Transmission Analysis Of Planar Single DOF Multi-loop Mechanism

To complete the performance evaluation and configuration synthesis for planar single DOF multi-loop mechanisms,firstly,this paper make configuration synthesis.On the basis of structure analysis,a new index of transmission is presented.The optimization design of planar single DOF multi-loop mechanisms is established on the base of the proposed index of transmission.The main research content is as follows:(1)The configuration synthesis of planar single DOF multi-loop mechanisms is conducted based on the adjacency matrix of Assur group.On the basis,the planar single DOF multi-loop mechanism with higher pairs is obtained by replacing low pair with higher pair.According to the specific movement and position requirements,the feasible configurations are selected,and the specific configurations are got by embodying the high pairs.An effective method for configuration synthesis is provided to the planar single DOF multi-loop mechanisms with higher pairs.(2)A model of relationship between input and output links in Assur group is defined through the structural analysis of planar single DOF multi-loop mechanisms,then the model of relationship between input and output links in planar single DOF multi-loop mechanism according to the connected relation between the Assur groups.Thus make the problem of solving transmission of mechanisms convert into the problem of solving transmission of Assur groups and their connected relation.(3)Based on the concept ‘virtual coefficient' in screw theory,the transmission of Assur group is defined through the ratio between actual instantaneous transmission power and the maximum theoretical transmission power.Then the index of transmission of planar single DOF multi-loop mechanism is given according to the model of relationship between input and output links.The index of transmission can be used to compare the transmission between different mechanisms with different dimensions and provide theory basis for the design of mechanism.(4)On the base of the proposed index of transmission of planar single DOF multi-loop mechanisms,the optimization design model of cam-linkage mechanism is established,with the structural geometry features as constraint conditions and the transmission index and horizontal size as the optimization objects.Then with the multi-objective constrained optimization algorithm,a set of homogeneous dimensionless parameters is got,which can make the structure size more compact and transmission index much better.