無人載具之避障與路徑規劃

Abstract

本論文的主旨為發展一戶外自動導航車系統，系統包含主控站、參考站和無人載具三個部份。無人載具整合了GPS接收機、電子羅盤、雙眼相機和四個超音波感測器等感測元件，導航車在行進過程中偵測到障礙物進入其安全範圍內時，可藉由感測器偵測並配合路徑規劃來進行避障，並往終點前進。載具之位置資訊利用全球定位系統（GPS）來取得，方位角則用電子羅盤輸出獲得，經由無線網路構成的各次系統資訊交換機制，使主控站得以監控載具行為。 在避障控制方面，我們利用超音波感測器和雙眼相機來偵測障礙物距離。雙眼相機係利用映射在相機的兩個影像平面上映射點的距離差，來計算出障礙物與相機之間的距離。在超音波感測器方面，利用VHDL語言配合FPGA開發板設計一控制四顆超音波感測器輸出入電路，再透過超音波感測器得到的距離資訊，判斷是否有障礙物在安全範圍內並配合路徑規劃理論使無人載具行向終點。在定位方面，為了提高定位的準確度，使用載波相位三次差分法（KGPS）進行定位。 本篇論文最後以具體實驗驗證所發展之系統確實可行。

The main theme of this thesis is to develop an integrated navigation and control system for an unmanned vehicle. This system consists of three parts which are main- station, reference-station, and unmanned vehicle. There are various sensors on the vehicle such as a Global Position System(GPS), an electronic compass, a camera and four ultrasonic sensors. The vehicle uses the stereo-vision camera and ultrasonic sensors to detect the distance between the vehicle and the obstacle, electronic compass to measure the vehicle’s posture and GPS information to determine the vehicle’s position. The data exchange mechanism between sub-systems is set up through a wireless network. The task of obstacle avoidance and path-planning is using ultrasonic sensors and stereo-vision camera to detect the distance between obstacle and vehicle .Use these information from GPS, electronic compass and distance-detect sensors with vector field method to create the path，avoid the obstacle and go to the target . The operation of four ultrasonic sensors is designed by VHDL language and implemented by FPGA. The KGPS is used to set the vehicle’s position. Experimental results show the effectiveness of our proposed navigation and control methodology.