US-12623715-B2 - Electric power steering device

US12623715B2US 12623715 B2US12623715 B2US 12623715B2US-12623715-B2

Abstract

A first motor control measure sends a first command to a second motor control measure in order to conduct drive control of a motor when conducting steering assist control, and assists drive of the motor by conducting drive control of the motor based on a second command sent from the second motor control measure to conduct drive control of the motor when conducting the steering assist control, and the second motor control measure sends the second command to the first motor control measure when conducting autonomous drive assist control, and assists drive of the motor by conducting drive control of the motor based on the first command to conduct the steering assist control.

Inventors

Chiaki Fujimoto

Assignees

MITSUBISHI ELECTRIC CORPORATION

Dates

Publication Date: 20260512
Application Date: 20211214

Claims (12)

1 . An electric power steering device comprising: a vehicle condition sensor that detects vehicle condition of a vehicle, and detects information from outside the vehicle; an autonomous drive assist controller that generates a steering angle command of a steering of the vehicle based on a detection result of the vehicle condition sensor; a torque sensor that detects a steering torque of the steering; a motor that is rotated to obtain the steering angle of the steering; a first motor controller that conducts steering assist control to assist steering of the motor based on detection results of the torque sensor, and a second motor controller that conducts autonomous drive assist control that conducts autonomous steering of the steering by drive control of the motor, according to the steering angle command, wherein: the first motor controller sends a first command to the second motor controller in order to conduct drive control of the motor when conducting the steering assist control, and assists drive of the motor by drive control of the motor based on a second command sent from the second motor controller to conduct drive control of the motor when conducting the steering assist control, and the second motor controller sends the second command to the first motor controller when conducting the autonomous drive assist control, and assists drive of the motor by drive control of the motor based on the first command to conduct the steering assist control.
2 . The electric power steering device according to claim 1 , wherein: the first motor controller calculates a target steering angle which is a target value of a steering angle, and sends the calculated target steering angle as the first command to the second motor controller, when conducting the steering assist control, and the second motor controller calculates a steering angle torque command based on a variance between the steering angle command and a detected steering angle value, as a target value of a motor torque, and sends the calculated steering angle torque command as the second command to the first motor controller when conducting the autonomous drive assist control.
3 . The electric power steering device according to claim 2 , wherein: drive control of the motor is continued only by the second motor controller in a case where the first motor controller is not able to conduct drive control of the motor due to an abnormality when conducting the steering assist control, and drive control of the motor is continued only by the first motor controller when the second motor controller is not able to conduct drive of the motor due to an abnormality when conducting the autonomous drive assist control.
4 . The electric power steering device according to claim 2 , wherein: the second motor controller stops drive control of the motor in a case where it is not possible to receive the first command from the first motor controller when conducting the steering assist control, and the first motor controller calculates a torque target value to obtain the steering angle based on a variance between the steering angle command output from the autonomous drive assist controller and a detected rotation angle of the motor, and conducts drive control of the motor based on the calculated torque target value, in a case where it is not possible to receive the second command from the second motor controller when conducting the autonomous drive assist control.
5 . The electric power steering device according to claim 1 , wherein: the first motor controller sends a first variance which is a variance between a rotation angle of the motor made to be a target and a detected rotation angle of the motor, as the first command to the second motor controller when conducting the steering assist control, and the second motor controller converts the steering angle command to a rotation angle of the motor, drives the motor based on a second variance which is a variance between the converted rotation angle of the motor and a detected rotation angle of the motor, while calculating a steering angle torque command which is a target value of a torque to obtain the steering angle based on the second variance, and sends the steering angle torque command to the first motor controller as the second command when conducting the autonomous drive assist control.
6 . The electric power steering device according to claim 5 , wherein: drive control of the motor is continued only by the second motor controller in a case where the first motor controller is not able to conduct drive control of the motor due to an abnormality when conducting the steering assist control, and drive control of the motor is continued only by the first motor controller when the second motor controller is not able to conduct drive of the motor due to an abnormality when conducting the autonomous drive assist control.
7 . The electric power steering device according to claim 5 , wherein: the second motor controller stops drive control of the motor in a case where it is not possible to receive the first command from the first motor controller when conducting the steering assist control, and the first motor controller calculates a torque target value to obtain the steering angle based on a variance between the steering angle command output from the autonomous drive assist controller and a detected rotation angle of the motor, and conducts drive control of the motor based on the calculated torque target value, in a case where it is not possible to receive the second command from the second motor controller when conducting the autonomous drive assist control.
8 . The electric power steering device according to claim 1 , wherein: the first motor controller calculates a first target voltage which is a voltage target value to drive the motor, and sends the calculated first target voltage as the first command to the second motor controller when conducting the steering assist control, and the second motor controller calculates a second voltage target value which is a target voltage to drive the motor, and sends the calculated second target voltage as the second command to the first motor controller when conducting the autonomous drive assist control.
9 . The electric power steering device according to claim 8 , wherein: drive control of the motor is continued only by the second motor controller in a case where the first motor controller is not able to conduct drive control of the motor due to an abnormality when conducting the steering assist control, and drive control of the motor is continued only by the first motor controller when the second motor controller is not able to conduct drive of the motor due to an abnormality when conducting the autonomous drive assist control.
10 . The electric power steering device according to claim 8 , wherein: the second motor controller stops drive control of the motor in a case where it is not possible to receive the first command from the first motor controller when conducting the steering assist control, and the first motor controller calculates a torque target value to obtain the steering angle based on a variance between the steering angle command output from the autonomous drive assist controller and a detected rotation angle of the motor, and conducts drive control of the motor based on the calculated torque target value, in a case where it is not possible to receive the second command from the second motor controller when conducting the autonomous drive assist control.
11 . The electric power steering device according to claim 1 , wherein: drive control of the motor is continued only by the second motor controller in a case where the first motor controller is not able to conduct drive control of the motor due to an abnormality when conducting the steering assist control, and drive control of the motor is continued only by the first motor controller when the second motor controller is not able to conduct drive of the motor due to an abnormality when conducting the autonomous drive assist control.
12 . The electric power steering device according to claim 1 , wherein: the second motor controller stops drive control of the motor in a case where it is not possible to receive the first command from the first motor controller when conducting the steering assist control, and the first motor controller calculates a torque target value to obtain the steering angle based on a variance between the steering angle command output from the autonomous drive assist controller and a detected rotation angle of the motor, and conducts drive control of the motor based on the calculated torque target value, in a case where it is not possible to receive the second command from the second motor controller when conducting the autonomous drive assist control.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a National Stage of International Application No. PCT/JP2021/045999 filed Dec. 14, 2021. TECHNICAL FIELD The present disclosure relates to an electric power steering device. BACKGROUND ART Conventionally, an electric power steering device that conducts steering assist control as well as autonomous drive assist control is known as an electric power steering device that assists steering of a motor drive (refer to Patent Document 1). The steering assist control is a control that supplies steering assist torque from a motor driving force when assisting a vehicle operator in steering operations. Autonomous drive assist control is a control where a course of direction of a vehicle is changed by changing a steering angle regardless of the vehicle operator steering (for example, a parking-assist system or a route-follow control or the like). CITATION LIST Patent Document [Patent Document 1] Japanese Unexamined Patent Application, First Publication 2012-56404 SUMMARY OF INVENTION Problem to be Solved by Invention In Patent Document 1, a first motor control circuit that conducts steering assist control, and a second motor control circuit that conducts autonomous drive assist control are configured independently from one another. Thus, there are cases where it is not possible to maintain steering assist when an abnormality occurs during steering assist control due to a first motor control circuit, and it is not possible to maintain autonomous drive assist when an abnormality occurs during autonomous drive assist control due to a second motor control circuit. The present disclosure has been made in order to address the problem above, and an object is to provide an electric power steering device that maintains steering assist even when an abnormality occurs during steering assist control, and that maintains autonomous drive assist control even when an abnormality occurs during autonomous control. Means to Solve the Problem An electric power steering device according to an embodiment of the present disclosure includes a vehicle condition sensor that detects vehicle condition of a vehicle, and detects information outside to the vehicle; an autonomous drive assist controller that generates a steering angle command of a steering of the vehicle based on detection results of the vehicle condition sensor; a torque sensor that detects a steering torque of the steering; a motor that is rotated to obtain the steering angle of the steering; a first motor controller that conducts steering assist control to assist steering of the motor based on detection results of the torque sensor, and a second motor controller that conducts autonomous drive assist control that conducts autonomous steering of the steering by drive control of the motor, according to the steering angle command, wherein: the first motor controller sends a first command to the second motor controller in order to conduct drive control of the motor when conducting the steering assist control, and assists drive of the motor by drive control of the motor based on a second command sent from the second motor controller to conduct drive control of the motor when conducting the steering assist control, and the second motor controller sends the second command to the first motor controller when conducting the autonomous drive assist control, and assists drive of the motor by drive control of the motor based on the first command to conduct the steering assist control. Effects of the Invention As explained above, according to the present disclosure, it is possible to maintain steering assist even when an abnormality occurs during steering assist control, and to maintain autonomous drive assist control even when an abnormality occurs during autonomous control. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 A diagram of a vehicle steering system equipped with an electric power steering device according to a first embodiment. FIG. 2 A block diagram of a motor control according to the first embodiment. FIG. 3 A schematic outline diagram of a motor drive unit and a motor drive unit according to the first embodiment. FIG. 4 A view that explains a map of vehicle speed and steering torque according to the first embodiment. FIG. 5 A view that explains a generation method of steering assist angle command according to the first embodiment. FIG. 6 A block view of a current control unit according to the first embodiment. FIG. 7 A block view of a steering angle command unit according to the first embodiment. FIG. 8 A block view of a motor angle control unit according to the first embodiment. FIG. 9 A diagram of the vehicle steering system equipped with an electric power steering device according to a second embodiment. FIG. 10 A block diagram of the motor control according to the second embodiment. FIG. 11 A diagram of the vehicle steering system equipped with an electric power steering device according to a third embodiment. FIG. 12 A block di