A flexible link manipulator as a force measuring and controlling unit

A position and force control concept for a manipulator with elasticity in joints and links is developed. The measurement of the link deformations is used for control of vibrations as well as for determining of contact forces. Two cases are distinguished: for fast movements on a contact surface, a multistage approach is applied that consists of an offline feedforward branch and an online elasticity controller; and for slow compliant movements, an impedance control algorithm is used that includes elasticity feedback to damp vibrations of the elastic links. A three-DOF (degree-of-freedom) manipulator with two links that are elastic with respect to bending and torsion is used for verification of the concept in experiments