Capacitive presence sensor for motorized flush door handle

Abstract

A capacitive presence sensor (40) intended to be integrated into a motorized flush door handle (10) of a motor vehicle, and comprising: - at least one measuring electrode (41), integrated on a printed circuit board (42) and intended to form a measuring capacitor with a part of the body of a human operator; - a detection circuit (43) connected to at least one measuring electrode (41); - a microcontroller (44); and - an accelerometer (45) integrated on the printed circuit board (42) and connected to the microcontroller (44), the microcontroller (44) being configured to determine information (401) relating to a presence detection by using in particular an acceleration signal provided by the accelerometer (45).The invention thus proposes a presence sensor that directly provides a signal corrected for the effect of movements of the motorized flush door handle, thereby improving compatibility with any type of central computer dedicated to processing the data provided by the presence sensor (40). Figure for the abstract: Figure 2.

Description

Title of the invention: Capacitive presence sensor for motorized flush door handle technical field

[0001] The invention relates to the field of capacitive type presence sensors in a motor vehicle. State of the art

[0002] In a motor vehicle, it is known to use capacitive sensors to detect a human presence and trigger vehicle functions. For example, it is known to mount a capacitive sensor in the door handles to detect the presence of a vehicle user's hand and thus unlock the doors.

[0003] Such detection is possible because the proximity of a part of the human body increases the electrostatic field. This electrostatic field causes the capacitance value of a measuring capacitor formed by a measuring electrode to vary. Thus, a sudden change in said capacitance value indicates a change in the immediate environment of the measuring electrode: either the arrival or departure of a part of the human body in the immediate vicinity of the measuring electrode.

[0004] Nowadays, motorized flush door handles are becoming increasingly popular in the automotive field.

[0005] A motorized flush door handle, or "flush" handle, is a door handle capable of assuming, in use, at least two positions from among: - a resting position, in which it is flush with the outer surface of the door, and - a gripping position, in which at least part of the handle is arranged offset relative to the external surface of the door, thus providing a grip for the user.

[0006] Such a handle is moved from one position to another by means of a motor unit comprising an electric motor and its control system. This is therefore referred to as a motorized flush handle.

[0007] By "flush with the external surface of the door", it is meant that a surface topology, at the interface between the handle and the external surface of the door, has a jump in value of zero or negligible, for example of value less than 3 mm (without considering the gap between the handle and the external surface of the door).

[0008] Throughout the text, and for reasons of brevity, the term "handle" or "door handle" may be used to refer to the flush door handle. motorized.

[0009] In the gripping position, at least a portion of the handle is offset relative to the outer surface of the door. This offset may be outward from the vehicle. The gripping position then corresponds to a deployed position of the handle, in which at least a portion of the handle protrudes relative to the outer surface of the door, in the direction of the vehicle's exterior. Alternatively, it may be offset inward from the vehicle, with a portion of the handle moving inward to provide access to a recess into which the user's hand is inserted to operate the handle.

[0010] The transition from one position to another is advantageously controlled by a central computer, in response to a predetermined detection. This is, for example, the detection of the entry of an authorized user into a predetermined perimeter, via bidirectional communication between a communication module of the vehicle and an electronic key implemented in a dedicated badge (keyfob) or even in a smartphone.

[0011] Advantageously, once the door handle has been moved into the deployed position, a presence sensor mounted in the handle detects the presence of the user's hand, so as to unlock the doors when the hand is in the immediate vicinity of said handle.

[0012] When a capacitive presence sensor is mounted in the flush door handle, the measuring electrode will move relative to the rest of the door when the handle is extended or retracted. More specifically, the measuring electrode will move relative to a large metal part formed by the door panel, which will affect the capacitance value of the measuring capacitor. This can generate false detections by the presence sensor, for example, by mistaking the presence of the user's hand in the immediate vicinity of the sensor for a simple extension or retraction of the flush door handle.

[0013] Prior art solutions based on post-detection signal processing are known. In particular, a central computer is connected both to a capacitive presence sensor and to a mechanical switch that takes an open or closed position depending on whether the handle is in the folded or extended position. The capacitive presence sensor provides the central computer with a raw signal representing the time evolution of the electrical capacitance of the measuring capacitor. The central computer is then configured to correct the raw signal using data provided by the mechanical switch, so as to ignore a presence detection occurring simultaneously with a change in the position of the mechanical switch.

[0014] The invention aims to improve this prior art, by proposing a robust and simple solution to overcome detection errors when a capacitive type presence sensor is mounted in a motorized flush door handle. Description of the invention

[0015] This objective is achieved with a capacitive presence sensor, intended to be integrated into a motorized flush door handle of a motor vehicle, and comprising: - at least one measuring electrode, integrated on a printed circuit board and intended to form a measuring capacitor with a part of the body of a human operator; - a detection circuit comprising capacitors and switches, integrated on the same printed circuit board and connected to at least one measuring electrode; and - a microcontroller, configured to control the detection circuit, to perform voltage and / or current measurements on said detection circuit, and to determine, from said measurements, information relating to a presence detection.

[0016] According to the invention, the presence sensor further comprises an accelerometer connected to the microcontroller, said accelerometer is integrated on the printed circuit board, and the microcontroller is configured to determine the information relating to a presence detection by further using an acceleration signal provided by the accelerometer.

[0017] The accelerometer and the measuring electrode are integrated on the same printed circuit board. They are thus mounted together. In operation, the accelerometer therefore measures accelerations of the measuring electrode relative to the rest of the vehicle, in particular the metal door panel.

[0018] The acceleration signal provided by the accelerometer and relating to the movement of the measuring electrode is supplied directly to the microcontroller of the presence sensor. The latter is thus able to directly integrate this data into a presence detection signal.

[0019] The invention thus offers a completely autonomous solution, eliminating detection errors when a capacitive presence sensor is mounted in a motorized flush door handle. In particular, it is no longer necessary to provide independent sensors such as mechanical switches. Most importantly, it is no longer necessary to adapt the central control unit to receive information from these mechanical switches and to correct a raw signal so as to ignore a presence detection occurring simultaneously with a change in the position of the mechanical switch. This correction is performed by the microcontroller directly at the presence sensor.

[0020] The invention thus proposes a presence sensor directly providing a signal corrected for the effect of movements of the motorized flush door handle, which improves compatibility with any type of central computer dedicated to the exploitation of the data provided by the presence sensor.

[0021] Preferably, the microcontroller is configured to implement the following steps: - construction of an initial signal representative of an evolution, as a function of time, of the electrical capacitance of the measuring capacitor; - construction of a corrected signal, by removing from the initial signal variations in electrical capacitance that coincide with a peak in the acceleration signal; and - determination of information relating to a presence detection, from said corrected signal.

[0022] Advantageously, the accelerometer is sensitive to accelerations along at least one axis, in particular an axis called the axis of interest, the axis of interest being inclined at most 30° relative to an axis of translation of the measuring electrode, in use in a motorized flush door handle during tilting between a rest position and a gripping position.

[0023] Advantageously, said axis of interest is inclined at most 30° relative to the normal to the plane of the printed circuit board.

[0024] Preferably, the presence sensor according to the invention is configured to send the information relating to a presence detection to a central computer capable of controlling a locking and / or unlocking of at least one opening of the motor vehicle.

[0025] The invention also covers a motor vehicle door equipped with a motorized flush door handle and a main body panel, and in which: - the motorized flush door handle is capable of moving between a rest position and a gripping position; - the motorized flush door handle receives a presence sensor according to the invention, movable relative to the main panel during a change between the rest position and the gripping position of the motorized flush door handle.

[0026] The invention finally covers a method implemented in the microcontroller of a presence sensor according to the invention, comprising the following steps: - construction of an initial signal representative of an evolution, as a function of time, of the electrical capacitance of the measuring capacitor; - construction of a corrected signal, by removing from the initial signal variations in electrical capacitance that coincide with a peak in the acceleration signal; and - determination of information relating to a presence detection, from the signal corrected. Description of the figures

[0027] Other features and advantages of the invention will become apparent from the following description. This description is purely illustrative and should be read in conjunction with the accompanying drawings, in which:

[0028] [Fig.1A] [Fig.1A] schematically illustrates a motorized flush door handle in a retracted position;

[0029] [Fig.1B] Fig.1B schematically illustrates a motorized flush door handle in a deployed position;

[0030] [Fig.2] Fig.2 schematically illustrates a presence sensor according to the invention; and

[0031] [Fig.3] Fig.3 schematically illustrates different signals generated in a presence sensor according to the invention.

[0032] Detailed description of at least one embodiment

[0033] To facilitate understanding, the axes of an orthonormal coordinate system (xyz) have been represented on at least some of the figures.

[0034] First, with reference to figures IA and IB, a flush door handle 10 is described. In use, the handle 10 forms the handle of a door of a motor vehicle, not shown.

[0035] The motorized flush door handle 10, or "Bush" handle, is capable of assuming, in use, at least two positions from among: - a resting position, in which it is flush with the external surface 21 of the door 20, and - a gripping position, in which at least part of the handle is arranged offset relative to the external surface 21 of the door 20, thus providing a grip for the user.

[0036] In the example illustrated in Figures IA and IB, the handle 10 extends outwards from the vehicle

[0037] In [Fig. 1 A], the handle 10 is shown in the rest position. It is housed inside a recess 11 formed in the door 20, and is flush with the external surface 21 of the door.

[0038] The external surface 21 of the door belongs to a door panel, made of metal.

[0039] In [Fig. IB], the handle 10 is shown in the gripping position, with a gripping portion 12 located outside the housing 11, and a deployment portion 13 taking a deployed position and extending between the door 20 and said gripping portion 12.

[0040] The handle 10 is connected to a motor unit 30 which includes a motor electric and its control system. The motor unit 30 is configured to move the handle 10 from the rest position to the gripping position. Advantageously, the control system of the motor unit 30 is configured to control a tilting of the handle 10 from its rest position to its gripping position, in response to a predetermined detection. This is, for example, the detection of an authorized user entering a predetermined perimeter, via two-way communication between a communication module in the vehicle and an electronic key implemented in a dedicated badge or even in a smartphone carried by said user.

[0041] The handle 10 incorporates a presence sensor 40, of the capacitive type, described in more detail below.

[0042] In use, the presence sensor 40 communicates with a central control unit, not shown, configured to control the locking and / or unlocking of at least one vehicle opening. In particular, said control unit is advantageously configured to control the locking and / or unlocking of the door receiving the handle 10, in response to immediate user presence information, said information being provided by the presence sensor 40.

[0043] The presence sensor 40, schematically represented in [Fig.2], is described in more detail below.

[0044] The presence sensor 40 is a capacitive type sensor, which comprises: - at least one electrode 41, integrated on a printed circuit board 42 (for PCB for "printed circuit board" in English) and intended to form a measuring capacitor with a part of the user's body, preferably the hand; - a detection circuit 43 comprising capacitors and switches, integrated on the printed circuit board 42 and connected to the electrode 41; - a microcontroller 44, configured to control the detection circuit 43, and to perform voltage and / or current measurements at said detection circuit 43; and - an accelerometer 45, connected to the microcontroller 44, and integrated on the printed circuit board 44.

[0045] The electrode 41 and the detection circuit 43 will not be described in further detail hereafter, as these are elements well known to those skilled in the art specializing in capacitive presence sensors. In particular, in a known solution, the detection circuit 43 is connected to the electrode 41 and includes capacitors and switches which together form a differential capacitive voltage divider, or "DCVD".

[0046] The microcontroller 44 is configured, in a manner known per se in the field of capacitive presence sensors, to drive the detection circuit 43 as well as to perform voltage and / or current measurements at said detection circuit 43. Here, the microcontroller 44 is configured in particular to control the switches of the detection circuit 43 and to make measurements from instructions stored in its memory area.

[0047] Advantageously, the microcontroller 44 is integrated into the handle 10, preferably integrated directly onto the printed circuit board 42.

[0048] The accelerometer 45 is, for example, based on piezoelectric sensing, capacitive sensing, inductive sensing, a strain gauge, etc. It is mounted integrally with the printed circuit board 42, fixed relative to it. Consequently, the accelerometer 45 is fixed relative to the electrode 41.

[0049] Preferably, the accelerometer 45 is sensitive, at least, to accelerations oriented along an axis of interest Al.

[0050] The presence sensor 40 is configured so that, in use, the axis of interest Al is substantially parallel to a translation axis of the electrode 41 when the handle 10 changes position between its rest position and its gripping position. By substantially parallel, we mean an angular deviation of 30° or less in absolute value between the axis Al and said translation axis, or even 15° or less, or even 5° or less.

[0051] In practice, this translation axis is advantageously orthogonal to the (xy) plane of the printed circuit board 42. In the example shown in the figures, the translation axis of the electrode 41 is considered to be oriented along the (z) axis, orthogonal to the (xy) plane of the printed circuit board 42, and the axis of interest Al extends along the (z) axis.

[0052] In use, the axis of interest Al is advantageously substantially orthogonal to a plane of the door panel receiving the external surface 21. By substantially orthogonal, we mean an angular deviation of 30° or less in absolute value between the axis Al and the normal to said plane of the door panel, or even 15° or less, or even 5° or less.

[0053] In use, the accelerometer 45 transmits in real time, to the microcontroller 44, measured acceleration data, or acceleration signal.

[0054] The microcontroller 44 is configured to determine information 401 relating to a presence detection, from voltage and / or current measurements taken at said detection circuit 43, as well as from the acceleration signal provided by the accelerometer 45.

[0055] In practice, this data advantageously relates to a tilting of the handle 10 from one position to the other, between its rest position and its gripping position.

[0056] The graph at the top of [Fig.3] schematically illustrates a variation, as a function of time t, of the position FDH_P of the printed circuit board 42.

[0057] At time t=0, the handle 10 is in the rest position, which corresponds to a Position PI of the printed circuit board in the vehicle's frame of reference, and more specifically in the frame of reference of the door panel comprising the external surface 21. During the time interval T1, the handle 10 tilts from its rest position PI to its gripping position P2. The handle 10 then remains for a certain duration in its gripping position P2, before returning to its rest position, the tilting occurring in a time interval T2.

[0058] The middle graph on [Fig.3] schematically illustrates the corresponding variation, as a function of time t, of the capacitance CAPA of the measuring capacitor formed by the electrode 41, without any change in the environment other than the positional tilts of the handle 10. The graph shows that, when the handle 10 tilts from one position to another between its rest position PI and its gripping position P, the value of capacitance CAPA changes from a value Cl to a value C2, and vice versa.

[0059] This graph illustrates the fact that, when the handle 10 tilts from one position to another, this results in a change in the capacitance of the measuring capacitor formed by the electrode 41, which is due to the movement of the electrode 41 relative to the large metallic mass formed by the door panel all around the handle 10. It is understood that this change in capacitance can be misinterpreted as the approach of the user's hand against the handle 10.

[0060] The lower graph in [Fig.3] schematically illustrates the acceleration signal ACC as a function of time, as supplied to the microcontroller 44 by the accelerometer 45. The graph shows that, when the handle 10 flips from one position to another between its rest position PI and its gripping position P, the acceleration signal has a peak (positive or negative, depending on whether the flip is from position PI to position P2, or vice versa).

[0061] The invention therefore proposes to configure the microcontroller 44 so that it receives, in addition to the CAPA capacitance signal, the ACC acceleration signal (in other words information relating to a deployment / retraction of the handle 10), and so that the microcontroller 44 takes into account these two signals for the determination of the information 401 relating to a presence detection.

[0062] Advantageously, the microcontroller 44 is configured to implement the following steps: - construction of the CAPA signal illustrated in [Fig.3], corresponding to an initial signal representative of an evolution, as a function of time, of the electrical capacitance of the measuring capacitor formed by the electrode 41; - using the ACC acceleration signal illustrated in [Fig.3], construction of a corrected signal (not shown), by removing from the CAPA signal variations in electrical capacitance concomitant with a peak in the ACC acceleration signal; and - determination of information 401 relating to a presence detection, from the corrected signal.

[0063] Information 401 relating to a presence detection may consist of said corrected signal in its entirety, or of data extracted from this signal.

[0064] The microcontroller 44 thus provides, as output, information 401 corrected for detection errors due to the switching of the handle 10 from one position to another rather than to the approach or movement of a part of the user's body. The information provided by the presence sensor 40 is therefore directly consolidated information, which requires no further processing to eliminate such detection errors.

[0065] The presence sensor 40 is advantageously configured to send the information 401 to a central control unit (not shown) capable of controlling the locking and / or unlocking of at least one opening of the motor vehicle. The correction of detection errors due to the tilting of the handle 10 has been performed directly at the presence sensor 40. It is therefore not necessary to adapt this central control unit to implement such error correction. It is thus understood that the invention offers considerable freedom in terms of compatibility between the central control unit and the technology used for the door handle, since it is not necessary to adapt the central control unit according to the type of door handle.

Claims

Claims

1. Presence sensor (40) of capacitive type, intended to be integrated in a motorized flush door handle (10) of a motor vehicle, and comprising: - at least one measuring electrode (41), integrated on a printed circuit board (42) and intended to form a measuring capacitor with a part of the body of a human operator; - a detection circuit (43) comprising capacitors and switches, integrated on the same printed circuit board (42) and connected to the at least one measuring electrode (41); and - a microcontroller (44), configured to control the detection circuit (43), to carry out voltage and / or current measurements on said detection circuit, and to determine, from said measurements, information (401) relating to a presence detection;characterized in that it further comprises an accelerometer (45) connected to the microcontroller (44), in that said accelerometer (45) is integrated on the printed circuit board (42), and in that the microcontroller (44) is configured to determine the information (401) relating to a presence detection by further using an acceleration signal (ACC) provided by the accelerometer (45).;

2. Presence sensor (40) according to claim 1, in which the microcontroller (44) is configured to implement the following steps: - construction of an initial signal (CAPA) representative of an evolution, as a function of time, of the electrical capacitance of the measuring capacitor; - construction of a corrected signal, by removing from the initial signal (CAPA) variations in electrical capacitance concomitant with a peak of the acceleration signal (ACC); and - determination of the information (401) relating to a presence detection, from said corrected signal.

3. Presence sensor (40) according to claim 1 or 2, in which the accelerometer (45) is sensitive to accelerations along at least one axis, in particular an axis called the axis of interest (Al), the axis of interest (Al) being inclined by at most 30° relative to a translation axis of the measuring electrode (41), in use in a motorized flush door handle (10) being tilted between a rest position and a gripping position.

4. Presence sensor (40) according to claim 3, wherein said axis of interest (Al) is inclined by at most 30° relative to the normal to the plane of the printed circuit board (42).

5. Presence sensor (40) according to any one of claims 1 to 4, configured to send the information (401) relating to a presence detection to a central computer capable of controlling a locking and / or an unlocking of at least one opening of the motor vehicle.

6. Motor vehicle door provided with a motorized flush door handle (10), and a main body panel, and in which: - the motorized flush door handle (10) is able to move between a rest position and a gripping position; - the motorized flush door handle (10) receives a presence sensor according to any one of claims 1 to 5, movable relative to the main panel during a change between the rest position and the gripping position of the motorized flush door handle.

7. Method implemented in the microcontroller (44) of a presence sensor (40) according to any one of claims 1 to 5, comprising the following steps: - construction of an initial signal (CAPA) representative of a change, as a function of time, in the electrical capacitance of the measuring capacitor; - construction of a corrected signal, by removing from the initial signal (CAPA) variations in electrical capacitance concomitant with a peak in the acceleration signal (ACC); and - determination of the information (401) relating to a presence detection, from the corrected signal.

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