Image Number 5 for United States Patent #5310983.
A feed rate control device for controlling the feeding operation of the electrode of a computerized numerical control type electric spark machine is equipped with an amplitude limiter, a regulator, and a proportional-plus-integral compensator. The amplitude limiter is capable of automatically limiting the amplitude of the input signal according to the moving situation of the electrode of the electric spark machine. By using of the amplitude limiter, the sensitivity of the system may be limited to a suitable level and therefore the stability of the whole system is increased. The proportional-plus-integral compensator is used to compensate the steady state error caused by improper low resolution when the output signal of the amplitude limiter is below an preliminary level. The regulator is used for facilitating the adjustment of the sensitivity of the system according to user's practical experiences.