科研之友
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摘要
This work describes a new top-down design method for the stiffness of precision machine tools that considers the entire machine stiffness to guarantee the stiffness requirements in the initial design stage. A stiffness modelling method and a stiffness matching design method are presented to achieve the top-down design of the stiffness. A new stiffness characterisation using the stiffness coefficients for characterising the stiffness of the structural parts and the functional units is proposed. The deformation model of the entire machine is established based on multi-body system theory, and the equations of the stiffness coefficients for the deformations of the components are established based on the simultaneous equations of the static equilibrium equations, the deformation compatibility equations and the physical equations. The three-direction (3D) stiffness model is obtained by substituting the equations into the deformation model that reflects the stiffness characteristics of the machine tool. Thus, the reliability of the stiffness model is verified by experiments. Next, the stiffness matching design is performed to confirm the reasonable stiffness values of the parts based on the stiffness model. The finite element method (FEM) is used to validate the proposed method. The contribution rate of the stiffness of the parts to the stiffness of the entire machine is analysed.
