Active Control of Stick-Slip Torsional Vibrations of Drill-Strings using Non-Switching Sliding Mode Controller

Torsional vibrations of drill-strings are actively controlled using a non-switching sliding mode strategy. The controller is intended also to reject the effect interaction between drill-bit and rock formation which induces non-linear stick-slip friction torque while tracking desirable constant angular velocity drill-string. In order demonstrate merits proposed control algorithm, it integrated with simple two degrees-of-freedom model drill-string considered as benchmark for studying induced torsional vibrations. Details development individual components making up entire action (SMC) presented. These aim at rejecting external disturbance reference Such established Lyapunov stability criterion. Numerical examples presented effectiveness SMC influenced by weight-on-bit (WOB), rotational speed, main parameters controller. sensitivity (SSS) maps developed illustrate performance characteristics active system different operating conditions important design SMC. approach envisioned present an invaluable practical means effectively mitigating undesirable effects frictional disturbances on drill-stings.