Method and related detection device for opening a motor vehicle opening component by motion detection using Doppler radar

Abstract

The present invention proposes a method for opening an opening part of a motor vehicle (V), the vehicle (V) being equipped with a detection device (D) for detecting a predetermined movement of a user's body part, the method being characterized in that it comprises the following steps: • The device is pre-equipped with two Doppler radars, the first radar (R1) being adapted to emit waves toward the rear of the vehicle (V), the second radar (R2) being adapted to emit waves toward the ground (V), each radar comprising an antenna (A1), a radar wave transceiver (10), and a reflected radar wave processing device (20) adapted to detect the predetermined movement; • At a set frequency, for each radar (R1, R2), the phase component (I1, I2) and the phase shift component (Q1, Q2) of the reflected wave are measured; • For each radar, a characteristic parameter (A1, A2, F1, F2) of at least one of the two components is determined; • For each radar, the characteristic parameter is compared with a predetermined shape comprising a predetermined number of peaks, the characteristic value (Per) of the peak being greater than a predetermined duration threshold; • If the first and second radar characteristic parameters have a predetermined shape in the same interval of interest (Δt), • and if in said interval of interest the first radar also has a predetermined amount of phase change between the phase component and the phase shift component, • then a predetermined movement is detected and the opening component is opened, otherwise, the opening component is not opened.

Description

Technical Field

[0001] The present invention relates to a method for opening / closing an opening member and enabling safe hands-free entry by detecting the movement of a user's lower limbs using a Doppler radar. Background Art

[0002] A main, but not exclusive, application of the invention relates to the opening of a vehicle trunk, enabling an authorized user to open the trunk simply by a foot movement, wherein the user is identified by means of a BCM control module located in the vehicle, by means of a badge or key carried by the user.

[0003] Until now, hands-free entry requests have mainly consisted of a request to locate a hand to confirm opening / closing a vehicle access feature, and the process consists of two main steps: identification by the entry system's BCM of a key or badge authorized to open or close the vehicle in the vicinity of the access feature, and, in the case of an opening request, detection of the presence of a hand on the handle.

[0004] The implementation of this method requires an antenna for detecting an authorized key or badge, a presence sensor in the handle for detecting a hand (usually a capacitive sensor), and a central management system for managing hands-free entry requests, which may be, for example, a computer fully or partially dedicated to this function.

[0005] Regarding the contactless opening using the foot, one known application involves hospital staff opening the door of an operating room. For example, utility model CN ​​202 143 044 proposes equipping the door with an inductive sensor for detecting the foot. A person who wishes to enter or leave the room places his foot near the sensor, and the signal detected by the sensor is transmitted to a device for controlling the opening / closing mechanism of the door.

[0006] In the international application WO 2012 / 052210, it is proposed to use the foot for hands-free access to the trunk of a car. The document proposes to detect the movement of a body part of the user (e.g. the foot) by means of a capacitive detection assembly with two elongated electrodes. These electrodes extend horizontally under the trunk, the longer electrode under the shorter electrode, and are coupled to a control and evaluation device. The capacitance change is tracked relative to a reference potential, and when the movement is within the detection interval, an activation is triggered, for example, opening the trunk.

[0007] However, the use of capacitive sensors has certain major drawbacks. In particular, capacitive sensors are sensitive to external disturbances (rain, snow, etc.). In the context of hands-free access requests by detecting a hand, the management of vehicle opening components has been improved to combat various disturbances. For example, patent document FR 2 827 064 aims to identify disturbances caused by the metallic paint of a car, using a module that interprets the duration of the received signal logically.

[0008] A solution to the electromagnetic interference problem is described in patent document FR 2 915 331. It proposes to temporally filter the signal from the sensor of the handle of the opening member in order to verify the presence of a hand on the handle before verifying the opening request.

[0009] Therefore, the current state of the art hands-free opening / closing systems offer user-perceived comfort by confirming the opening / closing of a given opening part either by the presence of a hand or by the movement of a foot. However, false detections caused by interferences such as those caused by atmospheric phenomena (especially rain) or other types of interferences (electromagnetic interference, objects rolling under the bumper, etc.) cannot be identified and accidentally trigger false opening requests. For opening / closing by hand, there are solutions to mitigate certain interferences, but for foot movement detection systems, there is no reliable solution. Although in the latter case the detection system is based on two sensors per opening part, this system is not reliable enough in noisy environments.

[0010] It is therefore known to use Doppler radars instead of capacitive sensors. The detection of a predetermined movement of the lower extremity of the user's body is achieved by emitting radar waves directed to the rear of the vehicle (for example, the radar may be located in the rear bumper of the vehicle) and by analyzing the waves reflected by the user's presence. The analysis of the reflected waves enables the movement to be determined dynamically: the distance of the user relative to the radar, the speed and the form of the movement. The detection of the predetermined movement triggers the opening of the trunk.

[0011] However, one major drawback of Doppler radars according to the prior art is the accuracy, reliability and robustness of the detection of the intended movement. In particular, the detection of the Doppler radar is unreliable when the user's lower leg moves back and forth in the direction of the bumper and his feet brush the ground during this movement. The detection of the Doppler radar is also not able to robustly distinguish the intended movement from the movement of the lower leg of a user who passes by or paces near the vehicle but does not wish to open his trunk.

[0012] Therefore, the present invention proposes a method for opening an opening member which uses two Doppler radars in an optimized manner, thereby making it possible to mitigate the disadvantages of the prior art. In particular, the method for opening an opening member according to the present invention makes it possible to detect a predetermined movement in a reliable and robust manner. Summary of the invention

[0013] The present invention proposes a method for opening an opening member of a motor vehicle, the vehicle being equipped with a detection device for detecting a predetermined movement of a user's body part, the method being noteworthy in that it comprises the following steps:

[0014] • the device is pre-equipped with two Doppler radars, the first radar being adapted to emit waves toward the rear of the vehicle and the second radar being adapted to emit waves toward the ground, each radar comprising an antenna, radar wave transceiver means, and reflected radar wave processing means adapted to detect a predetermined motion,

[0015] • At the set frequency, for each radar, measure the phase component and phase shift component of the reflected wave,

[0016] • For each radar, determine the characteristic parameters of at least one of the two components;

[0017] • for each radar, comparing the characteristic parameter with a predetermined shape comprising a predetermined number of peaks, the characteristic value of which is greater than a predetermined persistence value threshold,

[0018] • If the characteristic parameters for the first radar and the second radar have a predetermined shape in the same region of interest,

[0019] • and if the first radar also has a phase change of a predetermined amount between the phase component and the phase shift component in said interval of interest,

[0020] • The predetermined movement is detected and the opening part opens,

[0021] • Otherwise, the opening part is not opened.

[0022] In a second embodiment, if the first radar has a predetermined amount of phase change between the phase component and the phase shift component, the method comprises the following additional steps:

[0023] • In the interval of interest, the amplitude of one of the two components of the second radar is compared with the minimum amplitude, and if the amplitude is greater than the minimum amplitude, then

[0024] • Detects the intended movement and opens the opening part,

[0025] otherwise

[0026] • if the second radar also has a phase change of a predetermined amount between the phase component and the phase shift component in said interval of interest,

[0027] • The predetermined movement is detected and the opening part opens.

[0028] Otherwise, the opening component is not opened.

[0029] Advantageously, the characteristic parameter of the phase component or the phase shift component is the amplitude or the frequency.

[0030] Preferably, the phase shift component is a phase quadrature component, shifted by an angle of 90° relative to the phase component.

[0031] Sensibly, the characteristic value of a spike is the persistence of the spike.

[0032] However, the characteristic value of the peak may also be the amplitude of the peak, or the integral of the peak value over time between the minimum value of the peak and the maximum value of the peak.

[0033] When the predetermined movement is a back and forth movement of a body part of the user towards the detection device, the predetermined number of phase changes is equal to one, and the predetermined number of peaks is equal to two.

[0034] The present invention also relates to a detection device for detecting a predetermined movement of a user's body part, which is adapted to be mounted in a motor vehicle. The device is noteworthy in that it includes two Doppler radars, the first radar is adapted to emit waves toward the rear of the vehicle, and the second radar is adapted to emit waves toward the ground, each radar includes an antenna, a radar wave transceiver, and a reflected radar wave processing device adapted to detect the predetermined movement, the processing device including:

[0035] • extraction means for extracting at least one physical parameter of the phase component or the phase shift component,

[0036] • a first comparison means for comparing the physical parameter with a predetermined shape comprising a predetermined number of peaks in the interval of interest, the characteristic values ​​of the peaks being greater than a threshold value,

[0037] • a first verification device for verifying the synchronization of a predetermined shape between two radars,

[0038] • And, for the first radar only:

[0039] • second verification means for verifying whether a predetermined amount of phase change exists between the phase component and the phase shift component in the interval of interest,

[0040] • An unlocking device for unlocking the opening member based on the results of the above comparison and verification.

[0041] In a second embodiment, the detection device further comprises:

[0042] • for the second radar, a second comparing means for comparing the amplitude of the phase component or the phase shift component with a minimum amplitude,

[0043] • for the second radar, a third verification device for verifying whether a predetermined amount of phase change exists between the phase component and the phase shift component in the interval of interest,

[0044] • An unlocking device for unlocking the opening member based on the results of the above comparison and verification.

[0045] Advantageously, the characteristic parameter of the phase component or the phase shift component is the amplitude or the frequency.

[0046] Sensibly, the phase shift component is the phase quadrature component, shifted by an angle of 90° with respect to the phase component.

[0047] Preferably, the characteristic value of the peak is the duration value of the peak.

[0048] However, the characteristic value of the peak may be the amplitude of the peak, or the integral of the amplitude of the peak between the minimum value of the peak and the maximum value of the peak over time.

[0049] When the predetermined movement is a back and forth movement of a body part of the user towards the detection device, the predetermined number of phase changes is equal to one, and the predetermined number of peaks is equal to two.

[0050] The invention is also applicable to any motor vehicle comprising a detection device according to any of the features listed above. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Other features and advantages of the present invention will become more apparent by reading the following description. This description is purely illustrative and should be read with reference to the accompanying drawings, in which:

[0052] Figure 1 A vehicle is schematically shown equipped with a detection device for detecting a predetermined movement of a user's body part according to the present invention, the detection device comprising two Doppler radars,

[0053] Figure 2 Schematically shows a first radar of a detection device according to the invention and its electronic components,

[0054] Figure 3 A radar wave transceiver device is schematically shown, which is connected to a first antenna A1 and also includes a phase and phase shift demodulation device according to the present invention,

[0055] Figure 4 The phase component I representing the phase change of the reflected wave and the phase quadrature component Q representing the change of the offset phase of the reflected wave with time t are shown.

[0056] Figure 5 is a flow chart showing the steps of the method for opening an opening member according to the present invention,

[0057] Figure 6 Eight graphs are included, the four right graphs relate to signals received by the first radar R1: the first graph illustrates the original signal of the Doppler radar of the phase component I1 and the phase shift component Q1, the second graph illustrates the amplitude of the phase component I1, the third graph illustrates the frequency F1 of the phase component, and the fourth graph illustrates the phase change φ1 between the phase component I1 and the phase shift component Q1; and the four left graphs relate to signals received by the second radar R2: the first graph illustrates the original signal of the Doppler radar of the phase component I2 and the phase shift component Q2, the second graph illustrates the amplitude of the phase component I2, the third graph illustrates the frequency F2 of the phase component, and the fourth graph illustrates the phase change φ2 between the phase component I2 and the phase shift component Q2, all during a user performing a predetermined motion to unlock the trunk of his vehicle,

[0058] Figure 7 The invention comprises eight graphs, the four graphs on the right side relate to the signal received by the first radar R1: the first graph illustrates the original signal of the Doppler radar of the phase component I1' and the phase shift component Q1', the second graph illustrates the amplitude of the phase component I1', the third graph illustrates the frequency F1' of the phase component, and the fourth graph illustrates the phase change φ1' between the phase component I1' and the phase shift component Q1'; the four graphs on the left side relate to the signal received by the second radar R2: the first graph illustrates the original signal of the Doppler radar of the phase component I2' and the phase shift component Q2', the second graph illustrates the amplitude of the phase component I2', the third graph illustrates the frequency F2' of the phase component, and the fourth graph illustrates the phase change φ2' between the phase component I2' and the phase shift component Q2', all during the period when the user performs an interfering motion that is not suitable for unlocking the trunk of his vehicle,

[0059] Figure 8 The values ​​of the persistence values ​​calculated for five frequency peaks of the frequency signal of the first radar are schematically shown. DETAILED DESCRIPTION

[0060] Figure 1A motor vehicle V is shown, which is equipped with a detection device D according to the present invention for detecting a predetermined movement of a user's body part, which is intended to trigger the opening of an opening part, in this case, the opening part is specifically the trunk of the vehicle V. The detection device D is adapted to be mounted on the motor vehicle, and is preferably but not restrictively included in the rear bumper of the vehicle V. More specifically, the device includes two Doppler radars R1 and R2, each of which includes an antenna A1, a device for transmitting and receiving radar waves through the antenna A1, and a device for processing reflected radar waves to detect predetermined movements. The first radar R1 is adapted to emit radar waves directed to the rear of the vehicle. The second radar R2 is adapted to emit radar waves directed to the bottom of the vehicle, more precisely, to the ground. The two radars R1 and R2 are integrated in the bumper of the vehicle V, for example.

[0061] The predetermined motion may include a "kick" or back-and-forth motion of the user's lower leg toward the two radars, in this example specifically toward the bumper of the vehicle V. However, the present invention is applicable to any predetermined motion.

[0062] It is known in the prior art that processing of the radar waves emitted by a single radar and reflected by the presence of the user's body makes it possible to determine whether the user has made a predetermined movement and therefore whether he wishes to open the trunk of his vehicle. If the predetermined movement is detected, the opening of the trunk is triggered, which is known to those skilled in the art and will not be described in detail here. As mentioned above, the disadvantage of a Doppler radar is the lack of reliability and robustness of the detection.

[0063] Figure 2 A first radar R1 is shown, comprising a first antenna A1 connected to a transceiver device 10, which in turn is connected to a control unit 20. The control unit 20 and the transceiver device 10 are fed directly or indirectly with a voltage Vcc via the voltage of a battery of the vehicle V. A switching device s1 enables feeding of the transceiver device 10. A second radar R2 (not shown) comprises the same components as the first radar R1.

[0064] According to the present invention, Figure 3As shown, the transceiver 10 further includes a directional coupler 101 connected to the first antenna A1; two demodulators connected to the output of the directional coupler: a first demodulator 102 adapted to provide a phase component I1 as an output, the phase component I1 representing the phase change of the reflected wave received by the first antenna A1, and a second demodulator 103 adapted to provide a phase shift component Q1 as an output, the phase shift component Q1 representing the change of the offset phase of the reflected wave received by the first antenna A1. To this end, a phase shifter 104 is connected to the second demodulator 103. The directional coupler 101 enables the transceiver 10 to perform transceiver operations simultaneously, and enables the transmission signal to be separated from the reception signal, that is, the transmitted radar wave to be separated from the received radar wave. The output of the first demodulator 102 and the output of the phase shifter 104 are connected to the input of the directional coupler 101 and the oscillator 105 to generate a transmission signal to the first antenna A1. The second radar R2 (not shown) similarly includes a directional coupler, a first demodulator, a second demodulator, a phase shifter, and an oscillator.

[0065] When the radar wave is reflected by the user's body and received by the first antenna A1 via the directional coupler, the signal of the reflected wave is transmitted to the first demodulator 102, and the first demodulator 102 generates a phase component I1 indicating the phase of the wave. Figure 4 In the diagram shown, the phase component I1 is shown as a function of time. The phase component I1 is a sinusoidal shaped signal.

[0066] The signal of the reflected wave is also transmitted to the second demodulator 103, which generates a phase shift component Q1 representing the shifted phase of the wave. More precisely, the phase shift component Q1 is the image of the shifted phase component I1 at time t. Preferably, but not restrictively, the phase shift is an angular shift of 90°. The phase shift component is then called the phase quadrature component Q1. Figure 4 In the diagram shown, it is shown as a function of time t, so the phase quadrature component Q1 is also a sinusoidal shaped signal.

[0067] The signals representing the phase component I1 and the phase quadrature component Q1 are then provided to the control unit 20, which analyses the signals. For each radar, ie for the first radar R1 and for the second radar R2 respectively, the control unit 20 further comprises:

[0068] • extraction means M1 for extracting at least one physical parameter, such as the amplitude A1 (or A2) or the frequency F1 (or F2) of the phase component I1 (I2) or the phase shift component Q1 (Q2),

[0069] • a first comparison means M2 for comparing the physical parameters A1 (A2), F1 (F2) with a predetermined shape comprising a predetermined number of peaks in the interval of interest Δt, wherein the characteristic value (eg the duration value Per) of the peaks is greater than a threshold value,

[0070] • first verification means M3 for verifying the synchronization of a predetermined shape between the two radars R1, R2,

[0071] And only for the first radar R1:

[0072] • second verification means M4 for verifying whether there is a predetermined amount of phase change between the phase component I1 and the phase shift component Q1 in said interval of interest Δt,

[0073] • Unlocking device M5 for unlocking the opening member according to the result of the above comparison and verification.

[0074] The extraction means M1 , the first comparison means M2 , the first and second verification means M3 , M4 and the unlocking means M5 are partially or completely software means which may be included in the microcontroller.

[0075] In the second embodiment of the present invention, for the reflected wave and the received wave, only for the second radar R2, the control unit 20 further includes:

[0076] • a second comparison means M6 for comparing the amplitude A2 of the phase component I2 or the phase shift component Q2 with a predetermined amplitude,

[0077] • for the second radar R2, third verification means M7 for verifying whether a predetermined amount of phase change exists between the phase component I2 and the phase shift component Q2 in said interval of interest Δt,

[0078] • Unlocking device M8 for unlocking the opening member according to the result of the above comparison and verification.

[0079] The phase shift is preferably, but in no way restrictively, an angular offset between the phase component I1 (I2) and the phase quadrature component Q1 (Q2) of 90° (or π / 2). However, any other angular offset value between 0° and 180° may be envisaged.

[0080] Preferably, the predetermined number of phase changes is equal to one, as described below.

[0081] Figure 5 A method for opening a vehicle opening feature according to the present invention is shown and will now be described.

[0082] In a first embodiment of the method according to the invention, the first step E1 comprises: for each radar R1, R2, continuously measuring the phase component I1, I2 and the phase quadrature component Q1, Q2 of the reflected radar wave at a set frequency, and extracting characteristic parameters therefrom for at least one of the two components, such as:

[0083] • Amplitude A1, A2, or

[0084] • Frequencies F1, F2,

[0085] and the phase difference between the two components, namely the phase difference φ1, φ2 between the phase component I1 (or I2) and the phase quadrature component Q1 (or Q2). For the sake of clarity, in the rest of the text, the characteristic parameter used in the opening method according to the invention will consider the frequency F1 (or F2) of the phase component I1 (or I2), although it can also be the amplitude A1 (or A2) and / or the phase shift component Q1 (or Q2).

[0086] Next, in a second step E2, for each radar R1, R2, the characteristic parameter, namely the frequency F1 (F2) of the phase component I1 (I2), is compared with predetermined thresholds, which are at least one threshold, preferably two: a high threshold and a low threshold. The purpose of this step is to verify, for each of the two radars R1, R2, whether the characteristic parameter F1 (F2) of the phase component I1 (I2) follows a predetermined shape. This predetermined shape preferably resembles two consecutive peaks, or a double "bell curve". This Figure 6 In Figure 6 In FIG. 1 , the third graph from the top on the left illustrates characteristic parameters of the phase component I1 of the first radar R1 (frequency F1 in this example) in the case of a predetermined motion, and the third graph from the top on the right illustrates characteristic parameters of the phase component I2 of the second radar R2 (frequency F2 in this example). These frequencies F1, F2 each include two consecutive peaks. Figure 6 In FIG. 4 , two threshold values ​​S and S′ are shown, and the threshold values ​​between the characteristic parameters of the two radars R1 and R2 may be different.

[0087] If, for each radar R1, R2, the parameter representing the phase component I1, I2 (here the frequency F1, F2) follows a predetermined shape, in the present case crossing the first and second thresholds S, S' (greater than the first threshold S and the second threshold S' then successively less than the second threshold S', then greater than the second threshold and finally less than the first and second predetermined thresholds S, S'), then in a following step E3 it is verified for both radars R1, R2 whether the moment of crossing the upper and lower thresholds is included in the same predetermined time window or in the same time interval Δt. In step E3, the aim is to verify that the moment of crossing the upper and lower thresholds is substantially synchronized between the two radars R1, R2. Figure 6 In the third diagram on the left, t1 corresponds to the first moment when the frequency F1 crosses the first threshold S, which corresponds to the beginning of the predetermined shape; and t2 corresponds to the last moment when the frequency F1 becomes lower than the first threshold S, which corresponds to the end of the predetermined shape. The interval Δt between the first moment t1 and the last moment t2 will be called the interval of interest. "Synchronous" means that for both radars R1, R2, the predetermined shape lies in said interval of interest Δt (of course an error tolerance can be added). This is Figure 6 It is shown in Figure 6 In the third graph on the right, the moments when the upper and lower thresholds are crossed are located in the same interval of interest Δt.

[0088] Otherwise, if the instants at which the parameters representative of each radar R1 , R2 cross the threshold are not included in the same interval of interest Δt, in other words, if the frequencies F1 , F2 of the phase components of the two radars R1 , R2 do not have a synchronized predetermined shape, the method returns to the first step E1 .

[0089] If the predetermined shapes representing the parameters F1 , F2 are synchronized between the two radars R1 , R2 , in a subsequent step (step E4 ), in said interval of interest Δt, the number of peaks present is counted and also a characteristic value is calculated for each peak.

[0090] The characteristic value is preferably, but in no way restrictively, the duration value Per of the spike. The calculation of the duration value Per of the spike is known to a person skilled in the art and can be found in the scientific literature (http: / / www2.iap.fr / users / sousbie / web / html / indexd3dd.html post / Persistence-and-simplification,http: / / www.astro.rug.nl / ~weygaert / tim1publication / jigsaw / cohensteiner_jigsaw.pdf,https: / / geometr ica.saclay.inria.fr / team / Steve.Oudot / courses / EMA / Slides_intro.pdf, https: / / www.sthu.org / blog / 13-perstopology-peakdetection / index.htm). Figure 8 The duration of the spike is shown. Figure 8 The predetermined shape of the frequency F1 of the phase component I1 of the first radar R1 in the interval of interest Δt is shown. Five calculations of the persistence values ​​Per of the five peaks P1, P2, P3, P4 and P5 are also shown. The persistence value of the first peak P1 is equal to 81, the persistence value of the second peak P2 is equal to 0.28, the persistence value of the third peak P3 is equal to 51, the persistence value of the fourth peak P4 is equal to 8 and finally the persistence value of the fifth peak P5 is equal to 0.61. The two peaks with the highest persistence value Per are the first peak P1 and the third peak P3.

[0091] The characteristic value may also be the amplitude of the peak, or the integral over time of the value between the minimum value of the peak and the maximum value of the peak, or any other calculation that enables the assessment of the relative importance of the peak of the representative parameter with respect to other peaks present in the interval of interest Δt.

[0092] Once the number of peaks present in the time interval has been determined and characterized, for example, by their persistence value Per, it is verified in a step E5 for each radar R1, R2 that the number of peaks representing the parameter F1, F2 having a persistence value greater than a predetermined persistence value threshold is strictly less than a predetermined number Nb, for example 3. The purpose of this step E5 is to filter out any event that could generate multiple reflected waves (and therefore many peaks with high persistence values ​​Per), such as a person passing near the vehicle, or a user working on his car but not wishing to unlock the trunk of his vehicle V.

[0093] If, in the interval of interest Δt, the number of peaks having a persistence value Per greater than a predetermined persistence value threshold is strictly less than 3 (step E5), in the next step (step E6), it is verified whether a predetermined number of phase changes φ1 exist between the phase component I1 and the phase quadrature component Q1 only in the wave reflected and received by the first radar R1 (in the present case, the wave emitted by the first radar R1 towards the rear of the vehicle). Preferably, the predetermined number is equal to 1. This is in Figure 6 As shown in FIG. 1 , during the predetermined movement, Figure 6 The fourth diagram from the bottom left illustrates that there is only one phase change between the phase component I and the phase quadrature component Q, which is represented by a rising edge from a value of +1 to a value of -1. In the case where component Q1 is the phase quadrature component, the phase change φ1 can take the value -90° or +90°. Figure 6 In the fourth graph from the left, the phase change has been normalized to either -1 or + 1. Therefore, the phase change could be a rising edge from -1 to +1 or a falling edge from +1 to -1, depending on the direction of the phase shift calculation and the normalization chosen.

[0094] If the wave received by the first radar R1 comprises during the interval of interest Δt a predetermined number of phase changes φ1 (step E6 , in the present case only one phase change in this example), a predetermined movement is detected and unlocking of the trunk is actuated, otherwise, no predetermined movement is detected and the trunk remains locked.

[0095] In a preferred embodiment, after step E6, it is proposed to verify the presence of an atypical but valid predetermined movement, in the present case the movement of a passing foot, and to distinguish this movement from the movement of a “pedestrian” (i.e. an individual walking near the bumper but without performing the predetermined movement and who is unable to unlock the trunk of the vehicle V).

[0096] To this end, after detecting a predetermined amount of phase change φ1 in the reflected wave received by the first radar R1, an additional step is proposed, Figure 5 In the flowchart, it is represented by a dotted line.

[0097] Then, in step E7, it is verified whether the amplitude A2 of at least one of the two components of the wave received by the second radar R2 during said interval of interest Δt, for example the phase component I2 (or the phase shift component Q2), is greater than the minimum amplitude Amin (see Figure 6 second chart from the right).

[0098] If the amplitude A2 of one of the components of the wave received by the second radar R2 is greater than a predetermined amplitude Amin, a predetermined but atypical movement is detected and unlocking is actuated.

[0099] If, for example, the amplitude A2 of the phase component I2 of the second radar R2 is smaller than a predetermined amplitude during said interval of interest Δt, then in step E8 it is verified whether the wave received by the second radar R2 has a predetermined number of phase changes φ2 (in the present case, in this example, only one phase change) during said interval of interest Δt.

[0100] If the wave received by the second radar R2 has a single phase change φ2 during said interval of interest Δt, an atypical but valid predetermined movement is detected and unlocking is actuated, otherwise no atypical predetermined movement is detected and the luggage compartment remains locked.

[0101] This preferred embodiment enables movements of the foot sweeping over the ground type to be identified and in particular enables movements from eg pedestrians, ie individuals walking beside the detection device but not performing the intended movement, not to be considered as intended movements.

[0102] Therefore, in the first embodiment, cleverly, unlocking is performed only upon detection of an event detected synchronously by both radars and then upon analysis of the signal from the first radar R1 .

[0103] The second embodiment is then based on an improvement of the analysis of the signals from the two radars R1 , R2 in order to reject movements of the pedestrian type that would have been detected as valid by the first embodiment.

[0104] Figure 7 The first radar R1 (located at Figure 6 diagram on the left) and the second radar R2 (located at Figure 6 The right graph shows the signals of the phase components I1', I2' and the phase shift components Q1', Q2' of the received wave over time, the amplitudes A1', A2' and the frequencies F1', F2' of the phase components I1', I2', and the phase changes φ1', φ2' during the disturbance event caused by the user which is not the intended motion. The frequency F1' has a predetermined shape (in the form of two main peaks) during the interval of interest Δt', but the frequency F2' does not have a predetermined shape during the same interval of interest Δt'. Therefore, according to the example described and explained above, the motion is not the intended motion.

[0105] The ingenuity of the present invention therefore lies in that it alleviates the disadvantages of the prior art, the method for opening an opening member according to the present invention enabling reliable and robust detection by judicious and non-redundant use of signals from two Doppler radars arranged in a specific manner on the vehicle V, avoiding measurement redundancy.

Claims

1. A method for opening an opening member of a motor vehicle, the vehicle being equipped with a detection device for detecting a predetermined movement of a user's body part, the method being characterized in that it comprises the following steps: The device is pre-equipped with two Doppler radars, the first radar (R1) being adapted to transmit waves toward the rear of the vehicle, and the second radar (R2) being adapted to transmit waves toward the ground, each radar comprising an antenna (A1), a radar wave transceiver (10), and a reflected radar wave processing device (20) adapted to detect a predetermined motion, At the set frequency, for each radar (R1, R2), measure the phase component and phase shift component of the reflected wave, for each radar (R1, R2), determining a characteristic parameter (A1, A2, F1, F2) of at least one of the two components; for each radar (R1, R2), comparing the characteristic parameters (A1, A2, F1, F2) with a predetermined shape comprising a predetermined number of peaks, the characteristic values ​​of which are greater than a predetermined persistence value threshold, If the characteristic parameters (A1, A2, F1, F2) for the first and second radars (R1, R2) have a predetermined shape in the same interval of interest, and if in said interval of interest the first radar (R1) also has a phase change of a predetermined amount between the phase component and the phase shift component, ·Then the predetermined movement is detected and the opening part is opened, If the characteristic parameters (A1, A2, F1, F2) do not have a predetermined shape in the same interval of interest for the first and second radars (R1, R2), and if the first radar (R1) does not have a predetermined number of phase changes between the phase component and the phase shift component in said interval of interest, the opening means is not opened.

2. The method for opening an opening member of a motor vehicle according to claim 1, characterized in that: If the first radar (R1) has a phase change of a predetermined amount between the phase component and the phase shift component, the method is characterized in that it comprises the following additional steps: in the interval of interest, comparing the amplitude (A2) of one of the two components of the second radar (R2) with a minimum amplitude, and if the amplitude (A2) is greater than the minimum amplitude, detecting a predetermined movement and opening the opening means, In the interval of interest, compare the amplitude (A2) of one of the two components of the second radar (R2) with a minimum amplitude, and if the amplitude (A2) is not greater than the minimum amplitude, then If the second radar (R2) also has a phase change of a predetermined amount between the phase component and the phase shift component in the interval of interest, a predetermined movement is detected and the opening means is opened, If the second radar (R2) does not have a predetermined amount of phase change between the phase component and the phase shift component in the interval of interest, the enabling feature is not enabled.

3. The method for opening an opening member of a motor vehicle according to claim 1 or 2, characterized in that: The characteristic parameter of the phase component or phase shift component is the amplitude (A1, A2) or the frequency (F1, F2).

4. The method for opening an opening member of a motor vehicle according to claim 1 or 2, characterized in that: The phase shift component is a phase quadrature component that is shifted by 90° relative to the phase component.

5. The method for opening an opening member of a motor vehicle according to claim 1 or 2, characterized in that: The characteristic value of a spike is the duration of the spike.

6. The method for opening an opening member of a motor vehicle according to claim 1 or 2, characterized in that: The characteristic value of a spike is the amplitude of the spike, or the integral of the spike value over time between the minimum value of the spike and the maximum value of the spike.

7. The method for opening an opening member of a motor vehicle according to claim 1 or 2, characterized in that: In case the predetermined movement is a back and forth movement of a body part of the user towards the detection device, the predetermined number of phase changes is equal to one and the predetermined number of peaks is equal to two.

8. A detection device for detecting a predetermined movement of a user's body part, which is adapted to be mounted in a motor vehicle, the device being characterized in that it comprises two Doppler radars, the first radar (R1) being adapted to emit waves toward the rear of the vehicle, the second radar (R2) being adapted to emit waves toward the ground, each radar comprising an antenna (A1), a radar wave transceiver (10), and a reflected radar wave processing device (20) adapted to detect the predetermined movement, the processing device (20) comprising: extraction means (M1) for extracting at least one physical parameter (A1, A2, F1, F2) of a phase component or a phase shift component, a first comparison means (M2) for comparing, in the interval of interest, the physical parameters (A1, A2, F1, F2) with a predetermined shape comprising a predetermined number of peaks, the characteristic values ​​of which are greater than a threshold value, a first verification device (M3) for verifying the synchronization of a predetermined shape between the two radars (R1, R2), And, for the first radar (R1) only: second verification means (M4) for verifying whether a predetermined amount of phase change exists between the phase component and the phase shift component in the interval of interest, Unlocking means (M5) for unlocking the opening member according to the result of the comparison by the first comparing means (M2) and according to the result of the verification by the first verification means (M3) and the second verification means (M4).

9. The detection device according to claim 8, characterized in that: It also includes: for the second radar (R2), a second comparison device (M6) for comparing the amplitude (A2) of the phase component or the phase shift component with a minimum amplitude, for the second radar (R2), a third verification device (M7) for verifying whether a predetermined amount of phase change exists between the phase component and the phase shift component in the interval of interest, Unlocking means (M8) for unlocking the opening member according to the result of the comparison by the second comparing means (M6) and according to the result of the verification by the third verification means (M7).

10. The detection device according to claim 8 or 9, characterized in that: The characteristic parameter of the phase component or phase shift component is the amplitude (A1, A2) or the frequency (F1, F2).

11. The detection device according to claim 8 or 9, characterized in that: The phase shift component is a phase quadrature component that is shifted by 90° relative to the phase component.

12. The detection device according to claim 8 or 9, characterized in that: The characteristic value of a spike is the duration of the spike.

13. The detection device according to claim 10, characterized in that: The characteristic value of a spike is the amplitude of the spike, or the integral of the spike value over time between the minimum value of the spike and the maximum value of the spike.

14. The detection device according to claim 8 or 9, characterized in that: In case the predetermined movement is a back and forth movement of a body part of the user towards the detection device, the predetermined number of phase changes is equal to one and the predetermined number of peaks is equal to two.

15. A motor vehicle comprising a detection device according to any one of claims 8 to 14.

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