Work Description

Date: 2024 August 9

Dataset Title: The Robot of Theseus (TROT) CAD models and print files

Dataset Creators: Karthik Urs, Jessica Carlson, Aditya Srinivas Manohar, Michael Rakowiecki, Abdulhadi Alkayyali, John E. Saunders, Faris Tulbah, Talia Y. Moore

Dataset Contact: Talia Moore taliaym@umich.edu

Funding: None

Key Points:
- We include STL models of all 3D printed parts needed to assemble TROT.
- We use PrusaSlicer to generate bed layouts of the PLA parts for each robotic leg linkage. These layouts are saved in 3MF print files.
- Note that each leg linkage will require either a 7.5:1 gear ratio planetary actuator or a 12:1 gear ratio planetary actuator.
- Please refer to the TROT Assembly Guide on the EMBiR Lab website for more information on assembly of TROT, including a list of non-3D-printed parts needed. https://www.embirlab.com/

Research Overview:
Robotic models are useful for independently varying specific features, but most quadrupedal robots differ so greatly from animal morphologies that they have minimal evolutionary relevance. Commercially available quadrupedal robots are also prohibitively expensive for biological research programs and difficult to customize. Here, we present a low-cost quadrupedal robot with modular legs that can match a wide range of animal morphologies for biomechanical hypothesis testing. The Robot Of Theseus (TROT) costs ≈$4000 to build out of 3D printed parts and standard off-the-shelf supplies. Each limb consists of 2 or 3 rigid links; the proximal joint can be rotated to become a knee or elbow. Telescoping mechanisms vary the length of each limb link. The open-source software accommodates user-defined gaits and morphology changes. Effective leg length, or crouch, is determined by the four-bar linkage actuating each joint. The backdrivable motors can vary virtual spring stiffness and range of motion.

Methodology:
Autodesk Inventor was used for CAD modeling of TROT. 3D printed parts were exported as STL files from Autodesk Inventor. Layout and orientation of parts on the print bed was achieved in PrusaSlicer and saved as 3MF print files.

Instrument and/or Software specifications:
We used Autodesk Inventor for CAD modeling of TROT parts and to export the parts to STL files. We used PrusaSlicer to slice and lay out the parts in a 3MF print file. We use an Original Prusa i3 MK3S+ to print parts in 0.75mm PLA. We use the Formlabs Preform slicer to slice and lay out parts for printing in the Formlabs High Temp Resin.

Files contained here:
The TROT Bill of Materials.xlsx provides the source and cost estimate of all off-the-shelf parts purchased for this robot.

The files are organized into a Planetary_Actuators folder, a Robotic_Linkages folder, and a Spine folder.

-Planetary_Actuators includes two subfolders and one separate file:
--7-5_1_GearRatio contains STL files and 3MF print files for the 7.5:1 gear ratio actuator. Note some parts must be printed in high temp resin and are therefore included only as STL files.
--12_1_Gear_Ratio contains STL files and 3MF print files for the 12:1 gear ratio actuator. Note some parts must be printed in high temp resin and are therefore included only as STL files.
--RI50_PLANETARY_HOUSING_DOUBLEFAN.stl is used as the resin planetary housing for both gear ratios.

-Robotic_Linkages includes three subfolders:
--Link_1 contains STL files and 3MF print files for the hip (uppermost linkage)
--Link_2 contains STL files and 3MF print files for the knee (middle linkage)
--Link_3 contains STL files and 3MF print files for the ankle (lowest linkage)

--Spine contains STL files and 3MF print files for the spine and spinal attachments of TROT

Related publication(s):
Urs, Carlson, Srinivas Manohar, Rakowiecki, Alkayyali, Saunders, Tulbah, Moore. (forthcoming) The Robot of Theseus: A modular robotic testbed for legged locomotion.

Use and Access:
Attribution - NonCommercial 4.0 International (CC BY-NC 4.0)

To Cite Data:
Urs, Carlson, Srinivas Manohar, Rakowiecki, Alkayyali, Saunders, Tulbah, Moore. The Robot of Theseus (TROT) CAD models and print files. (2024)