Dynamic Performance Simulation of Power Shift Clutch During Shift

Based on the theoretical analyses, the dynamic and mathematical models of the system were developed. The models were implemented in the ambit of the Matlab/Simulink environment, and an integrated simulation model was developed. The dynamic performance of the power shift clutch during engagement and disengagement was studied by using this assembly model. The sliding speed, torque transmitted through the clutch, and the rate at which energy is dissipated during the process were determined. Using this model, the calculation during simulation can be simplified. This lays a foundation for the dynamic performance research on the power train with the power shift clutch, and provides a powerful tool for developing an automatic, electronically controlled transmission.

Characteristics on Hydro-mechanical Transmission in Power Shift Process

To improve the vehicular power and acceleration performance and reduce the shift impact, the study of the characteristics on power shift is necessary. Based on the flexible hydraulic unit of hydro-mechanical transmission, this paper explores the feasibility of shift without power interruption. With the four models concerning displacement ratio, rotational speed, rotational torque and power at ideal shift point, the characteristics on power shift in different running conditions are analyzed, and the rules of power shift are revealed. The theoretical analysis and test results show that the hydro-mechanical transmission can shift without power interruption in different running conditions. Furthermore, there exists an ideal shift point in theory, at which point the cycle power in hydro-mechanical transmission can＇t be generated, and the impact on the system can be reduced to the minimum. However, if before or after this ideal shift point, a cycle power can be generated.

The Power Shift： National Anxiety, Territorial Dispute, and Trans-Regional Cooperation in Asia and the US Role

＂Power Shift＂ is used as the emerging Asia （emerging China and India） and declining US, European Union （EU） and Japan in the contemporary world. In parallel, it is used as raising territorial disputes and Xenophobia in Asia and Europe, especially in East Asia, Japan, China, and Korea. However, Asian economic development and high economic growth rate attracts the US and the EU to Asian region, not a conflict, and it demands Asian stable development, rather than unstable territorial disputes. Angas Maddison Statistics, International Monetary Fund （IMF） and World Bank also shows that China will surpass the USA by Purchasing power parity （PPP） based Gross domestic product （GDP） economically in 2015. The world of the 21st century is not unilateral, but multilateral or multipolar system, and the sift is already starting from the American continent to the Asian continent. How does it ensure the Asian stability and how does it guarantee the collaboration and prosperity between Asian countries and the world？ And how does the United States uses Asian pivot and Asian rebalance strategy？ The analysis of these policies are extremely important for considering the future of the world system. In this article, the author investigates the rise and fall of the great powers in the transition era, and develops economics, knowledge and science technology in the near future. Especially the author investigates the importance of making networks of the think-tanks, and to strengthen the relationship between nation states and regions under the conflict and antagonism.

Power Shifting in Japan

Japanese Foreign Minister Seiji Maehara resigned on March 6 after it was reported he had illegally accepted a donation from a South Korean supporter. Three days later, Maehara’s deputy Takeaki Matsumoto was named Japan’s new foreign minister. The Shanghai-based Jiefang Daily published an article by Lian Degui, Deputy Director of the Center for Japanese Studies of the Shanghai Institutes for International Studies, analyzing Japan’s ongoing political strife. The following is an excerpt from the article:

Reliability Analysis of Hydraulic Transmission Oil Supply System of Power-Shift Steering Transmission with GO Methodology

GO methodology is a success-oriented method for system reliability analysis. There are components with multi-fault modes in repairable systems. It is a problem to use the existing GO method to make reliability analysis of such repairable systems. A new GO method for reliability analysis of such repairable systems with multifault modes was presented. Firstly, calculation equations of reliability parameters of operators which were used to describe components with multi-fault modes in reparable systems were derived based on Markov process theory. Then, this new GO method was applied in reliability analysis of a hydraulic transmission oil supply system( HTOSS) of a power-shift steering transmission at low and high speeds. Finally,Compared with fault tree analysis( FTA) and Monte Carlo simulation,the results show that this new GO method is correct and suitable for reliability analysis of repairable system with multi-fault modes.

Fault diagnosis of power-shift steering transmission based on multiple outputs least squares support vector regression

A method of multiple outputs least squares support vector regression （LS-SVR） was developed and described in detail, with the radial basis function （RBF） as the kernel function. The method was applied to predict the future state of the power-shift steering transmission （PSST）. A prediction model of PSST was gotten with multiple outputs LS-SVR. The model performance was greatly influenced by the penalty parameter γ and kernel parameter σ2 which were optimized using cross validation method. The training and prediction of the model were done with spectrometric oil analysis data. The predictive and actual values were compared and a fault in the second PSST was found. The research proved that this method had good accuracy in PSST fault prediction, and any possible problem in PSST could be found through a comparative analysis.

A CLASS OF POWER BOUNDED GENERALIZED SHIFT

A necessary and sufficient condition for the generalized shift operator T = S-k - (a(1)((1)), a(2)((1)),...) x e(1) - ... -(a(1)((j)), a(2)((j)),...) x e(j) (j greater than or equal to k) on l(1) to be power bounded is obtained. Moreover,this note points out that the power bounded operator T = S - (1, 1,...) x c(1) can shift a basis of [e(j+1) - e(j)](j = 1)(infinity), and this basis is not equivalent to {T(n)e(1)} (infinity)(n=0).

Study of the EAST Fast Control Power Supply Based on Carrier Phase-Shift PWM

EAST （experimental advanced superconducting tokamak） fast control power supply is a high-capacity single-phase AC/DC/AC inverter power supply, which traces the displacement signal of plasma, and excites coils in a vacuum vessel to produce a magnetic field that realizes plasma stabilization. To meet the requirements of a large current and fast response, the multi- ple structure of the carrier phase-shift three-level inverter is presented, which realizes parallelled multi-inverters, raises the equivalent switching frequency of the inverters and improves the per- formance of output waves. In this work the design scheme is analyzed, and the output harmonic characteristic of parallel inverters is studied. The simulation and experimental results confirm that the scheme and control strategy is valid. The power supply system can supply a large current, and has a perfect performance on harmonic features as well as the ability of a fast response.

Global Power Structure Shifted and Transitional Multi-polarity Emerged

The world is facing the third important global power shift.The United States,EU, Japan,Russia,China,and the newly emerging power group are becoming the six big forces in the international center stage,while the former three forces and the latter three belong to two groups,waning and waxing respectively.The major shift in the global balance of power is bound to give rise to the transitional multi-polar configuration,which implies a shifting of leadership over the configuration,China and U.S.outweighing other forces,global issues looming large,homogeneity blending with heterogeneity,and a shifting center of world powers.The transitional multi-polar configuration is all about change,upon which China is one of the decisive forces.

Influence of Buffering Pressure Characteristics on Shift Clutch Engagement Process

The dynamic math model of shift clutch in engagement process was determined on the basis of hydraulic buffering valve and shift clutch of a power shift steering transmission. The influence of buffering pressure characteristic on shift clutch engagement process was analyzed. The study results could be used to the characteristics match of the shift clutch with the hydraulic system of the high speed tracked vehicle power shift steering transmission and the performance prediction.

动力换挡变速器液压换挡过程仿真与试验研究

为满足重型车辆换挡动力不中断、换挡平顺的需求,本文设计了重型车辆动力换挡变速器换挡控制系统,利用AMESim软件,从换挡液压系统出发,对变速器换挡模块进行搭建分析,考察了换挡过程中液压系统油压特性、整车车速、冲击度以及离合器C1/制动器C2滑摩功动态特性。仿真结果表明系统能够满足动力换挡的要求;此外,针对所设计的液压换挡系统进行了台架试验,对仿真和试验的结果进行对比,仿真结果表明:目标车速响应时间提前了2.67 s, C2油压响应时间提前0.09 s且切换时间减少了13%,C1油压响应滞后0.07 s且出现压力超调量;试验结果显示:油压稳定性较差且转矩曲线响应时间提前0.06 s,并且冲击度变化曲线振幅较大。试验结果与仿真结果基本一致,验证了仿真结果的准确性。

重型拖拉机全动力换挡变速箱自动换挡策略研究

以一种用于220 kW拖拉机全动力换挡变速箱为研究对象,基于经济性、动力性为控制核心制定了道路运输和田间作业(犁耕)模式的标准型自动换挡策略,在全动力换挡变速箱基础上实现全自动换挡。为进一步提升不同工况下自动换挡策略的工况适应性,制定了智能型自动换挡策略,在道路运输自动换挡策略中,以燃油消耗总量为优化目标,换挡点车速和换挡延迟时间作为设计变量,对控制策略进行优化;在犁耕作业自动换挡策略中,引入滑转率变化量和车速变化量2个修正参数,通过模糊控制规则实时修正换挡点车速。基于AMESim和Matlab/Simulink建立了拖拉机仿真模型,开展自动换挡策略仿真。仿真结果表明,相较于标准型自动换挡策略,道路运输工况下,拖拉机燃油消耗总量下降6.71%;犁耕作业工况下,换挡次数降低36.5%,燃油消耗总量下降2.85%。通过台架试验验证了道路运输模式自动换挡略的有效性。

高等教育强国建设的时代命题:逻辑进路与研究进展

高等教育强国建设是中国高等教育的时代命题,也是一个中国式的命题。解答这个命题应遵循的逻辑进路是,辨析当今各高等教育强国的基本特征及其发展路径,在知己知彼的基础上探究最适合我国的高等教育强国建设之路。十多年来,相关的研究已经取得了大量成果,但仍存在诸多若明若暗之处,因此需要在后续的研究中进一步理顺逻辑思路,更加注重高等教育强国建设的体系性、系统性、优质性、长期性问题,更加注重对自身弱点的审思,并以此作为探究高等教育强国建设之路的逻辑起点。

百年变局与大国关系的中长期演变

在百年未有之大变局视角下,大国力量最本质和持久的因素仍然是经济力量。看待中美经济力量变化时,既要重视短期变化,但更要重视长期趋势。从短期来看,中国经济总量赶超美国经济总量的速度有所减缓,但仍存在超越美国的可能。从长期来看,基于PPP测算的经济力量对比,将康德拉季耶夫周期和权力转移理论相结合,有助于更好地理解国际冲突和地缘政治变化。由于收入水平较低的国家基于上述两种算法会有不同的经济地位,而这种差别是造成近年来俄罗斯和印度在国际舞台上冲突性行动加剧的重要原因。日本因为熟悉政府能力与经济增长的复杂关系,倾向于低估中国的长期经济增长前景,进而导致日本在战略上始终追随美国。不过,俄乌冲突使美国组建包括欧盟、日本和印度在内的大联盟的成效大打折扣。

乌克兰危机下欧盟力量格局变化趋向及其影响

The outbreak of the Ukraine crisis has accelerated the adjustment and power shifts of the European Union.Germany does not play the role model as it used to,its willingness and ability to make contributions have declined,and it has become a follower rather than a leader in the crisis response.The “Atlanticists” dominate the EU,and the “Europeanists” are weakened.Germany's all-round dependence on the United States has increased.France has lost traction on the EU,the German–French axis is absent,and the Central and Eastern European and Northern European countries are gaining momentum.Compared with other EU institutions and member states,the status and influence of the European Commission has been enhanced,leading the sanctions against Russia,participating more in the common security and defense policy,and contributing to the geo-politicization of EU economic policies.These changes will increase internal disputes within the EU,weaken the EU's international status and influence,and reduce the stability and predictability of the EU's China policy.

无线电能传输系统恒流输出控制方法研究

此处提出了一种发射端控制的无线电能传输(WPT)系统输出恒流调节方法。该方法无需在接收端增加传感器和无线通信装置,即可实现对系统输出电流的调节,因此,能够减小接收端体积和重量。首先,建立WPT系统等效电路模型,考虑整流电路等效输入阻抗的电阻和电感分量,推导得到发射端电压/电流与负载电流之间的量化关系;然后,采集发射端并联电容电压有效值和输入直流电流值,并通过逆变器移相控制,实现系统恒流输出;最后,搭建WPT实验台架,实验结果表明:在变负载工况下,恒流控制精度在3%以内,动态调节时间小于200ms,从而实现了负载电流快速、精准的调节。

基于慢波基片集成波导的小型化移相功分器

针对移相器和功分器的功能融合设计,提出了一种基于慢波基片集成波导(Slow-Wave Substrate Integrated Waveguide,SW-SIW)的小型化移相功分器,两个输出分支等长带宽,可实现30°相移量.其中一个输出分支通过基片集成波导(Substrate Integrated Waveguide,SIW)实现,而另一个输出分支将互补开口谐振环(Complementary SplitRing Resonator,CSRR)加载在上层金属表面,代替传统SIW连续的金属表面,该CSRR由经典CSRR结构演变而来,同时为了降低由CSRR加载所造成的相位上的不稳定,在CSRR内部添加金属化通孔,实现SW-SIW,使得截止频率和相速度降低.测试结果表明,移相功分器在9.0~11.8 GHz频带范围内反射系数|S11|小于-10 d B,相对工作带宽为26.9%,插入损耗小于1.3 d B.两个输出端口的相位差稳定在30°±3°,幅度差小于1.4 d B,实现了等功率分配.所设计的移相功分器具有较小的尺寸和低制造成本,适合应用在相控阵天线中.

基于恒功率约束的换挡毂数控铣削加工控制系统设计与实现

【目的】汽车双离合变速箱(Double Clutch Transmission,DCT)的核心零部件换挡毂加工制造精度要求高,针对数控铣削工艺的非线性问题,通过优化切削参数,以提高生产效率及延长刀具寿命。【方法】以主轴负载恒功率为约束条件,设计一种基于模糊控制算法的铣削加工控制系统。采用CP1E N30作为主控制器、CX-programmer开发下位机程序、Kingview开发上位机系统,完成基于主轴功率信号反馈的智能控制器的开发。【结果】在XHK716加工中心机床上实现铣削工艺的恒功率控制,通过换挡毂粗铣B平面工艺过程的应用,可知实时功率保持在目标功率附近。【结论】该控制系统提高了铣削加工效率,实现了保护刀具的目标,对延长刀具寿命有较好的参考价值。

双芯移相变压器在主动配电网电压和潮流调控中的应用分析

双芯移相变压器可以有效控制线路电压和潮流,优化潮流分布,提高电网电能质量。针对分布式电源的高比例接入造成的主动配电网电压波动和偏差问题,以及对潮流大小、方向和均衡度的影响,文章研究了双芯移相变压器的拓扑结构和工作原理;然后分析了串联变压器和励磁变压器的具体结构和作用,梳理了移相变压器分别应用于电压调节和潮流控制时的档位控制策略;最后基于MATLAB/Simulink建立了详细的仿真模型,研究了双芯移相变压器的电压调节效果,并对双线路并联、两路电源并联供电、多路电源并联供电三种应用场景下的潮流控制效果作了比较。仿真结果表明,双芯移相变压器可以在有限的档位内将线路电压控制在允许范围;与双线路并联、多路电源并联供电应用场景相比,两路电源并联供电时的潮流均衡效果最好,潮流偏差最小,本研究为双芯移相变压器的广泛应用提供了参考。

一种量化因子改进型的模糊自适应PID控制算法

针对模糊PID控制下的动态性能问题,提出一种量化因子改进型的模糊自适应PID(Fuzzy-PID)控制算法。在模糊量化环节引入模糊论域量化因子在线调整函数,实现对模糊量化因子的实时调整;将传统PID控制、传统模糊PID控制和量化因子改进性模糊PID控制,分别在100 kHz和200 kHz的系统频率下,进行单位阶跃输入信号下的动态性能对比实验。结果表明:该算法在2种系统频率下均能实现无超调,调节时间不超过0.15 s,其动态性能相较传统控制算法具有明显提升。