MULTI-AXIS ROBOT AND METHOD FOR CONTROLLING THE SAME FOR PAINTING OBJECTS

Abstract

A multi-axis robot having a kinematic chain with a tool member and at least one additional member, the tool member supporting a first tool. The associated robot control mechanism comprises a kinematic control mechanism designed to receive the movement path of the first tool using a parameterizable tool center point and to control members of the kinetic chain in such a way that the tool center point follows the movement path. The robot control mechanism maintains all the members along the kinematic chain of the tool member of another member which supports the second tool in a fixed position, it parameterizes the tool center point on a working point of the second tool, and transfers the movement path of the second tool to the kinematic control mechanism so that the latter, under the condition that the fixed position of the members is maintained, controls the remaining members of the kinematic chain using the newly parameterized tool center point so that the tool center point follows the movement path of the second tool.

Claims

1. A multi-axis robot comprising: a) a kinematic chain which has a tool member and at least one further member, b) the tool member carrying a first tool, a robot controller which, in order to control the first tool, comprises a kinematic controller which is set up to accept a movement path of the first tool using a parameterizable tool center point and thereupon to actuate the at least one further member of the kinematic chain in such a way that the tool center point follows the movement path, wherein d) the at least one further member carries a second tool, and in that e) the robot controller is set up to control the second tool in such a way that it fixes any members along the kinematic chain from the tool member to the at least one further member which carries the second tool in a fixing position, parameterizes the tool center point to a working point of the second tool, and transfers a movement path of the second tool to the kinematic controller, with the result that said kinematic controller, under the secondary condition that the fixing position of the members is maintained, actuates any remaining members of the kinematic chain using the newly parameterized tool center point in such a way that the tool center point follows the movement path of the second tool.

2. The multi-axis robot as claimed in claim 1, wherein the fixing position corresponds to a position which the member or members to be fixed assume immediately before the change to the second tool.

3. The multi-axis robot as claimed in claim 1, wherein the outer contour of the fixed part of the kinematic chain is also parameterized during the parameterization of the tool center point to the working point of the second tool.

4. The multi-axis robot as claimed in claim 1, wherein the at least one further member carries a plurality of second tools, and in that the robot controller is set up to parameterize the tool center point in each case to that second tool which is to be controlled.

5. The multi-axis robot as claimed in claim 1, wherein a plurality of second tools are arranged on different further members and, in order to control the respective second tool, the robot controller is set up such that it fixes the corresponding members along the kinematic chain from the tool member to the respective further member which carries the respective second tool in a fixing position, and that it parameterizes and actuates the kinematic controller correspondingly.

6. A paint shop for painting objects comprising a multi-axis robot as claimed in claim 1.

7. A method for controlling a multi-axis robot comprising the following steps: a) providing of a robot controller for controlling a multi-axis robot having a kinematic chain which has a tool member and at least one further member, it being possible for the tool member to carry a first tool and for the at least one further member to carry a second tool, the robot controller comprising a kinematic controller (51) which is set up to accept a movement path of the first tool using a parameterizable tool center point and thereupon to actuate the members of the kinematic chain in such a way that the tool center point follows the movement path; b) fixing of all the members along the kinematic chain from the tool member to the at least one further member which carries the second tool in a fixing position; c) parameterizing of the tool center point of the kinematic controller to a working point of the second tool; d) transferring of the movement path of the second tool to the kinematic controller, with the result that said kinematic controller, under the secondary condition that the fixing position of the members is maintained, actuates the remaining members of the kinematic chain using the newly parameterized tool center point in such a way that the tool center point follows the movement path of the second tool.

8. The method for controlling a multi-axis robot as claimed in claim 7, wherein the following steps are carried out beforehand: a) programming of the movement path of the first tool with the aid of a tool center point; b) programming of the movement path of the second tool with the aid of a tool center point under the secondary condition that the fixing position of the members is maintained.

9. A method for painting an object with a movable component comprising the following steps: a) providing of a painting robot, with a kinematic chain which has a tool member and at least one further member, the tool member carrying an application unit as a first tool, and the at least one further member carrying a second tool; b) using of the method as claimed in claim 7 to control the painting robot, in order to move the movable component with the second tool; c) painting of the object before and/or after the movement of the movable component with the aid of the application unit.

10. A method for implementing a multi-axis robot comprising the following steps: a) providing a multi-axis robot having a kinematic chain which has a tool member and at least one further member, it being possible for the tool member to carry a first tool, in particular an application unit, and for the at least one further member to carry a second tool; b) programming of the movement path of the first tool, in particular of the application unit, into a kinematic controller which is set up to accept the movement path of the first tool using a parameterizable tool center point and thereupon to actuate the members of the kinematic chain in such a way that the tool center point follows the movement path; b) fixing of all the members along the kinematic chain from the tool member to the at least one further member which carries the second tool in a fixing position; c) parameterizing of the tool center point of the kinematic controller to a working point of the second tool; d) programming of the movement path of the second tool into the kinematic controller, with the result that said kinematic controller, under the secondary condition that the fixing position of the members is maintained, can actuate the remaining members of the kinematic chain using the newly parameterized tool center point in such a way that the tool center point follows the movement path of the second tool.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In the following text, exemplary embodiments of the invention will be described in greater detail using the drawings, in which:

[0048] FIG. 1 shows a perspective view of a paint shop with two multi-axis robots as painting robots;

[0049] FIG. 2 shows a diagrammatic partial view in cross section through the paint shop, which partial view illustrates the programming of a movement path of an application unit;

[0050] FIG. 3 shows a diagrammatic partial view in cross section through the paint shop, which partial view illustrates the programming of a movement path of another actuating element; and

[0051] FIG. 4 shows a flow chart which shows the method steps for the reduction of the kinematics.

DESCRIPTION OF PREFERRED EXEMPLARY EMBODIMENTS

[0052] FIG. 1 shows a perspective view of a detail of an exemplary paint shop 10 which is provided here for painting vehicle bodies 12 or their fixtures which have, for example, an engine hood 13 as a movable component.

[0053] To this end, the vehicle bodies 12 are moved with the aid of a conveying device 14 through a paint booth 16, in which multi-axis robots are arranged as painting robots 18.

[0054] In the exemplary embodiment which is shown here, a painting robot 18 of this type first of all has a pedestal 20 and a trunk element 22. A triaxial joint 24 which establishes an articulated connection to a first arm section 26 is arranged on said trunk element 22 at the upper end. A uniaxial joint 28 which for its part establishes an articulated connection between the first arm section 26 and a second arm section 30 is arranged at the other end of the first arm section 26. A triaxial joint 32 which for its part carries a third arm section 34 is in turn arranged on the second arm section 30. Said third arm section 34 has a uniaxial joint 36 which carries a hand section 38, on which the first tool (in this case, a rotation atomizer 40 with a bell disk) is mounted.

[0055] Furthermore, the painting robot 18 has an actuating element as a second tool (here, an engine hood opener 42 by way of example) on the second arm section 30. Here, furthermore, a fuel filler flap opener 43 is provided on the same second arm section 30, moreover, as a second tool which can be used as an alternative.

[0056] The different joints and sections of the painting robot 18 from the pedestal 20 as far as the hand section 30 together form the kinematic chain of the painting robot 18.

[0057] In order to fix how the rotation atomizer 40 moves around the vehicle body 12, the rotation atomizer 40 is assigned what is known as a tool center point 44 as a reference point, as can be seen from FIG. 2. Said tool center point 44 can be that point, at which the rotation atomizer 40 emits its optimum jet pattern. Said tool center point 44 is then guided as needed over the surface of a vehicle body 12 to be painted in each case during the implementation phase of the paint shop 10. Here, the tool center point 44 can also be guided in front of or behind the actual vehicle body surface, in order to produce a larger or smaller painting patch, for example.

[0058] In order to control the robot 18, said robot 18 is connected to a robot controller 50 which comprises a kinematic controller 51 which is typically included by the manufacturer of the corresponding multi-axis robot. The robot controller is connected to an operating computer 52 for programming purposes.

[0059] A tool zero point 54 is stored in the kinematic controller 51, with regard to which tool zero point 54 the tool center point 44 is fixed depending on the tool. In FIG. 2, this is indicated by way of the double arrow a which it goes without saying is to be considered vectorially. If the painting robot 18 is operated with another tool, for example as a result of an automated tool change during a painting process or between different painting processes, for example in the case of the change to other vehicle bodies 12, the tool center point 44 can thus be newly parameterized.

[0060] Via the operating computer 52, the movement path of the tool center point 44 or the rotation atomizer 40 including its orientation along the vehicle body 12 is then programmed in a simple way, for example in the form of a multiplicity of individual support points of a spline curve.

[0061] In order to open and to close the engine hood of the vehicle body 12, for example, during a painting process, the engine hood opener 42 is used. On account of the fact that the engine hood opener 42 is arranged on the second arm section 30 and the rear joints and members and the associated actuators of the painting robot 18 are by nature of larger dimensions than the front elements, the painting robot 18 is capable of this, since a sufficient force can then be applied by way of the engine hood opener 42.

[0062] In order to also achieve a simple programmability with the aid of the kinematic controller 51 for the movement of the engine hood opener 42, the two last joints 32 and 36 are fixed either in their instantaneous position or in a position fixed in advance (as indicated in FIG. 3 by way of the dashing). In a manner which is dependent on the fixed position, the tool center point 44 is then parameterized with regard to the tool zero point 54 to the working point of the engine hood opener 42 (cf. double arrow b).

[0063] As in the case of the rotation atomizer 40 which is attached at the front of the painting robot 18, furthermore, the moment of inertia of the corresponding components, by which the kinematic chain of the painting robot 18 has been reduced by way of the fixing of the joints 32 and 36, is parameterized. Afterward, the engine hood opener 42 can be controlled in accordance with its required movement path via the customary kinematic controller 51 with the aid of a path planning operation. For this purpose, the operating computer 52 accesses the known kinematic controller 51 via the robot controller 50, the joints 32 and 36 remaining fixed as a secondary condition in the kinematic model.

[0064] In the same way as the control operation of the engine hood opener 42 takes place, the fuel filler flap opener 43 can also be operated. Here, the tool center point 44 is then defined in a correspondingly differing manner in the kinematic controller 51. If the fuel filler flap opener 43 were arranged on another member of the kinematic chain, correspondingly more or fewer joints would have to be fixed.

[0065] In the present exemplary embodiment, the invention has been described using a painting robot 18 with four joints, on which the robot kinematics have been reduced by the last two joints for the path planning operation. It goes without saying that it is clear to a person skilled in the art, however, that this principle can basically be extended as desired to the extent that more or fewer members are available as degrees of freedom and a reduction by more or fewer members takes place.

[0066] In this way, it is possible, even in the case of in future even more slender multi-axis robots with regard to different members of the kinematic chain, to perform the programming of the individual tools, by the known means of a path planning operation being relied upon.