Noncollocated passive transfer functions for a flexible link robot

In this article, we apply the concept of passivity to control the position of a one-link flexible robot using the input torque at the base. Since the choice of the tip position as an output leads to a nonpassive transfer function, we propose a new choice for the output, namely, the noncollocated output measurement consisting of the angle of rotation at the hub augmented with a weighted value of the angle of rotation of the link´s extremity. A technique for determining the closest output to the tip resulting in a passive transfer function is given