超声波测距系统硬件电路的研究与设计

发布时间：2019-02-18 10:34

【摘要】：超声波测距是一种非接触式的检测方式。与其它传统的光学检测或者电磁学检测方法相比较,超声波测距不受光线、被测对象颜色等因素的干扰,尤其适用于被测物在烟雾、大量粉尘、电磁干扰或致毒等极端恶劣环境下的测量。本文基于超声波测距在倒车雷达中的应用,对超声波测距硬件系统进行了细致地研究和设计。本文首先阐述了超声波测距在倒车雷达应用中的意义以及超声波测距的现状和发展,并介绍了超声波的基本特性和超声波测距的工作原理,同时分析了超声波在空气中传播的衰减特性,着重研究了自动增益控制技术的分类和基本原理,利用可变增益放大器与D/A转换器构成了自动增益控制电路,根据传播距离的远近程控设置不同的增益。其次介绍了超声波测距的整体框架,设计了超声波测距的发射电路和接收电路。其中,发射电路利用中周变压器提高超声波发射功率,驱动收发一体式超声波传感器发射出超声波信号;接收电路根据超声波回波极其微弱的特点设计了放大滤波电路,包括第一级低噪声放大电路、带通滤波电路、自动增益控制电路、A/D转换等模块,给出了每个模块的设计电路。超声波测距受温度影响较大,系统设计了温度补偿模块,实时补偿超声波传播速度,提高测距精度。根据版图设计原则,设计了硬件系统版图。最后,对超声波测距板进行测试和调试,实验表明,本文设计的超声波测距硬件系统测距范围为20cm～5m,测距精度为3mm。本文提出的自动增益控制技术提高了系统的测距精度,能够实现精确测距。
[Abstract]:Ultrasonic ranging is a non-contact detection method. Compared with other traditional optical or electromagnetic detection methods, ultrasonic ranging is not interfered by light, object color and other factors, especially when the measured object is in smoke, large amount of dust, etc. Measurement in extremely harsh environments, such as electromagnetic interference or poisoning. Based on the application of ultrasonic ranging in reversing radar, the hardware system of ultrasonic ranging is studied and designed in detail. In this paper, the significance of ultrasonic ranging in the application of reversing radar, the current situation and development of ultrasonic ranging are described, and the basic characteristics of ultrasonic wave and the working principle of ultrasonic ranging are introduced. At the same time, the attenuation characteristics of ultrasonic wave propagation in the air are analyzed, and the classification and basic principle of the automatic gain control technology are emphatically studied. The automatic gain control circuit is constructed by using the variable gain amplifier and the D / A converter. Different gains are set according to the distance of propagation. Secondly, the whole frame of ultrasonic ranging is introduced, and the transmitting circuit and receiving circuit are designed. The transmitting circuit uses the middle cycle transformer to improve the ultrasonic transmitting power and drives the integrated ultrasonic sensor to send out the ultrasonic signal. According to the extremely weak characteristics of ultrasonic echo, the receiving circuit has designed amplifying and filtering circuits, including the first stage low noise amplifier circuit, the bandpass filter circuit, the automatic gain control circuit, the A / D conversion module and so on. The design circuit of each module is given. Ultrasonic ranging is greatly affected by temperature. Temperature compensation module is designed to compensate the speed of ultrasonic propagation in real time and improve the accuracy of ranging. According to the layout design principle, the hardware system layout is designed. Finally, the ultrasonic ranging board is tested and debugged. The experimental results show that the ultrasonic ranging hardware system designed in this paper has a ranging range of 20 cm ~ (5) m and a range of 3 m ~ (m). The automatic gain control (AGC) technique proposed in this paper improves the accuracy of the system and can achieve accurate ranging.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB559

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