阅读说明：本技术 具有主动校正的加工头、用于操作加工头的方法及其用途 (Machining head with active correction, method for operating a machining head and use thereof ) 是由 伊万·罗斯·维加 卡洛斯·多阿兹·德·拉达 卡洛斯·甘切吉·伊图里亚 于 2020-02-20 设计创作，主要内容包括：本发明涉及具有主动校正的加工头,为与机器人结合使用的类型,用于执行快速高精度加工任务,特别是对航空制造工业的部件,其具有局部位置和角度传感器,加工马达或主轴,设置有独立于机器人的移动相对于加工头壳体的局部移动装置,所述移动优选地是相对于两者的位移和旋转,从而允许主动校正加工位置正。本发明提供的主要优点是在加工定位中允许对于机器人的错误或待加工部件的变形以局部化地非常快速和准确的方式进行校正,而无需对机器人进行重新定位。(The invention relates to a machining head with active correction, of the type used in conjunction with a robot for performing rapid high-precision machining tasks, in particular for components of the aeronautical manufacturing industry, having local position and angle sensors, machining motors or spindles, provided with local movement means relative to the machining head housing independently of the movement of the robot, preferably a displacement and a rotation relative to both, allowing active correction of the machining position. The invention provides the main advantage of allowing corrections in the machining positioning for errors of the robot or deformations of the part to be machined in a very fast and accurate manner in a localized manner without the need to reposition the robot.)

1. A machining head with active correction, of the type used in conjunction with a robot, characterized in that it comprises:

-a housing (1) fixed at the end of the robot (2) by means of attachment and connection means, provided at one end with a pressure foot (3) having a central opening (4),

-a drilling motor (6) with an interchangeable associated tool (7) located inside the casing (1) provided with means for advancing and retracting on the Z axis with respect to the part to be machined (12),

-one or more position and angle sensors (5),

-local movement means for moving the drilling motor (6) relative to the housing (1) independently of the movement of the robot (2),

-means for communicating with a control computer device (15).

2. Machining head with active correction according to the previous claim, wherein the local movement means moving the drilling motor (6) with respect to the casing (1) independently of the movement of the robot (2) comprise:

-means (8) for displacing the assembly of drilling motor (6) and camera (5) in the Y-axis relative to the housing (1),

-means (9) for displacing the assembly of drilling motor (6) and camera (5) in the X-axis relative to the housing (1),

-means (10) for rotating the assembly of drilling motor (6) and camera (5) relative to the housing (1) about the Y-axis, and

-means (11) for rotating the assembly of drilling motor (6) and camera (5) with respect to the housing (1) about the X-axis.

3. Machining head with active correction according to the previous claim, wherein said position and angle sensors (5) are at least two video cameras connected to said drilling motor (6) and associated with artificial vision equipment.

4. Machining head with active correction according to the previous claim, wherein said pressure foot (3) is selected from the group formed by: a pressure foot (3) fixed on the shell (1); and a pressure foot (3) provided with means for independent advance and retraction with respect to the casing (1).

5. Machining head with active correction according to the previous claim, wherein the pressure foot (3) has a surface contact bearing, provided with an angular position sensor as part of the sensor (5).

6. Machining head with active correction according to the previous claim, wherein the control computer device (15) comprises specific software for general joint movements of the robot (2) and the casing (1), correcting the position and angle of the drilling motor (6) with respect to the casing (1) with the local movement means, and processing the signals of the sensor(s) (5).

7. Method of operating a processing head with active correction according to the preceding claim, wherein the method of operating comprises:

-a step of positioning at a set point (13) of a part to be machined (12),

-a step of pushing the machining head onto the part to be machined (12),

-a verification step of verifying the position and angle of the drilling motor (6) and its associated tool (7) by means of the sensor (5),

-if the result of the verification step of the position and angle of the drilling motor (6) and its associated tools (7) by means of the sensor (5) indicates that the actual machining point (14) does not correspond to the set point (13) or that its displacement and/or normal are outside acceptable tolerances, the step of correcting the position and/or normal of the drilling motor (6) and its tools (7) with respect to the casing (1) is performed, then the verification step of the position and angle of the drilling motor (6) and its associated tools (7) by means of the sensor (5) is repeated again, this part of the process being repeated as many times as possible until the position and/or normal are within acceptable tolerances,

-a processing step, and

-exiting step.

8. Method of operating a machining head with active correction according to claim 7, wherein said step of positioning at the set point (13) of the part to be machined (12) comprises:

-moving the housing (1) by means of the robot (2) to centre the central opening (4) of the pressure foot (3) at the set point (13), at a short distance from but not in contact with the component (12) to be machined, and

-if the position and angle sensor (5) is a camera associated with an artificial vision device, taking an image of the surface of the set point (13) of the part to be machined (12) and storing said image in the control computer device (15).

9. Method of operating a machining head with active correction according to claim 7, wherein said step of pushing the machining head onto the part to be machined (12) is performed by the robot (2), moving the casing (1) until its pressure foot (3) comes into contact with the surface of the part to be machined (12) and maintaining the set pressure.

10. Method of operating a machining head with active correction according to claim 7, wherein, in the case where said position and angle sensor (5) is a camera associated with an artificial vision device, the verification step of the position and angle of the drilling motor (6) and its associated tool (7) by means of one or more of said sensors (5) is carried out: -taking a second image of the area where the pressure foot (3) is located by means of one or more of the sensors (5) and comparing it with the previously taken image stored in the control computer device (15), -detecting the same elements of surface roughness in both images by means of an image analysis technique and calculating the possible displacements existing between the two images and the possible variations of the normal of the machining head, which displacements will correspond to the displacements existing between the coordinates of the set point (13) and the coordinates of the actual machining point (14).

11. Method of operating a machining head with active correction according to claim 7, wherein said step of correcting the position of the drilling motor (6) and its tool (7) with respect to the casing (1) comprises:

-activating the local movement means according to the information of the position and angle of the drilling motor (6) and its associated tool (7) provided in the verification step with the sensor (5) to correct the displacements existing of the drilling motor (6) and its tool (7) with respect to the casing (1) if necessary and/or to correct the normal variations existing thereof if necessary.

12. Method of operating a machining head with active correction according to claim 7, wherein said machining step comprises advancing the drilling motor (6) through the pressure foot (3) at the current position and angle.

13. Method of operating a processing head with active correction according to claim 7, wherein said step of exiting comprises:

-moving the drilling motor (6) back inside the housing (1) via the pressure foot (3),

-disconnecting the pressure foot (3) if provided with its own advancing and retreating means,

-moving the housing (1) by the robot (2) until it is separated from the component (12),

-activating the local moving means to bring the drilling motor (6) to its central position without position correction, and

-activating the local moving means to bring the drilling motor (6) to a position parallel to the housing (1) without a normal correction,

the assembly is now ready for another operation.

14. Use of a machining head with active correction and method of operating the same, such as described in the preceding claims 1 to 13, in association with a robot for precision machining.

15. Use of a machining head with active correction and method of operating same as claimed in claim 14, wherein the precision machining is selected from the group consisting of: drilling of parts in the aerospace manufacturing industry for subsequent clinching, milling, rail machining or making cavities.

Technical Field

As its title implies, the present description relates to a machining head with active correction, of the type used in conjunction with robots to perform fast and high precision machining tasks, in particular on components in the aeronautical manufacturing industry, having local position and angle sensors and machining motors or spindles, provided with a local movement arrangement with respect to the machining head housing, independent of the movement of the robot, both in terms of displacement and rotation, or any other axis system that enables the tool to rotate, so that it allows to correct the orientation of the drilling or machining with respect to the surface of the component, thus correcting the position of the drilling tip, eventually correcting the position and angle, allowing to actively correct the machining position, without correcting the axis of the robot itself.

The invention relates to the field of machining heads used with robots in industrial manufacturing.

Background

Various types of robots are currently known and used, in particular in the field of precision machining, in particular for the manufacture of components in the aeronautical industry, where the large number of holes and rivets used makes them indispensable. For this purpose, various types of robots have been used: anthropomorphic, parallel kinematics robots, and the like. During machining, the robot presses the machining head against the part to be machined, or positions the machining head in front, and the machining head itself applies the necessary force by internal means, and then performs the machining operation. However, typically, when the machining head is pressed, the machining head moves slightly or changes its normal line, either because the part yields or deforms slightly with pressure, or because the robot itself yields with pressure, causing the machining head to slip and/or lose or change its normal line (normalad) relative to the part.

In order to avoid the influence of the deformation of the robot or part thereof due to the stress of the pressure foot, there are the following techniques: on the one hand, the precision is improved using an artificial vision system, for example, as described in patent ES2522921 entitled "machining head with vision and automatic machining program", or as described in patent ES2336624 entitled "method of positioning an assembly tool at the end of an articulated arm and at the device for its implementation", which counteracts the effect of the pressure foot by measuring the angle of rotation between a firmly fixed part of the support plate and a second part which can be applied and is stationary with respect to said surface, allowing said parts to be engaged in a relative movement according to at least one pivoting axis. Another known technique is described in patent US 89898989898 entitled "robot manufacturing system with precise control", which adds secondary measurement systems on each axis in view of the lack of stiffness and accuracy of commercial robots, in such a way as to achieve greater precision and stiffness, since if the robot is prone to deformations during the application of the pressure foot, these secondary measurement systems detect these deformations and immediately correct them. However, all these units and methods have the same problem that once a positioning and/or angular error is detected, in order to reposition the machining head in its correct position, or to correct its normal, the entire robot arm must be moved and repositioned at new coordinates, which in some cases means recalculating the error and repeating as many times as necessary until it is correctly positioned within the required tolerances before machining, which affects the speed of the method because the movement of the robot requires a certain positioning time due to its large moving mass and inertia.

Due to the very high demands on positioning accuracy and/or normals, most robots (except for parallel kinematics robots) are no longer able to operate, except for the very fast processing requirements, preventing their use.

Disclosure of Invention

In order to solve the problems of precision and speed of the partial machining by robot that currently exist, it has been envisaged that the object of the invention is a machining head with active correction, consisting of a machining motor or spindle, provided with a local movement relative to the machining head housing independent of the robot movement, preferably displacements in the X, Y and Z axes and rotations relative to the X and Y axes, allowing active correction of the machining position.

For this purpose, the machining head has:

a housing, fixed at the end of the robot, provided with a pressure foot having a central opening,

-a drilling motor, located in said housing, provided with means for advancing and retracting with respect to the part to be machined,

one or more position and angle sensors, preferably a camera associated with an artificial vision device,

-local moving means for moving the drilling motor relative to the housing independently of the movement of the robot,

-means for communicating with a control computer device.

The machining head with active correction is also associated with a specific operating method comprising:

-a step of positioning at set points of the part to be machined,

-a step of pushing the machining head onto the part to be machined,

-a verification step of verifying the position and angle of the drilling motor and its associated tool by means of the sensor,

-if the result of the step of verifying the position and angle of the drilling motor and its associated tool by means of the sensor indicates that the actual machining point does not correspond to the set point, or that its displacement and/or normal is outside acceptable tolerances, the step of correcting the position and/or normal of the drilling motor and its tool with respect to the housing is performed, and then the step of verifying the position and angle of the drilling motor and its associated tool by means of the sensor is repeated again, this part of the process being repeated as many times as possible until the position and/or angle is within acceptable tolerances,

-a processing step, and

-exiting step.

The purpose of such a machining head with active correction and its method of operation is precision machining, preferably for drilling holes in parts for the aeronautical manufacturing industry for subsequent riveting.

Advantages of the invention

The proposed machining head with active correction offers several advantages over currently available systems, the most important being that once the machining head is under pressure on the part, the subsequent repositioning to correct the error does not require moving the entire robot, but only the spindle, which can move faster due to its low mass, with less inertia and greater accuracy, whereas moving the entire robot is a relatively slow process due to the large mass to be moved, and lacks axis precision due to the drive itself and the large actuator stem.

For this reason, it is worth noting that it allows the robot to correct errors in the positioning for machining in a fast, accurate manner, without having to reposition the robot.

It is important to emphasize that if the verification process has to be repeated several times, since the movement is short and local, the operation of the component is not affected unlike the conventional method in which the process has to be repeated by the robot moving the whole component repeatedly.

Another important advantage is that this allows the use of lower precision robots, such as anthropomorphic robots for precision machining tasks, without the need for high processing times for repositioning.

A further advantage of the present invention is that because it allows the use of anthropomorphic robots, it can be reused in manufacturing processes requiring greater speed and accuracy without having to make large financial investments.

It must also be mentioned that the use of sensors for measuring and verifying position and angle adds greater speed and precision to the operation.

Interestingly, it is highlighted that the machining heads can be used with all types of robots, allowing to significantly improve their positioning speed and accuracy, making them easy to produce with demanding machining and enabling their service life to be extended.

Drawings

In order to provide a better understanding of the invention, a preferred practical embodiment of the machining head with active correction is shown in the drawing, with a camera as sensor.

In said drawings, fig. 1 shows a simplified overall view of the machining head in its rest position.

Fig. 2 shows a simplified overall view of the machining head, in a step of positioning at a setpoint of the component to be machined and in a step of taking an image of the surface of the setpoint of the component to be machined.

Fig. 3 shows a simplified overall view of the machining head, in the step of pushing the machining head onto the part to be machined.

Fig. 4 shows a simplified overall view of the machining head, in a visual verification step of the position of the drilling motor and its associated tool, in which case, after the step of pressing the machining head onto the part to be machined, there is a linear and/or angular displacement of the machining head with respect to the part, due to the effect of the pressure.

Fig. 5 shows a simplified overview of the machining head, in the step of correcting the position of the drilling motor and its tool relative to the housing.

Fig. 6 shows a simplified overview of the machining head, at a machining step after the position of the drilling motor and its associated tool has been corrected and verified.

Fig. 7 shows a simplified overview of the machining head, in the step of visual verification of the position of the drilling motor and its associated tool, in which case, after the step of pressing the machining head onto the part to be machined, the normal of the machining head with respect to the part changes due to the effect of the pressure.

Fig. 8 shows a simplified overview of the machining head, at the step of correcting the normal of the drilling motor and its tools with respect to the housing.

Figure 9 shows a simplified overview of the machining head, after having previously corrected the normal, the step of correcting the position of the drilling motor and its tools relative to the housing.

Fig. 10 shows a simplified overview of the machining head in a machining step after the normals and positions of the drilling motor and its associated tool have been corrected and verified.

Fig. 11 shows an example of installation of a robot with this processing head.

Fig. 12 shows a detail of a part of an exemplary element of the machining head.

Figure 13 shows an external view of an example of a machining head.

Fig. 14 shows a detail of a part of the elements in the example of the machining head in a transparent manner.

Fig. 15 shows a detail of a part of an exemplary element of the machining head.

Detailed Description

The construction and features of the invention will be better understood in the following description of the drawings.

As can be seen in fig. 1, 11, 12, 13, 14 and 15, a processing head with active correction is shown, of the type used in association with a robot to perform fast high-precision processing tasks, comprising:

-a housing (1) fixed at the end of the robot (2) by means of attachment and connection means, provided at one end with a pressure foot (3) having a central opening (4),

-a drilling motor (6) or spindle with an interchangeable associated tool (7) located inside the housing (1) provided with means for advancing and retracting on the Z axis with respect to the part to be machined (12),

-one or more position and angle sensors (5),

-local movement means for moving the drilling motor (6) relative to the housing (1) independently of the movement of the robot (2),

-means for communicating with a control computer device (15).

The local movement device for moving the drilling motor (6) relative to the housing (1) independently of the movement of the robot (2) preferably comprises:

-means (8) for displacing the assembly of drilling motor (6) and camera (5) in the Y-axis relative to the housing (1),

-means (9) for displacing the assembly of drilling motor (6) and camera (5) in the X-axis relative to the housing (1),

-means (10) for rotating the assembly of drilling motor (6) and camera (5) relative to the housing (1) about the Y-axis, and

-means (11) for rotating the assembly of drilling motor (6) and camera (5) with respect to the housing (1) about the X-axis.

The means (8) for displacement in the Y-axis and the means (9) for displacement in the X-axis comprise a combination of motors with a drive system, such as a tapped bevel gear and a straight rack, a spindle or a cam.

The means (10) of rotation about the Y axis and the means (11) of rotation about the X axis comprise a combination of motor drive systems, such as guides and curved racks.

The one or more sensors (5) may be optical sensors, cameras, distance sensors, pressure sensors, laser profilometers, etc. or any combination thereof. In a preferred embodiment, the position and angle sensors (5) are at least two cameras attached to the drilling motor (6) and associated with the artificial vision equipment.

The pressure foot (3) may be a pressure foot (3) fixed to the housing (1) and thus moved by the robot (2), or a pressure foot (3) provided with means for advancing and retracting independently with respect to said housing (1). In a preferred embodiment, the pressure foot (3) has a surface contact bearing, an angular position sensor being provided as part of said sensor (5).

The control computer device (15) comprises specific software for general joint movements of the robot (2) and the housing (1), correcting the position and angle of the drilling motor (6) relative to the housing (1) with the local movement means, and processing the signals of one or more of the sensors (5).

The machining head with active correction is also associated with a particular operating method shown in fig. 2, 3, 4, 5, 6, 7, 9 and 10, which comprises:

-a step of positioning at a set point (13) of a part to be machined (12),

-a step of pushing the machining head onto the part to be machined (12),

-a verification step of verifying the position and angle of the drilling motor (6) and its associated tool (7) by means of the sensor (5),

-if the result of the verification step of the position and angle of the drilling motor (6) and its associated tools (7) by means of the sensor (5) indicates that the actual machining point (14) does not correspond to the set point (13) or that its displacement and/or normal are outside acceptable tolerances, the step of correcting the position and/or normal of the drilling motor (6) and its tools (7) with respect to the casing (1) is performed, then the verification step of the position and angle of the drilling motor (6) and its associated tools (7) by means of the sensor (5) is repeated again, this part of the process being repeated as many times as possible until the position and/or normal are within acceptable tolerances,

-a processing step, and

-exiting step.

The step of positioning at a set point (13) of a part to be machined (12) comprises:

-moving the housing (1) by means of the robot (2) to centre the central opening (4) of the pressure foot (3) at the set point (13), at a short distance from but not in contact with the component (12) to be machined, and

-if the position and angle sensor (5) is a camera associated with an artificial vision device, taking an image of the surface of the set point (13) of the part to be machined (12) and storing said image in the control computer device (15).

The step of pushing the machining head onto the part to be machined (12) is carried out by the robot (2), moving the casing (1) until its pressure foot (3) comes into contact with the surface of the part to be machined (12) and maintaining a set pressure.

In case the position and angle sensor (5) is a camera associated with an artificial vision device, the step of verifying the position and angle of the drilling motor (6) and its associated tool (7) by means of one or more of the sensors (5) is performed by: -taking a second image of the area where the pressure foot (3) is located by means of one or more of the sensors (5) and comparing it with the previously taken image stored in the control computer device (15), -detecting the same elements of surface roughness in both images by means of an image analysis technique and calculating the possible displacements existing between the two images and the possible variations of the normal of the machining head, which displacements will correspond to the displacements existing between the coordinates of the set point (13) and the coordinates of the actual machining point (14).

The step of correcting the position of the drilling motor (6) and its tool (7) relative to the housing (1) comprises:

-activating the local movement means according to the information of the position and angle of the drilling motor (6) and its associated tool (7) provided in the verification step with the sensor (5) to correct the displacements existing of the drilling motor (6) and its tool (7) with respect to the casing (1) if necessary and/or to correct the normal variations existing thereof if necessary.

The machining step comprises advancing the drilling motor (6) through the pressure foot (3) at a current position and angle.

The exiting step comprises:

-moving the drilling motor (6) back inside the housing (1) via the pressure foot (3),

-disconnecting the pressure foot (3) if provided with its own advancing and retreating means,

-moving the housing (1) by the robot (2) until it is separated from the component (12),

-activating the local moving means to bring the drilling motor (6) to its central position without position correction, and

-activating the local moving means to bring the drilling motor (6) to a position parallel to the housing (1) without a normal correction,

the assembly is now ready for another operation.

The purpose of such a machining head with active correction and its method of operation is for precision machining, preferably for drilling holes in components in the aeronautical industry for subsequent back riveting, front riveting, milling, orbital machining or for the production of cavities.

A person skilled in the art will readily understand that the features of the different embodiments can be combined with the features of the other possible embodiments as long as this combination is technically feasible.

All information relating to the examples or embodiments forms part of the description of the invention.