Computational fluid dynamics at NASA Ames and the numerical aerodynamic simulation program

Computers are playing an increasingly important role in the field of aerodynamics such as that they now serve as a major complement to wind tunnels in aerospace research and development. Factors pacing advances in computational aerodynamics are identified, including the amount of computational power required to take the next major step in the discipline. The four main areas of computational aerodynamics research at NASA Ames Research Center which are directed toward extending the state of the art are identified and discussed. Example results obtained from approximate forms of the governing equations are presented and discussed, both in the context of levels of computer power required and the degree to which they either further the frontiers of research or apply to programs of practical importance. Finally, the Numerical Aerodynamic Simulation Program--with its 1988 target of achieving a sustained computational rate of 1 billion floating-point operations per second--is discussed in terms of its goals, status, and its projected effect on the future of computational aerodynamics

Lunar material transport vehicle

The proposed vehicle, the Lunar Material Transport Vehicle (LMTV), has a mission objective of efficient lunar soil material transport. The LMTV was designed to meet a required set of performance specifications while operating under a given set of constraints. The LMTV is essentially an articulated steering, double-ended dump truck. The vehicle moves on four wheels and has two identical chassis halves. Each half consists of a chassis frame, a material bucket, two wheels with integral curvilinear synchronous motors, a fuel cell and battery arrangement, an electromechanically actuated dumping mechanism, and a powerful microprocessor. The vehicle, as designed, is capable of transporting up to 200 cu ft of material over a one mile round trip per hour. The LMTV is capable of being operated from a variety of sources. The vehicle has been designed as simply as possible with attention also given to secondary usage of components

Implementation of automated assembly

Research has shown that about 60 - 80% wealth producing activities is related to manufacturing in major industrial countries. Increased competition in industry has resulted in a greater emphasis on using automation to improve productivity and quality and also to reduce cost. Most of the manufacturing works such as machining, painting, storage, retrieval, inspection and transportation have changed to automation successfully, except assembly. Manual assembly is predominant over automatic assembly techniques due to inherent assembly problem and the fact that the assembly machines lack the innate intelligence of human operator and lack sufficient flexibility to changeover when product designs and market demands change. With the advent of flexible manufacturing systems, which involve very large capital costs and complex interactions. For the reduction the risk of the investment and analyze the system, simulation is a valuable tool in planning the systems and in analyzing their behavior, and get the best use of them. This thesis applies animation techniques to simulate an automatic assembly system. In chapter 1 to 9, we cover some of the fundamental concepts and principles of automatic assembly and simulation. Some manufacturers put the subject of part orientation first on their list of priorities; but design for assembly (DFA) techniques have proven extremely valuable in developing better assembly techniques and ultimately, better products. We discuss DFA in chapter 1, part feeding and orientation in chapter 2. Chapter 3, 4 and 5 are concerned with assembly process, machines and control system, respectively. Annual sales for industrial robots have been growing at the rate of about 25 percent per year in major industrial countries, we review the robot application in chapter 6. The cost of material handling is a significant portion of the total cost of production, material storage uses valuable space and consumes investment, we cover these two topics in chapter 7 and 8. Chapter 9 is concerned with simulation. In chapter 10, 11,12 and 13, we implement a software package IGRIP to build a model of an automatic assembly system and analyze the result

Dynamic Collaborative Multi-Agent Reinforcement Learning Communication for Autonomous Drone Reforestation

We approach autonomous drone-based reforestation with a collaborative multi-agent reinforcement learning (MARL) setup. Agents can communicate as part of a dynamically changing network. We explore collaboration and communication on the back of a high-impact problem. Forests are the main resource to control rising CO2 conditions. Unfortunately, the global forest volume is decreasing at an unprecedented rate. Many areas are too large and hard to traverse to plant new trees. To efficiently cover as much area as possible, here we propose a Graph Neural Network (GNN) based communication mechanism that enables collaboration. Agents can share location information on areas needing reforestation, which increases viewed area and planted tree count. We compare our proposed communication mechanism with a multi-agent baseline without the ability to communicate. Results show how communication enables collaboration and increases collective performance, planting precision and the risk-taking propensity of individual agents.Comment: Deep Reinforcement Learning Workshop at the 36th Conference on Neural Information Processing Systems (NeurIPS 2022

GRASP News Volume 9, Number 1

A report of the General Robotics and Active Sensory Perception (GRASP) Laboratory

Quantifying Surface Subsidence along US Highway 50, Reno County, KS using Terrestrial LiDAR

US-50 in Reno County, KS east of Hutchinson has undergone active deformation from ground subsidence. Subsurface karsting from salt dissolution is the main cause for this phenomenon. Two prominent sinkhole features occur in close proximity to one another and to the regionally mapped dissolution front of the Hutchinson Salt Member. Brandy Lake, which is a lake forming sinkhole, has undergone active subsidence along its western margin whereas the sinkhole at the Victory Road/US-50 intersection has had subsidence occur within the last 12 years. Using a Terrestrial Laser Scanning (TLS) approach, this study analyzes the geometry, magnitude and temporal nature of the active subsidence over these two sinkholes. Results show that the Brandy Lake sinkhole has an asymmetric subsidence geometry along the western margin of the lake with a deformed road area of 358 m and a magnitude of subsidence of 1.15 m. The Victory Road sinkhole is characterized by a symmetric bowl-shaped depression that is 125 m wide from west to east and 117 m wide from north to south with a magnitude of subsidence of 1.20 m. Both of the sinkholes exhibit no active change over the course of the study indicating that subsidence has temporarily ceased. These observations agree with the fact that subsidence is transient on the local scale but regionally controlled by the main dissolution front and subsurface structural lineaments

Non-Contact Torque Transfer Using Ferrofluid

Gearing systems are a mechanical based systems that allow an input shaft torque to increase or decrease when it is transferred as an output shaft. Although the gearing system is an old creation that holds little mysteries in the current day, the complexities used to adapt it to new applications continues to grow. The invention discussed and researched in this paper goes in depth on how the gearing system was redesigned to accommodate new uses along with making the system more efficient. A gearing system uses a solid surface to surface contact to transfer the torque from input to output. Overtime, the solid contact surface deteriorate due to friction and inefficiencies causing the destruction of the system in order to produce longer lasting gearing system that require less maintenance and reduce the wear within the system, a more efficient and durable process must be implemented. This paper discusses the redesign of the common gearing system referred to as the non-contact torque transfer using ferrofluid. The ferrofluid gearing system was created within the bounds specified by the sponsor, Dr. Nassersharif. It has been designed to outlast other gearing systems, making it appeal to the customer demand through implementing magnets and ferrofluid. Through calculations and physical observations, the ferrofluid gearing system proved to work and the design concept is able to be patented

Investigation of Combustion Phenomena in a Single-Cylinder Spark-Ignited Natural Gas Engine with Optical Access

More demanding efficiency and emissions standards for internal combustion (IC) engines require novel combustion strategies, alternative fuels, and improved after-treatment systems. However, their development depends on improved understanding of in-cylinder processes. For example, the lower efficiency of conventional spark-ignited (SI) natural-gas (NG) engines reduces their utilization in the transportation sector. Single-cylinder optical-access research engines allow the use of non-intrusive visualization techniques that study in-cylinder flow, fuel-oxidizer mixing, and combustion and emissions phenomena under conditions representative of production engines. These visualization techniques can provide qualitative and quantitative answers to fundamental combustion-phenomena questions such as the effects of engine design, operating conditions, fuel composition, fuel delivery strategy, and ignition techniques.;The thesis is divided in two main parts. The first part focuses on the setup of a single-cylinder research engine with optical access including the design of its control system and the acquisition of in-cylinder pressure data and high-speed combustion images. The second part focuses on measurements of the turbulent flame speed using the high-speed combustion images. Crank-angle-resolved images of methane combustion were taken with a high-speed CMOS camera at a rate of 15,000 Hz. The optical engine was operated in a skip-firing mode (one fired cycle followed by 5 motored cycles) at 900 RPM and a load of 5.93 bar IMEP. The images show that flow turbulence and flame stretch resulted in flame velocities several order of magnitude higher compared to the laminar flame velocity. In addition, both in-cylinder pressure and optical data were used to determine the cycle-to cycle variability of the combustion phenomena

Controlling Newcastle Disease in Village Chickens: A Field Manual

Livestock Production/Industries,

NASA Tech Briefs, November 1993

Topics covered: Advanced Manufacturing; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences