Solving Fuzzy Error Matrix Equation based on Runge Kutta Method

2021 ◽  
Vol 7 (5) ◽  
pp. 2146-2157
Author(s):  
Jing Meng

Fuzzy error logic represents the object in the real world with (u, x) as <inline-formula><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="M2"><mml:mrow><mml:mfenced close="}" open="{"><mml:mrow><mml:mfenced close="]" open="["><mml:mrow><mml:mi>U</mml:mi><mml:mo>,</mml:mo><mml:mi>S</mml:mi><mml:mfenced><mml:mi>t</mml:mi></mml:mfenced><mml:mo>,</mml:mo><mml:mtext> </mml:mtext><mml:mover><mml:mi>p</mml:mi><mml:mi>r</mml:mi></mml:mover><mml:mo>,</mml:mo><mml:mi>T</mml:mi><mml:mfenced><mml:mi>t</mml:mi></mml:mfenced><mml:mo>,</mml:mo><mml:mi>L</mml:mi><mml:mfenced><mml:mi>t</mml:mi></mml:mfenced></mml:mrow></mml:mfenced><mml:mo>,</mml:mo><mml:mfenced close="]" open="["><mml:mrow><mml:mi>x</mml:mi><mml:mfenced><mml:mi>t</mml:mi></mml:mfenced><mml:mo>=</mml:mo><mml:mi>f</mml:mi><mml:mfenced><mml:mrow><mml:mi>u</mml:mi><mml:mfenced><mml:mi>t</mml:mi></mml:mfenced><mml:mo>,</mml:mo><mml:mi>p</mml:mi></mml:mrow></mml:mfenced><mml:mo>,</mml:mo><mml:mi>G</mml:mi><mml:mi>u</mml:mi><mml:mfenced><mml:mi>t</mml:mi></mml:mfenced></mml:mrow></mml:mfenced></mml:mrow></mml:mfenced></mml:mrow></mml:math></inline-formula>, Fuzzy error transformation matrix can be used to express six transformation methods, such as decomposition, similarity, addition, replacement, destruction and unit transformation. Based on solving equation XA=B and decomposition of p, this paper studies the solution of error matrix equation based on Runge Kutta method, in order to explore the law of error transformation from the perspective of solving matrix equation.

Author(s):  
Jialin Tian ◽  
Jie Wang ◽  
Yi Zhou ◽  
Lin Yang ◽  
Changyue Fan ◽  
...  

Abstract Aiming at the current development of drilling technology and the deepening of oil and gas exploration, we focus on better studying the nonlinear dynamic characteristics of the drill string under complex working conditions and knowing the real movement of the drill string during drilling. This paper firstly combines the actual situation of the well to establish the dynamic model of the horizontal drill string, and analyzes the dynamic characteristics, giving the expression of the force of each part of the model. Secondly, it introduces the piecewise constant method (simply known as PT method), and gives the solution equation. Then according to the basic parameters, the axial vibration displacement and vibration velocity at the test points are solved by the PT method and the Runge–Kutta method, respectively, and the phase diagram, the Poincare map, and the spectrogram are obtained. The results obtained by the two methods are compared and analyzed. Finally, the relevant experimental tests are carried out. It shows that the results of the dynamic model of the horizontal drill string are basically consistent with the results obtained by the actual test, which verifies the validity of the dynamic model and the correctness of the calculated results. When solving the drill string nonlinear dynamics, the results of the PT method is closer to the theoretical solution than that of the Runge–Kutta method with the same order and time step. And the PT method is better than the Runge–Kutta method with the same order in smoothness and continuity in solving the drill string nonlinear dynamics.


2021 ◽  
pp. 101554
Author(s):  
Tomasz Bochacik ◽  
Maciej Goćwin ◽  
Paweł M. Morkisz ◽  
Paweł Przybyłowicz

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