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 Comparative Study on the Truck Frame Stiffness with Solid and Beam Element FEA Models

Truck frames should be designed and fabricated with enough rigidity to avoid excessive deflections. Finite element analysis (FEA) plays an important role in all stages of frame designs. While being accurate, 3D solid element FEA models are built upon frame configuration details which are not feasible in the preliminary design stage, partially because of limited available design data of frames and heavy computation costs. This research develops 1D beam element FEA models for simulating frame structures. In this paper, the CAD model of a truck frame is first created. The solid element FEA analysis, which is adopted as the baseline in this study, is subsequently conducted for the stiffness of the frame, Next, beam element FEA analysis is performed for validating the feasibility of the beam element FEA model by comparing the results from the solid and beam element FEA models. It is found that the beam element FEA model can predict the frame stiffness with acceptable accuracy and reduce the computation cost significantly.

Simulating Coupled Longitudinal, Pitch and Bounce Dynamics of Trucks with Flexible Frames

Simulating the dynamic response of trucks requires that a model be constructed and subjected to road inputs. Inclusion or omission of flexible frame effects is often based on intuition or assumption. If frame vibration is assumed to be significant, it is typically incorporated in one of two ways. Either a complex finite element model of the frame is used, or a simplified linear modal expansion model (which assumes small motions) is employed. The typical low-order modal expansion model, while computationally efficient and easier to use, is limited by the fact that 1) large rigid body motions and road grade changes are not supported, and 2) longitudinal dynamics are not coupled to vertical and bounce dynamics. In this paper, a bond graph model is presented which includes coupled pitch and bounce motions, longitudinal dynamics, and transverse frame vibration. Large rigid body motions are allowed, onto which small flexible vibrations are superimposed. Frame flexibility is incorporated using modal expansion of a free-free beam. The model allows for a complete pitch-plane representation in which motive forces can propel the truck forward over varying terrain, including hills. The effect of frame flexibility on vehicle dynamics can then be studied. This is an extension of the typical half-car model in which suspension motion is assumed vertical, pitch angles are small, and longitudinal dynamics are completely decoupled or omitted. Model output shows the effect of frame flexibility on vehicle responses such as forward velocity, pitch angle, and payload acceleration. Participation of individual modes can be seen to increase as road input approaches their natural frequency. The bond graph formalism allows for any or all flexible frame modes to be easily removed from the model if their effects are negligible, and for inclusion of more complex submodels for components such as suspension and engine if desired.

汽车起重机车架强度校核及尺寸优化

车架是汽车起重机的重要组成部分,其承载能力对起重机的工作性能有着比较大的影响。以60 t某型汽车起重机结构中车架作为研究对象,将车架的参数模型导入Hypermesh软件中对其进行有限元分析。车架模型整体使用四节点网格进行划分,并对其进行静力学计算,计算其在危险工况下所产生的von Mises应力、变形。对不符合强度、刚度要求的车架初始模型进行结构改进,使其满足要求。最后使用OptiStruct软件对车架模型进行尺寸优化,以车架部分壳单元板厚为设计变量,车架刚度、强度为约束条件,车架最小质量为目标。优化后的车架质量减少了0.599 t,减重率为6.0%。

轨道式升降采摘车的控制系统设计

针对果蔬的采摘和运输机械化程度较低的问题,对轨道式升降采摘车的控制系统进行了设计。采摘车的主要组成包括控制系统、液压系统、动力系统、升降系统、采摘系统和行走系统。在升降平台作业时,可能存在升降平台侧翻或者铰架受力过大的问题,为了保证作业安全,对升降平台的底盘和铰架进行了受力分析和尺寸结构设计。为验证该轨道式升降采摘车的性能,对其进行了行走试验和升降试验,结果表明:采摘车通过性良好,且可以满足采摘车对升降高度的精度要求。

基于平台化的重卡车架设计开发

车架不仅是整车的主要承载件之一,而且是与其他系统边界关联最多的共享模块,整车的很多零部件都直接或间接的安装在车架上。在商用车平台化设计中,车架设计的好坏,直接影响到后期产品的可拓展性及技术兼容性,影响到变形产品拓展的难易程度。在商用汽车竞争日趋激烈的情况下,如何快速响应市场,提供市场所需产品,车架设计的重要性更是不言而喻。本文结合实际项目经验,总结和探讨了平台化设计中,车架设计的主要内容,前部宽度、后部宽度、变截面长度及拐点位置,孔位布局等关键参数的设计,以及需要注意事项,旨在对平台化设计中车架的设计开发提供参考依据。

自卸车车架有限元分析与轻量化设计

自卸车车架的轻量化一直是整车厂的设计目标之一,车架轻量化不仅可以节约材料和成本,也可以减少油耗,提高经济性。文章以某型自卸车为研究对象,运用ANSYS软件对车架进行三种工况静力学分析,根据仿真分析数据对车架进行轻量化设计,选取最佳优化方案,对轻量化的车架进行静态和模态分析,验证其是否满足使用要求,分析及轻量化设计自卸车车架对增加自卸车辆的整车使用寿命,对提高其安全可靠性和经济性有一定的工程实践意义。

电动微卡高速抖动分析与控制

针对电动微卡高速抖动问题进行了分析,对高速抖动问题产生的机理及传递路径进行了阐述。同时就电动微卡高速抖动问题,从激励源到传递路径及响应点进行了排查分析,明确了产生抖动问题的原因是轮胎一阶不平衡激励引起前簧簧下系统振动,并与车架产生共振,进而引起驾驶室产生强迫振动。针对问题原因提出了控制轮胎的动平衡及端跳、径跳,减少激励源振动,以及通过提高轮胎刚度,提升簧下偏频的解决方案。从实际测试结果上看,效果明显,对实际工程问题的解决具有指导意义。

矿用自卸车车架模态分析与试验验证

矿用自卸车行驶中因受到强烈振动会出现共振或疲劳破坏的现象。通过ANSYS软件建立用于模态分析的矿用自卸车车架有限元模型,并利用模态分析获取车架固有频率及其相应振型,结合激振试验评估模型精度,分析各试验模态与计算结果出现差异原因,并提出规避共振现象的改进措施,进而提升自卸车使用寿命。同时,该结果也可为车架动态特性研究及优化设计提供理论支撑。

无副车架自卸汽车车架多目标轻量化优化

为了进行无副车架自卸汽车车架轻量化设计,本文应用有限元分析软件,建立无副车架自卸汽车车架有限元模型。对扭转工况下车架结构强度进行有限元分析,得到车架应力分布,并对车架进行模态分析,根据车架结构强度的有限元计算结果,对安全系数较高的结构件进行灵敏度分析,确定优化设计变量。采用最优拉丁超立方法进行样本采集,建立Kriging近似模型,以质量和最大应力最小作为目标,以一阶模态频率为约束,基于NSGA-II算法对自卸汽车车架进行多目标优化设计。优化结果表明,在保证车架模态频率的情况下,质量减小了15.55%,最大应力减少了1.55%。该优化方法满足设计要求,具有较好的轻量化效果。

基于ANSYS的轻卡车架模态分析及结构优化

为了研究轻型卡车车架结构的动态特性,对其车架结构进行有限元模态分析及优化设计。首先,运用SolidWorks 2020软件建立轻卡车架三维实体模型,进而利用ANSYS Workbench 2021软件进行模态分析,得到前6阶固有频率,并与车架激励频率进行对比研究,从而对轻卡车架进行结构优化,将优化结构的固有频率再与激励频率进行对比分析。

重型自卸车副车架强度分析及轻量化设计

为了提高某重型自卸车副车架的可靠性,采用UG软件对自卸车卸货过程进行运动仿真,获得自卸车举升装置的加载曲线和副车架受最大载荷时推力油缸的位置;利用Hyper Mesh软件建立副车架的有限元分析模型,计算初始举升、货物下滑临界工况下副车架的应力分布和变形量。基于有限元仿真结果,以初始举升工况为设计工况对副车架进行尺寸优化,支撑梁的最大应力从477.2 MPa降至313.6 MPa。研究结果显示:通过对副车架进行尺寸优化,实现了满足强度前提下副车架轻量化的设计要求,为产品的后续设计提供了依据。

基于有限元的无副车架重型自卸汽车车架结构改进设计

为解决重型自卸汽车自重大、质心高的问题,研发了一种无副车架的重型自卸汽车车架结构。采用有限元技术建立车架有限元模型,在各极限工况下对车架结构强度进行有限元分析,得到车架的应力分布,并对车架结构强度不足之处进行改进设计,改进设计后的无副车架重型自卸汽车车架结构,可满足自卸汽车行驶作业的安全性和可靠性需求。

重卡车架制造工艺发展趋势解析

车架总成是构成重型卡车的核心零部件之一,承载着整车各类功能总成,被誉为重卡的脊梁。随着国民经济的快速发展,客户对重卡产品有了低油耗、多配置、大马力、长生命周期的新需求,而现有重卡车架总成制造工艺不能完全满足这些新需求。文章从客户需求解读、工艺现状剖析、先进制造技术可行性分析等方面展开探讨,得出了轻量化材料成型、柔性快速制孔、纵梁局部变形、散件电泳等符合重卡行业发展的工艺技术路线,也形成了当前车架总成制造工艺的发展趋势。

某矿用自卸车推力杆支架结构设计与特性研究

矿用自卸车运行工况恶劣,因超载、疲劳使用、载荷不均等因素导致车架横梁损坏严重,极大地影响车辆的可靠性。针对此问题,文章以某90 t矿用自卸车为参考模型,以直推力杆支架为研究对象,分析车架横梁承载情况,优化设计一种新型推力杆支架结构,并进行有限元分析。结果表明,优化后的新型推力杆支架可以降低车架横梁静强度下最大应力,提高整车的可靠性和疲劳寿命,进而提升整车安全性。

某型载货车车架结构轻量化设计

建立了某型载货车车架结构的应力分析有限元模型 ,计算了多种工况下车架结构的应力分布并以已有的试验结果进行验证。在此基础上 ,提出该车架结构的轻量化设计方案 ,并进行了改进设计后车架结构的强度分析 。

自卸汽车车架模态试验与分析

针对某自卸汽车在使用过程中出现的横向抖动问题,采用试验模态分析技术对车架动态性能进行了分析,得到了该车架的各阶模态频率、模态阻尼以及模态振型等。分析结果表明,该自卸汽车车架前部刚度较弱,当激励频率接近或等于5.75Hz和10.36Hz时,可使车架共振产生横向抖动。从而为进一步研究整车振动、疲劳、噪声等问题奠定了基础,也为车架结构的优化设计提供了参考依据。

集装箱半挂车车架结构拓扑优化设计

用 ANSYS软件对某集装箱半挂车车架进行了结构拓扑优化设计。探讨了拓扑优化设计过程中 ,基本结构建立、优化过程控制及优化结果分析与应用等问题 ,分析了 ANSYS软件中有关拓扑优化函数的应用方法。实现了拓扑优化方法在汽车结构的初始设计过程中的应用。

轻型载货汽车车架动态特性分析与研究

为了改进某轻型载货汽车车架的结构,对边梁式车架进行了一定的简化。考虑到悬架对车架动态特性的影响,建立了车架及悬架系统的几何模型和有限元模型。利用大型有限元软件ANSYS对建立的模型进行了有限元模态分析,获得了车架的模态参数。通过模态分析法对车架模型进行了验证,确定了该车架结构的安全性和可靠性,为后续的动力学分析及实验提供了参考,对车架的设计和结构改进具有一定的指导意义。