Estimation of payload attached to a robot arm
AssigneeUniversal Robots A/S
InventorsAnders Skovgaard KNUDSEN, Andreas Rune FUGL
Life of this patent
Estimating the term…
Abstract
Methods and robot, where payload information of a payload attached to a robot tool flange of a robot arm are obtained by arranging the robot tool flange in a plurality of different orientations in relation to gravity; obtaining the force and the torque provided to the robot tool flange by gravity acting on the payload using a force torque sensor arranged at the robot tool flange; obtaining the mass of the payload based on the obtained forces obtained at at least two of the different orientations. The dependent claims describe possible embodiments of the robot and methods according to the present invention.
Claims20
A method of obtaining information about a payload attached to a tool flange of a robotic arm, where the robotic arm comprises joints connecting a robot base to the tool flange, and where the method comprise:
- arranging the tool flange in different orientations;
- at each of the different orientations, obtaining a force and a torque on the tool flange caused by effects of gravity acting on the payload, the force being obtained using a force-torque sensor at the tool flange;
- obtaining a mass of the payload based on forces on the tool flange produced in at least two of the different orientations;
- and
- obtaining a pose of the payload relative to the tool flange based on the mass of the payload and torques on the tool flange produced in the at least two different orientations;
- wherein arranging the tool flange in the different orientations comprises rotating the tool flange relative to a direction of gravitational force such that an angle between the tool flange and the direction of gravitational force is different for each of the different orientations.
A method of controlling a robotic arm, the robotic arm comprising joints connecting a base of the robotic arm to a tool flange of the robotic arm, the tool flange for holding a payload, the method comprising:
- obtaining a mass of the payload based on differences in force applied by the payload to the tool flange at different orientations of the tool flange;
- obtaining a pose of the payload relative to the tool flange based on differences in torque applied by the payload to the tool flange at the different orientations;
- and
- controlling the joints based on a kinematic model of the robot and information about the payload, where the information comprises the mass of the payload and the pose of the payload relative to the tool flange.
A robot system comprising:
- a tool flange for holding a payload;
- a robotic arm comprising joints connecting a base of a robot to the tool flange;
- at least one controller configured to control the joints based on a kinematic model of the robot and information about the payload, the information comprising a mass of the payload and a pose of the payload relative to the tool flange;
- wherein the controller is configured to perform operations comprising:
- obtaining the mass and the pose based on forces and torques on the tool flange caused by the payload;
- and
- obtaining the forces and the torques based on inputs from a force-torque sensor attached to the tool flange, the inputs being obtained when the tool flange is at different orientations relative to a direction of gravitational force, where an angle between the tool flange and the direction of gravitational force is different for at least some of the different orientations.
Dependencies are inferred from the claim text.