- 學位論文
適路性先進汽車頭燈系統之建立
Development of an Adaptive Advanced Automobile Headlight System
摘要
目前多數車輛均以固定式頭燈照明系統來提供前方路面照明，此系統極易導致車輛行經彎道或上下坡路時產生照明死角，無法提供駕駛者前方路面路況資訊，而導致增加交通意外事故發生機率，現階段已有許多車廠研發出適路性先進頭燈系統(Adaptive Front-light System，AFS)來改善傳統式頭燈的缺點，改善的方式如車輛姿態或道路狀況改變時，保持頭燈光束符合法規規範之照射角度，使前方路面保持應有的照明視野及車輛行經道路迴轉半徑時，預先調整頭燈照射光束角度至正確的前方彎道上，使駕駛者能事先看清前方路面狀況以增加臨場反應時間，但此頭燈系統普遍仍有系統反應慢、成本高及調整角度不精確等問題尚須解決，尤其是系統反應時間過長的問題，導致頭燈系統無法對行進間因路面狀況引起之中高頻振動進行頭燈光束即時動態調整；有鑑於此，本論文除了自行建立一套適路性先進頭燈系統外，亦將就此缺失進行分析探討，使適路性先進頭燈系統功能更臻完善。 而創新適路性先進頭燈系統則運用LED (light emitting diode)作為頭燈照明光源，並以陣列編排及連續性明亮區塊快速變換的方式，達到照射光束隨路況變化而調整角度的控制目的，並運用LED陣列編排的優勢，由傳統頭燈的單維照射角度提升為二維照射角度，且可設定控制系統於不同道路環境時，開啟符合路況環境之高彈性光型分布型態，大幅提升頭燈照射效率及照明範圍。 經實際測試後，頭燈照射光束能隨路況變化而精確調整照射角度，使前方路面隨時保持充足的照明視野；而行進間路面狀況引起之中高頻振動，則經由截止頻率5Hz的低通濾波器來控制不必要的高頻光束調整，減少駕駛者視覺負擔及增加照明效率；另外控制頭燈下側及左右側LED陣列時，可投射出符合短距離及大範圍的城鎮照明，而遠距離大範圍照射，則改由控制頭燈上側LED陣列來滿足鄉野照明需求，以此設計編排原則，便可投射出山道照明與十字路口照明光型型態，有效改善現有主動式頭燈照明效率及照射範圍，使駕駛者專注於路況資訊同時，亦能提升行車與用路人安全，減少意外事故發生機會。
並列摘要
Nowadays, most vehicles apply fixed headlight system to provide illumination for the front road, but it doesn’t allow vehicles to project headlight beam onto road properly when making turns or cruising up and down hills. Therefore, drivers don’t get enough information about road conditions and then have traffic accidents easily. Many car manufactures have developed new generation of automobile headlight system, which is known as Adaptive Front-light System (AFS), to improve the traditional headlight system. The way it improves the headlight system is to change beam directions when vehicle attitudes and road conditions changed in order to keep the beam directions always fulfilling vehicle regulations and providing good visions for drivers. When making turns, headlight control system could pre-adjust headlight beam to avoid drivers crashing to the obstacles on the front road and could increase driver’s reaction times during turning. But current commercial headlight systems have problems of long system reaction time; high cost and inaccurate beam adjustment. among these problems, long system reaction time makes a headlight system be not able to adjust beam direction quickly. Especially in the adjustment for the mid-to-high frequency road vibration. Therefore, we build an AFS and discuss the defections of current headlight systems to hope that the function of AFS become perfectly. The innovative adaptive headlight system applies LED (light emitting diode) array as headlight sources. Therefore direction of headlight beam could be changed continuously and quickly according to road conditions. We apply the advantage of LED array to improve traditional headlight system from one-dimension projection to two-dimension projection. Therefore, the AFS system can provide appropriate beam patterns to fit different road conditions, and then increases headlight illumination and efficiency. The experimental results show that the controlled headlight beam could change with road condition and adjusts beam direction accurately. It kept front road having sufficient illumination. Besides, to eliminate mid-to-high frequency beam vibration caused by roads in driving, we applied a 5Hz low-pass filter to remove unnecessary high-frequency headlight beam adjustment. By this way, it reduced driver’s vision burden and increased efficiency of illumination on the front road. Finally, we activate different areas of LED array of headlight to project short distance and large area illumination onto town. For long distance illumination, we changed down side LED array to up side LED array of headlight to conform onto suburban. Following this concept, LED array of headlight could project mountain and cross-section mode of beam pattern, which improves headlight illumination and area of projection efficiently. Then drivers can focus on road information; meanwhile increase the safety of drivers and pedestrians to reduce car accidents.