On Dual-Mode Driving Control Method for a Novel Unmanned Tractor With High Safety and Reliability

Due to the non-standardization and complexity of the farmland environment, it is always a huge challenge for tractors to achieve fully autonomy (work at Self-driving mode) all the time in agricultural industry. Whereas, when tractors work in the Tele-driving (or Remote driving) mode, the operators are prone to fatigue because they need to concentrate for long periods of time. In response to these, a dual-mode control strategy was proposed to integrate the advantages of both approaches, i.e., by combing Self-driving at most of the time with Tele-driving under special (complex and hazardous) conditions through switching control method. First, the state switcher was proposed, which is used for smooth switching the driving modes according to different working states of a tractor. Then, the state switching control law and the corresponding subsystem tracking controllers were designed. Finally, the effectiveness and superiority of the dual-mode control method were evaluated via actual experimental testing of a tractor whose results show that the proposed control method can switch smoothly, stably, and efficiently between the two driving modes automatically. The average control accuracy has been improved by 20% and 15% respectively, compared to the conventional Tele-driving control and Self-driving control with low-precision navigation. In conclusion, the proposed dual-mode control method can not only satisfy the operation in the complex and changeable farmland environment, but also free drivers from high-intensity and fatiguing work. This provides a perfect application solution and theoretical support for the intelligentization of unmanned farm agricultural machinery with high safety and reliability.      

吸收浓度对玻璃态膜中气体吸收过程影响的研究

通过气体在玻璃态高分子膜中的吸收过程分析,认为在膜中气体分子与膜之间的相互作用将影响吸收等温线。假设气体在膜中的溶解过程类似于在溶液中的溶解过程,推导得出了普遍化双方式吸收模型。该模型中考虑了气体吸收浓度对气体在玻璃态膜中吸收过程的影响,几乎能够描述各种吸收过程。     

铁氧体双模器件的广义理论

铁氧体双模器件包括双模移相器,圆极化移相器,旋转场移相器.双模变极化器等等.其种类繁多,每种器件由若干基本双模段级联而成.每个基本单元上,外加磁场形式各不相同,有四磁极磁化场,纵向磁化场,双磁极磁化场及其混合磁化场.本文拟用统一的理论对其进行处理及分析并引入具体实例使用CAD技术进行计算,从而进一步确认理论的正确性.     

采用超导材料设计制作窄带宽双模微带滤波器

本文采用双面高温超导薄膜设计制作了一种窄带宽双模微带滤波器,介绍了高温超导滤波器的工作特点和性能优势,给出了四阶双模微带滤波器的设计过程、设计结果。滤波器制作于以0.5mm 厚度铝酸镧（LaAlO3）基片为衬底的双面高温超导DyBCO 薄膜上,中心频率为2017.5MHz,通带宽度为15 MHz,滤波器的测试结果与设计结果较好吻合。     

Development of highly photoluminescent electrospun nanofibers for dual-mode secure authentication

The photochromic phenomenon has been recently used as a fascinating technology in the development of highly efficient anti-counterfeiting materials with dual-mode security encoding of concurrent photochromism and fluorescence emission. Herein, we successfully developed lanthanide-doped aluminate nanoparticles (LAN)/polystyrene (PS) electrospun nanofibers as novel secure authentication films. Different ratios of lanthanide-doped aluminate nanoparticles were mixed with polystyrene-based copolymer solutions in N,N-dimethylformamide (DMF) and subjected to electrospinning to afford photochromic and fluorescent nanofibers. The generated electrospun nanofibers demonstrated a narrow diameter distribution, a smooth surface and well-defined morphological properties. The produced smart nanofibers were applied onto cellulose paper sheets to demonstrate a dual-mode secure strategy with a simple and rapid authentication. LAN was prepared in the nano-scale for better dispersion in PS, which guarantee the formation of transparent films. LAN was studied by transmission electron microscope (TEM) and X-ray diffraction (XRD). LAN displayed diameters of 5–12 nm. On the other hand, the fibrous diameters of LAN-PS samples were studied by scanning electron microscopy (SEM) to indicate diameters of 200–300 nm. The induced security marking was invisible (363 nm) under visible daylight turning into visible green (520 nm) color under ultraviolet irradiation demonstrating a bathochromic shift. Both excitation and emission displayed high intensities. The security marking was fully reversible under ultraviolet/visible irradiation cycles without fatigue. Those advantageous properties could be attributed to the high surface area of the chromogenic nanofibrous films to result in high absorption of light leading to strong optical dual-mode photo-responsiveness. The generated LAN-PS hybrid films showed improved hydrophobic properties with increasing LAN. The nanofibers showed transparency, stretchability and flexibility. The present strategy can be reported as an efficient technology to develop many anti-counterfeiting products toward a better market with social and economic values to avoid fake products.     

车用复合无级变速器行星排组拓扑分析

基于正反双向分汇流行星排组的一类新型复合无级变速器系统具有效率高、功率容量与速比变化范围大等特点。根据其基本工作原理采取适用的方法，对其正反双向行星排组可选用的36种拓扑布局方案进行了详细的比较分析，并筛选出了适于车用的推荐拓扑布局方案。     

NOVEL COMPOSITE CVT SYSTEMS WITH DIVERGING AND DUAL-MODE CONVERGING POWER FLOW

A new type of composite CVT(continuously variable transmission) systems featured bypower flow divergence and dual-mode convergence, capable of improving CVT's efficiency and powercapacity or making A-MTS(automated manual transmissions) become continuously variable, is studied.With specific mechano-mechanical and electromechanical composite CVT systems as detailed exam-ples, its basic working principles are expatiated. General methods and key points in designing andrealizing such systems are also analyzed and discussed.     

双模椭圆球面波多载波索引调制解调方法

该文在基于信号分组优化的椭圆球面波函数(PSWFs)多载波调制的基础上,引入双模索引调制思想,提出了双模PSWFs多载波索引调制解调方法(DM-MCM-PSWFs).该方法利用未被激活的剩余部分子载波加载第2星座图产生的调制符号,以传输额外的信息比特,实现了基于信号分组优化的PSWFs多载波调制中频谱资源的进一步利用,...     

基于基片集成波导(SIW)的双模带通滤波器

首先介绍了基片集成波导(SIW)这一新技术,并用表面电流理论解释了电磁波在SIW中的传输模式。同时,通过使用凹型过渡和接地共面波导过渡两种转换方式,解决了基片集成波导与微带线的过渡问题,从而解决了滤波器和有源微波电路的集成问题。文章用这两种过渡方式,分别设计了中心频率在5.63GHz和5.45GHz的双模带通滤波器。实验表明:这两种滤波器在通带内的反射损耗S11均优于-21dB,-3dB带宽都在50MHz以上。     

A dual-mode fast-transient average-current-mode buck converter without slope-compensation

A dual-mode fast-transient average-current-mode buck converter without slope-compensation is proposed in this paper. The benefits of the average-current-mode are fast-transient response, simple compensation design, and no requirement for slope-compensation, furthermore, that minimizes some power management problems, such as EMI, size, design complexity, and cost. Average-current-mode control employs two loop control methods, an inner loop for current and an outer one for voltage. The proposed buck converter using the current-sensing and average-current-mode control techniques can be stable even if the duty cycle is greater than 50%. Also, adaptively switch between pulse-width modulation (PWM) and pulse-frequency modulation (PFM) is operated with high conversion efficiency. Under light load condition, the proposed buck converter enters PFM mode to decrease the output ripple. Even more, switching PWM mode realizes a smooth transition under heavy load condition. Therefore, PFM is used to improve the efficiency at light load. Dual-mode buck converter has high conversion efficiency over a wide load conditions. The proposed buck converter has been fabricated with TSMC 0.35 μm CMOS 2P4M processes, the total chip area is 1.45×1.11 mm². Maximum output current is 450 mA at the output voltage 1.8 V. When the supply voltage is 3.6 V, the output voltage can be 0.8-2.8 V. Maximum transient response is less than 10 μs. Finally, the theoretical analysis is verified to be correct by simulations and experiments.