Analysis and Synthesis of Multi-Rotor Aerial Vehicles

2011 ◽  
Author(s):  
Qimi Jiang ◽  
Daniel Mellinger ◽  
Christine Kappeyne ◽  
Vijay Kumar
Keyword(s):  
Experimental Studies ◽  
Force Distribution ◽  
Force Analysis ◽  
Analysis And Synthesis ◽  
Angular Velocities ◽  
Aerial Vehicle ◽  
Position And Orientation ◽  
Configuration Synthesis ◽  
Save Energy ◽  
Optimal Set

This work addresses two basic problems of the multi-rotor aerial vehicle (MRAV). The first problem is the force analysis of the rotors. In order to save energy and maximize the lifetime of a given MRAV, the force distribution of the rotors is analyzed. As a result, an optimal set of angular velocities is obtained. The second problem is the configuration synthesis of the MRAV. In order to maximize the acceleration and improve the maneuverability of the MRAV, the geometric configuration (position and orientation) of the rotors is synthesized. The approaches for analysis and synthesis are presented and demonstrated by several case studies. The obtained results can be applied in the design of the MRAV and used as a guide for experimental studies.

A New View on Grasping

Motor Control ◽  
1999 ◽  
Vol 3 (3) ◽  
pp. 237-271 ◽  
Author(s):  
Jeroen B.J. Smeets ◽  
Eli Brenner
Keyword(s):  
Surface Roughness ◽  
Visual Information ◽  
Experimental Studies ◽  
Movement Speed ◽  
Object Size ◽  
Extensive Review ◽  
Minimum Jerk ◽  
Alternative Description ◽  
Position And Orientation ◽  
Shape And Size

Reaching out for an object is often described as consisting of two components that are based on different visual information. Information about the object's position and orientation guides the hand to the object, while information about the object's shape and size determines how the fingers move relative to the thumb to grasp it. We propose an alternative description, which consists of determining suitable positions on the object—on the basis of its shape, surface roughness, and so on—and then moving one's thumb and fingers more or less independently to these positions. We modeled this description using a minimum-jerk approach, whereby the finger and thumb approach their respective target positions approximately orthogonally to the surface. Our model predicts how experimental variables such as object size, movement speed, fragility, and required accuracy will influence the timing and size of the maximum aperture of the hand. An extensive review of experimental studies on grasping showed that the predicted influences correspond to human behavior.

Airborne Infection Isolation Rooms – A Review of Experimental Studies

2011 ◽  
Vol 20 (6) ◽  
pp. 584-594 ◽  
Author(s):  
Marko Hyttinen ◽  
Anna Rautio ◽  
Pertti Pasanen ◽  
Tiina Reponen ◽  
G. Scott Earnest ◽  
...  
Keyword(s):  
Disease Transmission ◽  
Experimental Studies ◽  
Air Leakage ◽  
Crucial Issue ◽  
Actual Knowledge ◽  
Airborne Infection ◽  
The Us ◽  
Air Cleaners ◽  
Long Time ◽  
Save Energy

Ventilation guidelines for airborne infection isolation rooms (AIIRs) are highly variable in different countries indicating lack of actual knowledge about the guidance needed. However, US guidelines for AIIRs are extensive and have been widely adopted outside the US. AIIR performance has also been evaluated in numerous studies. For a long time, the aim has mainly been to evaluate how well the existing AIIRs meet US guidelines. For historical reasons, mixing-type ventilation has been emphasised and attention has been paid to air exchange rates, although the use of auxiliary devices, such as portable room-air cleaners and ultraviolet germicidal irradiation systems, has also been examined. Recently, the scope of the investigations has been widened. The most crucial issue is to minimise the potential for disease transmission and prevent the escape of contaminated air from the AIIR. Airflow direction inside the AIIR is also important and AIIRs minimise air leakage to save energy. On the other hand, it has been observed that efficient containment can be achieved even by using simple and inexpensive construction by considering pressure differential and air flow patterns. Nevertheless, additional research is needed to assist hospitals with improving their preparedness to cope with the threat of pandemics by building and using effective AIIRs.

Force Analysis of Double Pitch Point Cycloid Drive with Intermediate Rolling Elements and Free Retainer

2015 ◽  
Vol 756 ◽  
pp. 29-34
Author(s):  
E.A. Efremenkov ◽  
E.E. Kobza ◽  
S.K. Efremenkova
Keyword(s):  
Performance Improvement ◽  
Wedge Angle ◽  
Force Distribution ◽  
Force Analysis ◽  
Angle Variation ◽  
Rolling Elements ◽  
Further Development

This paper illustrates the analysis of wedge angle influence on force distribution in the meshing of double pitch point cycloid drive in comparison with single pitch point cycloid drive. Double pitch point cycloid drive may provide smoother performance of transmission at starting period in consequence of wedge angle variation capabilities. Matching initial parameters it is possible to modify the wedge angle and achieve its effective value. The influence of various combinations of initial parameters on the wedge angle and retainer force was studied and presented on diagrams. Some recommendations in designing related to performance improvement are given. The obtained results can be used for further development of better designs of cycloid drives.

A Neurofuzzy Knowledge Based Architecture for Robotic Hand Manipulation Forces Learning

2013 ◽  
Vol 3 (2) ◽  
pp. 16-38 ◽  
Author(s):  
Ebrahim Mattar
Keyword(s):  
Force Distribution ◽  
Robotic Hand ◽  
Knowledge Based ◽  
Optimal Force ◽  
Learning Technique ◽  
Optimization Formulation ◽  
Hand Grasp ◽  
Optimal Set ◽  
Dextrous Hand ◽  
Optimal Force Distribution

Optimal distribution of forces for manipulation by a robot hand, is a hard computational issue, specifically once a whole hand grasp is needed. It becomes a complicated issue, once a robotic hand is equipped with human like deformable sensory touching materials. For computing optimal set of manipulation forces, grip transform and inverse hand Jacobian play major roles for such purposes. This manuscript is discussing a Neurofuzzy learning technique for learning optimal force distribution by a dextrous hand. For learning purposes, optimal set of forces patterns were gathered in advanced using optimization formulation technique. After that, to let a Neurofuzzy system to learn the nonlinear kinematics-dynamics relations needed for force distribution. This is done by considering the computational requirements for the inverse hand Jacobian, in addition to the interaction between hand fingers and the object. Training patterns clustering, and generation of the fuzzy initial memberships, and updated shape of memberships, are considered as vital information to build upon for more reasoning of fuzzy interrelation. The technique is novel in a sense, that the adopted Neurofuzzy architecture was transparent in terms of revealing the learned hand optimal forces if then rules.

Experimental Study of Wave Force Distribution on a Monopile Structure

2018 ◽  
Author(s):  
Malene H. Vested ◽  
Stefan Carstensen ◽  
Erik Damgaard Christensen
Keyword(s):  
Experimental Studies ◽  
Cost Effective ◽  
Wave Force ◽  
Offshore Wind ◽  
Irregular Waves ◽  
Force Distribution ◽  
Wave Forces ◽  
Total Force ◽  
Wave Flume ◽  
Effective Manner

As the demand for offshore wind energy continues to grow, the strive to understand the wave forces acting on the substructure of the wind turbines continues. In regard to wind turbine design, it is vital to consider not only the total wave force, but also the local wave forces. Local forces are particularly important for the design of secondary structures as e.g. mooring platforms. Typically, however, experimental studies mainly concern total forces or idealized local forces. We present here a rather simple way to measure local forces along a model monopile. The study is conducted in a wave flume of 28 m in length, in which waves are generated by a piston-type wave maker at a water depth of 0.515 m and shoal onto a bed of slope 1:25. A model monopile is installed and subjected to forcing from a series of both regular and irregular waves. In the experimental set-up, the model monopile is fixed at the bottom and the top and consists of seven independent cylindrical sections. The cylindrical sections are connected by force transducers which measure local shear, and so the associated local forces may be determined. The measured local forces are compared to the force distribution given by Morisons equation combined with linear theory and Wheeler stretching, which is a force estimate commonly used in the industry. This study shows that the total force is rather well captured by Morison’s equation. The force distribution estimated from Morison’s equation, however, shows larger discrepancies from the measured forces. This encourages for further measurements. In this study, we show that it is possible to measure force distribution on a model monopile in a simple and cost-effective manner. The aim is here to demonstrate the method and we will later present a larger body of work associated with the outcome of the measurements.

Force Analysis of the Film in a COF Chip Mounter’s Loader

2004 ◽  
Author(s):  
Dein Shaw ◽  
H. C. Lin
Keyword(s):  
Friction Force ◽  
Relative Motion ◽  
Lower Layer ◽  
Axial Direction ◽  
Tension Force ◽  
Force Distribution ◽  
Force Analysis ◽  
Transportation Vehicle

In this study, the tension force distributions in the film of COF cartridge are studied. It is noted that if the tension force on the film is too high, the interface between chip and film cracked. If the force is too low, there is no enough friction force to keep the COF in fix position when the cartridge is on the transportation vehicle. The relative motion between the chips of lower layer and the film of upper layer will cause the fatigue of interface of chips and film. It is also important to note that due to the friction the tension force at any section of the film is different. To fine the force distribution, a method to determine the tension force is developed and only effect of axial direction is considered. The assumption makes the film behave like a string. The results show that the forces on the film are different whenever the film passes a chip underneath.

Analysis on the Instantaneous Stiffness of the 3-RPS Parallel Machine

2009 ◽  
Vol 407-408 ◽  
pp. 63-67 ◽  
Author(s):  
Xian Guo Han ◽  
Xue Liang Cui ◽  
Wu Yi Chen
Keyword(s):  
Jacobian Matrix ◽  
Screw Theory ◽  
Parallel Machine ◽  
Force Analysis ◽  
Stiffness Model ◽  
Generalized Force ◽  
Moving Platform ◽  
Position And Orientation

Based on the screw theory, the force analysis of the 3-RPS parallel machine is illuminated. Been equivalent to a 6-chain parallel machine, the deformation harmony equation of the parallel machine under the outside generalized force is interpreted. The instantaneous stiffness model of the parallel machine, which includes the change of the force Jacobian matrix, is established. Considering the deviation of the position and orientation of the moving platform, which is resulted from the distortion of the PRS chains of the parallel machine, the influence of the change of the Jacobian matrix to the instantaneous stiffness model of the 3-RPS parallel machine is analyzed, and furthermore, it is verified with an instance.

Friction-Induced Vibration in Lead Screw Systems: Mathematical Modeling and Experimental Studies

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
O. Vahid ◽  
N. Eslaminasab ◽  
M. F. Golnaraghi
Keyword(s):  
Experimental Studies ◽  
Lead Screw ◽  
Axial Forces ◽  
Angular Velocities ◽  
Regions Of Stability ◽  
Identification Approach ◽  
Simulation Results ◽  
The Mathematical Model ◽  
Steady State Amplitude ◽  
Friction Induced Vibration

Lead screw mechanisms are used to convert rotary to linear motion. The velocity-dependent coefficient of friction at the contact between lead screw and nut threads can lead to self-excited vibrations, which may result in excessive noise generated by the system. In this paper, based on a practical example of a powered automotive seat adjuster, the nonlinear dynamics of lead screw systems is studied. A test setup is developed to perform experiments on the horizontal motion drive. The experimental results are used in a novel two-step identification approach to estimate friction, damping, and stiffness parameters of the system. The identified parameters together with other known system parameters are used in the numerical simulations. The accuracy of the mathematical model is validated by comparing numerical simulation results with actual measurements in cases where limit cycles are developed. Using simulation results for a range of lead screw angular velocities and axial forces, regions of stability were found. Also, the effects of damping and stiffness parameters on the steady-state amplitude of vibration were investigated.

scholarly journals INTEGRATION OF IMAGE-DERIVED AND POS-DERIVED FEATURES FOR IMAGE BLUR DETECTION

2016 ◽  
Vol XLI-B1 ◽  
pp. 1051-1055 ◽  
Author(s):  
Tee-Ann Teo ◽  
Kai-Zhi Zhan
Keyword(s):  
Feature Extraction ◽  
Image Features ◽  
Motion Blur ◽  
Support Vector ◽  
Svm Classifier ◽  
Image Detection ◽  
Blur Detection ◽  
Angular Velocities ◽  
Image Blur ◽  
Position And Orientation

The image quality plays an important role for Unmanned Aerial Vehicle (UAV)’s applications. The small fixed wings UAV is suffering from the image blur due to the crosswind and the turbulence. Position and Orientation System (POS), which provides the position and orientation information, is installed onto an UAV to enable acquisition of UAV trajectory. It can be used to calculate the positional and angular velocities when the camera shutter is open. This study proposes a POS-assisted method to detect the blur image. The major steps include feature extraction, blur image detection and verification. In feature extraction, this study extracts different features from images and POS. The image-derived features include mean and standard deviation of image gradient. For POS-derived features, we modify the traditional degree-of-linear-blur (blinear) method to degree-of-motion-blur (bmotion) based on the collinear condition equations and POS parameters. Besides, POS parameters such as positional and angular velocities are also adopted as POS-derived features. In blur detection, this study uses Support Vector Machines (SVM) classifier and extracted features (i.e. image information, POS data, blinear and bmotion) to separate blur and sharp UAV images. The experiment utilizes SenseFly eBee UAV system. The number of image is 129. In blur image detection, we use the proposed degree-of-motion-blur and other image features to classify the blur image and sharp images. The classification result shows that the overall accuracy using image features is only 56%. The integration of image-derived and POS-derived features have improved the overall accuracy from 56% to 76% in blur detection. Besides, this study indicates that the performance of the proposed degree-of-motion-blur is better than the traditional degree-of-linear-blur.

scholarly journals FUZZY C-MEANS ALGORITHM FOR SEGMENTATION OF AERIAL PHOTOGRAPHY DATA OBTAINED USING UNMANNED AERIAL VEHICLE

2015 ◽  
Vol XL-5/W6 ◽  
pp. 113-115 ◽  
Author(s):  
M. V. Akinin ◽  
N. V. Akinina ◽  
A. Y. Klochkov ◽  
M. B. Nikiforov ◽  
A. V. Sokolova
Keyword(s):  
Unmanned Aerial Vehicles ◽  
Aerial Photography ◽  
Experimental Studies ◽  
Two Dimensional ◽  
Fuzzy C Means ◽  
Aerial Vehicles ◽  
Short Period ◽  
Aerial Vehicle ◽  
Fuzzy C Means Algorithm

The report reviewed the algorithm fuzzy c-means, performs image segmentation, give an estimate of the quality of his work on the criterion of Xie-Beni, contain the results of experimental studies of the algorithm in the context of solving the problem of drawing up detailed two-dimensional maps with the use of unmanned aerial vehicles. According to the results of the experiment concluded that the possibility of applying the algorithm in problems of decoding images obtained as a result of aerial photography. The considered algorithm can significantly break the original image into a plurality of segments (clusters) in a relatively short period of time, which is achieved by modification of the original k-means algorithm to work in a fuzzy task.

Sign in / Sign up

Export Citation Format

Share Document