Hydraulic Excavator Research Articles

Many-objective Optimization Design for TriRocker Working Mechanism of Face-shovel Hydraulic Excavator

Many-objective Optimization Design for TriRocker Working Mechanism of Face-shovel Hydraulic Excavator

Lifetime Reliability of Hydraulic Excavators’ Actuator

Lifetime Reliability of Hydraulic Excavators’ Actuator

ОБОСНОВАНИЕ ПАРАМЕТРОВ ЭКСКАВАТОРНО-АВТОМОБИЛЬНЫХ КОМПЛЕКСОВ НА УГОЛЬНЫХ РАЗРЕЗАХ С УЧЕТОМ ФАКТОРА НАДЕЖНОСТИ

The article presents the factors affecting the performance of excavators and dump trucks. The main dependences of the technical readiness coefficient of hydraulic excavators (Hitachi, Volvo, Komatsu PC, Liebherr) with a bucket capacity of 1...3.5 m3, in combination with articulated dump trucks Volvo, Bell, BelAZ (with a load capacity of 10-20 tons), quarry dump trucks BelAZ, Terex, Caterpillar, Komatsu (40.100 tons) are given. To increase the efficiency of the process of transporting rock mass at coal mines, the regularities of changes in the performance of quarry dump trucks have been studied. The obtained research results allow us to make a forecast assessment of the annual operational productivity of mining and transport equipment when planning the work of coal mining enterprises in the short term.

Synthesis of basic geometry parameters of excavator working equipment

Problem. Single-bucket excavators have become one of the most popular machines today, which are widely used to perform a variety of construction works. The working area or service area is one of the main characteristics of the work equipment of the manipulation type. It must meet certain requirements, which are: the largest digging depth, unloading height and digging radius at the level of the parking lot. To ensure the parameters of the given working area, it is necessary to correctly select the basic geometry of the working equipment: the length of the boom and the handle, the turning radius of the bucket edge. Goal. The purpose of the work is to automate the synthesis of basic geometry parameters of the hydraulic excavators, according to the specified parameters of the service area (working area). Methodology. A system of non-linear equations establishing a relationship between the geometric parameters of the working equipment and the parameters of the working area was obtained. Results. The software for the OS Windows was developed. The program outputs not only numerical results. To visualize them, contours of the resulting working area are built. Originality. The relationship between the geometric parameters of the working equipment and the parameters of the working area has been established. A mathematical model and software for automating the synthesis of geometric parameters of working equipment have been developed. Practical value. The developed software can be applied not only at the design stages of new types of excavator working equipment, but also in the process of preparing the machine for specific types of work. The proposed approach can also be extended to the synthesis of parameters of the lever mechanisms of other construction machines, in particular, the working equipment of loaders, looseners, etc.

TECHNOLOGICAL EFFICIENCY BY CHANGING THE CRANE EQUIPMENT

The paperwork includes some considerations regarding the way of establishing the constructive and functional main parameters needed to adapt a crane equipment on a tire excavator. Using a crane equipment on tire excavator is an advantage both for the economy of a service rendering company and for meeting many requirements from various customers. The work equipment on multipurpose excavator is obtained by replacing the work equipment on dragline or grab crane by single hook. Adapting the crane equipment, in case the excavator is provided with dragline equipment, is only the suitable choice of single hook. Specific for such equipment are load lifting – lowering, boom slewing together with excavator platform, boom inclining and travelling function of base machine which, according to load, amplifies the equipment working area. By adapting a crane equipment to tire excavator, a new equipment is got, which, in my opinion, can be part of tire cranes family. Changing the work equipment – hydraulic excavator bucket with crane equipment – shows some advantages like: high maneuverability and mobility, access in narrow spaces, occasional use of crane equipment, equipment cost price is much lower than for a tire crane, only specialized for loads lifting, slewing and travelling.

Application of High Precision Mining for Optimising Load and Haul Operations at Kansanshi Mine, Zambia

Mining of copper and gold at Kansanshi is done in the Main and North West pits using hydraulic excavators and a mining fleet of haul trucks. In the recent past, there has been reduced truck deployment, increased truck and shovel waiting time, reduced production and reduced grade/quality of ore delivered to crushers. Therefore, there is need to improve productivity and optimise operations in mining, loading and hauling. This paper focuses on the use of High Precision Mining (HPM) through use of Wenco’s dispatching algorithm to achieve the best utilisation of all mining equipment and maximise production. The study involved establishing the precise bucket positioning, production rates, cycle times and monitoring the material type and quality /grade of ore delivered to the crushers. This was done by using BenchManager which relies on the motion of the Global positioning System (GPS) antenna scribing an arc as the excavator is rotated to determine the equipment’s centre of rotation by placing the bucket with the teeth flat on the ground (anywhere) and taking the rover and measuring left and right tooth on the outside of the teeth and taking note of the coordinates, first eastings then northings and lastly the elevation. With the tolerance of X=0.5m, Y=0.5m and Z=0.5m, it was noted that the events of a bucket mining out of the assigned polygon were reduced to about 50cm in distance from 34% to 15% and from 10% to 8% in terms of mismatches. The use of precision mining has led to reduced mining cost of about 10.3$/BCM, improved fleet/production reporting, high grade of the material delivered to the crushers of about 75% from the previous 65%. These results indicate that there is a strong business case for implementation of a Wenco fleet monitoring and dispatch system at the mine

The usability of a novel mobile augmented reality application for excavation process considering safety and productivity in construction

PurposeThis study aims to assess the usability of augmented reality (AR) based mobile app for excavation and earthmoving processes using a novel tool entitled Excavator Augmented Reality (EAR).Design/methodology/approachA mixed-methods research approach was used through conducting experimentation to collect qualitative and quantitative data collected from the Sri Lankan construction sector. EAR app was used for experimentation in outdoor areas examining how a 360° tracked hydraulic excavator can be navigated in different physical environments similar to the real prospected job.FindingsThe findings reveal that EAR could make a considerable impact on enhancing productivity, safety and training processes. However, the developed EAR App subjected to assessment demonstrated the highest satisfaction gap for the auditory aspects. Among the remaining criterion, the satisfaction met user expectations for comfortability and no-risk practice. An analysis of strengths, weaknesses, opportunities and threats (SWOT analysis) conducted revealed that visualising the excavator activities and the requirements of improved features were the highest agreed strengths and weaknesses of the EAR. Among the opportunities for improvement, the necessity of improving emergency and safety reached the highest agreement. Moreover, the study presented the challenges in introducing mobile augmented reality (MAR) to the construction sector under the political, economic, sociocultural, technological, environmental and legal (PESTEL) model along with solutions to be taken.Originality/valueThis study provides a novel approach to addressing the safety, productivity and training concerns in heavy mobile plants and machinery on construction sites which remains to be unexplored to this end.

SUBSTANTIATION OF BULLDOZER-EXCAVATOR-AUTOMOBILE COMPLEX FOR REMOVAL OF OVERBURDEN LAYER OF FLUVIOGLACIAL DEPOSITS IN THE CONDITIONS OF SOSNIVSKY GRANITE DEPOSIT

Purpose and task. The aim of the research is to substantiate the expediency and efficiency of using a bulldozer-excavator-automobile complex with the use of ripper bulldozers to remove the overburden layer of fluvioglacial deposits in the conditions of the Sosnivsky granite deposit. To achieve this goal, it is necessary to: establish the patterns of distribution and features of fluvioglacial deposits; to analyze possible technological schemes of development of gravel and sand deposits; justify the need and effectiveness of the technological complex of equipment for the removal of fluvioglacial deposits in the quarry; to establish the dependence of the variable productivity of the excavator on the average size of the piece of rock. Research methods. An integrated approach was used to solve the set tasks: analysis and generalization of previous research on the peculiarities of fluvioglacial deposits and the possibility of using equipment complexes for the development of gravel and sand mountains; technological substantiation of the offered engineering and scientific decisions; analytical calculation of variable productivity of the excavator depending on the average size of a piece of rock. Scientific novelty. The possibility of using a bulldozer-excavator-automobile complex of equipment for removing the overburden layer of fluvioglacial deposits in rock quarries has been substantiated. The analytical dependence of the change in excavator productivity on the average piece size of fluvioglacial deposits is obtained. Conclusions and practical significance. It is established that when the average size of gravel-sand material changes from 20 to 200 mm, the productivity of the excavator decreases by 1,59 times. It is proved that the productivity of the excavator type "straight shovel" is 17% higher than the productivity of the backhoe excavator. For the conditions of the Sosnivsky granite deposit quarry, where the weighted average size of a piece of fluvioglacial sediment is 171 mm, the variable productivity of the excavator is: according to the first technological scheme (hydraulic backhoe excavator placed on the roof of the sediment) – 474,1 m3/shift; according to the second technological scheme (excavator "straight shovel" is located on the lower production horizon) – 553,1 m3/shift. Keywords: fluvioglacial deposits, quarry, technological schemes, equipment complex, excavator productivity, gravel-sand rocks.

Failure Analysis on Tube Arm Cylinder Hydraulic Excavator

The Failure on tube rod arm cylinder hydraulic excavator caused to lose production and processing time on mining site. Investigation included visual inspection, chemical analysis, metallography analyze, and microhardness test. Tube material used high silicon material type while the standard used ST52 carbon steel type. The tube was broken and crack to several pieces. The chemical composition of the tube has different in sulfur and silicon content. From hardness test with micro hardness method, sample tube broken has lower hardness compared to standard hardness. Metallography analysis obtained the phase of tube has same phase with standard which is ferrite and pearlite phase but has different grain size. Based on this study, it can be resumed failure on tube is because impurities and different specification on raw material.

Downsizing the electric machines of energy-efficient electro-hydraulic drives for mobile hydraulics

The poor energy efficiency of state-of-the-art mobile hydraulics affects the carbon dioxide released into the atmosphere and the operating costs. These crucial factors require urgent improvements that can be addressed by the electrification of fluid power. This approach has already generated electro-hydraulic drives that remove flow throttling and enable energy recovery. However, the entire power managed by the actuators of conventional systems must pass through the electric machines. This characteristic is unfeasible for medium-to-high power applications since they need electric motors and electronics with high power ratings and large onboard generation of electricity. Thus, this paper applies to a hydraulic excavator’s boom the idea of splitting the power being transferred to/from the actuator between the hydraulic and electric domains (i.e., a centralized hydraulic power supply is involved). The objective is downsizing the power rating of the boom’s electric components while maintaining the high-power output of the hydraulic actuator. The results show the expected behavior of the hybrid excavator in terms of motion control, but only 57% of the boom’s peak power is now exchanged electrically. The resulting electric machine with 61% downsizing favors the system’s cost and compactness supporting the electrification process that is aligned with the low-carbon economy.

Intelligent prediction for digging load of hydraulic excavators based on RBF neural network

Traditional modeling methods for digging load of excavators are often computationally expensive and require prior knowledge of soil parameters, which severely limits their engineering applications. According to the digging load characteristics in typical digging tasks, this paper presents an intelligent prediction method for digging load based on radial basis function (RBF) neural networks. The recursive least-squares (RLS) algorithm is used for weights updating. Back propagation neural network (BPNN), coupled discrete element method (DEM) and multi-body dynamics (MBD) simulation, and analytical model are applied for comparative studies. The simulation results illustrate that the RBF neural network model outperforms other comparative models in terms of prediction accuracy and computational cost. The hardware-in-loop (HIL) experiments are conducted to validate the proposed approach. Experimental results demonstrate that the error in the dynamic behavior of the excavator under the predicted digging load is less than 7%. This paper lays the foundation for digging load prediction in intelligent excavators.

Анализ методик расчета производительности карьерных гидравлических экскаваторов

The productivity of mechanical and hydraulic excavators is the main indicator characterizing the efficiency of their operation and a tool for planning all kinds of works, in which excavators are involved. There is a considerable quantity of techniques to calculate the productivity of mining machines; despite their general similarity and subordination to the same trend, there are many discrepancies which prevent the use of one or another technique as a universal one or creation of such on its basis. Basically, these discrepancies concern the correction coefficients, characterizing the excavator operating modes. When calculating the technical, and even more, the passport capacity, the methods of their calculation are more or less the same, and certain generalizations can be made about the genesis of a particular factor, but the operational performance is a completely different matter. In this paper, the authors analyze the methods of calculating the capacity of excavators according to the manuals of some foreign manufacturers, as well as reference books on mining. Some discrepancies both in the methods themselves and in the mining terminology are established; priority measures for the elimination of the identified shortcomings are proposed.The current situation in the field of software shows the other side of globalization, which, in fact, has led to monopolization of the Russian market by the Western software companies. The solution to this problem is the transition to domestic software. And this is not only the task of the state, but also that of enterprises interested in the stable functioning of their industries and the growth of qualifications of their employees, because domestic developers rely primarily on the knowledge and experience of Russian specialists, involving them in the innovation process.

Core components-oriented modularisation methodology for complex products

ABSTRACT As a cost-saving and environmental-friendly product strategy, modular design is an effective approach to shorten lead-time and reduce cost for development of products. However, the modular design of products with complex structure might be plagued by the difficulty of product structure modeling and unreasonable structural modular schemes. In this study, a core components-oriented modularisation method is presented to solve the problem of module division of complex products. The structural model of complex products is reasonably simplified by screening core components, which further reduces the modeling difficulty and improves the solution efficiency of module division scheme. Firstly, a hybrid structure decomposition method is proposed to obtain all components of complex products according to the different structure characteristics of each subsystem of complex products. Secondly, the core components of complex products are screened by calculating the whole life cycle cost (WLCC) of each component, and the design structure matrix (DSM) model of complex products is established according to the relationship between the core components. Finally, the module division scheme of complex products is obtained via hierarchical clustering and modularity evaluation. Effectiveness and robustness of the method are demonstrated through comparison experiments for the modular design of a hydraulic excavator case.

Soil-Adaptive Excavation Using Reinforcement Learning

In this letter, we present an excavation controller for a full-sized hydraulic excavator that can adapt online to different soil characteristics. Soil properties are hard to predict and can vary even within one scoop, which requires a controller that can adapt online to the encountered soil conditions. The objective is to fill the bucket with excavation material while respecting machine limitations to prevent stalling or lifting of the machine. To this end, we train a control policy in simulation using Reinforcement Learning (RL). The soil interactions are modeled based on the Fundamental Equation of Earth-Moving (FEE) with heavily randomized soil parameters to expose the agent to a wide range of different conditions. The agent learns to output joint velocity commands, which can be directly applied to the standard proportional valves of the real machine. We test the controller on a 12-ton excavator in different types of soils. The experiments demonstrate that the controller can adapt online to changing conditions without the explicit knowledge of the soil parameters, solely from proprioceptive observations, which are easily measurable.

Research on the matching characteristics of the theoretical digging force of a backhoe hydraulic excavator

The theoretical digging force is the maximum digging resistance that an excavator can overcome, which is an important measure of its digging capacity. To study the matching of the digging capacity with the actual demand and the matching of the working device mechanism, a 36.5 t backhoe hydraulic excavator is used as an example to analyse the distributions of the digging resistance under two different normal digging area working conditions and the maximum digging resistance characteristics of the tool. An appropriate digging postures are selected, based on limit digging force and compound digging force models, the theoretical digging forces under the two working conditions are obtained and matched with the measured digging resistance force values and the limiting factors affecting the digging force. The results show that the average percentage of theoretical digging forces greater than the measured digging resistance under both calculation models is 84.06% rather than 100%. The results of different digging methods all indicate that small chamber locking of the boom cylinder is too often the limiting factor for the digging force, resulting in poor matching of the working device. This study provides guidance for the improvement of the theoretical digging force model and the evaluation of the matching characteristics of the working device.

ცნებებისა და განმარტებების შეუსაბამობა

The Palitra-L Publishing House translated the Great Visual Encyclopedia into Georgian and published it, in the presentation of which we read that "part of the terms and definitions have been changed with new ones, the meaning of some has increased. It is possible to check the meaning of a specific word by checking relevant illustration" – say the authors of the book, who gathered specialists in terminology, linguists, scientists when creating the encyclopedia. It would be better if the publishing house had invited the relevant specialists of the field as well. The part of the Georgian translation of the encyclopedia that I consider in the article (Book 4, Chapters XVII and XVIII) does not seem to have been reviewed by the appropriate specialists of the field and technical terminology. Moreover, the terms and definitions used in the illustrations are not related and completely inconsistent with their functional purpose. Chapter XVII, Trucks, considered: dumping truck; cranes; container, etc. Chapter XVIII, Robust Mechanisms, considered: bulldozer; wheeled loader; hydraulic excavator; scraper; grader; land roller, etc. Obviously, the question arises as to the meaning of the term Robust and why it does not combine a particular mechanism, even trucks. Most of the concepts, terms and definitions used in the translation differ from the concepts and terms adopted and established in Georgian technical terminology, and their inconsistency is obvious. Also, captions for illustrations are often grammatically and meaningfully incorrect and absurd. For example, according to the Georgian translation of the encyclopedia, the blade -"lapoti" in the bulldozer is a "metal concave device", and in the scraper – "bowl, ladle, hopper". In fact, the bulldozer is equipped with dozer blade, while the scraper is equipped with a bucket, and the term blade – "lapoti" is not found at all in Georgian technical terminology. For example, "hook – a piece of hard metal", as well as "gooseneck connection" and others. The fact that hook is not a piece of metal does not require any special education, as for the "gooseneck connection" – it is a complete curious thing. I would recommend translators of the above discussed sections of the encyclopedia to use the explanatory dictionary of “Hoist transport, road construction machines and equipment" published by us as well as the existing Georgian technical terminological dictionaries.

A Study on Trajectory Control System of Hydraulic Excavators Based on Multi-Domain Physical Model*

Hydraulic excavators are complex mechatronics construction machinery with characteristics of multidiscipline intersection and multi-domain close coupling. To analyze the comprehensive property of its trajectory control system, a method of multi-system hybrid modeling and simulation based on MATLAB is proposed and described. In this paper, the multi-domain physical model of a medium-sized hydraulic excavator is established. The considered model is mainly comprised of four other subsystems: a machine system, a hydraulic system, a trajectory control system and a sensor system. Moreover, a fuzzy neural network (FNN) PID strategy is introduced to the trajectory control system to guarantee the accuracy of automatic operation. On the basis of the multi-domain physical model, typical simulation experiments for working patterns were performed to validate the performance of the FNNPID controller. Comparison results demonstrate that the precision and velocity response of the FNNPID controller is better than that of the PID with traditional algorithm. The tracking errors of the boom, the arm, the bucket and the swing are decreased by 3∘, 3.2∘, 5.5∘ and 7.5∘, respectively. Establishment of the multi-domain physical model offers technical means for optimization design and rapid modeling of the complex electromechanical system.

Modeling and Simulation of Theoretical Digging Force of an Excavator Based on Arbitrary Posture

Theoretical digging force is an important performance parameter of the hydraulic excavator. Due to the multi-linkage mechanism, the digging posture of an excavator is ever-changing; thus, it is not easy to calculate the theoretical digging force. Traditionally, the theoretical digging force is calculated by selecting a limited number of postures of the excavator based on experience, which cannot reflect the force condition of each posture in the excavation process. In order to calculate the theoretical digging force of any posture in the excavation process, this paper uses the principle of the analytical method to establish a theoretical excavation force mathematical model of bucket excavation and uses Matlab software to solve the theoretical excavation force mathematical models. In order to verify the model’s correctness, the experimental method is used to determine the actual maximum excavation force of the excavator. The test results showed that there was little difference between the actual maximum digging force and the theoretical maximum digging force, which verified the correctness of the theoretical digging force mathematical models and provided a theoretical digging force calculation method and reference for the structural design and optimization of the excavator.

Dynamic Modeling of a Hydraulic Excavator Stick by Introducing Multi-Case Synthesized Load Spectrum for Bench Fatigue Test

A multi-case load spectrum compiling method is proposed in this study for dynamic modeling of a hydraulic excavator stick to simplify and accelerate the fatigue bench test. This new method includes a simplified criterion of small-load-omitting threshold based on the principle of invariable fatigue damage, an extreme value inference criterion based on the overflow characteristics of the hydraulic system, and a synthetic extrapolation method under various working conditions. Firstly, a one-dimensional spectrum of a medium-sized excavator stick was compiled. Then, the program load spectrum for the bench fatigue test was obtained by modifying the one-dimensional spectrum based on the damage consistency criterion and the damage equivalent principle. Lastly, the fatigue tests were conducted using the program load spectrum, as well as using the random spectrum. The comparison results demonstrate that the damage location and fatigue life distribution of the stick using these two spectra are generally consistent, with a relative error smaller than 8.8%; however, the proposed program load spectrum can accelerate the test process with less time consuming than that of the random spectrum. As a result, the multi-case load spectrum is feasible and reliable for dynamic modeling of the hydraulic excavator stick in practice.

An Adaptive Robust Impedance Control Considering Energy-Saving of Hydraulic Excavator Boom and Stick Systems

In this article, taking the hydraulic system of mining hydraulic excavator boom and stick as the plant, an adaptive robust impedance controller based on an extended state observer and backstepping method is designed. The energy-saving operation and position tracking performance are considered in system modeling and control law design. The system effects on electro-hydraulic proportional valves with open centers and flow regeneration valves (FRVs) are considered. When hydraulic cylinders are extended, the proposed control strategy adopts a pump-controlled pressure closed-loop to shorten the dead time. When hydraulic cylinders are retracted, less oil is output to meet the idle demand. The valve-controlled position subsystem with impedance mode ensures smoother digging processes. Comparative simulations show that the proposed control strategy has better position tracking and smaller velocity fluctuations. Compared with the system without FRVs, the proposed system can reduce energy consumption by 27.32%.