scholarly journals Agile Attitude Control and Singularity Avoidance/Escape by the SDRE Method Using a Biased State-Dependent Weighting Matrix

2018 ◽  
Vol 8 (1) ◽  
pp. 140 ◽  
Author(s):  
Ryotaro Ozawa ◽  
Masaki Takahashi
Keyword(s):  
Attitude Control ◽  
Singularity Avoidance ◽  
Weighting Matrix ◽  
State Dependent

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.

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.

Vibration suppression and attitude control for the formation flight of flexible satellites by optimally tuned on-off state-dependent Riccati equation approach

2020 ◽  
Vol 42 (15) ◽  
pp. 2984-3001
Author(s):  
Hossein Rouzegar ◽  
Alireza Khosravi ◽  
Pouria Sarhadi
Keyword(s):  
Riccati Equation ◽  
Attitude Control ◽  
Vibration Suppression ◽  
Pso Algorithm ◽  
Formation Flight ◽  
Equation Approach ◽  
Coordination Control ◽  
Suggested Approach ◽  
State Dependent ◽  
Highly Nonlinear

In this paper, vibration suppression and attitude control for the formation flight of flexible satellites using optimally tuned on-off SDRE (state-dependent Riccati equation) approach is discussed. A formation consisting of flexible satellites has highly nonlinear dynamics and the corresponding satellites are subject to vibrations as well as uncertainties due to the practical conditions. Vibrations that are mainly caused by flexible modes of the satellites disorganize the coordination and hinder the formation stability as well as decreasing its performance and lifetime. Hence, flexibility should be considered in formation model and the coordination control needs to address such challenges. Owing to capabilities of SDRE approach for nonlinear systems, it is used as the coordination control. Satellites are assumed to be equipped with thrusters as their actuators which requires the control to be applied as on-off pulses. To this end, an algorithm is suggested to efficiently convert SDRE control into on-off pulses. For optimal tuning of the controller, the particle swarm optimization (PSO) algorithm is employed. Stability of the system has also been analyzed via a Lyapunov-based approach utilizing the region of attraction concept. The proposed on-off SDRE approach has shown to effectively suppress the vibrations in the presence of uncertainties leading to the accurate coordination of the whole formation while consuming less energy. Simulation results show the capability, efficiency, robustness and stability of the suggested approach.

scholarly journals Composite Immersion and Invariance Based Adaptive Attitude Control of Asteroid-Orbiting Spacecraft in Elliptic Orbit

2021 ◽  
Author(s):  
Keum W Lee ◽  
Sahjendra N Singh
Keyword(s):  
Attitude Control ◽  
Closed Loop ◽  
Tracking Error ◽  
Loop System ◽  
Closed Loop System ◽  
Immersion And Invariance ◽  
State Dependent ◽  
Dependent Vector ◽  
Yaw Angle ◽  
Angle Tracking

Abstract This paper proposes a new composite noncertainty-equivalence adaptive (CNCEA) control system for the attitude (roll, pitch, and yaw angle) control of a spacecraft in an orbit around a uniformly rotating asteroid based on the immersion and invariance (I&I) theory. For the design, it is assumed that the asteroid's gravitational parameters and the spacecraft's inertia matrix are not known. In contrast to certainty-equivalence adaptive (CEA) or noncertainty-equivalence adaptive (NCEA) systems, the CNCEA attitude control system's composite identifier uses the attitude angle tracking error, a nonlinear state-dependent vector function, and model prediction error for parameter estimation. The Lyapunov analysis shows that in the closed-loop system, the Euler angles asymptotically track the reference attitude trajectories. Interestingly, there exist two parameter error-dependent attractive manifolds, to which the closed-loop system's trajectories converge. Moreover, the composite identifier using two types of error signals provides stronger stability properties in the closed-loop system. Simulation results are presented for the attitude control of a spacecraft orbiting in the vicinity of the asteroid 433 Eros. These results show precise nadir pointing attitude regulation, despite uncertainties in the system.

Sign in / Sign up

Export Citation Format

Share Document