Electrical power assisted steering for EVs and HEVs

Electrical power assisted steering (EPAS) is one of the key components, especially for electrical vehicle. It has attracted much attention for their advantages with respect to improved fuel economy and has been widely adopted as automotive power-steering equipment in recent years. EPS (electrical power steering) controllers contain MCU (microprocessor control unit) to implement the complex control algorithms. EPS control strategy development is the core technology of the whole system. To achieve the better performance of driving, both mechanical structures and electrical structures are totally designed as a whole. Model-based development is recommended to software design. There are several trends about EPS’ future, such as high power EPS development, high voltage EPS development and steering-by-wire technology.

Power-Assisted Cart Control Method with Motor Torque Limiter Based on Prediction of Torque Saturation

In this article, a method to control power-assisted carts with motor torque limiter that achieves the desired load-reduction ratio even if torque saturation occurs, is proposed to reduce the size and power consumption of power-assist systems. This method uses the ratio of the assist-force impulse to the operator-force impulse as an indicator for evaluating proposed method. Proposed method predicts the needs of the operator and delivers the desired load-reduction ratio by predicting operation. The results show that the target load-reduction ratio can be obtained with proposed control method and indicate that the target load-reduction ratio can be obtained with 80% force. By applying our proposed method, short available time of power-assisted carts will be improved.

Giving Girls Power Malawi girls get financial assistance to keep them in school

When the Malawian Government introduced free primary education in 1994, Joyce Mhango, then 13 years old, was in the same class as her brother in Mzimba, a small town in the north.

Microwave-Assisted Transition Metal Nanostructure Synthesis: Power-Law Signature Verification

A power-law (y = cxn) signature between process energy budget (kJ) and process energy density (kJ·ml-1) of microwave-assisted synthesis of silver and gold nanostructures has been recently described [Law and Denis. AJAC, 14(4), 149-174, (2023)]. This study explores this relation further for palladium, platinum, and zinc oxide nanostructures. Parametric cluster analysis and statistical analysis is used to test the power-law signature of over four orders of magnitude as a function of six microwave applicator-types metal precursor, non-Green Chemistry synthesis and claimed Green Chemistry. It is found that for the claimed Green Chemistry, process energy budget ranges from 0.291 to 900 kJ, with a residual error ranging between −33 to +25.9 kJ·ml-1. The non-Green Chemistry synthesis has a higher process energy budget range from 3.2 kJ to 3.3 MJ, with a residual error of −33.3 to +245.3 kJ·ml-1. It is also found that the energy profile over time produced by software controlled digestion applicators is poorly reported which leads to residual error problematic outliers that produce possible phase-transition in the power-law signature. The original Au and Ag database and new Pd, Pt and ZnO database (with and without problematic outliers) yield a global microwave-assisted synthesis power-law signature constants of c = 0.7172 ± 0.3214 kJ·ml-1 at x-axes = 0.001 kJ, and the exponent, n = 0.791 ± 0.055. The information in this study is aimed to understand variations in historical microwave-assisted synthesis processes, and develop new scale-out synthesis through process intensification.

Mass-Based Environmental Factor and Energy Assessment of Microwave-Assisted Synthesized Transition Metal Nanostructures

This paper describes mass-based energy phase-space projection of microwave-assisted synthesis of transition metals (zinc oxide, palladium, silver, platinum, and gold) nanostructures. The projection uses process energy budget (measured in kJ) on the horizontal axes and process density (measured in kJg−1) on the vertical axes. These two axes allow both mass usage efficiency (Environmental-Factor) and energy efficiency to be evaluated for a range of microwave applicator and metal synthesis. The metrics are allied to the: second, sixth and eleventh principle of the twelve principle of Green Chemistry. This analytical approach to microwave synthesis (widely considered as a useful Green Chemistry energy source) allows a quantified dynamic environmental quotient to be given to renewable plant-based biomass associated with the reduction of the metal precursors. Thus allowing a degree of quantification of claimed “eco-friendly” and “sustainable” synthesis with regard to waste production and energy usage.

LRU-Assist:一种高效的Cache漏流功耗控制算法

随着集成电路制造工艺进入超深亚微米阶段,漏电流功耗在微处理器总功耗中所占的比例越来越大,在开发新的低漏流工艺和电路技术之外,如何在体系结构级控制和优化漏流功耗成为业界研究的热点.Cache在微处理器中面积最大,是进行漏流控制的首要部件.LRU是组相联Cache最常用的替换算法,而研究发现,访存操作命中LRU后半区的概率很低.LRU-Assist算法以Drowsy Cache、Cache Decay等控制策略为基础,在保证处理器性能不受影响的前提下,利用既有的LRU信息把Cache的关闭率平均提高了15%,大大降低了漏电流功耗.

An Improved Torque Sensorless Speed Control Method for Electric Assisted Bicycle With Consideration of Coordinate Conversion

In this paper,we propose an improved torque sensorless speed control method for electric assisted bicycle,this method considers the coordinate conversion.A low-pass filter is designed in disturbance observer to estimate and compensate the variable disturbance during cycling.A DC motor provides assisted power driving,the assistance method is based on the realtime wheel angular velocity and coordinate system transformation.The effect of observer is proved,and the proposed method guarantees stability under disturbances.It is also compared to the existing methods and their performances are illustrated through simulations.The proposed method improves the performance both in rapidity and stability.

Experimental investigation of effects of airflows on plasma-assisted combustion actuator characteristics

The effects of the airflow on plasma-assisted combustion actuator （PACA） characteristics are studied in detail. The plasma is characterized electrically, as well as optically with a spectrometer. Our results show that the airflow has an obvious influence on the PACA characteristics. The breakdown voltage and vibrational temperature decrease, while the discharge power increases compared with the stationary airflow. The memory effect of metastable state species and the transportation characteristics of charged particles in microdischarge channel are the dominant causes for the variations of the breakdown voltage and discharge power, respectively, and the vibrational temperature calculated in this work can describe the electron energy of the dielectric barrier discharge plasma in PACA. These results offer new perspectives for the use of PACA in plasma-assisted combustion.

“印太战略”框架下美国对太平洋岛国的嵌入式援助

嵌入式援助是指一国在对外援助的过程中,利用本国的政治力量、社会力量和市场力量优势把本国的治理理念、规范制度、治理模式嵌入到受援国的治理架构中,重构受援国治理体系和治理能力,以深度影响受援国治理议程和政策偏好为目标的援助形态。近年来,出于制衡中国崛起、利用太平洋岛国的独特地缘战略价值、护持太平洋霸权和扩展软实力影响的战略需要,美国将太平洋岛国纳入其“印太战略”框架,着力实施嵌入式援助,推动太平洋岛国与美国实现战略耦合,呈现出多主体参与、全政府协同、注重治理经验输出、依赖联盟网络、采用项目外包和嵌入领域广泛的特点。美国的嵌入式援助在本质上就是以柔性、隐蔽和伪善的方式,试图在大国竞争中以治理软实力塑造太平洋岛国的美国认知、治理结构与对外关系,维护其在太平洋岛国的话语影响力和战略控制力,稳定由其主导的“印太秩序”。由于受到自身霸权相对衰落、部分太平洋岛国与美国存在利益冲突以及太平洋岛国的自主性增强等多重因素限制,未来美国对太平洋岛国的嵌入式援助成效将充满不确定性。

Review of Power-Assisted Lower Limb Exoskeleton Robot

Power-assisted lower limb exoskeleton robot is a wearable intelligent robot system involving mechanics,materials,electronics,control,robotics,and many other fields.The system can use external energy to provide additional power to humans,enhance the function of the human body,and help the wearer to bear weight that is previously unbearable.At the same time,employing reasonable structure design and passive energy storage can also assist in specific actions.First,this paper introduces the research status of power-assisted lower limb exoskeleton robots at home and abroad,and analyzes several typical prototypes in detail.Then,the key technologies such as structure design,driving mode,sensing technology,control method,energy management,and human-machine coupling are summarized,and some common design methods of the exoskeleton robot are summarized and compared.Finally,the existing problems and possible solutions in the research of power-assisted lower limb exoskeleton robots are summarized,and the prospect of future development trend has been analyzed.

乘用车双电机冗余电动助力转向系统研究

为了提高电动助力转向系统的安全性以及可靠性,基于乘用车提出一种双电机冗余电动助力转向技术,采用转向执行双助力电机,可以从硬件上实现冗余,避免任意单电机发生故障时导致转向系统的失效,不仅可以满足转向系统对于轻便型、助力跟随性的要求,还可以减轻单个助力电机的负载提高电机的使用寿命。针对提出的问题,介绍了对双电机阻力转向系统整体结构及工作原理,并对其关键零部件进行分析论述。搭建双电机冗余系统仿真模型,双电机电流分配采用“一主一辅”的控制方式,并进行方向盘多种工况仿真验证。针对助力转向出现抖动问题,结合“扫频试验”,设计输出转矩超前滞后补偿方式进行相位校正补偿。通过实车试验验证了该算法的准确性和有效性。实验结果表明双冗余电动助力转向系统极大提高了转向力矩的稳定性,抑制其扰动性,有较好的助力效果,极大提高系统的可靠性和安全性。

电动助力转向系统Carsim-Simulink联合仿真控制研究

电动助力转向系统作为电动汽车的主流配置,其性能好坏对整车转向操纵稳定性能有重要影响。以某款自主品牌电动汽车EPS系统为研究对象,进行动力学分析并依次建立Simulink子系统模型。根据实车参数,设计直线型助力特性曲线并输入前述模型,最终建立Carsim/Simulink联合仿真运动学模型并开展国标操纵稳定性仿真试验。结果表明:在方向盘转向角脉冲和角阶跃试验中,较无EPS助力控制车型,有EPS助力控制车型具有良好的车辆瞬态响应度和操纵稳定性;在转向轻便性试验中,验证本款车型助力特性合理,车辆具有较好的助力效果。

基于功率诊断的微波辅助点火能量沉积研究

基于功率诊断方法,研究了不同微波参数(脉冲波形和馈入延迟时间)下对微波辅助点火的增强效果,精确测量了点火过程中与火核耦合的微波能量,并分析了能量耦合的内在机制.结果表明:入射的部分微波能量以产生等离子体的形式耦合到点火火核中,耦合能量随微波脉冲功率的增大而提高,随延迟时间的增大而减小,最高耦合能量达到6.16 mJ;火核的增强效果与耦合能量的变化趋势一致,表明耦合的微波能量是点火增强的内在原因;能量耦合效率(耦合能量/入射能量)一般随脉宽和延迟时间增大而减小,最高耦合效率达到7.23%;并发现了微波能量耦合过程中存在从较低的效率转变到较高的稳定耦合效率的现象,将后者定义为饱和耦合模式;脉冲持续时间内到达饱和耦合模式的转变过程越短,能量耦合效率越高;饱和耦合模式下的能量耦合效率不受微波参数的影响,但高功率短脉宽的脉冲波形和低延迟时间能够更快达到饱和耦合模式,明显提高点火增强效果.

助力外骨骼机器人结构设计与运动学建模分析

为了实现日常生活助力功能,文中设计了轻型柔性助力外骨骼机器人的结构,下肢关节采用了主动驱动与被动储能元件相结合,膝关节设置驱动模块,髋和踝关节采用被动储能元件,根据仿生学原理设计人机绑缚装置,并对被动关节进行了节能验证,仿真结果验证了助力外骨骼机器人结构设计的可行性与助力功能的有效性。使用D-H方法建立了外骨骼机器人下肢运动学模型,以Opensim内的正常行走的关节角步态数据作为输入进行了正逆运动学的求解分析。建立外骨骼机器人的三维模型,添加行走时与地面的约束,进行物理模型的运动学仿真,结果证明了外骨骼机器人运动分析的可靠性。

社区矫正工作需要明晰的几个问题

社区矫正的价值理念和立法精神直接决定着社区矫正的制度建构。我国社区矫正制度应是以“教育矫正”和“融入社会”为特质的制度形态。教育帮扶则是做好社区矫正工作的核心和重中之重。从社区矫正的权力性质来看,社区矫正的权力属于特殊司法行政权的范畴,是公权力的表现形式,大致可划分为以下几个层次:社区矫正的刑罚执行权、社区矫正的刑事执法权、社区矫正的行政管理权。不同的权力分属于不同的社区矫正参与机关。刑罚执行是社区矫正的法律基础,是社区矫正工作开展的合法性依据;刑事执法是社区矫正的保障和前提,为有效开展社区矫正工作奠定基础条件;教育帮扶是社区矫正的主要目的和核心内容,也是《社区矫正法》的价值取向。

Green Chemistry Allometry Test of Microwave-Assisted Synthesis of Transition Metal Nanostructures

Microwave irradiation is considered an important approach to Green Chemistry, because of its ability to rapidly increase the internal temperature of polar-organic compounds that lead to synthesis times of minutes rather than hours when compared to conventional thermal heating. This works describes a dual allometry test for the discrimination between the solvents and reagents used in the microwave-assisted synthesis of transition metal (zinc oxide, palladium silver, platinum, and gold) nanostructures. The test is performed in log-log process energy phase-space projection, where the synthesis data (kJ against kJ·mol-1) has a power-law signature. The test is shown to discriminate between recommended Green Chemistry, problematic Green Chemistry, and Green Chemistry hazardous solvents. Typically, recommended Green chemistry exhibits a broad y-axes distribution within an upper exponent = 1 and lower exponent = 0.5. Problematic Green Chemistry exhibits a y-axes narrower distribution with an upper exponent = 0.94 and lower exponent = 0.64. Non-Green Chemistry hazardous data exhibits a further narrowing of the y-axes distribution within upper exponent = 0.87 and lower exponent = 0.66. In all three cases, the y-axes is aligned to original database power-law signature. It is also shown that in the x-axes direction (process energy budget) the grouped order of magnitude decreases from four orders for recommended Green Chemistry solvent and reagent data, through two orders for non-Green Chemistry hazardous material and down to one order for problematic Green Chemistry.

槽式太阳能辅助燃煤发电系统集成方式

针对某600 MW超临界发电机组,提出3种槽式太阳能辅助燃煤机组发电(SAPG)系统的集成方式.第1种为太阳能场并联取代高压加热器,第2种为太阳能场高压串联取代高压加热器,第3种为太阳能场低压串联取代高压加热器.利用Matlab编程建立槽式太阳能辅助燃煤电厂发电的仿真模型,在功率增大模式(PB模式)下仿真计算不同的集成方式热力性能,对3种集成方式下系统的太阳能发电量、光电转换效率、标准煤耗率等指标进行对比分析.结果表明,SAPG系统的3种集成方式随着太阳法向直接辐照度EDNI的增大,太阳能引入规模达到峰值为192.37 MW,太阳能发电量为59.55 MW,光电转换效率达到20.10%,标准煤耗率最低为264.44 g/(kW·h).当EDNI≤482 W/m2时,低压串联的集成方式下太阳能发电量、光电转换效率、标准煤耗率等指标均优于高压串联及并联集成的方式;当EDNI≥482 W/m2时,并联集成方式的热力性指标均优于其他2种集成方式,高压串联的集成方式热力性能指标最低.

车用高可靠性功率器件封装及辅助技术专辑主编述评

车用功率器件封装研究的进展极大提升了电动汽车的动力性能和续航能力,使得电动汽车更加高效、可靠。随着车用功率器件封装的不断优化,电动汽车行业有望迎来更广阔的市场前景和发展空间。近年来,功率器件封装建模、封装设计与优化、热管理与结温监测、器件驱动与应用、可靠性分析、在线监测等成为研究热点,并受到了学术界及工业界的持续关注。《电源学报》特别推出“车用高可靠性功率器件封装及辅助技术”专辑,以期推进车用功率器件及其应用难点和热点问题的探讨。

兆声功率密度对同轴兆声辅助喷射电沉积镍的影响

[目的]金属微器件在电沉积过程中往往会产生较大的残余应力,对微器件的尺寸精度、力学性能和良率产生不利影响。[方法]为降低镀层的残余应力,在喷射电沉积镍过程中施加同轴兆声辅助。研究了兆声功率密度对Ni镀层形貌、表面粗糙度、显微硬度和残余应力的影响。[结果]施加同轴兆声辅助后,所得Ni镀层的宏观和微观形貌都有所变差,表面粗糙度略微增大,显微硬度变化不大,但残余应力显著降低。当兆声功率密度为10 W/cm2时,Ni镀层的残余应力最低,比无兆声辅助时所得Ni镀层低了37.75%。[结论]在电沉积过程中施加兆声辅助能够有效降低镀层的残余应力。

黄桃低功率超声波辅助酶法去皮工艺优化

针对常见黄桃去皮方法能耗高、污染大、去皮效果不佳等缺点,该文以砀山黄桃为原料,利用能耗较低的低功率超声波辅助混合酶法进行去皮研究。以去皮后黄桃的去皮率与感官评价为研究指标,通过单因素试验得到最佳的工艺条件,并在单因素试验结果的基础上设计中心组合试验,采用响应面分析法进一步优化低功率超声波辅助下的酶法黄桃去皮工艺。结果表明,在pH值为3.55、温度45℃、超声时间47 min、混合酶质量浓度9.295 g/L、果胶酶与纤维素酶质量比7∶1条件下,去皮率与感官评分最佳,分别为(95±2)%和92±3。