Obtaining the gear stiffness of a robot joint gear of a robot arm
AssigneeUniversal Robots A/S
InventorEmil MADSEN
Life of this patent
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Abstract
A method of obtaining the gear stiffness of a robot joint gear of a robot joint of a robot arm, where the robot joint is connectable to at least another robot joint. The robot joint comprises a joint motor having a motor axle configured to rotate an output axle via the robot joint gear. The method comprises the steps of: —applying a motor torque to the motor axle using the joint motor; —obtaining the angular position of the motor axle; —obtaining the angular position of the output axle; —determining the gear stiffness based on at least the angular position of the motor axle, the angular position of the output axle and a dynamic model of the robot arm.
Claims20
A method of obtaining a stiffness of a gear of a joint on a robotic arm, where the joint is connectable to at least one other joint on the robotic arm, where the joint comprises a motor having a motor axle, where the motor axle is configured to rotate an output axle through the gear, and where the method comprises:
- applying torque to the motor axle using the motor;
- obtaining an angular position of the motor axle;
- obtaining an angular position of the output axle, and
- determining the stiffness of the gear based on at least the angular position of the motor axle, the angular position of the output axle, and a dynamic model of the robotic arm, where the dynamic model defines a relationship between forces acting on the robotic arm and resulting accelerations of the robotic arm.
A system comprising a robotic arm, the system comprising:
- joints in the robotic arm, a combination of the joints connecting a base and a tool flange;
- at least one controller to control the joints based on a dynamic model of the robotic arm;
- at least one of the joints comprising a motor having a motor axle, the motor axle being configured to rotate an output axle via a gear, where the dynamic model defines a relationship between forces acting on the robotic arm and resulting accelerations of the robotic arm;
- and
- wherein the at least one controller is configured to obtain a stiffness of the gear by performing operations comprising:
- applying torque to the motor axle using the motor;
- obtaining an angular position of the motor axle;
- obtaining an angular position of the output axle;
- and
- determining the stiffness of the gear based on at least the angular position of the motor axle, the angular position of the output axle, and the dynamic model, where the dynamic model defines a relationship between forces acting on the robotic arm and resulting accelerations of the robotic arm.
A system comprising a robotic arm, the system comprising:
- joints in the robotic arm;
- at least one controller to control the joints based on a dynamic model of the robotic arm, where the dynamic model defines a relationship between forces acting on the robotic arm and resulting accelerations of the robotic arm;
- each of the joints comprising a motor axle, the motor axle being configured to rotate an output axle using a gear;
- and
- wherein the at least one controller is configured to obtain a stiffness of each gear of each joint by performing operations comprising:
- applying torque to the motor axle using the motor;
- obtaining an angular position of the motor axle;
- obtaining an angular position of the output axle;
- and
- determining the stiffness of the gear based on at least the angular position of the motor axle, the angular position of the output axle, and the dynamic model, where the dynamic model defines a relationship between forces acting on the robotic arm and resulting accelerations of the robotic arm.
Dependencies are inferred from the claim text.