tracking error to converge to a small region containing the origin. Besides, several proper adaptive laws are also introduced to make the controller avoid of the differential explosion problem and be chatter-free. Compared with other robust flight control approaches, key novelties of the developed method are that one new SNDOB is proposed and drawn into the virtual control laws at each step to compensate the disturbances and that adaptive laws are utilized to simplify the tedious and complicated differential operations. Finally, it is demonstrated by the simulation results that the new method exhibits not only an excellent robustness but also a better disturbance rejection performance than the convention approach.

scholarly journals Tracking error constrained robust adaptive neural prescribed performance control for flexible hypersonic flight vehicle

2017 ◽  
Vol 14 (1) ◽  
pp. 172988141668270 ◽  
Author(s):  
Zhonghua Wu ◽  
Jingchao Lu ◽  
Jingping Shi ◽  
Qing Zhou ◽  
Xiaobo Qu
Keyword(s):  
Neural Control ◽  
Tracking Error ◽  
Flight Vehicle ◽  
Model Uncertainties ◽  
Adaptive Neural Control ◽  
Prescribed Performance ◽  
Hypersonic Flight Vehicle ◽  
Hypersonic Flight ◽  
Control Scheme ◽  
Robust Adaptive

A robust adaptive neural control scheme based on a back-stepping technique is developed for the longitudinal dynamics of a flexible hypersonic flight vehicle, which is able to ensure the state tracking error being confined in the prescribed bounds, in spite of the existing model uncertainties and actuator constraints. Minimal learning parameter technique–based neural networks are used to estimate the model uncertainties; thus, the amount of online updated parameters is largely lessened, and the prior information of the aerodynamic parameters is dispensable. With the utilization of an assistant compensation system, the problem of actuator constraint is overcome. By combining the prescribed performance function and sliding mode differentiator into the neural back-stepping control design procedure, a composite state tracking error constrained adaptive neural control approach is presented, and a new type of adaptive law is constructed. As compared with other adaptive neural control designs for hypersonic flight vehicle, the proposed composite control scheme exhibits not only low-computation property but also strong robustness. Finally, two comparative simulations are performed to demonstrate the robustness of this neural prescribed performance controller.

scholarly journals Backstepping Control Based on Constrained Command Filter for Hypersonic Flight Vehicles with AOA and Actuator Constraints

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Junbao Wei ◽  
Haiyan Li ◽  
Ming Guo ◽  
Jing Li ◽  
Huang Huang
Keyword(s):  
Tracking Error ◽  
Lyapunov Stability Theory ◽  
Backstepping Control ◽  
Control Input ◽  
Tracking Errors ◽  
Hypersonic Flight ◽  
Flight Vehicles ◽  
Control Scheme ◽  
Actuator Constraints ◽  
Command Filter

An antisaturation backstepping control scheme based on constrained command filter for hypersonic flight vehicle (HFV) is proposed with the consideration of angle of attack (AOA) constraint and actuator constraints of amplitude and rate. Firstly, the HFV system model is divided into velocity subsystem and height subsystem. Secondly, to handle AOA constraint, a constrained command filter is constructed to limit the amplitude of the AOA command and retain its differentiability. And the constraint range is set in advance via a prescribed performance method to guarantee that the tracking error of the AOA meets the constraint conditions and transient and steady performance. Thirdly, the proposed constrained command filter is combined with the auxiliary system for actuator constraints, which ensures that the control input meets the limited requirements of amplitude and rate, and the system is stable. In addition, the tracking errors of the system are proved to be ultimately uniformly bounded based on the Lyapunov stability theory. Finally, the effectiveness of the proposed method is verified by simulation.

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