Motor control device provided with feedforward control
A motor control device for controlling a motor which drives a control target, includes: a speed feedback control unit which generates a pre-correction torque command for controlling such that an actual speed of the control target follows a speed command which is input; an inverse model calculation unit which calculates a coefficient of an inverse model with a transfer function inversed from a transfer function of the control target by using the speed command and the pre-correction torque command; a torque correction value generating unit which generates a torque correction value by using the speed command and the coefficient of the inverse model; and a torque command generating unit which generates a torque command for the motor which drives the control target by using the pre-correction torque command and torque correction value.
1. A motor control device for controlling a motor which drives a control target, the motor control device comprising:
a speed feedback control unit which generates a pre-correction torque command for controlling such that an actual speed of the control target follows a speed command which is input;
an inverse model calculation unit which calculates a coefficient of an inverse model with a transfer function inversed from a transfer function of the control target by using the speed command and the pre-correction torque command;
a torque correction value generating unit which generates a torque correction value by using the speed command and the coefficient of the inverse model; and
a torque command generating unit which generates a torque command for the motor which drives the control target by using the pre-correction torque command and torque correction value.
2. The motor control device according to claim 1 , wherein the inverse model calculation unit comprises:
a coefficient correction value calculation unit which calculates a coefficient correction value by using the speed command, the pre-correction torque command, and a predetermined adaptive coefficient;
an inertia coefficient estimation value calculation unit which calculates, by using the coefficient correction value and an inertia coefficient estimation value, a new inertia coefficient estimation value;
a viscous friction coefficient estimation value calculation unit which calculates, by using the coefficient correction value and a viscous friction coefficient estimation value, a new viscous friction coefficient estimation value; and
a Coulomb friction coefficient estimation value calculation unit which calculates, by using the coefficient correction value and a Coulomb friction coefficient estimation value, a new Coulomb friction coefficient estimation value,
wherein a coefficient of the inverse model is calculated for each sampling period by using the new inertia coefficient estimation value, the new viscous friction coefficient estimation value, and the new Coulomb friction coefficient estimation value.
3. The motor control device according to claim 1 , wherein, when an absolute value of the speed command is smaller than a predetermined value, the inverse model calculation unit maintains the coefficient of the inverse model calculated in a sampling period before a sampling period in which the speed command is input, and outputs the coefficient to the torque correction value generating unit.
4. The motor control device according to claim 1 , wherein the torque correction value generating unit generates the torque correction value by adding:
a product of an acceleration calculated from the speed command and an inertia coefficient estimation value used for an estimation of inertia of the control target;
a product of the speed command and a viscous friction coefficient estimation value used for an estimation of a viscous friction coefficient of the control target; and
a product of a polarity of the speed command and a Coulomb friction coefficient estimation value used for an estimation of a Coulomb friction coefficient of the control target.