KR20100004176A - Method and electric power steering apparatus providing fail-safe of vehicle - Google Patents

Abstract

PURPOSE: A method for controlling the fail-safe of a vehicle and an electric power steering apparatus are provided to improve the convenience because a driver does not need to steer a vehicle by directly adding the power by generating the assist current according to the selected signal. CONSTITUTION: An electric power steering apparatus is composed of a torque sensor, a motor, and an ECU(Electric Control Unit). The torque sensor generates the torque main signal and the torque sub signal. The motor generates the auxiliary power. The ECU generates the torque mean value(S210). The ECU transmits The assist current to the motor by generating the assist and The torque sensor converts the torque main signal into the limp home mode after deactivating the torque main signal if the torque mean value exceeds the first basic value and is less than the second basic value(S250). The assist current according to the torque sub signal is generated and is transmitted to the motor.

Description

Method and Electric Power Steering Apparatus Providing Fail-Safe of Vehicle

The present invention relates to a method and an electric steering apparatus for controlling a fail-safe of a vehicle. More specifically, the driver selects a signal without a failure among the torque main signal and the torque sub-signal received from the torque sensor during steering of the vehicle, switches to a mode in which the selected signal is available, and then selects the selected signal. The present invention relates to a method and an electric steering apparatus for controlling a fail-safe of a vehicle which can prevent malfunction due to steering and increase driver's convenience by generating assist current according to the present invention.

In general, as a power assist steering device of a vehicle, a hydraulic power steering device using hydraulic pressure of a hydraulic pump is used, but since the 1990s, an electric power steering device using an electric motor is gradually becoming more common. have.

Existing hydraulic steering system consumes energy at all times regardless of whether the steering wheel is rotated by the hydraulic pump driven by the engine. Energy-driven motors provide steering assistance. Therefore, when the electric steering device is used, it is possible to improve the energy efficiency of the vehicle compared to the hydraulic steering device.

The conventional electric steering apparatus providing a fail-safe function prevents a malfunction by controlling to stop the auxiliary power of the motor according to the sensor when a signal exceeding a preset reference value is generated among the signals received from the sensor unit. However, in the case of using the conventional method, since the driver is not provided with the auxiliary power according to the steering, the driver needs to directly apply a large force to the steering, so that the driver's convenience is deteriorated.

In order to solve the above-mentioned problems, the present invention, a mode in which the driver is selected from the torque main signal and the torque sub-signal received from the torque sensor in the process of steering the vehicle, the failure does not occur, and can use the selected signal The present invention provides a method and an electric steering apparatus for controlling a fail-safe of a vehicle which can prevent malfunction due to steering by generating assist current according to a selected signal after switching to the target. There is this.

To achieve the above object, the present invention provides a torque sensor for generating a torque main signal and a torque sub signal, which are electrical signals that detect relative rotational displacements of an input shaft and an output shaft according to rotation of a steering wheel. ; A motor for generating assistance power to facilitate steering; And a torque average value calculated by calculating an average of an absolute value of the sum of the torque main signal and the torque sub-signal, and failing to the torque main signal when the torque main signal exceeds a preset upper limit or is less than a preset lower limit. Fail) is generated, and it is checked whether the torque average value exceeds the first preset reference value and is less than the second preset reference value. As a result of the check, the torque average value exceeds the first reference value and the second reference value is determined. If the reference value is less than the reference value, the torque sub-signal is determined to be normal and fail-activated by applying a fail-safe to the torque main signal, and then switch to a limp home mode to activate the torque sub-signal. After generating the assist (Assist) current according to the torque sub-signal to control to transmit to the motor Fisherman (ECU: Electronic Control Unit) of a vehicle, comprising a fail-motor-driven steering system provides a method for controlling the safe.

According to another object of the present invention, (a) generating a torque average value for calculating the average of the absolute value of the sum of the torque main signal and the torque sub-signal; (b) checking whether the torque main signal exceeds a preset upper limit or is less than a preset lower limit; (c) If the check result of step (b) exceeds the upper limit value or is less than the lower limit value, a failure occurs in the torque main signal, and the torque average value exceeds the preset first reference value. Checking whether the reference value is less than the set second reference value; (d) When the torque average value exceeds the first reference value and is less than the second reference value as a result of the checking in step (c), it is determined that the torque sub-signal is normal and fail-safe to the torque main signal. -Safe) to deactivate; And (e) activating the torque sub-signal by switching to a limp home mode and generating an assist current according to the torque sub-signal and transmitting the generated assist current to the motor. Provides a way to control safe

As described above, according to the present invention, the driver selects a signal in which a failure does not occur among the torque main signal and the torque sub-signal received from the torque sensor in the process of steering the vehicle, and uses the selected signal. By generating the assist current according to the selected signal after switching, it is possible to prevent the malfunction due to steering, and the convenience of the driver is increased.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a block diagram schematically illustrating an electric steering apparatus for controlling a fail-safe of a vehicle according to an exemplary embodiment of the present invention.

The electric steering apparatus providing the fail-safe function according to the first and second embodiments of the present invention includes a sensor unit 110, an electronic control unit (ECU) 120, and a motor 130. It is configured by.

The sensor unit 110 includes a torque sensor 112, a vehicle speed sensor 114, and a steering angle sensor 116.

In the present invention, the sensor unit 110 is described as including only the torque sensor 112, the vehicle speed sensor 114 and the steering angle sensor 116, which is merely illustrative of the technical idea of the present invention, the present invention Those skilled in the art may variously modify and modify the components included in the sensor unit 110 without departing from the essential characteristics of the present invention.

The torque sensor 112 detects a relative rotational displacement of the input shaft and the output shaft according to the rotation of the steering wheel to generate an electrical signal and transmit the electrical signal to the electronic controller 120. In the present invention, for convenience of description, it is assumed that the electrical signal generated by the torque sensor 112 is assumed to be a torque main signal and a torque sub signal.

Here, the torque main signal and the torque sub-signal are concepts of a signal obtained by dividing an electrical signal that detects relative rotational displacement of an input shaft and an output shaft according to rotation of a steering wheel in terms of securing stability.

The vehicle speed sensor 114 detects a vehicle speed of the vehicle, generates an electrical signal proportional to the detected vehicle speed, and transmits the generated electrical signal to the electronic controller 120. In the present invention, for convenience of description, it is assumed that the electric signal generated by the vehicle speed sensor 114 is assumed to be a vehicle speed signal.

The steering angle sensor 116 generates a signal measuring the rotation angle of the steering wheel that is rotated by the driver's operation and transmits the signal to the electronic controller 120. In the present invention, for convenience of description, a signal obtained by measuring a rotation angle of a steering wheel in the steering angle sensor 116 will be described as a steering angle signal.

The electronic controller 120 receives various signals from the sensor unit 110 to determine the driving state of the vehicle and then controls the driving of the motor 130 by adjusting the amount of current flowing through the motor 130.

The electronic control unit 120 according to an embodiment of the present invention generates a torque average value calculated by calculating an average of an absolute value of the sum of the torque main signal received from the torque sensor 112 and the torque sub-signal. If the preset upper limit value is exceeded or if the preset lower limit value is exceeded, a failure occurs in the torque main signal, and if the torque average value exceeds the preset first reference value and is less than the preset second reference value, confirm and confirm As a result, when the torque average value exceeds the first reference value and is less than the second reference value, it is determined that the torque sub signal is normal, and it is deactivated by applying a fail-safe to the torque main signal, and then the limp home mode. ) To activate the torque sub-signal and then generate an assist current according to the torque sub-signal and transmit it to the motor 130. To perform.

In addition, the electronic control unit 120 according to the embodiment of the present invention controls to transmit the reduced assist current reduced by the amount of the preset current from the assist current to the motor 130 in order to minimize the malfunction caused by the abnormal occurrence of the torque sub-signal. It performs the function.

The motor 130 performs a function of generating auxiliary power for smooth steering.

2 is a flowchart illustrating a method of checking whether a torque main signal is failed according to an exemplary embodiment of the present invention.

The electronic controller 120 receives the torque main signal and the torque sub signal received from the torque sensor 112.

The electronic controller 120 generates a torque average value obtained by calculating an average of an absolute value of the sum of the torque main signal received from the torque sensor 112 and the torque sub-signal (S210).

The electronic controller 120 checks whether the torque main signal exceeds the preset upper limit or is less than the predetermined lower limit (S220).

As a result of the checking in step S220, when the torque main signal exceeds the preset upper limit value or is less than the predetermined lower limit value, the electronic controller 120 considers that a failure occurs in the torque main signal, and the torque average value is the preset first reference value. Check whether or not exceeding and less than the second preset reference value (S230).

For example, when the torque main signal exceeds the preset upper limit value or is less than the preset lower limit value, the electronic controller 120 considers that the disconnection or short circuit occurs in the torque sensor 112 to cause the torque main signal to fail.

As a result of the checking in step S230, when the torque average value exceeds the preset first reference value and is less than the preset second reference value, the electronic controller 120 determines that the torque sub signal is normal and fail-safe to the torque main signal. Deactivate by applying) (S240).

For example, when the torque average value exceeds the preset first reference value and is less than the preset second reference value, the electronic controller 120 may fail the torque main signal, but the torque sub signal may be normal because the torque average value is in an appropriate range. Will be judged.

The electronic controller 120 switches to the lymphatic home mode (S250).

3 is a flowchart illustrating a method of driving a motor according to a torque sub-signal according to an exemplary embodiment of the present invention.

The electronic controller 120 operates the lymph home mode (S310).

The electronic controller 120 activates the torque sub-signal received from the torque sensor 112 and generates an assist current according to the torque sub-signal (S320).

That is, since the electronic controller 120 is deactivated due to a failure in the torque main signal, the electronic controller 120 generates an assist current according to the torque sub signal after activating the torque sub signal determined to be normal.

The electronic controller 120 transmits a reduced assist current to the motor 130 in which the assist current is reduced by a predetermined amount of current in order to minimize the malfunction caused by the abnormal occurrence of the torque sub-signal (S330).

4 and 5 are exemplary views according to an embodiment of the present invention.

As shown in FIG. 4, the torque main signal and the torque sub-signal received from the torque sensor 112 may be in the form of a cross, and the electronic controller 120 may correspond to the torque main signal as shown in FIG. 4. It is possible to generate a torque average value for calculating the average of the absolute value of the sum of the torque sub-signals.

When the electronic control unit 120 stops the assist current to prevent a malfunction in the event of a failure even in one of the torque main signal or the torque sub signal, the driver is not provided with the auxiliary power according to the steering. It is inconvenient to steer by applying great force directly. Therefore, the electronic controller 120 can generate an assist current by using a signal in which a fail does not occur among the torque main signal or the torque sub signal.

However, when a failure occurs in the torque main signal, when switching to a mode that simply controls to use the torque sub signal, it is possible to provide auxiliary power according to the driver's steering, but at the time of switching, the torque sub signal also fails. In this case, malfunction may occur.

Therefore, it is determined whether the torque main signal and the torque sub signal are failed.

As illustrated in FIG. 5, when the torque main signal exceeds the preset upper limit value or is less than the preset lower limit value, the electronic controller 120 considers that a failure occurs in the torque main signal.

In addition, as shown in FIG. 5, when the electronic controller 120 considers that a failure occurs in the torque main signal, the torque average value is set to a first reference value (0.5 V) to determine whether the torque average value is abnormal. ) Is greater than and less than the preset second reference value (4.5 V).

As illustrated in FIG. 5, when the torque average value exceeds the preset first reference value (0.5 V) and below the preset second reference value (4.5 V), the electronic controller 120 determines that the torque sub-signal is normal.

For example, when the torque average value exceeds the preset first reference value and is less than the preset second reference value, the electronic controller 120 may fail the torque main signal, but the torque sub signal may be normal because the torque average value is in an appropriate range. Will be judged.

As shown in FIG. 5, the electronic controller 120 deactivates the torque main signal by applying fail-safe, and then switches to the lymph home mode to activate the torque sub signal determined to be normal, and then the torque sub signal. The assist current is generated according to the signal and transmitted to the motor 130.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

1 is a block diagram schematically showing an electric steering apparatus for controlling a fail-safe of a vehicle according to an embodiment of the present invention;

2 is a flowchart illustrating a method of checking whether a torque main signal is failed according to an embodiment of the present invention;

3 is a flowchart illustrating a method of driving a motor according to a torque sub-signal according to an embodiment of the present invention;

4 and 5 are exemplary views according to an embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

110: sensor unit 120: electronic control unit

130: motor

Claims (3)

A torque sensor for generating a torque main signal and a torque sub signal, which are electrical signals that detect relative rotational displacements of the input shaft and the output shaft according to the rotation of the steering wheel; A motor for generating assistance power to facilitate steering; And A torque average value is calculated by calculating an average of an absolute value of the sum of the torque main signal and the torque sub-signal. When the torque main signal exceeds a preset upper limit or is less than a preset lower limit, the torque main signal fails. ) Is considered to have occurred, and it is checked whether the torque average value exceeds a first preset reference value and is less than a second preset reference value. As a result of the check, the torque average value exceeds the first reference value and the second reference value is determined. If less than the torque sub signal is determined to be normal and fail-safe by applying a fail-safe (Fail-Safe) to the torque main signal (Limp Home Mode) to activate the torque sub signal after Electronic system for controlling to generate an assist current according to the torque sub-signal and to transmit to the motor Unit (ECU: Electronic Control Unit) A method for controlling a fail-safe of a vehicle, comprising: a motorized steering apparatus. The method of claim 1, The electronic control unit, A method for controlling fail-safe of a vehicle, characterized by controlling to transmit a reduced assist current reduced by a predetermined amount of current from the assist current to the motor in order to minimize malfunction caused by abnormality of the torque sub-signal. Electric steering device. (a) generating a torque average value for calculating an average of absolute values of the sum of the torque main signal and the torque sub signal; (b) checking whether the torque main signal exceeds a preset upper limit or is less than a preset lower limit; (c) If the check result of step (b) exceeds or exceeds the lower limit, it is considered that a failure has occurred in the torque main signal, and the torque average value exceeds the preset first reference value. Checking whether the reference value is less than the set second reference value; (d) When the torque average value exceeds the first reference value and is less than the second reference value as a result of the checking in step (c), it is determined that the torque sub-signal is normal and fail-safe to the torque main signal. -Safe) to deactivate; And (e) activating the torque sub-signal by switching to a limp home mode and generating an assist current according to the torque sub-signal and transmitting it to the motor; Method for controlling a fail-safe of a vehicle comprising a.

Images