Synchronization Research Of Two Boom Cylinders Of Rotary Drilling Rig At The Decline Stage Of Luffing

Rotary drilling rig is an equipment of modern piling machinery used in pore-performing work of infrastructural project. Now, in the international market, the homemade rotary drilling rigs are confronted with increasing competition, which especially proposes more stringent requirements to the reliability and safety of the homemade large-tonnage rotary drilling rigs, while the synchronization performance of the two boom cylinders of rotary drilling rig at the decline stage of luffing has close impact on the stability of the crucial luffing movement and the safety of the complete machine. Therefore, taking a280kNm rotary drilling rig as a research object, the synchronization of the two boom cylinders at the decline stage of luffing was studied in this paper. The main contents are as follows:1. Development status and tendency of rotary drilling rig were summarized. Research status of boom luffing mechanism was elaborated. Main contents and research significance of the issue was put forward.2. The mathematical model of boom luffing mechanism was built to study the load change of the luffing cylinders. The virtual prototype of rotary drilling rig was established in ADAMS and the working condition of the decline stage of the boom luffing mechanism was simulated. Thus, the load-change curves of the boom luffing cylinders under two different mast postures were obtained, which laid a good foundation for the research of the synchronization of the two boom cylinders and its simulation and optimization.3. Working principle of the hydraulic system of boom luffing mechanism was analyzed and the mathematical model of its key component, the counterbalance valve, was set up. Combining the simulation results of mechanical system, the impacts that the damping holes of the control oil circuit, the pressure conductivity coefficients, the spring preloads and unbalance loading exert on the synchronization of the two boom cylinders were researched. Then, the methods of improving the synchronization of the two cylinders were proposed and the effects of the synthetic approach were studied.4. Considering the influence on the synchronization of the two boom cylinders exerted by luffing mechanism and its hydraulic system, the joint simulation model of the boom luffing system was established with AMESim and ADAMS to optimize the synchronization of the two boom cylinders. Comparing the effects of the adopted improving methods and their synthetic project, the optimization project used in this paper was proved to be effective.5. Experiments were done in a real rotary drilling rig before and after optimization. The results showed that the theoretical research and simulation analysis in this paper were correct.