FR2757467A1 - Windscreen wiper blade control system for varying conditions - Google Patents

Abstract

The windscreen wiper includes a drive motor (1) for movement of the arm (2) which supports the blade (3) of the wiper. A control (4) is provided to regulate the force with which the blade is applied against the windscreen glass. A further control (5) is provided to control the inclination of the blade w.r.t. the glass during its operation. The operating conditions of the wiper blade are detected in order to determine the optimum settings for these parameters in order to achieve the most effect wiping action. The conditions detected include the speed of the vehicle, the aerodynamic pressure on the screen, a rain detector, and a second determining the resistive couple experienced by the drive mechanism. Further detectors sense the force with which the blade is applied to the screen, and the angle of approach.

Description

 The present invention relates to a system for controlling the operation of a wiper mechanism of a motor vehicle.

 Generally, such a wiper mechanism comprises means for driving at least one support arm of at least one wiper squeegee.

 These drive means generally consist of an electric gearmotor associated with an operating linkage of the support arm of the squeegee to cause the latter to wipe the window according to a particular scanning cycle.

 The gearmotor is in fact controlled by means of controlling its power supply making it possible, for example, to operate it intermittently, at low speed or at high speed, under the control of activation means which can be controlled by a user.

 However, such a system has a number of drawbacks, since it does not allow the operation of the wiper mechanism to be adapted to the operating conditions thereof.

 It has also been proposed in the state of the art, to use means making it possible to vary the pressing force of the squeegee on the window during its operating cycle.

 In the state of the art, these means comprise for example a spring for biasing the squeegee support arm.

 However, such means prove insufficient to optimize the wiping of the window regardless of the conditions of use of the mechanism.

 The object of the invention is therefore to solve these problems by proposing a system for controlling the operation of a windscreen wiper mechanism of a motor vehicle, which is simple, reliable and which makes it possible to optimize the operation thereof. whatever the operating conditions encountered.

To this end, 1 invention relates to a system for controlling the operation of a wiper mechanism of a motor vehicle, characterized in that it comprises
means for driving at least one support arm of at least one wiper blade,
means for adjusting the pressing force of said squeegee on the window,
means for controlling the inclination of said squeegee relative to the window,
means for reading the operating conditions of the wiper mechanism, and
means of analysis of these operating conditions to determine optimal control parameters of the different means of the wiper mechanism and of piloting these different means from these control parameters to optimize the operation of the latter.

The invention will be better understood on reading the description which follows, given solely by way of example and made with reference to the accompanying drawings, in which
- Fig.1 shows a block diagram illustrating the general structure of a wiper mechanism forming part of a system according to the invention;
- Fig.2 shows a block diagram of an electrical circuit of a first embodiment of a control system according to the invention;
- Fig.3 shows a block diagram of an electrical circuit of a second embodiment of a control system according to the invention;
- Fig.4 illustrates the different information used in a control system according to the invention;
- Fig.5 shows a curve illustrating the operation of means for controlling the inclination of a squeegee forming part of a control system according to the invention;
- Fig.6 shows a curve illustrating the operation of means for adjusting the pressing force of a squeegee, forming part of a control system according to 1 invention; and
- Figs. 7 and 8 represent curves illustrating the signature of the inversion of a wiper blade blade, in the case of a good inversion for FIG. 7 and in the case of a bad inversion for FIG. 8.

 There is shown very schematically in Figure 1, the general structure of an exemplary embodiment of a wiper mechanism of a motor vehicle.

 Generally, such a mechanism comprises means designated by the general reference 1 for driving at least one support arm designated by the general reference 2, at least one wiper blade, designated by the general reference 3 .

 In this respect, it will be noted that an operating linkage is interposed for example between the drive means 1 which may include an electric motor and the squeegee support arm designated by the general reference 2.

 This structure being well known in the state of the art, it will not be described in more detail below.

 Furthermore, means 4 for adjusting the pressing force of the squeegee 3 on the glass can also be envisaged.

 These means can also include an electric motor associated through any linkage, to the support arm 2 to ensure an adjustment of the pressing force of the squeegee on the window according to the command applied to it.

 Finally, in such a mechanism, it is also possible to provide means for controlling the inclination or angle of incidence of the squeegee relative to the window.

 These means are designated by the general reference 5 in this figure and also include, for example, an electric motor connected by means of any other linkage, to the support arm 2 to allow the tilting thereof to be controlled and therefore of the squeegee, relative to the glass, for example by pivoting of the support arm.

 In the embodiment shown in this FIG. 1, a single scraper 3 is carried by the support arm 2.

 It goes without saying of course that a different number of squeegees can be carried by this support arm in a conventional manner.

 Finally, it will also be noted that different structures of the wiper mechanism can be envisaged, this being able to be associated with the windshield or with the rear window of the vehicle.

 These may in fact include mechanisms with parallel scanning, non-circular parallel scanning, antagonistic scanning also called butterfly scanning, comprising a single brush operating in a circular or non-circular manner or even a single pantograph brush.

 It will easily be understood that in these different cases, one or more motors for driving one or more support arms carrying one or more wiper blades can be envisaged.

 The purpose of the control system according to the invention is to optimize and maintain the quality of wiping of the window whatever the operating and use conditions of the wiper mechanism.

 In this case, and as will be described in more detail below, an information processing unit of the system receives information concerning various parameters acting on the quality of wiping and, as a function of these, determines the parameters. for controlling the various means of the mechanism to ensure the control of their operation in order to optimize the operation of the wiper mechanism.

 Such optimization is carried out in real time automatically and continuously, while the wiper mechanism is activated. This then makes it possible to maintain an optimal wiping quality.

 The parameters on which it is possible to act to optimize this wiping are the pressing force of the squeegee on the glass, the angle of incidence of the latter relative to the glass, the speed and the acceleration of scanning and possibly, if necessary, the intermittence delay.

 This then makes it possible, for example, to reduce the size of the wiper mechanism, to reduce the wiping noises, to limit the wear of the squeegees, to eliminate the squeegee twists, to reduce the electrical consumption of the control motors. , to ensure that the driver or user actuates the mechanism control as little as possible in order to increase the driving pleasure of the vehicle, to preserve the wiper mechanism in the event of obstruction of the area d 'wiping and have a scanning speed always adapted to the amount of water falling on the glass, that is to say in fact on the windshield or on the rear window of the vehicle.

 There are shown in Figures 2 and 3, two embodiments of a control system according to the invention.

 FIG. 2 represents the case of a wiper mechanism comprising a single motor for driving a support arm of a wiper blade of a vehicle windshield, while FIG. 3 represents the case a mechanism comprising two motors for driving two arms for supporting the wiper squeegees of this windshield.

 In general, such a control system therefore makes it possible to control the operation of a windscreen wiper mechanism of a motor vehicle which comprises at least one motor 10 for driving a support arm of a wiper blade for the vehicle windshield, a motor 11 for driving a support arm for a wiper blade for the rear window of the vehicle, a motor 12 for adjusting the bearing force of the corresponding squeegee on the corresponding window of the vehicle and a motor 13 for adjusting the angle of incidence of the corresponding squeegee relative to the corresponding window.

 Furthermore, this control system also comprises means for reading the operating conditions of the wiper mechanism, these reading means being designated by the general reference 14 in these figures.

 These reading means are connected to means 15 for analyzing these operating conditions in order to determine parameters for optimal control of the different means of the wiper mechanism, described above and for controlling these different means from these parameters. to optimize the functioning of this mechanism.

 The means for reading the operating conditions of the mechanism may include a certain number of sensors, detectors or other measuring devices making it possible in particular to read the speed of the vehicle, the aerodynamic pressure, the quantity of water falling on the window, the resistant torque. at the level of the drive motor, the angular position of this motor or of the mechanism in general, which makes it possible to obtain by derivation the speed and acceleration of the latter, the electric consumption of this motor, the force of support of the squeegee on the window, the angle of incidence of the latter relative to the window and the state of the activation means operable by the user.

 These different reading means are shown in these Figures 2 and 3, and designated by the general reference 14, as indicated above.

 In these figures, the vehicle speed sensor is designated by the general reference 16, the aerodynamic pressure sensor is designated by the general reference 17, the rain sensor is designated by the general reference 18, the resistant torque sensor is designated by the general reference 19, the angular position sensor is designated by the general reference 20, the device for measuring the intensity consumed by the or each drive motor is designated by the general reference 21, the force sensor support is designated by the reference 22, the angle of attack sensor is designated by the general reference 23 and finally, the state sensor of the activation means operable by the user, is designated by the general reference 24.

 As shown, these various sensors can for example be connected via an information transmission network of any suitable type, designated by the general reference 25, to the analysis and control means 15 described above.

 These include, for example, a line interface 26, a protocol manager 27 and an information processing unit generally designated by the reference 28, the output of which controls the various motors 10, 11, 12 and 13 described above. , to control them, in order to optimize the operation of the wiper mechanism by adapting it to the conditions encountered.

 Indeed, and as indicated above, this unit 28 of the analysis and control means makes it possible to analyze the operating conditions of the wiper mechanism from information coming from the reading means 14 to determine optimal control parameters for the various means of the latter in order to control them accordingly.

 These analysis and control means can be integrated into a computer already installed in certain vehicles, to limit the additional cost of this function.

 These analysis means can be adapted to determine the optimal control parameters from pre-established operating tables of the mechanism and stored in memory means or to calculate them using means for modeling the operation of the mechanism, also stored. in storage means.

 It can therefore be seen, as can be seen in FIG. 4, that the various sensors, detectors or the like, described with reference to FIGS. 2 and 3, make it possible to deliver to the processing unit 28 analysis and control means, the different information necessary for them to regulate the operation of the different means of the wiper mechanism, for example by varying the bearing force of the squeegee on the corresponding window, the angle of incidence thereof with respect to the glass, and / or the scanning speed, in order to obtain in particular a good squeegee overturning and a good wiping of the glass.

 Also conventionally, the activation means which can be actuated by the user may include stop positions 0, automatic operation AUTO associated with the rain sensor, low speed PV and high speed scanning GV.

 As indicated above, the analysis and control means can operate from means for modeling the operation of the mechanism stored in storage means of the information processing unit to determine the parameters of optimal control.

 These modeling means can then be presented, for example, in the form of mathematical equations which make it possible to optimize the wiping quality with respect to a mathematical criterion based on the turning or non-turning of the squeegee blade at each end of scanning, on the pressing force of the squeegee and on the angle of incidence of the squeegee relative to the corresponding window.

 It is therefore possible at any time during the scanning cycle of the window to determine the parameters for optimal control of the mechanism from the different information delivered by the different sensors described above.

 It is then very simple to determine and optimize in real time the angle of incidence of the squeegee during the sweeping cycle to help the turning over and eliminate the risks of twisting of the squeegee blade during this sweeping cycle. sweeping due in particular to a poor reversal thereof, but also as a function of the curve of the corresponding window.

 It is also possible to determine and optimize in real time the speed and the acceleration of the squeegee scanning by the control of the drive motor, during the scanning cycle and in particular around the fixed stop and opposite fixed stop positions. of the cycle to favor the turning of the squeegee.

 It is also possible to determine and optimize the angle of incidence and the pressing force in real time in order to ensure good reversal of the squeegee blade, in particular at the fixed stop and opposite fixed stop positions of the scanning cycle. to eliminate the risk of twisting the squeegee blade during it.

 Finally, it is also possible to determine and optimize in real time, the angle of incidence, the pressing force and the speed and acceleration of the drive motor during the scanning cycle in order to ensure good turning of the squeegee blade and good wiping quality of the glass.

 In general, the analysis and control means thus make it possible to independently control one or more of the control parameters or to act on any possible combination of these to optimize the wiping quality of the mechanism.

 The control parameters are then applied in real time by the analysis and control means to the corresponding means of the mechanism, that is to say for example to the motors thereof.

 The analysis and control means may include a specific microcomputer or be integrated into a microcomputer already installed in the vehicle.

 These means then receive the information from the sensors concerning the operating conditions of the wiper and determine new values of the control parameters for controlling the various means of the mechanism.

 In the case where the mechanism includes drive means in the form of an electric motor, this may include a gear motor with alternating, rotary or other output.

 This motor is therefore controlled by the analysis and control means in terms of speed and torque to drive the squeegee support arm by means or not of a crankshaft mechanism.

 In addition, it sends back to the analysis and control means, via the information transmission network, the information concerning the intensity consumed.

 The means for adjusting the pressing force may also include an electric motor which may be in the form of a reversible stepping motor or of another actuator with relatively precise evolution.

 This motor is controlled by the analysis and control means to vary the bearing force of each corresponding squeegee on the glass and returns via the information transmission network, to the analysis and control means, the information concerning this support force.

 The means for adjusting the angle of incidence may also include a reversible stepping motor or another actuator with relatively precise evolution.

 This is controlled by the analysis and control means to vary the angle of incidence of the squeegee relative to the window and returns via the information transmission network, to the analysis and control means , the information concerning this angle of incidence.

 The resistive torque sensor associated with the drive motor or with the mechanism in general, informs the analysis and control means of the value of the resistive torque at the level thereof.

 This torque information associated with the intensity information consumed by the motor makes it possible to determine the presence of an obstacle on the window and the coefficient of friction of the squeegee thereon.

 Depending on the value of this signal, it detects or not the correct reversing of the squeegee, as will be described in more detail below.

 The support force sensor can in turn be in the form of a potentiometer or the like which can be integrated into the support force control motor.

 This then informs the analysis and control means of the value of the instantaneous pressing force of the squeegee on the glass to allow the control of this engine and returns this control information to the analysis and ordered.

 The angle-of-attack sensor for the squeegee on the window may in turn be in the form of an evaluation software sensor, a potentiometer or the like, which can be integrated into the corresponding motor.

 The sensor then informs the analysis and control means of the value of the instantaneous angle of incidence to allow these means to control the corresponding motor.

 This sensor then returns the corresponding information to the analysis and control means.

 The angular position sensor can also be in the form of a potentiometer or the like and can be integrated into a bearing for example of guiding in rotation of the squeegee support arm or into the drive motor of the mechanism.

 This sensor informs the analysis and control means of the instantaneous position of the squeegee to allow the control of the pressing force, the angle of incidence, etc., in particular around the fixed and opposite stop positions. fixed stop of the scanning cycle.

 This allows the analysis and control means to calculate by derivation, the scanning speed and acceleration.

 The intensity sensor of the drive motor can be integrated directly into the power supply of this motor.

 This sensor delivers to the analysis and control means, current consumption information of the corresponding motor.

 This information, combined with the resistance torque information, makes it possible to determine the presence of an obstacle on the window and the coefficient of friction of the squeegee thereon.

 The variation in the intensity of the supply current to the drive motor makes it possible to control the variation in the scanning speed of the mechanism.

 The vehicle speed sensor can for example be an opto-electronic sensor or the like and be the same as that already used by other systems on board the vehicle, such as for example the anti-lock wheel system.

 This sensor delivers the instantaneous speed of the vehicle to the analysis and control means.

 This information makes it possible to act on the pressing force of the squeegee and can also act on the scanning speed.

 The rain sensor is for example an optical, diode, piezoelectric or other sensor. This sensor makes it possible to detect the presence of water on the window to inform the analysis and control means so as to automatically activate the wiper mechanism and to regulate the wiping speed as a function of the amount of water on this window.

 The activation means which can be actuated by the user have a conventional structure well known in the art and can for example be in the form of a rotary selector, slider or other member.

 These means make it possible to control the different possible operating modes of the wiper mechanism, namely, stopping, automatic, high speed, low speed or other.

 These activation means optionally control the wiping mechanism of the windshield and the wiping mechanism of the rear window of the vehicle.

 Finally, the aerodynamic pressure sensor can have any suitable structure, making it possible to calculate the actual speed at the level of the window.

 A pre-established map of the field of aerodynamic forces on the glass as a function of the actual speed and the sweep angle makes it possible to apply the necessary downforce for each sweep position.

 There is shown in Figure 5, a curve illustrating an example of evolution of the angle of incidence a of a squeegee relative to a window during a scanning cycle. This angle of incidence changes as a function of the geometry of the glass and of the orientation given to the squeegee support arm.

 However, it can be seen that the shape of the ideal curve of this angle between the fixed stop and opposite fixed stop positions is a function, for example, of the curve of the window.

 The ideal would be to have between the extreme positions of the scanning cycle always the same value of the angle of incidence of the squeegee relative to the window and this independently of the scanning direction.

 To keep this angle, it is necessary that the squeegee makes at each angular position of the cycle, the same angle with the normal to the window during a demicycle, this angle can be different between two consecutive demicycles.

 In Figure 6, there is shown a curve illustrating the pressing force F during a scanning cycle.

 It is known in fact that in order to have a good reversal of the squeegee blade at each end of the scanning half-cycle, that is to say around the fixed stop and opposite fixed stop positions of the cycle or at least to facilitate it, the contact force must be reduced at the time of turning.

 However, this bearing force must not go below a limit threshold S because the squeegee would then no longer fulfill its main wiping function.

This support force is not always the same and can change according to several parameters.

 Indeed, the pressing force increases or decreases depending on the speed, the external shape of the vehicle, etc.

 It is known that at certain speeds, the aerodynamic forces tend to press the squeegee in particular on the vehicle windshield, while at other speeds, it is the reverse.

 In addition, these aerodynamic forces can, at low speed, cause the squeegee to take off, then at a little higher speed, tackle it and at high speed make it take off again. This is a function of the exterior shape of the vehicle, the thresholds for passing from one state to another being different from one vehicle to another.

 In addition, the wind can also participate with the aerodynamic effect to disturb this support force.

 The wear of the squeegees also has an influence on this.

 This force can also vary depending on the angular position of the arm insofar as the air flow for example on the windshield of a vehicle is not uniform in speed and direction.

This bearing force is effectively not the same if the squeegee is normal to the windshield (zero angle of incidence) or if it makes another angle of incidence with it.

 Finally, the configuration of the window and the sweep angle also have repercussions on this force because the force generated on the squeegee support arm changes during a sweep cycle, insofar as the height between the attachment points of the squeegee and the attachment point of the support arm of the latter, evolves according to the curve of the windshield.

 In FIG. 6, it can therefore be seen that in order to obtain a good turning or at least to facilitate it, it is advisable to reduce the bearing force of the squeegee on the glass at the time of its turning, that is to say around the fixed and opposite stop positions fixed stop of the cycle, without going below a minimum threshold of pressing force.

 It is also possible to determine a good turning or a bad turning of the squeegee blade at each end of the half cycle.

 This characteristic R can be identified by a digital processing, for example of the signal of the engine torque or the coefficient of friction or by a crude analysis of the coefficient of friction and the signal of the engine torque, these being saturated at the time of the reversal and decreasing then.

The digital processing can for example be carried out by a conventional signal processing by FFT or
DSP of the signal returned by the sensor correspond around the fixed stop and opposite fixed stop positions of the cycle, the result of this processing making it possible to qualify the state of the reversal, that is to say good or bad, as illustrated in Figures 7 and 8 respectively.

 It will therefore be understood that in the control system according to the invention, different information is taken into account making it possible to analyze the operating conditions of the wiper mechanism, in order to control different parameters for controlling the means involved in the constitution of this one, to optimize the functioning of this mechanism.

 It goes without saying of course that different embodiments of the system which has just been described can be envisaged.

Claims (6)

 1. System for controlling the operation of a wiper mechanism of a motor vehicle, characterized in that it comprises  - means (1) for driving at least one arm (2) for supporting at least one wiper (3),  - means (4) for adjusting the pressing force of said squeegee on the window,  - means (5) for controlling the inclination of said squeegee relative to the window,  - Means (14) for reading the operating conditions of the wiper mechanism, and  - Means (15) for analyzing these operating conditions to determine optimal control parameters for the different means of the wiper mechanism and for piloting these different means from these control parameters to optimize the operation of this one.  2. System according to claim 1, characterized in that the means for reading the operating conditions of the wiper mechanism, comprise a sensor (16) of vehicle speed, a sensor (17) of aerodynamic pressure, a sensor (18) of rain, a sensor (19) of the torque resistant to the mechanism, a sensor (20) of the angular position of the mechanism, a sensor (21) of intensity consumed by the drive means, a sensor (22) of bearing force of the squeegee on the glass, a sensor (23) of angle of incidence of the squeegee relative to the glass, and a state sensor (24) of activation means that can be manipulated by a user.  3. System according to claim 1 or 2, characterized in that the drive means (1), the adjustment means (4) of the pressing force and the control means (5) of the inclination, of the window wiper mechanism, include electric motors (10,11,12,13).  4. System according to any one of the preceding claims, characterized in that the analysis and control means (15) comprise an information processing unit (28) receiving as input the information relating to the operating conditions of the wiper mechanism and associated with means for storing information for optimal control of the wiper mechanism as a function thereof.  5. System according to claim 4, characterized in that the optimal control information is in the form of predetermined information tables of operation of the wiper mechanism.  6. System according to claim 4, characterized in that the optimal control information is in the form of means for modeling the operation of the wiper mechanism making it possible to calculate the optimal control parameters from the operating conditions of this one.