Browse Topic: Mathematical models
ABSTRACT This paper presents a novel adaptive sampling method using intelligent UAVs in battlefields to help soldiers with awareness of environments. A UAV can perform as a robotic wingman in soldier formations, compensating for that cannot be scouted by soldiers, even being exposed to enemy fire. With portable size, the UAV is easily carried and flown for scouting tasks anytime. The flexibility of UAVs makes it possible to collect measurements sequentially. Each measurement is adaptively designed and determined from the Bayesian perspective to increase the fidelity of battlefields. Wavelet structure is considered to optimize measurement projections to substantially reduce the number of measurements based on compressive sensing framework. More specifically, each measurement is optimized by maximizing the posterior variance inferred from existing informative data. A motion planning algorithm for UAVs is designed based on the distribution of optimal measurements, striking a balance
ABSTRACT Machinery health management is becoming increasingly important and the diagnosis of failures based on machinery condition has been analyzed in-depth in the last few decades, and is relatively well understood. However, prognostic evaluation of faults in a machine is a harder task that involves predicting impending faults in the system and determining remaining useful life of the machinery. A survey of algorithms, and a detailed description of a hybrid CBM prognostic techniques being investigated for use in ground vehicle systems will be presented. The system incorporates a number of techniques to process and analyze the current condition of a ground vehicle, and to generate a prognosis for each subsystem in the vehicle. The discussion will describe a means of testing, verifying and iteratively improving prognostic capabilities throughout the lifecycle of the platform
ABSTRACT The dynamic simulation of multibody tracked vehicles offers engineers a powerful tool with which they may analyze and design. Currently, parts of these complex mechanisms are introduced to multibody algorithms as rigid bodies. Then in a follow-on structural analysis, the loads from the multibody dynamic simulation are input to calculate strains and stresses within the bodies. The present investigation aims to establish appropriate means by which flexible three-dimensional track links, which allow large relative rotation between the elements, can be modeled. This will pave the way towards the incorporation of detailed flexible structural models into a multibody dynamic simulation environment allowing for an integrated solution. In addition, a new formulation for the interaction between the rigid sprocket teeth and flexible chain is presented. Numerical results are introduced to illustrate the effects of flexible links on the dynamics of tracked vehicles
ABSTRACT A methodology based on a combination of commercial software tools is developed for rendering complex acoustic scenes in real time. The methodology aims to bridge the gap between real time acoustic rendering algorithms which lack important physics for the exterior urban environment and more rigorous but computationally expensive geometric or wave-based acoustics software by incorporating pre-computed results into a real time framework. The methodology is developed by surveying the best in class commercial software, outlining a general means for accommodating results from each, and identifying areas where supplemental capability is required. This approach yields a real time solution with improved accuracy. Strengths and limitations in current commercial technologies are identified and summarized
ABSTRACT The IGVC offers a design experience that is at the very cutting edge of engineering education, with a particular focus in developing engineering control/sensor integration experience for the college student participants. A main challenge area for teams is the proper processing of all the vehicle sensor feeds, optimal integration of the sensor feeds into a world map and the vehicle leveraging that world map to plot a safe course using robust control algorithms. This has been an ongoing challenge throughout the 26 year history of the competition and is a challenge shared with the growing autonomous vehicle industry. High consistency, reliability and redundancy of sensor feeds, accurate sensor fusion and fault-tolerant vehicle controls are critical, as even small misinterpretations can cause catastrophic results, as evidenced by the recent serious vehicle crashes experienced by self-driving companies including Tesla and Uber Optimal control techniques & sensor selection
ABSTRACT The age of large autonomous ground vehicles has arrived. Wherever vehicles are used, autonomy is desired and, in most cases, being studied and developed. The last barrier is to prove to decision makers (and the general public) that these autonomous systems are safe. This paper describes a rigorous safety testing environment for large autonomous vehicles. Our approach to this borrows elements from game theory, where multiple competing players each attempt to maximize their payout. With this construct, we can model an environment that as an agent that seeks poor performance in an effort to find the rare corner cases that can lead to automation failure
ABSTRACT Connected and automated vehicles (CAVs) leverage onboard sensing and external connectivity using Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I) and Vehicle-to-Everything (V2X) technologies to "know" the upcoming operating environment with some degree of certainty, significantly narrowing prior information gaps. These technologies have been traditionally developed and used for driver assistance and safety but are now being used to operate the vehicle more efficiently [1–5]. The eco-driving algorithm, which leverages the data available through these streams, performs two key functions: (1) acceleration smoothing and (2) eco-approach and departure (Eco-AND) at signalized intersections. The algorithm uses information from neighboring vehicles and signalized intersections to calculate an energy-efficient speed trajectory. This paper presents the development of an Android-based driver advisory application that leverages cellular Internet connectivity and Traffic
ABSTRACT Model based design techniques are being used increasingly to predict vehicle performance before building prototype hardware. Tools like ADAMS and Simulink enable very detailed models of suspension components to be developed so vehicle performance can be accurately predicted. In creating models of vehicle systems, often there is a question about how much component detail or model fidelity is required to accurately model system performance. This paper addresses this question for modeling shock absorber performance by comparing a low fidelity and high fidelity shock absorber model. A high fidelity and low fidelity mathematical model of a shock absorber was developed. The low fidelity shock absorber model was parameterized according to real shock absorber hardware dimensions. Shock absorber force vs. velocity curves were calculated in Simulink. The results from the low fidelity and high fidelity model were compared to shock absorber force vs. velocity test results. New vehicle
ABSTRACT This research proposes a human-multirobot system with semi-autonomous ground robots and UAV view for contaminant localization tasks. A novel Augmented Reality based operator interface has been developed. The interface uses an over-watch camera view of the robotic environment and allows the operator to direct each robot individually or in groups. It uses an A* path planning algorithm to ensure obstacles are avoided and frees the operator for higher-level tasks. It also displays sensor information from each individual robot directly on the robot in the video view. In addition, a combined sensor view can also be displayed which helps the user pin point source information. The sensors on each robot monitor the contaminant levels and a virtual display of the levels is given to the user and allows him to direct the multiple ground robots towards the hidden target. This paper reviews the user interface and describes several initial usability tests that were performed. This research
ABSTRACT To improve robustness of autonomous vehicles, deployments have evolved from a single intelligent system to a combination of several within a platoon. Platooning vehicles move together as a unit, communicating with each other to navigate the changing environment safely. While the technology is robust, there is a large dependence on data collection and communication. Issues with sensors or communication systems can cause significant problems for the system. There are several uncertainties that impact a system’s fidelity. Small errors in data accuracy can lead to system failure under certain circumstances. We define stale data as a perturbation within a system that causes it to repetitively rely on old data from external data sources (e.g. other cars in the platoon). This paper conducts a fault injection campaign to analyze the impact of stale data in a platooning model, where stale data occurs in the car’s communication and/or perception system. The fault injection campaign
ABSTRACT This presentation will review the ongoing lessons learned from a joint Industry/DoD collaborative program to explore this area over the past 5 years. The discussion will review the effectiveness of integrating multiple new technologies (combined with select COTS elements) to provide a complete solution designed to reduce spares stockpiles, maximize available manpower, reduce maintenance downtime and reduce vehicle lifecycle costs. A number of new and emerging technology case studies involving diagnostic sensors (such as battery health monitors), knowledge management data accessibility, remote support-based Telematics, secure communication, condition-based software algorithms, browser-based user interfaces and web portal data delivery will be presented
ABSTRACT Geotechnical site characterization is the process of collecting geophysical and geospatial characteristics about the surface and subsurface to create a 3-dimensional (3D) model. Current Robot Operating System (ROS) world models are designed primarily for navigation in unknown environments; however, they do not store the geotechnical characteristics requisite for environmental assessment, archaeology, construction engineering, or disaster response. The automotive industry is researching High Definition (HD) Maps, which contain more information and are currently being used by autonomous vehicles for ground truth localization, but they are static and primarily used for navigation in highly regulated infrastructure. Modern site characterization and HD mapping methods involve survey engineers working on-site followed by lengthy post processing. This research addresses the shortcomings for current world models and site characterization by introducing Site Model Geospatial System
ABSTRACT The study describes the development of a plug-in module of the realistic 3D Digital Human Modeling (DHM) tool RAMSIS that is used to optimize product development of military vehicle systems. The use of DHM in product development has been established for years. DHM for the development of military vehicles requires not only the representation of the vehicle occupants, but also the representation of equipment and simulation of the impact of such equipment on the Warfighter. To simulate occupants in military vehicles, whether land or air based, realistically, equipment must become an integral part of the extended human model. Simply attaching CAD-geometry to one manikin’s element is not sufficient. Equipment size needs to be scalable with respect to anthropometry, impact on joint mobility needs to be considered with respect to anatomy. Those aspects must be integrated in posture prediction algorithms to generate objective, reliable and reproducible results to help design engineers
ABSTRACT We have developed techniques for a robot to compute its expected myopic gain in performance from asking its operator specific questions, such as questions about how risky a particular movement action is around pedestrians. Coupled with a model of the operator’s costs for responding to inquiries, these techniques form the core of a new algorithm that iteratively allows the robot to decide what questions are in expectation most valuable to ask the operator and whether their value justifies potentially interrupting the operator. We have performed experiments in simple simulated robotic domains that illustrate the effectiveness of our approach
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