Double Trailers Research Articles

Tyre lateral slip effect on off-tracking of a long combination vehicle

This paper evaluates the effect of tyre lateral slip on the off-tracking of a long combination vehicle (LCV) consisting of a semi-truck with 28-ft double trailers. A geometric model of LCV motion neglecting tyre slip and a high-order multi-body dynamic model in TruckSim® including tyre slip are developed and validated against other simulation and field test data. Tyre slip effect on off-tracking is measured by comparing the models' estimated off-tracking when the LCV netogiates 50, 75 and 100 ft (15.24, 22.86, and 30.48 m) radius curves at speeds of 1–16mph (1.6–25 km/hr). Two trailer payloads – 6000 lb/trailer and 14,500 lb/trailer – and three tyre-road friction coefficients – 0.85, 0.45 and 0.65 – were simulated. The simulation results indicate that tyre lateral slip increases – and thus off-tracking decreases – approximately to the second-order of vehicle speed for a given curve radius. It is also found that tyre lateral slip is negligible for speeds below 3–4mph (5–6 km/hr) in all simulated conditions. Additionally, as the path radius increases, tyre lateral slip and vehicle off-tracking sensitivity to vehicle speed reduce. The results suggest that for moderate speeds (>7mph (11 km/hr)), increasing vehicle payload and reducing surface friction coefficient result in an increase in tyre lateral slip that consequently reduces off-tracking.

Dimensionless Analysis of Rearward Amplification of Trucks with Single and Double Trailers: A Frequency Analysis

Dimensionless Analysis of Rearward Amplification of Trucks with Single and Double Trailers: A Frequency Analysis

Design and Social Change: An Architectural History of the University of California, Santa Barbara

ABSTRACT The University of California, Santa Barbara (UCSB), campus as it stands today appears as an architectural mash-up of midcentury modern institutional buildings, both low rise and high rise; a smattering of World War II–era wooden buildings; 1970s-style double wide trailers; and new science buildings built by a who's who of internationally famous architects. In this case study, the author shows how the UCSB campus's architectural history mirrors the post–World War II boom in educational facilities throughout California and the social, cultural, and architectural history of the region as a whole. The key to discovering this history is archival research, both at the University Archives at the UCSB Library, as well as at the architecture-specific Architecture and Design Collection at the Art, Design & Architecture Museum on campus. In this case study, the author explains how the architectural history can be traced through the archival records to more fully understand the history of the campus.

Headland turning optimisation for agricultural vehicles and those with towed implements

Abstract As an essential part of field coverage path planning process, mobile agricultural field equipment headland turning is a process that should be done in a manner that can maximise the equipment's operational efficiency through minimising the time or travel distance during the turning. However, this headland turning trajectory optimisation task represents a challenging dynamic nonlinear optimisation problem which is difficult to solve by using traditional indirect numerical methods. In this research, we investigated the possibility of using direct numerical methods to solve such a nonlinear optimisation problem in a restricted parameter neighborhood with constraints. We developed the kinematic models of the tractor and the tractor-implement(s) systems and formulated their headland turning optimisation problems through incorporating their models and the operational constraints. A range of headland turning scenarios from symmetrical bulb turn to fishtail turn and to turns with single and double trailers. With integration of the tractor and trailer models and by implementing the optimisation process with the TOMLAB/SNOPT software tool, results for diverse circumstances of the tractor/trailer headland turning scenarios were generated and illustrated in this paper.

How well a single-track linear model captures the lateral dynamics of long combination vehicles

ABSTRACTThe effect of centre-of-gravity heights on the high-speed performance measures of long combination vehicles including truck with double centre-axle trailers, Nordic, and A-double combination vehicles is investigated. The high fidelity three-dimensional models, used in this research, are validated against physical test data. These models are often accurate in terms of the actual dynamic behaviours of the vehicle. On the other hand, the simple yaw-plane single-track models with linear tires require less number of vehicle parameters. In this paper, it is investigated how accurate the estimations of performance measures are at high forward speeds by such single-track linear (STL) models. The influence of load height is especially studied. The high-speed performance-based standard or PBS measures considered are rearward amplifications of both lateral acceleration and yaw velocity; lateral load transfer; yaw damping and high-speed transient offtracking. The results show that tire relaxation has a large effect and it is rather easy to add to an STL model, so it is assumed to be modelled in STL. With realistically high payload and a required accuracy of PBS measures of approximately 10%, only the accuracy of rearward amplification of yaw velocity calculated by the frequency response is fulfilled by the STL. With low payload, the same statement is valid, but with around 5% in required accuracy. The roll dynamics effects are more important than the tire non-linearities.

A simulation-based comparative study on lateral characteristics of trucks with double and triple trailers

This paper investigates the lateral stability and manoeuvrability in long combination vehicles (LCVs), namely semi-trucks with 28-ft doubles, 28-ft triples, and 33-ft doubles, using TruckSim. In particular, the likelihood of rollovers, rearward amplification, and off-tracking are analysed among those LCVs using the multi-domain dynamic models developed in TruckSim. The efforts to validate the truck dynamic model against test results are also included. The simulation results show that trucks with triple trailers exhibit a larger rearward amplification, higher likelihood of rollovers, and larger off-tracking than trucks with double trailers. Additionally, the results indicate that increasing the trailer length from 28 to 33 feet does not increase the likelihood of rollovers or the rearward amplification. In fact, the longer trailers provide a slight amount of additional roll stability due to their longer wheelbase.

Are double trailers cost effective for transporting forest biomass on steep terrain?

Transportation of forest biomass on steep terrain involves logistical challenges. Trucks with large single trailers are often unable to travel on forest roads due to their narrowness, tight curves, adverse grades and limited areas to turn around. A shorter trailer must be used but then transportation capacity is limited by the trailer volume due to the low bulk density of the processed biomass, particularly when the biomass is dry. With double trailers, transportation capacity can be limited by allowable legal weight based on axle number and spacing. We developed a simulation model that explores the economic feasibility of using double-trailer configurations to transport forest biomass to a bioenergy facility from the grinder at a landing or from a centralized yard in Washington, Oregon and California. Results show that double trailers can be a cost effective alternative to single trailers under limited conditions in Oregon and Washington, but they are not a competitive option in California due to the state's transportation regulations.

Truck-and-Trailer Distribution Based on a Hybrid Evolutionary Algorithm

AbstractA simple DTT is a problem to design a hybrid trucking route for single and double trailers as a new version of the routing problem using sub-tours for servicing truck customers. The local optimization approach, 2-opt, is employed to optimize the route. An 0/1 integer linear programming model is built to segment the route that visits all customers, and choose a sub-tours combination that minimizes the incremental cost of the sub-tours. A hybrid evolutionary algorithm is built upon them to search for an optimal hybrid route. Numerical samples are provided to show the features of the DTT problem. The performance of the sub-tours combination optimization model and the evolution of the fitness of the algorithm with or without 2-opt are studied by simulation. The results demonstrate the validity of the proposed approach.

Safety performance of longer combination vehicles relative to other articulated trucks

This article helps improve the understanding about the safety performance of longer combination vehicles (LCVs) relative to other articulated trucks operating on rural highways, using evidence from the Canadian portion of the CANAMEX trade corridor. The analysis reveals that from a collision rate perspective, LCVs as a group have better safety performance than other articulated trucks. Turnpike doubles have the lowest collision rate of all articulated truck types (16 collisions per 100 million vehicle-kilometres of travel or VKT), followed by Rocky Mountain doubles (32 collisions per 100 million VKT). The collision rate for triple trailer combinations (62 collisions per 100 million VKT) is higher than the collision rates for tractor semitrailers (42 collisions per 100 million VKT) and legal-length tractor double trailers (44 collisions per 100 million VKT). These results are an important input for civil engineering and transport policy decisions concerning longer combination vehicle operations.

032 Application of nonlinear control theory to path tracking control of articulated vehicles with double trailers

032 Application of nonlinear control theory to path tracking control of articulated vehicles with double trailers

Applications of Nonlinear Control Theory to Path Tracking Control of Articulated Vehicles with Double Trailers

In this paper, we will design a path tracking controller for an articulated vehicle with double trailers using time scale transformation and exact linearization technique, which are developed in nonlinear control theory. We will show, in the simulation, that the proposed controller works satisfactorily, and the articulated vehicle with double trailers follows the desired path even when it is moving backward.

非線形制御理論を用いた多重トレーラーの直線経路追従制御

In this paper, we will design path tracking controller for an articulated vehicle with double trailers using time scale transformation and exact linearization technique, which are developed in nonlinear control theory. The controller will be designed in the following way. Firstly, we will describe the dynamics of the vehicle in a state equation whose time scale is the distance along the desired path (not the actual time t) . Then, we will exactly linearize this state equation using coordinate transformation and nonlinear feedback, and design a linear stabilizing controller for the linearized state equation.We will show, in the simulation, that the proposed controller works satisfactorily, and the articulated vehicle with double trailers follows the desired path even when it is moving backward.We can design path tracking controller for an articulated vehicle with multi trailers using the same strategy.