  Currently, commercially available intelligent transport robots that are
capable of carrying up to 90kg of load can cost \$5,000 or even more. This
makes real-world experimentation prohibitively expensive and limits the
applicability of such systems to everyday home or industrial tasks. Aside from
their high cost, the majority of commercially available platforms are either
closed-source, platform-specific or use difficult-to-customize hardware and
firmware. In this work, we present a low-cost, open-source and modular
alternative, referred to herein as "ROS-based Open-source Mobile Robot
($ROMR$)". $ROMR$ utilizes off-the-shelf (OTS) components, additive
manufacturing technologies, aluminium profiles, and a consumer hoverboard with
high-torque brushless direct current (BLDC) motors. $ROMR$ is fully compatible
with the robot operating system (ROS), has a maximum payload of 90kg, and costs
less than \$1500. Furthermore, ROMR offers a simple yet robust framework for
contextualizing simultaneous localization and mapping (SLAM) algorithms, an
essential prerequisite for autonomous robot navigation. The robustness and
performance of the $ROMR$ were validated through real-world and simulation
experiments. All the design, construction and software files are freely
available online under the GNU GPL v3 licence at
https://doi.org/10.17605/OSF.IO/K83X7. A descriptive video of $ROMR$ can be
found at https://osf.io/ku8ag.
