Research Of Motion Resolving And Filtering Algorithm Of A Ship's Three-freedom Motion Simulation Platform Based On LabVIEW

A lot of disturbances of ocean environment like sea wave, sea wind, ocean current and etc act on ship, leading to various wave-induced motions, while sails in the ocean. There are four basic ways to study the motions: simulation platform, ship model test, prototype test and theory analysis which are all unique in its way to deal with problems but related to each other in some degree.A three freedoms motion simulation platform for ship can be driven by either ship motion data (model or prototype) or the result of numerical modeling. Corresponding sensors are needed in the simulation of deck motion which includes pitch, roll and heave. Considering the measurement of the heave motion and the requirement of being coupled in all the three freedoms, angular rate gyro or vertical accelerometer which is both unidirectional can't acquire the true information of the platform motion. So the widely applied strap-down measurement system is adopted here to acquire the measurement information of the ship motion which is then used to calculate the time history of all three freedoms in a real-time and on-line way by using motion resolving software which after filtration is at last supplied to prediction computer to proceed the study of prediction algorithm.This paper first studies the measurement method and the motion resolving method of the strap-down measurement system and presents the contrast curve of resolving output signal and platform driven signal. Secondly, it analyzes the ship motion and gets the mathematical model of ship motion which is used as the base of Kalman filter. Then it studies the filter algorithm of measurement signal, uses Kalman and adaptive Kalman algorithm and presents the effect curve of the two filter algorithm. At last, this paper shows the procedure of collecting data of the...