The Robot Of Theseus: a modular robotic testbed for legged locomotion.

Area of Science:

• Robotics
• Biomechanics
• Comparative Morphology

Background:

• Quadrupedal robots often lack biomechanical relevance to animals due to significant morphological differences.
• High costs and limited customizability of existing robots hinder biological research.
• There is a need for adaptable robotic models to study locomotion and morphology.

Purpose of the Study:

• To present a low-cost, 3D-printable, and modular quadrupedal robot for biomechanical hypothesis testing.
• To enable researchers to match diverse animal morphologies and test locomotion hypotheses.
• To provide an open-source platform for custom gait and morphology development.

Main Methods:

• Developed the Robot Of Theseus (TROT), a quadrupedal robot built from 3D-printed parts and off-the-shelf components costing approximately $4000.
• Incorporated modular leg designs with options for 3 or 4 links, switchable femur-tibia joint orientations (knee/elbow), and adjustable link lengths via telescoping mechanisms.
• Utilized open-source software for user-defined gaits and morphological adaptations, with backdrivable motors for adjustable virtual spring stiffness and range of motion.

Main Results:

• Demonstrated TROT's utility in comparing locomotion across extant, extinct, and theoretical morphologies.
• Quantified the impact of morphological changes, finding a 29% increase in leg moment of inertia led to a 28.3% increase in Cost of Transport.
• Successfully used the platform for biomechanical hypothesis testing.

Conclusions:

• The Robot Of Theseus (TROT) offers a versatile, affordable, and customizable solution for biomechanical research.
• The modular design facilitates testing hypotheses related to morphology and locomotion.
• TROT has potential applications beyond biomechanics, including control strategy development and exploration.