Trackless Vehicle Research Articles

Development of Synchronous Transportation Model for Trackless Vehicle Dispatching During the Construction of Long‐Distance Single‐Headed Shield Tunnel

With the increasing demands for long‐distance single‐headed tunnels, trackless vehicles have been widely accepted for transporting construction materials from storage yard to working face. During the trackless transportation of construction materials, the synchronization of material supply and shield tunneling is critical to ensure tunneling efficiency. However, there is still a lack of a reliable synchronous transportation model for trackless vehicle dispatching. In the present study, the material transportation processes and vehicle transportation parameters have been investigated based on the Sutong GIL Yangtze River Crossing Cable Tunnel. The synchronous transportation model has been established to improve transportation efficiency during the construction stage. An optimized scheme of vehicle schedule has been proposed to minimize trackless vehicle and retention time. Comparative analysis has been carried out to evaluate the trackless vehicle and retention time between the optimized scheme and the original scheme. The results indicate that the number of dual‐headed trucks required for material transportation decreases from nine to six, and the maximum retention time decreases from 166 to 35 min. Compared with the original scheme, the optimized scheme is available for reducing the number of trackless vehicles and improving the efficiency of material transportation. The present study contributes to optimizing material transport scheduling and synchronizing material supply with tunnel excavation in long‐distance single‐headed shield tunnels.

Operational tests of a small-sized farm multi-purpose vehicle

The paper deals with the issue of expanding the scope of application of small-sized farm multi-purpose vehicles in the production process. The authors focus on the risks associated with the use of this type of machines. The authors prove that application of small-sized farm multi- purpose vehicles is feasible in agricultural production. To increase the interest of agricultural producers in small-sized farm vehicles it is necessary to develop a system of reliable assessment and verification of their actual consumer properties. For this purpose, the authors have studied the existing normative and technical documentation related to the functioning of this type of machines, varieties of small-sized vehicles and electrically driven trackless vehicles. Based on the available documents, they arranged a list of necessary tests to fully evaluate the main consumer properties. The test set consisted of nine procedures, including both static and dynamic tests. The paper provides data on the developed and manufactured experimental sample of electric cargo tricycle used on farms. The tricycle served as an example for the cycle of tests carried out according to the developed list. The paper summarizes the results obtained. Particular attention is paid to longitudinal and lateral sliding and tipping stability tests, center of mass position and traction tests, as well as dynamic tests to determine speed and braking performance, the mileage on a single battery charge, and vibration loading when operating under various road and climatic conditions.

Optimization of Truck–Loader Matching Based on a Simulation Method for Underground Mines

The choice of transportation system has an important impact on the production efficiency and economic behavior of underground mines. Trackless vehicle transportation has gradually become the main method in underground mines because mining companies have realized that mining efficiency can be improved using advanced vehicle mechanization and automation in the mining process. The extracted ore is loaded onto trucks by loaders in situ, then the trucks drive to ore passes for unloading Trucks load and unload ore in a cyclical manner between stopes and ore passes. Numerous trucks drive in tunnels simultaneously to achieve production targets, and there are interactions and influences among trucks, such as blocking and queuing, due to limited underground space. To address this issue, a transportation route model was built, and the ore transportation process was divided into three parts, including ore loading, truck transportation, and ore unloading. The simulation method was applied to optimize the number of loaders and trucks under the constraints of stope production capacity, transportation route and capacity, and vehicle capacity, to achieve the optimal vehicle utilization rate and transportation capability. The Monte Carlo simulation method was utilized to take the uncertainties of the transportation parameters into account to improve the robustness of the simulation results. The model was verified using the case study of an underground gold mine located in Shandong Province, China, with the objective of accomplishing optimal truck–loader matching considering various stopes in a mining area.

Design and Optimization on the Degree of Hybridization of Underground Hybrid Electric Trackless Rubber-Tyred Vehicle

The explosion-proof diesel engine trackless rubber-tyred vehicle (TRTV) has the disadvantages of high fuel consumption and serious exhaust emissions, while the problems of insufficient power and short endurance limit the development of the explosion-proof battery trackless rubber-tyred vehicle. Hybrid technology can effectively reduce fuel consumption and emissions on the basis of ensuring sufficient power. Exploring the application of hybrid electric trackless rubber-tyred vehicle (HETRTV) has practical significance for coal mine auxiliary transportation. The degree of hybridization (DOH) will directly affect the performance and cost of TRTV, which needs to be focused in the development process. The effects of DOH on dynamic performance, fuel economy, emission performance, and cost were studied based on a simulation by ADVISOR, and the results were verified and analyzed by experiment. Compared with the flameproof diesel engine trackless vehicles, HETRTV with the optimal DOH exhausts has far less gas emissions. The engine fuel consumption and the equivalent fuel consumption of the vehicle are reduced by 33.9% and 12.5%, respectively. The results showed that in spite of a small increase in cost, the HETRTV with the optimal DOH can not only meet the driving requirements of underground working conditions but also greatly improve fuel economy and emission performance.

Comparative studies on the maneuverability of track trains for transportation of containers

To increase the cross-country ability of ground trackless vehicles for off-road container transportation by land, it is advisable to use track trains. When moving track trains, it is necessary to ensure high profile cross-country ability when overcoming obstacles in the vertical and horizontal planes. The property of maneuverability determines the ability of track trains to maintain mobility when maneuvering in the plan and depends on the adopted design and layout solutions and static agility. The article examines the maneuverability of track trains for two variants of design and layout solutions: a track single-articulated semi-trailer train and a double-articulated track train. The movement of each of the track trains is compared according to the criterion of energy efficiency, taking into account two methods of turning: kinematic and power turning methods.
 A variant of the design and layout of a track train was determined. It has better static agility and a smaller overall turning radius.
 To assess energy efficiency, the method of simulation mathematical modeling is used, taking into account the peculiarities of the interaction of the driving machine with the support base. The article provides a description of the regulators that are used in the mathematical model and provide the turn of caterpillar trains with a minimum radius. To compare the energy efficiency of performing maneuvers, several design schemes are considered: with one active link or with two active links.
 A turning method was determined. It is advisable to use it to ensure high turnability of track trains. The effect of the length of the bearing surfaces of caterpillars active links on energy efficiency is determined as well. In addition, the results of a comparison of track trains according to the criterion of energy efficiency are given.

ПОВЫШЕНИЕ УСТОЙЧИВОСТИ ДВИЖЕНИЯ ПРИЦЕПНЫХ АВТОТРАНСПОРТНЫХ СРЕДСТВ

Today, automobile and tractor trains with trailers are quite popular vehicles used for transporting agricultural goods in the agro-industrial complex of the Russian Federation. Road trains and trac-tors with trailers are characterized by lower performance indicators (maneuverability, stability of movement) than single vehicles. Accordingly, special requirements for safety and trouble-free op-eration are imposed on motor-tractor trains. The author of the article proposes a technical solution that provides longitudinal stability of the movement of multi-link trackless vehicles, and has, in comparison with known analogues, simplicity of design and increased efficiency in the operating conditions of multi-link tractor trains. Analytical studies have been carried out, which made it possible to justify the rational kinematic and geometric parameters of the proposed technical solu-tion. The strength parameters of the damping device installed at the coupling point of tractors and trailers, and ensuring the operational reliability of trailed dump vehicles, are determined. The re-sults of the conducted research are recommended to both domestic and foreign research institutes, design and production structures of the automotive industry for further study and refinement of the proposed device with a view to its possible introduction into practice.

Ensuring the safety of operation of the truck with the semi-trailer

This article raises an important issue of road train stability under various operating conditions, it also discusses one of the elements of active safety in the operation of road trains consisting of a truck tractor and a semi-trailer, namely the ordering of the mutual position of the parts of the train. A brief overview of the principle of operation of various schemes designed to prevent the folding of a tractor with a semi-trailer, as well as structural and functional capabilities, some disadvantages and advantages is given. The new and one of the latest implementation systems for blocking the folding of a trackless vehicle consisting of a semi-trailer is presented. The blocking mechanism for folding a train includes a closed kinematic chain using flexible coupling, as well as a controlled closed hydraulic system. There are certain promising possibilities of this proposed technical solution in terms of increasing active safety in the operation of the trailer and organizing the provision of controllability of the saddle tractor relative to the semi-trailer interconnected with the steering and steering wheels, with the position of the brake pedal sensor road trains, with driver’s actions, weather conditions and traffic situations.

Acceleration Analysis of Tubular Constrained Damping Engine Mount

Trackless vehicles have been widely used for the underground mining in many coal-rich countries. However, their vibration is violent and this vibration could affect the driver's health and reduce the working efficiency. Therefore, how to solve this question about the vibration and shock has become an urgent and important thing. In this paper, a type of tubular constrained damping engine mount is designed and first used in the underground trackless vehicles. This tubular damping structure is made of three layers, the external and internal layer are made of steel and the middle layer of natural rubber is sandwiched between them. To know about the vibration-reducing performance of the new designed mounts, the real vehicle test was performed under two working conditions. The results show that the two rear mounts could obtain good vibration isolation effect, whereas the performance are sometimes poor in a certain direction for the two front mounts because of the vibration energy coupling in different directions. Further research is to optimize the parameters of the tubular constrained damping engine mount to make the vibration energies from different directions decoupled.

A Novel Relative Navigation Control Strategy Based on Relation Space Method for Autonomous Underground Articulated Vehicles

This paper proposes a novel relative navigation control strategy based on the relation space method (RSM) for articulated underground trackless vehicles. In the RSM, a self-organizing, competitive neural network is used to identify the space around the vehicle, and the spatial geometric relationships of the identified space are used to determine the vehicle’s optimal driving direction. For driving control, the trajectories of the articulated vehicles are analyzed, and data-based steering and speed control modules are developed to reduce modeling complexity. Simulation shows that the proposed RSM can choose the correct directions for articulated vehicles in different tunnels. The effectiveness and feasibility of the resulting novel relative navigation control strategy are validated through experiments.