本論文研究針對雙頻式超音波測距系統，進行最佳化研究。承襲前代提出的雙頻式演算法，本文將其實際應用於測距系統中，並進行完整的性能分析與實驗。雙頻式超音波測距是由傳統式測距改良而來，傳統式測距的誤差會隨距離拉長而增加。雙頻式測距發送兩個不同的頻率，利用相位差，回推超音波第一個波前，改善傳統式測距的缺點。本論文提出雙頻式測距所需的相關參數最佳化設定，達到最佳的量測結果。 經由實驗之結果，傳統式超音波測距的實際量測，最大誤差達到50.21mm。雙頻式超音波測距在最佳化的設定下，最大誤差改善至7.6mm。第一頻超音波發送後，必須等待4.652ms以上，才可發送第二頻超音波，避免兩者能量耦合。 This paper deals with the research on the optimization of using the dual frequency method of ultrasonic distance measurement system. Following the research of dual frequency method algorithm, this paper implements it on the ultrasonic distance measurement system and performs complete experiments and analysis. The dual frequency method is improved from the traditional measurement method. The measurement error of the traditional method rises with the increase of distance. Dual frequency method uses two ultrasound waves in slightly different frequencies, so we are able to reconstruct the wave front arrival time by utilizing the phase difference. Thus, the flying time of ultrasound is much more accurate. The optimal parameters of dual frequency method are proposed to reach the best result of measurement. By experimental results, the maximum error of traditional measurement is reach to 50.21mm.Dual frequency method with optimal parameters improve to 7.6mm. After transmitting first frequency of ultrasound, it must await 4.652ms to transmit second frequency of ultrasound. This is to avoid energy coupling.
