Research On Floating Drilling Platform Heave Motion Simulator And Its Control System

When operating,floating drilling platform will do heave motion due to the influence of the waves,and this will result in the ups and downs of bits?crane hooks etc,making drilling pressure change and influencing the installation of subsea devices,affecting the operation on the platform.In the big sea condition,it can make bits and hooks separate from the devices,bring hidden safe troubles.So,to ensure normal operation in the big sea condition,developing and study for heave compensation system are of significance.Based on Six Degrees Of Freedom Platform and electric cylinder,the heave motion simulation device of computer control system are also respectively showed in this paper.This paper carries out a study on platform heave motion and thus provide theoretical base and practical value for future study on heave compensation system.Firstly,based on the Six Degrees Of Freedom Platform,the heave motion simulation system is established in the paper.And also,it has been analyzed and studied for the six-degree-of-freedom attitude of the drilling platform under the action of the waves.Based on the actual device,the open-loop control system and the closed-loop control system are designed and human machine interface is developed by C#.This paper shows the closed-loop real-time control system for heave motion simulation system based on the Six Degrees Of Freedom Platform.Secondly,in order to simulate the heave motion better,this paper builds up the heave motion simulation system based on the servo electric cylinder platform.According to the control requirements,the corresponding control mode is selected and the hardware system is configured and connected.Based on the P-M spectrum,the long wave is simulated and the mathematical model of the long wave is obtained.In view of STEP7 can only achieve a simple PID control,and is not conducive to the realization of complex wave model,so based on the PPI protocol,this paper achieve communication between the MATLAB and PLC.Respectively,open-loop system,closed-loop system are designed and implemented.In order to improve the real-time and control accuracy of the control system,a closed-loop control strategy based on feedforward-feedback is proposed and implemented on the actual device.Finally,the acceleration of the motorized cylinder simulation platform is measured by the attitude sensor MTi-300,and the acceleration data of the platform motion under open loop and closed loop control are preprocessed based on the digital average filtering algorithm,which further validates the realization of the system closed-loop real-time control.And the acceleration curve under closed-loop real-time control is carried out by sliding weighted average filtering and frequency domain low-pass filtering.Through comparison and analysis,the paper shows that the frequency filtering has better filtering effect than time domain filtering.