Parking brake fail safety control system for vehicle having electric-axle and method thereof

Patent metadata

Field	Value
Publication number	US-12059960-B2
Application number	US-202117402912-A
Country	US
Kind code	B2
Filing date	Aug 16, 2021
Priority date	Mar 16, 2021
Publication date	Aug 13, 2024
Grant date	Aug 13, 2024

Abstract

A parking brake fail safety control system and method for a vehicle having an electric-axle, may enable safe parking braking on a level ground, a slope, etc. By controlling the torque from a first motor configured for a rear wheel-first electric-axle and the torque from a second motor configured for a rear wheel-second electric-axle to have the same magnitude in opposite directions and by increasing/decreasing the torque from the first motor and the torque from the second motor, depending on a change of wheel speed when a parking brake fails.

First claim

What is claimed is:

1. A parking brake fail safety control system for a vehicle having an electric-axle, the system comprising:
a parking brake switch of a vehicle and configured to be turned on in response to a driver's operation;
a wheel speed sensor of the vehicle and configured for detecting a change in wheel speed of the vehicle;
a first motor of the vehicle and included in a rear wheel-first electric-axle of the vehicle, wherein the electric-axle of the vehicle includes the rear wheel-first electric-axle;
a second motor of the vehicle and included in a rear wheel-second electric-axle of the vehicle, wherein the electric-axle of the vehicle further includes the rear wheel-second electric-axle; and
a controller of the vehicle and electrically connected to the parking brake switch, the wheel speed sensor, the first motor and the second motor and configured for determining that a parking brake of the vehicle fails and controlling torque of the first motor and torque of the second motor to have a same magnitude in opposite directions upon determining that there is the change in the wheel speed according to a signal received from the wheel speed sensor after receiving a turning-on signal of the parking brake switch,
wherein the wheel speed sensor, the first motor, the second motor and the controller are all mounted in one vehicle.

2. The system of claim 1 , further including a door-opening sensor electrically connected to the controller and configured for outputting an opening signal when a door of the vehicle is open, to facilitate the controller to determine whether the parking brake fails.

3. The system of claim 2 , wherein the controller is configured to determine that the parking brake fails and to control the torque of the first motor and the torque of the second motor to have the same magnitude in the opposite directions, upon determining that there is the change in the wheel speed according to the signal received from the wheel speed sensor after receiving the opening signal from the door-opening sensor.

4. The system of claim 1 , further including a longitudinal acceleration sensor electrically connected to the controller and configured for facilitating the controller to determine whether the vehicle is on an uphill slope with a positive slope or a downhill slope with a negative slope upon determining that there is still the change in the wheel speed after the torque of the first motor and the torque of the second motor are controlled to have the same magnitude in the opposite directions.

5. The system of claim 4 , wherein the controller is configured to decrease the torque of the first motor until the wheel speed becomes zero when the wheel speed is greater than 0 and increases the torque of the first motor until the wheel speed becomes zero when the wheel speed is smaller than 0, when the controller determines that the vehicle is on the uphill slope according to a signal received from the longitudinal acceleration sensor.

6. The system of claim 4 , wherein the controller is configured to increase the torque of the second motor until the wheel speed becomes zero when the wheel speed is greater than 0 and to decrease the torque of the second motor until the wheel speed becomes zero when the wheel speed is smaller than 0, when the controller determines that the vehicle is on the downhill slope according to a signal received from the longitudinal acceleration sensor.

7. The system of claim 4 , wherein the controller is configured to decrease the torque of the first motor until the wheel speed becomes zero when the wheel speed is greater than 0 and to decrease the torque of the second motor until the wheel speed becomes zero when the wheel speed is smaller than 0, even though the controller determines that the vehicle is not on the uphill slope or the downhill slope according to a signal received from the longitudinal acceleration sensor.

8. A parking brake fail safety control method for a vehicle having an electric-axle, the method comprising:
determining, by a controller, whether a parking brake switch of the vehicle and electrically connected to the controller is turned on;
determining, by the controller, whether a parking brake of the vehicle fails; and
controlling, by the controller, torque of a first motor of the vehicle and included in a rear wheel-first electric-axel of the vehicle and torque of a second motor of the vehicle and included in a rear wheel-second electric-axle of the vehicle to have a same magnitude in opposite directions, when the controller determines that the parking brake fails,
wherein the electric-axle of the vehicle includes the rear wheel-first electric-axle and the rear wheel-second electric-axle,
wherein the first motor, the second motor and the controller are all mounted in one vehicle.

9. The method of claim 8 , wherein the determining of whether a parking brake fails includes:
detecting a wheel speed of the vehicle by a wheel speed sensor electrically connected to the controller;
checking whether there is a change in the wheel speed according to a detection signal received from the wheel speed sensor after receiving a turning-on signal from the parking brake switch; and
determining that the parking brake fails when there is the change in the wheel speed.

10. The method of claim 8 , wherein the determining of whether a parking brake fails includes:
detecting, by a door-opening sensor electrically connected to the controller, whether a door of the vehicle is opened;
detecting a wheel speed of the vehicle by a wheel speed sensor electrically connected to the controller;
checking, by the controller, whether there is a change in the wheel speed according to a detection signal received from the wheel speed sensor after a door-opening signal is received from the door-opening sensor; and
determining, by the controller, that the parking brake fails when there is the change in the wheel speed.

11. The method of claim 8 , further including determining whether the vehicle is on an uphill slope with a positive slope or a downhill slope with a negative slope when there is still the change in the wheel speed after the torque of the first motor and the torque of the second motor are controlled by the controller to have the same magnitude in the opposite directions.

12. The method of claim 11 , wherein when the controller determines that the vehicle is on the uphill slope, the torque of the first motor is decreased by the controller until the wheel speed becomes zero when the wheel speed is greater than 0 and the torque of the first motor is increased by the controller until the wheel speed becomes zero when the wheel speed is smaller than 0.

13. The method of claim 11 , wherein when the controller determines that the vehicle is on the downhill slope, the torque of the second motor is increased by the controller until the wheel speed becomes zero when the wheel speed is greater than 0 and the torque of the second motor is decreased by the controller until the wheel speed becomes zero when the wheel speed is smaller than 0.

14. The method of claim 11 , wherein even though the controller determines that the vehicle is not on the uphill slope or the downhill slope, the torque of the first motor is decreased by the controller until the wheel speed becomes zero when the wheel speed is greater than 0 and the torque of the second motor is decreased by the controller until the wheel speed becomes zero when the wheel speed is smaller than 0.

15. The method of claim 8 , wherein the controller includes:
a processor configured for executing a program for performing the method of claim 8 ; and

Assignees

• Hyundai Motor Co Ltd
• Kia Corp

Inventors

• Oh June

Classifications

• B60T2220/00

  Monitoring, detecting driver behaviour; Signalling thereof; Counteracting thereof · CPC title

• B60T7/02

  for personal initiation · CPC title

• B60T2270/402

  Back-up · CPC title

• B60T2210/20

  Road shapes · CPC title

• B60T2250/00

  Monitoring, detecting, estimating vehicle conditions · CPC title