以谱分解方法对随机摄动系统进行最优性能分析

We investigate the best performance for linear feedback control systems in the case that plant uncertainty is to be considered. First, we define an average integral square criterion of tracking error over a class of stochastic model errors. By utilizing spectral factorization to minimize the performance index, we derive an optimal controller design method and further study best performance in the presence of stochastic perturbation. The results can be used to evaluate optimal performance in practical control system designs.     

Path tracking control of autonomous agricultural mobile robots

In a tractor automatic navigation system, path planning plays a significant role in improving operation efficiency. This study aims to create a suboptimal reference course for headland turning of a robot tractor and design a path-tracking controller to guide the robot tractor along the reference course. A time-minimum suboptimal control method was used to generate the reference turning course based on the mechanical parameters of the test tractor. A path-tracking controller consisting of both feedforward and feedback component elements was also proposed. The feedforward component was directly determined by the desired steering angle of the current navigation point on the reference course, whereas the feedback component was derived from the designed optimal controller. Computer simulation and field tests were performed to validate the path-tracking performance. Field test results indicated that the robot tractor followed the reference courses precisely on flat meadow, with average and standard lateral devia- tions being 0.031 m and 0.086 m, respectively. However, the tracking error increased while operating on sloping meadow due to the employed vehicle kinematic model.     

一种宽带高线性高增益功率放大器的研究与设计

倍频程宽带功率放大器是宽带射频前端的关键部件,在无线电通信、雷达、电子对抗设备中有着广泛的用途.在对晶体管进行分析的基础上,选择InGaP／GaAs异质结双极晶体管TQP7M9105,该晶体管是高线性、高增益的输出功率1W的驱动级功率放大器.设计带宽为400MHz-800MHz,在电路设计中采用新的负载牵引、源牵引仿真方法,在输入激励为12dBm条件下,设计带宽内增益达到19dB,带内波动±1dB,实验结果和仿真结果非常吻合.     

基于自动循迹小车的智能公交系统设计

本文采用STC12C5A60S2单片机作为核心控制单元,设计了基于自动循迹小车的公交系统,主要包括单片机控制系统,驱动电路、循迹电路、指挥控制中心等.通过实验测试,完成了语音报站,红绿灯自动识别,车辆防止追尾、车辆跟踪等功能.     

An adaptive ramp generator for ADC built-in self-test

An adaptive ramp generator based on linear histogram was proposed for the built-in selftest （BIST） of analog to digital convertor （ADC） in CMOS image sensor. By comparing the generated ramp signal to a reference voltage and feeding back a calibration signal, the slope adjustment was implemented, and high linearity and precision of ramp slope were realized. By modulating the pulse width and reference voltage, sweep length varied from microsecond to second and signal swing could reach 3 V with 5.6 mW power consumption. The ramp was used as input to an ideal 10-bit single-slope ADC, and the corresponding DNL and INL were 0.032 LSB and 0.078 LSB, respectively.     

Long-term effects of school-starting-age rules

To study the long-term effects of school-starting-age rules in a setting with early ability tracking, we exploit the birth month threshold used in the Netherlands. We find that students born just after the threshold perform better at the end of primary school than students born just before it. This translates into increased placement in high ability tracks in secondary education. This difference diminishes gradually during subsequent stages, and we find no effect on the highest attained educational level. Those born just before the threshold enter the labor market somewhat younger and have therefore more labor market experience and higher earnings at any age until 40. We conclude that early ability tracking does not harm long-term outcomes of children who were, for exogenous reasons, placed in a lower track.     

基于模型参考自适应的一类二维系统形状渐近跟踪控制

针对二维线性系统,探究可实现其状态轨迹形状与参考系统状态轨迹间形状渐近跟踪的控制方法。首 先,利用刚体运动描述系统状态轨迹的形状渐近跟踪概念,然后对传统模型匹配条件进行扩展。在该条件下,采用 Lyapunov 稳定性与模型参考自适应相结合的方法,设计形状渐近跟踪控制器。实验表明,该控制器可保证被控系统与参考系统状态轨迹达到形状渐近跟踪。与传统方法相比,所给出的模型匹配条件及形状渐近跟踪控制器适用范围更广。最后,对模型进行仿真实验,证明了该控制方法的有效性。     

The High School Schedule in Midwestern Secondary Schools

Abstract

The role of sensory feedback factors in determining learning and memory was investigated in terms of the effects of four different modes of movement control of sensory input on memory of stimulus patterns-i.e., (1) visual tracking of the pattern without manual control, (2) parallel pursuit tracking of the pattern with a hand-con- trolled visual cursor, (3) opposed pursuit tracking of the stimulus pattern with a hand-controlled visual cursor, and (4) compensatory negative feedback tracking in which the subject observed only the error of tracking the stimulus pattern. Results indicated that mode of sensory feedback control of sensed input of stimulus patterns during learning determined immediate memory, and that memory was superior for modes of feedback control in which the pattern of stimulation and of movement could be compared. The main conclusion was that the processes of active and passive learning and their role in determining learning and memory are specifiable and predictable as variable forms of movement-controlled sensory feedback.     

智能救援车系统的设计与实现

系统以凌阳SPCE061A单片机作为控制核心。采用SHARP公司的红外测距传感器GP2D12及自制高精度光电编码器,结合闭环反馈控制算法,可快速准确控制电动车驶出建筑物中曲折道路;采用自制的五路反射式红外寻线传感器,可轻松实现找线并寻迹行驶;自制高检测距离、大检测范用金属探测器,稳定地检测铁片,并通过控制电磁铁铁片拾取器拾取铁片,并准确放人指定位置．人机交互采用段码液晶SMS0403显示,并配有语音播报,超炫的光报警信号。电路设计时我们采用美国国家仪器NI Multisim电路仿真分析软件进行了电机驱动,金属探测器的设计与仿真．     

Control of orbit and control of chaos in a class of dynamic system

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一种基于视觉的车载照明自动跟踪系统

目前夜间事故勘察车载照明多采用传统自适应灯光,存在照射范围有限且调节照明方向繁琐等问题。因此,基于视觉设计一种车载照明自动跟踪系统。使用视觉处理技术与双步进电机控制对车载照明系统进行改进,以增强车载照明智能化和灵活性。针对传统自适应灯光需人为操纵照射目标的问题,车载照明系统在运行时对红外光源（移动目标）进行图像检测,实时反馈拍摄图像中红外光源位置坐标,再根据位置坐标信息控制双步进电机,带动车载照明灯准确地照射到红外光源坐标位置。实验结果表明,该系统可快速检测到照明目标位置坐标,准确控制步进电机移动,可满足跟踪目标的要求,准确率达 95%。     

两相混合式步进电机的模糊PI控制器设计

针对混合式步进电机高速反电动势大及恒流驱动控制技术在宽调速范围的电流跟踪控制不确定性问题,结合混合续流模式设计了酬机制,分析了两种常用的电流检测方案,并提出了一种基于模糊工程的模糊电流给定,模糊控制器最大输出占空比给定的PI控制方法。利用大电感电机进行了实验,实验结果表明：该方法能提高电机的运行速度,并在宽电压、宽调速范围均具有很好的电流跟踪控制效果,具备转速转矩的确定关系。     

基于状态观测器的非一致采样系统状态反馈预测控制

针对输入更新不等间隔的非一致采样系统,提出一种基于状态观测器的状态反馈预测控制算法．通过提升控制信号,设计了输入输出同周期的非一致采样系统的状态观测器,并且给出了提升控制信号前后观测器系数矩阵的关系．运用线性矩阵不等式方法,解决无穷时域二次型性能指标下的优化问题,给出了状态反馈预测控制器存在的充分条件．仿真结果证明了控制算法的有效性．     

模糊免疫PID控制器的研究

为了提高PID控制器的控制性能．分析了常规PID控制器和模糊控制器的控制特性,借鉴生物免疫反馈机理,引入了免疫PID控制算法。结合模糊控制理论在控制方面的优越性,设计了模糊免疫PID控制器．可以应用于具有时变、非线性、纯滞后、大惯性等类型的控制系统中．     

高校实验室安全快速跟踪反馈体系的设计

高校实验室量大面广,其创新实验风险高、安全管理技术性强,因此,快速跟踪反馈应是防范安全隐患及事故发生的有效措施之一。该文根据文献调研,梳理目前实验室安全管理中存在的共性问题,结合实验室实际,提出了"四级三层"实验室安全检查及督查机制,并在此基础上设计了实验室安全快速跟踪反馈系统。     

网络课程学习跟踪评价的实践探索

本文给出"现代教育技术基础"网络课程学习跟踪评价的结构图,以此为实例,结合笔者创建网络课程的经验,重点讨论了网络课程学习跟踪评价的意义、设计原则、实施途径和运行效果.     

静止同步补偿器的非线性控制

静止同步补偿嚣(STATCOM,Static Synchronous Compensator)是一个多变量、非线性、强耦合的系统,建立精确的换流器数学模型比较困难.本文采用非线性变换和非线性系统反馈线性化理论,建立同步旋转坐标系下STATCOM的非线性数学模型,结合线性系统最优控制原理,设计STATCOM的状态反馈线性化解耦控制器,实现有功功率和无功功率的解耦控制.基于PSCAD/EMTDC的数字仿真,验证了所设计的控制器具有良好的控制性能.     

CONTINUOUS ROBUST TRACKING CONTROLLERS FOR A CLASS OF UNCERTAIN NONLINEAR DYNAMICAL SYSTEMS

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论股份公司监事任免机制之完善

现代股份公司中,监事会制度非常重要。监事会能否有效地行使监督权,在很大程度上取决于其自身是否独立。监事任免机制在维持其独立性方面至关重要。德国、法国、日本、韩国和台湾省法律都详细规定了监事之提名、选举、任期与连任和解任。通过与这些国家进行比较,发现中国监事任免制度非常粗糙。因此,应借鉴这些国家的经验,对中国监事任免机制加以完善。     

中美苏战略大三角的结构现实主义分析

当今日中国一步步走向全球，再审视与当时两个超级大国同台共舞的点滴，显然在那段精彩演绎背后透露出的战略逻辑十分值得我们研究。以往对两国关系的研究多注重当前国际形势的分析及未来走向预测，较少涉及以历史的视角审视国家行为的根源。而本文从结构现实主义理论框架着手，通过对战略大三角的过程模式分析解读这一重大历史进程，并借助史实对战略大三角的形成，发展以及淡化来分析新现实主义在这一过程中的作用，不仅有助于我们正确地看待冷战以来虽饱经风雨却不断发展的两国关系，而且就未来进一步加深理解、拓宽合作以及提升双边关系不无裨益。