Dynamic analysis of simultaneous adaptation of force, impedance and   trajectory
  When carrying out tasks in contact with the environment, humans are found to concurrently adapt force, impedance and trajectory. Here we develop a robotic model of this mechanism in humans and analyse the underlying dynamics. We derive a general adaptive controller for the interaction of a robot with an environment solely characterised by its stiffness and damping, using Lyapunov theory. 
Yanan Li and Etienne Burdet
cs.RO