Study On Dynamics Of The Ultra-precision Fly-cutting Machine Tool Based On Transfer Matrix Method For Multibody Systems

Rui method,namely transfer matrix method for multibody systems(MSTMM),is a novel method for multibody system dynamics put forward and developed in the past three decades.MSTMM not only avoids the global dynamics equation but also has the advantages of low involved matrix order,high computational speed,high formalized programmability.Thus,MSTMM was worldwide applied on over 150 kinds of products in 52 fields whose theory and application are still developed.As significant research achievements in the Science Challenge Project in China,the ultra-precision fly-cutting machine tool is the research object in this thesis.MSTMM is developed and then applied to dynamics of the ultra-precision fly-cutting machine tool from theory,computation and test.The main contributions of this thesis are as follows:(1)The reduced transfer matrix method for multibody systems with spatial plates is proposed creatively.The direction cosine matrix is employed in transfer matrices of spatial plates so that the proposed method can conduct the vibration analysis of rectangular plates,parallelogram plates and multi-plate systems.The proposed method is a computationally efficient and stable dynamic modeling method for analyzing the natural vibration of multibody systems with spatial plates.(2)A hybrid dynamics method combining MSTMM with finite element method and modal synthesis method is established,which extends MSTMM in the computational field of general flexible multibody systems.The improved determinant algorithm is put forward to deal with the overflow problem usually encountered in solving the eigenvalue equation.(3)Transfer equations and transfer matrices of general flexible body elements with multi-input ends are deduced.Automatic deduction of the overall transfer equation,the orthogonality of augmented eigenvectors for flexible multibody systems are developed,which enriches the theories and ranges of MSTMM.(4)The dynamics model and overall transfer equation of the ultra-precision fly-cutting machine tool system are established by proposed methods.The natural vibration characteristics and dynamics response of the ultra-precision fly-cutting machine tool are simulated effectively,and the influence of the overall structural parameters of the system on the ultra-precision machining accuracy was revealed by the computation and experiment.Optimization of dynamics parameters is implemented to improve the ultra-precision machining accuracy,resulting in an 18.06% decrease in the Peak-to-valley value of the machined surface.Based on the dynamics of the ultra-precision fly-cutting machine tool,the secondary activepassive isolation of the environmental vibration and active control of the the tool tip vibration are designed and simulated,which provides a theoretical basis for the design of ultra-precision machine tools.