Dynamic Modeling and Control of Multi-Task Machining Centers

This research presents a new process control strategy designed for sophisticated manufacturing systems that allows for the integrated optimisation of machining operations. This new method integrates three major elements: stability analysis using the characteristic equations of the various cutting processes, a control system that utilises a feed forward control structure and feedback control, and process optimisation using model predictive control. Verification of the developed control system was done with the aid of experiments in a multi-task machining centre specifically designed with three autonomous spindle modules to facilitate advanced sensor integration. The experiments conducted reflected astonishing improvement in machining productivity, attaining position accuracy of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2 \mu \mathrm{m}$</tex> with a machining response time of 0.5 ms. Moreover, it is demonstrated that the average surface finish quality achieved was better by up to 48.9% than conventional control techniques over a wide range of cutting conditions. The system demonstrates outstanding performance over a broad spectrum of machining operations from light to heavy duty, maintaining stability and proper disturbance response. The control method under review appears to be effective in managing the problems related to multiple simultaneous processes with the salient features of high precision and better surface quality. Such capabilities make it suitable for advanced manufacturing applications which are multifunctional in nature.