In applications where the robot interacts with the environment it is crucial that the robot is aware of the contact forces. Unexpected forces may lead to sudden stops because of torque overload, or limited accuracy of the robot because of compliance in joints and links. These situations frequently arise when robots work in unstructured environments where the exact positions of objects are uncertain. They may also occur in structured environments. The reconfigurability of the robot can increase dramatically if the robot can be force controlled.
The most common solution is to equip the robot with an external force sensor. However, such sensors are expensive and may be difficult to integrate in a reliable way into the application. The Cognibotics alternative is to use only the internal sensors already available in the robot joint in order to estimate the external forces.