Improved BP Algorithm Applied to Motion Control of UV

2013 ◽  
Vol 446-447 ◽  
pp. 1183-1187
Author(s):  
Jian Guo Wang ◽  
Gang Yi Hu ◽  
Chun Meng Jiang
Keyword(s):  
Neural Networks ◽  
Motion Control ◽  
Underwater Vehicle ◽  
Bp Algorithm ◽  
Learning Mechanism ◽  
Main Target ◽  
Research Objects ◽  
The Stability ◽  
Improved Bp Algorithm ◽  
Least Disturbance

Up to now, some technologies of neural networks are developed to solve the non-linearity of research objects and the adaptive control is implemented in many engineering fields, and some good results are achieved. Though the learning mechanism of neural networks is really unknowable, the importance of study ratio is widely realized, and some methods on modification of study ratio are provided. Improving the stability and increasing the convergent rate of networks by defining a good form of study ratio is the main target. A new algorithm named least disturbance BP algorithm is proposed to calculate the ratio online according to the output errors, the weights of network and the input values. The algorithm is applied to the control of an underwater vehicle. The good performance of the algorithm and the controller is demonstrated by the experimental results.

scholarly journals Saturation Based Nonlinear FOPD Motion Control Algorithm Design for Autonomous Underwater Vehicle

2019 ◽  
Vol 9 (22) ◽  
pp. 4958 ◽  
Author(s):  
Lichuan Zhang ◽  
Lu Liu ◽  
Shuo Zhang ◽  
Sheng Cao
Keyword(s):  
Control System ◽  
Motion Control ◽  
Simple Structure ◽  
Autonomous Underwater Vehicle ◽  
Dynamic Performance ◽  
Dynamic Control ◽  
Algorithm Design ◽  
Underwater Vehicle ◽  
Motion Control System ◽  
The Stability

The application of Autonomous Underwater Vehicle (AUV) is expanding rapidly, which drives the urgent need of its autonomy improvement. Motion control system is one of the keys to improve the control and decision-making ability of AUVs. In this paper, a saturation based nonlinear fractional-order PD (FOPD) controller is proposed for AUV motion control. The proposed controller is can achieve better dynamic performance as well as robustness compared with traditional PID type controller. It also has the advantages of simple structure, easy adjustment and easy implementation. The stability of the AUV motion control system with the proposed controller is analyzed through Lyapunov method. Moreover, the controlled performance can also be adjusted to satisfy different control requirements. The outperformed dynamic control performance of AUV yaw and depth systems with the proposed controller is shown by the set-point regulation and trajectory tracking simulation examples.

scholarly journals Performance Analysis on Depth and Straight Motion Control based on Control Surface Combinations for Supercavitating Underwater Vehicle

2021 ◽  
Vol 24 (4) ◽  
pp. 435-448
Author(s):  
Beomyeol Yu ◽  
Hyemin Mo ◽  
Seungkeun Kim ◽  
Jong-Hyon Hwang ◽  
Jeong-Hoon Park ◽  
...  
Keyword(s):  
Motion Control ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Underwater Vehicle ◽  
Control Surface ◽  
Control Performance ◽  
Friction Resistance ◽  
Control Loops ◽  
The Stability ◽  
And Control

This study describes the depth and straight motion control performance depending on control surface combinations of a supercavitating underwater vehicle. When an underwater vehicle experiences supercavitation, friction resistance can be minimized, thus achieving the effect of super-high-speed driving. Six degrees of freedom modeling of the underwater vehicle are performed and the guidance and control loops are designed with not only a cavitator and an elevator, but also a rudder and a differential elevator to improve the stability of the roll and yaw axis. The control performance based on the combination of control surfaces is analyzed by the root-mean-square error for keeping depth and straight motion.

Research on Motion Control of AUV with Hybrid Actuators

2013 ◽  
Vol 341-342 ◽  
pp. 906-912 ◽  
Author(s):  
Lei Zhang ◽  
Da Peng Jiang ◽  
Shu Ling Huang ◽  
Jin Xin Zhao
Keyword(s):  
Motion Control ◽  
High Speed ◽  
Autonomous Underwater Vehicle ◽  
Underwater Vehicle ◽  
Underwater Vehicles ◽  
Velocity Control ◽  
Yaw Control ◽  
Depth Control ◽  
System Vibration ◽  
The Stability

A switch function is presented to smooth control instructions and avoid system vibration during switch operating underwater vehicles with hybrid actuators. And a Modified S-plane Controller (MSC) is proposed by analyzing underwater vehicles dynamics and taking static force and coupling effects between the longitude velocity and other dimensions into account. Besides the advantages of S controller such as simple structure, MSC can solve the motion control of underwater vehicle at high speed which is difficult to control with S-plane controller. The stability of MSC is analyzed with Lyapunov function. Finally, MSC is applied to the motion control of an autonomous underwater vehicle controlled by rudders and thrusters. The feasibility of MSC is demonstrated by the results of velocity control, yaw control and depth control tests.

scholarly journals Robust Position Control of an Over-actuated Underwater Vehicle under Model Uncertainties and Ocean Current Effects Using Dynamic Sliding Mode Surface and Optimal Allocation Control

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 747
Author(s):  
Mai The Vu ◽  
Tat-Hien Le ◽  
Ha Le Nhu Ngoc Thanh ◽  
Tuan-Tu Huynh ◽  
Mien Van ◽  
...  
Keyword(s):  
Control System ◽  
Motion Control ◽  
Optimal Allocation ◽  
Position Control ◽  
Sliding Mode ◽  
Underwater Vehicle ◽  
Ocean Current ◽  
Model Uncertainties ◽  
Control Module ◽  
Dynamic Sliding Mode

Underwater vehicles (UVs) are subjected to various environmental disturbances due to ocean currents, propulsion systems, and un-modeled disturbances. In practice, it is very challenging to design a control system to maintain UVs stayed at the desired static position permanently under these conditions. Therefore, in this study, a nonlinear dynamics and robust positioning control of the over-actuated autonomous underwater vehicle (AUV) under the effects of ocean current and model uncertainties are presented. First, a motion equation of the over-actuated AUV under the effects of ocean current disturbances is established, and a trajectory generation of the over-actuated AUV heading angle is constructed based on the line of sight (LOS) algorithm. Second, a dynamic positioning (DP) control system based on motion control and an allocation control is proposed. For this, motion control of the over-actuated AUV based on the dynamic sliding mode control (DSMC) theory is adopted to improve the system robustness under the effects of the ocean current and model uncertainties. In addition, the stability of the system is proved based on Lyapunov criteria. Then, using the generalized forces generated from the motion control module, two different methods for optimal allocation control module: the least square (LS) method and quadratic programming (QP) method are developed to distribute a proper thrust to each thruster of the over-actuated AUV. Simulation studies are conducted to examine the effectiveness and robustness of the proposed DP controller. The results show that the proposed DP controller using the QP algorithm provides higher stability with smaller steady-state error and stronger robustness.

scholarly journals Improved Stability Criteria of Static Recurrent Neural Networks with a Time-Varying Delay

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Lei Ding ◽  
Hong-Bing Zeng ◽  
Wei Wang ◽  
Fei Yu
Keyword(s):  
Neural Networks ◽  
Recurrent Neural Networks ◽  
Linear Matrix ◽  
Time Varying ◽  
Time Varying Delay ◽  
Improved Stability ◽  
The Stability ◽  
Delay Dependent ◽  
Delay Dependent Stability ◽  
Varying Delay

This paper investigates the stability of static recurrent neural networks (SRNNs) with a time-varying delay. Based on the complete delay-decomposing approach and quadratic separation framework, a novel Lyapunov-Krasovskii functional is constructed. By employing a reciprocally convex technique to consider the relationship between the time-varying delay and its varying interval, some improved delay-dependent stability conditions are presented in terms of linear matrix inequalities (LMIs). Finally, a numerical example is provided to show the merits and the effectiveness of the proposed methods.

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