Stop determination apparatus, inclination determination apparatus, and electric parking brake controller

• US 20070173984A1
• Filed: 01/04/2007
• Published: 07/26/2007
• Est. Priority Date: 01/06/2006
• Status: Active Grant

• Current Assignee: Subaru Corp.
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Nakayama, Daisuke
• Granted Patent: US 8,086,384 B2
• Time in Patent Office: Days
• US Class Current: 701/1
• CPC Class Codes: B60T 13/74 with electrical assistance or drive
• CPC Class Codes: B60T 2201/06 Hill holder; Start aid systems on inclined road
• CPC Class Codes: B60T 7/12 for automatic initiation; for initiation not subject to will of driver or passenger limiting speed of vehicles other than rail vehicles B60K31/00
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60W 2552/15 Road slope, i.e. the inclination of a road segment in the longitudinal direction
• CPC Class Codes: B60W 30/18118 Hill holding
• CPC Class Codes: G01P 13/00 Indicating or recording presence, absence, or direction, of movement electric switches H01H; counting moving objects G06M7/00

Abstract

A vehicle stop determination apparatus includes a vehicle speed sensor for detecting a speed of a vehicle, a G sensor for detecting a longitudinal acceleration of a vehicle, an inclination acceleration estimate section for calculating an estimated inclination acceleration resulting from an inclination of a road surface based on a vehicle speed reduction rate calculated from an output of the vehicle speed sensor and an output from the G sensor, and a stop determination section which has a first stop determination mode and a second stop determination mode and which selects the first stop determination mode or the second stop determination mode based on the vehicle speed reduction rate provided before the output of the vehicle speed sensor becomes equal to or less than a detection limit. Also, the inclination is re-determined based on the output of the G sensor when the vehicle is stopped.

Claims

1. A vehicle stop determination apparatus for determining whether a vehicle is at a standstill, comprising:

a vehicle speed sensor for detecting a speed of a vehicle;

a G sensor for detecting a longitudinal acceleration of the vehicle;

an inclination acceleration estimate section for calculating an estimated inclination acceleration resulting from an inclination of a road surface based on a vehicle speed reduction rate calculated from an output of the vehicle speed sensor and an output from the G sensor; and

a stop determination section which has a first stop determination mode and a second stop determination mode and which selects the first stop determination mode or the second stop determination mode based on the vehicle speed reduction rate calculated before the output of the vehicle speed sensor falls below a detection limit, wherein in the first stop determination mode, a stop of the vehicle is determined based on a change in the output of the G sensor when the output of the vehicle speed sensor is equal to or less than the detection limit, and in the second stop determination mode, the output of the G sensor and the estimated inclination acceleration are compared to each other to determine a stop of the vehicle.

2. The vehicle stop determination apparatus according to claim 1, wherein, in the first stop determination mode, the determination of a stop is made based on a change in the output of the G sensor from a decelerating side to an accelerating side.

3. The vehicle stop determination apparatus according to claim 1, wherein, in the first stop determination mode, the determination of a stop is made according to a convergence in variations in the output of the G sensor.

4. The vehicle stop determination apparatus according to claim 3, wherein, in the first stop determination mode, the determination of a stop is established when variations in the output of the G sensor are equal to or less than a pre-defined threshold value over a predetermined period of time.

5. The vehicle stop determination apparatus according to claim 1, further comprising an estimated stop time computation section for calculating an estimated stop time based on the detection limit and the vehicle speed reduction rate when the output of the vehicle speed sensor is equal to or less than the detection limit,

wherein the stop determination section further has a third stop determination mode in which a stop of the vehicle is determined after the estimated stop time elapses.

6. The vehicle stop determination apparatus according to claim 1, wherein the stop determination section further has a fourth stop determination mode in which a stop of the vehicle is automatically determined regardless of the stop determination determined by the first step determination mode and the second step determination mode when the output of the vehicle speed sensor is equal to or less than the detection limit over a predetermined stand-by time period.

7. An electric parking brake controller comprising:

the vehicle stop determination apparatus according to claim 1; and

an electric parking brake control section for controlling an electric actuator to change braking force of a parking brake and thereby switch the electric actuator between a braking state and a released state of the parking brake,

wherein when the vehicle stop determination apparatus establishes a determination of a stop of the vehicle, the electric parking brake control section allows the parking brake to transition into the braking state.

8. An inclination determination apparatus for determining an inclination of a road surface on which a vehicle is stopped, the inclination determination apparatus comprising:

a vehicle speed sensor for detecting a speed of a vehicle;

a G sensor for detecting a longitudinal acceleration of the vehicle;

an inclination determination section for calculating an estimated inclination acceleration resulting from an inclination of a road surface based on a vehicle speed reduction rate calculated from an output of the vehicle speed sensor and an output from the G sensor; and

a stop determination section for determining a stop of the vehicle based on the output of the vehicle speed sensor,

wherein the inclination determination section determines the inclination to be a flat surface if the estimated inclination acceleration is below a predetermined criterion value, and re-determines the inclination based on the output of the G sensor when the stop determination section establishes a determination of a stop of the vehicle.

9. An electric parking brake controller comprising:

the inclination determination apparatus according to claim 8; and

an electric parking brake control section for controlling an electric actuator to change braking force of a parking brake,

wherein, when the stop determination section establishes a determination of a stop of the vehicle, the electric parking brake control section sets the braking force of the parking brake based on an estimated inclination acceleration calculated by the inclination determination section.