Abstract: A position control device for suppressing occurrence of stick-slip during a feed operation performed in a very low speed region is provided. Adders add an output obtained by multiplying actual speed deviation by a proportional gain, an integral component of actual speed deviation obtained by inputting actual speed deviation to an integral compensator, an output obtained by multiplying motor speed deviation by a proportional gain, and an integral component of the motor speed deviation obtained by inputting motor speed deviation to an integral compensator. The result is output as a torque feedback command. Each integral compensator has a coefficient changer capable of changing a coefficient from 0 to 1 to adjust integral gains in accordance with a speed feedforward command or a speed command. Large integral gain increases the response speed of switching from static to kinetic friction torque in a very low speed region thereby suppressing occurrence of stick-slip.

Abstract: For full-closed position control, there is provided a position control device capable of suppressing occurrence of stick-slip which occurs during a feed operation performed in a very low speed region. An adder 5 and an adder 24 add an output obtained by multiplying an actual speed deviation El by a proportional gain Pl, an integral component Tl of the actual speed deviation which is obtained by inputting the actual speed deviation El to an integral compensator 25, an output obtained by multiplying a motor speed deviation Em by a proportional gain Pm, and an integral component Tim of the motor speed deviation which is obtained by inputting the motor speed deviation Em to an integral compensator 9, and the result is output as a torque feedback command Tfb.