BRAKE CONTROLLER

Abstract

A brake controller is provided that includes a braking force application mechanism that presses a friction member against a braked member so as to apply a braking force to a wheel of a vehicle; and a control unit. The control unit calculates an index, which indicates a difference between an expected braking effectiveness and an actual braking effectiveness, corrects a target value, which is set to control a pressing force of the friction member, in accordance with the index to reduce a variation in a braking effectiveness of the vehicle. The control unit further sets a variation range in accordance with a factor that causes the difference. The variation range limits a variation in a correction amount to correct the target value.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and further objects, features and advantages of the invention will become apparent from the following description of preferred embodiments with reference to the accompanying drawings, wherein like numerals are used to represent like elements and wherein:

FIG. 1 shows a schematic view of a brake controller according to an embodiment of the present invention;

FIG. 2 shows a control block diagram according to the embodiment of FIG. 1;

FIG. 3 shows a flowchart indicating an example of control process for the braking force in the embodiment of FIG. 1;

FIG. 4 shows a flowchart indicating an example of learning process for the braking effectiveness in the embodiment of FIG. 1;

FIG. 5 is a flowchart illustrating an example of a process when the vehicle weight changes, according to the embodiment of the present invention;

FIG. 6 a view illustrating an example of the variation range of the braking effectiveness correction coefficient when the vehicle weight increases or decreases; and

FIG. 7 is a view illustrating an example of relationship between the correction coefficient and the variation range.

Claims

1. A brake controller, comprising: a braking force application mechanism that presses a friction member against a braked member to apply a braking force to a wheel of a vehicle; anda control unit that calculates an index that indicates a difference between an expected braking effectiveness and an actual braking effectiveness, corrects a target value, which is set to control the pressing force of the friction member, in accordance with the index to reduce variation in braking effectiveness of the vehicle, and sets a variation range in accordance with a factor that causes the difference, wherein the variation range limits variation in a correction amount to correct the target value.

2. The brake controller according to claim 1, wherein the control unit sets the variation range so that the variation in the correction amount necessary to compensate for a long-term increase in the difference between the expected braking effectiveness and the actual braking effectiveness is within the variation range.

3. The brake controller according to claim 1, wherein the control unit accepts the variation in the correction amount that exceeds the variation range, when the difference between the expected braking effectiveness and the actual braking effectiveness is increased by a temporary factor that arises in the course of using the vehicle.

4. The brake controller according to claim 1, wherein the control unit expands the variation range, when the difference between the expected braking effectiveness and the actual braking effectiveness is increased by a temporary factor that arises in the course of using the vehicle.

5. The brake controller according to claim 4, wherein the control unit detects an increase in a vehicle weight as the temporary factor, and sets a larger variation range after the increase in the vehicle weight is eliminated, as compared with the variation range before the increase in the vehicle weight.

6. The brake controller according to claim 1, wherein, when the index suddenly exceeds a predetermined reference value, the control unit determines that the factor is a change in a vehicle weight.

7. The brake controller according to claim 1, wherein the braking force application mechanism presses the friction member to the braked member by supplying a hydraulic fluid, the control unit calculates an actual hydraulic pressure deceleration caused by the braking force application mechanism from a measured deceleration of the vehicle, calculates an estimated hydraulic pressure deceleration using a hydraulic pressure supplied by the braking force application mechanism, and corrects the target value in accordance with a difference between the estimated hydraulic pressure deceleration and the actual hydraulic pressure deceleration

8. The brake controller according to claim 1, wherein the control unit changes the correction amount to a preset value when a sudden change in the actual braking effectiveness is expected.

9. The brake controller according to claim 8, wherein the control unit resets the correction amount to an initial value.

10. The brake controller according to claim 8, wherein the control unit changes the correction amount so that the correction amount approaches an initial value.

11. The brake controller according to claim 8, wherein the control unit changes the correction amount if a maintenance operation is detected.

12. The brake controller according to claim 1, wherein the control unit changes the variation range of the correction amount in accordance with a variation in a tire diameter.

13. The brake controller according to claim 1, wherein the control unit sets a wider variation range when the factor is a temporary factor, as compared with when the factor is a long-term factor, the temporary factor and the long-term factor respectively causing the difference in a short term and a long term bases.

14. A brake controller, comprising: a braking force application mechanism that applies a braking force to a wheel of a vehicle by pressing a friction member to a braked member; anda control unit that calculates an index that indicates a difference between an actual braking effectiveness and a target braking effectiveness, calculates a correction amount of a target value, which is set to control a pressing force of the friction member, in accordance with the index, sets a variation range of the correction amount in accordance with a factor that causes the difference, adjusting the calculated correction amount to be within the variation range, and corrects the target value using the adjusted calculated correction amount to reduce a variation in the actual braking effectiveness.