Collision Detection and Reaction for a Multi-Elastic-Link Robot Arm

In contrast to the common understanding of robot link elasticity as a detrimental effect the paper presents a novel approach to beneficially exploit the intrinsic link compliance for the detection and reaction to unpredicted collisions between the robot and its environment. The paper employs an inner loop controller to rapidly attenuate structural oscillations. Next, a linear relationship between the actuator joint torques as well as the damped link surface strains is derived to accurately model the residual dynamics. The model is identified for an experimental multi-elastic link robot arm under the influence of gravity. Experimental results are provided using a generalized momentum based technique for the detection and reaction to collisions with fragile objects placed on a force sensor as well as interactions with a human.