科创中国

The identification of maximum road friction coefficient and optimal slip ratio is crucial to vehicle dynamics and control.However,it is always not easy to identify the maximum road friction coefficient with high robustness and good adaptability to various vehicle operating conditions.The existing investigations on robust identification of maximum road friction coefficient are unsatisfactory.In this paper,an identification approach based on road type recognition is proposed for the robust identification of maximum road friction coefficient and optimal slip ratio.The instantaneous road friction coefficient is estimated through the recursive least square with a forgetting factor method based on the single wheel model,and the estimated road friction coefficient and slip ratio are grouped in a set of samples in a small time interval before the current time,which are updated with time progressing.The current road type is recognized by comparing the samples of the estimated road friction coefficient with the standard road friction coefficient of each typical road,and the minimum statistical error is used as the recognition principle to improve identification robustness.Once the road type is recognized,the maximum road friction coefficient and optimal slip ratio are determined.The numerical simulation tests are conducted on two typical road friction conditions(single-friction and joint-friction)by using CarSim software.The test results show that there is little identification error between the identified maximum road friction coefficient and the pre-set value in CarSim.The proposed identification method has good robustness performance to external disturbances and good adaptability to various vehicle operating conditions and road variations,and the identification results can be used for the adjustment of vehicle active safety control strategies.

基于沥青路面裂纹扩展行为,设计预切口小梁试件的疲劳试验,以模拟其复合裂纹扩展模式;以疲劳寿命指标来评价沥青混合料的抗裂性能,同时进行沥青混合料的低温弯曲试验和J积分试验,试验混合料采用4种低温性能差异显著的沥青胶结料.判别各项评价指标对试验混合料抗裂性能的鉴别程度,并分析沥青低温临界温度指标、低温弯曲试验指标、J积分试验指标与预切口小梁疲劳寿命的相关性.结果表明:以混合料疲劳性能为基准的混合料抗裂性能排序与沥青胶结料临界温度的排序一致,也与沥青混合料低温弯曲试验和J积分试验中能量指标的排序一致.

本文对生物反应工程教学中存在的问题进行了探讨,介绍了以STATISTICA作为教学辅助手段应用于生物反应工程教学.通过运用STATISTICA解决教学中遇到的计算问题,学生的学习时间得到了节约,实际应用能力也得到了提高.5年的教学实践证明,STATISTICA作为生物反应工程的教学辅助手段是可行的、有效的,可以极大地提升教学效果,提高学生分析实验数据的能力.

Now the optimization strategies for power distribution are researched widely,and most of them are aiming to the optimal fuel economy and the driving cycle must be preknown.Thus if the actual driving condition deviates from the scheduled driving cycle,the effect of optimal results will be declined greatly.Therefore,the instantaneous optimization strategy carried out on-line is studied in this paper.The power split path and the transmission efficiency are analyzed based on a special power-split scheme and the efficiency models of the power transmitting components are established.The synthetical efficiency optimization model is established for enhancing the transmission efficiency and the fuel economy.The identification of the synthetical efficiency as the optimization objective and the constrain group are discussed emphatically.The optimization is calculated by the adaptive simulated annealing(ASA)algorithm and realized on-line by the radial basis function(RBF)-based similar models.The optimization for power distribution of the hybrid vehicle in an actual driving condition is carried out and the road test results are presented.The test results indicate that the synthetical efficiency optimization method can enhance the transmission efficiency and the fuel economy of the power-split hybrid electric vehicle(HEV)observably.Compared to the rules-based strategy the optimization strategy is optimal and achieves the approximate global optimization solution for the power distribution.The synthetical efficiency optimization solved by ASA algorithm can give attentions to both optimization quality and calculation efficiency,thus it has good application foreground for the power distribution of power-split HEV.

糯扎渡水电站主体地下工程具有规模大、进度要求快、地质条件差、施工难度大等特点.长江勘测规划设计研究院对监理项目进行了"事前、事中、事后"全方位的监理控制;在"四控制、两管理、一协调"等监理工作中,抓住工程特点和重点进行控制,取得了较好成效.

糯扎渡水电站是澜沧江中下游梯级的核心工程,也是华能集团创建世界一流水电建设项目的试点工程.其工程规模巨大,面临的许多技术、施工难题超出了国内已有的技术储备.工程建设过程中,华能澜沧江水电有限公司立足管理创新、技术创新攻克了诸多技术及施工难题,为我国高心墙堆石坝及大型水电工程的建设积累了经验,为创建世界一流水电工程奠定了坚实的基础.