scholarly journals A semi-empirical model of the aerodynamics of manoeuvring insect flight

2021 ◽  
Vol 18 (177) ◽  
Author(s):  
Simon M. Walker ◽  
Graham K. Taylor
Keyword(s):  
Sagittal Plane ◽  
Insect Flight ◽  
Aerodynamic Force ◽  
Three Dimensional ◽  
Element Model ◽  
Parameter Estimates ◽  
Free Flight ◽  
Kinematic Data ◽  
Semi Empirical ◽  
Blade Element

Blade element modelling provides a quick analytical method for estimating the aerodynamic forces produced during insect flight, but such models have yet to be tested rigorously using kinematic data recorded from free-flying insects. This is largely because of the paucity of detailed free-flight kinematic data, but also because analytical limitations in existing blade element models mean that they cannot incorporate the complex three-dimensional movements of the wings and body that occur during insect flight. Here, we present a blade element model with empirically fitted aerodynamic force coefficients that incorporates the full three-dimensional wing kinematics of manoeuvring Eristalis hoverflies, including torsional deformation of their wings. The two free parameters were fitted to a large free-flight dataset comprising N = 26 541 wingbeats, and the fitted model captured approximately 80% of the variation in the stroke-averaged forces in the sagittal plane. We tested the robustness of the model by subsampling the data, and found little variation in the parameter estimates across subsamples comprising 10% of the flight sequences. The simplicity and generality of the model that we present is such that it can be readily applied to kinematic datasets from other insects, and also used for the study of insect flight dynamics.

scholarly journals A semi-empirical model of the aerodynamics of manoeuvring insect flight

2020 ◽  
Author(s):  
Simon M. Walker ◽  
Graham K. Taylor
Keyword(s):  
Sagittal Plane ◽  
Insect Flight ◽  
Aerodynamic Force ◽  
Three Dimensional ◽  
Element Model ◽  
Parameter Estimates ◽  
Free Flight ◽  
Kinematic Data ◽  
Semi Empirical ◽  
Blade Element

Blade element modelling provides a quick analytical method for estimating the aerodynamic forces produced during insect flight, but such models have yet to be tested rigorously using kinematic data recorded from free-flying insects. This is largely because of the paucity of detailed free-flight kinematic data, but also because analytical limitations in existing blade element models mean that they cannot incorporate the complex three-dimensional movements of the wings and body that occur during insect flight. Here, we present a blade element model with empirically-fitted aerodynamic force coefficients that incorporates the full three-dimensional wing kinematics of manoeuvring Eristalis hoverflies, including torsional deformation of their wings. The two free parameters were fitted to a large free-flight dataset comprising N = 26, 541 wingbeats, and the fitted model captured approximately 80% of the variation in the stroke-averaged forces in the sagittal plane. We tested the robustness of the model by subsampling the data, and found little variation in the parameter estimates across subsamples comprising 10% of the flight sequences. The simplicity and generality of the model that we present is such that it can be readily applied to kinematic datasets from other insects, and also used for the study of insect flight dynamics.

scholarly journals The Appropriateness of the Helical Axis Technique and Six Available Cardan Sequences for the Representation of 3-D Lead Leg Kinematics During the Fencing Lunge

2013 ◽  
Vol 37 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Jonathan Sinclair ◽  
Paul J Taylor ◽  
Lindsay Bottoms
Keyword(s):  
Repeated Measures ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Helical Axis ◽  
Kinematic Parameters ◽  
Kinematic Data ◽  
Intraclass Correlations ◽  
Common Technique ◽  
Rotation Plane ◽  
Leg Kinematics

Cardan/Euler angles represent the most common technique for the quantification of segmental rotations. Cardan angles are influenced by their ordered sequence, and sensitive to planar-cross talk from the dominant rotation plane, which may affect the angular parameters. The International Society of Biomechanics (ISB) currently recommends a sagittal, coronal, and then transverse (XYZ) ordered sequence, although it has been proposed that when quantifying non-sagittal rotations this may not be the most appropriate technique. This study examined the influence of the helical and six available Cardan sequences on lower extremity three-dimensional (3-D) kinematics of the lead leg during the fencing lunge. Kinematic data were obtained using a 3-D motion capture system as participants completed simulated lunges. Repeated measures ANOVAs were used to compare discrete kinematic parameters, and intraclass correlations were also utilized to determine evidence of planar crosstalk. The results indicate that in all three planes of rotation, peak angle and range of motion angles using the YXZ and ZXY sequences were significantly greater than the other sequences. It was also noted that the utilization of the YXZ and ZXY sequences was associated with the strongest correlations from the sagittal plane, and the XYZ sequence was found habitually to be associated with the lowest correlations. It appears that for accurate representation of 3-D kinematics of the lead leg during the fencing lunge, the XYZ sequence is the most appropriate and as such its continued utilization is encouraged.

Stress Analysis of the Polyethylene Component in Total Ankle Arthroplasty: Effect of Thickness

2003 ◽  
Author(s):  
Karol Galik ◽  
Patrick Smolinski ◽  
Stephen F. Conti ◽  
Mark C. Miller
Keyword(s):  
Contact Pressure ◽  
Sagittal Plane ◽  
Distal Tibia ◽  
Three Dimensional ◽  
Vertical Direction ◽  
Element Model ◽  
Polyethylene Liner ◽  
Minimal Thickness ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

A three-dimensional finite element model was constructed of the distal tibia and fibula and a semi-constrained ankle prosthesis (Agility™ system). Contact elements were used at the interface between the talar component and the polyethylene liner and the proximal tibia and fibular were loaded in the in vertical direction. The minimal thickness of the polyethylene liner was varied from 3 mm to 8 mm in 1 mm increments. The results showed that the liner contact pressure in the sagittal plane mid-line decreased from 20 MPa to 14 MPa with increasing thickness while the medial edge contact pressure increased from 26 MPa to 30 MPa.

scholarly journals Cycling kinematics in healthy adults for musculoskeletal rehabilitation guidance

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Haeun Yum ◽  
Hyang Kim ◽  
Taeyong Lee ◽  
Moon Seok Park ◽  
Seung Yeol Lee
Keyword(s):  
Sagittal Plane ◽  
External Rotation ◽  
Age Groups ◽  
Three Dimensional ◽  
Healthy Adults ◽  
Postoperative Rehabilitation ◽  
Kinematic Data ◽  
Average Value ◽  
The Right ◽  
Musculoskeletal Rehabilitation

Abstract Background Stationary cycling is commonly used for postoperative rehabilitation of physical disabilities; however, few studies have focused on the three-dimensional (3D) kinematics of rehabilitation. This study aimed to elucidate the three-dimensional lower limb kinematics of people with healthy musculoskeletal function and the effect of sex and age on kinematics using a controlled bicycle configuration. Methods Thirty-one healthy adults participated in the study. The position of the stationary cycle was standardized using the LeMond method by setting the saddle height to 85.5% of the participant’s inseam. The participants maintained a pedaling rate of 10–12 km/h, and the average value of three successive cycles of the right leg was used for analysis. The pelvis, hip, knee, and ankle joint motions during cycling were evaluated in the sagittal, coronal, and transverse planes. Kinematic data were normalized to 0–100% of the cycling cycle. The Kolmogorov-Smirnov test, Mann-Whitney U test, Kruskal-Wallis test, and k-fold cross-validation were used to analyze the data. Results In the sagittal plane, the cycling ranges of motion (ROMs) were 1.6° (pelvis), 43.9° (hip), 75.2° (knee), and 26.9° (ankle). The coronal plane movement was observed in all joints, and the specific ROMs were 6.6° (knee) and 5.8° (ankle). There was significant internal and external rotation of the hip (ROM: 11.6°), knee (ROM: 6.6°), and ankle (ROM: 10.3°) during cycling. There was no difference in kinematic data of the pelvis, hip, knee, and ankle between the sexes (p = 0.12 to 0.95) and between different age groups (p = 0.11 to 0.96) in all anatomical planes. Conclusions The kinematic results support the view that cycling is highly beneficial for comprehensive musculoskeletal rehabilitation. These results might help clinicians set a target of recovery ROM based on healthy and non-elite individuals and issue suitable guidelines to patients.

Aeromechanics of passive rotation in flapping flight

2010 ◽  
Vol 660 ◽  
pp. 197-220 ◽  
Author(s):  
J. P. WHITNEY ◽  
R. J. WOOD
Keyword(s):  
Aerodynamic Force ◽  
Equations Of Motion ◽  
Beat Frequency ◽  
Element Model ◽  
Rotational Dynamics ◽  
Model Parameters ◽  
Passive Rotation ◽  
Out Of Plane ◽  
Three Degree Of Freedom ◽  
Blade Element

Flying insects and robots that mimic them flap and rotate (or ‘pitch’) their wings with large angular amplitudes. The reciprocating nature of flapping requires rotation of the wing at the end of each stroke. Insects or flapping-wing robots could achieve this by directly exerting moments about the axis of rotation using auxiliary muscles or actuators. However, completely passive rotational dynamics might be preferred for efficiency purposes, or, in the case of a robot, decreased mechanical complexity and reduced system mass. Herein, the detailed equations of motion are derived for wing rotational dynamics, and a blade-element model is used to supply aerodynamic force and moment estimates. Passive-rotation flapping experiments with insect-scale mechanically driven artificial wings are conducted to simultaneously measure aerodynamic forces and three-degree-of-freedom kinematics (flapping, rotation and out-of-plane deviation), allowing a detailed evaluation of the blade-element model and the derived equations of motion. Variations in flapping kinematics, wing-beat frequency, stroke amplitude and torsional compliance are made to test the generality of the model. All experiments showed strong agreement with predicted forces and kinematics, without variation or fitting of model parameters.

The wing beat of Drosophila Melanogaster . II. Dynamics

1990 ◽  
Vol 327 (1238) ◽  
pp. 19-44 ◽  
Keyword(s):  
Drosophila Melanogaster ◽  
Three Dimensional ◽  
Laser Interferometry ◽  
Longitudinal Axis ◽  
Wing Beat ◽  
Average Force ◽  
Kinematic Data ◽  
Blade Element Theory ◽  
Element Theory ◽  
Blade Element

The wing beat of tiny insects has attracted considerable interest because conventional aerodynamics predicts a reduction of flight efficiency when aerofoils are comparatively small and slow. Here, two approaches are reported by which we investigated the dynamics of the wing beat of tethered flying Drosophila melanogaster . First, the forces acting on the moving wing were calculated from three-dimensional kinematic data, following the blade-element theory which assumes quasi-steady aerodynamics. Under these conditions, the flight force is directed upwards, relative to the longitudinal body axis, during the second half of the downstroke; it is oriented forwards and downwards during the upstroke. The time average of the force generated according to this theory does not correspond to the direction and magnitude of the actual average force of flight. The expected force is directed forwards, along the body’s longitudinal axis, and is too small to keep the fly airborne. Secondly, an attempt is made to measure the timecourse of flight forces by attaching the fly to along the body’s longitudinal axis, and is too small to keep the fly airborne. Secondly, an attempt is made to measure the timecourse of flight forces by attaching the fly to a string, the displacement of which is monitored by means of laser interferometry. A sharp lift-pulse is observed when the wing is rapidly rotated during the ventral reversal of the wing-beat cycle. A second lift maximum of variable strength seems to be associated with the squeeze-peel events during the dorsal reversal. These results support the notion that flight in small insects might be dominated by unsteady mechanisms.

Minimal Kinematic Model for Inverse Dynamic Analysis of Gait

2014 ◽  
Author(s):  
D. S. Mohan Varma ◽  
S. Sujatha
Keyword(s):  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Center Of Mass ◽  
Reaction Force ◽  
Kinematic Model ◽  
Parameter Estimates ◽  
Dynamics Model ◽  
Kinematic Data ◽  
Segment Model ◽  
Internal Joint

The objective of this work is to develop an inverse dynamics model that uses minimal kinematic inputs to estimate the ground reaction force (GRF). The human body is modeled with 14 rigid segments and a circular ankle-foot-roll-over shape (AFROS) for the foot-ground interaction. The input kinematic data and body segment parameter estimates are obtained from literature. Optimization is used to ensure that the kinematic data satisfy the constraint that the swing leg clears the ground in the single support (SS) phase. For the SS phase, using the segment angles as the generalized degrees of freedom (DOF), the kinematic component of the GRF is expressed analytically as the summation of weighted kinematics of individual segments. The weighting functions are constants that are functions of the segment masses and center of mass distances. Using this form of the equation for GRF, it is seen that the kinematics of the upper body segments do not contribute to the vertical component GRFy in SS phase enabling the reduction of a 16-DOF 14-segment model to a 10-DOF 7-segment model. It is seen that the model can be further reduced to a 3-DOF model for GRFy estimation in the SS phase of gait. The horizontal component GRFx is computed assuming that the net GRF vector passes through the center of mass (CoM). The GRF in double support phase is assumed to change linearly from one foot to the other. The sagittal plane internal joint forces and moments acting at the ankle, knee and hip are computed using the 3-DOF model and the 10-DOF model and compared with the results from literature. An AFROS and measurements of the stance shank and thigh rotations in the sagittal plane, and of the lower trunk (or pelvis) in the frontal plane provide sufficient kinematics in an inverse dynamics model to estimate the GRF and joint reaction forces and moments. Such a model has the potential to simplify gait analysis.

Location of the Centre of Resistance for the Nasomaxillary Complex Studied in a Three-Dimensional Finite Element Model

1995 ◽  
Vol 22 (3) ◽  
pp. 227-232 ◽  
Author(s):  
Kazuo Tanne ◽  
Susumu Matsubara ◽  
Mamoru Sakuda
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Sagittal Plane ◽  
Three Dimensional ◽  
Vertical Plane ◽  
Element Model ◽  
Occlusal Plane ◽  
Dimensional Finite Element ◽  
Plane Passing ◽  
Three Dimensional Finite Element

The purpose of this study was to investigate the location of the centre of resistance (CRe) for the nasomaxillary complex by the use of finite element analysis. A three-dimensional finite element model of the craniofacial complex, consisting of 2918 nodes and 1776 elements, was used for displacement analyses. Anteriorly and inferiorly directed forces of 9·8 N were applied at five different levels, parallel and perpendicular to the functional occlusal plane, respectively. For each loading condition, horizontal and vertical displacements of eight anatomic points in the complex and on the maxillary dentition were analysed. The complex exhibited an almost translatory displacement of approximately 1·0 µm in the forward direction when the horizontal force was applied at a point on the horizontal plane, passing through the superior ridge of the pterygomaxillary fissure, whereas the complex experienced clockwise or counter clockwise rotation when the forces were applied at the remaining levels. Furthermore, the downward forces produced anteriorly upward, or posteriorly upward rotation. However, the force applied at a point on the vertical plane passing through the posterior wall of the pterygomaxillary fissure, produced almost equal displacements of approximately 6·0 µm in an inferior direction for all the anatomic points. It is suggested that CRe of the nasomaxillary complex is located on the posterosuperior ridge of the pterygomaxillary fissure, registered on the median sagittal plane.

An Investigation on the Issues in Modelling of Free Flight in Animal Locomotion

2011 ◽  
Author(s):  
Masateru Maeda ◽  
Toshiyuki Nakata ◽  
Hao Liu
Keyword(s):  
Rigid Body ◽  
Degrees Of Freedom ◽  
Aerodynamic Force ◽  
Three Dimensional ◽  
Micro Air Vehicles ◽  
Rigid Body Dynamics ◽  
Free Flight ◽  
Comprehensive Investigation ◽  
Body Dynamics ◽  
Generation Mechanisms

Aiming at establishing an effective computational framework to accurately predict free-flying dynamics and aerodynamics we here present a comprehensive investigation on some issues associated with the modelling of free flight. Free flight modelling/simulation is essential for some types of flights e.g. falling leaves or auto-rotating seeds for plants; unsteady manoeuvres such as take-off, turning, or landing for animals. In addition to acquiring the deeper understanding of the flight biomechanics of those natural organisms, revealing the sophisticated aerodynamic force generation mechanisms employed by them may be useful in designing man-made flying-machines such as rotary or flapping micro air vehicles (MAVs). The simulations have been conducted using the coupling of computational fluid dynamics (CFD) and rigid body dynamics, thus achieving the free flight. The flow field is computed with a three-dimensional unsteady incompressible Navier-Stokes solver using pseudo-compressibility and overset gird technique. The aerodynamic forces acting on the flyer are calculated by integrating the forces on the surfaces. Similarly, the aerodynamic torque around the flyer’s centre of mass is obtained. The forces and moments are then introduced into a six degrees-of-freedom rigid body dynamics solver which utilises unit quaternions for attitude description in order to avoid singular attitude. Results are presented of a single body model and some insect-like multi-body models with flapping wings, which point to the importance of free-flight modelling in systematic analyses of flying aerodynamics and manoeuvrability. Furthermore, a comprehensive investigation indicates that the framework is capable to predict the aerodynamic performance of free-flying or even free-swimming animals in an intermediate range of Reynolds numbers (< 105).

scholarly journals Cycling Kinematics in Healthy Adults for Musculoskeletal Rehabilitation Guidance

2021 ◽  
Author(s):  
Haeun Yum ◽  
Hyang Kim ◽  
Taeyong Lee ◽  
Moon Seok Park ◽  
Seung Yeol Lee
Keyword(s):  
Sagittal Plane ◽  
External Rotation ◽  
Three Dimensional ◽  
Healthy Adults ◽  
Postoperative Rehabilitation ◽  
Kinematic Data ◽  
Average Value ◽  
The Right ◽  
Joint Motions ◽  
Musculoskeletal Rehabilitation

Abstract Background: Stationary cycling is commonly used for postoperative rehabilitation of physical disabilities, but few studies have focused on the three-dimensional (3D) kinematics of rehabilitation. This study aimed to elucidate the three-dimensional lower limb kinematics of musculoskeletally healthy people and the effect of sex and age on kinematics using a controlled bicycle configuration.Methods: Thirty-one healthy adults participated in the study. The stationary cycle positioning was standardized using the LeMond method by setting the saddle height to 85.5% of the participant’s inseam. The participants maintained a pedaling rate of 10–12 km/h, and the average value of three successive cycles of the right leg was used for analysis. The pelvis, hip, knee, and ankle joint motions during cycling were evaluated in the sagittal, coronal, and transverse planes. Kinematic data were normalized to 0–100% of the cycling cycle. The Kolmogorov-Smirnov test, Mann-Whitney U test, Kruskal-Wallis test, and k-fold cross-validation were used to analyze the data.Results: In the sagittal plane, the cycling ranges of motion (ROMs) were 1.6° (pelvis), 43.9° (hip), 75.2° (knee), and 26.9° (ankle). The coronal plane movement was observed in all joints, and the specific ROMs were 6.6° (knee) and 5.8° (ankle). There was significant internal and external rotation of the hip (ROM: 11.6°), knee (ROM: 6.6°), and ankle (ROM: 10.3°) during cycling. There was no difference in kinematic data of the pelvis, hip, knee, and ankle between sexes (p = 0.12 to 0.95) and among ages (p = 0.11 to 0.96) in all anatomical planes.Conclusions: The kinematic results support the assertion that cycling is highly recommended for comprehensive musculoskeletal rehabilitation. These results may help clinicians choose a target recovery ROM based on healthy and non-elite individuals and issue suitable guidelines to patients.

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