Study On Modeling And Control Of Two Degree Of Freedom Ship Simulation Platform Based On Virtual Prototype Technology

In the motion process of ship,the primary influences of ship motion are roll motion and pitch motion.The simulation and control of ship motion are very important issues.Based on virtual prototyping technology,a two degree of freedom platform is designed to simulate the ship rolling and pitching in actual sea conditions.This platform provides a basis for the establishment of the physical platform and the test of real ship to shorten the development cycle and reduce the cost.Sea wave is the main cause of ship rolling and pitching.This is the reason why the establishment of wave model become a top priority.Long-crested wave can be modeled by spectral analysis.Based on the analysis of ship motion,the simulation model of ship motion differential equation and wave inclination are established.In the ship motion model,the input is wave inclinaton and the output is the angel of ship rolling and pitcing.The two degree of freedom platform is established based on the ship rolling and pitching in actual sea conditions. In order to build a platform which can move as a real ship,the rational design of geometric models,connections,constraints and drivers is needed.The simulation test show that the movement performance of platform is good.The virtual prototype hydraulic is established to drive the simulation platforni.The ship rolling and pitching can be simulated by the stretch of drive shaft.Lastly,PID controller and fuzzy controller are designed and the control system simulation is implied by combining ADAMS and Matlab.Through the inverse solution computation in ADAMS,the input of ship motion attitude is transformed into the stretch of drive shaft to control the motion of ship platform and obtain the desired ship roll motion and pitch motion.The results of simulation show that the design of platform is reasonable, the simulation of ship rolling and pitching can be achieved without interference between the various agencies and the fuzzy controller is better than the PID controller.