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。     

汽车超声波雷达辅助泊车系统开发

采用STC89C52RC单片机作为汽车超声波雷达辅助泊车系统的控制器,配合超声波测距模块HC-SR04实现超声波测距功能,辅助驾驶员泊车。为了补偿超声波传播速度受温度变化的影响,使用DS18B20温度传感器测取环境温度,提高测距精度。在液晶显示器(LCD)显示测距结果的同时,使用语音播报模块ISD1700播报实测距离,改善用户的使用体验。系统的有效测距范围为0.2cm~250cm,1m以内测距误差小于1cm,100cm~250cm内测距误差小于3cm。     

一种超声波测距装置的设计与实现

超声波测距技术应用广泛,可应用于汽车倒车、建筑施工工地以及一些工业现场的位置监控等。重点介绍了一种基于单片机的超声波测距装置的设计与实现。包括电路的基本组成及设计原理,超声波测量模块的接口特性及基本功能,软件设计原理以及测量精度的控制等。     

基于超声波传感器的风管清扫机器人避障功能设计

为解决风管清扫机器人在工作过程中容易与风管壁面发生碰撞的现象,本文利用超声波测距技术实现了机器人的自动避障功能。首先,介绍了HR-SR04超声波集成模块的测距原理和距离校正实验。其次,介绍了机器人自动避障功能的实现方法和自动避障功能在机器人上的应用。最后,为了检验风管清扫机器人避障功能的效果,进行了相应的测试实验。实验结果证明了超声波模块能够很好地完成风管清扫机器人自动避障功能。     

基于超声波测距的汽车倒车报警器

详细介绍汽车倒车测距报警器结构.硬件模块由超声波发送接收装置、ATB9C51单片机、报警电路及显示电路组成.超声波测距报警器较其他报警器具有电路简单、操作简便、工作稳定可靠等优点,可实现无接触式测量.本设计成本低廉,性能优良,市场前景极为广阔,对提高我国汽车工业实际水平.具有较大的实践意义.     

移动机器人超声波测距和避障系统的设计及实现

本文介绍了移动机器人的超声波测距和避障系统的设计方案,以及系统的软、硬件组成.该系统的硬件电路以DSP-TMS320LF2407A作为核心处理器,包括超声波测距模块,以及外围辅助电路.系统采用了多路超声波传感器共同作用来完成整个机器人系统的避障和路径规划.在移动机器人的360度的方向上等角度每隔45度安装1个超声波传感器,共8个.各个方向上的超声波传感器循环工作,使得移动机器人实时获取距障碍物的距离和方位信息.样车实验表明,该系统可以满足移动机器人室内避障的要求.     

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。     

超声波测距误差分析及修正方法

在介绍超声波测距原理的基础上.分析了超声波传播速度与环境温度的关系,重点简述了影响渡越时间测定的因素,以及回波窜绕问题,进而提出了提高测量精度的方法.这对减小超声波测距误差有一定的现实意义.     

摊铺机平衡梁的超声波测距系统的设计

本文提出了一种单片机+CPLD+模拟电路的超声波测距系统,单片机只负责读出数据并进行运算和通讯,模拟电路用来发出和接受超声波信号,CPLD专门用来测距,测距中的时间是通过高精度的晶体振荡器作为时钟信号源来进行计数的,可实现高精度和同步测量.     

基于单片机的超声测距系统

介绍并设计一种基于单片机的超声测距系统。该系统以超声波的传播速度为确定条件.利用发射超声波与反射回波时间差来测量待测距离。概述超声波检测的基本原理。并且在介绍超声测距系统功能的基础上,提出系统的总体构成。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...