Research On Pressure Control System Of Auto-drilling Based On Fuzzy Self-adaptive PID Theory

At present, PID control method is used widely in today's auto-drilling, the classical PID control has own merit, the principle is simple, easy to operate, robustness is strong, so it is widespread continuously. But, there is time lag, time-variable, the non-linear characteristic in auto-drilling, There are deformations, time lag and so on between steel wire, big hook and drill rod, change speed gear interior, and the accusation quantity (bit pressure) also influenced by the geological situation, the drill bit attrition situation, the drilling fluid and the water power parameter. So, sometimes, the PID control method can't express good control result.This article, first, I designed the control system 's hardware, software and HMI screen, software design used SIEMENS STEP 7software, configuration screen used Wincc flexible software.second, I synthesize the merits of classics PID control algorithm and the fuzzy algorithm, used the fuzzy auto-adapted PID controller to control the bit pressure,used fuzzy control rule to revised the PID parameters, The fuzzy control can imitate human's intelligence, mainly to solve these complex, non-linear, the uncertainty system's control problems. It is one kind of based on the fuzzy language variable's control method, relies on the actual operation experience, use fuzzy algorithm carries on the inference and the decision-making. We make the PID control mode to achieve the best control effect.Third, I make the simulation to auto-drilling system with the MATLAB software, the simulation result has indicated this control method's validity.