Method For Detecting A Collision Of A Robot Arm With An Object, And A Robot With A Robot Arm

A method for detecting a collision of a robot arm with an object, wherein the robot arm is a part of a robot that includes a plurality of serially arranged links mounted relative to respective axes, and position sensors assigned to the individual axes and provided for determining the positions of each two adjacent links relative to one another, wherein a tool center point is allocated to the robot arm and the robot further includes an electronic control device in communication with the position sensors, and drives controlled by the electronic control device for the automatic movement of the links of the robot arm relative to one another, the method comprising:

• automatically moving the links controlled by the electronic control device, such that the robot arm performs an actual movement associated with a target movement of the robot arm;
• during the actual movement of the robot arm with the electronic control device based upon the signals emitted by the position sensors, evaluating whether at least one invariant for the target movement of the robot arm is satisfied by the actual movement of the robot arm, based upon the actual poses and/or derived values of the actual poses of the links relative to one another, and/or based upon the actual position and/or at least one derived value of the actual position of the tool center point;
• and
• when the evaluation results in a non-satisfaction of the at least one invariant, then:
• indicating a collision of the robot arm with the object, and
• initiating of a safety function of the robot, controlled by the electronic control device.