Research On The Active Heave Compensation Control System Of Marine Crane

The ship lifting equipment with active heave compensation function can compensate the load's heave motion happening with the lifting mother ship caused by the fluctuation,and improve the working safety and efficiency of the deep-sea operations. Generally, the active heave compensation system is composed of four parts: the ship's heave motion detection system, the control system, the hydraulic drive system and the mechanical execution mechanism. The detection of the ship's heave motion is the precondition of the whole compensation system; the control system is the commands-maker; the hydraulic drive system and mechanical actuator are controlled to execute the control commands. The four modules coordinate with each other and work together to complete the compensation. Because the active heave compensation equipment is very important to the deep-sea operations, so it is very significant to carry out the research on the active heave compensation system.This thesis is based on the project—the development of active heave compensation system for deep-sea crane of Wuhan Marine Machinery Co, Ltd. According to the requirements of the project, the main research contents includes the following aspects:1 The detection of the mother ship's heave motion: Based on the full study of ship motion detection methods and ship motion characteristics, a real time detection scheme for the heave motion of the mother ship is designed. The main idea is: firstly, the acceleration and angular velocity of the ship's gravity center are parent measured by acceleration sensors and angular velocity sensors, after the processing, the ship's heave velocity and heave position are obtained by position and coordinate conversion.2 Mathematical model of heavy equipment is established: In this paper, taking the secondary regulation hydrostatic drive system as the drive means, respectively, starting from two aspects conducted to establish its mathematical model. First, from the standpoint of the analysis of the mechanism, based on the mathematical model of its various sub-components and the reasonable assumption, the whole mathematical model of the system was established .what's more, the follow-up controller's designment was based on this model.Second, based on the principles of system identification, the experimental program to get the system's model by using system identification methods was designed.3 The control system design: In light of the system time-delay, respectively, the control system was researched and designed based on the classical PID control and generalized predictive control; and then introduced a extremely short-term forecasting technology to solve the problem that the control system's compensation always lag behinds the mother ship's heave motion, making the real-time compensation become possible.4 Based on the Matlab/Simulink software platform, the active heave compensation control system simulation model was established and then carried on the simulation test on required working condition to get the performance experiment of the active heave compensation system.