Date of Graduation

2016

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Thomas Evans

Committee Co-Chair

Aaron Noble

Committee Member

Edward Sabolsky

Abstract

Interaction with asteroid bodies is an important component of the upcoming NASA Asteroid Redirect Mission (ARM) and further space exploration. To provide in-situ material identification for exploration objectives, two robotic nondestructive testing (NDT) systems titled the Impact Sensor (IS) and Robotic UPV were proposed. The IS device is based on the impact hammer NDT approach. While an impact hammer relies solely on a rebound value, analysis was conducted to determine if impact force-time histories could provide similar information. The IS prototypes consisted of impact mechanisms, as well as; a force torque sensor (FTS) and 7 degree of freedom (7-DOF) robotic manipulator---two components slated for robotic exploration missions. The first IS prototype, titled the IS-1; was designed to retrieve impact centric metrics. Two prototype iterations---the IS-1 and IS-2---were designed, tested, and evaluated in this work. Due to parameters inherent to the selected FTS and impact mechanism, IS-1 test results did not display material correlations. However, analysis of IS-1 results provided the guidelines for a second prototype. The IS prototypes were tested on analog materials to gather force-time metrics and create material correlations. The robotic integration of the UPV system (robotic UPV system) involved creating suitable attachments to integrate UPV transducers with 7-DOF robotic manipulators. The robotic UPV design consisted of Proceq's Pundit PL-200 UPV system with FTS and robotic manipulators. The testing focused on evaluating operational parameters and system integration using precise robotic placement. Specifically, robotic UPV testing analyzed effects from transducer force, transducer alignment, transducer type, transducer angular offset, and specimen length. Each robotic UPV test was conducted with concrete specimen varying from 1-6m length. For both NDT systems the proof-of-concept was confirmed. From IS-2 test results, correlations between material and force-time history metrics were observed. In addition, correlations were observed between robotic UPV magnitude and the transducer force, transducer type, transducer angular offset, and beam length variables. From IS-2 and robotic UPV test results, operational parameters were suggested for both systems. With continued advancements, both robotic NDT systems show promising capability to meet space exploration objectives.

Download

Share

COinS