Suppression of drill-string stick–slip vibration by sliding mode control: Numerical and experimental studies

Abstract

We investigate experimentally and numerically suppression of drill-string torsional vibration while drilling by using a sliding mode control. The experiments are conducted on the novel experimental drill-string dynamics rig developed at the University of Aberdeen (Wiercigroch, M., 2010, Modelling and Analysis of BHA and Drill-string Vibrations) and using commercial Polycrystalline Diamond Compact (PDC) drill-bits and rock-samples. A mathematical model of the experimental setup, which takes into account the dynamics of the drill-string and the driving motor, is constructed. Physical parameters of the experimental rig are identified in order to calibrate the mathematical model and consequently to ensure robust predictions and a close agreement between experimental and numerical results for stick–slip vibration is shown. Then, a sliding mode control method is employed to suppress stick–slip vibration. A special attention is paid to prove the Lyapunov stability of the controller in presence of model parameter uncertainties by defining a robust Lyapunov function. Again experimental and numerical results for the control cases are in a close agreement. Stick–slip vibration is eliminated and a significant reduction in vibration amplitude has been observed when using the sliding controller.

Parametric analysis of a sliding-mode controller to suppress drill-string stick-slip vibration

“…The numerically simulated, parametric analysis results of the open-loop drill-string under changes in WOB, top torque and stiffness are presented in the next section. This is followed by a similar parametric analysis of the drill-string controlled by the sliding-mode controller reported in [10]. Both these sections report analysis without considering the inherent actuator delay encountered in the experimental rig.…”

“…As a result, controllers for drilling systems that are capable of maintaining drill-string rotation at a constant angular velocity and the mitigation of torsional (stick-slip) vibration are of huge interest. Due to their simplicity, 1 or 2-DOF pendulum-type models are ideal for controller design [10].…”

“…As such, they are some of the most popular control schemes found in literature to address this particular problem, [36,37]. A recently proposed sliding-mode control scheme has shown to have effectively eliminated stick-slip vibration both in theory, [38] and in practice, [10]. It should be noted that all these control designs deliver improved stickslip suppression in the absence of inherent system delay.…”

“…In this paper, a recently proposed and experimentally validated sliding-mode controller [10], is used as a candidate to demonstrate the insights offered by the full parametric robustness analysis. The paper is organized as follows: next section describes the drillstring rig that was employed to conduct the supporting experiments included in this paper.…”

An inverse problem via cross-entropy method for calibration of a drill string torsional dynamic model

“…The global search capabilities and efficiency of the method are verified through the solution of an inverse problem that seeks to identify parameter values on the torsional dynamics of a validated experimental set-up (Cayres, 2018;Cayres et al, 2019). For the torsional mode vibration, a common subject is the extreme condition called stick-slip, wherein the drill-bit comes to a sudden stop but the top keeps in dynamic regimestoring energy -until the tip overcomes the rock resistance (Ritto, 2010;Vaziri et al, 2018). This phenomenon is present on the data and simulation of this work, modeled via dry friction.…”