Model Validation and Design for the Dynamic Environment Simulator. Phase 2

This paper examines the problem of simulating angular velocity fields that may for example, be experienced by a pilot during a supermaneuverable flight trajectory. The ability to simulate angular velocity fields has important applications in the study of certain physiological effects encountered by pilots during these unusual flight scenarios. The simulations are to be performed using a centrifuge simulator called the Dynamic Environment Simulator (DES) located in the Armstrong Laboratory of Wright-Patterson Air Force Base. Some of the kinematic issues relating to the motion control of the DES are examined in the paper. >

The ability to localize a virtual auditory source was evaluated under varying levels of sustained (+G2) acceleration. Participants were required to judge the locations of virtual auditory cues located along the horizontal plane (elevation 0°) during exposure to 1.0, 1.6, 2.5, 4.0, 5.6, and 7.0 +Gz. The experiment was conducted at the Air Force Research Laboratory's Dynamic Environment Simulator - a man-rated, three-axis centrifuge. No significant increases in localization error were found between 1.0 and 5.6 +Gz; however, a significant increase did occur at the 7.0 +Gz level. In addition, the percentage of reversals did not vary as a function of +Gz level. Collectively, these results indicate that one's ability to localize virtual auditory cues is well maintained at various levels of sustained acceleration.

This project is part of a research effort to design a hydrogen plant and its interface with a nuclear reactor. This project developed a dynamic modeling, simulation and optimization environment for nuclear hydrogen production systems. A hybrid discrete/continuous model captures both the continuous dynamics of the nuclear plant, the hydrogen plant, and their interface, along with discrete events such as major upsets. This hybrid model makes us of accurate thermodynamic sub-models for the description of phase and reaction equilibria in the thermochemical reactor. Use of the detailed thermodynamic models will allow researchers to examine the process in detail and have confidence in the accurary of the property package they use.

Differentiating responses of weather files and local climate change to explain variations in building thermal-energy performance simulations

: Females are now flying combat aircraft in the Air Force. Questions Of gender differences regarding adaptation and performance)in the high environment (9G) must be studied Scientifically. The Dynamic Environment Simulator, a three- axis centrifuge with closed-loop flight simulation, provides the laboratory to investigate the issues. Results. The eight women in this high-G performance study did not show cardiovascular adaptation to high whereas the eight men did. Both genders showed increased leg calf compliance indicating possible chronic vascular effects. No echocardiographic graphic evidence of heart damage was found The women demonstrated half the strength of the men, but displayed similar G tolerance and endurance. The women showed less oxygen desaturation of brain tissue than the men during high exposure. The women did not perform the simulated air-to-air combat sortie quite as well as the men, though there was no effect of menstrual cycle on their ability to complete the mission There was no effect of high exposure on the length Or the female monthly cycle, regardless of oral contraceptive use. Conclusion. Women demonstrated acceptable tolerance to and performance during simulated high aerial combat, without menstrual effect, even in light of their reduced muscular strength and cardiovascular adaptation as compared to men.

: In the past, laboratory simulators have, because of technical limitations, usually been restricted to reproduce isolated segments of the operational environment. The next generation of simulators will provide the ability to create the high-magnitude, complex accelerations of operational environments for exploration of the biomechanics, physiologic, and performance changes resulting from exposure of humans and animals to those environments. A six-degree-of-freedom motion device, operating in the 0-30 cps range to produce complex vibrations with peak loads up to plus or minus 15 g, a dynamic pressure chamber (that will create sound pressure fluctuations of up to 172 db in the 0- 100 cps frequency range), and a dynamic escape simulator (a sophisticated centrifuge) that will permit suprapositioning of sustained acceleration of up to 20 g's with high-magnitude, complex, angular and linear motion and a wide range of atmospheric pressures and temperatures are now under construction. A design study on a horizontal impact research device has been completed. The specific design characteristics and performance range of these devices are compared to the environments produced by operational conditions and to existing laboratory simulation facilities.

A colored traveling salesman problem (CTSP) is a path optimization problem in which colors are used to characterize diverse matching relationship between cities and salesmen. Namely, each salesman has a single color while every city has one to multiple salesmen’s colors, thus allowing salesmen to visit exactly once the cities of their colors. It is noteworthy that cities’ accessibilities to salesmen may change over time, which usually takes place in the multiwarehouse distribution of online retailers. This work presents a new CTSP with dynamically varying city colors for describing and modeling some scheduling problems with variable city accessibilities. The problem is more complicated than the previously proposed CTSP with varying edge weights. In particular, the solution feasibility changes as the cities change their colors, that is, a feasible original solution path may become no longer feasible after city colors change. A variable neighborhood search (VNS) algorithm is presented to solve the new problem. Specifically, a dynamic environment simulator with an adjustable frequency and amplitude is designed to mimic such color changes. Then, direct-route encoding, greedy initialization, and appropriate population immigrant are proposed to form an enhanced VNS, and then its performance is evaluated. The results of extensive experiments show that the proposed VNS can quickly track the environmental changes and effectively resolve the problem.

: Twenty-two student test pilots have participated in closed-loop tracking indoctrination runs on the Dynamic Environment Simulator. Each pilot flew through a series of profiles up to 6 G in both the conventional upright seat position and a 55 degrees tilt back seat position. The subjective responses and pilot questionnaires are presented.

In this paper, the locomotion and steering control of a simulated Mini Cheetah quadruped robot was investigated in the presence of terrain characterised by low friction. Low-level locomotion and steering control were implemented via a central pattern generator approach, whereas high-level steering control manoeuvres were implemented by comparing a neural network and a linear model predictive controller in a dynamic simulation environment. A data-driven approach was adopted to identify the robot model using both a linear transfer function and a shallow artificial neural network. The results demonstrate that, whereas the linear approach showed good performance in high-friction terrain, in the presence of slippery conditions, the application of a neural network predictive controller improved trajectory accuracy and preserved robot safety with different steering manoeuvres. A comparative analysis was carried out using several performance indices.

The key to the successful "factory of the future" will be the effective coordination of managerial functions and production operations. The research presented in this dissertation addresses this "coordination" issue, especially in terms of understanding the impact and possibilities which exist in an information-rich environment. Such an environment is often referred to in the literature as being a computer-integrated manufacturing (CIM) environment. An interactive simulation modeling program, MOSES (Manufacturing Organization Simulation and Evaluation System), was developed for the purpose of describing, analyzing, and understanding such manufacturing. MOSES is a copyrighted computer program, a menu-driven, interactive, simulation modeling tool. MOSES users are able to define the manufacturing environment to be simulated by keying in data values (e.g., products, bills of material, and production rates) which describe the organization. MOSES then uses these data values to "build the manufacturing simulation model." That is, once the manufacturing parameters have been defined, MOSES can simulate the manufacturing organization (from orders through distribution) without the user having to write any computer code or having to understand the principles of simulation modeling. MOSES users are then able to interact with the manufacturing organization as "managers" in the dynamic simulation environment. This interactive capability allows MOSES users to test various manufacturing scenarios, watch the model's progress from the perspectives of different organizational functions (e.g., from marketing or from production), override model-generated decisions (e.g., by changing the demand forecast), and view the results. The MOSES approach to simulation modeling differs from traditional approaches. In short, MOSES uses both mathematic and logical modeling principles, employs traditional simulation modeling techniques but in combination with database technology, and includes the user as an integral component in the simulation process.

• Developed dynamic models to simulate LFR-based nuclear propulsion systems. • Introduced the Ship-to-Shore concept, enabling clean energy transfer to ports. • Achieved significant CO 2 emission reduction: 24.5 kt/y during navigation. • Increased energy production by 697% through the Ship-to-Shore concept. • Provided a pathway for sustainable maritime propulsion aligned with IMO targets. This paper investigates the integration of IV generation small modular reactors into maritime vessels as a viable alternative to conventional fossil fuel-powered systems. To support maritime decarbonisation and evaluate the energy and economic performance of their onboard implementation, suitable mathematical models of energy systems powered by small modular reactors are developed. Among various nuclear technologies, a lead-cooled fast reactor (LFR) using mixed oxide fuel is modelled and implemented within a dynamic simulation environment. The model simulates the energy performance of a Helium Brayton cycle with a regenerator and reheating, powered by an LFR. This model can assess the temperature distribution of the lead coolant, the helium temperatures throughout the Brayton cycle, the generated mechanical and electrical power, thermodynamic efficiency, and waste heat. Following the development of the LFR-based model, it is integrated into a broader computational framework that enables the evaluation of the ship’s overall energy performance, including the energy demands of onboard utilities under different operating modes and climatic conditions. To demonstrate the potential of these systems, a LFR is simulated as a replacement for conventional fossil fuel engines onboard a containership. A representative route, reconstructed from real-time online data, is used to assess reactor performance under dynamic maritime conditions. Furthermore, a novel concept – ship-to-shore connection – is introduced, whereby surplus electricity produced by the onboard LFR is supplied to port grids, contributing to the decarbonisation of port facilities and surrounding areas. Simulation results indicate that small modular reactor systems could effectively nullify onboard fossil fuel consumption. For instance, avoided CO 2 emissions are estimated at 24.5 kt/y during navigation and 15.3 kt/y during port stays, including also emissions offset through the replacement of national thermoelectric power generation in ship-to-shore application. The implementation of the ship-to-shore connection concept results in an increase in energy production during port stays ranging from 572% to 697%, yielding substantial environmental and economic benefits.

Steady-state Optimality Analysis for Investigating the Energy Optimal Operation of Representative Natural Gas Liquefaction Cycles

This paper aims to propose an innovative method to obtain the traversability maps of unstructured environments and the best path between two points on the basis of the specific characteristics of the robots that has to perform a given mission. Taken in consideration a robot team that have to traverse an assigned terrain, the peculiar capabilities of each robot are underlined in a dynamic simulation environment and then embedded into a neural network finally used as a robot model for the generation of the traversability maps. On the basis of the obtained results, the best robot within the team (wheeled, legged, hybrid) can be selected. The proposed strategy, together with the obtained simulation results, are presented, carefully analyzed and then compared.

Disaggregate Analysis of the Inter-Building Effect in a Dense Urban Environment

This paper entails application of the energy shaping methodology to control a flexible, elastic Cosserat rod model. Recent interest in such continuum models stems from applications in soft robotics, and from the growing recognition of the role of mechanics and embodiment in biological control strategies: octopuses are often regarded as iconic examples of this interplay. Here, the dynamics of the Cosserat rod, modeling a single octopus arm, are treated as a Hamiltonian system and the internal muscle actuators are modeled as distributed forces and couples. The proposed energy shaping control design procedure involves two steps: (1) a potential energy is designed such that its minimizer is the desired equilibrium configuration; (2) an energy shaping control law is implemented to reach the desired equilibrium. By interpreting the controlled Hamiltonian as a Lyapunov function, asymptotic stability of the equilibrium configuration is deduced. The energy shaping control law is shown to require only the deformations of the equilibrium configuration. A forward-backward algorithm is proposed to compute these deformations in an online iterative manner. The overall control design methodology is implemented and demonstrated in a dynamic simulation environment. Results of several bio-inspired numerical experiments involving the control of octopus arms are reported.