On the Equivalence of Direct Strain Feedback and Lumped Parameter Wave Echo Control for Oscillation Damping of Elastic-Link Arms

Abstract

The work discusses two control concepts. Both approach oscillation damping for elastic link robotic arms from fundamentally different theoretical directions. Despite their principal difference, the work consolidates both control schemes by mathematically deriving the equivalence of the resulting control laws. This letter demonstrates the practical application of the oscillation damping on a multi-elastic-link experimental setup. With a special emphasis on the influence of static deflections due to gravity, the letter finally compares the damping action as a modulation to the joint position, joint velocity, and joint motor current reference. The comparison leads to recommendations for strainbased oscillation damping of elastic-link arms under gravitational influence.