A kinematic mechanism of the thumb exoskeleton to help stroke victims in rehabilitation and is kinematically compatible with the human thumb. The thumb exoskeleton has the following unique features:
- an underlying kinematic mechanism that is optimized to achieve a large range of motion
- a design that actuates four degrees of freedom of the thumb
- a series elastic actuation based on a Bowden cable, allowing for bidirectional torque control of each thumb joint individually.
- CMC, MCP, and IP joint articulation through the full active range of motion in flexion and extension, while maintaining the abduction–adduction angle at the CMC joint;
- Full active range of abduction–adduction motion at the CMC joint while maintaining the position of the other joint angles;
- Full active range of flexion–extension and abduction–adduction motion in a circular pattern at the CMC joint;
- Full active range of flexion–extension motion at the MCP and IP joint while maintaining the position of the other joints.