高精度嵌入式超声波测距系统的研究

Research on High-precision Embedded Ultrasonic Ranging System 

摘要:

为了提高超声波测距精度,分析了超声波测距的原理,针对影响超声波测距精度的主要因素——环境温度,回波时间,从软件和硬件上提出了解决方法;软件上通过修正不同温度下的传播速度消除温度对测距精度的影响；硬件上设计升压驱动发射电路、由仪表放大器组成的信号幅度补偿电路和双比较器构成的回波检测电路以改善提高超声波质量和更好地确定传播时间;0.5~5 m的障碍物试验显示该系统的测距误差可限制在10 mm范围内；应用表明该系统稳定可靠,测距精度高,所以该系统具有一定实用价值。

Abstract:

In order to improve the accuracy of ultrasonic ranging, this paper analysis the principle of ultrasonic distance measurement, proposes the solution from the hardware and software in dealing with the main factors affecting the accuracy of ultrasonic ranging -the ambient temperature and the echo time. On the software by performing the propagation velocity correction at different temperatures in order to eliminate temperature’s influence to ranging accuracy; In hardware, the boost driver transmitter circuit, the amplitude compensation circuit of echo signal composed by an instrumentation amplifier and the detection circuit composed by an dual comparator has been designed to improve the quality of ultrasound and determine the travel time better. Experiment on obstacles between 0.5 m and 5 m shows that ranging error of the system can be limited within the scope of 10 mm; Application shows that the system is stable and reliable, and highly accurate, so the system has certain practical value.