Uncertain Friction-Induced Vibration Study: Coupling of Fuzzy Logic, Fuzzy Sets, and Interval Theories

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Franck Massa ◽  
Hai Quan Do ◽  
Thierry Tison ◽  
Olivier Cazier
Keyword(s):  
Fuzzy Logic ◽  
Stability Problem ◽  
Extension Principle ◽  
Vibration System ◽  
Fuzzy Logic Controllers ◽  
Output Data ◽  
Projection Techniques ◽  
The Stability ◽  
Interval Problems ◽  
Friction Induced Vibration

This paper presents a complete method to carry out a fuzzy study of a friction-induced vibration system and to analyze the effects of uncertainty on the output data of a stability problem. The proposed approach decomposes the fuzzy problem into interval problems and calculates interval output solutions by optimization. Next, each calculation of the stability problem output data, which is useful during the optimization process, is reanalyzed by integrating fuzzy logic controllers for the static step and homotopy development and projection techniques for the modal step. Finally, the obtained results are compared with Zadeh’s extension principle reference.

Fuzzy Logic Based Vehicle Stability Enhancement Through Combined Differential Braking and Active Front Steering

2005 ◽  
Author(s):  
J. Ahmadi ◽  
A. Ghaffari ◽  
R. Kazemi
Keyword(s):  
Fuzzy Logic ◽  
Steering System ◽  
Vehicle Stability ◽  
Fuzzy Logic Controllers ◽  
Vehicle Model ◽  
Active Front Steering ◽  
Highly Nonlinear ◽  
Road Condition ◽  
The Stability ◽  
Stability Enhancement

This paper examines the usefulness of a combined differential braking and active front steering system on the stability enhancement of a vehicle. The two manipulated inputs for steering intervention are the added front steer angle and the brake torque, where the later is applied at only one wheel at a time. In this study active front steering controller is designed independent of differential braking controller. Since the yaw and lateral motions are highly nonlinear, two fuzzy logic controllers are constructed to compensate the effects of road condition and parameter variation. Computer simulations using nonlinear seven degree of freedom vehicle model show the strong capability of the combined approach and its relative merit compared to the case that one subsystem is actuated.

scholarly journals INVESTIGATION OF INTELLIGENT CONTROLLER FOR NON-LINEAR SPHERICAL TANK SYSTEM

2021 ◽  
Vol 9 (2) ◽  
pp. 1053-1061
Author(s):  
Ajith B. Singh, Et. al.
Keyword(s):  
Fuzzy Logic ◽  
Volume Ratio ◽  
Cost Effective ◽  
Effluent Treatment ◽  
Fuzzy Logic Controllers ◽  
Spherical System ◽  
Spherical Tank ◽  
Tank System ◽  
The Stability ◽  
Logic Controllers

Spherical tanks are used to store fluids in many industries such as petrochemical, effluent treatment, and aerospace. Spherical tanks are used as they are highly resistant to internal pressure making them suitable for storing high-pressure materials due to their large volume, small weight, and strong load-bearing capacity. The spherical tanks have the lowest possible surface area to volume ratio. These tanks are preferred due to their capability of balancing pressure in and out of the tank and their ability to minimize the amount of heat that gets inside the tank wall. It is cost-effective when compared to other tanks. But, controlling the water level in the spherical tank is difficult and a highly challenging one. In this article, the aim is to stabilize the level of the spherical tank by using the PID and FUZZY logic controllers. By controlling nonlinear dynamic behavior, uncertainty, time-varying parameters, frequency disturbances and dead time, the stability of the tank is achieved. The mathematical modelling of the spherical system is obtained using first principles design and the stability of the model is analyzed using various techniques. Then, the simulation is done using MATLAB and the responses are obtained and compared for PID and FUZZY logic. Based on these comparisons made on the performance of the PID and FUZZY logic controllers, the results are concluded

scholarly journals The two-dimensional hydrodynamical theory of moving aerofoils. IV

1947 ◽  
Vol 188 (1015) ◽  
pp. 439-463
Keyword(s):  
Stability Problem ◽  
Two Dimensional ◽  
Centre Of Gravity ◽  
First Approximation ◽  
Von Karman ◽  
Moving Cylinder ◽  
Period Equation ◽  
The Stability ◽  
Von Kármán ◽  
Hydrodynamical Theory

In the first part of this paper opportunity has been taken to make some adjustments in certain general formulae of previous papers, the necessity for which appeared in discussions with other workers on this subject. The general results thus amended are then applied to a general discussion of the stability problem including the effect of the trailing wake which was deliberately excluded in the previous paper. The general conclusion is that to a first approximation the wake, as usually assumed, has little or no effect on the reality of the roots of the period equation, but that it may introduce instability of the oscillations, if the centre of gravity of the element is not sufficiently far forward. During the discussion contact is made with certain partial results recently obtained by von Karman and Sears, which are shown to be particular cases of the general formulae. An Appendix is also added containing certain results on the motion of a vortex behind a moving cylinder, which were obtained to justify certain of the assumptions underlying the trail theory.

Some Structural Properties of Systolic Tree Automata

1989 ◽  
Vol 12 (4) ◽  
pp. 571-585
Author(s):  
E. Fachini ◽  
A. Maggiolo Schettini ◽  
G. Resta ◽  
D. Sangiorgi
Keyword(s):  
Structural Properties ◽  
Stability Problem ◽  
Sufficient Condition ◽  
Tree Automata ◽  
Necessary And Sufficient Condition ◽  
The Stability ◽  
Necessary And Sufficient

We prove that the classes of languages accepted by systolic automata over t-ary trees (t-STA) are always either equal or incomparable if one varies t. We introduce systolic tree automata with base (T(b)-STA), a subclass of STA with interesting properties of modularity, and we give a necessary and sufficient condition for the equivalence between a T(b)-STA and a t-STA, for a given base b. Finally, we show that the stability problem for T(b)-ST A is decidible.

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