Method for controlling a wiper motor

• US 20040075409A1
• Filed: 06/20/2003
• Published: 04/22/2004
• Est. Priority Date: 12/21/2000
• Status: Active Grant

• Current Assignee: Valeo Systemes D'Essuyage (Valeo SE)
• Original Assignee: Valeo Systemes D'Essuyage (Valeo SE)
• Inventors: Jackson, James, Hospital, Eric
• Granted Patent: US 7,019,477 B2
• Time in Patent Office: Days
• US Class Current: 318/443
• CPC Class Codes: B60S 1/08 electrically driven conjoint control of windscreen wiper motor and liquid supply of windscreen washer B60S1/482; conjoint control of windscreen wiper motor and means for cleaning parts o parts other than windscreens or front windows B60S1/56, B60S1/58, B60S1/606
• CPC Class Codes: B60S 1/185 with means for stopping or setting the wipers at their limit of movement
• CPC Class Codes: Y10S 318/02 Windshield wiper controls

Abstract

The invention concerns a method for controlling a wiper motor of a wiper device for a motor vehicle windshield. The invention also concerns a control unit implementing the inventive method and a wiper device for a motor vehicle windshield. The invention is characterized in that the control unit (20) produces a control of the electric motor (19) which powers a wiper blade (15) on a windshield sweeping between two end-of-travel zones. In each end-of-travel zone, there is a software end-of-travel stop which is moved by a predetermined value after each passage on the software stop, the latter always remaining in its test zone, thereby providing self-adaptation of the sweeping limits in time. The invention also enables to detect the presence of obstacles on the wiper blade path.

Claims

1. Method for controlling a wiper motor equipping a wiper device in order to drive at least one wiper blade moving across a windshield according to an alternating path between a first and second end-of-travel positions, characterized by consisting of:

during a first initialization step (S1-S8),

detecting the first and second end-of-travel stops (FdC1, FdC2) such as determined by the construction of the associated wiper device, then

determining from these first and second end-of-travel stops first (ZdT1) and second (ZdT2) end-of-travel test zones and in each of the test zones the position (A, B) of a software stop on which the blade changes wiping direction in normal operation;

during a normal operation step;

detecting the position of the wiper blade relative to the first and second end-of-travel test zones, in order to determine the change of wiping direction and

realization during at least one passage of the wiper blade in a test zone a variation of the position of its end-of-travel software stop,

such that self-adaptation of the wiping limits is produced in time as a function of mechanical use, play and other accidents.

2. Method according to claim 1, characterized in that, during the normal operational step, the situation of each end-of-travel test zone is calculated as a function of the detection of the docking of the physical end-of-travel stops.

3. Method according to claim 2, characterized in that a first limit of each end-of-travel zone is determined on the basis of the detection of the docking of an end-of-travel stop and by a second limit placed at a predetermined distance from the first limit.

4. Method according to one of the preceding claims, characterized in that the variation of the position of each software stop is performed via incrementation of a positive or negative pitch such that the software stop stays in the test zone.

5. Method according to claim 1, during normal operation, characterized in that it also consists of detecting the presence of an obstacle on an alternating path of the wiper blade outside of a test zone, while it comes from one end-of-travel test zone, then determining a sweeping stop (33).

6. Method according to claim 5, characterized in that it also consists of controlling a reverse return (34) of the wiper blade from a predetermined distance, then a stop (36) of a predetermined duration, and finally a return to the position (33) of the obstacle (32), at least a predetermined number of times.

7. Method according to claim 5, characterized in that it also consists of controlling, from the stop position (33) of the detection of an obstacle a reverse return (34, 37) of the wiper blade toward the end-of-travel test zone (1, 11) from where the blade came.

8. Method according to claim 6 or 7, characterized in that it also consists of next controlling an initialization step (S1-S8), such that the obstacle (32) placed in the wiper blade'"'"'s path is considered as a physical end-of-travel stop and permitting sweeping during the normal operation step according to degraded amplitude.

9. Method according to claim 1, during normal operation, characterized in that is also consists of detecting the presence of an obstacle in an end-of-travel test zone, then producing a stop sweeping command, then a return in the opposite sweeping direction.

10. Method according to claim 9, characterized in that is also consists of incrementing an obstacle detection counter in an end-of-travel test zone, then detecting when the counter reaches a predetermined value, then executing the first initialization step again.

11. Control unit for implementing the control method according to one of the preceding claims, characterized by including:

means (54, 56) of determining an end-of-travel test zone at a first sweeping end the input of which is connected to means (50) of detecting the docking of the wiper blade on a physical end-of-travel stop;

means (54, 56) of determining an end-of-travel test zone at a second sweeping end the input of which is connected to means (51) of detecting the docking of the wiper blade on a physical end-of-travel stop;

means (57-59) of determining the position of the end-of-travel stop in each end test zone;

means (61) of controlling the movement of a wiper motor;

such that the sweeping direction is reversed during each docking of a software end-of-travel stop and such that the position of each software end-of-travel stop is varied at the end of a determined sweeping, in order for the software end-of-travel stop to stay inside the test zone relative to the associated physical end-of-travel stop.

12. Control unit according to claim 11, characterized in that it also comprises means (53) of detecting the presence of an obstacle outside of an end-of-travel test zone (ZdT1, ZdT2), the output signal of which is transmitted to the activation input of a generator (60) that comprises, separately or in combination:

means of controlling a reverse return of the wiper blade from a predetermined distance, means of controlling a reverse return of the wiper blade until the preceding software end-of-travel stop, means producing a stop time of a predetermined duration, then a return towards the detected position of the obstacle, a counter of the number of detection of an obstacle from an intermediate stop position (36) producing an active output signal when the number of detections surpasses a predetermined value, such that the means of controlling a reverse return of the wiper blade until the preceding software end-of-travel stop is activated, the counter thus being reinitialized, a counter of the number of detections of obstacle from an end-of-travel test zone, producing an active output signal when the number of detections surpasses a predetermined value, such that at least one of the means of determining an end-of-travel test zone and a software end-of-travel stop are activated by taking the position of the obstacle (32) as end-of-travel stop.

13. Control unit according to claim 11 or 12, characterized in that it also comprises means (53) of detecting the presence of an obstacle in the end-of-travel test zone, the output signal of which is transmitted to the activation input of a generator (60) that controls a reverse return toward the opposite end-of-travel test zone.

14. Control unit according to claim 13, characterized in that it also comprises means (60) of counting the number (Tb) of sweepings during which an obstacle has been encountered, then when the predetermined number (Tbd) of sweepings has been reached, recalculating the situation of the end-of-travel test zone in which an obstacle has been detected.

15. Wiper device incorporating a wiper control unit according to one of claims 11 to 14 characterized in that it comprises a wiper motor (19) powered under the control of a control device (16) in order to detect a stop/start command of a user or of an on-board computer, connected to said wiper control unit (20), which also receives signals representative of the right and left physical ends-of-travel as well as the relative position and of the detection of an obstacle generated via detection means (22) in relation to the output shaft of the wiper motor (19), mechanically connected to a redactor (18) and to a conversion device (17) of the rotational movement of the output shaft of the redactor (18) in a sweeping movement applied to at least one wiper blade (15).