Flatness and Tracking

For the solution of the motion planning problem, all we required was the knowledge of a dynamical model and the time, in other words, anticipative data: the reference trajectory was computed from the present time to some future time according to what we know about the system’s evolution. This type of design is called open-loop. If the system dynamics is precisely known and if the disturbances (all signals not taken into account in the model that might affect the system’s evolution) don’t produce significant deviations from the predicted trajectories in the workspace, the open-loop design may sometimes be sufficient.