Research On The Method Of Shipping Track Control Based On Ethernet

With the continuous development of shipping business, the density of navigation increases largely, the cannel and port becomes very narrow, and thus the safety of navigation and economy requirements are also constantly improving on the control precision of track and heading increasingly high demands; The current ship control system mainly contains the heading control and indirect tracking control, and their control performance and structure have yet to be further improved. Network Control System is a new control system theory with the rapid development of control technology, network technology and computer technology for the past ten years, which is used widely in terms of commercial and office as a successful network technology. Because of its high communication speed, technical resource-rich, low cost, so that the technology have been more and more applied to industrial control, and ship automation system is moving towards digital, network-oriented direction. This task is to build the ship in three degrees of freedom model, based on the consideration of the impact of environmental interference, and to study Ethernet-based ship tracking control method preliminary.This thesis used MMG (Maneuvering Mathematical Model Group) modeling idea to establish three degrees of freedom mathematical model of the ship, including the mathematical model of wind, waves and ocean currents. Then the advantages and disadvantages of the traditional PID were analyzed, and on this basis, use a nonlinear tracking differentiator (TD I) to arrange on the input signal to obtain a reasonable transition process and the differential signal, while use another nonlinear tracking Differential device (TDⅡ) to recover and get their feedback signal output differential signal, and then nonlinear combinations were used to deal with the error signal, error integral and error derivative signals, which is a better solution of the contradiction between fast and overshoot, and add feed-forward control because of the disadvantage of slow response when using close-loop controller in the delay system and non-minimum phase system, resulting in tracking control signals. Combination of the above four parts of this paper is the nonlinear PID controller. In the strategy on turning track passage, sets the distance of the ship and the turning point, which when the ship reaches, the track-keeping controller make ship into next route segment.Secondly, on the basis of bringing the concept of network control system, the Ethernet's random delay characteristic. Then describes the designed Ethernet-based ship control system simulation theory, introduce the TCP/IP protocol, analyze the client/server(C/S) communication model and communication theory, and propose the method of testing the average delay time.Finally, the simulation of ship tracking control system based on Ethernet was completed in a real LAN, because of the lack of network environment model. The simulation results show that the nonlinear PID controller in this article can make the ship keep tracking fast, and reach the control demand.