Search

In the paper is presented Neuro-Fuzzy System as a decision-making support in the selection of construction machines (the example of selecting a loader is provided). Construction characteristics of a loader make the basis for selection, but also other elements of importance. The data for Neuro-Fuzzy System modeling are prepared using the Multi-Criteria Decision Making (MCDM) methods: Logarithm Methodology of Additive Weights (LMAW), VIKOR, TOPSIS, MOORA and SAW. The paper also presents the method of aggregation of weights of rules premises (AWRP), which defines the key rules of Neuro-Fuzzy System. Finally, the training of the model is tested. The data for the selection of input variables and for model training are obtained by engaging experts.

The aim of this work is to design a variable universe fuzzy control of a wheel loader semi-active cab suspension with damping multimode switching shock absorber. Considering the cost and reliability, a new type of shock absorber, whose adjustable damping characteristics are achieved by just changing the on–off statuses of two solenoid valves, is applied to the wheel loader cab suspension. The vibration model of the wheel loader, which considers the vibration characteristics of the working device, the four-wheel correlated random road excitation, and the engine vibration excitation simultaneously, is established first. Based on the working principle of the target shock absorber, the damping multi-state switching model is also established to reflect the relationship between the damping coefficients and the on–off statuses of two solenoid valves. Then, a variable universe fuzzy damping control strategy, which can determine the optimal switching sequences of the damping modes according to the cab suspension performance indexes, is designed. Finally, simulation analyses were conducted to verify the effectiveness of the proposed control approach of the wheel loader semi-active cab suspension with multimode switching shock absorber.

This paper evaluates the effectiveness of similitude theory in predicting the draft of a rubber tire loader’s bucket during initial penetration. The work uses 1:16 and 1:8 scale models of an 18-t capacity load haul dump, scaled with the Buckingham Pi Theorem, to evaluate the prediction of draft and penetration under different operating and different dynamic conditions. The authors hypothesize that the observed relationships between draft and longitudinal penetration and the operating and dynamic conditions will hold true for an upscaled model. Similarly, the authors hypothesized that the results of experiments conducted with the smaller scaled model should predict the draft on an upscaled model. The results show that the relationships between draft and longitudinal penetration and operating and dynamic parameters are similar for both scaled models. Similarly, the draft on the upscaled model, predicted by using the experimental results of the small model, is similar to the measured draft on the upscaled model. The mean difference between the two is 1.71 N with 95% confidence interval of [-3.51, 6.93], which is very good given the average draft is approximately 330 N. Thus, the work indicates that both hypotheses are true for draft. However, the work shows that scaling muck pile particle sizes using the Buckingham Pi Theorem is not adequate to ensure good predictions of penetration. This work provides insights that will help design engineers to acquire useful data on scaled models and use it for various analyses on heavy machinery.

According to the typical working conditions of a loader and considering the complexity of the working conditions, the hydrodynamic transmission powertrain system was modeled in this study. Because the hydrodynamic torque converter is a flexible fluid transmission component in the transmission system, this study proposes and establishes equivalent variable damping and equivalent variable stiffness models of the hydrodynamic torque converter. Based on this, a torsional vibration simulation model of the loader with variable damping and stiffness is proposed, and the frequencies and amplitudes of the torsional resonance modes of the transmission system varying with engine speed and hydrodynamic torque converter speed ratio are obtained. It is determined that the variable stiffness of the hydrodynamic torque converter has little effect on the natural frequency of the vehicle, and taking variable damping and stiffness as input, the natural frequency and resonance points of the transmission system can be calculated more accurately. The simulation modeling and calculation approach are experimentally verified, and the simulation results are valid and closer to the real resonance.

The hydraulic hybrid powertrain has great potential for reducing fuel consumption and emission of off-road vehicles. The energy management strategy is the key to hybrid powertrain and currently there are many well-developed strategies. Of which the Pontryagin’s minimum principle is of research interest since it is a global optimization method while less computational burden than dynamic programming. However, it requires full cycle information to calculate co-state value in the principle, making it not implementable. Therefore in this study an implementable Pontryagin’s minimum principle is proposed for a series hybrid wheel loader, where the optimal co-state value in the principle is trained through repetitive wheel loader duty cycle. The Pontryagin’s minimum principle formulations of hybrid wheel loader are developed. The online co-state training algorithm is presented. A dynamic simulation model of hybrid wheel loader is developed. The fuel consumption of hybrid wheel loader with proposed strategy is compared with dynamic programming strategy and rule-based strategy in wheel loader long and short loading cycles. Results show the fuel consumption with proposed strategy is close to dynamic programming result and is lower than rule-based strategy. Finally, the influence of pressure level of hybrid powertrain on vehicle fuel consumption is studied.

The open pit mining load and haul system has been a mainstay of the mining industry for many years. While machines have increased in size and scale and automation has become an important development, there have been few innovations to the actual load and haul process itself in recent times. This research highlights some of the potential productivity and safety benefits that the incorporation of a surge loader may bring to the load and haul system through an analysis of the system, discussion of component characteristics, and mine planning aspects. The incorporation of the surge loader into open pit loading and haulage operations also enables improved safety. This is a result of a reduction in shovel–truck interactions and the reduced likelihood of truck overfilling and uneven loading. This paper details the number of mine worker deaths that a surge loader may have prevented within the Peruvian and Chilean mining industries.

The task of the conducted research is to determine the dependence of the productivity of the cutter-loader on the parameters of the engagement of the teeth of the wheel-rack mover of chainless haulage systems. To solve this problem, the dependence of the influence of the parameters of the toothed gearing of the wheel-rack mover of the chainless haulage system on the performance of the cutter-loader is found using the mathematical apparatus. The equation of the balance of the power of the cutter-loader is made, taking into account the mechanical energy input for the destruction of the formation, loading the destroyed mineral mass onto the face conveyor (relevant for cutter-loaders for excavating thin flat-lying seams) and moving the cutter-loader. The theoretical performance of the cutter-loader depends on the redistribution of the mechanical energy of the drive electric motor, aimed at the destruction of the mineral and the translational movement of the cutter-loader. The correlation of the productivity of the cutter-loader with the parameters of the engagement of the teeth of the wheel-rack mover of chainless haulage system systems is revealed. The obtained dependences of the performance of the cutter-loader allow assessing the degree of influence of the parameters of the toothed gearing of the mover of the chainless haulage system on the performance of the cutter-loader. The possibility of increasing the minute productivity of the cutter-loader by up to 20% when using a wheel-rack mover of a chainless haulage system with an optimal tooth profile is established.

Coal is still a part of energy generation worldwide and has a significant role in the sustainable development of countries. The amount of shallow coal deposits is getting scarce, making efficient underground mining operations crucial for both local and global economies. In underground mining operations, longwall mining is a commonly utilized method to extract deep coal deposits. One of the leading engineering goals in longwall mining is increasing the efficiency of the system by investigating the effects of operational factors on equipment. This paper investigates the shearer performance for a longwall top coal caving operation by discrete event simulation that includes modeling the double-drum shearer, belt conveyors, stage loader, and armored face conveyors (AFC) to evaluate system performance by considering the amount of daily coal production of the shearer. As a result, the most influential factor on mine production is determined and a data-based framework is developed. This study suggests a framework for data collection, data analysis, and the interpretation of the operational data to evaluate the primary production unit’s performance. The models developed for the face coal extraction operations in a longwall top coal caving (LTCC) mine have a bi-directional cutting system and can be implemented in other operations readily.

One of the most important influencing factors on the economy of mines with surface and underground exploitation is the correct choice of haulage technology of ore and waste.The paper analyzes the haulage of ore and waste in the Lead and Zinc Mine “Sase” Srebrenica and determines the optimal haulage length on the four excavation blocks for the application of the new haulage system by using the mine trucks from the aspect of set criteria, increasing capacity and reducing haulage costs through the techno – economic analysis and optimization.The optimal haulage length is determined through the calculations of the loader capacity and the possible choice of the truckdepending on the stated criteria.

The article presents studies into aerodynamic processes in very long longwall panels. The computations in ANSYS using the finite volume method show that air drag in longwalls varies versus position of the longwall mining system in the panel. Enhancement of ventilation efficiency in longwalls requires reduction in air drag. The longwall air drag is governed by the air drags of the powered roof support and cutter-loader. The latter have very large dimensions which are technologically unchangeable. For this reason, it is necessary to ensure forced air flow to by-pass the cutter-loader in the longwall panel. The estimate of advantages of the proposed method for the air drag reduction in very long longwall panels is presented. The method consists in increasing air flow rate in the longwall with the help of an axial jet fan mounted on the cutter-loader.

The increase in oil prices, consumables and tools is necessitate the re–equipment of mining enterprises in Ukraine. The share of automobile transport reaches 35–50 % in the dimension blocks production costs. The purpose of the work is to determine transportation costs (TC) of 1 m3 of blocks depending on the volume and transportation distance within the quarry; improving the transportation plan by solving transportation problems of linear programming. Fuel consumption and dimension block TC for three models of front–end loaders (FEL) were newly calculated on the basis of a comprehensive study. A comparison of the economic feasibility of FEL and dump truck (DT) use in certain mining conditions have been made. The rationalization plan (RP) of dimension blocks transportation within the quarry was newly proposed. The research was performed at the dimension gabbro quarry, blocks transportation in which is performed using FEL CAT 988F (1) and DT KrAZ–256B. FELs CAT 988H (2) and CAT 986H (3) were adopted for comparison. The average annual fuel consumption is determined: among the FELs considered in the research, the (3) consumes the least, and the (1) currently used at the enterprise consumes 22.7 % and 9.7 % more fuel compared to the (3) and the (2), respectively, in similar conditions. Trade blocks transportation using FEL is economically more expedient in comparison with the DT at transportation distance up to 300–400 m. It is determined that the trade blocks TC using the (2) and the (3) is 5.3 % and 12.6 % lower, respectively, compared to the (1). This paper also considers the transportation problem for FELs, in which blocks from several banks must be distributed between several storage areas, provided to minimize TC. According to the proposed RP of transportation, the savings will be up to 13 % compared to the initial conditions, which in monetary terms is 41538–48639 UAH/year depending on the FEL model. The replacement of the (1) for the (3) will reduce block TC by 12.6 % (47000 UAH/year) in the current conditions. The TC using the (3) will be 285303.5 UAH according to the proposed RP, which is 23.7 % (88476 UAH/year) less than the (1) application before the rationalization. Keywords: dimension stone; front–end loader; commercial blocks transportation costs; transportation problem; cargo traffic rationalization; fuel consumption; haul road gradient.

The fuel consumption, productivity and operability are three important performance criteria for construction machinery. Better fuel economy sometimes means reduced productivity while higher productivity requires more powerful powertrain and thus consumes more fuel. It is challenging to compromise these performances in a single machine. However for working sites with multiple machines running together, it is possible to balance fleet fuel consumption and productivity with proper site operation strategy. In this study a site operation strategy for wheel loader/truck loading and transportation cycle is developed. A comprehensive criterion balancing the trade-off between fleet fuel consumption and fleet productivity – the fleet operating cost, is proposed. The strategy takes both fleet configuration parameter (number of wheel loaders and trucks) and operating parameter (wheel loader cycle time) into considerations. The fleet fuel consumption is calculated based on vehicle powertrain models instead of empirical estimation. The fleet fuel consumption, productivity and fleet operating cost with different numbers of wheel loader/truck and wheel loader cycle times are obtained. The optimal number of wheel loader/truck and wheel loader cycle time to achieve minimum fleet operating cost are identified.

One of the most significant goals of earthmoving equipment is to maximize productivity during loading cycles. A real-time knowledge of the forces exchanged between the machine implement and the surrounding, that is, while digging, can be used in different ways to increase productivity. It can be used to determine the amount of material moved by the machine; or to find the optimal bucket trajectory; moreover, as input to traction control systems. This article presents an online force estimation algorithm able to predict vertical and horizontal forces exchanged between the front-loader and the surrounding environment, as well as the reaction forces through the implement itself. Taking the case of a 14-ton wheel loader as reference, this article illustrates the development of a simulation model for the analysis of the machine digging system, along with the instrumentation and testing of the proposed estimation algorithm. The model is divided into two sections describing, respectively, system kinematic and system dynamics. The kinematic model of the front-loader is compared against measurements, and results show an average error lower than 1%. The dynamic model predicts both hydraulic and dynamic features of the machine implement, achieving an accuracy on the payload mass within 2%–3%, even during dynamic conditions. The estimated pushing force reflects the expected behavior when tested for various pushing efforts and in different ground conditions. Eventually, the algorithm was tested on a complete loading cycle and the results show good consistency considering the measured front-loader trajectory and vehicle speed. The proposed model overcomes some drawbacks of the currently used technologies. For example, it allows for an online estimation of the bucket forces for any position of the implement. Although the results discussed in this article pertain to a specific reference machine, the proposed method can be extended to most wheel loaders equipped with standard digging equipment.

A multi-bale handling unit offers an advantage for the efficient hauling of round bales. Two empty racks on trailers are left at a satellite storage location for loading while a truck tractor delivers two loaded racks to the biorefinery, thus uncoupling the loading and hauling operations and increasing the efficiency of both. The projected 10 min trailer exchange time equals the projected 10 min unload time at the biorefinery achieved by lifting off the two full racks and replacing them with two empties, a technology adapted from the container shipping industry. A concept is presented for a bale loader that latches onto the rack/trailer and loads bales into the bottom tier chambers. This machine will load 10 bales into the rack on the front trailer by attaching on to the front of the trailer and 10 bales into the rear trailer by attaching onto the rear. A telehandler removes bales from single-layer storage and places them in the bale loader to load the bottom tier compartments. The top tier compartments are loaded directly from the top. Expectations are that an experienced operator can average 9 loads in a 10 h workday, and load-out cost is estimated as 3.61 USD/Mg, assuming the average achieved load-out productivity over annual operation is 60% of optimum productivity (24 Mg/h) equal to 14.4 Mg/h. Cost increases to 4.81 USD/Mg when the productivity factor drops to 45%, and cost is 3.09 USD/Mg for a factor of 70%. Published version

The E. coli γ clamp loader is a pentameric complex of δ, δ′ and three γ subunits that opens and loads β-clamp proteins onto DNA in an ATP-dependent process essential for efficient DNA replication. ATP binding to the γ subunits promotes conformational changes that enable the clamp loader to bind and open the ring-shaped β-clamp homodimer. Here we report the nearly complete backbone and side-chain (1)H, (13)C and (15)N NMR resonance assignments of the 242-residue truncated γ subunit of the clamp loader complex, which includes the N-terminal mini (domain I) and lid (domain II) domains. This construct represents the nucleotide binding module in the clamp loader complex and provides a model system for studies of conformational rearrangements of the clamp loader induced by nucleotide binding.

The purpose of the paper is the risk assessment of the health and safety at work while working with hydraulic loader crane. After assessing the risk, appropriate preventive measures for healthy and safe work were prescribed, together with a brief health and safety manual. The expert finding of the hydraulic loader crane was processed according to the model of already finished expert findings, according to the Regulation of examination and testing of work equipment and investigation of work environment conditions („Official gazette of RS“, no. 94/2006, 108/2006 – corr., 114/2014 and 102/2015).

On the basis of machines with an articulated frame it is possible to create a complex of machines for road construction, repair and maintenance. Therefore, a number of comprehensive studies are needed to increase their reliability and durability. This is especially true of the main joints of the articulated joint and the hydraulic steering, which ensure the rotation of the frame parts around the vertical hinge. The research was performed in two stages. At the first stage the mathematical model of dynamic interaction of the working equipment of the car with the developed environment was created and investigated. In the second stage, a machine experiment was performed to determine the loads on the bearing system. The mathematical model is based on the physical model of the loader, which consists of three elements: two hinged parts of the frame, one installed energy module, the other ‒ the technological module and the connecting and control module. The Lagrange equation of the second kind served as a basis for modeling the dynamics of the equivalent calculated dynamic model. The solution of the complex system of differential equations allowed to obtain all the required values, which have a significant impact on the formation of the load of the coupling-control device. According to the results of mathematical modeling, the ranking of factors that affect the load of the hydraulic drive of the coupling and control device. The machine experiment allowed to determine the load on the load-bearing system and to study the effect of the impact loads from the working equipment on the hinged connection of the frame parts. As the analysis of the mathematical model showed, the place of application of force to the bucket, the angle of assembly of the frame parts and the initial speed of the loader have a significant effect on the load of the hydraulic drive. The load of the hydraulic cylinders is determined by the place of application of force to the bucket. The change in the circular torque of the coupling and control module, taking into account the characteristics of the material being developed and the stiffness of the tires, must be taken into account when calculating the frame of the articulated machine and the hydraulic drive.

HighlightsPhysical models of module builder and module loader were developed to enhance biomass testing with reduced mass and volume of biomass.Models used dimensional analysis, Pi Terms, and engineering factors and emphasis on reduced module upsetting and disturbance.Some engineering terms such as tamping face pressure and velocity, and particle size were not scaled to reduce biological-material distortions.Switchgrass bulk density at 8% wet basis for prototype and model were 115 and 80 kg m-3, respectively.Abstract. The objective was to design and implement separate models of a first-generation cotton module builder and a module loader that facilitated tamping quasi-confined biomass and the minimal disturbances of modules during emptying from the builder and during loader operations including unloading. The 122-cm long model, compared to 978-cm long prototype, reduced the mass of module contents required for testing from 6188 to 44 kg, or by a factor of 141:1. The tamping process was emphasized with constant tamper pressure of 76.6 kPa applied to module contents for prototype and model. Consistent properties such as SG characteristic length were also held constant among module sizes to reduce the complications of introducing un-anticipated biological-material distortions. Similarities in design aspects beyond dimensional analysis were emphasized to reduce inadvertent module upset and disturbance. Hydraulics ensured uniform tamping and lifting. An efficient module box for the model resembled the prototype-scale commercial unit with z-shaped ribs and upward-tapered module sides. Seed cotton [8% moisture wet basis (w.b.)] bulk densities for prototype and model were 166 and 107 kg m-3, respectively. Bulk densities for switchgrass (8% w.b.) prototype and model were 115 and 81 kg m-3, respectively. Reduced bulk density of models was attributed to essentially no external confinement stresses being applied to modules at rest resulting in only self-imposed confinement stresses due to module content over-burden. However, unconfined modules may have a role in handling biomass for reduced distances. Also related to minimizing module upsetting, module loading emphasized the counter-motions of advancing the loader versus the conveyor motion in the opposite direction, all driven with an electric motor. Module stability during loading was attributed to a self-imposed normal stress of module weight acting downward onto a horizontal plane of the module. The fixed loading angle of 15° and material bulk properties were held constant between prototype and model. Dependent variable for the module loader was normal stress for module stability. Normal stresses resulting from seed cotton at 8% moisture content (wet basis) were 4.754 and 0.637 kPa, respectively. Normal stresses for chopped SG at 8% moisture content (wet basis) were 3.302 and 0.484 kPa, respectively. Biomass modules would not be as stable as cotton modules based on normal stress, and due to lack of intermeshing cotton fibers. Results of loading and unloading a dozen SG model modules resulted in one module failure due to upset, and that was attributed to a 2-layer fill versus 3-layer fill for that one module. Keywords

This article presents a deep reinforcement learning-based controller for an unmanned ground vehicle with a custom-built scooping mechanism. The robot’s aim is to autonomously perform earth scooping cycles with three degrees of freedom: lift, tilt and the robot’s velocity. While the majority of previous studies on automated scooping processes are based on data recorded by expert operators, we present a method to autonomously control a wheel loader to perform the scooping cycle using deep reinforcement learning methods without any user-provided demonstrations. The controller’s learning approach is based on the actor-critic, Deep Deterministic Policy Gradient algorithm which we use to map online sensor data as input to continuously update the actuator commands. The training of the scooping policy network is done solely in a simplified simulation environment using a virtual physics engine, which converges to an average of a 65% fill factor from the full bucket capacity and a $5\left [{ sec }\right]$ average cycle time. We illustrate the performance of the trained policy in simulations and in real-world experiments with 3 different inclination angles of the earth. An additional scooping experiment compared the performance of our controller to remote manual human control. Overall, the deep reinforcement learning-based controller exhibited good performance in terms of both achieved visually bucket fill with varying scooped earth weights of $4.1-7.2[kg]$ , and a $5.1-7.1[sec]$ cycle time. The experimental results confirm the ability of our planner to fill bucket as required, indicating that our controller can be used for excavation purposes.

The article provides a methodology for determining the theoretical study of the movement of potato tubers and impurities in a lifting centrifugal-separating bar elevator in potato harvesters. Most of the separating working bodies, which separate the components according to other characteristics, cannot work satisfactorily if there is a large amount of fine soil in the separated mass. Based on the results of the research carried out by us on the experimental installation, the layout of the pressure-pressure cylinder in the potato harvester was determined. This device separates the soil by centrifugal forces, and the lifting of the tubers produces a difference from known machines, without buckets or blades. A drum with a belt conveyor is located concentrically to the belt of the centrifugal elevator.

The results of the use of loaders in the manufacture of various products using dry mixes are analyzed.

After analyzing the technology of natural stone mining in Russia in comparison with European countries, we conclude that one of the ways to increase the efficiency of the mining transport equipment system in natural stone quarries is to use wheel loaders more widely. Wheel loaders are characterized by high maneuverability, productivity, and are able to combine excavation, transportation, shipping, as well as perform auxiliary work. At the same time, the loader is very effective for providing access to any section of the quarry after stripping loose overburden and waste that impede movement. To increase the profitability and economic efficiency of natural stone quarrying, it is advisable to use a wheel loader as the main handling, transport and auxiliary equipment. The main reason why wheel loaders equipped with attachments are not widely used in the development of natural stone deposits in Russia is their high cost, which significantly increases capital and operating costs since the main manufacturers of wheel loaders equipped with quick-mounted attachments are such brands as Comatsu, Caterpillar, Volvo, Hyundai, etc. For these purposes, the mounted auxiliary equipment for the CHETRA PK 120 wheel loader of domestic production was designed. The strength of the coupler metalworks and and its hydraulic exponents are calculated. During the design, hydraulic equipment was selected to control and regulate attachments. In case of using the proposed system, the investment costs will decrease, and the proposed organizational and technical measures will increase the efficiency of mining companies due to reduced operating costs.

PurposeThere have been numerous efforts to tackle the problem of accumulated construction and demolition wastes worldwide. In this regard, this study develops a model for identifying the optimum fleet required for waste transportation. The proposed model is validated through a case study from the construction sector in New Cairo, Egypt.Design/methodology/approachVarious fleet combinations are assessed against the time, cost, energy and emissions generated from waste transportation. Genetic algorithm optimization is performed to select the near-optimum solutions. Complex proportional assessment and operational competitiveness rating analysis decision-making techniques are applied to rank Pareto frontier solutions. These rankings are aggregated using an ensemble approach based on the half-quadratic theory. Finally, a sensitivity analysis is implemented to determine the most sensitive attribute.FindingsThe results reveal that the optimum fleet required for construction and demolition wastes (CDW) transportation consists of one wheel loader of bucket capacity 2.5 cubic meters and nine trucks of capacity 22 cubic meters. Furthermore, consensus index and trust level of 0.999 are obtained for the final ranking. This indicates that there is a high level of agreement between the rankings. Moreover, the most sensitive criterion (i.e. energy) is identified using a sensitivity analysis.Originality/valueThis study proposes an efficient and effective construction and demolition waste transportation strategy that will lead to economic gains and protect the environment. It aims to select the optimum fleet required for waste transportation based on economic, social and environmental aspects. The usefulness of this study is establishing a consensual decision through the aggregation of conflicting decision makers' preferences in waste transportation and management.

The performance of a wheel loader (WL) can be improved with the application of a power reflux hydraulic transmission system (PRHTS) with a capacity adjustment device (CA-device). However, due to CA-device’s unique working principle, the traditional shifting strategy is not suitable for CA-device. Apply traditional shifting strategy to CA-device will result in frequent or incorrect shifting. In order to solve this problem, this paper proposes applying the working condition identification to the CA-device shifting strategy. Combining the working principle of PRHTS with CA-device and the analysis of WL V-condition, the requirement for the working condition identification algorithm of the CA-device shifting strategy is obtained, and a working condition identification algorithm for WL V-condition is designed. Simulation results show that applying the working condition identification algorithm to the CA-device shifting strategy can avoid frequent shifts and incorrect shifts. A hardware-in-the-loop platform is built to verify the real-time performance of the shifting strategy. Results show that the proposed shifting strategy exhibits a satisfactory level of real-time performance.

Background: In recent years, the incidence of prostate cancer (PCa) is increasing. Advanced PCa has a poor prognosis and high cost, which seriously affects the quality of life of patients. Therefore, how to improve the diagnosis rate and prognosis of early PCa is the focus of clinical research. This paper aims to investigate the value of P504s, 34βE12, Ki-67 and prostate-specific antigen (PSA) in the diagnosis and prognosis of PCa. Objective: To investigate the expression of P504s, 34βE12, Ki67 and PSA in prostate tissues and their clinical significance. Methods: Twenty four cases in the study group were selected from PCa confirmed by pathology in the urology department of Chengde Affiliated Hospital from October 2018 to August 2020, and 33 cases of Benign Prostate Hyperplasia (BPH) confirmed by pathology in the same period were selected as the control group. The expression of P504s, 34βE12 and Ki-67 in prostate tissues were determined by immunohistochemistry. Results: The positive expression rates of P504s, 34βE12 and TPSA or F/TPSA in PCa patients were 95.8%, 12.5%and 87.5%, respectively. The positive rates in BPH patients were 9.1%, 93.9% and 27.3%, The difference between the two groups was statistically significant (p

A wheel loader is representative construction machinery that is designed to load material in off-road applications. The vehicle moves back and forth in the loading process, showing great hydraulic hybridization potential. The research target in this study is a compact wheel loader. By adding hydraulic energy storage device – hydraulic accumulator, it is turned into a series hydraulic hybrid. In this paper the system modeling and controllers design of series hydraulic hybrid wheel loader were illustrated. A tunable energy management strategy has been proposed and studied. By changing the hybrid weight factor in the strategy, the powertrain hybridization degree was adjusted without any additional hardware. This study shows that higher use of the hydraulic accumulator power indicates a higher degree of hydraulic hybridization. Results show that the series hydraulic hybrid wheel loader has a fuel saving of 18.9% compared to a hydrostatic wheel loader in the short loading cycle. Studies had also been conducted to show the trade-off between the fuel consumption and the vehicle performance with different hybridization degrees.

Decoupling the end-effector motion from that of the mobile base of mobile manipulators traversing uneven terrains is important. This is especially so in mining, where material spillage from excavators and front-end loaders reduces productivity and slows down operations because of increased clean-up and maintenance times. Thus, this article proposes a strategy that relies on $\mathcal {H}_\infty$ feedback control combined with feedforward action to improve the rejection of terrain disturbances that affect the orientation of the end-effector. The dynamic model of the mobile manipulator considers a floating base with nonpermanent contacts at each wheel, hydraulic actuators with nonlinear dynamics and a nonrigid arm. The arm flexibility is modeled as a passive spring-damper joint to account for inherent cantilever effects of real excavators and loaders. The analysis considers three different $\mathcal {H}_\infty$ controller structures (single-input single-output (SISO) with feedforward, single-input multiple-output without feedforward, and multiple-input multiple-output without feedforward) to determine the benefits or disadvantages of employing the pitch rate of the mobile base as a feedforward control action or as an input handled by the $\mathcal {H}_\infty$ controller and using only the end-effector actuator or also the other actuated joints of the arm. The root-mean-square error (RMSE) was reduced between 73.8%–86.0% when driving an industrial semiautonomous skid-steer loader over a ramp using the SISO $\mathcal {H}_\infty$ controller with feedforward action. The tilt angle error was kept on average less than $0.9\pm 0.1^\circ$ . The same controller yields a reduction of the RMSE between 23.5%–38.4% and a tilt angle error smaller than $3.39\pm 0.07^\circ$ on average when traversing over a bump. Hence, the strategy proposed to reject ground disturbances should contribute to reducing material spillage of existing autonomous machines that navigate with little operator intervention along mining galleries, but that cannot avoid disturbing material lying on the ground or the characteristic unevenness of mining terrains.

In order to control the impact behavior of the microprobe test process in microelectronics final test, based on the rapid response and intelligent controllability of magnetorheological (MR) fluid, a novel micro-MR flexible loader was designed to be loaded into the microprobe test system. The results show that the new system can effectively achieve smooth loading, and over-loading could be avoided by adjusting the control current of the loader during large loading displacements. Under different parameters such as loading current, loading speed, and loading displacement, a series of test experiments were carried out and the loaded mechanical response of the probe was collected. Based on statistical analysis on a large amount of experimental data, the law of stable pressure and multiparameter is obtained. Finally, by fitting the data, multiparameter numerical models are obtained. It will provide a numerical basis for the application of the new flexible loading system.

This paper presents a semi-active type magnetorheological (MR) fluid-based mount for effective vibration control of a wheel loader cabin. Traditional passive (viscous) mounts are inadequate at providing a large damping force and low elastic modulus over a wide frequency range; hence, the ride comfort of the driver and work efficiency per day are limited. In the present study, to overcome this limitation, MR mounts were designed considering principal geometry and dimensions of existing viscous mounts and installed to a vehicle cabin for vibration control. After investigating the field-dependent dynamic stiffness of the manufactured MR mounts, a field test on road traveling was conducted. In the field test, vibrations from the vertical and horizontal directions are evaluated with respect to the vehicle speed. In addition, vibration control performances between conventional viscous mount and the proposed MR mounts were compared showing superior performances of the reduced acceleration transmissibility and amplitude with on-off controlled MR mounts.

Diesel particulate matter (DPM) is carcinogenic to humans. Underground miners have a high risk of over-exposure to high concentrations of DPM. To control DPM effectively, it is essential to understand the DPM dispersion characteristics. In this study, the DPM distributions of three key and representative mining activities, shotcreting, charging and loading activity, in an underground development face were studied. A computational model for the mining activities was developed using 3D imagery, onsite data and OpenFOAM. Tracer gas experiments were first conducted in the underground mine for the validation of CFD simulation. The simulations were carried out at a steady-state using the standard k-e turbulence model, and the transport and dispersion of DPM were modelled using a segregated species transport model. DPM distribution characteristics for each mining activity were analysed, and the regions with high concentration (>0.1 mg/m3) were identified, and the reasons for the high concentrations were also discussed. At last, the efficiency of the current auxiliary ventilation system on DPM dilution was evaluated based on the simulation results. The results show that a broader region with high DPM concentration was identified in the downstream of the loader during the loading activity, and this issue could be solved by simply increasing the ventilation rate. The findings in this paper could be used for optimizing the auxiliary ventilation design for future mining activities in this development face.

This work evaluated the effect of bucket orientation and operating parameters on resistive forces and penetration for rubber tire loaders. The work used a 1:16 scale LHD model to test a rubber tire loader (RTL) bucket operating at different levels of tractive effort, speed, digging height, and rake angles in a full factorial design experiment. The work repeated the test on two different muck piles with different particle sizes and used generalized regression modeling to test the association of rake angle, tractive effort, speed, and digging height on penetration and resistive forces for RTL buckets. The results show that speed and tractive effort are more important in explaining RTL penetration and resistive forces than height above the floor and rake angle. Speed, tractive effort, and height above the floor are positively correlated to bucket penetration, whereas the rake angle is negatively correlated to penetration. Similarly, speed, tractive effort, rake angle, and height above the floor are all positively correlated to resistive forces incurred during initial penetration. The observation that the combined effect of speed and tractive effort is negatively correlated to penetration and resistive forces is a novel contribution that enhances our understanding of RTL loading. The results also show that the effect of speed, tractive effort, and height above the floor all change with changes in particle sizes. This work adds to the literature on the effect of rake angle, height above the floor, tractive effort, and speed on penetration and resistive forces for rubber tire loaders.

Recent studies have demonstrated that the power-cycling hydrodynamic mechanical (PCHM) transmission has excellent performance in improving power performance and fuel economy of a wheel loader. However, these results have been obtained by assuming that its speed ratio can always change continuously. Hence, this study first investigated the speed ratio of the transmission how to change when shifting from one gear to another. It was found that the concept of the PCHM transmission suggested in the literature is ineffective, even for a configuration with two gears in the gearbox. Then, the configuration of the PCHM transmission was developed as a different one to increase the torque multiplication capacity and efficiency of the transmission. A design method for this transmission is proposed to quantify its performances. The design method is based on a multi-objective optimization problem which is comprised of two objectives, seven design variables and eleven constraints. The relationships between average efficiency of the transmission and maximum tractive force of the vehicle and the seven transmission parameters are qualitatively examined. Results show that the performance of the transmission depends mainly on the number of transmission gears instead of on three parameters of the torque converter. The average efficiency is not sensitive to the maximum tractive force on a globally optimal Pareto front. The PCHM transmission with the new configuration can enable the average efficiency and the maximum tractive force to increase by 2.1 % and by 6.6 %, compared to that of the traditional hydrodynamic mechanical transmission, respectively.

Articulated wheeled loader vehicles have frequent rollover accidents as they operate in the complex outdoor environments. This article proposes an active anti-rollover control method based on a set of single-frame control moment gyro stabilizer installed on the rear body of the vehicle. The rollover dynamic model is first established for articulated wheeled loader vehicle with gyro stabilizer. The proposed control strategy is then applied in simulation to verify the rollover control effect on the vehicle under steady-state circumferential conditions. Finally, a home-built articulated wheel loader vehicle with gyro stabilizer is used to further verify the proposed control strategy. The results show that the vehicle can quickly return to the stable driving state and effectively avoid the vehicle rollover when a suitable anti-roll control moment can be provided by the gyro stabilizer. As a result, the articulated wheeled loader vehicle is able to operate safely in a complex outdoor environment.

The article presents a method for solving the problem, eliminating the oscillations of the load on the knuckle join suspension the simultaneous movement of two elements of the boom system, namely, lifting the jib and movement the telescopic section. The essence of the method is based on the optimization of the regime of simultaneous movement of two elements of the boom system of the loader crane during horizontal movement of the load during the start-up period. As an optimization criterion, a complex integral criterion was selected, which is a relative root-mean-square value of forces and powers in hydraulic drive cylinders. The developed criterion displays the undesirable properties of the boom system elements and drives mechanism, therefore, its values are minimized. Since the optimization criterion is an integral functional, variational calculus method are used to optimize it. The solution of the variational optimization problem is presented in the form of many parametric functions that satisfy the boundary conditions of motion and minimize the complex dimensionless criterion. For this purpose, the particle swarm optimization method (ME-PSO) was used. This made it possible to obtain the dependences of the optimal, energy and forces characteristics of the boom system and the drive mechanisms of the crane. The mode of movement of the boom system elements obtained as a result of optimization improved the forces and energy characteristics of the loader crane, which made it possible to increase its reliability and productivity.

In 2012, the International Agency for Research on Cancer (IARC) classified diesel particulate matter (DPM) as a carcinogen to human. With the increased usage of diesel equipment in underground mines, miners have a high risk of over-exposure to DPM, which has drawn many concerns from the public. This study used computational fluid dynamics (CFD) to analyse the DPM dispersion and concentration distribution characteristics in an underground development face based on an onsite experiment. The DPM emitted from a moving loader under a forcing auxiliary ventilation system was simulated. The motion of the load-haul-dump (LHD) in the tunnel was represented by a dynamic mesh method. The species transport approach was applied to study the DPM behaviours. High DPM concentration zones were then identified based on the simulation results. The results could provide guidelines for work practices and be helpful to an optimum auxiliary ventilation design to reduce underground miner exposure.

Vibration machines make up a large class of construction and road construction equipment. The improvement of vibration machines is carried out in the direction of improving the vibration device as the main working body of the machine. For a long time, vibrators with circular vibrations are used as vibration devices, the effectiveness of which is not always sufficient when performing special work on immersing piles into and removing them from the soil. The priority area of development and creation of vibration devices for technological processes in the coming years is mechanisms with asymmetric oscillations. Vibration devices with asymmetric oscillations can significantly increase the efficiency of using vibration machines due to the fact that the driving force aimed at performing useful work exceeds the magnitude of the driving force directed at idling several times. However, at present there is no method for determining and calculating the parameters of vibration devices with asymmetric oscillations instead of circular vibrators. The purpose of the article is to consider a method for designing vibrational devices with asymmetric oscillations, based on the method of expanding a given function of changing the value of the total driving force into a Fourier series, the terms of which are the values of the driving forces generated by each stage of a multi-stage vibration mechanism. The study is based on classical analytical and numerical methods. The results obtained allows to use the methodology for evaluating the design method of a vibration device with asymmetric vibrations at the design stage and to evaluate the effectiveness of the designed vibration device.

One of the key issues in automatic shift control of V-type cyclical loaders is determining how to find the best gear for the current conditions according to a certain mapping relation, but this complex and nonlinear mapping is difficult to express by a mathematical relation. However, to solve such nonlinear problems, a radial basis function (RBF) neural network is the best choice. In this paper, a certain type of wheel loader is taken as the research object, and an RBF neural network algorithm based on an improved genetic algorithm (GA) optimization is proposed. The global search ability of the GA is improved by adaptively adjusting the crossover probability and mutation probability. The RBF neural network expansion coefficient is optimized by an improved GA. Using industrial IOT technology, an optimized RBF neural network based on Map-Reduce on a cloud computing cluster is designed. The diesel engine computer and transmission computer on the loader are integrated to achieve dual-processor distributed parallel data processing and calculation. Then the loader automatic variable speed control algorithm model of improved GA optimized RBF neural network based on IOT cloud computing is established. The network model is trained and simulated using real vehicle automatic shift test data. The simulation results show that the improved GA-RBF neural network algorithm can achieve a correct recognition rate of 97.92%. The error matrix norm reaches the minimum value when the algorithm is iterated to the 17th generation. The improved algorithm has the advantages of a high gear recognition rate, fast convergence speed and strong real-time shift performance and is an effective new shift control method. The test results show that the shift boost time is less than 0.15 s and has a certain gradient. Compared with the manual shift process performed in the past, some improvements are achieved in the optimal shift time, shift response speed and shift quality. Compared with the traditional single computer based on serial training RBF neural network learning algorithm, whether it is Great progress has been made in convergence speed, training time, recognition rate, and data processing capabilities. Through the simulation and test, the validity of the intelligent shift control method of the improved GA optimized RBF neural network based on IOT cloud computing is verified. It has better engineering application value.

In this paper, the wheel loader with electrohydraulic proportional control technology is used as the carrier. For the first time, the dual-angle sensor is used for intelligent operation, which allows the wheel loader working device to be precisely controlled. First, the theoretical analysis of the electrohydraulic proportional control technology on the wheel loader studied in this paper is carried out. Next, according to the feedback of the boom and bucket angle sensor signals, the electrohydraulic proportional control technology is used to initially realize the boom memory and bucket automatic levelling function of the wheel loader working device. Finally, the data acquisition equipment is connected to provide experimental verification, although the test results did not achieve precise control of the working device. After analysis, the detected problems were solved by constructing a neural network algorithm model, which successfully realizes the intelligent and precise operation of the wheel loader, reducing unnecessary energy loss.

The working device of wheel loader undergoes complicated load cycles in operation with changing attitude all the time. However, it is difficult to duplicate the exact load history in lab. The common practice is to apply a fixed load attitude and equivalent load, to the working device to assess its fatigue life. In this paper, a modeling technique to calculate equivalent attitude and equivalent load is proposed. In the process of equivalent model establishing, the damages at critical points are considered. The finite element method is used to obtain the strain time history to compare with tested data.

Currently, for the needs of agriculture, more than 30 different pressure trucks have been developed.In addition to the generality of the technological process, there is a common structural design of front-end loader machines - their main components are identical: the support frame - for connecting the loader to the tractor, a lifting frame or a lifting boom, lifting hydraulic cylinders, a working body.The technological process is performed by a front-end loader of pressure action in the following modes: deepening mode, crane and transport modes.It is well known that only on the basis of the theory of oscillations can practically completely clarify such practically important problems as balancing machines, torsional vibrations of shafts and gears, precession of rotating shafts, oscillations of mechanisms under the action of moving loads. Only with the help of this theory can the most successful designs be established, pushing the operating conditions of the machines as far as possible from the conditions of the occurrence of large fluctuations.The issue of the dynamics of heavy machines is currently becoming of paramount importance due to the fact that in agricultural production there are natural tendencies to increase the productivity of working machines as a result of increased loads and an increase in their pace of work.The nature of dynamic loads in the actuators of working machines largely depends on the adopted technological scheme, on the nature of the operations that must be reproduced during operation, and finally, on the type of actuator and its drive.The technological process of operation of front-end loaders of pressure action is carried out by them according to one scheme: the translational movement of the unit to capture material, is loaded and loaded into transport containers, the load is lifted along a vertical circular path.The obtained dependences of the load bearing structures of the loader and tractor on their design parameters can be used by design organizations when designing new front-end loaders and other implements, they are front-hung on wheel tractors.

This study applies image recognition technology to the shovel loading operation of a wheel loader for the first time. In the proposed method, the wheel loader can automatically select the corresponding engine power curve according to different identifiable materials, thus achieving intelligent energy saving. This study first analyzed the working resistance of the wheel loader, and the analysis results provided theoretical support to the energy-saving operation of the wheel loader. The shovel loading test was carried out for different materials. The test results validated the feasibility of intelligent energy-saving operation of the wheel loader based on identifiable materials. A neural network algorithm based on material identification model was then built and verified, whose material identification rate was 92 %. The model was used as the carrier, and the wheel loader-operating characteristics were considered in view of the existing engine energy-saving mode. Finally, the boom cylinder pressure and bucket angle were used as feedback to future discussion about the intelligent energy-saving operation of the wheel loader. The basic conditions for subsequent designs of wheel loaders are provided.