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Paper details
Number 2 - June 2019
Volume 29 - 2019
A new efficient adaptive control of torsional vibrations induced by switched nonlinear disturbances
Maciej Wasilewski, Dominik Pisarski, Robert Konowrocki, Czesław I. Bajer
Abstract
Torsional vibrations induced in drilling systems are detrimental to the condition of the machine and to the effectiveness
of the engineering process. The cause of vibrations is a nonlinear and unknown friction between a drill string and the
environment, containing jumps in its characteristics. Nonlinear behaviour of the friction coefficient results in self-excited
vibration and causes undesirable stick-slip oscillations. The aim of this paper is to present a novel adaptive technique of
controlling vibrating systems. The scheme is based on the linear quadratic regulator and uses direct measurements of the
friction torque to synthesize its linear dynamic approximation. This approach allows generating a control law that takes
into account the impact of the friction on the system dynamics and optimally steers the system to the desired trajectory. The
controller’s performance is examined via numerical simulations of the stabilization of the drilling system. The proposed
solution outperforms the comparative LQG regulator in terms of the minimization of the assumed cost functional and the
overall stability of the control system under the nonlinear disturbance.
Keywords
vibration control, adaptive control, linear-quadratic-regulator, drilling control