Research and experimental analysis of stick-slip control method based on robust nonlinear

In the process of oil drilling, stick-slip vibration will cause the performance of drilling tools to decrease, and the service life will decrease rapidly, which will reduce the drilling efficiency and increase the drilling cost. To inhibit the stick – slip vibration that occurred during the downhole drilling process, a drill string torsional vibration system considering the torsional vibration tool has been proposed on the basis of solving the stick-slip problem by torsional vibration tool, and the torsional equation of drill string is obtained. Two sliding mode control and two PID control viscosity reduction methods are proposed. Combined with the tool function and theoretical equations, the viscosity reduction effects of the four control methods were analyzed and compared. The analysis shows that the four sliding mode control methods can effectively control the stick-slip vibration of the drill string, sliding mode control mode U2, and PID control mode U4 have better overall control performance and sliding mode control mode U2 has stronger robustness. PID control mode U4 has the best control performance. The stick-slip control method is beneficial to improve the stability and reliability of the drill string system.