Document Type


Date of Award


Degree Name

Master of Science in Mechanical Engineering - (M.S.)


Mechanical and Industrial Engineering

First Advisor

Lu Lu

Second Advisor

Xianlian Alex Zhou

Third Advisor

Zhiming Ji


This thesis's scope was to construct a highly back drivable and compact joint design that can be used for wearable exoskeletons specifically designed to assist with rehabilitation. A compact cycloidal gear transmission was designed to satisfy the compactness requirement while ensuring the minimum torque is required for backdriving the mechanism. The joint was designed based on the compact cycloidal drive specifications, and the backdrivability test was performed to measure the minimum torque required (1.20 Nm) to backdrive. The joint design incorporates various important features such as rotation lock feature to prevent hyperextension, a housing design that offers the benefit of using the joint for the left and right limb, a motor mount that securely holds a brushless DC motor, and a sensor bracket that securely positions a control sensor over the motor for controlling the motor position and speed. Successful evaluation of the 3D printed prototype validated the integrity of the design.