Three-loop positioning servo system of ultra-precision machine tool using adaptive reference modelling

The development of many advanced technology products depends entirely on its components which tolerances or dimensions need to meet the micro-or even nanotechnology range requirements. It is generally accepted that position servo controller of machine tool is the main concern in achieving the high machining precision. Nanometric-level positioning accuracy of the ultra precision machine tool is difficult to obtain, particularly with parameters uncertainties, external nonlinear disturbances. In order to compensate above disadvantages, a model reference adaptive control method was proposed to adjust the important and main position loop of the three closed-loop control system which was designed mainly for regulating mechanical transmission modules and counterbalancing internal and external disturbances. In addition, the other two close loops were built in adjusting the acceleration and velocity of the electric drive system respectively that aimed to achieve the fast and precise response and increase dynamic stiffness. The results illustrated satisfactory performances in steady state error, load capability, high rapidity and so on.