Motor control device

1. A power steering system comprising:

an electric motor;

an output shaft driven by the electric motor;

a rack and pinion steering operation mechanism that controls steering of vehicle wheels, the output shaft being mechanically coupled to the rack and pinion steering operation mechanism;

a motor control device that performs drive control on the electric motor for steering angle control, the motor control device comprising:

a manual steering command value generation unit that generates a manual steering command value using steering torque;

an integrated angle command value computation unit that computes an integrated angle command value by adding the manual steering command value to an automatic steering command value; and

a control unit that performs the steering angle control on the electric motor on the basis of the integrated angle command value, wherein

the control unit includes

a basic torque command value computation unit that computes a basic torque command value on the basis of the integrated angle command value,

a disturbance torque estimation unit that estimates disturbance torque other than motor torque that is generated by the electric motor and acts on the output shaft, the disturbance torque including at least the steering torque, road surface load torque, and friction torque, and

a disturbance torque compensation unit that corrects the basic torque command value in accordance with the disturbance torque.

2. The power steering system according to claim 1 , wherein

the manual steering command value generation unit is configured to generate the manual steering command value using the steering torque and a spring constant and a viscous damping coefficient for generating the road surface load torque.

3. The power steering system according to claim 2 , wherein

the spring constant is set in accordance with the disturbance torque that is estimated by the disturbance torque estimation unit, and the viscous damping coefficient is set in advance to a predetermined value.

4. The power steering system according to claim 2 , wherein

the spring constant and the viscous damping coefficient are set in accordance with the disturbance torque that is estimated by the disturbance torque estimation unit.

5. The power steering system according to claim 1 , wherein:

the disturbance torque estimation unit is configured to re-estimate the disturbance torque and estimate a rotational angle of the output shaft on the basis of the basic torque command value after being corrected by the disturbance torque compensation unit or the motor torque that is generated by the electric motor and a rotational angle of the electric motor; and

the basic torque command value computation unit includes

an angle deviation computation unit that computes an angle deviation that is a difference between the integrated angle command value and the rotational angle of the output shaft, and

a feedback computation unit that computes the basic torque command value by performing predetermined feedback computation on the angle deviation.

6. The power steering system according to claim 1 , wherein:

the disturbance torque estimation unit is configured to re-estimate the disturbance torque and estimate a rotational angle of the output shaft on the basis of the basic torque command value after being corrected by the disturbance torque compensation unit or the motor torque that is generated by the electric motor and a rotational angle of the electric motor; and

the basic torque command value computation unit includes

an angle deviation computation unit that computes an angle deviation that is a difference between the integrated angle command value and the rotational angle of the output shaft, and

a feedback computation unit that computes feedback control torque by performing predetermined feedback computation on the angle deviation,

a feedforward computation unit that computes feedforward control torque by multiplying a second-order differential value of the integrated angle command value by a predetermined value, and

an addition unit that computes the basic torque command value by adding the feedforward control torque to the feedback control torque.

7. The power steering system according to claim 1 , further comprising

a first weight assignment unit that performs a weight assignment process on the automatic steering command value in accordance with predetermined first information, wherein

the integrated angle command value computation unit is configured to compute the integrated angle command value by adding the manual steering command value to the automatic steering command value after the weight assignment process by the first weight assignment unit.

8. The power steering system according to claim 1 , further comprising

a weight assignment unit that performs a weight assignment process on the manual steering command value in accordance with predetermined information, wherein

the integrated angle command value computation unit is configured to compute the integrated angle command value by adding the manual steering command value after the weight assignment process by the weight assignment unit to the automatic steering command value.

9. The power steering system according to claim 1 , further comprising:

a first weight assignment unit that performs a weight assignment process on the automatic steering command value in accordance with predetermined first information; and

a second weight assignment unit that performs a weight assignment process on the manual steering command value in accordance with predetermined second information, wherein

the integrated angle command value computation unit is configured to compute the integrated angle command value by adding the manual steering command value after the weight assignment process by the second weight assignment unit to the automatic steering command value after the weight assignment process by the first weight assignment unit.

10. The power steering system according to claim 1 , wherein

the disturbance torque compensation unit corrects the basic torque command value in accordance with the disturbance torque by subtracting the disturbance torque from the basic torque command value.

11. A power steering system comprising:

an electric motor;

an output shaft driven by the electric motor;

a rack and pinion steering operation mechanism that controls steering of vehicle wheels, the output shaft being mechanically coupled to the rack and pinion steering operation mechanism;

a motor control device that performs drive control on the electric motor for steering angle control, the motor control device comprising a processor programmed to:

generate a manual steering command value using steering torque;

compute an integrated angle command value by adding the manual steering command value to an automatic steering command value;

perform the steering angle control on the electric motor on the basis of the integrated angle command value;

compute a basic torque command value on the basis of the integrated angle command value;

estimate a disturbance torque other than motor torque that is generated by the electric motor and acts on the output shaft, the disturbance torque including at least the steering torque, road surface load torque, and friction torque; and

correct the basic torque command value in accordance with the disturbance torque.