FR2891070A1 - METHOD FOR CALIBRATING AN ELECTRONIC SYSTEM INCORPORATING A BUILT-UP COMPUTING UNIT - Google Patents

Abstract

The invention relates to a method for calibrating an electronic system (1) incorporating an on-board computing unit (12) and having a connector comprising electrical supply wires (5, 6), this calibration method consisting in addressing to the calculation unit (12) of the calibration parameters consisting of a number n of digital data of predetermined values. According to the invention, this calibration method consists of electrically feeding the electronic system (1) via the power supply wires (5, 6) of said system, by controlling a modulation of one of the characteristics of said quantifiable power supply by the on-board calculation unit (12), so as to vary the said characteristic by assigning it n successive values identifiable by said on-board calculation unit as each corresponding to a digital data item to be memorized.

Description

The invention relates to a method for calibrating an electronic system

  integrating an onboard computing unit and having a connector comprising at least two power supply son.

  In the usual way, these calibration methods consist in sending, to the on-board calculation unit, calibration parameters consisting of a number n of digital data of predetermined values, and in storing said digital data in a non-volatile memory.

  As an example of an electronic system concerned by such calibration methods, mention may be made in particular in the automotive field of proximity sensors of hands-free access systems intended to be installed in the door handles so as to detecting the presence of a hand operating a handle, and controlling the initiation of an identification procedure to allow or not the unlocking of the doors of the vehicle.

  Such proximity sensors are adapted to configure themselves: E, during the first power supply conventionally performed on the assembly line of said sensors, in a calibration mode allowing a calibration unit to address their computing unit embedded calibration parameters, E is, once the calibration is carried out, in a detection mode allowing them to deliver, to a central unit on board a vehicle, a detection signal intended to initiate an identification procedure.

  In the usual way, in order to allow, on the one hand the power supply of the proximity sensor, and on the other hand the various data exchanges in one and the other modes of operation, calibration and detection, the connection of Each proximity sensor consists of: E two power supply wires, E a detection signal transmission wire, É and a wire or connection for connection to the calibration unit.

  Such a connection is however expensive to implement given the number of connections required (four in this case) and the long lengths of son required, especially to ensure the triple connection between the proximity sensor and the central unit of the vehicle.

  A first solution to simplify this connection was to use the transmission wire of the detection signal to address, in the calibration mode, the calibration parameters. This solution leads to delete a connection. On the other hand, it imposes, like the previous one, a triple wired connection between the proximity sensor and the central unit of the vehicle.

  A second solution to simplify the connection was to remove the transmission wire of the detection signal, and implement, on one of the power supply son, a measuring module adapted to measure the instantaneous consumption of the proximity sensor. According to this solution, the sensor calculation unit is, furthermore, programmed to generate a peak of consumption detectable by the measurement module during the activation of said sensor. Compared to the basic solution, such a solution leads, as the previous one, to remove a connection since it requires only two power supply connections and a calibration connection. In addition, the removed connection consists of one of the three wired links between the proximity sensor and the central unit of the vehicle.

  The present invention also aims at simplifying the connectivity of electronic systems of the type described above requiring a calibration procedure, and its essential purpose is to provide a calibration method for addressing the calibration parameters using the only son of power supply of said electronic systems.

  For this purpose, the invention provides a calibration method consisting in supplying the electronic system electrically via the power supply wires of the said system, by controlling a modulation of one of the characteristics of the said power supply that can be quantified by the embedded calculation unit, so as to vary the said characteristic by assigning it n successive values identifiable by said embedded computing unit as each corresponding to a digital data to be stored.

  The method according to the invention therefore consists of using the power supply of the electronic system as transmission vector of the calibration parameters, by modulating one of the characteristics of this power supply.

  According to this method, therefore, the only two power supply son are sufficient to ensure their own power supply function as well as the calibration function.

  In addition, these two son can also provide the transmission function of the detection signals by means, as mentioned above, the implementation of a measurement module.

  In conclusion, the method according to the invention makes it possible to reduce to two (two supply wires) the number of wires necessary for the two modes of operation of the electronic systems.

  According to a first advantageous variant of implementation of the calibration method according to the invention, modulation of the supply voltage is controlled so that said supply voltage has n successive values each corresponding to a digital data item to be stored.

  According to a second advantageous variant of implementation of the calibration method according to the invention, there are n interruptions of the power supply determining n successive periods of actual power supply, and a modulation is controlled consisting in assigning a predetermined duration to each feeding periods.

  In addition, according to this second variant, an on-board computing unit with an internal clock is advantageously used, and the duration of each supply period is measured by means of said internal clock.

  Moreover, advantageously according to the invention: a variable known as a calibration state is stored at which an initial value representative of a non-calibrated raw state of the on-board calculation unit is initially assigned, and to which the said calculation unit is programmed to assign an incremented value conferred on said variable once a calibration procedure has been completed, É at each start of the electronic system, the on-board calculation unit is programmed to check the value of the variable of calibration state in order to control either the launch of a calibration procedure or the start of the normal operating procedure of said electronic system.

  This specification makes it possible to automatically switch the electronic system either in its calibration mode if it has not been performed, or in its detection mode once said system is calibrated.

  In addition, the on-board calculation unit is advantageously programmed to reassign its initial value to the calibration state variable, and thus to wait for a calibration procedure, during a power supply having specific characteristics.

  Thus the method of the invention offers the faculty, if necessary, to renew the calibration procedure of electronic systems.

  Other features, objects and advantages of the invention will emerge from the detailed description which follows with reference to the accompanying drawing which represents by way of non-limiting example a preferred embodiment: - Figure 1 shows schematically a vehicle equipped with a hands-free access system comprising a proximity sensor according to the invention; FIG. 2 represents a view of a sensor according to the invention.

  The electronic system represented in FIG. 1 to which the calibration method according to the invention applies consists of a proximity sensor 1 of a hands-free access system.

  Such a proximity sensor 1 is adapted, as shown in Figure 1, to be integrated inside the handle 2 of one of the doors of the vehicle 3 equipped with the hands-free access system, so as to detect the presence of a hand actuating the handle 2, and to control the triggering of an identification procedure to allow or not the unlocking of the doors of the vehicle 3.

  In addition, and in a usual manner, this proximity sensor 1 is connected to a central unit 4 embedded in the vehicle 3, from which the power supply of said proximity sensor is ensured, and to which the signaling signals are transmitted. detection delivered by the proximity sensor 1, intended to initiate an identification procedure.

  For this purpose, the connection between each proximity sensor 1 and the central unit 4 consists of two electrical wires 5, 6, on the one hand ensuring the power supply of the proximity sensor 1, and on the other hand on a of which (power wire 5 in FIG. 1) is implanted a measurement module 7 adapted to measure the instantaneous consumption of the proximity sensor 1.

  The proximity sensor 1 itself comprises, as illustrated in FIG. 2, an electrode 11 forming the detection element determining the sensitive surface of said sensor, connected at one of its longitudinal ends to a printed circuit 10 integrating a microcontroller 12 comprising in particular a computing unit 13, an internal clock 14 and a non-volatile memory 15.

  During its normal operation, such a proximity sensor 1 is adapted to be configured in a detection mode in which the microcontroller 12 is programmed to generate a consumption peak detectable by the measurement module 7, and representative, for the unit central 4 embedded in the vehicle 3, a bias of the sensing element formed by the electrode 11.

  In a preliminary phase, generally carried out directly on the assembly line, the proximity sensors 1 are adapted to configure themselves in a calibration mode which makes it possible, during their first power supply, for a calibration unit to address calibration parameters to the microcontroller 12.

  In the first place, the start of the calibration procedure is conditioned, during the electrical connection, to the identification of a predetermined value representative of a non-calibrated raw state assigned to a stored variable of calibration status.

  According to the invention, this calibration procedure consists in electrically feeding the proximity sensor 1 by connecting the supply wires 5, 6 to a calibration unit adapted to control, for n calibration parameters to be memorized: power supply determining n successive periods of actual power supply, É a modulation consisting in assigning a predetermined duration to each of the power periods.

  Thus, for example, if the calibration parameters are stored as binary data 0 or 1, the modulation consists in assigning a duration t1 or a duration t2 to each supply period.

  In addition, the duration of each power supply period is measured by customarily using the internal clock 14 of the microcontroller 12, and the binary data are successively stored in the non-volatile memory 15 as the procedure unfolds. calibration.

  Finally, once the calibration procedure is completed, that is, once the n digital data has been stored, an incremented value is assigned to the calibration status variable, so that during subsequent connections of the proximity sensor 1, the latter is configured directly in its detection mode.

  It should be noted, however, that it is possible, if necessary, according to the invention, to reassign its initial value to the calibration state variable, and thus to wait for a calibration procedure. For this purpose, it is simply necessary to program a reset procedure consisting in controlling a power supply having specific characteristics.

  In conclusion, according to the invention, a connection consisting of two single power supply wires 5, 6 is required to ensure the operation (power supply, calibration procedure (s), transmission of the detection signals) of an electronic system such as a proximity sensor 1.

Claims (1)

CLAIMS,   1. A method of calibrating an electronic system (1) incorporating an on-board calculation unit (12) and having a connector comprising electrical supply wires (5, 6), this calibration method consisting in addressing to the unit for calculating (12) calibration parameters consisting of a number n of digital data of predetermined values, and storing said digital data in a non-volatile memory (15), said calibration method being characterized in that it is to electrically power the electronic system (1) via the power supply son (5, 6) of said system, by controlling a modulation of one of the characteristics of said quantifiable power supply by the onboard computing unit (12), so as to vary the said characteristic by assigning it n successive values identifiable by said onboard calculation unit as each corresponding to a given digital to memorize.   2l calibration method according to claim 1 characterized in that one controls a modulation of the supply voltage so that said supply voltage has n successive values each corresponding to a digital data to be stored.   3 / A calibration method according to claim 1 characterized in that one n interrupts the power supply determining n successive periods of actual power supply, and in that one controls a modulation consisting in assigning a predetermined duration at each feeding period.   4 / Calibration method according to claim 3 characterized in that an on-board calculation unit (12) is used with an internal clock (15), and in that the duration of each period of time is measured. power supply by means of said internal clock.   5 / Calibration method according to one of the preceding claims characterized in that: E is stored a so-called calibration state variable to which is initially assigned an initial value representative of a non-calibrated raw state of the calculation unit on board (12), and to which said calculation unit is programmed to assign an incremented value conferred on said variable once a calibration procedure has been completed, É at each start of the electronic system (1), the calculation unit board (12) is programmed to check the value of the calibration state variable to control either the initiation of a calibration procedure or the start of the normal operating procedure of said electronic system.   6 / calibration method according to claim 5 characterized in that the on-board calculation unit (12) is programmed to reassign its initial value to the calibration state variable, and thus to wait for a procedure of calibration, during a power supply with specific characteristics.