International Journal of Heavy Vehicle Systems (38 papers in press)
Introducing wheel-rail adhesion control into longitudinal train dynamics
by Qing Wu, Maksym Spiryagin, Colin Cole, Yan Sun
Abstract: Conventional Longitudinal Train Dynamics (LTD) simulations apply a number of assumptions regarding wheel-rail adhesion, and wheel-rail adhesion control has not previously been considered. This paper introduces locomotive wheel-rail adhesion control into LTD using co-simulation and parallel computing techniques. An in-house LTD simulator was connected to a commercial MBS dynamics simulator using the TCP/IP protocol. A heavy haul train with the configuration of three locomotives and 150 wagons was modelled. The wagons were modelled in the LTD simulator while the locomotives were modelled in the MBS simulator. The locomotive models were three-dimensional models that included wheel-rail contact models and adhesion control models. Simulations of locomotives were processed in parallel using three computer cores. Co-simulations with and without the consideration of curve lubrication were conducted and compared with a conventional LTD simulation. Computing times with and without parallel computing were also compared. The results show that, when compared with conventional LTD simulations, wheel-rail adhesion control generates evident differences for maximum traction forces, average train speeds, maximum in-train forces and force patterns. With three computer cores, parallel computing reduced the computing time by about 46% from about 3.7 hours to about 2.0 hours.
Keywords: longitudinal train dynamics; wheel-rail contact; adhesion control; traction modelling; parallel computing;co-simulation.
Ground-watching navigation for trailer-steering control
by Qiheng Miao, David Cebon
Abstract: This paper discusses two ground-watching navigation strategies for path-following control of a steered trailer at low speeds. Such systems provide navigation information by processing the features of the road surface in successive images. Theoretical performance of the systems was initially investigated in simulation. Field testing was conducted for three manoeuvres: a straight line, a lane change and a 90
Keywords: heavy goods vehicles; active trailer steering; ground-watching navigation; off-highway;.
Building a novel dynamics rollover model for critical instability state analysis of articulated multibody vehicles
by Qingyuan Zhu, Chaoping Yang, Huosheng Hu, Xiongfeng Wu
Abstract: Articulated wheel loaders in the construction industry have poor lateral stability and a high rate of accidents owing to their multibody structure and uneven working fields. In order to realise early rollover warning and active control, it is necessary to explore the mechanism of instability and the change rules of dynamics parameters. This paper proposes a novel dynamics rollover model with six degrees of freedom for modelling the instability process of an articulated wheel loader. The proposed rollover model is compared with a virtual prototype and a 1:5 scale-down physical prototype under four typical working conditions to verify its reliability, and its accuracy is investigated via a rotation motion under a constant steering angle under the critical state of rollover. Finally, the dynamics rollover model is used to investigate the influence of different kinematic parameters on lateral stability of an articulated wheel loader with steady-state margin angle as stability index.
Keywords: articulated wheel loader; dynamics model; lateral stability.
Improving curving performance of a straddle-type monorail vehicle by using semi-active devices
by Ali Suat Yıldız, Selim Sivrioğlu
Abstract: This paper is concerned with improving the curving performance of monorail vehicles, which are one of the modern mass transport systems, by using semi-active magnetorheological (MR) dampers. Controlling the curving dynamic of the monorail vehicles with semi-active devices is a new research area. The considered monorail vehicle has one segment supported by two bogies. As a secondary suspension, lateral and vertical MR dampers are taken into consideration in addition to air suspensions. Control performances of the robust Hinf and adaptive control are investigated and compared with a passive case along a designed road profile. Parametric uncertainties in running tyres and vehicle mass are taken into consideration in the control simulations. Simulation results show that the designed controllers improved the roll, yaw and vertical motions of the monorail vehicle when compared with uncontrolled and passive cases. These improvements provide better comfort and safer conditions, and a small turning radius can be achieved by monorail vehicles equipped with the semi-active suspension system.
Keywords: semi-active suspension; MR damper; adaptive controller; monorail vehicle; Hinf control.
A virtual test platform for railway draft gear designs
by Qing Wu, Colin Cole, Maksym Spiryagin, Weihua Ma, Shihui Luo
Abstract: Draft gears are important shock absorbers in railway vehicle operations. Draft gear design and assessment processes commonly use results from physical drop-hammer tests, vehicle impact tests and laboratory rig tests, which all use quite different impact velocity ranges and impact severities from each other. Owing to the velocity-dependent characteristics of friction and viscous damping, draft gears can be better designed and assessed by using comprehensive draft gear test simulations. This paper developed a multipurpose virtual test platform for draft gear designs; the virtual platform can conduct drop-hammer test simulations, vehicle impact test simulations and laboratory rig test simulations for different types of draft gear using different draft gear models. The development for the virtual platform has used a versatile draft gear model that can simulate a number of different draft gear designs by using one model template; it has also used a multipurpose simulation strategy that can simulate different draft gear tests using the same dynamics model. Three virtual test examples are also presented in this paper.
Keywords: draft gear design; virtual platform; drop-hammer; vehicle impact; laboratory rig.
Torsional vibrations in heavy-duty truck powertrains with dual mass flywheels
by Lina Wramner
Abstract: Many of the measures taken to improve combustion engine efficiency lead to higher torsional vibrations. For heavy-duty commercial vehicles it is foreseen that the conventional flywheel and clutch will not be able to sufficiently reduce those increased engine torsional vibrations to the driveline. In this paper, the steady-state torsional vibrations in a heavy-duty truck powertrain are studied. The focus is engine excited vibrations at high load within operating speed range. Vibration phenomena in a conventional heavy-duty powertrain and in powertrains equipped with dual mass flywheels are studied. It is shown how the use of a dual mass flywheel can enable down-speeding and increased engine torque with maintained or reduced levels of torsional vibrations.
Keywords: torsional vibrations; powertrain; driveline; heavy-duty truck; dual mass flywheel; DMF; resonances; simulation.
An innovative straddle monorail track switch design for the personal rapid transit
by Chih-Hung Li, Zong Jun Lu
Abstract: An innovative track switch design is proposed for a straddle monorail system that may serve as a personal rapid transit (PRT) system. Previously, a PRT system using the monorail design was thought impossible. Here we introduce onboard guide wheels on the monorail vehicles to be the only movable parts that direct the cars to different paths. Each vehicle activates its own switching mechanism and does not need to wait for the movement of the heavy track beams anymore. Guideways and ground rails accommodated by a switch platform are designed to replace the monorail track beams. To verify the system performance, a model monorail loop and a vehicle were built for testing. Test results and analyses show that the monorail vehicles have enough momentum to traverse the switch area without power, and the required headway for the proposed system is much less than the target of 10 seconds.
Keywords: monorail; PRT; personal rapid transit; track switch; headway.
Prediction and analysis of semi-low-floor bus driver seat vibrations by using the response surface methodology
by Medisetti Jaganmohan Rao, S.P. Sivapirakasam
Abstract: In India, Semi-Low-Floor (SLF) buses were used as shuttles within the city. The main objective of this paper is to develop a quadratic model for prediction of driver seat vibration and analysis of relationship between the seating parameters and driver seat vibrations. Response surface methodology was used to develop the regression model in SLF bus driver comfort. In the development of the predictive model, the seating parameters backrest inclination, horizontal distance from the ABC pedal, foam thickness and speed were considered as model variables, and seat vibration was considered as a response variable. The statistical analysis showed speed was the most significant process parameter to influence seat vibration. Other parameters were found to be insignificant but the interactions among them were found to be significant. Apart from objective analysis, the subjective assessment parameters comfort, visibility and confidence also studied for all the trials. At back-rest inclination 90
Keywords: semi-low-floor bus; DoE; process parameters; weighted acceleration; response surface method; regression model.
Dynamic analysis and design optimisation of a heavy military vehicle
by Burak Can Çiçek, Bülent Acar, S.Kemal İder
Abstract: This paper investigates the dynamic response of a heavy military vehicle that is subjected to a dynamic firing load while it is settled on its outriggers. This dynamic behaviour is one of the major design factors of a launching vehicle. Two different finite element (FE) models are created in ANSYS software to obtain the dynamic behaviour of the launching vehicle. The first model is a detailed finite element model and the second model is a simple and fewer degrees of freedom (DOF) parametric FE model, which is created with the ANSYS Parametric Design Language (APDL) in order to perform the design optimisation by swiftly changing the parameters such as clamp attachment positions on the chassis, outrigger deployment and outrigger case cross-section.
Keywords: heavy military vehicle; dynamic analysis; finite element; design optimisation; outrigger.
Study of tyre-terrain interaction of a military vehicle
by Lucas Sousa, Ricardo Costa Neto
Abstract: Wheeled military vehicles are often used on deformable terrains. In order to understand their performance, a tyre-terrain interaction model is required. The aim of this paper is to present the application of semi-empirical tyre models based on Wong-Reece models in order to investigate the drawbar pull, the resistive torques, the sinkage and the stress distributions beneath each tyre of a six-wheeled military vehicle. An accurate prediction of terrain forces is of interest to engineers and vehicle designers to understand the vehicle performance. Furthermore, a heavy military vehicle can be immobilised owing to particular tyre-terrain properties. In a combat situation, an immobilised vehicle can be dire. The military vehicle was simulated on compact sand and dry sand, when the tyre behaves like a rigid wheel in driven and towed conditions.
Keywords: military vehicles; wheel mechanics; deformable terrains; mobility prediction; Wong-Reece theory.
Experimental-theoretical modelling of the lateral sloshing in rail tankers
by Jose A. Romero Navarrete, Frank Otremba, Alejandro A. Lozano Guzmán
Abstract: The objective of this paper is to describe and to validate a simplified pendulum-analogy model to simulate the interaction of a liquid cargo with its carrying vehicle. For that purpose and scope, a scale-down testing rig is proposed to assess the effect of a sloshing cargo on the level of dynamic forces developed at the wheel-rail interface under a lateral perturbation. The resulting testing rig consists of a rectangular container, spring-supported on a two wheelset bogie having a scale down of 1/10 with respect to a full-size equipment. The chassis and cargo representing the sprung mass, and the wheelset representing the unsprung mass of the resulting mechanical system. The testing rig is used to validate a simple pendulum-based, simplified three degree of freedom mathematical model, of the response of a partially filled container to lateral accelerations. The model comprises a full analogy of the sloshing cargo with the simple pendulum, where the tension in the pendulum bar perturbates the sprung mass. The length of the pendulum is set according to validated methodologies. The resulting mathematical scheme reveals a high correlation with the experimental output, on the order of 99%, while some other performance measures, related to the peak forces and the range of variation of the wheel-rail forces, also show good concordance with the experimental results. Additional simplifications made on the model further suggest that the length of the pendulum, the position of its pivot, and the track width, are the most important parameters influencing
the magnitude of the wheel-rail forces.
Keywords: sloshing; rail tankers; pendulum analogy; experimental modelling; mechanical fatigue.
Bidirectional adaptive cruise control for intelligent vehicles
by Chentong Bian, Guodong Yin, Liwei Xu, Ning Zhang
Abstract: Most of the previously investigated adaptive cruise control methods focused on maintaining a safe front clearance of the host vehicle. Owing to fault or heat fading, the vehicle behind an intelligent vehicle may lose part of braking performance and collide with the intelligent vehicle. Thus the control system of an intelligent vehicle should simultaneously maintain the front and rear clearances on such a critical condition, which is seldom discussed before. In this study, a bidirectional adaptive cruise control algorithm is proposed to reduce such collisions. Simulations have been done to confirm the validity of the proposed algorithm. The simulation results show that the proposed algorithm can reduce the collisions caused by the following vehicle with low braking performance, which cannot be resolved by traditional adaptive cruise control. Thus, compared with the traditional adaptive cruise control, the proposed algorithm can improve the safety of intelligent vehicles in collision avoidance.
Keywords: intelligent vehicle; bidirectional adaptive cruise control; collision avoidance; adaptive cruise control.
Using a mobile app to estimate whole-body vibration and seat isolation performance in surface mining
by Alan G. Mayton, Brian Y. Kim
Abstract: The study objectives were twofold: 1) determine whether the whole-body vibration application (WBV app) may effectively serve as a simple tool for monitoring whole-body vibration exposure; 2) assess when the vehicle seat may need adjustment, repair, or replacement. Data were collected on 17 mobile mining vehicles and equipment at six surface operations. Comparing the WBV app to the Siemens/LMS reference system showed excellent correlation (r = 0.998 and 0.987, respectively), for frequency-weighted-root-mean-square acceleration (aw) and vibration dose value (VDV) normalised to an 8-hr shift. Seat performance, using the mobile app, showed greater variation, yet high positive correlations (r = 0.896 and 0.936) for the aw and VDV computational methods, respectively. Hence, the WBV app demonstrates potential as a low-cost instrument to measure WBV exposures for mobile equipment operators and the capability to estimate seat performance or seat effective amplitude transmissibility (SEAT) when used on two iPod Touch devices.
Keywords: whole-body vibration; mobile iPod app; surface mining; haul trucks; loaders; dozers.
Performance comparison of MD523 and SF400 bogie when passing through different turnouts
by Mahdi Naseritaheri, Shahin Yousefi, Majid Shahravi
Abstract: In recent years, the study of the dynamic behaviour of the high speed train has been taken into account when passing through the turnout. Some of these studies include examining wheel and rail dynamics when crossing the turnout nose and extracting the wheel's contact forces. The dynamical behaviour of passenger high-speed bogies during passage through the turnout is one of the most important factors in the safety of the vehicle. When increasing the speed of wagons when passing through the turnout, safety parameter and wheelset forces should be considered. The statistics have shown that 40% of derailments have taken place owing to the inside of the turnout or the defect of the turnout. The purpose of this paper is to study and analyse the dynamics parameters of passenger wagon and safety of a bogie, such as the derailment and the forces of the wheelset when passing through the turnout with different turnout rail profiles, because the type of turnout rail profile and geometry of turnout affect the dynamic performance of the bogie. In order to investigate this, the simulation of a wagon in a multi-mass dynamic (MBS) UM software has been used on turnouts with different rail profiles and radius of turnout. As the results show, the geometric features of the turnout, such as its radius and turnout rail profile, have greatly influenced the dynamics of the wagon.
Keywords: turnout; derailment coefficient; high speed bogie; dynamic forces; turnout geometrical specification.
Investigating the effects of off-road vehicles on soil compaction using FEA-SPH simulation
by Fatemeh Gheshlaghi, Aref Mardani, Arash Mohebbi
Abstract: The study of terrain-tyre interaction using simulation methods allows for accurate prediction of parameters, such as soil density and rut depth, that are either time-consuming and expensive or inaccessible with experimental methods. This research focuses to predict and evaluate the soil compaction after off-road tyre traffic in different vertical loads on the tyre. Soil-tyre interaction is simulated using the Smoothed-Particle Hydrodynamics-Finite Element Analysis (SPH-FEA) techniques in Pam-crash software. In order to evaluate the simulation model, tests were conducted using a single-wheel tester in soil storage with different numbers of the pass and various loads. Soil density and rut depth were measured and compared with the simulation data. The results indicate that the tests and simulation data are in good agreement with the coefficient of determination of 0.94. The tyre with higher pass number makes greater rut depth and consequent greater soil density. The intensity of soil compaction due to vehicle weight is discussed in the results.
Keywords: tyre-soil interaction modelling; rut depth; soil density; finite element analysis; smoothed-particle hydrodynamics; single-wheel tester.
Vibration analysis of half rail vehicle model with ten degrees of freedom based on mechanical-electrical analogy theory
by Fatih Pehlivan, Ismail Esen, Cihan Mizrak
Abstract: The aim of this paper is to show that vibrations of ten degrees of freedom (10 DOF) half rail vehicle models obtained by both mechanical mechanism and equivalent electrical circuit are identical. Firstly, the system was modelled and then a free body diagram was formed. Afterwards, motion equations of the system were determined using Lagranges method. The mechanical circuit was constructed using force equations and its equivalent electrical circuit was obtained using the Kirchoff current law (KCL) and force-flow similarity. Then, a schema was formed by means of MATLAB Simulink to analyse the vibrations of the rail vehicle model. To make simulations, the speed of the rail vehicle model was selected as 400 km/h. As input, track irregularities in American Railway Standard and non-random irregularities were applied to the all wheels separately. As a conclusion, it was observed that the signals taken by both the mechanical mechanism and its equivalent electrical circuit appeared similar, and the vibration analysis of a complex mechanical system can be modelled not only mechanically but also electrically.
Keywords: mechanical-electrical analogy; half rail vehicle; vehicle vibration; modelling; simulation.
Identification of railway track quality and safety through the dynamic inertial response of railway carbody and truck
by Roberto Spinola Barbosa
Abstract: An extended version of the inertial measuring system installed in the carbody and trucks is used to evaluate the railway track quality and safety, observed from the vehicle dynamic performance point of view. The system measures the dynamic movements of the carbody and is extended to observe also the truck attitude and suspension torsion due to irregular track geometry. The values measured are used in an inertial navigation algorithm with a Kalman filter to identify the full vehicle attitude, including angular positions and accelerations. System equations for the inverse carbody and truck dynamic problem, augmented with the suspension torsion equation, is solved to directly estimate the wheels' driving forces that are directly correlated with the vehicle safety. A dimensionless safety index (SI) is proposed to evaluate track quality and safety. Values obtained are used to quantify track harmful locations. The results of a test campaign, travelling on the irregular track in a conventional train, identified the full vehicle and trucks attitude and the suspension torsion angular movement. The SI and the location of the potentially most hazardous region for track maintenance purposes were identified. Good correlation between the SI and measured track geometry is observed, hence this method is a promising technique.
Keywords: dynamic; safety; vehicle; railway; track.
A modified Odenthal rollover index algorithm for tractor-semitrailer using steering and vehicle speed inputs
by M. Hafiz Harun, Khisbullah Hudha, Pakharuddin Mohd Samin, Saiful Anuar Abu Bakar, Amer Noor Hafizah, Abd Kadir Zulkiffli
Abstract: One of the main factors that cause tractor-semitrailer accidents is vehicle rollover instability. Owing to the size of the vehicle, any accident will significantly affect life, property damage and the tractor-semitrailers components as well as the surrounding environment. Therefore, an early warning indicator of an impending vehicle rollover is essential, especially to the tractor-semitrailer driver in order to control the vehicle and eventually avoid an accident. In this study, a rollover index algorithm is proposed by integrating the modified Odenthal rollover index algorithm with driver steering and vehicle speed inputs instead of lateral acceleration. The modified Odenthal rollover index algorithm performance is evaluated by conducting experiments involving the step-steering manoeuvres, subjected to various speeds and load conditions, in the TruckSim driving simulator and MATLAB/Simulink software. It is observed from the results that the modified Odenthal rollover index algorithm produces 12.4% faster time-to-warn than the Odenthal rollover index for the driver and offers adequate time-to-respond to initiate the corrective actions. Thus, the modified Odenthal rollover index algorithm creates a better early warning system and can prevent rollover accident significantly.
Keywords: tractor-semitrailer; rollover index; time-to-warn; time-to-respond; step-steering manoeuvre.
Determination of tyre-ground interaction parameters through image processing in Matlab
by Petru Rosca, Marius-Ionut Marmureanu, Tudor-Viorel Tiganescu, Catalin-Mihai Pirvulescu, Irina-Maria Bindac, Calin Doru
Abstract: The tyre-ground interaction represents a topic highly debated but still many aspects are to be further studied and analysed. In this context, one representative parameter is the wheel ground pressure its influence is associated with the design of rigid pavements, with the restraints imposed by the aircraft cargo capacity and with the vehicle off-road capabilities, at least. In fact, the wheel ground pressure represents the ratio between wheel load and contact patch area. If the weight of a vehicle and its distribution on wheels can be easily measured, the contact patch area quantification requires either sophisticated and expensive to determine, or the compromise of obtaining inaccurate results by using more or less adequate predictive formulas. This paper presents a modern and efficient method, through image processing in Matlab, which can be used in order to accurately determine the contact area and other related parameter such as mobility area, the maximum contact length, and the maximum contact width. It also proposes new prediction equations for the contact area and for the mobility area based on experimental data related to Continental 14.00 R20 tyre type. The applicability on the tyre-ground interaction should be seen as a particular case, at least for the image processing method, its helpfulness being noted in many areas, as well topography, tribology, and medicine.
Keywords: tyre; pressure; area; image; Matlab.
Investigation and analysis of hydraulic cylinder cushioning of excavator
by Govindarajalu Venkatesan, Sadagopan Palaniswamy
Abstract: Hydraulic cylinders are the linear actuators used in applications such as industrial, agricultural and construction equipment like excavators. The backhoe of an excavator can dig with enormous force and its movements are carried out by the hydraulic system. The piston movement, from rear to front end, swings the backhoe in seconds and if it is not slowed down at the end, the swing stops suddenly resulting in metal to metal contact causing jerk, vibration and bounce due to inertia effect. This phenomenon leads to failure of seals and other components causing higher maintenance cost. The size and profile of the cushion nose plays an important role in slowing down the piston movement. Hence in this work, an attempt is made to investigate the cushioning effect by changing the size and profiles of the cushion nose based on DFMA and to analyse the pressure variation with respect to piston movement using CFD and the results are presented. In addition, from the results, analysis is carried out using DOE to find the most significant factor that affect the back pressure and smooth transition of pressure. It is found that the cushion nose with curved internal profile produced better results than the existing taper design cushion nose profile and other profile variations.
Keywords: hydraulic cylinder; cushioning; excavator; backhoe; cylinder cushion; cushion nose profile; deceleration; actuator; computational fluid dynamics; DFMA; DOE.
A review of fuel cell technology for commercial vehicle applications
by Tommi Jokela, Bo Gao, Bill Kim, Matthias Wellers, Jun Peng
Abstract: Commercial vehicles contribute a significant and increasing portion of road transport greenhouse gases, which is leading to regulators introducing CO2 limits for these vehicles. The demanding energy storage requirements of many commercial vehicle applications are extremely difficult to meet for pure battery electric vehicles due to the limited energy density of batteries whereas hybrid commercial vehicles that include combustion engines can only provide limited amounts of emission reductions. Fuel cells appear to be the only viable propulsion technology that is able to meet commercial vehicle application requirements with zero local greenhouse gas emissions. The particular strength of fuel cell vehicles compared to battery electric vehicles is their high energy density, making them particularly suitable for commercial vehicle applications that often require long driving ranges. Since almost all fuel cell vehicles also contain a high voltage battery, some additional complexity is introduced since the hybrid energy storage system must be sized and controlled appropriately. An understanding of the strengths and weaknesses of each system is therefore essential in fuel cell vehicle design. The aim of this technology review is thus to provide an overview of fuel cell technologies in commercial vehicle applications including assessments of alternative powertrain and fuel cell types, advantages and disadvantages of fuel cell and battery systems and the implications of these on the powertrain sizing as well as control considerations of fuel cell vehicles.
Keywords: fuel cell; commercial vehicles; powertrain; energy management strategy.
Development of an integrated active yaw controller on soft terrain
by Hossam Ragheb
Abstract: Off-road vehicle maneuverability on soft terrain is strongly affected by the tyre-soil interaction characteristics. Remarkable enhancements in active vehicle safety systems depend on different control systems aiming to enhance off-road vehicle mobility. In this paper, an integrated active yaw control system, Anti-Lock Braking System (ABS) and Traction Control System (TCS), for an (8x8) multi-wheeled combat vehicle operating on soft terrain is developed. A TruckSim-MATLAB/Simulink vehicle model was developed to verify the developed integrated control system on soft soil. The presented integrated control system revealed an enhancement in vehicle directional stability and traction performance. Besides, it should be mentioned that the soil type has a great effect on controller efficiency as it is limiting the applied torque by the developed controller.
Keywords: off-road; mobility; active yaw control; anti-lock braking system; traction control system; TruckSim; MATLAB/Simulink; multi-wheeled vehicles; soft soil.
Developing an analytical model for prediction of tyre rolling resistance on moist soils
by Fatemeh Gheshlaghi, Aref Mardani, Arash Mohebbi, Hamid Taghavifar
Abstract: This paper presents a Finite Element Analysis Smoothed Particle Hydrodynamics (FEA-SPH) technique to predict the rolling resistance of an agricultural tyre over moist soils. Firstly, dry clay-loam soil is modelled using hydrodynamic elastic-plastic materials and the water behaviour is captured using the Murnaghan equation of state. Then, to simulate moist soil, water layers are added to the dry soil surface. Soil calibration is performed based on experimental data using a bevameter and through the direct shear tests under similar operating conditions. A free-rolling Bias-ply tyre (size 8.25-16) employed for the experiments was modelled using the FEA method. The interface contact between tyre and soil is described based on a node-symmetric node-to-segment contact with edge treatment. The obtained simulation results for rolling resistance account for different levels of soil moisture, traffic and vertical load. Finally, the proposed model is validated using experimental data obtained from a single-wheel tester in the controlled test condition.
Keywords: rolling resistance; smoothed-particle hydrodynamic; finite element analysis; moist soil; vertical load; soil bin.
Fractional order state feedback control for improved lateral stability for tractor-trailers in platooning
by Rasheed Abdulkader, Roy McCann
Abstract: This paper develops an improved tractor-trailer platooning operation for an evasive highway manoeuvre situation by implementing a fractional order state feedback control method. This increases the lateral stability of commercial heavy vehicle platoons and thereby improves energy savings and safety. The control method is developed based on a nonlinear model for a tractor-trailer in platooning formations. A method for analysing heavy vehicle dynamics is presented. To validate the proposed control algorithm, the complete nonlinear system is evaluated in MATLAB/Simulink to account for the interaction of truck dynamics during the platooning operation. Simulation results with varying the truck speed and the trailer load demonstrate the robustness of the proposed fractional order state feedback control scheme for an evasive manoeuvre scenario. Thus the proposed control scheme is compared with a professional driver for an emergency highway lane manoeuvre. Overall results confirm that the proposed controller improves tractor-trailer response time as compared with a professional truck driver along with increased energy savings and reduced fuel consumption during the platooning operation of the tractor-trailer.
Keywords: lateral stability; active front steering; platooning; fractional order control; tractor-trailer dynamics.
Liquid cargo effect on load transfer under orthogonal accelerations
by Jose A. Romero Navarrete, Frank Otremba, Alejandro A. Lozano-Guzman
Abstract: A methodology is proposed for the experimental analysis of the liquid cargo effect under combined orthogonal accelerations. When simultaneously subjecting the vehicle-cargo system to longitudinal and lateral accelerations, the vehicle is set obliquely on a tilt table. The experimental outputs suggest that there is a significant effect of the liquid cargo on the lateral load transfer ratio (LTR), of the order of 20%, which is attributable to the resulting shifting of the liquid cargo
Keywords: sloshing; liquid cargo; cargo shifting; lateral load transfer; braking in a turn manoeuvre.
Study on super-wheelbase preview controller/algorithm for internet of vehicles suspension system used in a heavy vehicle fleet
by Ce Yuan, Jiang Liu, Xilong Zhang, Bilong Liu, Yushun Wang
Abstract: Most truck fleet transportations show typical repetitive features in vehicle models, routes and cargos. So the Internet of Vehicles (IoV) theory could be easily introduced into the active control for truck suspensions. We establish a communication network structure in which paired vehicles are basic elements, and the geographic information system is treated as a detection auxiliary. The new design reduces the overall communication demand for suspension control data. Based on this simplified IoV system, a new super-wheelbase preview control method is proposed. The optimal vehicle distance between paired trucks is calculated by the particle swarm optimisation. The traditional wheelbase preview algorithm is improved by using two equivalent parameters. The rear truck shows better comprehensive suspension performances than the front one. Finally, we perform a simple objective optimisation in the truck pairs sequence. The convergence results show that, with the help of the IoV suspension system, the sixth and after trucks can get the minimised body acceleration in the fleet's first loop.
Keywords: suspension; IoV; super-wheelbase preview; particle swarm optimisation.
Dynamic stability analysis of a high speed diesel engine turbocharger subjected to aerodynamic loads and engine-induced vibration
by Ali Alsaeed, Salem Bashmal
Abstract: The dynamic behaviour of a high-speed turbocharger supported on floating-ring bearings is investigated under the effect of engine-induced vibrations and aerodynamic loads. A finite-element model is developed for the turbocharger to predict the nonlinear transient response while engine excitations are simulated as time-varying force functions on the rotor bearings. Damping and stiffness parameters of the floating-ring bearings are estimated by solving the 2-D Reynolds equation. The engine-induced excitations are combined with compressor radial aerodynamic forces to obtain the total response numerically. Modified non-circular volute theory is used to calculate radial thrust loads due to aerodynamic effects. The numerical predictions agree with the experimental observations of a fully-loaded turbocharger that show no significant second harmonic frequency amplitudes of the engine frequency. However, the engine frequencies are at comparable amplitudes with the Sub High and 1X amplitudes at higher speeds, where the radial aerodynamic loads are not significant (no-load). The results of the present work indicate that, in the subsynchronous region, some amplitudes at the engine-excitation frequency are also observed at the second harmonic for high speeds. Moreover, the dynamic stability of the turbocharger is significantly influenced by the variation in the magnitude of the engine-induced vibration. The numerical predictions are consistent with the previous experimental tests for a typical turbocharger.
Keywords: turbocharger; stability; transient response; aerodynamic forces; vibrations.
Active boom stabiliser of wheel loaders using optimum fuzzy controller
by Abdulaziz Al-Fadhli, Emad Khorshid
Abstract: Wheel loaders are exposed to several disturbances while travelling from one location to another to carry loads. Low frequency disturbances are coming from crossing speed humps or travelling over rough terrain. Reducing the vibration disturbances on wheel loaders will increase the load-handling efficiency by the boom-bucket element, which increases productivity. Towards reducing the risk of load drooping and reducing boom oscillations, a novel active boom control system with an optimised fuzzy logic controller is presented in this paper. For cost-effective purposes, the fuzzy boom active controller uses the existing boom-lifting electro-hydraulic component to attenuate boom oscillation. Indeed, the designed fuzzy logic controller applies measurable and accessible system states as input variables, while its structure in terms of rule base and scaling factors is optimised using a particle swarming algorithm. Numerical results showed that the proposed method succeeded in effectively damping the boom oscillation under several types of road disturbance and different driving speeds.
Keywords: wheel loaders; active damping; numerical simulation; fuzzy controller; design optimisations; mathematical modelling.
Studies on critical hunting speed and running safety of conventional railway vehicles moving on curved tracks
by R.K. Sajeev, Sujatha Chandramohan
Abstract: Critical Hunting Speed (CHS) and running safety are factors to be investigated for the study of the dynamic behaviour of a railway vehicle. In this paper, a numerical investigation of the nonlinear dynamic behaviour of a railway vehicle running on tracks of various radii is carried out using a mathematical model of the combined system. The computation of vehicle-track combined systems dynamic behaviour with single and two-point contact scenarios of wheel-rail are not reported in any literature. Using these contact scenarios, nonlinear CHS and safety of the vehicle are evaluated. The vehicle model consists of a 25-degrees-of-freedom (25-DOF) system with four wheel-sets, two truck frames, two bolsters and a carbody. Both wheel-axle sets and the truck frames have lateral displacement and yaw angular displacement; each bolster has yaw angular displacement and the carbody has lateral displacement, roll and yaw angular displacement. The track is idealised as a laterally flexible spring-mass-damper system. Wheel-rail geometry and its contact geometry for characterisation of frictional creep forces and the contact between truck frame and bolster as Coulomb friction element are the nonlinearities adopted in the model. Linear damping and stiffness are assumed for lateral and longitudinal primary and secondary suspensions. The model is solved using the Runge-Kutta fourth-order method. The transformed state space equations are solved in the time domain to obtain the dynamic response of a conventional railway vehicle. Limit cycle type oscillation is adopted to evaluate the nonlinear CHS. Furthermore, a parametric study is carried out to analyse the influence of wheel-rail geometric and material parameters on vehicle running safety, which is based on derailment quotient and offload factor.
Keywords: critical hunting speed; running safety; single/two-point wheel-rail contact; nonlinear creep model; curved tracks.
Dynamic characteristics analysis of tubular stand-off-layer sandwiched structure used in driving sprocket
by Bijuan Yan, Zekun Liu, Wenjun Zhang, Shizhong Liu
Abstract: In order to reduce the severe vibration of the driving sprocket of a crawler construction vehicle, a tubular stand-off-layer sandwiched structure (TSSS) is used, and its corresponding vibration model is established. The tensile test and MATLAB software are used to fit the material characteristic parameters of the damping layer and stand-off-layer. Under the common working conditions of bulldozers (bulldozing and cutting),the vibration characteristics and transient dynamic response of three different multi-layer damping structures (three-layer, five-layer tubular constrained damping structure, four-layer TSSS) are discussed using ANSYS software. During the dynamics analysis, the loads are divided into two cases, one is that the load changes with the rotation angle of the driving sprocket, and the other one taking time as the dependent variable. The results show that the damping vibration-reducing characteristics of the four-layer tubular stand-off-layer sandwiched structure are better than those of the three-layer and five-layer tubular constrained damping structure (TCDS), the dynamic response amplitude of the damping layer is half that of the other two structures, the acceleration response amplitude is far less than that of the three-layer TCDS, and the force transfer rate range is also the smallest, and there is a minimum value. It can be found that the existence of the stand-off-layer can not only increase the shear strain of the damping layer and make the structure consume more energy, but also improve the vibration isolation efficiency and reduce the vibration response of the structure. This research can lay a good foundation for the dynamic analysis of drive wheel vibration reduction and tubular damping structure and the optimisation of structural parameters in the future.
Keywords: driving sprocket; tubular structure; stand-off-layer; damping vibration-reducing characteristics.
A thermal braking model of the entire heavy vehicle wheel assembly
by Joshua Subel, Frank Kienhofer
Abstract: Overheating of heavy vehicle brakes and surrounding components can have fatal consequences. The design specifications of the entire heavy vehicle wheel assembly, including the rim material and wheel configuration, impact the brake, axle, rim and tyre temperatures. Consequently, it is important to model the entire heavy vehicle wheel assembly. In this study, a thermal model to predict the temperatures of the brake, axle, rim and tyres is developed and validated using experimental braking results for single and dual wheels using steel and aluminium rims. The use of the model is illustrated by analysing the component temperature responses of a conceptual carbon fibre reinforced polymer (CFRP) rim to 2:5 kW of continuous braking. A CFRP rim would reduce the conduction of heat from the brakes into the tyres, resulting in a tyre temperature reduction of up to 35%. This positive benefit is at the expense of higher brake and rim temperatures.
Keywords: brake overheating; tyre failure; bearing failure; lumped mass modelling; transient thermal analysis; carbon fibre reinforced polymer; rim materials.
Track gauge selection of medium-low speed maglev and its impact analysis
by Dinggang Gao, Weihua Ma, Tie Li, Zhenhong Wang
Abstract: In view of the lack of a standard gauge for current medium-low speed maglev, the relationship between gauge and vehicle length, vehicle width and basic weight of the maglev vehicle is studied in this paper. The effects of increased gauge from 1700 mm to 2000 mm on levitation capacity, anti-rolling capacity, device suspension space and F-rail magnetic-pole-face height difference for curve negotiation are analysed. The result indicates that the size of gauge is generally independent of vehicle length and is positively related to vehicle width and vehicle weight, but the reasonable internal design and layout can effectively control the vehicle weight. With increasing gauge, the force of the levitation electromagnet vertical force to balance the rolling moment, the rolling angle and the maximum vertical height difference between the inner and outer magnetic pole faces of the F-rail all decrease. Overall, the vehicle levitation capacity and the anti-rolling ability are both improved. The maximum bending moment of the sleeper is increased, and the lateral dimension of device suspension space of motor and longitudinal beam is increased.
Keywords: medium-low speed maglev; track gauge; curve negotiation; dynamics performance.
A novel heavy-duty truck reversing safety control based on pedestrian tracking using fisheye stereo vision
by Miankuan Zhu, Lei Han, Fujian Liang, Lei Wu, Chaoxing Xi, Zutao Zhang
Abstract: Heavy-duty trucks have caused many reversing accidents owing to the large blind area of the body, so the safety of reversing assistance has attracted more and more attention. In this paper, we present a novel heavy-duty truck safety approach for reversing based on pedestrian detection and tracking using fisheye stereo vision. Firstly, an elliptical plate is proposed to calibrate a fisheye camera, and a disparity map is computed using the binocular fisheye camera. Secondly, a pedestrian is detected after the fisheye images are corrected. Thirdly, an improved pedestrian tracking algorithm based on Consensus-based Tracking and Matching of Key-points for Object Tracking (CMT) algorithm combined is applied to track pedestrians. Finally, a heavy-duty truck reversing speed control method is proposed to avoid collisions and improve the safety of truck reversing. This system has been tested on a van truck. Experiments demonstrate the viability of the proposed heavy-duty truck reversing safety system.
Keywords: heavy-duty truck; fisheye stereo vision; pedestrian detection and tracking; reversing safety control.
Algorithm for inverse determination of derailment coefficient by using instrumented wheelsets
by Milan Bižić, Dragan Petrović
Abstract: The main indicator of the running safety of railway vehicles is ratio between lateral and vertical forces in the wheel-rail interaction, known as derailment coefficient. Its exact determination has a huge significance in the development and certification phases of railway vehicles. The most reliable determination of wheel-rail interaction forces is based on experimental testing, by using instrumented wheelsets, which is otherwise prescribed in appropriate international regulations. This paper presents a unique algorithm for inverse determination of wheel-rail interaction forces, i.e. derailment coefficient, based on the measurement signals obtained from instrumented wheelset. The blind signal separation (BSS) and method of independent component analysis (ICA) are applied. Verification is carried out on an example of a wheelset of a freight wagon, based on the wheels' FEM model. The obtained results confirm a high efficiency and accuracy of the developed algorithm, whereby the estimated error of inverse identification is less than 5%.
Keywords: inverse determination; wheel-rail interaction forces; derailment coefficient; experimental testing; running safety; railway vehicles; instrumented wheelset.
Intelligent control strategy for a heavy vehicle compaction system DYNAPAC CC6200
by Hocine Chebi
Abstract: This paper proposes a GA-LOS-PI controller-based four-level control system that accurately evaluates pavement compaction effect of DYNAPAC CC6200 Autonomous Articulated Vehicle (AAV). In the evaluation layer, various performance indicators are evaluated, including stability, rapidity and accuracy when trajectory tracking, and the ratio of required compaction to actual compaction once and twice and compaction repeatability index when pavement compacting. In the decision and control layer, an incremental PI controller is used as the main control strategy, Line Of Sight (LOS) guidance is introduced to eliminate system control lag, and Genetic Algorithm (GA) is used for searching the best proportional and integral parameters of the incremental PI controller and the radius parameter of LOS guidance. In the sensor level, a simplified sensor configuration is used to reduce overall cost. The comparative simulation results of no controller, the traditional incremental PI controller, LOS-PI controller with Human Driving Experience Initial Control Parameters (HDEICP), GA-LOS-PI controller with Random Initial Control Parameters (RICP) and GA-LOS-PI controller with HDEICP manifest evidently that the proposed GA-LOS-PI controller with HDEICP has almost no steady-state error, no overshoot, and short settling time, that is, GA-LOS-PI controller-based four-level cost-effective pavement compaction system meets the project needs well.
Keywords: pavement compaction; four-level system; autonomous articulated vehicle; genetic algorithm; PI controller; Line of sight guidance; trajectory tracking; DYNAPAC CC6200.
Special Issue on: Recent Advances in Active Safety Control Systems for Commercial Vehicles
Investigating the active suspension performance using 2/ robust controller combined with particle swarm optimisation
by Hamid Taghavifar, Leyla Tagahvifar, Aref Mardani
Abstract: A robust controller design technique for vehicle active suspension systems is investigated, which takes into consideration the road disturbance as the uncertainty of system parameters. The design of the robust controller is considered as a dynamic optimisation problem, and two artificial intelligence approaches of genetic algorithm and particle swarm optimization are adopted to find the optimum amounts of weighted mixture of H∞/H2. The cost function of the robust controller is designed based on the norms of the weighted mixture of H∞/H2 for a plant with a definite feedback gain and coefficient of norm of infinity that varies in the range between 0 and 1 representing absolute H2 and H∞, respectively. Particle swarm optimisation showed a competitive convergence to the global minimum of 127 in the shortest time and was selected as the best performing technique. The adopted system improved the system response in terms of sprung mass acceleration, suspension deflection and unsprung mass displacement. The obtained results from the simulations further confirm the superiority of the proposed system relative to the classical passive suspension, and signify the robustness of the active controller design.
Keywords: active suspension; robust control; suspension deflection; particle swarm optimisation.
Special Issue on: Emerging Technologies for Traffic and Transportation Science
Optimal design of die casting process parameters of A713 cast alloy with grain refinement by using a genetic algorithm approach for automobile industries
by Rosang Pongen, Anil Kumar Birru, Parthiban P
Abstract: Aluminium die castings cover a major domain in the field of production, which mainly involves automobile and aerospace areas, owing to its high strength to weight ratio and the high industrial demand for aluminium alloys. Aluminium die castings are associated with many casting defects, which are influenced by many process parameters and influence the final mechanical properties of the die cast aluminium alloy. The density, which gives an idea about the variation of porosity of the die cast parts, is considered to play a vital role in the quality of the alloy. Since die casting is governed by many process parameters and often results in castings with poor properties, it is necessary to know the nature of the output responses before manufacturing. A genetic algorithm (GA) optimal prediction model may help in predicting the optimal output responses before the actual production in die casting. In this present research, a GA approach for optimising the theoretical and experimental density of an A713 alloy with Al-3.5 Ti-1.5C and Al-3Cobalt as grain refiners is carried out. The selected die casting process parameters are molten metal temperature, Al-3.5, Ti-1.5C, and Al-3Cobalt (wt. %), die temperature and injection pressure. Theoretical and experimental densities are considered as outputs for the GA modelling. The GA was run for two cases, one case for theoretical density optimal prediction modelling and other case for experimental density optimal prediction modelling. The model for optimally predicting the theoretical and experimental density of A713 alloy with grain refiners has been established using the GA.
Keywords: A713 alloy; die casting; optimisation; genetic algorithm; experimental density; theoretical density.
Special Issue on: Recent Trends and Advancements in Marine Transportation Electrification
Robust speed control of induction motor drive for electric traction application
by Usha Sengamalai, Geetha Anbazhagan, Thamizh Thentral T M, Boopathi C S
Abstract: The proposed system focuses on improving the speed performance of traction drive by implementing the robust fuzzy logic controller-based inverter fed parallel connected induction motors. The fuzzy controller is compared with a conventional controller. The performance of the modified induction motor drive for traction is analysed and improved under parameter variations to achieve robust speed control. The simulation and hardware results are realised for the proposed system and compared with the conventional system.
Keywords: asynchronous motor; robust speed control; PI controller; Fuzzy controller; Parameter variations.