Electric Loader Research Articles

Investigation of Drive Performance of Motors in Electric Loaders with Unequal Transmission Ratios—A Case Study

Investigation of Drive Performance of Motors in Electric Loaders with Unequal Transmission Ratios—A Case Study

ECOLOGICAL ELECTRIC CAR USABLE IN THE AGRICULTURAL SECTOR

Growing concern of carbon dioxide emissions, greenhouse effects and rapid depletion of fossil fuels raise the necessity to produce and adopt new eco-friendly sustainable alternatives to the internal combustion engine driven vehicles. For this reason, in the last decade, electric vehicles have become in some way widespread, principally because of their negligible flue gas emissions and lesser reliance on oil. Although electric cars were introduced many years ago, agriculture electric vehicles have recently gained attention. The world of agriculture has changed, small-specialized farm utility vehicles are now used for a specific purpose, and in several cases, they have an electric engine. In our research, we focused on the design and preparation of a prototype the variable, multifunctional ecological electric loader, which would be dimensionally adapted to the needs of use in greenhouse, interior growing halls, as a result of research by students of innovative dual technical education with effective support of their teachers. The result of our research was the design and construction of a prototype of a smaller electric loader, which meets demanding quality parameters (performance) and environmental attributes (reduced noise and almost zero emissions) for work in greenhouses.

Working cycle condition construction for electric wheel loader based on principal component analysis and cluster analysis

With the rapid development of new energy technology, cycle condition is significant for the design of powertrain system, whole machine economy, endurance, and other performance parameters of pure electric drive machines. Many cycle conditions of the passenger car industry have been defined. While that for the loader which has complex operation modes and working conditions, has less research on this aspect. Cycle conditions suitable for loader have not been constructed. To support the research and development of electric loader power system, the cycle conditions that can reflect the driving characteristics of electric loader are studied in this paper. According to the typical “V” cycle condition of loader, the actual driving condition data are collected and the kinematic segments are divided. The kinematic segments are grouped into five categories by using principal component analysis and K-means clustering algorithm to obtain the clustering center of each category. The working cycle condition is formed by extracting the combination of segments closest to the clustering center. Finally, based on AMESim simulation and whole machine test analysis, the error between the simulation and vehicle test results of the energy consumption is 3.4%. The accuracy and effectiveness of the proposed constructed cycle conditions are verified.

A real‐time energy management control strategy of hybrid energy system for a pure electric loader

SummaryTo enhance the efficiency and prolong the battery life of hybrid energy systems equipped with battery and supercapacitor for a pure electric loader, this paper proposes a real‐time energy management strategy based on model predictive control (MPC). First, the working characteristics of the loader and the topology structure of the hybrid energy are analyzed. Second, considering the repetitive operation model of electric loaders, a neural network algorithm based on long short‐term memory is used to predict power and a dynamic programming algorithm is used as the rolling optimization solution for MPC strategy. Finally, the MPC is verified using the simulation in MATLAB/Simulink. The results indicate that compared with other strategies, the MPC strategy can improve hybrid energy efficiency and reduce the maximum battery current fluctuations. The proposed method demonstrates the feasibility and effectiveness of the hybrid energy system.

Braking Intention Identification Strategy of Electric Loader Based on Fuzzy Control

As a widely-used construction machinery, the electric loader has the potential to recover braking energy due to its large mass and frequent starts and stops. Identifying braking intention accurately is the foundation of braking energy recovery. The typical braking condition of an electric loader is analyzed; the braking intention is divided into sliding brake, mild braking, moderate braking, and emergency braking. A large number of braking data were collected under different braking intentions, which are used as the basis for fuzzy control variable partitioning, fuzzy controller parameter setting and fuzzy control rule formulation. The control strategies of deceleration intention identification based on accelerator pedal, braking intention identification based on brake pedal and sliding brake intention identification are proposed in this paper, respectively. This paper takes the hydraulic brake pressure as a feedback parameter, even if there is hysteresis or failure based on the intention of pedal identification, the system can still provide sufficient braking strength to ensure the braking safety. The AMESim(R12)-Matlab/Simulink co-simulation model and prototype are built to verify the feasibility of the control strategy under different braking intention identification. The results show that the braking strength under stronger braking intention can satisfy the braking demand whether at a speed of 2 m/s or 12 m/s, which ensures the safety of emergency braking, and the electric loader can provide stable braking strength under different braking intention and different speed. This has good braking stability.

Efficiency Comparison of Electric Wheel Loader Powertrains with Dual Motor Input in Distributed Driving Modes

The presented research on electric wheel loaders lacks a detailed analysis of drive energy-saving during the shovel preparation phase, which is characterized by a high probability of loader tire skidding. To address this issue, this study examines the energy consumption efficiency of a two-motor distributed drive wheel loader under three drive modes including front motor drive, rear motor drive, and dual-motor drive, taking into account the change in the drive force demand caused by the bucket landing. This study finds that the motor energy conversion efficiency is the greatest in single-motor drive mode when the bucket does not generate positive pressure with the ground. In dual-motor drive mode, the total torque overcome is greater, but the motor energy conversion efficiency is the greatest when the bucket generates the greatest positive pressure with the ground. This study suggests that in future designs of electric loaders, two motors can be used to distribute the drive, but the front and rear motors should be designed to participate in the drive with a certain torque distribution ratio at different speeds and resistance to avoid the phenomenon of the bucket pressing the ground too much.

Recovery and Control Strategy of Electro-Hydraulic Composite Braking Energy for Electric Loader with Braking Intention Recognition

The loader has a lot of recoverable braking energy due to its larger mass and frequent starts/stops. For a 5-ton pure electric drive loader, an emergency braking intention recognition strategy based on hydraulic braking pressure was proposed. The braking intention recognition strategy of an acceleration pedal and brake pedal was used to distinguish different braking intentions, and the hydraulic braking system pressure was used as a feedback parameter for emergency braking intention recognition to improve braking safety. Aiming at electro-hydraulic composite braking mode switching, a collaborative control strategy of walking regenerative braking and mechanical braking is proposed. Simulation analysis by AMESim and vehicle test results show that the proposed control strategy can realize driver braking intention recognition and electro-hydraulic braking force distribution under different working conditions and improve braking smoothness. According to the calculation of the energy recovery effect evaluation index, the energy recovery efficiency is up to 71.64%, the braking recovery rate is above 42.50%, and the maximum energy saving for the whole vehicle is 7.58% under one cycle condition. The proposed strategy has a good energy-saving effect.

Electro-Mechanical Modeling and Evaluation of Electric Load Haul Dump Based on Field Measurements

In underground mining, conventional loader equipment uses diesel as a power source, implying different drawbacks, such as combustion gases, low visibility, worker’s health problems, and high ventilation requirements. Thus, hybrid and electric loaders are being developed by the main industry suppliers who prefer clean technology. In this study, we analyzed the performance of an electro-mechanical powertrain through a dynamic model of underground-loader equipment using field data. This electric LHD model was compared to a diesel loader under the same operational conditions. For the case study, the results showed that the proposed electro-mechanical model, considering 14 tons of capacity, consumed 86.8 kWh, representing 60.5% less energy than the diesel loader with similar speed and torque characteristics. Thus, the proposed methodology is a valuable tool for operators, process engineers, and decision-makers, allowing an energy-efficiency evaluation for electric LHD adoption, based on the current operational data available for conventional equipment.

Robust Control for the Hybrid Energy System of an Electric Loader

With the wide application of electric vehicles and the development of battery technology, pure electric construction machinery (PECM) has received more and more attention due to its high efficiency and no pollution. The working conditions of construction machinery are complex and accompanied by periodical working conditions and heavy load. For electric construction machinery, a heavy load represents an energy supply with a large current. To adapt to the working conditions of PECM, this paper proposes a robust controller to regulate the current of the hybrid energy system (HES) which include the battery and supercapacitor. The V-type operating conditions of a 5-ton pure electric loader are the research focus to analyze the working principles of the HES. The topology and energy flow patterns of the HES are proposed and analyzed. The model of the battery, supercapacitor, and DC/DC converter are depicted, and the robust control method is designed. An electric loader experiment platform is created to verify the effectiveness of the robust control method. Compared with the proportional integral control effect, the experiment results show that the proposed control method had good control performance and could better regulate the current. It can be used as a reference value for other dual energy source PECM.

Torque Distribution Control Strategy of Electric Wheel Loader with Multiple Drive Motors Based on Optimal Motor Efficiency

<div>Wheel loaders are widely used in construction projects. In order to reduce pollution and energy consumption, major wheel loader manufacturers are developing electric powertrain technology. Our main research goal is to reduce the energy consumption of a pure electric loader. This study is intended to build a vehicle simulation model of a multiple drive motor electric loader. According to the common working conditions and empirical formulas of the loader, the simulation data of the electric loader are calculated. The torque distribution control strategy based on the optimal efficiency of the motor is designed for the multiple drive motor electric loader and is compared with the equal proportion distribution control and the axle load ratio distribution control through simulation analysis. The simulation results show that the proposed torque distribution control strategy based on motor optimal efficiency can reduce energy consumption by 7–12%.</div>

Simulation Study on Variable Pressure Margin Energy Recovery of Electric Loader Actuator

The conventional electric loader uses a motor instead of an engine, which aligns with the current energy-saving and emission-reduction trend. However, the motor’s speed control performance and overload capacity are under-utilized, and the actuator suffers from the potential energy waste problem of the boom arm. This study proposes a variable pressure margin energy recovery system for the electric loader actuator. It uses a combination of a permanent magnet synchronous motor (PMSM) and a quantitative pump. It can achieve variable pressure margin control and energy recovery through the pressure feedback closed-loop control. AMESim is used to build the simulation model based on the system control strategy, actuator, supercapacitor, and PMSM mathematical mode. Under typical working conditions, the simulation study is conducted on a 50-type wheel loader to obtain cylinder displacement, system energy recovery, and energy-saving performance. The simulation results show that the system is feasible and can effectively reduce energy consumption. Its energy recovery efficiency is 65.4%. The PMSM energy supply is reduced by 28.6% with the variable pressure margin control. It has high energy-saving performance, and the energy-saving efficiency is 38.5%. It provides a reference for research on energy-saving systems for electric construction machinery.

Power Train System Control of Electric Loader Based on Positive Flow System

Energy conservation and emission reduction have drawn more and more attention in the world. Loaders are widely used in various earthworks. However, traditional loaders with high energy consumption and poor emission cannot meet the needs of sustainable development. Electric loaders can achieve zero emission by replacing the engine with the electric motor, which is considered to be one of the main trends in future development. However, the existing electric loader only uses the electric motor to simulate the operation of the engine without fully considering the characteristics of the hydraulic system, resulting in the inability to optimize the energy efficiency and control performance of the system. In this paper, an electric motor with excellent speed regulation was employed. A positive flow system based on variable speed for constant displacement pump was studied. The efficiency of the power train system was analyzed. The relationships of the opening area of the main valve core, the system demand flow, and the pilot pressure were studied. A variable speed control strategy based on the pilot pressure control was put forward. In order to verify the feasibility of the proposed system and control strategy, simulation and experiments were carried out. The results showed that the proposed system has better energy saving and maneuverability than the traditional constant flow system.

Automatic Shift Control of an Electric Motor Direct Drive for an Electric Loader

Traditional loaders with engines present the drawbacks of high energy consumption and poor emissions performance. The usage of an electric motor instead of an engine in an electric loader can effectively improve energy efficiency and emissions. The loader is mainly used in the earthwork construction of unstructured roads. Compared to the automobile, during the working process of the loader, the load fluctuates violently, and the vibration is serious. A large torque range during operation, a wide speed range during transfer, and frequently switching gears to ensure power are required by the loader. Therefore, the automatic shift control strategy for an automobile cannot be well applied to the loader directly. In this paper, a novel distributed electric motor-driven loader in which the walking drive system and the hydraulic system is decoupled is studied. The shift rule of the electric loader is also studied. A comprehensive automatic shift control strategy considering power and economy is proposed. Simulations are carried out to verify the feasibility of the proposed control strategy. The results show that under the “V” cycle operation condition of the loader, the shift rule meets the control requirements and the shift effect is obvious and reasonable. In terms of transfer conditions, the proposed control strategy yields ideal power performance and energy savings.

Energy Consumption Prediction of Electric Construction Machinery Based on Condition Identification

Energy saving and emission reduction have become the consensus of global development. Electric construction machinery has drawn more and more attentions due to its zero emission and high efficiency. However, because of the installed capacity of the battery, the complex working conditions and the time-varying load of construction machinery, the working time of electric construction machinery is hard to estimate. It is important to accurately predict the remaining working time of the whole machine to ensure that the driver can reasonably arrange the operation time. In this paper, the electric loader is studied. To improve the estimation accuracy of the working time of electric loader, the typical working conditions are analyzed. The data of V-type working mode cycles of the actual experimental prototype are analyzed, which provides the basis for the segmentation of working conditions and the extraction of characteristic parameters. The fuzzy C-means clustering algorithm is used, an estimation method of operation energy consumption based on working condition identification is proposed. The results show that the energy consumption estimation method based on the motor average torque proposed in this paper has better estimation accuracy than the traditional estimation method based on the latest unit time energy consumption, which provides an idea for estimating the working time of electric loader and has certain practical significance.

Power Uninterrupted Shift Strategy of Electric Loader Based on Coordinated Control of Drive Motor and Wet Clutch

Power Uninterrupted Shift Strategy of Electric Loader Based on Coordinated Control of Drive Motor and Wet Clutch

Comprehensive testing of warehouse equipment as the most important part of the certification of a new serial product and its safe operation

Warehouse storage today is not complete without the use of lifting and loading equipment. Loaders are indispensable for unloading vans, transporting and stowing various cargoes, and modern realities require high performance, reliability and safety from this kind of equipment, including when working around the clock. Before the new loader is approved for serial production, the concept must pass a number of comprehensive safety and reliability tests. These tests are an important part of the internal and external certification of a new product, since the electric loader operates in a high-risk area — lifting several tons of cargo in areas where people work.

Operating Performance of Pure Electric Loaders with Different Types of Motors Based on Simulation Analysis

The electrification of loader designs can utilise several power motor types. Hence, this study investigates the operational performance of pure electric-powered loaders matched with three types of motors. Firstly, for the ZL08 loader, it is proposed that a pure electric-powered loader structure adopts two motors to drive the walking and hydraulic systems separately. Secondly, the dynamic parameters of the two motors were matched, and then, a joint vehicle dynamics model of the control system, the Multi-Body Dynamics (MBD) module and the material Discrete Element Method (DEM) module, was established. Finally, the performance of the walking system with three motors was tested by inserting three materials and using accelerating and climbing methods. The operating performance of the hydraulic system was tested by shovelling and unloading three materials. Results show that when inserting difficult materials, the loader’s walking system with switched reluctance motors is 9.74–21.2% deeper than that with the other two motors and 11.7–56.2% faster at the same depth. The hydraulic system consumes 3–15.7% less energy when matched with a permanent magnet synchronous motor than the other two motors. Pure electric loaders have the best operating performance when the walking system is matched with a switched reluctance motor, and the hydraulic system is matched with a permanent magnet synchronous motor.

Control strategy of genetic algorithm for a hybrid electric container loader

A genetic algorithm is applied to optimise the control parameters of a hybrid electric loader. Based on the optimal control parameters, a multidimensional response surface model for control parameters was established by a response surface method. The simulation shows that under multiple loads, battery temperatures and initial SOCs, the fuel saving of the hybrid loader is significant, the battery maintains the charge sustain or reaches within the optimal range, the battery temperature rise is kept within a reasonable range, and the battery charge and discharge rate is controlled within 1C. The fuel consumption of the hybrid electric loader is reduced by more than 20% compared with the traditional loader under the full load conditions. Compared with the original calculation model optimised by genetic algorithms and the dynamic programming, it was verified that the calculation accuracy and fuel saving significance of the response surface model for control parameters.

Calculation of the resource of spiroid transmissions from wear in the step of loading mode

The analysis of the failure causes of the mechanisms and drives of lifting, construction, road machines on the basis of gearing gears, as well as gears of the worm class, which are contact destruction of the active surfaces of gear teeth, leading to malfunctions, breakdowns, failures in the form of wear and scuffing. A cyclogram describing the mode of operation of the gear pair, taking into account the effect of maximum load on the contact endurance and on the endurance of the teeth during bending, and which is used in strength calculations of spur and helical gears, is given. The necessity of creating a method for calculating the wear of spiroid gears based on the variable loading mode and load time taking into account the loading schedule analysis of mechanisms and drives of hoisting-and-transport machines and equipment where this type of gear is used, in particular, in the drive of stop valve mechanisms, in the drive of screw horizontal conveyor, the cable-assembly mechanism of the electric loader, in the drive of the traction winch of the packing crane UK-25/9-18 for tugging packages of rail track panel, is substantiated. The developed method makes it possible, taking into account the actual operation modes of hoisting-and-transport machines, equipment and mechanisms, by experimentally obtained dependence of the wear rate of the spiroid wheel teeth on the torque values on the output shaft of the spiroid gearbox, to determine the values of wear intensity and calculate the duration of the resource of the spiroid gearbox in accordance with the established schedule of variable mechanism loading for lifting, construction and road cars.

Implementation of the interaction of the steering wheel loader control system of the remote-controlled wheeled vehicle operator interface with a real-time simulation model

A wheeled vehicle remote control workstation should include systems and devices that would provide steering feedback for the operator. The electric loader of the steering wheel with digital control can act as a system of this kind. Development and adjustment of the steering wheel loader can be performed with real-time simulation models sufficiently reflecting the behavior of the remote-controlled vehicle. The paper describes interaction of the real-time simulation model of an 8x8 wheeled chassis with the prototype of a steering wheel loader control system. The authors demonstrate compatibility of the software and hardware components in question, show adequacy of the model during interaction with the steering wheel loader control system, and propose using such models during the development of the remote control operator workstations.