運用直流電源載波設計車用超音波驅動與接收測距系統

Design of Automotive Ultrasonic Driver and Receiver Ranging System by DC Power Line Carrier

賴文彬(Wen-Pin Lai) ； 鍾文耀(Wen-Yaw Chung)

《先進工程學刊》 9卷1期 (2014/01) Pp. 27-36

摘要

此論文研究40 KHz超音波驅動與接收回波之系統電路設計，應用在車用倒車系統電路，亦可應用在機器人、工業自動機台與汽車防撞系統等。此電路系統由一台電子控制主機與六組超音波驅動板所組成，主機與驅動板間之訊號使用正負電源兩線式直流電源線載波方式傳遞。由主機提供電源給超音波驅動板，並在正電源線上同時載入發射脈衝與回波訊號，此訊號波形再由主機的濾波電路與比較器電路，將類比訊號轉換成穩定之數位波形，輸入微控制器來判斷所偵測到的距離，再由蜂鳴器分30公分、60公分與90公分三段音調來警示距離。此系統電路中應用電源載波、訊號放大回授、單電源帶通濾波運算放大器、電壓追隨比較器、靜電防護與PIC18F73微處理器設計等技術。此論文使用40 KHz閉防水式超音波感測器，其特性為單顆感測器可同時雙向作發射脈衝與接收回波訊號。後續文中將敘述主機與超音波驅動板分別之硬體與軟體設計。

關鍵字

直流電源線載波 ； 發射脈衝 ； 回波 ； 餘振

並列摘要

This study investigates the circuit of 40 KHz ultrasonic driver and receiver echo system, which can be used in car reverse parking, robotics, industrial automation and automatic bump-shield system etc. This circuit consists of an Electronic Control Unit (ECU) with six ultrasonic driver boards and the signals are transmitted by both positive and negative power wire of DC Power Line Carrier (DC P.L.C.) between the Control Unit and driver boards. ECU provides power to the ultrasonic driver boards while pulse and echo signals are simultaneously transmitted on positive line. A band-pass filter circuit and comparator circuit will transform analog signal into stable digital signal by using microcontroller to detect distance, judge and alert with buzzer warnings in three different tones from the distances of 30 cm, 60 cm and 90 cm. The circuit of this system equips with power carrier, signal amplification feedback, single supply band-pass filter op-amp, voltage follower comparator, anti-static (ESD) protection and PIC18F73 microprocessor design technology. In this study, a 40 KHz closed water-proof ultrasonic sensors simultaneously transmitting pulse and receiving echo signals is illustrated as well as the descriptions to the hardware/software design of the Control Unit and the ultrasonic driver board are stated.

並列關鍵字

DC power line carrier ； transmit pulse ； echo ； ring