FR2941792A1 - METHOD FOR CONTROLLING AN OPENING OF A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a control method of an opening implemented by an electric motor (11), and involving a sensor adapted to emit pulses under the effect of the rotation of said motor (11), said pulses being representative of the rotational speed of said motor (11), consisting in repeating the following sequence: estimating a time interval (Δt) between two pulses of rank n + 1 and n, from a previous time interval (Δt), measured between the two pulses of rank n-1 and n; measuring this time interval (Δt) between the two pulses of rank n + 1 and n; comparing the estimated time interval (Δt) with the measured time interval (Δt); trigger an alarm, which stops the opening of the opening, if the measured time interval (Δt) is greater than the estimated time interval (Δt). The invention finds immediate application in the field of motor vehicles.

Description

METHOD FOR CONTROLLING AN OPENING OF A MOTOR VEHICLE

The present invention relates to a method of controlling a motor vehicle door. The invention more particularly proposes a method of controlling an opening such as a sliding side door, a hatch or trunk, a retractable roof or even electric windows with sequential opening for example, comprising an anti-pinch function. The performance of such a system is often judged by the uniformity of the movement of the opening concerned, that is to say by its speed, its fluidity, as well as by the stability of the movement over time and what whatever the life situation of the vehicle. In the design of current vehicles, the development of these motorized openings provides a major advantage in assisting or substituting passengers for maneuvers related to the opening and / or closing of the doors. These motorized openings thus make it possible to increase the comfort of the passengers notably thanks to their great simplicity of use. On the other hand, the opening and the automatic closing of a motorized opening necessarily involves securing as much as possible the opening and / or closing movements of the opening so as to avoid injuring a passenger or damaging the passenger. vehicle. In order to remedy this problem, it has been developed a function called anti-pinch function implemented by a control method of the opening to detect an obstacle when opening or when closing the door and so stop movement if an obstacle is present. Obstacle means, in particular an object present in the motor vehicle, an object outside the motor vehicle such as a sidewalk or a person. For this purpose, different standards exist so that the doors do not generate greater effort than the maximums required vis-à-vis standardized obstacles.

However, external disturbances corresponding to different situations of life of the motor vehicle cause variations with respect to the normal conditions of use of the sash and sometimes make it difficult to detect an obstacle.

These external disturbances are mainly due to the diversity of the vehicle environment: sloping or sloping road, the diversity of the climatic environment: variation of temperature and hygrometry, as well as the disparity in the environment. manufacture of the various elements of the opening / closing mechanism of the opening. Among these different situations of vehicle life, two extreme cases can then cause either a non-detection of an obstacle, resulting in an inefficient anti-pinch function; a detection of a ghost obstacle preventing the normal opening / closing operation of the motorized opening.

In this context, the invention aims to provide a method of controlling an opening of a motor vehicle to overcome these disadvantages and allowing operation of the anti-pinch function regardless of external disturbances and adapting to various life situations of the vehicle. To this end, the invention proposes a method for controlling an opening of a motor vehicle implemented by an electric motor, and involving a sensor adapted to transmit pulses under the effect of the rotation of said motor, said pulses being representative. the rotational speed of said engine, characterized in that it consists in repeating the following sequence, from the beginning of the opening of the opening: - estimate a time interval between two successive pulses of rank n + 1 and n, from a previous time interval, measured between the two successive pulses of rank n-1 and n; measuring this time interval between the two successive pulses of rank n + 1 and n; - compare the estimated time interval with the measured time interval; - trigger an alarm, which stops the opening of the opening, if the measured time interval is greater than the estimated time interval. According to a particular embodiment, the control method is such that the step of triggering an alarm that stops the opening of the door comprises an operation of interrupting said rotation of said motor or performing a procedure for disengaging said opening moving said opening in opposite direction on a predetermined stroke. According to a particular mode of implementation, the control method is such that said method comprises a step of storing the instants of pulse transmissions of said pulse sensor.

According to a particular mode of implementation, the control method is such that said time interval (Atn + 1), between two successive pulses of rank n + 1 and n, is estimated by the relation: Otn + l = Atn + S; where: S is a safety margin; Atn is said previous time interval measured between the two successive pulses of rank n-1 and n. According to a particular embodiment, the control method is such that said time interval (Atn + i), between two successive pulses of rank n + 1 and n, is estimated by the relation: Otn + l = 2 * Otn -Otn_1 + S; where: S is a safety margin; Atn is said previous time interval measured between the two successive pulses of rank n-1 and n; Atn_1 is a time interval measured between the two successive pulses of rank n-2 and n-1.

According to a particular embodiment, the control method is such that said time interval (Atn + 1), between two successive pulses of rank n + 1 and n, is estimated by the relation Otn + 1 = Atn + ( Atn ù Atnù1 + S) * C (EA); where: S is a safety margin; Atn is said previous time interval measured between the two successive pulses of rank n-1 and n; Atn_1 is a time interval measured between the two successive pulses of rank n-2 and n-1; C is a confidence coefficient; eo is a difference between said previous time interval (Atn) measured between the two successive n-1 and n-period pulses and a reference time interval. The present invention also relates to a control computer comprising means for implementing a driving method of a motor vehicle opening according to the invention. According to another characteristic, said means comprise. means for determining time intervals between each pulse; means for estimating a theoretical time interval; means for measuring the time flowing from one pulse to a next pulse, the measured time constituting a real time interval; means for comparing said theoretical time interval with said real time interval. Other characteristics and advantages of the invention will emerge more clearly from the description which is given below, by way of indication and in no way limitative, with reference to the appended figures, among which: FIG. 1 is a schematic representation illustrating the operating principle of a motorized opening controlled by a control method according to the invention; FIG. 2 illustrates the detection principle implemented by the control method of an opening of a motor vehicle according to the invention; FIG. 3 is a block diagram of a first embodiment of the means for detecting an obstacle of a motorized piloting device implemented by the method according to the invention; FIG. 4 particularly illustrates a step of counting the method according to the invention implemented by the detection means illustrated in FIG. 3; - Figure 5 illustrates a block diagram of a second embodiment of the means for detecting an obstacle of a motorized driving device implemented by the method according to the invention; FIG. 6 illustrates the variation of a confidence coefficient C. FIG. 1 is a schematic representation illustrating the operating principle of a motorized opening controlled by the control method according to the invention. The device 100 for opening / closing a motorized opening shown in FIG. 1 is of the electric window lifter type and comprises an opening 10, an electric motor 11 comprising a shaft. The shaft is integral with a reduction stage 13 adapted to reduce the speed of rotation of the motor shaft 11, the geared motor being secured to a drum 14. The drum 14 is a circular piece concentric with the reduction stage 13 and has on its peripheral portion a flare adapted to receive and drive a cable 15 or a belt.

The cable 15 is secured to a support 16, supporting the opening 10, so that a rotation of the drum 14 causes a translation of the support 16 along a guide 19 thus creating the motorized movement of the opening 10. The opening / closing device 100 of a motorized opening also comprises a control computer 17 of the opening 10 comprising means 18 for the detection of an obstacle allowing at least to stop the motorized movement of the opening 10 when an obstacle is detected by the means 18 for the detection of an obstacle. Obstacle means, in particular an object present in the motor vehicle, an object outside the motor vehicle such as a sidewalk, or a person who may possibly be on the path of movement of the opening. The means 18 for the detection of an obstacle use, in particular as input data, a signal supplied by a fixed pulse sensor of the hall effect sensor type; the hall sensor is often used to measure the rotational speed of the shaft of an electric motor 11. The pulse sensor is disposed parallel to the axis of rotation of the shaft of the electric motor 11, on which is integrally mounted a magnet of cylindrical shape whose magnetization is formed by alternating North and South poles poles. Pulse sensors are those sensors delivering a pulse for all values a, where 0 <a <-1 and a = 1 / N motor revolution, where N is a natural integer. The rotation of the shaft of the electric motor 11 causes the successive passage of a north pole and a south pole of the magnet in front of the pulse sensor causing the generation of pulses by the sensor every 1 / N turns of the electric motor 11.

Thus, the means 18 for detecting an obstacle are capable of detecting a deceleration of the shaft of the electric motor 11 by monitoring a variation of the time interval between two successive pulses emitted by the pulse sensor. For this purpose, the means 18 for the detection of an obstacle estimate, at each pulse emitted by the pulse sensor, the instant of emission of the next pulse as a function of the time interval elapsed between two previous pulses. Note also that the time interval between two pulses is representative of the speed of the shaft of the electric motor 11 between these two same pulses.

The estimated duration of the time interval between two pulses will be named in the following description Atn, where n is a natural integer, and will correspond to a displacement of the opening 10 without load torque created by the presence of a obstacle.

The actual duration of the time interval between two pulses delivered by the sensor will be named in the following description Atn, n being an integer, and will correspond to the actual behavior of the opening 10. Thus, if the means 18 for the detection of an obstacle measure a real duration of the time interval Δt, greater than the duration of the estimated time interval Atn, then the opening 10 is slowed during its displacement during the opening phase or closing, meaning that an obstacle is present in the path of the kinematics of the opening 10. The means 18 for the detection of an obstacle will then trigger an alarm which, for example, will stop the movement of the opening. The means 18 for the detection of an obstacle 35 must then estimate as accurately as possible the time interval At, separating two successive pulses and whatever the life situation of the vehicle. For this purpose, Figure 2 illustrates particularly in the form of a graph, the detection principle implemented by the method of controlling a motor vehicle opening according to the invention. FIG. 2 more particularly illustrates pulse generation times generated by the pulse sensor, as well as the estimation of the moment of delivery of the following pulses. In the remainder of the description, the following will be named: the moments of generation of the pulses by the pulse sensor and the estimated instants of pulse generation by the sensor. It should be noted that the pulses emitted by the pulse sensor are pulses sampled according to a sampling period t o such that the instant of delivery of the real pulse is echoed over the next sampling period; the sampling thus making it possible to obtain a time interval between two pulses delivered by the sensor equivalent to Ot = a * te where a is a constant integer. Thus, the graph, represented in FIG. 2, thus illustrates from top to bottom: the instants of delivery of the pulses generated by the pulse sensor; the estimated instants of delivery of the pulses determined by the means 18 for detecting an obstacle; The time intervals separating the actual pulses from the estimated pulses. The means 18 for the detection of an obstacle estimate the instant of generation of the pulse, emitted by the pulse sensor, at the instant of delivery of the pulse tn_1. The time interval Δt, defined by tnùtn_1 then corresponds to the estimate of the relative interval between two successive pulses. According to the illustration of FIG. 2, the first three pulses delivered by the pulse sensor at times tn_2, tn_1 and tn, precede the delivery estimates of the pulses generated by the means 18 for the detection of an obstacle. These first three pulses represent situations in which no event disturbs or delays the instant of delivery of the pulses by the sensor, in other words, no obstacle has slowed down or disturbed the rotational speed of the shaft of the electric motor. On the other hand, the last pulse delivered by the sensor at time t2, shown in dashed lines, is generated after the delivery estimate of the pulse tn + 1. The shaft of the electric motor 11 has therefore undergone a slowdown in its rotational speed due for example to a load torque created by the presence of an obstacle. The means 18 for the detection of an obstacle then determine the presence of an obstacle by detecting a delay in the transmission of the pulse by the sensor and activate an alarm that will stop the movement of the opening 10. FIG. 3 is a schematic representation of the operating principle of the means 18 for detecting an obstacle of a motorized driving device 100. By way of reminder, pulses emitted pulses are open pulses according to the invention. Following the description, it will be considered that sampled according to a sampling period te so that the moment of delivery of the real pulse is echoed over the next sampling period, thus making it possible to obtain a time interval between two pulses. delivered by the sensor equivalent to Ot = a * te where a is a constant integer.

The means 18 for the detection of an obstacle comprise an estimator 31 activated on the rising edge of the pulses delivered by the pulse sensor and comprise a certain number of complementary inputs capable of supplying information according to the defined estimation principle; the different estimates will be detailed in the following description. In order to predict as finely as possible the instant of delivery of the next pulse, the estimator 31 delivers its estimate at the times when it is activated, that is to say that it estimates the instant of delivery of the impulse tn + i at t ,. In this first embodiment, the estimator 31 is based on the following principle: Otn + l = Otn.

During an opening or closing movement of the sash, if the speed of the shaft of the electric motor 11 is constant during three successive pulses, then the estimator 31 estimates the time interval between two successive pulses. according to the following law: Otn + l = Atn + S; where S is a safety margin. This safety margin S is determined by the means 18 for detecting an obstacle as a function of the validity of the time interval Atn and as a function of the maximum possible variations admitted between two successive pulses, without load torque due to the presence of an obstacle. The safety margin S also takes into account the small variations in time intervals between the actual pulses emitted by the sensor and the pulses sampled according to a sampling period, the rotational speed of the motor shaft 11 does not vary. being not perfectly constant. During an opening or closing maneuver during which the speed of the shaft of the electric motor 11 is constant during two successive pulses, then the estimator 31 estimates the time interval Atn + 1 between two successive pulses according to the following law: Otn + 1 = 2 * Atn ù Atnù1 + S, where S is the margin of safety set according to the validity of the assumption of the estimate, that the speed of the motor shaft is assumed to be constant between two successive impulses. Indeed, if the rotation speed of the motor shaft 11 is not strictly constant between two successive pulses, then these variations must be included in the safety margin S; the safety margin S also includes other predictable variations. Thus in this first embodiment, the estimator 31 admits as complementary input the time interval Atn between the current pulse and the previous pulse delivered by the sensor. At each sampling instant, a counter 32 receives as input information: the pulse delivered by the pulse sensor and the estimated time interval Atn before the next pulse delivered by the estimator 31. The counter 32 is initialized at each pulse generated by a value corresponding to the estimated time interval before the next pulse.

The counter 32 counts from the time of initialization the time remaining before the next estimated pulse. The count of the counter 32 is performed by means of a signal decreasing linearly in time, and resetting at each pulse generated by the pulse sensor. Thus, the signal of the counter 32 is reset at each pulse by a value proportional to the estimated time interval Atn. In order to have a unit decrement at each sampling instant, the counter 32 is At n + 1 at the instant tn at the value n + 1 being the sample period. FIG. 4 particularly illustrates the decrementing of the signal of counter 32 at four pulsing emission times tn_2, tn_1, tn and tn + 1.

During the generation of the pulse by the sensor at time tn the time necessary for a decrementation of the signal of the counter 32 up to a threshold value, such as for example 0, corresponds precisely to the time interval

10 estimated Atn + 1 which is delivered by the estimator 31 during the impulse tn.

Finally, decision means 33 activate an alarm if the pulse generated by the sensor, for example at tn + r, occurs when the counter signal 32 has

15 reaches or exceeds the threshold value; that is to say when the pulse generated by the sensor occurs after estimating the pulse tn + 1. Thus the alarm is activated if Atn + l> Otn + l This first embodiment is based on a

The hypothesis of having a constant speed of the motor shaft between two or three successive pulses; however this first embodiment is also applicable when measuring a substantially constant acceleration between two or three

25 successive pulses. The method implemented by the means 18 for detecting an obstacle, according to this first embodiment, comprises:

a step of acquisition of the pulses emitted by the pulse sensor; a step of measuring a time interval Atn between a first pulse and a second pulse; a step of estimating a time interval

Atn + 1 between the second pulse and a third pulse to come; a step of counting the time flowing since the transmission of the second pulse; a step of comparing the estimated time interval Atn + 1 between the second pulse and the third pulse with the real time interval Atn + 1 between the second pulse and the third pulse; an activation step of an alarm if Atn + 1> Atn + 1 FIG. 5 illustrates a second embodiment of the means 28 for the detection of an obstacle of a motorized driving device of an opening according to FIG. 'invention. In this second embodiment, the estimated time interval Atn + 1 determined by the estimator 41 is adjustable by means of a confidence coefficient C and the means 28 for the detection of an obstacle comprise means 27 for recording a reference time interval. The reference time interval corresponds to a time interval between two successive pulses measured during a previous operation of the sash performed without obstacle. This previous maneuver is preferably a closing maneuver performed between a first position and a second position, the first and the second position being advantageously stop positions of the opening. In this second embodiment of the invention, the estimator 41 admits as complementary inputs: the time interval Atn between the current pulse and the preceding pulse as well as the coefficient of confidence C varying according to the difference between this measured time interval Atn and the reference time interval. Thus, this second embodiment of the invention consists in comparing, at each pulse of the sensor, a reference time interval with a measured time interval Atn between two successive pulses and whose detection accuracy is variable as a function of the difference measured between these two intervals. For this, the time interval Atn + 1 is determined, in this second embodiment, by the following equation: Otn + 1 = Atn + (Atn ù Atn1 + S) * C (EA), where: C is the confidence coefficient; E. is the difference between the measured time interval Atn between two successive pulses and the reference time interval; S is the margin of safety. In a manner similar to the description of the first embodiment of the invention, the safety margin S involved in the determination of the time interval Atn + 1 is determined by the means 28 for detecting an obstacle in according to the validity of the time interval Atn and as a function of the maximum possible variations between two successive pulses, without load torque due to the presence of an obstacle. The confidence coefficient C is a variable dependent on the difference eo and whose variation profile as a function of the difference eo is represented by a graph illustrated with reference to FIG. 6. If the difference eo between the interval measured time and the reference time interval is small, then the confidence coefficient C will be close to 1. On the other hand, if the difference eo between the measured time interval and the reference time interval is very small. importantly, the confidence coefficient C will be less than or equal to 0 in order to improve the sensitivity for the detection of an obstacle. Thus, this second embodiment makes it possible to more precisely determine the time interval Atn + 1 and to detect an obstacle more rapidly. The variation of the confidence coefficient C between its maximum value, close to 1, and its minimum value, close to 0, is delimited by a first threshold T1 and by a second threshold T2, the two thresholds T1 and T2 being determined and calibrated. depending on the application. Thus, this second embodiment of the invention makes it possible to detect suitably and whatever the life situations of the vehicle, for example slow aging of the process, the presence of an obstacle on the opening or closing path of the vehicle. 'a precisely opening. Indeed, the confidence coefficient C makes it possible to adjust the accuracy of the detection of the obstacle by allowing, for example, to avoid the detection of a ghost obstacle when the vehicle has evolved slowly. The reference time interval is determined by software means by means of a polynomial representing the variations of the intervals At, as a function of the position of the opening 10 by the least squares method whose equation is (XX) - 'X'Y, where the coefficients a are estimated from the time intervals At, (Y) of an inverse matrix X representing the positions of the opening during the measurement of the time intervals At, . The matrix X is a matrix of the type X = [1 x x 2 x n ~, where the vector x represents the different positions of the opening 10 corresponding to the 25 measurements of the time intervals Δt. Thus, the method of controlling an opening of a motor vehicle according to the invention makes it possible to optimally detect the presence of an obstacle regardless of the life situation in which the motor vehicle is located while avoiding the detection of a ghost obstacle or the non-detection of an obstacle. Indeed, the method of controlling an opening of a motor vehicle is implemented by means of a device comprising means for the detection of an obstacle making it possible to modify the detection sensitivity of an obstacle as a function of the vehicle life situation, which ensures an effective anti-pinch function. The control method is advantageously triggered from the beginning of the race of the opening; however, it is also possible to trigger the piloting process beyond a certain stroke of the opening determined by estimating that before reaching this race a child has enough time to withdraw his hand or his arms.

Other advantages of the invention include the following. - reduction of the effort required to detect obstacles; - detection method requiring few calculations.

Claims (8)

REVENDICATIONS1. A method of controlling an opening of a motor vehicle implemented by an electric motor (11), and involving a sensor adapted to transmit pulses under the effect of the rotation of said motor (11), said pulses being representative of the speed rotation of said motor (11), characterized in that it consists in repeating the following sequence, from the beginning of the opening of the opening: - estimate a time interval (Otn + 1) between two successive pulses of rank n +1 and n, from a previous time interval (Atn), measured between the two successive pulses of rank n-1 and n; - measuring this time interval (Otn + 1) between the two successive pulses of rank n + 1 and n - comparing the estimated time interval (Otn + 1) to the measured time interval (Otn + 1); - trigger an alarm, which stops the opening of the opening, if the measured time interval (Otn + 1) is greater than the estimated time interval (Otn + 1). 2. A method of driving a motor vehicle door according to claim 1 characterized in that the step of triggering an alarm that stops the opening of the door comprises an operation of interrupting said rotation of said motor (11) or performing a release procedure of said opening 30 moving said opening in opposite direction on a predetermined stroke. 3. A method of driving a motor vehicle door according to one of claims 1 to 2 characterized in that said method comprisesa stepconsistent to store the pulse emission times of said pulse sensor. 4. A driving method of a motor vehicle opening according to one of claims 1 to 3 characterized in that said time interval (Atn + 1), between two successive pulses of rank n + 1 and n, is estimated by the relation Atn + 1 Atn + S; or . S is a safety margin Atn is said previous time interval measured between the two successive pulses of rank n-1 and n. 5. A driving method of a motor vehicle door according to one of claims 1 to 3 characterized in that said time interval (Atn + 1), between two successive pulses of rank n + 1 and n, is estimated by the relation Atn + 1 2 * Atn ù Atnù1 + S; where: S is a safety margin Atn is said previous time interval measured between the two successive pulses of rank n-1 and n; Atn_1 is a time interval measured between the two successive pulses of rank n-2 and n-1. 6. A method of driving a motor vehicle door according to one of claims 1 to 3 characterized in that said time interval (Otn + 1), between two successive pulses of rank n + 1 and n, is estimated by the relation Otn + 1 = Atn + (Atn û Atnù1 + S) * C (EA); where: S is a safety margin Atn is said previous time interval measured between the two successive pulses of rank n-1 and n; Atn_1 is a time interval measured between the two successive pulses of rank n-2 and n-1; 19 C is a confidence coefficient; SA is a difference between said previous time interval (Atn) measured between the two successive pulses of rank n-1 and n and a reference time interval. 7. Control computer (17) characterized in that it comprises means (18) for implementing a driving method of a motor vehicle opening according to one of claims 1 to 6. 10 8. Control computer (17) according to claim 7 characterized in that said means (18) comprise. means for determining time intervals (Atn) between two successive pulses of rank n-1 and n; means for estimating a time interval (Atn + 1) between two successive pulses of rank n + 1 and n; Means for measuring the time flowing from a pulse of rank n to a next pulse of rank n + 1, the measured time constituting a time interval (Atn + 1); means for comparing said estimated time interval (Atn + 1) with said measured time interval (Atn + 1).