A Passive Upper Limb Exoskeleton for Macaques in a BMI Study: Kinematic Design, Analysis, and Calibration

Integrating an exoskeleton as an external apparatus for a brain-machine interface has the advantage of providing multiple contact points to determine body segment postures and allowing control to and feedback from each joint. When using macaques as subjects to study neural control of movement, a singularity-free upper limb exoskeleton is required to guarantee safe and accurate tracking of joint angles over all possible range of motion. In addition, the compactness of a design is of more importance considering macaques’ significantly smaller body dimensions than humans’. Proposed in this paper is a 6-degree-of-freedom (DOF) passive upper limb exoskeleton with 4 DOFs at the shoulder complex. System kinematic analysis is investigated in terms of its singularity and manipulability. A real-time data acquisition system is set up, and system kinematic calibration is conducted.