Vehicle control device and control method

Patent metadata

Field	Value
Publication number	US-11021068-B2
Application number	US-201816480353-A
Country	US
Kind code	B2
Filing date	Jan 16, 2018
Priority date	Jan 24, 2017
Publication date	Jun 1, 2021
Grant date	Jun 1, 2021

Abstract

A method for controlling a vehicle that includes a motor configured to provide a driving/braking force to the vehicle and a friction braking mechanism configured to provide a friction brake force to the vehicle includes a target calculation step of calculating a target torque of the motor in accordance with a displacement of an accelerator pedal, a gradient estimation step of estimating a gradient torque to cancel a disturbance due to a gradient of a road surface where the vehicle is travelling, a command calculation step of calculating a torque command value of the motor based on the gradient torque and the target torque, a control step of controlling a torque of the motor in accordance with the torque command value, and a stop control step.

First claim

The invention claimed is:

1. A method for controlling a vehicle, the vehicle including a motor configured to provide a driving/braking force to the vehicle and a friction braking mechanism configured to provide a friction brake force to the vehicle, the method comprising:
a target calculation step of calculating a target torque of the motor in accordance with a displacement of an accelerator pedal;
a gradient estimation step of estimating a gradient torque to cancel a disturbance due to a gradient of a road surface where the vehicle is travelling;
a command calculation step of calculating a torque command value of the motor based on the gradient torque and the target torque;
a control step of controlling a torque of the motor in accordance with the torque command value; and
a stop control step of determining whether the vehicle stops or not, changing a brake torque from the torque of the motor to a friction torque provided by the friction braking mechanism at the determination that the vehicle stops, the brake torque being provided to the vehicle and made to a large value larger than the gradient torque,
wherein, in the stop control step, after the determination that the vehicle stops, increasing a pressure-rising rate of fluid to be supplied to the friction braking mechanism until the friction torque reaches the large value in accordance with increase in time elapsed after the determination.

2. The method for controlling the vehicle according to claim 1 ,
wherein the stop control step determines whether a parameter proportional to the vehicle speed falls below a threshold or not, and when the parameter falls below the threshold, increases the friction torque to a vehicle-stop torque that is larger than an absolute value of the gradient torque.

3. The method for controlling the vehicle according to claim 2 ,
wherein the vehicle-stop torque is set beforehand based on temperature characteristics of the fluid to be supplied to the friction braking mechanism.

4. The method for controlling the vehicle according to claim 1 ,
wherein the gradient estimation step corrects the gradient torque to decrease, and when the vehicle stops, brings a correction amount of the gradient torque closer to zero with decrease in the vehicle speed.

5. The method for controlling the vehicle according to claim 4 ,
wherein the gradient estimation step corrects the gradient torque to decrease with increase in the gradient torque.

6. The method for controlling the vehicle according to claim 4 ,
wherein the friction braking mechanism includes a parking brake, and the gradient estimation step suppresses correction of the gradient torque when the parking brake provides a friction brake force to the vehicle.

7. The method for controlling the vehicle according to claim 4 ,
wherein the gradient estimation step determines whether the vehicle is in a slipping state or not, and when the gradient estimation step determines that the vehicle is in a slipping state, limits the gradient torque.

8. The method for controlling the vehicle according to claim 4 ,
wherein when the vehicle stops in a slipping state, the stop control step increases the friction torque as compared with stopping of the vehicle in a not slipping state.

9. The method for controlling the vehicle according to claim 1 ,
wherein when the speed of the vehicle decreases to a predetermined value, the stop control step increases the friction torque with increase in movement amount of the vehicle.

10. The method for controlling the vehicle according to claim 9 ,
wherein when the stop control step detects movement of the vehicle after stopping of the vehicle, the stop control step increases the friction torque in accordance with the amount of the movement of the vehicle.

11. The method for controlling the vehicle according to claim 10 ,
wherein when a shift lever of the vehicle moves between a D range and a R range, the stop control step suppresses an increase of the friction torque.

12. The method for controlling the vehicle according to claim 10 ,
wherein when the vehicle moves in the direction opposite of the travelling direction, the stop control step increases an increasing amount or an increasing rate of the friction torque as compared with the case of movement of the vehicle in a same direction as the travelling direction.

13. The method for controlling the vehicle according to claim 1 ,
wherein when the stop control step detects movement of the vehicle after stopping of the vehicle, the stop control step increases the friction torque to a predetermined value.

14. The method for controlling the vehicle according to claim 13 ,
wherein the stop control step increases the predetermined value in accordance with the amount of the movement of the vehicle from a first timing when the vehicle starts to move to a second timing when the movement of the vehicle is detected.

15. The method for controlling the vehicle according to claim 13 ,
wherein when the vehicle stops and when movement of a shift lever of the vehicle from a P range to another range is detected, the stop control step increases the friction torque.

16. A control device of a vehicle comprising:
a motor configured to provide a driving/braking force to the vehicle;
a friction braking mechanism configured to provide a friction brake force to the vehicle; and
a controller configured to estimate a gradient torque to cancel a disturbance acting on the vehicle, calculate a torque command value of the motor based on a target torque of the motor based on the gradient torque and a displacement of an accelerator pedal, and control the motor in accordance with the torque command value,
wherein the controller is configured to determine whether the vehicle stops or not, execute a stop control processing of changing a brake torque from the torque of the motor to a friction torque provided by the friction braking mechanism at the determination that the vehicle stops, providing the brake torque to the vehicle, and making the brake torque to a large value larger than the gradient torque,
wherein, in the stop control step, the controller:
after the determination that the vehicle stops, increases a pressure-rising rate of fluid to be supplied to the friction braking mechanism until the friction torque reaches the large value in accordance with increase in time elapsed after the determination.

17. A method for controlling a vehicle, the vehicle including a motor configured to provide a driving/braking force to the vehicle and a friction braking mechanism configured to provide a friction brake force to the vehicle, the method comprising:
a target calculation step of calculating a target torque of the motor in accordance with a displacement of an accelerator pedal;
a gradient estimation step of estimating a gradient torque to cancel a disturbance due to a gradient of a road surface where the vehicle is travelling;
a command calculation step of calculating a torque command value of the motor based on the gradient torque and the target torque;
a control step of controlling a torque of the motor in accordance with the torque command value; and
a stop control step of determining whether or not the vehicle stops or not, changing a brake torque from the torque of the motor to a friction torque provided by the friction braking mechanism at the determination that the vehicle stops, the brake torque being provided to the vehicle and made to a large value larger than the gradient torque,
wherein, in the stop control step, after the determination that the vehicle stops, increasing a

Assignees

• Nissan Motor

Inventors

• Shindo Ikuma
• Suzuki Tatsuya
• Ohta Mitsunori

Classifications

• B60L2240/423

  Torque · CPC title

• B60W10/188

  hydraulic brakes · CPC title

• B60L15/2018 Primary

  for braking on a slope · CPC title

• B60L2210/40

  DC to AC converters · CPC title

• B60L7/24

  with additional mechanical or electromagnetic braking · CPC title