Parameter Adaptive Optimization Of Ship Antiroll Gyro Considering Random Sea Conditions

During voyages,the ships need an antiroll system to resist the wind and waves,so that it can be stable operation.Also,the crew's comfort would be higher.Compared with antiroll fin and antiroll water tank,as a new antiroll technology,the antiroll gyro is easy to install and use,small in size,low in energy consumption,and can produce an excellent anti-rolling effect from zero to any speed range.And the antiroll gyro has strong competitiveness in all kinds of small ship market.The existing researches are limited to improving the gyro's structure or verifying the effectiveness of different control methods,without constraining the gyros from the practical applications such as the allowable installation space in the cabin,the ship's power system and the damper and so on.Also,the existing researches ignore the problem of mutual restriction between the parameters of gyros.Besides,the current research on the control law simply considers the wave disturbance as the sine wave,and the simulation results are too ideal.Therefore,starting with the dynamic model of antiroll gyro,this paper analyzes the influence of gyro's parameters on the antiroll effect and optimizes the parameters of the antiroll gyroscope.What's more,considering the change of sea condition,this paper develops an adaptive design optimization strategy based on the enhanced genetic algorithm,so that the antiroll gyro can seek the optimal motion parameters according to the different sea conditions.The main research contents are as follows:Firstly,based on the long-peak wave model,the random wave mathematical model is established in this paper,and then the stress of the ship in the wave is analyzed.Based on the moment balance principle,the rolling motion of vessels under wave disturbance is modelled mathematically,which lays a foundation for the subsequent establishment of the joint dynamic model of ship antiroll gyro.Secondly,based on the mathematical model of random wave and the mathematical model of rolling motion of ship under wave disturbance,the dynamics model of antiroll gyro is built according to the coordinate transformation and moment of momentum theorem.Then the joint dynamical model of the ship-reduced gyroscope was established by combining the dynamics model of antiroll gyro with the mathematical model of random waves and ships.Thirdly,this paper takes a public service vessel with 594 t displacement and its supporting rotary antiroll gyro as the research object.Then analyzes the influence of theantiroll gyro's component parameters on the anti-rolling effect.The objective function is established with the aim of the highest roll reduction rate and the lowest rotor mass,and the two algorithms of pattern search and bacterial foraging are adopted to optimize its parameters.The optimized antiroll gyro has lower energy consumption,less material consumption and higher roll reduction rate.Finally,considering the changing sea conditions,this paper analyzes the influence of different shiploads,wave heights and average wave period on the anti-rolling effect.Based on the enhanced genetic algorithm,the self-adaptive optimization design of rotary antiroll gyro is carried out,and the effectiveness of the self-adaptive optimization is verified by Matlab simulation analysis.