Robotic diagnosis of directional force control performance at an end-effector of a limb toward physiotherapeutic support

This paper reports relations between force control performance and output direction at an end-effector of a limb when a human apply force to a rigid object. A highly backdrivable rehabilitation supporting system is used to provide an evaluation program. It is also used for repetitive force sensing. Measurement on twelve seated subjects can quantify force control accuracy when the subjects try to output 10 N to 8 directions which divide 360 degrees to each part of 45 degrees. The group of the subjects which includes young unimpaired persons and old paralyzed patients enrolls in several weeks of clinical test. Results are compared between each subject by introducing analysis methods to discuss the directional force control performance. The results in this paper quantitatively show the clinical empirical knowledge that the hemiplegic individuals have lower controllability in pushing direction than that in pulling direction.