Robot Arm

A robot, comprising:

• a robot arm comprising a first arm segment and a second arm segment;
• a motor configured to move the second arm segment relative to the first arm segment;
• a yielding element configured to mechanically couple the first arm segment and the second arm segment;
• a sensor configured to determine a relative position of the first arm segment in relation to the second arm segment and to output a position sensor signal representing the relative position;
• and
• a control unit configured to receive the position sensor signal and to control the motor in accordance with the position sensor signal,
• wherein the control unit is further configured to control the motor such that the first arm segment is moved into a desired relative position in relation to the second arm segment, when no external force is applied to the robot arm, and when an external force is applied to the robot arm, the motor generates a counterforce which depends on the deviation between the actual position and the desired position, and
• wherein the control unit has a predetermined time constant, so that changes in the external force, which are rapid as compared to the time constant, are substantially absorbed by damping elements coupled between the first arm segment and the second arm segment.

A method for controlling a robot arm composed of a first arm segment and a second arm segment, the method comprising:

• determining a relative position of the first arm segment in relation to the second arm segment;
• and
• controlling the relative position of the first arm segment in relation to the second arm segment so as to move the first arm segment into a desired relative position when no external force is applied to the robot arm and to generate a counterforce which depends on the deviation between a currently determined position and a desired position, when an external force is applied to the robot arm,
• wherein controlling the relative position is done with a pre-determined time constant, so that changes in the external force, which are rapid as compared to the time constant, are substantially absorbed by damping elements coupled between the first arm segment and the second arm segment.