Research On Automatic Leveling System For Seabed Drilling

The capability of marine resources exploration and exploitation is an important symbol to measure the technical level of the National Oceanic, and the seabed drilling is one of the most important equipment to research geological structures, look for mineral resources, engineer geological investigation of the Continental Shelf and do other maritime infrastructure task. Therefore, enhancing national ocean technology level must need advanced seabed drilling rig. The seabed drilling rig working face inclination is one of the important factors that affect the seabed drill samples, and determine the drilling sampling completeness, the service life of rig and drilling tools, at the time, the safe use of rig.Based on the research and analysis of domestic and international seabed drilling rig leveling system and the working environment of the seabed rig. this paper researches the automatic leveling system key technology, analyzes the principle of rig leveling, establishes the mathematical model of the leveling of drilling rig, and puts forward a kind of simple but feasible four leg leveling mechanism,which contains "high","single" and "one" strategies, and it is based on the electro-hydraulic proportional control technology. Specific content as follows:Although the three supporting structure is widely used for the leveling system of seabed drilling, the paper puts forward four supporting structure with stronger anti interference and overturning ability, and adopts hydraulic driving mode.By fixed supporting, the legs move difficultly, and the force between the leg and working surface must increase, so the outriggers adopt scroll controllable support. By this way, the process of leveling can be is simplified as "rotation" twice, and we can directly calculate the leg extension, to achieve "leveling in one time", which means that according to the angle values, the system calculates each leg cylinder elongation and complete the system adjustment one time.This way can enhance the leveling efficiency. When the leg shrinks, outrigger maybe lead to the "soft leg" which is bad for the safety of seabed drilling.For avoiding this, the paper puts forward "the line to the high point" which means that in the leveling process, the highest point keeping intact, and the other legs elongate until it is flush to the highest point. To improve improve the precision the electro-hydraulic proportional control technology is applied to the leveling system. After Setting up model of the electro-hydraulic proportional control system, the paper deduces the system transfer function and list the characteristic equation. According to the HuErWei watts stability assessment method, we can determine that the electro-hydraulic proportional control technology used in the leveling system of the seabed drilling is stable, safety and reliable.According to the system of leveling principle and leveling method, the paper designs the system hardware including the system control circuit design and hydraulic system design. In the system control circuit, the paper designs the power module, signal acquisition module, central control unit, the electromagnetic valve drive module, the electro-hydraulic proportional valve control module and the communication module. Analysing the characteristics and the control need of each module, the appropriate components is selected and the circuit connection diagram is drew. According to the hydraulic system functions, the paper draws a schematic of the hydraulic system and determines the basic circuit of the hydraulic system. Analysing the system design requirements and conditions, the paper determines the system working pressure, and calculates the parameters to select the matched hydraulic components.On the basis of hardware design, the software system is designed to match the system work requirements. The software system needs to achieve the basic functions which includ leg pressure signal acquisition, signal acquisition, inclination of electromagnetic valve and proportional valve driver. The software main function constituted by basic functions with certain logic control includes the landing anti-overturning, the "virtual leg" control and the system leveling. When the system work, the signals which contains the inclination, the pressure, the landing conditions and the virtual leg condition should be sent to the computer to display and monitor, through the serial port.Finally, the paper carried out the system software and hardware combined test indoor. Analyzing the collected data, we can draw a conclusion that the leveling system design is comply with the design requirements, and has the important significance to guide the the actual application. The paper carries on the summary and puts forward a new prospect.