Robot control device

A robot control device that controls a robot arm having an elastic mechanism between a rotation axis of a motor and a rotation axis of a link, and has an angular velocity control system that performs proportionality/integration control on an angular velocity of the motor and outputs a current command value to the motor,

• the robot control device comprising:
• an observer configured to receive the angular velocity of the motor and the current command value as inputs, have a nonlinear dynamic model of the robot arm, and estimate an angular acceleration of the link, an angular velocity of the link, and an angular velocity of the motor from a simulation model of an angular velocity control system of the motor subjected to proportionality/integration control using a gain equivalent to the angular velocity control system;
• a first feedback unit configured to calculate an axis torsion angular velocity from a difference between the angular velocity of the link estimated by the observer and the angular velocity of the motor estimated by the observer, and give feedback to the angular velocity control system;
• a second feedback unit that feeds back the angular acceleration of the link estimated by the observer to the angular velocity control system;
• and
• a first feedback constant calculating unit that compensates an end effector load mass and increases inertia at the second feedback unit when an end effector load in the nonlinear dynamic model has low inertia.