Asymptotically stable compliance control of redundant robots: A solution to the non-integrability problem of nullspace velocities

In this paper a compliance control law for kinematically redundant manipulators is proposed. The controller contains a Cartesian compliance part and a nullspace compliance part which are complemented by a power-conserving decoupling term. The approach deliberately avoids inertia shaping in order to obtain a control law which does not require the measurement of external forces and gets less sensitive to model uncertainties. Asymptotic stability of the closed loop system is shown by utilizing semi-definite Lyapunov functions.