The Course Control of Air Cushion Vehicle With Uncertainties and Input Saturation

2020 ◽  
Author(s):  
Yuanhui Wang ◽  
Xiyun Jiang ◽  
Mingyu Fu
Keyword(s):  
Dynamic System ◽  
Closed Loop ◽  
Wind Waves ◽  
Radial Basis Function Network ◽  
Input Saturation ◽  
Control Law ◽  
External Disturbances ◽  
Course Control ◽  
Air Cushion ◽  
Air Cushion Vehicle

Abstract In the presence of input saturation and unknown the internal uncertainties, external disturbances, including sea wind, waves and currents, this paper develops a course control law for the system of air cushion vehicle (ACV) using neural network and auxiliary dynamic system to improve the maneuverability and safety. In the design process of the course control law of air cushion vehicle, the two problems of input saturation and uncertainties are considered. On one hand, an effective auxiliary dynamic system is introduced to solve the input saturation problem and reduce its impact on the system. On the other hand, in order to deal with the internal and external disturbances of the system, the fully turned radial basis function network (FTRBFNN) is combined with the control law, and its adaptive ability makes the system compensate better for unknown uncertainties better than RBFNN. The stability of closed-loop system is proved by Lyapunov analysis. It is proved that the designed course control law can maintain ACV’s heading at desired value, while guaranteeing the uniform ultimate boundedness of all signals in the ACV closed-loop control system. Finally, simulations on ACV are carried out to demonstrate the effectiveness of the developed ACV course control law.

scholarly journals Variable Gain Prescribed Performance Control for Dynamic Positioning of Ships with Positioning Error Constraints

2022 ◽  
Vol 10 (1) ◽  
pp. 74
Author(s):  
Chenglong Gong ◽  
Yixin Su ◽  
Danhong Zhang
Keyword(s):  
Closed Loop ◽  
Input Saturation ◽  
Control Law ◽  
Positioning Error ◽  
Performance Bounds ◽  
External Disturbances ◽  
Performance Control ◽  
Prescribed Performance ◽  
Variable Gain ◽  
Prescribed Performance Control

In this paper, a variable gain prescribed performance control law is proposed for dynamic positioning (DP) of ships with positioning error constraints, input saturation and unknown external disturbances. The error performance index functions are designed to preset the prescribed performance bounds and the error mapping functions are constructed to incorporate the prescribed performance bounds into the DP control design. The variable gain technique is used to limit the output amplitude of the control law to avoid input saturation of the system by dynamically adjusting the control gain of the DP control law according to the positioning errors, and the error mapping function replaces the positioning error as a recursive sliding-mode surface to realize the prescribed performance control of the system and guarantee the stability of the closed-loop system with variable control gains. It has been proved that the proposed DP control law can make the uniformly ultimately boundedness of all signals in the DP closed-loop control system. The numerical simulation results illustrate that the proposed control law can make the ship’s position and heading maintain at the desired value with positioning error constraints, enhance the non-fragility of the DP control law to the perturbation of system’s parameters and improve the system’s rejection ability to external disturbances.

scholarly journals Safety-Guaranteed Course Control of Air Cushion Vehicle with Dynamic Safe Space Constraint

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Mingyu Fu ◽  
Shuang Gao ◽  
Chenglong Wang
Keyword(s):  
Space Constraint ◽  
Sliding Mode ◽  
Tracking Error ◽  
Safe Space ◽  
Adaptive Mechanism ◽  
Monitoring And Control ◽  
Course Control ◽  
Air Cushion ◽  
Air Cushion Vehicle ◽  
Safety Limit

This paper develops a safety-guaranteed course controller for air cushion vehicle (ACV). As the safety criterion, the unique safety limit of ACV including turn rate (TR) and sideslip angle (SA) changes with the speed when ACV is turning. To be more intuitive to show the change of safety limit and more convenient for safety monitoring and control, dynamic safe space of ACV is proposed. If the work point is within the safe space during the manual operation or automatic control, the sailing of ACV is safe. Then, the safety-guaranteed controller is designed to keep TR and SA within the safe space during the course control process based on the dynamic safe space constraint, terminal sliding mode control, and adaptive mechanism. The adaptive mechanism can effectively estimate the system uncertainty and external disturbances online without the requirement of their upper bounds. The proposed controller guarantees the convergence of tracking error. Simulations are implemented to demonstrate the efficacy of the designed controller.

scholarly journals Investigation of robust ship course control based on auxiliary loop method

2021 ◽  
pp. 248-252
Author(s):  
Aliya Imangazieva
Keyword(s):  
Control Law ◽  
Sea Waves ◽  
Unknown Parameters ◽  
External Disturbances ◽  
Loop Method ◽  
Wind Gusts ◽  
Course Control ◽  
External Conditions ◽  
Yaw Angle ◽  
The Mathematical Model

A novel robust control law is investigated on the problem of ship stabilization on the trajectory, which allows one to compensate perturbations in the parameters of the mathematical model of ship dynamics in cases of their changes caused by external conditions, namely: sea waves, currents, wind gusts, etc. To implement the proposed control law, only measured adjustable values are required such as the yaw angle and the control action that is the angle of the rudder of the ship. The synthesized ship course control system was investigated in MATLAB. The law of controlling the ship’s course with unknown parameters and external disturbances in the power supply is proposed. The design of the control law is based on a robust auxiliary loop algorithm and Khalil observers. The simulations illustrate the efficiency of the proposed control law.

Velocity-free attitude tracking for rigid spacecraft via bounded control

2021 ◽  
pp. 095441002110423
Author(s):  
Jian Zhang ◽  
Wen-Jie Wu ◽  
Long Liu ◽  
Dai Liu
Keyword(s):  
Angular Velocity ◽  
Tracking Control ◽  
Input Saturation ◽  
Control Law ◽  
Input Constraints ◽  
Bounded Control ◽  
External Disturbances ◽  
Attitude Tracking ◽  
Rigid Spacecraft ◽  
Attitude Tracking Control

This article investigates the attitude tracking control problem for a rigid spacecraft without angular velocity feedback, in which external disturbances, parametric uncertainties, and input saturation are considered. Initially, an angular velocity observer is developed incorporated with adaptive technique, which could tackle the unmeasurable angular velocity and system uncertainties simultaneously. By introducing adaptive updating law into the proposed observer, the synchronized uncertainties are handled such that robustness of the observer is enhanced, even in the presence of external disturbances. Further, for solving the input constraints problem, command filter and backstepping method are utilized; thus, a bounded attitude tracking control law is derived. Finally, the attitude tracking performance is evaluated by numerical examples.

Simulation Research of the Ship Course Control System

2012 ◽  
Vol 490-495 ◽  
pp. 871-875
Author(s):  
Hong Wei Gao
Keyword(s):  
Control System ◽  
Control Law ◽  
External Disturbances ◽  
Simulation Research ◽  
Internal Model Principle ◽  
Safe Navigation ◽  
System A ◽  
Course Control ◽  
Ship Control ◽  
Yaw Angle

In order to ensure the safe navigation, the ship course control problem is considered. By developing a sensitivity approach and the internal model principle to a ship control system, a course controller is designed. Simulation research shows that, by using the proposed control law, the ship can sail along the desired orientation with minimal energy when there are no current, wind and waves, while the controller can adjust the yaw angle caused by the external disturbances to the desired orientation fast.

Enhanced Composite Nonlinear Control Technique using Adaptive Control for Nonlinear Delayed Systems

2020 ◽  
Vol 13 (3) ◽  
pp. 396-404
Author(s):  
Sonal Singh ◽  
Shubhi Purwar
Keyword(s):  
Adaptive Control ◽  
Actuator Saturation ◽  
Input Saturation ◽  
Chemical Reactor ◽  
Control Technique ◽  
Control Law ◽  
Nonlinear Feedback ◽  
Composite Nonlinear Feedback ◽  
Delayed Systems ◽  
Analysis Of Stability

Background and Introduction: The proposed control law is designed to provide fast reference tracking with minimal overshoot and to minimize the effect of unknown nonlinearities and external disturbances. Methods: In this work, an enhanced composite nonlinear feedback technique using adaptive control is developed for a nonlinear delayed system subjected to input saturation and exogenous disturbances. It ensures that the plant response is not affected by adverse effect of actuator saturation, unknown time delay and unknown nonlinearities/ disturbances. The analysis of stability is done by Lyapunov-Krasovskii functional that guarantees asymptotical stability. Results: The proposed control law is validated by its implementation on exothermic chemical reactor. MATLAB figures are provided to compare the results. Conclusion: The simulation results of the proposed controller are compared with the conventional composite nonlinear feedback control which illustrates the efficiency of the proposed controller.

scholarly journals A Robust Observer—Based Adaptive Control of Second—Order Systems with Input Saturation via Dead-Zone Lyapunov Functions

Computation ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 82
Author(s):  
Alejandro Rincón ◽  
Gloria M. Restrepo ◽  
Fredy E. Hoyos
Keyword(s):  
Lyapunov Functions ◽  
Dead Zone ◽  
Tracking Error ◽  
Input Saturation ◽  
Chemical Reactor ◽  
Second Order ◽  
Control Law ◽  
Compact Set ◽  
State Variables ◽  
Robust Observer

In this study, a novel robust observer-based adaptive controller was formulated for systems represented by second-order input–output dynamics with unknown second state, and it was applied to concentration tracking in a chemical reactor. By using dead-zone Lyapunov functions and adaptive backstepping method, an improved control law was derived, exhibiting faster response to changes in the output tracking error while avoiding input chattering and providing robustness to uncertain model terms. Moreover, a state observer was formulated for estimating the unknown state. The main contributions with respect to closely related designs are (i) the control law, the update law and the observer equations involve no discontinuous signals; (ii) it is guaranteed that the developed controller leads to the convergence of the tracking error to a compact set whose width is user-defined, and it does not depend on upper bounds of model terms, state variables or disturbances; and (iii) the control law exhibits a fast response to changes in the tracking error, whereas the control effort can be reduced through the controller parameters. Finally, the effectiveness of the developed controller is illustrated by the simulation of concentration tracking in a stirred chemical reactor.

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