Analysis of pick-and-place, eating and drinking movements for the workspace definition of simple robotic devices

Current robotic devices for rehabilitation after stroke are often large and complex as they are conceived to train arbitrary movements in the 3D space. This paper analyzes the minimal requirements that the workspace of a robotic device should have in order to promote training of principal activities of daily living, considering the shoulder movement's limitations of subacute patients. Pick-and-place, drinking and eating movements of five healthy subjects were analyzed. In all these three tasks, approximately 82% of all trials deviate laterally less than 5% of the target distance and we recommend target distances of less than 40% of the arm length in order to minimize improper shoulder movements. The study can be applied for designing simpler, yet efficient robotic devices for rehabilitation of the upper limb or for constraining exercises on existing ones when dealing with stroke patients, especially for those prone to shoulder complications (e.g. subacute patients).