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.

A Novel Sliding Mode Motion Control for Parallel Mechanism of Virtual Axis Machine Tool

2011 ◽  
Vol 138-139 ◽  
pp. 523-528
Author(s):  
Guo Qin Gao ◽  
Hai Bin Zheng ◽  
Xue Mei Niu
Keyword(s):  
Control System ◽  
Sliding Mode Control ◽  
Machine Tool ◽  
Motion Control ◽  
Parallel Mechanism ◽  
Sliding Mode ◽  
External Disturbances ◽  
Mode Control ◽  
Dynamic Sliding Mode Control ◽  
Dynamic Sliding Mode

This paper addresses the motion control of the parallel mechanism of virtual axis machine tool, which has a complex system model, the nonlinear and strong coupling characteristics and has strong external disturbances in high-speed machining. To further enhance its motion control performances, a novel adaptive dynamic sliding mode control method is proposed. The designed control system stability is proved theoretically. By building a new switching function, the second-order dynamic sliding mode control algorithm is designed to reduce the chattering of the conventional sliding mode control effectively and overcome the adverse effects of the fast changing dynamics of the actuators. By introducing the adaptive control, unknown external disturbances can be estimated online, which can improve the ability of resisting strong disturbances and the control precision of virtual axis machine tool. The simulation results for the virtual axis machine tool show that the designed control system has the good performances in tracking and resisting strong disturbances and can achieve the high precision motion control of the parallel mechanism of virtual axis machine tool.

Dynamic sliding mode position control of induction motors based load torque compensation using adaptive state observer

2018 ◽  
Vol 37 (6) ◽  
pp. 2249-2262
Author(s):  
Ali Karami-Mollaee ◽  
Hamed Tirandaz ◽  
Oscar Barambones
Keyword(s):  
Position Control ◽  
Sliding Mode ◽  
State Observer ◽  
Practical Implementation ◽  
Load Torque ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Content Type ◽  
Adaptive State Observer ◽  
Dynamic Sliding Mode

Purpose The purpose of this paper is position control scheme for a servo induction motor (SIM) with uncertainty has been designed using a new observer issue and a dynamic sliding mode control (DSMC). Design/methodology/approach In DSMC, the chattering is removed due to the integrator (or a low-pass filter) which is placed before the input control of the plant. However, in DSMC, the augmented system has one dimension bigger than the actual system (if integrator is used) and then, the plant model should be completely known. To solve this problem in SIM, the use of a new adaptive state observer (ASO) is proposed. Findings The advantage of the proposed approach is to maintain the system controlled under the external load torque variations. Then, the load variations do not affect the motor positioning. Moreover, it is demonstrated that the observer error converges to zero based on the Lyapunov stability theory. Originality/value The knowledge of the upper bound for the system uncertainty is not necessary in an adaptive state observer, which is important in practical implementation. Simulation results are presented to demonstrate the performance of the proposed approach.

scholarly journals Adaptive Feedforward Control of a Pressure Compensated Differential Cylinder

2020 ◽  
Vol 10 (21) ◽  
pp. 7847
Author(s):  
Konrad Johan Jensen ◽  
Morten Kjeld Ebbesen ◽  
Michael Rygaard Hansen
Keyword(s):  
Control System ◽  
Root Mean Square ◽  
Motion Control ◽  
Experimental Verification ◽  
Feedforward Control ◽  
Position Error ◽  
Mean Square ◽  
Model Uncertainties ◽  
Feedforward Controller ◽  
Adaptive Feedforward

This paper presents the design, simulation and experimental verification of adaptive feedforward motion control for a hydraulic differential cylinder. The proposed solution is implemented on a hydraulic loader crane. Based on common adaptation methods, a typical electro-hydraulic motion control system has been extended with a novel adaptive feedforward controller that has two separate feedforward states, i.e, one for each direction of motion. Simulations show convergence of the feedforward states, as well as 23% reduction in root mean square (RMS) cylinder position error compared to a fixed gain feedforward controller. The experiments show an even more pronounced advantage of the proposed controller, with an 80% reduction in RMS cylinder position error, and that the separate feedforward states are able to adapt to model uncertainties in both directions of motion.

scholarly journals A Speed Control Method for Underwater Vehicle under Hydraulic Flexible Traction

2015 ◽  
Vol 2015 ◽  
pp. 1-16
Author(s):  
Yin Zhao ◽  
Ying-kai Xia ◽  
Ying Chen ◽  
Guo-Hua Xu
Keyword(s):  
Control System ◽  
Control Theory ◽  
Control Method ◽  
Sliding Mode ◽  
Variable Structure ◽  
Speed Control ◽  
Underwater Vehicle ◽  
Vehicle Speed ◽  
Sliding Mode Variable Structure ◽  
Traction System

Underwater vehicle speed control methodology method is the focus of research in this study. Driven by a hydraulic flexible traction system, the underwater vehicle advances steadily on underwater guide rails, simulating an underwater environment for the carried device. Considering the influence of steel rope viscoelasticity and the control system traction structure feature, a mathematical model of the underwater vehicle driven by hydraulic flexible traction system is established. A speed control strategy is then proposed based on the sliding mode variable structure of fuzzy reaching law, according to nonlinearity and external variable load of the vehicle speed control system. Sliding mode variable structure control theory for the nonlinear system allows an improved control effect for movements in “sliding mode” when compared with conventional control. The fuzzy control theory is also introduced, weakening output chattering caused by the sliding mode control switchover while producing high output stability. Matlab mathematical simulation and practical test verification indicate the speed control method as effective in obtaining accurate control results, thus inferring strong practical significance for engineering applications.

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.

Implementation of Intelligent Control System for Autonomous Underwater Vehicle

2014 ◽  
Vol 701-702 ◽  
pp. 704-710 ◽  
Author(s):  
Viacheslav Pshikhopov ◽  
Yuriy Chernukhin ◽  
Viktor Guzik ◽  
Mikhail Medvedev ◽  
Boris Gurenko ◽  
...  
Keyword(s):  
Control System ◽  
Motion Control ◽  
Intelligent Control ◽  
Autonomous Underwater Vehicle ◽  
Control Method ◽  
Underwater Vehicle ◽  
Intelligent Control System ◽  
Azov Sea ◽  
Complex Simulation ◽  
Point To Point

This paper introduces the implementation of intelligent motion control and planning for autonomous underwater vehicle (AUV). Previously developed control system features intelligent motion control and planning subsystem, based on artificial neural networks. It allows detecting and avoiding moving obstacles in front of the AUV. The motion control subsystem uses position-trajectory control method to position AUV, move from point to point and along given path with given speed. Control system was tested in the multi-module simulation complex. Simulation showed good results – AUV successfully achieved given goals avoiding collisions not only with static obstacles, but also with mobile ones. That allows using the proposed control system for the groups of vehicles. Besides simulation, control system was implemented in hardware. AUV prototype passed tests in Azov Sea and proved its efficiency.

Design of Single-Axis Control System Based on FM354

2014 ◽  
Vol 926-930 ◽  
pp. 1289-1292
Author(s):  
Cong Qiu ◽  
Wang Yong He ◽  
Bo Tian
Keyword(s):  
Control System ◽  
Motion Control ◽  
High Performance ◽  
Position Control ◽  
Dynamic Performance ◽  
Current Loop ◽  
Loop Control ◽  
Precise Position ◽  
Ac Servo System ◽  
Ac Servo

AC servo system has been widely used in many fields with its high performance and the fast development of intelligent control strategy. Targeted at the single-axis motion control applications in industrial automation, a kind of single-axis motion control system, based on FM354 controlled by S7-300 PLC, is designed. The system consists of three to the position, speed and current closed-loop control to achieve precise position control. The position loop is implemented by FM354. The speed loop and current loop are encapsulated in the servo driver. Through monitoring and comparing the dynamic performance with traditional systems, it can find out the bench runs smoothly and positioning accurately, perfectly meeting the technological and application requirements. It also can be applied to a variety of occasions and used for multi-axis extension.

Analysis of an Opto-Pneumatic Control System and Improvement of its Control Performance

1999 ◽  
Vol 11 (4) ◽  
pp. 251-257 ◽  
Author(s):  
Tetsuya Akagi ◽  
◽  
Shujiro Dohta ◽  
Hisashi Matsushita ◽  
Keyword(s):  
Control System ◽  
Position Control ◽  
Sliding Mode ◽  
Pneumatic Cylinder ◽  
Control Performance ◽  
Pneumatic Control ◽  
Servo Valve ◽  
Proposed Model ◽  
Control Scheme

This paper describes an analysis of an opto-pneumatic control system and an improvement of control performance of the system. The opto-pneumatic system consists of an optical servo valve, a pneumatic cylinder and a cart. First, we built an analytical model of the system considering a nonlinear friction where exists in sliding parts. And we confirmed the validity of the proposed model by comparing theoretical results with experimental results of the characteristics of optical servo valve and cart position control. Then, we applied a sliding mode control scheme compensating a steady-state disturbance to multi- position control and follow-up control of a cart. By computer simulation, we confirmed that the control performance of opto-pneumatic control system was improved by using this control scheme.

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