Development of a Tethered Mobile Robot for Highway Maintenance

This document reports on the development of the Tethered Mobile Robot (TMR) at the Advanced Highway Maintenance and Construction Technology (AHMCT) Center at the University of California, Davis. This application of automation has the primary objective of improving the level of safety of a variety of highway maintenance and construction activities.

The TMR system is a self-propelled wheeled mobile robot that works in close proximity to a support vehicle for purposes of power, etc. The robot’s position relative to the support vehicle is measured with high accuracy. As such, the support vehicle contains the associated maintenance supplies (sealant, etc.), power supply (hydraulic power supply, electrical generator, etc.), and in many cases, the primary maintenance operation sensing devices (e.g., machine vision for crack sealing operations) and/or path planning components.

The TMR project has involved the following: a detailed literature search, development of global machine specifications, development of system design concepts, and the design and construction of a downsized prototype TMR for the initial development of both the mechanical system and the required controls. This was followed with the evaluation of the first generation prototype, which led to the design and construction of a full-sized prototype TMR and relative position system. This report addresses each of the development aspects, and includes discussions of operational requirements, system configuration, system modeling, downsized system testing, control system architecture and approach, and test results of the full-size unit. Technical drawings are included as are control software listings. Finally, recommendations for further work are discussed.