Flexible Supervised Autonomy for Exploration in Subterranean Environments

While the capabilities of autonomous systems have been steadily improving in recent years, these systems still struggle to rapidly explore previously unknown environments without the aid of GPS-assisted navigation. The DARPA Subterranean (SubT) Challenge aimed to fast track the development of autonomous exploration systems by evaluating their performance in real-world underground search-and-rescue scenarios. Subterranean environments present a plethora of challenges for robotic systems, such as limited communications, complex topology, visually-degraded sensing, and harsh terrain. The presented solution enables long-term autonomy with minimal human supervision by combining a powerful and independent single-agent autonomy stack, with higher level mission management operating over a flexible mesh network. The autonomy suite deployed on quadruped and wheeled robots was fully independent, freeing the human supervision to loosely supervise the mission and make high-impact strategic decisions. We also discuss lessons learned from fielding our system at the SubT Final Event, relating to vehicle versatility, system adaptability, and re-configurable communications.Comment: Field Robotics special issue: DARPA Subterranean Challenge, Advancement and Lessons Learned from the Final

Operational Performance and Reliability, Availability and Maintainability Analysis Model (OPRAM) Development

693JJ621F000046Transportation Technology Center, Inc. (MxV Rail) conducted a project for the Federal Railroad Administration (FRA) to complete the development of Operational Performance and Reliability, Availability, and Maintainability (RAM) Analysis (OPRAM\uf8ea) tool. The team successfully developed the OPRAM software tool according to the objectives established in the scope of the project along with the associated documentation and training. The software is easy to install and operates as a standalone application in a desktop environment. Railroads can use the OPRAM software tool to assist in decision-making in defining when and where to deploy new methods of train control, per the Higher Reliability and Capacity Train Control (HRCTC) Program (i.e., Enhanced Overlay Positive Train Control (EO-PTC), Quasi-Moving Block (QMB) and Full Moving Block (FMB)). This support is provided by a direct comparison of different deployment options, prioritizing incremental enhancements of these train control methods as they become available, and evaluating and comparing potential RAM enhancement options

Measurement of Railway Track Geometry: A State-of-the-Art Review

The worldwide increase in frequency of traffic for passenger trains and the rise of freight trains over the recent years necessitate the more intense deployment of track monitoring and rail inspection procedures. The wheel-rail contact forces, induced by the static axle loads of the vehicle and the dynamic effects of ground-borne vibration coming from the track superstructure, have been a significant factor contributing to the degradation of the railway track system. Measurements of track irregularities have been applied since the early days of railway engineering to reveal the current condition and quality of railway lines. Track geometry is a term used to collectively refer to the measurable parameters including the faults of railway tracks and rails. This paper is aiming to review the characteristics of compact inertial measurement systems (IMUs), their components, installation, the basic measures of the quality of the track using motion sensors, like accelerometers, gyroscopes and other sensing devices mounted on different places of the vehicle. Additionally, the paper briefly discusses the fundamentals of inertial navigation, the kinematics of the translational and rotational train motions to obtain orientation, velocity and position information

Aerial Robotic Solution for Detailed Inspection of Viaducts

The inspection of public infrastructure, such as viaducts and bridges, is crucial for their proper maintenance given the heavy use of many of them. Current inspection techniques are very costly and manual, requiring highly qualified personnel and involving many risks. This article presents a novel solution for the detailed inspection of viaducts using aerial robotic platforms. The system provides a highly automated visual inspection platform that does not rely on GPS and could even fly underneath the infrastructure. Unlike commercially available solutions, our system automatically references the inspection to a global coordinate system usable throughout the lifespan of the infrastructure. In addition, the system includes another aerial platform with a robotic arm to make contact inspections of detected defects, thus providing information that cannot be obtained only with images. Both aerial robotic platforms feature flexibility in the choice of camera or contact measurement sensors as the situation requires. The system was validated by performing inspection flights on real viaducts.Unión Europea H2020-2019-769066Unión Europea H2020-2020- 87154

Critical Speed Analysis of Railcars and Wheelsets on Curved and Straight Track

The railway train running along a track is one of the most complex dynamic systems in engineering. Its operation has two main features: motion in a train of vehicles, and guidance by adhesion with the track. Kinematic analysis of railway vehicles and wheelsets facilitates the evaluation of the relative motion between the many vehicles in the train and the motion between the train and the track. This thesis explores the kinematics of the dynamic system of the train running along a track using basic physical principles. Engineers can use this understanding to calculate speed limits for established rail lines and calculate angles and distances that are of fundamental interest in the design of new train components and track. This work presents the derivation of the kinematic behavior of railcars and railway wheelsets on both curved and straight track and looks at how these motions change on inclines, or grades. It then explores how the kinematic equations are affected by industrial parameters such as locomotive speed, tonnage, track geometry, and railcar dimensions, resulting in a more complete picture of how individual variables factor into the overall kinematics of a running locomotive. The work ultimately discusses how this parametric analysis of kinematic derivations can shed light on current industrial problems of traffic flow optimization

Super-Resolution Restoration of MISR Images Using the UCL MAGiGAN System

High spatial resolution Earth observation imagery is considered desirable for many scientific and commercial applications. Given repeat multi-angle imagery, an imaging instrument with a specified spatial resolution, we can use image processing and deep learning techniques to enhance the spatial resolution. In this paper, we introduce the University College London (UCL) MAGiGAN super-resolution restoration (SRR) system based on multi-angle feature restoration and deep SRR networks. We explore the application of MAGiGAN SRR to a set of 9 MISR red band images (275 m) to produce up to a factor of 3.75 times resolution enhancement. We show SRR results over four different test sites containing different types of image content including urban and rural targets, sea ice and a cloud field. Different image metrics are introduced to assess the overall SRR performance, and these are employed to compare the SRR results with the original MISR input images and higher resolution Landsat images, where available. Significant resolution improvement over various types of image content is demonstrated and the potential of SRR for different scientific application is discussed

Characterization of the Earth\u27s surface and atmosphere for multispectral and hyperspectral thermal imagery

The goal of this research was to develop a new approach to solve the inverse problem of thermal remote sensing of the Earth. This problem falls under a large class of inverse problems that are ill-conditioned because there are many more unknowns than observations. The approach is based on a multivariate analysis technique known as Canonical Correlation Analysis (CCA). By collecting two ensembles of observations, it is possible to find the latent dimensionality where the data are maximally correlated. This produces a reduced and orthogonal space where the problem is not ill-conditioned. In this research, CCA was used to extract atmospheric physical parameters such as temperature and water vapor profiles from multispectral and hyperspectral thermal imagery. CCA was also used to infer atmospheric optical properties such as spectral transmission, upwelled radiance, and downwelled radiance. These properties were used to compensate images for atmospheric effects and retrieve surface temperature and emissivity. Results obtained from MODTRAN simulations, the MODerate resolution Imaging Spectrometer (MODIS) Airborne Sensor (MAS), and the MODIS and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) (MASTER) airborne sensor show that it is feasible to retrieve land surface temperature and emissivity with 1.0 K and 0.01 accuracies, respectively

NADIR AND OBLIQUE UAV PHOTOGRAMMETRY TECHNIQUES FOR QUANTITATIVE ROCK FALL EVALUATION IN THE RIMROCKS OF SOUTH-CENTRAL MONTANA

As our cities expand into geologically sensitive areas across the greater Rocky Mountain region and beyond, quantitative methods of assessment are increasingly critical for the development of evidence-based alternatives to avoid or mitigate geologic hazards. Unmanned Aerial Vehicle (UAV) photogrammetry can improve these geologic investigations by enabling remote visual inspection, measurement, and spatial analysis while eliminating many of the physical access limitations that contribute to field sampling bias and human error. UAV photogrammetry technology was employed to evaluate fragmental rock fall hazards at two locations in the Rimrocks region of south-central Montana, Zimmerman Trail Road and Phipps Park. At these sites, active retrogressive rock slope instability caused by differential erosion has produced damaging rock fall. Nadir and oblique imagery of the 35-acre Zimmerman Trail Road and 13-acre Phipps Park study areas was acquired with a DJI Phantom 4 Pro UAV and processed into digital photogrammetry with Pix4Dmapper. Remote methods of analysis were employed to measure the orientation of discontinuities in rock fall source areas and to quantify rock fall susceptibility. At Zimmerman Trail Road, photogrammetry data products were used to numerically differentiate rock fall hazard zones along the 0.3-mile long rock slope in accordance with the detailed Rock Fall Hazard Rating System (Pierson, 1991). At Phipps Park, photogrammetry was used to measure the size, run out distance, and change in elevation of high energy rock fall and to generate 2D and 3D slope profiles, which were used to model potential future rock fall. The methods and findings demonstrate how nadir and oblique UAV photogrammetry can be used to implement quantitative, defensible approaches for evaluating rock fall susceptibility and run out potential in geologic investigations of fragmental rock fall hazard areas