Control device, electric power steering device, and control method

A control device that controls a control target including at least a motor in a steering mechanism including an input shaft to which a steering wheel steered by a steering person is connected, an output shaft connected to the input shaft via a torsion bar, and the motor connected to the output shaft, the control device comprising:

• a reaction force controller to generate an input torque input to the control target based on a torsion bar torque generated in the torsion bar and to control a reaction force transmitted from the steering wheel to the steering person;
• and
• an assist controller to generate a correction torque to correct the input torque based on an output of the control target and a nominal model;
• wherein
• the assist controller is configured or programmed such that a transfer function of the control target is constrained by a transfer function of the nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeling error between the control target and the nominal model is approximately 1;
• and
• an order of the transfer function of the nominal model is 3 or more.

A control device that controls a control target including at least a motor in a steering mechanism including an input shaft to which a steering wheel steered by a steering person is connected, an output shaft connected to the input shaft via a torsion bar, and the motor connected to the output shaft, the control device comprising:

• a reaction force controller to generate an input torque input to the control target based on a torsion bar torque generated in the torsion bar and to control a reaction force transmitted from the steering wheel to the steering person;
• and
• an assist controller to generate a correction torque to correct the input torque based on an output of the control target and a nominal model;
• wherein
• the assist controller is configured or programmed such that a transfer function of the control target is constrained by a transfer function of the nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeling error between the control target and the nominal model is approximately 1;
• and
• the nominal model is a model having a frequency characteristic between a one-inertia system and a two-inertia system.

A control method for controlling a control target including at least a motor in a steering mechanism including an input shaft to which a steering wheel steered by a steering person is connected, an output shaft connected to the input shaft via a torsion bar, and the motor connected to the output shaft, the control method comprising:

• generating an input torque input to the control target based on a torsion bar torque generated in the torsion bar and controlling a reaction force transmitted from the steering wheel to the steering person;
• and
• generating a correction torque to correct the input torque based on an output of the control target and a nominal model;
• wherein
• the generating of the correction torque includes constraining a transfer function of the control target by a transfer function of the nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeling error between the control target and the nominal model is approximately 1;
• and
• the nominal model is a model in which mechanical characteristics when the steering person steers the steering wheel are considered.

A control method for controlling a control target including at least a motor in a steering mechanism including an input shaft to which a steering wheel steered by a steering person is connected, an output shaft connected to the input shaft via a torsion bar, and the motor connected to the output shaft, the control method comprising:

• generating an input torque input to the control target based on a torsion bar torque generated in the torsion bar and controlling a reaction force transmitted from the steering wheel to the steering person;
• and
• generating a correction torque to correct the input torque based on an output of the control target and a nominal model;
• wherein
• the generating of the correction torque includes constraining a transfer function of the control target by a transfer function of the nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeling error between the control target and the nominal model is approximately 1;
• and
• an order of a transfer function of the nominal model is 3 or more.

A control method for controlling a control target including at least a motor in a steering mechanism including an input shaft to which a steering wheel steered by a steering person is connected, an output shaft connected to the input shaft via a torsion bar, and the motor connected to the output shaft, the control method comprising:

• generating an input torque input to the control target based on a torsion bar torque generated in the torsion bar and controlling a reaction force transmitted from the steering wheel to the steering person;
• and
• generating a correction torque to correct the input torque based on an output of the control target and a nominal model;
• wherein
• the generating of the correction torque includes constraining a transfer function of the control target by a transfer function of the nominal model in a frequency band where a gain in a gain characteristic of a complementary sensitivity function with respect to a modeling error between the control target and the nominal model is approximately 1;
• and
• the nominal model is a model having a frequency characteristic between a one-inertia system and a two-inertia system.