Process for characterizing a part by robotic chemical analysis.

Abstract

The present invention relates to a method for characterizing a part (2) in a system (1) comprising a chemical analysis device (3) and at least one robot (10a, 10b) for manipulating either a gripping device (12b) for grasping said part (2), or said chemical analysis device (3); the method being characterized in that it comprises the implementation of steps of: (c) Determining a first trajectory of the robot(s) (10a, 10b) enabling the placement of at least one target point of said part (2) and said chemical analysis device (3) opposite each other in order to be able to carry out a chemical analysis of the material of said part (2) at the level of said target point;(d) Synchronized control of the robot(s) (10a, 10b) and said chemical analysis unit (3) so as to implement said first trajectory and obtain, during said first trajectory, chemical analysis data at each target point of said part (2) by means of said chemical analysis unit (3); (e) Processing of the chemical analysis data obtained so as to characterize said part (2). Figure for the abstract: Fig 1.;

Description

Title of the invention: Method for characterizing a part by robotic chemical analysis.

[0001] GENERAL TECHNICAL FIELD

[0002] The present invention relates to the field of industrial process robotization, and in particular to quality control by chemical analysis. More specifically, the present invention relates to a method for characterizing a part in a system comprising a chemical analysis device, in particular by atomic emission spectrometry, and at least one robot.

[0003] STATE OF THE ART

[0004] Chemical analysis techniques for a sample by atomic emission spectroscopy are known, and in particular LIBS “laser-induced breakdown spectroscopy” technology (in French laser-induced plasma atomic emission spectrometry or laser-induced plasma optical emission spectrometry).

[0005] This technique is based on the interaction of a pulsed laser with the material to be analyzed, so as to locally vaporize the matter and form a plasma. Analysis of the emission spectrum of the plasma radiation makes it possible to determine the elemental atomic composition of the sample.

[0006] The samples to be analyzed can be very varied (liquid, gas, solid), the analysis is virtually non-destructive (a few micrograms of matter are ablated), inexpensive and rapid, so the applications are extremely numerous.

[0007] For example, it is known to use LIBS integrated into a metallurgical production line to monitor the content of certain metals in near real-time. Similarly, they are found in the nuclear industry, the pharmaceutical sector, the recycling and waste management sector, etc.

[0008] The difficulty lies in the handling of the LIBS system, which at best weighs about ten kilograms, is dangerous, and must be used precisely.

[0009] He has already proposed equipping robots, particularly in space applications, notably the ChemCam instrument on the Curiosity Mars rover (which is mounted on a mast). This makes it possible to "target" targets one by one with the instrument and to perform several hundred shots per day.

[0010] The performance of such robots is however insufficient for a generalized automatic use of the LIBS system in industry: if one wants for example to test all the parts coming out of a production line, it is necessary to be able to carry out hundreds of thousands of shots per day.

[0011] The present invention improves the situation. PRESENTATION OF THE INVENTION

[0012] The present invention therefore relates, according to a first aspect, to a method for characterizing a part in a system comprising: • a chemical analysis device; • at least one robot equipped with actuated joints for manipulation • either a gripping device allowing the said part to be grasped, • or the said chemical analysis device; • data processing capabilities, • at least one detector;

[0013] The process being characterized in that it comprises the implementation by data processing means of steps of:

[0014] (c) Determination, based on data acquired by said detector, of a first trajectory of the robot(s) allowing to place opposite at least one target point of said part and said chemical analysis device in order to be able to implement a chemical analysis of the material of said part at the level of said target point;

[0015] (d) Synchronized control of the robot(s) and said chemical analysis unit so as to implement said first trajectory and obtain, during said first trajectory, chemical analysis data at each target point of said part by means of said chemical analysis device;

[0016] (e) Processing of the chemical analysis data obtained so as to characterize said piece.

[0017] According to advantageous and non-limiting features:

[0018] The system includes a first robot equipped with actuated joints for the manipulation of said chemical analysis organ, said first trajectory being a trajectory of movement of at least said chemical analysis organ by the first robot.

[0019] The system includes a second robot equipped with actuated joints for manipulating a gripping organ for grasping said part.

[0020] The part is initially placed in a first container, in particular in bulk,

[0021] The process includes preliminary steps of: a. Determination, based on data acquired by said detector, of a second trajectory of the second robot enabling the grasping organ of the second robot to grasp said part in the first container and move it to a predetermined position, the first trajectory starting from said predetermined position; b. Control of the second robot so as to implement said second trajectory.

[0022] The second trajectory further includes scanning the surface of said part by the detector.

[0023] The process further comprises the steps of:

[0024] (f) Determination, based on data acquired by said detector, of a third trajectory of the second robot allowing the said part to be placed in a second container selected according to the result of the characterization of step (e), with the gripping organ of the second robot;

[0025] (g) Control of the second robot so as to implement said third path.

[0026] Said first trajectory is a displacement trajectory of at least said part.

[0027] Said first trajectory is a trajectory of simultaneous movement of the part by the second robot and of said chemical analysis organ by the first robot.

[0028] Said chemical analysis organ is fixedly mounted on said system, said first trajectory being a trajectory of movement of the part relative to said chemical analysis organ by the second robot.

[0029] The system includes a protective window for said chemical analysis device.

[0030] Step (c) includes prior to a localization step (cO) of each target point on the part as a function of at least one three-dimensional point cloud of the part, obtained from data acquired by the detector.

[0031] Step (cO) includes the determination of the target point(s) according to the desired characterization.

[0032] Said detector is a camera, in particular stereoscopic.

[0033] Part (2) has a plurality of target points.

[0034] The first trajectory allows each target point of said part and said chemical analysis device to be placed sequentially opposite each other in order to be able to carry out a chemical analysis of the material of said part at each target point.

[0035] A target point of said part and said chemical analysis device are opposite each other if the target point is aligned with an emission direction of an excitation source of said device; a distance between the target point and the excitation source of the device is within a predefined range of operating distances; and an angle between said emission direction of the excitation source of the device and the normal to the surface of the part at said target point is within a predefined range of operating angles.

[0036] The first trajectory maintains said distance between the target point and the source of excitation of the organ within the predefined range of operating distances.

[0037] The first trajectory maintains said angle between said direction of emission of the excitation source of the organ and the normal to the surface of the part at said target point in the predefined range of operating angles, between two target points.

[0038] Said chemical analysis organ is an atomic emission spectrometry organ, in particular of the laser-induced plasma atomic emission spectrometry type, LIBS.

[0039] According to a second aspect, the invention proposes a system for characterizing a part, comprising • a chemical analysis device; • at least one robot equipped with actuated joints for manipulation • either a gripping device allowing the said part to be grasped, • or the said chemical analysis device; • data processing capabilities; • at least one detector;

[0040] characterized in that the data processing means are configured to: - Determine, based on data acquired by said detector, a first trajectory of the robot(s) allowing to place opposite at least one target point of said part and said chemical analysis device in order to be able to implement a chemical analysis of the material of said part at the level of said target point; - To control in a synchronized manner the robot(s) and the said chemical analysis device so as to implement the said first trajectory and to obtain, during the said first trajectory, chemical analysis data at each target point of the said part by means of the said chemical analysis device; - Process the chemical analysis data obtained in order to characterize the said part.

[0041] According to a third and fourth aspect, the invention provides a computer program product comprising code instructions for executing a process according to the first aspect of characterizing a part in a system; and a computer-readable storage means on which is stored a computer program product comprising code instructions for executing a process according to the first aspect of characterizing a part in a system. PRESENTATION OF FIGURES

[0042] Other features and advantages of the present invention will become apparent from the following description of a preferred embodiment. This description will be given with reference to the accompanying drawings in which:

[0043] [Fig.1] [Fig.1] is a general diagram of a system for implementing the method according to the invention;

[0044] [Fig.2a] [Fig.2a] illustrates a first embodiment of the system for implementing the process according to the invention;

[0045] [Fig.2b] [Fig.2b] illustrates a second embodiment of the system for implementing the process according to the invention;

[0046] [Fig.3] [Fig.3] is a flowchart representing the steps of an embodiment of the process according to the invention.

[0047] [Fig.4] [Fig.4] represents a particular case of so-called autofocus mode during the implementation of the method according to the invention. DETAILED DESCRIPTION

[0048] Architecture

[0049] With reference to [Fig. 1], the present invention relates to a method for characterizing a part 2 in a system 1, said part 2 being advantageously arranged in any manner within a first container 21, and in particular in bulk (meaning that there are a plurality of the first part 2 in said first container 21), even if it is possible that the part 2 may already be arranged in an orderly manner, for example, placed on a suitable support of said system 1, or even on a conveyor belt. It should be noted that "arranged in bulk" means arranged in a non-orderly and generally random manner: upon opening the containers, the position of the parts inside and their arrangement is unpredictable.

[0050] Characterization of part 2 means determining the properties of part 2, such as material identification, qualitative or quantitative elemental analysis, chemical imaging, elemental distribution, etc. It should be noted that said characterization of part 2 may be global (i.e., concerning the entire part) or local. In the latter case, said characterization advantageously includes a mapping component of part 2 (see below). In all cases, the result of the characterization may be a classification of the part, in particular among several predefined classes, and especially classes for accepting or rejecting the part.

[0051] For example, in an industrial process, particularly a metallurgical one, there may be a large number of copies of said part 2 freshly manufactured, and said characterization is a non-destructive quality control, allowing verification that each copy has an acceptable chemical composition.

[0052] One or more second containers may be used to receive the assembled parts, advantageously one second container per possible class (for example one for accepted part 2 and one for rejected part 2 in the case of binary classification of the quality control type).

[0053] The first and second containers (or receptacles) 21, 22 are typically crates, opened so as to allow access to the parts inside and to grasp them individually.

[0054] It is understood that the process may, where appropriate, include an inherent component of depalletizing (of part 2), in addition to characterization, the two being able to be done simultaneously, without going through a phase of repositioning the depalletized parts.

[0055] The system 1 for implementing the present process further comprises a chemical analysis element 3, advantageously of the atomic / optical emission spectrometry (AES / OES) type and in particular laser-induced plasma atomic emission spectrometry (LIBS), but it may alternatively be of the spark or arc spectroscopy (Spark OES) type, X-ray fluorescence spectroscopy (XRF), or any other technique known to those skilled in the art consisting of exciting a sample and observing the emission spectrum.

[0056] Thus in all cases, the chemical analysis unit 3 includes an excitation source and an optical sensor, generally a spectrometer, often equipped with an optical fiber, classically capable of recording line spectra in the wavelength range from the near ultraviolet (UV) to the near infrared (IR) through the visible (approximately 200-800 nm).

[0057] In the preferred embodiment of a LIBS, said excitation source is a pulsed laser (i.e., with an ultrashort pulse, in particular of less than one microsecond or even less than one nanosecond), preferably focused. In the case of a Spark laser, it is an electric arc. As will be seen later, said component 3 thus preferentially has a range of valid operating distances, or even an optimal operating distance in particular, corresponding notably to a focusing depth of field of the laser beam. It is understood that this operating range is defined by the hardware, in particular the laser and its optics for a LIBS, and even though LIBS are known to operate up to several meters and, conversely, optimal LIBS at a distance of a few microns, a component with an optimal operating range of a few centimeters will preferably be chosen, given the usual amplitudes and precision of robotic arms 10a, 10b.

[0058] The energy per pulse is very low, less than 1 joule, but in view of its ultra-short duration, colossal powers are mathematically reached.

[0059] By exceeding an "ablation threshold" of the material of part 2, the material is vaporized at the point of laser impact. The generated gas absorbs part of the laser radiation. It heats up and is partially ionized, which immediately causes The formation of a "micro" plasma containing electrons, atoms, and ions in an excited state. The pulse thus both generates the plasma and optically excites the atomic and ionic species it contains. This then emits radiation. The temperature of this micro-plasma can reach tens of thousands of degrees Celsius.

[0060] Excited atoms and ions, upon de-excitation, emit a spectrum consisting of atomic lines, the wavelength of which allows the elements present to be identified.

[0061] The position of the lines provides information on the elements present in the sample, and their intensity is related to the concentration of the sample. Thus, it is possible to identify the elements present in the material at the point of impact and to quantify them.

[0062] Advantageously, system 1 may include another component for analyzing part 2, in particular coupled with component 3, such as a profilometer, an acoustic sensor, etc. The idea is to be able to combine chemical analysis with another analysis, in particular mechanical or physical, of part 2.

[0063] System 1 further comprises data processing means 4, 5 and at least one robot 10a, 10b (potentially two). In the example in [Fig. 1], there are two robots designated as first robot 10a and second robot 10b. In [Fig. 2a] there is only first robot 10a, and in [Fig. 2b] there is only second robot 10b. It should be noted that second robot 10b can play the role of first robot 10a; all possible configurations will be explained later.

[0064] The data processing means 4, 5 are typically a processor, and are in particular intended to control the robots 10a, 10b, and the chemical analysis unit 3 and to process the data obtained by the chemical analysis unit 3. In the example of [Fig. 1], on the one hand there are first data processing means 4 located locally and directly connected to the robots 10a, 10b, and the chemical analysis unit 3, advantageously configured to control the robots 10a, 10b, and the chemical analysis unit 3; and on the other hand there are second data processing means 5 potentially remote and connected to the first data processing means 4 by a network 40 such as the internet, advantageously configured to process the data obtained by the chemical analysis unit 3 and transmitted via the first means 4.

[0065] These means 4 and 5 are, for example, the data processing means of two computers, such as a laptop and a server. It will be understood that means 4 and 5 can be considered equivalent.

[0066] The system 1 further typically includes data storage means 6 (memory, again potentially that of the PC and / or the server), a possible interface 7 (for example a touch screen), and a support structure 8 for the robots 10a, 10b featuring in particular a platform for placing containers 21, 22 and on which interface 7 can be mounted.

[0067] System 1 further comprises at least one detector 9, i.e., a "scanner," for observing part 2 and, in particular, for providing data to recognize and locate it, also connected to the processing means 4, 5. Any radiation sensor (in particular optical) providing data for reconstructing a three-dimensional point cloud may be used, for example, a camera, in particular a stereoscopic one. For example, said detector 9 can acquire two two-dimensional images ("visible," in particular color, i.e., RGB, but alternatively in grayscale) from neighboring viewpoints (called twin images) from which the point cloud can be reconstructed, and for this purpose may include two cameras. Alternatively, detector 9 can obtain a depth image by any known technology, for example, LIDAR, sonar, or even a camera and a structured light projector, etc.As explained, we can have several detectors (9) in order to multiply the viewpoints and, if necessary, prevent obstructions.

[0068] In all cases, the detector 9 is arranged so as to see the parts 2, i.e., either statically, i.e., fixed, or mounted on one of the robots 10a, 10b (as in [Fig. 1]), and in all cases capable of acquiring a three-dimensional point cloud, and generally a two-dimensional image. It should be noted that said detector 9 may be an optical sensor that is identical to the optical sensor of the chemical analysis unit 3.

[0069] Robot(s)

[0070] The system includes at least one robot 10a, 10b equipped with actuated joints 1la, 11b for the manipulation of either a grasping member 12b for grasping said part 2, or said chemical analysis member 3.

[0071] We therefore have two alternatives, and we designate: • first robot 10a the robot equipped with actuated joints lia for the manipulation of said chemical analysis organ 3; • second robot 10b the robot equipped with actuated joints 11b for the manipulation of a grasping organ 12b allowing to grasp said part 2.

[0072] In other words, the first robot 10a is directly equipped with said chemical analysis organ 3, or at least with its excitation source. It will be understood that the latter can be mounted on the first robot 10a (i.e., in a fixed manner, as in [Fig. 2a] which will be described later), or that the latter itself has a grasping organ for grasping said chemical analysis organ 3 (not shown).

[0073] Several embodiments of the invention are possible with the first and / or the second robot 10, 10b: • according to a first embodiment, corresponding to [Fig.2a], we only have the first robot 10a, • according to a second embodiment, corresponding to [Fig.2b], we only have the second robot 10b, • according to a third embodiment, not shown, we have both the first robot 10a and the second robot 10b, • according to a “hybrid” mode between the first and second embodiments, there is a single robot having in turn the roles of the first robot 10a and the second robot 10b, having for this purpose a grasping organ 12b used to successively grasp the part 2 and the chemical analysis organ 3.

[0074] It will be noted that in the case of the third embodiment of two robots 10a, 10b, the latter are "distinct", in that they are manipulable independently so that the first robot 10a can move the chemical analysis organ 3 relative to the second robot 10b and the second robot 10b can hold and move the part 2 relative to the first robot 10a, i.e. they have different actuated joints, but they can "be part" of the same large robot.

[0075] A robot such as the first or second robot is generally called a "robot arm" because the actuated joints 1a, 11b, or "joints" allow it to change position and thus move a part 2 / 1'organ 3. In the example of figures 2a, 2b, the robot 10a, 10b is of the Staübli RX160 type with 6 actuated joints lia, 11b, but any other architecture will be possible, including Cartesian robots, because the notion of actuated joints will be interpreted broadly.

[0076] The gripping member 12b of the second robot 10b is typically a two-jaw gripper, actuable independently of the joints, so as to "grasp" or "release" a part 2, and is generally located at the end of the arm so that all the joints 11b contribute to moving this gripping member 12b. Similarly, in the case of the first robot 10a, the chemical analysis member 3 or at least its source of excitation is generally located at the end of the arm so that all the joints 1 contribute to moving this chemical analysis member 3.

[0077] The detector 9 is typically also at the end of the arm, so as to move in conjunction with the grasping organ 12b / chemical analysis 3.

[0078] For convenience, in the following description, the "position" of a robot 10a, 10b will be designated as the value of the position vector of each joint, denoted [j1, j2, j3, j4, j5, j6] in the case of the 6-axis robot. It is assumed that a dynamic model of the robot is available that allows a spatial position [X, Y, Z] (in a given coordinate system - in particular orthonormal) of the grasping organ 12b / of chemical analysis 3 to be matched with a position [j1, j2, j3, j4, j5, j6] of the robot 10a, 10b.

[0079] In a conventional manner, the robot(s) 10a, 10b can implement an anti-collision mechanism, i.e. that it(s) is / are capable of estimating a force exerted by said joints actuated during a trajectory, in particular to detect an abnormal force representative of an impact against an obstacle (force greater than a safety threshold): the robot 10a, 10b then stops instantly.

[0080] As explained, the present process may involve the unpacking of part 2 by the second robot 10b.

[0081] Process

[0082] We will define the general framework of the process and the principle of the invention, and then we will describe the various embodiments mentioned.

[0083] In all cases, we can start from a state in which part 2 is in a predefined waiting position (for example placed on a support, or a conveyor - or directly held by the gripping device of the possible second robot 10b), if part 2 is not arranged in bulk, or even if an operator manually gives part 2 to the second robot 10b.

[0084] Alternatively, with reference to [Fig.3], the method can begin with optional steps (a) of determining a second trajectory of the second robot 10b enabling it to grasp said part 2 in the first container 21 and move it to said waiting position; and (b) of controlling the second robot 10b so as to implement said second trajectory.

[0085] The second trajectory of the second robot 10b advantageously comprises successively: - An initial phase, in which the first robot 10a moves from a starting position to a gripping position in which the gripping organ 12a of the first robot 10a can grasp the part 2 (in the first container 21); and - An approach phase, in which the first robot 10a moves, holding the part 2, from the gripping position to the waiting position.

[0086] Step (b) then includes, where appropriate (if the waiting position corresponds to a position in which the part 2 is placed on a support, preferably, if the first robot 10a is the same as the second robot 10b), the placement of said part 2 by the gripping member 1 of the first robot 10a.

[0087] These steps (a) and (b) are generally known to a person skilled in the art, who may refer in particular to application FR2204180: - step (a) may include the prior localization of said part 2 in the first container 21 based on at least one three-dimensional point cloud of the part(s) arranged, in particular, in bulk in the first container 21, obtained from data acquired by detector 9 (including, where appropriate, a calibration phase using known means, and / or an environmental scan) - the second trajectory can be determined by a planning algorithm, knowing the required passage positions, a geometry of part 2(s), and possibly the environment (to avoid collisions); - The execution of a trajectory is done with an appropriate controller of the actuated joints 11b of the second robot 10b.

[0088] When the data acquired by the detector 9 includes at least one image, step (a) advantageously comprises segmenting the image so as to restrict the point cloud to the part 2. The idea is to facilitate the subsequent steps by discarding parts of the point cloud representing other parts. This can be done using a neural network trained for this purpose, for example Mask-RCNN or one of its derivatives.

[0089] It should be noted that said second trajectory determined in step (a) may alternatively or in addition include a scan of all or part of the surface of part 2 with detector 9, particularly if its surface is partially obscured, for the purpose of chemical analysis. In practice, this scan makes it possible to acquire the data from which a three-dimensional point cloud representing the part as completely as possible can be constructed. To put it another way, the second robot 10b can move so that detector 9 and part 2 move relative to each other: - if detector 9 is static, the second trajectory includes between the gripping position and the waiting position a phase during which part 2 is presented to detector 9, for example by rotating it so that the latter scans its entire surface; - if detector 9 is mounted on the first robot 10a, the second trajectory may include, in parallel with the movement of part 2 to said waiting position by the second robot 10b, the movement of the first robot 10a so as to move detector 9 around part 2. The scan may take place while the part is temporarily immobilized, for example in the gripping position or in the waiting position, or dynamically during its movement (i.e. both robots 10a, 10b move simultaneously), for maximum execution speed; - If detector 9 is mounted on the second robot 10b, it is understood that this robot has both the role of moving part 2 and scanning. The second trajectory can therefore include the scanning phase when the part 2 is not held by organ 12, before (therefore in container 21 - if possible) or after the movement to the waiting position.

[0090] Note that if part 2 were directly in the waiting position (for example placed by an operator), said second trajectory could only include said scan of the surface of part 2 with detector 9, if necessary by performing a loop in which the part returns to the waiting position.

[0091] Next, the method includes main steps (c) of determining a first trajectory of the robot(s) 10a, 10b allowing to place opposite at least one target point of said part 2 and said chemical analysis device 3 in order to be able to carry out a chemical analysis of the material of said part 2 at the level of said target point; and (d) of synchronized control of the robot(s) 10a, 10b and said chemical analysis device 3 so as to carry out said first trajectory and obtain, during said first trajectory, chemical analysis data at each target point of said part 2 by means of said chemical analysis device 3.

[0092] In other words, instead of specifically "aiming" at the target points one by one with a positioning, adjusting, firing, positioning, adjusting, firing, etc. type strategy, which is laborious, a quality trajectory passing through all firing positions is directly determined, a trajectory executed agnostically by the robots 10a, 10b without regard to the component 3. Thus, only known and proven mechanisms for generating trajectory and guiding robots 10a, 10b are used to implement automatically, reliably and very quickly the chemical analysis of several hundred target positions on a single part, in a few seconds.

[0093] By "placing opposite" (or placing facing each other), we mean placing in such a way that the component 3 is correctly positioned opposite the part 2 to perform the chemical analysis. It should be remembered that the component 3 is primarily an optical instrument, so it must "see" the target point in order to operate on it. Preferably, a target point on said part 2 and said chemical analysis component 3 are considered to be opposite each other if three conditions are met: - the target point is aligned with an emission direction of the excitation source of said organ 3, (i.e., an axis of the laser beam in the case of a LIBS, that is to say, the "firing direction" of the laser - it being understood that the laser could be extended by an optical fiber and therefore that the emission direction must be understood as that at the end of the optical fiber). In other words, an activation of said emission source excites the matter at said target point; - the distance between the target point and the excitation source of organ 3 is within a predefined range of operating distances (said range being a function of the laser's focusing depth of field in the case of a LIBS, for example a range of a width of a few centimeters, or even a few millimeters, for example up to 1 cm around an optimal value of 15 cm), preferably as close as possible to an optimal distance in said range; - The angle between the emission direction of the excitation source of organ 3 and the normal to the surface of part 2 at the target point (the approach angle) is within a predefined range of operating angles, specifically below a threshold (i.e., the range is [0, 0s], where 0s is the threshold, for example, 30°). Indeed, the firing must be as orthogonal as possible to the surface of part 2 for maximum ablation.

[0094] Thus, it is sufficient to generate a first trajectory which respects, for each of the target points, the aforementioned criteria.

[0095] It is recalled that the first trajectory may involve the first and / or the second robot 10a, 10b, i.e. the part 2 and / or the organ 3 can in practice move, since only their relative positions matter.

[0096] In the case of multiple target points, the first trajectory allows each target point of said part 2 and said chemical analysis device 3 to be sequentially positioned opposite each other in order to perform a chemical analysis of the material of said part 2 at each target point. To put it another way, the first trajectory has as many waypoints as there are target points. It is understood that the order of these waypoints is not important, and therefore there are a large number of possible trajectories, although the shortest possible trajectory will be preferred.

[0097] Again, the first trajectory must respect, for each of the points of said plurality of target points, the aforementioned criteria.

[0098] In an optimal embodiment, known as autofocus or "constant focusing" (see [Fig. 4]), it can be assumed that the initial trajectory continuously respects (at least during a main phase in which it passes opposite each target point; i.e., this is always true between two target points, although it is understood that the component 3 and the parts will obviously move apart at the beginning and end of the trajectory) the two criteria related to distance and angle, i.e., maintains the distance between the component 3 and the part 2 and the approach angle constant or nearly constant. This guarantees maximum and constant measurement quality.

[0099] From a mathematical point of view, the implementation of step (c) is no more complicated than step (a), because knowing the position of said target point (in a reference frame of part 2), one can calculate the position of the component 3 in which it is opposite, and generate the first trajectory accordingly by considering these positions as passage points and respecting any criteria.

[0100] The first trajectory can thus be determined by a planning algorithm (in the same way as the possible second trajectory), knowing the required passage position(s) defined by component 3 and a geometry of parts 2 (position of target points), and again possibly the environment (position of any obstacles). As explained, existing trajectory generation algorithms can continue to be used as is.

[0101] It is recalled that part 2 can move relative to component 3 and / or component 3 can move relative to part 2, it will just be necessary to define a suitable relative reference frame.

[0102] Furthermore, step (c) advantageously includes, in the same way as in step (a), a preliminary localization step of said part 2 and more precisely of each target point as a function of at least one three-dimensional point cloud of part 2, obtained from data acquired by the detector 9. One or more target points may be predetermined (i.e., with given coordinates in a reference frame of the part), or corresponding to points of interest of part 2 (for example, "suspect" points which have an unusual appearance, or sensitive areas such as welds which one wishes to check), or chosen dynamically according to the desired characterization.

[0103] Thus, according to a preferred embodiment, step (cO) includes the determination of the target point(s) (in other words, selection of the target points from among the possible points on part 2), according to the desired characterization.

[0104] For example, said selection may be based on a model (i.e., a plan, a representation, or even a three-dimensional model) of the part available to the data processing means 4, 5 (the points of interest may be pre-positioned in the model). Thus, one or more models of different parts 2 may be stored by the data storage means 6, the step (c0) comprising the recognition of the part 2 (advantageously always from the point cloud obtained by the detector 9, possibly segmented), the loading of the corresponding model, and the selection of the points based on said model.

[0105] Alternatively, the data processing means 4, 5 may be capable of implementing a detection algorithm (direct – without necessarily having a model of part 2) for points of interest based on a criterion (appearance, color, etc.) or even artificial intelligence such as a neural network. It should be noted that the selection may remain completely random, particularly in a quality control case, but there will indeed be a precise firing of the component 3 at this randomly selected point, and not a random firing of the component 3, which could be dangerous and in practice would be of little use.

[0106] Alternatively, one may wish to map part 2 completely, or at least a part of the part, in order to, for example, carry out a characterization This is especially important if part 2 is large. In this case, a set of target points is selected to cover all or part of part 2, preferably distributed evenly. For example, one or more target point densities (number of target points per unit area of ​​part 2) can be defined, and in step (c0), the set of points distributed to meet the desired density(s) is / are determined. Note that the density may not be uniform: a high target point density may be present in a critical area of ​​part 2, and a lower target point density in the remaining area (corresponding to a second part of part 2).

[0107] It is noted that the autofocus mode is particularly suitable in the case of mapping with a large number of points.

[0108] The present invention will not, however, be limited to any particular strategy for selecting points of interest; it is sufficient that the system 1 can identify in one way or another at least one target point of the part 2, and construct a first trajectory enabling the organ 3 to be placed opposite this target point in order to carry out a chemical analysis there.

[0109] If this has not taken place before (in particular in step (a), during the second trajectory), step (c0) may include scanning all or part of the surface of part 2 with detector 9.

[0110] Step (d) comprises two aspects: - the control of the robot(s) 10a, 10b so as to implement said first trajectory, in the same way as in possible step (b); - the control of said chemical analysis unit 3 so as to obtain, during said first trajectory, chemical analysis data at each target point of said part 2 by means of said chemical analysis unit 3. This aspect consists of activating the unit 3 at each point along the first trajectory where the unit 3 is opposite a target point, i.e., triggering the laser beam at each target point and observing the result. The data obtained at each activation of said chemical analysis unit 3, transmitted to the processing means 4, 5, are called chemical analysis data.

[0111] It is simply a matter of the commands being correctly synchronized, which is not a problem as the existing controllers can track the progress of the first trajectory in real time and trigger the activation commands for component 3 with ultra-precise accuracy. To reiterate, the first trajectory is implemented as intended; the robot 10, 10b does not concern itself with component 3; the activations of component 3 are simply added afterward in a coordinated manner.

[0112] Note that the first trajectory can be slowed down or even stop for a predetermined time each time the component 3 comes into contact with a target point, the The time required for chemical analysis is implemented, which allows for some tolerance in terms of command synchronization. However, preferably the first trajectory is continuous and at a substantially constant speed, i.e., robots 10a, 10b do not stop and activations are made at precisely the right time, which significantly accelerates the process.

[0113] Preferably, step (d) also includes using detector 9 to confirm the progress of the first trajectory and the correct positioning of component 3 relative to part 2 at each target point. Again, this is merely a confirmation, particularly for traceability purposes, since there is normally no need to correct the trajectory once it has been defined and initiated, unless, for example, the robot 10a, 10b has been hindered by an unexpected obstacle. In such a case, the process should be restarted.

[0114] Thanks to these steps (c) and (d), the present method makes it very easy to carry out the analysis of any target point of any quantity of parts 2 of any shape, including bulk parts, using reliable and proven robot control techniques.

[0115] Note that step (d) may, if the system 1 further includes another measuring device, have its control also synchronized with the robot(s) 10a, 10b and said chemical analysis device 3 so as to obtain, during said first trajectory, other analysis data at each target point of said part 2 by means of said other measuring device.

[0116] This is automatic or almost automatic if said other measuring element is coupled with element 3.

[0117] The process then includes a step (e) of processing the chemical analysis data obtained (for each target point) so as to characterize said part 2. If there are any other measurement data, they can be processed together.

[0118] This step, as explained, can be implemented in any known manner (material identification, qualitative or quantitative elemental analysis, chemical imaging, element distribution), and where appropriate include a classification of part 2

[0119] Step (e) may alternatively or in addition include the generation of a map of all or part of the room in the case of distributed target points.

[0120] For example, it is possible to define which parts of part 2 are made of which material, whether there are any contaminations, etc. This is particularly interesting in the nuclear industry, especially if part 2 is an irradiated part or a part resulting from dismantling.

[0121] In optional final steps (f) and (g) (the characterized part could simply be dropped by the second robot 10b, or retrieved by a operator), the processing means 4 determine a third trajectory of the second robot 10b allowing the part 2 to be deposited into another container 22 (called second container) according to the result of the characterization of step (e); and finally command the second robot 10b so as to implement said third trajectory.

[0122] Preferably, said characterization is, as explained, a classification, and we can have a second container 22 per predefined class, and we place each piece 2 in the second container 22 which corresponds to the class which has been determined for it.

[0123] These steps can again be implemented similarly to steps (a) and (b).

[0124] First embodiment - embedded mode

[0125] According to [Fig. 2a], only the first robot 10a can be used for manipulating said chemical analysis unit 3, said first trajectory being a trajectory of movement of at least said chemical analysis unit 3 by the first robot 10a, and even of movement of only said chemical analysis unit 3 by the first robot 10a. Note that it is possible to manipulate only the excitation source of the unit 3 and to leave its optical sensor (spectrometer) fixed.

[0126] As explained, component 3 is at a minimum held by the first robot 10a, or even fixed to it. In particular, it can be integrated into a housing mechanically interfaced with the joints 1la of the robot 10a, hence the term embedded mode.

[0127] Part 2 remains fixed in the sense that it is not manipulated by robot 10a, but it could, for example, be moved by a conveyor. If necessary, this movement should be taken into account when generating the first trajectory in step (c).

[0128] This embodiment is particularly suited to characterizing parts 2 at the output of a production line.

[0129] Second embodiment - fixed station mode

[0130] According to [Fig.2b], only the second robot 10b can be used for the manipulation of a gripping organ 12b to grasp said part 2, said first trajectory being a displacement trajectory of at least said part 2, relative to said chemical analysis organ 3, and even of displacement of only said part 2 by the second robot 10b.

[0131] The component 3 is fixedly mounted on said system 1. It is therefore understood that the second presents the part to the component 3. This embodiment is particularly suitable with a de-racking component, because the second robot 10b can directly grasp the part 2 in a container 30 (a platform acting as a container can be seen in [Fig.2b] on which a plurality of interlocking parts 2 are arranged).

[0132] Preferably, the system 1 includes a protective window 30 for said chemical analysis unit 3. In other words, the unit 3, or at least its excitation source, is positioned behind this window 30, while the first robot 10a, and therefore the part 2, is on the other side: the laser beams are through said window 30. To reformulate further, the second robot 10b presents the part in front of the window 30, which allows the part to be characterized while keeping the unit 3 protected.

[0133] This embodiment is particularly suited to characterizing parts in a complex environment (radioactivity, toxicity, corrosion, temperature, etc.), because robots adapted to such environments are known, unlike the components 3. For example, it can be used in the dismantling of nuclear installations.

[0134] Third embodiment - double mode

[0135] In this mode, we have the two robots 10a, 10b as in [Fig.1].

[0136] In other words, we have both the first robot 10a, for the manipulation of said chemical analysis organ 3, and the second robot 10b, for the manipulation of a grasping organ 12b allowing to grasp said part 2. Therefore, both part 2 and organ 3 are mobile.

[0137] Said first trajectory is thus: • either a trajectory of simultaneous movement of said part 2 and of the chemical analysis unit 3 (respectively by the second robot 10b and by the first robot 10a), which allows to go even faster for example for a complete characterization of part 2; • either a trajectory solely for chemical analysis 3 (by the first robot 10a), with the second robot 10a performing a second and / or third trajectory as defined previously (steps (b) and (g))-

[0138] Indeed, this third mode is particularly suitable for unpacking with placement of parts in second containers 22 according to the result of the characterization: the second robot 10b moves (first trajectory) and holds the part 2 fixed while the first robot 10a scans it with the on-board organ 3 (second trajectory), then finally the second robot 10b places it according to the result of step (e).

[0139] This embodiment is particularly suited to a classification of parts 2 received in bulk, the parts being automatically unpacked, sorted and checked (in terms of quality)

[0140] Fourth embodiment - hybrid mode

[0141] In this mode (not shown), a single robot plays alternately the role of first and second robot 10a, 10b.

[0142] This mode provides essentially the same effects as the third mode, but at a lower cost because only one robot is required. However, the process is slower.

[0143] To do this, the robot 10a, 10b has a grasping organ 12b allowing it to grasp either the said part 2, or the organ 3.

[0144] The robot 10a, 10b moves (first trajectory) and places part 2 in a waiting position (on a support). It then picks up part 3 to scan it (second trajectory) and places part 3 back down. Then it picks up part 2 again and places it according to the result of step (e).

[0145] System

[0146] According to a second aspect, the invention relates to the system 1 for implementing the method according to the first aspect.

[0147] The system includes • a chemical analysis device 3, in particular of the LIBS type; • at least one robot 10a, 10b, and advantageously two, equipped with of actuated joints lia, 11b for manipulation • either a gripping device 12b allowing the grasping of said part 2 (called second robot 10b), • either said chemical analysis unit 3 (called first robot 10a); • data processing means 4, 5 (and possibly a memory 7 and an interface 8); • at least one detector 9, such as a stereoscopic camera.

[0148] The data processing means 4 are configured to: - optionally, determine, based on data acquired by said detector 9, a second trajectory of the second robot 10b allowing to grasp said part 2 in the first container 21 with the grasping organ 12b of the second robot 10b and move it to a predetermined position, the first trajectory starting from said predetermined position; - Optionally, order the second robot 10b so as to implement said second trajectory; - Determine, based on data acquired by said detector 9, a first trajectory of the robot(s) 10a, 10b allowing to place opposite at least one target point of said part 2 and said chemical analysis device 3 in order to be able to carry out a chemical analysis of the material of said part 2 at the level of said target point; - To control in a synchronized manner the robot(s) 10a, 10b and the said chemical analysis unit 3 so as to implement the said first trajectory and obtain, during the said first trajectory, data chemical analysis at each target point of said part 2 by means of said chemical analysis device 3; - Process the chemical analysis data obtained in order to characterize said part 2; - Optionally, determine, based on data acquired by said detector 9, a third trajectory of the second robot 10b allowing to deposit said part 2 into a second container 22 selected according to the result of the characterization of step (e), with the gripping organ 12b of the second robot 10b; - Optionally, order the second robot 10b so as to implement said third trajectory.

[0149] Computer program product

[0150] According to a third and a fourth aspect, the invention relates to a computer program product comprising code instructions for the execution (in particular on the data processing means 4, 5) of a method according to the first aspect of characterizing a part 2 in a system 1, as well as computer-readable storage means (memory 6) on which this computer program product is found.

Claims

Demands

1. Method for characterizing a part (2) in a system (1) comprising: • a chemical analysis device (3); • at least one robot (10a, 10b) equipped with actuated joints (1a, 11b) for manipulating • either a gripping device (12b) for grasping said part (2), • or said chemical analysis device (3); • data processing means (4, 5), • at least one detector (9); the process being characterized in that it includes the implementation by the data processing means (4, 5) of steps of: (c) Determination, as a function of data acquired by said detector (9), of a first trajectory of the robot(s) (10a, 10b) allowing to place opposite at least one target point of said part (2) and said chemical analysis device (3) in order to be able to carry out a chemical analysis of the material of said part (2) at the level of said target point;(d) Synchronized control of the robot(s) (10a, 10b) and said chemical analysis unit (3) so as to implement said first trajectory and obtain, during said first trajectory, chemical analysis data at each target point of said part (2) by means of said chemical analysis unit (3); (e) Processing of the chemical analysis data obtained so as to characterize said part (2).

2. A method according to claim 1, wherein the system (1) comprises a first robot (10a) provided with actuated joints (lia) for manipulating said chemical analysis device (3), said first trajectory being a displacement trajectory of at least said chemical analysis device (3) by the first robot (10a).

3. A method according to any one of claims 1 and 2, wherein the system (1) comprises a second robot (10b) equipped with actuated joints (11b) for manipulating a gripping member (12b) for grasping said part (2).

4. A method according to claim 3, wherein the part (2) is initially arranged in a first container (21), in particular in bulk, the method comprising prior steps of: a. Determining, based on data acquired by said detector (9), a second trajectory of the second robot (10b) enabling the grasping of said part (2) in the first container (21) with the grasping member (12b) of the second robot (10b) and moving it to a predetermined position, the first trajectory starting from said predetermined position; b. Controlling the second robot (10b) so as to implement said second trajectory.

5. Method according to claim 4, wherein the second trajectory further comprises scanning the surface of said part (2) by the detector (9).

6. A method according to any one of claims 3 to 5, further comprising steps of: (f) Determining, based on data acquired by said detector (9), a third trajectory of the second robot (10b) enabling the depositing of said part (2) into a second container (22) selected according to the result of the characterization of step (e), with the gripping member (12b) of the second robot (10b); (g) Controlling the second robot (10b) so as to implement said third trajectory.

7. A method according to any one of claims 3 to 6, wherein said first trajectory is a displacement trajectory of at least said part (2).

8. A method according to claims 2 and 7 in combination, wherein said first trajectory is a trajectory of simultaneous movement of the part (2) by the second robot (10b) and of said chemical analysis device (3) by the first robot (10a).

9. Method according to claim 7, wherein said chemical analysis device (3) is fixedly mounted on said system (1), said first trajectory being a trajectory of movement of the part (2) relative to said chemical analysis device (3) by the second robot (10b).

10. Method according to claim 9, wherein the system (1) includes a protective window (30) for said chemical analysis device (3).

11. A method according to any one of claims 1 to 10, wherein step (c) pre-includes a localization step (c0) on the part (2) of each target point as a function of at least one three-dimensional point cloud of the part (2), obtained from data acquired by the detector (9).

12. A method according to claim 11, wherein step (c0) includes determining the target point(s) according to the desired characterization.

13. A method according to any one of claims 1 to 12, wherein said detector (9) is a camera, in particular stereoscopic.

14. A method according to any one of claims 1 to 13, wherein the part (2) has a plurality of target points, the first trajectory allowing each target point of said part (2) and said chemical analysis device (3) to be placed sequentially opposite each target point of said part (2) in order to be able to carry out a chemical analysis of the material of said part (2) at each target point.

15. A method according to any one of claims 1 to 14, wherein a target point of said part (2) and said chemical analysis device (3) are opposite each other if the target point is aligned with an emission direction of an excitation source of said device (3); a distance between the target point and the excitation source of the device (3) is within a predefined range of operating distances; and an angle between said emission direction of the excitation source of the device (3) and the normal to the surface of the part (2) at said target point is within a predefined range of operating angles.

16. A method according to claims 14 and 15 in combination, wherein the first trajectory maintains said distance between the target point and the excitation source of the member (3) within the predefined range of operating distances, and said angle between said emission direction of the excitation source of the member (3) and the normal to the surface of the part (2) at said target point within the predefined range of operating angles, between two target points.

17. A method according to any one of claims 1 to 16, wherein said chemical analysis device (3) is an emission spectrometry device atomic, in particular of the type laser-induced plasma atomic emission spectrometry, LIBS.

18. A system (1) for characterizing a part (2), comprising: • a chemical analysis device (3); • at least one robot (10a, 10b) equipped with actuated joints (1a, 11b) for manipulating: • either a gripping device (12b) for grasping said part (2), • or said chemical analysis device (3); • data processing means (4, 5); • at least one detector (9); characterized in that the data processing means (4, 5) are configured to: - Determine, based on data acquired by said detector (9), a first trajectory of the robot(s) (10a, 10b) enabling the placement of at least one target point of said part (2) and said chemical analysis device (3) opposite each other in order to be able to carry out a chemical analysis of the material of said part (2) at said target point;- To control in a synchronized manner the robot(s) (10a, 10b) and said chemical analysis unit (3) so as to implement said first trajectory and obtain, during said first trajectory, chemical analysis data at each target point of said part (2) by means of said chemical analysis unit (3); - To process the chemical analysis data obtained so as to characterize said part (2);

19. Product computer program comprising code instructions for performing a method according to any one of claims 1 to 17 of characterizing a part (2) in a system (1), when said program is executed on a computer.

20. A computer-readable storage medium on which a computer program product is recorded, comprising code instructions for carrying out a process according to one of the claims 1 to 17 of characterization of a part (2) in a system (1).

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