Metamorphic mechanisms have attracted considerable attention owing to their capability to switch their topology to adapt to different operational tasks.One feature of topological change is the re-contact of different ...Metamorphic mechanisms have attracted considerable attention owing to their capability to switch their topology to adapt to different operational tasks.One feature of topological change is the re-contact of different bodies,which inevitably causes collisions affecting operation accuracy and service life.Consequently,in this study,a collision incidence matrix was introduced to describe the topology of a system involved in collisions,and a method for reducing the closed-loop system to an open-loop system was proposed.The complex movement of the metamorphic mechanism in a changing topology was classified into two different running stages of the source metamorphic mechanism.Based on the relative coordinate method,dynamic modeling of the source metamorphic mechanism considering the impact effects was conducted.Combining the classical collision theory and Newton–Euler equation,the generated impact impulse and the motion after collision were determined.Subsequently,a dynamic analytical method for the full configuration of metamorphic mechanisms was proposed to reflect the changes in the topological structure in the dynamic model.Finally,two typical metamorphic mechanisms used in packaging and spinning were considered as examples to verify the correctness and effectiveness of the proposed method,and their impact characteristics during configuration transformation were analyzed.The proposed analytical method of internal impact for a variable topology process provides effective theoretical guidance for the stability analysis of configuration transformation and structural design aimed at minimizing impacts.展开更多
The concept of metamorphic mechanisms is presented, configuration models and configuration transformations relating to a set of new matrix operations are discussed and proposed. The configuration of a metamorphic mech...The concept of metamorphic mechanisms is presented, configuration models and configuration transformations relating to a set of new matrix operations are discussed and proposed. The configuration of a metamorphic mechanism reflects the connectivity change in the mechanism during motions which results in mobility change and presents the characteristics of the mechanism which is discussed in various applications particularly in decorative artifacts. The characteristics is further investigated with mobility analysis.展开更多
A method based on the metamorphic principle is proposed for the analysis of the configuration design of a space truss deployable mechanism. The configuration change and correspondent topological graphs and adjacency m...A method based on the metamorphic principle is proposed for the analysis of the configuration design of a space truss deployable mechanism. The configuration change and correspondent topological graphs and adjacency matrixes at different work-stage of the mechanism, which is helpful to completely understand the composition and change rules of the metamorphic mechanism, are analyzed to indicate the metamorphic relationship in one working cycle. Furthermore, the static distance matrix, dynamic distance matrix and stiffness matrix of the mechanism are derived to assess the ability of the designed configuration to reveal some of the topological characteristics like compactness, dynamic sensitivity and stiffness. Using this proposed method in a space truss deployable mechanism helps the designer to evaluate its performance at the conceptual stage of design and make a rapid, reasonable selection for configuration design, which provides means for processing its type of analysis by computer.展开更多
基金Supported by National Natural Science Foundation of China(Grant Nos.52005368,51475330)。
文摘Metamorphic mechanisms have attracted considerable attention owing to their capability to switch their topology to adapt to different operational tasks.One feature of topological change is the re-contact of different bodies,which inevitably causes collisions affecting operation accuracy and service life.Consequently,in this study,a collision incidence matrix was introduced to describe the topology of a system involved in collisions,and a method for reducing the closed-loop system to an open-loop system was proposed.The complex movement of the metamorphic mechanism in a changing topology was classified into two different running stages of the source metamorphic mechanism.Based on the relative coordinate method,dynamic modeling of the source metamorphic mechanism considering the impact effects was conducted.Combining the classical collision theory and Newton–Euler equation,the generated impact impulse and the motion after collision were determined.Subsequently,a dynamic analytical method for the full configuration of metamorphic mechanisms was proposed to reflect the changes in the topological structure in the dynamic model.Finally,two typical metamorphic mechanisms used in packaging and spinning were considered as examples to verify the correctness and effectiveness of the proposed method,and their impact characteristics during configuration transformation were analyzed.The proposed analytical method of internal impact for a variable topology process provides effective theoretical guidance for the stability analysis of configuration transformation and structural design aimed at minimizing impacts.
文摘The concept of metamorphic mechanisms is presented, configuration models and configuration transformations relating to a set of new matrix operations are discussed and proposed. The configuration of a metamorphic mechanism reflects the connectivity change in the mechanism during motions which results in mobility change and presents the characteristics of the mechanism which is discussed in various applications particularly in decorative artifacts. The characteristics is further investigated with mobility analysis.
基金supported by the Science and Technology Commission of Shanghai Municipality under Grant No. 06dz22105
文摘A method based on the metamorphic principle is proposed for the analysis of the configuration design of a space truss deployable mechanism. The configuration change and correspondent topological graphs and adjacency matrixes at different work-stage of the mechanism, which is helpful to completely understand the composition and change rules of the metamorphic mechanism, are analyzed to indicate the metamorphic relationship in one working cycle. Furthermore, the static distance matrix, dynamic distance matrix and stiffness matrix of the mechanism are derived to assess the ability of the designed configuration to reveal some of the topological characteristics like compactness, dynamic sensitivity and stiffness. Using this proposed method in a space truss deployable mechanism helps the designer to evaluate its performance at the conceptual stage of design and make a rapid, reasonable selection for configuration design, which provides means for processing its type of analysis by computer.
