Research of constant WOB auto-drilling technology on AC frequency conversion rig

Due to characteristics of the traditional drilling way´s shortages, as well as the complexity and difficult mathematical model of the drilling process, etc, this paper briefly analyses the principle of auto-drilling system on AC frequency conversion and the relationship among all factors of affecting auto-drilling and puts forward a technology that combines the HSIC(Human-Simulated Intelligent Control) with constant WOB(Weight On Bit) auto-drilling technology on AC frequency conversion. Through the judgement of drilling pressure trend, based on human-simulated intelligent integral algorithm, application of PID control realizes the control of the rig´s speed. The algorithm does not need accurate mathematical model, can learn to fix control parameters in real time by itself. Test shows that the control system has good performance and ensures constant WOB and stable speed in auto-drilling and control algorithm can also be used in other auto-drilling systems.