Research On Processing Stability Online Detecting And Optimizing Control Of Complex Manufacturing System

With the demand of high machining quality in advanced manufacturing field, fault identification and control become the highlighted important technology in machining, and online chatter detecting of milling stability is one of the research contents. Take TDNC-H8 CNC machine as the verification platform, the instability quick forecast theory and stability online optimizing control was researched, the integration settlement scheme of stability online detecting was studied to make sure the chatter free as well as high precision and efficiency.Based on the nonlinear control theory in discrete dynamic system, the C-C algorithm was used to determine appropriate embedding dimension and time delay. The coarse grained entropy rate feature was extracted to reflect the predictable rule in chatter. Through the validation experimenst, the CER can be applied in instability forecast quickly and precisely.Considering the effect of multi-degree and time-varying milling force coefficients, the milling stability prediction theory in thick-wall milling process was studied. Based on the milling force model with time-varying milling force coefficients, the thick-wall milling stability dynamic model was discussed, which lead to the three dimension stability lobe chart with multi-degree coupling and time-varying milling force coefficients. By analyzing the stability state with milling parameters of n, ap, ae , fz as well as milling validate experiment, the stablity prediction theory which is sutiable to thick-wall milling was setup.Based on the time-varying milling force coefficients stability prediction theory, the stability of tool-workpiece system considering stiffness time-varying in thin-walled milling was studied. By modeling the tool-workpiece coupling system transfer function, the online real-time acquisition of transfer function method using spindle frequency sweeping of operational modal was discussed, the chatter prediction theory with high precision and real-time was setup.Taking the instability forecast theory for chatter detecting and by considering maximum materials removal rate (MRR) of production planning and machining stage, the online optimizing control method was studied. In production planning stage, the structure parameters to enlarge stability zone and the MRR acquisition method in machining stage were discussed, and the solution to enlarge stability zone and fast searching online optimizing control was implemented.Based on network, the modularization embedded online detecting system with the characteristic of reconfiguration and open system architecture was studied. Focused on the author's main work of software programming, the software design methods were discussed. The online detecting experiment validation platform can be used by programming several kinds of algorithms, which takes the foundation of engineering application to the chatter online detecting and control theory.