HEAD AND AUTOMATED MECHANIZED METHOD WITH VISION

• US 20160082598A1
• Filed: 05/15/2014
• Published: 03/24/2016
• Est. Priority Date: 05/17/2013
• Status: Active Grant

• Current Assignee: Loxin 2002, S.L. (COMSA Corporación de Infraestructuras SL)
• Original Assignee: Loxin 2002, S.L. (COMSA Corporación de Infraestructuras SL)
• Inventors: ANDUCAS AREGALL, Jordi, GANCHEGUI ITURRIA, Carlos, GALARZA CAMBRA, Jose Javier
• Granted Patent: US 9,919,428 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B21J 15/142 Aerospace structures
• CPC Class Codes: B25J 11/005 Manipulators for mechanical processing tasks
• CPC Class Codes: B25J 11/007 Riveting
• CPC Class Codes: B25J 19/02 Sensing devices
• CPC Class Codes: B25J 19/022 using lasers
• CPC Class Codes: B25J 19/023 including video camera means
• CPC Class Codes: B25J 9/1692 Calibration of manipulator
• CPC Class Codes: B25J 9/1697 Vision controlled systems
• CPC Class Codes: G06T 1/0014 Image feed-back for automatic industrial control, e.g. robot with camera robots B25J19/023
• CPC Class Codes: Y10S 901/10 Sensor physically contacts and follows work contour

Abstract

An automated machining head with vision and procedure includes a pressure foot provided with side windows with the capacity to open and close, encasing the machining tool, associated with a vertical movement device provided with mechanical locking, vision equipment connected to a computer and a communications module. The main advantage is endowing an anthropomorphic robot, originally designed for the car industry and with relatively low accuracy, with a notably higher machining accuracy, equivalent to equipment of a much greater accuracy or to parallel kinematic-type robots, also compensating, in real-time and in a continuous manner, for off-centring and loss of perpendicularity by the pressure foot, which are common in conventional heads and are a source of errors and inaccuracy.

Claims

1. Automated machining head with vision, of the type used industrially associated with robot arms (1), to perform various machining tasks, such as drilling and riveting, controlled by a robot controller module (2) characterised in that it comprises:

a pressure foot (3), encasing the machining tool (4),

the said pressure foot (3) associated with a vertical movement device (5) provided with mechanical locking (6)

vision equipment provided with at least two video cameras (7), connected to a computer (8) provided with specific software (9), and

a communications module (10)

2. Automated machining head with vision, according to claim 1, wherein the vision equipment comprises a laser device (15) that projects a cross-shaped beam.

3. Automated machining head with vision, according to claim 1, wherein the pressure foot (3) is formed by a hood provided with side windows (11) that allow video cameras (7) to view the machining tool (4) located inside it and its work surface.

4. Automated machining head with vision, according to claim 3, wherein the side windows (11) of the pressure foot (3) have closures (12) that block the video cameras'"'"' (7) view of the machine tool (4) located inside it, preventing swarf from coming out during machining.

5. Automated machining head with 3D vision, according to claim 4, wherein the closures (12) of the side windows (11) of the pressure foot (3) are achieved by means of a concentric second hood (13) of the pressure foot (3) provided with the capacity to rotate in relation to the latter, and provided with openings coincident with the side windows (11) in an open position, and non-coincident in a closed position of the pressure foot (3).

6. Operating procedure of an automated machining head with vision such as that described in claim 5, wherein it carries out corrections to the orders of the robot controller module (2) according to the image received from the video camera or video cameras (7) that form the vision equipment, and it includes

a first phase of measuring on the workpiece to be machined,

a second phase of positioning the head at the target work point,

a third phase of correcting the position and orientation of the head via vision, and

a fourth phase of machining or a specific operation for which the device has been designed.

7. Operating procedure of an automated machining head with vision, according to claim 6, wherein in the first phase of measuring, reference points are taken via the video cameras (7) that form the vision equipment, on the workpiece to be machined in the zone near to the area to be machined, taking a minimum of two points to plot a virtual line, or a minimum of three points to determine a reference plane, including

a first step of determining the reference points,

a second step of determining the positioning on the line or plane that the previously calculated reference points create, and

a third step of predicting or estimating, via specific software (9) incorporated in the computer (8), the positioning errors that the robot (2) is going to make when it is directed to an intermediate point between the references taken, and thus, the final position can be corrected.

8. Operating procedure of an automated machining head with vision, according to claim 7, wherein the step of determining the reference points includes

a first operation in which reference point 1 is measured with the vision equipment in position 1

a second operation in which the robot (2) repositions to the new position 1, now position 2, by means of the measured data,

a third operation in which the machining head carries out a translation/rotation,

a fourth operation in which it returns to position 2,

a fifth operation in which it reference point 1 is measured again,

a sixth operation in which the robot (2) repositions to the new position 2, now position 3, by means of the measured data,

a seventh operation in which the machining head carries out a translation/rotation,

an eighth operation in which it returns to position 3, and

a ninth operation in which reference point 1 is measured and is stored as the control point, these operations being repeated for each of the reference points.

9. Operating procedure of an automated machining head with vision, according to claim 7, wherein the step of determining the positioning on the line or plane that the previously calculated reference points create, includes

a first operation in which the real distance between each two reference points is entered, and

a second operation in which, via the specific software (9) incorporated in the computer (8) the corrections that must be applied to the intermediate and/or near points of the line or plane created by the reference points, determined by means of the real value of the said reference points, are calculated.

10. Operating procedure of an automated machining head with vision, according to claim 6, wherein the second phase of positioning the head in the zone to be machined comprises a step of moving the head, via the movement of the robot arm (1) ordered by the robot controller module (2), to the coordinates at which machining is required.

11. Operating procedure of an automated machining head with vision, according to claim 6, wherein the third phase of correcting the position of the head via vision, comprises a first step in which, in the case of normal surfaces that are not shiny or polished, a reference image of the workpiece is taken by means of the video cameras (7) which form the vision equipment, through the side windows (11) of the pressure foot (3), that will be in their open position, analyzing its roughness via the specific software (9) incorporated in the computer (8) and locating the operating point in relation to it.

12. Operating procedure of an automated machining head with vision, according to claim 6, wherein the third phase of correcting the position of the head via vision comprises a first step in which, in the case of very shiny or polished surfaces, the head itself makes a small mark or pecking, acting lightly with the machining tool (4) on the target point on the workpiece surface of which a reference image will be taken via the video cameras (7) that form the vision equipment, through the side windows (11) of the pressure foot (3), that will be in their open position, prior to the application of additional forces, identifying it, by means of the image of the said mark, as a reference.

13. Operating procedure of an automated machining head with vision, according to claim 6, wherein the third phase of correction of the position of the head by means of vision includes

a second step of descent of the pressure foot (3), by means of the vertical movement device (5), onto the surface to be machined in which the consequent force exerted by the pressure foot (3) on the zone to be machined, causes the movement of the robot arm (1), which involves a deviation from the position and orientation originally required, entailing a positioning error, followed by

a third step in which the vision system, comparing the image obtained now by the video cameras (7) which form the vision equipment, through the side windows (11) of the pressure foot (3), which will remain in their open position, with the reference image obtained in the first step and which is used as a reference, generates an order for the robot arm (1) to move in the required direction, again taking another image of the surface to be machined, through the side windows (11) of the pressure foot (3), repeating this phase until the image coincides with the reference image around the operating point, that is, until the coordinates of the current operating point coincide with those established in the second phase of positioning the head, and the orientation achieved coincides with that required, which may be that of the reference obtained in the first step, or simply the normal to the surface at the operating point.

14. Operating procedure of an automated machining head with vision, according to claim 6, wherein the fourth phase of machining comprises

a first step of mechanical locking of the vertical movement device (5) of the pressure foot (3),

a second step of activation of the closures (12) of the side windows (11) of the pressure foot (3), and

a third phase of the machining tool (4) located inside it, to perform the machining of the surface.

15. Operating procedure of an automated machining head with vision, according to claim 6, wherein it includes a prior optional calibration phase, which consists of using a calibrating tool (14) to adjust the head'"'"'s operating parameters, in such a way that in the said calibration phase the correlation is found between the coordinates system of the machining tool, that of the vision system and that of the robot controller.