Research On MWD Digital Gyroscope Driving And Pulser Servo Control

Gyro digital drive and pulser servo control are two important technologies for the measure while drilling(MWD)in petroleum drilling.The gyroscope is one of the most important sensors in the drilling measurement system.The pulser converts the sensor information to the mud pressure pulse,which can be measured and decoded by the ground system.Finally,the original sensor information can be obtained.The digital drive of the MWD gyroscope and the high speed servo control of the pulser are studied in this work.Besides,the influence of the different algorithms on the robustness of the two control systems is analyzed.Firstly,the structure and working principle of the power tuned gyroscope and the brushless direct current motor(BLDCM)are introduced,and then they are modeled.Secondly,the algorithms designed for two control systems were described,including the PID control algorithm,robust control algorithm and Z domain discrete design of the gyro drive system as well as the double closed loop PI control algorithm,fuzzy PI control algorithm of the BLDCM control system.Next,the hardware and software design principles of the gyroscope digital drive circuit and the pulser servo control circuit are introduced.Finally,the simulation model was built with MATLAB/SIMULINK.The simulation and test results show that the two systems can run well.The robust control algorithm of the gyroscopic digital drive system and the fuzzy PI control algorithm of the BLDCM system can effectively improve the robustness of the system.