Browse Topic: Hardware
This paper describes the electromagnetic noise mitigation on the Maryland Tiltrotor Rig (MTR) and presents its first hover test results. The primary source of noise was found to be pulse width modulation associated with the motor controller. Due to this noise, testing was limited to unpowered, freewheeling cases. To solve the noise problem and allow powered testing, three hardware filters were integrated into the power and data systems. A complementary digital filter was also used. With the filtering solution in place, hover tests were carried out to high collectives of 30◦and blade loadings of 0.2. The test data was assessed using blade element-momentum theory predictions.
Low-level flight, defined by high-speed operations near terrain, represents a significant challenge in military rotorcraft missions while providing strategic advantages, such as radar evasion and heightened surprise. Recent conflicts highlight the urgent need for advanced low-level flight capabilities in the design of new rotorcraft. The close proximity to ground obstacles, combined with the complexities of piloting, necessitates precise control and robust handling qualities to prevent accidents. However, existing handling quality standards, such as MIL-DTL-32742, reveal limitations in assessing low-level maneuvers. Given the diverse array of new rotorcraft designs, driven by initiatives like the U.S. Army's Future Vertical Lift and NATO's Next Generation Rotorcraft Capabilities, a customized handling qualities evaluation for each design is impractical. In response, a performance-driven strategy has been implemented, scaling Mission Task Elements to align with aircraft performance capabilities. This approach identifies handling quality gaps across the Operational Flight Envelope, concentrating on the aircraft’s effectiveness in achieving task success under varied conditions. Prior simulator studies validate the effectiveness of this method for assessing different configurations. This paper presents flight test results using DLR's ACT/FHS research helicopter, confirming a set of scalable Mission Task Elements developed at DLR's AVES and NASA's VMS simulators. Pilots utilized a Head-Mounted Display for task cueing, eliminating the need for physical infrastructure. The Mission Task Elements proved suitable for evaluating the low-level handling qualities of the ACT/FHS. Although the provided Head-Mounted Display facilitated Handling Qualities evaluations, it encountered some hardware limitations. The scaling for different airspeeds met pilot expectations, and wind compensation functioned as anticipated, enhancing the independence of flight tests from environmental conditions. These findings lead to recommended updates for task descriptions and course cueing requirements, confirming desired performance tolerances.
This paper will present the use of a licensed open-source software application based on commercially available off-the-shelf hardware for the control and data acquisition of aerospace system integration test rigs. System integration test rigs are complex systems requiring real-time deterministic control and high-speed data acquisition. Various aircraft flight systems and subsystems can be tested to see if they interact as they would on the aircraft without an airframe. These systems are critical to ensure interoperability during the development phase and facilitate the interchangeability of actual flight hardware, prototypes, and simulation models throughout the development cycle. Deploying open, flexible, and highly configurable real-time control and data acquisition systems ensures that development milestones will be achieved cost-effectively, whether using actual flight hardware or working with a simulation. This is because, as the prototype hardware is developed, the remaining aircraft systems can still be tested by interacting with the model.
Helicopter aircrew are exposed to high levels of whole-body vibration (WBV) in fight operations, which may degrade their ride comfort and performance in the short-term, and contribute to some health issues in the long-term. This paper presents the latest development and flight test demonstration results of an active seat mount system that is designed to reduce helicopter aircrew WBV levels through active cancellation of the N/rev vibration peaks related to the helicopter main rotor speed. A prototype airworthy hardware of the active seat mount system has been developed based on previous bench-top-test designs to meet airframe integrity requirements for installation and flight testing on the Bell-412 helicopter. Extensive experimental results on human occupants using a shaker table facility and flight demonstrations on the NRC Bell-412 helicopter in representative flight conditions are presented and discussed. The active seat mount system has achieved significant reduction to the occupant WBV levels at the bottom seat cushion interface per ISO2631/MIL-STD-1472G metrics, and also showed effective mitigation to the occupant head vibrations. These investigations demonstrate that the active seat mount technology is a feasible solution for helicopter aircrew WBV mitigation.
Modern aircraft have an established need for a high-performance, open standards solution to interconnect increasing number of digital components including sensors, actuators, controllers, processors, displays and data concentrators. The aircraft can be envisioned as a distributed system requiring highly available, reliable, and deterministic communication network - often termed as digital backbone - for safe operation. This paper introduces a new zonal architecture for aerospace onboard networks using Time-Sensitive Networking (TSN). TSN is an open standard based deterministic Ethernet solution for mission and safety critical networks in aerospace industry that truly meets the Modular Open Standards Approach (MOSA) requirements. This paper also presents a reference implementation of the proposed digital backbone architecture using commercial-off-the-shelf hardware from multiple vendors. Experimental data from laboratory evaluation shows stability, performance, and reliability that meets or exceeds the needs of aerospace use cases. The proposed next generation digital backbone provides significant size, weight, and power savings as well as enables hardware and software modularity using open standards. A specific use case of such a digital backbone is the US Army's Future Vertical Lift (FVL) program, but the proposed architecture is generally applicable to all aircraft networks.
Deos includes an industry standard lightweight TCP/IP stack (LwIP) with a DAL-A sockets library so it can provide data transport during in flight or on ground as part of its standard package. While it may have high data integrity (e.g., through CRC or other such mechanisms), TCP/IP over Ethernet is a non-deterministic protocol. As such, it is not suitable for avionics applications that require determinism or high robustness. In contrast, there are several are several redundant and deterministic data network technologies such as ARINC-664/AFDX, time triggered ethernet (TTE), and time sensitive networking (TSN). These interfaces are based on switched Ethernet technologies and can include system redundancy such that they are applicable for aircraft data network applications. Their feature set enables them to be used as a digital backbone for aircraft control and other applications where both integrity and availability are essential. Each of these solutions generally requires specific end point hardware to implement the protocols in firmware in order to meet the required communication timing and throughput. The implementation of the software device drivers for these technologies on Deos can leverage Deos' I/O Infrastructure (IOI) data distribution service for data decoupling. IOI is a DO-178 DAL-A module that can distribute data based on XML configuration files that specify the data paths, access control and optionally data formatting. It implements an inter-partition communications data interface between avionics applications including ARINC-653 partitions using the ARINC-653 APEX API sampling/queueing ports. Together, these features allow developers to readily adapt to changes in communication structures all through XML configuration files, versus recompiling which would impact the verification evidence of the module. This paper will talk about the different networking standards and how the use of Deos' IOI provides a way for the system to easily adapt to different network configurations without causing the driver library or end application(s) to be modified and thereby minimize change impact for reuse/reverification.
Along with unique and challenging development concerns, target hardware deployment concerns exist for artificial intelligence (AI) and machine learning (ML) applications. Those deployment concerns should be addressed in the planning phase and consist of the issues surrounding the target hardware selection and the certifiability/qualifiable of the target hardware for the AI/ML model deployment. These concerns center around certification issues identified for multi-core processors (MCP), where those MCP issues are amplified for graphics processor units (GPUs) when they are used for general computing. While the use of complex graphics processors for general computing is being reconciled for flight critical applications, the reduction of these concerns is possible through design specific target hardware choices, e.g., selection of Field Programmable Gate Array (FPGA) devices or other certifiable approaches. This paper explores these concerns and proposes design specific target hardware choice strategies to mitigate those concerns.
A new measurement capability was created by combining photogrammetry and metrology techniques to accurately measure one half of the XV-15 Tilt Rotor Research Aircraft at the Smithsonian’s Udvar-Hazy museum. The challenges imposed by the fuselage and surrounding environment at Udvar-Hazy were overcome by careful application of photogrammetry and metrology techniques. Data analyses and processing included the use of multiple reverse engineering programs to accurately generate a complete 3-dimensional water-tight geometry of the aircraft and rotor blade. This paper describes the photogrammetry and metrology measurement systems, technology and hardware set-up, data analysis and processing methods, future work, and lessons learned. In addition, selected measurement results of the fuselage and rotor blade are presented.
A pilot-in-the-loop simulation environment aimed at increasing pilot visual cues without the need of expensive visualization hardware is presented. The proposed solution relies on Virtual Reality (VR) to enhance the pilot immersion in the simulated environment. The project is integrated in the development of the complete simulation framework FRAME-Sim, focused on simulating rotorcraft in early conceptual design stages, and therefore relying on physics-based multibody simulation of the rotorcraft flight dynamics and free/open source software. FRAME-Sim visual environments that are being used include products available to the market as well as homemade solutions developed to obtain the highest level of versatility during the simulation.
This paper describes the development of a suction and oscillatory blowing (SAOB) active flow control (AFC) system, that was aimed towards achieving drag-reduction in a full-scale rotorcraft flight-test environment. The experimental work presented here includes benchtop characterization of the AFC actuators, development and testing of the AFC system using a full-scale two-dimensional airfoil at Tel Aviv University, and full scale testing of a UH-60 External Stores Support System (ESSS) in the CCDC AvMC Aviation Development Directorate 7- by 10-ft wind tunnel up to 140 knots. The airfoil tests composed of two stages, steady suction through holes on the trailing edge and the addition of pulsed blowing using SAOB actuators. The steady suction testing focused on identifying the optimal suction locations, while the SAOB experiments validated the suitability of the chosen actuator arrays to obtain the desired drag reduction at reasonable energetic cost. Tests for both steady suction and SAOB actuators resulted in 15-30 percent drag reduction compared to the clean baseline on the two-dimensional ESSS airfoil. Results from testing the full-scale ESSS identified the complexity of this configuration and the difficulty of transitioning directly from 2D component testing to three-dimensional testing of actual flight hardware. It became evident that by placing SAOB actuators only on the ESSS wing section, only 2-3 percent drag reduction was achievable. Further study is on-going to better understand aerodynamic interactions and develop a path towards more robust drag reduction.
There is emerging demand for multi-ship sensor-based 3D world modeling (3DWM) for autonomy/cognitive decision aiding avionics applications. In these systems, multiple ships collect and transmit perception sensor data that is fused into a common 3DWM, which is then used by other platforms for flight guidance in that environment. This paper illustrates key design considerations for these systems by exploring the fundamental scenario of leader-follower. This paper will detail the design trade space for the leader-follower scenario, focusing on 3DWM database representation/processing and data transmission. To demonstrate the feasibility of a baseline design approach on modern computing hardware, results will be presented from an experimental evaluation of a proof-of-concept system.
ABSTRACT Torque indicating issues continue to plague Power Turbine Modules (PTMs) as a top reason for return. These issues can be linked to failed torque and overspeed sensors and PTM torque reference shaft issues including; sticking shafts due to torque stiction and sheared pins connecting PTM drive shafts to torque reference shafts. At the end of the PTM shaft is the pinning hardware for the torque reference shaft. In shipping and during handling of the PTM damage can occur causing the pin to shear and fail. They can fail due to inadvertent contact with the PTM or torque shaft, during shipping and handling, or after prolonged usage. Defining a reliable inspection procedure to make the determination that the PTM shaft is faulty prior to ‘on wing’ installation can save time and money for the operator. In addition, the repair procedure for sheared pin is to replace pinning hardware at Corpus Christi Army Depot (CCAD) machine shop. During the repining of the hardware the holes must be located a minimum distance from each other to preserve the integrity of PT shaft and aft insert parent metal according to the Depot Maintenance Work Requirement manual. In the presence of machine shop error, failing to maintain the minimum distance between pin holes prevents viable PT shafts from use in production. Identifying a process improvement for repair procedures of pin hardware at the machine shop can save time and money invested in overhauled PT shafts for the depot.
Automotive engineering has been a game of delivering more value with minimal resources confronting conflicting design choices at every design step. As more and more electronics enters the game, it becomes imperative to critically evaluate various design choices to deliver a robust hardware backbone which guarantees a robust performance on an ever-reducing budget. Hardware interface with the outside environment in particular needs to be equipped with a significant robustness. Harsh transients, tough environmental conditions, further complicate the rules to the game.
NASA is preparing for the next generation of CubeSats that are propelled and will make directional maneuvers. The new gimbal mount provides a seat for the motor, and controls the position of the thrusters that propel the CubeSat as it moves about and/or changes orbits.
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