Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16P—SAFETY DEVICES IN GENERAL; SAFETY DEVICES FOR PRESSES
  • F16P3/00—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body
  • F16P3/12—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine
  • F16P3/14—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine the means being photocells or other devices sensitive without mechanical contact
  • F16P3/144—Safety devices acting in conjunction with the control or operation of a machine; Control arrangements requiring the simultaneous use of two or more parts of the body with means, e.g. feelers, which in case of the presence of a body part of a person in or near the danger zone influence the control or operation of the machine the means being photocells or other devices sensitive without mechanical contact using light grids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
  • B25J19/02—Sensing devices
  • B25J19/021—Optical sensing devices
  • B25J19/022—Optical sensing devices using lasers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
  • B25J19/06—Safety devices

Definitions

• the invention relates to a method and a device adapted to a robot for detecting an intrusion into the environment of the robot.
• the invention is more particularly, but not exclusively, intended for a robot, or "cobot", operating in a congested medium in which other robots or human operators intervene, in particular in the field of structural assembly, installation of systems or handling in the automotive, aeronautical or naval industries.
• a robot capable of cooperating with an operator, machine or human is commonly referred to as a "cobot".
• cobots In the context of an automated production system, several cobots are likely to intervene jointly with human operators, or in the immediate vicinity of said operators.
• the intervention of an operator, in particular a human operator, in the vicinity of a robot is a complex situation given the danger represented by the moving robot, which is programmed to perform specific tasks, but must also ensure the safety of the operator who enters his workspace, as well as his own safety.
• the problem is similar for coordinating multiple robots whose workspaces include common volumes, to avoid collisions.
• a robot capable of working in co-activity comprises several safety devices, used alone or in combination.
• a cobot is equipped with sensors capable of recognizing its environment and is provided with a program enabling it to decide on the possible actions as a function of this environment.
• this environment is recognized, on the one hand, from a map of the place of intervention, recorded in the programming means of the robot, and on the other hand, by means of location, by example beacons, which allow the robot to know its position in said map and finally by sensors carried by the robot itself or in the immediate vicinity thereof, which sensors provide him with a concentric image of his environment.
• perception volume The work volume perceived by the robot and in which this robot is able to evolve safely, both for itself and vis-à-vis other operators, humans or robots. Said perception volume completely or partially encompasses the robot and makes it possible to detect an intrusion into the environment of the robot, that is to say the presence in this environment of an unusual object or more generally not intended.
• the means for detecting an intrusion into the perception space of the robot means based according to the prior art on fixed sensors and sensors embedded by the robot, and informing it of its concentric working environment, do not allow to obtain a global vision of a changing environment. Consequently, there are zones, called shadow zones, in which the fixed sensors where the onboard sensors of the robot do not make it possible to apprehend the environment and thus an intrusion in this environment. These shadows reduce the volume of perception of the robot and consequently its useful volume of work.
• the cobot comprises means for detecting a collision, that is to say a direct, unplanned contact with one of its members.
• These means are, for example, force sensors on its various axes. Such detection causes a safety stop of the robot when the force measured on one of these sensors exceeds a threshold value. Once in safe stop, the robot must be reset to resume normal operation.
• the robot evolves according to a so-called security speed.
• This safety speed is sufficiently reduced to both allow a possible operator to easily anticipate the movements of the robot and thus avoid the collision, and on the other hand, not to hurt the operator if ever such a collision happened despite everything.
• US 2014/0238153 discloses a sensor, similar to an artificial skin, formed on the basis of a hyperelastic polymer inserting a conductive liquid and covering a robotic actuator, thereby allowing said robot to detect low pressure contacts on said skin.
• This device makes it possible to have a contact sensor covering all the members of the robot, and to decouple the detection of a collision of the forces produced by the axis motors.
• the documents US4694231, JP2004034251 or CN202572408 describe other examples of artificial skin covering all or part of the robot and able to detect contacts on said skin.
• the invention aims to solve the disadvantages of the prior art and for this purpose concerns a device adapted to be fixed on a mobile member of a robot or a manipulator and intended for the protection of said mobile member, by the detection of an intrusion into the environment of said device according to the invention, and consequently in the environment of said robot or manipulator, the device comprising:
• a laser source generating an incident laser beam, spaced from said movable member and extending substantially parallel to said movable member;
• a sensor on the path of said incident beam capable of delivering information according to its illumination by a laser beam.
• any intrusion into the environment of the robot interfering with the laser beam is detected by the sensor before the intrusive object is in contact with the moving member.
• Said laser beam follows the moving member in its evolutions and therefore this detection device does not include a shadow zone.
• the sensor is positioned in the path of a reflected beam of said incident beam.
• the device of the invention comprises a plurality of laser sources and a plurality of sensors, the assembly being configured to surround all or part of said mobile member.
• the series of elementary devices creates a real virtual skin around the part of the member, to detect any intrusion on said part before a collision.
• the device according to the invention is intended to equip a robot or a manipulator comprising at least two mobile members with respect to each other, the laser source being adapted to be connected to a first mobile member, and the device comprises a flexible optical conduit intended to be positioned between each mobile member, which flexible conduit is able to extend between two mobile members and capable of redirecting the laser beam from one member to another during their relative movements.
• a single elementary device, associated with optical conduits can protect all members of a robot, including polyarticulate.
• the device which is the subject of the invention comprises:
• a target whether materialized by a particular optical device or by the surface of an object, makes it possible, in cooperation with the sensor, to generate information relating to the incident beam continuity between the source and the object. target.
• the senor measures the distance between the target and the laser source.
• This embodiment makes it possible, among other things, to detect a potential collision beyond the members of the robot, it also makes it possible to implement different behaviors as a function of the distance actually measured and consequently of the nature of the potential collision.
• This embodiment also makes it possible to detect other types of abnormal operation, without the laser beam being interrupted by a intrusive object, such as a high vibration level or an abnormal configuration of the component carrying the target.
• the distance is measured by reflection on the target.
• the target is a surface located at a defined distance from the laser source and illuminated by said source.
• the target is not necessarily permanently materialized and, according to one example, is constituted by a surface of the intrusive object itself.
• the target is a photoelectric detector.
• the target and the sensor are the same elements.
• This variant embodiment is the simplest of implementation and detects in practice any interruption of the incident laser beam.
• the device comprises two photoelectric detectors, a divider at the output of the laser source, and a frequency generator for modulating the power of the laser beam, one of the photoelectric detectors being illuminated. by the part of the beam thus divided.
• This embodiment makes it possible to detect a simple cut of the laser beam, but also by phase difference between the signals received on the two photoelectric detectors to measure the relative distance between said photoelectric detectors, without the need to capture the reflected beam.
• the laser beam is a substantially plane laser curtain whose width covers all or part of the width of the member.
• This embodiment makes it possible to cover a large area around the robot or manipulator member with a reduced number of laser sources.
• the optical conduit located between two of the members of a robot or a manipulator comprises an optical fiber helically wound in said conduit.
• This embodiment allows the optical path to follow significant links between the limbs without risk of degradation of the optical fiber.
• the invention also relates to a method for detecting an intrusion into the environment of a robot or a manipulator implementing a device able to measure the distance between the target and the laser source, which method comprises the steps consists in :
• step iv. if the distance measured in step iii) is outside the tolerance acquired in step ii), place the robot or the manipulator in safety operation.
• the nominal distance obtained in step i) or the tolerance obtained in step ii) comprise an infinite distance. This embodiment makes it possible to detect an intrusion into an extended area of the robot environment in which no object is supposed to be in nominal operating conditions.
• the values obtained during steps i) and ii) are updated according to the operation performed by the robot or the manipulator.
• the method which is the subject of the invention comprises a step consisting of:
• step ii) being a function of the speed of variation of the distance measured in step v).
• the invention also relates to a robot or a manipulator which robot or the manipulator comprises at least two movable members with respect to the other, and a device as described previously in the context of the present invention, the laser source being linked to a first mobile member, and the device comprises between each mobile member a flexible optical conduit, and the robot and the device being such that each flexible conduit that extends between two members is adapted to redirect the laser beam from one member to another during their relative movements.
• a single elementary device, associated with optical conduits can protect all members of a robot, including polyarticulate. With such a robot, or cobot, the intrusion is detected before the intrusive object has reached the structure of the robot.
• the robot or manipulator according to the invention advantageously comprises several protection devices, each device being produced according to any one of the preceding embodiments.
• the laser beams of the plurality of devices protecting the robot are arranged in layers in a direction substantially perpendicular to the members of said robot or manipulator.
• FIG 1 is a schematic side view of a polyarticulate robot implementing several embodiments of the device object of the invention
• FIG. 2 shows, according to a schematic side view, a polyarticulated robot implementing other embodiments of the device that is the subject of the invention
• FIG. 3 is a diagrammatic sectional view of an exemplary embodiment of an optical conduit between two articulated members of a robot implementing the device that is the subject of the invention
• FIG. 4 shows a block diagram of an exemplary embodiment of the method that is the subject of the invention.
• the device of the invention is applied to a robot (100) polyarticulate, in the form of a manipulator arm anthropomorphic, comprising a plurality of members (01, 102, 03) articulated together in a series architecture, without this configuration example is limiting.
• Said robot is for example placed on a base (105) pivoting, said base being, according to exemplary embodiments, linked to a fixed inking or comprises means for moving the robot such as wheels or caterpillars.
• the robot comprises at the end of the articulated arm an effector (104), which effector is, for example, a gripper, a rivet clamp, a welding torch, a machining device, a gluing gun, a means of marking or measurement, or a combination of these means without these examples being limiting.
• the device according to the invention comprises one or more laser sources (1 10) connected to the base (105) and each emitting an incident laser beam (121, 122) substantially parallel to the first member (101) bound at the base (105) of the robot.
• said sources consist of laser diodes with a power of between 0.5 mW and 5 mW.
• the laser sources are not directly linked to the robot, and an optical device, for example an optical fiber, makes it possible to route the incident beam to the robot.
• the incident laser beam (121, 122) when each link (106, 107) passes between two members, the incident laser beam (121, 122) is reoriented by optical ducts having a certain flexibility so as to follow the deflections of said links.
• the incident laser beams (121, 122) generated by the sources (1 10) extend substantially parallel to the members (101, 102, 103) over all or part of the length of the robot.
• the incident laser beams terminate at their ends on targets (140).
• the device of the invention comprises a single laser source, which is divided into several beams by a suitable optical device, so as to generate several laser beams surrounding the robot member.
• a computing device (190) including a program for intrusion processing, communicates with the control bay (191) of the robot, controls the emission conditions of the laser sources (110) and retrieves information from the sensors illuminated by the laser beams.
• the targets (140) are photoelectric detectors and deliver an electrical signal when illuminated by a laser beam (121, 122).
• the target (140) is no longer illuminated, and no longer delivers this electrical signal, even before the intrusive object has reached a member of the robot.
• Detecting the loss of the signal emitted by one of the targets (140) triggers a procedure to place the robot in a security configuration.
• said security configuration corresponds to an emergency stop with the need to reset the robot, or more simply to stop the robot in its position in a gravity compensation situation, or the robot switches to reduced speed. , without these examples being limiting.
• the intrusion is detected before the intrusive object has reached the structure of the robot, so it is not a collision in the strict sense but a potential collision which is treated by appropriate measures.
• the plurality of laser beams extending around the members of the robot constitutes a kind of "virtual skin".
• the position of the intrusion is detected by the interruption of one or more beams and the setting security configuration comprises a movement order, preferably at a reduced speed robot, which movement tends to move the robot away from the potential contact.
• each member (101, 102, 103) comprises a plurality of laser sources and a plurality of targets linked to said member.
• the optical conduits are not necessary.
• the device according to the invention comprises, on the path of the one (122), incident laser beams surrounding the members of the robot, a divider (150) orienting a portion (23) of said beam towards a photoelectric detector (141).
• a divider 150
• the time required for the light generated in said beam to reach the two targets (141, 140) it lights is different, depending on the length of the optical path leading to each of these targets.
• by modulating the power of the laser generated by the source for example according to a sinusoidal function, this difference in optical path length results in a phase shift of the signals recovered on each of the detectors (140, 141). photoelectric illuminated by said beam (122) power modulated.
• the corresponding laser source (110) is equipped with a frequency generator able to modulate its transmission power.
• the modulation frequency is between 100 kHz and 10 MHz, adapted to the length of the optical paths in the presence and the targeted type of detection.
• the length of the optical path to the target (141) illuminated by the divided portion (123) of the beam being known, as well as the speed of light, the measurement of this phase shift makes it possible to determine the distance between the laser source ( 110) and the target (140) at the end of the laser beam (122).
• any interruption of the laser beam (122) by an intrusive object is detected by the interruption of the illumination of the target (140), but also, the measurement of the distance of said target relative to the Laser source offers other control possibilities.
• the distance between the laser source (1 0) and the target (140) illuminated by the end of the laser beam (122) is a function of the type of effector (104) used, within a defined tolerance.
• This distance value is for example defined in the robot command and control program, depending on the effector used for the task to be performed. If the distance actually measured does not correspond to the indicated value, that is to say that the measured value is out of tolerance, then it is possible that the effector installed on the robot does not correspond to the effector provided for in the control program, or even the installation of the effector on the robot is defective, potentially generating situations of collisions, so that the robot is placed in security configuration by generating, for example, an alert.
• This same device also makes it possible to measure the amplitude, the speed or the vibration acceleration of the effector (104) on which is disposed the target (140) illuminated by the end of the beam (122) previously divided.
• the intensity of vibration of the effector exceeds an authorized value, corresponding for example to a machining using a tool worn or a defect of support of the part machined by the robot, then the operation is stopped, the robot is put in security configuration and an alarm is generated.
• each robot member is individually equipped with the device described above and comprises for this purpose a laser source, a divider, a photoelectric detector illuminated by the divided beam and another photoelectric detector illuminated by the laser beam at the end of the member opposite to the laser source.
• the optical conduits are not necessary.
• the laser source (210) comprises a sensor type photoelectric detector.
• the photoelectric detector is capable of being illuminated by a reflected beam (223, 224) of the incident beam.
• this device uses a target (240) which has no sensor and is constituted by a reflective patch, or simply by the surface of the end of the member (104) if the latter is sufficiently reflective.
• the laser source (210) emits laser pulses of a definite duration, which propagate along an incident beam (221) to the target (240) via the optical conduits (230) according to the embodiment.
• the incident beam (221) is reflected on the target (240) into a reflected beam (223) which propagates, where appropriate, through the optical paths (230) to the laser source sensor.
• the time separating the emission of the incident beam (221) from the reception of the reflected beam makes it possible to measure the distance of the optical path traveled, proportional to the distance separating the source (210) from the the target (240).
• the introduction of an intrusive object intersecting the incident beam (221) or the reflected beam (223) produces an anomaly in the measurement of this distance and thus makes it possible to detect a collision risk and then act accordingly.
• This embodiment has the same advantages as that integrating a divider, by making it possible to measure the distance of the target (240), or its vibration conditions, and to compare these measurements with nominal data with a tolerance corresponding to the operating conditions.
• the robot does not include a specific target and the incident beam (222) points in a vacuum.
• the target is then constituted by the surface of an object (200) outside the robot.
• the incident beam (222) points in front of the effector (104) of the robot and the said incident beam is reflected on the surface of an object (200) lying in the direction pointing said incident beam.
• the measurement of the flight time of the laser pulse between the incident beam (222) and the reflected beam (224) by the surface of the object (200) makes it possible to determine the distance of said object relative to the robot.
• the tolerance relative to the distance measured by this device comprises an infinite distance, the infinite being here defined as the maximum distance measurable by reflection on an object (200) outside the robot.
• the incident laser beam (222) points in a vacuum under nominal operating conditions and the device according to the invention detects any intrusion intersecting said laser beam (222) and producing a reflected beam (224) in the measuring limits of the device.
• an infinite distance measurement indicates the absence of an object in the space covered by the incident beam and the measurement of a particular distance indicates the presence of an object likely to collide with the robot.
• the behavior of the robot in presence of such detection is a function of the distance measured.
• each robot member is individually equipped with the device described above and comprises for this purpose a laser source comprising a photoelectric sensor and a reflecting target, or a laser pointing to an area outside the robot in which is likely to be an object having a surface adapted to reflect the incident beam.
• the optical conduits are not necessary.
• the robot equipped with the device object of the invention itself carries its protection system, and protection of its environment.
• the laser beams in each protective layer do not extend exactly parallel to the members but are organized so as to produce a mesh.
• the laser beams in all or some of the protective layers are curtain-type beams, extending in a plane or in a defined shape, this effect being obtained, for example, by means of an optical device. appropriate.
• the optical conduit (130) comprises a flexible protective sleeve (331), for example cylindrical, supporting at each of its ends an optical device (333, 334), and comprises inside said sleeve (331) and between said optical devices, one or a plurality of optical fibers (335) providing continuity of the light path in said conduit.
• Bearings (341, 342) make it possible to fix each of the ends of said sleeve (341) to each of the members of the robot or manipulator between which it extends.
• said optical fiber or fibers are wound in the helical sleeve so as to facilitate their monitoring of the deformation of said sleeve without exceeding the minimum allowed radius of curvature for said fibers.
• the optical devices (333, 334) make it possible to focus the incident and outgoing laser beams, to direct them in the optical fiber (s), or to the next conduit or target.
• the optical conduit comprises several optical devices corresponding to each of the layers and / or to each of the optical fibers carrying a laser beam.
• the optical devices for collecting the incident beam at the entrance of said duct are of the semi-reflective type and produce a reflection directed, for example, towards the sensor integrated in the laser source.
• said optical devices constitute targets at the passage of each member and allow measurement of the distance traveled by the laser beam along the optical path separating the members or, more simply, to detect an intrusion along one of the members by the absence of beam illuminating the sensor due to the cutting of the incident beam or the reflected beam on said optical device, although the incident beam is pointing into the vacuum at the end of the robot.
• FIG. 4 according to an exemplary embodiment of the method which is the subject of the invention, adapted to an embodiment of the robot, comprising a device able to measure the distance between the laser source and a target on the path of the laser beam, during a first acquisition step (410), a setpoint (415) relative to the potential distance of the target is defined. During a second acquisition step (420) a tolerance (425) relative to said set point is obtained.
• This information is found for example in the memory means of the computer device driving the device object of the invention or is generated by a program implemented by this computing device during a step (430) of definition.
• both the setpoint and the tolerance are updated according to the nature of the tasks performed by the robot, in particular according to the corresponding environment or the speed of movement of the robot during the tasks it performs. .
• the distance (445) between the potential target and the laser source of the device according to the invention is measured by said device.
• the value measured during the measurement step (440) is compared with the nominal values of distance (415) and tolerance (425). If (451) the measured value (445) enters the tolerance, the robot normally continues the execution (490) of its task.
• the information (445) resulting from the measurement step (440) comprises data relating not only to the measured distance parameter, but also to other information such as the laser beam on which this information is measured when the robot is protected by a plurality of laser beams.
• all the information (445) resulting from the measurements made is stored in a file (475) which is analyzed (470) by an expert system, this analysis being used to define the behavior of the robot during the process (460) of setting in safety operation.
• the setpoint and the tolerance relate to a vibration intensity of the target.
• the setpoint (415) or the tolerance (425) on this setpoint comprise an infinite value. That is to say a measuring distance beyond the measuring capacity of the device object of the invention.
• the programmed task of the robot is continued as long as no reflection of the laser beam on a target or an object is detected. In other words, under nominal operating conditions, the laser beam considered point in the void. The presence of a reflection indicates the intrusion of an object into the space thus monitored and triggers the security operation.
• the various embodiments of the method that is the subject of the invention are implemented simultaneously on different laser beams protecting the same robot.
• the device and the method which are the subject of the invention implemented according to their different embodiments make it possible to define a virtual skin, constituted by laser beams, making it possible to detect any intrusion into the space of a robot, without a zone. of shadow, and this before a physical collision occurs between said robot and said intrusion.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Robotics (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Manipulator (AREA)

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• 2016
  • 2016-12-12 FR FR1670755A patent/FR3060182B1/fr active Active
• 2017
  • 2017-12-12 WO PCT/FR2017/053510 patent/WO2018109355A1/fr not_active Ceased
  • 2017-12-12 EP EP17822402.8A patent/EP3551397A1/de not_active Withdrawn

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