scholarly journals Underactuated AUV Nonlinear Finite-Time Tracking Control Based on Command Filter and Disturbance Observer

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4987 ◽  
Author(s):  
Xu ◽  
Zhang ◽  
Cao ◽  
Pang ◽  
Sun
Keyword(s):  
Finite Time ◽  
Autonomous Underwater Vehicle ◽  
Tracking Error ◽  
Three Dimensional ◽  
Path Following ◽  
Lyapunov Stability Theory ◽  
Ocean Currents ◽  
3D Tracking ◽  
Time Control ◽  
Underactuated Auv

The three-dimensional (3D) path following problem of an underactuated autonomous underwater vehicle with ocean currents disturbances is addressed in this paper. Firstly, the motion equation under the ocean currents disturbance is established, and the dynamic model of 3D tracking error is constructed based on virtual guidance method. Then, a finite-time control scheme based on super-twisting observer and command filtered backstepping technology is proposed. We adopt super-twisting observer based on finite-time theory to observe the ocean currents disturbances for improving the system robust. A command filtered backstepping is proposed to replace the differential process in the conventional backstepping method for avoiding the differential expansion problem. The filter compensation loop is designed to ensure the accuracy of the filtered signal, and the anti-integration saturation link is designed considering the influence of integral saturation. Lyapunov stability theory is used to prove the stability of the underactuated AUV. Simulation studies are conducted to show the effectiveness and robustness of the controller.

Adaptive finite-time control for stochastic nonlinear systems using multi-dimensional Taylor network

2021 ◽  
pp. 014233122110396
Author(s):  
Shan-Liang Zhu ◽  
Ming-Xin Wang ◽  
Yu-Qun Han
Keyword(s):  
Nonlinear Systems ◽  
Finite Time ◽  
Tracking Error ◽  
Small Neighborhood ◽  
Lyapunov Stability Theory ◽  
Loop System ◽  
Stochastic Nonlinear Systems ◽  
Time Control ◽  
Control Scheme ◽  
The Stability

In this paper, the problem of adaptive finite-time multi-dimensional Taylor network (MTN) control for a class of stochastic nonlinear systems is investigated. By combining the MTN-based approximate method and adaptive backstepping technique, a novel adaptive finite-time MTN control scheme is proposed. In this scheme, the MTNs are used to approximate the unknown nonlinear functions of the systems. The finite-time Lyapunov stability theory is utilized to prove the stability of the close-loop system. The proposed scheme can ensure that all signals in the closed-loop system are bounded in probability and the tracking error converges to a small neighborhood of the origin in a finite time. Three simulation examples are presented to show the effectiveness of the control scheme. It should be pointed that the adaptive MTN controller proposed in this paper has the advantages of fast computational speed and good real-time performance thanks to the simple structure of the MTN.

Virtual guidance-based finite-time path-following control of underactuated autonomous airship with error constraints and uncertainties

2020 ◽  
pp. 095441002096931
Author(s):  
Yan Wei ◽  
Pingfang Zhou ◽  
Yueying Wang ◽  
Dengping Duan ◽  
Zheng Chen
Keyword(s):  
Finite Time ◽  
Degrees Of Freedom ◽  
Three Dimensional ◽  
Small Neighborhood ◽  
Path Following ◽  
Coordinate Frame ◽  
Control Approach ◽  
Finite Time Stability ◽  
Path Following Control ◽  
Following Error

This paper addresses the finite-time three-dimensional path-following control problem for underactuated autonomous airship with error constraints and uncertainties. First, a five degrees-of-freedom path-following error model in the Serret-Frenet coordinate frame is established. By applying the finite-time stability theory, a virtual guidance-based finite-time adaptive neural backstepping path-following control approach is proposed. Barrier Lyapunov functions (BLFs) are introduced to deal with attitude error constraints. Neural networks (NNs) are presented to compensate for the uncertainties. To prevent the “explosion of complexity” in the design of the backstepping method, a finite-time convergent differentiator (FTCD) is introduced to estimate the time derivatives of virtual control signals. Stability analysis showed that all closed-loop signals are uniformly ultimately bounded, the constrained requirements on the airship attitude errors are never violated, and the path-following errors converge to a small neighborhood of the origin in a finite time. At last, simulation studies are provided to demonstrate the effectiveness of the proposed control approach.

Path Following of Underactuated Marine Underwater Vehicles in the Presence of Unknown Ocean Currents

2014 ◽  
Author(s):  
Signe Moe ◽  
Walter Caharija ◽  
Kristin Y. Pettersen ◽  
Ingrid Schjølberg
Keyword(s):  
Oil And Gas ◽  
Autonomous Underwater Vehicle ◽  
Autonomous Underwater Vehicles ◽  
Path Following ◽  
Oil And Gas Industry ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Ocean Currents ◽  
The Arctic ◽  
Ocean Current

The use of autonomous marine vehicles, and especially autonomous underwater vehicles, is rapidly increasing within several fields of study. In particular, such vehicles can be applied for sea floor mapping, oceanography, environmental monitoring, inspection and maintenance of underwater structures (for instance within the oil and gas industry) and military purposes. They are also highly suitable for operations below ice-covered areas in the Arctic. However, there are still many challenges related to making such underwater vehicles autonomous. A fundamental task of an autonomous underwater vehicle vessel is to follow a general path in the presence of unknown ocean currents. There exist several results for underwater vehicles to follow a general path when no ocean currents are present [1] and to follow a geometrically simple path such as a straight line when ocean currents affect the vehicle [2, 3], but the problem of general path following in the presence of unknown ocean currents has not been solved yet. This paper presents a method to achieve this. The results are an extension of the results in [1], and introduce a virtual Serret-Frenet reference frame that is anchored in and propagates along the desired path. The closed-loop system consists of an ocean current observer, a guidance law, a controller and an update law to drive the Serret-Frenet frame along the path, and is shown to be asymptotically stable given that certain assumptions are fulfilled. This guarantees that the autonomous underwater vehicle will converge to the desired path and move along it with the desired velocity. Simulation results are presented to verify and illustrate the theoretical results.

Robust adaptive finite-time tracking control of uncertain mechanical systems with input saturation and deadzone

2018 ◽  
Vol 41 (2) ◽  
pp. 560-572 ◽  
Author(s):  
Baofang Wang ◽  
Sheng Li ◽  
Qingwei Chen
Keyword(s):  
Finite Time ◽  
Tracking Control ◽  
Design Method ◽  
Tracking Error ◽  
Input Saturation ◽  
Mechanical Systems ◽  
Lyapunov Stability Theory ◽  
Continuous Functions ◽  
Model Uncertainties ◽  
Robust Adaptive

This paper addresses the problem of robust adaptive finite-time tracking control for a class of mechanical systems in the presence of model uncertainties, unknown external disturbances, and input nonlinearities containing saturation and deadzone. Without imposing any conditions on the model uncertainties, radial basis function neural networks are used to approximate unknown nonlinear continuous functions, and an adaptive tracking control scheme is proposed by exploiting the recursive design method. It is shown that the input saturation and deadzone model can be expressed as a simple linear system with a time-varying gain and bounded disturbance. An adaptive compensation term for the upper bound of the lumped disturbance is introduced. The semi-global finite-time uniform ultimate boundedness of the corresponding closed-loop tracking error system is proved with the help of the finite-time Lyapunov stability theory. Finally, an example is given to demonstrate the effectiveness of the proposed method.

scholarly journals Event-Triggered Fixed-Time Control for Steer-by-Wire Systems With Prespecified Tracking Performance

2021 ◽  
Author(s):  
Bingxin Ma ◽  
Gang Luo ◽  
Yongfu Wang
Keyword(s):  
Tracking Error ◽  
Output Feedback Control ◽  
Lyapunov Stability Theory ◽  
Fixed Time ◽  
Area Network ◽  
Control Input ◽  
Tracking Accuracy ◽  
Time Control ◽  
Steer By Wire ◽  
Event Triggered

Abstract This paper addresses the event-triggered output feedback control problem for (steer-by-wire) SbW systems with uncertain nonlinearity and time-varying disturbance. First, a new framework of event-triggered control systems is proposed to eliminate the jumping phenomenon of event-based control input, and the trade-off between saving communication resources and attenuating jumping phenomenon can be removed. Then, the adaptive disturbance observer and fuzzy-based state observer are developed to estimate the external disturbanceand unavailable state of augmented SbW systems, respectively. Third, an event-triggered fixed-time control is developed for SbW systems to achieve prespecified tracking accuracy while saving communication resources of the controller area network (CAN). Furthermore, theoretical analysis based on Lyapunov stability theory is provided to verify the tracking error of SbW systems can converge to the prespecified neighborhood of the origin in fixed time regardless of the initial tracking error. Finally, simulations and experiments are given to evaluate the effectiveness and superiority of the proposed methods.

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