A Robust Polyurethane Depositing System for Overcoming Obstacles in Disaster Scenario Robotics

Abstract

One of the most difficult challenges faced by ground robots operating in the aftermath of a disaster is the presence of uneven and unstable terrains; in these environments traditional locomotive systems struggle. In this work, a Polyurethane Foam depositing system is proposed to enable ground robots to overcome obstacles and navigate challenging substrates with relative ease. The proposed system is inexpensive, can be added onto existing platforms and enables autonomy via simple control systems. The final mechanical properties of the foam can be tuned in real-time and on board to adapt to different situational requirements. Four deposit foam types have been fully characterized, with volumetric expansion ratios ranging from 20× to 33×, compressive strengths from 0.16M P a to 2M P a and full expansion and set times below 6 minutes in all cases. To show that real-time operations are possible, the system has been implemented on a twotracked rover which was then able to accurately control the amount of deposited foam to form structures such as single and multilayered ramps and blocks. Thanks to this, the vehicle was able to autonomously overcome large objects and chasms that would have otherwise prevented operation.