CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase of International Application No. PCT/EP2019/072231 filed Aug. 20, 2019 which designated the U.S. and claims priority to FR 1857897 filed Sep. 3, 2018, the entire contents of each of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Field of the Invention

The invention pertains to the field of motor vehicles and vehicles in general, and relates to a device and to a method for detecting a user's intention to lock or unlock a motor vehicle opening element, this device being integrated into a handle of the opening element.

Description of the Related Art

Handles of vehicle opening elements, such as door handles, may be fitted with a device for detecting intention to lock or unlock in order to transmit, to the units for controlling the locks of the vehicle, information for commanding the opening or closure of the vehicle. These detection devices are required for implementing various locking systems commonly used in vehicles, such as “hands-free” systems, systems with deployable handles, or even electrically assisted systems.

“Hands-free” systems detect the presence of a remote-control access “hands-free” electronic fob, carried by the user, close to the vehicle. The detection of this fob at the same time as the detection of intention to lock or unlock respectively triggers locking or unlocking of the opening elements of the vehicle.

Systems with deployable handles use handles that are flush with the surface of the vehicle body, so as to be fully integrated in line with the vehicle. The detection of intention to lock or unlock in this case triggers a mechanism that activates the handle by deploying it so that the handle protrudes from the vehicle body and is then able to be grasped by the user.

Electrically assisted systems use vehicle opening elements whose opening or closing movement is motorized. The detection of intention to lock or unlock in this case triggers not only locking or unlocking of the opening element, but also a closing or opening movement of the opening element in question.

The systems listed above by way of example require a device for detecting intention to lock or unlock that is reliable, accurate, and which avoids false detections.

Patent application FR3044037 describes a device for detecting intention to lock or unlock, which comprises, inter alia, an inductive sensor in order to improve detection reliability. This detection device comprises:an inductive sensor that comprises an LC resonant circuit consisting of a coil and one or two capacitors;a handle target located facing the coil, this target being able to move from a rest position to a displaced position, under the effect of the user pressing on the handle, the distance between the coil and the handle target being modified between the rest position and the displaced position;a microcontroller equipped with means for measuring the resonant frequency of the LC resonant circuit.

SUMMARY OF THE INVENTION

The invention aims to improve devices for detecting intention to lock or unlock having an inductive sensor from the prior art by proposing a device of this type whose detection reliability is further improved.

To this end, the invention targets a device for detecting a user's intention to lock or unlock a motor vehicle opening element, this device being integrated into a handle, comprising:an inductive sensor that comprises an LC resonant circuit consisting at least of a coil and a main capacitor;a handle target located facing the coil, this target being able to move from a rest position to a displaced position, under the effect of the user pressing on the handle, the distance between the coil and the handle target being modified between the rest position and the displaced position;a microcontroller equipped with means for measuring the resonant frequency of the LC resonant circuit.

This device furthermore comprises an adjustment device for adjusting the value of the total capacitance of the LC resonant circuit, this adjustment device providing at least two different total capacitance values for the LC resonant circuit.

Such a device makes it possible to modulate the capacitance value of the LC resonant circuit in order to adapt it to external physical constraints that in particular modify the position of the handle target. These physical constraints are for example mechanical construction tolerances and dispersions that cause uncertainty as to the exact position of the handle target with respect to the coil. Another example of a physical constraint is the temperature, which causes the parts forming the handle to expand, and which may thus change the distance between the handle target and the coil, just as it may change the value of the electronic components.

The modulation of the value of the capacitance of the LC circuit leads to the resonant frequency of this circuit being modified, thereby allowing the microcontroller to operate at an optimum resonant frequency.

Another subject of the invention targets a method for calibrating a detection device as described above, a step of actuating the adjustment device in order to modify the total capacitance of the LC resonant circuit.

Such a calibration method makes it possible to adapt the capacitance value of the LC circuit so that the resonant frequency of the LC circuit is optimum with regard in particular to the microcontroller that is used and the real physical constraints that apply at the time of the calibration.

According to one preferred feature, the method comprises the following steps:measuring the resonant frequency for each total capacitance value of the LC resonant circuit provided by the adjustment device;identifying the measured resonant frequency values that are in the saturation region of the microcontroller, these resonant frequency values being substantially equal and corresponding to the saturation frequency of the microcontroller;identifying the first measured resonant frequency value that is outside the saturation region of the microcontroller, and identifying the corresponding optimum configuration of the adjustment device;applying said optimum configuration to the adjustment device so that the LC resonant circuit has a resonant frequency corresponding to said first measured resonant frequency value that is outside the saturation region of the microcontroller.

This method makes it possible to place the resonant frequency of the LC circuit precisely at an optimum value that is the maximum value of the resonant frequency before saturation of the microcontroller that is used.

Maximum sensitivity of the device for detecting intention to lock or unlock is thus achieved. This maximum sensitivity makes it possible to finely adjust the detection thresholds of the device, which thus exhibits improved detection reliability.

The detection device may comprise the following additional characteristics, on their own or in combination:the adjustment device comprises at least one adjustment capacitor as well as linking means, located in the microcontroller, for linking the adjustment capacitor to the main capacitor, these linking means being able to move between a neutral position in which the adjustment capacitor is disconnected, the LC resonant circuit thus having a first total capacitance value, and an adjustment position in which the adjustment capacitor is placed in a circuit with the main capacitor, the LC resonant circuit thus having a second total capacitance value; the placing in a circuit may for example consist in placing the adjustment capacitor in series or in parallel with the main capacitor;the adjustment device comprises between three and five adjustment capacitors and the corresponding linking means;the microcontroller comprises a frequency measurement input for measuring the resonant frequency of the LC resonant circuit;the linking means comprise a switch designed to disconnect the corresponding adjustment capacitor or to connect this adjustment capacitor from or to ground; the adjustment capacitor may be disconnected and connected to ground by disconnecting or connecting a single terminal of the capacitor from or to ground, the other terminal remaining permanently connected to the LC resonant circuit;the LC resonant circuit comprises two main capacitors connected firstly to the LC resonant circuit and connected secondly to ground.

The method for calibrating the detection device may comprise the following additional features, on their own or in combination:it comprises a step of storing the saturation frequency of the microcontroller;the calibration method is implemented when the resonant frequency of the LC resonant circuit is a value less than a predetermined value away from the saturation frequency of the microcontroller;in the step of identifying the first measured resonant frequency value that is outside the saturation region of the microcontroller, this first frequency value is identified with a predetermined safety margin;the method is implemented when the detection device is switched on, whether this is only when it is switched on for the first time or each time it is switched on;the method is implemented when the temperature varies beyond a predetermined limit since the last implementation of the method;the method is implemented periodically, with a predetermined period.

