基于超声波传感器的移动机器人避障系统研究

针对移动机器人移动过程中会遇到各种障碍物并需要合理地避开,以移动机器人为平台,利用超声测距原理,以51单片机为核心设计硬件电路,设计了一种基于超声传感器的移动机器人避障控制系统.利用单片机对超声波传感器采集到的环境信息进行存储处理,特别是在避障系统控制算法设计基础上引入模糊控制理论,设计模糊控制器,并且利用Matlab软件对模糊控制器进行了仿真验证.     

高精度的超声波测距系统在移动机器人导航方面的应用

本文介绍一种用于移动机器人导航和避障的高精度的超声测距系统。该系统由AT89C51单片机、超声波发射电路、超声波接收放大电路、峰值时间检出点电路、环境温度采集电路构成,系统具有测量响应速度快、准确度高、性能价格比高等特点。     

基于小波变换的高精度测距系统设计及DSP实现

目的为了解决传统物流行业机器人避障系统中存在的测距精度低、抗干扰性差等问题。方法提出一种基于DSP的温补与小波阈值滤噪的高精度超声测距系统,包括DSP最小系统、超声波传感器、LCD显示模块、温度补偿电路和报警电路等。超声波测距系统通过实时采集环境温度来修正声速值,采用小波阈值变换算法对回波信号进行处理,以提升回波信号的信噪比和起始点锐度。结果应用CCS4.2软件与DSP芯片进行调试、实验,实验表明在距离0～1200 mm内,系统的测量误差为±4 mm。结论采用小波阈值变换算法和温补电路,提高了传统物流机器人避障系统的测距精度。     

基于Arduino多传感器的智能小车避障系统设计

本文主要针对智能小车存在的对松软界面难以检测和受环境影响大等缺点,提出并设计了一种超声波与红外避障传感器相结合的避障系统,可以实现全方位的自动避障。系统以Arduino为主控单元,通过多个传感器数据的采集,经由计算机算法控制,系统硬件的各个模块相互配合,可使系统具有较高的自适应能力。实验结果表明,设计的超声波与红外避障传感器相结合的避障系统可有效的实现避障。     

基于多传感器的移动机器人智能测控与定位导航

本文结合自行研制的ＴＨＭＲⅢ的多传感器测控系统，重点介绍基于超声测距技术的移动机器人室外环境寞方法，以及基于差分ＧＰＳ和磁罗盘－光码盘的智能校式组合定位系统。实验结果表明该系统具有定位精度高，避障性能好，鲁棒性强等特点。     

超声波传感器在智能汽车系统中的应用

主要阐述超声波传感器的测距原理,以及利用超声波距离模块、传感器和单片机一起构成超声波测距系统,并介绍该超声波测距系统的软件流程及超声波测距系统在智能汽车系中的多种应用。因超声波具有的独特的特性,使得超声波传感器越来越在生产生活中对保障行车安全,提高汽车智能化水平有重要意义。     

基于AT89C51单片机的超声波测距系统设计

本文介绍一种基于AT189C51单片机的超声波测距系统,阐述了超声测距系统的构成、工作原理,给出了硬件电路框图和软件编程的设计方法。该系统具有硬件结构简单、工作可靠、测量误差小等特点。     

一种动态环境下的移动机器人避障策略

以激光雷达作为主要的环境感知传感器,针对动态环境设计了一种移动机器人避障策略.根据激光雷达采集的实时环境信息,检测动静态障碍物并建立障碍物链表.采用底层反应式避障和高层动态避障相结合的策略,实现了动态环境下的避障.使用分布式的软件设计方法,提高了系统的实时性.通过自行研制的移动机器人MORCS-1进行了实验,实验结果验证了该策略的有效性.     

一种用于小型无人机避障的快速视差测距方法

为了实现小型无人机快速自主测距避障,在双目视差测距的基础上,提出了一种机载三目视差测距算法,利用三个视觉传感器测得的数据,推导出简单的距离公式.利用各传感器成像间的相关性,提出了一种加快图像识别方法,通过缩小对图像中障碍物像元的搜索范围,有效地减小了目标搜索运算量,加快了搜索速度,为小型无人机快速自主避障系统的研制创造了条件.     

一种超声波测距仪的设计与实现

针对液体、固体物体表面过于光滑,不易测量的状况,采用ATMEL公司生产的单片机AT89S52最小系统设计并实现了一种结构简单检测迅速的超声波测距仪。根据超声波在空气中的传播特性,重点讨论了超声波测距的数据处理方法、装置的硬件实现以及为提高测量精度采用的温度补偿方法。系统由单片机最小系统、温度测量电路、数码管显示电路、超声波发射接收电路、LED显示电路、报警电路组成。通过实验,表明系统测量工作可靠,有良好的测量精度和灵敏度。     

热交换器的分类及优缺点分析

热交换器是将不同温度介质之间的热量通过热传导的形式,由高温介质传递给低温介质,使介质达到生产所需温度的工艺设备,也可作为一种节能设备使用.通过对不同热交换器的结构分析,总结不同热交换器的优缺点、适用环境,为生产工艺设计人员及设备制造单位在选择可降低能耗、提高效率的设备上提供参考.     

聚苯胺及其复合物的制备和结构及形貌分析

通过化学氧化法分别制备盐酸,盐酸和十二烷基苯磺酸,碳纳米管(MWNTs-COOH)掺杂的聚苯胺,利用红外光谱,紫外光谱,扫描电子显微镜和透射电子显微镜对所制备聚苯胺的结构和形貌进行分析。分析不同掺杂物对聚苯胺的结构和形貌的影响;同时研究了超声波作用对聚苯胺形貌以及聚苯胺包裹MWNTs-COOH情况的影响。     

Modelling and computation of curing and damage of thermosets

The curing of thermosets is a complex process involving the transition from a fluid into a (visco-) elastic solid. This phase transition comes along with an increase in stiffness and a volume shrinkage of the polymer. The latter may lead to severe residual strains and stresses, which in turn can cause damage in the final, usually quasi-brittle material. In this contribution a constitutive model is developed which takes into account the curing of a thermosetting material together with the process-induced damage as resulting from curing shrinkage. The curing of the material is governed by a phenomenological hypoelastic constitutive equation which includes temporal evolutions for stiffness and volume shrinkage. Thermal and viscous effects are neglected in the present study. An isotropic gradient-enhanced damage model is adapted to describe the damage evolution. The curing-damage model is implemented into a finite element code and numerical examples for thermosetting materials demonstrate that the proposed model is capable to predict cure-induced damage in thermosets.     

Thermodynamic similarity and prediction of the properties and characteristics of substances and processes

Principles of the theory of thermodynamic similarity are considered in application to all aggregate states of a substance, including phase transitions, and to the change in dissipative structures in open systems.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 53, No. 5, pp. 709–716, November, 1987.     

Mechanisms of Corosion and Oxidation of Metals and Alloys

Selected topics in field of the study of the mechanisms of corrosion and of oxidation of metals or alloys are presented. The first part reports a new model for the mechanism of the breakaway oxidation of ferritic stainless steels in water vapour. The second part is devoted to the physico‐chemical aspects of oxidation and presents experimental methods useful in the kinetic modelling applied to two alloys, the zircalloy‐4 and an AlMg5 % in the liquid state. In the third part the physical and numerical modelling of the stress corrosion cracking behaviour in face‐centered cubic (fcc) alloys is detailed, which enables the study of the influence of macroscopic parameters (such as the temperature or hydrogen activity) on the fracture process.     

碳化硼陶瓷增韧补强和致密化研究现状及其展望

碳化硼陶瓷具有极高的硬度,然而其低韧性、低抗弯强度、难以致密化限制了它的广泛应用.已有一些研究集中于碳化硼陶瓷增韧补强和致密化,对这一方面国内外研究进展进行了归纳与评述,阐明各种增韧补强和致密化方法的优缺点,提出碳化硼陶瓷增韧补强和致密化研究值得发展的一些方向.     

Measurement and analysis of elastic and anelastic properties of alumina and silicon carbide

Measurements of dynamic Young's modulus, E, and damping as a function of temperature, T, were made for alumina and silicon carbide. The Young's modulus data were compared with some from the literature, and analysed in terms of a theoretical framework relating the Debye temperature, θD, with the elastic constants. For both materials this analysis yielded a ratio T₀/θ_D which was near 0.4, where T₀ is an empirical fitting constant for the plot of (E(0)−E)/T versus 1/T (E(0) is the value of E at 0 K). The analysis of the damping data in terms of an Arrhenius type dependence led to effective activation energies near kT, where k is Boltzmann's constant. This revised version was published online in November 2006 with corrections to the Cover Date.     

Preparation and characterization of phosphate and arsenate apatites of strontium and their solid solutions

Samples of phosphate and arsenate apatites of strontium and six of their solid solutions, spread over the entire compositional range, were prepared by a wet method. They were characterized by chemical, X-ray, electron microscopic and infrared analyses. The validity of Vegard's law established the homogeneity of the solid solutions.     

检定和校准证书的异同与应用

本文介绍了检定和校准以及证书的两点相同、五点不同之处,说明了对检定证书和校准证书的正确应用。