Stiffness and temporal optimization in periodic movements: An optimal control approach

We present a novel framework for stiffness and temporal optimization of periodic movements, with an emphasis on exploiting the intrinsic passive dynamics to realize efficient actuation and control. We use a dynamical systems based representation tuned to the requirements of rhythmic movements and propose a systematic methodology to optimize for control commands, temporal aspect of movements and time-varying stiffness profiles from first principles of optimality. Evaluations on a single pendulum and underactuated two-link robot simulation highlight the benefits, achieving remarkable actuation efficiency on complicated, highly dynamic tasks such as swing-up and brachiation.