KR101774255B1 - Electric power steering system - Google Patents

Abstract

An electric steering system comprising a torque sensor for detecting torque information of a vehicle handle, a vehicle speed sensor for detecting a running speed of the vehicle, a steering angle sensor for detecting a steering angle of the vehicle handle, and an ECU for controlling an electric steering control operation, Wherein the MCU includes an internal timer and a time value of the internal timer, wherein the internal timer has a time value of at least < RTI ID = 0.0 > The malfunction of the internal timer of the MCU can be prevented in advance and the abnormal operation of the EPS can be prevented by previously preventing the malfunction of the internal timer of the MCU due to the malfunction of the internal timer .

Description

[0001] ELECTRIC POWER STEERING SYSTEM [0002]

The present invention relates to an electric steering system capable of detecting an internal timer failure of an MCU used in an ECU of an electric steering system.

Generally, a vehicle is equipped with an electronic control unit (hereinafter referred to as ECU) for receiving an electric signal detected by various input sensors and outputting a digital control signal for driving various actuators on the output side have.

The steering system for increasing or decreasing the operating force of the steering wheel according to the speed of the vehicle using such an ECU includes an electronic control power steering system for adjusting the assist amount by adding an electronic control valve for adjusting the hydraulic pressure in the existing hydraulic steering system, And an electric power steering (EPS) system that adjusts an assist amount by driving a motor.

In this EPS system, when the driver operates the handle, the gear linked to the handle rotates, and when the torque signal detected by the torque sensor interlocked with the gear is transmitted to the ECU, the ECU appropriately controls the current supplied to the EPS motor EPS motor, and the EPS motor outputs an appropriate auxiliary steering force to facilitate the operation of the driver's steering wheel.

A microcontroller unit (hereinafter referred to as an MCU) used in an electronic control unit (hereinafter, referred to as 'ECU') of the EPS system uses an internal timer to calculate the cycle of the steering angle sensor and the PWM signal Lt; / RTI > In addition, the MCU accepts the torque value of the torque sensor in real time using DMA (Direct Memory Access). At this time, the MCU uses an internal timer.

In the ECU of the EPS system, a main MCU for controlling the overall operation of the system and a sub MCU for monitoring the operation of the main MCU in order to detect a failure (failure) of the main MCU are provided.

Generally, if a malfunction occurs in the MCU, the malfunction is notified to the driver by detecting the failure, but if the MCU's internal timer fails or malfunctions due to abnormal operation, There is a risk that the malfunction of the EPS (e.g., loss of steering force due to oscillation of the steering wheel and fixed torque value, loss of handle restoring force, etc.) may occur.

This paper proposes an electric steering system that can prevent the abnormal operation of EPS by preventing the danger that may be caused by malfunction or malfunction of internal timer of MCU.

We also propose an electric steering system that can enhance the safety aspect of EPS and improve the reliability of MCU operation.

To this end, an electric steering system according to an aspect of the present invention includes a torque sensor for detecting torque information of a vehicle handle, a vehicle speed sensor for detecting a running speed of the vehicle, a steering angle sensor for detecting a steering angle of the vehicle handle, Wherein the ECU includes an MCU for generating a motor drive signal for reducing an operation force of a driver's handle based on information detected from a torque sensor, a vehicle speed sensor, and a steering angle sensor, and the MCU includes: Includes an internal timer and a failure determination unit for detecting a failure or malfunction of the internal timer based on the periodic characteristics of the time value of the internal timer.

The MCU further includes a first buffer for storing a time value of an internal timer at the time of receiving the torque information or the steering angle information; And a second buffer for storing the time value of the internal timer at the time of receiving the torque information or the steering angle information in the next control cycle.

The failure determination unit compares the time value of the internal timer stored in the first buffer with the time value of the internal timer stored in the second buffer, and detects whether a failure of the internal timer occurs according to the comparison result.

If the time value of the internal timer stored in the first buffer and the time value of the internal timer stored in the second buffer are equal to each other or the change of the time value is out of the preset rule, the failure determining unit determines that a failure occurs in the internal timer of the MCU do.

Further, if it is determined that a failure occurs in the internal timer, the MCU notifies the driver of the failure of the internal timer through a warning message or a warning sound or controls the steering control to be stopped.

According to the proposed electric-powered steering system, a malfunction or malfunction of the internal timer is detected based on the periodic characteristic of the time value of the internal timer of the MCU, and the result of the detection is notified to the driver or the control operation is stopped, The abnormal operation of the EPS can be prevented by preventing the occurrence of the malfunction or malfunction of the EPS.

1 is a control block diagram of an electric steering system according to an embodiment of the present invention.
2 is a flowchart of a method of controlling an electric steering system according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

The present invention relates to an electric steering system and a control method thereof capable of detecting an internal timer failure of an MCU used in an electric power steering system of an electric power steering system and a control method thereof, The present invention provides an electric steering system and a control method thereof that can prevent an abnormal operation of an EPS.

1 is a control block diagram of an electric steering system according to an embodiment of the present invention.

1, an electric steering system according to an embodiment of the present invention includes a torque sensor 110, a vehicle speed sensor 120, a steering angle sensor 130, an ECU 140, a drive circuit 170, (180).

The torque sensor 110 detects the torque information of the vehicle handle and transmits the torque information of the detected vehicle handle to the ECU 140. [

The vehicle speed sensor 120 detects the running speed of the vehicle and transmits the detected running speed information of the vehicle to the ECU 140. [

The steering angle sensor 130 detects the steering angle of the vehicle handle and transmits the steering angle information of the detected vehicle handle to the ECU 140. [

The ECU 140 is for controlling the overall operation of the electric steering system, and the ECU 140 includes the interface unit 150 and the MCU 160 again.

The interface unit 150 transmits the information detected through the torque sensor 110, the vehicle speed sensor 120 and the steering angle sensor 130 to the MCU 160 in the ECU 140.

The MCU 160 receives the vehicle state information of the torque detected by the torque sensor 110, the vehicle speed sensor 120 and the steering angle sensor 130, the traveling speed of the vehicle, and the steering angle, And outputs the generated motor driving signal to the driving circuit unit 170. A failure determination unit 164, a first buffer 166 and a second buffer 168 are provided in the MCU 160 to detect whether the internal timer 162 or the internal timer 162 has failed .

The internal timer 162 is used by the MCU 160 to receive the period of the steering angle sensor 130 and the duty value of the PWM signal. In addition, the MCU 160 receives the torque information detected from the torque sensor 110 in real time using a DMA (not shown). The internal timer 162 of the MCU 160 is used to receive the torque information in real time. The time value output from the internal timer 162 of the MCU 160 increases or decreases with a constant period.

The failure determination unit 164 is a unit for detecting whether or not the internal timer 162 has failed (failure). The failure determination unit 164 determines whether or not the internal timer 162 at the time when the MCU 160 receives the torque information or the steering angle information (162) in the first buffer (166). The failure determination unit 164 stores the time value of the internal timer 162 at the time when the MCU 160 receives the torque information or the steering angle information in the second buffer 168 in the next control cycle. The failure determination unit 164 compares the time value of the internal timer 162 stored in the first buffer 166 with the time value of the internal timer 162 stored in the second buffer 168, (Failure) of the internal timer 162 is detected. Since the time value output from the internal timer 162 increases or decreases with a constant period, the time value in the previous control cycle and the time value in the current control cycle differ from each other based on a constant value. The failure determination unit 164 determines whether the time value of the internal timer 162 stored in the first buffer 166 is equal to the time value of the internal timer 162 stored in the second buffer 168, (For example, a difference of 90% occurs between a time value stored in the first buffer and a time value stored in the second buffer), a failure occurs in the internal timer 162 of the MCU 160 . When a failure (failure) of the internal timer 162 of the MCU 160 is detected, the MCU 160 notifies the driver of the failure of the internal timer 162 through a warning message (warning lamp) or a warning sound or performs a steering control Stop.

The driving circuit unit 170 applies the assist current according to the motor driving signal output from the MCU 160 to the motor 180 to drive the motor 180 to generate the steering assist force.

2 is a flowchart of a method of controlling an electric steering system according to an embodiment of the present invention.

First, when the vehicle starts running, the failure determination unit 164 in the MCU 160 of the ECU 140 obtains the time value of the internal timer 162 at the time when the MCU 160 receives the torque information or the steering angle information (210).

Thereafter, the failure determining unit 164 obtains the time value of the internal timer 162 at the time when the MCU 160 receives the torque information and the steering angle information again, and uses the time value of the internal timer to calculate the internal timer 162 (220). The operation 210-220 is repeated one more time to check the cycle of the internal timer 162 of the MCU 160 twice.

Next, the failure determination unit 164 determines whether the cycle of the internal timer 162, that is, the previous cycle, and the cycle of the internal timer 162, which are checked later, are equal to each other (230).

The MCU 160 determines that the reliability of the internal timer 162 is high and returns to the operation 210. If it is determined that the current cycle of the internal timer 162 is the same as the current cycle of the internal timer 162 do.

If it is determined that the previous cycle and the current cycle of the internal timer 162 are not equal to each other (NO in operation 230), the failure determination unit 164 determines whether the MCU 160 has received the torque information or the steering angle information And stores the time value of the internal timer 162 at the time of receiving the first timer 166 in the first buffer 166 (240).

The failure determination unit 164 stores the time value of the internal timer 162 at the time when the MCU 160 receives the torque information and the steering angle information in the second buffer 168 in the next control cycle.

Next, the failure determination unit 164 determines whether the time value of the internal timer 162 stored in the first buffer 166 is the same as the time value of the internal timer 162 stored in the second buffer 168 (260).

If it is determined that the time value of the internal timer 162 stored in the first buffer 166 and the time value of the internal timer 162 stored in the second buffer 168 are equal to each other (YES in operation 260) The failure determination unit 164 determines that a failure has occurred in the internal timer 162 of the MCU 160. [ When a failure (failure) of the internal timer 162 of the MCU 160 is detected, the MCU 160 notifies the driver of the failure of the internal timer 162 through a warning message (warning lamp) or a warning sound or performs a steering control (270).

If it is determined that the time value of the internal timer 162 stored in the first buffer 166 and the time value of the internal timer 162 stored in the second buffer 168 are not equal to each other, The failure determination unit 164 determines whether the change of the time value deviates from a predetermined rule (for example, a difference of 90% occurs between the time value stored in the first buffer and the time value stored in the second buffer) (280).

As a result of the determination, if it is determined that the change of the time value deviates from the predetermined rule (Yes in operation 280), the failure determination unit 164 determines that a failure has occurred in the internal timer 162 of the MCU 160. Accordingly, the MCU 160 notifies the driver of the failure of the internal timer 162 through a warning message (warning lamp) or a warning sound or controls the steering control to stop (270).

On the other hand, if it is determined that the change of the time value does not deviate from the predetermined rule ('No' in operation 280), the failure determination unit 164 determines that the internal timer 162 of the MCU 160 is performing a normal operation . Thus, the MCU 160 returns to operation 210.

110: torque sensor 120: vehicle speed sensor
130: steering angle sensor 140: ECU
150: interface unit 160: MCU
162: Internal timer 164: Fault determination unit
166: first buffer 168: second buffer
170: driving circuit part 180: motor

Claims (5)

1. An electric steering system comprising a torque sensor for detecting torque information of a vehicle handle, a vehicle speed sensor for detecting a traveling speed of the vehicle, a steering angle sensor for detecting steering angle information of a vehicle handle, and an ECU for controlling an electric steering control operation,
Wherein the ECU includes an MCU for generating a motor drive signal for reducing an operation force of a driver's handle based on information detected from the torque sensor, the vehicle speed sensor, and the steering angle sensor,
The MCU includes a first buffer for storing an internal timer, a time value of the internal timer at the time of receiving the torque information and the steering angle information, and a second buffer for storing the torque information and the steering angle information at the next control period A second buffer for storing a time value of the internal timer in the internal timer; and a failure determination unit for detecting a failure or malfunction of the internal timer based on a periodic characteristic of the time value of the internal timer. delete The method according to claim 1,
Wherein the failure determination unit compares a time value of an internal timer stored in the first buffer with a time value of an internal timer stored in the second buffer and detects whether a failure has occurred in the internal timer according to the comparison result. The method of claim 3,
Wherein the failure determination unit determines whether the time value of the internal timer stored in the first buffer is equal to the time value of the internal timer stored in the second buffer or if the change in the time value is out of a preset rule, An electric steering system that determines that a fault has occurred. 5. The method of claim 4,
Wherein the MCU notifies the driver of a failure of the internal timer through a warning message or a warning sound or to stop the steering control if it is determined that a failure has occurred in the internal timer.

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