Method for characterising a part by robotic chemical analysis

Abstract

The present invention relates to a method for characterising a part (2) in a system (1) comprising a chemical analysis member (3) and at least one robot (10a, 10b) for handling either a gripping member (12b) for grasping the part (2) or the chemical analysis member (3), the method being characterised in that it comprises implementing the steps of: (c) determining a first trajectory of the robot(s) (10a, 10b) allowing at least one target point of the part (2) and the chemical analysis member (3) to be placed opposite one another in order to be able to implement a chemical analysis of the material of the part (2) at the target point; (d) synchronously controlling the robot(s) (10a, 10b) and the chemical analysis member (3) so as to implement the first trajectory and to obtain, during the first trajectory, chemical analysis data at each target point of the part (2) by means of the chemical analysis member (3); (e) processing the chemical analysis data obtained so as to characterise the part (2).

Description

[0001] Description

[0002] Title of the invention: Method for characterizing a part by robotic chemical analysis.

[0003] GENERAL TECHNICAL FIELD

[0004] The present invention relates to the field of industrial process automation, particularly quality control by chemical analysis. More specifically, the invention relates to a method for characterizing a part within a system comprising a chemical analysis device, notably using atomic emission spectrometry, and at least one robot.

[0005] STATE OF THE ART

[0006] We know of techniques for chemical analysis of a sample by atomic emission spectroscopy, and in particular the LIBS technology "laser-induced breakdown spectroscopy" (in French laser-induced plasma atomic emission spectrometry or laser-induced plasma optical emission spectrometry).

[0007] This technique relies on the interaction of a pulsed laser with the material to be analyzed, locally vaporizing the matter and forming a plasma. Analysis of the plasma radiation's emission spectrum allows for the determination of the sample's elemental atomic composition.

[0008] 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 fast, so the applications are extremely numerous.

[0009] 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, recycling and waste management, and so on. The difficulty lies in handling the LIBS system, which at best weighs around ten kilograms, is dangerous, and must be used with precision.

[0010] 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, allowing for several hundred shots per day.

[0011] However, the performance of such robots is insufficient for widespread automatic use of the LIBS system in industry: if, for example, one wants to test all the parts coming off a production line, it is necessary to be able to carry out hundreds of thousands of shots per day.

[0012] The present invention improves the situation.

[0013] PRESENTATION OF THE INVENTION

[0014] The present invention therefore relates, in a first aspect, to a method for characterizing a part in a system comprising:

[0015] - a chemical analysis device;

[0016] - at least one robot equipped with actuated joints for the manipulation of either a gripping device allowing the said part to be grasped, or said chemical analysis device;

[0017] - data processing methods,

[0018] - at least one detector; the process being characterized in that it comprises the implementation by data processing means of steps of:

[0019] (c) Determination, based on data acquired by said detector, of a first trajectory of the robot(s) enabling the placement of at least one target point of said part and said chemical analysis device opposite each other in order to be able to carry out a chemical analysis of the material of said part at said target point; (d) Synchronized control of the robot(s) and said chemical analysis device so as to carry out 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;

[0020] (e) Processing of the chemical analysis data obtained in order to characterize said part.

[0021] According to advantageous and non-limiting characteristics:

[0022] 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.

[0023] The system includes a second robot equipped with actuated joints for manipulating a gripping organ to grasp the said part.

[0024] The part is initially placed in a first container, particularly in bulk,

[0025] The process includes preliminary steps such as:

[0026] (a) Determination, based on data acquired by said detector, of a second trajectory of the second robot enabling it to grasp said part in the first container with the grasping organ of the second robot and to move it to a predetermined position, the first trajectory starting from said predetermined position;

[0027] (b) Control of the second robot so as to implement said second trajectory.

[0028] The second trajectory also includes scanning the surface of said part with the detector.

[0029] The process also includes the following steps:

[0030] (f) Determination, based on data acquired by said detector, of a third trajectory of the second robot enabling the deposit of said part into a second container selected according to the result of the characterization of step (e), with the gripping organ of the second robot;

[0031] (g) Control of the second robot so as to implement said third trajectory.

[0032] The said first trajectory is a trajectory of displacement of at least the said part.

[0033] The said first trajectory is a trajectory of simultaneous movement of the part by the second robot and of the said chemical analysis organ by the first robot.

[0034] The said chemical analysis device is fixedly mounted on the said system, the said first trajectory being a trajectory of movement of the part relative to the said chemical analysis device by the second robot.

[0035] The system includes a protective window for said chemical analysis device.

[0036] 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.

[0037] Step (cO) includes the determination of the target point(s) according to the desired characterization.

[0038] The detector in question is a camera, specifically a stereoscopic one.

[0039] Part (2) presents a plurality of target points.

[0040] 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 implement a chemical analysis of the material of said part at each target point.

[0041] 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.

[0042] 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.

[0043] 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 within the predefined range of operating angles, between two target points.

[0044] The said chemical analysis instrument is an atomic emission spectrometry instrument, in particular of the laser-induced plasma atomic emission spectrometry type, LIBS.

[0045] According to a second aspect, the invention proposes a system for characterizing a part, comprising

[0046] - a chemical analysis device;

[0047] - at least one robot equipped with actuated joints for the manipulation of either a gripping device allowing the said part to be grasped, or said chemical analysis device;

[0048] - means of data processing;

[0049] - at least one detector; characterized in that the data processing means are configured to:

[0050] - 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;

[0051] - 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;

[0052] - Process the chemical analysis data obtained in order to characterize the said part.

[0053] According to a third and a fourth aspect, the invention proposes 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 recorded a computer program product comprising code instructions for executing a process according to the first aspect of characterizing a part in a system.

[0054] PRESENTATION OF THE FIGURES

[0055] 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:

[0056] [Fig. 1] Figure 1 is a general diagram of a system for implementing the process according to the invention;

[0057] [Fig. 2a] Figure 2a illustrates a first embodiment of the system for implementing the process according to the invention;

[0058] [Fig. 2b] Figure 2b illustrates a second embodiment of the system for implementing the process according to the invention;

[0059] [Fig. 3] Figure 3 is a flowchart representing the steps of an embodiment of the process according to the invention.

[0060] [Fig. 4] Figure 4 represents a particular case of so-called autofocus mode during the implementation of the method according to the invention.

[0061] DETAILED DESCRIPTION Architecture

[0062] With reference to Figure 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 multiple copies of the first part 2 in said first container 21), even though it is possible that the part 2 may already be arranged in an orderly fashion, 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.

[0063] Characterization of part 2 refers to the determination of its properties, such as material identification, qualitative or quantitative elemental analysis, chemical imaging, elemental distribution, etc. It should be noted that this characterization of part 2 can be global (i.e., encompassing the entire part) or local. In the latter case, the characterization advantageously includes a mapping component for part 2 (see below). In all cases, the result of the characterization can be a classification of the part, particularly among several predefined classes, including acceptance and rejection classes.

[0064] For example, in an industrial process, particularly in metallurgy, one may have a large number of freshly manufactured copies of said part 2, and said characterization is a non-destructive quality control, allowing verification that each copy has an acceptable chemical composition.

[0065] One or more secondary containers can be used to receive the assembled parts, advantageously one secondary container per possible class (for example, one for accepted part 2 and one for rejected part 2 in the case of a binary classification system such as quality control). The first and second containers (or receptacles) 21, 22 are typically crates, opened to allow access to the parts inside and their individual removal.

[0066] It is understood that the process may include, where appropriate, an inherent component of debulking (of part 2), in addition to characterization, the two being able to be done simultaneously, without going through a phase of repositioning the debulked parts.

[0067] System 1 for implementing the present process further includes a chemical analysis device 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.

[0068] Preferably, this is a local chemical analysis, in other words a spot analysis, i.e., applied to a limited area of ​​part 2 around a target point, typically less than 1 mm 2 and advantageously less than 100pm 2 or even less than 10pm 2 .

[0069] Similarly, each chemical analysis is brief (in particular less than one second, advantageously less than one millisecond, advantageously less than one microsecond) or even ultra-brief (potentially less than one nanosecond in the case of a LIBS, see below).

[0070] The idea is indeed to be able to characterize the part at a very fine level, if necessary at a plurality of target points. "Global" chemical analyses, in which a large surface could be analyzed at once, or continuous analyses, such as Raman spectroscopy, in which the part is scanned, are excluded due to their imprecision.

[0071] 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).

[0072] In the preferred embodiment of a LIBS, the excitation source is a pulsed laser (i.e., with an ultrashort pulse, in particular 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, the component 3 thus preferentially has a range of valid operating distances, or even an optimal operating distance, corresponding in particular 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, we will preferentially choose a component with an optimal operating range of a few centimeters, given the usual amplitudes and precision of robotic arms 10a and 10b.

[0073] The energy per pulse is very low, less than 1 joule, but given its ultra-short duration, colossal powers are mathematically achieved.

[0074] This process exceeds the "ablation threshold" of the material in part 2, causing it to vaporize at the laser's point of impact. The generated gas absorbs some of the laser radiation. It heats up and becomes partially ionized, immediately triggering the formation of a "micro" plasma containing electrons, atoms, and ions in an excited state. Thus, the pulse simultaneously generates the plasma and optically excites the atomic and ionic species it contains. This then emits radiation. The temperature of this microplasma can reach tens of thousands of degrees Celsius.

[0075] Excited atoms and ions, upon de-exciting, emit a spectrum consisting of atomic lines, the wavelength of which allows the identification of the elements present.

[0076] The position of the spectral lines indicates the elements present in the sample, and their intensity is related to the concentration of those elements. Thus, it is possible to identify and quantify the elements present in the material at the point of impact. Advantageously, system 1 can include another component for analyzing part 2, particularly when coupled with component 3, such as a profilometer, an acoustic sensor, etc. The aim is to combine chemical analysis with another analysis, particularly mechanical or physical, of part 2.

[0077] System 1 further includes data processing means 4, 5 and at least one robot 10a, 10b (potentially two). In the example in Figure 1, there are two robots designated as first robot 10a and second robot 10b. In Figure 2a, there is only first robot 10a, and in Figure 2b, there is only second robot 10b. Note that second robot 10b can play the role of first robot 10a; all possible configurations will be explained later.

[0078] 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 Figure 1, we have on one side first data processing means 4 present locally and directly connected to the robots 10a, 10b, and to the chemical analysis unit 3, advantageously configured to control the robots 10a, 10b, and the chemical analysis unit 3; and on the other side 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.

[0079] These means, 4 and 5, are, for example, the data processing means of two computers, such as a laptop and a server. It should be understood that means 4 and 5 can be considered equivalent.

[0080] The system 1 also typically includes data storage means 6 (a 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 having in particular a platform for placing the containers 21, 22 and on which the interface 7 can be mounted.

[0081] System 1 further includes at least one detector 9, i.e., a "scanner," for observing room 2 and, in particular, for providing data to recognize and locate it, also connected to the processing means 4, 5. Any radiation sensor (especially optical) providing data that allows the reconstruction of 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 using 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 occultations.

[0082] In all cases, detector 9 is positioned to view parts 2, either statically (fixed) or mounted on one of the robots 10a or 10b (as shown in Figure 1), and in all cases is capable of acquiring a three-dimensional point cloud, and generally a two-dimensional image. It should be noted that detector 9 may be an optical sensor that is identical to the optical sensor of the chemical analysis unit 3.

[0083] Robot(s)

[0084] The system includes at least one robot 10a, 10b equipped with actuated joints 11a, 11b for the manipulation of either a grasping organ 12b for grasping said part 2, or said chemical analysis organ 3.

[0085] We therefore have two alternatives, and we designate:

[0086] - first robot 10a the robot equipped with actuated joints 11 a for the manipulation of said chemical analysis organ 3; - second robot 10b the robot equipped with actuated joints 11 b for the manipulation of a gripping organ 12b allowing to grasp said part 2.

[0087] In other words, the first robot 10a is directly equipped with said chemical analysis unit 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 Figure 2a which will be described later), or that the latter itself has a grasping mechanism allowing it to grasp said chemical analysis unit 3 (not shown).

[0088] Several embodiments of the invention are possible with the first and / or second robot 10, 10b:

[0089] - according to a first embodiment, corresponding to figure 2a, we only have the first robot 10a,

[0090] - according to a second embodiment, corresponding to figure 2b, we only have the second robot 10b,

[0091] - according to a third embodiment, not shown, we have both the first robot 10a and the second robot 10b,

[0092] - 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.

[0093] It should be noted that in the case of the third embodiment of two robots 10a, 10b, the latter are "distinct", in that they are manipulated independently so that the first robot 10a can move the chemical analysis organ 3 relative to the second robot 10b and that the second robot 10b can hold and move the part 2 relative to the first robot 10a, i.e. that they have different actuated joints, but they can "be part" of the same large robot. A robot such as the first or second robot is generally called a "robot arm" because the actuated joints 11a, 11b, or "joints" allow it to change position and thus move a part 2 / organ 3. In the example of figures 2a, 2b, the robot 10a, 10b is of the Staübli RX160 type with 6 actuated joints 11a, 11b, but any other architecture will be possible, including Cartesian robots, because the notion of actuated joints will be interpreted broadly.

[0094] The grasping 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 work together to move this grasping 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 11a work together to move this chemical analysis member 3.

[0095] 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.

[0096] For convenience, in the following description, the "position" of a robot 10a, 10b will be defined as the value of the position vector of each joint, denoted [j1, j2, j3, j-4, 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 / chemical analysis 3 to be correlated with a position [j1, j2, j3, j-4, j5, j6] of the robot 10a, 10b.

[0097] 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 suffered 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.

[0098] As explained, the present process may involve the unloading of part 2 by the second robot 10b. Process

[0099] We will define the general framework of the process and the principle of the invention, and then we will describe the various embodiments mentioned.

[0100] 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.

[0101] Alternatively, with reference to Figure 3, the process may begin with optional steps of (a) determining a second trajectory for the second robot 10b to grasp said part 2 in the first container 21 and move it to said waiting position; and (b) controlling the second robot 10b to implement said second trajectory.

[0102] The second trajectory of the second robot 10b advantageously comprises successively:

[0103] - 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

[0104] - An approach phase, in which the first robot 10a moves, holding part 2, from the gripping position to the waiting position.

[0105] Step (b) then includes, where appropriate (if the waiting position corresponds to a position in which part 2 is placed on a support, preferably, if the first robot 10a is confused with the second robot 10b), the placement of said part 2 by the gripping member 11a of the first robot 10a.

[0106] 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 according to at least a 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 by known means, and / or a scan of the environment).

[0107] - 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);

[0108] - The execution of a trajectory is done with an appropriate controller of the actuated joints 11 b of the second robot 10b.

[0109] When the data acquired by detector 9 includes at least one image, step (a) advantageously comprises segmenting that image so as to restrict the point cloud to part 2. The idea is to facilitate the subsequent steps by discarding parts of the point cloud representing other parts. This can be achieved using a neural network trained for this purpose, for example, Mask-RCNN or one of its derivatives.

[0110] Note that the 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 allows the acquisition of data from which a three-dimensional point cloud representing the part as completely as possible can be constructed. To rephrase, the second robot 10b can move in such a way that detector 9 and part 2 move relative to each other:

[0111] - 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;

[0112] - 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 of scanning. The second trajectory can therefore include the scanning phase when part 2 is not held by the component 12, either before (i.e., in the container 21 - if possible) or after the movement to the waiting position.

[0113] 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.

[0114] Next, the method includes main steps (c) determining a first trajectory of the robot(s) 10a, 10b allowing at least one target point of said part 2 and said chemical analysis device 3 to be placed 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; and (d) synchronously controlling 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.By commanding said chemical analysis unit 3 to obtain chemical analysis data at each target point of said part 2 by means of said chemical analysis unit 3, we mean activating, for each target point of said part 2, said chemical analysis unit 3 when it is opposite the target point so as to obtain said chemical analysis data at the target point. Thus, step (d) is a synchronized command step of the robot(s) 10a, 10b and said chemical analysis unit 3 so as to implement said first trajectory and activate, during said first trajectory, said chemical analysis unit 3 at each target point of said part 2 to obtain chemical analysis data at each target point of said part 2.

[0115] In other words, instead of specifically "aiming" at the target points one by one with a laborious positioning, adjustment, firing, positioning, adjustment, firing, etc. strategy, a quality trajectory passing through all firing positions is directly determined, a trajectory executed agnostically by robots 10a, 10b without regard to organ 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.

[0116] Activation of the chemical analysis unit 3 generally refers to the activation of its excitation source, i.e., firing at a target point, its optical sensor being able to operate continuously passively. Indeed, it is this firing that, in practice, triggers the excitation of the material in part 2 at the target point and thus the production of chemical analysis data relating to the target point.

[0117] This activation is brief (and not continuous over the entire trajectory). It should be noted that the chemical analysis is a point analysis, and therefore the first trajectory precisely positions a target point on part 2 and the chemical analysis device 3 in order to perform a specific and localized chemical analysis of the material of part 2 at the target point, and not extended over the entire surface of part 2.

[0118] By "placing opposite" (or placing facing each other), we mean positioning the component 3 so that it is correctly aligned with the part 2 to perform the chemical analysis. It is important to remember that component 3 is primarily an optical instrument, so it must "see" the target point to operate on it, and the analyzed surface is generally very small. 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:

[0119] - 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;

[0120] - a 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 a focusing depth of field of the laser in the case of a LIBS, for example a range with 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 within said range;

[0121] - 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.

[0122] Thus, it is sufficient to generate an initial trajectory which respects, for each of the target points, the aforementioned criteria.

[0123] It is recalled that the first trajectory may involve the first and / or the second robot 10a, 10b, i.e. part 2 and / or component 3 can in practice move, since only their relative positions matter.

[0124] In the case of multiple target points, the first trajectory allows each target point of part 2 and the chemical analysis device 3 to be sequentially positioned opposite each other, in order to perform an independent chemical analysis of the material of 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 critical, and therefore there are a large number of possible trajectories, although the shortest possible trajectory will be preferred. It is reiterated that the chemical analysis of the material of part 2 at each target point is performed independently; that is, there is a distinct activation of the chemical analysis device 3 at each target point (and therefore a subsequent deactivation).In other words, organ 3 (and in practice its source of excitation) is switched on briefly at the passage of each point and switched off during the rest of the first trajectory (between the target points).

[0125] Again, the first trajectory must respect, for each of the points of said plurality of target points, the aforementioned criteria.

[0126] In an optimal embodiment, known as autofocus or "constant focusing" (see Figure 4), the initial trajectory continuously maintains (at least during a main phase in which it passes directly over each target point; i.e., this is always true between two target points, although it is understood that the instrument 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., it keeps the distance between the instrument 3 and the part 2 and the approach angle constant or nearly so. This guarantees maximum and consistent measurement quality.

[0127] 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 component 3 in which it is opposite, and generate the first trajectory accordingly by considering these positions as passage points and respecting any criteria.

[0128] The first trajectory can thus be determined by a planning algorithm (in the same way as the potential second trajectory), knowing the required passage position(s) defined by component 3 and the 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.

[0129] Remember that part 2 can move relative to part 3 and / or part 3 can move relative to part 2, it will just be a matter of defining a suitable relative reference frame.

[0130] Furthermore, step (c) advantageously includes, in the same way as in step (a), a preliminary localization step (cO) 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 detector 9. There may be one or more target points, possibly predetermined (i.e. of given coordinates in a reference frame of the part), or corresponding to points of interest of part 2 (for example, "suspect" points which would have an unusual appearance, or sensitive areas such as welds which we wish to check), or even chosen dynamically according to the desired characterization.

[0131] 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.

[0132] For example, this selection can 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 can be pre-positioned in the model). Thus, one or more models of different parts 2 can be stored by the data storage means 6, with step (c0) comprising the recognition of 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 points based on said model. Alternatively, the data processing means 4, 5 can implement 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.Note that the selection can remain totally random, especially in a case of quality control, but we will have a precise shot of organ 3 on this randomly selected point, and not a random shot of organ 3, which could be dangerous and in practice would be of little use.

[0133] Alternatively, one might wish to map part 2 completely, or at least a portion of it, in order to perform a comprehensive characterization, particularly if part 2 is large. In this case, a set of target points covering all or part of part 2 is selected, 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 first high target point density can be applied to a critical area of ​​part 2, and a second low target point density to the remainder (corresponding to a second portion of part 2).

[0134] It is noted that the autofocus mode is particularly suitable in the case of mapping with a large number of points.

[0135] 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.

[0136] If this has not already taken place (in particular in step (a), during the second trajectory), step (cO) may include scanning all or part of the surface of part 2 with detector 9.

[0137] Step (d) includes 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);

[0138] - 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.

[0139] The only requirement is that the commands be correctly synchronized, which isn't 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 planned; robot 10, 10b, doesn't concern itself with component 3. The activations of component 3 are simply added afterward in a coordinated manner.

[0140] Note that the first trajectory can be slowed down or even pause for a predetermined amount of time each time the component 3 approaches a target point, while the chemical analysis is performed. This provides some tolerance for command synchronization. However, the preferred method is for the first trajectory to be continuous and at a nearly constant speed, i.e., the robots 10a and 10b do not stop, and the activations occur at precisely the right moment, thus significantly accelerating the process. It is worth recalling that the activations are brief, even ultra-brief, so the movement of the robot 10a and 10b during the activation time can be negligible (during a pulse on the order of a nanosecond, the robot's movement is on the order of a nanometer), hence the possibility for the first trajectory to remain continuous.Furthermore, it is recalled that organ 3 is deactivated between activations at each target point, that is, during most of the first trajectory.

[0141] Preferably, step (d) also includes the use of 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, as 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.

[0142] Thanks to these steps (c) and (d), the present process 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.

[0143] Note that step (d) may, if system 1 further includes another measuring device, have its control also synchronized with 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.

[0144] This is automatic or almost automatic if the said other measuring device is coupled with device 3.

[0145] The process then includes a step (e) of processing the chemical analysis data obtained (for each target point) in order to characterize said part 2. If there are any other measurement data, they can be processed together.

[0146] This step, as explained, can be implemented in any known way (material identification, qualitative or quantitative elemental analysis, chemical imaging, element distribution), and where appropriate include a classification of part 2

[0147] Step (e) may alternatively or in addition include generating a map of all or part of the component in the case of distributed target points. For example, it is possible to define which parts of component 2 are made of which material, whether there is contamination, etc. This is particularly useful in the nuclear industry, especially if component 2 is an irradiated component or a component resulting from dismantling.

[0148] In optional final steps (f) and (g) (the characterized part could simply be dropped by the second robot 10b, or retrieved by an 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 the 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.

[0149] Preferably, the said characterization is, as explained, a classification, and we can have a second container 22 per predefined class, and we place each piece 2 into the second container 22 which corresponds to the class which has been determined for it.

[0150] These steps can again be implemented similarly to steps (a) and (b).

[0151] First embodiment - embedded mode

[0152] According to Figure 2a, only the first robot 10a can be used to manipulate the chemical analysis unit 3, the first trajectory being a trajectory of movement of at least the chemical analysis unit 3 by the first robot 10a, or even a trajectory of movement of only the 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 leave its optical sensor (spectrometer) fixed.

[0153] 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 11a of robot 10a, hence the term "embedded mode." Part 2, on the other hand, 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).

[0154] This method of embodiment is particularly suited to characterizing parts 2 at the output of a production line.

[0155] Second embodiment – ​​fixed-station mode

[0156] According to figure 2b, we can have only the second robot 10b, for the manipulation of a gripping organ 12b allowing to grasp said part 2, said first trajectory being a trajectory of displacement of at least said part 2, with respect to said chemical analysis organ 3, and even of displacement of only said part 2 by the second robot 10b.

[0157] The component 3 is fixedly mounted on said system 1. It is therefore understood that the second robot 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 from a container 30 (Figure 2b shows a platform acting as a container on which a plurality of interlocking parts 2 are arranged).

[0158] Preferably, system 1 includes a protective window 30 for said chemical analysis organ 3. In other words, organ 3, or at least its excitation source, is positioned behind this window 30, while the first robot 10a, and therefore 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 organ 3 protected.

[0159] This method of 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 organs 3. For example, it can be used in the dismantling of nuclear installations.

[0160] Third embodiment - double mode

[0161] In this mode, we have the two robots 10a, 10b as in figure 1.

[0162] 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.

[0163] The first trajectory is thus:

[0164] - either a simultaneous movement trajectory 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;

[0165] - either a trajectory only of said chemical analysis 3 (by the first robot 10a), with the second robot 10a carrying out a second and / or a third trajectory as defined previously (steps (b) and (g)).

[0166] Indeed, this third mode is particularly suitable for unpacking with the placement of parts into 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 the step (e).

[0167] This embodiment is particularly suited to a classification of parts received in bulk, the parts being automatically unpacked, sorted and checked (in terms of quality)

[0168] Fourth embodiment - hybrid mode In this mode (not shown), a single robot plays alternately the role of first and second robot 10a, 10b.

[0169] This mode offers essentially the same effects as the third mode, but at a lower cost because only one robot is needed. However, the process is slower.

[0170] To do this, the robot 10a, 10b has a gripping organ 12b allowing it to grasp either the said part 2, or the organ 3.

[0171] 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).

[0172] System

[0173] According to a second aspect, the invention relates to system 1 for implementing the process according to the first aspect.

[0174] The system includes

[0175] - a chemical analysis device 3, in particular of the LIBS type;

[0176] - at least one robot 10a, 10b, and advantageously two, equipped with actuated joints 11a, 11b for the manipulation of either a gripping organ 12b allowing the grasping of said part 2 (called second robot 10b), or of said chemical analysis organ 3 (called first robot 10a);

[0177] - data processing means 4, 5 (and possibly a memory 7 and an interface 8);

[0178] - at least one detector 9, such as a stereoscopic camera. The data processing means 4 are configured to:

[0179] - 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;

[0180] - Optionally, order the second robot 10b so as to implement said second trajectory;

[0181] - 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;

[0182] - 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;

[0183] - Process the chemical analysis data obtained in order to characterize said part 2;

[0184] - 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;

[0185] - Optionally, order the second robot 10b so as to implement said third trajectory.

[0186] computer program product

[0187] 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 (11a, 11b) for the manipulation of either a gripping organ (12b) allowing the grasping of said part (2), or of said chemical analysis organ (3); - means of data processing (4, 5), - at least one detector (9); the process being characterized in that it comprises the implementation by data processing means (4, 5) of steps of: (c) Determination, based on 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) equipped with actuated joints (11a) for manipulating said chemical analysis device (3), said first trajectory being a trajectory of movement of at least said chemical analysis organ (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 placed in a first container (21), in particular in bulk, the method comprising preliminary steps of: (a) Determination, based on data acquired by said detector (9), of a second trajectory of the second robot (10b) enabling the grasping of said part (2) in the first container (21) with the grasping organ (12b) of the second robot (10b) and moving it to a predetermined position, the first trajectory starting from said predetermined position; (b) Control of 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 the steps of: (f) Determination, based on data acquired by said detector (9), of a third trajectory of the second robot (10b) allowing to deposit said part (2) in 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); (g) Control of 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 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) comprises a viewing window (30) for protecting said chemical analysis device (3).

11. Method according to any one of claims 1 to 10, wherein step (c) includes prior to 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. Method according to claim 11, wherein step (c0) comprises the determination of the target point(s) according to the desired characterization.

13. 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 atomic emission spectrometry device, in particular of the laser-induced plasma atomic emission spectrometry, LIBS type.

18. System (1) for characterizing a part (2), comprising - a chemical analysis device (3); - at least one robot (10a, 10b) equipped with actuated joints (11a, 11b) for manipulation either a grasping device (12b) allowing the said part (2) to be grasped, or said chemical analysis device (3); - means of data processing (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) 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 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); - Process the chemical analysis data obtained in order to characterize said part (2) 19. Product computer program comprising code instructions for the execution of 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. Computer-readable storage means on which is recorded a computer program product comprising code instructions for the execution of a process according to any one of claims 1 to 17 of characterizing a part (2) in a system (1).

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