CAPACITIVE CASING ELEMENT FOR ROBOT, ROBOT PROVIDED WITH SUCH A CASING ELEMENT

Abstract

A casing element for a robot, the casing element including: at least one capacitive electrode, termed a measurement electrode, intended to be biased to a first AC electric potential that is different from a ground potential, at a working frequency; at least one electrode, termed a guard electrode, arranged beneath the at least one measurement electrode and intended to be biased to an AC electric potential, termed the guard potential, that is identical or substantially identical to the first potential at the working frequency; and at least one dielectric layer, termed a central dielectric layer, arranged between the at least one measurement electrode and the at least one guard electrode. A robot is also provided with at least such a casing element.

Claims

1. A trim element for a robot, in particular provided to be positioned on a segment or an articulation of a robot in place of or in addition to a trim element of said robot said trim element comprising: at least one capacitive electrode, called measurement electrode, provided to be polarized at a first alternating electrical potential different from a ground potential at a working frequency; at least one electrode, called guard electrode, arranged beneath said at least one measurement electrode and provided to be polarized at an alternating electrical potential (V.sub.G), called guard potential, identical or substantially identical to said first potential at said working frequency; and at least one dielectric layer, called central layer, arranged between said at least one measurement electrode and said at least one guard electrode.

2. The trim element according to claim 1, characterized in that it comprises at least one dielectric layer, called external layer, arranged over the measurement electrode(s).

3. The trim element according to claim 2, characterized in that it comprises a rigid, semi-rigid or resilient external layer, and a central layer in the form of a separate element modelled to be inserted into the external layer, and comprising on its faces, respectively, said at least one measurement electrode and said at least one guard electrode.

4. The trim element according to any claim 1, characterized in that it comprises a layer, called bearing layer, arranged beneath the guard electrode(s) and provided to come into contact with a surface of the robot.

5. The trim element according to claim 1, characterized in that it comprises a positioning means, or an index mark, making it possible to mount said trim element on a part of the robot, in a position and orientation that are, or can be, determined.

6. The trim element according to claim 1, characterized in that the central layer is presented in the form of a double-face printed circuit, the measurement electrode(s) being arranged on one of the faces of said printed circuit, and the guard electrode(s) being arranged on the opposite face of said printed circuit.

7. The trim element according to claim 1, characterized in that it comprises at least one detection electronics configured to measure a signal with respect to a coupling capacitance, called electrode-object capacitance, between at least one measurement electrode and a nearby object.

8. The trim element according to claim 7, characterized in that it comprises several detection electronics units, distributed over said trim element, at a distance from one another.

9. The trim element according to claim 2, characterized in that at least one detection electronics is placed between the external layer and a guard electrode.

10. The trim element according to claim 7, characterized in that at least one detection electronics is placed on the central layer.

11. The trim element according to claim 7, characterized in that at least one detection electronics is guarded at the guard potential (V.sub.G) by a guard wall or cover, polarized at the guard potential (V.sub.G).

12. The trim element according to claim 1, characterized in that it comprises at least one wired and/or wireless connection interface arranged for: receiving at least one alternating electrical potential corresponding to the first alternating potential or the guard potential (V.sub.G) or both; and/or transmitting a measurement or detection signal.

13. The trim element according to claim 1, characterized in that the at least one measurement electrode is separated from the at least one guard electrode by a locally elastically compressible layer, so that a bearing pressure on said trim element locally modifies the distance between the measurement and guard electrodes.

14. The trim element according to the claim 13, characterized in that it comprises at least one electronics for the detection of a signal relating to the capacitance and/or the resistance, called inter-electrode capacitance and/or resistance, between the measurement and guard electrodes at the level of said bearing pressure.

15. The trim element according to claim 1, characterized in that it is presented in the form of: a rigid or resilient casing; or a flexible cover provided to be fastened on a trim element of said robot.

16. The trim element according to claim 1, characterized in that it is presented in the form of: an additional casing, or a cover, provided to be mounted on an existing casing of a robot; or a replacement casing provided to be mounted in place of an existing casing.

17. The trim element according to claim 1, characterized in that it comprises two parts, provided to be positioned on either side of a segment or an articulation of the robot, and being fastened together.

18. A robot equipped with at least one trim element according to claim 1.

Description

DESCRIPTION OF THE FIGURES AND EMBODIMENTS

[0129] Other advantages and characteristics will become apparent on examination of the detailed description of examples that are in no way limitative, and from the attached drawings in which:

[0130] FIGS. 1, 2, 3a and 3b are schematic representations in cross section of three embodiments of a trim element according to the invention;

[0131] FIGS. 4a-4c are schematic representations of a robot fitted with two trim elements according to the invention;

[0132] FIGS. 5a and 5b are schematic representations of two embodiments of a set of detection electronics capable of being implemented with a trim element according to the invention; and

[0133] FIGS. 6-7 are schematic representations in cross section of two other embodiments of a trim element according to the invention.

[0134] It is well understood that the embodiments which will be described hereinafter are in no way limitative. Variants of the invention can be envisaged comprising only a selection of the characteristics described hereinafter, in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of 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 alone is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of the prior art.

[0135] In particular, all the variants and all the embodiments described can be combined together if there is no objection to this combination from a technical point of view.

[0136] In the figures, elements common to several figures retain the same reference.

[0137] FIG. 1 is a schematic representation in cross section of a first non-limitative embodiment of a trim element according to the invention.

[0138] The trim element 100, shown in FIG. 1, is a rigid casing that can be used either in place of an existing casing on a robot, or in addition to an existing casing. In this latter case, the trim element 100 is positioned on the existing casing.

[0139] The trim element 100 can be used for fitting to a segment of a robot or an articulation of a robot.

[0140] The trim element 100 comprises several capacitive electrodes 102, called measurement electrodes, and a capacitive electrode 104, called guard electrode, common to the set of measurement electrodes. The guard electrode 104 forms a guard plane covering substantially all the measurement electrodes 102.

[0141] The trim element 100 also comprises a dielectric layer 106, called central layer, positioned between the measurement electrodes 102 and the guard electrode 104.

[0142] The central layer 106 can be produced by a printed circuit, rigid or flexible, on which are deposited, or etched, the measurement electrodes 102 and the guard electrode 104.

[0143] Alternatively, the central layer 106 can be produced from plastic by 3D printing, or by moulding, or also by thermoforming of a substantially flat plastic plate.

[0144] The measurement electrodes 102 can then be deposited on the central layer 106 by:

[0145] spraying metallic particles onto said central layer 106 after having positioned a mask on said central layer; [0146] printing of the ink jet type, or [0147] screen printing.

[0148] The guard electrode 104 can also be deposited on the central layer 106 by painting said central layer 106 with a layer of conductive material.

[0149] The trim element 100 also comprises a dielectric layer 108, called external layer, positioned on the measurement electrodes 102. This external layer 108 is intended to protect the measurement electrodes from external damage such as by impacts, moisture or liquids. This external layer 108 can be bonded on the measurement electrodes 102 or can be produced by depositing a coating on said measurement electrodes 102, such as for example a plastic coating, varnish, etc.

[0150] The external layer 108 is preferably in contact with the measurement electrodes 102 such that there is no free space (or at least no significant air gap) between said external layer 108 and the measurement electrodes 102.

[0151] According to an example embodiment, the external layer 108 can be produced in the form of a rigid, semi-rigid or resilient casing. The central layer 106 can be produced (by moulding, thermoforming or 3D printing) in the form of a rigid, semi-rigid or resilient casing having a complementary shape for insertion into the external layer 108, and comprising on its faces the measurement electrodes 102 and the guard electrode 104.

[0152] According to another example embodiment, the external layer 108 can be produced in the form of a rigid, semi-rigid or resilient casing. The central layer 106 can be produced in the form of a double-face printed circuit board with the measurement electrodes 102 and the guard electrode 104.

[0153] Optionally, the trim element 100 also comprises a dielectric layer 110, called bearing layer, positioned beneath the guard electrode 104. This bearing layer 110 is intended to: [0154] protect the guard electrode 104, and/or [0155] isolate the guard electrode 104 from a conductive surface on which the trim element 100 is positioned, and/or [0156] absorb the surface discontinuities when the trim element 100 is positioned on a surface of a robot, and/or [0157] absorb any impacts that may occur on the trim element during its use.

[0158] The bearing layer 110 can be produced from a flexible material, such as flexible plastic or foam for example.

[0159] The bearing layer 110 can be constituted by layers or coatings of insulation materials.

[0160] In the example shown in FIG. 1, the bearing layer 108 is produced by an assembly of separate bearing elements 112 such as bearing pins or legs.

[0161] The trim element 100 also comprises electronic modules 114, arranged between the bearing elements 112, below the level of the bearing elements, and in particular on the central layer 106, and on the same face as the guard electrode 104.

[0162] In the embodiment presented, the bearing elements 112 of the bearing layer 108 also serve to protect the electronic modules 114 mechanically. The electronic modules 114 are at a distance from one another. Each electronic module 114 comprises at least one detection electronics used for: [0163] polarizing the measurement electrodes 102, with a first alternating electrical potential different from a ground potential of the robot at the working frequency, and [0164] polarizing the guard electrode 104 with an alternating electrical potential V.sub.G, called guard potential, identical to the first potential, at the working frequency.

[0165] Each detection electronics comprises at least one electronic component configured to supply an output signal representative of the capacitance between a measurement electrode 102 and a nearby object.

[0166] Examples of detection electronics are given in greater detail hereinafter with reference to FIGS. 5a and 5b.

[0167] In order to protect each electronic module 114 from any leakage capacitances, the trim element 100 comprises a cover 116, called guard cover, polarized at the guard potential V.sub.G and covering each electronic module 114. The polarization at the guard potential of each cover 116 can be carried out by electrically connecting each cover 116 to the guard electrode 104, itself polarized at the guard potential V.sub.G.

[0168] It should be noted that the cover 116 is not necessarily an external element. It can be produced by a guard wall, for example formed by a layer or a plane of the printed circuit of the electronic module 114.

[0169] FIG. 2 is a schematic representation in cross section of another non-limitative embodiment of a trim element according to the invention.

[0170] The trim element 200 in FIG. 2 comprises all the elements of the trim element 100 in FIG. 1.

[0171] In addition, unlike the trim element 100 in FIG. 1, in the trim element 200 the electronic modules are positioned on the central layer 106 on the side of the measurement electrodes 102, in particular on the face of the central layer 106 comprising the measurement electrodes 102. In this configuration, it is not necessary to use additional guard covers as the electronic modules 114 are guarded at the guard potential by the guard electrode 104, polarized at the guard potential V.sub.G and which in fact constitutes a guard wall for the electronic modules.

[0172] FIG. 6 is a schematic representation in cross section of another non-limitative embodiment of a trim element according to the invention.

[0173] The trim element 600 in FIG. 6 comprises measurement electrodes 102, the guard electrode(s) 104, the central layer 106, the external layer 108, the electronic module(s) 114.

[0174] In the example shown in FIG. 6, the electronic modules 114 are produced in the form of printed circuits separate from the central layer 106 comprising the measurement electrodes 102 and the guard electrode 104. The electronic modules 114 are positioned at the level of this central layer 106 in one or more apertures made through this central layer 106, or on the edges of this central layer 106. The electronic modules 114 can thus be fastened on the external layer 108. They are connected to the measurement electrodes 102 and to the guard electrodes 104 for example by ribbon cables produced with the substrate of the central layer 106. Preferably, the electronic module(s) 114 comprise a guard wall 116 in the form of a layer of the printed circuit.

[0175] FIG. 7 is a schematic representation in cross section of another non-limitative embodiment of a trim element according to the invention.

[0176] The trim element 700 in FIG. 7 comprises the measurement electrodes 102, the guard electrode(s) 104, the central layer 106, the external layer 108, the electronic module(s) 114.

[0177] In the example shown in FIG. 7, the measurement electrodes 102 are produced with a single-face printed circuit 702.

[0178] The guard electrode(s) 104 are also produced with a single-face printed circuit 704.

[0179] The central layer 106 is constituted by a substrate of at least one of the single-face printed circuits 702 and 704, and as shown in the example illustrated in FIG. 7, an intercalated element 706 placed between said printed circuits.

[0180] The electronic module(s) 114 are produced in the form of printed circuits separate from the central layer 106. They are fastened on the external layer 108. They are placed between the external layer 108 and the single-face printed circuit 704 with the guard electrodes 104, and connected to the measurement electrodes 102 and to the guard electrode 104. Thus, the electronic module(s) 114 are protected by the guard electrodes 104.

[0181] FIGS. 3a and 3b are schematic representations in cross section of another non-limitative embodiment of a trim element according to the invention.

[0182] The trim element 300, shown in FIGS. 3a and 3b, comprises all the elements of the trim element 200 in FIG. 2.

[0183] The trim element 300 also comprises a layer 302 that is locally elastically compressible, arranged between the central layer 106 and the measurement electrodes 102. This layer is for example produced from very flexible plastic or foam. This compressible layer 302 makes it possible to vary locally the distance between the measurement electrodes 102 and the guard electrode 104, when a load is brought to bear on the trim element 300.

[0184] FIG. 3a shows the trim element 300 at rest and FIG. 3b shows the trim element 300 when a pressure, represented by the arrow 304, is applied thereto.

[0185] Thus, by measuring the capacitance between the measurement electrodes 102 and the guard electrode 104 it is possible to characterize the pressure exerted. To this end, it is necessary to set the measurement 102 and guard 104 electrodes to different alternating potentials, at the working frequency, at least at the level of the bearing position. To this end, one of the measurement 102 and guard 104 electrodes can be grounded. Alternatively, or in addition, an alternating electrical potential that is non-zero at the working frequency can be introduced between the guard electrode 104 and the measurement electrode 102.

[0186] As an alternative to what has just been described in FIGS. 1, 2, 3a and 3b, the trim element can comprise an individual guard electrode for each measurement electrode, in place of the single guard electrode forming a guard plane.

[0187] Furthermore, it is possible for the detection electronics not to be arranged in the trim element but independently, for example on a printed circuit board independent of the trim element.

[0188] FIG. 4a is a schematic representation of a robot fitted with trim elements according to the invention.

[0189] The robot 400 is a robotized arm comprising several segments connected together by rotary articulations.

[0190] The robot 400 comprises three trim elements 402, 403 and 404 according to the invention, each fitted to a segment or an articulation of the robot, either in place of an original trim element of the robot, or in addition to an original trim element.

[0191] The trim element 403 is a cover that is fastened on an articulation of the robot 400, replacing an existing cover. It therefore fastens into the fastening interfaces (for example threadings or screws) of the original cover.

[0192] FIG. 4b is a schematic representation of the trim element 402 fitted to a segment of the robot 400.

[0193] The trim element 402 has two identical parts 402.sub.1 and 402.sub.2 with a cross section in the form of a half-cylinder. Each part 402.sub.1 and 402.sub.2 is provided to be fastened to the segment of the robot 400 by bonding. Alternatively, each part can be fastened to the segment of the robot by screwing, clipping or by suction-type means, provided on the trim element or on the segment of the robot.

[0194] Visual index marks 402.sub.3, provided on the external faces of the parts 402.sub.1 and 402.sub.2, make it possible to position and correctly orient each part 402.sub.1 and 402.sub.2 of the trim element 402 when it is assembled onto the segment of the robot.

[0195] The trim element 402 also comprises a mechanical positioning element 402.sub.4 in the form of a stud or an element in relief intended to be inserted into a groove or a machined indentation on the robot 400.

[0196] FIG. 4c is a schematic representation of the trim element 404 fitted to another segment of the robot 400.

[0197] The trim element 404 has two identical parts 404.sub.1 and 404.sub.2 with a cross zsection in the form of a half-cylinder. The parts 404.sub.1 and 404.sub.2 are assembled together by a hinge 404.sub.3 allowing mutual rotation between said parts 404.sub.1 and 404.sub.2 such that said parts 404.sub.1 and 404.sub.2 can be open in order to position the trim element around the segment of the robot 400, then closed.

[0198] The part 404.sub.1 comprises one or more assembly means 4044, such as a collar or a clip, being introduced into (or abutting against) an assembly means 404.sub.5 such as an aperture or a tab or also a lip 404.sub.5, provided on the part 404.sub.2, in order to carry out assembly by clamping the trim element 404 around the segment of the robot.

[0199] Visual index marks (not shown), provided on the external faces of the trim element 404 make it possible to position and correctly orient it when it is assembled onto the segment of the robot.

[0200] The trim element 404 can also comprise a mechanical positioning element similar to the element 402.sub.4 of the trim element 402, in the form of a stud or an element in relief intended to be inserted into a groove or a machined indentation on the robot 400.

[0201] FIG. 5a is a schematic representation of a first embodiment of detection electronics capable of being implemented in a trim element according to the invention.

[0202] The detection electronics 500, shown in FIG. 5a, can be, or can be incorporated in, an electronic module 114 in FIGS. 1, 2, 3a and 3b. The detection electronics 500 can be produced in an analogue or digital form, or an analogue/digital combination.

[0203] The detection electronics 500 receives an alternating excitation voltage, denoted V.sub.G, from an oscillator 502 referenced to a ground potential 504. The voltage V.sub.G is used as guard potential for polarizing the guard electrode(s) 104, and as first potential for polarizing the measurement electrode(s) 102.

[0204] The detection electronics 500 comprises a current or charge amplifier, represented by an operational amplifier 506 and a negative-feedback capacitor 508. In the embodiment shown, this charge amplifier supplies at the output a voltage proportional to the coupling capacitance between an electrode 102 and an object in proximity.

[0205] The detection electronics 500 also comprises a conditioner 510 making it possible to obtain a signal representative of the sought coupling capacitance C.sub.eo, and/or the presence or of the proximity of an object or a body. This conditioner 510 can comprise, for example, a synchronous demodulator for demodulating the signal with respect to a carrier, at a working frequency. The conditioner 510 can also comprise an asynchronous demodulator or an amplitude detector. This conditioner 510 can, of course, be produced in an analogue and/or digital form (microprocessor) and comprise all necessary means for filtering, conversion, processing, etc.

[0206] The detection electronics 500 can be dedicated to one measurement electrode 102 so that each measurement electrode comprises its own detection electronics.

[0207] Alternatively, and as shown in FIG. 5b, the detection electronics 500 can be common to several measurement electrodes 102.

[0208] In this case, the detection electronics 500 also comprises a polling means 512 connecting the charge amplifier 506, in turn, to each measurement electrode 102, so as to poll individually each of said measurement electrodes 102.

[0209] Of course, the measurement electronics 500 can comprise components other that those described.

[0210] The detection electronics 500, or at least its sensitive part with the charge amplifier 506 can be referenced (or supplied by electrical feeds referenced) to the guard potential V.sub.G, in order to minimize parasitic capacitances.

[0211] The detection electronics 500 can also be referenced, more conventionally, to the ground potential 504.

[0212] Of course, the invention is not limited to the examples that have just been described, and numerous modifications may be made to these examples without departing from the scope of the invention.