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Method and System to Provide Improved Accuracies in Multi-Jointed Robots Through Kinematic Robot Model Parameters Determination

  • US 20080188986A1
  • Filed: 10/25/2005
  • Published: 08/07/2008
  • Est. Priority Date: 10/25/2004
  • Status: Active Grant
First Claim
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1. A method providing improved pose accuracies in a multi-jointed robot, said method comprising:

  • providing a pair of reference objects each of a known geometry and each defining a unique constraint point of unknown pose, distance between constraint points from said reference objects forming a known constraint distance;

    providing an effector object on the robot, said effector object is movable by the robot in at least two axes and is configured to indicate an encounter with at least one of said reference objects;

    providing a plurality of encounters of said effector object with said reference objects;

    determining joint values of the robot for each of said encounters;

    calculating a first pose of a first reference point from said joint values determined from at least four of said encounters with a first one of said reference objects, said first pose corresponding to a first calculated pose of said constraint point of said first reference object;

    calculating a second pose of a second reference point from said joint values determined from at least four of said encounters with a second one of said reference objects, said second pose corresponding to a second calculated pose of said constraint point of said second reference object;

    calculating a first difference between said first or second pose and a trial pose of said constraint point for said first or second reference object, respectively;

    calculating a second difference between a calculated constraint distance and said known constraint distance, said calculated constraint distance is the distance between said trial poses of said constraint points of said pair of reference objects;

    identifying kinematic model parameters of said robot model and trial poses of said constraint points of said pair of reference objects which minimize said first and second differences; and

    ,using said identified kinematic model parameters for improved pose accuracies in the multi-jointed robot.

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