Design of Centric Drag-Link Mechanisms for Delay Generation With Focus on Space Occupation

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Abdullah F. Al-Dwairi
Keyword(s):  
Length Ratio ◽  
Link Length ◽  
Link Mechanism ◽  
Maximum Delay ◽  
Transmission Angle ◽  
Quality Of Motion ◽  
Nonuniform Rotation ◽  
Drag Link ◽  
Space Occupation

Planar drag-link mechanism is a Grashofian four-bar chain with the shortest link fixed. In practice, the mechanism is used as a coupling between two shafts to convert uniform rotation of the driving shaft into a nonuniform rotation of the driven shaft. The nonuniformity in rotation is characterized by a cyclically increasing and decreasing delay (or advance) in the displacement of the driven shaft relative to that of the driving shaft. Drag-link synthesis problems include synthesizing the mechanism to generate a specified maximum delay. In a drag-link mechanism, the longer links make a full rotation about fixed pivots, which results in a relatively large installation space. This calls for designing drag-link mechanisms with a focus on space occupation, along with the traditional criteria of quality of motion transmission. Using position analysis, we investigate the relationships among mechanism space occupation, extreme transmission angle, and the generated maximum delay. Space occupation is represented by the link-length ratio of input link to fixed link. Given a desired maximum delay, the proposed approach suggests finding a unique extreme transmission angle value for which this link-length ratio is at a minimum. A closed-form solution to drag-link synthesis to generate a specified maximum delay is developed based on a compromise between quality of motion transmission and space occupation. For any drag-link designed by this compromise, the coupler link and the output crank are of the same length. Based on the obtained design equations, a graphical design solution and a method for evaluating space occupation are provided.

Design of Drag-Link Mechanisms With Optimum Transmission Angle

1983 ◽  
Vol 105 (2) ◽  
pp. 254-258 ◽  
Author(s):  
Lung-Wen Tsai
Keyword(s):  
Extreme Values ◽  
Angular Displacement ◽  
Output Link ◽  
Link Length ◽  
Design Charts ◽  
Link Mechanism ◽  
Transmission Angle ◽  
New Criterion ◽  
Four Bar Linkage ◽  
Drag Link

In this paper, a new criterion for the design of a drag-link mechanism with optimum transmission angle is established. The transmission angle, the angle between the coupler link and output link of a four-bar linkage, is considered to be optimized when its extreme values deviate equally from 90 deg. Based on this criterion, design equations and design charts are developed. It is shown that the optimum drag-link mechanism is a turning-block linkage. It is also shown that to displace the drag-link mechanism with optimum transmission angle from its minimum lag to its maximum lag position, the input link must always rotate 180 deg and the corresponding angular displacement of the output link depends only on the link-length ratio of the output link to the fixed-link.

Optimum Design of the Crank Rocker Four Bar Mechanism for Specified Output Oscillation Angle and Timing Ratio

1987 ◽  
Author(s):  
D. H. Suchora ◽  
G. Wrightson
Keyword(s):  
Optimum Design ◽  
Cycle Time ◽  
Geometric Construction ◽  
Length Ratio ◽  
Total Output ◽  
Link Length ◽  
Analytic Construction ◽  
Transmission Angle ◽  
Work First ◽  
Parameters Of Interest

Abstract In designing a crank rocker four bar mechanism with a uniform input rotation typical input parameters are the required total output oscillation angle and the timing ratio of the advance to return cycle time. In determining an optimum design the parameters of interest are usually the extreme transmission angles and the ratio of the longest to shortest link length occuring in the mechanism. This work first develops an analytic construction of the link lengths and worst transmission angles based on the necessary geometry for a given output angle of oscillation and required timing ratio. The resulting equations are programmed and graphs developed which give the variation of extreme transmission angle and maximum link length ratio as a function of the specified output angle of oscillation, timing ratio, and geometric construction variables. Using these graphs a designer will be able to easily select optimum designs based on worst transmission angles and link length ratios. Examples are included.

The Design of the Spherical Drag-Link Mechanism

1967 ◽  
Vol 89 (1) ◽  
pp. 177-181 ◽  
Author(s):  
A. H. Soni ◽  
L. Harrisberger
Keyword(s):  
Design Chart ◽  
Link Mechanism ◽  
Transmission Angle ◽  
Drag Link

The spherical drag-link mechanism has been designed using an approach based on minimum transmission angle. Explicit relationships have been derived for the required dimensions which satisfy the criteria of minimum transmission angle, and a design chart for the solution of spherical drag-link mechanisms (similar to that of Hain) is presented. Also, the seven cognates of the spherical drag-link mechanisms are identified and discussed.

Design of Drag-Link Mechanisms With Minimax Transmission Angle Deviation

1983 ◽  
Vol 105 (4) ◽  
pp. 686-690 ◽  
Author(s):  
L.-W. Tsai
Keyword(s):  
Optimum Design ◽  
Design Criterion ◽  
Parameter Design ◽  
Cubic Equation ◽  
Design Charts ◽  
Link Mechanism ◽  
Transmission Angle ◽  
Angle Deviation ◽  
Drag Link ◽  
Maximum Transmission

In this paper, the design equations are derived for the synthesis of a drag-link mechanism, with given output-link rotation and the corresponding input-link rotation. The design criterion used is based on the maximum capability of a drag-link mechanism to provide a given delay or advance in the output motion. The solutions are given as a single-valued parametric set of equations for the link lengths. The transmission-angle optimization is accomplished by the minimization of the maximum transmission-angle deviation from 90 deg. It is shown that the optimum design can be obtained by solving a cubic equation in a single parameter. Design charts for the optimum design of a drag-link mechanism were developed. It is also shown that there is a one-to-one correspondence between the design of a crank-and-rocker mechanism and the drag-link mechanism.

Multi-objective reliability-based optimal synthesis of path generating four-bar mechanisms: A cooperative game theoretic approach

2021 ◽  
pp. 095440622110289
Author(s):  
Bahman Ahmadi ◽  
Behzad Ahmadi ◽  
Saeed Nezamivand Chegini ◽  
Leili Safari
Keyword(s):  
Cooperative Game ◽  
Tracking Error ◽  
Optimal Synthesis ◽  
Performance Criteria ◽  
Theoretic Approach ◽  
Multi Objective ◽  
Text Quality ◽  
Transmission Angle ◽  
Quality Of Motion

In this study, a novel approach based on synergy of cooperative game theory, reliability-based design optimization (RBDO) and Monte Carlo simulation (MCS) is proposed to address the reliability-based multi-objective optimal synthesis of path generating four-bar mechanisms, taking into account the influence of dimensional uncertainty on the reliability of mechanism. Tracking error ([Formula: see text]), deviation of transmission angle from 90° ([Formula: see text]) and probability of failure of Grashof constraint are defined as three performance criteria whose minimization enhance the precision, quality of motion and reliability of mechanism, respectively. To do so, three objective functions are considered, namely, precision ([Formula: see text]), quality of motion ([Formula: see text]) and reliability ([Formula: see text]); each objective function is assigned to a player. To conduct the optimization procedure, a game model is proposed, in which the cooperative game scenario is employed by defining a Nash bargaining function to model the interaction between players. In this way, the three-objective optimum design of mechanism is cast into a single-objective optimization problem. The comparisons of the obtained results using the method of this research with those reported in the literature shows a significant improvement in reliability of mechanism, whilst both precision and quality of motion in deterministic design is maintained. Particularly, the tracking error and the deviation of transmission angle from 90° of the synthesized mechanism is 0.0006 and 666.36 respectively, whilst the reliability is guaranteed since no violation of Grashof constraint occurs in the presence of 10% parameter uncertainty.

Comparison of diagnostic quality of motion picture experts group–2 digital video with super VHS videotape for echocardiographic imaging

2003 ◽  
Vol 16 (8) ◽  
pp. 880-883 ◽  
Author(s):  
Kevin M Harris ◽  
Kevin R Schum ◽  
Thomas Knickelbine ◽  
David G Hurrell ◽  
Jodi L Koehler ◽  
...  
Keyword(s):  
Motion Picture ◽  
Digital Video ◽  
Diagnostic Quality ◽  
Quality Of Motion ◽  
Group 2

scholarly journals Using Length of Bilge Keel to Length of Waterline Ratio to Reduce Ship Rolling Motion

2018 ◽  
Vol 8 (2) ◽  
pp. 2731-2734
Author(s):  
P. K. D. N. Y. Putra ◽  
B. H. Iskandar ◽  
Y. Novita
Keyword(s):  
Good Stability ◽  
Length Ratio ◽  
Rolling Motion ◽  
Fishing Vessels ◽  
Bilge Keel ◽  
Minimum Ratio ◽  
Ship Rolling

Fishing vessels must have good stability and manoeuvrability. Hull with round bottom shape has a relatively poor rolling duration compared to other forms. Rolling duration reduction will improve the quality of stability of the ship which can be obtained with bilge keel installation. The objectives of this research are 1) to compare each parameter value on model ship by using bilge keel and 2) to determine the minimum ratio of bilge keel's length toward waterline length on the model ship which still has the ability to reduce rolling motion on the ship. The method used was giving treatment to model ship and observing its rolling motion with different lengths of bilge keel. Based on the result of the research, it can be concluded that bilge keel installation with some length ratio toward length of waterline has different results significantly, and bilge keel with length ratio 0.2 still have effective capability in reducing the rolling motion of the model ship.

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