Method of obtaining vibrational properties of robot arm

A method of controlling a robot arm, where the robot arm comprises robot joints connecting a base and a tool flange, where each of the robot joints comprises an output flange that is movable in relation to a body of a corresponding robot joint and a motor configured to move the output flange in relation to the body, and where the method comprises:

• generating a target motion for the robot arm;
• obtaining vibrational properties comprised of a natural frequency and damping ratio of the robot arm;
• generating a control signal for the robot arm based on the target motion and the vibrational properties, the control signal comprising control parameters for motors of the robot joints;
• and
• controlling the motors based on the control signal;
• wherein the vibrational properties of the robot arm are obtained based on an inertia-vibration model for the robot arm, wherein the inertia-vibration model defines the vibrational properties of the robot arm as a function of an inertia of the robot arm, and wherein the inertia-vibration model is based on vibrational properties of the robot arm obtained for different physical configurations of the robot arm.

A robot controller for controlling a robot arm, wherein the robot arm comprises a plurality of robot joints connecting a robot base and a robot tool flange, wherein each of the robot joints comprises:

• an output flange movable in relation to a robot joint body;
• and
• a joint motor configured to move the output flange in relation to the robot joint body;
• wherein the robot controller is configured to control the robot arm based on an inertia-vibration model of the robot by executing operations comprising:
• generating a target motion for the robot arm;
• obtaining vibrational properties comprised of a natural frequency and damping ratio of the robot arm;
• generating a control signal for the robot arm based on the target motion and the vibrational properties, the control signal comprising control parameters for motors of the robot joints;
• and
• controlling the motors based on the control signal;
• wherein the vibrational properties of the robot arm are obtained based on an inertia-vibration model relating to the robot arm, wherein the inertia-vibration model defines the vibrational properties of the robot arm as a function of the inertia of the robot arm, and wherein the inertia-vibration model is based on the vibrational properties of the robot arm obtained for different physical configurations of the robot arm.