Main spindle control method

Abstract

A spindle motor control method capable of high-accuracy contour machining uses a vector control processor executing a speed loop process to obtain a torque command (Tc). Vector control is performed (S4, S7) in accordance with a magnetic flux command (.PHI.c) set at a predetermined fixed value (CF.PHI.) when a spindle motor is being driven in a contour control mode. This prevents irregularity in motor speed and motor vibration attributable to a delay of the actual magnetic flux of the spindle motor behind the magnetic flux command, thus enabling high-accuracy contour machining. In a normal speed control mode or an orientation mode for tool replacement, the vector control is effected (S4 to S6, S8) in accordance with the magnetic flux command (.PHI.c), which is obtained on the basis of the torque command (Tc), its maximum value (Tcmax), maximum magnetic flux command (.PHI.cmax) set in dependence on the rotating speed of the motor, and minimum magnetic flux (NR.PHI.cmin, OR.PHI.min).

Dependencies are inferred from the claim text.