Flexible Multi-Body Model Of Heavy Duty Machine Tool And Error Algorithm

Gantry Mobile Turning and Milling Machining Center is used to process nuclear parts, Head of Water Chamber. For Heavy Duty Machine Tool, reliability of assembly process is a premise of precision implementation. Evaluation index of assembly process mainly is Geometric error, Location error and Cutting error. At present, error control method usually uses means of detection, identification, compensation, which is a remedy of oversize after assembly, couldn’t solve the fundamental problem from assembly source.In the paper, on the basis of error modeling theory and related research results, to achieve high geometric accuracy, positioning accuracy, conducted a study of geometric error and positioning error modeling and assembly process control methods by using Multi-body System Theory, Factor Analysis, Fractal Geometry, Modal Analysis.According to complexity of load transfer for heavy duty machine tool, using topology principle, establishing topology of machine tool, forming incidence matrix and lower body array.In a motor function of machine tool, establish constraint equation of prismatic and rotary.when the part are assumed as flexible body, using transfer matrix method of Multi-body System Theory, establishing transfer equation of internal and contact load, forming kinetic equation of machine tool.Error sources of Geometric Error using ADAMS are recognized.It is solved for the shape and position error sources and contact error sources using Factor Analysis.analysis on the formation of heavy machine tool assembly geometry errors,according to assembly process data,with order of position,preload and contact,machine tool in ADAMS is assembled,extract pose value of post-installation and solve some Geometric Error of Vertical Boring and Milling Head,Knife,Beams and Gantry,a evaluation method of Geometric Error is proposed using Contour Method combined with measurement experiment of error.Analyses on positioning movement of heavy machine tools, key factors are recognized. According to Statistical meaning of re-orientation accuracy, study on location Variation of transmission stiffness, contact stiffness, dynamic static friction coefficient, and form and position error, put forward some cause of re-orientation accuracy. On the basis of geometric error model,position error are resolved for X,Y,Z axis of Gantry Mobile Turning and Milling Machining Center considering positioning error source.Basis for national standard,bidirectional location precision,bidirectional re-orientation accuracy and reverse difference are solved, detection method of location precision is given. Effectiveness of Multi-body System Model is verified using Modal Analysis.On the basis of geometric error model, key joint surface are identified using Response Analysis,curve of form and position error source,contact error source and pose error is drawn.feasibility assembly area is judged using contour method,and put forward a control method of assembly geometric error.On the basis of location error model,hierarchical relation of location error is established. Design on 216 factors analysis experiment, Correlation Coefficient of location error of axis are established, and sequence of regulation is determined. The mathematical relationship of contact stiffness and the location error are established using Curvilinear Regression Analysis. At last, a kind of assembly process scheme is established, which was applied to enterprises and result of error detection meet qualified standard, so effectiveness of assembly method is verified.