Design and analysis of a wrist-hand manipulator for rehabilitation of upper limb dexterous function

Dexterous distal arm functions are crucial for execution of activities of daily living (ADLs). However, it remains difficult for patients with neurological deficits, such as stroke, to recover the lost manipulation capabilities. In this paper, a modular approach has been proposed to design a wrist-hand manipulator to be employed in the rehabilitation training of the upper limb dexterous function. Consisting of the installation module, the forearm module, the in-parallel wrist module, and the hand module, the end-effector based manipulator encourages the patient to voluntary coordinate motion of individual joints of the upper limb. Further, it is compact, stiff, and can be easily installed on desk, wall or other systems. Various hand modules can be attached on the manipulator for patients of different paretic levels. Parameter optimization has been performed for the in-parallel wrist module about workspace capability and manipulability. Condition number over the entire workspace is taken as the manipulability measure. Finally, the design and optimization parameters are validated by kinematic simulation with MATLAB/Simulink SimMechanics toolbox.