Search Results (29)

This paper studies the scheduling of just-in-time part delivery for a mixed-model assembly line with material supermarkets under an unfixed path. According to the problem description and related assumptions, a mixed-integer programming model with the goal of minimizing the line-side inventory and delivery energy consumption of automated guided vehicles (AGVs) was constructed. Based on the material demand calculated according to the assembly plan, the model decides the parts to be delivered, the schedule of each delivery round, and the route of the AGV trolley. For small-scale problems, the epsilon constraint method is used to solve the Pareto frontier accurately. For large-scale problems, an improved version of the NSGA-II (Non-dominated Sorting Genetic Algorithm II) is designed to solve the problem more efficiently. Numerical analyses of different scales demonstrated the efficiency of the proposed algorithm. Furthermore, a sensitivity analysis showed that using a smaller AGV capacity with more frequent delivery can achieve a lower inventory level but higher energy consumption. Therefore, enterprises need to choose reasonable delivery schemes according to the assembly line layout and station occupation to save assembly space and achieve the target of carbon emissions reduction. Full article

Urban public transport companies worldwide are introducing environmentally friendly bus solutions, and in cities with an existing trolleybus network, battery-assisted trolleybuses are an efficient alternative. Equipped with a traction battery, these vehicles allow a short range outside of the trolley lines and on-board recuperation, and they combine the advantages of electric buses and trolleybuses without the need for costly infrastructure expansions. Two similar battery-assisted trolleybuses are in operation in Žilina, where the unitary traction energy consumption has been observed to decrease as a function of the battery-powered and on-trolley-line vehicle run ratio. This theory was confirmed by statistical regression analysis of real operational data for one year of operation in different situations. This research also includes an analysis of battery-assisted trolleybuses’ operation on conventional trolleybus lines, which brought surprising findings, as well as an analysis of other selected indicators that can be dependent on the battery run ratio. These findings can contribute to reducing traction energy consumption by simply modifying the operating technologies without the need for extensive investment in infrastructure or vehicle equipment. This research is pilot research ready for in-depth research. Full article

The high-speed railway project and the ultra-high-voltage transmission project represent two crucial components of China’s “new infrastructure”. As the construction of these two projects progresses rapidly, it is inevitable that instances of intersections will occur. Extreme conditions may cause damage to ultra-high voltage transmission cables. When a high-speed train passes by an ultra-high voltage transmission line, it poses a serious safety hazard. To address this issue, engineering examples were utilized to examine the protection structure scheme, protection distance, protection load, and construction procedures when a high-speed railway intersects a 1000 KV ultra-high voltage transmission line. A shed structure form and construction method for the electric power protection were proposed to ensure the safe operation of the high-speed railway while also achieving the safe and rapid construction of the high-speed railway protection structure in the safety zone of the approaching 1000 kV ultra-high voltage transmission line. The results indicated that the protection of high-speed railway crossings and 1000 kV ultra-high voltage transmission lines primarily focuses on line-break protection. The concrete shed structure with a straight wall and a flat roof was designed to meet the requirements of high-speed railway crossings. The line-break protection method enables the construction of an automatic warning protection corridor and a complete movable trolley quickly and safely within the safety zone near the transmission line. The implementation effect is, therefore, positive. It can be used as a reference point for other projects of a similar nature. Full article

With the emergence of Industry 4.0 in intralogistics, the need for flexible material handling solutions is increasing. While conventional conveyor systems are often too inflexible to meet changing requirements. Automated guided vehicles offer an answer, additional solutions are required for companies relying on already busy and crowded shop floors. This paper presents a concept for a periphery-free electrified monorail system (PEMS) that enables flexible material transport with minimal floor requirements. The PEMS is based on classic electrified monorail technology, and requires no additional peripheral devices within the rail system. Installation and maintenance costs are kept to a minimum through simplified branching elements and a battery-powered energy supply for the vehicles. The modular design of the rail elements further allows transport on standardized Euro-pallets. Moreover, a taxonomy for evaluating the passivity of branching elements of electrified monorail systems is introduced. The functionality of the PEMS was validated by conducting real experiments using a prototype, The results show that the PEMS provides high flexibility in terms of layout design and usage, allowing for fast adaption to the changing requirements of intralogistics. Full article

Mining production, being one of the most energy-intensive industries globally, consumes substantial amounts of fossil fuels and contributes to extensive carbon emissions worldwide. The trend toward electrification and advanced developments in battery technology have shifted attention from diesel power to battery alternatives. These alternatives are appealing, as they contribute to decarbonisation efforts when compared to conventional diesel trucks. This paper presents a comprehensive review of recent technological advancements in powertrains for Mining Haulage Truck (MHT). It also compares these configurations based on mining system-level considerations to assess their future potential. The evaluated configurations include Diesel-Electric Truck (DET), Trolley Assist Truck (TAT), Battery-only Truck (BOT), Battery Trolley with Dynamic charging truck (BT-D), and Battery Trolley with Stationary charging truck (BT-S). According to the analysis, the energy demand for on-board diesel or battery power (excluding trolley power) in these alternative options is as follows: DET—681 kWh, BOT—645 kWh, TAT—511 kWh, BT-S—471 kWh, and BT-D—466 kWh. The paper also illustrates the theory of battery size design based on the current battery technology, battery material selection, battery package design, and battery size selection methods. In the case of tailored battery size selection, BOT, BT-D, and BT-S configurations require LiFePO₄ (LFP) battery masses of 25 tonnes, 18 tonnes, and 18 tonnes, respectively. Based on a techno-economic assessment of battery MHT alternatives with a future perspective, it has been determined that BT-D requires the lowest amount of on-board battery energy. Furthermore, over a span of 20 years, BT-S has demonstrated the lowest on-board battery cost. Full article

The increasing demand for efficient and cost-effective transportation solutions has led to the exploration of unconventional modes of transportation, such as ziplines. This paper presents the development of an electric prototype for a trolley that can be used for the simultaneous transport of goods and people on ziplines. The prototype is designed with a modular system that allows for easy customization based on the cargo’s weight and size. Two lightweight Maxon motors have been integrated for traction purposes with two Maxon inverters and a low-voltage swappable battery pack. The trolley’s chassis is made of lightweight materials, such as aluminum, making it highly maneuverable and capable of traveling at high speeds. The lightweight permits the operators to detach the trolley from the zipline when needed. The prototype’s traction and braking systems are controlled through a user-friendly interface, making it easy to operate, and with the possibility of a robust and automatic routine for goods transport. In this article, we present the simulation for the design and testing of the prototype, as well as its potential applications in various industries, such as mining, agriculture, and emergency services. Our results show that the prototype is a viable solution for zipline-based transportation, with high efficiency and performance standards. Further research and development are being conducted to optimize the prototype’s performance and expand its applications. Full article

Electric transport vehicles offer sustainable transportation solutions with benefits, such as reduced emissions, noise, and operating costs. This paper draws an overview of the available technical solutions to actuate transport vehicles with electric drives, as depicted by patent literature. A dataset of 1784 patents was created; the documents were selected through a systematic approach, and the patents were then classified according to a number of user-defined categories. The dataset was analyzed by applying two different methods: (i) a quantitative analysis (literature overview), enabling glance evaluations about the defined categories, and (ii) a qualitative analysis (detailed analysis), which focuses on the detection of interesting design features or innovative solutions. The results of this work not only provide an alternative and complementary overview to the analysis of solutions that may emerge from a scientific literature review, but can also offer support in strategic planning to companies wishing to protect their innovations and remain competitive in the evolving market of transport vehicles. Full article

The condition monitoring of an overhead contact line (OCL) is investigated by developing an innovative monitoring system for a pantograph on an electrical multiple unit of a regional line. Kinematic and dynamic modelling of the pantograph is conducted to support the designed monitoring system. The modelling is proved through rigorous test-rig experiments, while the proposed methodology is then validated through extensive field tests. The field tests serve a dual purpose: First, to validate the monitoring system using benchmark measurements of the tCat^® trolley, and second, to assess the reproducibility of measurements in a realistic case. This paper presents the OCL monitoring system developed in the framework of the H2020 project SIA. The accuracy of our results is not far from that of other commercial systems, with just 12 mm of absolute error in the height measurement. Therefore, they provide reliable information about trends in various key performance indicators (KPIs) that facilitates the early detection of failures and the diagnosis of anomalies. The results highlight the importance of model calibration and validation in enabling novel health monitoring capabilities for the pantograph. By continuously monitoring the parameters and tracking their degradation trends, our approach allows for optimized scheduling of maintenance tasks for the OCL. Full article

After overcoming COVID-19, the tourism demand around the world is on the rise again. At the same time, the interest in eco-friendliness is growing again, and efforts are being made to build an eco-friendly tourism ecosystem. In this study, assuming that a battery-powered electric city tour bus is adopted instead of an existing internal combustion engine city tour bus, we tried to develop optimal design and operation algorithms for battery-powered electric city tour bus systems. The developed algorithm pursues the maximization of the profit, which is calculated through the ticket price paid by tourists using the city tour bus and the overall cost of the electric city tour bus system. In addition, the decision variables of the algorithm are the daily number and interval of operations of the electric city tour bus, which are related to the tourism demand, the battery capacity of the electric city tour bus, and whether a pantograph-type wireless charger is installed or not at the bus stop. The operations research method is used to develop the design algorithm, and numerical examples are derived as the result of the optimal design to verify the proposed algorithm by referring to the operating situation of the Blue Trolley Line in Oahu, Hawai’i. As a result, it is found that profit maximization can be achieved by changes in the daily number and interval of operations on designated routes. Full article

Truck-Shovel (TS) systems are the most common mining system currently used in large surface mines. They offer high productivity combined with the flexibility to be rapidly relocated and to adjust load/haul capacity and capital expenditure according to market conditions. As the world moves to decarbonise as part of the transition to net zero emission targets, it is relevant to examine options for decarbonising the haulage systems in large surface mines. In-Pit Crushing and Conveying (IPCC) systems offer a smaller environmental footprint regarding emissions, but they are associated with a number of limitations related to high initial capital expenditure, capacity limits, mine planning and inflexibility during mine operation. Among the emerging technological options, innovative Trolley Assist (TA) technology promises to reduce energy consumption for lower carbon footprint mining systems. TA systems have demonstrated outstanding potential for emission reduction from their application cases. Battery and energy recovery technology advancements are shaping the evolution of TAs from diesel-electric truck-based patterns toward purely electrified BT ones. Battery Trolley (BT) systems combined with autonomous battery-electric trucks and Energy Recovery Systems (ERSs) are novel and capable of achieving further significant emission cuts for surface mining operations associated with safety, energy saving and operational improvements. This article reviews and compares electrification alternatives for large surface mines, including IPCC, TA and BT systems. These emerging technologies provide opportunities for mining companies and associated industries to adopt zero-emission solutions and help transition to an intelligent electric mining future. Full article

This paper presents a dedicated system for de-icing trolley wires. The proposed issue is appropriately under the protection of intellectual property for solving as described in patent no.B1 230665 PL in the Patent Office of the Republic of Poland. In the solution presented herein, de-icing is achieved mainly by electrodynamic force excitation and secondarily as a result of heating. Because ice is removed primarily through vibrations, it avoids a large consumption of electricity associated with the high specific heat of water. More importantly, operation is nearly simultaneously applied to the total distance of the trolley power grid between two substations. For this reason, it requires less electricity consumption and less time to apply than in heating, mechanical, or chemical methods. Full article

This paper mainly studies the exponential stability of the highly nonlinear hybrid neutral stochastic differential equations (NSDEs) with multiple unbounded time-dependent delays and different structures. We prove the existence and uniqueness of the exact global solution of the new stochastic system, and then give several criteria of the exponential stability, including the $q_1$th moment and almost surely exponential stability. Additionally, some numerical examples are given to illustrate the main results. Such systems are widely applied in physics and other fields. For example, a specific case is pantograph dynamics, in which the delay term is a proportional function. These are widely used to determine the motion of a pantograph head on an electric locomotive collecting current from an overhead trolley wire. Compared with the existing works, our results extend the single constant delay of coefficients to multiple unbounded time-dependent delays, which is more general and applicable. Full article

Transport of ore and overburden in open-pit mines is often performed with large haul trucks. Battery-electric operation of haul trucks can significantly reduce the CO${}_2$ emissions and the fossil fuel dependence of open-pit mining. This simulation study investigates the feasibility and economy of operating large haul trucks battery-electrically, charging from an electric road system in the form of overhead trolley lines. The used simulation model is verified against measurements on diesel-electric haul trucks in normal operation. The simulation model is then tested with five drive cycles representing typical operations in the Aitik copper mine in northern Sweden. This simulation study shows that battery-electric operation with an electric road is feasible. It is shown that battery-electric operation is much cheaper than diesel-electric operation under reasonable assumptions. It is also much cheaper than diesel-electric operation assisted by an electric road. Full article

The urban transport system based on trams as the basic means of transport is one of the oldest systems of human transport in urban agglomerations. A tram is a more efficient, cheaper-to-operate, and greener means of transport compared to a bus. Striving to enable the use of this means of transport by elderly and disabled people, constructors and manufacturers of tram vehicles began to consider the requirements of the ordering parties—organizers of municipal public transport—in their solutions. The basic condition for disabled and elderly people to use tram transport is the possibility of safe and efficient entry and exit from the vehicle at tram stops. The fulfillment of this condition is possible only in the case of tram vehicles with a low 100% floor, and this, in turn, requires the replacement of trolleys with traditional wheelsets, that is, trolleys with independently rotating wheels, in the construction of the running gear. A wheelset with independently rotating wheels (IRW) does not have self-centering properties, and, thus, problems may arise with excessive wear of wheel and rail profiles and with continuous contact of the wheel flange with the rail, which may, consequently, lead to derailment. Driving a vehicle on the track in this case is governed by different laws. To prevent such phenomena, it is required to use the wheel drive control system, which allows for the stabilization of the vehicle movement on the track. Both the introduction of independently rotating wheels in the construction of the bogie and the drive connected to the wheel control system requires research and analysis to confirm the correctness of the assumptions made. The innovative solution of the control system in the case of a tram vehicle was patented and then the patent was implemented to produce a low-floor tram with 100% low floor by a Polish tram manufacturer. This article presents the results of the work carried out on the adoption of the concept of a running gear and drive solution for a low-floor tram vehicle with independently rotating wheels and the results of simulation analysis of the drive control of such a system, using mathematical models of the mechanical system (running gear) and the electrical system (motor drive control system). Full article

This article is a continuation of a case study in which we presented the results of research on processes generated under fire conditions by mixing molten ammonium nitrate (AN) with selected polymers. Here, we present an analysis of how certain materials, which may frequently appear in farm buildings and are commonly used in the immediate vicinity of humans, can potentially form explosives. The chosen materials include polyamides (PA) from which the wear-resistant machine elements are made (e.g., high-performance gears, wheels of transport trolleys); polyvinyl chloride (PVC) used, i.e., in construction carpentry, electrical insulation, and hydraulic pipes; polystyrene (PS) used, i.e., in insulation and containers; and poly(methyl methacrylate) (PMMA), i.e., so-called organic glass and plexiglass. The research results showed that these seemingly harmless and safe materials, mixed with AN and heated under fire conditions, may turn into explosives and stimulate stored AN. This creates significant risks of an uncontrolled fire progress. Full article