Clearance at turning pair has a strong impact on the kinetic accuracy of linkage,but there is short of a generic model to analyze it so far.Clearance error,input error,and manufacturing tolerance of links are taken into consideration as the random variables synthetically.The kinematics and dynamics accuracy analysis models for planar linkages with multiple clearances at joints are built up as well.At last a typical planar linkage is selected for numerical illustration.These models stated in matrix resolve the relativity of output parameter errors of mechanism and therefore are of vital significance for the reliability analysis and synthesis of mechanism with clearances.
Adaptable design aims to extend the utilities of design and product.The specific methods are developed for practical applications of adaptable design in the design of mechanical structures, including adaptable platform,interface and module designs.Adaptable redesign problems are formulated as adaptable platform design under adaptability bound constraints.Analysis tools are then suggested for the implementation of the redesign of machine tool structures,including variation techniques based sensitivity analysis,similarity-based commonality analysis,performance improvement,and adaptability measures.The specific measure of adaptability for machine tool structures is measured through the quantification of the structural similarity and performance improvement gained from adaptable design.The method provides designers with an approach that brings adaptability into the design process,with considering the cost and benefits of such adaptability. The redesign of CNC spiral bevel gear cutting machine structures has been included to illustrate these concepts and methods.
