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Method and system for highly precisely positioning at least one object in an end position in space

  • US 8,798,794 B2
  • Filed: 05/26/2010
  • Issued: 08/05/2014
  • Est. Priority Date: 05/27/2009
  • Status: Active Grant
First Claim
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1. A method for highly precisely positioning at least one object in an end position in space by means of an industrial robot, comprising:

  • a first industrial robot, which is adjustable into predeterminable positions; and

    an optical 3D image recording device, which;

    is calibrated in a three-dimensional spatial coordinate system and is positioned in a position with a known alignment;

    is designed for electronically recording three-dimensional images within a specific field of view, wherein the three-dimensional images are in each case composed of a multiplicity of pixels which are each assigned an item of depth information;

    has a drive unit for the alignment, and which brings about adjustment of the field of view, of the 3D image recording device; and

    has an angle measuring unit calibrated in the spatial coordinate system and serving for highly precisely detecting the angular alignment of the 3D image recording device, such that it is possible to determine the field of view in the spatial coordinate system,wherein;

    the position of the 3D image recording device in the spatial coordinate system is determined by aiming at stationary target marks by means of the 3D image recording device;

    a first object, which has known optically detectable first features, is gripped and held by the first industrial robot within a gripping tolerance; and

    a first compensation variable, correcting the gripping tolerance, for the first industrial robot is determined such that the first object is adjustable in a compensated fashion in the spatial coordinate system by predetermining a position of the first industrial robot, wherein the first compensation variable is determined by the steps of;

    aligning the field of view of the 3D image recording device by means of the drive unit with at least one portion of the first features of the first object held in a first compensation position of the first industrial robot;

    recording at least one first three-dimensional image;

    determining the position of the first object in the spatial coordinate system in the first compensation position of the first industrial robot from the position of the 3D image recording device, the angular alignment of the 3D image recording device, said angular alignment being detected by the angle measuring unit, the first three-dimensional image, and the knowledge of the first features on the first object; and

    determining the first compensation variable by utilizing the first compensation position of the first industrial robot, and at least the determined position of the first object in the first compensation position of the first industrial robot; and

    the first object is highly precisely adjusted to a first end position by the following steps, which are repeated until the first end position is reached in a predetermined tolerance;

    recording at least one further first three-dimensional image;

    determining the present position of the first object in the spatial coordinate system from the position of the 3D image recording device, the angular alignment of the 3D image recording device, said angular alignment being detected by the angle measuring unit, the further first three-dimensional image, and the knowledge of the first features on the first object;

    calculating the position difference between the present position of the first object and the first end position; and

    calculating a new desired position of the first industrial robot taking account of the first compensation variable from the present position of the first industrial robot, and a variable which is linked to the position difference and is formed by the position difference multiplied by a factor of less than or equal to 1, and adjusting the first industrial robot to the new desired position.

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