Research On The Control Technology Of Ship Rotation Around Specified Point

The motion of ships rotating around the specified point is included into the ship dynamic positioning movement. It is defined as to control the additional thrusters equipped on the ship to compensate the extern disturbances of sea wind and current to make the ship move along the signified route.This paper targets the already-built vessel movement equations.Author applying the dividing model-building manners , under the reasonable purposed conditions,into the building and reasoning of outside disturbance environment, propelling machines, measuring instrument etc.According to the classified specified points and diameters ,the contents researched by author are divided into five cases below:Case 1 :rotating around the point out of ship body;Case 2: rotating around the point of ship' center;Case 3: rotating around the point of ship'right or left side center;Case 4: rotating around the point of ship'rear center;Case 5: rotating around the poit of ship'center,The paper discusses and analyzes each movement equation and based on which lists out the input variable of controller.Through the controlling way of each PID or fuzzy controller working to each thruster which keeps the anticipated movements of ship, the simulations show that.under the condition of disturbance of wind and current,each way of controlling ensures that the ship turns around the specified point with the given diameter and rotating rate within the precision.This paper is just first-time study on the relevant areas of ship'movement by the author,It would pave for the further or more profound research on this themes.