Robot system for lead-through programming

A robot system comprising a manipulator and a controller associated with the manipulator, wherein the controller supports impedance based control of a lead-through operation mode, wherein the controller is switchable between impedance based and admittance-based control of the lead-through mode;

• wherein a motor of the manipulator is adapted to receive a reference parameter from the controller, and the controller comprises a first control loop for sequentially outputting reference parameter values in a first one of impedance control and admittance control, and a second control loop for sequentially outputting reference parameter values in the other one of impedance control and admittance control, wherein, when switching from the first one to the other one of impedance-based control and admittance-based control, the second control loop is initialized to output, as a reference parameter value of a first iteration after switching, a value that differs by not more than a predetermined amount from the value output by the first control loop in a last iteration before switching.

A method for controlling a robot system in lead-through mode, the robot system having a manipulator and a controller, in which method a user guides a movement of a mobile portion of the manipulator to a target position, comprising:

• a) the controller supporting an initial phase of the movement under impedance control, and
• b) the controller supporting a final phase of the movement under admittance control, wherein the impedance control is used for teaching the robot system a long-haul part of a movement of the manipulator so as to be in general proximately to a target position, and wherein a final short-haul part of the movement in which the target position must be reached more precisely is accomplished under admittance control.