Towed Vehicle Research Articles

Deep-tow 3C magnetic measurement: Solutions for calibration and interpretation

Two main problems are encountered in deep-tow 3C magnetic surveys. The first problem is related to instrumental error due to the manufacturing of the sensor, its integration in the towed fish structure, and the magnetization of the vehicle carrying the magnetometer; the second is related to the variation in altitude of the instruments during the dive. We evaluated a new type of calibration approach for deep-tow fluxgate magnetometers. We found that the magnetometer can be calibrated with no recourse to the vehicle attitude (pitch, roll, and heading, as it is usually achieved) but only using the three components recorded by the magnetometer and an approximation of the scalar intensity of the earth’s magnetic field. This method, called scalar calibration, allowed us to eliminate the intrinsic instrumental errors as well as the magnetization effect of the tow vehicle. Thus, despite the low maneuverability of the towed fish during the calibration experiment, we discovered a significant improvement in obtaining accurate magnetic anomaly profiles. Because only the total field anomaly and not the magnetic vector is suitable for this method, we investigated the possibility of calculating the three components via an equivalent-source approach. Therefore, assuming a 2D topographic equivalent layer, we found a stable and a meaningful magnetization of the oceanic crust. We discovered that although magnetic data are acquired along uneven tracks, this model, based on a single linear inversion, is sufficient to provide a first-order depth and magnetization intensity of the crust and also to carry out upward continuation of the total anomalous field as well as its associated vector.

Development of the on-board control-signal system for determination of changes of accelerations of vehicles

The article is dedicated to the study of the changes of vibrations of sprung and non-sprung masses of wheeled towing vehicles when driving on ground supporting surfaces with low bearing capacity. The article presents the description of the developed on-board control-signal system, designed to trace the changes of current values of the longitudinal, lateral and vertical accelerations of sprung and non-sprung masses of towing vehicles. The developed on-board control-signal system provides the control of accelerations, primarily vertical, as they have greater effect on the vibrations, causing the increase of the dynamic loads on the elements of drive systems, and ultimately the increase of pressure of propellers on a supporting surface. To check the action of the created onboard control-signal system we have carried out road tests on the wheeled towing vehicle, resulting in obtaining of the experimental data of the change of longitudinal, lateral and vertical accelerations; and the values varied over a wide range and reached 4 m/s 2 (vertical accelerations). This work can provide a reduction of dynamic loads in the drive system of the wheeled towing vehicles, improve the ride and reduce the pressure of propellers on the deformable supporting surface (soil).

Towed transient electromagnetic survey for groundwater investigation - challenges and solutions.

SUMMARY Towed transient electromagnetic survey (TEM) is conducted by towing loops of wire behind a vehicle, one transmitting and several receiving. The loop sizes must be large enough to transmit/receive moments well in excess of EM noise levels while loop inductances must be kept low in order to keep turn-off time and system response low enough to resolve shallow detail. Long systems with the towing vehicle well in front of two separate nonmetallic loop support structures are practical. As such a system must fit through farm gates, between trees, and along road margins without undue traffic disruption, it must be capable of folding to legal road vehicle width. Processing involves most of the normal complications of airborne EM survey but with the additional complication that the system cannot be elevated high above the ground to isolate system response. Additional challenges are identification and removal/minimization of noise and metallic source anomalies: 1. created by movement of coils through the magnetic field of the earth, 2. created by buried telephony cables, and 3. from other sources such as power lines, buried metal pipes and fences. Much of Australia is reasonably navigable and not densely covered with infrastructure and it is in these parts of Australia where towed TEM systems, which can be deployed and manoeuvred flexibly, have a market for groundwater and other exploration.

Oceanographic Field Estimates from Remote Sensing and Glider Fleets

Abstract This work investigates the merging of temperature observations from a glider fleet and remote sensing, based on a field experiment conducted in an extended coastal region offshore La Spezia, Italy, in August 2010. Functional optimal interpolation and spline formalisms are used to integrate temperature profiles from a fleet of three gliders with remotely sensed sea surface temperature into a volumetric thermal field estimate. Independent measurements from a towed ScanFish vehicle are used for validation. Results indicate that the optimal interpolation approach performs better than the spline model at and above the thermocline depth as long as anisotropic covariances computed from the remote sensing data are used. Below the thermocline, the two merging techniques give similar performance.

The Influence of Double Acting Hydraulic Piston on Tractive Forces for Towing Vehicle on Steering of Wagon Type Articulated Tracked Vehicle(English)

Tracked vehicles have been in use for many years ago thus, there has been increasing interest in articulated tracked vehicles for various applications such as they can be used as transporters for heavy equipment or as heavy earth-moving machines. Generally, it has been accepted that the wagon-type articulation of tracked vehicles is the simplest type of articulation. However, previous analysis has shown that this kind of articulation createsa problem to steering in the straightening-up position. This paper deals theoretically withthe possibility of changing the hydraulic piston, which used now in articulated tracked vehicles by a double acting hydraulic piston as another solution.It explains the effect of two forces of the piston on the outside tractive force and inside tractive force for the towing vehicle, when using a conventional wagon-type articulation of tracked vehicles with the introduction of double acting hydraulic piston in the system.It show that the length to the width ratio of the towing tracked vehicle is the main factor that affects much more than the other on the forces of the towing vehicle, where the value of this ratio (less than one) gives a good straighting up. Keywords: tracked vehicles, articulation of tracked vehicles, thrust force, hydraulic piston

Just-in-Time supermarkets for part supply in the automobile industry

In the automotive industry, a supermarket is a decentralized in-house logistics area for intermediately storing parts in direct vicinity of the assembly line consuming these parts. In a supermarket, tow trains—consisting of a small towing vehicle and a few waggons—are loaded with parts, which then successively visit the stations of the line according to a periodical schedule exchanging empty with filled part bins. This emerging logistics concept enables a reliable and flexible small-lot delivery of parts in line with the basic Just-in-Time (JIT) philosophy. This paper describes the supermarket concept in detail and surveys the literature on the elementary decision problems arising when implementing the supermarket concept. Finally, interfaces with other basic business functions are characterized.

Sway Stability of 5TH Wheel RV Trailers

This paper presents trailer sway testing results of a 5th wheel RV toy-hauler being towed by a conventional dually pick-up. Tests were performed at various speeds, trailer gross weights, king pin weights, and tire pressures. Results validate the understanding that 5th wheel trailers, at 20% pin weight generally have substantially better sway damping than conventional trailers. Tests at 10% pin weight show trailer sway damping is substantially reduced, but still is well above minimum industry accepted standards. Much of the improved sway damping for 5th wheel trailers can be attributed to the forward hitch location and not just the higher hitch loads that are typically used. What this means is that, although the recommended hitch load for a fifth wheel trailer is typically 20% or more, the sway response of the combination may be acceptable with substantially lower hitch loads, and they may maintain acceptable stability when the tow vehicle to trailer weight ratio is substantially less than 1:1, which does not generally occur with conventional travel trailers. Language: en

Modeling and Simulation on Fluid Dynamic Depth-Setting TUV Based on FLUENT

The prerequisite factors for the simulation and controlling of underwater vehicles are hydrodynamic coefficients, which we must measure accurately. In this paper, we took a complex shape remotely operated vehicle as the test model, and figured out the important coefficients that can be applicable for the open-shelf depth-setting TUV through a series of hydrodynamic tests. In order to boost the reliability of a depth-setting TUV system, we carry out numerical simulation and hydrodynamics method on the body of the TUV through the Dynamic Analysis of a single rudder .Comparing with empirical equation, the method has be predicted a high accuracy in hydrodynamic characteristic prediction of depth-setting towed vehicle . After changing the experiment environment of the TUV as possible as we can, a suitability algorithm can be used on the distribute system. And then, the pre-design and later validation of TUV with the conclusion of the simulation based on FLUENT which contribute to shorter calculating period and lower economy could show better depth-setting consequent. The paper draw the Process of the Dynamic Depth-setting TUV for three parts including simulation of the rubber , algorithm experiment of the body and the experiment on TUV.

Safe operation of an autonomous underwater towed vehicle: Towed force monitoring and control

On underwater towed systems, the towing cable plays an important role in transmitting electric signals and towing forces. Hence, it is strongly recommended to monitor the towed force for preventing cable breaks and making use of it more efficiently; however, most existing underwater towed systems do not have such a capability. This paper discusses towed force monitoring and control for safe operation of an autonomous towed vehicle that is a kind of autonomous underwater vehicle (AUV). We first overview the autonomous towed vehicle and describe our related previous works. We then present our towed force measuring and monitoring manners and an experimental methodology for obtaining the feasible range of the towed force. In addition, towed force estimation only with vehicle dynamics is presented for the case when the towed force sensor became useless. Finally, we discuss towed force control to keep the towed force inside its feasible region.

Ocean color patterns help to predict depth of optical layers in stratified coastal waters

Subsurface optical layers distributed at two different depths were investigated in Monterrey Bay, East Sound, and the Black Sea based on spatial statistics of remote sensing reflectance (Rrs). The main objective of this study was to evaluate the use of Rrs(443)/Rrs(490) (hereafter R1) skewness (ψ) as an indicator of vertical optical structure in different marine regions. Measurements of inherent optical properties were obtained using a remotely op- erated towed vehicle and R1 was theoretically derived from optical profiles. Although the broad range of trophic status and water stratification, a common statistical pattern consist- ing of lower ψR1—a deeper optical layer was found in all study cases. This variation was attributed to optical changes above the opticline and related to horizontal variability of par- ticulates and spectral variations with depth. We recommend more comparisons in stratified coastal waters with different phytoplankton communities before the use of ψR1 can be gener- alized as a noninvasive optical proxy for screening depth changes on subsurface optical layers.

Nonlinear adaptive control of an underwater towed vehicle

This paper addresses the problem of simultaneous depth tracking and attitude control of an underwater towed vehicle. The system proposed uses a two-stage towing arrangement that includes a long primary cable, a gravitic depressor, and a secondary cable. The towfish motion induced by wave driven disturbances in both the vertical and horizontal planes is described using an empirical model of the depressor motion and a spring-damper model of the secondary cable. A nonlinear, Lyapunov-based, adaptive output feedback control law is designed and shown to regulate pitch, yaw, and depth tracking errors to zero. The controller is designed to operate in the presence of plant parameter uncertainty. When subjected to bounded external disturbances, the tracking errors converge to a neighbourhood of the origin that can be made arbitrarily small. In the implementation proposed, a nonlinear observer is used to estimate the linear velocities used by the controller thus dispensing with the need for costly sensor suites. The results obtained with computer simulations show that the controlled system exhibits good performance about different operating conditions when subjected to sea-wave driven disturbances and in the presence of sensor noise. The system holds promise for application in oceanographic missions that require depth tracking or bottom-following combined with precise vehicle attitude control.

An experimental and computational study of the aerodynamic and passive ventilation characteristics of small livestock trailers

This paper presents a combined experimental and computational study of the aerodynamics and passive ventilation characteristics of small livestock trailers within which the majority of animals in the United Kingdom are transported to market. Data obtained from a series of wind tunnel experiments using a 1/7th scale model of a simplified towing vehicle and trailer are compared with complementary computational fluid dynamics (CFD) analyses, based on steady-state RANS turbulence modelling, of the coupled external/internal flow field. Good agreement between the two is obtained everywhere except at the rear of the trailer. Since the internal flow field and overall ventilation rates contribute to animal welfare, CFD is used to generate detailed internal flow fields and air residence times for use within an overall welfare assessment. The results demonstrate that the flow fields in the upper and lower decks differ significantly and that ventilation rates are much larger and air residence times much smaller on the upper deck.

Associations of lobsters (Homarus americanus) off southwestern Nova Scotia with bottom type from images and geophysical maps

Abstract Tremblay, M. J., Smith, S. J., Todd, B. J., Clement, P. M., and McKeown, D. L. 2009. Associations of lobsters (Homarus americanus) off southwestern Nova Scotia with bottom type from images and geophysical maps. – ICES Journal of Marine Science, 66: 2060–2067. Images from an underwater towed vehicle (Towcam) were used to estimate densities and to evaluate bottom-type associations of lobsters (Homarus americanus), crabs (Cancer spp.), and scallops (Placopecten magellanicus). Images were obtained in October 2006 along 14 line-transects off southwestern Nova Scotia in an area with productive lobster and scallop fisheries. Lobsters were observed in 4% of the 2044 images, crabs in 7%, and scallops in 40%. On sand, gravel, and cobble seabed, lobsters were readily observable. On rougher substrata with boulders, some lobsters were still evident either in the open or partially hidden in shelters. Estimated densities of lobsters from the images on some transects were 0.04 m−2, approximately half of the estimates of lobster density for adjacent inshore areas from scuba, but 34 times higher than estimates from scallop drags in the same area. Models of animal presence by bottom type were evaluated with categories that were (i) geophysically based (map of bottom type from geophysical characteristics) and (ii) image-based (sediment size from images). Significant relationships were evident with both types of seabed categorization, suggesting that it would be beneficial to stratify surveys using geophysical categories. Depth was also significant in determining presence/absence of lobsters and crabs. There is potential to develop indicators of lobster abundance using underwater imaging, and stratification by bottom type should be incorporated into surveys.

G1501-3-1 可動翼付水中曳航体の運動解析(作業ロボット・その他)

A designed problem for wings of the towed vehicle, which surveys the bottom of seabed in large depth, is considered. In order to survey seabed using the sonar equipped on the towed vehicle, the vehicle is required to cruse with the same depth or the same altitude from seabed and reduce a noise as much as possible. From these points of view, the variable wing, i.e. various type of wings for the vehicle can be replaced depending upon the operating speed, situation etc, is considered as one of effective methods. In this paper, to develop such towed vehicle, the effect of the angle between the body and wing, the wing form and the wing size of the towed vehicle are analyzed.

Nonlinear adaptive depth tracking and attitude control of an underwater towed vehicle

This paper addresses the problem of simultaneous depth tracking and precise attitude control of an underwater towed vehicle integrated in a two-stage towing arrangement. A nonlinear Lyapunov-based output feedback controller is designed to operate in the presence of plant parameter uncertainty and proven to regulate pitch, yaw, and depth tracking errors to zero. When subjected to bounded external disturbances, the tracking errors converge to a neighborhood of the origin that can be made arbitrarily small. In the implementation proposed, a nonlinear observer is used to estimate the linear velocities used by the controller. The results obtained with computer simulations including sea wave driven disturbances and sensor noise, show that the controlled system exhibits good performance about different operating conditions and holds considerable potential for oceanographic missions that require simultaneous depth and attitude control.

Trailer truck-mounted attenuator

A new trailer truck-mounted attenuator protection system was designed and successfully crash tested according to the safety performance criteria presented in NCHRP Report 350. The new trailer is designed to be attached to a tow vehicle using a conventional pintle hitch and wiring harness. This simple attachment will allow the new trailer to be attached directly to many work trucks, such as striping vehicles to eliminate the need for secondary shadow vehicles. The trailer is manufactured from heavy gage, galvanized steel to provide the first practical solution to protecting motorists during snow plowing, sanding and salting operations. Five full-scale crash tests were successfully conducted with the trailer attached to a tow vehicle that was blocked against forward movement and rotation to simulate an infinitely heavy vehicle.

Forensic Engineering Analysis Of Trailer Sway Accidents

This Paper Describes A Method For The Reduction Of System Response Data For Second Order Electrical Or Mechanical Systems When That Data Is Available Only In Graphical Format. The Method Of Data Reduction Described Allows Quantitative Evaluation Of Generally Accepted Second Order System Parameters Such As: System Time Constant, Damped Natural Frequency, Damping Ratio, And Exponential Decay Time. The Discussion Includes The Application Of The Described Graphical Technique To Experimental System Response Data Of Coupled Systems, But Whose Experimental Response Approximates That Of An Isolated Second Order System. A Practical Application Of The Described Data Reduction Method Is Covered In Detail. The Described Technique Is Applied To The Analysis Of Data Obtained Experimentally For The Response Of A Tow Vehicle And Trailer System To A Standardized Steering Disturbance. Finally, The Statistical Validation For Experimental System Response Data And The Results Obtained From The Analysis Of Such Data, Using The Described Graphical Method, Is Discussed.

Regulated emissions from biodiesel fuels from on/off-road applications

This research is one of the largest studies of biodiesel in both on-road and off-road uses. The testing was conducted for the military and encompassed a wide range of application types including two medium-duty trucks, two Humvees, a heavy heavy-duty diesel truck, a bus, two stationary backup generators (BUGs), a forklift, and an airport tow vehicle. The full range of fuels tested included a California ultra-low sulfur diesel (ULSD) fuel, different blend ratios of two different yellow-grease biodiesels and one soy-based biodiesel, JP-8, and yellow-grease biodiesel blends with two different NO x reduction additives. The B20-YGA, B20-YGB, and B20-Soy did not show trends relative to ULSD that were consistent over all applications tested. Higher biodiesel blends were tested on only one vehicle, but showed a tendency for higher total hydrocarbons (THC) and carbon monoxide (CO) emissions and lower particulate matter (PM) emissions. The JP-8 showed increases in THC and CO relative to the ULSD.

A practical and useful autonomous towed vehicle for port area inspection

This paper presents a novel underwater vehicle for port area inspection, which has various navigation modes (towed mode, autonomous mode and kite mode) to stand against fast and changeable sea currents. The property assures safe and reliable observation performance irrespective of current speed. Since in a port area sea currents are fast and complex, such a vehicle must be practical and useful for port area application. The unique point of the vehicle is the employment of an autonomous underwater vehicle (AUV) as a towed vehicle. In general, AUVs and towed vehicles are mutually contradictory. This paper describes the process of development to achieve the three different navigation modes. The system components and the results of computer simulations and towing tank tests to investigate the stability of the vehicle are presented. In addition, results of the first sea trial are also presented. These results show that the vehicle can navigate stably in the three different navigation modes.

Analysis of mesoscale productivity processes in the Adriatic Sea: Comparison between data acquired by Sarago, a towed undulating vehicle, and CTD casts

A modern approach to the study of pelagic ecosystems requires both an appropriate spatial and temporal resolution and a synoptic observation. For this reason, it is indispensable a rapid and high-resolution data acquisition along the water column. During the CNR project PRISMA II, four oceanographic cruises were performed in the Northern Adriatic Sea to analyse the high variability of ecological processes related to the frontal system. The SARAGO, a towed undulating vehicle, allowed a fine description of physical and biological acquired parameters (CTD, chlorophyll a concentration, photosynthetic efficiency, PAR). In succession, CTD and bottle carousel casts were performed to analyse physical and biogeochemical features. In this work, we compare the distribution and quantification of the relevant variables acquired by the two different sampling methods. A mathematical model was applied to estimate primary production.