【作者】 郝强；

【导师】 孟庆浩；

【作者基本信息】 天津大学 ， 检测技术与自动化装置， 2007， 硕士

【摘要】 距领域。为了获得更多的环境信息,通常采用多个超声换能器组成传感器环。传感器环上相邻换能器之间会产生超声串扰现象,导致错误的距离测量。常用的消除超声串扰的方法分为两种:基于启发式的软件处理法和基于硬件的编码法。为了消除超声串扰,本文在对现有文献进行研究和实验分析的基础上做了以下工作:1.总结了该领域的研究现状,在对超声串扰问题进行分析的基础上,找到了解决问题的切入点。2.利用DC-DC激励超声换能器。与原变压器激励模式相比,有效地减小了系统振荡。3.采用ARMA模型建立了超声测距系统的数学模型,在此模型基础上对该系统电路特性进行了研究,并对不同的激励方式做了比较研究。4.基于ARMA系统模型对脉冲宽度调制、频率调制和相位调制等方法进行仿真,分析了三种调制方式的传输特性,并比较了各自的相关结果。5.通过对不同长度序列的仿真分析,给出了序列长度与序列相关性之间的关系;对于短序列相关性不易确定的问题,引入了短序列相关栅格图的概念。更多还原

【Abstract】 Ultrasonic sensors have been widely used in the feild of mobile robotics for distance measurement with resonable cost and modest system’s complexity. In order to provide mobile robots with more environmental information, normally a sensor ring with multiple ultrasonic transducers is required. Crosstalk phenomenon, which can result in erroneous distance measurement, often occurs among adjacent transducers on the sensor ring. Two different kind of methods have been used by researchers to eliminate ultrasonic crosstalk, which are called heuristics based soft-processing method and hardware based code method, respectively.The following work has been done in this thesis.1. The state of arts of eliminating of ultrasonic crosstalk is summarized. The cut-in point is found to solve the ultrasonic crosstalk problem.2. The ultrasonic transducer is excited by the circuit based on DC-DC module. The system oscillating time is effectively reduced, compared with the transformer based drive mode.3. The Mathematics model of the ultrasonic range system is built. The circuit characteristic is studied based on this model and different triggering methods are compared.4. Pulse width modulation, frequency modulation as wel as phase modulation are simulated by the system model. These modulating methods are analyzed and their correlation results are compared.5. By analyzing the correlation results of sequences with different length, the relationship between length and correlation value of sequences is presented. To overcome the unpredictability of short sequence correlations, the concept of correlation gridmap of short sequence is put forward.更多还原