Browse Topic: Computer simulation
ABSTRACT V-shaped hulls for vehicles, to mitigate buried blast loads, are typically formed by bending plate. Such an approach was carried out in fabricating small test articles and testing them with buried-explosive blast load in Southwest Research Institute’s (SwRI) Landmine Test Fixture. During the experiments, detailed time dependent deflections were recorded over a wide area of the test article surface using the Dynamic Deformation Instrumentation System (DDIS). This information allowed detailed comparison with numerical simulations that were performed with LS-DYNA. Though in general there is good agreement on the deflection, in the specific location of the bends in the steel the agreement decreases in the lateral cross section. Computations performed with empirical blast loads developed by SwRI and by more computationally intensive ALE methods in LS-DYNA produced the same results. Computations performed in EPIC showed the same result. The metal plate was then bent numerically so
ABSTRACT In this paper, we discuss a neuroimaging experiment that employed a mission-based scenario (MBS) design, a new approach for designing experiments in simulated environments for human subjects [1]. This approach aims to enhance the realism of the Soldier-task-environment interaction by eliminating many of the tightly-scripted elements of a typical laboratory experiment; however, the absence of these elements introduces several challenges for both the experimental design and statistical analysis of the experimental data. Here, we describe an MBS experiment using a simulated, closed-hatch crewstation environment. For each experimental session, two Soldiers participated as a Commander-Driver team to perform six simulated low-threat security patrol missions. We discuss challenges faced while designing and implementing the experiment before addressing analysis approaches appropriate for this type of experimentation. We conclude by highlighting three example transition pathways from
ABSTRACT A detailed methodology employing a system model of a tracked vehicle with a gun turret is used to analyze the stresses and loads applied to the gun mount as a result of gun firing events. The vehicle system model combines a Virtual Lab.Motion model of the tracked vehicle and gun mount which includes track super element, flexible gun mount body, and a beam element representation of the gun and gun tube sleeve coupled with a MATLAB/Simulink model of the hydraulic/pneumatic recoil system and gun pointing control system. This coupled system model with flexible components is needed for this analysis to determine the portion of the impulse that results in gun mount deformation. A brief overview of the vehicle system model, a detailed description of the gun mount model, and analysis of the gun mount loads and stress is included
ABSTRACT This paper describes next generation modeling tools to solve a basic problem of concept analysis, which is the lack of component models that realistically estimate the performance of technology that has yet to be fully reduced to specific products. Three important classes of electric power components essential to future Army vehicles are addressed: integrated electric machines, battery energy storage, and traction motor drives. Behavior models are delivered in a common software simulation “wrapper” with a limited number of user settings that allow the ratings of the component to be scaled to the performance required by the vehicle concept represented in a larger simulation. This approach captures expert knowledge about components so the systems engineer managing the concept analysis can create reliable simulations quickly
ABSTRACT The objective is to develop a human-multiple robot system that is optimized for teams of heterogeneous robots control. A new human-robot system permits to ease the execution of remote tasks. An operator can efficiently control the physical multi-robots using the high level command, Drag-to-Move method, on the virtual interface. The innovative virtual interface has been integrated with Augmented Reality that is able to track the location and sensory information from the video feed of ground and aerial robots in the virtual and real environment. The advanced feature of the virtual interface is guarded teleoperation that can be used to prevent operators from accidently driving multiple robots into walls and other objects
ABSTRACT Teleoperated ground vehicles are an integral part of the U.S. Army and Marine Corps long range vision and a key transition technology for fully autonomous vehicles. However, the combination of marginally-stable vehicle dynamics and limited perception are a key challenge facing teleoperation of such platforms at higher speeds. New technologies for enhancing operator perception and automatically detecting and mitigating rollover risk are needed to realize sufficient safety and performance in these applications. This paper presents three rollover mitigation concepts for high speed teleoperation of heavy tactical vehicles, including model-predictive warning, negative obstacle avoidance, and reactive brake controls. A modeling and simulation approach was used to evaluate these concepts within the Autonomous Navigation Virtual Environment Laboratory (ANVEL). Vehicle models for both the M1078 cargo truck and RG-31 MRAP were used throughout concept evaluation over terrain ranging from
ABSTRACT Rubber tracks are now extremely competitive for vehicles up to 50 tons and fully fielded on 39 ton vehicles. They represent the best of what technology can offer for tracked vehicles, in terms of high durability, performance and low life cycle cost. This is mainly attributed to the optimization through the five (5) technological tools described in this paper. Better from its numerous distinctive advantages, rubber tracks can be adapted to suit virtually any specific need. This ductile rubber track technology can be shaped to match today’s requirements, with the help of advanced rubber compounding and computer simulations
ABSTRACT This paper develops a linear closed form equation as required for automatic plowing depth control of a mine clearing combat vehicle. The vehicle will be tasked with using its Mine Clearing Blade (MCB) to remove surface laid and buried land mines on undulating terrain so that other vehicles can follow its path without the threat of mines. Blade control must be automatic to ensure that the target depth of the cleared path is achieved and all mines on the path are removed. A closed form solution for real-time computing relating the MCB motion and hydraulic actuator movement is developed and implemented. The equations are provided in symbolic form so that the dimensions of the mechanism can be directly substituted and/or modified without re-derivation. Results were verified with field measured data and implemented in the controller of a real vehicle to successfully achieve objective goal of Automatic Mine Clearing
ABSTRACT Parametric analysis is an essential step in optimizing the performance of any system. In robotic systems, however, its usability is often limited by the lack of complex yet repeatable experiments required to gather meaningful data. We propose using the Robotics Interactive Visualization and Experimentation Toolbox (RIVET) in order to perform parametric analysis of robotic systems
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 Computational models are widely used in the prediction of occupant injury responses and vehicle structural performance of ground vehicles subjected to underbody blasts. Although these physics based computational models incorporate all the material and environment data, the classic models are typically deterministic and do not capture the potential variations in the design, testing and operating parameters. This paper investigates the effect of one such variation in physical tests, namely, variations in the position of occupant setup on the occupant injury responses. To study the effects of occupant position, a series of vertical drop tower tests were performed in a controlled setup. A vertical drop tower test involves an Anthropomorphic Test Device (ATD) dummy positioned on a seat and the setup is dropped on an energy attenuating surface, thus producing a desired shock pulse on the seat structure. The experimental data was analyzed for sensitivity of occupant position and ATD
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