Abstract: Disclosed are a robot arm having high back-drivability to interact with a human being, which is safely stopped, and a method of controlling the robot arm. When the operation of the robot arm having high back-drivability to interact with a human being is converted into a safety mode due to the occurrence of an emergency, in which the operation of the robot arm is stopped, only a torque having a degree to compensate for gravity applied to the robot arm, i.e., only a torque to maintain the kinematical position of the current state of the robot arm without falling of the robot arm due to gravity, is outputted to control the robot arm as if the robot arm is in a weightless state, thus being capable of safely stopping the robot arm. Thereby, a user can easily move the robot arm and thus safely escape from the robot arm, and it is possible to prevent the falling of the robot arm due to gravity and thus to protect devices of the robot arm and peripheral environment around the robot arm.

Abstract: Disclosed are a robot, which performs cooperative work with a plurality of robot manipulators through impedance control, and a method of controlling cooperative work of the robot. The method includes calculating absolute coordinate positions of end effectors, respectively provided at a plurality of manipulators to perform the work; calculating a relative coordinate position from the absolute coordinate positions of the end effectors; calculating joint torques of the plurality of manipulators using the relative coordinate position; and controlling the cooperative work of the plurality of manipulators according to the joint torques.