A comparative study on kinetics and dynamics of two dump truck lifting mechanisms using MATLAB simscape

In this paper,two lifting mechanism models with opposing placements,which use the same hydraulic hoist model and have the same angle of 50°,have been developed.The mechanical and hydraulic simulation models are established using MATLAB Simscape to analyze their kinetics and dynamics in the lifting and holding stages.The simulation findings are compared to the analytical calculation results in the steady state,and both methods show good agreement.In the early lifting stage,Model 1 produces greater force and discharges goods in the container faster than Model 2.Meanwhile,Model 2 reaches a higher force and ejects goods from the container cleaner than its counterpart at the end lifting stage.The established simulation models can consider the effects of dynamic loads due to inertial moments and forces generated during the system operation.It is crucial in studying,designing,and optimizing the structure of hydraulic-mechanical systems.

Real-Time Co-optimization of Gear Shifting and Engine Torque for Predictive Cruise Control of Heavy-Duty Trucks

Fuel consumption is one of the main concerns for heavy-duty trucks.Predictive cruise control(PCC)provides an intriguing opportunity to reduce fuel consumption by using the upcoming road information.In this study,a real-time implementable PCC,which simultaneously optimizes engine torque and gear shifting,is proposed for heavy-duty trucks.To minimize fuel consumption,the problem of the PCC is formulated as a nonlinear model predictive control(MPC),in which the upcoming road elevation information is used.Finding the solution of the nonlinear MPC is time consuming;thus,a real-time implementable solver is developed based on Pontryagin’s maximum principle and indirect shooting method.Dynamic programming(DP)algorithm,as a global optimization algorithm,is used as a performance benchmark for the proposed solver.Simulation,hardware-in-the-loop and real-truck experiments are conducted to verify the performance of the proposed controller.The results demonstrate that the MPC-based solution performs nearly as well as the DP-based solution,with less than 1%deviation for testing roads.Moreover,the proposed co-optimization controller is implementable in a real-truck,and the proposed MPC-based PCC algorithm achieves a fuel-saving rate of 7.9%without compromising the truck’s travel time.

A human-sensitive frequency band vibration isolator for heavy-duty truck seats

In this study,a human-sensitive frequency band vibration isolator(HFBVI)with quasi-zero stiffness(QZS)characteristics for heavy-duty truck seats is designed to improve the comfort of heavy-duty truck drivers on uneven roads.First,the analytical expressions for the force and displacement of the HFBVI are derived with the Lagrange equation and d'Alembert's principle,and are validated through the prototype restoring force testing.Second,the harmonic balance method(HBM)is used to obtain the dynamic responses under harmonic excitation,and further the influence of pre-stretching on the dynamic characteristics and transmissibility is discussed.Finally,the experimental prototype of the HFBVI is fabricated,and vibration experiments are conducted under harmonic excitation to verify the vibration isolation performance(VIP)of the proposed vibration isolator.The experimental results indicate that the HFBVI can effectively suppress the frequency band(4-8 Hz)to which the human body is sensitive to vertical vibration.In addition,under real random road spectrum excitation,the HFBVI can achieve low-frequency vibration isolation close to 2 Hz,providing new prospects for ensuring the health of heavy-duty truck drivers.

A Predictive Energy Management Strategies for Mining Dump Trucks

The plug-in hybrid vehicles(PHEV)technology can effectively address the issues of poor dynamics and higher energy consumption commonly found in traditional mining dump trucks.Meanwhile,plug-in hybrid electric trucks can achieve excellent fuel economy through efficient energy management strategies(EMS).Therefore,a series hybrid system is constructed based on a 100-ton mining dump truck in this paper.And inspired by the dynamic programming(DP)algorithm,a predictive equivalent consumption minimization strategy(P-ECMS)based on the DP optimization result is proposed.Based on the optimal control manifold and the SOC reference trajectory obtained by the DP algorithm,the P-ECMS strategy performs real-time stage parameter optimization to obtain the optimal equivalent factor(EF).Finally,applying the equivalent consumption minimization strategy(ECMS)realizes real-time control.The simulation results show that the equivalent fuel consumption of the P-ECMS strategy under the experimentally collected mining cycle conditions is 150.8 L/100 km,which is 10.9%less than that of the common CDCS strategy(169.3 L/100 km),and achieves 99.47%of the fuel saving effect of the DP strategy(150 L/100 km).

Cycle Time Analysis of Open Pit Mining Dump Trucks

This study demonstrates a practical cycle time analysis of dump truck haulage system of “Ukhaa Khudag” open-pit coal mine located in Umnugobi Province, Mongolia. It examines the possibility of minimizing the cycle time of the haulage system as well as factors impacting the speed of the dump truck. The current study divides the open pit mine road for the dump trucks into five sections which are bench road, ramp, surface road, dump road uphill, and dump road. Meanwhile, it investigates the influence of the length, the grade, and the rolling resistance of the road section on the cycle time. The data is analyzed using mathematical regression methods via Microsoft Excel program. For each of the five road sections, we compare the statistical calculations of three regression models: linear, quadratic and exponential;thus, a total of thirty regression models are obtained in this research. Accordingly, the cycle time for each road section is predicted by the most accountable model. The loaded and empty direction of the movement is measured and calculated for each road section, and it appears that the difference between the calculated mean value and the actual cycle time of the models is 0.82 seconds with a relative error of 2.51 percent.

State Estimation of the Electric Drive Articulated Dump Truck Based on UKF

The requirements of vehicle dynamic stability control are higher than ever as the significant increase of electric drive articulated vehicle speed. According to the construction features of articulated dumping truck and nonlinear characteristics of moving vehicles,nonlinear observer of vehicle status is designed to strength robustness of dynamic control system in this paper. A 4-degree-of-freedom nonlinear dynamic model of articulated electric drive vehicle is built as reference model to estimate the state of the articulated vehicle. And by adopting Unscented Kalman Filter( UKF) algorithm,a series of state parameters such as longitudinal velocities of front and rear frames,yaw rate and side-slip angle are estimated. During the test of 60 t articulated electric drive vehicle,2 inertial navigation modules are installed in the front frame and rear frame respectively and the speed of each electric drive wheel is obtained simultaneously. As the test results suggest,in various working conditions,the algorithm based on UKF is able to accurately estimate the state parameters of articulated vehicle with the estimated error less than 5%. The proposed method is justified to be the theoretical basis and application guidance for articulated vehicle stability control.

Operator health risk evaluation of off-highway dump truck under shovel loading condition

To evaluate the operator health risk exposed to whole-body vibration(WBV) while the electric-shovel loads the ore on the truck body, the semi-truck mathematical model and 3-D virtual prototype were built to simulate the high shockwave of truck cab under the shovel loading. Discrete element method was utilized to accurately estimate the impacting force on the truck body. Based on the ISO 2631-5 criteria, the Sed is about 0.56 MPa in both models, which means that the dump operators have a high probability of adverse health effects over long-term exposure to these vibrations. The 4-DOF operator model was built to investigate the biodynamic response of seated-human body exposed to WBV in terms of the transmission of vibrations through the body. The results show that the response peak is in the frequency range of 4-6 Hz corresponding to the primary body resonant frequency.

大型矿用自卸车厢斗装载程序分析及力学特性研究

自主装卸是智能矿山建设中亟待突破的关键技术,电铲-矿用自卸车合理的装载程序能够显著降低电铲装卸作业难度,降低复杂动态载荷对厢斗力学性能的影响。以某型号矿用自卸车厢斗为研究对象,依据厢斗容量标定方法建立了厢斗的堆装模型,确定厢斗堆装容积;分析了厢斗安装特点及结构特征,结合现场实际装载经验,提出了三种不同的装载程序,并利用离散元方法对三种装载程序进行仿真分析,研究不同装载程序下厢斗装载量、物料均匀性及底板承受的压力等;在此基础上,通过仿真分析研究厢斗满载工况下的力学特性。结果表明,在厢斗装载过程中将装载位置放在厢斗满载重心及前侧位置可提升装载量,各铲装载位置尽量靠近厢斗横向方向的中轴线,本文提出的装载程序二的装载量最大,物料可通过自身堆积特性装满厢斗,并在厢斗内部的均匀性更好,且物料装满后厢斗底板的总压力最小,当满载后厢斗的最大变形量为7.50 mm,最大应力为326.85 MPa,满足刚度、强度设计要求。

矿用重载轮胎趾口空问题的研究

通过市场返回轮胎断面剖析,结合有限元仿真分析造成矿用重载轮胎趾口空的原因,并提出相应的解决措施。通过采取适当减小胎圈内直径,适当增大胎圈与轮辋过盈量、三角胶尺寸、胎体反包高度,提高耐磨胶的硬度和耐老化性能,在推荐充气压力和负荷范围内使用轮胎及在车辆上安装液压减速器以降低刹车片使用频次等措施,可降低趾口空发生率,延长轮胎使用寿命。

矿用重载轮胎接地印痕的研究

以14.00R25宽体自卸车轮胎为例,通过轮胎使用情况调研,结合实验室测试和轮胎有限元仿真,研究矿用重载轮胎接地印痕及接地压力分布。结果表明:宽体自卸车轮胎接地印痕形状应接近矩形且接地压力分布均匀;影响轮胎接地印痕及接地压力分布的主要因素为断面高宽比、胎冠弧半径和弧度高、带束层角度和宽度、花纹沟壁角度和花纹沟宽度等。通过有限元仿真优化设计可避免轮胎出现花纹掉块和非均匀磨损等问题,提高设计效率。

电动矿用车前悬架K&C特性研究及性能优化

针对电动矿用车的双叉臂前悬架结构在实际运行中出现的严重轮胎磨损及前车架裂纹等问题,采取逆向思维对悬架关键定位参数进行仿真及关键硬点分析,以此优化双叉臂前悬架的操纵稳定性。首先通过SolidWorks软件根据图样尺寸创建双叉臂前悬架仿真模型,并导入ADAMS中,以此获取精确硬点坐标,调用ADAMS/Car进行前悬架K&C特性仿真分析。仿真结果表明,悬架前束角和轮胎侧向位移的相对异常变化量最明显,且超出了最优设计范围。最后运用ADAMS/Insight求解器对悬架的异常定位参数进行权重比设置及多目标优化。最终结果表明,优化后轮胎侧滑位移的优化率约为37.95%,前束角变化量的优化率约为34.77%。证明轮胎磨损情况得到有效改善,前悬架的整体操纵稳定性及结构稳定性有所提升。

某型电动轮自卸车车厢强度分析与尺寸优化设计

以某型220 t电动轮自卸车车厢为研究对象,利用HyperWorks建立了自卸车车厢的有限元模型,对自卸车车厢的满载静止、满载转弯、满载制动、满载转弯制动、满载匀速及满载举升6种工况进行有限元分析,并基于Optimization模块对车厢厢体结构进行了尺寸优化,以该自卸车车厢板块厚度作为设计变量,在保证结构应力满足设计要求的前提下尽量减少车厢的质量,最终车厢整体质量降幅达到22.9%,实现了车厢轻量化设计目标。

基于集成学习的某重型自卸车车厢多目标优化

针对复杂自卸车车厢结构的轻量化设计问题,提出一种集成学习联合多目标优化的设计方法。以某重型自卸车车厢为研究对象,建立了高保真的车厢有限元模型,并进行3个典型静力学工况和自由模态的结构性能仿真分析。通过贡献度分析筛选出重要零部件的厚度为设计变量,以危险工况下的最大位移、最大等效应力及自由模态第1阶固有频率为约束条件,以质量和满载举升0°工况下的最大位移为优化目标,运用极端梯度提升(XGBoost)集成学习近似模型进行自卸车车厢多目标优化设计。经优化决策后的轻量化设计表明:在满足基本静动态结构性能要求下,车厢满载举升0°工况下的最大位移减少了1.98 mm,减少幅度为8.57%,车厢质量减少了0.207 t,减少幅度为6.64%,取得了较好的轻量化效果。

铰接式自卸车分动箱的强度与刚度分析

铰接式自卸车使用环境恶劣,其分动箱必须具备较高的可靠性与安全性。以铰接式自卸车分动箱为研究对象,在SolidWorks软件中建立分动箱三维装配模型,通过MSC.Patran软件建立有限元模型,基于Masta软件以实际工况为基础建立载荷谱;对分动箱箱体、传动轴、传动齿轮等重要零部件的综合位移、综合刚度、齿轮接触应力等强度和刚度特性进行分析,同时计算了轴承在该载荷谱下的使用寿命。研究为分动箱结构优化、性能优化、使用寿命提升等提供了参考和技术支持。

物料动态安息角对矿用自卸车厢斗结构影响规律

针对矿用自卸车行驶过程中的厢斗内物料稳定性问题,研究厢斗内物料动态安息角对厢斗结构设计的影响。首先,基于离散元方法,分析煤颗粒在自然状态下的安息角;进一步,建立厢斗简化模型,研究不同安装角度下矿车正常行驶及爬坡过程中物料的动态安息角,并分析物料滑动规律;结果表明:在水平路面行驶工况下物料动态安息角随厢斗安装角度增加而减小,而爬坡过程中由于厢斗内物料的滑动导致动态安息角随安装角度的增加先缓慢减小再变大再快速减小;当安装角度为10°时可有效避免厢斗内物料的滑动;最后,以确保厢斗稳定性装载及不撒料为目标,提出厢斗侧板后端的角度设计公式,为厢斗结构设计提供理论依据。

露天矿无人驾驶自卸车横-纵向协同控制研究

露天矿无人驾驶自卸车面临道路等级低且坡道弯道多、车辆载质量大且变化范围宽等恶劣运输工况,现有车辆运动控制策略多面向普通道路环境,无法直接将现有车辆控制策略应用于矿山自卸车。针对上述问题,提出了一种基于预瞄误差与分层反馈的露天矿无人驾驶自卸车横-纵向协同控制系统。横向控制以线性二次型调节器(LQR)为基础,运用前馈控制器降低稳态误差,采用模糊控制器实现自适应调整预瞄距离,以提高路径跟踪控制精度;纵向控制建立分层反馈式纵向速度控制器,分别采用模型预测控制和模糊PID反馈控制,并建立车辆驱动及制动逆向模型,降低自卸车载质量与道路坡度改变对纵向速度追踪的影响。仿真结果表明:(1)车辆实际速度和期望速度误差在2%以内,说明自卸车在空载下坡与满载上坡2种工况下的速度跟踪效果能够满足要求。(2)由于横-纵向协同控制能够针对路径曲率的不同实时调节车辆速度,在2种工况下,自卸车横-纵向协同控制器相比于单一横向控制都获得了更高的路径跟踪精度,同时也提高了自卸车的操纵稳定性。实验结果表明:(1)空载下坡时的横向误差峰值为0.0199 m,方向误差峰值为0.1840 rad,误差增大均发生在弯道处,但误差波动范围较小,能够保证试验车对期望路径的跟踪。(2)负载上坡时的横向误差峰值为0.0168 m,方向误差峰值为0.0714 rad,误差变化趋势与空载下坡试验相反,但误差仍在合理范围内,试验车的跟踪效果良好。(3)2个误差峰值均小于空载下坡试验,验证了不同速度对横向控制精度的影响规律。

154T电动轮自卸车传动系统仿真研究

针对154T电动轮自卸车传动系统研发周期长、成本高、风险大等问题,提出基于Matlab/Simulink软件构建154T电动轮自卸车电传动恒功控制仿真系统,以矿用自卸车的实际运行工况作为仿真参数输入,对电动轮自卸车的柴电系统与电传动系统整机进行联合仿真。仿真结果表明,本研究所构建的系统能够获得整机状态运行数据,为电动轮自卸车电传动系统控制算法改进、电机参数优化提供依据,缩短研发周期,降低研发成本及风险。

应用TruckSim自卸车操纵稳定性在环仿真平台研究

自卸车良好的操纵稳定性既保证整车正常运行,也保证矿山正常生产运营。根据自卸车整车结构特点和设计参数,基于TruckSim搭建所研究自卸车整车动力学模型,包括电传动系统、悬架系统、转向系统和轮胎等。将悬架系统K&C特性作为整车模型唯一可变输入。基于动力学模型进行操纵稳定性开环仿真,包括方向盘角阶跃、角脉冲和稳态回转仿真。基于TruckSim整车模型,结合PXI实时硬件和Labview搭建整车操纵稳定性驾驶员在环仿真平台,对整车进行双移线工况下闭环试验,对整车操纵稳定性进行分析。分析结果表明:总体上能够很好响应驾驶员操纵并沿着目标路径行驶,且转向轻便;但行驶路径与期望路径存在一定差异,驾驶员需要多次调整转向盘转角才能完成双移线;研究内容和研究结论为进一步实车测试提供参考依据。

电驱自卸车在露天煤矿中的应用前景分析

为了贯彻实行国家环保相关政策,结合露天矿目前生产实际,调研行业内主流运输自卸车的使用情况,分析了燃油自卸车和电驱自卸车经济、使用效能等方面的优缺点;通过不同角度对比得出电驱自卸车相比燃油自卸车优势显著,同时结合当下环境和政策,新能源自卸车快速发展,电驱自卸车将成为市场主流选择。

自卸车右转盲区风险目标动态检测算法研究

针对自卸车外形尺寸大导致车辆右转弯时存在较大视野盲区的问题,提出一种自卸车右转盲区风险目标动态检测算法,该算法利用YOLOv8模型的C2f模块和损失计算模块,提高了模型的检测精确率。同时,在盲区中预设4条位置阈值线,增加盲区风险预警模块,建立了自卸车右转盲区辅助驾驶系统。结果表明:所提出的风险目标动态检测算法能够识别小型乘用车、载货汽车、公交车、行人和电动自行车等多种类型的目标,且所有类别目标的50%交并比阈值下的平均精度均值(mAP50)为0.87;自卸车右转盲区辅助驾驶系统能够根据图像中风险目标框的位置进行不同程度的预警。