A Two-DOF Bipedal Robot Utilizing the Reuleaux Triangle Drive Mechanism

Abstract

This thesis explores the field of legged robots with reduced degree-of-freedom (DOF) leg mechanisms. Multi-legged robots have drawn interest among researchers due to their high level of adaptability on unstructured terrains. However, conventional legged robots require multiple degrees of freedom and each additional degree of freedom increases the overall weight and complexity of the system. Additionally, the complexity of the control algorithms must be increased to provide mobility, stabilization, and maneuvering. Normally, robotic legs are designed with at least three degrees of freedom resulting in complex articulated mechanisms, which limits the applicability of such robots in real-world applications. However, reduced DOF leg mechanisms come with reduced tasking capabilities, such as maintaining constant body height and velocity during locomotion.

To address some of the challenges, this thesis proposes a novel bipedal robot with reduced DOF leg mechanisms. The proposed leg mechanism utilizes the Reuleaux triangle to generate the foot trajectory to achieve a constant body height during locomotion while maintaining a constant velocity. By using a differential drive, the robot is also capable of steering. In addition to the analytical results of the trajectory profile of each leg, the thesis provides a trajectory function of the Reuelaux triangle cam with respect to time such that the robot can maintain a constant velocity and constant body height during walking. An experimental prototype of the bipedal robot was integrated and experiments were conducted to evaluate the walking capability of the robot. Ongoing future work of the proposed design is also outlined in the thesis.