CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C. § 119(a) to Korean Patent Application No. 10-2019-0118662 filed on Sep. 26, 2019 in the Korean Intellectual Property Office, which is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

Embodiments of the present disclosure relate to an apparatus for and a method of compensating for a steering error in an advanced driving assistance system, and more particularly, to an apparatus for and a method of compensating for a steering error in an advanced driving assistance system, which compensate for an abnormal command steering angle input from the advanced driving assistance system, and thus ensure the stability of vehicle driving.

2. Related Art

An advanced driving assistance system (ADAS) assists a driver in driving a vehicle. The ADAS senses a situation in front of the vehicle, determines the situation on the basis of a result of the sensing, and controls the vehicle driving. For example, a sensing device in the ADAS detects a forward vehicle and recognizes a lane. Subsequently, when a target lane, a target speed, and a forward target are determined, an electrical stability control (ESC), an engine management system (EMS), a motor-driven power steering (MDPS), and the like in the vehicle are controlled. Typically, the ADAS may be realized as an automatic parking system, a low-speed city driving assistance system, and a blind zone warning system, or the like.

The MDPS here adjusts motor driving according to a driving speed of the vehicle and thus controls steering power of a steering wheel. Specifically, MDPS controls the steering power, in a manner that requires less steering effort, during parking or low-speed driving and controls the steering power, in a manner that requires more steering effort, during high-speed driving, thereby providing the stability for high-speed driving.

Particularly, when the command steering angle is input from the advanced driving assistance system, the MDPS performs steering control according to the command steering angle. At this time, in a case where an error occurs in the advanced driving assistance system, the MDPS performs the steering control according to an abnormal command steering angle. This creates a need to secure a safety technology that enables the MDPS to autonomously detect or deal with the abnormal command steering angle.

An MDPS in the related art has a fail-safe function inside, but the fail-safe function is to deal with an error in the MDPS itself. Thus, the fail-safe function is still inadequate to deal with the abnormal command steering angle input from the advanced driving assistance system.

The related art of the present disclosure is disclosed in Korean Patent Application Laid-Open No. 10-2013-0044734 (May 3, 2013) entitled “FAIL-SAFE CONTROL METHOD AND APPARATUS FOR VEHICLE ORIENTATION CONTROL.”

SUMMARY

Various embodiments are directed to an apparatus for and a method of compensating for a steering error in an advanced driving assistance system that compensate for an abnormal command steering angle input from the advanced driving assistance system and thus ensure the stability of vehicle driving.

In an embodiment, an apparatus for compensating for a steering error in an advanced driving assistance system, the apparatus includes: a command steering angle correction module configured to correct a command steering angle according to whether or not the command steering angle input from the advanced driving assistance system satisfies a preset error compensation condition; and a motor control unit configured to control a motor of a motor-driven power steering system according to the command steering angle corrected by the command steering angle correction module.

In an embodiment, the command steering angle correction module is configured to include: a command steering angle restriction module configured to detect lateral acceleration on the basis of the command steering angle and to restrict the command steering angle according to the lateral acceleration; a vibration attenuation module configured to detect a change in sign, of the command steering angle, due to abnormal vibration in a leftward and rightward direction, of the command steering angle and to attenuate the abnormal vibration at the command steering angle according to the detected change in sign; and a command steering angle attenuation module configured to detect an amount of change in the command steering angle and to decrease the command steering angle according to the amount of change in the command steering angle.

In an embodiment, the command steering angle attenuation module is configured to include: an amount-of-change detection unit configured to detect an amount of change in the command steering angle; and a command steering angle attenuation unit configured to compare the amount of change in the command steering angle, which is detected by the amount-of-change detection unit, with a preset setting value of the amount of change in the command steering angle, and to decrease the amount of change in the command steering angle according to a result of the comparison.

In an embodiment, the vibration attenuation module is configured to include: a vibration detection unit configured to detect the abnormal vibration at the command steering angle on the basis of the number of times that a steering angular velocity of the command steering angle changes in sign; and a filter unit configured to remove a vibration frequency according to the number of times that the steering angular velocity detected by the vibration detection unit changes in sign.

In an embodiment, the vibration detection unit is configured to determine whether or not the number of times that the steering angular velocity changes in sign for a preset setting time is equal to or greater than the preset setting number of times that the change in sign occurs.

In an embodiment, the filter unit is configured to: detect a vibration frequency according to the number of times that the steering angular velocity changes in sign, set a center frequency according to the vibration frequency, and remove the vibration frequency according to the center frequency.

In an embodiment, the command steering angle restriction module is configured to include: a vehicle modeling unit configured to detect the lateral acceleration on the basis of the command steering angle and a vehicle speed, and to detect a maximum necessary steering angle that is possible at a current vehicle speed, according to the lateral acceleration, using a vehicle model; and a command steering angle restriction unit configured to detect a necessary reduction steering angle on the basis of the command steering angle and to impose the restriction of decreasing the command steering angle by the necessary reduction steering angle.

In an embodiment, the vehicle modeling unit is configured to detect the necessary steering angle when the lateral acceleration is at or above a preset setting value of the lateral acceleration.

In an embodiment, a method of compensating for a steering error in an advanced driving assistance system includes: correcting, by a command steering angle correction module, a command steering angle according to whether or not the command steering angle input from the advanced driving assistance system satisfies a preset error compensation condition; and controlling, by a motor control unit, a motor of a motor-driven power steering system according to the command steering angle corrected by the command steering angle correction module.

In an embodiment, the correcting of the command steering angle is configured to include: detecting lateral acceleration on the basis of the command steering angle and restricting the command steering angle according to the lateral acceleration; detecting a change in sign, of the command steering angle, due to abnormal vibration in a leftward and rightward direction, of the command steering angle and attenuating the abnormal vibration at the command steering angle according to the detected change in sign; and detecting an amount of change in the command steering angle and decreasing the command steering angle according to the amount of change in the command steering angle.

In an embodiment, the decreasing of the command steering angle is configured to include: detecting the amount of change in the command steering angle; and comparing the amount of change in the command steering angle with a preset setting value of the amount of change in the command steering angle and decreasing the amount of change in the command steering angle according to a result of the comparison.

In an embodiment, the attenuating of the abnormal vibration at the command steering angle is configured to include: detecting the abnormal vibration at the command steering angle on the basis of the number of times that a steering angular velocity of the command steering angle changes in sign; and removing a vibration frequency according to the number of times that the steering angular velocity changes in sign.

In an embodiment, the detecting of the abnormal vibration at the command steering angle is configured to determine whether or not the number of times that the steering angular velocity changes in sign for a preset setting time is equal to or greater than the preset setting number of times that the change in sign occurs.

In an embodiment, the removing of the vibration frequency is configured to detect the vibration frequency according to the number of times that the steering angular velocity changes in sign, to set a center frequency according to the vibration frequency, and to remove the vibration frequency according to the center frequency.

In an embodiment, the decreasing of the command steering angle is configured to include: detecting the lateral acceleration on the basis of the command steering angle and a vehicle speed, and detecting a maximum necessary steering angle that is possible at a current vehicle speed, according to the lateral acceleration, using a vehicle model; and detecting a necessary reduction steering angle on the basis of the command steering angle and imposing the restriction of decreasing the command steering angle by the necessary reduction steering angle.

In an embodiment, the detecting of the necessary steering angle using the vehicle model is configured to detect the necessary steering angle when the lateral acceleration is at or above a preset setting value of the lateral acceleration.

The apparatus for and the method of compensating for a steering error in an advanced driving assistance system according to an aspect of the present disclosure compensate for the abnormal command steering angle input from the advanced driving assistance system and thus ensure the stability of vehicle driving and the safety of a driver.

