Automatic Flight Control of Unmanned Helicopter Based on Nonlinear Model

2012 ◽  
Vol 472-475 ◽  
pp. 1492-1499
Author(s):  
Run Xia Guo
Keyword(s):  
Nonlinear Model ◽  
Flight Control ◽  
Attitude Control ◽  
Lyapunov Stability Theory ◽  
Test Results ◽  
Unmanned Helicopter ◽  
Control Laws ◽  
Control Approach ◽  
State Dependent ◽  
Compensation Technique

The Unmanned helicopter (UMH) movement was divided into two parts, namely, attitude and trajectory motion. And then a two-timescale nonlinear model was established. The paper improved and expanded state dependent riccati equation (SDRE) control approach, deriving analytical conditions for achieving global asymptotic stability with lyapunov stability theory. Proof was given. By combining improved SDRE control with nonlinear feed-forward compensation technique, the full envelop flight attitude control laws could be designed. On the basis of attitude control, trajectory controller was developed. Actual flight tests were carried out. Test results show that the control strategy is highly effective.

Vehicle Traction Control: Variable-Structure Control Approach

1991 ◽  
Vol 113 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Han-Shue Tan ◽  
Yuen-Kwok Chin
Keyword(s):  
Sliding Mode ◽  
Control Variable ◽  
Sufficient Conditions ◽  
Variable Structure ◽  
Lyapunov Stability Theory ◽  
Vehicle Model ◽  
Control Laws ◽  
Traction Control ◽  
Control Approach ◽  
Structure Control

A longitudinal one-wheel vehicle model is described for both anti-lock braking and anti-span acceleration. Based on this vehicle model, sufficient conditions for applying sliding-mode control to vehicle traction are derived via Lyapunov Stability Theory. With the understanding of these sufficient conditions, control laws are designed to control vehicle traction. Both the sufficient conditions and the control laws are verified using computer simulations.

Robust nonlinear H∞ output-feedback control for flexible spacecraft attitude manoeuvring

2019 ◽  
Vol 41 (7) ◽  
pp. 2026-2038 ◽  
Author(s):  
Huihui Bai ◽  
Chunqing Huang ◽  
Jianping Zeng
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Attitude Control ◽  
Output Feedback Control ◽  
Lyapunov Stability Theory ◽  
Flexible Spacecraft ◽  
Matrix Perturbation ◽  
External Disturbances ◽  
Convex Optimization Problem ◽  
Control Approach

This paper presents a robust nonlinear H∞ output-feedback control approach for attitude manoeuvring of flexible spacecraft with external disturbances, inertia matrix perturbation and input constraints. By applying Lyapunov stability theory and using the generalized S-procedure and sum of squares (SOS) techniques, the robust H∞ output-feedback attitude control problem is converted into a convex optimization problem with SOS constraints when the flexible spacecraft is modelled as a polynomial state-space equation with polytope uncertainties. As a result, it overcomes the difficulty in constructing Lyapunov function and implementing numerical computation caused by the non-convexity of output-feedback H∞ control design for nonlinear systems. Moreover, it enables the state-observer and the controller to be designed independently and hence the complexity of the control algorithm is reduced remarkably. A numerical example illustrates the effectiveness and feasibility of the proposed approach.

Magnetically Suspended VSCMGs for Simultaneous Attitude Control and Power Transfer IPAC Service

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Junyoung Park ◽  
Alan Palazzolo
Keyword(s):  
Attitude Control ◽  
High Speed ◽  
System Modeling ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Power Transfer ◽  
Variable Speed ◽  
Control Laws ◽  
Control Approach ◽  
Initial Attitude

This paper presents the theory and numerical results of utilizing four gimbaled, magnetically suspended, variable speed flywheels for simultaneous satellite attitude control and power transfer (charge, storage, and delivery). Previous variable speed control moment gyro models and control algorithms assumed that the flywheel bearings were rigid. However, high speed flywheels on spacecraft will be supported by active magnetic bearings, which have flexibility and in general frequency dependent characteristics. The present work provides the theory for modeling the satellite and flywheel systems including controllers for stable magnetic bearing suspension for power transfer to and from the flywheels and for attitude control of the satellite. A major reason for utilizing flexible bearings is to isolate the imbalance disturbance forces from the flywheel to the satellite. This g-jitter vibration could interfere with the operation of sensitive onboard instrumentation. A special control approach is employed for the magnetic bearings to reject the imbalance disturbances. The stability, robustness, tracking, and disturbance rejection performances of the feedback control laws are demonstrated with a satellite simulation that includes initial attitude error, system modeling error, and flywheel imbalance disturbance.

Suboptimal Control Theory for Vehicle Attitude Control System Design

2012 ◽  
Vol 466-467 ◽  
pp. 976-980
Author(s):  
Guo Long Fan ◽  
Xiao Geng Liang ◽  
Yong Hua Fan
Keyword(s):  
Control System ◽  
Lyapunov Stability ◽  
Flight Control ◽  
Attitude Control ◽  
Stability Theory ◽  
Deflection Angle ◽  
Lyapunov Stability Theory ◽  
Suboptimal Control ◽  
System Control ◽  
Flight Control System

Base on the Lyapunov stability theory, an improved suboptimal control system scheme is advanced in this paper. Aiming at hypersonic reentry vehicle nonlinear properties of the actuator deflection angle rate and the deflection angle were studied. First, the mathematical model of the control system is established according to the flight control system control scheme. Considering the project realize easy, the flight control system is designed based on suboptimal control of Lyapunov stability theory. In order to close to the optimal control, then the suboptimal control design is improved. Finally the controller is applied to the instances, by analyzing the results confirmed the method is correctly.

scholarly journals SDRE and LQR Controls Comparison Applied in High-Performance Aircraft in a Longitudinal Flight

2021 ◽  
Vol 1 (2) ◽  
pp. 131-144
Author(s):  
Guilherme P. Dos Santos ◽  
Adriano Kossoski ◽  
Jose M. Balthazar ◽  
Angelo Marcelo Tusset
Keyword(s):  
Nonlinear Model ◽  
Flight Control ◽  
High Performance ◽  
Large Range ◽  
Angle Of Attack ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
State Dependent ◽  
Stall Angle ◽  
Difficult Situations

This paper presents the design of the LQR (Linear Quadratic Regulator) and SDRE (State-Dependent Riccati Equation) controllers for the flight control of the F-8 Crusader aircraft considering the nonlinear model of longitudinal movement of the aircraft.  Numerical results and analysis demonstrate that the designed controllers can lead to significant improvements in the aircraft's performance, ensuring stability in a large range of attack angle situations. When applied in flight conditions with an angle of attack above the stall situation and influenced by the gust model, it was demonstrated that the LQR and SDRE controllers were able to smooth the flight response maintaining conditions in balance for an angle of attack up to 56% above stall angle.  However, for even more difficult situations, with angles of attack up to 76% above the stall angle, only the SDRE controller proved to be efficient and reliable in recovering the aircraft to its stable flight configuration.

Design and flight test of active flutter suppression on the X-56A multi-utility technology test-bed aircraft

2016 ◽  
Vol 120 (1228) ◽  
pp. 893-909 ◽  
Author(s):  
E. L. Burnett ◽  
J. A. Beranek ◽  
B. T. Holm-Hansen ◽  
C. J. Atkinson ◽  
P. M. Flick
Keyword(s):  
Flight Control ◽  
Flight Test ◽  
Test Bed ◽  
Control Laws ◽  
Control Approach ◽  
Mode Control ◽  
Flying Qualities ◽  
Technical Challenges ◽  
Long Endurance ◽  
Aircraft Configurations

ABSTRACTEfforts to develop the next generation of aircraft with ever-increasing levels of performance – higher, farther, faster, cheaper – face great technical challenges. One of these technical challenges is to reduce structural weight of the aircraft. Another is to look to aircraft configurations that have been unrealizable to date. Both of these paths can lead to a rigid flex coupling phenomenon that can result in anything from poor flying qualities to the loss of an aircraft due to flutter. This has led to a need to develop an integrated flight and aeroelastic control capability where structural dynamics are included in the synthesis of flight control laws. Studies have indicated that the application of an integrated flight and aeroelastic control approach to a SensorCraft high-altitude long-endurance vehicle would provide substantial performance improvement(1,2). Better flying qualities and an expanded flight envelope through multi-flutter mode control are two areas of improvement afforded by integrated flight and aeroelastic control. By itself, multi-flutter mode control transforms the flutter barrier from a point of catastrophic structural failure to a benign region of flight. This paper discusses the history and issues associated with the development of such an integrated flight and aeroelastic control system for the X-56A aircraft.

scholarly journals Design of Satellite Attitude Control Algorithm Based on the SDRE Method Using Gas Jets and Reaction Wheels

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Luiz C. G. de Souza ◽  
Victor M. R. Arena
Keyword(s):  
Attitude Control ◽  
Control Algorithm ◽  
Controller Design ◽  
Algorithm Design ◽  
Large Angle ◽  
Space Mission ◽  
Control Technique ◽  
Gas Jets ◽  
State Dependent ◽  
Highly Nonlinear

An experimental attitude control algorithm design using prototypes can minimize space mission costs by reducing the number of errors transmitted to the next phase of the project. The Space Mechanics and Control Division (DMC) of INPE is constructing a 3D simulator to supply the conditions for implementing and testing satellite control hardware and software. Satellite large angle maneuver makes the plant highly nonlinear and if the parameters of the system are not well determined, the plant can also present some level of uncertainty. As a result, controller designed by a linear control technique can have its performance and robustness degraded. In this paper the standard LQR linear controller and the SDRE controller associated with an SDRE filter are applied to design a controller for a nonlinear plant. The plant is similar to the DMC 3D satellite simulator where the unstructured uncertainties of the system are represented by process and measurements noise. In the sequel the State-Dependent Riccati Equation (SDRE) method is used to design and test an attitude control algorithm based on gas jets and reaction wheel torques to perform large angle maneuver in three axes. The SDRE controller design takes into account the effects of the plant nonlinearities and system noise which represents uncertainty. The SDRE controller performance and robustness are tested during the transition phase from angular velocity reductions to normal mode of operation with stringent pointing accuracy using a switching control algorithm based on minimum system energy. This work serves to validate the numerical simulator model and to verify the functionality of the control algorithm designed by the SDRE method.

String Instabilities in Formation Flight: Limitations Due to Integral Constraints

2004 ◽  
Vol 126 (4) ◽  
pp. 873-879 ◽  
Author(s):  
P. Seiler ◽  
A. Pant ◽  
J. K. Hedrick
Keyword(s):  
Flight Control ◽  
Formation Control ◽  
Energy Savings ◽  
Feedback Loops ◽  
Formation Flight ◽  
Control Laws ◽  
Aerodynamic Efficiency ◽  
Preceding Vehicle ◽  
Specific Control ◽  
Theoretical Results

Flying in formation improves aerodynamic efficiency and, consequently, leads to an energy savings. One strategy for formation control is to follow the preceding vehicle. Many researchers have shown through simulation results and analysis of specific control laws that this strategy leads to amplification of disturbances as they propagate through the formation. This effect is known as string instability. In this paper, we show that string instability is due to a fundamental constraint on coupled feedback loops. The tradeoffs imposed by this constraint imply that predecessor following is an inherently poor strategy for formation flight control. Finally, we present two examples that demonstrate the theoretical results.

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