| The parallel mechanism is a type of mechanism composed of dynamic and static platforms and multiple limbs.It has the advantages of being different from the serial mechanism,such as high stiffniss,high precision,and simple control.The kinematic redundant part can make the mechanism achieve the purpose of avoiding singular positions and expanding the workspace by changing the parameters of the redundant part and adjusting the configuration of the mechanism.The flexible member can transmit the force and torque through its deformation,with low wear and high precision And other advantages,which can effectively reduce the actuating torque of the mechanism.By combining the structural redundant parallel mechanism and the flexible mechanism,a new rigid-flexible coupled structural redundant parallel mechanism is established to achieve the purpose of optimizing the performance of the mechanism,and can maintain the structural advantages of the rigid and flexible mechanism.Based on the above background,this paper selects a structural redundant parallel mechanism,theoretically analyzes its kinematics,determines the selection of flexible links by simulation,and conducts a series of analyses on the rigid-flexible coupling parallel mechanism.Finally,verify the characteristics of the mechanism by making physical objects.The specific research tasks are as follows:(1)This paper analyzes the kinematics of the selected kinematic redundant parallel mechanism.Through the study of the closed ring of the limb,the relationship between the structural parameters in the limb can be solved,and the inverse solution of the position,singularity,workspace and dexterity of the mechanism can be obtained.And analyze the influence of the parameter change of the kinematic redundant part on the motion performance of the mechanism,and prove the characteristics of the mechanism that the mechanism can avoid the singular positions through simulation.(2)Analyzing the structure of the mechanism,the stiffness matrix can be obtained.And to build a model of its flexibility,the flexibility matrix of the mechanism can be obtained.Through simulation analysis in Adams software,compare the effects of the three links in the fully rigid mechanism and the rigid-flexible coupling mechanism on the actuating torque of the mechanism,and select the link that produces the best performance for the mechanism as the flexible link.Perform finite element modeling for the rigid-flexible coupling mechanism,and perform static stiffness analysis on it with a certain load.(3)The dynamic analysis of the mechanism is carried out,and the Lagrangian equation is selected to model the dynamics of the mechanism.The kinetic energy expression and the gravitational potential energy expression of the fully rigid model and the rigid-flexible coupled model are solved.Set up a simulation action,and compare and analyze the theoretical value and simulation value of the mechanism actuating torque.(4)The physical production of the mechanism,through its structural design,circuit design and control system construction,which can obtain the physical model of the 3-DOF kinematics redundant parallel mechanism.The control program is designed with three typical actions of the mechanism to verify its kinematic characteristics. |
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