速比离散型车辆加速-滑行式节油巡航策略

巡航过程的节油驾驶是汽车经济性驾驶技术的重要组成,其核心问题是节油巡航策略的辨识。为此,定量化地求解了速比离散型变速器车辆的加速-滑行式(Pulse-and-glide,PnG)节油巡航策略。将节油策略的辨识构建为一最优控制问题;由于发动机的油耗呈强非线性,且PnG策略的加速阶段与滑行阶段动力学特性不一致,导致该问题属于非线性切换型最优控制。采用拼接策略将该非连续问题转化为加速和滑行两段光滑子问题的组合,通过伪谱法实现对积分型性能函数和微分型状态空间方程的代数转化,从而将原最优控制问题转化为非线性规划问题,并进而实现发动机输出转矩、变速器档位、模式切换时刻等参数的数值优化。结果表明:对所研究的车辆,平均巡航速度在中速范围内,PnG策略相对匀速巡航具有显著的节油效果,最高节油率接近25%。最后分析PnG策略实现节油的物理机理,并对节油效果进行了实车试验验证。     

基于随机动态规划的混合动力履带车辆能量管理策略

混合动力履带车辆采用发动机—发电机组和电池组混合供电,必须设计满足车辆动力性和燃油经济性约束的能量管理策略。针对串联式混合动力履带车辆,提出一种基于随机动态规划的能量管理策略设计方法。以实车行驶试验数据为目标工况,将驾驶员功率需求抽象为随车速变化的马尔科夫过程。建立发动机—发电机组、电池组以及直流母线功率平衡动态模型。以目标工况中燃油消耗及电池最终荷电状态的偏差作为车辆的优化控制成本函数,建立车辆能量管理最优控制问题。采用策略迭代法求解以发动机转速、电池组荷电状态、车速和驾驶员功率需求为输入、发动机电子节气门为输出的最优控制策略。所得控制策略通过基于前向车辆模型的仿真以及行驶试验验证。结果表明,相对于原发动机多点控制策略,所得最优控制在满足目标工况同时,燃油经济性明显提高。     

基于hp自适应伪谱法的自主泊车路径规划

针对自主泊车路径规划最优控制问题求解收敛速率慢的问题,提出基于hp自适应高斯伪谱法的自主泊车路径规划方法。首先建立车辆运动学模型,并考虑自主泊车过程中避障约束和边界约束,再以泊车时间最短为性能目标函数,将自主泊车路径规划问题转化为最优控制问题。采用高斯伪谱法对最优控制问题进行离散化处理并采用序列二次规划进行求解,在求解过程中通过动态调整网格区间个数和多项式阶数实现提高求解收敛速率。根据实际场景选取4种工况并进行路径规划仿真,并将3种伪谱法进行对比分析,仿真结果表明hp自适应高斯伪谱法能够提升自主泊车路径规划最优控制问题求解收敛速率,同时该算法可以实现在狭窄泊车位内的泊车路径规划,通过实车试验验证提出的方法获得的自主泊车路径的有效性。     

PHEV转矩的自适应神经模糊推理系统分配策略

为了减小混合动力汽车的燃油消耗和减少尾气中有毒气体含量,提出了迭代动态规划与自适应神经模糊推理系统相结合的能量管理方法。建立了并联式混合动力汽车动力系统模型,以车速和加速踏板开度为依据给出了换挡策略;建立了能量管理问题模型,使用迭代动态规划方法求解了最优控制律,但是此控制律无法应用于车辆的实时控制;提出使用自适应神经模糊推理系统探索最优控制律与车辆状态间的非线性映射关系,根据车辆状态确定最优控制律,实现了最优控制律的实时控制。使用CCBC工作作为验证工况,与基于规则控制策略、等效燃油消耗最小方法相比,控制方法的百公里油耗分别减少了18.56%、3.93%,且有毒气体含量明显少于另外两种方法,证明了控制方法的优越性。     

混合动力汽车扭矩分配策略研究

混合动力汽车的燃油经济性是其优越于传统汽车的最重要特征,因而如何进一步降低油耗是混合动力汽车需要重点解决的问题。基于H平台插电式混合动力汽车的P2构型,分析扭矩分配中的关键影响因素即发动机比油耗及电机效率,引入等效比油耗和等效发电系数,提出一种基于系统效率最优的扭矩分配策略。该控制策略能够合理地将需求扭矩分配至发动机和电机,让发动机和电机的系统效率最优、等效油耗最低,从而降低混合动力汽车的油耗,提高燃油经济性。     

基于发动机在环重型车C-WTVC循环油耗影响性研究

以某款重型柴油车为研究对象,基于发动机在环平台采用C-WTVC测试循环,研究不同换挡策略和不同滑行阻力对油耗的影响。文中通过对高挡位、居中挡位、偏低挡位3种驾驶换挡策略和相同类别车辆选取最大、居中、较小3组不同滑行系数对循环油耗的影响分析。结果发现：驾驶换挡策略不同循环油耗最大偏差为4.4%,最小偏差为0.99%,高挡位驾驶换挡策略的循环油耗最低。市区道路采用低挡位驾驶换挡策略发动机输出功最小,市郊路况不同驾驶换挡策略做功无明显差异,高速路况采用较高挡位输出功最小;不同滑行阻力导致油耗最大偏差为16.46%,最小偏差为6.96%,油耗结果随着滑行阻力增大而增大。分析比较该测试循环市区路况与市郊路况中不同换挡策略、不同滑行系数的油耗试验结果差异,为重型车自动换挡系统的研发与提升燃油经济性提供借鉴。     

基于动态规划的增程式电动汽车优化控制

针对给定工况下增程式电动汽车燃料最优控制问题,提出了基于动态规划算法的全局优化控制策略。通过分析整车动力系统的能量流以及能源管理控制原理,建立了以蓄电池的荷电状态(State of Charge,SOC)为状态变量和发动机-发电机组成的增程器(Auxiliary Power Unit,APU)输出功率为控制变量的最优控制数学模型,并以油耗最低为目标函数,采用离散动态规划方法,建立动态规划递归方程,求解其最优控制策略。基于ADVISOR平台对整车进行仿真,仿真结果表明,与功率跟随式控制策略相比,基于动态规划的控制策略能够在蓄电池和APU之间合理地分配功率,可以有效提高增程式电动汽车的燃油经济性。     

Plug-in混合动力汽车能量管理策略全局优化研究

应用动态规划全局优化算法,针对并联式Plug-in混合动力汽车在不同行驶里程下的能量管理策略进行了全局优化研究。结果表明:车辆的行驶里程小于55km时应使用电动机为主的能量管理策略,当车辆的行驶里程大于55km时应使用发动机为主的能量管理策略;在动态规划最优控制下,车辆行驶里程为55km时整车经济性能最佳,行驶里程小于110km时整车平均等价油耗为2.7L/100km,相对于原型车经济性提高了近58%。     

基于瞬态插值修正的生态驾驶燃油消耗模型

生态驾驶是一种经济驾驶策略,其主要目标是降低车辆能耗。车辆油耗模型的建立为生态驾驶策略提供了依据。本文采用“稳态模型+差分校正”的思想建立了汽车生态驾驶的油耗模型。首先,将发动机转速和功率作为多项式稳态油耗模型的输入,使用最小二乘拟合获得模型参数,并基于贝叶斯准则选择最优稳态油耗模式;然后,引入瞬态差分校正模块以提高油耗模型的预测精度。     

重度混合动力汽车油耗和排放多目标实时最优控制

混合动力汽车在模式切换过程中发动机频繁起停造成三元催化器温度下降,催化效率降低,排放恶化。以重度混合动力汽车在NEDC循环工况下的燃油消耗与三元催化器出口处的HC/CO排放为多目标优化函数,依据庞特里亚金极小值原理,建立包含蓄电池荷电状态和三元催化器温度两个状态变量的目标泛函并对其求极值,得到最优控制策略。在此基础之上,将制动、停机工况的控制策略进行简化,以分析比较有、无发动机起停最优控制对整车油耗和排放的影响。基于Matlab/Simulink仿真平台建立整车动力学仿真模型,对得到的最优控制策略进行仿真验证,并与规则控制策略进行比较。结果表明,上述方法能对发动机起停进行优化控制以显著加快三元催化器起燃,整车燃油经济性和三元催化器出口处的排放也得到全局优化,相对于规则控制,Pareto解集各项指标均有明显改善。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

OPTIMIZATION METHOD ON IMPELLER MERIDIONAL CONTOUR AND 3D BLADE

An optimization method for 3D blade and meridional contour of centrifugal or mixed-flow impeller based on the 3D viscous computational fluid dynamics (CFD) analysis is proposed. The blade is indirectly parameterized using the angular momentum and calculated by inverse design method. The design variables are separated into two categories: the meridional contour design variables and the blade design variables. Firstly, only the blade is optimized using genetic algorithm with the meridional contour remained constant. The artificial neural network (ANN) techniques with the training sample data schemed according to design of experiment theory are adopted to construct the response relation between the blade design variables and the impeller performance. Then, based on the ANN approximated relation between the meridional contour design variables and impeller performance, the meridional contour is optimized. Fewer design variables and less calculation effort is required in this method that may be widely used in the optimization of three-dimension impellers. An optimized impeller in a mixed-flow pump, where the head and the efficiency are enhanced by 12.9% and 4.5% respectively, confirms the validity of this newly proposed method.