Admittance control for physical human-robot interaction

This paper presents an overview of admittance control as a method of physical interaction control between machines and humans. We present an admittance controller framework and elaborate control scheme that can be used for controller design and development. Within this framework, we analyze the influence of feed-forward control, post-sensor inertia compensation, force signal filtering, additional phase lead on the motion reference, internal robot flexibility, which also relates to series elastic control, motion loop bandwidth and the addition of virtual damping on the stability, passivity and performance of minimal inertia rendering admittance control. We present seven design guidelines for achieving high performance admittance controlled devices that can render low inertia, while aspiring coupled stability and proper disturbance rejection.