scholarly journals OUTPUT FEEDBACK CONTROL WITH CONSTRAINTS FOR NONLINEAR SYSTEMS VIA PIECEWISE QUADRATIC OPTIMIZATION

2017 ◽  
Vol 55 (3) ◽  
pp. 324
Author(s):  
Nguyen Doan Phuoc ◽  
Pham Van Hung ◽  
Hoang Duc Quynh
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Tracking Control ◽  
Control Method ◽  
Output Feedback Control ◽  
State Feedback Control ◽  
State Observation ◽  
Output Tracking ◽  
Output Tracking Control ◽  
Wide Range

Very few output feedback control methods can be applied for a large class of nonlinear objects. If the control problem has supplementary constraints to satisfy, the number of suitable methods will be fewer. The paper proposes a nonlinear control method, which can be applied to output tracking control a wide range of various perturbed nonlinear objects. This output feedback controller is established based on piecewise quadratic optimizing subjected to input constraints for state feedback control and then combined with an appropriate EKF or UKF for system state observation. The simulation results obtained by applying this proposed controller to output tracking control inverted pendulum and boiler-turbine unit had confirmed its promising applicability in practice.

scholarly journals Modeling and nonlinear energy-based anti-swing control of underactuated dual ship-mounted cranes systems

2021 ◽  
Author(s):  
Die Hu ◽  
Yuzhe Qian ◽  
Yongchun Fang ◽  
Yuzhu Chen
Keyword(s):  
Feedback Control ◽  
Output Feedback ◽  
Control Method ◽  
Controller Design ◽  
Output Feedback Control ◽  
Geometric Constraints ◽  
State Feedback Control ◽  
State Variables ◽  
Nonlinear Controllers ◽  
Feedback Control Method

Abstract As the volume and the mass of the payload increases, it is often necessary to use two ship-mounted cranes to jointly transport huge payloads under marine environment. Compared with a single ship-mounted crane, dual ship-mounted cranes contain more state variables, geometric constraints and coupling dynamics, which bring more challenges in kinematic analysis and controller design for such complicated underactuated systems. In order to solve these problems, the dynamic model of the dual ship-mounted cranes systems are established based on Lagrange's method. Considering different practical requirements, two energy-based nonlinear controllers for dual ship-mounted cranes are developed, including a full state feedback control method and an output feedback control method. More preciously, during the control design process, the saturation constraints of the controllers have been fully considered. Meanwhile, the proposed controllers can achieve accurate positioning of the double-constrained derricks as well as effective elimination of payload swing. The stability of the equilibrium point of the closed-loop system is analyzed by using Lyapunov techniques and Lasalle's invariance principle. As far as we know, the modeling and the output feedback controller design of dual ship-mounted cranes are proposed for the first time in this paper. At the same time, the design and analysis process does not need to linearize the complex nonlinear dynamics equations, while the proposed output feedback control method is robust against the situations when the velocity signals are unknown/unavailable. Finally, a series of experiments are carried out to verify the effectiveness of the proposed nonlinear controllers.

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.

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