Plane four clubs institutions of Sports performance research
Abstract:The planar four-bar linkages are one type of basic mechanisms, and they are applied very extensively. The performances of the linkages depend on their geometrical parameters and present the complicated non-linear relations. It is necessary to make the further research on them for analysis, synthesis and application of linkages.By using of the three-dimensional models of the planar four-bar mechanisms, the actual sizes of mechanisms are transformed relative ones, and all size types of mechanisms can be figured by spatial coordinates. It is the foundation for research on the relations between the link dimensions and kinematic capability parameters.Aimed at the different characteristics of crank-rocker mechanism, double-crank mechanism, double-rocker mechanism and single-slider mechanism, some inherent relations between the link dimensions and the kinematic capability parameters are deeply analyzed, then the relative kinematic capability diagrams are obtained.Based on deeply analysis of inherent relations between the extreme position angle and the link dimensions of typeⅠand typeⅡcrank-rocker mechanisms with quick return characteristics, the geometrical conditions are put forward in this paper, by which we can judge whether the extreme position angle of typeⅠcrank-rocker mechanisms is less than, equal to or lager than 90°. It is proved that the extreme position angle of typeⅡcrank-rocker mechanism is certainly less than 90°. The relations between the extreme position angle and the angular stroke of the rocker are brought to light, which should be satisfied during the kinematic design of crank-rocker mechanisms.The diagrams and conclusions obtained in this paper provide theoretic foundation for the capability analysis and synthesis of mechanisms.
Keyword: Planar four-bar linkage Space model Sports Performance
