FR3082075A1 - COMMUNICATION DEVICE, CAPACITIVE DETECTION DEVICE AND EQUIPMENT PROVIDED WITH SUCH A DETECTION DEVICE - Google Patents

Abstract

The present invention relates to a communication device (200) intended to be implemented with a communication bus in differential mode comprising at least two differential lines (102,104) for conveying a first signal (110) in differential mode between at least two modules differential communication (1061,1062), characterized in that it further comprises: -at least one transmitter (202) in common mode, for injecting the same second signal (210), said in common mode, alternating, on each said at least two differential lines (102,104), at a point on said communication bus; and at least one receiver (206) in common mode, for receiving said second signal (210), at another point of said communication bus.

Description

"Communication device, capacitive detection device and equipment provided with such a detection device"

Technical area

The present invention relates to a signal communication device using a communication bus in differential mode. It also relates to a capacitive detection device provided with such a communication device, and to equipment equipped with such a capacitive detection device.

The field of the invention is, without limitation, that of communication buses in differential mode, in particular for capacitive detection devices, and more particularly in the field of robotics.

State of the art

Industrial or domestic robots, in particular cobots, generally comprise a body on which a functional head is fixed, in the form of a tool or a tool holder, allowing them to accomplish one or more tasks in an environment. These robots are generally equipped with a communication bus in differential mode allowing the various organs of the robot to communicate with each other.

To be able to use a robot in an environment comprising humans and / or objects, said robot can be equipped with capacitive detection units for detecting said humans / objects.

In known manner, each capacitive detection unit comprises measurement electrodes, possibly guard electrodes, polarized at an alternating excitation potential and detection electronics. The electrodes of a detection unit can be integrated into a covering element, or shell, replacing, or in addition to, an existing covering element of the robot.

To avoid parasitic coupling capacities between the different detection units fitted to a robot, it is necessary that the electrodes

- 2 these units are polarized at the same excitation potential. This requirement requires signal transmission lines between the various capacitive detection units, which makes the integration of these units on robots, in particular existing robot arms, time consuming, expensive and cumbersome.

In general, the problem described above arises in any equipment implementing several functional units to be supplied by the same supply or synchronization signal.

An object of the present invention is to remedy the aforementioned drawbacks.

Another object of the present invention is to provide a signal communication device allowing a simpler, less expensive and less time-consuming integration of functional units, in particular capacitive detection units, in an equipment, and in particular in a robot such as a robotic arm.

Statement of the invention

At least one of these aims is achieved with a communication device intended to be implemented with a communication bus in differential mode comprising at least two differential lines for conveying a first signal in differential mode between at least two differential communication modules, characterized in that it further comprises:

at least one transmitter in common mode, for injecting the same second signal, said in common mode, alternating, on each of said at least two differential lines, at a point of said communication bus; and

at least one receiver in common mode, to receive said second signal, at another point of said communication bus.

Thus, the communication device according to the invention makes it possible to use a communication bus in differential mode, existing within equipment such as a robot, for conveying, in common mode, a synchronization or excitation signal. , to several functional units within said equipment.

- 3 Consequently, when several functional units need to be synchronized, or supplied by the same excitation signal, such as capacitive detection units, the communication device according to the invention makes it possible to integrate these units. functional within said equipment without drawing additional transmission lines dedicated to excitation or synchronization of these functional units: which makes the integration of these units simpler, less expensive and less time-consuming.

Similarly, the communication device according to the invention makes it possible to use a communication bus in differential mode, existing within equipment such as a robot, to convey, in common mode, an additional digital communication signal or analog, to, or from, or between, several functional units within said equipment.

In the present description, to avoid red tape, the term “ground potential” designates a reference potential of the electronics, which can for example be an electrical ground or a ground potential. This ground potential can correspond to a ground potential, or to another potential connected or not to the ground potential.

In the present application, two alternative potentials are identical at a given frequency when they each comprise an alternative component identical to this frequency. Thus, at least one of the two potentials identical to said frequency may further comprise a DC component, and / or an AC component of frequency different from said given frequency.

Similarly, two alternative potentials are different at the working frequency when they do not include an alternative component identical to this working frequency.

The second alternating signal can preferably be a sinusoidal signal.

Alternatively, the second alternating signal can be a square, triangular, or any other waveform signal. It can also be a communication signal with information coded in digital or analog form.

- 4 According to embodiments, at least one transmitter in common mode, and / or at least one receiver in common mode, can comprise a block, called differential mode isolation, with a connection to each differential line and a connection , called common mode, having an impedance for the signal in common mode, between the connections to the differential lines and the common mode connection, less than an impedance for the signal in differential mode, between said connections to the differential lines.

The impedance for the common mode signal can be defined as the ratio, or the modulus of the ratio, between the common mode voltage (or the instantaneous average voltage) between the differential lines and the common mode connection, and the total current or the sum of the currents flowing between the differential lines and the common mode connection.

The impedance for the signal in differential mode can be defined as the ratio, or the modulus of the ratio, between the voltage between the differential lines, and the current flowing between the differential lines via the isolation block of the differential mode.

According to embodiments:

- the impedance for the signal in common mode can be equal to or less than half, or a quarter, or a tenth, of the impedance for the signal in differential mode, at least in a frequency range;

- the impedance for the signal in common mode can be zero, or lower by one or more orders of magnitude, than the impedance for the signal in differential mode, at least in a frequency range.

This differential mode isolation block thus allows the injection or collection of a common mode voltage on the differential lines while avoiding short-circuiting the differential lines to the electrical ground or between them for the differential signal.

When the differential mode isolation block is implemented in a common mode transmitter, the common mode signal can be injected through the common mode connection. This common mode signal can be by

- 5 example generated by an oscillator of the common mode transmitter connected to this common mode connection.

When the differential mode isolation block is implemented in a common mode receiver, the common mode signal can be collected at the common mode connection.

According to one embodiment, the differential mode isolation block can comprise inductors, called differential mode isolation, electromagnetically coupled in opposite directions and arranged to be connected respectively to a differential line on the one hand and to the connection in common mode on the other hand.

Each insulation choke can be a coil.

Since the differential mode insulation chokes are in the opposite direction, the current due to the voltage across one of the chokes induces a voltage of opposite polarity or direction across the other of the chokes.

The differential mode isolation block may include a ferromagnetic core around which the differential mode isolation inductors are wound in opposite winding directions, or connected in opposite directions or polarities, so as to achieve electromagnetic coupling between said insulation chokes.

Such a ferromagnetic core is a simple and inexpensive means of achieving effective electromagnetic coupling between the insulation coils.

According to embodiments, the differential mode isolation block can comprise resistors, called differential mode isolation resistors, arranged to be connected respectively to a differential line on the one hand and to the common mode connection on the other hand. go.

According to one embodiment, at least one transmitter in common mode may comprise a circuit of the feedback amplifier type, of which:

- The output is connected in parallel to the insulation resistors of the differential mode, arranged to be connected respectively to said at least two differential lines; and

- An input is connected in parallel to resistors, called feedback, arranged to be connected respectively to said at least two differential lines.

The insulation resistances of the differential mode make it possible, as explained above, to avoid short-circuiting the differential lines to the electrical ground.

The feedback resistors make it possible to measure the common mode voltage injected on the differential lines, so as to be able to compensate for the voltage drops in said insulation resistors of the differential mode.

The insulation resistances of the differential mode can preferably be of identical value.

The parallel feedback resistors can preferably be of identical value.

The feedback amplifier type circuit may include an operational amplifier.

The common mode transmitter may further include an oscillator delivering the common mode signal to be injected into the differential lines.

In this embodiment, this oscillator can be connected to an input of the feedback amplifier type circuit, or of the operational amplifier.

According to one embodiment, at least one receiver in common mode may comprise a circuit of the feedback amplifier type mounted as a voltage summator, and of which:

- An input is connected in parallel to the insulation resistors of the differential mode, arranged to be connected respectively to said at least two differential lines; and

- The output is connected to said input by at least one feedback resistance.

This circuit can include an operational amplifier.

It performs a summation of the voltages present on the differential lines, which makes it possible to cancel the signal in differential mode so as to keep only the signal in common mode.

- 7 The differential mode insulation resistors make it possible to avoid short-circuiting the differential lines to the electrical ground, with regard to the differential signal.

The insulation resistances of the differential mode can preferably be of identical value.

The device according to the invention may comprise, for at least one differential communication module, a common mode isolation block with connections to the differential lines and connections, called differential mode, to the communication module, having a impedance for the signal in common mode, between the connections to the differential lines and the connections to the differential communication module, greater than an impedance for the signal in differential mode, between the connections to the differential lines.

The impedance for the common mode signal can be defined as the ratio, or the ratio module, between the common mode voltage (or the instantaneous average voltage) between the differential lines and the differential communication module, and the total current or the sum of the currents flowing between the differential lines and the differential communication module, in particular when this differential communication module has an impedance to low ground (operation as a differential transmitter).

The impedance for the signal in differential mode can be defined as the ratio, or the modulus of the ratio, between the voltage between the differential lines, and the current flowing between the differential lines via the common mode isolation block.

According to embodiments:

- the impedance for the signal in common mode can be equal to or greater than double, or four times, or ten times, the impedance for the signal in differential mode, at least in a frequency range;

- the impedance for the signal in differential mode can be zero, or lower by one or more orders of magnitude, than the impedance for the signal in common mode, at least in a frequency range.

- 8 Thus, the common mode isolation block makes it possible to inject, respectively to receive, the signal in differential mode, while blocking the signal in common mode, and without disturbing the operation of the common mode.

According to an exemplary embodiment, the common mode isolation block may include inductors, called common mode isolation, intended to be placed respectively in series between the differential lines and the differential communication module, said isolation inductors of the common mode being coupled to each other electromagnetically in an identical sense, or polarity.

Since the common mode isolation inductors are in the same direction, the current due to the voltage across one of the inductors induces a voltage of the same polarity or in the same direction across the other of the inductors.

In particular, the common mode isolation block can advantageously include a ferromagnetic core around which the common mode isolation inductors are wound in identical winding directions, or connected in identical directions, so as to achieve electromagnetic coupling between said insulation chokes.

Advantageously, the device according to the invention can comprise, for at least one differential communication module, a module for connecting said differential communication module to the differential lines.

The connection module can include the common mode isolation block, and:

- a first connection interface with differential lines; and

- A second interface for connection with the differential communication module, connected to said first interface downstream of the isolation block of the common mode, seen from said first interface.

Such a connection module thus enables a simple and rapid connection of a differential communication module to the differential lines, by being inserted between said communication module.

- 9 differential and differential lines, like an adapter or connector.

Above all, such a connection module makes it possible to use existing differential communication modules, without having to intervene on said differential communication modules.

The connection module may further comprise a third interface for connection to a common mode transmitter, respectively to a common mode receiver, connected to the first interface upstream of the common mode isolation block, seen from said first interface.

Thus, the connection module makes it possible to connect, through the same interface with the differential lines, both the differential communication module and the transmitter in common mode, respectively the receiver in common mode.

In general, the invention can include the various elements which make it possible to convey a signal in common mode on an existing differential line, by being inserted on this line by using existing connectors, without disturbing the operation of this differential line from the point view of differential communication.

The communication device may not include the communication bus in differential mode, respectively the differential communication module (s), the latter may be already present within a device. in which said communication device is implemented.

Alternatively, the communication device according to the invention can also comprise:

- a communication bus in differential mode with at least two differential lines; and

- at least one communication module in differential mode.

The communication device according to the invention can be implemented in any type of equipment for conveying an excitation signal, or a signal

- 10 synchronization, to functional units designed to perform a given function, such as measurement, detection, signaling, etc.

According to an advantageous application, the communication device according to the invention can be implemented in a capacitive detection device comprising several capacitive detection units.

According to another aspect of the same invention, there is provided a device for capacitive detection of an object, comprising at least capacitive detection unit.

Each capacitive detection unit can include:

- at least one measuring electrode, and

- Detection electronics for biasing each measurement electrode to an alternating potential, called an excitation potential, different from a ground potential, and measuring a signal relating to the electrode-object capacity between each measurement electrode and said object.

Advantageously, the capacitive detection device according to the invention can also comprise a communication device according to the invention:

- in which, the second signal injected in common mode by the transmitter in common mode is used to generate the excitation signal, respectively synchronization signal, by each detection unit; and

- comprising a common mode receiver of said second common mode signal for each detection unit.

Thus, the capacitive detection device makes it possible to use a communication bus in differential mode for synchronization, and / or excitation, of several capacitive detection units.

As specified above, the communication bus in differential mode can be a bus already present within an item of equipment and used for communication between the various members of said item of equipment. Consequently, it is not necessary to provide a first bus dedicated to communication in differential mode and a second bus dedicated to synchronizing the communication units.

- 11 capacitive detection, the two functions being implemented with a single communication bus in differential mode.

Furthermore, according to a particularly advantageous characteristic, a communication module in differential mode can be associated with each capacitive detection unit, for:

- send a detection signal supplied by said capacitive detection unit, and / or

- receiving a configuration and / or control signal from said capacitive detection unit;

as the first signal transmitted, respectively received, in differential mode.

In addition, at least one capacitive detection unit can also comprise at least one guard electrode polarized at a guard potential, identical or substantially identical to the excitation potential, generated using the second signal.

The guard may be common to at least two, in particular all, the measurement electrodes of said detection unit.

At least one guard electrode can be individual to a single measurement electrode.

According to yet another aspect of the same invention, there is provided equipment provided with a capacitive detection device according to the invention.

According to embodiments of the equipment according to the invention:

- the detection units can be linked to said equipment, and

the communication bus in differential mode can advantageously be a communication bus used in said equipment between different members of said equipment.

In addition, the communication modules in differential mode can be modules present in said equipment with the communication bus in differential mode.

- 12 The equipment can be, for example, in the form of a fixed or mobile robot, of humanoid or other form, or in the form of a robotic manipulator arm, or of a robot arm or of a segment robot, or an autonomous vehicle (AGV).

According to embodiments, the detection device can be integrated into an element of the equipment, such as a shell or a cover.

Alternatively, the detection device can be independent of a member of the equipment and be arranged in / on a member of said equipment in a removable or removable manner.

Description of the figures and embodiments

Other advantages and characteristics will appear on examining the detailed description of nonlimiting examples, and the appended drawings in which:

- FIGURE 1 is a schematic representation of an exemplary embodiment of a communication device in differential mode, according to the state of the art;

- FIGURE 2 is a schematic representation of a first embodiment of a communication device according to the invention;

- FIGURE 3 is a schematic representation of a second embodiment of a communication device according to the invention;

- FIGURE 4 is a schematic representation of a nonlimiting exemplary embodiment of an isolation block of the differential mode which can be implemented in a communication device according to the invention;

- FIGURE 5a is a schematic representation of a nonlimiting exemplary embodiment of a common mode transmitter that can be implemented in a communication device according to the invention;

- FIGURE 5b is a schematic representation of a nonlimiting exemplary embodiment of a common mode receiver which can

- 13 be implemented in a communication device according to the invention;

- FIGURE 6 is a schematic representation of a nonlimiting exemplary embodiment of a differential mode isolation block that can be implemented in a communication device according to the invention;

- FIGURE 7 is a schematic representation of a non-limiting exemplary embodiment of a common-mode isolation block that can be implemented in a communication device according to the invention;

- FIGURE 8 is a schematic representation of an example of a non-limiting embodiment of signals conveyed in a communication device according to the invention;

- FIGURE 9 is a schematic representation of a first non-limiting embodiment of a capacitive detection device according to the invention;

- FIGURE 10 is a schematic representation of a second non-limiting embodiment of a capacitive detection device according to the invention; and

FIGURE 11 a schematic representation of a nonlimiting exemplary embodiment of a robot implementing a capacitive detection device according to the invention.

It is understood that the embodiments which will be described below are in no way limiting. It is possible in particular to imagine variants of the invention comprising only a selection of characteristics described hereinafter isolated from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from the prior art. This selection comprises at least one preferably functional characteristic without structural details, or with only a part of the structural details if this part only is sufficient to confer a technical advantage or to differentiate the invention from the state of the prior art.

- 14 In particular, all the variants and all the embodiments described can be combined with one another if there is nothing technically opposed to this combination.

In the figures, the elements common to several figures keep the same reference.

FIGURE 1 is a schematic representation of an example of a communication bus in differential mode.

The bus 100, shown in FIGURE 1, includes two differential communication lines 102 and 104, for example forming a differential pair, a line carrying the supply potential denoted V and an electrical ground line GND.

The communication bus in differential mode 100 connects two communication modules 106i-106 ₂ in differential mode. Each of the communication modules 106 can transmit, respectively receive, a first communication signal in differential mode to, respectively from, the other of the communication modules 106. To do this, each of the modules 106i and 106 ₂ can be selectively transmitter or receiver . In FIGURE 1, the module 106i is a transmitter and the module 106 ₂ is a receiver and receives the first signal materialized by the arrow 110.

In general, each of the modules 106i and 106 ₂ can be either only transmitter or receiver, or configurable as transmitter and receiver.

In FIGURE 1, only two differential lines are shown so as not to weigh down FIGURE 1. Of course, the power bus 100 can comprise more than two differential lines.

Likewise, in FIGURE 1, only two differential modules 106 are shown so as not to weigh down FIGURE 1. Of course, the communication bus 100 can be associated with more than two differential modules 106.

The communication bus 100 can operate for example according to the EIA-485 or RS-485 standard. More generally, it can comply with any other serial communication standard, 2-wire (half duplex), 4-wire (full duplex), etc., allowing the transfer of digital signals in differential mode, and in general any standard. differential transmission capable of withstanding

- 15 common mode voltage sufficient to cover the amplitude of the signals to be transmitted and the operating margin. We can also cite CAN type buses, and in general all physical layers on twisted differential Ethernet type (Ethercat, Profinet, etc.).

FIGURE 2 is a schematic representation of a first embodiment of a communication device which can be implemented with the bus 100 of FIGURE 1.

The device 200, shown in FIGURE 2, includes all the elements of the device 100 in FIGURE 1.

The device 200 further comprises a transmitter 202 in common mode for transmitting a second signal in common mode on the differential lines 102 and 104. The second signal in common mode is an alternating signal, in particular sinusoidal.

The common mode transmitter 202 comprises a block 204 for isolating the differential transmitter mode, through which it is connected to each of the two differential lines 102 and 104. In general, this differential mode isolation block d transmitter 204 allows the second signal to be injected in common mode on the differential lines 102 and 104 without disturbing the first signal in differential mode. For this, he must present:

a low impedance for the common mode signal, that is to say the second signal, so as not to excessively weaken this signal; and

a high impedance, or at least higher than the impedance for the signal in common mode, for the signal in differential mode, that is to say the first signal exchanged between the differential communication modules 106. It must also have a sufficiently high impedance between each differential line 102, 104 and the GND ground in all circumstances so as not to short-circuit these lines.

Thus, the common mode transmitter 202 can inject a common mode signal on the differential lines 102 and 104 without short-circuiting or excessively disturbing the differential mode.

The device 200 also comprises a receiver 206 in common mode for receiving the signal in common mode transmitted by the transmitter in common mode 202, and conveyed by the differential lines 102 and 104.

Like the common mode transmitter 202, the common mode receiver 206 includes a block 208 for isolating the receiver differential mode, through which it is connected to each of the two differential lines 102 and 104. generally, this receiver differential isolation block 208 makes it possible to collect the second signal in common mode on the differential lines 102 and 104 without disturbing the first signal in differential mode. For this, as before, he must present:

a low impedance for the common mode signal, that is to say the second signal, so as not to excessively weaken this signal; and

a high impedance, or at least higher than the impedance for the signal in common mode, for the signal in differential mode, that is to say the first signal exchanged between the differential communication modules 106. It must also have a sufficiently high impedance between each differential line 102, 104 and the GND ground in all circumstances so as not to short-circuit these lines.

Thus, the common mode receiver 206 can receive the common mode signal, materialized by the arrow 210, from the differential lines 102 and 104 without short-circuiting or excessively disturbing the differential mode.

The common mode receiver 206 may include one or more optional functional units 212 using the common mode signal 210.

Alternatively, or in addition, the common mode signal can be supplied to at least one unit 214, external to the common mode receiver 206.

To avoid disturbing the differential modules 106 by the common mode signal 210, the device 200 comprises for each differential module 106i-106 ₂ , a common mode isolation block, respectively 216i and 216 ₂ , inserted between said differential module and differential lines

- 17 102-104. Thus, the differential module 106i is connected to the differential lines

102-104 through the common mode isolation block 216i and the differential module 106 ₂ is connected to the differential lines 102-104 through the common mode isolation block 216 ₂ .

Each common mode isolation block 216 has the same function, namely, for each differential line 102-104, to maintain its high impedance relative to the GND mass in common mode, without significantly changing its impedance in differential mode.

FIGURE 3 is a schematic representation of a second embodiment of a communication device according to the invention.

The device 300, of FIGURE 3, includes all the elements of the device 200 of FIGURE 2.

The device 300 comprises, in addition, a connection module 302 in which is integrated the common mode isolation block 216 ₂ associated with the differential module 106 ₂ .

In addition, unlike the device 200 of FIGURE 2, in the device 300 of FIGURE 3, the connection of the differential lines 102 and 104 with on the one hand the differential module 106 ₂ , and on the other hand the receiver in common mode 206, is carried out through the connection module 302.

To do this, the connection module 302 includes:

- A first interface 304 for connection with the differential lines 102 and 104;

- A second link interface 306 with the differential module IO62: this second interface 306 is connected to the first interface 304 through the common mode isolation block 216 ₂ ; and

a third link interface 308 with the common mode receiver 206: this third interface 308 is connected to the first interface 304 upstream of the common mode isolation block 216 ₂ integrated in the connection module 302.

The connection module 302 has the advantage of being able to connect, with a single interface to the differential lines 102-104, both the common mode receiver 206 and the differential module 106 _{2 to} said lines

- 18 differentials 102-104, which is simpler, faster, and more ergonomic.

Of course, although not shown in FIGURE 3, it is possible to provide a similar connection module for connecting the common mode transmitter 202 and the differential module 106i to the differential lines 102 and 104, and comprising the isolation block common mode 216i.

FIGURE 4 is a schematic representation of a nonlimiting exemplary embodiment of a differential mode isolation block that can be implemented in a communication device according to the invention.

The differential mode isolation block 400, shown in FIGURE 4, may be the transmitter differential mode isolation block 204 of the common mode transmitter 202 of FIGURES 2, 3 and 5a, or the d block isolation of the receiver differential mode 208 from the common mode receiver 206 of FIGURES 2, 3 and 5b.

In other words, the differential mode isolation block 400 of FIGURE 4 can be used in the common mode transmitter 202 or in the common mode receiver 206.

The differential mode isolation block 400 includes a first isolation resistance 402 connected to the differential line 102, and a second isolation resistance 404 connected to the differential line 104. These isolation resistors 402 and 404 are connected between they according to their other terminal to a connection, called common mode, 406.

Under these conditions, the impedance Z _diff between the differential lines 102 and 104, as "seen" by the signal in differential mode corresponds to 2R, with R, the value of the insulation resistances, while the impedance Z _C m such that "view" by the signal in common mode corresponds to the insulation resistances in parallel, ie Ri / 2. There is thus an impedance for the signal in common mode lower, by a factor of 4, than the impedance for the signal in differential mode. Furthermore, even if the common mode connection 406 is connected to ground GND (for example by means of a signal source in common mode), the impedance between each differential line 102, 104 and the ground GND corresponds at least the value of an insulation resistance R ,,

- 19 therefore greater than the impedance Z _C m as "seen" by the signal in common mode.

In the common mode transmitter 202, a common mode signal is injected at the common terminals of the insulation resistors 402 and 404, for example by a voltage source or an oscillator. This signal in common mode is thus coupled on the differential lines 102 and 104 with a minimum voltage drop across the insulation resistors 402, 404. Conversely, in the common mode receiver 206, we obtain at the common terminals common mode 406 of the insulation resistors 402 and 404 a signal corresponding to the common mode of the voltages on the differential lines 102 and 104. This signal corresponding to the common mode can be detected by any circuit, for example of amplifier type.

FIGURE 5a is a schematic representation of a nonlimiting exemplary embodiment of a common mode transmitter that can be implemented in a communication device according to the invention.

The common mode transmitter 202, shown in FIGURE 5a, may be the common mode transmitter 202 of FIGURES 2 and 3.

The common mode transmitter 202 includes the differential mode isolation block 400, and an oscillator 502 providing the common mode signal to be injected into the differential lines 102 and 104.

The common mode transmitter 202 comprises a circuit producing an operational amplifier 504, the non-inverting input “+” of which is connected to the oscillator 502.

The output of the operational amplifier 504 is connected to each of differential lines 102 and 104, by means of insulation resistors 402, 404 forming an isolation block of differential mode 400 as described above.

The inverting input “-” of the operational amplifier 504 is connected to each of the differential lines 102 and 104, by a feedback resistance R _m . The purpose of the resistors R _{m is} to measure the common mode voltage injected into the differential lines 102 and 104 to compensate for the voltage drops in the insulation resistors 402, 404.

- 20 According to an alternative embodiment (not shown), the operational amplifier 504 could comprise only a feedback resistance R _m connecting its inverting input “-” and its output, according to a conventional feedback assembly. .

FIGURE 5b is a schematic representation of a nonlimiting exemplary embodiment of a common mode receiver that can be implemented in a communication device according to the invention.

The common mode receiver 206, shown in FIGURE 5, may be the common mode receiver 206 of FIGURES 2 and 3.

The common mode receiver 206 includes the differential mode isolation block 400.

The receiver 206 further comprises an operational amplifier 506 with feedback, connected according to its inverting input “-” to the insulation resistors 402, 404 of the isolation block of the differential mode 400. The non-inverting input “+” of the operational amplifier 506 is connected to GND ground.

The output of the operational amplifier 506 is looped back to its inverting input “-” by a feedback resistance R _f .

Under these conditions, the output of the operational amplifier 506 provides a summation of the voltages on the differential lines 102 and 104, and therefore the signal in common mode 210, with an amplitude which is a function of the values of the resistances (or impedances) R , and R _f .

FIGURE 6 is a schematic representation of a nonlimiting exemplary embodiment of a differential mode isolation block that can be implemented in a communication device according to the invention.

The differential mode isolation block 600, shown in FIGURE 6, can be the differential mode isolation block 204 of the common mode transmitter 202 of FIGURES 2-3, or the differential mode isolation block 208 of the common mode receiver 206 of FIGURES 2-3.

In other words, the differential mode isolation block 600 of FIGURE 6 can be used in the common mode transmitter 202 or in the common mode receiver 206.

Furthermore, the differential mode isolation block 600 can be used in place of the differential mode isolation block 400 as illustrated in FIGURES 5a-5b.

The differential mode isolation block 600 comprises a first inductor 602, for example formed by a coil, connected to the differential line 102, and a second inductor 604, for example formed by a coil, connected to the differential line 104. These inductors 602 and 604 are connected together according to their other terminal, corresponding to a so-called common mode connection 608.

The inductors 602 and 604 are electromagnetically coupled in opposite directions. In particular, the differential mode isolation block 600 comprises a ferromagnetic core 606 around which the inductors 602 and 604 are wound in opposite winding directions, or wound in identical winding directions and connected in opposite directions or polarities .

Under these conditions, a voltage applied to the terminals of an inductor generates a voltage of opposite direction in the coupled inductor, by mutual inductance effect. It follows that, assuming a perfect electromagnetic coupling between inductors 602 and 604 of value L:

the impedance Z _diff between the differential lines 102 and 104, as "seen" by the signal in differential mode, is equal to 4Lœ (ω being the pulsation), ie a high value. Furthermore, the impedance between a differential line 102, 104 and the GND ground, in the event of a short-circuit of the common mode connection 608, is at least equal to Lœ, that is also a high value;

the impedance Z _C m, between the differential lines 102 and 104 on the one hand and the ground GND on the other hand, as "seen" by the signal in common mode, is zero or almost zero.

Thus, in the common mode transmitter 202, a common mode signal (for example from an oscillator) injected at the common terminals of the inductors 602 and 604 is thus coupled to the differential lines 102 and 104 almost without losses. Conversely, in the common mode receiver 206, a signal corresponding to the common mode of the voltages on the differential lines 102 is obtained at the common terminals of the inductors 602 and 604.

- 22 and 104. The signal in differential mode is also not significantly disturbed.

FIGURE 7 is a schematic representation of a nonlimiting exemplary embodiment of a common mode isolation block that can be implemented in a communication device according to the invention.

The common mode isolation block 700, shown in FIGURE 7, can be the common mode isolation block 216i of the differential module 106i, or the common mode isolation block 216 ₂ of the differential module 106 ₂ of FIGURES 2-3.

The common mode isolation block 700 comprises a first inductor 702, for example formed by a coil, connected to the differential line 102, and a second inductor 704, for example formed by a coil, connected to the differential line 104.

The inductors 702 and 704 are connected at the output respectively to each differential input and / or output of the differential communication modules (106i, 106 ₂ ).

Inductors 702 and 704 are electromagnetically coupled in identical directions or polarities. In particular, the insulation block 700 comprises a ferromagnetic core 706 around which the inductors 702 and 704 are wound in identical winding directions, and of course connected in identical directions.

Under these conditions, a voltage applied to the terminals of an inductor generates a voltage of the same direction in the coupled inductor, by mutual inductance effect. It follows that, assuming a perfect electromagnetic coupling between inductances 702 and 704 of value L:

the impedance Z _diff between the differential lines 102 and 104 due to the inductors 702 and 704, as "seen" by the signal in differential mode, is very low, or even zero;

the impedance Z _C m for each inductance, between the differential lines

102 and 104 on the one hand and GND ground on the other hand, as "seen" by the signal in common mode, remains high, of the order of Lo, whatever the state (transmitter or receiver) of the module differential communication 106 to which the inductors 702, 704 are connected.

- 23 Thus, on the one hand the transmission of the differential signal in the differential module is not significantly disturbed, and on the other hand the state of the differential module (in transmitter or in receiver) does not significantly affect the signal in common mode.

FIGURE 8 is a schematic representation of an example of a signal conveyed by the differential lines, by superimposition of the signal in differential mode and of the signal in common mode.

FIGURE 8 shows the common mode signal 210, initially injected into each differential line 102 and 104.

Line 802 shows the signal carried by the differential line 102, obtained by adding the signal in common mode 210 to the signal in differential mode.

Line 804 shows the signal carried by the differential line 104, obtained by adding the signal in common mode 210 to the signal in differential mode.

Thus, it seems clear that by averaging or summing the signals conveyed by the differential lines 102 and 104, the signal in common mode 210 is found.

In addition, the signal carried by each differential line has a peak voltage between + 7V and -7V, which is compatible with the communication bus in differential mode.

FIGURE 9 is a schematic representation of a first non-limiting exemplary embodiment of a capacitive detection device.

The capacitive detection device 900, shown in FIGURE 9, comprises a capacitive detection unit 902.

The capacitive detection unit 902 comprises a plurality of measurement electrodes 904 and at least one guard electrode 906, for electrically guarding the measurement electrodes 904.

The capacitive detection unit 902 further comprises detection electronics 908, analog and / or digital, for:

polarize the measurement electrodes 904 and the guard 906 at the same potential V _G , called excitation, different from a ground potential at a given frequency, and

- Measuring a signal relating to the electrode-object capacity between each measurement electrode 904 and an object located near, or in contact, with said measurement electrode.

The detection electronics 908 comprises an amplifier 910 for current, or charging, represented by an operational amplifier (AO) 912 and a feedback capacity 914 looping the output of the AO 912 back to the inverter input “- From AO 912.

This detection electronics 908 can be referenced to the excitation potential V _G , or to ground GND.

Furthermore, in the example shown, the non-inverting input “+” of the AO 912 receives the potential V _G and the inverting input “-” of the AO 912 is provided to be connected to each electrode of measurement 904 by means of a scanning means 916, which may for example be a switch, so as to interrogate individually all of the measurement electrodes 904 in turn.

Under these conditions, the charge amplifier 910, and in particular the AO 912, supplies as output a voltage or a signal V _s of amplitude proportional to the coupling capacitance C _eo , called electrode-object capacitance, between the measurement electrode 904 connected to its inverting input “-” and an object close to, or in contact with, said measurement electrode.

The detection electronics 908 may further comprise a conditioner 918 making it possible to obtain a signal representative of the coupling capacity C _eo sought, or of a quantity derived from this capacity, such as distance or contact information. .... This conditioner 918 can include, for example, a synchronous demodulator for demodulating the signal with respect to a carrier, at a working frequency. The conditioner 918 can also include an asynchronous demodulator or an amplitude detector. This conditioner 918 can, of course, be produced in analog and / or digital form (microprocessor) and include any necessary means of filtering, conversion, processing, etc.

At output, the capacitive detection unit 902 provides the value of the signal V _s , therefore representative of the coupling capacity C _eo sought, or of a

- 25 quantity derived from this capacity, such as distance or contact information.

The capacitive detection device 900 comprises the common mode transmitter 202 which transmits a signal in common mode on the differential lines 102 and 104.

The capacitive detection device 900 further comprises a common mode receiver 206 associated with the capacitive detection unit 902.

The common mode signal transmitted by the common mode transmitter 202 is received by the common mode receiver 206. The common mode signal detected by the common mode receiver 206 is supplied to the capacitive detection unit 902 for:

- be used directly as the excitation potential V _G , as shown in FIGURE 9; or

- be used to generate the excitation potential V _G.

In addition, the capacitive detection device 900 comprises a communication module in differential mode 106, and its isolation block 216 of the common mode. The differential module 106 is connected to the output of the capacitive detection unit 902. This differential module 106 therefore receives the signal V _s supplied by the detection unit 902, and transmits it in the differential lines 102 and 104, in mode differential and according to the protocol of this differential interface. This information, namely in particular the value of the signal V _s , is communicated, in differential mode, to another differential communication module (not shown) which can for example be associated with a capacitive detection management unit (not shown) . Of course, the differential module 106 can operate in transmission and reception to receive configuration information, measurement triggering, etc. and to transmit all the information coming from the capacitive detection device 900.

FIGURE 10 is a schematic representation of a second non-limiting embodiment of a capacitive detection device.

- 26 The capacitive detection device 1000, shown in FIGURE 10, comprises “n” capacitive detection unit 902i-902 _n , with n> l.

The capacitive detection device 1000 also comprises the common mode transmitter 202 for transmitting the excitation signal which will be used in each capacitive detection unit 902 ,, and in particular the potential V _G.

To do this, each detection unit 902 is associated with a common mode receiver module 206, to receive the excitation signal transmitted in common mode by the transmitter 202 in common mode.

In addition, each detection unit 902 is associated with a communication module in differential mode 106 ,, and its isolation block of common mode 216 ,, for transmitting in differential mode the information coming from said detection unit 902, to a capacitive detection management unit (not shown), and receive the commands and other information from this capacitive detection management unit.

Of course, the capacitive detection devices can implement the connection device 302 of FIGURE 3 for at least one individual each differential communication module.

FIGURE 11 is a schematic representation of a robot provided with a capacitive detection device according to the invention.

The robot 1100, shown in FIGURE 11, is a robotic arm comprising several articulated segments, and connected to each other by rotary joints.

The robot 1100 has two covering elements 1102 and 1104 arranged on two segments of the robot 1100.

Each covering element 1102-1104 comprises a detection unit, such as for example the detection unit 902 of FIGURE 9.

Each detection unit receives the excitation signal V _G , and emits the measurement signal V _s (in particular), as described above with reference to FIGURES 9 and 10.

The measurement electrodes 904 of each detection unit fitted to the covering elements 1102-1104 are integrated into the thickness of said element.

- 27 of covering, or deposited on one or the faces of said covering element 11021104.

The covering elements 1102-1104 are used either in place of an original covering element of the robot, or in addition to an original covering element.

In this type of application, it is important that the measurement electrodes 904 belonging to separate covering elements 1102-1104 are not detected, so as not to disturb the operation of the device. This is obtained thanks to the invention by transmitting to all the covering elements 10 1102-1104 the same signal in common mode making it possible to generate the same excitation potential V _G.

Of course, the invention is not limited to the examples which have just been described and numerous modifications can be made to these examples without departing from the scope of the invention.

Deposit number: FR1854640

Filing date: 30.05.2018

Submitter: FOGALE NANOTECH

PRELIMINARY RESEARCH REPORT (RRP) RESPONSE MEMORY

1. CONTENTS OF THE PRELIMINARY RESEARCH REPORT

1.1 The Preliminary Research Report cites, in category X, the document US 2009/239559 Al (Dl), and in category Y. the documents Dl and WO 2013/093327 Al (D2).

In his written opinion, associated with the Preliminary Search Report, the Examiner believes that these documents destroy:

- the novelty of claims 1, 2, 5, 11-13: claims 3, 4, 6-10 and 14-19 being recognized as new; and

- the inventive step of all the claims (1-19) of the request.

1.2 In the written opinion, the Examiner noted irregularities concerning the description and invited to cite documents Dl and D2 in the introduction to the patent application. The Examiner is of the opinion that the passage on page 27 lines 14-16 aims to broaden the scope of protection.

Furthermore, the Examiner objects to the attachment of claim 15 and indicates that this claim should be attached to claim 14, due to the use of the expression "each capacitive detection unit".

1.3 In response to the Preliminary Search Report, the Claimant chooses to file a new set of claims in which:

- claim 1 is a new claim obtained by combining claims 1 and 14 as filed; and

- Claims 2-18 correspond respectively to Claims 2-13 and 15-19 as filed.

1/4

2. THE NEW CLAIM 1

2.1. New claim 1 states:

"La) lb) 9.2..8181.88.

le) a éjeœ-Qnmse of déœuugn (908) ucur golunser each electrode of

Id) said capacitive detection device (900; 1000) further comprising a communication device (200; 300), Oèsees + ee— ceeeeweicedee + intended to be implemented with a communication bus in differential mode comprising at least two differential lines (102,104) for conveying a first signal (110) in differential mode between at least two differential communication modules (106i, 106 ₂ ), characterized in that φ + · ίΐ —— ea — wfregue said dlsgositiï de) at least one transmitter (202) in common mode, for injecting the same second signal (210), said in common mode, alternating, on each of said at least two differential lines (102,104), at a point of said communication bus ··; · ,, and lf) at least one receiver (206) in common mode, of said second signal 0.8..8180 9..9881 (89.8..8899 9598y9..9.8li9 .. de..g étectl ou. çugg cl five .. (. 9.02).,. To receive said second signal (210), at another point of said communication bus -.-. ..

g) in which. · tedit second signal injected in

2.2. The new claim 1 therefore relates to a capacitive detection device comprising at least one capacitive detection unit, and a communication device for conveying, in common mode, an excitation signal, or a synchronization signal, to said at least one capacitive detection.

2.3. Novelty

2.3.1. None of the cited documents alone describes all the features of the new claim 1.

2.3.2. In particular, the document Dl does not describe the characteristics la), 1b) the), and ig) The document Dl describes a communication device using a communication bus in differential mode, to communicate both a signal in differential mode and a signal in common mode.

2/4

Document D2 does not describe the characteristics Id), le), If), and 1g). Document D2 describes a capacitive detection device for tactile devices of the smartphone or tablet type.

2.3.3. The new claim 1 therefore satisfies the condition of novelty defined in article L611-11 of the Intellectual Property Code (ICC) in relation to each of the cited documents taken in isolation.

2.4. Inventive step

2.4.1. The closest prior art document appears to be document D2. Indeed, the new claim 1 relates to a capacitive detection device and the document D2 is the only document to relate to a capacitive detection device.

2.4.2. The new claim 1 differs from the teaching of document D2 by the combination of the distinctive characteristics ld) + le) + lf) + lg).

This combination of distinctive characteristics allows a simpler, less expensive and less time-consuming integration of capacitive detection units, in equipment, and in particular in a robot such as a robotic arm (page 2 lines 11-15 and page 2 line 31 on page 3 line 7).

2.4.3. The objective technical problem associated with the distinguishing characteristic can therefore be:

“How to obtain a capacitive detection device whose integration, in equipment, and in particular in a robot such as a robotic arm, is simpler, less expensive and less time-consuming? ".

2.4.4. A person skilled in the art, faced with this objective technical problem, would not obviously end up with the new claim 1.

On the one hand, no document states the objective technical problem. The document Dl does not relate to the field of capacitive detection devices and does not pose any technical problem relating to these devices.

3/4 /

?

On the other hand, even if the person skilled in the art consulted the document D1 and clearly combined it with the document D2 (which the Applicant disputes), it is not clear why it would obviously lead to characteristic 1g), which indicates that it is the common mode signal which is used as excitation or synchronization signal. No technical teaching suggests it, neither in document Dl, nor in document D2. It could completely use the signal in differential mode, which would be different from the characteristic 1g).

2.4.5. Consequently, the new claim 1 satisfies the condition of inventive step defined in article L611-14 of the CPI.

3. CLAIMS 2-18

3.1. Claims 2-18 depend, directly or indirectly, on new claim 1. They are a fortiori new and inventive, at least for the same reasons.

4. CONCLUSIONS

4.1. Consequently, it is requested that the Search Report find that there is no prior art opposable to this application on the basis of the new set of claims.

4.2. The Applicant's representative is at the disposal of the Examiner to discuss this matter with him, during a telephone or informal interview if the latter deems it necessary to expedite the procedure for granting this patent application. .

Claims (18)

1. Device (900; 1000) for capacitive detection of an object comprising at least one capacitive detection unit (902), each comprising: said capacitive detection device (900; 1000) further comprising a communication device (200; 300), intended to be implemented with a communication bus in differential mode comprising at least two differential lines (102,104) for conveying a first signal (110) in differential mode between at least two differential communication modules (106i, 106 ₂ ), characterized in that at least one transmitter (202) in common mode, for injecting the same second signal (210), said in common mode, alternating, on each of said at least two differential lines (102,104), at a point of said communication bus ·· ·; · ,, and -at least one receiver (206) in common mode, dudd.deux; eme..sj.gnai..eQ to receive said second signal (210), at another point of said communication bus-, in 2. Device (.90Q.;. 1.000) .pG9 -; - 3-GO) according to the preceding claim, characterized in that at least one transmitter in common mode (202), and / or at least one receiver (206 ) in common mode includes a block (204,208; 400; 600), called differential mode isolation, with a connection to each differential line (102,104) and a so-called common mode connection, - 29 having an impedance for the signal in common mode (210), between the connections to the differential lines (102,104) and the connection in common mode, lower than an impedance for the signal in differential mode (110), between said connections to the differential lines (102,104). 3. Device (990; .1,000) .p99 -; - 3-G9) according to the preceding claim, characterized in that the isolation block of the differential mode (600) comprises inductors (602,604), called isolation of the differential mode, electromagnetically coupled in opposite directions and arranged to be connected respectively to a differential line (102,104) on the one hand and to the connection in common mode on the other hand. 4. Device (900; 1000) —as claimed in the preceding claim, characterized in that the differential mode isolation block (600) comprises a ferromagnetic core (606) around which the differential mode isolation inductors (602,604) are wound in opposite winding directions, or connected in opposite directions, so as to achieve electromagnetic coupling between said inductors. 5. Device (900; 1000) 99-θ9τ99θ9 according to claim 2, characterized in that the differential mode isolation block (400) includes resistors (402,404), called differential mode isolation, arranged to be connected respectively to a differential line (102, 104) on the one hand and to the common mode connection on the other. 6. Device (990; 10 09) 9909--0909 according to the preceding claim, characterized in that at least one transmitter (202) in common mode comprises a feedback amplifier type circuit (504) of which: - The output is connected in parallel to the insulation resistors of the differential mode (402,404), arranged to be connected respectively to said at least two differential lines (102,104); and - An input is connected in parallel to resistors, called counter-reactors, arranged to be connected respectively to said at least two differential lines (102,104). 7. Device (900; 100Q) f ^ 6Gt39 € H according to claim 5, characterized in that at least one receiver (206) in common mode comprises an amplifier type feedback circuit (506) mounted as a voltage summator , and which : - An input is connected in parallel to the resistors (402,404) for isolating the differential mode, arranged to be connected respectively to said at least two differential lines (102,104); and - The output is connected to said input by at least one counter-reaction resistor. 8. Device (900; 1000) t9-9Gr3999-according to any one of the preceding claims, characterized in that q-uOi ...... that ..... [e ...... device .. ... of ..... communication includes, for at least one differential communication module (1061,1062), a common mode isolation block (216i, 216 ₂ ; 700), with connections to the differential lines (102,104) and connections, called differential mode, to the communication module, having an impedance for the signal in common mode (210), between the connections to the differential lines (102,104) and the connections to the differential communication module (IO61,106 ₂ ), greater than an impedance for the signal in differential mode (110), between the connections to the differential lines. 9. Device. [9Q0; J _; 000> 9-GÔ7-3G93 according to the preceding claim, characterized in that the common mode isolation block (700) comprises inductors (702,704), called common mode isolation, intended to be placed respectively in series between the differential lines (102,104) and the differential communication module (106i, 106 ₂ ), said common mode isolation inductors (702,704) being coupled to each other electromagnetically in an identical sense, or polarity. 10. Device (900; 1000) ...... (· 39 · θγ3 · 9Ο) ....... according to the preceding claim, characterized in that the common mode isolation block (700) comprises a ferromagnetic core (706) around which the common mode isolation inductors (702,704) are wound in identical winding directions, or - 31 connected in identical directions, so as to carry out the electromagnetic coupling between said insulation chokes (702,704). 11. Device (900; 1000) - (3-9-99 according to any one of claims 8 to 10, characterized in that ettei-qua communication device comprises, for at least one differential communication module (106 ₂ ) , a connection module (302) of said differential communication module (106 ₂ ) to the differential lines (102,104), said connection module (302) comprising the common mode isolation block (216 ₂ ) and: - a first connection interface (304) with the differential lines (102,104); and - A second link interface (306) with the differential communication module (160 ₂ ), connected to said first interface (304) downstream of the common mode isolation block (216 ₂ ), seen from said first interface (304 ). 12. Device (900; 1000) 09-99 according to the preceding claim, characterized in that the connection module (302) comprises a third interface for connection (308) to a common mode transmitter, respectively to a common mode receiver (206), connected to the first interface (304) upstream of the common mode isolation block (216 ₂ ), seen from said first interface (304). 13. Device. (9QQ.;. 10Q.Q) é-2W; -3GQ ·) of communication according to any one of the preceding claims, characterized in that ee-te-te device cqmmunteMten further comprises: - a communication bus in differential mode with at least two differential lines (102,104); and - at least one communication module (106i, 106 ₂ ) in differential mode.

^ \ lAà ™oquer Device (900; 1000) according to ..... îa ....... claims 13 ...... and · ...... 14, characterized in that communication module in differential mode (106) is associated with each capacitive detection unit (902), for: - transmitting a detection signal supplied by said capacitive detection unit (902), and / or - receiving a configuration and / or control signal from said capacitive detection unit (902); as the first signal transmitted, respectively received, in differential mode. 4fc | 4 ^ __ Device (900; 1000) according to any one of claims 14 w - 4-Specification, characterized in that at least one capacitive detection unit (902) comprises at least one guard electrode (906) polarized at a guard potential (V _G ), identical or substantially identical to the excitation potential, generated using the second signal. _____Equipment (1100) provided with a detection device according to any one of claims 1-4-to-lSprécédentes. - 33 ^ SvIJh ^^^ Equipment (1100) according to the preceding claim, characterized that: - Its. Oujes detection units are reported to said equipment (1100), and - The differential mode communication bus is a communication bus used in said equipment (1100) between different organs of said equipment (1100). _____Equipment (1100) according to the preceding claim, characterized that it is a robot, a robotic manipulator arm or a robot segment. - 28 CLAIMS 1. Device (900; 1000) for capacitive detection of an object comprising at least one capacitive detection unit (902), each comprising: - at least one measuring electrode (904), and - detection electronics (908) for biasing each measurement electrode (904) to an alternating potential, called an excitation potential, different from a ground potential (GND), and measuring a signal relating to the electrode-object capacitance between each measuring electrode (904) and said object; said capacitive detection device (900; 1000) further comprising a communication device (200; 300), intended to be implemented with a communication bus in differential mode comprising at least two differential lines (102,104) for conveying a first signal (110) in differential mode between at least two differential communication modules (106i, 106 ₂ ), characterized in that said communication device comprises: at least one transmitter (202) in common mode, for injecting the same second signal (210), said in common mode, alternating, on each of said at least two differential lines (102,104), at a point of said communication bus, and at least one receiver (206) in common mode, of said second signal in common mode for each capacitive detection unit (902), for receiving said second signal (210), at another point of said communication bus; wherein, said second signal injected in common mode by the transmitter in common mode is used to generate an excitation signal (V _G ), respectively a synchronization signal, by each detection unit (902). 2. Device (900; 1000) according to the preceding claim, characterized in that at least one transmitter in common mode (202), and / or at least one receiver (206) in common mode comprises a block (204,208; 400; 600), called differential mode isolation, with a connection to each differential line (102, 104) and a so-called common mode connection, having an impedance for the common mode signal (210), between the connections to the lines - 29 differentials (102,104) and the common mode connection, lower than an impedance for the signal in differential mode (110), between said connections to the differential lines (102,104). 3. Device (900; 1000) according to the preceding claim, characterized in that the differential mode isolation block (600) comprises inductors (602,604), called differential mode isolation, electromagnetically coupled in opposite directions and arranged to be connected respectively to a differential line (102,104) on the one hand and to the common mode connection on the other hand. 4. Device (900; 1000) according to the preceding claim, characterized in that the differential mode isolation block (600) comprises a ferromagnetic core (606) around which the differential mode isolation inductors (602,604) are wound in opposite winding directions, or connected in opposite directions, so as to achieve electromagnetic coupling between said inductors. 5. Device (900; 1000) according to claim 2, characterized in that the differential mode isolation block (400) comprises resistors (402,404), called differential mode isolation, arranged to be connected respectively to a differential line (102,104) on the one hand and the connection in common mode on the other hand. 6. Device (900; 1000) according to the preceding claim, characterized in that at least one transmitter (202) in common mode comprises a circuit of the feedback amplifier type (504) of which: - The output is connected in parallel to the insulation resistors of the differential mode (402,404), arranged to be connected respectively to said at least two differential lines (102,104); and - An input is connected in parallel to resistors, called counter-reactors, arranged to be connected respectively to said at least two differential lines (102,104). 7. Device (900; 1000) according to claim 5, characterized in that at least one receiver (206) in common mode comprises an amplifier-type feedback circuit (506) mounted as a voltage summator, and of which: - An input is connected in parallel to the resistors (402,404) for isolating the differential mode, arranged to be connected respectively to said at least two differential lines (102,104); and - The output is connected to said input by at least one feedback resistance. 8. Device (900; 1000) according to any one of the preceding claims, characterized in that the communication device comprises, for at least one differential communication module (106i, 106 ₂ ), a common mode isolation block (216i, 216 ₂ ; 700), with connections to the differential lines (102,104) and connections, called differential mode, to the communication module, having an impedance for the signal in common mode (210), between the connections to the differential lines (102,104) and the connections to the differential communication module (106i, 106 ₂ ), greater than an impedance for the signal in differential mode (110), between the connections to the differential lines. 9. Device (900; 1000) according to the preceding claim, characterized in that the common mode isolation block (700) comprises inductors (702,704), called common mode isolation, intended to be placed respectively in series between the differential lines (102,104) and the differential communication module (106i, 106 ₂ ), said common mode isolation inductors (702,704) being coupled to each other electromagnetically in an identical direction, or polarity. 10. Device (900; 1000) according to the preceding claim, characterized in that the common mode isolation block (700) comprises a ferromagnetic core (706) around which the common mode isolation inductors (702,704) are wound in identical winding directions, or - 31 connected in identical directions, so as to carry out the electromagnetic coupling between said insulation chokes (702,704). 11. Device (900; 1000) according to any one of claims 8 to 10, characterized in that the communication device comprises, for at least one differential communication module (106 ₂ ), a connection module (302) of said differential communication module (106 ₂ ) to differential lines (102,104), said connection module (302) comprising the common mode isolation block (216 ₂ ) and: - a first connection interface (304) with the differential lines (102,104); and - A second link interface (306) with the differential communication module (160 ₂ ), connected to said first interface (304) downstream of the common mode isolation block (216 ₂ ), seen from said first interface (304 ). 12. Device (900; 1000) according to the preceding claim, characterized in that the connection module (302) comprises a third connection interface (308) to a common mode transmitter, respectively to a common mode receiver (206) , connected to the first interface (304) upstream of the common mode isolation block (216 ₂ ), seen from said first interface (304). 13. Communication device (900; 1000) according to any one of the preceding claims, characterized in that the communication device also comprises: - a communication bus in differential mode with at least two differential lines (102,104); and - at least one communication module (106i, 106 ₂ ) in differential mode. 14. Device (900; 1000) according to claim 13, characterized in that a differential mode communication module (106) is associated with each capacitive detection unit (902), for: - transmitting a detection signal supplied by said capacitive detection unit (902), and / or - receiving a configuration and / or control signal from said capacitive detection unit (902); as the first signal transmitted, respectively received, in differential mode. 15. Device (900; 1000) according to any one of the preceding claims, characterized in that at least one capacitive detection unit (902) comprises at least one guard electrode (906) polarized at a guard potential (V _G ), identical or substantially identical to the excitation potential, generated using the second signal. 16. Equipment (1100) provided with a detection device according to any one of the preceding claims. 17. Equipment (1100) according to the preceding claim, characterized in that: the detection unit or units are reported to said equipment (1100), and - The differential mode communication bus is a communication bus used in said equipment (1100) between different organs of said equipment (1100). 18. Equipment (1100) according to the preceding claim, characterized in that it is a robot, a robotic manipulator arm or a robot segment.