抄録
The actual circle radius decreases remarkably for high feed rates of NC machine tools during circular interpolation motion. This decreasing error ΔR is caused by delay factors inherent in the NC servo control system, expressed by the equation ΔR=(Ts2+Tp2)F2/2R, where R is the circle radius, Ts is the time constant of the smoothing loop, Tp is the time constant of the positon loop, and F is the feed rate. A feed forward control method that changes the interpolation vectors, and therefore is consistent with the conventional NC system, was developed to compensating for this error. The results show that the error was decreased in magnitude to one tenth of ΔR by this method when the feed rate was kept constant. The feed rate can be increased three times before the same error of ΔR appears.
