An algorithm and observability research of autonomous navigation and joint attitude determination in asteroid exploration descent stage

In this paper, an autonomous relative navigation and joint attitude determination algorithm in asteroid exploration descent stage is researched based on feature point information of perpendicular asteroid surface image observed by optical navigation camera, distance vectors from spacecraft to asteroid measured by three angled installed lidars and relative velocity increment measured by accelerometer when the relative distance vector to the centroid of asteroid can not be obtained. The inertial attitude of spacecraft is determined by sun vector, star vectors and inertial angular velocity respectively measured by sun sensor, star trackers and inertial reference unit. Also, in order to obtain measurement error model transferred from sensor noise, a covariance matrix solver considering error correlation is presented via the error model of normalized vector to first order. Numerical simulation and improved observability evaluation of filtering are undertaken to discuss the results of complete sensor observation and weak observation of lidars, and verify the effectiveness of the presented relative navigation and attitude determination algorithm.     

莱钢2#竖炉自控系统的应 用

针对莱钢2#竖炉存在的问题,对其自控系统进行升级改造,以确保系统稳定运行,提高生产效率。     

Guaranteed transient performance based control with input saturation for near space vehicles

This paper describes the design of guaranteed transient performance based attitude control for the near space vehicle(NSV)with control input saturation using the backstepping method.To improve the robust controllability of the NSV,the parameter adaptive method is used to tackle the integrated effect of unknown time-varying disturbance and control input saturation.Based on the backstepping technique and parameter estimated outputs,a robust attitude control scheme is proposed for the NSV with input saturation.A novel robust attitude control scheme is then proposed based on a prescribed performance bound(PPB)which characterizes the convergence rate and maximum overshoot of the attitude tracking error.The closed-loop system stability under both the developed robust attitude control schemes is proved using Lyapunov’s method and uniformly asymptotical convergence of all closed-loop signals is guaranteed.Finally,simulation results are given to show the effectiveness of both the proposed robust constrained attitude control schemes.     

A customised approach to determining the geomorphic effectiveness of small flood events in a regulated river

The construction of dams significantly alters flow and sediment regimes with subsequent deleterious effects on the morphological and ecological character of rivers. Effective experimental floods can ameliorate the downstream geomorphic impacts of dams. The traditional view is that large floods are required to perform effective geomorphic work, and the geomorphic outcomes of small floods are often overlooked. Many river restoration frameworks do not consider small floods. Yet, there is evidence that the hydrological characteristics that ameliorate specific geomorphic impacts in a river are unique to each river, and a customised approach to setting the right mix of floods (including small experimental floods) is needed. In this study, we modify an existing flood effectiveness model developed for large floods, for determining the geomorphic effectiveness of small floods in a highly regulated Australian river. Two flood classes were added to the model (medium peak stream power and moderate total energy expenditure), and the flood power characteristics were rescaled to reflect the relative difference in the magnitude of the small floods and the magnitude of the geomorphic work performed. Using a step‐wise approach, this customised model determined the geomorphic effectiveness of small floods. The best flood for ameliorating the geomorphic impacts of flow regulation had medium to long duration (10 to 51 days), high peak unit stream power (77 to 123 Wm^?2) and moderate to large total energy expenditure (78,600 to 342,320 × 10³ J). This approach to determining flood effectiveness for small floods is applicable to other geomorphically impacted river channels downstream of dams and can be used to inform experimental flood releases for geomorphic outcomes.     

一种基于并联机构的航天器姿态模拟装置的设计开发

航天器发射升空前进行地面测试和试验是航天器研制过程中的重要环节。文中针对一种基于并联机构的姿态模拟装置的设计开发,从位置分析、速度分析和虚拟样机的建造和仿真分析等方面对3UPS-PU并联机构进行研究,完成姿态模拟装置的设计,为航天器装配、试验和测试设备的设计提供一种新的思路。     

市场机制下建筑节能相关利益主体博弈研究

充分发挥市场机制对节能产品的调控作用是市场经济的基本内容。通过对建筑节能市场发展中存在的相关问题研究,发现我国建筑节能市场的外部性和信息不对称性是产生问题的根源。全面分析建筑节能市场中政府、开发商、消费者以及其他服务组织等利益主体对市场培育的核心作用,通过构建政府与开发商、开发商与消费者之间的动态博弈模型,研究相关利益主体进一步完善建筑节能市场应采取的对策。     

基于Sage-Hus a方法的旋翼姿态控制

针对传统IM U传感器信息融合方法对外界信息变化不敏感等问题,在分析陀螺仪噪声特性并建立基于A RM A模型的卡尔曼滤波器抑制陀螺仪随机噪声的基础上,将基于Sage‐Husa方法的卡尔曼滤波器作为信息融合算法,增强姿态解算系统的自适应性。为提高Sage‐Husa算法容错性能,提出一种加速度计可信性条件,根据总加速度与重力幅值、方向上的差异来判定是否进行姿态融合。在基于ARM Cortex M4内核的嵌入式系统上实现姿态解算和姿态控制系统,在自制四旋翼飞行器半实物仿真平台上进行的实验结果表明,以上方法降低了姿态静态及动态解算误差,提高了姿态系统状态的跟踪性和适应性,满足复杂运动环境下姿态控制的需求。     

水上无人机自主着水控制系统设计

针对水上无人机在高海况下的着水问题,本文在分析了不同着水阶段特性的基础上,提出了一种自主着水控制系统设计方案.该方案将整个系统分为速度控制子系统和姿态控制子系统.速度控制子系统包含速度动态逆控制器和油门切换模块,姿态控制子系统包含海浪滤波器俯仰角反步控制器、高度PID控制器、俯仰角切换模块和T-S模糊推理模块.其中,海浪滤波器能有效滤除受扰姿态角中的海浪高频扰动,避免了着水之后舵面的频繁抖动;俯仰角反步控制器采用指令滤波的反步法设计,有效缓解了高海况下的舵面饱和问题.最后,在不同海况条件下进行了仿真.仿真结果表明所设计的控制系统具有良好的控制性能.     

基于文本特征的短文本倾向性分析研究

语篇倾向性分析是倾向性分析的较高层次领域。根据文本篇幅和结构可以将语篇分为短文本和长文本。该文以网络商品评论作为样本研究短文本倾向性分析的特点和策略。根据倾向极性在文中的决定性因素的不同表现,短文本可以分为含显性归总句、含隐性归总句、含特征词以及一般文本四类,针对不同类别文本采用不同的处理策略。在此基础上,运用词典、规则的方法构建了语篇倾向性分析系统CUCsas,该方法在第四届中文倾向性分析评测(COAE2012)中取得了较好成绩。     

基于Android平台的保健食品移动监管系统

针对保健食品企业监管效率低以及管理模式的不健全, 提出一种基于Android平台的移动监管系统模式. 智能终端设备通过连接3G、4G等无线网络, 使监管人员在执法现场将采集的信息数据直接上传至服务器, 同时增设数据同步代理机制, 实时监听用户的离线和在线状态, 防止数据丢失, 再利用蓝牙无线通信技术实现监管数据的后台打印功能, 进一步简化执法流程. 本系统的应用实现了移动监管和移动办公的模式, 具有实际应用价值.