| Rich marine oil resources attract global countries to explore and excavate, and to ensure marine operation safety and effectiveness is the essential condition of marine oil development. Heave compensation system as one of the main devices, its importance and generalized application make its technology and development improve constantly. But our country’s heave compensation system in marine operation is still mainly relied on foreign imports, not only the technology controlled by others, but also expensive, the time consumes and delays. Therefore, in order to promote the development ability of ocean engineering in our country, safeguard maritime rights and interests, developing the heave compensation device with independent property rights in our country is necessary and cannot wait.As the necessary auxiliary equipment for drilling platform, heave compensation device’s quality directly decides the performance of drilling quality. In this paper, winch active compensation device based on the principle of constant tension as the heave compensation design, with the core target of improving the effect of heave compensation, researches are done with the winch structure, control theory model, the upper computer software programming, and servo system design and so on.(1) A large amount of literature and data are accessed for the ocean drilling platform heave compensation device, the existing products’principle structure and dynamic form are summarized, and the shortage of all kinds of products in the practical application process are pointed out. The climate condition in our country’s Marine mining area is investigated, and the motion state of drilling system under the action of the waves is analyzed. Finally the overall design scheme of winch active heave compensator based on the principle of constant tension is proposed based on the above investigation and analysis, and the parameters of heave compensation system is determined.(2) Most of the existing heave compensation devices adopt the hydraulic power system, which have the problem of the equipment taking up a large space, and having a slow response speed. Aiming at these, this paper designs the electric servo winch for ocean drilling platform heave compensation system. The basic structure of winch is mainly composed of servo motor, reducer, electromagnetic clutch, drum, etc. Winch is driven by the servo motor, and through the speed reducer, the electromagnetic clutch transmit to drum, so as to realize the rotation of the drum; Drum assembly has a capacitor structure, servo motor, reducer and electromagnetic clutch are embedded within the winch drum, drum assembly is fixed on the base plate through the left and right support plate; Left of the drum assembly connects to the brake, left of brake’s output shaft connect to the hanging wheel speed chain, the output of the hanging wheel speed chain is the rope’s two-way screw; Winch drum rotates a circle, the rope device moves a wide line along with drum’s axial direction, when the rope device reach the edge of the winch drum, it has reverse movement, rope machine moves back and forth, thus achieve the goal of neat uniform rope.(3) The control process of heave compensation winch is:first of all, bit pressure is determined according to the requirement of stratum drilling, and then according to the bit pressure to determine the tension values of steel wire rope, which is as a control object of the system. System compares the real-time detection of tension value with the set value, and gets the deviation and the deviation change rate. Computer calculates by fuzzy PID control algorithm, the controlled quantity is input to the servo controller, servo controller converts the controlled quantity into corresponding voltage, which is input to the winch driven by servo motor, to control the servo winch’s steering, rotational speed and torque, in order to maintain constant of rope tension values, and provide bit pressure required for normal drilling.According to the control demand, the mathematical model of control system is established, and simulation analysis is done with the MATLAB software. The simulation results show that the, system overshoot volume decreases significantly with the fuzzy PID control, the control precision is higher and anti-interference ability is stronger. Therefore, fuzzy PID control not only can improve the control precision of the whole system, but also has a strong robustness for the system with obvious complexity and object modeling’s inaccuracy and all kinds of outside interference and other uncertainties lead to the unstable system.(4) According to the Marine environment, equipment parameters and function demand characteristics, with the laboratory winch model as the experiment object, built hardware system with NI industrial PC, PCIe6363 data acquisition card, NI7350 motion control card and other modulation circuit, write the Fuzzy PID control program based on LabVIEW platform and Fuzzy-PID toolkit, complete each function module’s basic motion control tasks.After set up, the winch heave compensation system is test on the wave simulator. The test results show that the winch moves smooth, and prototype structure meet the control demand. Servo motor can work accurately under the control program, and the error can meet the design requirements, tension detection program can detect the change of tension accurately and rapidly. The fuzzy PID control program can carry on the fast and accurate response to the input, which verifies the rationality of theoretical analysis. Each module in the system works properly, and achieves the intended target of the system.The innovation points in this paper are as follows:(1) The drill string heave compensation function is realized by way of constant tension winch, which reduces the space of heave compensation equipment, and improves the equipment’s response speed.(2) The fuzzy control algorithm is applied to time-varying, nonlinear drilling platform heave compensation system. It improves the system’s robustness, and enhances the control’s response speed and precision. |
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