Research On The Heave Compensation Control Approach Of Lift Equipment On Ship Deck

It is necessary to have the corresponding deep-sea marine engineering equipment as the basis.The ship deck lifting equipment is one of the core equipment of marine engineering,which is often used for lifting operations in the marine environment.Because of the influence of the wave,the ship will produce undulation,advance,drift,pitch,roll,yaw and its coupling motion,especially the heave sports meeting will bring great interference and safety hidden danger to the effective operation of the ship deck hoisting equipment.In order to improve this situation,it is necessary to add a heave compensator for effective wave heave compensation.In this paper,a compound linear motion heave compensation system is designed under the operating conditions of not more than four levels of sea conditions.The system works in parallel between active cylinder and passive cylinder,and the structure of four multipliers is adopted.The dynamic analysis and modeling of the system are carried out,and the results show that the amplitude margin and phase margin of the designed system can meet the design requirements based on the Byrd diagram of the system.Because the acquisition of ship displacement data depends on MRU sensor in practical engineering system,considering the time delay of MRU sensor,the effect of control system will become worse.Therefore,this paper uses the method based on spectrum analysis to predict the heave motion of ship in short time,and carries on the simulation verification.Considering that the signal from the MRU sensor will contain some system noise,the wavelet transform method is used to filter the data in this paper.The error rate of short-time prediction within 1 s is less than 3% by simulation,which can meet the engineering requirements.Considering that the compensation rate of the ordinary PID algorithm can not meet the design requirements,other more suitable algorithms should be chosen.Two control algorithms,predictive control and sliding mode control,are designed to solve the problem that the parameters of the system may change greatly in the process of operation.The predictive control algorithm and sliding mode control algorithm are analyzed in detail,and some shortcomings of each algorithm are improved.In addition,the compensation effect and robustness of the two algorithms are analyzed and compared in detail.The results show that if the system parameters are basically constant,the predictive control algorithm should be used,and the compensation rate is higher;if the system parameters change greatly,sliding mode control should be used,and its robustness is stronger.Based on the theoretical analysis and calculation mentioned above,the heave compensation test prototype is developed.The basic working principle of the prototypesystem is introduced,the similarity of the prototype system is explained,and the main parameters of the prototype system are given.The installation and debugging of the heave compensation test prototype are completed,and the preliminary experiments are carried out.It provides a reference for the development of engineering prototype of heave compensation system.