Electric vehicle, active safety control system for electric vehicle, and control method for active safety control system of electric vehicle

• US 10,343,525 B2
• Filed: 12/16/2015
• Issued: 07/09/2019
• Est. Priority Date: 12/16/2014
• Status: Active Grant

• Current Assignee: BYD Company Limited
• Original Assignee: BYD Company Limited
• Inventors: Lian, Yubo, Luo, Hongbin, Zhang, Jintao, Yang, Dongsheng, Lv, Haijun
• Primary Examiner(s): Cass, Jean Paul
• Application Number:
  US15/518,928
• Publication Number:
  US 20170232848A1
• Time in Patent Office: 1,301 Days
• Field of Search: None
• CPC Class Codes: B60K 17/356 having fluid or electric motor, for driving one or more wheels disposition of motor in, or adjacent to, traction wheel B60K7/00
• CPC Class Codes: B60L 15/36 with automatic control superimposed, e.g. to prevent excessive motor current
• CPC Class Codes: B60L 3/102 of individual wheels
• CPC Class Codes: B60L 3/106 for maintaining or recovering the adhesion of the drive wheels
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 10/192 electric brakes
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/20 Sideslip angle
• CPC Class Codes: B60W 2520/28 Wheel speed
• CPC Class Codes: B60W 2540/18 Steering angle
• CPC Class Codes: B60W 2710/08 Electric propulsion units
• CPC Class Codes: B60W 2710/083 Torque
• CPC Class Codes: B60W 2710/18 Braking system
• CPC Class Codes: B60W 2720/14 Yaw
• CPC Class Codes: B60W 2720/20 Sideslip angle
• CPC Class Codes: B60W 30/02 Control of vehicle driving stability
• CPC Class Codes: B60W 30/18145 : Cornering
• CPC Class Codes: B60W 30/18172 : Preventing, or responsive to skidding of wheels
• CPC Class Codes: B60Y 2200/91 : Electric vehicles
• CPC Class Codes: Y02T 10/64 : Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility

Abstract

The present disclosure discloses an electric vehicle, an active safety control system of an electric vehicle, and a control method of the active safety control system of an electric vehicle. The electric vehicle includes: multiple wheels, multiple motors, a wheel speed detection module, a steering wheel rotation angle sensor, a yaw rate sensor, and a battery pack. The active safety control system includes: an acquisition module, acquiring the wheel speed signal, the direction information, the yaw information, status information of the battery pack, and status information of the multiple motors; a status determining module, determining status of the electric vehicle; and a control module, generating a control instruction and delivering the control instruction to at least one motor.

Claims

1. An active safety control system used for an electric vehicle, wherein the electric vehicle comprises:

multiple wheels,

multiple transmissions, respectively connected to the multiple wheels,

multiple motors, respectively connected to the multiple transmissions to respectively correspond to the multiple wheels,

a wheel speed detection module, configured to detect a wheel speed of the multiple wheels to generate a wheel speed signal,

a steering wheel rotation angle sensor, configured to detect direction information of the electric vehicle,

a yaw rate sensor, configured to detect yaw information of the electric vehicle, and

a battery pack;

wherein the active safety control system comprises;

an acquisition module, connected to the wheel speed detection module, the steering wheel rotation angle sensor, the yaw rate sensor, the battery pack, and the multiple motors, and configured to acquire the wheel speed signal, the direction information of the electric vehicle, the yaw information of the electric vehicle, status information of the battery pack, and status information of the multiple motors;

a status determining module, configured to determine status of the electric vehicle according to the wheel speed signal, the direction information of the electric vehicle, and the yaw information of the electric vehicle, wherein the status of the electric vehicle comprises that the electric vehicle has a side slip and is about to enter a side slip limit interval and that the electric vehicle is in the side slip limit interval;

a control module, configured to generate a control instruction according to the status information of the battery pack, the status information of the multiple motors, and the status of the electric vehicle, and deliver the control instruction to at least one motor, to enable the at least one motor to control at least one corresponding wheel according to the control instruction, wherein when the electric vehicle has a side slip and is about to enter the side slip limit interval, the control instruction enables the at least one motor to perform driving control on the at least one corresponding wheel; and

when the electric vehicle is in the side slip limit interval, the control instruction enables the at least one motor to perform braking control on the at least one corresponding wheel,

wherein the direction information of the electric vehicle is a steering wheel rotation angle signal that is detected by the steering wheel rotation angle sensor, and the yaw information of the electric vehicle comprises;

an actual yaw angular speed detected by the yaw angular speed sensor and a lateral acceleration detected by the lateral acceleration sensor; and

the status determining module is further configured to;

calculate a target yaw angular speed of the electric vehicle according to the steering wheel rotation angle signal and the wheel speed signal;

calculate a rear shaft slip angle of the electric vehicle according to the wheel speed signal, the steering wheel rotation angle signal, the actual yaw angular speed, and the lateral acceleration;

acquire a yaw angular speed difference Δ

ψ

′

between the target yaw angular speed and the actual yaw angular speed; and

when the yaw angular speed difference Δ

ψ

′

is greater than a first preset angular speed and is less than or equal to a second preset angular speed, or the rear shaft slip angle is greater than a first preset angle and is less than or equal to a second preset angle, determine that the electric vehicle has a side slip and is about to enter the side slip limit interval;

or when the yaw angular speed difference Δ

ψ

′

is greater than the second preset angular speed or the rear shaft slip angle is greater than the second preset angle, determine that the electric vehicle is in the side slip limit interval,

wherein the control module is further configured to;

acquire driving forces of the multiple wheels;

acquire braking forces of the multiple wheels;

calculate a target yaw moment of the electric vehicle according to the target yaw angular speed and overall vehicle rotary inertia of the electric vehicle, and acquire a yaw moment difference Δ

M between the target yaw moment and an actual yaw moment, wherein the actual yaw moment is detected by the yaw angular speed sensor; and

when the electric vehicle has a side slip and is about to enter the side slip limit interval, perform calculation according to the status information of the battery pack, the status information of the multiple motors, the driving forces of the multiple wheels, and the yaw moment difference Δ

M, to obtain a first opposite yaw moment, and deliver the first opposite yaw moment to the at least one motor, to enable the at least one motor to control, according to the first opposite yaw moment, the at least one corresponding wheel to drive; and

when the electric vehicle is in the side slip limit interval, perform calculation according to the status information of the battery pack, the status information of the multiple motors, the driving forces of the multiple wheels, the braking forces of the multiple wheels, and the yaw moment difference Δ

M to obtain a second opposite yaw moment, and deliver the second opposite yaw moment to the at least one motor, to enable the at least one motor to control, according to the second opposite yaw moment, the at least one corresponding wheel to brake.

2. The active safety control system according to claim 1, wherein when the electric vehicle is in the side slip limit interval, the control instruction generated by the control module enables one motor to perform braking control on a corresponding wheel and enables another motor to perform driving control on another corresponding wheel.

3. The active safety control system according to claim 1, wherein the wheel speed detection module comprises a wheel speed sensor and/or a rotary transformer sensor.

4. The active safety control system according to claim 1, wherein the yaw rate sensor comprises a yaw angular speed sensor, a vertical acceleration sensor, and a lateral acceleration sensor.

5. The active safety control system according to claim 1, wherein the multiple wheels comprise:

the left-front wheel, the right-front wheel, the left-rear wheel, and the right-rear wheel.

6. The active safety control system according to claim 5, wherein when a wheel that has a side slip is a front wheel and the electric vehicle turns right, the control module is further configured to:

when the electric vehicle has a side slip and is about to enter the side slip limit interval, calculate, according to the status information of the battery pack, the status information of the multiple motors, and the driving forces of the multiple wheels and the yaw moment difference Δ

M, a first driving force needed by the left-rear wheel, and deliver the first driving force to a motor corresponding to the left-rear wheel, to enable the motor corresponding to the left-rear wheel to control the left-rear wheel according to the first driving force; and

when the electric vehicle is in the side slip limit interval, calculate, according to the status information of the battery pack, the status information of the multiple motors, the driving forces of the multiple wheels, the braking forces of the multiple wheels, and the yaw moment difference Δ

M, a second driving force needed by the left-rear wheel and a first braking force needed by the right-rear wheel, and deliver the second driving force to the motor corresponding to the left-rear wheel and deliver the first braking force to a motor corresponding to the right-rear wheel, to enable the motor corresponding to the left-rear wheel to control the left-rear wheel according to the second driving force and the motor corresponding to the right-rear wheel to control the right-rear wheel according to the first braking force.

7. The active safety control system according to claim 5, wherein when a wheel that has a side slip is a front wheel and the electric vehicle turns left, the control module is further configured to:

when the electric vehicle has a side slip and is about to enter the side slip limit interval, calculate, according to the status information of the battery pack, the status information of the multiple motors, and the driving forces of the multiple wheels and the yaw moment difference Δ

M, a first driving force needed by the right-rear wheel, and deliver the first driving force to a motor corresponding to the right-rear wheel, to enable the motor corresponding to the right-rear wheel to control the right-rear wheel according to the first driving force; and

when the electric vehicle is in the side slip limit interval, calculate, according to the status information of the battery pack, the status information of the multiple motors, the driving forces of the multiple wheels, the braking forces of the multiple wheels, and the yaw moment difference Δ

M, a second driving force needed by the right-rear wheel and a first braking force needed by the left-rear wheel, and deliver the second driving force to the motor corresponding to the right-rear wheel and deliver the first braking force to a motor corresponding to the left-rear wheel, to enable the motor corresponding to the right-rear wheel to control the right-rear wheel according to the second driving force and the motor corresponding to the left-rear wheel to control the left-rear wheel according to the first braking force.

8. The active safety control system according to claim 5, wherein when a wheel that has a side slip is a rear wheel and the electric vehicle turns right, the control module is further configured to:

when the electric vehicle has a side slip and is about to enter the side slip limit interval, calculate, according to the status information of the battery pack, the status information of the multiple motors, the driving forces of the multiple wheels, and the yaw moment difference Δ

M, a third driving force needed by the right-front wheel, and deliver the third driving force to a motor corresponding to the right-front wheel, to enable the motor corresponding to the right-front wheel to control the right-front wheel according to the third driving force; and

when the electric vehicle is in the side slip limit interval, calculate, according to the status information of the battery pack, the status information of the multiple motors, the driving forces of the multiple wheels, the braking forces of the multiple wheels, and the yaw moment difference Δ

M, a fourth driving force needed by the right-front wheel and a second braking force needed by the left-front wheel, and deliver the fourth driving force to the motor corresponding to the right-front wheel and deliver the second braking force to a motor corresponding to the left-front wheel, to enable the motor corresponding to the right-front wheel to control the right-front wheel according to the fourth driving force and the motor corresponding to the left-front wheel to control the left-front wheel according to the second braking force.

9. The active safety control system according to claim 5, wherein when a wheel that has a side slip is a rear wheel and the electric vehicle turns left, the control module is further configured to:

when the electric vehicle has a side slip and is about to enter the side slip limit interval, calculate, according to the status information of the battery pack, the status information of the multiple motors, the driving forces of the multiple wheels, and the yaw moment difference Δ

M, a third driving force needed by the left-front wheel, and deliver the third driving force to a motor corresponding to the left-front wheel, to enable the motor corresponding to the left-front wheel to control the left-front wheel according to the third driving force; and

when the electric vehicle is in the side slip limit interval, calculate, according to the status information of the battery pack, the status information of the multiple motors, the driving forces of the multiple wheels, the braking forces of the multiple wheels, and the yaw moment difference Δ

M, a fourth driving force needed by the left-front wheel and a second braking force needed by the right-front wheel, and deliver the fourth driving force to the motor corresponding to the left-front wheel, and deliver the second braking force to a motor corresponding to the right-front wheel, to enable the motor corresponding to the left-front wheel to control the left-front wheel according to the fourth driving force, and the motor corresponding to the right-front wheel to control the right-front wheel according to the second braking force.

10. The active safety control system according to claim 1, wherein the active safety control system is integrated in a motor controller of the electric vehicle.

11. A motor controller, comprising the active safety control system used for an electric vehicle according to claim 1.