scholarly journals Design and development of anchoring positioning control system for riprap leveling ship

2021 ◽  
Vol 233 ◽  
pp. 04007
Author(s):  
Xiaotao Hua ◽  
Yan Liu ◽  
Haiyang Sun ◽  
Jianru Chen
Keyword(s):  
Control System ◽  
Equilibrium State ◽  
Degrees Of Freedom ◽  
Wind Wave ◽  
Control Method ◽  
Positioning Control ◽  
Six Degrees Of Freedom ◽  
Hydrodynamic Parameters ◽  
Convergence Control ◽  
Heading Angle

It is very important to level foundation bed by riprap in water and soil engineering. In this paper, a real-time feedback convergence control method is proposed to control the position and heading angle of the riprap leveling ship. The wind, wave, current and hydrodynamic parameters are obtained by empirical formula; the tension of four cables is calculated according to the balance equation of six degrees of freedom, and then the cable deformation is obtained. According to the deformation of the cable, the length of the cable in a certain equilibrium state can be obtained. The length of four cables can be lengthened or shortened by comparing the length of cables at two balanced positions. The length of cables can be controlled by winch to complete the anchoring and positioning control of leveling ship.

Balancing Control of a Mobile Manipulator with Two Wheels by an Acceleration-Based Disturbance Observer

2018 ◽  
Vol 15 (03) ◽  
pp. 1850005 ◽  
Author(s):  
Yeong-Geol Bae ◽  
Seul Jung
Keyword(s):  
Disturbance Observer ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Experimental Studies ◽  
Service Robot ◽  
Mobile Manipulator ◽  
Control Performance ◽  
Six Degrees Of Freedom ◽  
Inertia Model ◽  
Balancing Control

This paper presents the balancing control performance of a mobile manipulator built in the laboratory as a service robot called Korean robot worker (KOBOKER). The robot is designed and implemented with two wheels as a mobile base and two arms with six degrees-of-freedom each. Kinematics and dynamics of the robot are analyzed. For the balancing control performance, two wheels are controlled independently by the time-delayed control method based on the inertia model of the robot. The acceleration information obtained directly from the sensor is used for the modified disturbance observer structure called an acceleration-based disturbance observer (AbDOB). Experimental studies of the balancing control of the robot are conducted to compare the control performances by both a PID control method and an AbDOB.

Model Tests for Safe-Return-to-Port of a Damaged Ship in Waves

2015 ◽  
Author(s):  
Jeonghwa Seo ◽  
Cristobal Santiago Bravo ◽  
Shin Hyung Rhee
Keyword(s):  
Degrees Of Freedom ◽  
Feedback System ◽  
Model Tests ◽  
Measurement Unit ◽  
Test Model ◽  
Motion Response ◽  
Six Degrees Of Freedom ◽  
Heading Angle ◽  
Wave Conditions ◽  
Damaged Ship

A series of tests using a course-keeping model ship with an autopilot system were carried out in a towing tank for research on Safe-Return-to-Port (SRTP). The autopilot system controls the rudder angle and propeller revolution rate by a feedback system. The variation of the heading angle of the test model with different control parameters was investigated first, to ensure that the test model had sufficient course-keeping maneuverability in severe wave conditions. The wave conditions and propeller revolution rate were selected based on SRTP regulations. Tests were conducted in wave conditions corresponding to sea states 4 to 6. The six-degrees-of-freedom motion response of the test model was measured by a wireless inertial measurement unit and gyro sensors to achieve fully wireless model tests. The advance speed and motion response in various wave conditions were measured and analyzed to investigate the effects of flooding behavior in a damaged condition and of waves on the propulsion and maneuvering performance of the damaged ship model.

Heading control of a novel finless high-speed supercavitating vehicle with an internal oscillating pendulum

2020 ◽  
pp. 107754632094834
Author(s):  
Mojtaba Mirzaei ◽  
Hossein Taghvaei
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Sliding Mode ◽  
Six Degrees Of Freedom ◽  
Supercavitating Vehicles ◽  
Supercavitating Vehicle ◽  
High Speeds ◽  
Heading Control ◽  
Heading Angle ◽  
Control Surfaces

High-speed supercavitating vehicles are surrounded by a huge cavity of gas and only a small portion of the nose and the tail of the vehicle are in contact with the water which leads to a considerable reduction in skin friction drag and reaching very high speeds. High-speed supercavitating vehicles are usually controlled by the cavitator at the nose which controls the pitch and depth of the vehicle and the control surfaces or fins which control the roll and heading angle of the vehicle using the bank-to-turn maneuvering method. However, control surfaces have disadvantages such as the high drag force and ineffectiveness due to the supercavity. Therefore, the purpose of the present study is to eliminate the fins from high-speed supercavitating vehicles and propose a new bank-to-turn heading control of this novel finless high-speed supercavitating vehicle which is composed of the cavitator at the nose and an oscillating pendulum as the internal actuator. Sliding mode control as a robust method is used for the six-degrees-of-freedom model of this finless high-speed vehicle against exposed disturbances. Some design criteria for the design of the internal pendulum in this finless supercavitating vehicle are presented for the damping coefficient, pendulum mass, and radius.

Determination of Hydrodynamic Parameters for Remotely Operated Vehicles

2016 ◽  
Author(s):  
Ole A. Eidsvik ◽  
Ingrid Schjølberg
Keyword(s):  
Numerical Simulations ◽  
Degrees Of Freedom ◽  
Analytical Data ◽  
Relative Difference ◽  
Accurate Estimate ◽  
Six Degrees Of Freedom ◽  
Hydrodynamic Parameters ◽  
Planar Motion Mechanism ◽  
Rotational Degrees Of Freedom

In this paper the hydrodynamic parameters that characterize the behavior of a typical unmanned underwater vehicle are evaluated. A complete method for identifying these parameters is described. The method is developed to give a brief and accurate estimate of these parameters in all six degrees of freedom using basic properties of the vehicle such as dimensions, mass and shape. The method is based on both empirical and analytical results for typical reference geometries (ellipsoids, cubes, etc.). The method is developed to be applicable for a wide variety of UUV designs as these typically varies substantially. The method is then applied to a small observation class ROV. The results are first verified using an experimental method in which the full scale ROV is towed using a planar motion mechanism. An additional verification is performed with numerical simulations using Computational Fluid Dynamics and a radiation/diffraction program. The method shows promising results for both damping and added mass for the tested case. The translational degrees of freedom are more accurate than the rotational degrees of freedom which are expected as most empirical and analytical data are for translational degrees of freedom. The case study also reveals that the relative difference between the numerical simulations and the experimental results are similar to the relative difference between the proposed method and the experiment.

Development of active six-degrees-of-freedom microvibration control system using giant magnetostrictive actuators

2000 ◽  
Vol 9 (2) ◽  
pp. 175-185 ◽  
Author(s):  
Yoshiya Nakamura ◽  
Masanao Nakayama ◽  
Keiji Masuda ◽  
Kiyoshi Tanaka ◽  
Masashi Yasuda ◽  
...  
Keyword(s):  
Control System ◽  
Degrees Of Freedom ◽  
Six Degrees Of Freedom ◽  
Magnetostrictive Actuators

Design of Robust Nonlinear Optimal Controller for Underwater Vehicle to Move in Depth Channel Using Gradient Descent Method with Systematic Step Selection

2014 ◽  
Vol 704 ◽  
pp. 320-324
Author(s):  
Marzieh Ahmadi ◽  
Abolfazl Halvaei Niasar ◽  
Alireza Faraji ◽  
Hassan Moghbeli
Keyword(s):  
Gradient Descent ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Parametric Uncertainty ◽  
Underwater Vehicle ◽  
Descent Method ◽  
Optimal Controller ◽  
Gradient Descent Method ◽  
Six Degrees Of Freedom ◽  
Step Selection

This paper proposes the design of a robust nonlinear optimal controller to move the underwater vehicle in the depth channel using gradient descent method. A nonlinear model with six degrees of freedom (6-DOF) has been extracted for the underwater vehicle. To selection of the model and design of controller, conventional assumptions used for other controllers have not been considered and the developed controller can be implemented via at least assumptions. In presented control method, systematic step selection for solving of the algorithm has increased the rate of convergence significantly. The performances of the proposed robust controller for moving in depth channel with considering of parametric uncertainty for the model have been confirmed via some simulations. The results show the desirable performance of developed controller.

Nonlinear system controllability analysis and autopilot design for bank-to-turn aircraft with two flaps

2018 ◽  
Vol 233 (5) ◽  
pp. 1772-1783 ◽  
Author(s):  
Jinlu Dong ◽  
Di Zhou ◽  
Chuntao Shao ◽  
Shikai Wu
Keyword(s):  
Numerical Simulation ◽  
Control System ◽  
Nonlinear System ◽  
Feedback Linearization ◽  
Degrees Of Freedom ◽  
Lyapunov Stability Theory ◽  
Zero Dynamics ◽  
Controlled System ◽  
Linearization Technique ◽  
Six Degrees Of Freedom

In this study, the six-degrees-of-freedom flight motion of a tail-controlled bank-to-turn aircraft with two flaps is described as a nonlinear control system. The controllability of this flap-controlled system is analyzed based on nonlinear controllability theory and the system is proved to be weakly controllable. By choosing the angle-of-attack and roll angle as the outputs of this control system, the zero dynamics of the system are analyzed using Lyapunov stability theory, and are proved to be stable under some conditions given by an inequality. Then an autopilot is designed for this system using the feedback linearization technique. Results of the numerical simulation for this control system show the effectiveness of the controllability analysis and autopilot design.

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