Mining Vehicle Research Articles

Integrated Positioning System of Unmanned Automatic Vehicle in Coal Mines

Automatic positioning technology of underground vehicles has become the key technology for the intelligent development of coal mines. To improve the comprehensive positioning accuracy of unmanned automatic vehicles in coal mines, an 18-D model of an odometer-aided inertial navigation system (INS) and a positioning model of an extended Kalman filter-based ultra-wideband (UWB) are established based on the vehicle kinematics equation. A tight integrated state estimation model is proposed to restrain the long-time drift of the INS and enhance the instability of the UWB system. A local positioning reference system based on an infrared motion capture system is established for the first time. Experimental tests show that the average positioning error of the proposed algorithm is 6.03 cm in the forward direction, and the root-mean-square error increased by 36.09% and 38.24% compared with those of the INS and UWB system, respectively. It is experimentally verified that the integrated positioning system achieves decimeter-level positioning accuracy in a coal mine roadway environment.

Concentrations and Size Distributions of Particle Lung-deposited Surface Area (LDSA) in an Underground Mine

ABSTRACT Ultrafine particles produced by diesel-powered vehicles in underground mines are largely unaccounted for in mass-based air quality metrics. The Lung Deposited Surface Area concentration (LDSA) is an alternative to describe the harmfulness of particles. We aim to study concentrations and size distributions of LDSA at various locations in an underground mine as well as to evaluate the applicability of sensor-type measurement of LDSA. This study was conducted in an underground mine in Kemi, Finland, in 2017. Our main instrument was an electrical low-pressure impactor (ELPI+) inside a mobile laboratory. Additionally, five diffusion-charging based sensors were tested. The environment was challenging for the sensors as the particle size distribution was often outside the optimum range (20–300 nm) and dust accumulated inside the instruments. Despite this, the correlations with the ELPI+ were decent (R2 from 0.53 to 0.59). With the ELPI+ we determined that the maintenance area had the lowest mean LDSA concentration (79 ± 38 µm2 cm–3) of the measured locations. At the other locations, concentrations ranged from 137 to 405 µm2 cm–3. The mode particle size for the LDSA distribution was around 100 nm at most locations, with the blasting site as a notable exception (mode size closer to 700 nm). Diffusion-charging based sensors—perhaps aided by optical sensors—are potential solutions for long-term monitoring of LDSA if dust accumulation is taken care of. Our research indicates worker exposure could be reduced with the implementation of a sensor network to show which locations need either protective gear or increased ventilation.

Probabilistic Membrane Computing‐Based SLAM for Patrol UAVs in Coal Mines

Patrol unmanned aerial vehicles (UAVs) in coal mines have high requirements for environmental perception. Because there are no GPS signals in a mine, it is necessary to use simultaneous localization and mapping (SLAM) to realize environmental perception for UAVs. Combined with complex coal mine environments, an integrated navigation algorithm for unmanned helicopter inertial measurement units (IMUs), light detection and ranging (LiDAR) systems, and depth cameras based on probabilistic membrane computing‐based SLAM (PMC‐SLAM) is proposed. First, based on an analysis of the working principle of each sensor, the mathematical models for the corresponding sensors are given. Second, an algorithm is designed for the membrane, and a probabilistic membrane system is constructed. The probabilistic SLAM map is constructed by sparse filtering. The experimental results show that PMC can further improve the accuracy of map construction. While adapting to the trend of intelligent precision mining in coal mines, this approach provides theoretical support and application practice for coal mine disaster prevention and control.

A study on localization system for mining vehicle

A study on localization system for mining vehicle

Structural configurations and dynamic performances of flexible riser with distributed buoyancy modules based on FEM simulations

Flexible risers are usually used as conveying systems to bring ocean resources from sea bed up to onshore. Under ocean environments, risers need to bear complex loads and it is crucial to comprehensively examine riser's configurations and to analyze structural dynamic performances under excitation of bottom vehicle motions, to guarantee structural safe operation and required service lives. In this study, considering a saddle-shaped riser, the influences of some important design parameters, including installation position of buoyancy modules, buoyancy ratio and motion of mining vehicle, on riser's configuration and response are carefully examined. Through our FEM simulations, the spatial distributions of structural tensions and curvatures along of riser length, under different configurations, are compared. Then, the impacts of mining vehicle motion on riser dynamic response are discussed, and structural tolerance performance is assessed. The results show that modules installation position and buoyancy ratio have significant impacts on riser configurations. And, an appropriate riser configuration is obtained through comprehensive analysis on the modules positions and buoyancy ratios. Under this proposed configuration, the structural tension and curvature could moderately change with buoyancy modules and bottom-end conditions, in other words, the proposed saddle-shaped riser has a good tolerance performance to various load excitations.

SWOT-assessment of recycling materials for cheap explosives used in the development of fields in the Russian Arctic zone

The recycling potential is being actualized due to the trends in the production and use of powder and liquid combustible materials from the waste of a mining enterprise in the production cycle of mining, enrichment and processing (polymer packaging and containers of explosives, large tires and rubber products during the operation of mining vehicles, coal powder and coke breeze during enrichment and coking of coal, waste oil products during the operation of vehicles and mechanization equipment). In the material under consideration, a SWOT analysis of the possibility of using the recycling technology of materials in the manufacture of the simplest explosives in the northern and arctic regions of Russia is carried out, including consideration of geological, natural, climatic, economic-geographical, environmental, technological and technical aspects. On the basis of the presented detailing of the indicators of the considered aspects of the SWOT analysis, their role is shown and the value is highlighted when using the technology of recycling materials for the simplest explosives in the development of medium and small deposits. The possibility of obtaining recycled material used for the manufacture of the simplest explosives at mining enterprises from alternative manufacturers is shown.

«Руский тип» подводных лодок: от «Дельфина» до «Барса»

The rise of submarine shipbuilding in Russia of 1900–1915 was influenced by the shortage of financial, technical and personnel resources. And yet the fleet received, along with American and German, boats of domestic design. Their design was concentrated in the hands of the outstanding theorist and engineer I.G. Bubnov, who announced the development of a special "Russian type" of a submarine that embodied the theoretical installations professed by him. The ships created according to Bubnov's designs are often regarded by fleet historians as unsurpassed in the world naval technology. Such a view contradicts the concrete data accumulated in historical research and needs critical consideration. For this purpose it is used classical methods of source studies and analysis of historiographical practice. The actual data indicate the harm brought to the fleet by the monopolization of scientific and technical activities. Submariners have developed a critical attitude towards the imposed type with its inherent number of persistent shortcomings. Bubnov refused to correct the shape of the hull which caused excessive water resistance. At the same time, in an effort to achieve the set speed of the boat, the designer envisaged in his projects such a powerful power plant that it exceeded the real capabilities of mechanical engineering and was also heavy and cumbersome. The boat commanders and engineers pointed out the need to reduce the submerging time of the boats, increase their survivability, add watertight bulkheads, abandon the low-impact mine vehicles of Dzhevetsky system, make the hull shape more streamlined, but the maritime administration preferred to save time and money and dismissed claims, sacrificing the comfort and safety of the crews. The experience of the First World War and familiarization with the most successful American and British designs nevertheless prompted I.G. Bubnov in 1915-1916. to revise the design principles concerning the shape of the hull, the internal structure of boats, the nature of engines, weapons, but the more advanced projects prepared by him could not be realized.

МОНИТОРИНГ ДИНАМИЧЕСКОГО СОСТОЯНИЯ АВТОНОМНЫХ ТЯЖЕЛЫХ ПЛАТФОРМ НА КАРЬЕРНЫХ МАРШРУТАХ ГОРНОРУДНЫХ ПРЕДПРИЯТИЙ

Purpose of work. The article presents the results of theoretical research and developments obtained at the Kuzbass state technical university on the implementation of current monitoring and bringing about signal processing procedures for the dynamic state of autonomous heavy platforms (AHP) on open pit mine routes. In order to obtain information about the generated current trajectories (CT) of unmanned mining dump trucks, in the software and hardware complexes of the computer-aided dispatching system (in the external control subsystem – ECSS and the autonomous control subsystem – ACSS) installed on-board of an AHP, one-dimensional (scalar) continuous signals (hereinafter converted into discrete digital ones) with a time-dependent instantaneous frequency, the so-called chirp signals, are put in accordance with the current trajectories of the AHP. Research methods. This approach makes it possible to continuously monitor and manage the dynamics of current ATP trajectories with a high degree of efficiency. Note that for the purpose of information-rich and semantically transparent representation of information about the current state of the AHP CT, the chirp signals of the CT are converted into multidimensional Cohen’s class time-frequency wavelet distributions. The Wigner-Ville distribution (hereinafter referred to as the Wigner distribution) is selected as a working tool for performing computational procedures in the hardware / software module. This distribution is based on the Gabor basis wavelet functions and the wavelet matching pursuit algorithm. The choice of Gabor wavelets as the main ones is explained by their sinusoidal-like shape, since they are sinusoidal signals modulated by the Gauss window. On the other hand, the analyzed 1D-signals indicating the current position of the AHP on the route are also sinusoidal-like. This makes it possible to approximate current signals with high accuracy based on their comparison with the wavelet functions selected from the redundant wavelet dictionary. This approximation is adaptive, since it is performed on separate local fragments of the signal analyzed depending on approximating wavelets. This is the essence of the wavelet matching pursuit algorithm. The resulting wavelet series is then transformed into the Wigner time-frequency distribution, which is used to form a corresponding CT. Research results. As an example, reconstructions of time-frequency distributions (TFD) are given, corresponding to the deviation of a certain CT to the left (the trajectory signal decreases exponentially) and to the right (the CT-signal increases) from the nominal axial trajectory (NAT). The calculated scalar signal and its TFD for the AHP CT deviating to the left from NAT are also presented. In addition, on the basis of theoretical explanations the calculated linear-increasing TFD is demonstrated, corresponding to the CT-deviation to the right from NAT, and the time invariant stationary TFD characterizing the movement of AHP along the NAT line. Сonclusion. Based on the results obtained, it is concluded that the most appropriate ways to monitor the current trajectories of AHP movement and procedures for processing the corresponding signals are the operations implemented in computer-aided subsystems of external and autonomous control and based on such concepts as the Cohen’s class wavelet distributions, Gabor redundant dictionary of wavelet functions, the wavelet matching pursuit algorithm, and the representation of technological chirp-signals, as well as frequency-stationary signals about the current AHP trajectories represented in the wavelet medium. In this connection, the authors concluded that the procedures realizing the current monitoring of AHP movement on open pit mine routes and implementing the process of analyzing a relevant dynamic change in current trajectories, described in the article and embedded in software and hardware autonomous and external control subsystems of "Smart opencast mine” are adequate for performing required functions. The introduction of the principles of computer-aided controlling the unmanned mining vehicles allows you to optimize labor costs for the operation of mining equipment, reduce the cost of current work, and attract highly qualified specialists for the development and operation of innovative transport equipment. The implementation of such prospects in mountainous regions (of a country) makes it possible to diversify the range of labor resources and, in general, contribute to the sustainable social and economic development of mountain territories.

Development of Targets for Heavy Duty Fuel Cell Vehicles with Application-Driven System Modelling

Hydrogen fuel cells are an attractive technology to power zero-emissions heavy-duty vehicles, including road vehicles, such as trucks and buses, as well as marine, rail, and mining applications. Hydrogen fuel cell powertrains can offer several advantages over incumbent technologies, such as diesel engines, including higher efficiency, reduced emissions, higher torque, and no noise pollution. Additionally, they offer fast fueling and adequate fuel storage for applications demanding longer range. In comparison to light duty fuel cell vehicles, which have begun early commercialization, fuel cell systems for heavy duty applications have important differences in their requirements and typical operation. Heavy duty fuel cell systems must offer high durability and efficiency to provide a competitive total cost of ownership considering capital costs, fuel costs, and lifetime. Furthermore, load-hauling applications, such as trucks, rail locomotives, and mining vehicles, must provide higher average and peak power while meeting heat rejection and onboard packaging constraints.Efforts to develop effective fuel cell materials, components, stacks, and systems for heavy duty applications must be guided by new targets and testing protocols. Fuel cell system modeling is essential to determine how application requirements translate to specific demands for the fuel cell system and components.The Department of Energy has set system-level targets for long-haul class 8 fuel cell trucks at 25,000 hour lifetime, 68% peak efficiency, and $80/kWnet fuel cell system cost by 2030 and ultimate targets of 30,000 hour lifetime, 72% peak efficiency, and $60/kWnet fuel cell system cost.[1] This presentation will discuss the system-level targets as well as the development of new targets and testing protocols for heavy duty fuel cell components and materials. This includes specific performance tests for different operational requirements, accelerated stress tests, and targets combining durability, performance, efficiency, and cost. We will also discuss differing needs between heavy duty applications, each of which presents unique requirements for fuel cell systems. It is desirable to address these unique requirements with standardized, cross-platform fuel cell stacks and components to enable high volume, low cost manufacturing, which requires the development of suitable cross-platform targets. [1] U.S. Department of Energy. “Hydrogen Class 8 Long Haul Truck Targets”. DOE Hydrogen and Fuel Cell Technologies Program Record. December 12, 2019: https://www.hydrogen.energy.gov/pdfs/19006_hydrogen_class8_long_haul_truck_targets.pdf

The Passive Fire Protection of Mining Vehicles in Underground Hard Rock Mines

Vehicle fires in underground mines pose a certain risk for which measures to prevent or mitigate the fires are highly important. This paper presents a study on passive fire protection measures to counter this risk, where data from full-scale fire experiments, cone calorimeter tests and statistical studies were applied. It addressed an overall question: what passive fire protection measures could be implemented with respect to the design of mining vehicles? Relying entirely on one type of passive measure may only be adequate for a specific stage of a fire and additional measures may be warranted for the other stages. Threshold distances for fuel components were calculated, and it was found that the combination of hydraulic hoses and electrical cables resulted in larger threshold distances, contributed to by the higher flame heights of the hydraulic hoses and the lower critical heat flux of the non-fire-resistant electrical cables. A pool fire along the underside of the vehicle will pose a certain risk, and passive fire protection measures should be focused at ignition prevention, making high demands on the insulation/shielding along the underside. Tyre fires could be prevented by steering the flow of flames and fire gases away from the tyres. An increased knowledge of such possible passive fire protection measures would improve the fire safety in underground mines.

Postural balance effects from exposure to multi-axial whole-body vibration in mining vehicle operation

Twenty participants (18 males and 2 females) completed postural stability assessments before and after 4-h exposure to whole body vibration (WBV) in four experimental conditions: (a) vertical-dominant WBV with vertical passive air suspension, (b) multi-axial WBV with vertical passive air suspension, (c) multi-axial WBV with multi-axial active suspension, and (d) no WBV condition. Center of pressure (COP)-based postural sway measures significantly increased following multi-axial WBV exposure. Increase in COP velocity and displacement following multi-axial WBV was significantly higher than the increase in all the other exposure conditions. However, no significant differences between the WBV conditions were observed in functional limits of stability and anticipatory postural adjustments. While our results show standing balance to be impaired following the multi-axial WBV exposure of off-road mining vehicles, dynamic stability across a broader range of conditions needs to be understood to causally link postural stability decrements to increased fall-risks associated with off-road vehicle operators.

Thermal Runaway Pressures of Iron Phosphate Lithium-Ion Cells as a Function of Free Space Within Sealed Enclosures

Mining vehicle manufacturers are developing lithium-ion (Li-ion) battery electric vehicles as an alternative to diesel-powered vehicles. In gassy underground mines, explosion-proof (XP) enclosures are commonly used to enclose electrical ignition sources to prevent propagation of an internal methane (CH4) air explosion to a surrounding explosive atmosphere. Li-ion batteries can create pressurized explosions within sealed enclosures due to thermal runaway (TR). Researchers at the National Institute for Occupational Safety and Health (NIOSH) measured TR pressures of lithium iron phosphate (LFP) cells as a function of free space within sealed enclosures and observed an inverse power relationship. A well-confined cell produced 294 bar (4260 psia) of pressure during a TR, far exceeding minimum pressure containment specifications for conventional XP enclosures. Results indicate that adding enough free space surrounding LFP cells can reduce TR pressures to levels below that expected for CH4-air ignitions. Measured TR temperatures were below the minimum autoignition temperature of CH4-air.

A new dynamic model and trajectory tracking control strategy for deep ocean mining vehicle

Mobility and controllability of a deep ocean mining vehicle directly determine its operational efficiency and safety. In this study, the spatial hydrodynamic distributions acting on a mining vehicle under different motion states were ascertained through the computational fluid dynamics (CFD) numerical simulations. Then, a new multi-body dynamic (MBD) model of the vehicle integrated with its hydrodynamic effects and vehicle-sediment mechanics interaction was established. An underwater test of a tracked prototype vehicle in a large-scale laboratory water tank was performed and validated the feasibility and accuracy of the new MBD model. Furthermore, a controller based on a fuzzy self-adaptive PID method for the predetermined trajectory tracking of the mining vehicle was designed and modelled. Finally, the real-time information exchange and collaborative simulation between the developed MBD model and the controller were realized and proved that the proposed motion controller had a satisfactory performance in the trajectory tracking control for deep ocean mining vehicles.

Velocity-Free Localization of Autonomous Driverless Vehicles in Underground Intelligent Mines

The rapid progress of science and technology has created favorable conditions for the development of autonomous driverless vehicles. However, the complex conditions in the cities greatly limit the application and promotion of autonomous driving technology. To solve the problem, the underground mine is recommended to apply as a pilot for the promotion of autonomous driverless vehicles. The autonomous vehicles are all connected to the internet to form a vehicle-to-vehicle (V2V) system. Because of the multi-levels and multi-stopes in underground mines, the key point is to obtain the precise locations of the vehicles in real-time. Therefore, the microseismic monitoring, image recognition technology, artificial intelligence training, and smart sensors are comprehensively utilized, based on the internet of things and cloud computing, to locate the autonomous driverless vehicles. Virtual sources localization and pencil lead break tests are conducted to simulate and eliminate the effectiveness and accuracy of the velocity-free localization method. Virtual sources localization demonstrate that the velocity-free localization method is accurate and reliable. Results of pencil lead break tests show that the average locating errors of X coordinates, Y coordinates, and absolute distance are 0.4318 cm, 0.1136 cm, and 0.5188 cm, respectively. The application and promotion of the autonomous driverless vehicles in underground mines can not only solve the problems of deep mining and reduce the frequent disasters caused by the harsh conditions but also can protect the life and property of the workers, as well as provide technical support for the safe and efficient recycling of deep resources.

Underwater Localization System Combining iUSBL with Dynamic SBL in ¡VAMOS! Trials.

Emerging opportunities in the exploration of inland water bodies, such as underwater mining of flooded open pit mines, require accurate real-time positioning of multiple underwater assets. In the mining operation scenarios, operational requirements deny the application of standard acoustic positioning techniques, posing additional challenges to the localization problem. This paper presents a novel underwater localization solution, implemented for the ¡VAMOS! project, based on the combination of raw measurements from a short baseline (SBL) array and an inverted ultrashort baseline (iUSBL). An extended Kalman filter (EKF), fusing IMU raw measurements, pressure observations, SBL ranges, and USBL directional angles, estimates the localization of an underwater mining vehicle in 6DOF. Sensor bias and the speed of sound in the water are estimated indirectly by the filter. Moreover, in order to discard acoustic outliers, due to multipath reflections in such a confined and cluttered space, a data association layer and a dynamic SBL master selection heuristic were implemented. To demonstrate the advantage of this new technique, results obtained in the field, during the ¡VAMOS! underwater mining field trials, are presented and discussed.

What localizes beneath: A metric multisensor localization and mapping system for autonomous underground mining vehicles

AbstractRobustly and accurately localizing vehicles in underground mines is particularly challenging due to the unavailability of GPS, variable and often poor lighting conditions, visual aliasing in long tunnels, and airborne dust and water. In this paper, we present a novel, infrastructure‐less, multisensor localization method for robust autonomous operation within underground mines. The proposed method integrates with existing mine site commissioning and operation procedures and includes both an offline map‐building process and an online localization algorithm. The approach combines the strengths of visual‐based place recognition, LIDAR‐based localization, and odometry in a particle filter fusion process. We provide an extensive experimental validation using new large data sets acquired in two operational Australian underground hard‐rock mines (including a 600m‐deep multilevel mine with approximately 33 km of mapping data and 7 km of vehicle localization) by actual mining vehicles during production operations. We demonstrate a significant increase in localization accuracy over prior state‐of‐the‐art SLAM research systems and real‐time operation, with processing times in the order of 10 Hz. We present results showing a mean error of 0.68 m from the Queensland Mine data set and 1.32 m from the New South Wales Mine data set and at least 86% reduction in error compared with prior state of the art. We also analyze the impact of the particle filter parameters with respect to localization accuracy. Together this study represents a new approach to positioning systems for currently deployed autonomous vehicles within underground mine environments.

Calibration Optimization Methodology for Lithium-Ion Battery Pack Model for Electric Vehicles in Mining Applications

Large-scale introduction of electric vehicles (EVs) to the market sets outstanding requirements for battery performance to extend vehicle driving range, prolong battery service life, and reduce battery costs. There is a growing need to accurately and robustly model the performance of both individual cells and their aggregated behavior when integrated into battery packs. This paper presents a novel methodology for Lithium-ion (Li-ion) battery pack simulations under actual operating conditions of an electric mining vehicle. The validated electrochemical-thermal models of Li-ion battery cells are scaled up into battery modules to emulate cell-to-cell variations within the battery pack while considering the random variability of battery cells, as well as electrical topology and thermal management of the pack. The performance of the battery pack model is evaluated using transient experimental data for the pack operating conditions within the mining environment. The simulation results show that the relative root mean square error for the voltage prediction is 0.7–1.7% and for the battery pack temperature 2–12%. The proposed methodology is general and it can be applied to other battery chemistries and electric vehicle types to perform multi-objective optimization to predict the performance of large battery packs.

Analysis of the Current Challenges for Deep Underground Mines: Labour Productivity Improvement

With much of the ore deposits close to the surface already discovered and mined, the mines are becoming deeper, and this brings multiple challenges. One of the challenges is the longer haul distance from active mining areas to the mine surface, hence longer transportation time of material and operators. Longer transportation time of operators may lead to the reduction of the labour productivity. Labour productivity in today’s mines is a key importance, and is currently dependent on together with other factors that operators should be at the vehicles or working area on time. There has been some development in mine automation, but the vast majority of underground mine operations are still in need of operators. Several methods are available and can be used to transport operators to the underground working areas. These methods include mine vehicles, mine taxis, mine buses, monorail, and shaft system. As mine depth increases, the method with higher labour productivity will be of much useful in operator’s transportation. The aim of this study is to investigate personal transportation methods for deeper underground operations by comparing labour productivity when using mine vehicle, mine taxi, mine buses, and monorail system. The results show that mine vehicle has higher labour productivity of up to 76% of available time, while mine buses have low labour productivity. It has been reveal that for shallow depth mines, a good option to improve labour productivity is to have few operators transported per cycle, while for deep mines, a transport system that is faster, accommodate few operators per cycle, less possibility to meet traffic will be the better option for labour productivity improvement.

Substantiation of parameters of metal structure elements of mining transport machines

The relevance of the work is due to the need to reduce the metal consumption of mining vehicles while maintaining the strength characteristics of their metal structures. An effective tool for finding the best option for combining the design parameters is optimization theory from the point of view of obtaining the design with the required properties. The implementation of the principles and approaches of this theory in relation to the metal structures of mining transport vehicles allows achieving a combination of their geometric characteristics, which makes it possible to obtain the smallest mass and dimensions. Purpose of the work: development of the principle of obtaining mathematical dependencies, allowing to determine the most suitable shape and size of the cross section for the elements that make up the metal structures of mining vehicles, taking into account the direction of the loads perceived by each element. Research methodology. An optimization approach is used, including the definition of the design parameters, the formulation of the objective function and the restrictions imposed on the design parameters. Results and their application. The factors affecting the value of the optimal parameters in the elements of the metal structures of mining vehicles are established. The optimal parameters of the cross section are substantiated for various combinations of the perceived load direction and the priority requirements for metal construction. The obtained recommendations can be applied in the design of frames with a minimum weight or dimensions. Conclusions. The recommendations presented allow us to reasonably choose the best cross-sectional shape of the metal elements of mining transport vehicles, depending on the direction of the current loads. The requirements for metal construction, such as minimum metal consumption and (or) surface area, are taken into account. For rods working in tension or compression, the most rational is the square shape of the cross section. For bending elements, a rectangular section with a height/width ratio of two is best suited. These conclusions are drawn from considerations of the least metal consumption and the smallest surface area of the metal structure. Taking the proposed recommendations into account when designing the metal structures of mining transportation machines will allow us to obtain the lowest values of metal consumption, and, consequently, the cost of the machine with the required technical characteristics.

A comparative study of transmissibility factors of traditional and pneumatic dumper seats using one-third octave band analysis

Severity of exposure to whole-body vibration of vehicle drivers depends on multiple factors including type of vehicle suspension or quality of seats. The study presents analysis of seat vibrations of two different types of dumpers in opencast mines. Since health guidance provided in ISO 2631-1997 are only indicative, seat effective amplitude transmissibility factors along with one-third octave-band analysis of vibration signals have been considered as more effective information for control measures. Vibration characteristics of conventional seats ( n = 3) with rigid frame and those with pneumatic suspensions ( n = 3) have been compared during their use in mines. A(8) values ranged from 0.66 to 1.41 m/s2. All the six operators had shown moderate to higher health risk but this may vary since both intensity and durations of exposure frequently change during the operators’ employment. Vibration signals from a mono-axial accelerometer (z′) placed on the cabin floor was captured in addition to three channel vibration data (x, y and z) of a seat pad accelerometer placed on the vehicle seat. Transmissibility analysis of vibration signals from cabin floor to seat surface showed that the three pneumatic seats resonated in the range of 1.6–2.5 Hz in the z axis. There was significant attenuation of vibration energy ranging from 37% to 63% at 4 Hz which is important in the context of spinal injuries. The seat effective amplitude transmissibility values (%) in the resonating frequencies ranged from 119% to 173%. Interestingly, the conventional seats resonated at 4–5 Hz and the corresponding seat effective amplitude transmissibility (%) values were varying from 128% to 163%. This resonance at 4 Hz is in sharp contrast with the behaviour of pneumatic seats. It is recommended that vibration transmissibility should be considered as a major design parameter for mining vehicle seats.