Moble Benedict

University of Maryland, College Park | UMD, UMCP, University of Maryland College Park · Department of Aerospace Engineering

In this paper the flight dynamics of a 33-gram twin-cyclocopter is analyzed via deriving a Linear Time Invariant (LTI) dynamics model from flight test data. The twin-cyclocopter is a novel micro air vehicle that uses two co-rotating cycloidal rotors to generate thrust and a coaxial nose rotor to counteract the reaction torque and provide additional...

This paper describes the development and flight testing of a personal air vehicle by team Harmony for the GoFly Prize competition. The competition emphasized an open‐air flight experience, and the final aircraft was scored by size (≤8.5 ft), noise (<87 dBA), and speed (>30 kt). The highest scoring team would win a $1 million grand prize. Team Harmo...

This paper discusses the development of a micro air vehicle scale quad-cyclocopter for the purpose of investigating cyclorotor application to low Reynolds number ([Formula: see text]) flight. The 70-gram vehicle is the lightest quad-cyclocopter developed to date by an order of magnitude and only the second to achieve forward flight. It utilized two...

The paper presents the development of a multi-disciplinary modeling framework to predict the system-level performance of a diverse range of electric vertical takeoff and landing (eVTOL) aircraft. A key feature of this framework is its modular architecture where the various components are modeled separately and then integrated together based on the...

Small electric drones are popular vehicles for consumers and researchers. However, literature contains little data on in-flight aerodynamic loads that could validate aerodynamic or electric powertrain design tools. We developed a specially instrumented quadcopter to directly measure and record rotor torque and rotational speed during flight. We use...

This paper describes the development and flight testing of the first-ever air-launched tail-sitter UAV platform. Integrated with VTOL capability, the platform can be launched from various platforms, perform long-endurance loiter tasks and low-speed or hover flight, and land vertically in limited spaces. This work covers the experimental exploration...

This paper investigates the upward scalability of a cycloidal rotor (also known as a cyclorotor) from an aeromechanics standpoint while utilizing a two-dimensional computational fluid dynamics (CFD) solver and a lower order aeroelastic model. The CFD results show that the nondimensional thrust remains almost unchanged with increasing Reynolds numbe...

This paper addresses the problem of developing an algorithm for autonomous ship landing of vertical take-off and landing (VTOL) capable unmanned aerial vehicles (UAVs), using only a monocular camera in the UAV for tracking and localization. Ship landing is a challenging task due to the small landing space, six degrees of freedom ship deck motion, l...

This paper describes the development and flight testing of a compact, re-configurable, hover-capable rotary-wing micro air vehicle that could be tube launched for increasing mission range. The vehicle design features a coaxial rotor with foldable blades, thrust-vectoring mechanism for pitch/roll control and differential rpm for yaw control. The veh...

Mission-adaptive aerostructural design considers the alteration of structural geometries to improve multi-objective performance across multiple aerodynamic environments associated with flight conditions derived from specific mission profiles. To accomplish this, adaptive structures design requires evaluating the aerostructural responses for each po...

The paper discusses an experimental effort aimed at quantifying and comparing the relative flight dynamics and gust response of a two-winged, biomimetic, hover-capable robotic hummingbird (RH) with wing kinematic modulation methods for flight control, against those of a quadrotor (QR) with the same mass, inertias, and motor and battery mass fractio...

This paper discusses the development of a micro-scale quad-cyclocopter for the purpose of investigating cyclorotor application to low Reynolds number flight. The 70-gram vehicle was the lightest quad-cyclocopter developed to date by an order of magnitude and only the second to achieve forward flight. It utilized two counter-rotating pairs of cyclor...

The paper discusses an experimental parametric study to maximize the hover efficiency of a coaxial rotor system for a micro air vehicle (MAV) that could potentially be launched from a 40 mm grenade launcher to achieve improved mission range and endurance. Prior to testing the rotors in the coaxial configuration, isolated rotor tests were performed...

The paper investigates the unsteady forces and flowfield of a cycloidal rotor blade undergoing forward flight motion through water tunnel experiments. A particle image velocimetry (PIV) system is used in conjunction with an instrumented blade to measure both the two-dimensional flow velocity around the blade and the fluid dynamic forces. The flow-f...

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-hous...

The brushless DC motors of small unmanned aerial systems typically rely on axial air-cooling. Modeling the motor's thermal dynamics requires knowledge of the convective heat transfer coefficient. However, the coefficient is an extrinsic property which depends on surrounding conditions. As such, motor manufacturers provide no relevant data which sty...

Aeromechanics of highly flexible flapping wings is a complex nonlinear fluid–structure interaction problem and, therefore, cannot be analyzed using conventional linear aeroelasticity methods. This paper presents a standalone coupled aeroelastic framework for highly flexible flapping wings in hover for micro air vehicle (MAV) applications. The MAV-s...

This paper introduces a control scheme to vector thrust in marine cycloidal propellers with non-zero forward speed, despite the presence of measurement noise and current-like disturbances. Cycloidal propellers utilize 360° thrust-vectoring to provide agile maneuvering to surface vessels like tugboats and double ended ferries, but have yet to be uti...

The paper discusses an intelligent vision-based control solution for autonomous tracking and landing of Vertical Take-Off and Landing (VTOL) capable Unmanned Aerial Vehicles (UAVs) on ships without utilizing GPS signal. The central idea involves automating the Navy helicopter ship landing procedure where the pilot utilizes the ship as the visual re...

The paper discusses an intelligent vision-based control solution for autonomous tracking and landing of vertical take-off and landing (VTOL) capable unmanned aerial vehicles (UAVs) on ships without utilizing GPS signals. The central idea involves automating the Navy helicopter ship landing procedure where the pilot utilizes the ship as the visual r...

View Video Presentation: https://doi.org/10.2514/6.2021-3218.vid The paper discusses a deep reinforcement learning (RL) control strategy for fully autonomous vision-based approach and landing of vertical take-off and landing (VTOL) capable unmanned aerial vehicles (UAVs) on ships in the presence of disturbances such as wind gusts. The automation cl...

The paper discusses a machine learning vision and nonlinear control approach for autonomous ship landing of vertical flight aircraft without utilizing GPS signal. The central idea involves automating the Navy helicopter ship landing procedure where the pilot utilizes the ship as the visual reference for long-range tracking, but refers to a standard...

This paper investigates the unsteady force production on a UAV scale cycloidal rotor blade undergoing forward flight motion via experiments in a water tunnel as well as an unsteady aerodynamic model and a computational fluid dynamics (CFD) model. While time-averaged forces can shed light on cycloidal rotor performance, it is important to be able to...

In this paper a linear flight dynamics model of a micro twin cyclocopter is experimentally derived from flight test data and analyzed. The twin cyclocopter is a novel aerial vehicle that uses two cyclorotors spinning in the same direction to generate thrust, and a nose propeller to counter the reaction torque as well as provid additional thrust. Th...

This paper discusses the flight testing and system identification of a compact, re-configurable, rotary-wing micro air vehicle concept capable of sustained hover and could potentially be launched from a 40mm grenade launcher. By launching these energy-constrained platforms to a target area, the mission range could be significantly improved. The veh...

This paper describes the development and flight testing of a personal air vehicle by team Harmony for the Boeing GoFly X-prize challenge. For the $1mil grand prize, aircraft were scored by compact size, speed, low noise, and endurance. The team chose a coaxial electric helicopter configuration to maximize rotor area and reduce disk loading for effi...

This paper describes the development and flight testing of a compact, re-configurable, rotary-wing micro air (MAV) vehicle capable of sustained hover and could potentially be launched from a 40mm grenade launcher. Launching the vehicle as a projectile over the target area could significantly improve the mission range for these energy-constrained pl...

The paper discusses a novel vision-based estimation and control approach to enable fully autonomous tracking and landing of vertical take-off and landing (VTOL) capable unmanned aerial vehicles (UAVs) on moving platforms without relying on a GPS signal. A unique feature of the present method is that it accomplishes this task without tracking the la...

This paper describes the development of a semi-empirical sizing algorithm for the outrunner brushless DC (BLDC) motors used in electric unmanned aerial systems (UAS) with a maximum gross takeoff weight of 25 kg (55 lb.). Given an operating torque and a desired geometric aspect ratio (stator diameter/length), the algorithm can predict the mass, geom...

This paper investigates a novel concept of using cycloidal propellers to augment the maneuverability of unmanned underwater vehicles. Cycloidal propellers are cross-flow propellers that utilize 360∘ thrust vectoring to provide agile maneuvering to surface vessels like yachts, tug boats, buoy tenders and double ended ferries, but have yet to be util...

The paper discusses the development of a nonlinear aeroelastic coupled trim model of a twin cyclocopter in forward flight. The twin cyclocopter consists of two cycloidal rotors as main thrusters and a conventional nose rotor for pitch-torque balance. It is shown that five control inputs [mean and differential revolutions per minute (RPM), mean and...

This paper describes the development of a compact and re-configurable rotary-wing micro air vehicle (MAV) that is capable of sustained hover and could potentially be launched from a 40 mm grenade launcher in the future. Launching the vehicle as a projectile up to the point of operation could significantly improve the mission range for these energy-...

This paper provides a fundamental understanding of the unsteady fluid-dynamic phenomena on a cycloidal rotor blade operating at ultra-low Reynolds numbers (Re ∼ 18,000) by utilizing a combination of instantaneous blade force and flowfield measurements. The dynamic blade force coefficients were almost double the static ones, indicating the role of d...

This paper provides a fundamental understanding of the unsteady aerodynamic phenomena on a cycloidal rotor blade operating with symmetric as well as asymmetric pitching at ultralow Reynolds numbers (Re≈18,000) by using a combination of experimental (force and flowfield measurements) and computational fluid dynamics (CFD) studies. The instantaneous...

This paper details the performance and flowfield measurements on a mesoscale cycloidal rotor (rotor radius of 1 in.), which operates at ultralow Reynolds numbers (Re∼11,000) and uses a design different from previous cycloidal rotor studies. The mesoscale rotor uses a cantilevered blade with a flat-plate airfoil and low-aspect-ratio elliptical blade...

In this paper, the aeromechanics of a cycloidal rotor (or cyclorotor) is investigated to understand the effect of blade flexibility on the performance of the rotor in hover. Toward this, experiments are conducted on cyclorotors using moderately and highly flexible blades. These studies show that, with increasing blade flexibility, the rotor thrust...

This paper describes the design, controls system development, and hover testing of a 60 -g meso-scale cycloidal-rotor based (cyclocopter) micro air vehicle. The cycloidal rotor (cyclorotor) is a revolutionary vertical take-off and landing concept with a horizontal axis of rotation. The twin-cyclocopter utilizes two optimized cyclorotors and a horiz...

We describe the development of control strategies and wind tunnel experiments that enabled the first successful stable forward flight of a cyclocopter purely using thrust vectoring. Unlike a conventional helicopter, a cyclocopter is propelled in forward flight without pitching the entire vehicle and instead maintains a level attitude by vectoring t...

This paper describes the experimental design studies conducted to maximize the hover endurance of a micro air vehicle-scale quadrotor helicopter (gross weight < 50 g) by careful design and selection of the individual subsystems while understanding their interdependencies. The different subsystems of the quadrotor that were examined include the roto...

The present study is in response to increased interest towards assessing the feasibility of a small-scale autonomous helicopter (gross weight less than 1 kg) for Martian exploration. An autonomous rotorcraft may be ideally suited for such an application because of its unique advantages, which include the ability to take off/land vertically on harsh...

The paper focuses on understanding the mechanism of force production on a hover-capable flapping-wing system by using a combination of direct force measurements and flowfield studies. The experiments were conducted in air at a Reynolds number of approximately 25,000 (based on mean chord and maximum tip speed), which is the typical operating regime...

This paper describes the systematic experimental and computational studies performed to investigate the performance of a small-scale vertical-axis wind turbine using dynamic blade pitching. A vertical-axis wind turbine prototype with a simplified blade pitch mechanism was designed, built, and tested in the wind tunnel to understand the role of pitc...

This paper describes a fundamental experimental study, which involved systematic performance and flowfield measurements (PIV) to understand and optimize the hover performance of a MAV-scale helicopter rotor operating at Reynolds numbers lower than 30,000. The rotor parameters that were varied include blade airfoil profile, blade chord, number of bl...

Experiments were systematically executed with a coupled computational fluid/structural dynamics aeroelastic analysis for a micro air vehicle scale flexible flapping-wing undergoing pure flap wing kinematics in forward flight. Two-dimensional time-resolved particle image velocimetry and force measurements were performed in a wind tunnel where V ∞ =...

This paper details the design, development and flight testing of a 62-gram hummingbird-inspired flapping wing micro air vehicle with hovering capability. The key barriers in the development of this vehicle included optimizing the wing design at high flap frequencies by utilizing aeroelastic tailoring to produce the required lift for hover, designin...

This paper describes the system identification methodology and the identified flight dynamics model of a cyclo-copter micro air vehicle (MAV) in forward flight. The cyclocoper utilizes two cycloidal rotors (cyclorotors), a novel horizontal-axis propulsion system with rotating wings. The forward flight control strategy employs independent rpm contro...

This paper describes the experimental design studies conducted to maximize the hover endurance of a MAV-scale quadrotor helicopter by careful design/choice of the individual subsystems while understanding their interdependencies. The different subsystems of the quadrotor that were examined include the rotors, motors, electronic speed controllers, g...

Targeted experiments in parallel with a systematic computational-fluid-dynamics analysis were performed for a micro-air-vehicle-scale rigid flapping wing in forward flight. Two-component time-resolved particle-image-velocimetry measurements were performed in an open-circuit wind tunnel on a wing undergoing pure flap-wing kinematics at a fixed wing-...

This paper examines the flow physics and principles of force production on a cycloidal rotor (cyclorotor) in forward flight. The cyclorotor considered here consists of two blades rotating about a horizontal axis, with cyclic pitch angle variation about the blade quarter-chord. The flow field at the rotor mid-span is analyzed using smoke flow visual...

This paper describes the systematic experimental and computational studies performed to obtain a fundamental understanding of the physics behind the lift and thrust production of a cycloidal rotor (cyclorotor) in forward flight fora unique blade pitching kinematics. The flow curvature effect (virtual camber and incidence due to the curvilinear flow...

This paper describes the control strategies, avionics system development, and wind tunnel testing that enabled the first successful stable forward flight of a cycloidal-rotor aircraft (cyclocopter) purely using thrust vectoring. The present 550-gram vehicle has a hybrid configuration utilizing two optimized cycloidal rotors and a conventional prope...

This paper discusses the control methodology, flight dynamics identification, and disturbance rejection analysis in hover of a revolutionary horizontal-axis rotary-wing concept: the twin cyclocopter. The vehicle has a gross weight of 500g (1.25 by 1.67 by 1ft in dimensions) and comprises two highly optimized cyclorotors along with a tail rotor for...

Systematic wind tunnel measurements were conducted on a small-scale cycloidal rotor (cyclorotor) with a span and diameter of approximately 15 cm. The three parameters varied in the studies were the blade pitch amplitude, phasing of blade pitch with respect to the freestream direction, and advance ratio. The measured quantities included the rotor li...

A study was conducted to demonstrate the development of a micro twin-rotor cyclocopter capable of autonomous hover. The blades used on the twin-cyclocopter were fabricated mostly out of foam with carbon-fiber reinforcement inside and a single-layer 0/90 degree carbon composite prepreg skin wrapped around the foam core at the blade tips. Foam helped...

This paper describes the systematic performance measurements conducted to understand the role of rotor geometry and blade pitching kinematics on the performance of a microscale cycloidal rotor. Key geometric parameters that were investigated include rotor radius, blade span, chord, and blade planform. Because of the flow curvature effects, the cycl...

A cycloidal rotor is an innovative horizontal axis propulsion system, which is utilized in the present study to develop a fully-controllable flying aircraft (known as "Cyclogyro"). The present 535 gram cyclogyro uses a hybrid configuration with two cyclorotors and a horizontal tail rotor. Since a cycloidal rotor relies on cyclic blade pitching for...

This paper examines the flow physics and principles of force production on a two-bladed cycloidal rotor (or cyclorotor) in forward flight. The flow field is analyzed using experimental flow visualization techniques and particle image velocimetry (PIV) measurements. Both time-averaged and phase-averaged flow fields are examined at different freestre...

This paper describes the systematic experimental and computational (CFD) studies performed to investigate the performance of a small-scale vertical axis wind turbine (VAWT) utilizing dynamic blade pitching. A VAWT prototype with a simplified blade pitch mechanism was designed, built and tested in the wind tunnel to understand the role of pitch kine...

The paper focuses on understanding the mechanism of force production on a hover capable flapping wing system by utilizing a combination of direct force measurements and flowfield studies. The experi- ments were conducted in air at a Reynolds number of approximately 25,000, which is the typical operating regime of small flapping wing micro air vehic...

This paper describes a series of experimental studies performed to investigate the role of asymmetric pitching kinematics on cycloidal rotor performance in forward flight. Asymmetric pitching kinematics for the cyclorotor is achieved by introducing a non-zero mean pitch angle, which allows the blades to operate at a higher pitch amplitude in one ha...

A novel dual-differential four-bar flapping mechanism that can accurately emulate insect wing kinematics in all three degrees of freedom (translation, rotation and stroke plane deviation) is developed. The mechanism is specifically designed to be simple and scalable such that it can be utilized on an insect-based flapping wing micro air vehicle. Ki...

This paper discusses the systematic experimental and vehicle design/development studies conducted at the University of Maryland which culminated in the development of the first flying Cyclocopter in the history. Cyclocopter is a novel Vertical Take-Off and Landing (VTOL) aircraft, which utilizes cycloidalrotors (cyclorotors), a revolutionary horizo...

Experimental studies were conducted by flapping a rigid rectangular wing with a mechanism that was capable of emulating complex insect wing kinematics including figure of eight motion, in order to explore the fundamental unsteady flow on a flapping wing at MAV scale Reynolds numbers. Force and moment measurements were obtained from a miniature six-...

This paper describes the systematic experimental and computational (2-D CFD) studies performed to obtain a fundamental understanding of the physics behind the lift and thrust production of a cycloidal rotor (cyclorotor) in forward flight for a unique blade pitching kinematics. The flow curvature effect (virtual camber and incidence due to the curvi...

This paper describes the aeroelastic model to predict the blade loads and the average thrust of a micro-air-vehicle-scale cycloidal rotor. The analysis was performed using two approaches: one using a second-order nonlinear beam finite element method analysis for moderately flexible blades and a second using a multibody-based large-deformation analy...

This paper describes the systematic experimental studies performed to optimize the performance of a microscale cycloidal rotor. Parametric studies were conducted to determine the dependence of cycloidal rotor performance on rotational speed, blade pitching amplitude (symmetric and asymmetric pitching), blade airfoil profile, number of blades (at co...

A four-bar based flapping mechanism was designed and built to emulate insect wing kinematics employing passive wing pitching. Detailed experimental parametric studies were performed using various wing structural designs to optimize the passive pitching kinematics to increase steady lift. The maximum lift produced by a single wing was around 55 gram...

Systematic experimental studies were performed to understand the role of two key degrees of freedom, flapping and pitching, in aerodynamic performance of a flapping wing, in both hover and forward flight. Required flapping kinematics is prescribed mechanically, and dynamic pitching/twisting is obtained passively using inertial and aerodynamic force...

Performance and flowfield measurements were conducted on a small-scale cyclorotor for application to a micro air vehicle. Detailed parametric studies were conducted to determine the effects of the number of blades, rotational speed, and blade pitching amplitude. The results showed that power loading and rotor efficiency increased when using more bl...

This paper describes the aeroelastic model to predict the blade loads and the average thrust of a micro air vehicle (MAV) scale cycloidal rotor. The analysis was performed using two approaches, one using a non-linear FEM analysis for moderately flexible blades and second using a multibody based large-deformation analysis (especially applicable for...

The viability of a cyclorotor for powering a hover-capable micro air vehicle (MAV) was examined by making performance and flow field measurements. Parametric studies were conducted to determine the dependence of performance on rotational speed, the amplitude of the blade pitch, the blade airfoil shape, and blade flexibility. All of the experiments...

A dierential-four-bar based apping mechanism was designed and built to emulate insect wing kinematics with an active pitching ability for a hovering apping-wing micro air vehicle (MAV). The apping mechanism was designed to have symmetric maximum upstroke and downstroke motions. Numerous wings with the same planform area were built and tested using...