Method for proportionally controlling the brakes of a vehicle based on tire deformation

• US 5,646,848 A
• Filed: 08/09/1995
• Issued: 07/08/1997
• Est. Priority Date: 08/09/1995
• Status: Expired due to Fees

• Current Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Thatcher, David Alan, Leppek, Kevin Gerard, Walenty, Allen John
• Primary Examiner(s): ZANELLI, MICHAEL J
• Application Number:
  US08/513,192
• Time in Patent Office: 699 Days
• Field of Search: 364/426.01, 303/9.62, 303/155, 303/167, 303/169, 303/186
• US Class Current: 701/70
• CPC Class Codes: B60T 2240/04 Tire deformation
• CPC Class Codes: B60T 8/1725 Using tyre sensors, e.g. Sidewall Torsion sensors [SWT] for tyre pressure and temperature detection B60C23/00
• CPC Class Codes: B60T 8/1766 Proportioning of brake forces according to vehicle axle loads, e.g. front to rear of vehicle
• CPC Class Codes: B60T 8/267 for hybrid systems with different kind of brakes on different axles

Abstract

A method of brake control, comprising the steps of: determining a deceleration of a vehicle; measuring a first wheel rotational velocity of a front wheel of the vehicle; measuring a second wheel rotational velocity of a rear wheel of the vehicle; determining a front wheel normalization value responsive to the deceleration and a front tire deformation constant; determining a rear wheel normalization value responsive to the deceleration and a rear tire deformation constant; determining a front normalized wheel rotational velocity responsive to the front wheel normalization value and the first wheel rotational velocity, wherein the front normalized wheel rotational velocity is responsive to a front tire deformation that occurs during a braking maneuver of the vehicle; determining a rear normalized wheel rotational velocity responsive to the rear wheel normalization value and the second wheel rotational velocity, wherein the rear normalized wheel rotational velocity is responsive to a rear tire deformation that occurs during a braking maneuver of the vehicle; subtracting the front normalized wheel rotational velocity from the rear normalized wheel rotational velocity to determine a difference; and adjusting front to rear brake proportioning responsive to the difference, wherein front to rear brake proportioning is responsive to tire deformation that occurs during a braking maneuver.

Claims

1. A method of brake control, comprising the steps of:

determining vehicle deceleration;

multiplying the vehicle deceleration by a front tire deformation constant to determine a front tire deformation increment;

multiplying the vehicle deceleration by a rear tire deformation constant to determine a rear tire deformation increment;

determining an updated front tire normalization value by subtracting the front tire deformation increment from a previous front tire normalization value;

determining an updated rear tire normalization value by adding the rear tire deformation increment to a previous rear tire normalization value;

measuring at least one front wheel speed and at least one rear wheel speed;

determining an adjusted front wheel speed by multiplying the measured front wheel speed by the updated front tire normalization value;

determining an adjusted rear wheel speed by multiplying the measured rear wheel speed by the updated rear tire normalization value;

determining a dynamic proportioning adjustment responsive to the adjusted front and rear wheel speeds; and

controlling brakes for the front and rear wheels responsive to the dynamic proportioning adjustment.

2. A method of brake control comprising:

receiving an operator-input brake command;

determining front and rear brake commands responsive to the operator-input brake command;

measuring wheel speed;

determining vehicle deceleration;

determining a dynamic proportioning adjustment responsive to the measured wheel speed, the vehicle deceleration and a tire deformation constant;

adjusting at least one of;

(a) the from brake command and (b) the rear brake command in response to the dynamic proportioning adjustment; and

controlling vehicle brakes according to the front and rear brake commands.

3. A method of brake control, comprising the steps of:

determining a deceleration of a vehicle;

measuring a first wheel rotational velocity of a front wheel of the vehicle;

measuring a second wheel rotational velocity of a rear wheel of the vehicle;

determining a front wheel normalization value responsive to the deceleration and a front tire deformation constant;

determining a rear wheel normalization value responsive to the deceleration and a rear tire deformation constant;

determining a front normalized wheel rotational velocity responsive to the front wheel normalization value and the first wheel rotational velocity, wherein the front normalized wheel rotational velocity is responsive to a front tire deformation that occurs during a braking maneuver of the vehicle;

determining a rear normalized wheel rotational velocity responsive to the rear wheel normalization value and the second wheel rotational velocity, wherein the rear normalized wheel rotational velocity is responsive to a rear tire deformation that occurs during a braking maneuver of the vehicle;

subtracting the front normalized wheel rotational velocity from the rear normalized wheel rotational velocity to determine a difference;

adjusting front to rear brake proportioning responsive to the difference, wherein front to rear brake proportioning is responsive to tire deformation that occurs during a braking maneuver.

4. A brake control method according to claim 3, wherein the step of adjusting front to rear brake proportioning comprises the step of:

multiplying the difference by a rear brake command to determine a modified rear brake command, wherein, commanded rear brake torque is reduced.

5. A brake control method according to claim 3, wherein the rear tire deformation constant has a first magnitude greater than a second magnitude of the front tire deformation constant, indicating a first rate of tire deformation of the rear wheel greater than a second rate of tire deformation of the front wheel.