Proceedings of the Vertical Flight Society 78th Annual Forum最新文献

{"title":"Evaluation of Simulator Cueing Fidelity for Rotorcraft Certification by Simulation","authors":"P. Podzus, Jur Crijnen, Michael Jones, Stefan van'tHoff, Paul Breed","doi":"10.4050/f-0078-2022-17572","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17572","url":null,"abstract":"\u0000 Before their entry into service, newly developed rotorcraft must go through an extensive certification process in order to receive a type certificate from the certification authority. A vital and long-lasting phase of this process is the compliance demonstration. This phase involves a large amount of flight testing, which leads to high expenses for the rotorcraft manufacturer and can be considered as high-risk when it comes to rotorcraft safety, especially for scenarios including control system or engine failures, as in the case of a category-A rejected take-off (CAT-A RTO). The Rotorcraft Certification by Simulation (RoCS) CleanSky2 research project aims to reduce the amount of flight testing required for compliance demonstration by using flight simulation, to achieve an increase in safety (less hazardous situations) and effectiveness, and a reduction in certification duration and costs. Within the project, pilot-in-the-loop simulator test campaigns were conducted at DLR and NLR, investigating the visual cueing fidelity required for performing a CAT-A RTO scenario. Emphasis was put on varying the available field of view (FoV) for the pilot and investigating the suitability of virtual reality (VR) devices. Subjective and objective results from these simulator campaigns, as well as pilot comments are presented in this paper.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130129100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mission System Needs for Small Unmanned Systems","authors":"Max G. Taylor, Matthew Cunnien, James Kleveland","doi":"10.4050/f-0078-2022-17495","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17495","url":null,"abstract":"\u0000 The United States (US) Department of Defense (DoD) is looking to reverse the trend of new programs costing significantly more than their predecessors while providing advanced capabilities to the warfighter by supplementing existing manned platforms with small Unmanned Air Systems (sUAS). Traditionally sUAS were leveraged for limited tactical objectives with two-way communication to a single entity such as a ground station or as part of a single manned-unmanned team (MUM-T). However, advancements in collaborative networks, mature autonomy and continued miniaturization of key technologies have expanded the potential for a broader operational use of sUAS. The multi-domain connected battlespace of the future envisions significant strategic roles for sUAS to provide actionable information more broadly to the joint forces.\u0000The expanded use of sUAS platforms is evident in the future US Army strategy to augment the existing and future capabilities of its own vertical lift platforms. In order to dis-integrate and exploit enemy threat systems the US Army intends to leverage sUAS systems such as Air Launched Effects (ALE) and Future Tactical Unmanned Aircraft Systems (FTUAS) (Ref. 1). These will be part of the Future Attack Reconnaissance Aircraft (FARA) ecosystem allowing extended reconnaissance, security, and attack operations. The US Air Force is also identifying new Concepts of Operation (CONOPS) which can leverage sUAS as a force multiplier to help against emerging threats (Ref. 2). This includes existing continued enhancement of intelligence, surveillance, and reconnaissance (ISR) capabilities as well as new MUM-T and swarming CONOPS. \u0000In this new role, there are several challenges that emerge for sUAS mission systems. \u0000- Existing sUAS security boundaries are focused on vulnerabilities between the aircraft and the ground station or controlling vehicle. Introduction of sUAS in the connected multi-domain battlespace opens the security boundary to include all participants consuming data from these vehicles. This results in additional attack vectors for adversaries requiring new security considerations for a sUAS. \u0000- Secure and available communications are key to supporting multi-domain battlespace doctrine at the timing and tempo required to gain advantage on the adversary. Introduction of sUAS to this assumes the ability to interconnect securely with existing and future communication protocols at a significantly reduced size, weight and power. Availability of secure communication from sUAS is challenging when considering using these unmanned systems to support operations in contested environments. \u0000- Autonomous operations and processing on the edge are key to reaping the benefits of the sUAS operating in a MUM-T environment. Moving the processing of key capabilities to the edge allows for the quicker response times and the ability for the sUAS to continue operations in contested environments and report back when secure communications become available.","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"173 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131638854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"eVTOL Component Testing for Supporting Algorithmic Icing Detection","authors":"Robert McKillip(Jr.)","doi":"10.4050/f-0078-2022-17632","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17632","url":null,"abstract":"\u0000 Component testing in support of the development of a model-based algorithmic Icing Detection Filter (IDF) for use on eVTOL aircraft is described. The IDF represents an extension of prior work on holistic aircraft icing detection where data from individual electric motor controllers is monitored to track performance degradation effects due to accreted icing on rotating components. Icing accretion tests were conducted at a variety of conditions on representative components from a Lift+Cruise eVTOL configuration in both an icing hover chamber and an icing wind tunnel. Several different simulation tools were used to assess their capability to predict observed trends from the test data, and while icing accretion on rotating components was modeled sufficiently, non-rotating components appeared to accumulate ice more uniformly than suggested from the droplet trajectory analysis used.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"42 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133647081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Damper Model Identification Using Hybrid Physical and Machine Learning Based Approach","authors":"M. Zilletti, Ermanno Fosco","doi":"10.4050/f-0078-2022-17523","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17523","url":null,"abstract":"\u0000 In this paper the identification of a time domain model of a helicopter main rotor lead-lag damper is discussed. Previous studies have shown that lead-lag dampers have a significant contribution to the overall aircraft dynamics, therefore an accurate damper model is essential to predict complex phenomena such as, instabilities, limit cycles, etc. Due to the inherently nonlinear dynamics and the complex internal architecture of these components, the model identification can be a challenging task. In this paper, a hybrid physical/machine learning based approach, has been used to identify a damper model based on experimental test data. The model, called grey box, consists of a combination of a white box, i.e. a physical model described by differential equations and a black box, i.e. regression numerical model. The white box approximates the core physical behaviour of the damper while the black box improves the overall accuracy by capturing the complex dynamic not included in the white box. The paper shows that, at room temperature, the grey box is able to predict the damper force when either a multi-frequency harmonic or a random input displacement is imposed. The model is validated up to 20 Hz and for the entire damper dynamic stroke. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117156516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transition Performance Of Tilt Propeller Aircraft","authors":"Alex M. Stoll, Gregor Milkic","doi":"10.4050/f-0078-2022-17443","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17443","url":null,"abstract":"\u0000 A simple model of the transition aerodynamics of Joby Aviation's electric tilt-propeller VTOL aircraft was developed by combining a surrogate model of CFD propeller solutions with semi-empirical models of airframe aerodynamics and interactional aerodynamics. The model was calibrated to match CFD results of the entire aircraft, as well as f light test results of the actual aircraft. Using this model, loads and power requirements across the range of shaft tilt angle and airspeed combinations for trimmed flight -- the \"conversion corridor\" often described in tiltrotor performance reports -- are analyzed, and resulting performance limitations are discussed. Additionally, a novel approach to transition flight is introduced in which the angle of attack and shaft angle are automatically determined by the flight controller, rather than manually controlled. Using the simple transition aerodynamics model, transition loads and power requirements with this control approach are discussed, and transition flight using this control approach is shown to allow for high performance given reasonable limitations.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121981443","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparing Strategies for DNS Based Optimization of Airfoils for Martian Rotorcraft","authors":"Lidia Caros, Julian Blank, O. Buxton, P. Vincent","doi":"10.4050/f-0078-2022-17475","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17475","url":null,"abstract":"\u0000 Martian atmospheric conditions present various challenges when designing rotorcraft. Specifically, the thin atmosphere and lower speed of sound compared to Earth requires Martian rotor blades to operate in a low-Reynoldsnumber ( approximately equal to 103 to 104) compressible regime, for which conventional airfoils have not been designed. Airfoils with sharp leading edges and flat surfaces have been shown to perform better than conventional airfoils under these conditions. In order to find the optimal airfoils, several studies have explored optimizing non-conventional airfoils with evolutionary techniques. These algorithms usually require many cost function evaluations, and hence, they typically employ Reynolds-Averaged Navier Stokes (RANS) solvers because of their low computational cost. However, RANS solvers have limited predictive capability when the flow becomes unsteady and separated at moderate angles of attack. Enabled by recent advances in solver technology and GPU hardware, we are able to overcome this limitation by undertaking optimization using high-fidelity Direct Numerical Simulations (DNS), able to capture the flow physics, via the compressible flow solver in PyFR (www.pyfr.org). In order to reduce the cost of the optimization, given that it involves expensive cost function evaluations, the current study compares two multi-objective optimization strategies using pymoo (www.pymoo.org) as the optimizer. Specifically, the study compares the cost of Genetic Algorithm (GA) optimization with two-dimensional DNS used to evaluate the cost function, with the cost of surrogate-assisted GA optimization where the model is generated and updated with two-dimensional DNS. Results help elucidate efficient strategies for high-fidelity two- and three-dimensional DNS optimization for aerospace applications, specifically rotorcraft airfoils in Martian atmospheric conditions.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115229199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Bambi Bucket: Evolution of the Most Versatile Aerial Firefighting Tool","authors":"Robert Roedts(II)","doi":"10.4050/f-0078-2022-17589","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17589","url":null,"abstract":"\u0000 From humble beginnings in the 1940s, helicopters have become an integral part of managing and fighting wildfires throughout the world. Starting in the 1950s and over the next several decades, various government agencies increased the utilization of helicopters in their management of wildfires across the US and deployed new technologies. One of the most impactful technologies developed was using a slung bucket to dump water. Initially using repurposed construction and agricultural equipment, these early generation buckets were dipped in sources of water and released using a simple mechanical gate system. In parallel with these early generation buckets, the technique of long-line operations were being perfected that allowed flight crews to increase separation from terrain and increased control of the external load. Over the next several decades, these buckets were steadily improved and incorporated into firefighting operations across the work. In addition, the use of long lines for external loads allowed the use of remote water sources and increased precision water drops. In 1982, Don Arney developed the ubiquitous \"Bambi Bucket.\" This bucket was innovative in many ways: easily scalable, lightweight, collapsible, stowable, and reduced drag. Today, helicopters have become the main aerial resource to fight wildfires across the world. Furthermore, helicopters outfitted with Bambi Buckets account for 90% of all firefighting operations. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115296073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transition Trajectory Planning and Control for Quadrotor Biplanes in Obstacle Cluttered Environments","authors":"Kristoff McIntosh, Jean-Paul F. Reddinger, Jae Kim, Sandipan Mishra","doi":"10.4050/f-0078-2022-17639","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17639","url":null,"abstract":"\u0000 This paper presents a trajectory planner and a control architecture capable of guiding a quadrotor biplane tailsitter (QRBP) through obstacle cluttered environments. The trajectory planner is formulated as an optimization problem that uses a differentially flat, point-mass model of a QRBP that considers wake effects on the aerodynamic forces generated during transition. Obstacle avoidance is realized as a state constraint in the optimization problem that defines 'no-flight zones' or regions where the QRBP cannot enter based on obstacle size and safety clearance requirements. The 6DOFcontrol architecture is designed as a set of cascaded dynamic inversion controllers that use the aerodynamic feedforward signals produced by the trajectory planner to complete the inversion in the outer loop. To show the effectiveness of the obstacle avoidance path planning methodology, time-optimal trajectories are generated for two f light missions (the hover to forward flight and vice versa) through cluttered environments. The control architecture is validated on these two cases using a high fidelity flight dynamics simulation of a QRBP. The computational efficiency of the trajectory planner and the tracking performance of the control architecture are then empirically validated.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114907814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design, Development, and Flight Testing of a 25-Kilogram Quad Cyclocopter","authors":"Ramsay Ramsey, Atanu Halder, Saul Sanchez, David A. Coleman, Moble Benedict","doi":"10.4050/f-0078-2022-17487","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17487","url":null,"abstract":"\u0000 This paper describes the design, development, and tethered flight testing of a quad-cyclocopter weighing 25 kilograms and 1.8 m x 1.4 m x 0.8 m in dimension. This cyclocopter features four cantilevered cyclorotors with a unique f ive-bar blade pitching mechanism. The cyclorotor design is chosen through systematic parametric studies using an in-house 2-D computational fluid dynamics (CFD) solver. Based on the parametric studies, the final design selected is a 6-bladed cyclorotor with 0.67 chord-to-radius ratio, symmetric NACA 0015 airfoil, and pitch amplitude of 45? because it provided high thrust and power loading (thrust/power) at a low operating rotational speed of 700 RPM. The cyclorotor blades are manufactured with a foam core and carbon fiber skin resulting in lightweight blades with large bending and torsional stiffness. The rotor supporting structure and transmission is designed to be lightweight and resilient to large centrifugal loads and dynamic torques, respectively. A minimum mass airframe is designed and constructed from carbon fiber tubes to handle the vibratory loads from cyclorotors, mount electronics and batteries, and provide attachment points for the carbon fiber cowling. The attitude control strategy utilizes a combination of RPM control and thrust vectoring of the four cyclorotors (eight independent control parameters), resulting in an over actuated system. A custom autopilot uses a closed-loop cascaded proportional-integral-derivative (PID) controller to stabilize the aircraft in hovering flight. The vehicle has been flight tested while tethered and achieved lift off.\u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123640002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Digital Transformation of a 6000-Year-Old Process","authors":"H. Woodworth","doi":"10.4050/f-0078-2022-17564","DOIUrl":"https://doi.org/10.4050/f-0078-2022-17564","url":null,"abstract":"\u0000 Integration of advanced technologies in the casting commodity through digital transformation efforts is essential to future success of rotorcraft transmission castings. This paper reviews the advanced technologies that have been integrated into the casting process for transmission housings. The transformation in casting designs, solidification modeling, mold fabrication, casting techniques, thermal and mechanical post processing, inspection, and quality management are all impacted by new technologies and driven by the continued digital thread in the manufacturing process. The casting manufacturing process is 6000 years old, but the complexity of aircraft requirements and part designs has outpaced capability of standardized casting processes. Digital transformation driven technologies create repeatable processes that reduce production scrap and development lead times. \u0000","PeriodicalId":223727,"journal":{"name":"Proceedings of the Vertical Flight Society 78th Annual Forum","volume":"7 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125175864","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}