Autonomous Ultrasonic Thickness Measurement by a Magnet-Wheeled Robot

A wireless sensing device recently developed by PI Wang’s group has demonstrated various structural sensing capabilities for bridge applications. In the meantime, a latest robot platform developed by Dr. La’s group at the University of Nevada, Reno (UNR) demonstrates promising performance navigating on steel bridge members. Marrying the two state-of-the-art developments, this project will produce a magnet-wheeled robot capable of autonomous nondestructive measurement on steel bridge structures. Both laboratory and field validations will be performed. Approach and Methodology: Earlier this year, Dr. H. M. La’s research group in the University of Nevada, Reno (UNR) developed a small robot that is suitable for climbing on steel bridge members. Using roller-chains embedded with magnets, the tank-like robot can self-adapt and climb on curved steel surfaces, and transit over sharp corners. The robot weighs a few kilograms and can carry 1 kg of payload, which is sufficient for additional hardware expected in this project. Maximum recorded speed is over 30 cm/s. The UNR team will provide the robot platform for wireless sensing development and testing by PI Wang’s group at Georgia Tech. Overall Objectives: This project will integrate advanced wireless sensing technologies to the UNR robot platform. At first, the functionality of ultrasonic thickness measurement will be developed on the mobile platform. The ultrasonic thickness measurement only requires access to one side of an object, and can achieve sub-millimeter accuracy. The technique can be used for corrosion and defect detection, e.g. on the web and flanges of an I-beam. In addition, vibration measurements will be added to the robotic platform as well; potential applications include tension estimation in steel strands of cable-supported structures. Scope of Work in Year 1: (1) Further advance the previously designed wireless sensing device for ultrasonic thickness measurement, (2) Design and test a push-pull mechanism for a transducer to be attached firmly on the surface of a steel member, and (3) Validate the performance of the wireless device on the robot platform for ultrasonic thickness measurement. Scope of Work in Year 2: (1) Investigation of various ultrasonic transducer types, in particular the Alpha Series transducers (2) increase of sampling frequency over tens of MHz is desired by developing a new Martlet wing which supports a high sampling rate, (3) integration with the UNR Robot for agility and maneuvering over complex terrains.