Method and system to provide improved accuracies in multi-jointed robots through kinematic robot model parameters determination

A system providing improved pose accuracies in a robot having a multi-jointed arm, said system comprising:

• a controller configured to interpret coordinates within a three dimensional space, move the multi-jointed arm to a location within the three dimensional space that corresponds to the coordinates, and determine joint values of each joint in the multi-jointed arm;
• a pair of reference objects each of a known geometry situated within the three dimensional space, each said reference objects defining a unique constraint point of unknown pose and the distance between constraint points from said reference objects forming a known constraint distance therebetween;
• an effector object provided on the multi-jointed arm, said effector object is configured to indicate an encounter with at least one of said reference objects;
• and
• a processor configured to perform parameter identification,
• wherein said controller is configured to:
• provide a plurality of encounters of said effector object with said reference objects, and,
• wherein said controller is comprised of said processor, which processor is configured to:
• determine joint values of the multi-jointed arm for each of said encounters,
• calculate 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 calculated pose of the constraint point of said first reference object,
• calculate 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 calculated pose of the constraint point of said second reference object,
• calculate 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,
• calculate 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,
• identify kinematic model parameters of said robot model and said trial poses of the constraint points of said pair of reference objects, which minimize said first and second differences, and
• wherein said controller is further configured to use said identified kinematic model parameters for improved pose accuracies in the multi-jointed robot.