# US 5,344,223 A · Anti-skid brake control method

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- Number: US 5,344,223 A
- Document ID: US5344223A
- Status: Granted
- Kind: A
- Application number: 08/109,473
- Filed: 1993-08-20
- Granted: 1994-09-06
- Earliest claimed: 1991-05-16
- Assignees: Jidosha Kiki Co., Ltd.
- Inventors: Ryuta Sugawara; Satoshi Akimoto
- Web page: https://patentgrep.com/patent/US5344223A

## CPC

- B60T 8/1764: Regulation during travel on surface with different coefficients of friction, e.g. between left and right sides, mu-split {or between front and rear}
- B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES

## Abstract

In the present invention, an estimated car body speed is obtained on the basis of the highest wheel speed selected from three wheel speeds including the lowest of the wheel speeds of left and right rear wheels and the wheel speeds of left and right front wheels. Because the car body speed is obtained on the basis of wheel speed selected by Select-High of three channels of wheel speeds of the two front wheels and wheel speed by Rear Select-Low, wheel speed of outer rear wheel, which is much higher than the speed of the gravity center of the car body when a car is turning, is excluded, and the estimated car body speed thus obtained is closer to the speed of the gravity center of the car body.

## Claims

### Claim 1

A method for performing anti-skid brake control in a vehicle when the vehicle is turning, which comprises:
braking while turning said vehicle,
detecting when wheels of said vehicle are in a skid condition,
detecting wheel speeds of front and rear wheels of said vehicle,
comparing wheel speeds of said rear wheels and selecting a lowest rear wheel speed based thereon,
comparing wheel speeds of said front wheels and said lowest rear wheel speed and selecting a highest wheel speed based thereon,
estimating vehicle body speed based on said selected highest wheel speed, and
increasing and decreasing braking force on said wheels based on said estimated vehicle speed for stabilizing steering of said vehicle and shortening braking distance.

### Claim 2 (depends on 1)

The method for performing anti-skid brake control according to claim 1, wherein said wheel speeds of said front and rear wheels of said vehicle are detected at all times when performing said anti-skid brake control.

### Claim 3

A method for performing anti-skid brake control in a vehicle comprising:
(a) increasing braking force on front and rear wheels of said vehicle for stopping said vehicle,
(b) detecting wheel speeds of said front and rear wheels of said vehicle during braking,
(c) detecting when said wheels are in a skid condition,
(d) comparing wheel speeds of said rear wheels and selecting a lowest rear wheel speed,
(e) comparing only wheel speeds of said front wheels and said lowest rear wheel speed selected in step (d) and selecting a highest wheel speed based thereon, and
(f) estimating vehicle body speed based on said selected highest wheel speed of step (e),
(g) decreasing braking force on said front and rear wheels based on said estimated vehicle body speed to eliminate said skid condition, and
(i) again increasing braking force on front and rear wheels of said vehicle for stabilizing steering of said vehicle and for stopping said vehicle.

### Claim 4 (depends on 3)

The method for performing anti-skid brake control according to claim 3, wherein said vehicle is turning during said steps (a) through (i).

### Claim 5 (depends on 3)

The method for performing anti-skid brake control according to claim 3, wherein said lowest rear wheel speed selected in step (d) is an inner wheel relative to said turning of said vehicle.

### Claim 6 (depends on 3)

The method for performing anti-skid brake control according to claim 3, wherein said wheel speeds of said front and rear wheels of said vehicle are detected at all times when performing said anti-skid brake control.

### Claim 7

In a method for performing anti-skid brake control including detecting wheel speeds of a vehicle during braking, which includes estimating a vehicle body speed from the detected wheel speeds, obtaining a value of wheel skidding from the estimated vehicle body speed, and decreasing braking force to eliminate the wheel skidding and increasing braking force to stabilize steering of the vehicle and shorten braking distance, wherein the improvement comprises the estimating of the vehicle body speed by the following steps:
detecting when wheels of the vehicle are in a skid condition,
detecting wheel speeds of front and rear wheels of the vehicle,
comparing wheel speeds of the rear wheels and selecting a lowest rear wheel speed based thereon,
comparing wheel speeds of the front wheels and the lowest rear wheel speed and selecting a highest wheel speed based thereon, and
estimating vehicle body speed based on the selected highest wheel speed.

### Claim 8 (depends on 7)

The method for performing anti-skid brake control according to claim 7, wherein the vehicle is turning when while carrying of the steps of the estimating of the vehicle body speed.

### Claim 9 (depends on 7)

The method for performing anti-skid brake control according to claim 7, wherein said wheel speeds of said front and rear wheels of said vehicle are detected at all times when performing said anti-skid brake control.