Electric vehicle and active safety control system and method thereof

Patent metadata

Field	Value
Publication number	US-10202114-B2
Application number	US-201615767869-A
Country	US
Kind code	B2
Filing date	Oct 26, 2016
Priority date	Oct 26, 2015
Publication date	Feb 12, 2019
Grant date	Feb 12, 2019

Abstract

The present disclosure discloses an electric vehicle and an active safety control system and method thereof. The system includes: a wheel speed detection module configured to detect a wheel speed to generate a wheel speed signal; a steering wheel rotation angle sensor and a yaw rate sensor module, configured to detect state information of the electric vehicle; a motor controller; and an active safety controller configured to receive the wheel speed signal and state information, obtain state information of a battery pack and state information of four motors, obtain a first side slip signal or a second side slip signal according to the wheel speed signal, the state information, the battery pack and the four motors, and according to the first side slip signal or the second side slip signal, control four hydraulic brakes of the electric vehicle and control the four motors by using the motor controller.

First claim

What is claimed is:

1. An active safety control system of an electric vehicle, comprising:
a wheel speed detection module, configured to detect a wheel speed of the electric vehicle to generate a wheel speed signal;
a steering wheel rotation angle sensor and a yaw rate sensor module, configured to detect state information of the electric vehicle;
a motor controller, configured to connect to four motors of the electric vehicle, respectively;
an active safety controller, configured to communicate with the motor controller mutually, to communicate with the steering wheel rotation angle sensor and the yaw rate sensor module, and to connect to each hydraulic brake of the electric vehicle, and receive the wheel speed signal sent by the wheel speed detection module and the state information of the electric vehicle sent by the steering wheel rotation angle sensor and the yaw rate sensor module, obtain state information of a battery pack of the electric vehicle and state information of the four motors, obtain a first side slip signal or a second side slip signal according to the wheel speed signal, the state information of the electric vehicle, the state information of the battery pack and the state information of the four motors, and control four hydraulic brakes of the electric vehicle and control the four motors by using the motor controller according to the first side slip signal or the second side slip signal, wherein the first side slip signal indicates that the electric vehicle has a side slip and is about to enter a side slip limit interval, and the second side slip signal indicates that the electric vehicle is in the side slip limit interval.

2. The active safety control system of an electric vehicle according to claim 1 , wherein the active safety controller is further configured to: perform yaw control on the electric vehicle by using driving torques of the four motors according to the first side slip signal; and perform the yaw control on the electric vehicle by using the driving torques and feedback braking torques of the four motors and using braking torques of the four hydraulic brakes simultaneously according to the second side slip signal.

3. The active safety control system of an electric vehicle according to claim 1 , wherein the wheel speed detection module comprises four wheel speed sensors and four rotary transformer sensors, wherein each wheel speed sensor is disposed corresponding to each wheel of the electric vehicle, and each rotary transformer sensor is disposed corresponding to each motor; and
the yaw rate sensor module comprises a yaw angular speed sensor, a vertical acceleration sensor, and a lateral acceleration sensor.

4. The active safety control system of an electric vehicle according to claim 3 , wherein in a driving process of the electric vehicle, the active safety controller is further configured to:
calculate a target yaw angular speed of the electric vehicle according to a steering wheel rotation angle signal detected by the steering wheel rotation angle sensor, a vertical acceleration detected by the vertical acceleration sensor and the wheel speed signal;
compare the target yaw angular speed with an actual yaw angular speed of the electric vehicle detected by the yaw angular speed sensor to obtain a yaw angular speed difference Δψ′;
calculate a rear shaft slip angle of the electric vehicle according to the wheel speed signal, the steering wheel rotation angle signal, the vertical acceleration, the actual yaw angular speed of the electric vehicle, and a lateral acceleration of the electric vehicle that is detected by the lateral acceleration sensor; and
obtain the first side slip signal when the yaw angular speed difference Δψ′ is greater than a first preset angular speed and is less than or equal to a second preset angular speed, or when the rear shaft slip angle is greater than a first preset angle and is less than or equal to a second preset angle; and
obtain the second side slip signal when the yaw angular speed difference Δψ′ is greater than the second preset angular speed, or when the rear shaft slip angle is greater than the second preset angle.

5. The active safety control system of an electric vehicle according to claim 4 , wherein the active safety controller is further configured to:
calculate a yaw moment difference ΔM between a target yaw moment and an actual yaw moment of the electric vehicle according to the target yaw angular speed, the actual yaw angular speed of the electric vehicle, and an overall vehicle rotary inertia of the electric vehicle;
when the yaw control is performed on the electric vehicle by using the driving torques of the four motors, perform calculation by using a preset overall vehicle dynamics model and a preset tire model according to driving torques of four wheels of the electric vehicle in a current state and the yaw moment difference ΔM to obtain a first opposite yaw moment, and perform the yaw control on the electric vehicle according to the first opposite yaw moment to calibrate an attitude of the electric vehicle; and
when the yaw control is performed on the electric vehicle by using the driving torques and the feedback braking torques of the four motors and using braking torques of the four hydraulic brakes simultaneously, perform calculation by using the preset overall vehicle dynamics model and the preset tire model according to the driving torques of the four wheels, braking torques of the four wheels of the electric vehicle in the current state and the yaw moment difference ΔM to obtain a second opposite yaw moment and to enable the electric vehicle to enter a stable state;
wherein braking torques of the four wheels at a moment are obtained according to feedback braking torques of the four motors at the moment and braking torques of the four hydraulic brakes at the moment, and driving torques of the four wheels at the moment are obtained according to driving torques of the four motors at the moment.

6. The active safety control system of an electric vehicle according to claim 5 , wherein the active safety controller is further configured to:
if a required braking torque of the yaw control is less than or equal to a braking torque formed by the feedback braking torques of the four motors, obtain the required braking torque by using the feedback braking torques of the four motors completely;
if the required braking torque of the yaw control is greater than the braking torque formed by the feedback braking torques of the four motors, obtain the required braking torque by using the feedback braking torques of the four motors and using the braking torques of the four hydraulic brakes simultaneously.

7. The active safety control system of an electric vehicle according to claim 4 , wherein when the electric vehicle is in a right-turn understeer state and front wheels of the electric vehicle have a side slip, the active safety controller is further configured to:
if the yaw angular speed difference Δψ′ is greater than the first preset angular speed and is less than or equal to the second preset angular speed, control a motor corresponding to a left-rear wheel of the four wheels by using the motor controller to increase a driving torque of the motor corresponding to the left-rear wheel; and
if the yaw angular speed difference Δψ′ is greater than the second preset angular speed, control the motor corresponding to the left-rear wheel by using the motor controller to increase the driving torque of the motor corresponding to the left-rear wheel, and simultaneously perform braking control on a right-rear wheel of the four wheels.

8. The active safety control system of an electric vehicle according to claim 4 , wherein when the electric vehicle is in a left-turn understeer state and f

Assignees

• Byd Co Ltd

Inventors

• Lian Yubo
• Luo Hongbin
• Zhang Jintao
• Yang Dongsheng

Classifications

• B60K7/0007

  the motor being electric · CPC title

• B60K17/356

  having fluid or electric motor, for driving one or more wheels · CPC title

• B60K17/043

  Transmission unit disposed in on near the vehicle wheel, or between the differential gear unit and the wheel · CPC title

• B60L7/18

  Controlling the braking effect (B60L7/12, B60L7/14, B60L7/16 take precedence) · CPC title

• B60L7/26

  Controlling the braking effect · CPC title