Truck Operations Research Articles

Comparative Study of Electrically Excited Conventional and Homopolar Synchronous Motors for the Traction Drive of a Mining Dump Truck Operating in a Wide Speed Range in Field-Weakening Region

A synchronous homopolar motor (SHM) has a salient pole passive rotor, an excitation winding located on the stator, and no permanent magnets, which ensures high reliability and makes this type of motor a good alternative to motors traditionally used in traction drives. However, there is no comparison between SHMs and conventional brushed synchronous machines for traction applications in the literature. In this paper, the performances of a wound rotor synchronous machine (WRSM) and SHM are theoretically compared at the operating points of a 370 kW dump mining truck drive traction curve that has a 10:1 constant power range in the field weakening region. The nine-phase motors under comparison have the same outer diameter of the stator lamination. Before comparison, both motor designs are optimized using the Nelder–Mead method to minimize the semiconductor inverter rated current and the operating cycle power loss. The main advantages of the WRSM, which was designed, are reduction in stator length, smaller losses, and smaller inverter. The reduction in the total stator length was by 1.23 times taking into account the winding end parts as well. Losses were reduced by 1.21 times for the same radius of the stator lamination. Finally, the cost of power modules of the inverter was decreased by 1.4 times. SHM is more reliable since its rotor does not have an excitation winding and a diode rectifier, as in a WRSM with a brushless exciter. In addition, SHM provides lower consumption of copper, which reduces the total mass and cost of active materials. This article also introduces a new term, “inverter utilization factor”, which can be useful, more informative than motor power factor, when comparing traction drives with different types of motors.

A Robust Possibilistic Programming Approach for a Road-Rail Intermodal Routing Problem with Multiple Time Windows and Truck Operations Optimization under Carbon Cap-and-Trade Policy and Uncertainty

This study investigates a road-rail intermodal routing problem in a hub-and-spoke network. Carbon cap-and-trade policy is accommodated with the routing to reduce carbon dioxide emissions. Multiple time windows are employed to enhance customer flexibility and achieve on-time pickup and delivery services. Road service flexibility and resulting truck operations optimization are explored by combining truck departure time planning under traffic restrictions and speed optimization with the routing. To enhance the feasibility and optimality of the problem optimization, the routing problem is formulated in a fuzzy environment where capacity and carbon trading price rate are trapezoidal fuzzy parameters. Based on the customer-centric objective setting, a fuzzy nonlinear optimization model and its linear reformation are given to formulate the proposed routing problem that combines distribution route design, time window selection and truck operations optimization. A robust possibilistic programming approach is developed to optimize the routing problem by obtaining its robust solutions. A case study is presented to demonstrate the feasibility of the proposed approaches. The results show that the multiple time windows and truck operations optimization can lower the total costs, enhance the optimality robustness and reduce carbon dioxide emissions of the routing optimization. The sensitivity analysis finds that increasing the lower bound of the confidence level in the robust possibilistic programming model improve the robustness and environmental sustainability; however, worsen the economy of the routing optimization.

Examination of engine oil condition of dump trucks in open pit mines in the Republic of Armenia

The mining industry of the Republic of Armenia makes an important contribution to the country’s economy, developing rapidly and providing up to 33 % of the share of the raw materials sector. In order to enhance performance and productivity of mining companies in the Republic of Armenia, it is necessary to increase operating efficiency of process equipment and, first of all, of heavy-duty dump trucks, in particular, the BELAZ family. It should be noted that the considerable maintenance and repair burden raises specific demands for the reliability and operability of systems, components and aggregates of dump trucks, in particular, internal combustion engines. The studies have found that the downtime of BELAZ dump trucks because of engine malfunctions accounts for 29 % of the total balance of downtime, which directly leads to the increased operating costs and reduced productivity. The power units of dump trucks have no backup, and, as a result, failure of a unit or a few units will lead to failure of the car as a whole. Power units have closed lubrication systems, failures of which account for a significant share in the total balance of failures of motor vehicles—from 38 to 48 %. In this regard, it is advisable to have information about technical condition of the machine from such source as the lubricating oil. Based on such information from the spectral analysis of the worked oil, it is possible to identify the most unreliable element of the system and perform the entire range of maintenance and repair that allows effective control over technical condition of the car. In order to determine the worked oil characteristics, engine oil of 11 BELAZ dump truck, having different operational life lengths, were subjected to the spectral analysis. The research proved high performance characteristics of engine oil G-Profit MSI Plus SAE 15W-40 API Ci-4/SL and confirmed its application advisability in operation of dump trucks in open pit mines in Armenia.

Do voluntary environmental programs matter? Evidence from the EPA SmartWay program

AbstractThere is mixed evidence on the effectiveness of voluntary environmental programs. We evaluate a voluntary program aimed at reducing transportation emissions, that is, the U.S. EPA SmartWay Program. We construct a novel database of the physical assets used by firms before and after they joined SmartWay and compare changes in the age of their assets with that of firms that did not join SmartWay. Our results show that firms that participated in SmartWay operate substantially newer (i.e., cleaner) trucks compared with non‐SmartWay participants, indicating that SmartWay participation is a credible signal of a firm's reduced emissions footprint emanating from truck operations. After the start of SmartWay, firms that joined invested in newer trucks relative to firms that did not, with about a year reduction in average truck age several years after the program began. SmartWay had a larger effect on firms that own their trucks compared with firms that outsource ownership, and sustained participation increased the program's effectiveness. We estimate that the SmartWay Program has reduced commercial transportation emissions from operations by 25.2 million metric tons of CO2 by increasing the incentive to invest in newer, cleaner trucks. Our study provides insight into factors that make voluntary environmental programs effective.

Solving the number of cross-dock open doors optimization problem by combination of NSGA-II and multi-objective simulated annealing

Chain stores use cross-dock to deliver goods to their branches by outbound trucks. Considering that the total demand of each branch is less than the truck capacity, a vehicle routing problem (VRP) is employed for the cross-dock. Although the number of cross-dock doors is constant, that of open outbound doors can affect the cross-dock performance. In this paper, new multi-objective scheduling and VRP is presented for cross-dock that simultaneously determines the routing, sequencing, and scheduling of the unloading operation of outbound trucks and the number of outbound open doors. Given that there is an NP-hard problem, four metaheuristic algorithms are proposed, and non-dominated sorting genetic algorithm-II and multi-objective simulated annealing are combined in two ways to solve the problem.

Decentralized coordination for truck platooning

AbstractCoordination for truck platooning refers to the active formation of a group of heavy‐duty vehicles traveling at close spacing to reduce the overall truck operations costs. Conventionally, this coordination is achieved by optimizing various truck‐related parameters, such as schedules, velocities, and routes, based on an objective function that minimizes a certain cost, for example, fuel usage. However, prevalent algorithms for the coordination problem are typically integer‐constrained, which are not only hard to solve but are not readily scalable to increasing fleet sizes and networks. In this paper, to overcome these limitations, we propose a centralized formulation to optimize the truck parameters and solve a multidimensional objective cost function including fuel, operation time costs and preferential penalty. Furthermore, to improve the scalability of our proposed approach, we propose a decentralized algorithm for the platoon coordination problem involving multiple fleets and objectives. We perform both theoretical and numerical studies to evaluate the performance of our decentralized algorithm against the centralized solution. Our analysis indicates that the computation time of the proposed decentralized algorithms is invariant to the increasing fleet size, at the cost of a small relative gap to the optimum cost given by the centralized method. We discuss these results and present future directions for research.

Developing Statewide Safety Performance Functions for Commercial Trucks Transporting Hazardous Materials on Interstate Rural Roads in Wyoming

Truck crashes in Wyoming are considered a major issue. Nearly 26% of crashes on rural interstate roads involve hazardous materials (HAZMAT) trucks. Wyoming has a high rate of activities related to the energy industry, as it is considered among the top energy producing states in the U.S.A., and mainly relies on the trucking industry for transportation. A crash involving a HAZMAT shipment might have a catastrophic impact because of the nature of the HAZMAT shipment. Therefore, it is crucial to identify the traffic safety performance of HAZMAT trucks, so suitable countermeasures can be identified to reduce the frequency and severity of these crashes. This study aims to develop safety performance functions (SPFs) for crashes involving HAZMAT utilizing traditional negative binomial (NB) models, as well as variations of the NB model, namely, NB-1 and NB-P. The results indicate that HAZMAT truck crashes are associated with vehicle miles traveled, truck percentage, horizontal and vertical characteristics of road geometry, pavement type, and speed limit. The findings from this study show that the NB-P models outperformed the traditional NB models based on likelihood ratio tests, information criteria, and prediction measures. Relevant insights are made on traditional countermeasures, such as road geometry, warning signs, slippery road surface warnings, and climbing lanes, as well as non-traditional countermeasures including updating variable speed limit (VSL) algorithms, adding variable message signs, and integrating roadway geometry information into connected vehicle applications in Wyoming. These could be considered to assist stakeholders and emergency management agencies in better decision making toward safer operations of HAZMAT trucks.

Drive-Cycle Simulations of Battery-Electric Large Haul Trucks for Open-Pit Mining with Electric Roads

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 CO2 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.

Simultaneous Allocation and Scheduling of Quay Cranes, Yard Cranes, and Trucks in Dynamical Integrated Container Terminal Operations

We present a dynamical modeling of integrated (end-to-end) container terminal operations using finite state machine (FSM) framework where each state machine is represented by a discrete-event system (DES) formulation. The hybrid model incorporates the operations of quay cranes (QC), internal trucks (IT), and yard cranes (YC) and also the selection of storage positions in container yard (CY) and vessel bays. The QC and YC are connected by the IT in our models. As opposed to the commonly adapted modeling in container terminal operations, in which the entire information/inputs to the systems are known for a defined planning horizon, in this research we use real-time trucks, crane, and container storage operations information, which are always updated as the time evolves. The dynamical model shows that the predicted state variables closely follow the actual field data from a container terminal in Tanjung Priuk, Jakarta, Indonesia. Subsequently, using the integrated container terminal hybrid model, we proposed a model predictive algorithm (MPA) to obtain the near-optimal solution of the integrated terminal operations problem, namely the simultaneous allocation and scheduling of QC, IT, and YC, as well as selecting the storage location for the inbound and outbound containers in the CY and vessel. The numerical experiment based on the extensive Monte Carlo simulation and real dataset show that the MPA outperforms by 3-6% both of the policies currently implemented by the terminal operator and the state-of-the-art method from the current literature.

Collaborative truck multi-drone routing and scheduling problem: Package delivery with flexible launch and recovery sites

This paper deals with the problem of coordinating a truck and multiple heterogeneous unmanned aerial vehicles (UAVs or drones) for last-mile package deliveries. Existing literature on truck–drone tandems predominantly restricts the UAV launch and recovery operations (LARO) to customer locations. Such a constrained setting may not be able to fully exploit the capability of drones. Moreover, this assumption may not accurately reflect the actual delivery operations. In this research, we address these gaps and introduce a new variant of truck–drone tandem that allows the truck to stop at non-customer locations (referred to as flexible sites) for drone LARO. The proposed variant also accounts for three key decisions — (i) assignment of each customer location to a vehicle, (ii) routing of truck and UAVs, and (iii) scheduling drone LARO and truck operator activities at each stop, which are always not simultaneously considered in the literature. A mixed integer linear programming model is formulated to jointly optimize the three decisions with the objective of minimizing the delivery completion time (or makespan). To handle large problem instances, we develop an optimization-enabled two-phase search algorithm by hybridizing simulated annealing and variable neighborhood search. Numerical analysis demonstrates substantial improvement in delivery efficiency of using flexible sites for LARO as opposed to the existing approach of restricting truck stop locations. Finally, several insights on drone utilization and flexible site selection are provided based on our findings.

Dynamic Appointment Rescheduling of Trucks under Uncertainty of Arrival Time

The uncertainty of the arrival time of trucks has increased the complexity of terminal operations. The truck appointment system (TAS) cannot respond to this problem in time, which can easily cause appointment invalidation and reduce the efficiency of truck operations and terminal operations. This paper comprehensively considers the related constraints of truck re-scheduling costs, gate waiting costs, and idle emission costs. With the goal of minimizing the comprehensive operating costs of truck companies and port companies, a dynamic appointment rescheduling model for external trucks based on mixed integer nonlinear programming is established. This paper designs an adaptive quantum revolving door update mechanism and proposes a double-chain real quantum genetic algorithm. The simulation experiment results show that compared with the traditional scheduling, the truck dynamic appointment rescheduling model can effectively reduce the comprehensive operating costs of the truck company and the port company and alleviate the congestion of the port. The probability that the truck cannot arrive at the port on time, the advance time for the truck to confirm the arrival time, and the length of time that the external truck cannot arrive at the port on time have a significant impact on the cost of the reschedule of the TAS. This paper favorably supports the manager’s operational decision-making.

Modernization of electromechanical transmission for dump trucks based on long-term operation data

In open pit mining, overburden and mineral haulage is carried out mostly by dump trucks. The number of high-capacity machines persistently grows. Such dump trucks mainly use electromechanical transmission systems. As a rule, dump trucks operate all day and all year round, with idle time for scheduled maintenance. The climatic service conditions assume variations in temperature, humidity and atmospheric pressure in wide ranges during a year, moreover, these physical quantities can fluctuate violently within a short time, for instance, within a day. The road conditions – road grade, hardness, roughness, length, altitude difference – differ greatly per open pit mines. Furthermore, air dustiness, including current-conducting coal- or metal-bearing dust should be taken into account. On the whole, these numerous and diverse factors are impossible to embrace in full at the stages of machine engineering and testing. Thus, during operation, it is necessary to accumulate and analyze the hand-on experience, and to improve all components of electromechanical transmission. This article gives data on four-year operation of BelAZ dump trucks with capacity of 90 and 240 t equipped with electromechanical transmission in open pit coal and ore mines. The traction electrical equipment faults are generalized, their causes are revealed, design modifications are described, as well as the processes of manufacturing and testing and the algorithm of diagnosis are reported. The low count of faults during operation and the high availability factor of the dump trucks equipped with electromechanical transmissions manufactured by RUSELPROM is reflective of the proficiency and competency of the machine engineering, design and testing. The modifications introduced into the electromechanical transmissions are mostly aimed at cost reduction and performance buildup, i.e. at competitive recovery of the product. The obtained results are used in engineering of traction electric equipment set for dump trucks of higher capacity (136, 180, 360 t).

Optimal simulation and experimental research on the operation system of dumper of the stemming production line

Abstract In order to further improve the running speed and stability of the feed truck in the mud production line, optimization simulation and experimental research on the running system of the feed truck were carried out. First, based on the analysis of the operating system of the material truck, Then, according to the experimental plan, an optimization experiment on the project site was carried out, and it was confirmed in a quantitative form that the operating efficiency and stability of the optimized truck operating system have been significantly improved. Finally, the experimental results are applied and analyzed, and a mathematical model that can be used in actual engineering is obtained, so as to reflect the actual engineering application value.

Обоснование оптимального уклона крутонаклонных автосъездов для полноприводных автосамосвалов, эксплуатируемых при доработке алмазорудных месторождений

At present, the design depth of open-cast diamond (kimberlite) mines is increasing through introduction of advanced technologies and new mining and transportation equipment. In 2008-2012 the Yakutniproalmaz Institute and the Institute of Mining developed scientific and methodological principles and design solutions for development of the Udachny and Botuobinsky deep open pit mines using steeply inclined ramps and the CAT-740B articulated dump trucks with the capacity of 39.5 tons. Research was conducted to determine the rational slope for articulated dump trucks in the Udachny open pit and to develop guidelines for safe operation of such dump trucks on steep inclines. The performed experiments demonstrated the ability of articulated dump trucks to safely haul rocks with loads that were close to the nominal capacity using ramps with the slope gradients up to 24% in various weather conditions. In spite of a sufficiently large number of studies on justification of parameters of developing deep open pit levels, many questions still require additional research. This is primarily explained by the limited experience of operating articulated dump trucks in Russian deep open pit mines. In this context, the issue of justifying the optimal slope gradients for all-wheel drive models of motor vehicles remains relevant. The authors of the article have analyzed the existing normative documents and methods to determine the rate of longitudinal slopes. As the result of the study, the physical criterion of the least action is proposed as the optimization criterion for the slope gradients of the in-pit roads when operating all-wheel drive dump trucks.

Vegetation mantle change in the open pit mining area of Sin Quyen Copper Mine in Vietnam by satellite imagery data

The article presents the estimation results on the change in vegetation mantle in the region of Sin Quyen Mine (Bat Xat District, Lao Cai Province, Northern Vietnam) in the area of 19012 hectares. The normalized difference vegetation index (NDVI) and the vegetation mantle density change were calculated using satellite images Landsat 5 TM and Landsat 8 obtained between 1990 and 2020. In the period of copper mining for 30 years in the test area, the plant ecosystem has suffered the essential changes in the structure. From the remote sensing data and analytical results in 2020, the plant community is structured as follows. In the phase of high-rate mining (2000–2020), the sites with NDVI in the range of 0.4–0.6 prevailed (60.74%). The area of sites having NIDVI > 0.6 reduced by 3330 times—to 0.2%. The area of sites with NDVI in the range of 0.2–0.4 grew to 33.78%. The areas of sites with NDVI less the 0 and from 0 to 0.2 made 1.42 and 4.04%, respectively. Such structural changes are explained by drilling-and-blasting and by operation of drill rigs, shovels, dump trucks and dozers. The dusting objects are pit walls, working and nonworking sites, and overburden dumps. At the same time, an increasing trend is revealed in the areas of sites with low NDVI (by 1.5–6 times). The analytical estimation produced an inverse dependence of decrease in the area of sites with dense vegetation cover with increasing areas of mining and dumping. This dependence is explained by the progressive degradation of ecological situation in the region of open pit mining of the deposit composed of sulfide-bearing rocks. The studies were carried out in the framework of international cooperation in the sphere of wider application of remote sensing.

STAGGERED CREW PRODUCTION EVALUATION IN DEEP ORE ZONE UNDERGROUND MINING PT. FREEPORT INDONESIA

To increase production, the Deep Ore Zone (DOZ) mining department has a concept of implementing a staggered crew. A staggered crew is a crew formed specifically to support production activities. To assess the performance of the application of the staggered crew, an evaluation of the factors that influence production activities is carried out. Factors that are subject to evaluation are working time, number of operators, and production capability. The results of evaluating work time (optimum efficiency) for crew I, II, and III showed as follows 29%, 30%, and 28% respectively. Very low efficiency is due to time constraints in operation, which are affected by delay time, idle time, and maintenance time. Average productive work time (work) is 3.26 hours/day, delay time is 3.26 hours/day, idle time is 4.03 hours/day, and maintenance time is 0.53 hours/day. Idle time is the highest time of these four parameters. The results also showed that there were differences in the number of distribution operators, namely Crew I numbered 16 people, crew II numbered 12 people and Crew III numbered 15 people. But the number of operators on each crew is still sufficient to support production activities. The average production is 62.14 tons/hour and 4,784.78 tons/day. So with a production of 62.14 tons/hour and a working time of 11 hours/day, it takes a minimum of 8 dump truck operators to reach a value of 5,468.32 tons/day.

Truckers’ perceptions on truck regulations and policies in a developing country: A case study of Metro Manila, Philippines

Challenges in truck operation within metropolitan areas encourage the government to develop policies and strategies to address issues on truck traffic congestion and accidents. Given the need for making proactive policies, it is indispensable to understand truck drivers’ perceptions as a behavioral intervention measure. This paper examined the perception of truck drivers regarding issues on truck operation and policies, including their preferences on truck lane management and truck ban policies in Metro Manila, Philippines. The study surveyed 390 truckers in the North and South Harbor of Manila in July and August 2018. The survey results showed that most truck drivers have experienced difficulty with the existing truck ban and one truck lane policy in Metro Manila. Most truck drivers preferred two middle lanes for trucks, and truck ban time should be implemented during morning peak hours only. The willingness-to-pay attitude by truck drivers indicated a strong relationship with travel time-savings. Policy intervention should weigh up the perceptions of the stakeholders to provide a holistic approach and satisfactory truck management performance. This study would interest transport planners and policy developers as the findings can be applied to deal with truck operation issues.

Truck Dispatching Optimization Model and Algorithm Based on 0-1 Decision Variables

This study established a truck dispatching model adopting 0-1 decision variables to rationally allocate truck transportation in open-pit mines, maximize the total loading and unloading volume of trucks, and solve the problem of the inability of the truck dispatching model to guide production in open-pit mines because of nonspecific results. The model considers loading and unloading logical relationships, working time constraints, loading and unloading volume constraints, traffic flow constraints, and loading and unloading capacity constraints to maximize the total loading and unloading volume. The operation of trucks between loading and unloading sites is taken as the decision variable. The results show multiple transportation routings of all trucks between loading and unloading sites in working time. Double decision variables are used to solve the expression problem of constraints. The mathematical model is solved using Lingo. The proposed algorithm was then used to optimize the truck dispatching. The application result of the total loading and unloading volume was 10950.6 m3, and the total loading and unloading number was 384. The optimization result could guide production effectively.

Workforce Development Program untuk Pengembangan Masyarakat di Wilayah Operasi PT Chevron Pacific Indonesia

Workforce Development Program (WFD) is a community service program implemented by Politeknik Caltex Riau funded through a cost recovery mechanism by SKK Migas and PT. Chevron Pacific Indonesia (CPI). The background of this program relates to the unemployment rate condition in Riau Province (6.32%). This fact aggravated when Covid-19 hits the world and has an impact on laborers/workers lives, especially in Riau. There are workers who got termination as employment, some of them being laid off directly. WFD aims to provide additional skills and certificates for the workforce in Riau to have higher competitiveness index. The WFD program is implemented through the training and certification activities in the fields of Occupational Safety, Health and Safety Experts (AK3), Oil and Gas Occupational Safety, Health and Safety Operators, and Dump Truck Operators. The stages of the implementation program include socialization, recruitment, opening program, training, and certification (online, offline and blended training), and closing. There are 103 participants who pass as WFD 2021 beneficiaries. There are 101 participants who have passed the certification. The graduation achievement of the 2021 WFD Program is 98.06% (101/103). Based on the results of alumni tracing conducted 1 month after the training and certification phase, there were 25% of participants stated that the competencies they had when participating in WFD were able to increase their income.

ПОВЫШЕНИЕ ЭФФЕКТИВНОСТИ ЛЕСОВОЗНОГО АВТОПОЕЗДА ПУТЕМ ИСПОЛЬЗОВАНИЯ РЕКУПЕРАТИВНОГО ПНЕВМО-ГИДРАВЛИЧЕСКОГО СЦЕПНОГО УСТРОЙСТВА

The necessity of using timber trucks with trailers in order to increase the productivity of hauling timber has been substantiated. The advantages of using timber trucks with trailers over single timber trucks are described. The analysis of scientific works of foreign authors in the field of increasing the efficiency of timber trucks with trailers is carried out. An assessment was made of the operation of timber trucks with trailers in the existing conditions for the transportation of timber in the Russian Federation. The negative factors limiting the efficiency of timber-carrying road trains are revealed. The most significant factor, which can lead to dangerous consequences, is highlighted, which consists in the emergence of critically large forces in the coupling device of a timber road train during sudden braking. Changes in the braking forces of the bridges of a logging vehicle with a trailer during sharp braking, as well as three possible cases of interaction when braking a logging vehicle with a trailer, are considered. A promising design of a recuperative pneumohydraulic coupling device for a timber truck with a trailer has been proposed.