Okuma Corporation

Mitsuaki Adachi

Akihito Kataoka

A control device which controls a servo motor of a machine tool in the event of power failure is provided. The control device includes a power failure detecting unit () which monitors an input power supply () and when power failure is detected, instructs servo motor amplifiers () to decelerate and stop servo motors () while maintaining a controlled state, and instructs a spindle motor () to suspend application of electricity, an alarm threshold changing unit () which, in response to a power failure detection signal from the power failure detecting unit (), changes alarm threshold values for direct current voltage reduction abnormality of a power circuit (), the servo motor amplifiers (), and a spindle motor amplifier () from values for a normal operation to values during power failure, and a retraction operation instructing unit () which, in response to the power failure detection signal from the power failure detecting unit (), instructs servo motor amplifiers () to perform a retraction operation by a small distance which is defined in advance.

Control device for machine tool

The present invention provides a position control apparatus in which a motor output torque can be approximated to that of the maximum output torque curve of the motor by generating a position command combining constant acceleration and exponential acceleration. This position control apparatus comprises means for generating a position command so as to give constant acceleration by adding an acceleration unit quantity &Dgr;Naa, set as a parameter beforehand, to a speed unit quantity N(n), means for generating a position command by calculating an acceleration unit quantity using an exponential function expression and by adding the calculated result to the speed unit quantity N(n), and means for generating a position command by comparing the present speed unit quantity N(n) and a function change speed unit quantity Nc set as a parameter beforehand and by selecting either of the command generating means described above on the basis of the compared result.

Growing community of inventors

Aichi, Japan

Mitsuaki Adachi