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.

scholarly journals Output Feedback Control for Asymptotic Stabilization of Spacecraft with Input Saturation

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Chutiphon Pukdeboon
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Control Method ◽  
Input Saturation ◽  
Output Feedback Control ◽  
Velocity Measurements ◽  
External Disturbances ◽  
Nonlinear Disturbance Observer ◽  
Rigid Spacecraft ◽  
Actuator Constraints

This paper investigates the attitude stabilization problem of rigid spacecraft subject to actuator constraints, external disturbances, and attitude measurements only. An output feedback control framework with input saturation is proposed to solve this problem. The general saturation function is utilized in the proposed controller design and a unified control method is developed for the asymptotic stabilization of rigid spacecraft without velocity measurements. Asymptotic stability is proven by Lyapunov stability theory. Moreover, a new nonlinear disturbance observer is designed to compensate for external disturbances. Then, a composite controller is presented by combining a unified saturated output feedback control with a nonlinear disturbance observer. Desirable features of the proposed control scheme include the intuitive structure, robustness against external disturbances, avoidance of model information and velocity measurements, and ability to ensure that the actuator constraints are not violated. Finally, numerical simulations have been carried out to verify the effectiveness of the proposed control method.

Delayed Output Feedback Control for Nonlinear Systems With Fuzzy Observers

2012 ◽  
Author(s):  
Mansour Karkoub ◽  
Tzu Sung Wu
Keyword(s):  
Feedback Control ◽  
Nonlinear System ◽  
Nonlinear Systems ◽  
Output Feedback ◽  
Tracking Error ◽  
Sufficient Conditions ◽  
Output Feedback Control ◽  
Linear Matrix ◽  
External Disturbances ◽  
Control Scheme

In this paper, the design problem of delayed output feedback control scheme using two-layer interval fuzzy observers for a class of nonlinear systems with state and output delays is investigated. The Takagi-Sugeno type fuzzy linear model with an on-line update law is used to approximate the nonlinear system. Based on the fuzzy model, a two-layer interval fuzzy observer is used to reconstruct the system states according to equal interval output time delay slices. Subsequently, a delayed output feedback adaptive fuzzy controller is developed to override the nonlinearities, time delays, and external disturbances such that the H∞ tracking performance is achieved. The linguistic information is developped by setting the membership functions of the fuzzy logic system and the adaptation parameters to estimate the model uncertainties directly for using linear analytical results instead of estimating nonlinear system functions. The filtered tracking error dynamics are designed to satisfy the Strictly Positive Realness (SPR) condition. Based on the Lyapunov stability criterion and linear matrix inequalities (LMIs), some sufficient conditions are derived so that all states of the system are uniformly ultimately bounded and the effect of the external disturbances on the tracking error can be attenuated to any prescribed level and consequently an H∞ tracking control is achieved. Finally, a numerical example of a two-link robot manipulator is given to illustrate the effectiveness of the proposed control scheme.

Output Feedback Control Design for Quadrotors in the Presence of Uncertainties

2015 ◽  
Author(s):  
Joonho Lee ◽  
Jongeun Choi
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Time Scale ◽  
Output Feedback Control ◽  
Control Design ◽  
High Gain ◽  
Singular Perturbation Method ◽  
External Disturbances ◽  
System States ◽  
Input Uncertainties

This paper proposes an output feedback control design for quadrotor Unmanned Aerial Vehicles (UAVs) to deal with unmeasured system states, system uncertainties, and external disturbances. Extended High-Gain Observers (EHGOs) are used to estimate the uncertainties and unmeasured system states. Dynamic inversion utilizes the estimates from EHGOs in the second and third fastest time scales in order to deal with input uncertainties and a form of non-affine control inputs. In plant dynamics, rotational dynamics in the fourth fastest time scale, is forced to be faster than translational dynamics in the slowest time scale to overcome the lack of the number of control inputs in this underactuated mechanical system. Using the singular perturbation method, stability of the closed-loop system is conducted. Throughout numerical simulations, the proposed control algorithm is verified.

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