CRAM It! A Comparison of Virtual, Live-Action and Written Training Systems for Preparing Personnel to Work in Hazardous Environments

In this paper we investigate the utility of an interactive, desktopbased virtual reality (VR) system for training personnel in hazardous working environments. Employing a novel software model, CRAM (Course Resource with Active Materials), we asked participants to learn a specific aircraft maintenance task. The evaluation sought to identify the type of familiarization training that would be most useful prior to hands on training, as well as after, as skill maintenance. We found that participants develop an increased awareness of hazards when training with stimulating technology – in particular (1) interactive, virtual simulations and (2) videos of an instructor demonstrating a task – versus simply studying (3) a set of written instructions. The results also indicate participants desire to train with these technologies over the standard written instructions. Finally, demographic data collected during the evaluation elucidates future directions for VR systems to develop a more robust and stimulating hazard training environment

Visuohaptic Simulation of a Borescope for Aircraft Engine Inspection

Consisting of a long, fiber optic probe containing a small CCD camera controlled by hand-held articulation interface, a video borescope is used for remote visual inspection of hard to reach components in an aircraft. The knowledge and psychomotor skills, specifically the hand-eye coordination, required for effective inspection are hard to acquire through limited exposure to the borescope in aviation maintenance schools. Inexperienced aircraft maintenance technicians gain proficiency through repeated hands-on learning in the workplace along a steep learning curve while transitioning from the classroom to the workforce. Using an iterative process combined with focused user evaluations, this dissertation details the design, implementation and evaluation of a novel visuohaptic simulator for training novice aircraft maintenance technicians in the task of engine inspection using a borescope. First, we describe the development of the visual components of the simulator, along with the acquisition and modeling of a representative model of a {PT-6} aircraft engine. Subjective assessments with both expert and novice aircraft maintenance engineers evaluated the visual realism and the control interfaces of the simulator. In addition to visual feedback, probe contact feedback is provided through a specially designed custom haptic interface that simulates tip contact forces as the virtual probe intersects with the {3D} model surfaces of the engine. Compared to other haptic interfaces, the custom design is unique in that it is inexpensive and uses a real borescope probe to simulate camera insertion and withdrawal. User evaluation of this simulator with probe tip feedback suggested a trend of improved performance with haptic feedback. Next, we describe the development of a physically-based camera model for improved behavioral realism of the simulator. Unlike a point-based camera, the enhanced camera model simulates the interaction of the borescope probe, including multiple points of contact along the length of the probe. We present visual comparisons of a real probe\u27s motion with the simulated probe model and develop a simple algorithm for computing the resultant contact forces. User evaluation comparing our custom haptic device with two commonly available haptic devices, the Phantom Omni and the Novint Falcon, suggests that the improved camera model as well as probe contact feedback with the 3D engine model plays a significant role in the overall engine inspection process. Finally, we present results from a skill transfer study comparing classroom-only instruction with both simulator and hands-on training. Students trained using the simulator and the video borescope completed engine inspection using the real video borescope significantly faster than students who received classroom-only training. The speed improvements can be attributed to reduced borescope probe maneuvering time within the engine and improved psychomotor skills due to training. Given the usual constraints of limited time and resources, simulator training may provide beneficial skills needed by novice aircraft maintenance technicians to augment classroom instruction, resulting in a faster transition into the aviation maintenance workforce

A novel cross-validated nondestructive evaluation framework for damage detection using acoustic emission

Developing Structural Health Monitoring (SHM) techniques for monitoring and evaluation in civil, mechanical and aerospace applications has a direct impact on public safety, primarily because it is related to reduced downtime and life extension of critical aging components and structures. Such trends are further fueled by the observed shift in modern inspection from "time-based" to "condition-based" maintenance approaches, which promise targeted evaluations when and exactly where they are needed. In this context, the objective of this dissertation is to develop a novel cross-validated framework of using acoustics-based methods for non-destructive testing & evaluation (NDT&E) with the ultimate goal to improve infrastructure condition assessment related primarily to the aerospace industry. This framework is called cross-validated as the primary NDT method of interest, the Acoustic Emission (AE) method, is used in conjunction with several other NDT methods including Guided Ultrasonic Waves (GUW), Digital Image Correlation (DIC) and Infrared Thermography (IRT). The proposed work is built therefore upon the idea of implementing a multimodal NDE approach including both novel hardware integration and data processing techniques that can mitigate existing challenges in reliably using AE in SHM applications. The advantage of designing reliable damage detectors is realized by integrating acoustic features with heterogeneous features that can provide complementary information on the initiation and development of damage. Several demonstrations in static and dynamic conditions of the proposed framework ranging from fundamental plasticity investigations to applied structural analysis are described to demonstrate the efficacy of the novel approach.Ph.D., Mechanical Engineering and Mechanics -- Drexel University, 201