Foundation brake control algorithm for electro-hydraulic brake system and brake-by-wire system

• US 6,226,586 B1
• Filed: 08/24/1999
• Issued: 05/01/2001
• Est. Priority Date: 03/06/1997
• Status: Expired due to Term

• Current Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Kelsey-Hayes Co. (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Luckevich, Mark S., Kingston, Andrew W.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): MANCHO, RONNIE M
• Application Number:
  US09/379,881
• Time in Patent Office: 616 Days
• Field of Search: 303/10, 303/15, 303/20, 303/155, 188/72.1, 188/72.4, 701/83, 701/110
• US Class Current: 701/70
• CPC Class Codes: B60T 13/16 using pumps directly, i.e. without interposition of accumulators or reservoirs
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 13/74 with electrical assistance or drive
• CPC Class Codes: B60T 17/221 Procedure or apparatus for checking or keeping in a correct functioning condition of brake systems hydraulic pressure systems in general F15B19/00, F15B21/04; testing structures or apparatus G01M
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/3255 Systems in which the braking action is dependent on brake pedal data
• CPC Class Codes: B60T 8/326 Hydraulic systems
• CPC Class Codes: B60T 8/4072 Systems in which a driver input signal is used as a control signal for the additional fluid circuit which is normally used for braking

Abstract

A brake control system determines utilizes a sensed amount of brake travel and a sensed amount of master cylinder pressure in determining a base brake control signal for an electro-hydraulic brake management system. The system also provides a springer function to provide an appropriate amount of brake jump-in, based on vehicle velocity and pedal travel. For pure brake-by-wire systems that have no hydraulic components, brake force is substituted for master cylinder pressure in determining a base brake control signal.

Claims

1. An apparatus for determining a total amount of brake jump-in for a vehicle during brake application, comprising:

a first input port for receiving a first signal that is indicative of vehicle speed;

a second input port for receiving a second signal that is indicative of brake pedal travel; and

a control unit for determining a first component of a brake command signal based upon the second signal and for determining a total amount of brake jump-in based on the first and second signals, the jump-in forming a second component of the brake command signal resulting in a step increase of the brake command signal after an initial amount of pedal travel.

2. An apparatus according to claim 1, wherein the control unit comprises:

a memory for storing a first gain value and a first offset value that are used in determining a first amount of jump-in that is to be provided based on the first signal, and for storing a second gain value and a second offset value that are used in determining a second amount of jump-in that is to be provided based on the second signal; and

a multiplier for multiplying the first and second amounts of jump-in to obtain the total amount of jump-in for the vehicle.

3. An apparatus for providing a brake control signal P_BBC, comprising:

a first sensor for sensing an amount of travel of a brake pedal, said first sensor generating an output Ped_Travel;

a second sensor for sensing one of an amount of master cylinder pressure or force exerted upon the brake pedal, said second sensor generating an output P_—

2; and

a control circuit for providing the brake control signal based on the outputs of the first and second sensors, the control circuit determining a first command signal based on the output of the first sensor according to the equation $P_{\mathrm{cmd\_travel}}=\left[\left(\mathrm{Ped\_Travel}-\mathrm{Ped\_Travel}<br><br>\mathrm{\_Min}\right)*K_1+{\left(\mathrm{Ped\_Travel}-\mathrm{Ped\_Travel}<br><br>\mathrm{\_Min}\right)}^2*K_2\right],$

the control circuit determining a second command signal based on the output of the second sensor according to the equation $P_{\mathrm{cmd\_P}<br><br>\_<br><br>2}=\left[\left(\mathrm{P\_}<br><br>2-\mathrm{P\_}<br><br>2<br><br>\mathrm{\_min}\right)*K_3+{\left(\mathrm{P\_}<br><br>2-\mathrm{P\_}<br><br>2<br><br>\mathrm{\_min}\right)}^2*K_4\right],$

where P_—

2_min is a constant value indicative of a minimum value of P_—

2, the control circuit determining a blending term according to the equation

4. A method of providing a brake pressure control signal, comprising the steps of:

sensing an amount of travel of a brake pedal;

sensing an amount of master cylinder pressure;

determining a first component of a brake pressure control signal based on the sensed amount of travel;

determining a second component of the brake pressure control signal based on the sensed amount of master cylinder pressure; and

determining, as a third component of the brake pressure control signal a rate of change of the second component of the brake pressure control signal over a period of time,

wherein the brake pressure control signal is based on the first component, the second component, and the third component.

5. A method according to claim 4, wherein the brake pressure control signal is based on a weighting for the first and second components, and a total amount of the third component.

6. A method of providing a brake control signal, comprising the steps of:

sensing an amount of travel of a brake pedal;

sensing an amount of master cylinder pressure;

determining, based on the sensed amount of travel, a first weighting value that is used to determine a contribution of pressure required from the sensed amount of travel; and

determining, based on the sensed amount of travel and not on the sensed master cylinder pressure, a second weighting value that is used to determine a contribution of pressure required from the sensed master cylinder pressure, wherein the first weighting value added to the second weighting value is equal to one.

7. An apparatus for determining a total amount of brake jump-in for a vehicle during brake application, comprising:

a first input port for receiving a first signal that is indicative of vehicle speed;

a second input port for receiving a second signal that is indicative of brake pedal travel; and

a control unit for determining the total amount of brake jump-in based on the first and second signals, the control unit comprising;

a memory for storing a first gain value and a first offset value that are used in determining a first amount of jump-in that is to be provided based on the first signal, and for storing a second gain value and a second offset value that are used in determining a second amount of jump-in that is to be provided based on the second signal; and

a multiplier for multiplying the first and second amounts of jump-in to obtain the total amount of jump-in for the vehicle.

8. A method of providing a brake pressure control signal, comprising the steps of:

sensing an amount of travel of a brake pedal;

sensing an amount of force applied to the brake pedal;

determining a first component of a brake pressure control signal based on the sensed amount of travel;

determining a second component of the brake pressure control signal based on the sensed amount of force applied to the brake pedal; and

determining, as a third component of the brake pressure control signal a rate of change of the second component of the brake pressure control signal over a period of time,

wherein the brake pressure control signal is based on the first component, the second component, and the third component.

9. An apparatus for providing a brake control signal for a vehicle, comprising:

a first sensor for sensing an amount of travel of a brake pedal;

a second sensor for sensing vehicle speed

a third sensor for sensing an amount of force applied to the brake pedal; and

a control unit for providing the brake control signal based on the outputs of the first and third sensors, as modified by the outputs of the first and second sensors to provide jump-in, the jump-in forming a component of the brake control signal resulting in a step increase of the brake control signal after an initial amount of pedal travel.