Abstract: Aiming at the problem that the energy efficiency of numerical control machine tool is difficult to obtain directly, a new method combined with the recursive method with discounted measurements was presented to predict the energy efficiency of machine tool. The estimation model of the cutting power was given in view of the power balance equation of the machine tool main drive system and the additional load loss function, further taking into account the additional load loss coefficients in model could not be directly measured, the recursive method with discounted measurements was adopted to identify the additional load loss coefficients as well as estimating the cutting power. Afterwards, the energy efficiency of machine tool was calculated according to its definition. The experiment and simulation results show that the recursive method with discounted measurements has greater advantage on obtaining higher identification precision of the additional load loss coefficients than the traditional least-squares method and the efficiency of the machine tool which was obtained by using this method comes closer to the real value than other methods.

Key words: parameter identification, NC machine tools, energy consume, energy efficiency prediction