摘要
During engineering practice and theoretical research, the mechanism degree of freedom is sometimes unequal to the number of the driving link, which is unable to be explained according to the classic theory of the mechanism degree of freedom. To solve this problem, the duality description for operating laws of mechanism is introduced based on the concepts of duality. The Junction-Structure Equation is established for the port descriptions of general ideal mechanism and the functional description for the mechanism degree of freedom is described by utilization of bond graph theory. The force-transfer de- gree of freedom, i.e. the antithesis concept of movement-transfer degree of freedom, is introduced and defined based on the analysis of energy transfer as well as the analysis of signal causality. By utiliza- tion of structural description, functional description and duality description for the equation of degree of freedom, the relationship between the movement-transfer degree of freedom and force-transfer de- gree of freedom is further explored and analyzed. Thus, the relationship between the mechanism de- gree of freedom upon the driving link and the executive link is described generally. Finally, some typical relationships between the mechanism degree of freedom, the driving link and the executive link are analyzed.
During engineering practice and theoretical research, the mechanism degree of freedom is sometimes unequal to the number of the driving link, which is unable to be explained according to the classic theory of the mechanism degree of freedom. To solve this problem, the duality description for operating laws of mechanism is introduced based on the concepts of duality. The Junction-Structure Equation is established for the port descriptions of general ideal mechanism and the functional description for the mechanism degree of freedom is described by utilization of bond graph theory. The force-transfer degree of freedom, i.e. the antithesis concept of movement-transfer degree of freedom, is introduced and defined based on the analysis of energy transfer as well as the analysis of signal causality. By utilization of structural description, functional description and duality description for the equation of degree of freedom, the relationship between the movement-transfer degree of freedom and force-transfer degree of freedom is further explored and analyzed. Thus, the relationship between the mechanism degree of freedom upon the driving link and the executive link is described generally. Finally, some typical relationships between the mechanism degree of freedom, the driving link and the executive link are analyzed.
基金
Supported by the National Basic Research Program of China (973 Program) (Grant Nos. 2007 CB 707706 and 2006CB705400)
the National Natural Science Foun-dation of China (Grant No. 50475139)
