METHOD FOR CONTROLLING SERVOMOTOR

摘要

While the motor travels by a distance (a) after the sign of a move command is inverted (S1 and S2), a first offset amount Vmo is added to the speed command in order to accelerate the inversion of the sign of the integral value of the speed loop (S5 to S8 and S12 to S15). Thus the travelling direction of the motor is reversed more quickly. Subsequently, after the motor travels by a distance (b), a second offset value Vto is added to the speed command, and the motor produces a torque large enough to drive the table against the friction (S9, S10, and S12 to S15). The first offset amount is determined by the value of an integrator for the speed loop when the move command is inverted. The reverse movement of the motor is thus set precisely. The second offset value is determined by the acceleration of the reversing of the motor so that it can be an optimum for overcoming the friction. Since the delay is small at the time of the motor reverse, it is possible to minimize projections that appear when a quadrant changes during circular cutting.