Browse Topic: Planning / scheduling
Achieving noise reduction in rotorcraft requires an analysis of various design parameters and flight conditions. However, high-fidelity methods are computationally expensive. To overcome this limitation, reduced order model (ROM)-based surrogate models have been applied to aerodynamics and aeroacoustics prediction. This study proposes a ROM-based surrogate model employing a variational autoencoder (VAE) to predict rotor aerodynamic loads and associated noise. Train and test datasets were generated using reformulated vortex particle method across a wide range of flight conditions. The proposed framework was applied to a single rotor, and its performance was evaluated qualitatively and quantitively in comparison with proper orthogonal decomposition (POD)-based surrogate model. The results show that VAE-based model consistently outperformed the POD model in noise prediction. These results demonstrate that the proposed framework enables accurate rotor noise prediction under various flight conditions and provides a promising approach for low-noise rotorcraft design and operational planning.
Time-Sensitive Networking (TSN) is an emerging technology that has garnered popularity among the US DoD and others for its deterministic properties while using flexible, ubiquitous Ethernet as its core. However, individual TSN devices will support the TSN features of only some of the vast array of amendments and extensions that make up the full IEEE 802 TSN standards. This functional and modular approach offers great flexibility, but it also increases the complexity of network planning, analysis, verification, etc. as well as potentially leading to unexpected emergent behavior that must be addressed before a TSN network can be truly said to be qualified for use with safety-critical systems. Using industry experience gained certifying other deterministic networks to DO-254 and DO-178C Design Assurance Level A (DAL-A) and applying it to the analysis, testing, and validation of a deterministic TSN Ethernet digital backbone offers a roadmap for overcoming these challenges. Such an approach must seek to satisfy the three basic building-blocks of 1) Device-Level Standards Conformance, 2) System-Level Performance and Interoperability, and 3) Network Composability and Determinism.
Previous work documented the use of IVHMS data on the U.S. Army's fleet of UH-60 Black Hawk helicopters to update the fatigue lives of six specific components on the A/L and M models. This paper documents a significant expansion of the level of data applied to the usage spectrum, as well as applying it to all components on the aircraft. As a design spectrum for the yet to be fielded Improved Turbine Engine (ITE) equipped UH-60M, changes due to new engine capability needed to be addressed. The new spectrum has been developed and is being used for planning of flight testing. The spectrum along with flight test loads will be used to generate fatigue lives for the new aircraft. Once deployed for several years the spectrum will be reviewed to determine if any changes are needed. This work highlights what the Army considers to be the most significant issues when applying monitored usage to critical fatigue components, and rationale for dealing with issues such as insufficient data for various purposes.
A new method for rapidly planning and dynamically replanning low noise rotorcraft flight operations has been developed and is discussed. A large database of rotorcraft maneuver segments is generated, and an acoustic cost is assigned to each segment by using a computationally efficient semiempirical rotorcraft noise modeling method that accurately models the changes in rotor noise caused by maneuvering flight. Combinatoric optimization techniques are then employed to combine these maneuver segments into a low noise optimal flight path. A simple heuristic for estimating the total acoustic cost required to reach the target location is developed and incorporated into the search algorithm, allowing the computation of low noise paths in seconds. A procedure for implementing an "anytime" version of the method is described, enabling feasible solutions to be dynamically replanned "on the fly"—i.e., in fractions of a second—and refined over time to a low noise optimal solution.
ABSTRACT The paper presents quantitively the range of challenges that attend the S-70i Black Hawk start production - from prototype building to serial production. This article focuses not only on engineering tasks however partially also describes challenges connected to the following areas: business, quality, logistic, manufacturing planning and organization, ground and flight testing, pilots and mechanics training and jobs, PR activity. The volume of presented information are regulated and limited by the ITC regulations and IP protections.
ABSTRACT This paper focuses on the problem of payload transportation by a flock of rotary-wing vehicles. The flock includes several aerial vehicles and a cable-suspended load that has to be transported from an initial position to a goal position in an a priori known environment. The development of several novel techniques including a detailed modeling of the quadrotor dynamics, a control architecture, and a dedicated motion planning algorithm based on a modified Rapidly-Explored Random Tree (RRT) method for the flock are presented in this paper. The proposed system modules were checked in different cluttered environments and under different circumstances and uncertainties. Monte-Carlo simulations were conducted as well in order to assess the performance of the planning approach.
The EUROPA planning system is a general-purpose, reusable, artificial intelligence software system for automatically generating plans for performing complex activities in parallel, in accordance with constraints on activities and their interactions. One part of the system input is a domain model, which describes the subsystems in question, their possible activities, and the associated constraints. The other part is a plan request, consisting of a set of activities and constraints among them. Given these two inputs, the system will try to find a complete plan that allows all aspects of the plan request to be done, while satisfying the constraints specified in the domain model. This functionality includes the capability of verifying that a plan satisfies all constraints. The system is designed to allow different techniques to be used to complete or verify plans.
ABSTRACT This paper extends the author's prior effort to provide a framework for fair, early, and meaningful assessment of rotorcraft fatigue durability. In this paper a comprehensive set of fatigue load spectra have been characterized for a conventional military rotorcraft and provided for potential future use by the reader. The author's method of mixed-Weibull parameterization has been improved over the prior method. Mixed-Weibull parameterization allows grouping of various sets of load paths as well as analytical comparison of the distributions. This paper includes an assessment of sensitivity to changes in airspeed limitations at altitude, as well as an assessment of sensitivity to human influence during mixed-Weibull parameterization. Once standardized mission spectra are established, they will prove useful in fatigue life specification verification, preliminary and detailed design, and structural test planning.
This document defines a set of standard application layer interfaces called JAUS Mission Spooling Services. JAUS Services provide the means for software entities in an unmanned system or system of unmanned systems to communicate and coordinate their activities. The Mission Spooling Services represent the platform-independent capabilities commonly found across all domains and types of unmanned systems. At present, 1 service is defined in this document (more services are planned for future versions of this document): Mission Spooler: Stores mission plans, coordinates mission plans, and parcels out elements of the mission plan for execution The Mission Spooler service is described by a JAUS Service Definition (JSD) which specifies the message set and protocol required for compliance. The JSD is fully compliant with the JAUS Service Interface Definition Language [JSIDL].
Lunar Mapper (LM) is a Web-based software that allows visualization of lunar spatial data layers acquired from lunar missions and other sources. The data includes imagery, digital elevation models, resource maps, and model output. LM is accessed using standard Web browsers and uses open-source tools and libraries. The data is stored on remote servers and viewed by the LM Web client. LM allows creation of project files to save user-specific data for future retrieval and collaboration.
This paper describes a guidance algorithm for autonomous operation in partially known environments. The emphasis of the paper is enabling learning within a receding horizon trajectory optimization framework. The information acquired from an exteroceptive sensor is assimilated into a spatial value function. This setup has the advantage that the system learns information directly relevant to optimal guidance and control behavior and enables efficient trajectory-planning in unknown or partially known environments. The system's performance is demonstrated using successive runs in high-fidelity indoor simulations.
The paper describes the use of an Intelligent Decision-aiding Agent (IDA) associate for management of distributed aviation assets during warfighter net-centric operations. VELOXITI, Inc. (formerly Applied Systems Intelligence, Inc.), is collaborating with government personnel to demonstrate and evaluate a Situational Awareness Fusion Enhancement (SAFE) Aid in a man-in-the-loop experimentation environment as part of an Aviation Development Directorate - Applied Aviation Technology Directorate (ADD-AATD) Phase II Small Business Innovative Research (SBIR) project. Last year’s Phase I focus was on defining the requirements for integrating a collaborative adaptive tasking system (CATS) into a full mission simulation environment. This year’s efforts have grown into the SAFE Aid Intelligent Decision-Aiding Associate (IDA) system which incorporates a platform agnostic Intelligent Associate System for scout/attack/utility helicopters, and which will be integrated, demonstrated and evaluated in an operationally relevant man-in-the-loop simulation environment. SAFE Aid is intended to dramatically increase situational awareness within the cockpit and allow the ability to identify and access multiple Surveillance and Reconnaissance assets with a single bezel button to automatically task manned and unmanned assets. This tasking is based upon prioritization of Area of Operations (AO) events that optimizes all Surveillance and Reconnaissance assets to cover high priority events in the AO. SAFE Aid also enables aircrew safe route planning functionality, collision avoidance, predictive aircraft positioning, over the horizon weather updates, and many other operationally relevant functionality for scout/reconnaissance/attack/utility helicopter missions including MEDEVAC support. This paper will show the development, integration, demonstration and evaluation of the SAFE Aid technology that reduces aircrew workload and enables aircrews to effectively manage and utilize distributed aviation assets, without impairing their operational performance on other flight tasks. Aircrews will fly operationally relevant mission vignettes in a laboratory simulation environment with SAFE Aid operating and without SAFE Aid operating. Data collection and analysis of aircrew responsiveness will assess the aircrew’s ability to optimize interaction between manned and unmanned aircraft within a relevant mission context environment. Mission safety will be demonstrated using the ability for the system to incorporate additional knowledge bases adapted to accommodate evolving Tactics, Techniques and Procedures (TTPs). Mission demonstrations will involve multiple aircrews operating in two simultaneous mission simulation environments. Operational effectiveness and situational awareness requirements will consider data and user interfaces, real-time performance and human interaction issues. These defined requirements will aid in documenting the evaluation criteria for the SAFE Aid IDA. Evaluation criteria consider collection and analysis of the measurements for both a simulator-based environment and for full flight environments. The ultimate goal is to identify IDA benefits for aircrew members when the SAFE Aid system is operating, as compared to when the system is not operating, and the impact this has on operationally relevant mission scenario success.
ABSTRACT Autonomous helicopters are required to fly at a wide range of speed close to ground and eventually land in an unprepared cluttered area. Existing planning systems for unmanned rotorcrafts are capable of flying in unmapped environments, however they are restricted to a specific operating regime dictated by the underlying planning algorithm. We address the problem of planning a trajectory that is computed in real time, respects the dynamics of the helicopter, and keeps the vehicle safe in an unmapped environment with a finite horizon sensor. We have developed a planning system that is capable of doing this by running competing planners in parallel. This paper presents a planning architecture that consists of a trajectory executive - a low latency, verifiable component - that selects plans from a planner ensemble and ensures safety by maintaining emergency maneuvers. Here we report results with an autonomous helicopter that flies missions several kilometers long through unmapped terrain at speeds of upto 56 m/s and landing in clutter. In over 6 months of flight testing, the system has avoided unmapped mountains, popup no fly zones, and has come into land while avoiding trees and buildings in a cluttered landing zone. We also present results from simulation where the same system is flown in challenging obstacle regions - in all cases the system always remains safe and accomplishes the mission. As a result, the system showcases the ability to have a high performance in all environments while guaranteeing safety.
In the early 1990s, NASA was planning for an extended stay on Mars, and scientists at Ames Research Center were concentrating efforts on creating a complete ecological system to sustain human crew-members during their time on the Red Planet. The group started looking at maximizing energy efficiency and alternative methods to make power on a planet that is millions of miles from Earth. They turned to a hybrid concept combining two renewable sources: wind and solar power technologies. Large surface temperature swings on Mars produce windy conditions; extreme examples are the frequent dust storms that can block nearly all sunlight.
STAMPS simulates either three- or six-degree-of-freedom cases for all spacecraft flight phases using translated HAL flight software or generic GN&C models. Single or multiple trajectories can be simulated for use in optimization and dispersion analysis. It includes math models for the vehicle and environment, and currently features a “C” version of shuttle onboard flight software. The STAMPS software is used for mission planning and analysis within ascent/descent, rendezvous, proximity operations, and navigation flight design areas.
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