Capacitive presence sensor for motorized flush door handle
By integrating an accelerometer with the capacitive presence sensor in motorized flush door handles, the system corrects for false detections caused by handle movement, improving detection accuracy and compatibility with central computer systems.
Patent Information
- Application Number
- FR2023007139
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-07-05
- Publication Date
- 2025-05-23
- Estimated Expiration
- 2043-07-05
AI Technical Summary
Capacitive presence sensors in motorized flush door handles often experience false detections due to the movement of the measuring electrode relative to the metal door panel, which can confuse handle deployment with user hand presence.
Integration of an accelerometer with the capacitive presence sensor on the same printed circuit board, allowing the microcontroller to correct signal variations caused by handle movement, thereby improving detection accuracy.
The solution provides a robust and autonomous correction of detection errors directly at the presence sensor, eliminating the need for additional mechanical switches and central computer adaptations, thus enhancing compatibility and reliability.
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Abstract
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 handles of the openings, in order to detect the presence of the hand of a user of the vehicle and thus unlock the openings.
[0003] Such detection is possible because the proximity of a part of the human body increases the electrostatic field. This electrostatic field varies the capacitance value of a measuring capacitor formed by a measuring electrode. Thus, a sudden variation 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 industry.
[0005] A motorized flush door handle, or “flush” handle, is a door handle capable of taking, in use, at least two positions among: - a rest position, in which it is flush with the external 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 brought from one position to another by means of a motor unit which comprises an electric motor and its control system. We therefore speak of a motorized flush handle.
[0007] By "flush with the external surface of the door", we mean 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 a 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, we can simply speak of handle, or door handle, to designate the flush door handle motorized.
[0009] In the gripping position, at least part of the handle is arranged offset relative to the external surface of the door. This may be offset towards the outside of the vehicle. The gripping position then corresponds to a deployed position of the handle, in which at least part of the handle projects relative to the external surface of the door, towards the outside of the vehicle. Alternatively, this may be offset towards the inside of the vehicle, part of the handle moving towards the inside of the vehicle so as to free access to a housing into which the user's hand is inserted to operate the handle.
[0010] The transition from one position to the other is advantageously controlled by a central computer, in response to a predetermined detection. This involves, for example, detection of the entry of an authorized user into a predetermined perimeter, via two-way communication between a vehicle communication module and an electronic key implemented in a dedicated badge (keyfob) or even in a smartphone.
[0011] Advantageously, once the door handle has moved into the deployed position, a presence sensor mounted in the handle makes it possible to detect the presence of the user's hand, so as to unlock the openings when the hand is in the immediate vicinity of said handle.
[0012] When a capacitive type presence sensor is thus mounted in the flush door handle, the measuring electrode will therefore move relative to the remainder of the door at the time of deployment or folding of the handle. More particularly, the measuring electrode will move relative to a large metal part formed by the door panel, which will impact the capacitance value of the measuring capacitor. This can generate false detections at the presence sensor, for example by confusing the presence of the user's hand in the immediate vicinity of the sensor with a simple deployment or folding of the flush door handle.
[0013] Solutions are known in the prior art based on signal processing subsequent to detection. In particular, a central computer is connected both to the capacitive type presence sensor and to a mechanical switch taking an open or closed position depending on whether the handle is in the folded or deployed position. The capacitive type presence sensor provides the central computer with a raw signal, representing the evolution over time 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 concomitant with a change in 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. Statement of the invention
[0015] This objective is achieved with a capacitive type 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 the at least one measuring electrode; and - a microcontroller, configured to control the detection circuit, to carry out voltage and / or current measurements on said detection circuit, and to determine, from said measurements, information relating to 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 integrally together. In use, 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 provided directly to the microcontroller of the presence sensor. The latter is thus capable of directly integrating this data into presence detection information.
[0019] The invention thus offers a completely autonomous solution, making it possible to overcome detection errors when a capacitive type presence sensor is mounted in a motorized flush door handle. In particular, it is no longer necessary to provide independent sensors of the mechanical switch type. Above all, it is no longer necessary to adapt the central computer, so as to allow it to receive information from these mechanical switches, and so that it corrects a raw signal so as to ignore a presence detection concomitant with a change in position of the mechanical switch. Indeed, this correction is made 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 use of 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 capacity of the measuring capacitor; - construction of a corrected signal, by removing from the initial signal variations in electrical capacity concomitant 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 by at most 30° relative to a translation axis of the measuring electrode, in use in a motorized flush door handle being tilted between a rest position and a gripping position.
[0023] Advantageously, said axis of interest is inclined by 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 information 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.
[0025] The invention also covers an automobile vehicle door provided with a motorized flush door handle and a main body panel, and in which: - the motorized flush door handle is able to move between a rest position and a grasping position; - the motorized flush door handle receives a presence sensor according to the invention, movable relative to the main body panel when changing between the rest position and the grasping 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 capacity concomitant with a peak in the acceleration signal; and - determination of information relating to a presence detection, from the corrected signal. Description of the figures
[0027] Other characteristics and advantages of the invention will become apparent from reading the description which follows. This description is purely illustrative and should be read in conjunction with the appended drawings in which:
[0028] [Fig.lA] [Fig.lA] schematically illustrates a motorized flush door handle, in a retracted position;
[0029] [Fig.lB] [Fig.lB] 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 reference frame (xyz) have been shown in at least some of the figures.
[0034] First of all, with reference to FIGS. 1A and 1B, 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 taking, in use, at least two positions among: - a rest 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 1A and 1B, the handle 10 deploys towards the outside of the vehicle.
[0037] In [Fig. 1 A], the handle 10 is shown in the rest position. It is housed inside a housing 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. 1B], 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 comprises a motor electric and its control system. The motor unit 30 is configured to bring 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 a detection of the entry of an authorized user into a predetermined perimeter, via a two-way communication between a communication module of 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 computer, not shown, configured to control locking and / or unlocking of at least one opening of the vehicle. In particular, said computer is advantageously configured to control locking and / or unlocking of the door receiving the handle 10, in response to immediate presence information from a user, said information being provided by the presence sensor 40.
[0043] The presence sensor 40, shown schematically 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 (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 carry out voltage and / or current measurements at the level of 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 more detail below, since they are elements well known to those skilled in the art specializing in the field of capacitive type presence sensors. In particular, in a known solution, the detection circuit 43 is connected to the electrode 41, and comprises capacitors and switches together forming a differential capacitive voltage divider, or “DCVD” (for the English “Differential Capacitive Voltage Divider”).
[0046] The microcontroller 44 is configured, in a manner known per se in the field of capacitive type presence sensors, to control the detection circuit 43 as well as to carry out 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 detection, on capacitive detection, on inductive detection, on a strain gauge, etc. It is mounted integral with the printed circuit board 42, fixed relative to the latter. Consequently, the accelerometer 45 is mounted fixed relative to the electrode 41.
[0049] Preferably, the accelerometer 45 is sensitive, at least, to accelerations oriented along an axis of interest A1.
[0050] The presence sensor 40 is configured so that, in use, the axis of interest A1 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 difference of 30° or less in absolute value between the axis A1 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 plane (xy) of the printed circuit board 42. In the example presented in the figures, it is considered that the translation axis of the electrode 41 is oriented along the axis (z), orthogonal to the plane (xy) of the printed circuit board 42, and that the axis of interest A1 extends along the axis (z).
[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 difference 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 recorded at the level of said detection circuit 43, as well as from the acceleration signal provided by the accelerometer 45.
[0055] In practice, these data advantageously relate to a switching from one position to the other of the handle 10, 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 frame of reference, and more particularly in the frame of reference of the door panel comprising the external surface 21. During the time interval T1, the handle 10 switches 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 switching taking place in a time interval T2.
[0058] The middle graph in [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 modification in the environment other than the position switches of the handle 10. The graph shows that, when the handle 10 switches from one position to the other among its rest position PI and its gripping position P, the capacitance value CAPA changes from a value C1 to a value C2, and vice versa.
[0059] This graph illustrates the fact that, when the handle 10 tilts from one position to the other, this results in a variation in the capacitance of the measuring capacitor formed by the electrode 41 which is due to the movement of the electrode 41 relative to this large metal mass formed by the door panel all around the handle 10. It is understood that this variation in capacitance can be interpreted, wrongly, as the approach of the user's hand against the handle 10.
[0060] The bottom 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 switches between its rest position PI and its gripping position P, the acceleration signal exhibits a peak (positive or negative, depending on whether the switch is made 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 capacity signal CAPA, the acceleration signal ACC (in other words information relating to a deployment / folding of the handle 10), and so that the microcontroller 44 takes these two signals into account 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 capacity concomitant with a peak in the ACC acceleration signal; and - determination of information 401 relating to a presence detection, from the corrected signal.
[0063] The information 401 relating to a presence detection can be constituted by said corrected signal in its entirety, or by data extracted from this signal.
[0064] The microcontroller 44 thus provides, at output, information 401 corrected for detection errors due to the switching from one position to another of the handle 10 rather than to an approach or a move away of a part of the user's body. The information provided by the presence sensor 40 is therefore directly consolidated information, which does not require any subsequent processing to overcome such detection errors.
[0065] The presence sensor 40 is advantageously configured to send the information 401 to a central computer (not shown) capable of controlling a locking and / or an unlocking of at least one opening of the motor vehicle. The correction of the detection errors due to the tilting of the handle 10 has been carried out directly at the level of the presence sensor 40. It is therefore not necessary to adapt this central computer so that it implements such an error correction. It is therefore understood that the invention offers great freedom in terms of compatibility between the central computer and the technology used for the door handle, since it is not necessary to provide an adaptation of the central computer according to the type of door handle.
Claims
Claims
1. A capacitive type 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) 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 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 the corrected signal.