The Research And Applications Of The Structure And Kinematics Of Metamorphic Mechanisms

The metamorphic mechanism is a new type of mechanism derived from artistic origami,which has the change of the number of members,the change of configuration and the change of degrees of freedom.The structure and kinematics of metamorphic mechanisms are analyzed.The main research contents include:the configuration description method of the metamorphic mechanism,the design of the metamorphic joint(aV joint),the structural analysis of the parallel metamorphic mechanism,the motion analysis of the metamorphic mechanism,and the practical application of the metamorphic mechanism.First of all,in order to solve the problem that the general adj acency matrix is not comprehensive in describing the configuration change of the metamorphic mechanism,a new method for describing the change of the configuration of the metamorphic mechanism is proposed.The traditional adj acency matrix is combined with the motion screw code to form a new motion screw coding adjacency matrix describing the change of the configuration of the metamorphic mechanism.A matrix operation method describing the change process of the configuration of the metamorphic mechanism is proposed.Second,a new type of metamorphic joint(aV joint)is designed.The new metamorphic joint has four different configurations,which can be transformed into six different joints,which are equivalent to different spherical joint,Hook joint and revolute joint.The metamorphic limb composed of the metamorphic joint also has metamorphic characteristics.By analyzing six different metamorphic limbs(aV)PS,two different types of metamorphic limbs can be obtained.Two limbs with different conformations in two types of limbs are analyzed,the configuration and the change of degree of freedom are realized by the parallel metamorphic mechanism composed of them.The degree of freedom analysis of the parallel metamorphic mechanism is carried out by the theory of motion screw.All the configurations of the parallel metamorphic mechanism 3-(aV)PS are analyzed,and the parallel metamorphic mechanism 3-(aV)PS in the same layout has 4 different degrees of freedom,10 different configurations and 56 different forms.Then,the kinematics of metamorphic mechanism is analyzed,and the essential difference between kinematics of metamorphic mechanism and kinematics of general mechanism is analyzed.It is concluded that the key problem in the analisys of kinematics of metamorphic mechanism is to establish the transformation and recursive relationship of kinematic variables between two adjacent topologies.By analyzing the Huston low-order array method,which describes the topological changes of the metamorphic mechanism,the homogeneous matrix method of kinematics is combined with the Huston low-order array method to obtain the recursive relationship of the motion variables between different configurations of the metamorphic mechanism.Finally,the practical application of the metamorphic mechanism and the parallel metamorphic mechanism are illustrated with seversal examples.The research content of this subject make the theory of the metamorphic mechanisms configuration description rich,and the type of the metamorphic mechanism expanded,which lays a theoretical foundation for the practical application of the metamorphic mechanism.