Search Results (67)

Although critical to modern logistics, heavy-duty commercial vehicles face mounting pressure to improve energy efficiency and reduce emissions. The aim of this study was to evaluate the techno-economic and environmental performance of four vehicle configurations: internal combustion engine (ICE) tractors and battery electric tractors (BETs), each respectively paired with either a conventional or an electrified trailer. To optimize energy utilization while proactively mitigating the longitudinal impact risks that trigger vehicle instability, a coordinated control strategy based on power decoupling and a real-time, efficiency-oriented torque distribution strategy were designed. Simulations under C-WTVC and CHTC-TT cycles revealed that electrified trailers substantially improved the system efficiency. Under fully loaded conditions, BETs paired with electrified trailers reduced the direct energy expenditures by 76.5% compared to conventional ICE vehicles. Notably, compared to pure electric tractors with conventional trailers, the addition of electrified trailers further reduced the energy consumption by 29.1%. Meanwhile, ICE tractors paired with electrified trailers achieved a 35.6% energy cost reduction. Furthermore, a fuel-cycle well-to-wheels (WTW) assessment of the use phase, based on a specified regional grid emission factor, demonstrated that the BETs and hybrid configurations reduced the operational greenhouse gas emissions by 64.9% and 29.3%, respectively, compared to the baseline. These findings indicate that trailer electrification offers consistent economic and environmental benefits under the simulated scenarios, thereby providing a robust theoretical foundation for the low-carbon transition, transportation sustainability, and selection of sustainable technologies in road freight. Full article

Safety is a fundamental issue in autonomous mobile robot design. This paper presents a safety-critical control framework for nonholonomic tractor-trailer vehicles subject to both safety and physical constraints. Control barrier functions (CBFs) are employed to enforce hard safety constraints, generating a safe set that ensures obstacle avoidance. These CBFs are integrated with control Lyapunov functions (CLFs) to enable trajectory tracking while maintaining safety. To reduce conflicts between CBFs and CLFs and improve obstacle avoidance performance, we optimize their decay rates. Leveraging the concept of differential flatness, we design a controller that enables the system to follow the desired safe trajectory. Finally, the effectiveness and performance of the proposed method are demonstrated through numerical simulations and real-world experiments. Full article

The dispatch planning process plays a central role in liquid transportation, where the accurate selection of trailers, ISO tanks, vehicles, and drivers determines the effectiveness, safety, and cost structure of operations. Each resource has its own technical, regulatory, and operational characteristics, and these characteristics must align with product specifications, transportation routes, loading and delivery conditions, and the current state of the fleet. The breadth of these parameters makes resource selection a highly complex task for planners, especially in environments where rapid decision-making is needed to address changing demands. This study presents a rule-based expert system designed to capture the decision-making logic of experienced professionals and apply it consistently during dispatch planning. The system incorporates 28 decision rules formulated from the collective knowledge of experts working in liquid logistics operations, including planners, industrial engineers, and senior managers. These rules enable the system to evaluate multiple resource combinations and recommend the most suitable allocation for each order. The expert system was evaluated using real operational data obtained from a leading logistics company in Turkey. Comparative results indicate that the system provides more cost-effective, efficient, and balanced dispatch plans than manual planning conducted by an experienced human planner. The system not only improves resource utilization but also reduces planning errors and variations arising from human judgment. Overall, the findings demonstrate that a rule-based expert system can serve as a reliable and scalable decision-support tool for complex dispatch planning problems in liquid transportation, offering consistent performance across different operational scenarios. Full article

Reverse parking maneuvering of a vehicle with a trailer system is a difficult task to complete for human drivers due to the multi-body nature of the system and the unintuitive controls required to orientate the trailer properly. The problem is complicated with the presence of other vehicles that the trailer and its connected vehicle must avoid during the reverse parking maneuver. While path-planning methods in reverse motion for vehicles with trailers exist, there is a lack of results that also offer collision avoidance as part of the algorithm. This paper hence proposes a modified Hybrid A*-based algorithm that can accommodate the vehicle–trailer system as well as collision avoidance considerations with the other vehicles and obstacles in the parking environment. One of the novelties of this proposed approach is its adaptability to the vehicle with trailer system, where limits of usable steering input that prevent the occurrence of jackknife incidents vary with respect to system configuration. The other contribution is the addition of the collision avoidance functionality which the standard Hybrid A* algorithm lacks. The method is developed and presented first, followed by simulation case studies to demonstrate the efficacy of the proposed approach. Full article

The infield transport of harvested sugarcane stalks (transshipment operation) during mechanized harvesting is widely recognized as the operation with the greatest potential to induce soil compaction. Nevertheless, there is still a lack of experimental data on the effect of compaction resulting from transshipment vehicles on soil physical functionality. We assessed the effects of realistic infield traffic from different transshipment configurations on soil structural and functional properties and their effects on crop yield. Three transshipment systems under controlled traffic farming system were evaluated: a tractor pulling one four-axle trailer unit with 21 Mg carrying capacity (1T/21), a tractor pulling two axle trailer units with 10 Mg carrying capacity (2T/10), and an autonomous truck with four axles and one trailer with 20 Mg carrying capacity (1TT/20). Several analyses were conducted, including degree of compaction (DC), macroporosity (MaP), air-filled porosity (ε_a10), soil air permeability (k_a10), and saturated hydraulic conductivity (Ks). Soil samplings were performed in surface and subsurface layers of an Oxisol in southeastern Brazil at the planting row and inter-row, and at the midpoint between these positions, over two consecutive sugarcane harvests. Although machine traffic occurred at low soil water content, all transshipment configurations promoted soil compaction during the first harvest, with the greatest changes in soil physical attributes in the 0–10 and 10–20 cm layers in the inter-row center and, in some cases, at the midpoint. However, all treatments preserved soil conditions in the planting row. The 1TT/20 transshipment induced the greatest compaction, with significant effects on DC, MaP, and ε_a10 in the inter-row and midpoint positions. Despite structural alterations, no significant differences were observed among treatments for k_a10 and Ks. However, after the first harvest, k_a10 frequently reached critical thresholds of low permeability in trafficked areas, indicating functional degradation of soil aeration. Sugarcane yield was not affected by the transshipment configurations. The absence of productivity differences reflects the effectiveness of controlled traffic in confining compaction to the inter-row center and midpoint while preserving the planting row. Although short-term yield was not affected, structural degradation in trafficked areas and the persistence of high subsoil compaction indicate the potential for cumulative long-term impacts. Continuous monitoring and integrated soil management strategies remain essential to mitigate progressive compaction under mechanized sugarcane harvesting. Full article

Articulated vehicles are essential for global freight transportation but are highly susceptible to instability phenomena such as jackknifing, trailer sway, and rollover, particularly under high-speed or emergency maneuvers. These challenges become even more critical in the context of autonomous driving, where stability must be guaranteed without human intervention. Conventional systems like Electronic Stability Control (ESC) and Roll Stability Control (RSC) provide reactive interventions but lack predictive capability, while other advanced methods often address isolated objectives. To overcome these limitations, this paper proposes a Model Predictive Control (MPC)-based control strategy that integrates trajectory tracking, yaw stability, and longitudinal speed regulation within a unified optimization framework, using differential braking as the primary actuator. A dynamic model of a tractor–semitrailer combination was developed, and the proposed controller was validated through high-fidelity simulations under varying operating conditions, including speeds exceeding the critical threshold of 31.04 m/s. Results demonstrate that the MPC-based system effectively mitigates instability, reduces articulation angle and yaw rate deviations, and maintains accurate path tracking while proactively managing vehicle speed. These findings highlight MPC’s potential as a cornerstone technology for safe and reliable autonomous operation of articulated vehicles. Future work will focus on experimental validation and multi-actuator coordination to further enhance performance. Full article

A promising approach to advancing sustainable urban mobility is the increased use of light electric vehicles, such as e-cycles and their cargo-carrying variants: e-cargo cycles. These micromobility vehicles fall between e-cycles and conventional vehicles in terms of transport capacity, range, and cost. A key advantage of e-cargo cycles over their non-electrified counterparts is the electric powertrain, which enables them to carry heavier payloads, travel longer distances, and reduce driver fatigue. Since the primary use of e-cargo cycles is urban parchment deliveries, trip efficiency plays a critical role in their effectiveness within urban logistics. This efficiency is influenced by factors such as travel distance, traffic density, and the weight and volume of the delivery payload. While higher delivery capacity generally enhances efficiency, studies have shown that as the drop size increases, the efficiency of e-cargo cycle delivery trips tends to decline. A practical way to address this limitation is the use of cargo attachments, such as trailers. These micromobility solutions are already widely implemented globally and significantly enhance transport capacity. This paper reports the process of designing and testing the control algorithm of an electrical system for an experimental attachment demonstrator that can be used to convert most cycle vehicles into cargo variants. The system integrates two 250 W BLDC hub motors, two 576 Wh lithium-ion batteries, dual load-cell sensing in the coupling element, and an STM32-based controller to provide independent propulsion and synchronization with the leading cycle. The force-based control strategy enables automatic adaptation to varying payloads typically encountered in urban logistics, which is supported by the variable storage volume capable of transporting payloads of up to 200 kg. Full article

Current research on the performance and emissions of vehicles and internal combustion engines should include analysis of efficiency-enhancing technologies and emission reduction strategies across a variety of vehicle systems. To improve both performance and emission control, it is necessary to examine advanced heavy-duty driveline technologies, considering their real-world impact on fuel economy and emission reduction under various driving conditions. This article will deal with predictive cruise control (PCC) and its influence on the operating characteristics of a truck, specifically a semi-trailer combination. The measurement was carried out using dynamic driving tests of a truck on a selected road. The use of electronic systems for automatically maintaining the vehicle’s motion states (especially speed) based on the specified conditions most often has several benefits for the driver not only from the point of view of vehicle operation but also from the point of view of transport companies (cost reduction). It is generally known that the use of these electronic systems reduces the vehicle’s fuel consumption and therefore also reduces the amount of exhaust gases. Comparing the individual directions of the road tests, the difference in relative maximum power utilization between the driver and the PCC system was 26.42% in the ST-MY direction and 23.81% in the MY-ST direction. The use of PCC also results in fuel savings of up to 17.11%. This study provides new insights into the quantification of the impact of PCC on fuel consumption in real operating conditions and highlights the potential for integrating PCC into driver assistance systems and logistics planning to reduce costs and emissions in freight transport. Further research could focus on applying this system in specific road conditions. Full article

In vehicle routing problems, long-distance transportation poses a significant challenge to the optimization of transportation costs while adhering to regulations. This study investigates a special type of logistics problem that focuses on liquid transportation systems involving full truckload delivery and the rest–break–drive periods of truck drivers over long distances according to the regulations of the United States. Based on an exact solution algorithm, this work combines a long-distance full truckload fluid transportation problem with the concept of truck driver schedules for the first time. The goal is to optimize transportation expenses while managing challenges related to the rest–break–drive periods of truck drivers, time windows, trailer varieties, customer segments, food and non-food products, a diverse fleet, starting locations, and the diverse tasks of vehicles. In order to reach optimality, a construction heuristic and the column generation method were employed, supplemented by several acceleration strategies. Performance analysis, carried out with artificial input sets mirroring real-life scenarios, indicates that low optimality gaps can be obtained in an appropriate amount of time for large-scale long-haul liquid transportation. Full article

In line with EU decarbonization targets for the heavy-duty transport sector, this study proposes an analytical methodology to assess the impact of diesel performance additives on fuel consumption in Euro 6 heavy-duty vehicles, the prevailing standard in the circulating European road tractor fleet. A fleet of five N3-category road tractors equipped with tanker semi-trailers was monitored over two phases. During the first 10-month baseline phase, the vehicles operated with standard EN 590 diesel (containing 6–7% FAME); in the second phase, they used a commercially available premium diesel containing performance-enhancing additives. Fuel consumption and route data were collected using a GPS-based system interfaced with the engine control unit via the OBD port and integrated with the fleet tracking platform. After applying data filtering to exclude low-quality or non-representative trips, a 1% reduction in fuel consumption was observed with the use of fuel with additives. Route-level analysis revealed higher savings (up to 5.1%) in high-load operating conditions, while most trips showed improvements between −1.6% and −3.4%. Temporal analysis confirmed the general trend across varying vehicle usage patterns. Aggregated fleet-level data proved to be the most robust approach to mitigate statistical variability. To evaluate the potential impact at scale, a European scenario was developed: a 1% reduction in fuel consumption across the 6.75 million heavy-duty vehicles in the EU could yield annual savings of 2 billion liters of diesel and avoid approximately 6 million tons of CO₂ emissions. Even partial adoption could lead to meaningful environmental benefits. Alongside emissions reductions, fuel additives also offer economic value by lowering operating costs, improving engine efficiency, and reducing maintenance needs. Full article

Light-duty trucks (LDTs) are often used to tow trailers. Towing increases the load on the engine, and this additional load can affect exhaust emissions. Although heavy-duty towing impacts are widely studied, data on LDT towing impacts is sparse. In this study, portable emissions measurement systems (PEMSs) were used to measure in-use emissions from three common LDTs during towing and non-towing operations. Emission rates were characterized by operating modes defined in the Environmental Protection Agency’s (EPA’s) MOVES (MOtor Vehicle Emissions Simulator) model. The measured emission rates were compared to the default rates used by MOVES, revealing similar overall trends. However, discrepancies between measured rates and MOVES predictions, especially at high speed and high operating modes, indicate a need for refinement in emissions modeling for LDTs under towing operations. Results highlight a general trend of increased CO₂, CO, HC, and NOx when towing a trailer compared to non-towing operations across nearly all operating modes, with distinct CO and HC increases in the higher operating modes. Although emissions were observed to be notably higher in a handful of scenarios, results also indicate that three similar LDTs can have distinctly different emission profiles. Full article

The control of vehicles towing trailers is of significant interest to industry due to their wide-ranging applications across various sectors. Trailers play essential roles in logistics, mining, and other fields. This study focuses on the control of a dumper with a trailer specifically used for the monitoring of terrain stability in mining operations. The trailer is equipped with a radar system for detecting potential ground shifts that could jeopardize fieldwork safety. While numerous studies have addressed the control of Ackerman vehicles and trailers, this dumper presents a unique challenge due to its rear-axle steering mechanism. Due to this configuration, which has not been extensively studied in the literature, although the differential flatness of the system is proven, computation of the flat outputs leads to a system of partial differential equations that cannot be solved analytically. For this reason, this paper examines partial feedback linearization to facilitate control and proposes a solution for trajectory tracking that also stabilizes jack-knifing tendencies between the vehicle and trailer. The designed control system was successfully validated in a virtual environment. Full article

Agricultural tractors are equipped with air braking systems to supply and control the braking systems of towed vehicles. This system’s functional and operational characteristics significantly impact the compatibility and speed of the braking system of the tractor–trailer combination and are therefore checked during approval tests. This paper presents a test methodology and a description of the instrumentation and apparatus used to test the air braking systems of tractors under stationary conditions, as required by EU Regulation 2015/68. Sample test results of the trailer air supply system are included, such as checking the system for leaks, checking the pressure at the coupling heads, checking the compressor flow rate and air reservoir capacity, and checking the response time of the tractor control line. Approval authorities and tractor manufacturers can use the work results for quality control or product qualification tests. Full article

Path planning for intelligent semi-trailers encounters numerous challenges in complex traffic conditions. Serious consequences, such as vehicle rollover, may occur when the traffic conditions change. Therefore, it is vital to consider both the surrounding dynamic traffic conditions and the vehicle’s roll stability during the lane-changing process of intelligent semi-trailers. We propose an innovative path-planning method tailored for intelligent semi-trailers. This path-planning method is designed for semi-trailers on straight-road alignments. Firstly, we employ a fuzzy inference system to process information about surrounding traffic, make lane-changing decisions, and determine the starting point. Secondly, the lane-changing path is generated using a B-spline curve. Subsequently, we apply a particle swarm optimization algorithm to enhance the B-spline curve. Thirdly, we utilize a Transformer model to analyze the nonlinear relationships among information about surrounding traffic, vehicle information, and the roll stability of the intelligent semi-trailer. We establish the roll stability boundary for the vehicle. Finally, we design a multi-objective cost function to select the optimal path. The simulation results demonstrate that the proposed method dynamically adapts the planned path to variations in driving parameters, ensuring trackability while reducing the steering angle, lateral acceleration, and yaw rate. This approach meets the roll stability requirements of intelligent semi-trailers, significantly enhances their stability during lane changing, and provides robust support for safe and efficient operation. Full article

When a railway train runs along a curved track with braking, the dynamic behaviors of the vehicle are extremely complex and difficult to accurately reveal due to the coupling effects between the wheel–rail interactions and the disc–pad frictions. Therefore, a rigid–flexible coupled trailer car dynamics model of a railway train is established. In this model, the brake systems and vehicle system are dynamically coupled via the frictions within the braking interface, wheel–rail relationships and suspension systems. Furthermore, the effectiveness of the established model is validated by a comparison with the field test data. Based on this, the dynamic response characteristics of vehicle under curve and straight braking conditions are analyzed and compared, and the influence of the curve geometric parameters on vehicle vibration and operation safety is explored. The results show that braking on a curve track directly affects the vibration characteristics of the vehicle and reduces its operation safety. When the vehicle is braking on a curve track, the lateral vibration of the bogie frame significantly increases compared to the vehicle braking on a straight track, and the vibration intensifies as the curve radius decreases. When the curved track maintains equilibrium superelevation, the differences in primary suspension force, wheel–rail vertical force, and wheel axle lateral force between the inner and outer sides of the first and second wheelsets are relatively minor under both straight and curved braking conditions. Additionally, under these circumstances, the derailment coefficient is minimized. However, when the curve radius is 7000 m, with a superelevation of 40 mm, the maximum dynamic wheel load reduction rate of the inner wheel of the second wheelset is 0.54, which reaches 90% of the allowable limit value of 0.6 for the safety index, and impacts the vehicle running safety. Therefore, it is necessary to focus on the operation safety of railway trains when braking on curved tracks. Full article