高精度超声波测距系统设计

在市场普遍使用的超声波测距系统的基础上,针对普遍存在的缺陷,从硬件和软件两方面对超声波测距系统进行了改进.在超声波测距发射和接收部分分别创新性地使用了MAX232和双电压比较器,用于提高测量精度,减小盲区.为了排除环境因素对声速的影响,系统加入了声速校验功能.通过实验验证,本系统有效地减小了盲区,增大了量程,可测范围为2～400 cm,提高了测量精度,保证误差在2～6 mm左右.     

基于超声波测距的煤矿井下皮带检测系统设计

设计一个基于超声波测距的煤矿井下皮带检测系统,通过在Proteus仿真软件中设计皮带检测系统电路,并与Keil软件中编写的C代码联合调试。当被测物体的距离小于限定的距离时,单片机会驱动蜂鸣器报警提示,从而实时检测皮带跑偏,确保煤矿安全生产。本系统结构简单、稳定性好、易于操控,并通过温度补偿功能来修正测距误差,提高了检测精度,且Proteus中通过的皮带检测电路,可移植到真实电路板上焊接,节约了生产成本,提高了煤矿的自动化生产效率。     

基于STC89C52单片机的超声波测距系统

为了实现对中短距离的测量,比如在智能小车避障、车辆定位中对前方的障碍物进行判断,利用主控器件单片机和一系列外围器件进行超声波测距系统的设计。具体设计包括超声波发射电路、超声波接收电路、液晶显示电路及温度补偿电路等硬件模块,并利用Keil C平台进行了相应的软件设计。其中在接收电路中设计的增益控制部分有效地解决了当回波信号过于微弱时系统测量误差加大的难题。在实验室对设计好的测距系统进行了实地性能测试,实验表明,系统的测距最大值为120 cm,测量精度为0.1 cm。     

超声波传感信号传输信道特性分析与测试

为了提高超声波避障测距系统的作用距离,对超声波信号检测与超声波传输信道、信噪比的关系进行了分析。将超声波传播特性与无线电波传播特性进行了对比研究,采用频谱测量的方法对超声波传输特性、信噪比特性进行了实际测试,并给出了提高避障测距系统作用距离的方法与建议。     

超声波定位系统的研究

采用超声波定位系统,在较小的局域空间对移动物体进行定位。为提高该系统的性能,采用如下措施:利用成熟的无线局域网技术传输数据,使传输数据稳定、可靠;用射频技术传输超声波发送和接收端的同步信号,从而提高了定位系统中的测距精度;利用病态数学和良态数学的理论指导参考点的布置,使得由于超声波测距误差对定位系统的影响控制在允许的范围内,从而进一步提高了定位系统的精度。超声波定位系统的定位误差一般不大于6 cm。该系统具有较高的性价比,可满足在多种局域环境中对移动物体进行定位的精度需求。     

基于Arduino单片机的汽车并线辅助系统设计

为有效减少道路交通事故发生率,最大限度保护驾驶员和乘客,以Arduino Mega 2560单片机为核心,结合HC-SR04超声波测距模块设计了一种汽车并线辅助系统。该系统在运行过程中模拟真实路况,利用超声波原理,当驾驶员开始拨动转向灯杆准备做并线或者超车的动作时,系统启动检测汽车后视镜盲区及相邻车道后方是否有正在行驶的车辆;当超声波测距模块检测到相邻车道后方有行驶的车辆,并且与该车辆的车距小于设定的安全值时,系统启动报警模块,主动对驾驶员发出危险报警,驾驶员根据报警系统的提示以及后视镜的情况判断是否可以安全并线。该系统具有测量精度高、性价比高、改装方便的优点,对汽车安全驾驶有着良好的辅助作用。     

基于单片机的智能小车的设计与实现

介绍了一种以 STC89C52单片机为控制核心的智能小车的设计。设计由电机驱动模块、超声波测距模块、循迹模块、红外和语音模块组成,拟实现一个无人驾驶公交车系统。通过 C 语言编程实现小车的前进倒退、转向行驶、自动循迹导航、超声波测距,并根据检测障碍物距离调整速度、红外遥控定点播报功能,实现智能控制,达到设计目标。该系统电路结构简单、功耗低、稳定性高,具有一定实际应用价值。     

车载可视倒车装置的设计与实现

车载电子产品中能够将影音整合在一起的产品将是未来发展的主要趋势,不仅能够帮助驾驶员更清晰地看清障碍物图像,也能够进行距离检测。在STM32单片机的硬件平台上开发了智能型汽车倒车影像和超声波测距系统,采用摄像头模块和超声波测距模块分别进行图像和距离信息的采集,并实时地传送给STM32单片机,单片机处理后,将障碍物图像显示在显示屏上,同时该装置能根据车辆倒车时与障碍物的距离进行不同声音的预警,其目的在于减少倒车的安全隐患,帮助驾驶员扫除视野死角和视线模糊的缺陷,有助于保证驾驶员的倒车安全性。     

一种基于LPC935的超声波测距系统设计

介绍了一种基于LPC935的超声波测距系统,利用超声波传感器,采用渡越时间法TOF,用LPC935进行控制、计算、显示测量数据,经实验该系统可实现0.10-10.00 m的测量范围,并能够清晰稳定地显示测量数据.可以应用于汽车倒车、建筑施工工地以及一些工业现场的位置监控等场合.     

基于单片机的超声波测距系统的设计与实现

超声波具有易于定向发射、反射性好、传播速度远小于光速而便于测距等特点。文章充分利用超声波这些特点,设计并制作了基于单片机AT89C51的超声波测距系统,该系统可在208cm有效范围内测定距离并显示,经反复测试测量误差不大于2cm;超声波测距可以应用于智能避障、汽车交通等系统中。     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

汉字倒说

汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

钱生钱!

我们绝大部分人都同意一件事情——我们喜欢金钱。但是你对金钱的喜欢之情足够到让你创立一份事业么?.财富通常被人忽视,主要在于人们不能真正了     

Social and Cultural Influence on Word Meaning

Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language.     

Inequalities for inscribed simplexes

The problem on the geometrc inequalities involving an n-dimensional simplex and its inscribed simplex is studied. Aninequality is established, which reveals that the difference between the squared circumradius of the n-dimensional simplex andthe squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not lessthan the 2(n-1)th power of n times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is atangent point one. Deduction from this inequality reaches a generalization of n-dimensional Euler inequality indicating that thecircumradius of the simplex is not less than the n-fold inradius. Another inequality is derived to present the relationship betweenthe circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.