Position Registration of Scanning Lasers for Experimental Spatial Dynamics Modeling

1994 ◽  
Author(s):  
David E. Montgomery ◽  
Robert L. West
Keyword(s):  
Spatial Dynamics ◽  
Spatial Models ◽  
Laser Doppler Vibrometer ◽  
Sample Surface ◽  
Surface Shape ◽  
Surface Velocity ◽  
Multiple Point ◽  
Range Data ◽  
Dynamics Modeling ◽  
Velocity Measurements

Abstract Experimental spatial dynamics modeling involves using scanning lasers to sample surface shape and dynamic response of structures in order to verify structural dynamics design intent. Formation of accurate spatial models from laser-based measurements requires that laser position and orientation be registered relative to a fixed coordinate system. A three point direct registration procedure is defined for shape modeling using laser range and mirror deflection angles. Surface velocity measurements with a portable laser Doppler vibrometer (LDV) also require registration, but range information is unavailable. A multiple point indirect registration algorithm for the LDV is described that involves minimizing three nonlinear equations. A simulated laser rangefinder (LRF) was developed for demonstrating three point direct registration. The 3-D geometry of a compressor housing was modeled by combining range data from multiple laser positions. The multiple point indirect registration was applied to 3-D velocity response field reconstruction of a composite plate from velocity measurements scanned at three separate positions.

Dynamics modeling and analysis of a four-wheel independent motor-drive virtual-track train

2020 ◽  
pp. 146441932096401
Author(s):  
Zhonghui Yin ◽  
Jiye Zhang ◽  
Haiying Lu ◽  
Weihua Zhang
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Spatial Dynamics ◽  
Dynamic Responses ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Coupling Effects ◽  
Dynamic Interactions ◽  
Modeling And Analysis

Due to urbanisation and the economic challenges of traffic, it is urgently necessary to develop an environmentally friendly virtual-track train with suitable speed, high load capacity and low construction cost in China. To guide the design and evaluate this train’s dynamic behaviour, a spatial-dynamics model has been developed based on the dynamics theory and tyre-road interaction. The proposed dynamics model comprises mechanical vehicle systems, traction and braking characteristics and tyre-road dynamic interactions. The coupling effects amongst those systems of virtual track train are derived theoretically for the first time. The nonlinear characteristics of the tyre are modelled by the transit tyre-magic formula with consideration of road irregularities. Based on a designed PID controller and the comprehensive dynamics model, the dynamic performance of the system can be revealed considering motion coupling effects and complicated excitations, especially under traction and braking conditions. The dynamic responses of whole virtual track train can be obtained by numerical integration under different conditions. The vibration characteristics of such train are assessed under running at a constant speed and during the traction/braking process. The results show that the vibrations of the vehicle system are significantly influenced by road irregularities, especially at high speed ranges. The motions and vibrations of different components are intensive coupled, which should not to be neglected in the dynamics assessment of the virtual track train. Besides, the dynamics model can also be applied to dynamics-related assessment (fatigue, strength and some damage conditions, et al.) and parameter optimisation of the virtual-track train.

Advancing the application of the ideal free distribution to spatial models of fishing effort: the isodar approach

2012 ◽  
Vol 69 (10) ◽  
pp. 1610-1620 ◽  
Author(s):  
D.M. Gillis ◽  
A. van der Lee
Keyword(s):  
Behavioral Ecology ◽  
Interference Competition ◽  
Ideal Free Distribution ◽  
Spatial Dynamics ◽  
Spatial Models ◽  
Fishing Effort ◽  
Model Parameters ◽  
Free Distribution ◽  
Ideal Free ◽  
The Ideal

The ideal free distribution (IFD) of behavioral ecology has been used in the study of the distribution of fishing effort since the 1990s. Concurrently, evolutionary perspectives on forager distributions have led to the development of theoretical curves of equal fitness, named isodars, to test IFD hypotheses. We develop isodars, based upon catch rates and unknown costs, to quantify regularity in the distribution of fishing effort among alternative areas. Our analyses indicate that these isodars provide significantly better predictions than a simple IFD without costs. Autocorrelation in the catch and effort data necessitates the use of generalized linear least squares when estimating model parameters. Differences in costs that are proportional to effort are more clearly identified in the model than nonlinear effects, which may arise from extreme interference competition. The isodar approach provides a new tool for examining the spatial dynamics of catch and effort data. It improves the accuracy of predictions and provides new parameters related to costs and vessel interactions that can be applied to rapidly identify situations where effort dynamics have changed.

Terrain analyses and surface velocity measurements of the Hiorthfjellet rock glacier, Svalbard

2003 ◽  
Vol 14 (4) ◽  
pp. 359-365 ◽  
Author(s):  
Rune S. Ødegård ◽  
Ketil Isaksen ◽  
Trond Eiken ◽  
Johan Ludvig Sollid
Keyword(s):  
Surface Velocity ◽  
Velocity Measurements ◽  
Rock Glacier

Simultaneous multiple-point velocity measurements using laser-induced iodine fluorescence

1983 ◽  
Vol 8 (1) ◽  
pp. 51 ◽  
Author(s):  
J. C. McDaniel ◽  
B. Hiller ◽  
R. K. Hanson
Keyword(s):  
Multiple Point ◽  
Velocity Measurements ◽  
Point Velocity

scholarly journals Measurement of Surface Strain-Rate on Taku Glacier, Alaska

1964 ◽  
Vol 5 (39) ◽  
pp. 305-313 ◽  
Author(s):  
T. H. Wu ◽  
R. W. Christensen
Keyword(s):  
Strain Rate ◽  
Reasonable Agreement ◽  
Stress Condition ◽  
Surface Strain ◽  
Surface Velocity ◽  
Strain Rates ◽  
Velocity Measurements ◽  
Measured Velocity ◽  
Valley Glacier ◽  
Measured Strain

AbstractStrain-rate and surface velocity measurements were made on a valley glacier. The measured strain-rates were used to calculate the stress condition and velocity distribution in the glacier. The measured velocity is in reasonable agreement with that calculated from Nye’s plasticity solution.

Surface velocity and mass balance of Ice Streams D and E, West Antarctica

1996 ◽  
Vol 42 (142) ◽  
pp. 461-475 ◽  
Author(s):  
Robert Bindschadler ◽  
Patricia Vornberger ◽  
Donald Blankenship ◽  
Ted Scambos ◽  
Robert Jacobel
Keyword(s):  
Mass Balance ◽  
Surface Velocity ◽  
Random Errors ◽  
West Antarctica ◽  
Velocity Measurements ◽  
Ice Streams ◽  
Ice Stream ◽  
Data Density ◽  
Basal Shear ◽  
Collection Methods

AbstractOver 75 000 surface-velocity measurements are extracted from sequential satellite imagery of Ice Streams D and E to reveal a complex pattern of flow not apparent from previous measurements. Horizontal and vertical strain rates, calculated from surface velocity, indicate that the bed experiences larger basal shear where the surface of these ice streams is rougher. Ten airborne-radar profiles and one surface-based radar profile of ice thickness make possible the calculation of mass balance for longitudinal sections of each ice stream. Improved data-collection methods increase data density, substantially reducing random errors in velocity. However, systematic errors continue to limit the ability of the flux-differencing technique used here to resolve local variations in mass balance. Nevertheless, significant local variations in mass balance are revealed, while, overall, Ice Streams D and E are in approximate equilibrium. An earlier estimate of the net mass balance for Ice Stream D is improved.

scholarly journals Learning part-based spatial models for laser-vision-based room categorization

2017 ◽  
Vol 36 (4) ◽  
pp. 379-402 ◽  
Author(s):  
Peter Uršič ◽  
Aleš Leonardis ◽  
Danijel Skočaj ◽  
Matej Kristan
Keyword(s):  
Spatial Model ◽  
Spatial Models ◽  
Range Data ◽  
Large Dataset ◽  
New Approach ◽  
Laser Range ◽  
Learning Technique ◽  
Laser Vision ◽  
Domestic Environments ◽  
Discriminative Dictionary Learning

Room categorization, that is, recognizing the functionality of a never before seen room, is a crucial capability for a household mobile robot. We present a new approach for room categorization that is based on two-dimensional laser range data. The method is based on a novel spatial model consisting of mid-level parts that are built on top of a low-level part-based representation. The approach is then fused with a vision-based method for room categorization, which is also based on a spatial model consisting of mid-level visual parts. In addition, we propose a new discriminative dictionary learning technique that is applied for part-dictionary selection in both laser-based and vision-based modalities. Finally, we present a comparative analysis between laser-based, vision-based, and laser-vision-fusion-based approaches in a uniform part-based framework, which is evaluated on a large dataset with several categories of rooms from domestic environments.

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