US 8,027,766 B2 · Electric power steering device

Abstract

The rotational angle correction controller includes a second correction amount-computing part that computes a second correction amount ε2 for correcting the rotational angle θ such that the phase is shifted in the steering operation direction, and the rotational angle correction controller performs the rotational angle correction by adding the computed second correction amount ε2 to the rotational angle θ. Further, the rotational angle correction controller includes a stuck steering wheel determining part that detects the significant reduction in the follow-up performance of the motor with respect to the steering operation that occurs due to the existence of the deceleration section caused by execution of the above-described electric current restriction, that is, the occurrence of the stuck steering wheel. When the occurrence of the stuck steering wheel is detected, the second correction amount-computing part changes the second correction amount ε2 to a value (ε2′) larger than the normal value.

Claims20

Dependent claims

An electric power steering device, comprising:

a steering force assisting device having a motor that functions as a drive source and providing a steering system with an assist power for assisting a steering operation;
and
a control device that controls an operation of the steering force assisting device through a supply of a drive power to the motor, the control device including:
a motor control signal output part that outputs a motor control signal;
a drive circuit that supplies the drive power of three phases to the motor on the basis of the motor control signal;
and
an abnormality-detecting part that detects an occurrence of a failure caused in the phases of the motor,
wherein:
the motor control signal output part generates the motor control signal by executing current control on the basis of a rotational angle of the motor and, when the occurrence of the failure is detected, executes output of the motor control signal by means of two electrification phases other than a phase with the failure;
and,
when the occurrence of the failure is detected, the motor control signal output part performs a correction of the rotational angle so that an angular phase is shifted in a direction of the steering operation, and the motor control signal output part increases an amount of the correction of the rotational angle as rotational angular velocity of the motor is increased.

8 more elements

An electric power steering device, comprising:

a steering force assisting device having a motor that functions as a drive source and providing a steering system with an assist power for assisting a steering operation;
a follow-up performance reduction-detecting part that detects a reduction in rotational follow-up performance of the motor with respect to the steering operation;
and
a control device that controls an operation of the steering force assisting device through a supply of a drive power to the motor, the control device including:
a motor control signal output part that outputs a motor control signal;
a drive circuit that supplies the drive power of three phases to the motor on the basis of the motor control signal;
and
an abnormality-detecting part that detects an occurrence of a failure caused in the phases of the motor,
wherein:
the motor control signal output part generates the motor control signal by executing current control on the basis of a rotational angle of the motor and, when the occurrence of the failure is detected, executes output of the motor control signal by means of two electrification phases other than a phase with the failure;
and,
when the occurrence of the failure is detected, the motor control signal output part performs a correction of the rotational angle so that an angular phase is shifted in a direction of the steering operation, and when the reduction in the rotational follow-up performance of the motor is detected, the motor control signal output part increases an amount of the correction of the rotational angle.

9 more elements

A control method of an electric power steering device which has a steering force assisting device having a motor that functions as a drive source and providing a steering system with an assist power for assisting a steering operation, and which controls an operation of the steering force assisting device through a supply of a drive power to the motor, the method comprising:

generating and outputting a motor control signal by executing current control on the basis of a rotational angle of the motor;
supplying the drive power of three phases to the motor on the basis of the motor control signal;
detecting an occurrence of a failure caused in the phases of the motor;
when the occurrence of the failure is detected, executing output of the motor control signal by means of two electrification phases other than a phase with the failure and performing a correction of the rotational angle so that an angular phase is shifted in a direction of the steering operation;
detecting a reduction in rotational follow-up performance of the motor with respect to the steering operation;
and
when the reduction in the rotational follow-up performance of the motor is detected, increasing the amount of correction of the rotational angle.

4 more elements

Dependencies are inferred from the claim text.

Electric power steering device

Life of this patent

Electric power steering device

Life of this patent

Abstract

Claims20