Based on structural properties and genetic isomorphism-identification approach, this paper proposes a classification scheme of kinematic structures to categorize the kinematic chains into different families, thus faci...Based on structural properties and genetic isomorphism-identification approach, this paper proposes a classification scheme of kinematic structures to categorize the kinematic chains into different families, thus facilitating the optimum selection of a basic structure of a mechanism. The kinematic chain is represented by a graph at first. The genetic adaptive model for the graph isomorphism identification is developed, which includes the construction of an effective method to decrease the problem's dimensions and applying an evolutionary searching strategy. From the various invariants of the genetic adaptive model, which charaterize the specific features of a kinematic chain or a family of kinematic chains, we obtain a six-step hierarchical classification scheme. This scheme classifies together the kinematic chains having similar sub-sets of structures forming isomorphic sub-chains. An example illustrates the theory, procedure and utitlity of the hierarchical classification. The scheme reduces computing time and effort in the optimum selection of a kinematic structure from a large family of kinematic chains.展开更多
This paper presents a mechanism theory principle for equivalent substitution in kinematic chain of a higher pair for lower pairs. This is the opposite of the principle of the equivalent substitution of lower pairs for...This paper presents a mechanism theory principle for equivalent substitution in kinematic chain of a higher pair for lower pairs. This is the opposite of the principle of the equivalent substitution of lower pairs for a higher pair. Also presented here is a new approach for isomorphism identification in kinematic chains containing higher pairs(KCCHs). Based on this approach, an algorithm for generating nonisomorphic KCCHs has been developed. This algorithm is not restricted by the number of links, the degree of freedom or the number of higher pairs. Using this algorithm, nonisomorphic KCCHs can be generated automatically from the kinematic chains that contain only lower pairs. As an application of this algorithm, all the nonisomorphic KCCHs with N<10(N, the number of links), F≤3 (F, the degree of KCCHs), and H≤2(H, the number of higher pairs) are computer generated.展开更多
文摘Based on structural properties and genetic isomorphism-identification approach, this paper proposes a classification scheme of kinematic structures to categorize the kinematic chains into different families, thus facilitating the optimum selection of a basic structure of a mechanism. The kinematic chain is represented by a graph at first. The genetic adaptive model for the graph isomorphism identification is developed, which includes the construction of an effective method to decrease the problem's dimensions and applying an evolutionary searching strategy. From the various invariants of the genetic adaptive model, which charaterize the specific features of a kinematic chain or a family of kinematic chains, we obtain a six-step hierarchical classification scheme. This scheme classifies together the kinematic chains having similar sub-sets of structures forming isomorphic sub-chains. An example illustrates the theory, procedure and utitlity of the hierarchical classification. The scheme reduces computing time and effort in the optimum selection of a kinematic structure from a large family of kinematic chains.
文摘This paper presents a mechanism theory principle for equivalent substitution in kinematic chain of a higher pair for lower pairs. This is the opposite of the principle of the equivalent substitution of lower pairs for a higher pair. Also presented here is a new approach for isomorphism identification in kinematic chains containing higher pairs(KCCHs). Based on this approach, an algorithm for generating nonisomorphic KCCHs has been developed. This algorithm is not restricted by the number of links, the degree of freedom or the number of higher pairs. Using this algorithm, nonisomorphic KCCHs can be generated automatically from the kinematic chains that contain only lower pairs. As an application of this algorithm, all the nonisomorphic KCCHs with N<10(N, the number of links), F≤3 (F, the degree of KCCHs), and H≤2(H, the number of higher pairs) are computer generated.
