Planar Linkage Synthesis for Function Generation Using Poles and Rotation Angles

Author(s):  
Ronald A. Zimmerman

Function Generation is a long standing linkage design problem. It is possible to design a planar four bar linkage whose input and output links will pass through seven coordinated positions. This paper discloses the first graphical solution to this problem. The approach is to consider the constraints imposed by the target positions on the linkage through the poles and rotation angles. This approach enables the designer to explore the range of possible solutions when fewer than seven positions are specified by dragging a fixed or moving pivot in the plane. The selection of free choices is made at the end of the process and the complete mechanism is visible when the choices are made. The constraints only need to be made once which eliminates the repetitive construction required by previous methods to consider multiple pivot locations. Since it is so easy to consider multiple pivot locations and the solution mechanism is visible, the required design time is greatly reduced. A corresponding analytical solution is also developed and solved based on the same constraints. This is a new analytical solution and is defined by a system of 20 nonlinear equations with 20 unknowns.

Author(s):  
Ronald A. Zimmerman

Coupler point path guidance is a long standing linkage design problem. It is possible to design a four bar linkage with a coupler point that will pass through up to nine specified points. This paper discloses a new graphical solution to this problem. The approach is to consider the constraints imposed by the target points on the linkage through the poles and rotation angles. This approach enables the designer to explore the range of possible solutions when fewer than nine points are specified by dragging a fixed or moving pivot in the plane. The selection of free choices is made at the end of the process and the complete mechanism is visible when the choices are made. The constraints only need to be made once which eliminates the repetitive construction required by previous methods to consider multiple pivot locations. Since it is so easy to consider multiple pivot locations and the solution mechanism is always visible, the required design time is greatly reduced. A corresponding analytical solution is also developed and solved based on the same constraints. The analytical solution is defined by a system of 28 nonlinear equations with 28 unknowns.


Author(s):  
Ronald A. Zimmerman

The kinematic synthesis of planar linkage mechanisms has traditionally been broken into the categories of motion, path and function generation. Each of these categories of problems has been solved separately. Many problems in engineering practice require some combination of these problem types. For example, a problem requiring coupler points and/or poses in addition to specific input and/or output link angles that correspond to those positions. A limited amount of published work has addressed some specific underconstrained combinations of these problems. This paper presents a general graphical method for the synthesis of a four bar linkage to satisfy any combination of these exact synthesis problems that is not over constrained. The approach is to consider the constraints imposed by the target positions on the linkage through the poles and rotation angles. These pole and rotation angle constraints are necessary and sufficient conditions to meet the target positions. After the constraints are made, free choices which may remain can be explored by simply dragging a fixed pivot, a moving pivot or a pole in the plane. The designer can thus investigate the family of available solutions before making the selection of free choices to satisfy other criteria. The fully constrained combinations for a four bar linkage are given and sample problems are solved for several of them.


2018 ◽  
Vol 10 (2) ◽  
Author(s):  
Ronald A. Zimmerman

The kinematic synthesis of planar linkage mechanisms has traditionally been broken into the categories of motion, path, and function generation. Each of these categories of problems has been solved separately. Many problems in engineering practice require some combination of these problem types. For example, a problem requiring coupler points and/or poses in addition to specific input and/or output link angles that correspond to those positions. A limited amount of published work has addressed some specific underconstrained combinations of these problems. This paper presents a general graphical method for the synthesis of a four bar linkage to satisfy any combination of these exact synthesis problems that is not overconstrained. The approach is to consider the constraints imposed by the target positions on the linkage through the poles and rotation angles. These pole and rotation angle constraints (PRCs) are necessary and sufficient conditions to meet the target positions. After the constraints are made, free choices which may remain can be explored by simply dragging a fixed pivot, a moving pivot, or a pole in the plane. The designer can thus investigate the family of available solutions before making the selection of free choices to satisfy other criteria. The fully constrained combinations for a four bar linkage are given and sample problems are solved for several of them.


1959 ◽  
Vol 81 (4) ◽  
pp. 293-296
Author(s):  
W. W. Worthley ◽  
R. T. Hinkle

An analytical method for synthesizing a four-bar linkage as a function generator is presented. The method, which permits the arbitrary selection of four precision points and finite angular ranges, is based on a graphical solution. This permits a preliminary graphical investigation of the six possible linkages before selecting one for analytical treatment.


Author(s):  
Jong-Won Kim ◽  
Jeongae Bak ◽  
TaeWon Seo ◽  
Jongwon Kim

This paper presents a new angular transmission device based on a four-bar linkage mechanism. This mechanism consists of a four-bar linkage and an output gear similar to the Geneva drive. When the input link of the four-bar linkage is rotated once, the trajectory of the coupler point is generated. Then, the coupler point drives the motion of the output gear. To rotate the output gear by a specific angle, the design of the four-bar linkage is very important. The mechanism was generated using a new method for four-bar linkage design. Unlike some conventional methods, the new method can consider both the trajectory and the velocity of a coupler point. The new device has two advantages compared to the Geneva drive. Firstly, because the positions of the input and output axes are close to each other, the space efficiency of the new device is higher than that of the Geneva drive. Secondly, the duty factor of the new device is larger than that of the Geneva drive, and the mechanical loads applied to the output gear, such as that from acceleration, are much lower. Kinematic and dynamic simulation analysis was conducted to verify the advantages of the new device.


1965 ◽  
Vol 87 (2) ◽  
pp. 170-176 ◽  
Author(s):  
C. K. Wojcik

The function generation method presented in this paper is based on consideration of the equations of motion of a four-bar linkage with an assumed input of θ˙1 = 1 rad/sec. For a specified input-output relationship, the task of synthesizing an appropriate four-bar linkage is reduced by this method to a problem of selecting two parameters: θ˙2—the angular velocity and θ¨2—the angular acceleration of the connecting rod. The selection of these parameters is governed by certain conditions imposed on the performance of the four-bar linkage function generator. Using this method, two specific problems are solved and discussed in detail.


2015 ◽  
Vol 39 (3) ◽  
pp. 637-646
Author(s):  
Ren-Chung Soong

A hybrid-driven five-bar linkage mechanism with one input cycle corresponding to two output cycles is presented. The proposed linkage mechanism is driven by a constant-speed motor and a linear motor, respectively. The output link can generate two same required output cycles during a single input cycle, while the rotational input link rotates with a constant angular speed, and the linear input link follows a reciprocating motion along a specified linear guide fixed on the rotational input link. The configuration, displacement relationship between the input and output links, and conditions of mobility of this proposed mechanism were studied, and a kinematic analysis was performed. The selection of the instantaneous motion trajectory of the linear input link and an optimal dimensional synthesis are also described. An example is provided to verify the feasibility and effectiveness of this methodology.


2004 ◽  
Vol 31 (3-4) ◽  
pp. 265-280 ◽  
Author(s):  
Radovan Bulatovic ◽  
Stevan Djordjevic

This paper considers optimal synthesis of a four-bar linkage by method of controlled deviations. The advantage of this approximate method is that it allows control of motion of the coupler in the four-bar linkage so that the path of the coupler is in the prescribed environment around the given path on the segment observed. The Hooke-Jeeves?s optimization algorithm has been used in the optimization process. Calculation expressions are not used as the method of direct searching, i.e. individual comparison of the calculated value of the objective function is made in each iteration and the moving is done in the direction of decreasing the value of the objective function. This algorithm does not depend on the initial selection of the projected variables. All this is illustrated on an example of synthesis of a four-bar linkage whose coupler point traces a straight line, i.e. passes through sixteen prescribed points lying on one straight line. .


Author(s):  
SM Varedi-Koulaei ◽  
H Rezagholizadeh

This paper presents a method for path generation synthesis of a four-bar linkage that includes both graphical and analytical synthesis and both cases of with and without prescribed timing. The advantage of the proposed method over available techniques is that it is easier and does not need the complicated process (especially in graphical case). In an analytical solution, this method needs the solution of the linear equations, unlike the previous methods, in that they have required the solution of the nonlinear equations. Moreover, in the current method, one can choose the shape of the coupler, while, in other methods, the shape of the coupler is the result of the solution process. The proposed algorithm can be used for path generation synthesizing of a four-bar linkage for three precision points.


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