Park assist with tire radius consideration

Patent metadata

Field	Value
Publication number	US-2017282914-A1
Application number	US-201715626909-A
Country	US
Kind code	A1
Filing date	Jun 19, 2017
Priority date	Mar 4, 2015
Publication date	Oct 5, 2017
Grant date	—

Abstract

A vehicle, a vehicle parking assist system, and a parking method, is provided. A powertrain and a steering system may be operated to guide the vehicle into a parking location to complete a drive cycle based on a default tire radius, a tire angular velocity acquired during a drive cycle in response to a steering angle of the steering system exceeding a threshold value, and wheel and GPS vehicle speeds for the drive cycle.

First claim

What is claimed is:

1 . A vehicle comprising:
a powertrain; a steering system; and a controller programmed to, in response to a steering angle of the steering system exceeding a threshold value, operate the powertrain and steering system to guide the vehicle into a parking location to complete a drive cycle based on a default tire radius, a tire angular velocity acquired during the drive cycle, and wheel and GPS vehicle speeds for the drive cycle.

2 . The vehicle of claim 1 further comprising:
a wheel speed sensor disposed proximate a tire spaced apart from a default tire; and
a parking sensor configured to identify the parking location, wherein the controller is further programmed to provide the default tire radius prior to the parking sensor identifying the parking location, and wherein the default tire radius is based on a yaw rate, a track width, and the tire angular velocity.

3 . The vehicle of claim 2 wherein the controller is further programmed to guide the vehicle into the parking location further based on the default tire radius and a tire angular velocity of the tire spaced apart from the default tire.

4 . The vehicle of claim 3 wherein the controller is further programmed to guide the vehicle into the parking location based on the GPS vehicle speed, the tire angular velocity, the tire angular velocity of the tire spaced apart from the default tire, and a wheel slip estimate.

5 . A vehicle comprising:
an engine; a steering system; a parking sensor configured to identify a parking location for a vehicle relative to a curb; and a controller programmed to, in response to a park assist request, operate the engine and the steering system to guide the vehicle into the parking location based on a yaw rate, GPS vehicle speed, wheel speed, and initial tire radius such that changes in tire radius away from the initial tire radius during a preceding drive cycle do not cause a distance between a parked location of the vehicle and the curb to be greater than a predetermined threshold distance.

6 . The vehicle of claim 5 wherein the initial tire radius is associated with a reference tire disposed proximate a rear axle of the vehicle.

7 . The vehicle of claim 6 wherein the changes in tire radius away from the initial tire radius are based on the initial tire radius, and first and second tire radius estimates associated with a tire laterally spaced apart from the reference tire.

8 . The vehicle of claim 7 wherein the initial tire radius is based on an angular velocity of the reference tire, a vehicle track width, and the yaw rate.

9 . The vehicle of claim 8 wherein the first tire radius estimate is based on the initial tire radius, an angular velocity of the tire spaced apart from the reference tire, and the vehicle track width.

10 . The vehicle of claim 8 wherein the second tire radius estimate is based on the wheel speed, the GPS vehicle speed, and a net wheel torque.

11 . A vehicle comprising:
a controller programmed to operate a steering system to guide the vehicle into a parked position relative to a curb based on a yaw rate, GPS vehicle speed, wheel speed, track width, and default tire radius such that changes in tire radius away from the default tire radius during a drive cycle do not cause a distance between the parked position and the curb to be greater than a predetermined threshold distance.

12 . The vehicle of claim 11 wherein the default tire radius is associated with a reference tire disposed proximate a rear axle of the vehicle.

13 . The vehicle of claim 12 wherein the changes in tire radius away from the default tire radius are based on the default tire radius, and first and second tire radius estimates associated with a tire spaced apart from the reference tire.

14 . The vehicle of claim 13 wherein the first tire radius estimate is based on the default tire radius, an angular velocity of the tire spaced apart from the reference tire, and the track width.

15 . The vehicle of claim 13 wherein the second tire radius estimate is based on the wheel speed, the GPS vehicle speed, and a net wheel torque.

16 . The vehicle of claim 12 wherein the default tire radius is based on an angular velocity of the reference tire, the track width, and the yaw rate.

Assignees

• Ford Global Tech Llc

Inventors

• Lavoie Erick Michael
• Bayar Kerem
• Brewer Michael Edward

Classifications

• B60W40/10

  related to vehicle motion · CPC title

• B60W30/06 Primary

  Automatic manoeuvring for parking · CPC title

• B60W10/20

  including control of steering systems · CPC title

• B62D15/027 Primary

  Parking aids, e.g. instruction means · CPC title

• B60W10/04

  including control of propulsion units · CPC title