- 學位論文
應用HHT於機場鋪面糙度指標改善之研究
Improvements in Pavement Roughness Index for Airports Using Hilbert-Huang Transform
摘要
機場鋪面平坦度與航機行駛安全有一定之相關性，其與航機動態反應亦有密切之關係；倘航機行駛於平坦度不佳之鋪面上，不但會使得乘坐者感到不適，於航機與鋪面剖面互相影響之劇烈垂直震動下，更可能造成機師無法準確判讀儀表板及影響操作上之困難，且機身結構與零件亦會產生疲勞破壞，而鋪面結構也會因此受到永久性之損害。故一良好之機場鋪面平坦度指標不僅可降低鋪面養護與機身之維修成本，更可提升航機行駛安全。 本研究首先藉由文獻回顧瞭解各平坦度指標之演算邏輯，並且利用各指標之演算邏輯、評估門檻、小波能量與評估方法等方面探討其適用性，結果發現現存機場鋪面平坦度指標與評估方法多數僅探討剖面之凹陷與隆起。其中，僅PRIA指標為以小波轉換為基礎，由分析航機動態反應與剖面波長特性之關係發展而成，由於該指標較能指出航機動態反應受鋪面剖面特性之影響，故本研究主要針對PRIA以進行指標之訊號處理方式與演算邏輯之改善。由文獻回顧得知HHT為利用EMD拆解訊號，可有效分析非穩態且非線性之自然界訊號，故以各機型之航機動態反應與波長特性分析為基礎，採用HHT進行原始剖面之訊號處理，並加入機場跑道實際使用情形如航機組成、起降速度分佈與起降位置等因素，進行指標之改善，將改善後之指標定名為PRIA2，最後以NASA建議之最大可接受垂直向加速度值0.4 g訂定評估門檻值。 PRIA2為利用HHT進行剖面訊號之處理，並加入跑道區段使用頻率之概念，除可提供機場管理單位進行養護工作時，其養護優先順序之考量，亦較符合各機場跑道實際之使用情形。
並列摘要
Pavement roughness index for airports is important for flight safety, and it relates to dynamic response of aircraft closely. While aircrafts take-off, land or taxi on roughness runway, it could cause passengers feel uncomfortable. In the worst case, pilots could operate hardly by the severe shock, and both aircraft structure and pavement structure could have fatigue damage. To avoid influence of these cases on flight safety, airport managers need a good pavement roughness index for airports. The objective of this research based on PRIA to improve the algorithm by changing signal analysis method and adding runway situations as parameters, such as aircraft velocity, touchdown/take-off point and ratio of aircraft types in the same airport. According to the previous researches, HHT is one method to analyze nonlinear and non-stationary signal, and it is suitable for pavement profile analysis. In order to develop a better index, this research used HHT to decompose profile into parts of IMF, and established the correlation among observed aircraft types, speed distribution and various wavelengths by simulation. Finally, PRIA2 was determined by different airports parameters, and the threshold was determined by the maximum acceptable vertical acceleration 0.4g which is NASA recommended. Because PRIA2 used HHT to analyze profile and add the concept of frequency of aircrafts take-off/land/taxi on runway sections, PRIA2 could not only provide information of pavement management, but also provide a real runway-to-aircraft dynamic response.