scholarly journals Robust Control for Lateral and Longitudinal Channels of Small-Scale Unmanned Helicopters

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Bao Feng

Lateral and longitudinal channels are two closely related channels whose control stability influences flight performance of small-scale unmanned helicopters directly. This paper presents a robust control approach for lateral and longitudinal channels in the presence of parameter uncertainties and exogenous disturbances. The proposed control approach is performed by two steps. First, by performing system identification in frequency domain, system model of lateral and longitudinal channels can be accurately identified. Then, a robustH∞state feedback controller is designed to stabilize the helicopter in lateral and longitudinal channels simultaneously under extraneous disturbances situation. The proposed approach takes advantages that it reduces order of the controller by preestimating some parameters (like flapping angles) without sacrificing control accuracy. Numerical results show the reliability and effectiveness of the proposed method.

Author(s):  
Hao Chen ◽  
Zhenzhen Zhang ◽  
Huazhang Wang

This paper investigates the problem of robust H ∞ control for linear systems. First, the state-feedback closed-loop control algorithm is designed. Second, by employing the geometric progression theory, a modified augmented Lyapunov–Krasovskii functional (LKF) with the geometric integral interval is established. Then, parameter uncertainties and the derivative of the delay are flexibly described by introducing the convex combination skill. This technique can eliminate the unnecessary enlargement of the LKF derivative estimation, which gives less conservatism. In addition, the designed controller can ensure that the linear systems are globally asymptotically stable with a guaranteed H ∞ performance in the presence of a disturbance input and parameter uncertainties. A liquid monopropellant rocket motor with a pressure feeding system is evaluated in a simulation example. It shows that this proposed state-feedback control approach achieves the expected results for linear systems in the sense of the prescribed H ∞ performance.


Author(s):  
Hao Liu ◽  
Deyuan Liu ◽  
Jianxiang Xi ◽  
Yao Yu

A robust flight controller is proposed for the longitudinal model of generic hypersonic vehicles, whose dynamics involves nonlinearities, parameter uncertainties, and unstructured uncertainties. The proposed longitudinal controller is developed based on the standard [Formula: see text] theory and the robust compensating approach. The robust compensating approach is introduced to reduce the influences of multiple uncertainties and nonlinearities on the closed-loop control system. Compared to the [Formula: see text] control theory, these influences in the whole frequency range can be restrained. Theoretical analysis and numerical simulation results are presented to illustrate the tracking performance properties of the designed robust control approach.


2015 ◽  
Vol 18 (3) ◽  
pp. 183-191 ◽  
Author(s):  
Dac-Chi Dang ◽  
Young-Bok Kim

In this paper, the authors propose a new method of easily recognizing and regenerating robot motions used for robot motion control to perform the task of painting furniture and welding parts in small scale industries. The method is based on the process of accurate modeling, control design and experimental evaluation. In this study, the models and controllers for all joints of 3DOF robot system are obtained individually. The Robust control controller is designed to cope with uncertainties, especially the effects of the added inertia moment. In the experiment, the robust control method is compared with the existing PID control method, and the results indicate that the proposed designing method is more efficient than the traditional method.


2010 ◽  
Vol 130 (11) ◽  
pp. 1002-1009 ◽  
Author(s):  
Jorge Morel ◽  
Hassan Bevrani ◽  
Teruhiko Ishii ◽  
Takashi Hiyama

2021 ◽  
Vol 11 (5) ◽  
pp. 2312
Author(s):  
Dengguo Xu ◽  
Qinglin Wang ◽  
Yuan Li

In this study, based on the policy iteration (PI) in reinforcement learning (RL), an optimal adaptive control approach is established to solve robust control problems of nonlinear systems with internal and input uncertainties. First, the robust control is converted into solving an optimal control containing a nominal or auxiliary system with a predefined performance index. It is demonstrated that the optimal control law enables the considered system globally asymptotically stable for all admissible uncertainties. Second, based on the Bellman optimality principle, the online PI algorithms are proposed to calculate robust controllers for the matched and the mismatched uncertain systems. The approximate structure of the robust control law is obtained by approximating the optimal cost function with neural network in PI algorithms. Finally, in order to illustrate the availability of the proposed algorithm and theoretical results, some numerical examples are provided.


2013 ◽  
Vol 467 ◽  
pp. 621-626
Author(s):  
Chen Fang ◽  
Jiang Hong Shi ◽  
Kun Yu Li ◽  
Zheng Wang

For a class of uncertain generalized discrete linear system with norm-bounded parameter uncertainties, the state feedback robust control problem is studied. One sufficient condition for the solvability of the problem and the state feedback robust controller are obtained in terms of linear matrix inequalities. The designed controller guarantees that the closed-loop systems is regular, causal, stable and satisfies a prescribed norm bounded constraint for all admissible uncertain parameters under some conditions. The result of the normal discrete system can be regarded as a particular form of our conclusion. A simulation example is given to demonstrate the effectiveness of the proposed method.


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