Boom Cylinder Research Articles

Mitigating Measurement Inaccuracies in Digital Twins of Construction Machinery through Multi-Objective Optimization.

The advent of digital twins facilitates the generation of high-fidelity replicas of actual systems or assets, thereby enhancing the design's performance and feasibility. When developing digital twins, precise measurement data is essential to ensure alignment between the actual and digital models. However, inherent uncertainties in sensors and models lead to disparities between observed and predicted (simulated) behaviors. To mitigate these uncertainties, this study originally proposes a multi-objective optimization strategy utilizing a Gaussian process regression surrogate model, which integrates various uncertain parameters, such as load angle, bucket cylinder stroke, arm cylinder stroke, and boom cylinder stroke. This optimization employs a genetic algorithm to indicate the Pareto frontiers regarding the pressure exerted on the boom, arm, and bucket cylinders. Subsequently, TOPSIS is applied to ascertain the optimal candidate among the identified Pareto optima. The findings reveal a substantial congruence between the experimental and numerical outcomes of the devised virtual model, in conjunction with the TOPSIS-derived optimal parameter configuration.

The design and analysis of a hydro-pneumatic energy storage closed-circuit pump control system with a four-chamber cylinder

A decentralized variable electric motor and fixed pump (VMFP) system with a four-chamber cylinder is proposed for mobile machinery, such that the energy efficiency can be improved by hydro-pneumatic energy storage, and problems of closed-circuit pump-controlled systems including asymmetrical flow and speed limitation are addressed. One of the chambers is arranged to the energy storage accumulator to increase energy efficiency, while the other chambers are flexibly connected to the pump ports to achieve variable transmission ratios. The piston areas of the multiple chambers are designed at first to permit a symmetric single-rod cylinder, and secondly a switching system with three operating modes is presented to expand force-velocity capabilities. Then, the four-chamber cylinder system with three solenoid valves is designed to substitute for the traditional two-chamber boom cylinder in a 6-ton excavator. A valve switching logic, as well as a feedforward and feedback compound speed controller, are presented. Simulations conducted in a 6-ton excavator model show that the maximum velocity increases by 66 %, together with asymmetrical flows to diminish the low-pressure charging accumulator. Peak power and energy consumption are both reduced by more than 20 % compared with the VMFP using the two-chamber cylinder. The energy-saving characteristics of the 6-ton excavator are emphatically analyzed considering energy storage and re-utilization. At last, experiment verifications are conducted in a lifting mechanism to verify the proposed energy-storage system.

Innovative powertrain and advanced energy management strategy for hybrid hydraulic excavators

This paper presents an innovative powertrain managed by an advanced energy management strategy for hybrid hydraulic excavators to improve the overall energy efficiency. Here, a main pump is driven via a planetary gear by an engine and an electric motor/generator. A double clutch is integrated to adjust torque and speed of engine according to efficiency map enabling higher working efficiency. Potential energy of the boom cylinder can be converted and stored in a battery through an energy regeneration system. The advanced energy management strategy is designed by utilising extremum seeking and fuzzy techniques to optimally distribute power requirement. A fuzzy logic system is designed based on consideration of battery performance and aging to adjust a penalty function subsequently improving the overall system performance while prolonging the component lifetime. Simulations and real-time experiments have been carried out to evaluate the effectiveness of the proposed powertrain managed by the advanced energy management strategy.

An electrified boom actuation system with energy regeneration capability driven by a novel electro-hydraulic unit

This paper presents a novel electrified solution for linear actuation systems, which has undergone a successful in-vehicle demonstration, marking a significant advancement in this field. Aligned with the growing trend towards electrification, this solution holds promise for a wide range of off-road applications. The showcased electro-hydraulic actuation architecture enables efficient four-quadrant operation and incorporates energy recovery capabilities. At the core of the system lies a distinctive electro-hydraulic unit, integrating a fixed hydraulic pump and a variable-speed electric motor into a compact and powerful entity. A specialized hydraulic system is designed to efficiently transform electrical energy from the electro-hydraulic unit into boom cylinder actuation. The sizing of the system is determined by the boom operation of a commercial compact loader. The maximum power output of the electro-hydraulic system is approximately 15 kW. The components of the proposed system are integrated into the reference vehicle, and comprehensive performance tests are conducted. The results of the tests performed on the vehicle with the boom lifting and lowering cycle indicate an overall system efficiency of 60%. The electrified solution consumes only about one-third of the energy used by the conventional boom actuation system on the reference machine, while exhibiting energy savings exceeding 75% during specific work phases. The energy savings come mainly from energy regeneration and minimal loss from throttling through the specialized hydraulic circuit design. The successful demonstration on the reference vehicle underscores the practicality and effectiveness of the proposed electrified solution in current mobile hydraulic applications.

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.

Analisis Kerusakan Sistem Hidrolik pada Boom Silinder Unit Eskavator Komatsu PC 200-7 di PT. Wirato Mitra Mulia

Boom cylinder is a component of the excavator which is located on the left and right front. This component works to move the bucket optimally by utilizing hydraulic oil flow. Boom cylinders will experience a decrease in performance if there are problems and damage to their internal parts. This Scientific Paper Analysis collects data from various direct observations in the field and makes improvements to the tools. boom cylinder malfunctions get information from the chief maintenance mechanic and experienced mechanics. This can be a basic problem of analysis, performance disturbances in the boom cylinder components can be caused by several factors, one of which is contamination that occurs in the boom cylinder. there is no inside and outside, and the occurrence of overheating in the boom part of the cylinder components. The causes of damage to the cylinder boom are very diverse, this can occur due to certain factors, including the use of the unit by the operator, steep work terrain and many other determining factors that damage the components of this cylinder boom. The problem of thinning the cylinder boom can be carried out according to procedures, capacity that is not excessive according to work standards, and daily, daily and monthly maintenance.

Numerical Analysis of Energy Recovery of Hybrid Loader Actuators Based on Parameters Optimization

The conventional loader actuator hydraulic system suffers from the potential energy waste problem of the boom arm. This study proposes a hydraulic control method and control strategy for the energy recovery and regeneration of a hybrid loader arm. When the boom arm drops, the piston side of the boom cylinder charges the accumulator, and the system achieves energy recovery. When the boom arm rises, the accumulator releases hydraulic energy to drive the energy regeneration hydraulic motor to provide energy for the system, and the system achieves energy regeneration. The system’s principle analysis and the mathematical model are completed based on Boyle’s, Newton’s second law, and the flow continuity principle. The simulation model is established using AMESim 2D mechanical library, HCD library, and signal library. Under the typical working condition, 50-type wheel loader numerical simulation research is conducted, and the system cylinder motion characteristics, accumulator charging and discharging performance, system energy recovery, and regeneration performance are obtained. On this basis, energy recovery and regeneration efficiency are selected as optimization objectives. The optimal designs of accumulator and energy regeneration hydraulic motor parameters are carried out to obtain the influence law of accumulator and hydraulic motor parameters on system energy recovery and regeneration, and the energy-saving effect of the system is analyzed. The results show that the optimized parameters effectively improve the system energy recovery and regeneration efficiency and reduce engine fuel consumption. The system provides a reference for designing an energy recovery system and researching the energy-saving technology of loaders.

Prediction and verification for the models of temperature rising by medium bubbles in hydraulic system

In order to obtain the influence of the medium bubble contents on temperature rising characteristics of a hydraulic system, the working hydraulic system of a wheel loader was taken as the research object. By carrying out the comparison experiments of the hydraulic system with and without de-aeration devices on a 5-ton wheel loader, the air bubble contents and concerning temperatures were obtained. To identify the factors which have impact on temperature rising of the hydraulic system, the head chamber of boom cylinder is taken to analyze, and the temperature rising expression in a volume were deduced. By the utilization of the thermal hydraulic library, combining with mechanism and control libraries on AMESim simulation platform, the integrated simulation model of the whole system was established and verified, meanwhile, the simulation was carried out from aspects in different air contents and initial chamber temperatures. From the simulation, the prediction models of the air contents to temperature rising, and the pressures to temperature rising were predicted. Finally, the correctness of the prediction models are verified by experiment data and showing good results, which can be used to enrich and improve the calculation and evaluation methods of heat generation to any other hydraulic systems.

A Study on a New Independent Metering Valve for Hydraulic Boom Excavator

Nowadays, hydraulic excavators are an indispensable part of the construction industry; however, conventional hydraulic excavators consume a great deal of fossil fuel and release a large amount of pollution emissions into the environment. This causes many unwanted costs, therefore, effective solutions are required to solve the above-mentioned problems. In this paper, a new independent metering system is proposed to improve energy-saving and reduce costs of a conventional system. In detail, a directional valve is used to control movement and three electro-hydraulic poppet valves are integrated to adjust the flow rate at the inlet and outlet ports of the boom cylinder. In addition, a control strategy based on the coordination between the speed of the pump and the opening area of the spool valve is designed to improve the performance of the system. Specifically, the valves are controlled based on the strategy that the meter-in valve is opened fully to reduce throttling losses and that the meter-out valve is controlled to reduce leakage. The speed of the pump is adjusted according to the feedback position signal. To demonstrate the effectiveness of the new configuration, a real test bench of the boom system was built under laboratory conditions. From the experimental results, the new independent metering valve system not only works with a high tracking precision, but it also reduces energy consumption. Compared with a conventional independent metering system, the fuel economy of the proposed structure can achieve a reduction of approximately 6.5%.

Field Setup and Assessment of a Cloud-Data Based Crane Scale (CCS) Considering Weight- and Local Green Wood Density-Related Volume References

When investigating the forwarding process within the timber supply chain, insufficient data often inhibits long-term studies or make real-time optimisation of the logistics process difficult. Information sources to compensate for this lack of data either depend on other processing steps or they need additional, costly hardware, such as conventional crane scales. An innovative weight-detection concept using information provided by a commonly available hydraulic pressure sensor may make the introduction of a low-cost weight information system possible. In this system, load weight is estimated by an artificial neural network (ANN) based on machine data such as the hydraulic pressure of the inner boom cylinder and the grapple position.In our study, this type of crane scale was set up and tested under real working conditions, implemented as a cloud application. The weight scale ANN algorithm was therefore modified for robustness and executed on data collected with a commonly available telematics module. To evaluate the system, also with regard to larger sample sizes, both direct weight-reference measurements and additional volume-reference measurements were made. For the second, locally valid weight-volume conversion factors for mainly Norway spruce (Picea abies, 906 kg m-3, standard error of means (SEM) of 13.6 kg m-3), including mean density change over the observation time (–0.16% per day), were determined and used as supportive weight-to-volume conversion factor.Although the accuracy of the weight scale was lower than in previous laboratory tests, the system showed acceptable error behaviour for different observation purposes. The twice-observed SEM of 1.5% for the single loading movements (n=95, root-mean-square error (RMSE) of 15.3% for direct weight reference; n=440, RMSE=33.2% for volume reference) enables long-term observations considering the average value, but the high RMSE reveals problems with regard to the single value information.The full forwarder load accuracy, as unit of interest, was observed with an RMSE of 10.6% (n=41), considering a calculated weight-volume conversion as reference value. An SEM of 5.1% for already five observations with direct weight reference provides a good starting point for work-progress observation support.

Investigation into the Independent Metering Control Performance of a Twin Spools Valve with Switching Technology-controlled Pilot Stage

In hydraulic area, independent metering control (IMC) technology is an effective approach to improve system efficiency and control flexibility. In addition, digital hydraulic technology (DHT) has been verified as a reasonable method to optimize system dynamic performance. Integrating these two technologies into one component can combine their advantages together. However, few works focused on it. In this paper, a twin spools valve with switching technology-controlled pilot stage (TSVSP) is presented, which applied DHT into its pilot stage while appending IMC into its main stage. Based on this prototype valve, a series of numerical and experiment analysis of its IMC performance with both simulated load and excavator boom cylinder are carried out. Results showed fast and robust performance of pressure and flow compound control with acceptable fluctuation phenomenon caused by switching technology. Rising time of flow response in excavator cylinder can be controlled within 200 ms, meanwhile, the recovery time of rod chamber pressure under suddenly changed condition is optimized within 250 ms. IMC system based on TSVSP can improve both dynamic performance and robust characteristics of the target actuator so it is practical in valve-cylinder system and can be applied in mobile machineries.

Flywheel-Based Boom Energy Recovery System for Hydraulic Excavators with Load Sensing System

A hydraulic excavator (HE) is a typical piece of construction equipment and is widely used in various construction fields. However, the poor energy efficiency of HEs results in serious energy waste and has aroused the attention of researchers. Furthermore, rising fuel prices and increasing stringent waste gas emission legislation sparked demand for ways to improve energy efficiency. Recovering the otherwise wasted boom potential energy of a conventional HE by proper methods offers the potential to improve the fuel efficiency of HEs. In this paper, a mechanical energy recovery system consisting of a pump/motor and a flywheel is presented for HEs using a load sensing system. When the boom moves down, the boom potential energy is converted into mechanical energy by the boom cylinder and the pump/motor to accelerate the flywheel. When needed, the captured energy stored in the flywheel is converted back into a form of pressure energy to directly drive the boom cylinder up without throttling the main valve. In the lifting process, a compound circuit that consists of a throttling control circuit and a displacement control circuit is presented. A control strategy is proposed to optimize the energy recovery and reuse procedure. A 4-t HE is used as a study case to investigate the energy-saving potential of the proposed system. Numeric simulations show that the proposed system, when compared with a conventional load sensing system, can reduce as much as 48.9% energy consumption in a non-loaded cycle of boom lifting and lowering process. As to a fully loaded case, the energy-saving rate is 16.9%. This research indicates the flywheel-based scheme is promising for developing an energy-efficient fluid power system for HEs and reducing energy consumptions.

버킷 위치 제어용 입력성형기에 관한 연구

To perform work of unmanned excavator, such as leveling, stumping and digging, working paths had to generate and motion of bucket had to follow this generated paths. However the motion of bucket had moved like undamped system when bucket was far from the body of excavator. In this condition, the movement of bucket couldn’t follow the suggested path easily due to relatively huge mass and spring constant. To adjust the path of bucket, the unmaned excavator needs extra controller that can control a displacement of the bucket with feed back signal. However, this solution requires extra cost and it also increases energy loss to control itself. An input shaper is a feed forward controller that can reduce the residual vibration with reference input modification. This controller doesn’t need any extra equipment and energy that improve the performance of the system. However, hydraulic cylinder system still has problem where it has a huge difference between natural frequency of the system and frequency response of actuator. Indeed, hydraulic actuator is too slow to use an input shaperBR The purpose of this paper is to suggest an input shaper that can import a hydraulic system. To satisfy this purpose, at first, kinematics and inverse kinematics of the excavator was induced. The position of the bucket was controlled by hydraulic cylinders which can be assumed like 3-axis robot. This mechanical analysis can be used to set up the command signal. After that, an input shaper was designed to reduce the residual vibration. A boom cylinder has residual vibration when bucket cylinder was moved despite a damping effect of this system. A residual vibration can be assumed a second order system and it can be adjusted by an input shaper. This result was compared with path trajectory on a fifth order polynomial. After that, the suggested input shaper was induced from the principal of the input shaper. Consequently, the suggested input shaper was verified with computer simulation.

A Boom Energy Regeneration System of Hybrid Hydraulic Excavator Using Energy Conversion Components

In this paper, a novel design of an energy regeneration system was proposed for recovering as well as reusing potential energy in a boom cylinder. The proposed system included a hydraulic pump/motor and an electrical motor/generator. When the boom moved down, the energy regeneration components converted the hydraulic energy to electrical energy and stored in a battery. Then, the regenerated energy was reused at subsequent cycles. In addition, an energy management strategy has been designed based on discrete time-optimal control to guarantee position tracking performance and ensure component safety during the operation. To verify the effectiveness of the proposed system, a co-simulation (using MATLAB and AMESim) was carried out. Through the simulation results, the maximum energy regeneration efficiency could achieve up to 44%. Besides, the velocity and position of the boom cylinder achieved good performance with the proposed control strategy.

Dynamic Simulation of a Hydraulic Excavator to Determine the Joint Reaction Forces of Boom, Stick, Bucket, and Driving Forces of Hydraulic Cylinders

To optimize the dimensions of the boom, stick of the hydraulic excavator and select the suitable hydraulic bucket, stick, and boom cylinders, the designer must determine the joint reaction forces and driving forces. These forces always alter in an excavator's working cycle. They are conventionally calculated by mathematical method. This conventional method is complicated and challenging to determine the maximum reaction forces, which can break the stick and boom. This article builds a 3D model and simulates a working cycle of the hydraulic excavator to find the reaction force diagrams of boom and stick as well as driving forces of hydraulic cylinders by using computer software PTC Creo Parametric. Based on these results, the designer easily calculates the maximum tensions of the dimensions of boom and stick in a working cycle to optimize their dimensions as well as selects suitable hydraulic cylinders.

Remanufacturability evaluation method and application for used engineering machinery parts based on fuzzy-EAHP

Remanufacturing is an important mode to promote the sustainable development of manufacturing industry. Remanufacturing mechanical components at the best recycling time can effectively reduce the remanufacturing cost and improve the remanufacturing efficiency. Therefore, the decision-making model of optimal recycling time based on full lifecycle assessment and full lifecycle cost method was firstly established to analyze and model the energy consumption, cost and emission of components in the original manufacturing, usage, remanufacturing and reuse stages. Then, a remanufacturing evaluation method based on fuzzy extension analytic hierarchy process was proposed. Considering a variety of uncertainties of waste components, a qualitative and quantitative evaluation index system was established, and the weight of each evaluation index was determined by expert evaluation and fuzzy comprehensive evaluation method. Finally, a boom cylinder of a concrete pump truck was studied. The boom cylinder recovered by the method proposed has a high recovery value, and its comprehensive score reaches 70, which verifies the effectiveness and superiority of the model.

Performance enhancement of hybrid hydraulic excavator using multiple hydro-pneumatic accumulators

In this article, the heavy earth moving machinery like hydraulic excavator used in the construction and mining industries has been taken into consideration. Most of the heavy earth moving machineries used in these industries are mobile with engine as the main source of power. The work deals with two different hydraulic circuits: first the proposed one and second the conventional one, and both are studied at laboratory scale, which resembles the circuit of the hydraulic excavator. In the hydraulic circuit, out of the three hydraulic linear actuators, two are connected with hydro-pneumatic accumulators and one hydro-motor is also taken into consideration, which resembles the boom, arm, bucket and swing motor, respectively. The idea behind the proposed circuit is to store substantial potential energy during downward movement of the two linear actuators in the accumulators, which resembles the boom and arm cylinder of the excavator. The stored energy is used for upward motion of the two actuators without utilizing any energy from the main pump. For the devised strategy, MATLAB/Simulink environment has been utilized for developing the simulation model and the same has been validated with the experimental data with reasonable accuracy. The effect of accumulator volume and pre-charge pressure has been studied for optimization of the accumulator size on the validated simulation model. This concept helps in saving 14.06% energy than its conventional counterpart which does not have the energy storage elements. The linear position control of the boom and the arm actuator in the proposed circuit have been accomplished using proportional–integral–derivative control and pressure-compensated proportional flow control valve and have been achieved with reasonably accuracy.

Intelligent energy-saving operation of wheel loader based on identifiable materials

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.

Potential energy recovery method based on alternate recovery and utilization of multiple hydraulic cylinders

The working device weight of hydraulic excavators far exceeds that of its lifted material, requiring a large amount of energy to maintain the frequent motion of lifting and lowering. Recovering and utilizing this energy is an effective means of energy-saving for excavators. The existing electric recovery method faces disadvantages which include excessive energy conversion, a complicated system, and high cost. In this paper, an energy alternate recovery and utilization system (EARUS) based on multiple hydraulic cylinders is proposed. The concept of weight-balanced is applied to match the weight of the working device with the pressure of the hydraulic accumulator. Energy alternate recovery and utilization are realized in different hydraulic cylinders, so that the weight-balanced circuit and the original system perform the necessary oil exchange, overcoming the reliability problem of the existing isolated weight-balanced system with long-term operation. The efficiency of EARUS is comprehensively analyzed through simulation and an experiment using the methodology of energy flow decomposition. The working device motion characteristics of EARUS are then quantitatively analyzed. Results show that, compared with the original system, the energy recovery efficiency of EARUS is 65.9%, and the comprehensive energy-saving rate is 41.6%. The boom single-action time is shortened by 2.6 s, and the velocity fluctuation of the boom cylinder at the start of lowering decreases by 75%. The research findings provide an important framework for the engineering applications of this new system.

Skid-Proof Operation of Wheel Loader Based on Model Prediction and Electro-Hydraulic Proportional Control Technology

Wheel loader shovel loading operation tests showed that when the tire slips, it not only causes waste of the engine power, but also increases the tire wear. In this paper, the regression prediction model is combined with the electro-hydraulic proportional control technology. For the first time, the method of adjusting the posture of the working device is proposed to realize the skid-proof shovel control strategy of the wheel loader. In this control strategy: (1) The electro-hydraulic proportional control technology applied to this wheel loader is introduced. (2) The load spectrum of the wheel loader is analyzed during the shovel loading operation. Moreover, combined with the drive shaft torque, pilot pressure and boom cylinder displacement, the particle swarm optimization-support vector machine (PSO-SVM) algorithm is used to complete the construction of the regression prediction model of the boom cylinder displacement. (3) A controller is designed based on the fractional-order PID control algorithm. The skid-proof control strategy is simulated and verified by constructing the joint simulation model. The corresponding program is prepared in the hydraulic system controller and the effectiveness of the control strategy and algorithm are verified by the wheel loader shovel loading operation.