US 8,509,941 B2Granted

Method and device for fine positioning of a tool having a handling apparatus

AssigneesFraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V., Rheinisch-Westfaelische Technische Hochschule Aachen

InventorsBoris Regaard, Stefan Kaierle

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Abstract

The present invention relates to a method and a device for the machining of an object using a tool, in which the tool (2) or the object (18) is guided using a handling apparatus, which has multiple movement axes for the coarse positioning of the tool (2) or object (18), which form a kinematic chain. In the method, an additional actuator (3), which has a higher positioning precision in at least one dimension or axis than the other movement axes, is inserted between a terminal link (1) of the kinematic chain and the tool (2) or object (18). A relative movement of the tool (2) or terminal link (1) of the kinematic chain to the object (18) is detected using at least one sensor (5) and a deviation from a target movement path is compensated for using the additional actuator (3). The method and the associated device allow the use of robots or other handling apparatuses having lower path precision for applications which require a high precision during the guiding of the tool.

Claims16

Dependent claims

A method for fine positioning of a tool during machining of an object, in which the tool or the object is guided by a handling apparatus having multiple movement axes for a coarse positioning of the tool or the object, wherein the multiple movement axes form a kinematic chain, the handling apparatus further having an actuator situated between a terminal link of the kinematic chain and the tool or the object, wherein the actuator has a higher positioning precision than the other movement axes in at least one dimension or axis, the method comprising:

detecting a relative velocity and a relative direction of movement between the object and the tool or terminal link of the kinematic chain by using at least one sensor, wherein the at least one sensor comprises a camera;
illuminating a surface of the object in the area of a machining point using optical radiation;
repeatedly detecting optical radiation reflected from the surface of the object in an area of the machining point using the camera, in order to obtain optical reflection patterns of the surface of the object at different times, wherein the repeated detection occurs at time intervals in which chronologically sequential reflection patterns of overlapping surface areas of the object are obtained;
ascertaining the relative velocity and the relative direction of movement by comparing the chronologically sequential reflection patterns;
calculating an actual movement path of the tool, the object, or the terminal link from the relative velocity and relative direction of movement;
and
compensating a deviation of the actual movement path from a target movement path, by positioning of the tool or the object using the actuator based on the deviation.

4 more elements

A device for the fine positioning of a tool during the machining of an object, comprising:

a handling apparatus having multiple movement axes for a coarse positioning of a tool or object, which multiple movement axes form a kinematic chain;
an actuator fastened on a terminal link of the kinematic chain to allow a fine positioning of the tool or object in at least one dimension or axis at a higher precision than the other movement axes;
at least one sensor to detect a relative velocity and a relative direction of movement between the object and the tool or terminal link of the kinematic chain, wherein the sensor is a camera;
a machining head, which includes a coupling opening for a machining beam and a beam shaping optic to direct the machining beam along a beam axis through an outlet opening on a machining plane lying in front of the machining head, wherein the sensor is connected mechanically fixed to the machining head and is situated to detect the optical radiation reflected from the machining plane parallel or at a small angle to the beam axis in a locally-resolved way;
and
a control unit having an image processing algorithm for analyzing chronologically sequential reflection patterns for the automated determination of the relative velocity and the relative direction of movement between the machining head and the object, wherein the control unit activates the actuator to compensate a deviation of an actual movement path of the tool, the object, or the terminal link from a target movement path, which deviation is calculated from measured data of the sensor.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/446,407Filed 18 Oct 2007
Priority: DE 10 2006 049 62720 Oct 2006
Published: US 2010/0324735 A123 Dec 2010
Granted: 13 Aug 2013
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

B25J 9/1015
Comprising adjusting means: using additional, e.g. microadjustment of the end effector
B25J 9/1684
Characterised by the tasks executed: tracking a line or surface by means of sensors
Y10T 74/20335
Joint between elements: wrist
Y10T 74/20341
Multiple controlling elements for single controlled element: power elements as controlling elements