Target Optimization Design of Cam Curve in Zoom System

2013 ◽  
Vol 552 ◽  
pp. 44-51
Author(s):  
Chen Wei Ning ◽  
Cao Jian Zhong ◽  
Yang Hong Tao ◽  
Zhang Jian ◽  
Fan Zhe Yuan ◽  
...  
Keyword(s):  
Optimization Design ◽  
Rotation Angle ◽  
Optical Design ◽  
Zoom Lens ◽  
Pressure Angle ◽  
Cam Design ◽  
System A ◽  
Cam Follower ◽  
Optimization Function ◽  
The Stability

Zoom lens has been widely applied in all kinds of fields, and its cam optimization is the key to actualizing the performance of its optical design and the zooming process, while the smoothness and speediness of zooming movement must be considered for military and civilian use. With the incremental use of environmental requirements, it puts forward higher requests to the cam performance of lens. In order to guarantee that the cam has good stiffness in the case of vibration and shock environment, in the process of cam design, it not only requires curve optimal, but also needs to consider influence on the performance which is caused by reduced cam stiffness of the zoom system. A fine curve can ensure that the cam pressure angle α is smaller, and to ensure the cam follower maintains the uniform velocity and smaller acceleration in zooming process, and make the zoom system produce little impact, and whole zooming process smooth and fluent, it can reduce the zoom systems driving moment M, and can ensure the stability imaging of the zoom system. Good cam stiffness K can make the zoom lens have good stability in vibration environment, and make sure that the image quality. M and K respectively up to the pressure angle α of zoom curve and the rotation angle θ of zoom curve in cam. In the new cam design process, considering the whole influence on the performance that is caused by K and M to cam, we construct the function expressions K = f (α, θ) and M = f (α, θ), and then, build target optimization function with K and M, optimize the relationship between pressure angle α of zoom curve and rotation angle θ, looking for the optimal value for the stiffness K and the cam system driving moment M , and improve overall performance of the zoom cam .

NPLs — The Solution Recipe for Albania

2015 ◽  
Vol 3 (1) ◽  
pp. 48
Author(s):  
Elona Shehu ◽  
Elona Meka
Keyword(s):  
Interest Rate ◽  
Negative Relationship ◽  
Banking System ◽  
Gdp Growth ◽  
System A ◽  
Analysis Technique ◽  
Recent Financial Crisis ◽  
The Stability ◽  
Asset Quality ◽  
Macroeconomic Determinants

The quality of the loan portfolio in Albanian banking system is facing many obstacles during the last decade. In this paper we look at possible determinants of assets quality. During the recent financial crisis commercial banks were confronted with deteriorating asset quality that threatened not only the banking industry, but also the stability of the entire financial system. This study aims to examine the correlation between non-performing loans and the macroeconomic determinants in Albania during the last decade. NPLs are considered to be of a high importance as they represent the high risk exposure of banking system. A solid bank with healthy assets increases the market efficiency. Our approach is based on a panel data regression analysis technique from 2005-2015. Within this methodology this study finds robust evidence on the existing relationship between lending interest rate, real GDP growth and NPLs. We expect to find a negative relationship between lending interest rate and asset quality. Further we assume an inverse relationship between GDP growth and non-performing loans, suggesting that NPLs decrease if the economy is growing. Furthermore this study proposes a solution platform, which looks deeper into the possibility of creating a secondary active market for troubled loans, restructuring the banking system or implementing the Podgorica model. This research paper opens a new lieu of discussion in terms of academic debates and decision-making policies.

Towards a new design with generic modeling and adaptive control of a transformable quadrotor

2021 ◽  
pp. 1-31
Author(s):  
S.H. Derrouaoui ◽  
Y. Bouzid ◽  
M. Guiatni
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Experimental Tests ◽  
Generic Model ◽  
System Control ◽  
System A ◽  
Viable Solution ◽  
Generic Modeling ◽  
Adaptive Control Strategy ◽  
The Stability

Abstract Recently, transformable Unmanned Aerial Vehicles (UAVs) have become a subject of great interest in the field of flying systems, due to their maneuverability, agility and morphological capacities. They can be used for specific missions and in more congested spaces. Moreover, this novel class of UAVs is considered as a viable solution for providing flying robots with specific and versatile functionalities. In this paper, we propose (i) a new design of a transformable quadrotor with (ii) generic modeling and (iii) adaptive control strategy. The proposed UAV is able to change its flight configuration by rotating its four arms independently around a central body, thanks to its adaptive geometry. To simplify and lighten the prototype, a simple mechanism with a light mechanical structure is proposed. Since the Center of Gravity (CoG) of the UAV moves according to the desired morphology of the system, a variation of the inertia and the allocation matrix occurs instantly. These dynamics parameters play an important role in the system control and its stability, representing a key difference compared with the classic quadrotor. Thus, a new generic model is developed, taking into account all these variations together with aerodynamic effects. To validate this model and ensure the stability of the designed UAV, an adaptive backstepping control strategy based on the change in the flight configuration is applied. MATLAB simulations are provided to evaluate and illustrate the performance and efficiency of the proposed controller. Finally, some experimental tests are presented.

Study on the Global Bifurcation of Quasi-Zero-Stiffness System

2013 ◽  
Vol 397-400 ◽  
pp. 451-456
Author(s):  
Qing Chao Yang ◽  
Li Hua Yang ◽  
Yan Ping Chen ◽  
Hao Kai Lai
Keyword(s):  
Optimization Design ◽  
Global Bifurcation ◽  
Mapping Method ◽  
Exciting Force ◽  
Force Frequency ◽  
Force Amplitude ◽  
System A ◽  
Wide Range ◽  
Chaos Motion ◽  
Dynamics Approximation

According to the characteristics of the quasi zero stiffness (QZS) system, a dynamics approximation model is established. The effect of excitation force amplitude, frequency and stiffness on the dynamic characteristics of the system is studied by continuation algorithm. The global bifurcation diagram with a wide range of parameters is achieved by using Poincaré mapping method. Results show that when the exciting force amplitude increases to a certain extent, the system will come into multi-cycle and chaos motion state. When exciting force frequency is lower, the system dynamic behavior is complicated, which is helpful for the engineering optimization design.

Spline Based Design of Cam Contours for Improved Dynamic Performance

1993 ◽  
Author(s):  
Holly K. Ault ◽  
James C. Wilkinson
Keyword(s):  
Dynamic Performance ◽  
Integrated Design ◽  
Polynomial Functions ◽  
Piecewise Polynomial ◽  
Cam Design ◽  
Piecewise Polynomial Functions ◽  
Cam Follower ◽  
Cam Profile ◽  
Pitch Curve ◽  
Design And Manufacture

Abstract A method for the integrated design and manufacture of radial plate cams is discussed. Currently, a cam-follower system is designed by specifying constraints on the motion of the follower. The physical cam contour or cam pitch curve are not mathematically defined. The cam is manufactured from the discretized follower motion program. A new method for cam design is proposed which will produce a smooth, mathematically defined cam pitch curve while maintaining the proper constraints on the follower motion. Piecewise polynomial functions in the form of rational and/or non-rational splines may be used. Cams will be manufactured using smoothed profiles and tested for improved dynamic performance. The results of initial investigations of cam profile design for this research are presented.

Study on Self-Excited Vibration Mechanism of Wheel-Rail Lateral Contact System

2013 ◽  
Vol 427-429 ◽  
pp. 257-261
Author(s):  
Li Xia Sun ◽  
Jian Wei Yao ◽  
Fu Guo Hou ◽  
Xin Zhao
Keyword(s):  
Feedback Mechanism ◽  
Point Of View ◽  
Contact System ◽  
Vibration System ◽  
Lateral Contact ◽  
System A ◽  
Vibration Model ◽  
Excited Vibration ◽  
Vibration Mechanism ◽  
The Stability

In order to investigate self-excited vibration mechanism of wheel-rail lateral contact system, a two DOF elasticity position wheelset lateral vibration model is established which considers the dry friction; the mechanism of the wheelset lateral self-excited vibration is investigated from the energy point of view. It shows that: the bifurcation diagram of this wheel-rail lateral contact system has a supercritical Hopf bifurcation. The energy of self-excited vibration derives from a part of traction energy; the creep rate in the wheel-rail system act as a feedback mechanism in the wheelset lateral self-excited vibration system. The stability of the wheelset self-excited vibration system depends mainly on the total energy removed from and imported into the system.

Solving Vlasov-Poisson-Fokker-Planck Equations using NRxx method

2017 ◽  
Vol 21 (3) ◽  
pp. 782-807 ◽  
Author(s):  
Yanli Wang ◽  
Shudao Zhang
Keyword(s):  
Splitting Method ◽  
Linear Convergence ◽  
Mass Conservation ◽  
System A ◽  
Spectral Convergence ◽  
The Stability ◽  
The Moment ◽  
Stability And Accuracy ◽  
Fokker Planck Equations ◽  
Fokker Planck

AbstractWe present a numerical method to solve the Vlasov-Poisson-Fokker-Planck (VPFP) system using the NRxx method proposed in [4, 7, 9]. A globally hyperbolic moment system similar to that in [23] is derived. In this system, the Fokker-Planck (FP) operator term is reduced into the linear combination of the moment coefficients, which can be solved analytically under proper truncation. The non-splitting method, which can keep mass conservation and the balance law of the total momentum, is used to solve the whole system. A numerical problem for the VPFP system with an analytic solution is presented to indicate the spectral convergence with the moment number and the linear convergence with the grid size. Two more numerical experiments are tested to demonstrate the stability and accuracy of the NRxx method when applied to the VPFP system.

Optical design of the high-power zoom lens

2014 ◽  
Vol 21 (6) ◽  
pp. 745-751
Author(s):  
Daisuke Ito
Keyword(s):  
High Power ◽  
Optical Design ◽  
Zoom Lens

scholarly journals Socio-Political Aspects of Russian Muslim Pilgrimage to Mecca in the XIX-Th Century

2020 ◽  
Vol 38 (Especial II) ◽  
pp. 47-57
Author(s):  
Anvar Ajratovich Gafarov ◽  
Mariam Arslanovna Galeeva
Keyword(s):  
19Th Century ◽  
Special Role ◽  
System A ◽  
Russian State ◽  
Holy Places ◽  
Expert Assessments ◽  
Confessional Identity ◽  
The Stability ◽  
Political Economic ◽  
The 19Th Century

Starting from the middle of the 16-th century, during the foreign policy expansion increase, the ethno-confessional diversity of the Russian state was steadily increasing. The imperial policy aimed at assimilating non-Russian peoples sharply raised the issue of their identity preservation. For domestic Muslims, an important factor in cultural and confessional identity provision was the preservation and development of their traditional ties with the Islamic world. Various political, economic, cultural, and other contacts maintained with the countries of the Muslim East have become the basis for the stability of the Muslim community in Russia under imperial pressure. In this system, a special role was originally played by the Hajj (Muslim pilgrimage to the holy places in the Hejaz), which the official administration had to reckon with. The aim of the proposed study is to identify socio-political aspects, socio-political conditions, and the specifics of the Hajj implementation in the 19th century. After the analysis of office documentation, travel notes of Muslim pilgrims, and expert assessments of orientalists, the authors concluded that, despite the increasing opposition from the authorities, the significance of the Hajj intensifies in the 19th century. Hajj became not only the factor of opposition to imperial acculturation, but also a channel for presentation the ideas of renewal.

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