Robotic Camera Positioning System for Inspection of Tunnels: A Conceptual Design

Abstract

A robotic camera positioning system to aid in the image capture process of the photogrammetric inspection of hydroelectric tunnels is introduced. The system is designed to adapt to tunnels of different and non-constant diameters while providing consistent and high-quality image properties. The system captures high resolution images of the interior surfaces of tunnels to create a detailed 3D model allowing for the remote inspection and monitoring of a tunnel’s visual and spatial condition.The system is based on a three-wheeled mobile platform with an extendable boom capable of reaching the center of cylindrical tunnels up to 10 meters in diameter. An extending arm with a high resolution camera at each end rotates about the center of the tunnel, capturing images of the tunnel surface. The system provides the remote operator with pose and progress information through the incorporation of various sensors. It addresses the limited access many hydroelectric tunnels have with a modular design capable of being compacted, allowing for easy transport of components.Insight into the features and functionality of the system’s design is detailed, including the conceptual design and how it addresses the various objectives and constraints. Models constructed have been simulated in the process to gather kinematic and dynamic properties which provide means for component selection and model verification.The design has been developed in alliance with an industry partner with validated experience with photogrammetric inspection of such environments who is confident the proposed design will make a significant improvement to the efficiency, applicability, and ease of the image capture process.