基于STM32单片机的高精度超声波测距系统的设计

摘要

提出了一种基于STM32单片机的超声波测距系统的设计方案。与传统单片机相比,STM32的主频和定时器的频率高达72 MHz,提高了时间测量的分辨率。在开启定时器计时的同时,启动PWM通道驱动超声波发射器和输入捕获通道捕捉回波信号,提高了测量的精度。在充分分析超声波测距产生盲区和误差原因的基础上,设计了时间增益补偿电路（TGC）和双比较器整形电路分别测量远、近距离,并通过软件算法对回波信号进行峰值时间检测,简化了电路。实验研究表明,该系统测量精度达到了1 mm,盲区低至2.5 cm。%An ultrasonic distance measurement system based on STM32 Microprocessor is presented.Compared with the traditional microcontroller,the basic frequency and the Timer frequency of the STM32 microcontroller reach up to 72MHz,which improve the resolution of the measuring time.The superiority is that you can start PWM channels to drive ultrasonic transmitters and input capture channel at the same time.The time gain compensation（TGC） circuit and the double comparator plastic circuit are used to reduce the blind area and error.In addition,using the peak time detecting technique through the software algorithm,the arrival time of ultrasonic echo can be correctly detected.The experiments show that the system measurement accuracy can reach to 1mmand the blind area low to 2.5cm.