scholarly journals The Investigation on Non-linear Characteristic of Yawing Moment of Twin-tailed Configuration

2013 ◽  
Vol 67 ◽  
pp. 347-356 ◽  
Author(s):  
Y.K. Wang ◽  
Y. Qin ◽  
X.Y. Deng ◽  
X. Huang
1971 ◽  
Vol 4 (9) ◽  
pp. T151-T157 ◽  
Author(s):  
P D Roberts

The paper describes a digital simulation study of the application of a non-linear controller to the regulation of a single stage neutralisation process. In the controller, the proportional gain increases with amplitude of controller error signal. The performance of the non-linear controller is compared with that of a conventional linear controller and with the performance obtained by employing a linear controller with a linearisation network designed to compensate for the non-linear characteristic of the neutralisation curve. Although the performance of the non-linear controller is inferior to that obtained by employing a perfect linearisation network, its performance is still considerably superior to that obtained by using a conventional linear controller when operating at a symmetrical point on the neutralisation curve. In contrast to the linearisation network technique, the non-linear controller contains only one extra parameter and can be readily tuned on-line without prior knowledge of the neutralisation curve. Hence, it can be considered as an attractive alternative for the control of neutralisation processes.


1995 ◽  
Vol 10 (4) ◽  
pp. 215-230 ◽  
Author(s):  
G.H. Nie ◽  
Y.K. Cheung

A non-linear stability problem of imperfect reticulated shallow shells with distorted rectangular meshes is investigated in this paper. The fundamental governing equations are deduced by adopting an equivalent model and the principle of the virtual work. For the reticulated shallow spherical shell under uniform vertical load, an axisymmetrical case is considered and the analytical solution of the coupled equations is given with the help of the asymptotical iteration method. Meanwhile, non-linear characteristic relations concerning load, deflection and imperfection factor are numerically analyzed. In particular, the corresponding solution degenerates to that of a reticulated circular plate when the radius of curvature of the structure R → ∞.


2017 ◽  
Vol 11 (6) ◽  
pp. 1427-1433 ◽  
Author(s):  
Ming Yang ◽  
Wenxia Sima ◽  
Qing Yang ◽  
Jianbiao Li ◽  
Mi Zou ◽  
...  

2000 ◽  
Vol 15 (1) ◽  
pp. 53-58 ◽  
Author(s):  
G. H. Nie

This paper presents an asymptotic analysis on non-linear free vibrations of single-layer reticulated shallow spherical shells composed of beam members placed in two orthogonal directions with the aid of a continuum model proposed by the author. By introducing a parameter variable which is determined by solving a cubic single-variable equation for the case of axisymmetry, the fundamental governing equations can be exactly satisfied. The asymptotic iteration method has been adopted to obtain an analytical solution for a non-linear characteristic relation between the amplitude and frequency of the structure. Numerical examples are given, and the phenomena indicating softening and hardening of such structures have been presented for various values of radius of curvature (or apex rise) of hinged or clamped spherical shells.


Author(s):  
Tomasz Pajchrowski ◽  
Konrad Urbański ◽  
Krzysztof Zawirski

PurposeThe aim of the paper is to find a simple structure of speed controller robust against drive parameters variations. Application of artificial neural network (ANN) in the controller of PI type creates proper non‐linear characteristics, which ensures controller robustness.Design/methodology/approachThe robustness of the controller is based on its non‐linear characteristic introduced by ANN. The paper proposes a novel approach to neural controller synthesis to be performed in two stages. The first stage consists in training the ANN to form the proper shape of the control surface, which represents the non‐linear characteristic of the controller. At the second stage, the PI controller settings are adjusted by means of the random weight change (RWC) procedure, which optimises the control quality index formulated in the paper. The synthesis is performed using simulation techniques and subsequently the behaviour of a laboratory speed control system is validated in the experimental set‐up. The control algorithms of the system are performed by a microprocessor floating point DSP control system.FindingsThe proposed controller structure with proper control surface created by ANN guarantees expected robustness.Originality/valueThe original method of robust controller synthesis was proposed and validated by simulation and experimental investigations.


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