Influence of planar manipulandum to the hand trajectory during point to point movement

We present the analysis of the planar manipulandum effects to the trajectory of point to point movements in horizontal plane. This analysis is of significance for the control of a haptic robot that can be used for the rehabilitation of hemiplegic patients. The effects were assessed by comparing data collected in experiments with healthy subjects when performing simple movements that are used in the therapy of stroke patients. We found significant differences between the preferred trajectories and the deviations from the preferred trajectories (p<0.01) when moving with and without the manipulandum. This result suggests that for the design of the controller of a robot assistant inertial properties of the robot mechanism must be considered even in the case that it is used only for the assessment (passive) or within the bio-feedback.