scholarly journals Disturbance Observer-Based Path Following Control of Unmanned Surface Vessel with Control Input Saturation and Unknown Disturbance

2020 ◽  
Vol 440 ◽  
pp. 022062
Author(s):  
Yangliu Xie ◽  
Fuyu Luo ◽  
Jiangfeng Zeng ◽  
Xu Liang ◽  
Xiaoye Guo
Keyword(s):  
Disturbance Observer ◽  
Input Saturation ◽  
Path Following ◽  
Control Input ◽  
Path Following Control ◽  
Unmanned Surface Vessel ◽  
Unknown Disturbance ◽  
Surface Vessel

scholarly journals Robust Adaptive Path Following Control of an Unmanned Surface Vessel Subject to Input Saturation and Uncertainties

2019 ◽  
Vol 9 (9) ◽  
pp. 1815 ◽  
Author(s):  
Yunsheng Fan ◽  
Hongyun Huang ◽  
Yuanyuan Tan
Keyword(s):  
Adaptive Control ◽  
Finite Time ◽  
Input Saturation ◽  
Path Following ◽  
Robust Adaptive Control ◽  
Time Varying ◽  
Path Following Control ◽  
Unmanned Surface Vessel ◽  
Robust Adaptive ◽  
Surface Vessel

This paper investigates the path following control problem of an unmanned surface vessel (USV) subject to input saturation and uncertainties including model parameters uncertainties and unknown time-varying external disturbances. A nonlinear robust adaptive control scheme is proposed to address the issue, more specifically, steering a USV to follow the desired path at a certain velocity assignment despite the involved disturbances, by utilizing the finite-time currents observer based line-of-sight (LOS) guidance and radial basis function neural networks (RBFNN). Backstepping and Lyapunov’s direct method are the main design frameworks. Based on the finite-time currents observer and adaptive control technique, an improved LOS guidance law is proposed to obtain the desired approaching angle to the desired path, making compensations for the effects of unknown time-varying ocean currents. Then, a kinetic controller with the capability of uncertainties estimation and disturbances rejection is proposed based on the RBFNNs, where the adaptive laws including leakage terms estimate the approximation error and the unknown time-varying disturbances. Subsequently, sophisticated auxiliary control systems are employed to handle input saturation constraints of actuators. All error signals of the closed-loop system are proved to be locally uniformly ultimately bounded (UUB). Numerical simulations demonstrated the effectiveness and robustness of the proposed path following control method.

scholarly journals Finite-Time Path Following Control of an Underactuated Marine Surface Vessel with Input and Output Constraints

2020 ◽  
Vol 10 (18) ◽  
pp. 6447
Author(s):  
Mingyu Fu ◽  
Lulu Wang
Keyword(s):  
Finite Time ◽  
Input Saturation ◽  
Path Following ◽  
Parametric Uncertainties ◽  
External Disturbances ◽  
Time Path ◽  
Path Following Control ◽  
Control Scheme ◽  
Marine Surface ◽  
Surface Vessel

This paper develops a finite-time path following control scheme for an underactuated marine surface vessel (MSV) with external disturbances, model parametric uncertainties, position constraint and input saturation. Initially, based on the time-varying barrier Lyapunov function (BLF), the finite-time line-of-sight (FT-LOS) guidance law is proposed to obtain the desired yaw angle and simultaneously constrain the position error of the underactuated MSV. Furthermore, the finite-time path following constraint controllers are designed to achieve tracking control in finite time. Additionally, considering the model parametric uncertainties and external disturbances, the finite-time disturbance observers are proposed to estimate the compound disturbance. For the sake of avoiding the input saturation and satisfying the requirements of finite-time convergence, the finite-time input saturation compensators were designed. The stability analysis shows that the proposed finite-time path following control scheme can strictly guarantee the constraint requirements of the position, and all error signals of the whole control system can converge into a small neighborhood around zero in finite time. Finally, comparative simulation results show the effectiveness and superiority of the proposed finite-time path following control scheme.

scholarly journals Neural observer-based path following control for underactuated unmanned surface vessels with input saturation and time-varying disturbance

2019 ◽  
Vol 16 (5) ◽  
pp. 172988141987807
Author(s):  
Lei Wan ◽  
Jiangfeng Zeng ◽  
Yueming Li ◽  
Hongde Qin ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Disturbance Observer ◽  
External Disturbance ◽  
Input Saturation ◽  
Path Following ◽  
Dynamic Surface Control ◽  
Dynamic Surface ◽  
Surface Control ◽  
Surface Vessels ◽  
Path Following Control ◽  
Control Scheme

In this study, a new neural observer-based dynamic surface control scheme is proposed for the path following of underactuated unmanned surface vessels in the presence of input saturation and time-varying external disturbance. The dynamic surface control technique is augmented by a robust adaptive radial basis function neural network and a nonlinear neural disturbance observer. Radial basis function neural network is employed to deal with system uncertainties, and the nonlinear neural disturbance observer is developed to compensate for the unknown compound disturbance that contains the input saturation approximation error and the external disturbance. Moreover, the stringent known boundary requirement of the unknown disturbance constraint is eliminated with the proposed nonlinear neural disturbance observer. Meanwhile, to deal with the non-smooth saturation nonlinearity, a new parametric hyperbolic tangent function approximation model with arbitrary prescribed precision is constructed, which results in the transient performance improvement for the path following control system. Stability analysis shows that all the signals in the closed-loop system are guaranteed to be ultimately bounded. Comparative simulation results further demonstrate the effectiveness of the proposed control scheme.

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