Control law design to improve the unexpected pitch motion in slow down turn maneuver

2021 ◽  
pp. 095441002110086
Author(s):  
Chong-sup Kim ◽  
Taebeom Jin ◽  
Gi-oak Koh ◽  
Byoung soo Kim
Keyword(s):  
Control System ◽  
Angular Acceleration ◽  
Control Law ◽  
Fighter Aircraft ◽  
Pitch Motion ◽  
Flying Qualities ◽  
Aircraft System ◽  
The Stability ◽  
The Time Domain ◽  
The Mathematical Model

The highly maneuverable fighter aircraft is exposed to unexpected pitch motion such as over-Nz (normal acceleration) and Nz-drop characteristics in transonic and supersonic flight conditions with moderate angle of attack. These characteristics not only degrade flying qualities by destabilizing the aircraft but also threaten flight safety by increasing the structural load. This article proposes an additional augmentation control in the incremental nonlinear dynamic inversion structure, which feeds back the error of pitch angular acceleration to mitigate unexpected pitch motion in slow down turn maneuver. We evaluate the stability, flying qualities, and robustness of the proposed control system by performing the frequency-domain linear analysis and the time-domain numerical simulations based on the mathematical model of advanced trainer aircraft. As a result of the evaluation, the additional augmentation control further improves flying qualities and deceleration performance of the aircraft by decreasing over-Nz and Nz-drop characteristics in high-Nz maneuvering in the transonic flight condition as well as ensuring the stability and robustness of the control system against the major uncertainty factors of the aircraft system compared to the existing transonic pitching moment compensation (TPMC) control in which the predefined scheduling for Nz feedback is used.

Development of a control law to improve the handling qualities for short-range air-to-air combat maneuvers

2020 ◽  
Vol 12 (7) ◽  
pp. 168781402093679
Author(s):  
Chong-Sup Kim ◽  
Chang-Ho Ji ◽  
Byoung Soo Kim
Keyword(s):  
Flight Control ◽  
Short Range ◽  
Control Method ◽  
Control Law ◽  
Fighter Aircraft ◽  
Handling Qualities ◽  
Flying Qualities ◽  
Air Combat ◽  
Handling Quality ◽  
The Mathematical Model

Modern fighter aircraft have been designed to have high maneuverability in order to preoccupy strategic superiority in short-range air-to-air combat between fighter aircraft in warfare. Digital fly-by-wire flight control system design is aimed at providing good handling qualities for all mission task elements over the entire flight envelope. To provide both excellent gross acquisition and fine tracking compatibility, simultaneously for air-to-air combat maneuvers, this article presents a common longitudinal control law design of a task-dependent self-adjusting command-path pilot prefilter gain scheduler within the same control law design architecture and response type based on nonlinear dynamic inversion control. We perform the frequency- and time-domain analyses based on the mathematical model of T-50 advanced trainer aircraft to evaluate the basic flying qualities of the proposed control method. Furthermore, the pilot evaluation is performed to evaluate the gross acquisition and fine tracking capability for air-to-air tracking maneuvers in a handling quality simulator. The evaluation results reveal that the proposed control method improves the fine tracking capability without the degradation of gross acquisition.

Pointwise Optimal Control of Dynamical Systems Described by Constrained Coordinates

1999 ◽  
Vol 121 (4) ◽  
pp. 594-598 ◽  
Author(s):  
V. Radisavljevic ◽  
H. Baruh
Keyword(s):  
Optimal Control ◽  
Dynamical Systems ◽  
Feedback Control ◽  
Degrees Of Freedom ◽  
Equations Of Motion ◽  
Differential Algebraic Equations ◽  
Control Law ◽  
Algebraic Equations ◽  
The Stability ◽  
The Mathematical Model

A feedback control law is developed for dynamical systems described by constrained generalized coordinates. For certain complex dynamical systems, it is more desirable to develop the mathematical model using more general coordinates then degrees of freedom which leads to differential-algebraic equations of motion. Research in the last few decades has led to several advances in the treatment and in obtaining the solution of differential-algebraic equations. We take advantage of these advances and introduce the differential-algebraic equations and dependent generalized coordinate formulation to control. A tracking feedback control law is designed based on a pointwise-optimal formulation. The stability of pointwise optimal control law is examined.

scholarly journals Robust dynamic inversion control of flight control system based on L1 adaptive structure

2021 ◽  
Vol 39 (5) ◽  
pp. 995-1004
Author(s):  
Yu LI ◽  
Xiaoxiong LIU ◽  
Ruichen MING ◽  
Shaoshan SUN ◽  
Weiguo ZHANG
Keyword(s):  
Control System ◽  
Flight Control ◽  
Dynamic Performance ◽  
Dynamic Inversion ◽  
Control Law ◽  
Flight Control System ◽  
Parameter Uncertainties ◽  
Strong Robustness ◽  
Adaptive Structure ◽  
The Stability

Nonlinear Dynamic Inversion(NDI) control has excellent rapidity and decoupling ability, unfortunately it lacks the essential robustness to disturbance. From the perspective of enhancing the robustness, an adaptive NDI method based on L1 adaptive structure is proposed. The L1 adaptive structure is introduced into the NDI control to enhance its robustness, which also guarantees the stability and expected dynamic performance of the system suffering from the disturbance influence. Secondly, the flight control law of the advanced aircraft is designed based on the present method to improve the robustness and fault tolerance of the flight control system. Finally, the effectiveness of the flight control law based on the present approach is verified under the fault disturbance. The results showed that the flight control law based on L1 adaptive NDI has excellent dynamic performance and strong robustness to parameter uncertainties and disturbances.

LQG-Based Robustifying Flight Control System

2003 ◽  
Author(s):  
D. Griffin ◽  
A. G. Kelkar
Keyword(s):  
Control System ◽  
Flight Control ◽  
Controller Design ◽  
Second Step ◽  
Flight Control System ◽  
Robust Controller ◽  
Fighter Aircraft ◽  
Stability Robustness ◽  
Uncertainty Model ◽  
The Stability

This paper presents a robust controller design for an automatic flight control system (AFCS) for a fighter aircraft model with eight inputs and seven outputs. The controller is designed based on McFarlane-Glover robustifying technique using a simple baseline LQG design. Controllers designed purely based on traditional LQG techniques are known to have no guaranteed robustness margins. The McFarlane-Glover technique can be used to enhance the stability robustness of the baseline LQG design using a two-step design process. In the first step, an LQG controller is designed which is optimized only for performance without any consideration to robustness. In the second step, the performance optimized LQG design is rendered robust using McFarlane-Glover procedure. The robustifying procedure uses a coprime factor uncertainty model and H∞ optimization. An important advantage of this procedure is that no problem dependent uncertainty modelling or weight selection is required in the second step of the process. The robustifying procedure also yields the quantitative estimate of the robustness.

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.

Optimization of Satellite Momentum Wheel Control System Based on Genetic Programming

2013 ◽  
Vol 748 ◽  
pp. 771-778
Author(s):  
Yu Song Huang ◽  
Yun Feng Dong
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Genetic Programming ◽  
Design Process ◽  
Attitude Control ◽  
Control Method ◽  
Complex Structure ◽  
Control Law ◽  
Reaction Wheel ◽  
The Mathematical Model

Due to reliability requirements, the reaction wheel actuator of the satellite attitude control system always use traditional control method. For the satellite which has complex structure, it's difficult to build the mathematical model with classical control method. The selection of control parameters is also difficult. The design process last long and the model have poor adaptability when the parameters change. Compare to genetic algorithms, genetic programming which have the capabilities to evolve automatically, have the advantage of being able to optimize the structure of the mathematical model. Results of optimization and simulation show that design the reaction wheel actuator control law with genetic programming can simplify the design process. And the evolved control law is better than traditional PD control law.

Modeling and Attitude Control of a Spinning Spacecraft with Internal Moving Mass

2013 ◽  
Vol 760-762 ◽  
pp. 1216-1220 ◽  
Author(s):  
Peng Fei Guo ◽  
Liang Yu Zhao
Keyword(s):  
Nonlinear Dynamics ◽  
Control System ◽  
Attitude Control ◽  
Linear Quadratic Regulator ◽  
Control Law ◽  
Moving Mass ◽  
Newtonian Mechanics ◽  
Attitude Control System ◽  
Linear Quadratic ◽  
The Mathematical Model

An attitude control system of a spinning spacecraft with internal moving mass is presented in this paper. This system consists of a rigid body and two internal radial moving masses. The mathematical model, including attitude kinematics and nonlinear dynamics equations, is established based on Newtonian mechanics. The control law is designed based on the linear-quadratic-regulator (LQR) theory. The performance of the controller is demonstrated in numerical simulation, and the response shows that the attitude control system is stable and effective.

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.

Analysis on Influence of Dynamic Setting AGC Model Parameters on the Stability of Control System

2010 ◽  
Vol 145 ◽  
pp. 128-133
Author(s):  
Chun Jiang Zhao ◽  
Lian Yun Jiang ◽  
Jin Zhi Zhang ◽  
Qing Xue Huang ◽  
Xiao Kai Yu
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Convergence Rate ◽  
Mathematical Analysis ◽  
Stability And Convergence ◽  
Model Parameters ◽  
Recursive Methods ◽  
Dynamic Setting ◽  
The Stability ◽  
The Mathematical Model

Based on the theory of mathematical analysis, I find the rolling disturbance can be measured. Then the mathematical model of dynamic setting AGC is gotten by recursive methods. By the mathematical model I find out the influence of model parameters on the stability and convergence rate of the control system. When the system is stable, an influence of model parameters and parameter of the control system on steel strap thickness have been obtained, which will be helpful for us to choose suitable parameters in the end.

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