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As far as the Air Cushion Vehicle (ACV) movement is concerned, established the nonlinear motion equations of the course and propose a sliding backstepping control algorithm base on the perturbation observer, according to the idea of backstepping recursive design, a robust variable-structure control system is used in each step to stabilize the control system what is unnecessary to adopt adaptive adjustment...
Sensors are important components of the dynamic positioning system, take compass for instance, which measures the course of a ship. Based on the Finite Impulse Response (FIR) filter, a simple and efficient sensor fault diagnosis scheme was proposed to improve the ability for judging whether sensor is out work or not. This method improved the capability of diagnosing when and what faults occur by using...
FPSO (Floating Production Storage and Offloading) is an important tool for the exploitation of marine resources currently. In order to improve the safe working performance of FPSO, especially in the complex sea environments, an improved Active Disturbance Rejection Controller (ADRC) was designed to achieve higher control accuracy. This kind of ADRC is the core controller with thruster mooring system...
A terminal sliding mode (TSM) control system with radial basis function (RBF) neural network, which is designed for enhancing the maneuverability and realizing the course control accurately of air cushion vehicle is proposed in the paper. An advanced TSM is utilized to drive the system to converge in a fast period of time, and attenuate the air cushion vehicle uncertainties and external disturbances...
With external disturbances, an robust synchronization control approach is present. Then the robust synchronization control system comprises a disturbances observer and an controller. The disturbances observer is used to estimating the disturbances. And the errors of vessels are introduced to the controller. Meanwhile, the stability of the disturbances observer and the controller are proved by the...
In this paper, an adaptive synchronization control approach is presented to control multiple fully actuated vessels along desired trajectory. And the communication network among these vessels is directed strongly connected but not necessarily balanced. Meanwhile, the control strategy is to synchronize each vessel with others in position and velocity. In addition, the proposed decentralized synchronization...
Optimal backstepping controller was designed to solve the variable parameterized tracking problem of a class of SISO nonlinear system in strict feedback form. Parameterized path following problem consists of path following and speed assignment tasks. In the path following task, local performance index function was given for the linear part of system. Then nonlinear recursive backstepping procedure...
In order to solve the problem of dynamic positioning ships when they lose the GPS signals during their operations, and cause drifting away from their setting points due to the deviant operation of the dynamic positioning system, this paper had designed a nonlinear filter which can use the history data of the ship to make real time estimating of the ship's position. This enable the ship maintains its...
The main difficulty in the control of underactuated mechanical system is that the system has more degrees of outputs to be controlled than the number of independent inputs. For the general ships, there are only main thrusters and rudder equipped with the ship. The problem of using the available control force to control the three degrees motion of ship can be classified into a kind of underactuated...
For burying cable ploughs need to follow a certain path, big ploughs are towed by surface vessels with powerful propulsion systems, modeling is rather important. Firstly, based on Colomb's passive earth pressure theory, the analysis of effects of pore water, cavitation limit and grain crushing limit are carried out. Secondly, the mathematical model considering the force acting on the plough from the...
A nonlinear estimate filter was designed for a dynamic positioning system. The global exponential stability of estimate filter was proven using Lyapunov methods. The main advantage of the nonlinear design to Kalman filter is that the kinematics equations of motion need not be linearized. The proposed estimate filter includes an estimation of both the low-frequency position and velocity of the ship...
Dynamic positioning (DP) systems for vessels are suffered from the environmental disturbances during its position keeping and offshore operation process. Because of the strong nonlinearity and uncertainty, there exist some difficulties in the design of DP controller. This paper proposes a nonlinear controller based on the active disturbance rejection control (ADRC) technique. The controller uses a...
The characteristics of the air cushion vehicle (ACV) show that the ACV is easy to be Broaching-to (the craft suddenly and unintentionally thrown or cause to turn, broadside to its original direction of motion). If the turning-rate is not to be controlled during ACV in the course keeping, the turning-rate and slide-angle will reach the warning or danger value that maybe led the ACV to be broaching-to...
A cascade control structure was designed for the path keeping based on the nonlinear motion model. The backstepping control is researched for the inner loop and the fuzzy control is introduced to the primary loop. The real time simulation results show that the controllers own high performance and follow the path very accurate in high speed under the wind disturbance.
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