scholarly journals Design, Modeling, and Simulation of a Wing Sail Land Yacht

2021 ◽  
Vol 11 (6) ◽  
pp. 2760
Author(s):  
Vítor Tinoco ◽  
Benedita Malheiro ◽  
Manuel F. Silva
Keyword(s):  
Modeling And Simulation ◽  
3D Model ◽  
Angular Position ◽  
Simulation Method ◽  
Polar Diagram ◽  
Control Techniques ◽  
Drag Forces ◽  
Lift And Drag ◽  
Rotating Wing ◽  
Novel Design

Autonomous land yachts can play a major role in the context of environmental monitoring, namely, in open, flat, windy regions, such as iced planes or sandy shorelines. This work addresses the design, modeling, and simulation of a land yacht probe equipped with a rigid free-rotating wing sail and tail flap. The wing was designed with a symmetrical airfoil and dimensions to provide the necessary thrust to displace the vehicle. Specifically, it proposes a novel design and simulation method for free rotating wing sail autonomous land yachts. The simulation relies on the Gazebo simulator together with the Robotic Operating System (ROS) middleware. It uses a modified Gazebo aerodynamics plugin to generate the lift and drag forces and the yawing moment, two newly created plugins, one to act as a wind sensor and the other to set the wing flap angular position, and the 3D model of the land yacht created with Fusion 360. The wing sail aligns automatically to the wind direction and can be set to any given angle of attack, stabilizing after a few seconds. Finally, the obtained polar diagram characterizes the expected sailing performance of the land yacht. The described method can be adopted to evaluate different wing sail configurations, as well as control techniques, for autonomous land yachts.

scholarly journals Overcoming Stopovers in Cycloidal Rotor Propulsion Integration on Air Vehicles

2012 ◽  
Author(s):  
José C. Páscoa ◽  
Galina I. Ilieva
Keyword(s):  
Large Scale ◽  
Reynolds Numbers ◽  
Rotational Axis ◽  
Major Drawback ◽  
Drag Forces ◽  
Flow Mechanisms ◽  
Weight Penalty ◽  
Thrust Vector ◽  
Lift And Drag ◽  
Rotating Wing

A cyclorotor (also known as a cyclocopter or cyclogiro) is a rotating-wing system where the span of the blades runs parallel to the axis of its rotation. The pitch angle of each of the blades is varied cyclically by mechanical means such that the blades experiences positive angles of attack at both the top and bottom positions of the azimuth cycle. The resulting time-varying lift and drag forces produced by each blade can be resolved into the vertical and horizontal directions. Varying the amplitude and phase of the cyclic blade pitch can be used to change the magnitude and direction of the net thrust vector produced by the cyclorotor. Compared to a conventional rotor, each spanwise blade element of a cyclorotor operates at similar aerodynamic conditions (i.e., at similar flow velocities, Reynolds numbers, and angles of incidence), and so the blades can be optimized to achieve the best aerodynamic efficiency. Moreover, because the blades are cyclically pitched once per revolution (1/rev), unsteady flow mechanisms may delay blade stall onset and in turn may augment the lift produced by the blades. Albeit proposed to MAV-scale, its use on large scale vehicles turns problematic, and we proposed in this paper to address their stopovers. Furthermore, since the thrust vector of a cyclorotor can be instantaneously set to any direction perpendicular to the rotational axis, a cyclorotor-based air vehicle may ultimately show better maneuverability and agility as compared to a classical powered conventional rotor system. One major drawback of a cyclorotor is its relatively large rotating structure which might offer a weight penalty when compared to a conventional rotor.

A Novel Look at the Performance of the Cyclorotor Propulsion System for Air Vehicles

2012 ◽  
Author(s):  
José C. Páscoa ◽  
Antonio Dumas ◽  
Michele Trancossi
Keyword(s):  
Large Scale ◽  
Reynolds Numbers ◽  
Unsteady Motion ◽  
Rotational Axis ◽  
Rotor Systems ◽  
Drag Forces ◽  
Blade Optimization ◽  
Weight Penalty ◽  
Lift And Drag ◽  
Rotating Wing

A system in which a rotating-wing device, comprising several pitching blades, turns around an axis along the span of the blades is called a cyclorotor. During the azimuthal rotation of the blades they also experience a change in the pitch angle. For each of the blades its pitch is varied cyclically by mechanical means such that the blades experience positive angles of attack at both the top and bottom positions of the azimuth cycle. The resultant unsteady motion of each blade can then be summed up into a resultant lift and drag forces. An almost instantaneous variation of magnitude and direction of the total cyclo rotor thrust can be obtained by changing the amplitude and phase of the cyclic blade pitch. In this rotor, conversely to classical propellers, each spanwise blade element operates at similar flow velocities, Reynolds numbers and incidence, this allows an easier blade optimization to achieve the best aerodynamic efficiency. Further, the cyclorotor is based on using dynamic pitching in order to delay stall and in this way increase the lift produced by the blades. Realistic flying vehicles have only be presented for the MAV-scale, its use on large scale vehicles turns problematic, herein we will analyze its stopovers. Finally, a very advantageous characteristic is the possibility to achieve almost instantaneous thrust variation in any direction perpendicular to the rotational axis, this will result in an air vehicle with a much better maneuverability, as compared with vehicles powered by classical rotor systems. This comes at a cost of a larger structure which might lead to a weight penalty.

scholarly journals Modeling and simulation of a spherical mobile robot

2010 ◽  
Vol 7 (1) ◽  
pp. 51-62 ◽  
Author(s):  
Shengju Sang ◽  
Zhao Jichao ◽  
Hao Wu ◽  
Shoujun Chen ◽  
Qi An
Keyword(s):  
Mobile Robot ◽  
Mathematical Models ◽  
Modeling And Simulation ◽  
3D Model ◽  
Matlab Simulink ◽  
Propulsion Mechanism ◽  
Actual Model ◽  
Spherical Mobile Robot ◽  
Novel Design

Spherical mobile robot (SMR) has been studied analytically and experimentally in this paper, a novel design with an internal propulsion mechanism and mathematical models of the robot's dynamics and kinematics are introduced. A 3D model of robot is built by SOLIDWORKS and then exported to ADAMS2007 for simulation. The results of simulation by combining MATLAB/SIMULINK with ADAMS are presented. It is shown experimentally that the behavior of actual model consist well with the prediction of simulation.

scholarly journals Scalable Output Linear Actuators, a Novel Design Concept Using Shape Memory Alloy Wires Driven by Fluid Temperature

Machines ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Andres Osorio Salazar ◽  
Yusuke Sugahara ◽  
Daisuke Matsuura ◽  
Yukio Takeda
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Angular Position ◽  
Scale Factor ◽  
Design Concept ◽  
Fluid Temperature ◽  
Step Size ◽  
Simple Method ◽  
Output Characteristics ◽  
Novel Design

In this paper, the concept of scalability for actuators is introduced and explored, which is the capability to freely change the output characteristics on demand: displacement and force for a linear actuator, angular position and torque for a rotational actuator. This change can either be used to obtain power improvement (with a constant scale factor), or to improve the usability of a robotic system according to variable conditions (with a variable scale factor). Some advantages of a scalable design include the ability to adapt to changing environments, variable resolution of step size, ability to produce designs that are adequate for restricted spaces or that require strict energy efficiency, and intrinsically safe systems. Current approaches for scalability in actuators have shortcomings: the method to achieve scalability is complex, so obtaining a variable scaling factor is challenging, or they cannot scale both output characteristics simultaneously. Shape Memory Alloy (SMA) wire-based actuators can overcome these limitations, because its two output characteristics, displacement and force, are physically independent from each other. In this paper we present a novel design concept for linear scalable actuators that overcome SMA design and scalability limitations by using a variable number of SMA wires mechanically in parallel, immersed in a liquid that transmits heat from a separate heat source (wet activation). In this concept, more wires increase the maximum attainable force, and longer wires increase the maximum displacement. Prototypes with different number of SMA wires were constructed and tested in isometric experiments to determine force vs. temperature behavior and time response. The heat-transmitting liquid was either static or flowing using pumps. Scalability was achieved with a simple method in all tested prototypes with a linear correlation of maximum force to number of SMA wires. Flowing heat transmission achieved higher actuation bandwidth.

scholarly journals Preliminary Results on the Dynamics of a Pile-Moored Fish Cage with Elastic Net in Currents and Waves

2020 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Gianluca Zitti ◽  
Nico Novelli ◽  
Maurizio Brocchini
Keyword(s):  
Numerical Model ◽  
Laboratory Experiments ◽  
Numerical Models ◽  
Offshore Structures ◽  
Fish Farm ◽  
Maximum Displacement ◽  
Drag Forces ◽  
Real Size ◽  
Lift And Drag ◽  
Mesh Grid

Over the last decades, the aquaculture sector increased significantly and constantly, moving fish-farm plants further from the coast, and exposing them to increasingly high forces due to currents and waves. The performances of cages in currents and waves have been widely studied in literature, by means of laboratory experiments and numerical models, but virtually all the research is focused on the global performances of the system, i.e., on the maximum displacement, the volume reduction or the mooring tension. In this work we propose a numerical model, derived from the net-truss model of Kristiansen and Faltinsen (2012), to study the dynamics of fish farm cages in current and waves. In this model the net is modeled with straight trusses connecting nodes, where the mass of the net is concentrated at the nodes. The deformation of the net is evaluated solving the equation of motion of the nodes, subjected to gravity, buoyancy, lift, and drag forces. With respect to the original model, the elasticity of the net is included. In this work the real size of the net is used for the computation mesh grid, this allowing the numerical model to reproduce the exact dynamics of the cage. The numerical model is used to simulate a cage with fixed rings, based on the concept of mooring the cage to the foundation of no longer functioning offshore structures. The deformations of the system subjected to currents and waves are studied.

scholarly journals SHIL and DHIL Simulations of Nonlinear Control Methods Applied for Power Converters Using Embedded Systems

Electronics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 241 ◽  
Author(s):  
Arthur Rosa ◽  
Matheus Silva ◽  
Marcos Campos ◽  
Renato Santana ◽  
Welbert Rodrigues ◽  
...  
Keyword(s):  
Embedded Systems ◽  
Nonlinear Control ◽  
Real Time ◽  
Digital Signal Processor ◽  
High Performance ◽  
Power Converters ◽  
Digital Signal ◽  
Simulation Method ◽  
Hardware In The Loop ◽  
Control Techniques

In this work, a new real-time Simulation method is designed for nonlinear control techniques applied to power converters. We propose two different implementations: in the first one (Single Hardware in The Loop: SHIL), both model and control laws are inserted in the same Digital Signal Processor (DSP), and in the second approach (Double Hardware in The Loop: DHIL), the equations are loaded in different embedded systems. With this methodology, linear and nonlinear control techniques can be designed and compared in a quick and cheap real-time realization of the proposed systems, ideal for both students and engineers who are interested in learning and validating converters performance. The methodology can be applied to buck, boost, buck-boost, flyback, SEPIC and 3-phase AC-DC boost converters showing that the new and high performance embedded systems can evaluate distinct nonlinear controllers. The approach is done using matlab-simulink over commodity Texas Instruments Digital Signal Processors (TI-DSPs). The main purpose is to demonstrate the feasibility of proposed real-time implementations without using expensive HIL systems such as Opal-RT and Typhoon-HL.

Computational Aerodynamics of a Winston-Cup-Series Race Car

2002 ◽  
Author(s):  
Oktay Baysal ◽  
Terry L. Meek
Keyword(s):  
Present Model ◽  
Pressure Coefficient ◽  
The Body ◽  
Race Car ◽  
Drag Forces ◽  
Surface Pressure Distribution ◽  
Computational Aerodynamics ◽  
Baseline Case ◽  
Quantitative Results ◽  
Lift And Drag

Since the goal of racing is to win and since drag is a force that the vehicle must overcome, a thorough understanding of the drag generating airflow around and through a race car is greatly desired. The external airflow contributes to most of the drag that a car experiences and most of the downforce the vehicle produces. Therefore, an estimate of the vehicle’s performance may be evaluated using a computational fluid dynamics model. First, a computer model of the race car was created from the measurements of the car obtained by using a laser triangulation system. After a computer-aided drafting model of the actual car was developed, the model was simplified by removing the tires, roof strakes, and modification of the spoiler. A mesh refinement study was performed by exploring five cases with different mesh densities. By monitoring the convergence of the computed drag coefficient, the case with 2 million elements was selected as being the baseline case. Results included flow visualization of the pressure and velocity fields and the wake in the form of streamlines and vector plots. Quantitative results included lift and drag, and the body surface pressure distribution to determine the centerline pressure coefficient. When compared with the experimental results, the computed drag forces were comparable but expectedly lower than the experimental data mainly attributable to the differences between the present model and the actual car.

Vibration Excitation Forces in a Normal Triangular Tube Bundle Subjected to Two-Phase Cross Flow

2011 ◽  
Author(s):  
E. S. Perrot ◽  
N. W. Mureithi ◽  
M. J. Pettigrew ◽  
G. Ricciardi
Keyword(s):  
Tube Bundle ◽  
Cross Flow ◽  
Random Excitation ◽  
Two Phase ◽  
Constant Frequency ◽  
Fluid Forces ◽  
Drag Forces ◽  
Wide Range ◽  
Drag And Lift ◽  
Lift And Drag

This paper presents test results of vibration forces in a normal triangular tube bundle subjected to air-water cross-flow. The dynamic lift and drag forces were measured with strain gage instrumented cylinders. The array has a pitch-to-diameter ratio of 1.5, and the tube diameter is 38 mm. A wide range of void fraction and fluid velocities were tested. The experiments revealed significant forces in both the drag and lift directions. Constant frequency and quasi-periodic fluid forces were found in addition to random excitation. These forces were analyzed and characterized to understand their origins. The forces were found to be dependent on the position of the cylinder within the bundle. The results are compared with those obtained with flexible cylinders in the same tube bundle and to those for a rotated triangular tube bundle. These comparisons reveal the influence of quasi-periodic forces on tube motions.

scholarly journals Design of Fixed-Wing and Multi-Copter Hybrid Drone System for Human Body Temperature Measurement during COVID-19 Pandemic

2021 ◽  
Vol 20 ◽  
pp. 31-39
Author(s):  
Zayed Almheiri ◽  
Rawan Aleid ◽  
Sharul Sham Dol
Keyword(s):  
Body Temperature ◽  
Temperature Measurement ◽  
Human Body ◽  
Equivalent Strain ◽  
Simulation Software ◽  
Operational Conditions ◽  
Drag Forces ◽  
Human Body Temperature ◽  
Body Temperature Measurement ◽  
Lift And Drag

The purpose of this research is to conduct aerodynamics study and design a hybrid drone system of fixed-wing and multi-copter. The mission of this drone is to measure human body temperature during COVID19 pandemic. The specific aim of the drone is to fly and cover larger industrial areas roughly about 50 km2 with longer flying time than the conventional drone, of about 1.5 hours. The applications of the simulation software such as XFLR5 and ANSYS have a big impact in identifying areas that need to be improved for the drone system. XFLR5 software was used to compare the characteristics of different airfoils with highest lift over drag, L/D ratio. Based on the airfoil selection, it was found that NACA 4412 airfoil produces the highest L/D ratio. The detailed geometry of the drone system includes a fuselage length of 1.9 meters and wingspan of 2 meters. Moreover, 10 sheets of solar panels were placed along the wing for sustainable flight operation to cover wider areas of mission. The structural analysis was done on ANSYS to test the elastic stress, equivalent strain, deformation, factor of safety pressure as well as lift and drag forces under various operational conditions and payloads. The landing gear was analyzed for harsh landing. ANSYS Computational Fluid Dynamics (CFD) was utilized to study the aerodynamics of the drone at different parameters such as the velocities and angles of attack during the operation. This design ensures the stability of the drone during the temperature measurement phase. The best thermal-imaging camera for such purpose would be the Vue Pro R 336, 45° radiometric drone thermal camera with a resolution of 640 x 512 pixels. This camera has the advantage of a permanent continuous out focus that give the ability of taking measurements even if there was changing on the altitude or any kind of vibrations.

Influence of wing kinematics on aerodynamic performance in hovering insect flight

2007 ◽  
Vol 594 ◽  
pp. 341-368 ◽  
Author(s):  
FRANK M. BOS ◽  
D. LENTINK ◽  
B. W. VAN OUDHEUSDEN ◽  
H. BIJL
Keyword(s):  
Insect Flight ◽  
Fruit Fly ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Insect Wing ◽  
Wing Kinematics ◽  
Drag Forces ◽  
Kinematic Models ◽  
Characteristic Features ◽  
Lift And Drag

The influence of different wing kinematic models on the aerodynamic performance of a hovering insect is investigated by means of two-dimensional time-dependent Navier–Stokes simulations. For this, simplified models are compared with averaged representations of the hovering fruit fly wing kinematics. With increasing complexity, a harmonic model, a Robofly model and two more-realistic fruit fly models are considered, all dynamically scaled at Re = 110. To facilitate the comparison, the parameters of the models were selected such that their mean quasi-steady lift coefficients were matched. Details of the vortex dynamics, as well as the resulting lift and drag forces, were studied.The simulation results reveal that the fruit fly wing kinematics result in forces that differ significantly from those resulting from the simplified wing kinematic models. In addition, light is shed on the effect of different characteristic features of the insect wing motion. The angle of attack variation used by fruit flies increases aerodynamic performance, whereas the deviation is probably used for levelling the forces over the cycle.

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