scholarly journals Maneuverability Analysis of a Novel Portable Modular AUV

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Xiaoming Wang ◽  
Shengguo Liang
Keyword(s):  
Dynamic Performance ◽  
Vertical Plane ◽  
Maximum Velocity ◽  
Reference Value ◽  
Parameters Tuning ◽  
Turning Radius ◽  
Minimum Turning Radius ◽  
Differential Control ◽  
Thrust And Torque

ZFAUV is a novel portable modular AUV. There are four fixed thrusters at tail, and two tunnel thrusters are set at front. The maneuverability of ZFAUV is relatively high. It can turn around in situ, move lateral or move up/down vertical. The yaw and pitch can be controlled by tunnel thrusters or differential control of tail thrusters, but differential control will reduce the forward force. Different from propeller-rudder AUVs, the turning radius is related to speed forward: the smaller the speed forward, the smaller the turning radius. The minimum turning radius tends to be zero. The mathematical model is built first; then CFD is used to predict the thrust and torque of tail thrusters and tunnel thrusters. Through numerical simulation, zigzag maneuver analysis in horizontal plane, and trapezoidal steering maneuver analysis in vertical plane, the maneuverability of ZFAUV is obtained. The maneuverability of ZFAUV becomes worse with the increase of speed. The maneuverability of differential control is better than that of tunnel control. In the case of specific thrust distribution of tail thrusters and tunnel thrusters, ZFAUV can turn around in situ (the maximum angular velocity is about 24.1°/s), move lateral or move up/down vertical (the maximum velocity is about 0.4m/s). Finally, an example, PID parameters tuning, is given to illustrate the application of maneuverability analysis. The dynamic performance of ZFAUV can be quickly and accurately analyzed by mathematical method, which has important guiding significance for the choice of control strategy and experiments and also has reference value for the later development of AUVs.

Assessing Soil and Plant Pollution by Abandoned Rural Waste Dumping Sites in Ningbo, China

2011 ◽  
Vol 138-139 ◽  
pp. 1149-1155 ◽  
Author(s):  
Yi Dong Guan ◽  
Ye Hong Du ◽  
Zhen Dong Li ◽  
An Cheng Luo
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Reference Value ◽  
Dry Weight ◽  
Rice Grain ◽  
Contamination Assessment ◽  
Plant Parts ◽  
Metal Contents ◽  
Plant Pollution

This paper reports the concentration of heavy metals (Cr, Cu, Zn, Cd and Pb) in the soils and rices surrounding the abandoned rural waste dumping sites in Ningbo. Igeo (geoaccumulation index) was calculated to assess the contamination degree of heavy metals in soils. The mean contents of Cr, Cu, Cd, Zn and Pb of soils were 33.3, 24.1, 1.5, 118.9 and 45.6 mg/(kg DW) (dry weight), respectively. All of them were much higher than that of the reference value (i.e. CK), but there were no coherent trend of the metal contents within 1-120m distance from the dumping site. Igeo of heavy metals reveals the order of Cd>Cu>Cr>Pb>Zn, and the contamination assessment of soils using Igeo indicate the moderate Cd pollution, while the soils were unpolluted-moderately overall by Cr, Cu, Zn as well as Pb. The heavy metal contents in root, stem & leaf and rice grains were all remarkable higher than that of the CK at 20-120 m distances, and the heavy metal contents in root were evidently much higher than other plant parts, while those in rice grain were lowest, indicating the great bioaccumulation trend of heavy metals. Although the metal contents in the rice grain were within the legislation limit, its bioaccumulation trend of heavy metals was remarkable, whose contents were 4.38-fold for Cr, 1.76-fold for Cu, 1.28-fold for Zn, 2.67-fold for Cd and 3.03-fold for Pb higher than that of reference value, respectively. Finally, we proposed a decentralized in-situ restoration approach for the dumping sites.

scholarly journals A device for testing the dynamic performance of in situ force plates

2017 ◽  
Vol 231 (9) ◽  
pp. 923-927
Author(s):  
Rebecca H East ◽  
Jonathan J Noble ◽  
Richard A Arscott ◽  
Adam P Shortland
Keyword(s):  
Dynamic Performance ◽  
In Situ Force

scholarly journals Surface Fitting for non-Grid Data from in-Situ Measuring Systems of Aero-engine Blade

2020 ◽  
Vol 206 ◽  
pp. 03023
Author(s):  
Qing Mao ◽  
Sen Wang ◽  
Shugui Liu
Keyword(s):  
Dynamic Performance ◽  
Surface Fitting ◽  
Data Conversion ◽  
Machining Accuracy ◽  
Nurbs Surface ◽  
Grid Data ◽  
Measuring Systems ◽  
Aero Engine ◽  
Engine Blade

High machining accuracy of aero-engine blade largely determines the carrying capacity, endurance, acceleration and the dynamic performance of the aero-engine, so a reliable machining error inspection and evaluation technique is imperative. In order to give a reliable error evaluation, the non- uniform rational B-spline (NURBS) technique is adopted to reconstruct the surface within a specified accuracy. Usually, data points measured from aero-engine blade are non-grid data in situ measuring systems. To overcome the difficulty of NURBS surface fitting from non-grid data, a new method based on data conversion is proposed, in which chord length parameterization and uniform parameter sampling are combined together to realize the data convertation, and subsequently hierarchical fitting strategy is applied to finish the NURBS surface reconstruction. The way proposed for data conversion is easy to realize, and by which gemetrical features of original measured data are also reserved well, which make the whole method outstanding in low time cost. Experimental results show that the method is fast, effective. The source code has been implemented in VC++, while the resulting pictures are constructed in Matlab with the obtained control points, knot vectors, and the orders.

A Multi-Purpose Off-Line Path Planner Based on an A* Search Algorithm

1996 ◽  
Author(s):  
Arturo L. Rankin ◽  
Carl D. Crane
Keyword(s):  
Search Algorithm ◽  
Piecewise Linear ◽  
Autonomous Mobile Robot ◽  
Linear Path ◽  
Shortest Distance ◽  
Computer Controlled ◽  
Turning Radius ◽  
Minimum Turning Radius ◽  
Path Planner ◽  
Line Path

Abstract Efficient navigation of an autonomous mobile robot through a well-defined environment requires the ability of the robot to plan paths. An efficient and reliable planar off-line path planner has been developed that is based on the A* search method. Using this method, two types of planning are accomplished. The first uses a map of all known obstacles to determine the shortest-distance path from a start to goal configuration. The second determines the shortest path along a network of predefined roads. For the most complicated environment of obstacles and roads, a near-optimal piecewise-linear path is found within a few seconds. The planner can generate paths for robots capable of rotation about a point as well as car-like robots that have a minimum turning radius. For car-like robots, the planner can generate forward and reverse paths. This software is currently implemented on a computer controlled Kawasaki Mule 500 all-terrain vehicle and a computer controlled John Deere 690 excavator.

scholarly journals Parametric Optimization Design of Auto-unloading Mechanism Based on Adams

2018 ◽  
Vol 175 ◽  
pp. 03052
Author(s):  
Yongliang Yuan
Keyword(s):  
Optimization Design ◽  
Parametric Optimization ◽  
Optimal Parameter ◽  
Dynamic Performance ◽  
Reference Value ◽  
Lifting Force ◽  
Parameter Combination ◽  
Simulation Results ◽  
Mechanical Devices ◽  
Relationship Of

In order to improve the dynamic performance of a truck dump mechanism, the optimal parameter combination of the dump mechanism is studied. In combination with Adams' own modeling work, the dump mechanism is simplified and modeled and simulated. The objective function is optimized with the minimum lifting force, and the parameter combination of the best position relationship of the dump mechanism is obtained. The simulation results show that Adams can accurately predict the optimal parameter combination of mechanical devices, which have certain reference value for engineering design.

Size-dependent behavior of laminates with curvilinear fibers made by automated fiber placement

2015 ◽  
Vol 22 (2) ◽  
pp. 157-163 ◽  
Author(s):  
Mahdi Arian Nik ◽  
Larry Lessard ◽  
Damiano Pasini
Keyword(s):  
Variable Stiffness ◽  
Buckling Load ◽  
Fiber Placement ◽  
Plate Size ◽  
Load Increase ◽  
Automated Fiber Placement ◽  
Fiber Path ◽  
Turning Radius ◽  
Curvilinear Fibers ◽  
Minimum Turning Radius

AbstractVariable stiffness laminates can be manufactured using curvilinear fiber paths. A curvilinear fiber path is generally defined based on the plate size and has a curvature that is dependent on the plate size. In practice, however, the fiber path must satisfy manufacturing constraints, such as the minimum turning radius imposed by the automated fiber placement machine, thereby limiting the possible amount of fiber steering. In this work, we studied the effect of the plate size on the structural properties of a plate manufactured with curvilinear fibers. We considered four plate sizes, which were designed by a constant curvature fiber path. We optimized the plates for both maximum buckling load and in-plane stiffness. The results showed that the in-plane stiffness of the plate was not controlled by the plate size, whereas the buckling load was highly affected by the curvature of the fiber path. Hence, the potential of a buckling load increase reduced for plate sizes smaller than the minimum turning radius. In addition, for a given maximum curvature of the fiber path, the influence of a complex layup on the buckling load was marginal.

Main Parameters Calculation and Performance Test of 7YGS-45 Type Self-Propelled Dual-Track Orchard Transport

2012 ◽  
Vol 499 ◽  
pp. 232-237
Author(s):  
Jun Jun Xing ◽  
Shan Jun Li ◽  
Yan Lin Zhang
Keyword(s):  
Power Consumption ◽  
Performance Test ◽  
Slope Angle ◽  
Operation Performance ◽  
Running Speed ◽  
Turning Radius ◽  
And Performance ◽  
Minimum Turning Radius ◽  
Parameters Calculation

Targeting mountain orchards, which slope from 25 degrees to 45 degrees, the 7YGS-45 type self-propelled dual-track orchard transport was developed. Through designing，optimize the following key parameters such as power consumption、running speed、turning radius and slope angle, and have real operation performance test for dual-track orchard transport. The test shows that the transport’s maximum climbing slope is 47°, minimum turning radius is 8m, and it can satisfy the steady running with the speed of 1.1m/s-1.3m/s and capacity of 300kg. The 7YGS-45 type self-propelled dual-track orchard transport is not only suitable for transporting the fruits and fertilizers in mountain orchards, but also can be equipped with spraying and pruning machines to work.

scholarly journals An Autonomous Open-Ocean Stereoscopic PIV Profiler

2010 ◽  
Vol 27 (8) ◽  
pp. 1362-1380 ◽  
Author(s):  
Jonah V. Steinbuck ◽  
Paul L. D. Roberts ◽  
Cary D. Troy ◽  
Alexander R. Horner-Devine ◽  
Fernando Simonet ◽  
...  
Keyword(s):  
Flow Direction ◽  
Vertical Plane ◽  
Free Fall ◽  
Open Ocean ◽  
Stereoscopic Particle Image Velocimetry ◽  
Frame Rate ◽  
Energy Estimates ◽  
Seeding Density ◽  
Stereoscopic Piv

Abstract Over the past decade, a novel free-fall imaging profiler has been under development at the Scripps Institution of Oceanography to observe and quantify biological and physical structure in the upper 100 m of the ocean. The profiler provided the first detailed view of microscale phytoplankton distributions using in situ planar laser-induced fluorescence. The present study examines a recent incarnation of the profiler that features microscale turbulent flow measurement capabilities using stereoscopic particle image velocimetry (PIV). As the profiler descends through the water column, a vertical sheet of laser light illuminates natural particles below the profiler. Two sensitive charge-coupled device (CCD) cameras image a 25 cm × 25 cm × 0.6 cm region at a nominal frame rate of 8 Hz. The stereoscopic camera configuration allows all three components of velocity to be measured in the vertical plane with an average spatial resolution of approximately 3 mm. The performance of the PIV system is evaluated for deployments offshore of the southern California coast. The in situ image characteristics, including natural particle seeding density and imaged particle size, are found to be suitable for PIV. Ensemble-averaged velocity and dissipation of turbulent kinetic energy estimates from the stereoscopic PIV system are consistent with observations from an acoustic Doppler velocimeter and acoustic Doppler current profiler, though it is revealed that the present instrument configuration influences the observed flow field. The salient challenges in adapting stereoscopic PIV for in situ, open-ocean turbulence measurements are identified, including cross-plane particle motion, instrument intrusiveness, and measurement uncertainty limitations. These challenges are discussed and recommendations are provided for future development: improved alignment with the dominant flow direction, mitigation of instrument intrusiveness, and improvements in illumination and imaging resolution.

The Turning Radius Analysis for Pneumatic Beam Transport Trailer of Principal and Subordinated Vehicle Model with Combination of Four-Wheel Steering and Articulated Frame

2012 ◽  
Vol 253-255 ◽  
pp. 2181-2187
Author(s):  
Zhen Jun Sun ◽  
Xiao Fei Yan ◽  
Li Jun Han
Keyword(s):  
Calculation Formula ◽  
Beam Transport ◽  
Vehicle Model ◽  
Turning Radius ◽  
Minimum Turning Radius

This paper put forward a struction model of pneumatic beam transport trailer of principal and subordinated vehicle model with combination of four-wheel steering and articulated frame. Its steering conditions are analyzed. The steering condition and the method of determining of the minimum turning radius and the calculation formula of turning radius are obtained.

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