ℒ1 adaptive control of an aeroelastic system with unsteady aerodynamics and gust load

2016 ◽  
Vol 24 (2) ◽  
pp. 303-322 ◽  
Author(s):  
Keum W Lee ◽  
Sahjendra N Singh
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Pitch Angle ◽  
Unsteady Aerodynamics ◽  
Projection Algorithm ◽  
Control Surface ◽  
Control Law ◽  
Performance Limits ◽  
Aeroelastic System ◽  
Freestream Velocity

This paper presents the design of an ℒ1 adaptive control system for the stabilization of a two-dimensional aeroelastic system with structural nonlinearities and unsteady aerodynamics, using a single trailing-edge control surface. This model describes the plunge and pitch motion of a prototypical wing. It is assumed that its parameters are unknown and external disturbances are present. The unsteady aerodynamics are modeled with an approximation to Theodorsen's theory. The system exhibits limit cycle oscillations beyond a critical speed. Based on the ℒ1 adaptive control theory, a control law is developed for the trajectory control of the integral of the pitch angle. The control system includes a state predictor, a projection algorithm-based adaptation law designed based on the Lyapunov method, and a stabilizing control law. For the synthesis of the control law only the pitch angle and its derivative are measured. Simulation results show that in the closed-loop system, the aeroelastic vibrations are suppressed, despite parametric uncertainties and gust loads. Furthermore the performance limits of this ℒ1 adaptive law with respect to the freestream velocity and strength of gust load are examined.

scholarly journals Non-Certainty-Equivalent Adaptive Control of a Nonlinear Aeroelastic System

2010 ◽  
Vol 56 (4) ◽  
pp. 463-471 ◽  
Author(s):  
Keum Lee ◽  
Sahjendra Singh
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Certainty Equivalent ◽  
Control Surface ◽  
Limit Cycle Oscillation ◽  
Stream Velocity ◽  
Model Parameters ◽  
Control Input ◽  
Parameter Uncertainties ◽  
Aeroelastic System

Non-Certainty-Equivalent Adaptive Control of a Nonlinear Aeroelastic SystemThe development of a non-certainty-equivalent adaptive control system for the control of a nonlinear aeroelastic system is the subject of this paper. The prototypical aeroelastic wing section considered here includes structural nonlinearity and a single control surface for the purpose of control. Its dynamical model has two-degree-of-freedom and describes the plunge and pitch motion. It is assumed that the model parameters (except the sign of one of the control input coefficients) are not known. The uncontrolled aeroelastic model exhibits limit cycle oscillation beyond a critical free-stream velocity. Based on the attractive manifold, and the immersion and invariance methodologies, a non-certainty-equivalent adaptive state variable feedback control law for the trajectory tracking of the pitch angle is derived. Using the Lyapunov analysis, asymptotic convergence of the state variables to the origin is established. It is shown that the trajectory of the system converges to a manifold. The special feature of the designed control system is that the closed-loop system asymptotically recovers the performance of a deterministic controller. This cannot happen if certainty-equivalent adaptive controllers are used. Simulation results are presented which show that the control system suppresses the oscillatory responses of the system in the presence of large parameter uncertainties.

Reconfigurable Flight Control System Design Using Input-Output Information

2005 ◽  
Vol 219 (4) ◽  
pp. 277-285 ◽  
Author(s):  
S Hyung ◽  
Y Kim
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Flight Control ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Control Surface ◽  
Control Technique ◽  
Input Output ◽  
Discrete State ◽  
Output Information

An adaptive control algorithm using input-output information is proposed for designing an aircraft fault tolerant control system. An input-output model is derived on the basis of a discrete state-space system. The formulated input-output model has the same structure as the autoregressive moving average (ARMA) model does, and therefore, the conventional system identification method using recursive least square can be used to identify the system. To design a reconfigurable control system, an LQ tracker with output feedback scheme is adopted. During the recursive adaptive control process, the system model is updated periodically. The proposed algorithm is applicable to time-varying systems in real time. To validate the performance of the proposed adaptive fault tolerant control technique, numerical simulation of the high performance aircraft with control surface damage was performed.

Adaptive Control of Uncertain Gun Control System of Tank

2011 ◽  
Vol 88-89 ◽  
pp. 88-92 ◽  
Author(s):  
Lu Juan Shen ◽  
Ye Bao ◽  
Jian Ping Cai
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Gun Control ◽  
Control Law ◽  
Uncertain Parameters ◽  
Simulation Studies ◽  
Closed Loop System ◽  
Control Scheme ◽  
The Stability ◽  
Adaptive Control Law

In this paper, a class of gun control system of tank is considered with uncertain parameters and the backlash-like hysteresis which modeled by a differential equation. An adaptive control law is designed with backstepping technique. Compared to exist results on tank gun control problem , in our control scheme, the effect of backlash hysteresis is considered completely than to be linearized simply and no knowledge is assumed on the uncertain parameters. the stability of closed loop system and the tracking performance can be guaranteed by this control law. Simulation studies show that this controller is effective.

scholarly journals Design of Attitude Control System for UAV Based on Feedback Linearization and Adaptive Control

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Wenya Zhou ◽  
Kuilong Yin ◽  
Rui Wang ◽  
Yue-E Wang
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Attitude Control ◽  
Feedback Linearization ◽  
Control Law ◽  
Attitude Control System ◽  
Model Uncertainties ◽  
Performance Indexes ◽  
Attitude Dynamic ◽  
Adaptive Control Law

Attitude dynamic model of unmanned aerial vehicles (UAVs) is multi-input multioutput (MIMO), strong coupling, and nonlinear. Model uncertainties and external gust disturbances should be considered during designing the attitude control system for UAVs. In this paper, feedback linearization and model reference adaptive control (MRAC) are integrated to design the attitude control system for a fixed wing UAV. First of all, the complicated attitude dynamic model is decoupled into three single-input single-output (SISO) channels by input-output feedback linearization. Secondly, the reference models are determined, respectively, according to the performance indexes of each channel. Subsequently, the adaptive control law is obtained using MRAC theory. In order to demonstrate the performance of attitude control system, the adaptive control law and the proportional-integral-derivative (PID) control law are, respectively, used in the coupling nonlinear simulation model. Simulation results indicate that the system performance indexes including maximum overshoot, settling time (2% error range), and rise time obtained by MRAC are better than those by PID. Moreover, MRAC system has stronger robustness with respect to the model uncertainties and gust disturbance.

Characterization of typical aeroelastic sections under combined structural concentrated nonlinearities

2021 ◽  
pp. 107754632110001
Author(s):  
José Augusto I da Silva ◽  
Flávio D Marques
Keyword(s):  
Time Integration ◽  
Unsteady Aerodynamics ◽  
Nonlinear Effects ◽  
Free Play ◽  
Control Surface ◽  
Trailing Edge ◽  
Aeroelastic System ◽  
Practical Applications ◽  
Structural Nonlinearities ◽  
The Stability

Structural nonlinearities are usually present in aeroelastic systems. The analysis of this system commonly comprises a study involving only one type of nonlinearity, influencing a particular motion of the airfoil. However, practical applications of aeroelastic systems can be affected by different types of structural nonlinearities. It becomes essential to study the stability of the aeroelastic system under these conditions to assess more real operational flight procedures. In this context, this article presents an investigation of a typical aeroelastic section response with trailing edge control surface subjected to combinations of concentrated structural nonlinearities. Different nonlinear scenarios involving cubic hardening stiffness in pitching and free play, free play with preload, and slip dry friction in the trailing edge control surface motion are analyzed. The mathematical model is based on linear unsteady aerodynamics coupled to a three-dof typical aeroelastic section. Hopf bifurcations diagrams are obtained from direct time integration of the equation of motion. The post-flutter limit cycle oscillations are investigated, revealing supercritical and subcritical bifurcations. A complete parametric study of the nonlinear parameters is carried out, thereby allowing a sensitivity analysis of each nonlinear scenario. The results show that aeroelastic tailoring considering the mild post-flutter behavior can be achieved through an appropriate choice of combined nonlinear effects. Moreover, combined nonlinearities can mitigate the undesired subcritical aeroelastic responses caused by free play.

Robust Adaptive Control for Gun Control System of Tank

2011 ◽  
Vol 295-297 ◽  
pp. 270-273
Author(s):  
Jian Ping Cai ◽  
Jun Er Ma
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
External Disturbance ◽  
Robust Adaptive Control ◽  
Gun Control ◽  
Control Law ◽  
Unknown Constant ◽  
Adaptive Estimator ◽  
Robust Adaptive ◽  
The Stability

In this note, a class of gun control system of tank is considered with all uncertainties, such as unknown constant parameters, unlinearly parts, unparameterized parts, unmodeled parts, unknown external disturbance and so on. An robust adaptive control law is designed with backstepping technique. Compared to exist results on tank gun control problem , our control scheme combine the robust control and the adaptive estimator of unknown constant parameters and can compensate all uncertainties Accurately. The stability of closed loop system and the tracking performance can be guaranteed by this control law. Simulation studies show that this controller is effective.

scholarly journals Design of one non-linear adaptive control system and study of its tracking

2019 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Samiran Maiti ◽  
Achintya Das
Keyword(s):  
Adaptive Control ◽  
Control System ◽  
Nonlinear Systems ◽  
Control Method ◽  
Lyapunov Theory ◽  
System Stability ◽  
Control Law ◽  
Adaptive Control System ◽  
Convergence Properties ◽  
Variable Parameters

In this paper, an adaptive control method is proposed for a category of nonlinear systems. As the to begin with step in versatile controller plan, we select the control law which containing variable parameters. At that point select an adaption law for adjusting those parameters. We analyze the convergence properties and system stability using Lyapunov theory. The viability of the proposed approaches is appeared by implies of recreation on MATLAB.

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