Hand movement strategies in telecontrolled motion along 2-D trajectories

The authors evaluate the performance and try to identify the strategies of human operators (HOs) teleoperating a robot along 2-D-trajectories in simulations of place-like tasks in an obstacle encumbered environment. The experiments utilize computer graphic simulations of a remote robot whose end-effector displacements are dynamically controlled in the X-Y plane by the HO´s hand displacements. The performance is described in the various displayed conditions in terms of movement duration, spatial and temporal errors, and energy. The data show that performance depends on the nature of the cues and instructions provided to the operators. Comparative analysis of the various conditions suggests that visual feedback position control is used when continuous static or dynamic information about the trajectory is provided, while feedforward control, corrected by sampled visual information, is adopted when a self-generated movement can be planned and executed. The data also show that for a given set of execution cues, equivalent performance is achieved in both visual frames of reference