Parameters Matching and Control Method of Hydraulic Hybrid Vehicles with Secondary Regulation Technology

Hydraulic hybrid vehicles （HHV） with secondary regulation technology has the potential of improving fuel economy by operating the engine in the optimum efficiency range and making use of regenerative braking. Hydrostatic transmission technology has the advantage of higher power density and the ability to accept the high rates and high frequencies of charging and discharging, both of which are not favorable for batteries, but the lower energy density requires special power matching design and control strategy to coordinate all the powertrain components in an optimal manner. A multi-objective optimization method is proposed to distinguish the components size values of HHV by considering the requirements of driving cycles and technology aspects. The regenerative braking strategy and energy control strategy based on the optimized HHV is proposed to recovery the braking energy and distribute the regenerated braking energy. Simulation results show that by taking the optimized configuration of HHV, adopting the regenerative braking strategy and energy control strategy are helpful to improve the system efficiency and fuel economy of HHV under urban driving cycles.

Dynamic simulation and optimal control strategy for a parallel hybrid hydraulic excavator

The primary focus of this study is to investigate the control strategies of a hybrid system used in hydraulic excavators. First, the structure and evaluation target of hybrid hydraulic excavators are analyzed. Then the dynamic system model including batteries, motor and engine is built as the simulation environment to obtain control results. A so-called multi-work-point dynamic control strategy, which has both closed-loop speed PI (proportion integral) control and direct torque control, is proposed and studied in the simulation model. Simulation results indicate that the hybrid system with this strategy can meet the power demand and achieve better system stability and higher fuel efficiency.

CONSTANT WORK-POINT CONTROL FOR PARALLEL HYBRID SYSTEM WITH CAPACITOR ACCUMULATOR IN HYDRAULIC EXCAVATOR

Limitations of various accumulators in hybrid hydraulic excavator are analyzed. A program using capacitor as the accumulator based on constant work-point control is put forward. A simulating experimental system of hybrid construction machinery is established, and experimental study on constant work-point control for parallel hybrid system with capacitor accumulator is carried out using the pressure and flow rate derived from boom cylinder of hydraulic excavator in actual work as the simulating loads. A program of double work-point control is proposed and proved by further experiments.

Operation control strategy of series-parallel hydraulic hybrid vehicle

A series-parallel hydraulic hybrid system applied to public buses is put torwaro, ano parameters of key components are analyzed and determined. Energy management strategy based on logic thresh- old is designed which is aimed at efficient operation of the overall system considering the operational characteristic of the components and taking the curves of engine, hydraulic pump/motor and hydrau- lic pump as the main design basis; regenerative control strategy which makes regenerative brake sys- tem and frictional brake system work harmoniously is designed to raise recovery rate of regenerative brake energy. System dynamic modeling and simulation results show that the energy control strategy designed here is able to adapt system to changes of working condition and switch the operating mode reasonably. The regenerative braking control strategy is effective in raising the utilization of energy and improving fuel economy.

Input Split Hydraulic Hybrid Bus and Control Strategy

Simple and efficient energy management strategy is the key to ensure hybrid vehicle performance. Based on hybrid dynamical system theory and the concept of finite state mechanism,power split hybrid connected structure hydraulic hybrid system was proposed and described. In order to meet the demand for driving,the layered advanced control strategy was proposed in this paper,which referred to vehicle driving experience. Using Matlab /Simulink /Stateflow hybrid modeling method, the economy performance and the acceleration performance of the vehicle under the typical city driving cycles were carried on the simulation analysis. The results show that the proposed topology and control strategy can obviously improve engine output characteristic,effectively enhance the vehicle's instantaneous power performance and economy,and also has a better adaptability in different traffic environments.

DYNAMIC CHARACTERISTICS OF ELECTRO-HYDRAULIC PROPORTIONAL PRESSURE-FLOW HYBRID VALVE

The structure principles under the flow and pressure working conditions are studied, in order to investigate the dynamic characteristics of the electro-hydraulic proportional pressure-flow hybrid valve. According to the structure principles under the two different working conditions, the transfer functions under such conditions are derived. With the transfer functions, some structure elements that may affect its performance, are investigated, afterwards some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The conclusions can be used to instruct engineering applications and products designing. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works.

Instantaneous rotation speed measurement and error analysis for variable speed hydraulic system

In order to monitor the working state of piston motor and measure its instantaneous rotation speed accurately, the measuring principle and method of instantaneous rotation speed based on industrial personal computer and data acquisition card are introduced, and the major error source, influence mechanism and processing method of data quantization error are dis- cussed. By means of hybrid programming approach of LabVIEW and MATLAB, the instantaneous rotation speed measurement system for the piston motor in variable speed hydraulic system is designed. The simulation and experimental results show that the designed instantaneous speed measurement system is feasible. Furthermore, the sampling frequency has an important influ- ence on the instantaneous rotation speed measurement of piston motor and higher sampling frequency can lower quantization er- ror and improve measurement accuracy.

Mode Switching and Consistency Control for Electric-Hydraulic Hybrid Steering System

Electric-hydraulic hybrid power steering(E-HHPS)system,a novel device with multiple modes for commercial electric vehicles,is designed to realize both superior steering feel and high energy efficiency.However,inconsistent steering perfor-mance occurs in the mode-switching process due to different dynamic characteristics of electric and hydraulic components,which even threatens driving safety.In this paper,mode-switching strategy and dynamic compensation control method are proposed for the E-HHPS system to eliminate the inconsistency of steering feel,which comprehensively considers ideal assistance characteristics and energy consumption of the system.Then,the influence of disturbances on system stability is analyzed,and H_(∞)robust controller is employed to guarantee system robustness and stability.The experimental results dem-onstrate that the proposed strategy can provide a steering system with natural steering feel without apparent inconsistency and effectively minimize energy consumption.

挖掘机液压混合动力系统跟踪控制研究

由于挖掘机混合动力系统参数的不确定性和系统的非线性给挖掘机的跟踪控制带来了巨大的困难。对此,构建了挖掘机液压混合动力系统模型,并采用改进的自适应鲁棒控制(ARC)实现挖掘机液压混合动力系统的跟踪控制。根据挖掘机液压混合动力系统,对液压系统、挖掘机动力学和发动机进行数学建模。利用线性稳定反馈控制规律,采用改进的自适应鲁棒控制,使挖掘机液压混合动力系统具有足够大的反馈增益。最后对斗杆、动臂和铲斗的倾角进行跟踪仿真实验,给出了系统模型位置和速度的跟踪误差,并与PI控制进行比较分析。结果表明:相比于PI控制,ARC控制下的斗杆、动臂和铲斗倾角的最大振幅波动率和倾角的波动范围都有所降低,且回转位置和速度的跟踪误差超调较小。说明采用ARC控制的挖掘机混合动力系统控制方法,能够更好的补偿系统模型的非线性,具有较好的控制稳定性以及跟踪精度。

电液混合动力系统关键技术及能量管理研究综述

现有混合动力驱动技术以油电、油液混合动力为主,旨在提高传统燃油车辆的能量利用率、降低油耗和排放.基于液压技术的大功率密度及能量再生优势,电液混合动力系统可在全速工况范围内实现能量高效利用,提高纯电驱系统的功率密度,有效改善电动车辆续驶里程及蓄电池循环使用寿命.本文对电液混合动力系统构型、能量回收技术、能量释放模式及控制策略等相关研究成果的进展、现状及发展趋势进行综述,分析了利用电液混合动力构型与先进能量管理策略提升纯电动车辆动力性能与能量利用率的可行性技术方案与应用前景.根据已有研究成果,装备电液混合动力系统后车辆最大可降低约40%的能量消耗,在能量高效利用方面具有显著优势.对于电液混合动力系统而言,液压能再生、耦合与释放等与行驶场景及电机工况点密切相关,研究重点应解决动力耦合、再生制动与能量管理等关键技术,从而提升动力系统的综合性能特别是功率密度与节能特性.

面向混合动力汽车液压再生能量控制策略研究

针对混合动力汽车制动能量回收控制,提出了一种基于模糊Q学习的液压再生制动系统能量回收效率优化算法。建立了基于并联液压混合动力系统的汽车动力学模型,通过模糊Q学习法对汽车再生制动控制策略进行了优化。在此基础上建立了试验平台,验证液压再生制动仿真模型的准确性。与基于专家经验的模糊控制策略、动态规划算法相比,结果表明,经模糊Q学习算法优化的汽车节能率分别提高了9.62%和8.91%。

超高钢混风电塔筒液压导向系统研究

为了更加高效的利用高空风能,作为绿色清洁能源之一的风力发电,朝着风电机组单机容量越来越大、承载基础的塔筒建设高度越来越高的趋势发展。传统锥筒式全钢塔筒逐渐被预应力混凝土-钢组合塔筒所取代。预应力混凝土-钢组合塔筒兼具混凝土塔筒及钢塔筒两者的优势,具有承载力高、稳定性好、运输施工维护方便、建设成本低等特点,以适应较高高度风电场的需求,代表了未来风电塔筒结构发展的方向。由于高空风载荷大、风电机组的偏心载荷大等不利因素,导致提升过程中产生大弯矩和扭转的工况。因此,导向问题已成为预应力混凝土-钢组合塔筒建设中需要首先解决的技术难题。针对这一难题,创新研制了超高钢混风电塔筒导向液压系统,结合传感检测和智能控制算法,克服上述不利因素,依次将混凝土内塔筒和中塔筒提升到位,高质量地实现了国内陆上最高的国家电投鲁阳170 m高的风电钢混塔筒的安装。

能量再生型电液混合驱动系统参数特性研究

重型装备回转运动负载惯量大、周期性频繁启停、能耗巨大,制动能一般都以热能形式耗散,能量再生利用一直没有很好的解决方案。提出了一种新型能量再生型电液混合驱动系统并定义了系统3种工作模式,以重型装备中可逆轧机为例,研究了所提系统的特性。以电动机能耗及输出峰值功率作为评价指标,研究关键元件参数对系统驱动特性的影响规律,通过AMESim建立了纯电动驱动与电液混合驱动仿真模型。结果表明:液压泵/马达排量对制动时间、电动机峰值功率及电动机能耗影响最大;最优参数下,所提电液混合驱动系统较原电动机驱动可降低电动机峰值功率45.75%,能耗可降低48.33%,启动时间缩短44.54%,制动时间缩短1.21%。

气液混合作动装置内弹道设计与试验研究

为提升某大型起竖-翻转设备的快速响应能力,开发了一种新型燃气-液压混合作动装置,针对该新型混合动力装置,建立了变构型燃烧“凹型”药柱燃面推移变化数学模型及气液混合作动装置内弹道数值计算模型,完成了样机研制和空放试验研究,通过变构型燃烧“凹型”药柱的燃面匹配设计,实现了对不同燃烧阶段作动装置的快速建压和流量的稳定输出控制,验证了本文所建立的内弹道数值计算模型的准确性及该混合作动装置系统设计的可靠性。在此基础上,分析了“凹型”药柱设计参数对作动装置工作性能的影响,计算结果表明:作动装置输出流量的大小和响应时间的快慢主要与“凹型”药柱初始燃面及增面燃烧阶段肉厚的大小相关,药柱整体高度则决定了作动装置系统工作时间;在本文计算工况下,凹槽直径和药柱高度每增加10 mm,作动装置响应速度、平均输出流量和工作时间分别提升0.09 s、13 L/min和0.2 s左右。研究结果可为大型起竖装置的快速展开提供一种新的动力源及内弹道设计方法。

电液直驱主被动混合踝关节假肢设计与分析

穿戴踝关节假肢是膝下截肢患者恢复行走能力的重要手段。下肢假肢按照能否主动输出转矩分为被动假肢和动力假肢,其中动力假肢分为主动假肢和主被动混合假肢。被动踝关节假肢不能提供主动扭矩,应用场景有限;动力踝关节假肢能够输出主动扭矩,但存在低被动摩擦与高主动传动比不兼容问题。为了提高踝关节假肢的性能和适应性,从实际应用角度出发,基于电液直驱原理,提出了一种主被动混合踝关节假肢的新构型。首先,基于对人体踝关节角度及扭矩的分析,设计了踝关节假肢驱动系统,并提出了主被动混合踝关节假肢的总体设计方案;然后,建立了假肢系统的数学模型,通过对假肢液压系统的仿真分析验证了的假肢系统的合理性,并研制了假肢原理样机;最后,通过台架测试和人体穿戴假肢行走实验对假肢的性能进行了验证。实验结果显示:适配者行走步速为1.0 m/s(接近成年人的平均行走速度)时,假肢踝关节主动输出最大扭矩为28 N·m。研究结果表明:提出的主被动混合踝关节假肢可以实现人体行走过程中的主动助力功能,并能较好拟合人体踝关节运动姿态,增强了穿戴适应性,同时使假肢的体积和质量得到了进步的减小,为动力型下肢假肢的研究提供了设计思路和参考依据。

液电串联驱动挖掘机回转系统能耗特性研究

针对液电混驱回转装置制动能量高效回收与利用问题,提出基于电机转速控制模式与转矩控制模式的控制方式。首先,对液电混驱回转系统进行理论与原理分析;之后,在AMESim中对该系统进行了仿真分析,并为后续实验提供参考;最后,通过实验对比分析了转矩模式与转速模式差别。结果表明:转矩模式相对于转速模式运行过程更平稳,功率无波动;转速模式更有效利用蓄能器能量,相对于传统挖掘机节省48.4%,比转矩模式节省42%;转矩模式超调量比转速模式大8%,整体上转速模式优于转矩模式。

P2混联式混合动力汽车的液压控制系统设计

针对混联式混合动力汽车能量利用效率低,动力传递损耗大的问题,对混联式混合动力汽车的液压控制系统进行了研究;进行了离合器动力学、安全阀状态及液压控制系统中的流体力学分析;采用工况分析与参数化设计理念,对P2混联式混合动力汽车的液压控制系统进行了设计研究,该设计的独特之处在于改变了汽车不同工作模式的切换方式;经过实验测试,液压控制系统压力设置为3 MPa,润滑阀通径为14 mm,平衡弹簧刚度为4.5 N/mm,节流孔直径为1.2 mm时,完全开启后安全阀压力可稳定在16 bar,且该控制系统利用离合器即可完成工作模式的切换,有效提高了汽车的能量利用效率,并降低了动力传递过程中的损耗;研究设计的液压控制系统实现了新能源汽车驾驶体验的提升及汽车的节能减排。

电动VVT特点以及在混动专用发动机的应用分析

本文介绍了汽油发动机的VVT技术,对比分析了液压VVT、电动VVT的结构特点和工作原理。本文也分析了混动专用发动机的技术路径,以及对相位器的技术需求。电动VVT的调节范围大、调节速度高、温度适用广等特点,可以很好的满足混动专用发动机的需求。

综掘机截割部混合动力系统的设计与仿真分析

为解决综掘机传动动力传动系统在遇到煤岩条件突变工况时对系统零部件冲击较大且能量利用率低的问题,提出了混合动力传动系统的总体方案,并根据实际工况具体设计了液压系统中蓄能器和液压马达的选型,机械系统中扭矩耦合齿轮的参数;基于AMESim软件对混合动力传动系统的性能进行了验证,达到了预期的效果。

富水砂卵石地层水工隧洞衬砌用纤维混凝土性能评价

为了提高富水地段含砂卵石地层水工隧洞衬砌施工用混凝土材料的耐久性能,将钢纤维和聚丙烯纤维混合作为混杂纤维,分别评价了单一纤维和混杂纤维掺入时对水工隧洞衬砌用混凝土材料的力学性能和抗渗性能的影响。结果表明:在相同的配合比条件下,钢纤维和聚丙烯纤维的掺量越大,混凝土试件的抗折强度相对就越大,抗渗性能越强,而抗压强度则先升高后降低。混杂纤维的掺入能够更好地提升水工隧洞衬砌用混凝土的力学性能和抗渗性能,协同增效作用明显。综合考虑目标工程用混凝土的抗压强度、抗折强度和抗渗性能,推荐混杂纤维中钢纤维的最佳掺量为40 kg·m^(-3),而聚丙烯纤维的最佳掺量为4 kg·m^(-3)。研究结果认为钢纤维和聚丙烯纤维的掺入能够有效改善富水地段含砂卵石地层水工隧洞衬砌用混凝土结构的力学性能和抗渗性能,进而提高水工隧洞工程建设的质量。