An integrated UGV-UAV system for construction site data collection

There have been recent efforts to increase the degree of automation and frequency of data collection for construction applications using Unmanned Aerial/Ground Vehicles (UAV/UGV). However, the current practice of data collection is traditionally performed, which is manual, costly, time-consuming, and error-prone. Developing vision-based mobile robotic systems that are aware of its surrounding and capable of autonomous navigation are becoming essential to many construction applications, namely surveying, monitoring, and inspection. Nevertheless, the systems above suffer from a series of performance issues. One major problem is inefficient navigation in indoor and cluttered scenes with many obstacles and barriers, where some places are inaccessible by a UGV. To provide a solution to this problem, this paper designs a UAV-UGV team that integrates two custom-built mobile robots. The UGV autonomously navigates through space, leveraging its sensors. The UAV acts as an external eye for the UGV, observing the scene from a vantage point that is inaccessible to the UGV. The relative pose of the UAV is estimated continuously, which allows it to maintain a fixed location that is relative to the UGV. The key aspects for the development of this system that is capable of autonomous navigation are the localization of both UAV and UGV, mapping of the surrounding environment, and efficient path planning using multiple sensors. The proposed system is tested in an indoor and cluttered construction-like environment. The performance of the system demonstrates the feasibility of developing and deploying a robust and automated data collection system for construction applications in the near future.