一种面向声兼容设计的主动声呐发射波形优化方法

针对多部舰载主动声呐同时工作时产生的声兼容问题,在现有波形设计方法的基础上,文章提出一种综合考虑特定频带功率谱和自相关旁瓣级的波形设计方法。波形设计时以舰载平台不同主动声呐工作频段作为先验知识,利用基于快速傅里叶变换(Fast Fourier Transform, FFT)的相位编码阻带循环算法(Stop Cyclic Algorithm-New, SCAN),综合考虑发射波形的功率谱和自相关旁瓣,引入惩罚函数,设计出一种同时兼顾特定频段功率谱陷波和相关旁瓣的发射波形。计算机仿真结果表明,SCAN 算法设计后的发射波形可根据实际工作需求,通过对惩罚函数权重因子的控制,来实现对主动声呐发射波形任意工作频段功率谱抑制或发射波形自相关旁瓣的降低,从而有效减小舰载平台多部主动声呐同时工作产生的相互干扰。     

一种新的半主动控制策略--频率控制

在半主动控制策略—主动变刚度(AVS)的基础之上,提出了一种新的半主动控制策略。利用短时最大熵谱谱阵分析方法能准确给出变频信号在较短时间序列中的时频信息,进而提出主动变刚度体系的频率控制算法。仿真分析表明,该方法简便可行,鲁棒性好,在线计算量很小,能有效的控制受控结构相对位移反应,因此工程实际应用的前景非常光明。     

结构振动主动控制的混合仿真和实时控制系统设计

本文针对结构振动主动控制问题构造了基于PC机和DSP的混合仿真和实时控制系统.设计这套系统的目的是要实现在结构振动主动控制中集数据采集、信号处理、模型辩识、控制器设计、多目标优化、控制仿真和实时控制等多功能为一体的计算机辅助控制器设计系统.由于这套系统在仿真和实时控制中均利用了DSP,使得仿真结果更接近于实际的控制效果,因而提高了控制器的开发效率,有利于进一步的实际应用.     

电气设备的主动保护与控制技术研究

在电气设备状态感知技术的支撑下,提出一套优化电网保护与控制的方法。基于电气设备对运行可靠性的感知,提出了主动保护对电网安全运行和供电可靠性的意义;基于电气设备对控制可靠性的感知,提出了优化控制决策、主动应对控制风险的技术理念;并对电气设备的主动保护与控制技术的应用前景进行了展望。     

结构随机振动混合控制整体优化

建立了与随机振动主动控制等价的随机振动混合控制系统方程,选取混合控制中主动外加能源指标函数最小为优化目标,实现了在物理空间的随机振动混合控制整体优化;在对结构模态参数灵敏度分析的基础上,给出了模态空间内实现混合控制整体优化的方法。对受零均值平稳白噪声激励的建筑结构实施混合控制整体优化方案,计算结果表明当被动控制部分合理设计时,主动控制部分所需外加能源指标将显著下降。     

《一种频域载荷识别的优化方法》

从优化的角度出发，利用遗传优化算法得到频域载荷谱，使得其产生的响应谱与实际的测量结果之间的误差足够小，这样可以认为所得到的载荷谱也就反映了实际的激励，即达到了载荷识别的目的，仿真结果说明了这种优化方法的有效性。     

隔震桥梁地震反应的最优主动控制力特性研究

采用经典二次型LQR主动控制算法,研究隔震桥梁支座处主动控制装置的控制力特性.研究表明:主动控制力主要表现为阻尼力;当采用适当的状态反馈控制向量及控制权矩阵时,主动控制力与支座的速度基本接近线性关系.在此基础上,提出了基于主动控制算法的隔震桥梁最优被动粘滞阻尼器设计方法.被动粘滞阻尼器的最优阻尼系数既可以由LQR的控制增益直接得到,也可以通过线性拟合在实际地震波作用下的主动控制力与速度的关系曲线得到,且二者的结果极为接近.进一步的仿真分析结果表明,优化的被动粘滞阻尼器完全可以达到主动控制的减震效果.     

车辆主动悬挂的最优控制研究

本文在传统的车辆悬挂设计方法的基础上提出了一种主动悬挂的最优自适应控制方法:首先利用优化方法找出悬挂参数与激励(路面谱与车速)之间的最优对应关系,而激励的大小又可通过车身振动加速度来反映,从而推导出根据车身振动加速度反馈来调节悬挂参数的一种新的最优自适应控制方法.仿真计算结果表明该控制方法是有效的,也是易实现的.     

基于可控性柱面网壳结构主动控制作动器布置的优化研究

利用磁致伸缩材料的磁控特性制作的作动器可以对结构进行主动控制。首先分析了这种作动器的工作原理和设计方法,并通过实验对其进行了输出性能测试。接着在对作动器进行动力学建模的基础上,推导出整个柱面网壳结构的作动控制方程,同时基于作动效率,提出了不依赖于控制方法的位置优化准则,并且在综合考虑控制效果系数、硬件成本和系统复杂性等因素的基础上,初步确定了作动器的数量,然后采用遗传算法,对作动器的布置位置进行了优化。最后利用LQR主动控制算法,对一柱面网壳模型结构进行了主动控制分析。结果表明,通过优化布置的作动器能够有效地减小结构的动力反应,是一种较好的主动控制方法。此外,主动控制模拟结果也验证了应用遗传算法优化此类问题的优越性和可靠性。     

结构地震响应控制的优化方法

针对大跨空间结构地震响应主动控制,以超磁致伸缩材料为核心元件设计了一种可以应用于大跨空间结构振动主动控制中的超磁致伸缩作动器,制作出了作动器的原型并对其进行了输出性能测试。使用遗传算法对大跨空间结构主动控制作动器的布置位置进行了优化设计,最后进行了优化效果的数值模拟分析。以此验证了超磁致伸缩作动器具有良好的作动效应,利用遗传算法在大大提高结构主动控制优化设计效率时,可以保证实现对结构的整体优化以及作动器能高效、经济地实现对结构进行主动控制的目的。     

PMSM馈能系统硬件在环仿真研究

为对电动汽车动力电机馈能效率进行研究,方便馈能效率的测量,提出一种基于滑模控制算法的PMSM(permanent magnet synchronous motor)馈能研究方法,即通过控制电动机的输入电压与电流来驱动相同性能的电动机发电。首先以馈能理论为基础,建立包含滑模变结构控制、空间矢量、PMSM等模块的PMSM馈能系统仿真模型,并进行离线仿真分析。结果表明:采用所提出的馈能方法可达到70%左右的馈能效率,具有一定的可行性。同时,建立PMSM馈能系统dSPACE硬件在环试验平台,对其进行硬件在环试验验证。试验结果表明:电动机馈能效率在60%~80%的范围内,与离线仿真所得结果较为接近。这不仅验证了所建立的馈能仿真模型的正确性,且进一步证明了纯电动汽车动力电机自身馈能在节能方面的可行性。所提出的馈能方法能够为目前现有馈能方式提供更多选择,硬件在环试验研究也能够为后续的PMSM台架和实车试验研究提供一些技术支持。     

Mitigating driver distraction with retrospective and concurrent feedback

OBJECTIVES: An experiment was conducted to assess the effects of retrospective and combined retrospective and concurrent feedback on driver performance and engagement in distracting activities. BACKGROUND: A previous study conducted by the authors showed that concurrent (or real time) feedback can help drivers better modulate their distracting activities. However, research also shows that concurrent feedback can pose additional distractions due to the limited time and resources available during driving. Retrospective feedback, which is presented at the end of a trip (i.e., post-drive), can include additional information on safety critical situations during a trip and help the driver learn safe driving habits. METHOD: A driving simulator study was conducted with 48 participants and 3 conditions: retrospective feedback, combined feedback (both retrospective and concurrent), and no feedback (baseline case). RESULTS: The feedback conditions (retrospective and combined) resulted in faster response to lead vehicle braking events as depicted by shorter accelerator release times. Moreover, combined feedback also resulted in longer glances to the road. CONCLUSIONS: The results suggest that both feedback types have potential to improve immediate driving performance and driver engagement in distractions. APPLICATION: Combined feedback holds the most promise for mitigating the effects of distraction from in-vehicle information systems.     

Students' Conceptions of Tutor and Automated Feedback in Professional Writing

Background Professional writing is an essential outcome for engineering graduates and hence a vital part of engineering education. To provide a successful learning experience for students engaged in writing activities, timely feedback is necessary. Providing this feedback to increasing numbers of students poses a major challenge for instructors. New automated systems work towards providing both timely and appropriate writing feedback, but students' views on automated feedback, and feedback in general, are not well understood. Purpose (Hypothesis ) To contribute to a deeper understanding of students' conceptions of feedback from tutors and an automated system called Glosser, and how these conceptions are related to achievement. Design /Method Students in an engineering course worked in pairs to write an engineering report on e‐business. The design of the study involves in‐depth interviews and the analysis employs an approach in which student conceptions of automated feedback are investigated in relation to related feedback from their tutor, perceptions of automated feedback in general, and their academic achievement. Results Students' conceptions of feedback vary and can be grouped into cohesive and fragmented, which is consistent with other theoretical models. Close associations were found between more cohesive conceptions of feedback and better academic performance. Conclusions A student's conception of traditional and automated feedback is similar, being either cohesive or fragmented. Changing one may change the other. Deep learners see feedback as a way of learning about the topic whereas shallow learners see them as a way to improve the communication aspects of writing. Design considerations based on these results are discussed.     

基于过程体验的信息反馈交互设计

目的探索在大信息时代良好信息交互体验过程中的反馈交互,研究以过程体验为核心的微交互及整体产品反馈感知下的交互设计路径,论述在体验时代,用户由功能导向到体验感知的转变,并探索具体交互设计方法。方法深入分析信息产品交互反馈的过程,剖析用户在与信息交互中所关注的重点,从用户体验要素、感知、决策行为的过程,探索信息交互反馈等各个要素的特征,从交互过程中总结交互反馈的侧重点,通过微交互、整体交互反馈以及具体案例及demo测试进行验证。结论信息产品交互过程中交互反馈体验优劣直接影响体验整体感知,直接影响产品粘性,构建以过程体验为中心的信息交互反馈设计框架,要从反馈的具象、上下文、动效等视角阐释,注重细节过程,注重交互反馈的构成构建,综合运用增强交互反馈良好过程性的体验要素完成信息产品交互反馈的设计指导建议。     

假肢交互中振动反馈的设计方法

目的 完成假肢交互中振动反馈的设计方法,选择合适的振动反馈信号,为假肢反馈端的设计提供科学依据。方法 选择振动作为反馈信号,通过人机交互实验测量不同振动强度下人体的差别阈限,模拟截肢者在振动反馈下使用假肢完成任务的过程。结果 得出相应的用户数据并对其进行分析,在实验结果基础上提出假肢交互中振动反馈的设计方法。结论 振动对于人体是一种新的信号,截肢者可以通过训练逐渐掌握振动反馈,提升其对假肢产品的认同感,将假肢真正作为自己身体的一部分。以振动反馈的设计流程为例所提出的振动反馈的设计方法,为假肢产品反馈端的信号选择提供了包括用户灵敏度、人体对交互方式的适应期和用户的心理学数据等量化信息,提升截肢者对假肢产品的体验。     

Spatial beam profiles from a laser-diode system with optical feedback: the importance of interference

The output beam profile of a laser diode with weak-to-moderate levels of optical feedback is shown to arise from interference of the emitted and feedback fields. This has been determined from a series of experiments, that measure the output spatial beam profile as the optical feedback field into the laser diode is spatially manipulated. Tilting, focusing, and aperturing the feedback field led to output beam profiles readily interpreted as the interference between the emitted and the feedback fields, provided the output of the laser-diode system with optical feedback has sufficient temporal coherence. Observation of the interference pattern in the spatial beam profile, at an appropriate level of optical feedback, can be used to study the relative wave front of the optical feedback and emitted fields and to estimate coupling coefficients.     

Chinese truck drivers' attitudes toward feedback by technology: a quantitative approach

This study examined Chinese truck drivers' attitudes toward receiving feedback about their driving performance by in-cab technology and explored the best ways of providing feedback to truck drivers in China. The similarities and differences between US and Chinese drivers were also compared. Survey data were collected from 200 long-haul truck drivers in China to provide quantitative information. The results of the current study were compared to the results of a previous study published in 2006 which utilized focus group discussions with Chinese truck drivers, and to the data of a similar survey conducted in the US and published in 2005. Results of the current study showed that Chinese truck drivers were eager for more feedback about their driving performance and they were willing to receive feedback from technology. Although negative feedback was most prevalent in their working environment and was considered acceptable if it improves driving safety, they considered positive feedback as more helpful to safe driving. They perceived many benefits of receiving feedback by technology and comparatively few drawbacks and concerns. Compared to US truck drivers who strongly preferred feedback from a human (e.g., safety director, dispatcher) rather than from technology, Chinese truck drivers were more positive in terms of receiving feedback from technology. They considered feedback from technology to be more objective and scientific than feedback from humans. This study showed the importance of considering cross-culture differences when planning to apply interventions in different countries and cultures.     

电脑式微波炉控制面板按键反馈类型的比较研究

本实验是对电脑式微波炉控制面板中按键反馈类型的比较研究,其目的是确定较优的按键反馈类型.实验采用了系列目标任务的方法,结果表明:视觉反馈、听觉反馈和视听反馈三种反馈类型的操作绩效之间无明显差异,但均优于无反馈条件下的操作绩效,而被试主观评价的数据表明,视听反馈是三种反馈类型中较好的一种.     

移动应用反馈机制中的隐喻设计研究

目的研究移动应用反馈机制中的隐喻设计,以期提高反馈机制的质量和效率,增强移动应用的友好性。方法从认知隐喻观出发,论述了隐喻在反馈机制设计过程中应用的重要作用,并从设计类型和设计方法两个方面,对移动应用反馈机制中的隐喻设计进行了研究。结果总结出了移动应用反馈机制中的隐喻设计类型和设计方法。结论依据移动应用反馈机制的内容和表现形式,选择合适的隐喻设计类型和设计方法,有助于构建运作良好的交互设计反馈机制,提升移动应用的用户体验。     

互联网产品设计中反馈机制的研究

从反馈机制的角度出发,分析了视觉反馈、听觉反馈、触觉反馈等反馈种类以及功能,阐述了反馈对互联网产品的重要意义,通过对互联网产品的信息反馈进行对比分析,得出互联网产品中存在的一些问题。在此基础上,提出了进行反馈功能的设计时,要使反馈掌控时间和用户心理,反馈要避免粗暴和带来信任,应该尽量使用丰富的非模态视觉反馈,以及合理使用正面听觉反馈。