Dynamic balance of finitely stiff mechanisms: Balancing benefits and drawbacks

Fast-moving robots induce large dynamic reaction forces and moments at the base, resulting in disruptive vibrations and a loss of accuracy at the end-effector. By adding counter-masses and counter-inertias these shaking forces and moments may be reduced or even eliminated. However, current state-of-the-art approaches typically disregard the elasticity of the robot links, which potentially leads to undesirable parasitic dynamics, unbalance and loss of controller performance. In this article, the effect of link flexibility on the balance quality is investigated in a 2-DoF delta-type robot. It is demonstrated that a partial balancing solution accomplishes 80% shaking
force reduction without the loss of controller bandwidth.