Robot controlling device

A robot controlling device, comprising:

• an actuator to drive a drive shaft transferring a driving force to a joint shaft;
• a drive shaft angle detector to detect an angle of the drive shaft;
• a joint shaft angle calculator to calculate an angle of the joint shaft from the angle of the drive shaft;
• an endpoint position calculator configured to calculate an endpoint position of a robot from the angle of the joint shaft;
• a position commanded value generator configured to generate a position commanded value for the endpoint position;
• a position error calculator configured to calculate a position error, which is an error between the endpoint position and the position commanded value;
• a Jacobian matrix calculator configured to calculate a Jacobian matrix between an operational coordinate system of the robot and a joint coordinate system, on the basis of the angle of the joint shaft;
• a joint angle difference calculator configured to calculate a joint angle difference, from the position error and the Jacobian matrix, according to an inverse kinematics calculation;
• a torque commanded value calculator configured to calculate a torque commanded value by integrating the joint angle difference;
• a driver to drive the actuator on the basis of the torque commanded value;
• an external force calculator configured to calculate an external force applied to the endpoint position;
• a force commanded value generator configured to generate a force commanded value for the endpoint position;
• a force error calculator configured to calculate a force error which is an error between the external force and the force commanded value;
• a compliance model storage to store a compliance model for the endpoint position;
• a first correction amount calculator configured to calculate a first correction amount for the position commanded value, according to the force error, using the compliance model;
• and
• a second correction amount calculator configured to calculate a second correction amount for the position commanded value, on the basis of a first order lag compensation for the first correction amount,
• wherein the position error calculator calculates the position error using the second correction amount.