無人自走車整合設計與實驗

Abstract

本研究目的為發展出一具備精準定位與障礙物偵測規避的戶外自動導航車系統，該系統包含一移動載具、主控站與參考站。移動載具含有移動用的馬達與伺服系統，障礙物偵測用的雙眼照相機與超音波感測器，定位用的GPS 接收系統、電子羅盤以及通訊用的無線網卡；參考站中則具備第二組GPS接收機以提供定位的額外資訊，主控站則是負責接收移動站的資訊以作為監測之用。 本系統首先透過移動載具與參考站中的GPS接收機以及無線網路通訊，達成差分定位法的實現，並導入CSC(Carrier Smoothed Code)演算法提供移動載具當前的位置資訊，再配合電子羅盤來提供載具的姿態資訊；另外由雙眼相機擷取影像資料，透過雙眼立體視覺演算法來偵測前方障礙物，並配合超音波感測器來感測位於視覺死角或過於鄰近的障礙物，當無人車的終點位置設定並啟動後，透過上述感測器所提供的資料再結合路徑避障演算規劃，使無人車能夠閃躲環境中的障礙物並且抵達終點。 本研究發展的自動導航車系統成功的整合前述的各種感測器軟硬體，使移動載具可以在不同環境下避開障礙物並且抵達終點，實驗證實本研究所提出的整合方法確實可行。

The purpose of this investigation is to develop an unmanned vehicle system with precise positioning and obstacle detection and avoidance . The system is consisting of three parts : an unmanned vehicle unit , a main station and a reference station . The unmanned vehicle unit includes a servo motor system and motion control card for motion control ,an ultrasonic range sensor for obstacle detection , a stereo camera for obstacle detection and positioning , a compass and a GPS receiver to provide vehicle atitude and position data. The reference station include another GPS receiver to afford positioning data ,and the main station is to monitor and control the whole systems. We use Carrier smoothed Code(CSC) method here to calculate the vehicle position with the GPS receivers on unmanned vehicle and reference station .Some compensation strategy is adapted in CSC method to improve the performance of positioning to provide precise position data for unmanned vehicle control. For obstacle-avoiding , we integrate the stereo camera system to detect and position the obstacles in front of the vehicle ,and ultrasonic sensor to detect obstacles that are near the vehicle .After detecting the obstacles , a map then is built that indicate the relationship between vehicle and obstacles .We can design a reference path for the vehicle to track and avoid the obstacles. By using various obstacle-avoidance modes and the goal-approaching mode, the unmanned vehicle can reach the destination without colliding with surrounding obstacles. The experimental result shows that the proposed integration scheme is feasible.