Research On Limit Load Control Technology Of Rotary Drilling Rig Basedon DTC

Rotary drilling rig is a construction machine for drilling, with big installed power, large output power, large output moment of torque, much axial pressure, automotive flexibility, high efficiency of construction and so on, widely used in the construction of infrastructure projects.The power system of the rotary drilling rig consists of a diesel engine and a variable displacement pump. Its working conditions are very complex, with changeable load. Large load will slow down or even turn off the engine, which seriously affected the stability and efficiency of rotary drilling rig construction, and will increase fuel consumption and reduce the service life of rotary drilling rig. This requires an effective power control method to adapt to changing workloads. To solve these problems, this paper will study on the rotary drilling rig limit load control technology.First of all, on the basis of analysis of the working data of the rotary drilling rig, the problem that the engine speed down because of overloading and the power efficiency is not high is studied in detail. The main reason is that the engine power and the pump power do not match. And then the working principle of the variable displacement pump is analyzed. The mathematical model of the variable displacement pump is established. This paper proposes a rotary drilling rig limit load control strategy based on direct torque control.Secondly, to improve the performance of the rotary drilling rig power systems, a fuzzy PID control algorithm is studied. The advantage of fuzzy PID control algorithm is discussed. A fuzzy PID controller is designed. The method to obtain the parameters of the fuzzy controller and its influence on control performance are analyzed.Thirdly, using the AMESim and MATLAB/Simulink, the simulation of the limit load control system is studied. By comparing the control efficiency of PID and fuzzy PID control method, it shows that fuzzy PID control strategy and algorithm has better control efficiency and is more feasible.Finally, the experimental research is conducted on the rotary drilling rig. Experiment contents include primary volume increased down and drilling experiment. The experimental results show that the fuzzy PID control method based on the torque sensor to make the drop speed value of the rotary drilling rig engine reduced by 40%, and the engine power utilization ratio increased by 14.5%. The control effect is superior to the traditional PID control method based on speed induction control. It verifies that the fuzzy PID control method based on the torque sensor control to realize the engine-variable pump power matching has a better effect.