scholarly journals Mitigation of Torsional Vibrations in Drilling Systems using Adaptive Nonlinear Control System

2020 ◽  
Vol 9 (4) ◽  
pp. 3317-3321
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
String Model ◽  
Stick Slip ◽  
Rock Interaction ◽  
Performance Specifications ◽  
Level Model ◽  
Multi Level ◽  
The Stability ◽  
Level Training

The reason for this work is to plan a robust yield feedback control way to deal with dispense with torque stick-slip vibrations in boring frameworks. Current industry controllers generally neglect to dispose of stick-slip vibrations, particularly when different torque flex modes assume a job in maniacal assault. In terms of build controller production, a real trainingstring system performs a multi-level model work such as torque mechanics. The proposed controller design is artfully distorted at optimizing the stability with respect to the uncertainty of the nonlinear bit-rock interaction. Based on heroes and intentions. Besides, a closed loop strength examination of the nonlinear preparing string model is displayed. This controller structure system offers a few points of interest contrasted with existing controllers. To begin with, just surface estimations are utilized, barring the requirement for entire estimations underneath it. Second, multi-level training-string dynamics are effectively handled in ways to access state-training controllers. Third, stability is explicitly provided with respect to bit-rock contact uncertainty and closed-loop performance specifications include controller design. The results of the study report confirm that stick-slip vibrations are actually eliminated in realistic drilling scenarios using a controller designed to achieve this state-ofcontrol control.

A Semi-Analytical Study of Stick-Slip Oscillations in Drilling Systems

2010 ◽  
Vol 6 (2) ◽  
Author(s):  
B. Besselink ◽  
N. van de Wouw ◽  
H. Nijmeijer
Keyword(s):  
Dynamic Analysis ◽  
Limit Cycle ◽  
Analytical Approach ◽  
String Model ◽  
Drill String ◽  
Axial Stiffness ◽  
Torsional Vibrations ◽  
Stick Slip ◽  
Rock Interaction ◽  
Stiffness And Damping

Rotary drilling systems are known to exhibit torsional stick-slip vibrations, which decrease drilling efficiency and accelerate the wear of drag bits. The mechanisms leading to these torsional vibrations are analyzed using a model that includes both axial and torsional drill string dynamics, which are coupled via a rate-independent bit-rock interaction law. Earlier work following this approach featured a model that lacked two essential aspects, namely, the axial flexibility of the drill string and dissipation due to friction along the bottom hole assembly. In the current paper, axial stiffness and damping are included, and a more realistic model is obtained. In the dynamic analysis of the drill string model, the separation in time scales between the fast axial dynamics and slow torsional dynamics is exploited. Therefore, the fast axial dynamics, which exhibits a stick-slip limit cycle, is analyzed individually. In the dynamic analysis of a drill string model without axial stiffness and damping, an analytical approach can be taken to obtain an approximation of this limit cycle. Due to the additional complexity of the model caused by the inclusion of axial stiffness and damping, this approach cannot be pursued in this work. Therefore, a semi-analytical approach is developed to calculate the exact axial limit cycle. In this approach, parametrized parts of the axial limit cycle are computed analytically. In order to connect these parts, numerical optimization is used to find the unknown parameters. This semi-analytical approach allows for a fast and accurate computation of the axial limit cycles, leading to insight in the phenomena leading to torsional vibrations. The effect of the (fast) axial limit cycle on the (relatively slow) torsional dynamics is driven by the bit-rock interaction and can thus be obtained by averaging the cutting and wearflat forces acting on the drill bit over one axial limit cycle. Using these results, it is shown that the cutting forces generate an apparent velocity-weakening effect in the torsional dynamics, whereas the wearflat forces yield a velocity-strengthening effect. For a realistic bit geometry, the velocity-weakening effect is dominant, leading to the onset of torsional vibrations.

scholarly journals Stick-slip and Torsional Friction Factors in Inclined Wellbores

2018 ◽  
Vol 148 ◽  
pp. 16002 ◽  
Author(s):  
Ulf Jakob F. Aarsnes ◽  
Roman J. Shor
Keyword(s):  
High Frequency ◽  
String Model ◽  
Drill String ◽  
Distributed Model ◽  
Dynamic Friction ◽  
Stick Slip ◽  
Rock Interaction ◽  
Interaction Field ◽  
Friction Factors ◽  
Start Ups

Stick slip is usually considered a phenomenon of bit-rock interaction, but is also often observed in the field with the bit off bottom. In this paper we present a distributed model of a drill string with an along-string Coulomb stiction to investigate the effect of borehole inclination and borehole friction on the incidence of stick-slip. This model is validated with high frequency surface and downhole data and then used to estimate static and dynamic friction. A derivation of the torsional drill string model is shown and includes the along-string Coulomb stiction of the borehole acting on the string and the ‘velocity weakening’ between static and dynamic friction. The relative effects of these two frictions is investigated and the resulting drillstring behavior is presented. To isolate the effect of the along-string friction from the bit-rock interaction, field data from rotational start-ups after a connection (with bit off bottom) is considered. This high frequency surface and downhole data is then used to validate the surface and downhole behavior predicted by the model. The model is shown to have a good match with the surface and downhole behavior of two deviated wellbores for depths ranging from 1500 to 3000 meters. In particular, the model replicates the amplitude and period of the oscillations, in both the topside torque and the downhole RPM, as caused by the along-string stick slip. It is further shown that by using the surface behavior of the drill-string during rotational startup, an estimate of the static and dynamic friction factors along the wellbore can be obtained, even during stick-slip oscillations, if axial tension in the drillstring is considered. This presents a possible method to estimate friction factors in the field when off-bottom stick slip is encountered, and points in the direction of avoiding stick slip through the design of an appropriate torsional start-up procedure without the need of an explicit friction test.

scholarly journals Stability of PDF Controller With Stick-Slip Friction Device

1997 ◽  
Vol 119 (3) ◽  
pp. 486-490 ◽  
Author(s):  
Jia-Yush Yen ◽  
Chih-Jung Huang ◽  
Shu-Shung Lu
Keyword(s):  
Control Algorithm ◽  
Controller Design ◽  
System Model ◽  
Pole Placement ◽  
Order System ◽  
Stick Slip ◽  
Precision Control ◽  
Experimental Works ◽  
The Stability ◽  
Control Accuracy

This paper presents the precision control of drive devices with significant stick-slip friction. The controller design follows the Pseudo-Derivative Feedback (PDF) control algorithm. Using the second order system model, the PDF controller offers arbitrary pole placement. In this paper, the stability proof for the controller with stick-slip friction is presented. On the basis of this proof, the stability criteria are derived. The paper also includes both the computer simulation and the experimental works to confirm the theoretical result. The experiments conducted on a Traction Type Drive Device (TTDD) shows that control accuracy of as high as ±1 arc – second is achieved.

Chilled Water Temperature Control of HVAC System Using GPC Based Controller

2012 ◽  
Vol 151 ◽  
pp. 626-631
Author(s):  
Qiang Ma ◽  
Jian Gang Lu ◽  
Qin Min Yang ◽  
Jin Shui Chen ◽  
You Xian Sun
Keyword(s):  
Predictive Control ◽  
Pid Controller ◽  
Closed Loop ◽  
Controller Design ◽  
Simulation Environment ◽  
Closed Loop System ◽  
Satisfactory Performance ◽  
Chilled Water ◽  
The Stability ◽  
Theoretical Results

This work proposes a generalized predictive control (GPC) based controller for the temperature of HVAC chilled water supply. In this paper, several models of evaporator are firstly introduced, wherein an identified black-box model is selected for the purpose of controller design. Based on this model, a GPC based controller is employed to obtain a satisfactory performance even with the presence of disturbance. The theoretical results show the stability of the closed-loop system and the performance of this scheme is compared with that of traditional PID controller under simulation environment.

scholarly journals A closed-loop multi-level model of glucose homeostasis

PLoS ONE ◽  
2018 ◽  
Vol 13 (2) ◽  
pp. e0190627 ◽  
Author(s):  
Cansu Uluseker ◽  
Giulia Simoni ◽  
Luca Marchetti ◽  
Marco Dauriz ◽  
Alice Matone ◽  
...  
Keyword(s):  
Glucose Homeostasis ◽  
Closed Loop ◽  
Level Model ◽  
Multi Level

scholarly journals Gain scheduled controller design for thermo-optical plant

2014 ◽  
Vol 24 (3) ◽  
pp. 333-349 ◽  
Author(s):  
Vojtech Veselý ◽  
Jakub Osuský ◽  
Ivan Sekaj
Keyword(s):  
Output Feedback ◽  
Closed Loop ◽  
Controller Design ◽  
Design Method ◽  
Feedback Gain ◽  
Small Gain ◽  
Gain Scheduled Controller ◽  
The Stability ◽  
Gain Scheduled ◽  
Siso Systems

Abstract This paper presents a gain scheduled controller design for MIMO and SISO systems in the frequency domain using the genetic algorithms approach. The proposed method is derived from the M-delta structure of closed loop MIMO (SISO) systems and the small gain theory is exploited to obtain the stability condition. An example of real system illustrates the effectiveness of the proposed output feedback gain scheduled controller design method and also the possibility to improve its performance using the genetic algorithm

scholarly journals Robust adaptive controller design for excavator arm

2019 ◽  
Vol 8 (4) ◽  
pp. 293
Author(s):  
Nga Thi-Thuy Vu
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Lyapunov Stability Theory ◽  
Adaptive Controller ◽  
Closed Loop System ◽  
Model Free ◽  
Lagrange Form ◽  
Robust Adaptive ◽  
The Stability ◽  
Robust Adaptive Controller

This paper presents a robust adaptive controller that does not depend on the system parameters for an excavator arm. Firstly, the model of the excavator arm is demonstrated in the Euler-Lagrange form considering with overall excavator system. Next, a robust adaptive controller has been constructed from information of state error. In this paper, the stability of overall system is mathematically proven by using Lyapunov stability theory. Also, the proposed controller is model free then the closed loop system is not affected by disturbances and uncertainties. Finally, the simulation is executed in Matlab/Simulink for both presented scheme and the PD controller under some conditions to ensure that the proposed algorithm given the good performances for all cases.

Bounded-Input-Bounded-Output Stability of Nonlinear Feedback Systems in a Volterra Representation

2000 ◽  
Author(s):  
John W. Glass ◽  
Matthew A. Franchek
Keyword(s):  
Stability Condition ◽  
Closed Loop ◽  
Controller Design ◽  
External Disturbance ◽  
Design Procedure ◽  
Nonlinear Feedback ◽  
Feedback Systems ◽  
Volterra Kernels ◽  
The Stability ◽  
Nonlinear Feedback Systems

Abstract Presented in this paper is a stability condition for a class of nonlinear feedback systems where the plant dynamics can be represented by a finite series of Volterra kernels. The class of Volterra kernels are limited to p-linear stable operators and may contain pure delays. The stability condition requires that the linear kernel is nonzero and that the closed loop characteristic equation associated with the linearized system is stable. Next, a sufficient condition is developed to upper bound the infinity-norm of an external disturbance signal thereby guaranteeing that the internal and output signals of the closed loop nonlinear system are contained in L∞. These results are then demonstrated on a design example. A frequency domain controller design procedure is also developed using these results where the trade-off between performance and stability are considered for this class of nonlinear feedback systems.

Design of Variable Structure Control with Bounded Inputs

2010 ◽  
Vol 29-32 ◽  
pp. 1175-1180
Author(s):  
Qing Kun Zhou ◽  
Sheng Jian Bai ◽  
Zhi Yong Zhang
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Sliding Mode ◽  
Variable Structure ◽  
Closed Loop System ◽  
Variable Structure Systems ◽  
Structure Control ◽  
Variable Structure System ◽  
Lti System ◽  
The Stability

The design of variable structure system inputs which are constrained by saturation is studied. For a LTI system which satisfies some conditions, it is shown that appropriate bounded controllers guarantee the system’s global stability and maximize the sliding mode domain on the switching surfaces. Stability conditions of variable structure systems with constrained inputs are relaxed, and the stability of the closed-loop system is guaranteed by using passivity theory of linear passive systems. Moreover, nonlinear sliding surfaces are discussed for variable structure controller design, and a novel nonlinear switching surface is proposed. Finally, the proposed methods are applied to a 2nd order LTI system to show their usefulness.

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