| The linkage mechanism plays a significant role in the study of mechanisms,and its applications tend to be diversified,resulting in numerous research topics.This project was commissioned by a company to design a transmission mechanism that can realize multiple forms of motion through the linkage mechanism.In the design of crank and rocker mechanism,the rocker is required as a motion input,how to determine the length of each rod to meet the crank can achieve the whole circumference of the rotation is a difficult research point,so it is of great significance to synthesize and optimize the mechanism scale of crank and rocker mechanism and to analyze the kinematics and dynamics characteristics of the whole test device from the perspective of mathematical modeling and simulation.In this paper,based on the current status of domestic and foreign research on the linkage mechanism,the degrees of freedom of the transmission mechanism are analyzed in conjunction with the working principle of the test device.The dimensions of the crank rocker mechanism are optimized by using mathematical calculation software to obtain multiple sets of locally optimal solutions for the rod length under the constraint conditions,then the scale optimization is carried out for the above locally optimal solutions,and the most suitable rod length data are preferentially selected according to the indexes with the best force transmission performance.The motion of the space linkage mechanism is decomposed into the motion of the plane linkage mechanism in multiple planes,and the kinematic analysis of the mechanism is carried out by the analytical method in modules,and the expressions of the kinematic characteristics such as displacement and angular displacement of each component are obtained,and the specific kinematic characteristic curves of each member are derived by using Maple software to verify that the kinematic characteristics of the relevant members obtained by numerical calculation meet the requirements of kinematic design.According to the functional expressions between different parameters of each component,the dynamics equation of the test device is established by Lagrange’s equation,which is solved in reverse for the given initial conditions to obtain the specific variation law of the driving torque to be applied to the test device when a given resistance torque and rotational speed motion are input.The kinematic and kinetic simulations of the rigid body model and the rigid-flexible coupled model of the power transmission test device were carried out using ADAMS software.The kinematic simulations yielded kinematic characteristic curves such as displacements and angular displacements,while the kinetic simulations yielded the required driving moments and the variation of the forces on the components when moving according to a given motion law.The simulation results of the rigid body model are basically the same as the analytical calculation results,which confirm the correctness of the relevant functional equations and kinetic equations obtained from the rigid body simulation model and numerical calculations. |
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