Design of Millimeter Range High Precision Ultrasonic Distance Measurement System

On the basis of analyzing the main error sources of ultrasonic distance measurement, a millimeter-range high-precision ultrasonic distance measurement system was developed. The STM32 processor was used as control core of the system. We chose 200 KHz transmitting-receipting ultrasonic transducer and increased the environmental temperature compensation and back wave gain compensation. Meanwhile, the study proposed a method without additional hardware circuit which using STM32 processor to measure the pulse width of the echo wave, correct the lag time of the echo and further improve the accuracy of measurement. The experimental results demonstrated that ranging accuracy was less than 1mm in the range of 1000 mm with the conditions of using air as medium and existing the good reflective object. The system has simple and reasonable structure, with good stability, convenient measurement, high precision and could be suitably applied to the field of high precision measurement.