FR2778980A1 - Electromagnetic device having wireless position sensors for use with a vehicle central locking system - Google Patents

Abstract

Device comprises an arrangement of sensors on moving parts arranged on a first element e.g. the doors or boot of a car and a central module that receives information from position sensors on the moving parts and can tell the location and which part is transmitting information.- DETAILED DESCRIPTION - Device has a number of wireless electronic position sensors (1-4) for location of elements on a first component (P2) and a second assembly mounted on a second component (P1). The latter assembly comprises a principle module connected to a principal connector (J) over which data is received from the position sensors.Each sensor has a transponder interface and the module interface can determine which sensor is transmitting data to it

Description

ELECTROMECHANICAL DEVICE WITH DETECTORS

  POSITION, PARTICULARLY FOR LOCK ORDER

  ELECTRIC VEHICLE.

  The invention relates to an electromechanical device with position detectors for locating, by electrical information, the position of elements on a first part, this device comprising a first assembly intended to be mounted on the first part, this first assembly comprising sensors associated with the elements to be identified, and a second assembly intended to be mounted on a second part, this second assembly comprising a main module attached to a main connector on which the information is

  collected, a relative movement being possible between the two parts.

  In general, the electromechanical device of the invention applies to complex and small electromechanical systems, in particular in the automotive field, and more

  particularly in automotive locksmithing.

  The invention relates more particularly, but not exclusively, to such a device for controlling an electric lock of a motor vehicle. In this case the first part is constituted by an opening of the vehicle, for example a door or a trunk, and the second part is constituted by a chassis element of the vehicle. French patent application No. 97 13278 filed on October 23, 1997 in the name of the same Applicant Company concerns a

  electromechanical device of this type.

  The mechanisms, in particular the locks, used in motor vehicles today fulfill an ever increasing number of functions, and must allow the control of the accomplishment of these functions. This is why networks of tabs and / or plies and / or connection wires had to be put in place to travel through the product (mechanism or lock) along a delicate route, in order to electrically connect all the contactors or sensors. position to a main connector. This practice is not only restrictive but costly. It can also constitute an obstacle to the implementation of concepts of mechanisms

technically interesting.

  The invention aims, above all, to provide an electromechanical device comprising a set of sensors capable of exchanging, without electrical connection, information with the module

  main directly attached to the main connector.

  According to the invention, an electromechanical device with position detectors without electrical connections for locating, by electrical information, the position of elements on a first part, of the kind defined above, is characterized by the fact: - that at each sensor is associated with a transponder type interface suitable for wirelessly transmitting the information emitted by the sensor to the main module, - and that identification means are provided at each detector and the main module to enable this module

  to determine from which detector information received comes.

  According to a first embodiment, the identification means comprise: - for each detector, an arrangement giving it a natural resonance frequency, - and, for the main module, a variable frequency generator suitable for supplying the associated transponder by induction at

each sensor.

  Advantageously, each sensor and its associated transponder interface are part of the same housing and constitute a

single component.

  According to a first solution, the transponder associated with a sensor is a passive transponder. In particular, the transponder consists of a resonant circuit LC tuned to the frequency specific to the detector considered, and the sensor consists of a contactor mounted in the resonant circuit which can thus be closed in a loop or cut off depending on whether the contactor is closed or open. . The main module then includes a carrier generator delivering a frequency ramp varying from the lowest possible frequency to the highest. The carrier generator may include a voltage ramp generator connected to an oscillator emitting the carrier, so

  to obtain a carrier with progressively variable frequency.

  According to a variant, the transponder is active and includes a specific integrated circuit. The carrier generator then operates on a number of carrier frequencies equal to the number of detectors to be managed. Preferably, in the two cases defined above, the carrier is sent to the input of a transconductance amplifier whose output current is proportional to the input voltage, the output of this amplifier being connected to a terminal a transmitting coil, the other terminal of which is connected to ground, either directly for

  provide broadband transmission, either through a capacitor.

  A demodulator / low-pass filter is connected to the output terminal of the amplifier, and the output of the demodulator is connected to a

  threshold trigger circuit ("trigger" or Schmitt rocker).

  The link between the output of the demodulator and the input of the threshold-triggered circuit may include a switch

driven by the oscillator.

  Advantageously, the threshold trigger circuit is connected to the ramp generator so that the trigger threshold is modified in conjunction with the ramp, to bring the output signal flat.

of the circuit.

  According to another embodiment, all the resonant LC circuits of the transponder interfaces have the same resonant frequency, and the identification means for each transponder include a specific address code of a detector, stored in the main and own module to be selected and transmitted by this module in order to control a detector, an additional electronic device being provided in each transponder so that this transponder can only transmit if it has previously received the correct address code

sent by the main module.

  The main module is of the same type as defined above. The address code can be formed by amplitude modulation at a high rate, in particular 80% to 100%,

  applied by the main module to the carrier it transmits.

  Between the carrier generator and the amplifier, it is possible to insert a logic gate or a switch making it possible to generate short-term interruptions to achieve this modulation. The invention consists, apart from the arrangements set out above, of a certain number of other arrangements which will be more explicitly discussed below in connection with the embodiments described with reference to the appended drawing, these examples n being however

in no way limiting.

  In this drawing - Figure 1 is an overall diagram of an electromechanical device according to the invention; - Figure 2 is a diagram of a detector according to the invention; - Figure 3 is a more detailed electrical diagram of the main module; - Figure 4 is a diagram illustrating the variation of the voltage across the emitting coil of the module of Figure 3; - Figure 5 is a diagram illustrating a signal at the input of the threshold trigger circuit of the module of Figure 3; - Figure 6 is a diagram of the signal obtained at the output of the threshold trigger circuit; - Figure 7 is a diagram of an application of the device according to the invention to an electric door lock control of

motor vehicle.

  Referring to FIG. 1, an electromechanical device E is seen comprising a set of position detectors 1, 2, ... 4 for locating, by electrical information, the position of elements (not shown) on a first part P2. Each element associated with a detector can move relative to the part

P1 and / or the other elements.

  In the example considered, four detectors have been represented. It is clear that their number is not limited to this value and can be different depending on the type of application. Each detector

  includes a DI ... D4 sensor or contactor.

  A TRI ... TR4 transponder type interface is associated with each sensor. Recall that a transponder is a radio receiver-transmitter automatically responding to an external signal from, for example, a location system. In the present case, each TRi transponder interface has the role of recreating an autonomous electric power supply by induction (remote power supply) and of transmitting the information emitted by the sensor or contactor Di to a main module M, according to the technology of the

induction transponders.

  The device E comprises a second assembly for mounting on a second part P1, this second assembly comprising the main module M attached to a main connector J on which

  information may be collected.

  The main module M, an exemplary embodiment of which will be described in more detail with reference to FIG. 3, fulfills the following functions. The module M provides a remote supply of the TRi transponders by generation of an alternating magnetic field RF (at radio frequency); it collects information sent back by the transponders it converts the information received from the transponders into simple electrical signals accessible on the main connector J. For each detector i, the sensor Di and the transponder interface TRi, which is associated with it, advantageously do part of the same housing and constitute a single component. Identification means are provided at each detector i and at the main module M to allow this module to determine from which

  detector comes from information received.

  According to a first embodiment, the identification means comprise: - for each detector i an arrangement giving it a natural resonance frequency, and, for the main module M, a generator G with variable frequency suitable for supplying the transponder

associated with each sensor.

  According to a first particularly simple solution, each circuit TRi, as illustrated in FIG. 2, consists of a single resonant circuit comprising a single coil Li and a capacitor Ci in series, this circuit being tuned to the frequency specific to the detector considered. The Di sensor consists of a simple contactor mounted in the circuit and which can be closed or opened depending on the position of an element (not shown), the position of which must be identified, and which cooperates with this contactor Di. Depending on whether the resonant circuit is closed or opened by the contactor Di, the energy absorption by this resonant circuit at the resonant frequency is modified, which makes it possible to know the state of the contactor Di, and therefore the

position of the associated element.

  The transponder in Figure 2 is a passive transponder, the type used in stores to prevent theft of

articles.

  The main module M associated with this type of detector is illustrated in FIG. 3. This module M comprises a generator 5 of voltage ramp 5a, the output of which is connected to an oscillator 6 of the VCO type (oscillator with frequency adjusted by variation of voltage). One terminal of this oscillator 6 is connected to ground. The oscillator 6 provides at its output a carrier of gradually variable frequency which is sent to an input of a transconductance amplifier 7

  whose output current is proportional to the input voltage.

  The set of generator 5 and oscillator 6 constitutes the generator

G at variable frequency.

  The output of the amplifier 7 is connected to a terminal 8 of a transmitting coil 9. The other terminal of the coil 9 is directly grounded, without the intermediary of a capacitor, so that the circuit of induction either broadband. Alternatively, however, the other terminal of the coil could be connected to ground via a capacitor. By designating by L the self coefficient of the coil 9, the impedance of the coil is expressed by Lw, X corresponding to the pulsation of the current applied to the coil 9. As c depends on the frequency of the current, the impedance varies with this frequency. The voltage U at point 8 is expressed, as a function of the intensity I by the relation U = (Lo) I Thus, the voltage U increases with the frequency according to the

  ramp 5a sent by the generator 5.

  The voltage at point 8 is schematically represented in FIG. 4 where the line H constitutes the envelope of the positive voltage maxima. The point 8 is, moreover, connected to a demodulator 10 which makes it possible to recover on its output 11 only the high envelope H (fig. 4) of the voltage at point 8. The demodulator 10 comprises a diode 12

  whose anode is connected to point 8 and the cathode is connected to output 11.

  In addition, the cathode is connected in parallel by a resistor 12a and a

  capacitor 13, one terminal of which is grounded.

  The output 11 is connected to a switch 14 controlled by the oscillator 6, in such a way that it makes it possible to capture the value providing the envelope H in synchronism with the emission of the oscillator 6, always at the same moment of the carrier period. A system of this type is described in French patent application No. 97 13278 already cited. This way of operating makes it possible to smooth the value of the voltage H which, in the absence of this smoothing, would include

  relatively large ripples.

  The output of the switch is connected to a low-pass filter a comprising a resistor 15 connected in series with the output of the switch 14 and a capacitor 16 connected in bypass between the

  output 17 of the resistance and the ground.

  The output 17 is connected to the input of a circuit 18 with threshold triggering, or Schmitt flip-flop. A terminal of circuit 18 is connected to the output of the voltage ramp generator 5 so that the threshold of circuit 18 is modified to subtract the ramp and

  bring the signal flat to output 19 of circuit 18.

  The output 19 is connected to an "intelligent" circuit 20 simpler than a microcontroller (however a microcontroller may be suitable). The circuit 20 restores the elementary electrical information which is routed to the main connector J. The operation of the electromechanical device E formed by the set of detectors i (1 ... 4) and of the main module M is the

following.

  The oscillator 6 delivers a frequency ramp varying from the lowest possible frequency to the highest. The coil 9 emits an alternating magnetic field at variable frequency along the ramp

frequency.

  It will be assumed, for the explanations, that the detectors 1 ... 4 are numbered in increasing order of magnitude of their resonant frequency and, furthermore, the detectors 1, 2 and 4 are closed, then

that detector 3 is open.

  When the frequency ramp emitted by the coil 9 rises, the closed detectors 1, 2 and 4 enter into resonance when the signal received from the module M passes through the natural frequency value of the detector considered. The electrical supply created by induction in this detector makes it possible to transmit information back to the main module M. This results in an absorption peak recovered at output 11 of the demodulator 10 and reshaped at the output of the

resistance 17.

  As indicated above, the voltage signal at point 8 has an upper envelope formed by the oblique line H (fig. 4) so that the signal S (fig. 5) collected at point 17

will also be oblique.

  This signal S has three absorption peaks Ai, A2, A4 whose positions, on the frequency ramp, correspond to the natural frequencies of the closed detectors 1, 2 and 4. It should be noted that the signal at 17 is obtained by points corresponding to the closings of

switch 14.

  The oblique signal S sent to the input of circuit 18 with threshold triggering is brought back flat following a signal Sa (fig. 6) by subtraction of the ramp sent to a terminal of circuit 18. At each dip or absorption peak A1, A2, A4, circuit 18 provides a rectangular slot RI, R2, R4 whose abscissa corresponds

  at the natural frequency of one of the closed detectors.

  The output signal Sa of the circuit 18 is sent to the "intelligent" circuit 20 which can therefore identify, upon detection of each

  absorption peak Ri, R2, R4, which is the closed detector.

  The electromechanical device E of the invention therefore makes it possible, with a single main module M, to characterize the position

  as many elements as there are detectors 1, 2 ... 4.

  The transmission of information between the detectors 1 ... 4 and the module M takes place without an electrical transmission cable between the parts Pl and P2 which can therefore be movable one by

compared to each other.

  According to an alternative embodiment, the transponder interface TRi associated with each sensor is constituted by a specific integrated circuit operating in a similar manner to that of the contactless connection device described in the French patent application already cited No. 97 13278 filed on October 23, 1997. In this variant the resonant circuits LC of the transponder interfaces also have their own resonant frequency, which implies that only one transponder at a time can operate in the presence of a single frequency emitted by the main module M. Ce module M, according to this variant, is essentially similar to that of FIG. 3. However, the carrier generator G instead of delivering a frequency ramp varying from the lowest possible frequency to the highest, operates on n frequencies

  distinct, "n" being the number of detectors to be managed.

  According to another embodiment, the resonant circuits LC of the transponder interfaces all have the same resonant frequency, but an additional electronic device is added to each transponder interface TRi so that the detectors only transmit a code frame if they have previously received an address code specific to each of them. This address code is stored in the main module and is issued by this module. The address code can be constituted for example by a high rate amplitude modulation (80 to 100%) applied by the main module to the carrier which transmits it. This process is known in most of the read-write transponders used for identification, or even in

  so-called "answer on request" transponders.

  According to this embodiment, at the module M which essentially corresponds to that of FIG. 3, a logic gate or a switch is inserted between the carrier generator 6 and the amplifier 7 making it possible to generate carrier interruptions of short duration, this in order to transmit a modulation at high rate. This modulation is controlled by the "intelligent" circuit 20 responsible for reading the response frames. This circuit 20 can thus

  select the detector to be checked by an address code.

  The "intelligent" circuit 20 is in all cases part of the main module and restores the elementary electrical information which will be routed to the main connector J. When the state of all the detectors i is known, the elementary electrical information, for example " open circuit "or" closed circuit "can be reconstructed and routed to the main connector J. It may or may not be multiplexed information. The electromechanical device of the invention can be applied to the control of an electric lock V of a motor vehicle (see fig. 7). The part P2, with the detectors 1, 2, is constituted by a door of the vehicle, on which a strike B is provided, while the main module M is provided on a fixed part

  P1 of the vehicle chassis. The elements associated with detectors 1, 2 ...

  are, for example, the exterior and interior door opening handles. The electric lock V controlled by the information

  from connector J is mounted on the fixed part of the chassis.

  A variant of use of the detectors i, set out below

  afterwards, relates to all the embodiments described above, provided that the absence of response from a detector i is expected to be the observation of a defined state. In this variant, a metal mechanical part masks, or not, the detector i consisting solely of its transponder interface TRi, and not comprising a contactor. When the metal part masks the detector, it diverts the magnetic field lines which couple it to the main module. The latter can therefore recognize the information

  elementary consisting in the position of the part.

  In this case, no Di contactor or additional sensor is used. This way of proceeding can, of course, coexist with the use of the detectors mentioned above, including the

  Di contactors, in the same "wireless" detector system.

i11

Claims (10)

  1 - Electromechanical device with position detectors (1, ... 4) without electrical connections for locating, by electrical information, the position of elements on a first part (P2), this device comprising a first assembly intended to be mounted on the   first part, this first set comprising sensors (DI, ...   D4) associated with the elements to be identified, and a second assembly intended to be mounted on a second part (P1), this second assembly comprising a main module (M) attached to a main connector (J) on which the information is collected, a relative movement being possible between the two parts (P2, P1), in particular for an electric lock control of a motor vehicle, characterized by the fact: - that each sensor (DI, ... D4) is associated with an interface transponder type (TRI, ... TR4) suitable for wirelessly transmitting the information sent by the sensor (D1, ... D4) to the main module (M), - and that identification means are provided at the level of each detector (1, ... 4) and of the main module (M) to allow this module to determine from which detector a received information comes. 2 - Device according to claim 1, characterized in that the identification means of the detectors comprise: - for each detector (1, ... 4) an arrangement giving it a natural resonant frequency, - and, for the module main (M), a variable frequency generator (G; 5, 6) suitable for supplying the transponder by induction   (TRI, ... TR4) associated with each sensor.   3 - Device according to one of claims 1 or 2,   characterized by the fact that each sensor (D1, ... D4) and its associated transponder interface (TRI, ... TR4) are part of the same housing and constitute a single component.   4-Device according to one of claims 1 to 3,   characterized by the fact that the transponder (TRI, ... TR4) associated with a   sensor (D1, ... D4) is a passive transponder.   - Device according to claim 4, characterized in that the transponder (TRI, ... TR4) is constituted by a resonant circuit LC tuned to the frequency specific to the detector considered, and that the sensor (DI, ... D4) consists of a contactor mounted in the resonant circuit, which can be closed in a loop or cut depending on whether the contactor is closed or open.   6 - Device according to claim 5, characterized in that the main module (M) comprises a carrier generator (G) delivering a frequency ramp varying from the most frequent possible low to highest.   7 - Device according to claim 6, characterized in that the carrier generator (G) comprises a generator (5) of voltage ramp connected to an oscillator (6) emitting the carrier, so   to obtain a carrier with progressively variable frequency.   8 - Device according to one of claims 1 to 3,   characterized in that the transponder comprises a specific integrated circuit. 9 - Device according to claim 8, characterized in that the main module comprises a carrier generator, comprising a voltage ramp generator connected to an oscillator, which operates on a number of carrier frequencies equal to the number detectors to manage.   - Device according to one of claims 6 to 9,   characterized in that the carrier is sent to the input of a transconductance amplifier (7) whose output current is proportional to the input voltage, the output of this amplifier (7) being connected to a terminal ( 8) a transmitting coil (9), the other of which terminal is connected to ground.   1 1 - Device according to claim 10, characterized in that it comprises a demodulator (10) connected to the output terminal of the amplifier and a low-pass filter (0la) whose output is connected to   a threshold trigger circuit (18).   12 - Device according to claim 11, characterized by the   causes the connection between the output of the demodulator (10) and the pass filter   bottom (O10a) comprises a switch (14) controlled by the oscillator (6).   13 - Device according to claim 11, characterized in that the circuit (18) triggered by threshold is connected to the ramp generator (5) so that the tilt threshold is modified in connection with the ramp, so as to bring back to flat the output signal (Sa) of the circuit (18). 14 - Device according to claim 1, characterized in that all the resonant LC circuits of the transponder interfaces have the same resonant frequency, and that the identification means for each transponder include an address code stored in the main module and suitable for being selected and transmitted by this module to control a detector, and that an additional electronic device is provided in each transponder so that the transponder in question can only transmit if it has previously received the   correct address code sent by the main module.   15 - Device according to claim 14, characterized in that the address code is constituted by an amplitude modulation   at a high rate applied by the main module to the carrier it transmits.   16 - Device according to one of claims 14 or 15,   characterized in that a logic gate or a switch for generating short-term interruptions is arranged   between a carrier generator and an amplifier.