Mobile Robot-Assisted Material Handling in Prefabricated Housing Factories

The prefabricated housing industry in the U.S. aims to relieve the shortage of affordable housing by manufacturing housing components off-site and assembling them on-site to increase project time efficiency and reduce the total cost. However, the industry still heavily depends on human work, and lacks of automation due to its cost-conscious nature. To find a proper way to introduce automation to the current labor-intensive manufacturing process, I first visited two prefabricated housing factories in the northeast U.S. to take a deeper look into their manufacturing process and material flow to find a proper task that can be automated. Based on the site visits, adding financial and practical considerations, the thesis proposes a system that uses mobile robots to assist with the material handling tasks. The solution includes robot hardware design and material transport strategy, algorithms of pathfinding/line-following, and collision avoidance methods. Due to the complexity of the project and the nature of this as a research thesis, the solution does not aim to deliver a complete, market-ready solution, but a proof of concept of a mobile robot-assisted material handling system able to handle materials of various sizes, plan the shortest path between stops, and agilely navigate in the narrow factory space without colliding with obstacles and pedestrians. The outcomes include a physical robot that passes the maneuverability test and a virtual simulation that puts all components together to prove the viability of the system. Finally, the thesis discusses the limitations of the project and opens up discussion on the possible future directions for refining the system.¹