scholarly journals Gap perception in bumblebees

2018 ◽  
Author(s):  
Sridhar Ravi ◽  
Olivier Bertrand ◽  
Tim Siesenop ◽  
Lea-Sophie Manz ◽  
Charlotte Doussot ◽  
...  
Keyword(s):  
Optic Flow ◽  
Physical Environment ◽  
Longitudinal Velocity ◽  
Flight Tunnel ◽  
Flight Path ◽  
Flight Trajectory ◽  
Lateral Velocity ◽  
Environmental Features ◽  
Aerial Navigation ◽  
Lateral Displacements

AbstractA number of insects fly over long distances below the natural canopy where the physical environment is highly cluttered consisting of obstacles of varying shape, size and texture. While navigating within such environments animals need to perceive and disambiguate environmental features that might obstruct their flight. The most elemental aspect of aerial navigation through such environments is gap identification and passability evaluation. We used bumblebees to seek insights into the mechanisms used for gap identification when confronted with an obstacle in their flight path and behavioral compensations employed to assess gap properties. Initially, bumblebee foragers were trained to fly though an unobstructed flight tunnel that led to a foraging chamber. After the bees were familiar with this situation, we placed a wall containing a gap that unexpectedly obstructed the flight path on a return trip to the hive. The flight trajectories of the bees as they approached the obstacle wall and traversed the gap were analyzed in order to evaluate their behavior as a function of the distance between the gap and a background wall that was placed behind the gap. Bumblebees initially decelerate when confronted with an unexpected obstacle. Deceleration was first noticed when the obstacle subtended around 35° on the retina but also depended on the properties of the gap. Subsequently the bees gradually traded off their longitudinal velocity to lateral velocity and approached the gap increasing lateral displacements and lateral velocity. Bumblebees shaped their flight trajectory depending on the salience of the gap, in our case, indicated by the optic flow contrast between the region within the gap and on the obstacle, which increases with decreasing distance between the gap and the background wall. As the optic flow contrast decreased the bees spent increasing time moving laterally across the obstacles. During these repeated lateral maneuvers the bees are likely assessing gap geometry and passability.

Understanding the Lateral Dimension of Traffic: Measuring and Modeling Lane Discipline

2021 ◽  
pp. 036119812110318
Author(s):  
Rafael Delpiano
Keyword(s):  
New Technologies ◽  
Autonomous Vehicle ◽  
Longitudinal Velocity ◽  
Lateral Position ◽  
Multiple Cameras ◽  
Lateral Velocity ◽  
Lane Changing ◽  
Lateral Dimension ◽  
Vehicle Position ◽  
Longitudinal Position

There is growing interest in understanding the lateral dimension of traffic. This trend has been motivated by the detection of phenomena unexplained by traditional models and the emergence of new technologies. Previous attempts to address this dimension have focused on lane-changing and non-lane-based traffic. The literature on vehicles keeping their lanes has generally been limited to simple statistics on vehicle position while models assume vehicles stay perfectly centered. Previously the author developed a two-dimensional traffic model aiming to capture such behavior qualitatively. Still pending is a deeper, more accurate comprehension and modeling of the relationships between variables in both axes. The present paper is based on the Next Generation SIMulation (NGSIM) datasets. It was found that lateral position is highly dependent on the longitudinal position, a phenomenon consistent with data capture from multiple cameras. A methodology is proposed to alleviate this problem. It was also discovered that the standard deviation of lateral velocity grows with longitudinal velocity and that the average lateral position varies with longitudinal velocity by up to 8 cm, possibly reflecting greater caution in overtaking. Random walk models were proposed and calibrated to reproduce some of the characteristics measured. It was determined that drivers’ response is much more sensitive to the lateral velocity than to position. These results provide a basis for further advances in understanding the lateral dimension. It is hoped that such comprehension will facilitate the design of autonomous vehicle algorithms that are friendlier to both passengers and the occupants of surrounding vehicles.

Effect of the Fish-Bone Dam Angle on the Flow Mechanisms of a Fish-Bone Type Dividing Dike

2020 ◽  
Vol 54 (3) ◽  
pp. 58-67
Author(s):  
Jia Ni ◽  
Linwei Wang ◽  
Xixian Chen ◽  
Luan Luan Xue ◽  
Isam Shahrour
Keyword(s):  
Water Level ◽  
Longitudinal Velocity ◽  
Flow Characteristics ◽  
Fish Bone ◽  
Flume Experiments ◽  
Lateral Velocity ◽  
Engineering Structures ◽  
Flow Mechanisms ◽  
River Training ◽  
Large Velocity Gradient

AbstractFish-bone type dividing dikes are river engineering structures used for river training and to protect a mid-channel bar from scour. The flow characteristics around fish-bone type dividing dikes are very complicated, especially near its fish-bone dam. To understand the flow and scour processes associated with fish-bone dams, this paper conducts a numerical simulation of flow characteristics for different fish-bone dam angles. Based on the Yudaizhou fish-bone type dividing dike of the Dongliu Waterway, a 3-D numerical model is established via Flow-3D to simulate the flow characteristics around a fish-bone type dividing dike, which is verified by flume experiments. Based on the results, the effects of different fish-bone dam angles on water level and velocity distribution are investigated. With increasing fish-bone dam angle, the longitudinal and lateral gradients of the water level gradually decreased, and the variation degree of the longitudinal velocity also decreased; however, the variation degree of the lateral velocity increased. Vortex areas formed around the fish-bone dam and the downstream zone of the dike. A large velocity gradient was found around the dike, and the downstream vortex area decreased with increasing fish-bone dam angle.

scholarly journals Vehicle Velocity Estimation Fusion with Kinematic Integral and Empirical Correction on Multi-Timescales

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1242
Author(s):  
Jiangyi Lv ◽  
Hongwen He ◽  
Wei Liu ◽  
Yong Chen ◽  
Fengchun Sun
Keyword(s):  
Autonomous Vehicles ◽  
Estimation Error ◽  
Longitudinal Velocity ◽  
Estimation Method ◽  
Velocity Estimation ◽  
Model Parameters ◽  
Lateral Velocity ◽  
Empirical Correction ◽  
Vehicle Velocity ◽  
Wide Range

Accurate and reliable vehicle velocity estimation is greatly motivated by the increasing demands of high-precision motion control for autonomous vehicles and the decreasing cost of the required multi-axis IMU sensors. A practical estimation method for the longitudinal and lateral velocities of electric vehicles is proposed. Two reliable driving empirical judgements about the velocities are extracted from the signals of the ordinary onboard vehicle sensors, which correct the integral errors of the corresponding kinematic equations on a long timescale. Meanwhile, the additive biases of the measured accelerations are estimated recursively by comparing the integral of the measured accelerations with the difference of the estimated velocities between the adjacent strong empirical correction instants, which further compensates the kinematic integral error on short timescale. The algorithm is verified by both the CarSim-Simulink co-simulation and the controller-in-the-loop test under the CarMaker-RoadBox environment. The results show that the velocities can be accurately and reliably estimated under a wide range of driving conditions without prior knowledge of the tire-model and other unavailable signals or frequently changeable model parameters. The relative estimation error of the longitudinal velocity and the absolute estimation error of the lateral velocity are kept within 2% and 0.5 km/h, respectively.

Observer-based state-feedback robust control for path following of autonomous ground vehicles

2019 ◽  
Vol 234 (2) ◽  
pp. 222-239 ◽  
Author(s):  
Pengpeng Feng ◽  
Jianwu Zhang ◽  
Weimiao Yang
Keyword(s):  
State Feedback ◽  
Longitudinal Velocity ◽  
Path Following ◽  
Linear Matrix ◽  
Ground Vehicles ◽  
Parameter Uncertainties ◽  
Lateral Velocity ◽  
External Disturbances ◽  
Static State ◽  
Autonomous Ground Vehicles

In this article, a robust [Formula: see text] observer-based static state-feedback controller is designed for the path following of autonomous ground vehicles. The Takagi–Sugeno fuzzy modeling technique is used for modeling of vehicle dynamics with varying longitudinal velocity first. Then considering the high cost of direct lateral velocity measurement, an observer is designed to estimate the value of lateral velocity. Meanwhile, a robust controller is proposed to deal with the parameter uncertainties and external disturbances simultaneously, including the variation of the tire-cornering stiffness of both front and rear tires. Afterward, the condition of designing such an observer-based controller is transformed into the feasible problem of linear matrix inequalities. Numerical simulations using a high-fidelity and full vehicle model are performed based on a Carsim–Simulink joint platform. Simulation results under different conditions and comparison with other controller show that the proposed controller is effective irrespective of the variation in the road condition, the change in the vehicle longitudinal velocity and the external disturbances.

How do athletes cause ball flight path deviation in high-performance interceptive ball sports? A systematic review

2021 ◽  
pp. 174795412110473
Author(s):  
Cody Lindsay ◽  
Brad Clark ◽  
Kane Middleton ◽  
Rian Crowther ◽  
Wayne Spratford
Keyword(s):  
Systematic Review ◽  
High Performance ◽  
Flight Path ◽  
Flight Trajectory ◽  
Task Constraints ◽  
Axis Of Rotation ◽  
Vertical Changes ◽  
Ball Flight ◽  
Change Task ◽  
Path Deviation

Athletes alter ball flight trajectory in interceptive ball sports to change task constraints that their opponents must overcome to successfully meet the ball in flight. This systematic review identified how athletes change their techniques to alter the ball flight trajectory in high-performance interceptive sports where the ball is projected by the hand towards an opponent. Studies that reported the kinematics or ball flight characteristics of these movements were searched for using SportsDiscus, Scopus, MEDLINE and CINAHL Plus databases up to 27 April 2021. Forty-eight articles met the inclusion criteria, including 19 baseball, 12 cricket, five handball, four softball, three volleyball and five water polo studies. Extracted data were presented as ranges and descriptively analysed to report athlete sporting actions. Trajectory deviation can be caused by imparting an altered seam orientation or spin rate and axis of rotation on the ball. Athletes impart sidespin or manipulate seam orientation to cause lateral deviation while topspin and backspin are used to create vertical changes in the flight path. Adjusting the shoulder, forearm, wrist, hand and fingers of the throwing or striking arm can be used to impart an altered seam orientation or spin rate and axis of rotation on the ball. The findings of this review could assist coaches and athletes across a variety of sports to improve the ability to deviate the ball during flight.

scholarly journals EVALUATION OF SMALL UNMANNED AIRCRAFT FLIGHT TRAJECTORY ACCURACY / IŠORINIŲ FAKTORIŲ ĮTAKOS NEDIDELIO AUTONOMINIO ORLAIVIO SKRYDŽIO TRAJEKTORIJOS TIKSLUMUI VERTINIMAS

2014 ◽  
Vol 6 (5) ◽  
pp. 577-582
Author(s):  
Ramūnas Kikutis ◽  
Jonas Stankūnas
Keyword(s):  
Theoretical Calculations ◽  
High Reliability ◽  
Unmanned Aircraft ◽  
Flight Path ◽  
Flight Trajectory ◽  
Circular Trajectory ◽  
Aircraft Flight ◽  
Air Space ◽  
Wind Influence ◽  
Main Factors

Today small unmanned aircraft are being more widely adapted for practical tasks. These tasks require high reliability and flight path accuracy. For such aircraft we have to deal with the chalenge how to compensate external factors and how to ensure the accuracy of the flight trajectory according to new regulations and standards. In this paper, new regulations for the flights of small unmanned aircraft in Lithuanian air space are discussed. Main factors, which affect errors of the autonomous flight path tracking, are discussed too. The emphasis is on the wind factor and the flight path of Dubbin’s trajectories. Research was performed with mathematical-dynamic model of UAV and it was compared with theoretical calculations. All calculations and experiments were accomplished for the circular part of Dubbin’s paths when the airplane was trimmed for circular trajectory flight in calm conditions. Further, for such flight the wind influence was analysed. Nedideli autonominiai orlaiviai yra vis plačiau pritaikomi praktinėms užduotims, kurioms reikalingas aukštas skrydžio patikimumas bei trajektorijos tikslumas, vykdyti. Kuriant bei naudojant tokius orlaivius, reikia vertinti egzistuojančių standartų bei taisyklių reikalavimus ir išorinių faktorių įtaką skrydžių trajektorijos tikslumui. Darbe aptariamos naujausios skrydžių autonominiais orlaiviais Lietuvoje taisyklės bei pagrindiniai faktoriai, darantys įtaką skrydžio trajektorijos paklaidoms. Darbe didžiausias dėmesys skirtas vėjo faktoriaus įtakos skrydžio trajektorijai vertinti, kai automatinio valdymo sistema nesiima koreguojamųjų veiksmų. Tyrimas atliktas remiantis teoriniais skaičiavimais bei traktuojant, kad orlaivis – taškinis kūnas. Šie rezultatai palyginti su gautaisiais panaudojus orlaivio dinaminį modelį.

4WID In-Wheel Motor EV Driving State Estimation Based on UKF

2012 ◽  
Vol 246-247 ◽  
pp. 712-717
Author(s):  
Gang Li ◽  
Chang Fu Zong ◽  
Qiang Zhang ◽  
Wei Hong
Keyword(s):  
State Estimation ◽  
Electric Vehicles ◽  
Simulation Experiment ◽  
Unscented Kalman Filter ◽  
Longitudinal Velocity ◽  
Estimation Algorithm ◽  
Slip Angle ◽  
Tire Model ◽  
Estimation Model ◽  
Lateral Velocity

According to the characteristics of the four independent drive (4WID) electric vehicles, the vehicle driving state estimation algorithm was designed based on the Unscented Kalman Filter (UKF). The algorithm used 3-DOF vehicle estimation model with the HSRI tire model. The 4WID EV longitudinal velocity, lateral velocity and side slip angle were estimated. The algorithm was verified through simulation experiment. The results showed that the algorithm could estimate the vehicle driving state more accurately.

scholarly journals Optimization of an aircraft flight trajectory in the GLONASS dynamic accuracy field

2019 ◽  
Vol 22 (5) ◽  
pp. 19-31
Author(s):  
O. N. Skrypnik ◽  
E. E. Nechaev ◽  
N. G. Arefyeva ◽  
R. O. Arefyev
Keyword(s):  
Traffic Management ◽  
Flight Path ◽  
Navigation Systems ◽  
Field Variation ◽  
Flight Trajectory ◽  
Aircraft Flight ◽  
Geometric Dilution Of Precision ◽  
Satellite Navigation Systems ◽  
The Cost ◽  
Theory Of Graphs

The authors consider the problem of optimization of aircraft flight trajectories in air traffic management (ATM) on the basis of flexible routing technologies which involve the use of satellite navigation systems (SNS). It is shown that in optimizing a trajectory it is necessary to take into account the accuracy of track holding during the flight which depends on the accuracy of the navigation system and external flight path disturbances, e.g. wind. For solving the task of optimization the authors propose to use the theory of graphs. The technique of constructing a dynamic SNS accuracy field and representing it as a graph was developed. It is proposed that the SNS field be characterized by geometric dilution of precision changing both in space and in time. Based on the theory of graphs (A-star algorithm) the technique of constructing a trajectory of optimal length with changing the SNS accuracy and external flight path disturbances is proposed. The criterion of optimization based on minimizing the true track is offered. The cost function taking into account the track holding accuracy in navigating by SNS and effects of external flight disturbances is justified. The article presents the results of A-star algorithm application for constructing an optimal flight trajectory under conditions of SNS accuracy field variation and presence of prohibited zones in the provided airspace.

scholarly journals Oscillations make a self-scaled model for honeybees’ visual odometer reliable regardless of flight trajectory

2021 ◽  
Vol 18 (182) ◽  
pp. 20210567
Author(s):  
Lucia Bergantin ◽  
Nesrine Harbaoui ◽  
Thibaut Raharijaona ◽  
Franck Ruffier
Keyword(s):  
Optic Flow ◽  
Food Source ◽  
Flow Model ◽  
Large Range ◽  
Waggle Dance ◽  
Flight Trajectory ◽  
Scaled Model ◽  
Statistical Dispersion ◽  
Visual Odometer ◽  
Robotic Applications

Honeybees foraging and recruiting nest-mates by performing the waggle dance need to be able to gauge the flight distance to the food source regardless of the wind and terrain conditions. Previous authors have hypothesized that the foragers’ visual odometer mathematically integrates the angular velocity of the ground image sweeping backward across their ventral viewfield, known as translational optic flow. The question arises as to how mathematical integration of optic flow (usually expressed in radians/s) can reliably encode distances, regardless of the height and speed of flight. The vertical self-oscillatory movements observed in honeybees trigger expansions and contractions of the optic flow vector field, yielding an additional visual cue called optic flow divergence. We have developed a self-scaled model for the visual odometer in which the translational optic flow is scaled by the visually estimated current clearance from the ground. In simulation, this model, which we have called SOFIa, was found to be reliable in a large range of flight trajectories, terrains and wind conditions. It reduced the statistical dispersion of the estimated flight distances approximately 10-fold in comparison with the mathematically integrated raw optic flow model. The SOFIa model can be directly implemented in robotic applications based on minimalistic visual equipment.

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