Suppression of stick-slip in drillstrings: A control approach based on modeling error compensation

An approach for the robust suppression of stick-slip oscillations in oil drillstrings is presented. Two control configurations are derived: a cascade control scheme, where a favorable choice of virtual input control variables is demonstrated, and a decentralized control scheme, where two control inputs are manipulated. The control approach is based on modeling error compensation techniques to provide robustness against uncertain parameters and friction terms. Numerical simulations are provided to illustrate the control performance.