Adaptive control of torsional oscillations in drill strings using a continuous-discrete extended Kalman filter

An indirect adaptive control strategy is developed to deal with self-excited torsional oscillations in drilling rig setups caused by friction during cutting action of the drill bit. The main contribution is the use of an online parameter estimator i.e. a state augmented continuous-discrete extended Kalman filter which is used to estimate parameters of the plant and adaptively update a robust backstepping controller in closed loop. The control strategy is simulated using parameters matching a real drill rig.