Mechanism/Robot Design

Robotic designs use open and closed chain mechanisms to transmit motion from the actuators to an end-effector. Studies focus on kinematics, dynamics, and synthesis of such mechanisms.

Parallel Actuated Robots

Cover of Kinematics, Dynamics, and Design of Machinery textbook

Kinematics, Dynamics, and Design of Machinery, Third Edition, discusses techniques for mechanism design, chiefly rational synthesis and kinematic analysis. It presents a fresh approach to the topic and is suitable for graduate and senior undergraduate students.

Schematic of an S-R-U chain actuated by 7 cables
Screw Theory: S-R-U chain actuated by 7 cables

Several of the designs in our lab incorporate cable-driven systems, which pose unique design challenges. Part of our work involves developing new methods for the design and optimization of these systems in order create reliable devices that interact well with human subjects.

Schematics of the proposed 3-RRS parallel mechanism, along with CAD of the final design
3-RRS Parallel Mechanism in the Neck Brace

The underlying architecture is 3-RRS mechanism, as shown in Fig. 1. One can regard this mechanism as a perturbation from the well-known 3-RRS spherical mechanism, where all revolute axes intersect at a point, resulting the end-effector performs a spherical motion.  Since the motion of a human head is not purely spherical, the 3-RRS wrist cannot deliver the desired motion. Thus, we modified the spherical mechanism by separating the intersecting points into three, one for each chain. In this case, the end-effector obtains a motion with coupled rotation and translation.

Female subject wearing the RoSE
RoSE prototype designed for female adolescents

The RObotic Spine Exoskeleton is a two-layer Stewart platform, each layer consisting of a six degree-of-freedom spatial parallel mechanism.