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Determination Of Space Centrode Of A Coupler Link

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1996 Annual Conference


Washington, District of Columbia

Publication Date

June 23, 1996

Start Date

June 23, 1996

End Date

June 26, 1996



Page Count


Page Numbers

1.147.1 - 1.147.6



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Paper Authors

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R. R. Reynolds

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Glynn P. Adams

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Ing-Chang Jong

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NOTE: The first page of text has been automatically extracted and included below in lieu of an abstract

I -+-. Session 2668

Determination of Space Centrode of a Coupler Link

I. C. Jong, R. R. Reynolds, and G. P. Adams University of Arkansas


In kinematics, the velocity center of the coupler link of a four-bar linkage in a collinear configuration can- not be determined solely by the traditional method of velocity center. Such a difficulty is a singularity and a baffling situation in the teaching of dynamics. This paper points out that three alternative approaches can be used to resolve this difficulty. The determination of the space centrode of the coupler link of the system considered in- volves the solution of two simultaneous transcendental equations and is carried out by using the software Math- ematica.


Suppose that the crank AB of the four-bar linkage shown in Fig. 1 rotates with a given angular velocity COAB = -81 k radls

We note that such a linkage has no range of lockup positions. It was shown in earlier studies by Jongl’z that the angular velocities of the coupler link BD and the output link DE in a collinear configuration, as shown in Fig. 2, are not amenable to solutions by the traditional method of veloci~ center alone, or by the method of linkage eqw.- tion for velocities alone. These angular velocities were first solved by the usage of a perturbation method,l and then by the combined usage of the method of linkage equation for velocities and the method of linkage equation for accelerations.2

Based on the studies of Jongla, it is clear that the velocity center C of the coupler link BD in a collinear configuration can be determined by the following two alternative approaches: (1) usage of a perturbation method, (2) combined usage of the method of linkage equation for velocities and the method of linkage equation for accel- erations. A third alternative approach to determine such a velocity center C is presented in this paper. Specifically, this one is termed approach (3): combined usage of the method of velocity center and the method of linkage equa- tion for velocities. Notice that approaches (2) and (3) differ in the combination of methods used.


Fig. 1 A four-bar linkage with the crank AB in its first revolution . . _ {hx~~ 1996 ASEE Annual Conference Proceedings ‘.+,~TMlc..$

Reynolds, R. R., & Adams, G. P., & Jong, I. (1996, June), Determination Of Space Centrode Of A Coupler Link Paper presented at 1996 Annual Conference, Washington, District of Columbia. 10.18260/1-2--5973

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