Anti-lock braking system and control method thereof

Patent metadata

Field	Value
Publication number	US-11613237-B2
Application number	US-202017030180-A
Country	US
Kind code	B2
Filing date	Sep 23, 2020
Priority date	Sep 23, 2020
Publication date	Mar 28, 2023
Grant date	Mar 28, 2023

Abstract

An Anti-lock Braking System and control method are disclosed. The control method is performed after a control module intervenes a vehicle's braking system and comprises: receiving a wheel speed signal of a wheel and a vehicle acceleration signal; computing a tire-slip feedback value according to the wheel speed signal of the wheels and the vehicle acceleration signal; generating a feedback control voltage according to a tire-slip difference between a tire-slip target value and the tire-slip feedback value; generating a tire-slip compensation value by performing a differential compensation to the tire-slip feedback value; obtaining a feedforward voltage according to the tire-slip compensation value via a look-up table approach; generating a braking control voltage by adding the feedback control voltage to the feedforward voltage; and outputting the braking control voltage to a proportioning-valve brake, such that the proportioning-valve brake adjusts a braking pressure according to the braking control voltage.

First claim

What is claimed is:

1. An Anti-lock Braking System adapted to a vehicle with multiple wheels and comprising:
an accelerometer outputting a vehicle acceleration signal reflecting acceleration of the vehicle;
multiple wheel speed sensors respectively corresponding to the multiple wheels and each one of the wheel speed sensors outputting a wheel speed signal;
multiple proportioning-valve brakes respectively corresponding to the multiple wheels and each one of the proportioning-valve brakes receiving a braking control voltage to adjust a braking pressure of each one of the wheels according to a magnitude of the braking control voltage; and
a control module electrically connected to the accelerometer, the wheel speed sensors, and the proportioning-valve brakes; wherein after the control module intervenes a braking system of the vehicle, the control module generates the braking control voltages for the proportioning-valve brakes respectively according to the vehicle acceleration signal and the wheel speed signals;
wherein the control module computes a tire-slip feedback value according to the wheel speed signal of each one of the wheel speed sensors and the vehicle acceleration signal, generates a feedback control voltage according to a tire-slip difference between a tire-slip target value and the tire-slip feedback value, generates a tire-slip compensation value by performing a differential compensation to the tire-slip feedback value, obtains a feedforward voltage according to the tire-slip compensation value via a look-up table approach, and generates the braking control voltage by adding the feedback control voltage to the feedforward voltage.

2. The Anti-lock Braking System of claim 1 , wherein
the control module stores multiple look-up tables for performing the look-up table approach;
each one of the look-up tables includes a voltage lower limit, a voltage upper limit, a tire-slip lower-limit, and a tire-slip upper limit;
when the tire-slip compensation value is between the tire-slip lower limit and the tire-slip upper limit, the tire-slip compensation value is linearly and directly proportional to the feedforward voltage.

3. The Anti-lock Braking System of claim 2 , wherein
the multiple wheels of the vehicle are multiple front wheels and multiple rear wheels;
the multiple look-up tables are a first look-up table corresponding to the front wheels and a second look-up table corresponding to the rear wheels;
the tire-slip upper limit in the first look-up table is defined as a first tire-slip upper limit, the tire-slip upper limit in the second look-up table is defined as a second tire-slip upper limit, and the second tire-slip upper limit is lower than the first tire-slip upper limit.

4. The Anti-lock Braking System of claim 3 , wherein the tire-slip feedback value (Slip FB ) is represented as:

Slip
FB

=

V
est

-
W

V
est

wherein V est is the vehicle's speed and W is the wheel's speed computed from the wheel speed signal of each one of the wheel speed sensors.

5. The Anti-lock Braking System of claim 4 , wherein the tire-slip compensation value (Slip COMP ) is represented as:

Slip
COMP

=

Slip
FB

+

C
×

d
dt

⁢

(

Slip
FB

)

wherein C is a value of weight, 0≤C≤1, and C for the front wheels is higher than C for the rear wheels.

6. An anti-lock braking control method performed after a control module intervenes a braking system of a vehicle with multiple wheels and comprising:
receiving a wheel speed signal of each one of the wheels and a vehicle acceleration signal;
computing a tire-slip feedback value according to the wheel speed signal of each one of the wheels and the vehicle acceleration signal;
generating a feedback control voltage according to a tire-slip difference between a tire-slip target value and the tire-slip feedback value;
generating a tire-slip compensation value by performing a differential compensation to the tire-slip feedback value;
obtaining a feedforward voltage according to the tire-slip compensation value via a look-up table approach;
generating a braking control voltage by adding the feedback control voltage to the feedforward voltage; and
outputting the braking control voltage to a proportioning-valve brake, such that the proportioning-valve brake adjusts a braking pressure of each one of the wheels according to a magnitude of the braking control voltage.

7. The anti-lock braking control method of claim 6 , wherein
multiple look-up tables are adopted in the look-up table approach and each one of the look-up tables includes a voltage lower limit, a voltage upper limit, a tire-slip lower-limit, and a tire-slip upper limit; and
when the tire-slip compensation value is between the tire-slip lower limit and the tire-slip upper limit, the tire-slip compensation value is linearly and directly proportional to the feedforward voltage.

8. The anti-lock braking control method of claim 7 , wherein
the multiple wheels of the vehicle are multiple front wheels and multiple rear wheels;
the multiple look-up tables are a first look-up table corresponding to the front wheels and a second look-up table corresponding to the rear wheels;
the tire-slip upper limit in the first look-up table is defined as a first tire-slip upper limit, the tire-slip upper limit in the second look-up table is defined as a second tire-slip upper limit, and the second tire-slip upper limit is lower than the first tire-slip upper limit.

9. The anti-lock braking control method of claim 8 , wherein the tire-slip feedback value (Slip FB ) is represented as:

Slip
FB

=

V
est

-
W

V
est

wherein V est is the vehicle's speed and W is the wheel's speed computed from the wheel speed signal of each one of the wheels.

10. The anti-lock braking control method of claim 9 , wherein the tire-slip compensation value (Slip COMP ) is represented as:

Slip
COMP

=

Slip
FB

+

C
×

d

Assignees

• Automotive Res & Testing Ct

Inventors

• Lin Hsin-Chuan
• Chang Hsuan-Yung

Classifications

• B60T2230/02

  Side slip angle, attitude angle, floating angle, drift angle · CPC title

• B60T2250/04

  Vehicle reference speed; Vehicle body speed · CPC title

• B60T8/1761 Primary

  responsive to wheel or brake dynamics, e.g. wheel slip, wheel acceleration or rate of change of brake fluid pressure · CPC title

• B60T8/171

  Detecting parameters used in the regulation; Measuring values used in the regulation · CPC title

• B60T8/265

  for hydraulic brake systems · CPC title