Slope-descending speed control device for a vehicle

Patent metadata

Field	Value
Publication number	US-9764717-B2
Application number	US-201414917049-A
Country	US
Kind code	B2
Filing date	Sep 25, 2014
Priority date	Sep 27, 2013
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

A slope-descending speed control device 10 for a vehicle configured to control a vehicle deceleration so that an actual vehicle speed conforms to a target vehicle speed in accordance with a target deceleration Gxbt of a PID feedback control executed in accordance with a difference between a target vehicle speed Vxt and an actual vehicle speed Vx. In a situation where an actual vehicle speed is higher than a target vehicle speed, with a component in a hill-descending direction of gravitational acceleration of the vehicle at a time point when a condition for starting a slope-descending speed control is satisfied being a reference gravitational acceleration Gxd0, when a difference between a component Gxd in a hill-descending direction of gravitational acceleration and the reference gravitational acceleration Gxd0 is between upper and lower reference values, a target deceleration Gxbti of the integral term is not integrated to restrain its increase.

First claim

The invention claimed is:

1. A slope-descending speed control device for a vehicle having a control unit which is configured to control a deceleration of a vehicle, when a predetermined condition for starting a slope-descending speed control is satisfied, so that an actual vehicle speed conforms to a target vehicle speed in accordance with at least a target deceleration of an integral term of a PID feedback control executed in accordance with a difference between a target vehicle speed and an actual vehicle speed, wherein
said control unit calculates a component in a hill-descending direction of gravitational acceleration of the vehicle
when an actual vehicle speed is higher than a target vehicle speed, with a reference value for determining a magnitude of a component in a hill-descending direction of gravitational acceleration of the vehicle being referred to a determination reference value, said control unit suppresses the increase of a target deceleration of said integral term in accordance with the magnitude of a difference between a component in a hill-descending direction of gravitational acceleration of the vehicle and said determination reference value.

2. The slope-descending speed control device for a vehicle according to claim 1 , wherein said control unit calculates upper and lower reference values for preventing a target deceleration of said integral term from being integrated on the basis of said determination reference value, and when a component in a hill-descending direction of gravitational acceleration of the vehicle is between said upper and lower reference values, the control unit does not integrate a target deceleration of said integral term.

3. The slope-descending speed control device for a vehicle according to claim 1 , wherein as a difference between a component in a hill-descending direction of gravitational acceleration of the vehicle and said determination reference value is smaller in magnitude, said control unit decreases the magnitude of a gain for integrating a target deceleration of said integral term.

4. The slope-descending speed control device for a vehicle according to claim 1 , wherein with a component in a hill-descending direction of gravitational acceleration of the vehicle at a time point when said condition is satisfied being a reference gravitational acceleration, said control unit calculates a target deceleration of the vehicle on the basis of a target deceleration based on said reference gravitational acceleration and at least a target deceleration of said integral term, and controls a deceleration of the vehicle in accordance with said target deceleration of the vehicle.

5. The slope-descending speed control device for a vehicle according to claim 4 , wherein said determination reference value is set on the basis of said reference gravitational acceleration.

6. The slope-descending speed control device for a vehicle according to claim 4 , wherein said control unit calculates upper and lower guard values for limiting in magnitude a target deceleration of said integral term on the basis of said reference gravitational acceleration, and conducts a guard process on a target deceleration of said integral term with said upper and lower guard values.

Assignees

• Toyota Motor Co Ltd

Inventors

• Yasutomi Taisuke
• Murayama Takemi
• Kato Hideki

Classifications

• B60T2201/04

  Hill descent control · CPC title

• B60T7/12 Primary

  for automatic initiation; for initiation not subject to will of driver or passenger {(limiting speed of vehicles other than rail vehicles B60K31/00)} · CPC title

• B60T8/245

  Longitudinal vehicle inclination · CPC title